Some of their research found that boys' emotional reactivity was eventually "restricted or perhaps more change-worthy than the reactivity of girls," Dr. Tronick noted in an email.
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We can't risk fatigue by attempting to match Trump's reactivity.
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The control rods slipped into the reactor to slow reactivity.
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"This decreases emotional reactivity, which can be a superpower," says Ferriss.
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"This decreases emotional reactivity, which can be a superpower," he says.
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The rods contained boron carbide, which hampered reactivity, but the Soviets decided to tip them in graphite, which facilitated reactivity; it was a bid to save energy, and therefore money, by lessening the rods' moderating effect.
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For sure that's increasing the demand, in terms of reactivity, to be quick.
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Over time, narcissism increases in people with high wellbeing and low emotional reactivity.
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I felt like I was on Adderall, minus the body aches and emotional reactivity.
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They also had less reactivity to stressors, which could imply that they're always activated.
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"Equity market reactivity increases when equity markets are rallying over the prior month," Deshpande added.
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Afterward, students who received the intervention showed half the cardiovascular reactivity of the control group.
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Parents are an integral piece in a powerful system for regulating children's stress and emotional reactivity.
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Acceptance is the basic premise of mindfulness meditation, a practice that helps reduce stress and reactivity.
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According to Posner, "kids with ADHD oftentimes have emotion-related symptoms," including emotional reactivity and poor frustration tolerance.
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The kind of freedom I&aposm talking about is not being trapped in the unconscious pattern of reactivity.
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Because of potential "cross reactivity" with other flaviviruses, the antibody test is not enough to confirm a past Zika infection.
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This skin type is also known to have a greater propensity to reactivity, breakouts, and hormonal flare-ups (for women).
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Studies have also suggested that dog owners have lower reactivity to stress and faster recovery of blood pressure following stressful events.
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It slows your ability to process information and problem solve, kills your creativity, and catapults your stress levels and emotional reactivity.
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Though there was minimal difference in cortisol levels among women, in men, higher narcissism predicted greater cortisol reactivity and worse mood.
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The adjustments reduce the funds' reactivity to changes in volatility at a time when these types of products have drawn regulators' scrutiny.
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First, in a world where reactivity and sensitivity are at a fever pitch, it's important to consider the power of the audience.
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Indeed, studies show that an optimistic approach blunts reactivity to stress, curbing the outpouring of hormones that can debilitate body and mind.
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"Given the somewhat close homology between SARS and the new novel coronavirus, there could be some cross-reactivity there that could be utilized."
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Early in life, the mere presence of a parent reduces a child's levels of cortisol, a major stress hormone, and downregulates their amygdala reactivity.
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This thin, yet ultra strong, material has two properties that make it ideal for this purpose: its ability to channel light and its reactivity.
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Foy and Kobylinski's antibody panels showed a cross-reactivity to dengue and yellow fever, meaning they had been vaccinated or exposed to those viruses.
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"It's as if people learn to activate these patterns, and get used to them, and as a result their reactivity goes down," he says.
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When the promise is not forthcoming, however, or the pain worse than we feared, we flip-flop between two states: paralysis and over-reactivity.
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Before election day, do your research and know your choices, paying attention to not getting caught up in the media drama and others' reactivity.
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In Zen, he explains, the core aim is to sit with your mind and your heart; to cultivate silence around non-reactivity; to just be.
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Those who celebrated the Facebook revolution and the Twitter revolution were celebrating the replacement of (relatively) calm reflection with the politics of reactivity and passion.
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Far from relying on data from other trials, or patients, the experiment will test Donna's own cancer for its reactivity against a panel of medicines.
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Edelstein's and other research suggests that narcissists have higher cortisol and cardiovascular reactivity in socially threatening situations, like when they're being watched or judged. Why?
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But, given carbon's high chemical reactivity compared with gold's, it is a fair bet that macrophages will be even more likely to notice and swallow it.
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Even non-nicotine vapes seemed to have the same amount of DNA reactivity as filtered cigarettes, according to the study recently published in ACS Sensors. Bummer.
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In the 1950s, Dr. Roberts played a crucial role in the explosive growth of physical organic chemistry, a field that studies the reactivity of biological compounds.
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"Practicing mindfulness may decrease physiological stress reactivity and increase resilience to stress," said Kia Gluschkoff of the University of Helsinki, who also wasn't involved in the study.
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When doctors tested his skin reactivity with a small amount of vaping fluid, his symptoms worsened, raising the possibility that the e-cigarette fluid caused his reaction.
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However, the lessened amygdala reactivity only showed while they were engaged in mindfulness, suggesting we need more continued practice if we want the changes to be permanent.
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Because of the potential for cross-reactivity, positive serology results are tested again with a more sensitive, confirmatory test called a plaque reduction neutralization test or PRNT.
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Tiger snake antivenom has an extraordinary level of "cross reactivity" against other snake species, meaning it can neutralize the lethal effects of venomous bites in many other cases.
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Ms. Haddock said the company had patents pending related to robotics, biomimicry and engineering of the device, and hoped to integrate sensors and reactivity in the next iteration.
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The last and most difficult was the C.R.T. — a cardiac-reactivity test, in which patients' coronary arteries are injected with drugs that trigger either vascular contraction or relaxation.
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However, within a group of foods, such as fish, people may show "cross-reactivity," meaning that if they react to tuna, for instance, they may also react to cod.
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The erratic and mean-spirited reactivity and cavalier disregard of basic facts that we have seen throughout the year have come into even sharper relief these past few days.
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Although there are still many unanswered questions, we know that the following characteristics make up the HSP trait: hypersensitivity to external stimuli, deeper cognitive processing, and high emotional reactivity.
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Raw produce and nuts Cross-reactivity with pollen and grasses can also cause some people to have allergic reactions to raw fruits such as apples, peaches, bananas, melons, and tomatoes.
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"If the brain has produced them itself, they may be safely encased within some kind of membrane or cellular envelope in order to reduce their [in-cell] reactivity," said Maher.
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The E.P.A.'s risk management program ignores this class of hazardous chemicals, instead only requiring companies to address about 150 chemicals selected for toxicity and flammability, but not their reactivity.
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Stress reduction, improvements in memory function and ability to focus, and decreases in emotional reactivity are just a few of the ways mindfulness can make your brain straight-up function better.
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The task he proposes entails distinguishing between what is to be accepted as the natural condition of life itself (the unfolding of experience) and what is to be let go of (reactivity).
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This reactivity, combined with the fact that it takes an average of 110 weeks for an individual experiencing a first psychotic episode to get that treatment, means the current structure is inadequate.
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Hydrogen's reactivity poses more of a challenge since it will penetrate steel causing hydrogen-induced cracking and hydrogen embrittlement, both of which can cause pipeline failure unless expensive specialty steels are employed.
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Because their aggravated symptoms didn't require them to be smelling the chemical, Andersson and Claeson think perhaps people with MCS could have altered trigeminal reactivity, and will continue to look into that.
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Hydrogen's reactivity poses more of a challenge since it will penetrate steel causing hydrogen-induced cracking and hydrogen embrittlement, both of which can cause pipeline failure unless expensive speciality steels are employed.
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"There was a global decrease in brain reactivity to different cognitive and emotional stimuli," Ms. Kerr said, theorizing that these experiences may be functioning as a recalibration of a person's distress tolerance.
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" Scientists are also looking at the 2003 outbreak of SARS, Fauci said, adding that "there could be some cross-reactivity" between the SARS virus and the new coronavirus "that could be utilized.
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"Cornell astronomer and co-author Jonathan Lunine noted that nine years ago, a National Academies of Sciences report concluded, "If life is an intrinsic property of chemical reactivity, life should exist on Titan.
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"This deposition has proved to be a trigger event for Ms. Germanotta, and she has experienced in the past few hours some PTSD reactions which is causing some trauma and emotional reactivity," said Snyder.
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In a 2016 study published in the American Journal of Clinical Hypnosis, it was found that people who played fantasy role-playing games scored higher on the Davis Interpersonal Reactivity Index, which tests empathy.
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AND GUESS WHAT MR. CRAPPY THIEF: you stole yourself a book on dog reactivity, chicken flavored dog treats, doggy dental chews and a nifty little pouch to carry dog treats and poop bags on walks.
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Interactive stations within the exhibition enable visitors to replicate the light tests that reveal the reactivity of certain substances, like rose madder and indigo, while also affirming the presence of nonreactive colors, like cinnabar and Egyptian blue.
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Spices have varying levels of reactivity to ozone, a key ingredient in smog formation; for example, star anise, which contains high levels of volatile sesquiterpenes, might act as an ozone sink, reducing its levels and improving air quality.
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" This is normal, she says, but if we can identify our anxiety-driven reactivity, "we can get some distance from it, rather than being propelled into action before we have calmed down enough to do our best thinking.
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To determine whether you're dealing with a sleepwalker, as opposed to, say, a night owl (or someone with another, more worrisome form of parasomnia), watch for open eyes, a blank expression, physical clumsiness and a lack of reactivity.
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But there were surprises too: The dust's chemical reactivity, measured in its ability to create reactive oxygen species (a kind of molecule you might call a free radical) had nothing to do with how likely it was to cause damage.
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They don't yet know why a gratitude practice would increase reactivity to stress, Hirshberg says, but one theory is that because gratitude involves remembering a time when you felt grateful, it could increase your inward focus on yourself and your perspective.
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According to cue reactivity theory, which holds that people can develop learned responses by being presented with certain stimuli or cues, such food cues trigger food cravings for the food that's shown and subsequently lead to the actual eating behavior.
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But a propensity for reactivity does not mean you are doomed to a life of suffering through hot summers armed with nothing but a paper fan and a prayer while everyone else on the subway platform spritzes their forbidden minty elixirs around you.
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Even if Raicovich's departure from the Queens Museum exemplifies how forcefully the powers that be are blocking that vision from being put into practice, I hope to see it develop this year as people tire of the mental distraction and reactivity that has become our everyday under Trump.
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This end is not inevitable, but if we are to continue to make one out of many, leaders of both parties will have to step back from the reactivity of the present and take up the more arduous task of weaving a new national narrative in which all Americans can see themselves.
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"Conservatives approach the situation from the start with greater reactivity to threat, a greater prior belief to the level of danger in the world, so it is logical for the conservative to take more seriously information about hazards than the liberal does," Daniel Fessler, the University of California Los Angeles professor behind the study, told the Atlantic's Olga Khazan.
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She also researched carbanion reactivity, with emphasis on reactivity and structure of ion pairs.
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Reactivity then refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. In pure compounds, reactivity is regulated by the physical properties of the sample. For instance, grinding a sample to a higher specific surface area increases its reactivity. In impure compounds, the reactivity is also affected by the inclusion of contaminants.
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If the reactivity is positive, the reactor is supercritical. If the reactivity is negative, the reactor is subcritical. The term "neutron economy" is used not just for the instantaneous reactivity of a reactor, but also to describe the overall efficiency of a nuclear reactor design.
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Despite the structural and bonding commonalities of benzene and pyridine, their reactivity differ significantly. Instead, in terms of its reactivity, pyridine more closely resembles nitrobenzene.
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Reactivity controlled compression ignition (RCCI) is a form of internal combustion developed at the Engine Research Center, University of Wisconsin, Madison, by the research group of Wisconsin Distinguished Professor Rolf Reitz. During RCCI combustion, well-mixed low-reactivity fuel and oxidizer (typically air) are compressed but not reaching auto-ignition. Later, still during compression cycle, high-reactivity fuel is injected to form a local mixture of low- and high-reactivity fuel. Finally the whole fuel charge is ignited near top dead center of the piston by injection of high-reactivity fuel.
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Rather, an excess of fuel is inserted with reactivity control mechanisms, such that the reactivity control is inserted fully at the beginning of life to bring the reactor from supercritical to critical; as the fuel is depleted, the reactivity control is withdrawn to support continuing fission. In a fast breeder reactor, the above applies, though the reactivity from fuel depletion is also compensated by breeding either or and from thorium-232 or , respectively.
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Complexes with fewer than 18 valence electrons tend to show enhanced reactivity. Thus, the 18-electron rule is often a recipe for non- reactivity in either a stoichiometric or a catalytic sense.
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Lilly co-founded and served the CTO for Reactivity, a start-up focused on consulting on technically difficult websites and incubating new companies. Cisco Systems bought Reactivity in 2007 for $135 million.
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Complexes of the type M(DIP)Ln exhibit diverse reactivity.
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There are no articles found about the reactivity of methedrone.
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In the operation of a nuclear reactor, criticality is the state in which a nuclear chain reaction is self-sustaining—that is, when reactivity is zero. In supercritical states, reactivity is greater than zero.
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Benzylic groups are related to allyl groups; both show enhanced reactivity.
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To control large amounts of excess fuel reactivity without control rods, burnable poisons are loaded into the core. Burnable poisons are materials that have a high neutron absorption cross section that are converted into materials of relatively low absorption cross section as the result of neutron absorption. Due to the burn-up of the poison material, the negative reactivity of the burnable poison decreases over core life. Ideally, these poisons should decrease their negative reactivity at the same rate that the fuel's excess positive reactivity is depleted.
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The SSR is self-controlling and no mechanical control is required. This is made possible by the combination of a high negative temperature coefficient of reactivity and the ability to continually extract heat from the fuel tubes. As heat is taken out of the system the temperature drops, causing the reactivity to go up. When the reactor heats up the reactivity goes down.
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Serological Relationships: Antigen determinants are type- specific and group-specific. Antigen determinants that possess type-specific reactivity are found on the envelope. Antigen determinants that possess type- specific reactivity and are involved in antibody mediated neutralization are found on the glycoproteins. Cross-reactivity has been found among some species of the same serotype, but not between members of different genera.
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Lang EW, Kasprowicz M, Smielewski P, Santos E, Pickard J, Czosnyka M. Short pressure reactivity index versus long pressure reactivity index in the management of traumatic brain injury. J Neurosurg. 2015 Mar; 122(3):588-94.
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Reanalysis of various types of ambident organic system reveals that thermodynamic/kinetic control describes reactivity of organic compounds perfectly, whereas the HSAB principle fails and should be abandoned in the rationalization of ambident reactivity of organic compounds.
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The mechanism of how these additives increase reactivity is still being researched.
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Thus, although molecular structure generally predicts intrinsic reactivity, quantitative predictions are limited.
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Enamines act as nucleophiles that require less acid/base activation for reactivity than their enolate counterparts. They have also been shown to offer a greater selectivity with less side reactions. There is a gradient of reactivity among different enamine types, with a greater reactivity offered by ketone enamines than their aldehyde counterparts. Cyclic ketone enamines follow a reactivity trend where the five membered ring is the most reactive due to its maximally planar conformation at the nitrogen, following the trend 5>8>6>7 (the seven membered ring being the least reactive).
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N-iodosuccinimide/triflic acid. The reactivity of glycosyl donors depend very much on their protection groups, which led to classification of these compounds into three categories of reactivity: Disarmed, armed, and superarmed. The so-called “armed-disarmed” principle The concept of armed and disarmed glycosyl donors refers to the increased reactivity of benzylated over benzoylated glycosyl donors, a phenomenon observed very early,H. Paulsen, Angew. Chem. Int.
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The solvent used in anionic addition polymerizations are determined by the reactivity of both the initiator and nature of the propagating chain end. Anionic species with low reactivity, such as heterocyclic monomers, can use a wide range of solvents.
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Both kinds of reactivity are known, but reaction on carbon is more common.
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Carbon–halogen bond strengths, or bond dissociation energies are of 115, 83.7, 72.1, and 57.6 kcal/mol for bonded to fluorine, chlorine, bromine, or iodine, respectively. The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of reactivity and cost. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.
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This feature influences their chemical reactivity. The pimaric-type acids are dextropimaric and isodextropimaric.
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First, we investigated the reactivity of 80 plasma samples from primigravid or multigravid women.
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When metals are near the bottom of the reactivity series, their compounds generally decompose easily at high temperatures. This is because stronger bonds form between atoms towards the top of the reactivity series, and strong bonds break less easily. For example, copper is near the bottom of the reactivity series, and copper sulfate (CuSO4), begins to decompose at about 200 °C, increasing rapidly at higher temperatures to about 560 °C. In contrast potassium is near the top of the reactivity series, and potassium sulfate (K2SO4) does not decompose at its melting point of about 1069 °C, nor even at its boiling point.
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Cross-reactivity, in a general sense, is the reactivity of an observed agent which initiates reactions outside the main reaction expected. This has implications for any kind of test or assay, including diagnostic tests in medicine, and can be a cause of false positives. In immunology, the definition of cross-reactivity refers specifically to the reaction of the immune system to antigens. There can be cross-reactivity between the immune system and the antigens of two different pathogens, or between one pathogen and proteins on non-pathogens, which in some cases can be the cause of allergies.
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Cross reactivity may also occur between a pathogen and a protein found on a non-pathogen (i.e. food.) There may even be cross reactivity between two non-pathogens; for example, Hevein-like protein domains are a possible cause for allergen cross- reactivity between latex and banana. Cross-reactivity may be caused by identical carbohydrate structures on unrelated proteins from the same or different species. Such cross-reactive carbohydrate determinants (CCDs) are an issue in allergy diagnosis, where about a fifth of all patients displays IgE antibodies against Asn-linked oligosaccharides (N-glycans) containing core α1,3-linked fucose.
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Cortisol awakening response provides an easy measure of the reactivity capacity of the HPA axis.
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Mosher's acid chloride, the acid chloride form, is sometimes used because it has better reactivity.
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A series of solution kinetics studies of LDA - mediated reactions suggest that lower aggregates of enolates do not necessarily lead to higher reactivity. Also, some Lewis bases increase reactivity of organolithium compounds. However, whether these additives function as strong chelating ligands, and how the observed increase in reactivity relates to structural changes in aggregates caused by these additives are not always clear. For example, TMEDA increases rates and efficiencies in many reactions involving organolithium reagents.
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The Hiyama coupling was developed to combat the issues associated with other organometallic reagents. The initial reactivity of organosilicon was not actually first reported by Hiyama, as Kumada reported a coupling reaction using organofluorosilicates shown below. Organosilanes were then discovered, by Hiyama, to have reactivity when activated by a fluoride source. This reactivity, when combined with a palladium salt, creates a carbon-carbon bond with an electrophillic carbon, like an organic halide.
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Different protecting groups on either the glycosyl donor or the glycosyl acceptor may affect the reactivity and yield of the glycosylation reaction. Typically, electron-withdrawing groups such as acetyl or benzoyl groups are found to decrease the reactivity of the donor/acceptor and are therefore termed "disarming" groups. Electron-donating groups such as the benzyl group, are found to increase the reactivity of the donor/acceptor and are therefore called "arming" groups.
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More specifically, its 4fn electron configurations have almost no effect on its chemical reactivity and its electrostatic interactions require optimizing through ligand geometries. Moreover, the reactivity of the f-block element complexes relies heavily on their sterics. In other words, a sterically saturated structure offers the best stability, and so, both ligand size or metal size can be altered to modify the reactivity. These special properties allow the following reactions to occur.
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Sleep deprivation alters pupillary reactivity to emotional stimuli in healthy young adults. Biological Psychology, 80(3), 300-305. doi:10.1016/j.biopsycho.2008.10.010 When exposed to positive stimuli, sleep deprived participants showed amplified emotional reactivity throughout various midbrain, striatal, limbic, and visual processing brain regions.
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Broadly speaking, reactivity of the compounds is greatest for the iodides and lowest for the fluorides.
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The dextrinoid reactivity of the context and the setae-like elements distinguish this genus from Polyporus.
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Antigenic cross-reactivity suggests that E. phaeomuriformis may have originated as multicellular variant of E. dematitidis.
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Thus, EP3 appears to serve an important role in reducing allergic reactivity at least in mice.
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Surface reactivity can also be directly monitored through microcalorimetry using probe molecules that undergo measurable changes.
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Monobactam antibiotics exhibit no IgE cross-reactivity reactions with penicillin but have shown some cross reactivity with cephalosporins, most notably ceftazidime, which contains an identical side chain as aztreonam. Monobactams can trigger seizures in patients with history of seizures, although the risk is lower than with penicillins.
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There are more esoteric electronic effects but these are among the most important when considering chemical structure and reactivity. Special computational procedure was developed to separate steric and electronic effects of an arbitrary group in the molecule and to reveal their influence on structure and reactivity.
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One of the most developed areas of phosphaalkyne chemistry is that of cycloadditions. Like other multiply bonded molecular fragments, phosphaalkynes undergo myriad reactions such as [1+2] cycloadditions, [3+2] cycloadditions, and [4+2] cycloadditions. This reactivity is summarized in graphical format below, which includes some examples of 1,2-addition reactivity (which is not a form of cycloaddition). A graphic showing some prototypical reactivity espoused by the phosphaalkyne functional group, including 1,2-additions, [2+1] cycloadditions, [2+3] cycloadditions, and [2+4] cycloadditions.
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Only the remaining groups at positions C3, C4, C7, C15 vary for the different mycotoxins. In case of nivalenol each of the four remaining groups is a substituted hydroxyl group which add up to the reactivity in presence of hydrophilic compounds or subgroups respectively thanks to their polar characteristics. In acidic medium the keto group is capable of reacting with a proton promoting polarity and reactivity as well. But altogether the epoxide group is crucial for the reactivity of the molecule.
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Denaturing the protein may 'disarm' its function but allow the immune system to have an immune response thus creating an immunity without harming the patient. Cross reactivity has implications for flu vaccination because of the large number of strains of flu, as antigens produced in response to one strain may confer protection to different strains. Cross-reactivity need not be between closely related viruses, however; for example, there is cross-reactivity between influenza virus-specific CD8+ T cells and hepatitis C virus antigens.
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Persistent triplet state carbenes are likely to have very similar reactivity as other non-persistent triplet state carbenes.
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"Reactivity control in palladium-catalyzed reactions: a personal account" Pavel Kocovsky J. Organometallic Chemistry 687 (2003) 256-268.
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Strong negative temperature coefficient of reactivity causes damping of these oscillations, and is a desired reactor design feature.
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Evidence for immunological cross reactivity with cell surface tumor-necrosis-factor receptors. J. Biol. Chem. 265, 1531-1536.
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Other studies show that IgE reactivity to ω-5 gliadin increases greatly when deamidated or crosslinked to transglutaminase.
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In direct contrast, the positive emotions appeared to have no distinguishable autonomic responses. Positive emotions do not themselves generate cardiovascular reactivity, but instead quell any existing cardiovascular reactivity caused by negative emotions. Put differently, a prior state of negative emotional arousal may be a necessary backdrop to illuminate the cardiovascular impact of positive emotions. Assuming (as most emotion theorists do) that the cardiovascular reactivity sparked by certain negative emotions prepares the body for specific actions, the broaden-and-build theory suggests that positive emotions can speed recovery from—or undo—this cardiovascular reactivity and return the body to mid-range levels of activation suitable for pursuing a wider range of behavioral options.
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The RCCI combustion process requires two different fuels. Low-reactivity fuel gets injected into the intake ports with low pressure during the intake stroke. High-reactivity fuel gets injected into the cylinder with high pressure at the end of compression stroke. A throttle characteristic to Otto engines is not needed.
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Reviews of human trials report that for a confirmed tree nut allergy, up to one third of people will react to more than one type of tree nut. The cross reactivity among almond, walnut, pecan, hazelnut and Brazil nut is stronger than cross reactivity of these toward cashew or pistachio.
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The high reactivity of organoaluminium compounds toward electrophiles is attributed to the charge separation between aluminium and carbon atom.
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An overview on preparation, reactivity and properties of halogenated graphenes in available in ACS Nano journal free of charge.
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One of its most frequent uses is for percutaneous closures. Ethilon has good knot security and low tissue reactivity.
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Pentaphenylborole is known to show a wide range of reactivity, owing to its antiaromatic and highly Lewis acidic nature.
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The chemistry of thioesters and acid halides is similar, the reactivity being reminiscent of, but milder, than acid chlorides.
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In the steel making process, this method is used very commonly for duplex steel and some high reactivity metals.
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Testing was also performed on five icteric, five hemolyzed, and five lipemic serum specimens, and no reactivity was observed.
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The human body can employ cyanide-like umpolung reactivity without having to rely on the toxic cyanide ion. Thiamine (which itself is an N-heterocyclic carbene) pyrophosphate (TPP) serves a functionally identical role. The thiazolium ring in TPP is deprotonated within the hydrophobic core of the enzyme, resulting in a carbene which is capable of umpolung. Deprotonation of thiazole moiety in thiamine pyrophosphate results in ambivalent chemical reactivity Enzymes which use TPP as a cofactor can catalyze umpolung reactivity, such as the decarboxylation of pyruvate.
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As the structures of organolithium reagents change according to their chemical environment, so do their reactivity and selectivity. One question surrounding the structure-reactivity relationship is whether there exists a correlation between the degree of aggregation and the reactivity of organolithium reagents. It was originally proposed that lower aggregates such as monomers are more reactive in alkyllithiums. However, reaction pathways in which dimer or other oligomers are the reactive species have also been discovered, and for lithium amides such as LDA, dimer-based reactions are common.
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In immunology, cross-reactivity has a more narrow meaning of the reaction between an antibody and an antigen that differs from the immunogen. It is sometimes also referred to as crossimmunity or cross-protective immunity, although cross-reactivity does not necessarily infer cross- protection. In some cases, the cross-reactivity can be destructive, and immune response to one pathogen can interfere with or lower the immune response to a different pathogen. An adaptive immune response is specific to the antigen that stimulated it (called the immunogen).
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Nuclear power plants operate between these two points of reactivity, while above the prompt critical point is the domain of nuclear weapons and some nuclear power accidents, such as the Chernobyl disaster. A convenient unit for the measurement of the reactivity is that suggested by Louis Slotin: that of the dollar and cents.
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In the past, cue reactivity has been used in labs to instruct patients in beneficial coping skills that help them to avoid relapse. Virtual reality technology allows for a more effective approach to trigger physiological arousal than the standard cue reactivity methods used previously—primarily, presentation of paraphernalia or actor- based simulation.
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In addition, there is also a small risk of cross-reactivity in patients having experienced angioedema with ACE inhibitor therapy.
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1]propellane; or more generally the paddlanes, and pyramidane ([3.3.3.3]fenestrane). Such molecules are typically strained, resulting in increased reactivity.
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The gel electrophoresis step is included in western blot analysis to resolve the issue of the cross-reactivity of antibodies.
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Under EPA regulations, "characteristic hazardous wastes" are defined as wastes that exhibit the following characteristics: ignitability, corrosivity, reactivity, or toxicity.
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For example, chimpanzees show emotional stability, agreeableness and surgency, audiovisual reactivity, affect-extraversion, excitability-agitation, aggression affinity and social play.
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Oxaziridines with unsubstituted or acylated nitrogens are capable of nitrogen atom transfer, although this reactivity has received considerably less attention.
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Rubenfire's clinical and research interests include: Atherosclerosis detection, preventive cardiology, lipid management, pulmonary hypertension, coronary risk factors and vascular reactivity.
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Initiators is selected based on the reactivity of the monomers. Highly electrophilic monomers such as cyanoacrylates require only weakly nucleophilic initiators, such as amines, phosphines, or even halides. Less reactive monomers such as styrene require powerful nucleophiles such as butyl lithium. Reaction of intermediate strength are used for monomers of intermediate reactivity such as vinylpyridine.
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'Stability' should not be confused with reactivity. For example, an isolated molecule of an electronically excited state of the oxygen molecule spontaneously emits light after a statistically defined period. The half-life of such a species is another manifestation of its stability, but its reactivity can only be ascertained via its reactions with other species.
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In chemistry, a reactivity series (or activity series) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest. It is used to summarize information about the reactions of metals with acids and water, single displacement reactions and the extraction of metals from their ores.
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Tissue cross-reactivity assay is a standard method based on immunohistochemistry, required prior to phase I human studies for therapeutic antibodies. In drug screening, because many urine drug screens use immunoassays there is a certain amount of cross-reactivity. Certain drugs or other chemicals can give a false positive for another category of drug.
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Automated mobile pupillometer (Reflex by brightlamp, Inc.) NeurOptics, Inc. Pupillometer Results Screen An automated pupillometer is a portable, handheld device that provides a reliable and objective measurement of pupillary size, symmetry, and reactivity through measurement of the pupillary light reflex. Independent of examiner, an automated pupillometer eliminates variability and subjectivity, expressing pupil reactivity numerically so that both pupil size and reactivity can be trended for changes, just like other vital signs. An automated pupillometer also provides a reliable and effective way to quantitatively classify and trend the pupil light response.
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In medical tests, including rapid diagnostic tests, cross- reactivity can be either confounding or helpful, depending on the instance. An example of confounding that yields a false positive error is in a latex fixation test when agglutination occurs with another antigen rather than the antigen of interest. An example of helpful cross-reactivity is in heterophile antibody tests, which detect Epstein-Barr virus using antibodies with specificity for other antigens. Cross-reactivity is also a commonly evaluated parameter for the validation of immune and protein binding based assays such as ELISA and RIA.
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Prova: Rule- based Java Scripting for Distributed Web Applications: A Case Study in Bioinformatics, Reactivity on the Web Workshop, Munich 2006.
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Phosphaalkynes possess diverse reactivity profiles, and can be utilized in the synthesis of various phosphorus-containing saturated of unsaturated heterocyclic compounds.
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H2 is relatively unreactive. The thermodynamic basis of this low reactivity is the very strong H-H bond, with a bond dissociation energy of 435.7 kJ/mol. The kinetic basis of the low reactivity is the nonpolar nature of H2 and its weak polarizability. It spontaneously reacts with chlorine and fluorine to form hydrogen chloride and hydrogen fluoride, respectively.
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Armstrong et al. showed that the TMP-Turbo-Hauser base easily metalates ethyl-3-chlorobenzoate in the C2 position, while the same reaction carried out with the iPr-Turbo-Hauser base resulted in no metalation at all. Instead, an addition-elimination reaction occurs. Contrasting reactivity of iPr2NMgCl·LiCl and TMPMgCl·LiCl Another difference in reactivity was shown by Krasovskiy et al.
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Graphene is the only form of carbon (or solid material) in which every atom is available for chemical reaction from two sides (due to the 2D structure). Atoms at the edges of a graphene sheet have special chemical reactivity. Graphene has the highest ratio of edge atoms of any allotrope. Defects within a sheet increase its chemical reactivity.
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It can be generally stated that lithium tetrahydridogallate's reactivity is similar to lithium tetrahydridoaluminate's reactivity, but the first is less stable. This is due to the susceptibility of the gallium-hydrogen bonds to hydrolysis. As a consequence LiGaH4 is usually prepared in the absence of air. Lithium tetrahydridogallate violently reacts with water by releasing 4 moles of gaseous hydrogen.
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InHour is a unit of reactivity of a nuclear reactor. It stands for the inverse of an hour. It is equal to the inverse of the period in hours. One InHour is the amount of reactivity needed to increase the reaction from critical to where the power will increase by a factor of e in one hour.
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In the last few decades, researchers have identified a wide range of individual characteristics that reflect or are associated with sensitivity to environmental influences. These include specific aspects of child temperament (e.g., difficult temperament, negative emotionality, and impulsivity), physiological reactivity (e.g., high cortisol reactivity) and various genetic variants that can be combined into a polygenic score of sensitivity.
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The structure of isatuximab consists of two identical immunoglobulin kappa light chains and also two equal immunoglobulin gamma heavy chains. Chemically, isatuximab is similar to the structure and reactivity of daratumumab, hence both drugs show the same CD38 targeting. However, isatuximab shows a more potent inhibition of its ectozyme function. The latter gives potential for some non-cross reactivity.
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Rossi S, editor. Australian Medicines Handbook 2006. Adelaide: Australian Medicines Handbook; 2006. This, however, should be viewed in the light of recent epidemiological work suggesting, for many second-generation (or later) cephalosporins, the cross-reactivity rate with penicillin is much lower, having no significantly increased risk of reactivity over the first generation based on the studies examined.
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The reactivity of the NO2+ can be further enhanced with strong acids that generate the "super-electrophile" HNO22+. In this use, has been largely replaced by nitronium tetrafluoroborate []+[]−. This salt retains the high reactivity of NO2+, but it is thermally stable, decomposing at about 180 °C (into NO2F and BF3). Dinitrogen pentoxide is relevant to the preparation of explosives.
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When placed in benzylic or allylic positions, the strength of the C–H bond is decreased, and the reactivity of the methyl group increases. One manifestation of this enhanced reactivity is the photochemical chlorination of the methyl group in toluene to give benzyl chloride.M. Rossberg et al. “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim.
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Palladium fluoride is an insoluble powder used in infrared optical sensors, and in situations where reactivity to oxygen makes palladium oxide unsuitable.
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This reactivity is similar to the tendency of ethers with alpha hydrogen atoms to form peroxides. Reaction with chlorine produces alpha-chloroethers.
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The order of reactivity of alkoxides, K > Na >> Mg, is consistent with higher electron density on oxygen, hence increasing the alkoxide nucleophilicity.
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Mercaptoethanesulfonate contains both a thiol, which is the main site of reactivity, and a sulfonate group, which confers solubility in aqueous media.
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Thanks to our extensive coverage, our hability to fall back and our reactivity, we will not have to lay anyone off temporarily.
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Further publications have disclosed modifications of the Argauer and Landolt process directed towards improving the reactivity of the SiO2 and Al2O3 starting materials.
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Brucine can be detected and quantified using liquid chromatography-mass spectrometry. Historically, brucine was distinguished from strychnine by its reactivity toward chromic acid.
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Unlike the bismuth oxide, the presence of the acidic Si(IV) cations avoid the reactivity with CO2. Another bismuth silicate has formula Bi2O9Si3.
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4-IPO has three functional groups which determine the molecule's reactivity. These are the furan ring, the ketone group and the alcohol group.
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The coolant liquid may act as a neutron absorber, as a neutron moderator, usually as both but with one or other role as the most influent. In either case, the amount of void inside the reactor can affect the reactivity of the reactor. The change in reactivity caused by a change of voids inside the reactor is directly proportional to the void coefficient. A positive void coefficient means that the reactivity increases as the void content inside the reactor increases due to increased boiling or loss of coolant; for example, if the coolant act predominantly as neutron absorber.
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The number of control rods inserted and the distance by which they are inserted can be varied to control the reactivity of the reactor. Usually there are also other means of controlling reactivity. In the PWR design a soluble neutron absorber, usually boric acid, is added to the reactor coolant allowing the complete extraction of the control rods during stationary power operation ensuring an even power and flux distribution over the entire core. Operators of the BWR design use the coolant flow through the core to control reactivity by varying the speed of the reactor recirculation pumps.
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Heavy water is an extremely efficient moderator. As a result, reactors using heavy water, such as the CANDU, also have a high neutron economy. The quantity that indicates how much the neutron economy is out of balance is given the term reactivity. If a reactor is exactly critical—that is, the neutron production is exactly equal to neutron destruction—the reactivity is zero.
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The reactivity of picryl chloride is strongly influenced by the presence of three electron-withdrawing nitro groups. Consequently picryl chloride is an electrophile as illustrated by its reactivity toward sulfite to give the sulfonate: :ClC6H2(NO2)3 \+ Na2SO3 → NaO3SC6H2(NO2)3 \+ NaCl Picryl chloride is also a strong electron acceptor. It forms a 1:1 charge-transfer complex with hexamethylbenzene.
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Such large negative reactivity feedback allows the reactor to always be in a shutdown (subcritical) state when at temperatures exceeding 800°C. This provides security against all overpower scenarios, such as a reactivity insertion accident. The ability to shutdown is ensured through the removal of fuel assemblies along the core's edge to their storage inside the reactor tank. This renders the system subcritical.
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The stability of NHSis, especially 6π aromatic unsaturated five-membered examples, make them useful systems to study the structure and reactivity of silylenes and low-valent main group elements in general. Though not used outside of academic settings, complexes containing NHSis are known to be competent catalysts for industrially important reactions. This article focuses on the properties and reactivity of five-membered NHSis.
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The resulting set of potential neoantigens was used to assess T cell reactivity. Exome–based analyses were exploited in a clinical setting, to assess reactivity in patients treated by either tumor-infiltrating lymphocyte (TIL) cell therapy or checkpoint blockade. Neoantigen identification was successful for multiple experimental model systems and human malignancies. The false-negative rate of cancer exome sequencing is low—i.e.
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The behavior of the secondary phospholes, those with P−H bond, is dominated by the reactivity of this group. The parent phosphole readily rearranges by migration of H from P to carbon-2, followed by dimerization. Most phospholes are tertiary, typically P-methyl or P-phenyl. The nonaromaticity of these phospholes is manifested in their reactivity but the P−C bonds remain intact.
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It turns out that one of CFCs' most attractive features—their low reactivity— is key to their most destructive effects. CFCs' lack of reactivity gives them a lifespan that can exceed 100 years, giving them time to diffuse into the upper stratosphere. Once in the stratosphere, the sun's ultraviolet radiation is strong enough to cause the homolytic cleavage of the C-Cl bond.
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Competence and resilience in development. Annals of the New York Academy of Sciences, 1094(1), pp. 13-27. the impact of stress reactivity and family adversity on socioemotional behavior and school readiness,Obradovic, J. et al. (2010). Biological sensitivity to context: The interactive effects of stress reactivity and family adversity on socioemotional behavior and school readiness. Child Development, 81(1), pp. 270-289.
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Covalent modification of carbon nanotubes. Covalent modification attaches a functional group onto the carbon nanotube. The functional groups can be attached onto the side wall or ends of the carbon nanotube. The end caps of the carbon nanotubes have the highest reactivity due to its higher pyrimidization angle and the walls of the carbon nanotubes have lower pyrimidization angles which has lower reactivity.
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Cross-reactivity is found. Cross-reactivity between species of the same serotype, but not with species of another serotype and some species of the same serotype, but not with all. Although the degree of antigenic specificity varies with the degree of relatedness, the antigenicity is distinct from serogroups of the same genus. Most species in the genus are related antigenically.
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Coordinated ligands display reactivity distinct from the free ligands. For example, the acidity of the ammonia ligands in [Co(NH3)6]3+ is elevated relative to NH3 itself. Alkenes bound to metal cations are reactive toward nucleophiles whereas alkenes normally are not. The large and industrially important area of catalysis hinges on the ability of metals to modify the reactivity of organic ligands.
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Czosnyka M, Czosnyka Z, Smielewski P. Pressure reactivity index: journey through the past 20 years. Acta Neurochir (Wien). 2017 Nov; 159(11):2063-2065.
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They also found that MBCT reduced the connection of cognitive reactivity and depressive relapse, and that the increased self-compassion helped mediate this association.
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Pressure reactivity index is an emerging technology which correlates intracranial pressure with arterial blood pressure to give information about the state of cerebral perfusion.
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The measurement of vagal tone in humans has become a novel index of stress vulnerability and reactivity in many studies of populations with affective disorders.
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Conformations of ferrocene. Left: staggered; right: ecliptic. An important parameter is the angle between the two cyclopentadienyl ligands. Often the reactivity increases with increasing angle.
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Also, the theory that phlogiston is a substance released from burning and rusting material was eliminated with the new understanding of the reactivity of oxygen.
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These orders of reactivity are the same as those observed for reactions that are well established as proceeding through nucleophilic attack on a carbonyl group.
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Therefore, if reactivity increases beyond normal, the reduced moderation of neutrons will cause the chain reaction to slow down, producing less heat. This property, known as the negative temperature coefficient of reactivity, makes PWR reactors very stable. This process is referred to as 'Self-Regulating', i.e. the hotter the coolant becomes, the less reactive the plant becomes, shutting itself down slightly to compensate and vice versa.
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This was determined using the empathy quotient, which has three main scales: cognitive empathy, emotional reactivity, and social skills. Mirror touch synesthetes showed significantly higher empathy quotient scores in emotional reactivity than in controls. However synesthetes did not show higher scores in cognitive empathy and social skills. Thus empathy is multifaceted, and the tactile mirror system may not be fully responsible for the ability to empathize.
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Aromatic halogen groups are far less reactive than aliphatic halogen groups, which can exhibit considerable chemical reactivity. For aliphatic carbon-halogen bonds, the C-F bond is the strongest and usually less chemically reactive than aliphatic C-H bonds. The other aliphatic-halogen bonds are weaker, their reactivity increasing down the periodic table. They are usually more chemically reactive than aliphatic C-H bonds.
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PMDTA is used to modify the reactivity of organolithium compounds, which deaggregate in the presence of Lewis bases to enhance their reactivity. Commonly, the ditertiary amine TMEDA is used in these applications; it binds to the lithium center as a bidentate ligand. PMDTA behaves analogously, but since it is tridentate, it binds more strongly to lithium. In contrast to TMEDA, PMDTA forms monomeric complexes with organolithium compounds.
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Safety concepts rely on a negative temperature coefficient of reactivity and a large possible temperature rise to limit reactivity excursions. As an additional method for shutdown, a separate, passively cooled container below the reactor can be included. In case of problems and for regular maintenance the fuel is drained from the reactor. This stops the nuclear reaction and acts as a second cooling system.
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Fuel temperature coefficient of reactivity is the change in reactivity of the nuclear fuel per degree change in the fuel temperature. The coefficient quantifies the amount of neutrons that the nuclear fuel (such as uranium-238) absorbs from the fission process as the fuel temperature increases. It is a measure of the stability of the reactor operations. This coefficient is also known as the Doppler coefficient.
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The choice of aryl halide or pseudohalide substrate (sp2-carbon) is one of the factors that mainly influence the reactivity of the Sonogashira catalytic system. The reactivity of halides is higher towards iodine, and vinyl hallides are more reactive than analogous aryl halides. The rate of reaction of sp2 carbons. Vinyl iodide > vinyl triflate > vinyl bromide > vinyl chloride > aryl iodide > aryl triflate > aryl bromide >>> aryl chloride.
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Mitochondrial myopathies are types of myopathies associated with mitochondrial disease. On biopsy, the muscle tissue of patients with these diseases usually demonstrate "ragged red" muscle fibers. These ragged-red fibers contain mild accumulations of glycogen and neutral lipids, and may show an increased reactivity for succinate dehydrogenase and a decreased reactivity for cytochrome c oxidase. Inheritance was believed to be maternal (non-Mendelian extranuclear).
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If the methylene were a triplet, one would not expect the product to depend upon the starting alkene geometry, but rather a nearly identical mixture in each case. Reactivity of a particular carbene depends on the substituent groups. Their reactivity can be affected by metals. Some of the reactions carbenes can do are insertions into C-H bonds, skeletal rearrangements, and additions to double bonds.
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In addition to its reactivity to gut-associated lymphoid tissues, Act-1 antibody also stains large numbers of lymphocytes in rheumatoid synovium, and has been shown by Dr. A. A. Ansari of Emory University to prevent or delay onset of AIDS in a monkey-model of Simian Immunodeficiency Virus-induced AIDS. Thus, reactivity with this antibody may show widespread applicability in inflammatory processes of diverse etiologies.
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Furthermore, a faster behavioral reactivity is detected in the left hemisphere during SWS of the first night. The rapid awakening is correlated to the regional asymmetry in the activities of SWS. These findings show that the hemispheric asymmetry in SWS plays a role as a protective mechanism. SWS is therefore sensitive to danger and non-familiar environment, creating a need for vigilance and reactivity during sleep.
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Serological relationships between different members are found (among Feline calicivirus). Cross-reactivity is found. Cross-reactivity between species of the same serotype, but not with species of another serotype and some species of the same serotype, but not with all. Although the degree of antigenic specificity varies with the degree of relatedness, the antigenicity is distinct from canine caliciviruses, Norwalk virus serogroups of the same genus.
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1943 Reactor diagram using boron control rods Control rods are inserted into the core of a nuclear reactor and adjusted in order to control the rate of the nuclear chain reaction and, thereby, the thermal power output of the reactor, the rate of steam production, and the electrical power output of the power station. The number of control rods inserted, and the distance to which they are inserted, strongly influence the reactivity of the reactor. When reactivity (as effective neutron multiplication factor) is above 1, the rate of the nuclear chain reaction increases exponentially over time. When reactivity is below 1, the rate of the reaction decreases exponentially over time.
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During operation of a reactor the amount of fuel contained in the core decreases monotonically. If the reactor is to operate for a long period of time, fuel in excess of that needed for exact criticality must be added when the reactor is fueled. The positive reactivity due to the excess fuel must be balanced with negative reactivity from neutron-absorbing material. Movable control rods containing neutron-absorbing material is one method, but control rods alone to balance the excess reactivity may be impractical for a particular core design as there may be insufficient room for the rods or their mechanisms, namely in submarines, where space is particularly at a premium.
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Even though it gives 100% sensitivity, it has not been tested with human sera for cross-reactivity, and it may show a high false positive result.
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Therefore, surface structure serves an important role in surface reactivity, with the coordination environment at the solid-water interface changing intensity or rate of a reaction.
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In addition to autoimmune diseases, individuals experience higher immune reactivity (e.g. chronic dermatitis) and susceptibility to infections. Individuals also develop autoimmune diseases at a young age.
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Trimethylsilyl trifluoromethanesulfonate is a trifluoromethanesulfonate derivate with a trimethylsilyl R-group. It has similar reactivity to trimethylsilyl chloride, and is also used often in organic synthesis.
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Vicente, J; Abad, J.A.; Fortsch, W.; Lopez-Saez, M.J. Reactivity of ortho-palladated phenol derivatives with unsaturated molecules. Organometallics, 2004, 23, 4414-4429. DOI 10.1021/om0496131.
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Memory response, or "Retest Reactivity", usually takes 2 to 3 days after coming in contact with the allergen, and can persist for 2 to 4 weeks.
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For catalytic hydroboration, pinacolborane and catecholborane are widely used. They also exhibit higher reactivity toward alkynes. Pinacolborane is also widely used in a catalyst-free hydroborations.
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Specificity and cross-reactivity between multiple group 1 allergens is thought to stem from the differences and homologies in structure, particularly regarding the positions of epitopes.
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In the airways of patients with asthma, the expression of adenosine receptors is upregulated. Adenosine receptors affect bronchial reactivity, endothelial permeability, fibrosis, angiogenesis and mucus production.
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J. Phys. Chem. Lett., 2018, 9 (13), pp 3580–3585 . In 2010 it was shown that fluorographene can be transformed to graphene by treatment with KI. Nucleophiles can substitute the fluorine atoms and induce partial or full defluorination.Dubecký M, Otyepková E, Lazar P, Karlický F, Petr M, Čépe K, Banáš P, Zbořil R, Otyepka M Reactivity of Fluorographene: A Facile Way toward Graphene Derivatives. J. Phys. Chem. Lett., 2015, 6 (8), pp 1430–1434 The fluorographene reactivity is triggered by point defects.Medved M, Zoppellaro G, Ugolotti J, Matochová D, Lazar P, Pospíšil T, Bakandritsos A, Tuček J, Zbořil R, Otyepka M Reactivity of fluorographene is triggered by point defects: beyond the perfect 2D world. Nanoscale, 2018, 10, pp 4696-4707 The knowledge on fluorographene reactivity can be used for synthesis of new graphene derivatives, which contain i) mixture of F and other functional groups (like, e.g.
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Radium is not necessary for living organisms, and adverse health effects are likely when it is incorporated into biochemical processes because of its radioactivity and chemical reactivity.
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Even at low temperatures arynes are extremely reactive. Their reactivity can be classified in three main classes: (1) nucleophilic additions, (2) pericyclic reactions, and (3) bond-insertion.
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Piers, W. E., Bourke, S. C. and Conroy, K. D. (2005), Borinium, Borenium, and Boronium Ions: Synthesis, Reactivity, and Applications. Angew. Chem. Int. Ed., 44: 5016–5036.
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Rheumatic fever is a systemic disease affecting the connective tissue around arterioles, and can occur after an untreated strep throat infection, specifically due to group A streptococcus (GAS), Streptococcus pyogenes. It is believed to be caused by antibody cross- reactivity. This cross-reactivity is a type II hypersensitivity reaction and is termed molecular mimicry. Usually, self reactive B cells remain anergic in the periphery without T cell co-stimulation.
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People with confirmed peanut allergy may have cross-reactivity to tree nut, soy, and other legumes, such as peas and lentils and lupinus. The cause of cross-reactivity results from similarity in the structures of storage proteins between the food sources. Allergenic proteins are grouped by protein families: cupins, prolamins, profilin and others. Peanuts and soybeans have proteins in the cupin, prolamin, and profilin families, while lentils contain cupin proteins.
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4-Chloromercuribenzoic acid (p-chloromercuribenzoic acid, PCMB) is an organomercury compound that is used as a protease inhibitor, especially in molecular biology applications. PCMB reacts with thiol groups in proteins and is therefore an inhibitor of enzymes that are dependent on thiol reactivity, including cysteine proteases such as papain and acetylcholinesterase. Because of this reactivity with thiols, PCMB is also used in titrimetric quantification of thiol groups in proteins.
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The flatter flux profile occurs because there are no regions of depressed flux like those that would be produced in the vicinity of inserted control rods. This system is not in widespread use because the chemicals make the moderator temperature reactivity coefficient less negative.DOE Handbook, p. 31. All commercial PWR types operating in the US (Westinghouse, Combustion Engineering, and Babcock & Wilcox) employ soluble boron to control excess reactivity.
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The cysteine sulfhydryl group is nucleophilic and easily oxidized. The reactivity is enhanced when the thiol is ionized, and cysteine residues in proteins have pKa values close to neutrality, so are often in their reactive thiolate form in the cell. Because of its high reactivity, the sulfhydryl group of cysteine has numerous biological functions, and cysteine may have played an important role in the development of primitive life on Earth.
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The central hypothesis of the TN model suggests that for some individuals experiencing psychosis, heightened sensitivity to stress may be mediated by childhood trauma. Alterations in increased stress reactivity are expected to manifest as dysregulation of physiological mechanisms responsible for maintaining adaptive stress responses (i.e., allostasis). This is supported by evidence of analogous irregularities in stress reactivity among individuals diagnosed with schizophrenia and children who have experienced trauma.
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Czosnyka, M., Smielewski, P., Kirkpatrick, P., Laing, R.J., Menon, D. and Pickard, J.D. (1997). Continuous assessment of the cerebral vasomotor reactivity in head injury. Neurosurgery 41, 11-19.
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For example, chitosan modified by methacryloylation exhibits better ability to adhere to mucosal surfaces (mucoadhesion) due to its reactivity with thiols groups present in cysteine domains of mucins ).
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However, reproducibility, cross-reactivity and low repeatability make measurement difficult to be reliable in processed foods. These methods can not discover soybean protein staying in brewed soybean products.
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Despite the constant area under resonance a resonance integral, which determines the absorption, increases with increasing target temperature. This, of course, decreases coefficient k (negative reactivity is inserted).
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The reactivity and uses of TETA are similar to those for the related polyamines ethylenediamine and diethylenetriamine. It is primarily used as a crosslinker ("hardener") in epoxy curing.
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The vaporization of metals is a key step in metal vapor synthesis, which exploits the increased reactivity of metal atoms or small particles relative to the bulk elements.
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In nuclear engineering, the void coefficient (more properly called void coefficient of reactivity) is a number that can be used to estimate how much the reactivity of a nuclear reactor changes as voids (typically steam bubbles) form in the reactor moderator or coolant. Net reactivity in a reactor is the sum total of all these contributions, of which the void coefficient is but one. Reactors in which either the moderator or the coolant is a liquid typically will have a void coefficient value that is either negative (if the reactor is under-moderated) or positive (if the reactor is over-moderated). Reactors in which neither the moderator nor the coolant is a liquid (e.g.
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Composition drift occurs during the process of free radical copolymerization causing variation in the instantaneous mole fraction of a monomer added to copolymer, therefore altering the chemical composition of the copolymer over the period of conversion. The degree of composition drift is directly affected by the reactivity ratios of each monomer in the copolymer system. Both the Mayo-Lewis equation and plot of the equation make evident that as monomer conversion increases, the copolymer composition will drift as the preferences for monomers change due to the interaction between reactivity ratios and the instantaneous concentration of each monomer. Composition drift in some degree will occur unless the reactivity ratios for both monomers are equal to 1.
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The theory of evolution may also explain differences in personality. For example, one of the evolutionary approaches to depression focuses on neuroticism and finds that heightened reactivity to negative outcomes may have had a survival benefit, and that furthermore a positive relationship has been found between neuroticism level and success in university with the precondition that the negative effects of neuroticism are also successfully coped with. Likewise, a heightened reactivity to positive events may have had reproductive advantages, selecting for heightened reactivity generally. Nettle contends that evolution selected for higher levels of neuroticism until the negative effects of neuroticism outweighed its benefits, resulting in selection for a certain optimal level of neuroticism.
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The reactive nature of the cyclic-diester allows good reactivity even for alcohols as hindered as t-butanol. Ketoesters of this type are useful in the Knorr pyrrole synthesis.
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An advantage of this system is that reactivity ratios can be found using tabulated Q-e values of monomers regardless or what the monomer pair is in the system.
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Cycloaddition reaction are not common. Unusual thermal Diels–Alder reactivity of arenes can be found in the Wagner-Jauregg reaction. Other photochemical cycloaddition reactions with alkenes occur through excimers.
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Goodman RE, Wise J. Bioinformatic analysis of proteins in Golden Rice 2 to assess potential allergenic cross-reactivity. Preliminary Report. University of Nebraska. Food Allergy Research and Resource Program.
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The same slowing of the reaction occurs if the pH decreases, because of the protonation of the hydrazine. The reactivity of uracil remains unchanged, even if the temperature changes.
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Geological resistance is a measure of how well minerals resist erosive factors, and is based primarily on hardness, chemical reactivity and cohesion. The more hardness, less reactivity and more cohesion a mineral has, the less susceptible it is to erosion. Over time, differences in geological resistance in the same geological formation can lead to the formation of columns and arches, like those in Moab, Utah; and of bridges, like Utah's Rainbow Bridge.
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The primary method is passive cooling, which requires no mechanical mechanisms to circulate coolant. The reactor design is self-regulating through design geometry that creates a negative temperature reactivity coefficient. In effect this means that as the power demand increases the temperature of the reactor drops. This causes it to shrink, preventing neutrons from leaking out which in turn causes reactivity to increase and power output to increase to meet the demand.
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Assuming the material expands with temperature (enriched uranium-235 at room temperature for example), at an exactly critical state, it will become subcritical if warmed to lower density or become supercritical if cooled to higher density. Such a material is said to have a negative temperature coefficient of reactivity to indicate that its reactivity decreases when its temperature increases. Using such a material as fuel means fission decreases as the fuel temperature increases.
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Noble gases were stripped from the fuel salt by a spray system, reducing the 135Xe poisoning by a factor of about 6. The bulk of the fission product elements remained stable in the salt. Additions of uranium and plutonium to the salt during operation were quick and uneventful, and recovery of uranium by fluorination was efficient. The neutronics, including critical loading, reactivity coefficients, dynamics, and long-term reactivity changes, agreed with prior calculations.
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Differences in reactivity can therefore serve as a footprint of structure along the sequence. Different reagents react at different positions on the RNA structure, and have different spectra of reactivity. Recent advances allow the simultaneous study of the structure of many RNAs (transcriptome-wide probing) and the direct assay of RNA molecules in their cellular environment (in-cell probing). Structured RNA is first reacted with the probing reagents for a given incubation time.
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Several empirical studies have reported differences in sensitivity to the environment in relation to individuals’ physiological reactivity. Higher reactivity generally appears to reflect greater sensitivity. For example, research has shown that children with a higher physiological response to stress (indicated by the hormone cortisol) are more strongly affected by their family’s financial situationObradovic, J., X.A. Portilla, and P.J. Ballard, Biological Sensitivity to Family Income: Differential Effects on Early Executive Functioning. Child Dev, 2016.
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Non-basic tendencies in organocerium reagents The oxophilicity of cerium imparts strong 1,2-selectivity in reactions with conjugated electrophiles similarly to organolithium reagents. At the same time, organocerium reagents can be used to synthesize ketones from acyl compounds without over-addition, as seen with organocuprates. This dichotomy illustrates the unique reactivity of organolanthanide reagents. Reactivity and selectivity of organocerium compounds Finally, organocerium reagents have been employed in a number of total syntheses.
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Reactivity of fullerene molecules with respect to addition chemistries is strongly dependent on the curvature of the carbon framework. Their outer surface (exohedral) reactivity increases with increase in curvature. In comparison with fullerene molecules single-walled nanotubes (SWNTs) are moderately curved. Consequently, nanotubes are expected to be less reactive than most fullerene molecules due to their smaller curvature, but more reactive than a graphene sheet due to pyramidalization and misalignment of pi-orbitals.
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Values for other (n,n) nanotubes show a trend of increasing Өp (sidewall) with decrease in n. Therefore, generally the chemical reactivity of SWNT increases with decrease in diameter (or n, diameter increases with n). Apart from the curvature SWNT reactivity is also highly sensitive to chiral wrapping (n,m) which determine its electronic structure. Nanotubes with n - m = 3i (i is an integer) are all metals and rest are all semiconducting (SC).
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1956, 78, 42. However, their significance is limited more to their existences and structures than to their reactivity. The cyclopentadienyl ligands of f-block metallocenes were considered as inert ancillary ligands, only capable of enhancing their stability and solubility, but not their reactivity. In addition, only late and small metals in the lanthanide series, i.e., elements from Sm to Lu, are trivalent metallocene complexes, [(C5H5)2LnZ]nEvans, W. J.; Wayda, A. L. Inorg. Chem.
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Homoenolates are a type of functional group that have been used in synthetic organic chemistry since the 1980s. They are related to enolates, but represent an umpolung of their reactivity. Homoenolates can be formed with a variety of different metal counterions, including lithium, iron, silver, lead, titanium, tin, tellurium, zirconium, niobium, mercury, zinc, antimony, bismuth, nickel, palladium, and copper. Homoenolates stability and reactivity varies by counterion identity and other nearby functional groups.
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The Fukui function can be utilized in determining the reactivities of molecules towards other molecules. For example, the difference in the Fukui function before and after a CO molecule bonds with a nanoparticle surface can be used to interpret the nanoparticle's reactivity not only with CO but in other core-shell transition metal nanoparticles.Allison, T.C., Tong, Y.J. (2012). Application of the condensed Fukui function to predict reactivity in core–shell transition metal nanoparticles.
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Although many different peroxyacids are used for the Baeyer–Villiger oxidation, some of the more common oxidants include meta-chloroperbenzoic acid (mCPBA) and trifluoroperacetic acid (TFPAA). The general trend is that higher reactivity is correlated with lower pKa (i.e.: stronger acidity) of the corresponding carboxylic acid (or alcohol in the case of the peroxides). Therefore, the reactivity trend shows TFPAA > 4-nitroperbenzoic acid > mCPBA and performic acid > peracetic acid > hydrogen peroxide > tert-butyl hydroperoxide.
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An important reaction for conjugated dienes is the Diels–Alder reaction. Many specialized dienes have been developed to exploit this reactivity for the synthesis of natural products (e.g., Danishefsky's diene).
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Further radical modes of reactivity include radical substitutions on weak C-H bonds to form α‐azido ethers, benzal acetals, and aldehydes, and the conversion of aldehydes to acyl azides.
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Version 6.1. ORNL/TM-2005/39 It can be thought of as a "milli-percent". It is commonly used in epidemiology, and nuclear reactor engineering as a unit of reactivity.
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Part of the research focused on specific thematic areas of cement research including hydrate assemblages, pore structure, rheology, reactivity (chemistry), durability and mechanical properties, production, environmental sustainability, and cost effectiveness.
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The phenomenon of heavy reactivity received wide popularity. The event was described by scientific journals, including La Recherche Nr. 159, Oct. 1984 p. 1300; Science et Vie Nr. 808, Jan.
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One of the simplest methods for finding reactivity ratios is plotting the copolymer equation and using least squares analysis to find the r_1\,, r_2\, pair that gives the best fit curve.
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Acetic anhydride is an irritant and combustible liquid. Because of its reactivity toward water, alcohol foam or carbon dioxide are preferred for fire suppression. The vapour of acetic anhydride is harmful.
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The test for cyanide relies on similar reactivity. Such applications have largely been replaced by methods using phenolphthalein/hydrogen peroxide and luminol. The popular dye congo red is derived from benzidine.
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The molecule displays reactivity reminiscent of diborane.Keister, J. B.; Shapley, J. R. “Solution Structures and Dynamics of complexes of Decacarbonyldihydrotriosmium with Lewis Bases” Inorganic Chemistry 1982, volume 21, pages 3304–3310; .
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Dyed and polished magnesite beads Salem Similar to the production of lime, magnesite can be burned in the presence of charcoal to produce MgO, which, in the form of a mineral, is known as periclase. Large quantities of magnesite are burnt to make magnesium oxide: an important refractory material used as a lining in blast furnaces, kilns and incinerators. Calcination temperatures determine the reactivity of resulting oxide products and the classifications of light burnt and dead burnt refer to the surface area and resulting reactivity of the product, typically as determined by an industry metric of the iodine number. 'Light burnt' product generally refers to calcination commencing at 450 °C and proceeding to an upper limit of 900 °C – which results in good surface area and reactivity.
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A meta-analysis of 41 cue reactivity studies with people that have an alcohol, heroin, or cocaine addiction strongly supports the finding that people who have addictions have significant cue-specific reactions to drug-related stimuli. In general, these individuals, regardless of drug of abuse, report robust increases in craving and exhibit modest changes in autonomic responses, such as increases in heart rate and skin conductance and decreases in skin temperature, when exposed to drug-related versus neutral stimuli. Surprisingly, despite their obvious clinical relevance, drug use or drug- seeking behaviors are seldom measured in cue reactivity studies. However, when drug-use measures are used in cue reactivity studies the typical finding is a modest increase in drug-seeking or drug-use behavior.
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Chain growth polycondensation polymerizations were initially developed under the premise that a change in substituent effects of the polymer, relative to the monomer, causes the polymers end group to be more reactive this has been referred to as "reactive intermediate polycondensation". The essential result is monomers preferentially react with the activated polymer end groups over reactions with other monomers. This preferred reactivity is the fundamental difference when categorizing a polymerization mechanism as chain-growth as opposed to step-growth in which the monomer and polymer chain end group have equal reactivity (the reactivity is uncontrolled). Several strategies were employed to minimize monomer-monomer reactions (or self-condensation) and polymerizations with low D and controllable Mn have been attained by this mechanism for small molecular weight polymers.
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A later paper by Edwards and Pearson, following research done by Jencks and Carriuolo in 1960 led to the discovery of an additional factor in nucleophilic reactivity, which Edwards and Pearson called the alpha effect, where nucleophiles with a lone pair of electrons on an atom adjacent to the nucleophilic center have enhanced reactivity. The alpha effect, basicity, and polarizability are still accepted as the main factors in determining nucleophilic reactivity. As such, the Edwards equation is applied in a qualitative sense much more frequently than in a quantitative one. In studying nucleophilic reactions, Edwards and Pearson noticed that for certain classes of nucleophiles most of the contribution of nucleophilic character originated from their basicity, resulting in large β values.
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Commonly used oxygen carriers are based on NiO or Fe2O3. The NiO-based oxygen carriers exhibit excellent reactivity, as shown by the high conversion of natural gas. The Fe2O3-based oxygen carriers have a lower material cost while their reactivity is lower than that of the NiO-based ones. Operating variables such as temperature, pressure, type of metal oxide, and molar ratio of metal oxide to gaseous fuel will influence the fuel conversion and product compositions.
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The mechanical bond can reduce the kinetic reactivity of the products, this is ascribed to the increased steric hindrance. Because of this effect hydrogenation of an alkene on the thread of a rotaxane is significantly slower as compared to the equivalent non interlocked thread. This effect has allowed for the isolation of otherwise reactive intermediates. The ability to alter reactivity without altering covalent structure has led to MIMAs being investigated for a number of technological applications.
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Room temperature treatment of SLGO with carbodiimides leads to the collapse of the individual sheets into star-like clusters that exhibited poor subsequent reactivity with amines (c. 3–5% conversion of the intermediate to the final amide). It is apparent that conventional chemical treatment of carboxylic groups on SLGO generates morphological changes of individual sheets that leads to a reduction in chemical reactivity, which may potentially limit their use in composite synthesis. Therefore, chemical reactions types have been explored.
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Many modifications have been reported that influence the reactivity of this reagent. The compound adopts a complex cluster structure (the adjacent picture is a simplified cartoon), and additives that modify the cluster affect the reactivity of the reagent. For example, DMF, DMSO, hexamethylphosphoramide (HMPA), and 18-crown-6 interact with the potassium center, enhancing the basicity of the butoxide. Schlosser's base, a mixture of the alkoxide and an alkyl lithium compound, is a related but stronger base.
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If the boron concentration is increased, the coolant/moderator absorbs more neutrons, adding negative reactivity. If the boron concentration is reduced (dilution), positive reactivity is added. The changing of boron concentration in a PWR is a slow process and is used primarily to compensate for fuel burnout or poison buildup. The variation in boron concentration allows control rod use to be minimized, which results in a flatter flux profile over the core than can be produced by rod insertion.
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In chemistry, a phosphaalkyne (IUPAC name: alkylidynephosphane) is an organophosphorus compound containing a triple bond between phosphorus and carbon with the general formula R-C≡P. Phosphaalkynes are the heavier congeners of nitriles, though, due to the similar electronegativities of phosphorus and carbon, possess reactivity patterns reminiscent of alkynes. Due to their high reactivity, phosphaalkynes are not found naturally on earth, but the simplest phosphaalkyne, phosphaethyne (H-C≡P) has been observed in the interstellar medium.
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Their atmospheric concentrations and contribution to anthropogenic greenhouse gas emissions are rapidly increasing, causing international concern about their radiative forcing. Fluorocarbons with few C–F bonds behave similarly to the parent hydrocarbons, but their reactivity can be altered significantly. For example, both uracil and 5-fluorouracil are colourless, high-melting crystalline solids, but the latter is a potent anti-cancer drug. The use of the C-F bond in pharmaceuticals is predicated on this altered reactivity.
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OND-2,3-dicarboxylates (thereafter referred to as OND) display unusually high reactivity towards azides and thiols. OND–thiol adducts are prone to retro-Diels–Alder fragmentation, which occurs with widely variable rates.
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Fluorine is the thirteenth most common element in Earth's crust, comprising between 600 and 700 ppm of the crust by mass. Because of its reactivity, it is essentially only found in compounds.
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The reactivity of H2 is strongly affected by the presence of metal catalysts. Thus, while H2 combusts readily, mixtures of H2 and O2 do not react in the absence of a catalyst.
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Overall positive emotions help lower the potentially health-damaging cardiovascular reactivity that lingers following negative emotions. This effect may be especially important for those most at risk for developing coronary heart disease.
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The structure can also form a π complex with lithium cations, which affects the cycloaddition reactivity. It can even interact strongly enough with copper species to form a novel type of metallacycle.
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Pupillometry, the measurement of pupil size and reactivity, is a key part of the clinical neurological exam for patients with a wide variety of neurological injuries. It is also used in psychology.
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The reactivity of a methyl group depends on the adjacent substituents. Methyl groups can be quite unreactive. For example, in organic compounds, the methyl group resists attack by even the strongest acids.
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Despite its high reactivity as an alkylating agent, and unlike analogue β-lactones propiolactone and β-butyrolactone, diketene is inactive as a carcinogen, possibly due to the instability of its DNA adducts.
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Many nanoparticles exhibit toxic effects throughout the body due to their size and reactivity. These effects would only be amplified in the vulnerable neurons within the brain, causing more damage than they repair.
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Colorless, odorless, non-flammable gases with very low chemical reactivity. The first noble gas compound, of approximate composition XePtF6, was not prepared until 1962; compounds of He and Ne are as yet unknown.
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Similarly, the capabilities of the ion-trap mass spectrometer are used to elucidate the structure, determine the relative stability, and probe the general patterns in chemical reactivity of gas-phase metal ion complexes.
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Because the A-value of tert-butyl is higher, tert-butyl has a larger steric effect than methyl. This difference in steric effects can be used to help predict reactivity in chemical reactions.
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Reactivity is tested using oral food challenges or with skin prick tests. Phases 1 & 2 of sublingual immunotherapy are conducted in a supervised clinical setting. However, phase 3 can be done at home.
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Mutagenicities of styrene oxide derivatives on bacterial test systems: relationship between mutagenic potencies and chemical reactivity. Chemico-Biological Interactions, 35(1), 71-91. There are often tumors observed at the site of exposure.
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Quiescent affinity labels represent a promising approach for inhibiting enzymes using ‘masked’ reactive functionalities that are only uncovered within the active site. This approach differs from mechanism-based inactivators in that the catalysis must be "off-pathway". One of the best examples to explain this form of catalysis is in the inactivation dimethylargine dimethylaminohydrolase (DDAH) by 4-halopyridines. At physiological pH, the 4-halo group has near negligible reactivity with thiolates but upon protonation of the nitrogen, the reactivity increases ~4500-fold.
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When the coolant water temperature increases, the boiling increases, which creates voids. Thus there is less water to absorb thermal neutrons that have already been slowed by the graphite moderator, causing an increase in reactivity. This property is called the void coefficient of reactivity, and in an RBMK reactor like Chernobyl, the void coefficient is positive, and fairly large, causing rapid transients. This design characteristic of the RBMK reactor is generally seen as one of several causes of the Chernobyl disaster.
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Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in virtually all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection is a critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemistry.
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Thus, in the case of LiHMDS, TMEDA does not increase reactivity by reducing aggregation state. Also, as opposed to simple alkyllithium compounds, TMEDA does not deaggregate lithio-acetophenolate in THF solution. The addition of HMPA to lithium amides such as LiHMDS and LDA often results in a mixture of dimer/monomer aggregates in THF. However, the ratio of dimer/monomer species does not change with increased concentration of HMPA, thus, the observed increase in reactivity is not the result of deaggregation.
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IV., W. Foerst, Ed., Academic Press, New York, 1968, pp. 163–335. These two reagents are on the extremes of reactivity—whereas lithium aluminium hydride reacts with nearly all reducible functional groups, sodium borohydride reacts with a much more limited range of functional groups. Diminished or enhanced reactivity may be realized by the replacement of one or more of the hydrogens in these reagents with alkoxy groups. Additionally, substitution of hydrogen for chiral alkoxy groups in these reagents enables asymmetric reductions.
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1,3 dipolar cycloadditions have been developed as a bioorthogonal reaction using a nitrile oxide as a 1,3-dipole and a norbornene as a dipolarophile. Its primary use has been in labeling DNA and RNA in automated oligonucleotide synthesizers. Cycloaddition between a norbornene and a nitrile oxide Norbornenes were selected as dipolarophiles due to their balance between strain-promoted reactivity and stability. The drawbacks of this reaction include the cross- reactivity of the nitrile oxide due to strong electrophilicity and slow reaction kinetics.
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Besides the well recognized problems associated with large volume expansion, for example cracking the SEI layer, a second well recognized issues involves the reactivity of the charged materials. Since charged silicon is a lithium silicide, its salt-like structure is built from a combination of silicon (-4) Zintl anions and lithium cations. These silicide anions are highly reduced and display high reactivity with the electrolyte components that is charge compensated locally by reduction of the solvents. Recent work by Han, et al.
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Reactor power is controlled by the amount of heat removed from the reactor: increased heat removal results in a drop in fuel salt temperature, resulting in increased reactivity and in turn increased power. Conversely, reducing heat removal will increase reactor temperature at first, lowering reactivity and subsequently reducing reactor power. If all heat removal is lost, the reactor power will drop to a very low power level. As backup (and shutdown method for maintenance), the IMSR employs shutdown rods filled with neutron absorber.
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When Sm(III) is complexed with (pentamethylcyclopentadiene) to give the compound , this trivalent species has been shown to have the same reducing reactivity of the Sm(II) derivative.Evans, William J. The Expansion of Divalent Organolanthanide Reduction Chemistry Via New Molecular Divalent Complexes and Sterically Induced Reduction Reactivity of Trivalent Complexes. Journal of Organometallic Chemistry 647 (2002) 2-11. Sm+2 vs Sm+3 Reductions The top reaction is the Sm(III) derivative and the bottom involves the Sm(II) derivative.
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Soluble poisons, also called chemical shim, produce a spatially uniform neutron absorption when dissolved in the water coolant. The most common soluble poison in commercial pressurized water reactors (PWR) is boric acid, which is often referred to as soluble boron. The boric acid in the coolant decreases the thermal utilization factor, causing a decrease in reactivity. By varying the concentration of boric acid in the coolant, a process referred to as boration and dilution, the reactivity of the core can be easily varied.
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This heightened reactivity has many practical consequences. The industrial production of acrylonitrile by ammoxidation of propene exploits the easy oxidation of the allylic C−H centers: :2CH3−CH=CH2 \+ 2NH3 \+ 3O2 → 2CH2=CH−C≡N + 6H2O Unsaturated fats spoil by rancidification involving attack at allylic C−H centers. Benzylic and allylic are related in terms of structure, bond strength, and reactivity. Other reactions that tend to occur with allylic compounds are allylic oxidations, ene reactions, and the Tsuji–Trost reaction.
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Recently, the interest in this reaction pathway was revived by Piers et al.., who studied the reactivity of perfluorinated [PhBC4Ph4] (2 in the figure above) towards alkynes in great detail. Of particular relevance was the question of whether the enhanced Lewis acidity of 2 compared 1 affects its reactivity and whether that entails novel reactivity patterns. In that study, 2 was reacted with three differently substituted alkynes that greatly differed in their electronic properties, namely (C6F5)CC(C6F5), (C6H5)CC(C6H5) and Et–CC–Et. The reaction with the electron-poor alkyne (C6F5)CC(C6F5) required rather harsh reaction conditions (110 °C, 7 days) and the only observable species was the expected Diels–Alder product (3), whose formation presumably follows a mechanism similar to that proposed for 5.
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Other means of controlling reactivity include (for PWR) a soluble neutron absorber (boric acid) added to the reactor coolant, allowing the complete extraction of the control rods during stationary power operation, ensuring an even power and flux distribution over the entire core. This chemical shim, along with the use of burnable neutron poisons within the fuel pellets, is used to assist regulation of the core's long term reactivity, while the control rods are used for rapid reactor power changes (e.g. shutdown and start up). Operators of BWRs use the coolant flow through the core to control reactivity by varying the speed of the reactor recirculation pumps (an increase in coolant flow through the core improves the removal of steam bubbles, thus increasing the density of the coolant/moderator, increasing power).
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Professor Klopman’s work has involved the evaluation of chemical reactivity and includes experimental determination of reactivity indices and substituent constants to the development of reactivity theories . He has contributed significantly to the concept of charge and orbital controlled reactions where his work is widely used to explain the ambident selectivity of nucleophiles and links the linear free energy type correlations to more fundamental chemical concepts. In the field of quantum mechanics and computers he has designed and programmed the first semi-empirical method for the calculation of the properties of saturated molecules that later became known as MINDO. His work also encompasses problems of artificial intelligence and its general use to correlate biological data and he has been involved in developing software to represent and manipulate chemical data.
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Autoantibodies can sometimes errantly be directed against healthy portions of the organism, causing autoimmune diseases. ATA can be classified according to 2 different schemes: transglutaminase isoform and immunoglobulin reactivity subclass (IgA, IgG) toward transglutaminases.
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Polishing refers to treatments made following the above methods. These treatments may also be used independently for some industrial wastewater. Chemical reduction or pH adjustment minimizes chemical reactivity of wastewater following chemical oxidation.Weber, p.
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The structure of iproniazid is chemically, in both structure and reactivity, similar to isoniazid. Iproniazid is a substituted hydrazine of which the isopropyl hydrazine moiety is essential for the inhibition of monoamine oxidase activity.
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A particularly powerful qualitative approach to assessing the structure and reactivity begins with classifying molecules according to electron counting, focusing on the numbers of valence electrons, usually at the central atom in a molecule.
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Unlike in cyclopropane, the C–C bond lengths actually increase rather than decrease; this is mainly due to 1,3-nonbonded steric repulsion. In terms of reactivity, cyclobutane is relatively inert and behaves like ordinary alkanes.
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Biginelli's first known scientific work, in which he was a co-author to his mentor Icilio Guareschi, was focused on synthesis and reactivity of chlorobromonaphtalene.J. Chem. Soc., Abstr., 1887, vol. 52, pp. 1088–1127Chem. Zentr.
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Rheumatic fever is a systemic disease affecting the peri-arteriolar connective tissue and can occur after an untreated Group A Beta-hemolytic streptococcal pharyngeal infection. It is believed to be caused by antibody cross-reactivity.
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The phosphorus in PCl3 is often considered to have the +3 oxidation state and the chlorine atoms are considered to be in the −1 oxidation state. Most of its reactivity is consistent with this description.
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Also, it was found to have a reactivity lower than pyrite, but distinctly higher than bornite.Kajiwara, Yoshimichi. "Fukuchilite, Cu3FeS8, a New Mineral From the Hanawa Mine, Akita Prefecture, Japan." Mineralogical Journal 5 (1969): 400-415.
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Unlike benzene, C6H6, cyclooctatetraene, C8H8, is not aromatic, although its dianion, (cyclooctatetraenide), is. Its reactivity is characteristic of an ordinary polyene, i.e. it undergoes addition reactions. Benzene, by contrast, characteristically undergoes substitution reactions, not additions.
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Directing effect of an –OH group on diastereoselectivity of hydrogenation by Crabtree's catalyst. Hydrogen is added from the direction of the iridium atom, selecting for the reactivity shown above. Additional ligands on catalyst not shown.
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While with typical CANDU derived fuel bundles, the reactor design has a slightly positive Void coefficient of reactivity, the Argentina designed CARA fuel bundles used in Atucha I, are capable of the preferred negative coefficient.
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Thus, a full and uninterrupted 7-hour sleep is crucial for the proper functioning of the amygdala in modulating an individual's mood states by reducing negative emotional intensities and increasing reactivity to positive emotional stimuli.
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When heated, Fe(CO)5 converts to small amounts of the metal cluster Fe3(CO)12, a green solid. Simple thermolysis, however, is not a useful synthesis, and each iron carbonyl complex exhibits distinct reactivity.
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The acute oral median lethal dose in rats is very low at over 5000 mg/kg due to the compound's reactivity with thiols. This reactivity can have negative consequences since repeated exposure can cause skin sensitization and dermatitis to develop in some individuals. Fluazinam also displays low toxicity to birds, bees and worms, but has a high toxicity to fish. The toxicity towards fish is considered to be relatively unimportant, since the compound has a very short half-life (around 1 day) in aquatic systems.
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Overall reactivity potential for different hardeners can roughly be ordered; aliphatic amines > cycloaliphatic amines > aromatic amines, though aliphatic amines with steric hindrance near the amino groups may react as slowly as some of the aromatic amines. Slower reactivity allows longer working times for processors. Temperature resistance generally increases in the same order, since aromatic amines form much more rigid structures than aliphatic amines. Aromatic amines were widely used as epoxy resin hardeners, due to the excellent end properties when mixed with a parent resin.
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Individuals with social anhedonia may display increased stress reactivity, meaning that they feel more overwhelmed or helpless in response to a stressful event compared to control subjects who experience the same type of stressor. This dysfunctional stress reactivity may correlate with hedonic capacity, providing a potential explanation for the increased anxiety symptoms experienced in people with social anhedonia. In an attempt to separate out social anhedonia from social anxiety, the Revised Social Anhedonia ScaleEckblad, M.L., Chapman, L.J., Chapman, J.P., & Mishlove, M. (1982). The Revised Social Anhedonia Scale .
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Three genotypes (genetic strains) have been identified in the breed: Heterozygous for (carrying but not expressing) the gene, and homozygous either for (expressing) the gene, or not possessing it at all. The heterozygous has an intermediate carcass and meat quality and a selection advantage. The homozygous for reactivity to halothane had lowest meat quality, though highest meat production of the three genotypes, and as noted in the first study, its high reactivity level can be used for screening. It also has the lowest percentage loss at slaughter.
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A novel protein is a protein source used in hypoallergenic diets to which the cat has not previously been exposed. Common examples of novel proteins are lamb, rabbit, venison, duck, elk, kangaroo, ostrich, emu, goose and goat. However, there is a chance of cross-reactivity when there is a higher taxonomic relationship between the two species. For example, cross-reactivity could be caused by other ruminant meats if the cat reacted negatively to beef, or avian meats if the cat reacted negatively to chicken.
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When all control rods are fully inserted, they keep reactivity barely above 0, which quickly slows a running reactor to a stop and keeps it stopped (in shutdown). If all control rods are fully removed, reactivity is significantly above 1, and the reactor quickly runs hotter and hotter, until some other factor slows the reaction rate. Maintaining a constant power output requires keeping the long- term average neutron multiplication factor close to 1. A new reactor is assembled with its control rods fully inserted.
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The highest quality liver of sulfur in solid form is a dark yellow, almost "liver" colored substance. As it ages and is exposed to air, its potency decreases, it will turn lighter yellow and finally white, at which point its reactivity is negligible. Liver of sulfur decomposes to sulfate of potash and carbonate of potash, neither of which has any value as an oxidizer of metal. The reactivity of liver of sulfur with silver and copper quickly creates a dark or colored patina on the metal.
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Heavy water remains in the low-pressure section of the calandria, where it is essentially static and used only as a moderator. The reactivity regulating and safety devices are located within the low-pressure moderator. The ACR also incorporates characteristics of the CANDU design, including on-power refueling with the CANFLEX fuel; a long prompt neutron lifetime; small reactivity holdup; two fast, independent, safety shutdown systems; and an emergency core cooling system. The fuel bundle is a variant of the 43-element CANFLEX design (CANFLEX-ACR).
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The structure, properties, and reactivity of a molecule are dependent on straightforward bonding interactions including covalent bonds, ionic bonds, hydrogen bonds, and other forms of bonding. This bonding supplies a basic molecular skeleton that is modified by repulsive forces generally considered steric effects. Basic bonding and steric effects are at times insufficient to explain many structures, properties, and reactivity. Thus, steric effects are often contrasted and complemented by electronic effects, implying the influence of effects such as induction, conjunction, orbital symmetry, electrostatic interactions, and spin state.
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It is suggested through DFT calculations that the 5–exo–dig cyclization is favored for Au(I) complexes as it has a lower activation barrier relative to the 6–endo–dig and indeed numerous examples of vinylcycloalkenes products produced via an initial 5–exo–dig are given (figure 11). center The reactivity can be reversed by careful selection of reaction conditions, catalyst selection and substrate. The divergent reactivity of these transition metal catalyzed cyclosiomerizations further demonstrates their synthetic utility in building unique molecular skeletons.
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It is also larger than silylamides. For these reasons, silox anion forms highly unsaturated complexes. Complexes with high coordinative unsaturation display high reactivity so long as they do not undergo intramolecular reactions. Silox offers this possibility.
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Research in the Organic Synthesis Department, led by Tobias Ritter, focuses on the development of novel reaction chemistry. It seeks to discover molecular structure and reactivity that can contribute to interdisciplinary solutions for challenges in science.
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By coupling liquid chromatography with a variety of other immunodetection techniques such as serological proteome analysis (SERPA), it is possible to analyze the hydrophobicity, PI, relative mass, and antibody reactivity of antibodies within a given serum.
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The use of LEU fuel with a neutron absorbing centre element allows the reduction of coolant void reactivity coefficient to a nominally small, negative value. It also results in higher burnup operation than traditional CANDU designs.
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Silicon tetrachloride is a classic electrophile in its reactivity. It forms a variety of organosilicon compounds upon treatment with Grignard reagents and organolithium compounds: :4 RLi + SiCl4 → R4Si + 4 LiCl Reduction with hydride reagents afford silane.
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Sesquiterpenoid unsaturated dialdehydes. Structural properties that affect reactivity and bioactivity. PhD Thesis, Lund (Sweden). An ex vivo study used a horopito and aniseed mixture (Kolorex) to inhibit the growth of C. albicans in the oral cavity.
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Only occasionally have these food-induced allergies induced systemic responses. Researchers suspect that the cross-reactivity of latex with banana, avocado, kiwifruit, and chestnut occurs because latex proteins are structurally homologous with some other plant proteins.
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A ball-and-stick model of polypropylene. Prolene is a synthetic, monofilament, nonabsorbable polypropylene suture. It is indicated for skin closure and general soft tissue approximation and ligation. Its advantages include minimal tissue reactivity and durability.
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Objects in low Earth orbit are subjected to noticeable erosion from atomic oxygen due to the high orbital speed with which the molecules strike as well as their high reactivity. This could quickly erode a tether.
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The peroxides are much less reactive than the peroxyacids. The use of hydrogen peroxide even requires a catalyst. In addition, using organic peroxides and hydrogen peroxide tends to generate more side-reactivity due to their promiscuity.
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A spectator ligand is a tightly coordinating polydentate ligand that does not participate in chemical reactions but removes active sites on a metal. Spectator ligands influence the reactivity of the metal center to which they are bound.
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The ability for a mechanical bond to reduce reactivity and hence prevent unwanted reactions has been exploited in a number of areas. One of the earliest applications was in the protection of organic dyes from environmental degradation.
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Like most alkanes, hexane characteristically exhibits low reactivity and are suitable solvents for reactive compounds. Commercial samples of n-hexane however often contains methylcyclopentane, which features tertiary C-H bonds, which are incompatible with some radical reactions.
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Littlejohn received her PhD from the University of Strathclyde in Chemistry in 1988. Her thesis was titled A Comparative Examination of the Mechanical Properties of Sodium Nitrate and Calcite and the Influence of Defects On Their Reactivity.
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Molecular electrochemistry of coordination and organic compounds, namely towards applications in electrosynthesis, electrocatalysis and in mechanistic studies, as well as in the establishment of potential-structure relationships, and in the induction of chemical reactivity by electron- transfer.
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In seawater, glutathione reacts with citrate to form a thioester via esterification.Sidenius U, Skonberg C, Olsen J, Hansen S (2003). In vitro reactivity of carboxylic acid-CoA thioesters with glutathione. Chemical Research in Toxicology, 17: 75-81.
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Water is used as a coolant, but not a moderator. If the water boils away, cooling is lost, but moderation continues. This is termed a positive void coefficient of reactivity. The RBMK tends towards dangerous power fluctuations.
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Common adverse drug reactions are nausea and vomiting. People who are allergic to penicillin and other β-lactam antibiotics should take caution if taking imipenem, as cross-reactivity rates are high. At high doses, imipenem is seizurogenic.
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The vast majority of important organic molecules contain heteroatoms, which polarize carbon skeletons by virtue of their electronegativity. Therefore, in standard organic reactions, the majority of new bonds are formed between atoms of opposite polarity. This can be considered to be the "normal" mode of reactivity. One consequence of this natural polarization of molecules is that 1,3- and 1,5- heteroatom substituted carbon skeletons are extremely easy to synthesize (Aldol reaction, Claisen condensation, Michael reaction, Claisen rearrangement, Diels-Alder reaction), whereas 1,2-, 1,4-, and 1,6- heteroatom substitution patterns are more difficult to access via "normal" reactivity.
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New York: McGraw-Hill. . p. 234. does not imply a hydrogen ion concentration of 1021 mol/dm3: such a "solution" would have a density more than a hundred times greater than a neutron star. Rather, H0 = −21 implies that the reactivity (protonating power) of the solvated hydrogen ions is 1021 times greater than the reactivity of the hydrated hydrogen ions in an aqueous solution of pH 0\. The actual reactive species are different in the two cases, but both can be considered to be sources of H+, i.e.
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In Hückel theory, a Dewar reactivity number, also known as Dewar number, is a measure of the reactivity in aromatic systems. It is used to quantify the difference in energy between the π-system of the original molecule and the intermediate having the incoming electrophile or nucleophile attached. It can be used to study important transformations such as the nitration of conjugated systems from a theoretical perspective. The change in energy during the reaction can be derived by allowing the orbitals nearby the site i of attack to interact with the incoming molecule.
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Due to the high steric demand of the TMP ligand and its flexible rotation in solution, the THF molecule gets separated from the magnesium cation. The result is an unsaturated magnesium side that could explain the enhanced reactivity and selectivity of TMPMgCl·LiCl. TMP-Turbo- Hauser Base in THF solution Knochel et al. proposed that LiCl increases the reactivity of Turbo-Grignard compounds RMgCl·LiCl (R = alkyl, aryl or vinyl) by giving the reactive bimetallic monomer a magnesiate character in sense of a solvent separated ion pair (SSIP) [Li(THF)4]+ [RMg(THF)Cl2]−.
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Similar to HIV-1, gpD also aids in binding to chemokines on the cell surface of the host to gain entry into the host. Cross- reactivity of the self epitope (α-subunit of the receptor) with antibodies produced against HSV suggests that the virus is associated with the initiation of myasthenia gravis. Not only does HSV cause immunologic cross-reactivity, but the gpD peptide also competitively inhibits the binding of antibody made against the α-subunit to its corresponding peptide on the α-subunit. Despite this, an autoimmune response still occurs.
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Multiwell plates are used initially to grow the hybridomas, and after selection, are changed to larger tissue culture flasks. This maintains the well-being of the hybridomas and provides enough cells for cryopreservation and supernatant for subsequent investigations. The culture supernatant can yield 1 to 60 μg/ml of monoclonal antibody, which is maintained at -20 °C or lower until required. By using culture supernatant or a purified immunoglobulin preparation, further analysis of a potential monoclonal antibody producing hybridoma can be made in terms of reactivity, specificity, and cross-reactivity.
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Her dissertation work focused on investigating molecular-level surface reactivity and kinetics of metal surfaces using electron spectroscopy, laser desorption, and Fourier transform mass spectrometry techniques. She also designed and built peripheral components for a variable temperature, ultra- high vacuum scanning tunneling microscopy system. In 1997, Caldwell Dyson received the Camille and Henry Drefus Postdoctoral Fellowship in Environmental Science to study atmospheric chemistry at the University of California, Irvine. There she investigated reactivity and kinetics of atmospherically relevant systems using atmospheric pressure ionization mass spectrometry, Fourier transform infrared and ultraviolet absorption spectroscopies.
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With its three different reactive centers—nitrile, ester, acidic methylene site—ethyl cyanoacetate is a versatile synthetic building block for a variety of functional and pharmacologically active substances. It contains an acidic methylene group, flanked by both the nitrile and carbonyl, and so can be used in condensation reactions like the Knoevenagel condensation or the Michael addition. This reactivity is similar to that of esters of malonic acid. As an example of reactivity at the nitrile, diethyl malonate is obtained from cyanoacetic acid ethyl ester by reaction with ethanol in the presence of strong acids.
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She probed how diet effects immune infiltration into the brain since previous studies had showed that it might lead to compromised blood brain barrier function and increased immune cell infiltration into the CNS. Conversely, her findings showed that high fat high fructose diets did not increase peripheral trafficking of immune cells into the CNS. Tansey also explored the sex-specific effects of stress on neuro-immune reactivity and found that early life chronic stress led to increased neuro-immune reactivity but via different mechanisms in male versus female rats.
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However, when these genes were deleted in the forebrain or during adulthood, there was no somatosensory over-reactivity. When MeCP2 was selectively expressed in only the peripheral sensory neurons, this was enough to restore defects in touch sensitivity, social behavior, and anxiety. Overall, her findings pointing to the periphery as the site at which these ASD mutations exert their influence on sensory over-reactivity and its contribution to ASD phenotypes. Orefice followed these findings to explore the possibility of targeting the peripheral somatosensory neurons therapeutically in ASD models.
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In analyzing PRBs, emphasis has been placed on losses of reactivity and permeability in the reactive well; however, flawed hydraulic characterization of the few PRB failures that have been reported. Oxidation- reduction potential, influent [pH], and influent concentrations of [alkalinity], [nitrate ], and [chloride Cl−] are the strongest predictors of possible diminished performance of PRBs. The reactivity of the media, rather than a reduction in permeability is more likely the factor that limits field PRB longevity. Because this technology is relatively new, it is still hard to predict the longevity of sites.
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N-bromosuccinimide, a common brominating reagent in organic chemistry Like the other carbon–halogen bonds, the C–Br bond is a common functional group that forms part of core organic chemistry. Formally, compounds with this functional group may be considered organic derivatives of the bromide anion. Due to the difference of electronegativity between bromine (2.96) and carbon (2.55), the carbon in a C–Br bond is electron-deficient and thus electrophilic. The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds.
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For some types of particles, the smaller they are, the greater their surface area to volume ratio and the higher their chemical reactivity and biological activity. The greater chemical reactivity of nanomaterials can result in increased production of reactive oxygen species (ROS), including free radicals. ROS production has been found in a diverse range of nanomaterials including carbon fullerenes, carbon nanotubes and nanoparticle metal oxides. ROS and free radical production is one of the primary mechanisms of nanoparticle toxicity; it may result in oxidative stress, inflammation, and consequent damage to proteins, membranes and DNA.
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Chlorine-releasing bleaches and disinfectants depend on the strong reactivity of chlorine towards many organic compounds; in particular, its strong oxidizing character, that is, its strong affinity for electrons. It readily inserts itself into double bonds, including those of aromatic rings, creating chlorinated organic compound. This accounts for its bleaching action, since many colored organic substances owe their color to compounds with such bonds. The extensive reactivity of chlorine is also responsible for its broad antimicrobial effect, since it can destroy or denature many proteins and other chemicals that are essential for microbes' metabolism.
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Cyanazine can decompose on heating. This produces corrosive fumes of hydrogen chloride, nitrogen oxides and cyanides.ILO and WHO, 1999; International safety card Cyanazine. Cyanazine has one of the lowest rate constant of reactivity with ozone from different pesticides.
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Hadfield, J. A.; Pavlidis, V. H.; Perry, P. J.; McGown, A. T. Anti-Cancer Drugs. 1999, 10 (6), 591-595 Furthermore, structural features of 2-iminopyrane cycle cause unusual reactivity of these compounds.O'Callaghan C.N. Proc. R. Ir. Acad.
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Fluorine is relatively rare in the universe compared to other elements of nearby atomic weight. On earth, fluorine is essentially found only in mineral compounds because of its reactivity. The main commercial source, fluorite, is a common mineral.
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Synthesis, properties, and reactivity of the compound were first described in 2006 by Antonio Togni and his coworkers at ETH Zurich. The article also contains information on 1,3-Dihydro-3,3-dimethyl-1-(trifluoromethyl)-1,2-benziodoxole (Togni Reagent I).
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Chloramine-T contains active (electrophilic) chlorine. Its reactivity is similar to that of sodium hypochlorite. Aqueous solutions of chloramine-T are slightly basic (pH typically 8.5). The pKa of the closely related N-chlorophenylsulfonamide C6H5SO2NCl(H) is 9.5.
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Dipolar compounds can be represented by a resonance structure. Contributing structures containing charged atoms are denoted as zwitterions. Braida et al.: A clear correlation between the diradical character of 1,3-dipoles and their reactivity toward ethylene or acetylene.
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There is also possibility of anti-cardiac antibodies created idiopathically, or due to concurrent cross-reactivity of the antibodies produced against viral antigens, however the latter assumption is not fool-proof or completely reliable due to conflicting studies.
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Tilley’s research group conducts exploratory synthetic, structural, and reactivity studies of inorganic and organometallic systems. His research program includes: organometallic chemistry and homogenous catalysis, materials chemistry and heterogenous catalysis, organic electronic materials, supramolecular chemistry, and solar energy conversion.
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Individuals with active tuberculosis were usually tuberculin positive, but many of those with disseminated and rapidly progressive disease were negative. This led to the widespread, but erroneous belief, that tuberculin reactivity is an indicator of immunity to tuberculosis.
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The chemistry of maleic anhydride is very rich, reflecting its ready availability and bifunctional reactivity. It hydrolyzes, producing maleic acid, cis-HOOC-CH=CH-COOH. With alcohols, the half-ester is generated, e.g., cis-HOOC-CH=CH-COOCH3.
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Bismuth oxide is considered a basic oxide, which explains the high reactivity with CO2. However, when acidic cations such as Si(IV) are introduced within the structure of the bismuth oxide, the reaction with CO2 do not occur.
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Dimethylphosphite is an organophosphorus compound with the formula (CH3O)2P(O)H. It is a reagent for generating other organophosphorus compounds, exploiting the high reactivity of the P-H bond. The molecule is tetrahedral. It is a colorless liquid.
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Dalbavancin is contraindicated in patients with hypersensitivity to dalbavancin, such as skin reactions or anaphylaxis, and caution is advised for patients with known hypersensitivity to other glycopeptides. There is currently no data on cross-reactivity between dalbavancin and vancomycin.
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Similarly, it also helps in investigation of binding energy, chemical structure of the adsorbate, interaction between adsorbate molecules and reactivity of adsorbate .Vickerman J.C., Brown A., Reed N.M. “Secondary Ion Mass Spectroscopy: Principle and Applications”, Oxford Science Publication, (1989).
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The Schlosser base (or Lochmann-Schlosser base), the combination of n-butyllithium and potassium tert-butoxide, is commonly cited as a superbase. n-Butyllithium and potassium tert-butoxide form a mixed aggregate of greater reactivity than either component reagent.
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Cis-bending of the R–C≡C bond angle results in the drastic lowering of the energy of the lowest unoccupied molecular orbital, a phenomenon which accounts for the reactivity of strained cycloalkynes from the perspective of molecular orbital theory.
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Inactivation of Runx1 in adult HSCs does not impair function, but rather prevents the differentiation of specific lineages. Differences such as these in the reactivity of HSCs from different niches suggests that the signaling found there is not the same.
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The reaction is carried out at 363K and 30bar oxygen partial pressure, either as pure oxygen or air. Since hot formic acid is corrosive, suitable autoclaves (e.g. Hastelloy) must be used. Reaction times depend on the reactivity of the feed.
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Diethylphosphite is the organophosphorus compound with the formula (C2H5O)2P(O)H. It is a popular reagent for generating other organophosphorus compounds, exploiting the high reactivity of the P-H bond. Diethylphosphite is a colorless liquid. The molecule is tetrahedral.
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Vue features a reactivity system that uses plain JavaScript objects and optimized re-rendering. Each component keeps track of its reactive dependencies during its render, so the system knows precisely when to re-render, and which components to re-render.
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Conjunctivitis is part of the triad of reactive arthritis, which is thought to be caused by autoimmune cross- reactivity following certain bacterial infections. Reactive arthritis is highly associated with HLA-B27. Conjunctivitis is associated with the autoimmune disease relapsing polychondritis.
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Although antibodies exhibit nanomolar affinities toward protein antigens, the specificity against glycans is very limited. In fact, available antibodies may bind only <4% of the 7000 mammalian glycan antigens; moreover, most of those antibodies have low affinity and exhibit cross-reactivity.
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Surrounding a spherical critical mass with a neutron reflector further reduces the mass needed for criticality. A common material for a neutron reflector is beryllium metal. This reduces the number of neutrons which escape the fissile material, resulting in increased reactivity.
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Bent's rule can be used to explain trends in both molecular structure and reactivity. After determining how the hybridisation of the central atom should affect a particular property, the electronegativity of substituents can be examined to see if Bent's rule holds.
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A schematic figure explaining the steps in a typical chemical probing experiment to assay the structure of RNA molecules. RNA chemical probing uses chemicals that react with RNAs. Importantly, their reactivity depends on local RNA structure e.g. base-pairing or accessibility.
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Limitations to take note when using MeDIP are typical experimental factors. This includes the quality and cross-reactivity of 5mC antibodies used in the procedure. Furthermore, DNA detection methods (i.e. array hybridization and high-throughput sequencing) typically involve well established limitations.
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Although less commonly studied, organozincates often have increased reactivity and selectivity compared to the neutral diorganozinc compounds. They have been useful in stereoselective alkylations of ketones and related carbonyls, ring opening reactions. Aryltrimethylzincates participate in vanadium mediated C-C forming reactions.
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Reactivity is a somewhat vague concept in chemistry. It appears to embody both thermodynamic factors and kinetic factors—i.e., whether or not a substance reacts, and how fast it reacts. Both factors are actually distinct, and both commonly depend on temperature.
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However the synthesis of these types of compounds require harsh conditions such as high temperatures and pressures.Louie, Janis, and Robert H. Grubbs. "Metathesis of Electron-Rich Olefins:Â Structure and Reactivity of Electron-Rich Carbene Complexes." Organometallics 21.11 (2002): 2153-164. Web.
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They tend to polymerize in a useful way upon exposure to air. :Representative triglyceride found in a drying oil. The two upper fatty esters display high reactivity toward air owing to their tendency to form pentadienyl and heptadienyl radicals, respectively.
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Pentraxins, collectins, and ficolins are all circulating proteins that are capable of serving as opsonins. They are secreted Pattern recognition receptors (PRRs). These molecules coat the microbes as opsonins and enhance neutrophil reactivity against them through a number of mechanisms.
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Almonds may cause allergy or intolerance. Cross-reactivity is common with peach allergens (lipid transfer proteins) and tree nut allergens. Symptoms range from local signs and symptoms (e.g., oral allergy syndrome, contact urticaria) to systemic signs and symptoms including anaphylaxis (e.g.
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Schweitzer, M.H., J.A. Watt, R. Avci, L. Knapp, L. Chiappe, M. Norell & M. Marshall. (1999). "Beta-keratin specific immunological reactivity in feather-like structures of the Cretaceous alvarezsaurid, Shuvuuia deserti." Journal of Experimental Zoology (Mol Dev Evol), 285: 146-157.
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Burning zirconium was used as a light source in some photographic flashbulbs. Zirconium powder with a mesh size from 10 to 80 is occasionally used in pyrotechnic compositions to generate sparks. The high reactivity of zirconium leads to bright white sparks.
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There is no unique and fully consistent way to define the reactivity series, but it is common to use the three types of reaction listed below, many of which can be performed in a high-school laboratory (at least as demonstrations).
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Eur m 1 is secreted by the Mayne's house dust mite Euroglyphus maynei. Eur m 1 provokes allergic responses from T cells. Der p 1 and Der f 1 show only low levels of cross- reactivity with Eur m 1.
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Phenylacetaldehyde is often contaminated with polystyrene oxide polymer because of the especial lability of the benzylic alpha proton and the reactivity of the aldehyde. Aldol condensation of the initial dimer gives rise to a range of Michael acceptors and donors.
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The immune complex precipitates in the gel to give a thin white line (precipitin line), which is a visual signature of antigen recognition. The method can be conducted in parallel with multiple wells filled with different antigen mixtures and multiple wells with different antibodies or mixtures of antibodies, and antigen-antibody reactivity can be seen by observing between which wells the precipitate is observed. When more than one well is used there are many possible outcomes based on the reactivity of the antigen and antibody selected. The zone of equivalence lines may give a full identity (i.e.
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The accident caused this design to be abandoned and future reactors to be designed so that a single control rod removal would not have the ability to produce the very large excess reactivity that was possible with this design. Today this is known as the "one stuck rod" criterion and requires complete shutdown capability even with the most reactive rod stuck in the fully withdrawn position. The reduced excess reactivity limits the possible size and speed of the power surge. The "one stuck rod" criterion did not originate as a result of the SL-1 accident.
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Sleep plays a role in emotion regulation, although stress and worry can also interfere with sleep. Studies have shown that sleep, specifically REM sleep, down-regulates reactivity of the amygdala, a brain structure known to be involved in the processing of emotions, in response to previous emotional experiences. On the flip side, sleep deprivation is associated with greater emotional reactivity or overreaction to negative and stressful stimuli. This is a result of both increased amygdala activity and a disconnect between the amygdala and the prefrontal cortex, which regulates the amygdala through inhibition, together resulting in an overactive emotional brain.
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In crystalline compounds, the crystalline form can also affect reactivity. However, in all cases, reactivity is primarily due to the sub-atomic properties of the compound. Although it is commonplace to make statements that substance 'X is reactive', all substances react with some reagents and not others. For example, in making the statement that 'sodium metal is reactive', we are alluding to the fact that sodium reacts with many common reagents (including pure oxygen, chlorine, hydrochloric acid, water) and/or that it reacts rapidly with such materials at either room temperature or using a Bunsen flame.
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In vivo mice experiments have shown that a reduction in circulating platelets could reduce cancer metastasis. The oligosaccharide sialylated Lewis x (sLe(x)) is expressed on the surface of tumor cells and can be recognized by E-selectin and P-selectin, playing on a key role in metastasis of the tumor. However, in the 4T1 breast cancer cell line, E-selectin reactivity is sLe(x) dependent while P-selectin reactivity is sLe(x)-independent, suggesting P-selectin binding is Ca2+-independent and sulfation-dependent. One of the sulfated ligands is chondroitin sulfate, a type of glycosaminoglycan (GAG).
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Because furosemide, torsemide and bumetanide are technically sulfa drugs, there is a theoretical risk that patients sensitive to sulfonamides may be sensitive to these loop diuretics. This risk is stated on drug packaging inserts. However, the actual risk of crossreactivity is largely unknown and there are some sources that dispute the existence of such cross reactivity. In one study it was found that only 10% of patients with allergy to antibiotic sulfonamides were also allergic to diuretic sulfonamides, but it is unclear if this represents true cross reactivity or the nature of being prone to allergy.
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On the other side, during in vitro studies of cross-reactivity with the fentanyl antibody between fentanyl and the fentanyl analogs examined, revealed order: fentanyl = butyrylfentanyl > (±)-cis-3-methylfentanyl > benzylfentanyl > alpha-methylfentanyl. High cross- reactivity may be the effect of the shape of the molecule - the shape of butyrfentanyl is closest to the original fentanyl molecule, which makes it easy to bind by fentanyl antibodies. The opioid receptor affinity of fentanyl and its analogs was determined from their inhibitory potency in a binding assay with [3H] fentanyl as the radioligand. The Ki value for butyrfentanyl was Ki=32 ± 4.1 nM.
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The increased reactivity of nanoparticles is one of their most useful properties and is leveraged in fields such as catalysis, consumer products, and energy storage. However, this high reactivity also means that a nanoparticle in a biological environment may have unintended impacts. For example, many nanoparticles such as silver, copper, and ceria interact with cells to produce reactive oxygen species or ROS which can cause premature cell death through apoptosis. Determining the toxicity of a specific nanoparticle requires knowledge of the particle’s chemical composition, shape, size and is a field that is growing alongside advances in nanoparticle research.
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This means that cooling the core with water from nearby sources will not add to the reactivity of the fuel mass. Normally the rate of fission is controlled by light-water compartments called liquid zone controllers, which absorb excess neutrons, and by adjuster rods, which can be raised or lowered in the core to control the neutron flux. These are used for normal operation, allowing the controllers to adjust reactivity across the fuel mass, as different portions would normally burn at different rates depending on their position. The adjuster rods can also be used to slow or stop criticality.
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The harness of the reaction conditions needed for the rearrangement differed based upon the reactivity of the substrates. Piancatelli observed that the more reactive substrates such as 5-methyl-2-furylcarbinols can undergo the rearrangement with much milder conditions in order to avoid any possible side products. Lewis acids were discovered to help drive the reaction to completion as long as there was an equimolar ratio, whereas alkyl groups on the hydroxy-bearing carbon leave the starting material more stable and cause longer reaction times and lower yields with the formation of side products due to the increased reactivity of those carbocations.
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Early life experiences and environmental factors may lead to epigenetic modification at specific gene loci, leading to altered neuronal plasticity, function, and subsequent behavior. Chromatin remodeling in rodent offspring and altered gene expression within the limbic brain regions that may contribute to depression, stress, and anxiety-related disorders in future generations. Variations in maternal care, such as maternal licking and grooming, indicates reduced HPA axis reactivity in subsequent generations. Such HPA axis modifications lead to decreased anxiety-like behavior in adulthood and increased glucocorticoid receptor levels leading to negative feedback on HPA reactivity and further behavioral modifications.
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Noble gas is translated from the German noun , first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity. The name makes an analogy to the term "noble metals", which also have low reactivity. The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas compounds are now known. Rare gases is another term that was used, but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive potassium-40.
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The isocyanate functional groups in TDI react with hydroxyl groups to form carbamate (urethane) links. The two isocyanate groups in TDI react at different rates: The 4-position is approximately four times more reactive than the 2-position. 2,6-TDI is a symmetrical molecule and thus has two isocyanate groups of similar reactivity, similar to the 2-position on 2,4-TDI. However, since both isocyanate groups are attached to the same aromatic ring, reaction of one isocyanate group will cause a change in the reactivity of the second isocyanate group.. It is also sometimes used in Rocket propellants.
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Beads of an ion-exchange polymer. In polymer chemistry, the equivalent weight of a reactive polymer is the mass of polymer which has one equivalent of reactivity (often, the mass of polymer which corresponds to one mole of reactive side-chain groups). It is widely used to indicate the reactivity of polyol, isocyanate, or epoxy thermoset resins which would undergo crosslinking reactions through those functional groups. It is particularly important for ion-exchange polymers (also called ion-exchange resins): one equivalent of an ion-exchange polymer will exchange one mole of singly charged ions, but only half a mole of doubly charged ions.
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It is used to prevent deep venous clots, particularly in situations with a high risk of clot formation, such as after hip surgery. It is also used as a heparin substitute in heparin-induced thrombocytopenia (HIT) which may otherwise cause paradoxical thrombosis. Danaparoid is used for thrombosis prophylaxis and treatment in heparin-induced thrombocytopenia patients. Although pre-treatment serological cross-reactivity with heparin- induced antibodies can occur in 5.2% of the patients it bears no systematic relationship with clinical cross-reactivity, 3.2% in the same study of 1478 patients with acute HIT [Magnani & Gallus Thromb Haemost 2006;95:967-81](ESRA).
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Copolymerization is particularly useful in tuning the glass transition temperature, which is important in the operating conditions of polymers; it is assumed that each monomer occupies the same amount of free volume whether it is in a copolymer or homopolymer, so the glass transition temperature (Tg) falls between the values for each homopolymer and is dictated by the mole or mass fraction of each component. A number of parameters are relevant in the composition of the polymer product; namely, one must consider the reactivity ratio of each component. Reactivity ratios describe whether the monomer reacts preferentially with a segment of the same type or of the other type. For example, a reactivity ratio that is less than one for component 1 indicates that this component reacts with the other type of monomer more readily. Given this information, which is available for a multitude of monomer combinations in the “Wiley Database of Polymer Properties”,Greenley, Robert.
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Iron-based catalysts can tolerate lower ratios, due to intrinsic water-gas shift reaction activity of the iron catalyst. This reactivity can be important for synthesis gas derived from coal or biomass, which tend to have relatively low H2:CO ratios (< 1).
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Hu, J. Y., Morita, T., Magara, Y., & Aizawa, T. (2000). Evaluation of reactivity of pesticides with ozone in water using the energies of frontier molecular orbitals. Water Research, 34(8), 2215-2222. Among four different herbicide groups, cyanazine degrades the fastest in soil.
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Uranocene Organouranium chemistry is the science exploring the properties, structure and reactivity of organouranium compounds, which are organometallic compounds containing a carbon to uranium chemical bond. The field is of some importance to the nuclear industry and of theoretical interest in organometallic chemistry.
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A mass may be exactly critical without being a perfect homogeneous sphere. More closely refining the shape toward a perfect sphere will make the mass supercritical. Conversely changing the shape to a less perfect sphere will decrease its reactivity and make it subcritical.
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Due to the subsequent lack of emotional control, sleep deprivation may be associated with depression, impulsivity, and mood swings. Additionally, there is some evidence that sleep deprivation may reduce emotional reactivity to positive stimuli and events and impair emotion recognition in others.
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Possible reactivity at aldehydes include nucleophilic attack and addition of allylmetals. The stereoselectivity of nucleophilic attack at alpha-chiral aldehydes may be described by the Felkin–Anh or polar Felkin Anh models and addition of achiral allylmetals may be described by Cram’s rule.
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Ed: J. Čejka, H. van Bekkum. Adjacent layers of the sheets are related by an inversion point. The estimated pore size of the channel running parallel with the corrugations is 5.4–5.6 Å.Modeling of Structure and Reactivity in Zeolites (1992). Ed: C.R.A. Catlow.
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The immune system recognizes foreign pathogens and eliminates them. This occurs in several phases. In the early inflammation phase, the pathogens are recognized by antibodies that are already present (innate or acquired through prior infection; see also cross-reactivity). Immune-system components (e.g.
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The amygdala in the brain is part of the limbic system, and is responsible for processing and regulating emotions. This could possibly explain as to why those suffering from low arousal often lack empathy as well as emotional reactivity to other people.
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Cyclopropene is an organic compound with the formula 34. It is the simplest cycloalkene. Because the ring is highly strained, cyclopropene is difficult to prepare and highly reactive. This colorless gas has been the subject for many fundamental studies of bonding and reactivity.
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In chemistry, solvent effects are the influence of a solvent on chemical reactivity or molecular associations. Solvents can have an effect on solubility, stability and reaction rates and choosing the appropriate solvent allows for thermodynamic and kinetic control over a chemical reaction.
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Many studies have associated perspective-taking with empathy. Psychologist Mark Davis suggested that empathy consists of multiple dimensions. To assess this, Davis developed the Interpersonal Reactivity Index (IRI). The IRI consists of four subscales: fantasy, empathic concern, personal distress, and perspective-taking.
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Lipid kinases phosphorylate lipids in the cell, both on the plasma membrane as well as on the membranes of the organelles. The addition of phosphate groups can change the reactivity and localization of the lipid and can be used in signal transmission.
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Ethyl cyanoacetate is an organic compound that contains a carboxylate ester and a nitrile. It is a colourless liquid with a pleasant odor. This material is useful as a starting material for synthesis due to its variety of functional groups and chemical reactivity.
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Being a widely available reagent, TsCl has been heavily examined from the perspective of reactivity. It is used in dehydrations to make nitriles, isocyanides and diimides. In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.
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"Plasma steroid-binding globulins mediate stress reactivity in the tree lizard, Urosaurus ornatus ". General and Comparative Endocrinology 120: 289-299. Its life history and costs of reproduction have been documented in field populations in New Mexico and Arizona.French SS, Moore MC (2008).
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Gaseous methylglyoxal has two carbonyl groups, an aldehyde and a ketone. In the presence of water, it exists as hydrates and oligomers. The formation of these hydrates is indicative of the high reactivity of MGO, which is relevant to its biological behavior.
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UDP-glucuronosyltransferase 2B15 is an enzyme that in humans is encoded by the UGT2B15 gene. The UGTs are of major importance in the conjugation and subsequent elimination of potentially toxic xenobiotics and endogenous compounds. UGT2B8 demonstrates reactivity with estriol. See UGT2B4 (MIM 600067).
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Parvalbumin has been identified as an allergen causing fish allergy (but not shellfish allergy). Bony fishes manifest β-parvalbumin and cartilaginous fishes such as sharks and rays manifest α-parvalbumin; allergenicity to bony fishes has a low cross- reactivity to cartilaginous fishes.
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Perceived racism and cardiovascular reactivity and recovery to personally relevant stress. Health Psychology, 25, 364-369.Pavalko, E. K., Mossakowski, K. N., & Hamilton, V. J. (2003). Does perceived discrimination affect health? Longitudinal relationships between work discrimination and women’s physical and emotional health.
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As-grown fullerene nanotubes have hexagonal shapes and face-centered cubic crystal structures. Owing to their relatively large inner diameters (ca. 100 nm) and low reactivity they can accommodate a wide range of nanoparticles. C60 nanotubes decompose upon heating to in air.
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The SARL programming language is a modular agent-oriented programming language. It aims at providing the fundamental abstractions for dealing with concurrency, distribution, interaction, decentralization, reactivity, autonomy and dynamic reconfiguration.Rodriguez, S., Gaud, N., & Galland, S. (2014). SARL: a general-purpose agent-oriented programming language.
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This binding mode may play a role in the catalytic hydrogenation cycle. : Structure of Co(DIP)Cl where DIP = C5H3N-2,6-(C(NAr)Me)2 (Ar = 2,6-diisopropylphenyl) derived from diacetylpyridine and 2,6-diisopropylaniline). The reactivity of cobalt- and iron-DIP complexes are similar.
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Thorson, Timothy A. Ion Flow and Fusion Reactivity Characterization of a Spherically Convergent Ion Focus. Thesis. Wisconsin Madison, 1996. Madison: University of Wisconsin, 1996. Print. The halo mode occurs in higher pressure tanks, and as the vacuum improves, the device transitions to star mode.
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1,3-Propanedithiol is mainly used for the protection of aldehydes and ketones via their reversible formation of dithianes. A prototypical reaction is its formation of 1,3-dithiane from formaldehyde. The reactivity of this dithiane illustrates the concept of umpolung. Alkylation gives thioethers, e.g. 1,5-dithiacyclooctane.
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Extensions of this reactivity to intermolecular systems have resulted in i) a new synthetic route to complex tetrahydrofurans by a "polar-radical-crossover cycloaddition" (PRCC reaction) of an allylic alcohol with an olefin, and ii) the anti-Markovnikov addition of carboxylic acids to olefins.
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ACAD8 is an isobutyryl-CoA dehydrogenase that functions in the catabolism of branched-chain amino acids including valine, and shows high reactivity toward isobutyryl-CoA. ACAD8 is responsible for the third step in the breakdown of valine and converts isobutyryl-CoA into methylacrylyl-CoA.
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Design parameters include type of mill, milling container, milling speed, milling time, type, size, and size distribution of the grinding medium, ball-to-powder weight ratio, extent of filling the vial, milling atmosphere, process control agent, temperature of milling, and the reactivity of the species.
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Nanotechnology is expected to deal more efficiently with contaminants which convectional water treatment systems struggle to treat, including bacteria, viruses and heavy metals. This efficiency generally stems from the very high specific surface area of nanomaterials which increases dissolution, reactivity and sorption of contaminants.
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Despite its high reactivity, DMDO displays good selectivity for olefins. Typically, electron deficient olefins are oxidized more slowly than electron rich ones. DMDO will also oxidize several other functional groups. For example, DMDO will oxidize primary amines to nitro compounds and sulfides to sulfoxides.
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Certification/analytical accuracy is defined as the agreement of measured values with its true value. Certification values are determined statistically, considering the uncertainties accompanied by the international standard (reference standard) to which it is traceable, instrument uncertainty, and instability (reactivity) of gas in the container.
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Among the transition metals, the noble metals (generally Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au) correspond to the noble gases, although concern has been raised about the inclusion of silver due to its greater chemical reactivity compared to the other seven noble metals.
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90°) and longer Si-N (c. 1.73Å) and Si-metal bond length compared to a carbene's N-C-N angle (c. 100°), C-N bond length (c. 1.37Å), and C-metal length means NHSi are less sterically demanding, leading to reactivity not seen in carbenes.
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15N isotope enriched NaNO2 In organic synthesis isotope enriched sodium nitrite-15N can be used instead of normal sodium nitrite as their reactivity is nearly identical in most reactions. The obtained products carry isotope 15N and hence Nitrogen NMR can be efficiently carried out.
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Intramolecular FLPs are where the Lewis Acid and Lewis Base are combined in one molecule by a covalent linker. Despite the improved ‘pre-organisational effects’, rigid intramolecular FLP frameworks are thought to have a reduced reactivity to small molecules due to a reduction in flexibility.
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The survey contained measures of three aspects: adolescent egocentrism, self-consciousness, and interpersonal reactivity. The result revealed that scores of egocentrism were not, on average, significantly different between adolescents and young adults (19-30), which indicates that egocentrism in adolescence may continue into adulthood.
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The bite angle of the diphosphine influences the reactivity of the metal center.Birkholz, M.-N., Freixa, Z., van Leeuwen, P. W. N. M., "Bite angle effects of diphosphines in C-C and C-X bond forming cross coupling reactions", Chem. Soc. Rev. 2009, vol.
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The end result is that reactors designed to take advantage of Doppler broadening will decrease their reactivity as temperature increases, creating a passive safety measure. This tends to be more relevant to gas-cooled reactors, as other mechanisms are dominant in water cooled reactors.
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2Na + 2H2O ->2NaOH + H2 This reaction is commonly used for demonstrating the reactivity of alkali metals in academic environments; however, it is not commercially viable, as the isolation of sodium metal is typically performed by reduction or electrolysis of sodium compounds including sodium hydroxide.
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There are four characteristics chemical wastes may have to be considered as hazardous. These are Ignitability, Corrosivity, Reactivity, and Toxicity. This type of hazardous waste must be categorized as to its identity, constituents, and hazards so that it may be safely handled and managed.
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This center is located in Ōarai, Ibaraki Prefecture, close to, but not at the same site as Tokai-mura. It houses the Jōyō reactor, the Japan Materials Testing Reactor, the new High-temperature engineering test reactor, an environmental reactivity monitoring center, and a children's museum.
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Parakhinite crystallizes in the tetragonal system. Khinite and parakhinite are also called khinite-4O and khinite-3T, respectively. Khinite and parakhinite are identical in colour and many other properties, like reactivity. They do differ in optical properties: Khinite is biaxial (+), while parakhinite is uniaxial (-).
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The C=C double bond is a site of high reactivity. polymerize gives polyvinylsulfonic acid, especially when used as a comonomer with functionalized vinyl and (meth)acrylic acid compounds. It is a colorless, water-soluble liquid, although commercial samples can appear yellow or even red.
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Active esters are mainly used as acylating agents. They undergo the same reactions as their unactivated analogues but do so more rapidly. They are prone to hydrolysis, for example. Of great interest is the enhanced reactivity of active esters toward amines to give amides.
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It is usually detected only at very low pressures, very low temperatures, or as a short-lived intermediate in chemical reactions. W. B. DeMore and S. W. Benson (1964), Preparation, properties, and reactivity of methylene. In Advances in Photochemistry, John Wiley & Sons, 453 pages.
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Flory's earliest work in polymer science was in the area of polymerization kinetics at the DuPont Experimental Station. In condensation polymerization, he challenged the assumption that the reactivity of the end group decreased as the macromolecule grew, and by arguing that the reactivity was independent of the size, he was able to derive the result that the number of chains present decreased with size exponentially. In addition polymerization, he introduced the important concept of chain transfer to improve the kinetic equations and remove difficulties in understanding the polymer size distribution. In 1938, after Carothers' death, Flory moved to the Basic Science Research Laboratory at the University of Cincinnati.
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For example, it is commonly asserted that the reactivity of group one metals (Na, K, etc.) increases down the group in the periodic table, or that hydrogen's reactivity is evidenced by its reaction with oxygen. In fact, the rate of reaction of alkali metals (as evidenced by their reaction with water for example) is a function not only of position within the group but particle size. Hydrogen does not react with oxygen—even though the equilibrium constant is very large—unless a flame initiates the radical reaction, which leads to an explosion. Restriction of the term to refer to reaction rates leads to a more consistent view.
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These anionic fullerene cages are very stable molecules and do not have the reactivity associated with ordinary empty fullerenes. They are stable in air up to very high temperatures (600 to 850 °C). The lack of reactivity in Diels- Alder reactions is utilised in a method to purify [C80]−6 compounds from a complex mixture of empty and partly filled fullerenes of different cage size. In this method Merrifield resin is modified as a cyclopentadienyl resin and used as a solid phase against a mobile phase containing the complex mixture in a column chromatography operation. Only very stable fullerenes such as [Sc3N]+6@[C80]−6 pass through the column unreacted.
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The design accounted for steam collapse in the core when the fuel element temperature falls below 265 °C, coolant vaporization in fuel channels in cold reactor state, and sticking of some emergency protection rods. However, the slow insertion speed of the control rods, together with their design causing localized positive reactivity as the displacer moves through the lower part of the core, created a number of possible situations where initiation of the EPS could itself cause or aggravate a reactor runaway. The computer system for calculation of the reactivity margin was collecting data from about 4,000 sources. Its purpose was to assist the operator with steady-state control of the reactor.
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Because both components are so reactive a molecule does not carry an aldehyde and an amine group at the same time unless the amine group is fitted with a protective group. As a further demonstration of reactivity one study explored the properties of an α-formyl aziridine which was found to dimerize as an oxazolidine on formation from the corresponding ester by organic reduction with DIBAL:The dimer reacts with sodium borohydride through the monomer it is in equilibrium with to the aziridine alcohol Formyl Aziridine Reactivity Iminium ion formation is prohibited in this molecule because the azirine group and the formyl group are said to be orthogonal.
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Part of the exceptional reactivity of compounds of hyper leaving groups has been ascribed to the entropic favorability of having one molecule split into three. The ability of hyper leaving groups is enhanced by entropic factors Dialkyl halonium ions have also been isolated and characterized for simple alkyl groups. These compounds, despite their extreme reactivity towards nucleophiles, can be obtained pure in the solid state with very weakly nucleophilic counterions such as SbF and CHB11Cl11−. The strongly electrophilic nature of these compounds engendered by their attachment to extremely labile R-X (R = alkyl, X = Cl, Br, I) leaving groups is illustrated by their propensity to alkylate very weak nucleophiles.
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Intense but largely fruitless efforts have been undertaken to emulate this reactivity. Methanol is more easily oxidized than is the feedstock methane, so the reactions tend not to be selective. Some strategies exist to circumvent this problem. Examples include Shilov systems and Fe- and Cu containing zeolites.
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It has been reported that the reactivity of an oxygen atom generated in such a way on a platinum surface is different from that of chemisorbed oxygen atoms. Elucidating the role of hot atoms on surfaces will lead to a deeper understanding of the mechanism of reactions.
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Furthermore, the trait negative urgency, the propensity to engage in risky behaviour in response to distress, is highly predictive of certain aspects of substance abuse in adolescents. Early individual differences in emotional differences in reactivity and regulation underlie the later emergence of the trait 'negative urgency'.
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Her main research interests are the synthesis of nanostructured materials with tunable surface properties and the experimental investigation of structure-reactivity relationships in thermal and electro-catalysis using in situ and operando methods. Applications of her work are in the areas of environmental remediation and energy conversion.
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Phosphoramidite: general structure A phosphoramidite (RO)2PNR2 is a monoamide of a phosphite diester. The key feature of phosphoramidites is their markedly high reactivity towards nucleophiles catalyzed by weak acids e.c., triethylammonium chloride or 1H-tetrazole. In these reactions, the incoming nucleophile replaces the NR2 moiety.
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Wynne V. Kandur, Kathleen J. Richert, Curtis J. Rieder, Andrew M. Thomas, Chunhua Hu, Joseph W. Ziller, and K. A. Woerpel (2014): "Synthesis and reactivity of 1,2-dioxolanes from β,γ-epoxy ketones". rganic letters, volume 16, issue 10, pages 2650–2653. "C3F6O2 Hexafluoro-1,2-dioxolane".
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Akin to the chemistry of alcohols, thiols form sulfides, thioacetals, and thioesters, which are analogous to ethers, acetals, and esters respectively. Thiols and alcohols are also very different in their reactivity, thiols being more easily oxidized than alcohols. Thiolates are more potent nucleophiles than the corresponding alkoxides.
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Post-revision peripheral T cell repertoire is strengthening all essential features of self-tolerant and self-MHC-restricted T cell repertoire generated in the thymus while keeping all its hallmarks - reactivity towards foreign antigens and homeostatic proliferation in response to self-MHC, so-called tonic signaling.
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Examples of high reactivity exhibited by metal-silox compounds include the C-O bond in carbon monoxide and the C-N bond in pyridine.Peter T. Wolczanski "Chemistry of electrophilic metal centres coordinated by silox (tBu3SiO), tritox (tBu3CO) and related bifunctional ligands" Polyhedron, 1995, 14, 3335-3362. .
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Is not recognized as a stand alone diagnosis in the manuals ICD-10 or in the recently updated DSM-5 but, unusual reactivity to sensory input or unusual interest in sensory aspects is included as a possible but not necessary criterion for the diagnosis of autism.
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Additionally, packed particle columns must be maintained in a solvent environment and cannot be exposed to air during or after the packing procedure. If exposed to air, the pores dry out and no longer provide adequate surface area for reactivity; the column must be repacked or discarded.
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Carbene addition to alkenes Singlet and triplet carbenes exhibit divergent reactivity. Singlet carbenes generally participate in cheletropic reactions as either electrophiles or nucleophiles. Singlet carbenes with unfilled p-orbital should be electrophilic. Triplet carbenes can be considered to be diradicals, and participate in stepwise radical additions.
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Chemical metallurgy is the science of obtaining metals from their ores, and of considering reactions of metals which are usually considered with an approach of disciplines belonging to chemistry. As such, it involves reactivity of metals which are also dealt in detail by electrochemistry and corrosion.
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This was discovered in the earliest nuclear reactors built by the Manhattan Project for plutonium production. As a result, the designers made provisions in the design to increase the reactor's reactivity (the number of neutrons per fission that go on to fission other atoms of nuclear fuel).
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For strongly temperature-dependent α, this approximation is only useful for small temperature differences ΔT. Temperature coefficients are specified for various applications, including electric and magnetic properties of materials as well as reactivity. The temperature coefficient of most of the reactions lies between −2 and 3.
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Toxic epidermal necrolysis has occurred from the use of tetrazepam including at least one reported death. Stevens–Johnson syndrome and erythema multiforme has been reported from use of tetrazepam. Cross-reactivity with other benzodiazepines does not typically occur in such patients. Exanthema and eczema may occur.
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With Lewis acid catalysts like ferric chloride or aluminium chloride, acyl chlorides participate in Friedel-Crafts acylations, to give aryl ketones: :400x400px Because of the harsh conditions and the reactivity of the intermediates, this otherwise quite useful reaction tends to be messy, as well as environmentally unfriendly.
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Sodium cyanide is a poisonous compound with the formula NaCN. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its high reactivity toward metals.
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Dr. Chatgilialoglu is actually the leader of his research group in Bologna at ISOF-CNR. His actual research activities are focused on Free Radical Chemistry with a multidisciplinary approach including structure-reactivity-mechanism studies leading to applications in synthetic methodologies, materials science, and in life sciences.
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Crustaceans (shrimp, crab, lobster, etc.) and molluscs (mussel, oyster, scallop, squid, octopus, snail, etc.) are different invertebrate classes, but the allergenic protein tropomyosin is present and responsible for cross-reactivity. People with latex allergy often also develop allergies to bananas, kiwifruit, avocados, and some other foods.
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She was director, between 1996 and 2000, of the Structure and Reactivity of Interfaces Laboratory (SRI), a Université Pierre et Marie Curie - Centre national de la recherche scientifique (CNRS) joint unit. Since 2004, she has been a professor at the Georgia Institute of Technology at Atlanta.
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Because oxygen is more electronegative than carbon, carbonyl compounds often have resonance structures which affect their reactivity. This relative electronegativity draws electron density away from carbon, increasing the bond's polarity, therefore making carbon an electrophile (i.e. slightly positive). Carbon can then be attacked by nucleophiles (e.g.
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Similarly, they undergo inverse demand Diels-Alder reactions. 352px The reactivity of enol ethers is highly dependent on the presence of substituents alpha to oxygen. The vinyl ethers are susceptible to polymerization to give polyvinyl ethers. Some vinyl ethers also find some use as inhalation anesthetics.
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The TRISO particles are either dispersed in a pebble for the pebble bed design or molded into compacts/rods that are then inserted into the hexagonal graphite blocks. The QUADRISO fuel concept conceived at Argonne National Laboratory has been used to better manage the excess of reactivity.
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Nitrous oxide is a colourless, non-toxic gas with a faint, sweet odour. Nitrous oxide supports combustion by releasing the dipolar bonded oxygen radical, and can thus relight a glowing splint. is inert at room temperature and has few reactions. At elevated temperatures, its reactivity increases.
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A high PRx indicating disturbed pressure autoregulation predicts poor outcome in traumatic brain injury.Sorrentino, E., Diedler, J., Kasprowicz, M., Budohoski, K., Haubrich, C., Smielewski, P., Outtrim, J., Manktelow, A., Hutchinson, P. and Pickard, J. (2012). Critical thresholds for cerebrovascular reactivity after traumatic brain injury. Neurocritical care 16, 258-266.
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Surgical gowns must also conform to the ASTM F2407 standard for tear resistance, seam strength, lint generation, evaporative resistance, and water vapor transmission. Because surgical gowns are considered to be a surface-contacting device with intact skin, FDA recommends that cytotoxicity, sensitization, and irritation or intracutaneous reactivity is evaluated.
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More recently, fly ash has been used as a component in geopolymers, where the reactivity of the fly ash glasses can be used to create a binder similar to a hydrated Portland cement in appearance, but with potentially superior properties, including reduced CO2 emissions, depending on the formulation.
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The rule is not helpful for complexes of metals that are not transition metals, and interesting or useful transition metal complexes will violate the rule because of the consequences deviating from the rule bears on reactivity. The rule was first proposed by American chemist Irving Langmuir in 1921.
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To be sure, photochemical reactivity emerges when the internal conversion makes the system explore the nuclear configuration space such that new chemical species are formed. There is a plethora of femtosecond pump-probe spectroscopic techniques to reveal details of these processes occurring, for example, in the process of vision.
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Acryloyl chloride, also known as 2-propenoyl chloride or acrylic acid chloride, is the organic compound with the formula CH2=CHCO(Cl). It is a colorless liquid, although aged samples appear yellow. Although it belongs to the acid chlorides group of compounds, its synthesis and reactivity are somewhat different.
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These excellent leaving groups, such as triflate (trifluoromethanesulfonate) and nonaflate (nonafluorobutanesulfonate), are highly prone to SN1 reactivity. Utilization of these super leaving groups allowed researchers for the first time to move beyond speculation about the existence of such vinyl cations. Vinyl cation formation through carbon-halogen bond cleavage.
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Mixtures containing hexaethyl tetraphosphate are produced by heating diethyl ether and phosphorus pentoxide. The reaction entails cleavage of the C-O bond of the ether. The molecule contains three pyrophosphate bonds, which are the sites of high reactivity. The compound exists as two diastereomers, the meso- and dl-isomers.
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A variety of tree nuts, seeds, legumes, fruits and food ingredients are assessed for cross- reactivity in the walnut ELISA assay. The modified sandwich ELISA can be used to detect walnuts residues with sheep antiroasted walnut and rabbit antiroasted walnut antisera used as the capture and detector antibodies respectively.
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For example, many FLPs split hydrogen molecules. Thus, a mixture of tricyclohexylphosphine (PCy3) and tris(pentafluorophenyl)borane reacts with hydrogen to give the respective phosphonium and borate ions: :PCy3 + B(C6F5)3 + H2 -> [HPCy3]+ [HB(C6F5)3]- This reactivity has been exploited to produce FLPs which catalyse hydrogenation reactions.
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New version released in the summer of 2013. From an ergonomic point of view, this new model brings an ISO accessory shoe and a tilting screen. The technical developments concerning the sensor becomes backlit. The quality of low light images is thus improved as well as the reactivity (AF).
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Because BSM is frequently applied as a coating on a material that will interact with the human body, it is important to minimize disadvantageous interactions with tissues and cells. Two considerations include reducing tissue reactivity, as in inflammatory and immune responses, and preventing the adsorption of particles, like bacteria.
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Byers serves on the Board of Directors for Reactivity, MyThings, and Flywheel Ventures. He also serves on the following advisory boards and committees: American Society for Engineering Education's Entrepreneurship Division, Harvard Business School's California Research Center, and the National Foundation for Teaching Entrepreneurship (NFTE) for inner-city youth.
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During the acute phase of the disease, MAT is not specific in detecting a serotype of Leptospira because of cross-reactivity between the serovars. In the convalescent phase, MAT is more specific in detecting the serovar types. MAT requires a panel of live antigens and requires laborious work.
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Reber maintains that human consciousness should be viewed as a pole on a continuum of subjective, phenomenal states that can be traced back to simple reactivity of organic forms and not as something special in our universe.Reber, A. S. (1997). Caterpillars and consciousness. Philosophical Psychology, 10, 437-450.
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Like many alkyl halides, it is relativity reactive, although not as reactive as iodides and bromides (I>Br>Cl>F), because of this reactivity, alkyl fluorides are more stable than others, and are not readily reactive.Clark, J. (2015, December 18). Physical Properties of Alkyl Halides. In Chemistry LibreTexts.
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Virtual reality cue reactivity, though still in an early stage of development, is aimed at becoming a much more efficient version of an actor-based simulation. Carter, Brian L., et al. "Location and Longing: The Nicotine Craving Experience in Virtual Reality." Drug & Alcohol Dependence 95.1 (2008): 73-80.
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When temperature returns to an acceptable level, the hydrogen will again combine with the uranium metal, forming uranium hydride, restoring moderation and the nuclear reaction will start again. This makes the reactor a self-regulating, dynamic system, as with a rise in temperature, nuclear reactivity will substantially decrease, and with a fall in temperature, nuclear reactivity will substantially increase. Thus, this reactor design is self-regulating, meltdown is impossible, and the design is inherently safe. From a safety point of view, the design leverages the technology used in the TRIGA reactor, which uses uranium zirconium hydride (UZrH) fuel and is the only reactor licensed by the U.S. Nuclear Regulatory Commission for unattended operation.
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A semi-empirical method for the prediction of reactivity ratios is called the Q-e scheme which was proposed by Alfrey and Price in 1947. This involves using two parameters for each monomer, Q and e . The reaction of M_1 radical with M_2 monomer is written as k_{12} = P_1Q_2exp(-e_1e_2) while the reaction of M_1 radical with M_1 monomer is written as k_{11} = P_1Q_1exp(-e_1e_1) Where Q is the measure of reactivity of monomer via resonance stabilization, and e is the measure of polarity of monomer (molecule or radical) via the effect of functional groups on vinyl groups. Using these definitions, r_1 and r_2 can be found by the ratio of the terms.
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In pressurized water reactors the coolant water is used as a moderator by letting the neutrons undergo multiple collisions with light hydrogen atoms in the water, losing speed in the process. This moderating of neutrons will happen more often when the water is denser, because more collisions will occur. The use of water as a moderator is an important safety feature of PWRs, as any increase in temperature causes the water to expand and become less dense; thereby reducing the extent to which neutrons are slowed down and hence reducing the reactivity in the reactor. Therefore, if reactivity increases beyond normal, the reduced moderation of neutrons will cause the chain reaction to slow down, producing less heat.
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The extra rod worth was in part due to the decision to load only 40 of the 59 fuel assemblies with nuclear fuel, thus making the prototype reactor core more active in the center. In normal operation control rods are withdrawn only enough to cause sufficient reactivity for a sustained nuclear reaction and power generation. In this accident, however, the reactivity addition was sufficient to take the reactor prompt critical within a time estimated at 4 milliseconds. That was too fast for the heat from the fuel to get through the aluminum cladding and boil enough water to fully stop the power growth in all parts of the core via negative moderator temperature and void feedback.
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Physical organic chemistry, a term coined by Louis Hammett in 1940, refers to a discipline of organic chemistry that focuses on the relationship between chemical structures and reactivity, in particular, applying experimental tools of physical chemistry to the study of organic molecules. Specific focal points of study include the rates of organic reactions, the relative chemical stabilities of the starting materials, reactive intermediates, transition states, and products of chemical reactions, and non-covalent aspects of solvation and molecular interactions that influence chemical reactivity. Such studies provide theoretical and practical frameworks to understand how changes in structure in solution or solid-state contexts impact reaction mechanism and rate for each organic reaction of interest.
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Before the development of SpyTag/SpyCatcher, the pair Isopeptag/Pilin-C was created from protein Spy0128 of Streptococcus pyogenes. Following SpyTag/SpyCatcher, the fully orthogonal pair SnoopTag/SnoopCatcher was developed from the RrgA protein of Streptococcus pneumoniae that has no cross-reactivity with SpyTag/SpyCatcher. Note that SnoopTag/SnoopCatcher forms an isopeptide bond between a Lys-Asn instead of Lys-Asp found in SpyTag/SpyCatcher. The pair SdyTag/SdyCatcher was also developed in the same year from Streptococcus dysgalactiae fibronectin-binding protein CnaB domain, but since the protein has sequence similarity to the parent protein where SpyTag/SpyCatcher is derived from, this Tag/Catcher pair has cross-reactivity with the latter pair.
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Steiner, L.A., Czosnyka, M., Piechnik, S.K., Smielewski, P., Chatfield, D., Menon, D.K. and Pickard, J.D. (2002). Continuous monitoring of cerebrovascular pressure reactivity allows determination of optimal cerebral perfusion pressure in patients with traumatic brain injury. Critical care medicine 30, 733-738. CPP values above CPPopt are believed to cause hyperemia, i.e.
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Hemilabile ligands contain at least two electronically different coordinating groups and form complexes where one of these is easily displaced from the metal center while the other remains firmly bound, a behaviour which has been found to increase the reactivity of catalysts when compared to the use of more traditional ligands.
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CD300A (Cluster of Differentiation 300A) is a human gene. The CMRF35 antigen (CMRF35A; MIM 606786), which was identified by reactivity with a monoclonal antibody, is present on monocytes, neutrophils, and some T and B lymphocytes. CMRF35H is recognized by the same antibody and is distinct from CMRF35 (Green et al., 1998).
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Fluorographene is thermally stable, resembling polytetrafluoroethylene; however, chemically it is reactive. It can be transformed back into graphene by reaction with KI under higher temperature. During reactions of fluorographene with NaOH and NaSH simultaneous reductive defluorination and substitution are observed. The reactivity of fluorographene represents a facile way towards graphene derivatives.
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CMRF35-like molecule 6 (CLM-6) also known as CD300 antigen-like family member C (CD300c) is a protein that in humans is encoded by the CD300C gene. The CMRF35 antigen, which was identified by reactivity with a monoclonal antibody, is present on monocytes, neutrophils, and some T and B lymphocytes.
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Even though it gives 100% sensitivity, it has not been tested with human sera for cross-reactivity, and it may show a high false positive result. Loop-mediated isothermal amplification (LAMP) is highly sensitive (~2.5 times that of multiplex PCR), without false positive, for differentiating the taenid species from faecal samples.
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The reactivity of pyrylium salts toward nucleophiles makes them useful materials for producing other compounds with stronger aromatic character. Pyrylium salts afford pyridines with ammonia, pyridinium salts with primary amines, pyridine- N-oxides with hydroxylamine, phosphabenzenes with phosphine derivatives, thiopyrylium salts with hydrogen sulfide, and benzene derivatives with acetonitrile or nitromethane.
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Tetrakis(cyclopentadienyl)thorium(IV) an organoactinide compound Organoactinide chemistry is the science exploring the properties, structure and reactivity of organoactinide compounds, which are organometallic compounds containing a carbon to actinide chemical bond. Like most organometallic compounds, the organoactinides are air sensitive and need to be handled using the appropriate methods.
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An allergy to a PPI like rabeprazole may take the form of type I hypersensitivity or delayed hypersensitivity reactions. A selective (pattern C—see below for a discussion of cross-reactivity patterns) type I hypersensitivity reaction to rabeprazole resulting in anaphylaxis has been reported, as well as several whole group hypersentivities.
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The seeds can be dried and stored. The seeds have a strong sulphur smell, which is due to the presence of thioproline. The treebean therefore requires an acquired taste Thangjam, R. and D. D. Maibam. (2012). Sulphur free radical reactivity of thioproline and crude extracts of Parkia timoriana (DC.) Merr.
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Light emitted from solid particles is defined by black-body radiation. The temperature of the spark is controlled by the reactivity of the metal. Higher reactive metals lead to hotter sparks. The electronegativity has found to be an helpful indicator to estimate the temperature and consequently the color of a spark.
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Substitution is perhaps most useful method in introducing vinyl iodide into the molecule. Halogen-exchange can be useful since vinyl iodides are more reactivity than other vinyl halides. Buchwald group demonstrates a halogen- exchange from vinyl bromide to vinyl iodide with copper catalyst under mild conditions.Klapars, Artis, and Stephen L. Buchwald.
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Acyl halides and anhydrides of carboxylic acids are also commonly used acylating agents. In some cases, active esters exhibit comparable reactivity. All react with amines to form amides and alcohols to form esters by nucleophilic acyl substitution. Acylation can be used to prevent rearrangement reactions that would normally occur in alkylation.
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The mechanism of interaction between the infecting organism and the host is unknown. Synovial fluid cultures are negative, suggesting that reactive arthritis is caused either by an autoimmune response involving cross-reactivity of bacterial antigens with joint tissues or by bacterial antigens that have somehow become deposited in the joints.
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Illustrative of its reactivity is its cyanation to allyl cyanide (CH2=CHCH2CN). Being a reactive alkyl halide, it undergoes reductive coupling to give diallyl: :2 ClCH2CH=CH2 \+ Mg → (CH2)2(CH=CH2)2 \+ MgCl2 It undergoes oxidative addition to palladium(0) to give allylpalladium chloride dimer, (C3H5)2Pd2Cl2. Dehydrohalogenation gives cyclopropene.
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Elemental potassium does not occur in nature because of its high reactivity. It reacts violently with water (see section Precautions below) and also reacts with oxygen. Orthoclase (potassium feldspar) is a common rock-forming mineral. Granite for example contains 5% potassium, which is well above the average in the Earth's crust.
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The relative reactivity of the hexafluorides of S, Se, and Te follows the order TeF6 > SeF6 > SF6, the latter being completely inert toward hydrolysis until high temperatures. SeF6 also resists hydrolysis. The gas can be passed through 10% NaOH or KOH without change, but reacts with gaseous ammonia at 200 °C.
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Anti- nRNP autoantibodies to nRNP A and nRNP C initially targeted restricted, proline-rich motifs. Antibody binding subsequently spread to other epitopes. The similarity and cross-reactivity between the initial targets of nRNP and Sm autoantibodies identifies a likely commonality in cause and a focal point for intermolecular epitope spreading.
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The lack of cross-reactivity with other benzodiazepines is believed to be due to the molecular structure of tetrazepam. Photodermatitis and phototoxicity have also been reported. Occupational contact allergy can also develop from regularly handling tetrazepam. Airborne contact dermatitis can also occur as an allergy which can develop from occupational exposure.
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This reactivity is exploited in the regiospecific preparation of many di- and tri-substituted aromatic compounds. 2-Chlorotoluene for example can be prepared by chlorination of p-toluenesulfonic acid, followed by hydrolysis. The method is also useful for the preparation of 2,6-dinitroaniline and 2-bromophenol via phenol-2,4-disulfonic acid.
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Trans R Soc Trop Med Hyg 55: 63–68. Experimental work has demonstrated that SPONV can infect non-human primates. Due to its serological cross-reactivity and similar clinical presentations with ZIKV, SPONV may be maintained and transmitted in a sylvatic cycle to nonhuman primates and certain species of mosquitoes.
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Lithium at WebElements. Lithium is one of the few elements synthesized in the Big Bang. Lithium is the 33rd most abundant element on earth, occurring in concentrations of between 20 and 70 ppm by weight, but due to its high reactivity it is only found naturally in compounds.Kamienski et al.
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Analytical chemistry consists of classical, wet chemical methods and modern, instrumental methods. Classical qualitative methods use separations such as precipitation, extraction, and distillation. Identification may be based on differences in color, odor, melting point, boiling point, radioactivity or reactivity. Classical quantitative analysis uses mass or volume changes to quantify amount.
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Selenenic acid is protected by the protein environment from reactive groups within the protein. The mechanism of action is based on selenenic acid reacting with the amid or amine bond of another protein, forming a senyladmide bond, suggesting a role for this bond new bond in protecting the reactivity of GPX1.
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Ewen-style catalyst for producing syndiotactic polypropylene. Organozirconium compounds are organometallic compounds containing a carbon to zirconium chemical bond. Organozirconium chemistry is the corresponding science exploring properties, structure and reactivity of these compounds. Organozirconium compounds have been widely studied, in part because they are useful catalysts in Ziegler-Natta polymerization.
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Few inorganic fluorides are soluble in water without undergoing significant hydrolysis. In terms of its reactivity, fluoride differs significantly from chloride and other halides, and is more strongly solvated in protic solvents due to its smaller radius/charge ratio. Its closest chemical relative is hydroxide, since both have similar geometries.
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Mechanism of the base catalyzed alcoholysis of pentacoordinated phosphorus It can be understood from these experiments that the increased reactivity observed for hypervalent molecules, contrasted with analogous nonhypervalent compounds, can be attributed to the congruence of these species to the hypercoordinated activated states normally formed during the course of the reaction.
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Most of the suburb would have been dominated by a native pine forest according to accounts in Kraehenbuehl's book "Pre-European Vegetation of Adelaide". The soil of Clearview is brown and sandy to clay. The Keswich Clay deposit is present in the soil profile which is known for its reactivity.
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Benzil is a standard building block in organic synthesis. It condenses with amines to give diketimine ligands. A classic organic reaction of benzil is the benzilic acid rearrangement, in which base catalyses the conversion of benzil to benzilic acid. This reactivity is exploited in the preparation of the drug phenytoin.
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1,4-Dienes isomerize to the 1,3-dienes upon complexation. Fe(CO)5 reacts in dicyclopentadiene to form [Fe(C5H5)(CO)2]2, cyclopentadienyliron dicarbonyl dimer. This compound, called "Fp dimer" can be considered a hybrid of ferrocene and Fe(CO)5, although in terms of its reactivity, it resembles neither.
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Péloquin, K., & Lafontaine, M. (2010). Measuring empathy in couples: Validity and reliability of the Interpersonal Reactivity Index for couples. Journal of Personality Assessment, 92(2), 146-157. This was achieved by rewording some phrases used in the original, for example replacing references to "people" and "somebody" to be "my partner," etc.
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"Virtual Reality Cue Reactivity Assessment in Cigarette Smokers." CyberPsychology & Behavior 8.5 (2005): 487-92. For example, a smoker might have a habit of only smoking on his porch. Consequently, whenever he is near or around his porch, he connects it to smoking, and a craving is initiated by the mere proximity.
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Several popular approaches are employed in the creation of reactive programming languages. Specification of dedicated languages that are specific to various domain constraints. Such constraints usually are characterized by real-time, embedded computing or hardware description. Another approach involves the specification of general- purpose languages that include support for reactivity.
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Paints containing zinc oxide powder have long been utilized as anticorrosive coatings for metals. They are especially effective for galvanized iron. Iron is difficult to protect because its reactivity with organic coatings leads to brittleness and lack of adhesion. Zinc oxide paints retain their flexibility and adherence on such surfaces for many years.
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The presence of T. b. gambiense has been found separately in humans and livestock. This spurred a molecular study comparing serum reactivity of pigs, goats, and cows to human serum where notable similarities in all samples but especially in pig samples. Combined, these findings implicate a reverse zoonotic human to animal transmission.
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Organogallium compounds are of similar reactivity to organoindium compounds, less reactive than organoaluminium compounds, but more reactive than organothallium compounds.Greenwoood and Earnshaw, pp. 262–5 Alkylgalliums are monomeric. Lewis acidity decreases in the order Al > Ga > In and as a result organogallium compounds do not form bridged dimers as organoaluminum compounds do.
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Contraindications are severe respiratory or liver impairment and acute alcoholism. There are limited accounts of cross-reactivity with opioids, but there is a possibility. Serious central nervous system (CNS) and respiratory depression may also occur with concurrent use of CNS depressants, ingesting alcohol, or other CNS depressing factors while on buprenorphine/naloxone.
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On heating at 80 °C, DMTS slowly decomposes to a mixture of dimethyl di-, tri-, and tetrasulfides. The reactivity of DMTS is related to its weak sulfur-sulfur bond (ca. 45 kcal/mol). Dimethyl tetrasulfide, which is thermally more reactive than dimethyl trisulfide, has a still weaker (central) sulfur-sulfur bond (ca.
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PTSD was classified as an anxiety disorder in the DSM-IV, but has since been reclassified as a "trauma- and stressor-related disorder" in the DSM-5. The DSM-5 diagnostic criteria for PTSD include four symptom clusters: re-experiencing, avoidance, negative alterations in cognition/mood, and alterations in arousal and reactivity.
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Bicarbonate caused 10% of •OH scavenging. The reaction between bicarbonate and the •OH yields carbonate radical (•CO3), which is less reactive than •OH. In natural waters, •CO3 can reach a higher steady-state concentration than •OH because of its lower reactivity. The enhancement of PABA photolysis by bicarbonate is due to carbonate radicals.
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The term "Hawthorne effect" refers to the type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed. It was first observed in data from the Hawthorn Works collected by psychologist Elton Mayo and later reinterpreted by Henry A. Landsberger, who coined the term.
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They are located in the dermal papillae; due to their reactivity, they are primarily located in fingertips and lips. They respond in quick action potentials, unlike Merkel nerve endings. They are responsible for the ability to read Braille and feel gentle stimuli. Pacinian corpuscles determine gross touch and distinguish rough and soft substances.
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Catalytic triads perform covalent catalysis using a residue as a nucleophile. The reactivity of the nucleophilic residue is increased by the functional groups of the other triad members. The nucleophile is polarised and oriented by the base, which is itself bound and stabilised by the acid. Catalysis is performed in two stages.
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Distancing, an example of cognitive change, involves taking on an independent, third-person perspective when evaluating an emotional event. Distancing has been shown to be an adaptive form of self-reflection, facilitating the emotional processing of negatively valenced stimuli, reducing emotional and cardiovascular reactivity to negative stimuli, and increasing problem-solving behavior.
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A mnemonic is a memory aid used to improve long term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics. This article contains the list of certain mnemonics in chemistry.
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It therefore produces reactivity comparable to metallocene catalysts which are also believed to be homogeneous, single sited catalysts. The catalytic process is assumed to proceed in much of the same way as metallocene based catalysts, as the chemistry is thought to occur primarily with the metal centre and not through the bulky ligands.
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V. Aina, G. Lusvardi, G. Malavasi, L. Menabue, C. Morterra, Fluoride-containing bioactive glasses: surface reactivity in simulated body fluids, Acta Biomaterialia 5 (2009) 3548–3562.Zhang, J., Wang, M., Cha, JM. & Mantalaris, A. (2009). The incorporation of 70s bioactive glass to the osteogenic differentiation of murine embryonic stems cells in 3D bioreactors.
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During the reaction, the intensity of emotion that is brought on by the stimulus will also determine the nature and intensity of the behavioral response. Individuals with higher levels of emotional reactivity may be prone to anxiety and aggression, which illustrates the implications of appropriate emotional reaction in the fight or flight response.
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Belite is the mineral in Portland cement responsible for development of "late" strength. The other silicate, alite contributes "early" strength, due to its higher reactivity. Belite reacts with water (roughly) to form calcium silicate hydrates (C-S-H) and portlandite (Ca(OH)2) according to the reaction: \underbrace_ + \underbrace_ -> 3 CaO . 2 SiO2.
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Organoneptunium chemistry is the chemical science exploring the properties, structure and reactivity of organoneptunium compounds, which are organometallic compounds containing a carbon to neptunium chemical bond. Several such compounds exist even though the element itself, neptunium, is man-made and highly radioactive: tricyclopentadienylneptunium-chloride, tetrakis(cyclopentadienyl)neptunium(IV) and neptunocene Np(C8H8)2.
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Organoplatinum compounds are implicated in the Shilov system for the conversion of methane into methyl chloride. Strenuous efforts have been made, thus far unsuccessfully, to extend this reactivity to practical methods for functionalizing methane. For example, platinum complexes of bipyrimidine catalyze the conversion of methane, oxygen, and sulfur trioxide into methyl bisulfate.
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Other HCPs may be very similar to a human protein and may induce an immune response with cross reactivity against the human protein or the drug substance protein. The exact consequences of HCPs for the individual patient is uncertain and difficult to determine with the current analytical methods applied in biopharmaceutical approval.
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The plant began operations in November 1961. It had a net power output of 23.5 MW-thermal, and its purposes were primarily to research various aspects of nuclear-reactor technology and to train personnel. Major areas of research for the plant were the chemical control of reactivity and the use of MOX fuel.
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DNA‐templated organic synthesis (DTS) is a way to control the reactivity of synthetic molecules by using nature's molarity‐based approach. Historically, DTS was used as a model of prebiotic nucleic acid replication. Now however, it is capable of translating DNA sequences into complex small‐molecule and polymer products of multistep organic synthesis.
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However its reactivity and incompatibility with many materials hindered such use. Coating of nitronium perchlorate particles with ammonium nitrate, prepared in situ by passing of dry ammonia gas over the particles, was investigated and a patent was awarded.Diebold, James P. (17 April 1973). Encapsulation of Nitronium Perchlorate Employing Ammonia to Form Ammonium Perchlorate.
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The method exploits the reactivity of nitrous acid derived from acidification of nitrite. Nitrous acid selectively reacts with aromatic amines to give diazonium salts, which in turn couple with a second reagent to give the azo dye. The detection limit is 0.02 to 2 μM. Methods have been highly adapted to biological samples.
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Above is the second most common molecule after in gaseous sulfur. In liquid sulfur the molecule is not common until the temperature is high, such as . However, small molecules like this contribute to most of the reactivity of liquid sulfur. has an absorption peak of (violet) with a tail extending into blue light.
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They remained friends after divorcing in 1973. "I could speak to parts of Ryan like temper and volatility and reactivity, but I deeply know his goodness", Taylor- Young said. O'Neal was in a relationship with actress Farrah Fawcett from 1979 to 1997. The relationship was tumultuous due to his infidelity and volatile behavior.
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Beyond the genome, the Snyder lab was also the first to set up protein and proteome microarrays for the large-scale characterization of protein function and antibody reactivity (21,22) . They demonstrated many novel biological activities of protein kinases and other yeast proteins and showed they can be useful for autoantibody profiling (23) .
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Finally, across many studies, Puhl and Suh (2015) also found that experiencing weight stigma is related to many physiological consequences as well, including increased blood pressure, augmented cortisol reactivity, elevated oxidative stress, impaired glycemic control/elevated HbA1c, and increased systemic inflammation, all of which have notable consequences for physical health and disease.
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There are many ways that size can affect the toxicity of a nanoparticle. For example, particles of different sizes can deposit in different places in the lungs, and are cleared from the lungs at different rates. Size can also affect the particles' reactivity and the specific mechanism by which they are toxic.
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MTSL is attached to proteins by reaction with thiol groups. The reaction exploits standard reactivity of thiosulfate esters. Sulfinic acid (CH3SO2H) is the leaving group: :RSO2S-nitroxide + protein-SH → protein-S-S-nitroxide + RSO2H The heterodisulfide bond to the cysteine residue is robust, enabling site-directed spin labelling.Kenyon, G.L. and Bruice, T.W. (1977).
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Norbornene or norbornylene or norcamphene is a highly strained bridged cyclic hydrocarbon. It is a white solid with a pungent sour odor. The molecule consists of a cyclohexene ring with a methylene bridge between carbons 1 and 4. The molecule carries a double bond which induces significant ring strain and significant reactivity.
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Sleep deprivation amplifies reactivity of brain reward networks, biasing the appraisal of positive emotional experiences. Journal of Neuroscience, 31(12), 4466-4474. doi:10.1523/jneurosci.3220-10.2011 Deficient sleep, both in the form of sleep deprivation and restriction, adversely impacts emotion generation, emotion regulation, and emotional expression.Palmer, C. A., & Alfano, C. A. (2016).
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Diborane and its variants are central organic synthesis reagents for hydroboration, whereby alkenes add across the B-H bonds to give trialkylboranes. Diborane is used as a reducing agent roughly complementary to the reactivity of lithium aluminium hydride. The compound readily reduces carboxylic acids to the corresponding alcohols, whereas ketones react only sluggishly.
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The pyrimidine ring resists electrophilic substitution, although the 4-position is more reactive than the 2-position. In comparison, the benzene ring is more susceptible to electrophilic substitution. The ring position order of reactivity is 8 > 6 > 5 > 7. 2- and 4-halo derivatives of quinazoline undergo displacement by nucleophiles, such as piperidine.
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In electrophilic amination, the amine as the nucleophile react with another the organic compound as the electrophile. This sense of reactivity may be reversed for some electron-deficient amines, including oxaziridines, hydroxylamines, oximes, and other N–O substrates. When the amine is used as an electrophile, the reaction is called electrophilic amination.
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Unlike the other isomers of nitrochlorobenzene, the meta isomer is not activated to nucleophilic substitution at the chlorine center. However, 3-nitrochlorobenzene has other interesting reactivity. 3-Nitrochlorobenzene can be reduced to 3-chloroaniline with Fe/HCl mixture, the Bechamp reduction. Electrophilic aromatic substitution is possible on 3-nitrochlorobenzene, yielding many possible products.
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This category encompasses the simplest approach of coupling an electrophile with low intrinsic reactivity to a noncovalent binding moiety which frequently mimics the natural substrate. Key to this designation is that the reactivity of the electrophile is not altered by the enzyme and that the noncovalent binding moiety serves to increase the presence and lifetime of the electrophile in the active site (effective molarity). The weakly reactive group may react with functional groups outside of the active site or on other proteins but the selectivity is conferred by the noncovalent binding moiety. Kinetic signatures of this type of inhibitor can be found in saturation because of the covalent reaction (kinact) becomes the rate limiting step at high concentrations of inhibitor.
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Some laboratory research demonstrates correlations between psychopathy and atypical responses to aversive stimuli, including weak conditioning to painful stimuli and poor learning of avoiding responses that cause punishment, as well as low reactivity in the autonomic nervous system as measured with skin conductance while waiting for a painful stimulus but not when the stimulus occurs. While it has been argued that the reward system functions normally, some studies have also found reduced reactivity to pleasurable stimuli. According to the response modulation hypothesis, psychopathic individuals have also had difficulty switching from an ongoing action despite environmental cues signaling a need to do so. This may explain the difficulty responding to punishment, although it is unclear if it can explain findings such as deficient conditioning.
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Herbert C. Brown did not believe that it was necessary to invoke a new type of bonding in stable intermediates to explain the interesting reactivity of the 2-norbornyl cation. Criticizing many chemists for disregarding past explanations of reactivity, Brown argued that all of the aforementioned information about the 2-norbornyl cation could be explained using simple steric effects present in the norbornyl system. Given that an alternative explanation using a rapidly equilibrating pair of ions for describing the 2-norbornyl cation was valid, he saw no need to invoke a stable, non-classical depiction of bonding. Invoking stable non- classical ions was becoming commonplace; Brown felt that this was not only unwarranted but also counterproductive for the field of chemistry as a whole.
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Strelau was the author of the Regulative Theory of Temperament (RTT) that concentrates on formal aspects of behavior, comprising energetic and temporal characteristics composed of such traits as: sensory sensitivity, emotional reactivity, endurance and activity (energetic aspect), briskness and perseverance (temporal combustion). The Formal Characteristics of Behavior – Temperament Inventory (FCB-TI), developed by Strelau and Bogdan Zawadzki and adapted to many language versions allows for measuring these traits. A lot of empirical evidence has been collected by Strelau and his collaborators demonstrating that heritability explains about 40 percent of the variance in RTT temperament traits. In many studies, conducted among others on victims of disasters and catastrophes it came out that such traits as emotional reactivity, perseverance and activity are significant moderators of psychological consequences (e.g.
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TRIGA is a swimming pool reactor that can be installed without a containment building, and is designed for research and testing use by scientific institutions and universities for purposes such as undergraduate and graduate education, private commercial research, non- destructive testing and isotope production. The TRIGA reactor uses uranium zirconium hydride (UZrH) fuel, which has a large, prompt negative fuel temperature coefficient of reactivity, meaning that as the temperature of the core increases, the reactivity rapidly decreases. Because of this unique feature, it has been safely pulsed at a power of up to 22,000 megawatts.TRIGA® Nuclear Reactors General Atomics The hydrogen in the fuel is bound in the uranium zirconium hydride crystal structure with a vibrational energy of 0.14eV.
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Infusion of adrenaline well within the physiological range suppresses human airway hyper-reactivity sufficiently to antagonize the constrictor effects of inhaled histamine. A link between the sympathetic nervous system and the lungs was shown in 1887 when Grossman showed that stimulation of cardiac accelerator nerves reversed muscarine-induced airway constriction. In experiments in the dog, where the sympathetic chain was cut at the level of the diaphragm, Jackson showed that there was no direct sympathetic innervation to the lung, but that bronchoconstriction was reversed by release of adrenaline from the adrenal medulla. An increased incidence of asthma has not been reported for adrenalectomized patients; those with a predisposition to asthma will have some protection from airway hyper-reactivity from their corticosteroid replacement therapy.
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Endophenotypic Factors have been examined by Obradovic, Bush, Stamperdahl, Adler and Boyce's (2010). They investigated associations between childhood adversity and child adjustment in 338 5-year olds. Children with high cortisol reactivity were rated by teachers as least prosocial when living under adverse conditions, but most prosocial when living under more benign conditions (and in comparison to children scoring low on cortisol reactivity). Regarding characteristics of the category of Phenotypic Factors, Pluess and Belsky (2009) reported that the effect of child care quality on teacher-rated socioemotional adjustment varied as a function of infant temperament in the case of 761 4.5-year olds participating in the NICHD Study of Early Child Care and Youth Development (NICHD Early Child Care Research Network, 2005).
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Chaudret synthesized the first bis(dihydrogen) complex and demonstrated its high reactivity, particularly for the activation of C-H, Si-H and more generally of poorly reactive bonds. He has also been interested in the spectroscopic properties of these species, in particular the quantum exchange of protons in the coordination sphere of transition metals. Chaudret developed a method for synthesizing large aggregates (from 50 metal atoms to several tens of thousands of atoms). The method has enabled the synthesis of nanoparticles of controlled size, shape, surface and assembly of a wide variety of elements, alloys and semiconductor compounds.K. Philippot, B. Chaudret, « Organometallic Approach to the Synthesis and Surface Reactivity of Noble Metal Nanoparticles », Compte-Rendus Acad Sciences, 2003, 6, p.
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Its ultraviolet transparency UV cutoff, low viscosity and low chemical reactivity make it a popular choice for high-performance liquid chromatography (HPLC). Acetonitrile plays a significant role as the dominant solvent used in the manufacture of DNA oligonucleotides from monomers. Industrially, it is used as a solvent for the manufacture of pharmaceuticals and photographic film.
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The structure is thus similar to that of sarin, which has only a smaller hydrocarbon group attached (isopropyl). Because of the similarity between the chemical structures, the reactivity of the two compounds is almost the same. Soman and sarin will both react using the phospho oxygen group, which can bind to amino acids like serine.
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The Li-arene reacted with water or deuterium to produce the dehalogenated product.Ramón, D.; Yus, M. Masked lithium bishomoenolates: Useful intermediates in organic synthesis, J. Org. Chem. 1991, 56, 3825-3831.Guijarro, A.; Ramón, D.; Yus, M. Naphthalene- catalysed lithiation of functionalized chloroarenes: regioselective preparation and reactivity of functionalized lithioarenes, Tetrahedron, 1993, 49, 469-482.
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The biggest problem with these reagents are that the reactivity has not been well documented. It is believed that the TiCl4 acts as a mediator in the reaction. Nysted reagent can methylenate different carbonyl groups in the presence of different mediators. For example, in the presence of BF3•OEt2, the reagent will methylenate aldehydes.
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This depends upon a relationship between the specific surface area and the resistance to gas-flow of a porous bed of powder. The method is simple and quick, and yields a result that often correlates well with the chemical reactivity of a powder. However, it fails to measure much of the deep surface texture.
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Unlike acid halides, however, anhydrides do not react with Gilman reagents. The reactivity of anhydrides can be increased by using a catalytic amount of N,N-dimethylaminopyridine, or DMAP. Pyridine can also be used for this purpose, and acts via a similar mechanism. DMAP activates anhydrides towards nucleophilic substitution by creating a better leaving group.
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They suggested that the reaction proceeds by a radical mechanism. They predict that HInCl adds to alkyne by radical addition in a Z geometry. It does not isomerized to E geometry because of low reactivity of radical InCl2 with intermediate complex (no second addition). If second addition occurs then isomerization will occur through diindium intermediate.
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Metal oxo complexes are intermediates in many metal-catalyzed oxidation reactions. Oxygen-atom transfer is common reaction of particular interest in organic chemistry and biochemistry. Some metal-oxos are capable of transferring their oxo ligand to organic substrates. One such example of this type of reactivity is from and enzyme super-family Molybdenum oxotransferase.
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It grows as a mass of interlocking needles that provide the strength of the hydrated cement system. High alite reactivity is desirable in Portland cement manufacture, and this is achieved by retaining, as far as possible, high temperature polymorphs, in crystals that are small, distorted and highly defective. Defects provide sites for initial water attack.
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Burnable neutron absorbers within the fuel and control rod inventory are used to suppress hot excess reactivity. Cold shut-down was accomplished with control rod insertion (as in BWRs). The mPower was designed to produce superheated steam and would not require steam separators and dryers prior to admitting steam into the high-pressure turbine.
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1995, 117, 6210. Substituted allylstannanes may create one or two new stereocenters, often with a very high degree of stereocontrol. (1)441px Advantages: Organostannanes are known for their stability, ease of handling, and selective reactivity. Chiral allylstannanes often react with great stereoselectivity to give single diastereomers, and models explaining the sense of selectivity are reliable.
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The smooth muscle–like cells of AMLs are morphologically and immunohistochemically similar to LAM cells, including reactivity with antibodies directed against actin, desmin, vimentin, and HMB-45 as well as estrogen and progesterone receptors. Unlike the dilated airspaces in emphysema, the cystic spaces found in LAM may be partially lined with hyperplastic type II cells.
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PLoS Neglected Tropical Diseases. 8 (1): e2636 It is part of the Spondweni serogroup which also contains the Zika virus. However, in certain Spondweni virus cases, signs and symptoms can appear as early as three days after infection. Both of these viruses in the Spondweni serogroup have serological cross-reactivity and very similar clinical presentations.
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Maternal deprivation can be caused by the abandonment by a nurturing parent at a young age. In rodents or nonhuman primates, this leads to a higher vulnerability for stress-related illness. Research suggests that environmental enrichment can reverse the effects of maternal separation on stress reactivity, possibly by affecting the hippocampus and the prefrontal cortex.
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Berridge is known for his work on the brain systems for pleasure (“liking”).Berridge, K.C. Pleasures of the Brain. Brain Cogn. 2003 Jun;52(1):106-28. Using an assay for “liking” called Taste Reactivity Analysis developed by taste researchers, Berridge measures facial palatability responses to tastes, which are similar between rodents, primates and humans.
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Mills completed his MChem in 2004 at Cardiff University where he finished his masters project with Prof. Cameron Jones. Upon graduation, he continued to read for his Doctor of Philosophy degree with Prof. Jones on Investigations into the Reactivity of an Anionic Gallium(I) N-Heterocyclic Carbene Analogue and successfully gained his PhD in 2007.
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Due to their extreme reactivity, arynes must be generated in situ. Typical of other reactive intermediates, benzyne must be trapped, otherwise it dimerises to biphenylene. Early routes to benzyne involved dehydrohalogenation of aryl halides: center Such reactions require strong base and high temperatures. Ortho-disubstituted arenes serve as precursors to benzynes under milder conditions.
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PPh3 is widely used in organic synthesis. The properties that guide its usage are its nucleophilicity and its reducing character. The nucleophilicity of PPh3 is indicated by its reactivity toward electrophilic alkenes, such as Michael-acceptors, and alkyl halides. It is also used in the synthesis of biaryl compounds, such as the Suzuki reaction.
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When tantalum enrichment is observed, it is probably due to loss of more water-soluble elements in aerosols in the clouds. Pollution linked to human use of the element has not been detected. Tantalum appears to be a very conservative element in biogeochemical terms, but its cycling and reactivity are still not fully understood.
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2,4-Dinitroaniline can be prepared by reaction of 1-chloro-2,4-dinitrobenzene with ammonia. It can be also prepared by the electrophilic aromatic substitution of aniline. Direct nitration should not be used due to the reactivity of aniline. (i.e. It can be protonated to anilinium or oxidized easily.) Instead the acetyl protection should be used.
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Indirect observation can be used if one wishes to be entirely unobtrusive in their observation method. This can often be useful if a researcher is approaching a particularly sensitive topic that would be likely to elicit reactivity in the subject. There are also potential ethical concerns that are avoided by using the indirect observational method.
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Clinical trials involving participants with multiple food allergies has enabled determination of associations and cross-reactivities of different food allergens. These studies have further assisted with epitope mapping, identification, and characterization of allergenic components of foods that induce clinical reactivity. Data from these studies may, in the future, enable therapeutic targets for food allergies.
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Gujar, N., Yoo, S., Hu, P., & Walker, M. P. (2011). Sleep Deprivation Amplifies Reactivity of Brain Reward Networks, Biasing the Appraisal of Positive Emotional Experiences. Journal of Neuroscience, 31(12), 4466-4474. doi:10.1523/jneurosci.3220-10.2011 One night of sleep deprivation caused participants to judge neutral images more negatively than non sleep deprived participants.
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Because of the hazards associated with their use, few azides are used commercially although they exhibit interesting reactivity for researchers. Low molecular weight azides are considered especially hazardous and are avoided. In the research laboratory, azides are precursors to amines. They are also popular for their participation in the "click reaction" and in Staudinger ligation.
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Traces of many aldehydes are found in essential oils and often contribute to their favorable odors, e.g. cinnamaldehyde, cilantro, and vanillin. Possibly because of the high reactivity of the formyl group, aldehydes are not common in several of the natural building blocks: amino acids, nucleic acids, lipids. Most sugars, however, are derivatives of aldehydes.
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Reactive synthesis (or temporal synthesis) is the field of computer science that studies automatic generation of state machines (e.g. Moore machines) from high-level specifications (e.g. formulas in linear temporal logic). "Reactivity" highlights the fact that the synthesized machine interacts with the user, reading an input and producing an output, and never stops its operation.
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The first preparation of a münchnone derivative was reported in 1958 by Lawson & Miles by cyclodehydration of 2-pyridone-N-acetic acid with acetic anhydride.Lawson, A.; Miles, D. H. Chem. Ind. (London) 1958, 461. The azomethine ylide reactivity of münchnones, and their reaction with alkynes in the synthesis of pyrroles, was first published by Huisgen et al.
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The trend continues this way until column 18, which has six p-orbital electrons. The block is a stronghold of the octet rule in its first row, but elements in subsequent rows often display hypervalence. The p-block elements show variable oxidation states usually differing by multiples of two. The reactivity of elements in a group generally decreases downwards.
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The reactivity order is (CH3)3C- > (CH3)2CH- > CH3CH2- > CH3-. Unimolecular Elimination Reaction Coordinate Furthermore, studies describe a typical kinetic resolution process that starts out with two enantiomers that are energetically equivalent and, in the end, forms two energy-inequivalent intermediates, referred to as diastereomers. According to Hammond's postulate, the more stable diastereomer is formed faster.
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This reactivity decreases until a person enters adolescence, where it increases dramatically at puberty. Other functional and structural differences between male and female amygdalae have been observed. Subjects' amygdala activation was observed when watching a horror film and subliminal stimuli. The results of the study showed a different lateralization of the amygdala in men and women.
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DpgC performs this oxidation in absence of any iron, heme, flavin, or pterin cofactors. Chen et al suggest the following reaction mechanism to explain the reactivity of DpgC.Chen, H., Tseng, C. C., Hubbard, B. K., Walsh, C. T. "Glycopeptide antibiotic biosyntehsis: Enzymatic assembly of the dedicated amino acid monomy (S)-3,5-dihydroxyphenylglycine." PNAS, 2001, 98 (26), 14901-14906.
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Reagents with bulky R groups such as lithium diisopropylamide (LDA) and lithium bis(trimethylsilyl)amide (LiHMDS) are often sterically hindered for nucleophilic addition, and are thus more selective toward deprotonation. Lithium dialkylamides (LiNR2) are widely used in enolate formation and aldol reaction. The reactivity and selectivity of these bases are also influenced by solvents and other counter ions.
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The alkene portion of the molecule is reactive in many ways. It is prone to polymerization, leading to formation of polyvinyl ethers. Polymerization is typically initiated with Lewis acids such as boron trifluoride. This mode of reactivity is analogous to the way vinyl acetate and vinyl chloride can be polymerized to form polyvinyl acetate and polyvinyl chloride, respectively.
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Combined with the reactivity system, Vue is able to calculate the minimal number of components to re-render and apply the minimal amount of DOM manipulations when the app state changes. Vue users can use template syntax or choose to directly write render functions using JSX. Render functions allow application to be built from software components.
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The weakly coordinated Ge(II) cations are Lewis acids. Due to this weak coordination, such Ge(II) crown ether complexes could be useful for the preparation of other germanium compounds. Bandyopadhyay et al. have investigated the reactivity of a GeOTf+ [15]crown-5 complex, and found that the weakly coordinating triflate could be exchanged for H2O or NH3.
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Because of this high reactivity, caesium metal is classified as a hazardous material. It is stored and shipped in dry, saturated hydrocarbons such as mineral oil. It can be handled only under inert gas, such as argon. However, a caesium-water explosion is often less powerful than a sodium-water explosion with a similar amount of sodium.
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The reduction of α-halo ketones generates a variety of product structures that may exhibit unique substitution patterns and reactivity. For instance, reduction of α,α'-dihalo ketones leads to 2-oxyallyl metal complexes, which participate in [4+3] and [3+2] cycloaddition reactions as the 2π component.Rigby, J.; Pigge, C. Org. React. 1997, 51, 351.
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Sesame can trigger the same allergic reactions, including anaphylaxis, as seen with other food allergens. Sesame oil can also be an allergen source of the allergy-triggering proteins. Prevalence is higher in people who have allergic reactions to other foods. A cross-reactivity exists between sesame allergens and those of several other nuts or seeds, particularly peanuts.
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Example of organogelator molecules. Gelation mechanism greatly influences the typical organogel properties. Since precursors with multiple functional groups polymerize into networks of covalent C-C bonds (on average 85 kcal/mol), networks formed by self-assembly, which relies on secondary forces (generally less than 10 kcal/mol), are less stable.Ege, S. N. Organic Chemistry Structure and Reactivity, 5th ed.
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In this compound class, the cyclopentadienyl ligands of the ferrocene are connected by one or more bridging groups. This hinders the rotation of the cyclopentadienyl ligands against one another and the reactivity of the complex with respect to the parent compound ferrocene is altered. A variety of organic and inorganic groups is suitable as bridging group.
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Finely powdered lead, as with many metals, is pyrophoric, and burns with a bluish-white flame. Fluorine reacts with lead at room temperature, forming lead(II) fluoride. The reaction with chlorine is similar but requires heating, as the resulting chloride layer diminishes the reactivity of the elements. Molten lead reacts with the chalcogens to give lead(II) chalcogenides.
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Diketones with two methylene groups separating the carbonyl groups, also called γ-diketones, typically coexist with their enol tautomers. The preeminent member is acetonylacetone. 1,4-Diketones are useful precursors to heterocycles via the Paal–Knorr synthesis, which gives pyrroles: :Dehydration of 1,4-diketones gives furans. This reactivity is the basis of the neurotoxicity of γ-diketones.
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Pentaborane(9) is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel. Like many of the smaller boron hydrides, pentaborane is colourless, diamagnetic, and volatile.
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Small catalyst particles have the highest possible relative surface area and high reaction temperature, both factors that generally increase the reactivity of a catalyst. However, these factors are also the circumstances under which sintering occurs. Specific materials may also increase the rate of sintering. On the other hand, by alloying catalysts with other materials, sintering can be reduced.
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Avoidance responses may involve the absence of expected activation or emotional reactivity as well as the use of avoidance mechanisms (e.g., substance use, effortful avoidance of cues associated with the event, dissociation). In addition to monitoring activation and avoidance responses, clinicians carefully observe the individual's strengths or difficulties with affect regulation (i.e., affect tolerance and affect modulation).
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The reactivity order is (CH3)3C- > (CH3)2CH- > CH3CH2- > CH3-. Unimolecular Elimination Reaction Coordinate Furthermore, studies describe a typical kinetic resolution process that starts out with two enantiomers that are energetically equivalent and, in the end, forms two energy-inequivalent intermediates, referred to as diastereomers. According to Hammond's postulate, the more stable diastereomer is formed faster.
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The O—F bond of hypofluorites is relatively weak. For trifluoromethyl hypofluorite (CF3OF), it was estimated to be . The ability of trifluoromethyl hypofluorite to transfer fluorine to alkyl radicals was notably demonstrated by reacting independently generated ethyl radicals from ethene and tritium in presence of CF3OF. The high reactivity of hypofluorites has limited their application to selective radical fluorination.
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Rauhut-Currier reaction is a reaction of activated alkene and a Michael acceptor, not an aldehyde or an imine. It is also called a vinylogous MBH reaction. Because Rauhut-Currier reaction often couple two activated alkenes, there have been problems with selectivity. Intramolecular Rauhut-Currier reaction has been employed by the virtue of improved reactivity and selectivity.
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From left to right: chlorine, bromine, and iodine at room temperature. Chlorine is a gas, bromine is a liquid, and iodine is a solid. Fluorine could not be included in the image due to its high reactivity, and astatine and tennessine due to their radioactivity. Approximately six million metric tons of the fluorine mineral fluorite are produced each year.
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Normally, the heat flux from neutron and gamma heating at the surface of the capsule is limited to 74,000 Btu/h-ft² (2.3 x 105 W/m²). Furthermore, the neutron poison content of the facility load is limited such that the reactor cannot be tripped by a significant reactivity change upon insertion and removal of the samples.
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In contrast the magnesium compounds have more covalent and therefore less reactive metal-ligand bonds. Additionally, the whole magnesium amide complex is stabilized by LiCl. This is why Turbo-Hauser bases display a higher functional group tolerance and a much greater chemoselectivity at high and low temperatures. iPr2NMgCl·LiCl can show a different reactivity compared to TMPMgCl·LiCl.
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VCH–Lavoisier: Paris. p. 9. The reactivity of NaBH4 can be enhanced or augmented by a variety of compounds. Oxidation with iodine in tetrahydrofuran gives the borane–tetrahydrofuran complex, which can reduce carboxylic acids. Likewise, the NaBH4-MeOH system, formed by the addition of methanol to sodium borohydride in refluxing THF, reduces esters to the corresponding alcohols.
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Depending on synthesis conditions, the first phase to crystallize may be the metastable anatase phase, which can then be converted to the equilibrium rutile phase through thermal treatment. The physical properties of rutile are often modified using dopants to impart improved photocatalytic activity through improved photo-generated charge carrier separation, altered electronic band structures and improved surface reactivity.
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It is possible to modify Tebbe's reagent through the use of different ligands. This can alter the reactivity of the complex, allowing for a broader range of reactions. For example, cyclopropanation can be achieved using a chlorinated analogue.Unusual Ambiphilic Carbenoid Equivalent in Amide Cyclopropanation Kuo-Wei Lin, Shiuan Yan, I-Lin Hsieh, and Tu-Hsin Yan Org. Lett.
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The main benefit of shadow IT is the increased reactivity. The host department has direct power over its shadow IT resources, as opposed to central ones. Also, alignment between departments, a time- consuming and sometimes impossible task, is avoided. Shadow IT systems are an important source of innovation, and shadow systems may become prototypes for future central IT solutions.
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Bicarbonate is activated by the addition of ATP, increasing the reactivity of bicarbonate. Once bicarbonate is activated, the biotin portion of MCC performs nucleophilic attack on the activated bicarbonate to form enzyme-bound carboxybiotin. The carboxybiotin portion of MCC can then undergo nucleophilic attack transferring the carboxyl group to the substrate, 3-methylcrotonyl CoA, to form 3-methylglutaconyl CoA.
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Paul Fenter is a senior physicist and group leader for interfacial processes at the U.S. Department of Energy’s (DOE) Argonne National Laboratory. He is also the director of the Center for Electrochemical Energy Science (CEES), a DOE Energy Frontier Research Center, where he oversees research to understand interfacial reactivity and complex reaction pathways in lithium-ion battery systems.
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J Neurosci Nurs. 2005;37:34–40.Chen J, Gombart Z, Rogers S, Gardiner S, Cecil S, Bullock R. Pupillary reactivity as an early indicator of increased intracranial pressure: the introduction of the neurological pupil index. Surg Neurol Int. 2011;2:82.Du R, Meeker M, Bacchetti P, Larson M, Holland M, Manley G. Evaluation of the portable infrared pupillometer. Neurosurgery.
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If there is a unilateral small pupil with normal reactivity to light, it is unlikely that a neuropathy is present. However, if accompanied by ptosis of the upper eyelid, this may indicate Horner's syndrome. If there is a small, irregular pupil that constricts poorly to light, but normally to accommodation, this is an Argyll Robertson pupil.
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A dollar symbol is used as unit of reactivity for a nuclear reactor, 1$ being the threshold of slow criticality, meaning a steady reaction rate, while 2$ is the threshold of prompt criticality, which means a nuclear excursion or explosion. The dollar sign was used as a letter in the Turkmen alphabet from 1993 to 1999.
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It was however, inferior in quality, and cost-prohibitive to produce. Adams was concerned because two processes showed an equal potential to emerge as the preferred manner of production. One depended on distilling an additive for reactivity, while the other used a petroleum-based reagent. Adams was hopeful that rubber would come to be polymerized by petrochemical means.
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"Reactivity of Formic Acid on Calcium Carbonate Single Particle and Single Crystal Surfaces: Effect of Adsorbed Water". Microscopy and Microanalysis (Cambridge University Press) 12(Suppl 2): 796-797. :CaCO3 \+ 2CH2O2 → Ca(HCOO)2 \+ H2O + CO2 Calcium carbonate and sulfuric acid chemical reaction occurs as follows:Casiday, R. and Frey, R. Rain Inorganic Reactions Experiment. Department of Chemistry, Washington University.
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The broad-spectrum effectiveness of most bleaches is due to their general chemical reactivity against organic compounds, rather than the selective inhibitory or toxic actions of antibiotics. They irreversibly denature or destroy many proteins, making them extremely versatile disinfectants. Hypochlorite bleaches in low concentration were also found to attack bacteria by interfering with heat shock proteins on their walls.
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His doctoral research was on the solubility and reactivity of iodine in carbonic acid in the gas phase. His doctoral research also enabled him to become experienced in analytical chemistry. Strassmann's doctoral advisor was Professor Hermann Braune. Subsequently, Strassmann received a partial scholarship to the Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem, beginning in 1929.
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A reacting system is always governed by temperature - in any form. This means that the temperature of the liquid components has a strong influence on the reactivity. So do the temperatures inside the tool. To ensure that one side has an excellent surface finish, the temperature on that side needs to be higher than on the core side.
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The coolant salt in the reactor tank is a sodium zirconium fluoride mixture. The zirconium is not nuclear-grade and still contains ~2% hafnium. This has minimal effect on core reactivity but makes the coolant salt low-cost and a highly effective neutron shield. One metre of coolant reduces neutron flux by four orders of magnitude.
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Lithium borohydride is a stronger reducing agent than sodium borohydride. In mixtures of methanol and diethyl ether, lithium borohydride is able to reduce esters to alcohols and primary amides to amines. In contrast, these substrates are unaffected by sodium borohydride. The enhanced reactivity is attributed to the polarization of the carbonyl substrate by complexation to the lithium cation.
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Material Safety Data Sheet. As of 2013 2-butoxyethanol has been removed from Simple Green all-purpose cleaner, and has an NFPA/HMIS rating of 0/minimal for Health, Fire, Reactivity, and Special. The company stands by its safety, stating that it is backed by over $3 million in safety testing. Its main competitors are Lysol and Clorox.
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NHSis insert into σ bonds to form terminal silane-like products, NHSi-NHSi disalane bridges, or oxo-bridged NHSi siloxanes. Alcohols react with Si(II) to form exclusively the silyl ether. With water, two NHSis will insert to each of the O-H bonds to form a siloxane. A more varied reactivity is seen with haloalkanes.
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Due to the heterogeneity of the reaction mixture, yields are contingent on the rate of stirring, which can pose a problem for larger scale (i.e. process-scale) reactions. Additionally, Weix and coworkers found that reactivity is also contingent on the source and size of the zinc dust. Tetrakis(dimethylamino)ethylene (TDAE) can also function as a single-electron reductant.
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Despite the low solubility of O3F2 in liquid oxygen, it has been shown to be hypergolic with most rocket propellant fuels. The mechanism involves the boiling off oxygen from the solution containing O3F2, making it more reactive to have a spontaneous reaction with the rocket fuel. The degree of reactivity is also dependent on the type of fuel used.
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Adding 2% of calcium by weight to magnesium alloy AM60 results in the non-combustible magnesium alloy AMCa602. The higher oxidation reactivity of calcium causes a coat of calcium oxide to form before magnesium ignites. The ignition temperature of the alloy is elevated by 200–300 K. An oxygen-free atmosphere is not necessary for machining operations.
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According to the long-standing Diathesis-stress model, people differ in their response to adverse experiences and environments, with some individuals more negatively affected by environmental stressors than others . The model proposes that such differences in response result from the presence of “vulnerability” factors, which include psychological (e.g., impulsive personality), physiological (e.g., high physiologically reactivity) and genetic factors (e.g.
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87(2): p. 374-84.. More specifically, a high cortisol response in children was associated with more positive cognitive development when family income was high, but with reduced cognitive development when family income was low. In contrast, family income was less relevant for the cognitive development of children who displayed low physiological reactivity (i.e., a low cortisol response).
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Although historically frequently used, the term "activated" microglia should be replaced by "reactive" microglia. Indeed, apparently quiescent microglia are not devoid of active functions and the "activation" term is misleading as it tends to indicate an "all or nothing" polarization of cell reactivity. The marker Iba1, which is upregulated in reactive microglia, is often used to visualize these cells.
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In addition, alkanes have been shown to interact with, and bind to, certain transition metal complexes in C–H bond activation reactions. In highly branched alkanes, the bond angle may differ significantly from the optimal value (109.5°) to accommodate bulky groups. Such distortions introduce a tension in the molecule, known as steric hindrance or strain. Strain substantially increases reactivity.
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Adding the atomisation and first ionisation energies gives a quantity closely related to (but not equal to) the activation energy of the reaction of an alkali metal with another substance. This quantity decreases going down the group, and so does the activation energy; thus, chemical reactions can occur faster and the reactivity increases down the group.
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Aluminium (symbol Al) or aluminum (American English) is a silvery white member of the boron group of chemical elements and a p-block metal classified by some chemists as a post-transition metal.Huheey JE, Keiter EA & Keiter RL 1993, Principles of Structure & Reactivity, 4th ed., HarperCollins College Publishers, , p. 28 It is not soluble in water under normal circumstances.
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Because of the electronegative nitrogen in the pyridine ring , the molecule is relatively electron deficient. It, therefore, enters less readily into electrophilic aromatic substitution reactions than benzene derivatives. Correspondingly pyridine is more prone to nucleophilic substitution, as evidenced by the ease of metalation by strong organometallic bases. The reactivity of pyridine can be distinguished for three chemical groups.
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The PSD of a material can be important in understanding its physical and chemical properties. It affects the strength and load-bearing properties of rocks and soils. It affects the reactivity of solids participating in chemical reactions, and needs to be tightly controlled in many industrial products such as the manufacture of printer toner, cosmetics, and pharmaceutical products.
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Cross- reactivity of anti-M protein antibodies with heart muscle has been suggested to be associated in some way with rheumatic fever. It was originally identified by Rebecca Lancefield, who also formulated the Lancefield classification system for streptococcal bacteria. Bacteria like S. pyogenes, which possess M protein are classified in group A of the Lancefield system.
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Calcining temperatures 1000 – 1500 °C produce hard-burned magnesia, which has limited reactivity and calcining at lower temperature, (700–1000 °C) produces light-burned magnesia, a reactive form, also known as caustic calcined magnesia. Although some decomposition of the carbonate to oxide occurs at temperatures below 700 °C, the resulting materials appears to reabsorb carbon dioxide from the air.
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If a Loss-of-coolant accident (LOCA) (e.g. Three Mile Island) or a Reactivity Initiated Accident (RIA) (e.g. Chernobyl or SL-1) occurs then the temperature of this gas can increase. As the fuel pin is sealed the pressure of the gas will increase (PV = nRT) and it is possible to deform and burst the cladding.
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Polygodial is chemical compound found in dorrigo pepper, mountain pepper, horopito, canelo, paracress, water-pepper, and Dendrodoris limbata.Beattie, G.A.C., Spray Oils Beyond 2000, University of Western Queensland, M Jonassohn (1996)Sesquiterpenoid unsaturated dialdehydes - Structural properties that affect reactivity and bioctivity. Doctoral thesis, Lund University, Sweden. . }} Chemically it is a drimane-type sesquiterpene dialdehyde of formula C15H22O2.
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It is debated as to whether top-down executive control regions such as the dorsolateral prefrontal cortex (DLPFC), are required or not to inhibit reactivity of the amygdala activation related to the production of evoked emotional responses. Arguably an initial increase in activation of executive control regions developed during mindfulness training may lessen with increasing mindfulness expertise.
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Structure of the polymeric diethyl ether peroxide The C-O bonds that comprise simple ethers are strong. They are unreactive toward all but the strongest bases. Although generally of low chemical reactivity, they are more reactive than alkanes. Specialized ethers such as epoxides, ketals, and acetals are unrepresentative classes of ethers and are discussed in separate articles.
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In organic chemistry, aluminium hydride is mainly used for the reduction of functional groups. In many ways, the reactivity of aluminium hydride is similar to that of lithium aluminium hydride. Aluminium hydride will reduce aldehydes, ketones, carboxylic acids, anhydrides, acid chlorides, esters, and lactones to their corresponding alcohols. Amides, nitriles, and oximes are reduced to their corresponding amines.
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Robinson et. al. J. Org. Chem. 1992, 57, 7352 This improvement increases the reactivity of the system and allows for formation of fully substituted pyridines whereas use of an α-pyridinium methyl ketone requires that the 3- or 5- position on the resulting pyridine be unsubstituted. Kröhnke condensation of enamino nitrile 20 with enone 21 yielded fused pyridine 22.
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Six nonmetals are categorised as noble gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and the radioactive radon (Rn). In periodic table terms they occupy the outermost right column. They are called noble gases in light of their characteristically very low chemical reactivity. They have very similar properties, all being colorless, odorless, and nonflammable.
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The product of a polymerization is a mixture of polymer molecules of different molecular weights. For theoretical and practical reasons it is of interest to discuss the distribution of molecular weights in a polymerization. The molecular weight distribution (MWD) had been derived by Flory by a statistical approach based on the concept of equal reactivity of functional groups.
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Reactivity meters and removable startup chambers are used for monitoring of reactor startup. Total reactor power is recorded as the sum of the currents of the lateral ionization chambers. The moisture and temperature of the gas circulating in the channels is monitored by the pressure tube integrity monitoring system. The PPDDCS and RCPS are supposed to complement each other.
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The oceanic crust contains the largest aquifer on Earth and supports a vast deep biosphere. Thermal circulation and reactivity of seawater-derived fluids can modify the composition of oceanic plates, lead to the formation of hydrothermal vents that support unique micro- and macro-biological communities and concentrate methane to form massive methane gas and methane hydrate reservoirs.
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As Director of Translational Research in Psychiatry, her major research focus is the identification of mechanisms by which genetic variants and environmental exposure interact to influence stress reactivity and, through these, the risk for affective and anxiety disorders. The ultimate goal of her research is to improve treatment options for patients by better understanding the underlying disease mechanisms.
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Environmental Science and Technology. 23(6): 630-636. In the last few years, research on PRBs has increased because of the reduced water and energy demands and the potential to be more economical than conventional methods. While the reactivity of common PRB materials with chlorinated compounds has long been recognized, in situ applications were not considered until recently.
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2,3-Dihydrothiophene is a heterocyclic compound and an organosulfur compound with the formula SC4H6. It is isomeric with the more symmetrical 2,5-dihydrothiophene. Both isomers of dihydrothiophene are colorless liquids with a thioether-like odor. In terms of their reactivity, both isomers exhibit characteristics of alkenes and thioethers, undergoing addition reactions at carbon and oxidation at sulfur.
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The orientation of dipole moments generated by helices within the active site generates an electropositive region for ideal reactivity with MIO. The partially positive regions in the active site may also help stabilize the charge of a carbanion intermediate. PAL is structurally similar to the mechanistically related histidine ammonia lyase, although PAL has approximately 215 additional residues.
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Carbonyls can be alkylated in nucleophilic addition reactions using organometallic compounds such as organolithium reagents, Grignard reagents, or acetylides. Carbonyls also may be alkylated by enolates as in aldol reactions. Carbonyls are also the prototypical groups with vinylogous reactivity (e.g. the Michael reaction where an unsaturated carbon in conjugation with the carbonyl is alkylated instead of the carbonyl itself).
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Solutions containing ruthenium trichloride are highly active for olefin metathesis. Such catalysts are used commercially for the production of polynorbornene for example. Well defined ruthenium carbene and alkylidene complexes show comparable reactivity and provide mechanistic insights into the industrial processes. The Grubbs' catalysts for example have been employed in the preparation of drugs and advanced materials.
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These particles are of interest in the fields of nanomagnetism, luminescence, electronic transport, and chemical and catalytic reactivity; it has applications in the chemo- and enantioselective labeling of molecules of biological interest and biomolecules as well as, for example, the use of magnetic and catalytic properties on the same object for the storage of renewable energies.
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PWRs also use boric acid to make fine adjustments to reactor power level, or reactivity, using their Chemical and Volume Control System (CVCS). In the case of LOCA, PWRs have three sources of backup cooling water, high pressure injection (HPI), low pressure injection (LPI), and core flood tanks (CFTs). They all use water with a high concentration of boron.
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Organophosphorus compounds are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents. Organophosphorus chemistry is the corresponding science of the properties and reactivity of organophosphorus compounds.
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Potassium hydroxide is an inorganic compound with the formula KOH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), this colorless solid is a prototypical strong base. It has many industrial and niche applications, most of which exploit its caustic nature and its reactivity toward acids. An estimated 700,000 to 800,000 tonnes were produced in 2005.
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Fulminates are chemical compounds which include the fulminate ion. The fulminate ion, , is a pseudohalic ion because its charge and reactivity are similar to those of the halogens. Due to the instability of the ion, fulminate salts are friction-sensitive explosives. The best known is mercury(II) fulminate, which has been used as a primary explosive in detonators.
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The Ariane 1 through Ariane 4 family used a related fuel, a mixture of 75% UDMH and 25% hydrazine hydrate called UH 25. Aerozine is not used as a monopropellant. The extra stability conferred by the methyl groups affects reactivity and thrust. In 1980, a leakage of Aerozine 50 resulted in the 1980 Damascus Titan missile explosion.
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Akin to enamines, enol ethers are electron-rich alkenes by virtue of the electron- donation from the heteroatom via pi-bonding. Enol ethers have oxonium ion character. By virtue of their bonding situation, enol ethers display distinctive reactivity. In comparison with simple alkenes, enol ethers exhibit enhanced susceptibility to attack by electrophiles such as Bronsted acids.
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Dioscorine is one of few alkaloids to possess an isolated isoquinuclide nucleus that is not part of a condensed ring system, unlike catharanthine or other indole alkaloids. Its biosynthesis starts with trigonelline (nicotinic acid methylated at the nitrogen). The pathway was anticipated by the known reactivity of trigonelline. The process yields dumetorine as a side product.
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He was Software Engineer at computer software company Puffin Designs from October 1997 to November 1999 when he became a partner in Reactivity, Inc., a computer software consulting practice. Schroepfer founded the computer software company CenterRun in June 2000, becoming its Chief Architect and Director of Engineering. CenterRun was acquired by Sun Microsystems in November 2003.
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Garcia-Barrera, M. A., Karr, J. E., Trujillo-Orrego, N., Trujillo- Orrego, S., & Pineda, D. A. (2017). Evaluating empathy in Colombian ex- combatants: Examination of the internal structure of the Interpersonal Reactivity Index (IRI) in Spanish. Psychological Assessment, 29(1), 116-122. This version was used to measure empathy in Colombian militants returning to society after having seen combat.
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Additionally, men had memories with significantly more detail than women. Women however, reported significantly higher rates of emotional reactivity. Thus, it is important to conduct further research to fully understand the significant differences between men and women in recall of flashbulb memories. Biological reasons for gender variances in flashbulb memory may be explained by amygdala asymmetry.
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Methyl isocyanide or isocyanomethane is an organic compound and a member of the isocyanide family. This colorless liquid is isomeric to methyl cyanide (acetonitrile), but its reactivity is very different. Methyl isocyanide is mainly used for making 5-membered heterocyclic rings. The C-N distance in methyl isocyanide is very short, 1.158 Å as is characteristic of isocyanides.
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Methyl isocyanide was first prepared by A. Gautier by reaction of silver cyanide with methyl iodide. The common method for preparing methyl isocyanides is the dehydration of N-methylformamide. Many metal cyanides react with methylating agents to give complexes of methyl isocyanide. This kind of reactivity has been invoked as being relevant to the origin of life.
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By the 1990s, the concrete above the arches was suffering from advanced Alkali-Silica Reactivity (ASR) attack. The 1996 rehabilitation project replaced the entire deck system. The decorative architectural elements were replaced either in kind using cast stone or replaced with architectural fiberglass reproductions. The viaduct over the railroad was replaced with adjacent precast/prestressed deck beams made continuous.
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Anticonvulsant/sulfonamide hypersensitivity syndrome is a potentially serious hypersensitivity reaction that can be seen with medications with an aromatic amine chemical structure, such as aromatic anticonvulsants (e.g. diphenylhydantoin, phenobarbital, phenytoin, carbamazepine, lamotrigine), sulfonamides, or other medications with an aromatic amine (e.g., procainamide). Cross-reactivity should not occur between medications with an aromatic amine and medications without an aromatic amine (e.g.
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STM image of a "cyanostar" dendrimer molecule. Molecules have fixed equilibrium geometries—bond lengths and angles— about which they continuously oscillate through vibrational and rotational motions. A pure substance is composed of molecules with the same average geometrical structure. The chemical formula and the structure of a molecule are the two important factors that determine its properties, particularly its reactivity.
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Fluazinam is a broad-spectrum fungicide used in agriculture. It is classed as a diarylamine and more specifically an arylaminopyridine. Its chemical name is 3-chloro-N-(3-chloro-2,6-dinitro-4-trifluoromethylphenyl)-5-trifluoromethyl-2-pyridinamine. The mode of action involves the compound being an extremely potent uncoupler of oxidative phosphorylation in mitochondria and also having high reactivity with thiols.
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Researchers have been able to increase the reactivity of fullerenes by attaching active groups to their surfaces. Buckminsterfullerene does not exhibit "superaromaticity": that is, the electrons in the hexagonal rings do not delocalize over the whole molecule. A spherical fullerene of n carbon atoms has n pi-bonding electrons, free to delocalize. These should try to delocalize over the whole molecule.
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The special materials and processes used in powder metallurgy can pose hazards to life and property. The high surface-area-to-volume ratio of the powders can increase their chemical reactivity in biological exposures (for example, inhalation or ingestion), and increases the risk of dust explosions. Materials considered relatively benign in bulk can pose special toxicological risks when in a finely divided form.
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In contrast, compounds of the type [(η5-C5H5)Fe(CO)2(CH2CH=CHR)] possessing η1-allyl groups are analogous to main group allylmetal species (M = B, Si, Sn, etc.) and react with carbon electrophiles to give allylation products with SE2′ selectivity. Similarly, allenyl(cyclopentadienyliron) dicarbonyl complexes exhibit reactivity analogous to main group allenylmetal species and serve as nucleophilic propargyl synthons.
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Its mechanical properties and non-reactivity in the biological environment allow it to be a suitable material used to cover surfaces in friction in body prostheses (e.g. hip or shoulder prostheses). Defluoridation Defluoridation is the downward adjustment of the level of fluoride in drinking water. Activated Alumina process is one of the widely used adsorption methods for the defluoridation of drinking water.
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Chronic stress and a lack of coping resources available or used by an individual can often lead to the development of psychological issues such as delusions, depression and anxiety (see below for further information).Schlotz W, Yim IS, Zoccola PM, Jansen L, Schulz P (2011). The perceived stress reactivity scale: Measurement invariance, stability, and validity in three countries. Psychol Assess. (pp. 80–94).
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Fukui was awarded the Nobel Prize for his realization that a good approximation for reactivity could be found by looking at the frontier orbitals (HOMO/LUMO). This was based on three main observations of molecular orbital theory as two molecules interact. # The occupied orbitals of different molecules repel each other. # Positive charges of one molecule attract the negative charges of the other.
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Cyclic alkenes are subject to strain resulting from distortion of the sp2-hybridized carbon centers. Illustrative is C60 where the carbon centres are pyramidalized. This distortion enhances the reactivity of this molecule. Angle strain also is the basis of Bredt's rule which dictates that bridgehead carbon centers are not incorporated in alkenes because the resulting alkene would be subject to extreme angle strain.
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The heating programme to be used depends very much on the form and reactivity of the reactants. In the control of either temperature or atmosphere, nature of the reactant chemicals are considered in detail. A good furnace is used for heat treatment. Pelleting of samples is preferred prior to heating, since it increases the area of contact between the grains.
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Indeed, in the fossil of its relative Shuvuuia feather traces were discovered, proving that Alvarezsauridae were among the theropod lineages with feathery or downy integument.Schweitzer, M. H., J. A. Watt, R. Avci, L. Knapp, L. Chiappe, M. Norell & M. Marshall. (1999). "Beta-keratin specific immunological reactivity in feather-like structures of the Cretaceous alvarezsaurid, Shuvuuia deserti." Journal of Experimental Zoology, 285: 146–157.
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Pyridinium chlorochromate (PCC) is a yellow-orange salt with the formula [C5H5NH]+[CrO3Cl]−. It is a reagent in organic synthesis used primarily for oxidation of alcohols to form carbonyls. A variety of related compounds are known with similar reactivity. PCC offers the advantage of the selective oxidation of alcohols to aldehydes or ketones, whereas many other reagents are less selective.
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Use of a difunctional or polyfunctional amine forms a three- dimensional cross-linked network. Aliphatic, cycloaliphatic and aromatic amines are all employed as epoxy hardeners. Amine type hardeners will alter both the processing properties (viscosity, reactivity) and the final properties (mechanical, temperature and heat resistance) of the cured copolymer network. Thus amine structure is normally selected according to the application.
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The first is the stabilization of the transition state as a result of the hydrogen bonding. The second is the electron-withdrawing nature of the oxygen, which draws electron density away from the alkene, lowering its reactivity. 500px Acyclic allylic alcohols exhibit good selectivity as well. In these systems both A1,2 (steric interactions with vinyl) and A1,3 strain are considered.
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The increased reactivity of these and similar dienes is a result of synergistic contributions from donor groups at C1 and C3, raising the HOMO significantly above that of a comparable monosubstituted diene. General form of Danishefsky, Brassard, and Rawal dienes Unstable (and thus highly reactive) dienes, of which perhaps the most synthetically useful are o-quinodimethanes, can be generated in situ.
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Norbornadiene is a bicyclic hydrocarbon and an organic compound. Norbornadiene is of interest as a metal-binding ligand, whose complexes are useful for homogeneous catalysis. It has been intensively studied owing to its high reactivity and distinctive structural property of being a diene that cannot isomerize (isomers would be anti-Bredt olefins). Norbornadiene is also a useful dienophile in Diels-Alder reactions.
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Chronic actinic dermatitis (also known as "Actinic reticuloid," "Chronic photosensitivity dermatitis," "Persistent light reactivity," and "Photosensitive eczema") is a condition where a subject's skin becomes inflamed due to a reaction to sunlight or artificial light. Patients often suffer from other related conditions of the skin that cause dermatitis in response to a variety of stimuli (e.g., flowers, sunscreens, cosmetics, etc.).
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The term carbene ligand is a formalism since many are not derived from carbenes and almost none exhibit the reactivity characteristic of carbenes. Described often as M=CR2, they represent a class of organic ligands intermediate between alkyls (−CR3) and carbynes (≡CR). They feature in some catalytic reactions, especially alkene metathesis, and are of value in the preparation of some fine chemicals.
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Organochlorosilanes allow couplings with aryl chlorides, which are abundant and generally more economical than aryl iodides. A nickel catalyst allows for access to new reactivity of organotrifluorosilanes as reported by GC Fu et al. Secondary alkyl halides are coupled with aryl silanes with good yields using this reaction. The Nickel-catalyzed Hiyama coupling as discovered by GC Fu et al.
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Aluminium is a metal with numerous familiar uses in everyday life. It is most often encountered in construction materials, in electrical devices, especially as the conductor in cables, and in tools and vessels for cooking and preserving food. Aluminium's lack of reactivity with food products makes it particularly useful for canning. Its high affinity for oxygen makes it a powerful reducing agent.
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The molecule first described by Carl Wilhelm Scheele in 1780 and was the first known derivative of the heterocycle known as furan. Since then, the compound's reactivity with different substances and organisms was tested. It was discovered that 2-furoic acid can be the sole source of carbon and energy for the organism Pseudomonas putida. The organism aerobically degrades the compound.
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This allows precise control of consistency and texture while cooking sugar and pectin-thickened preparations. Alone, fruit acid would be sufficient to cause leaching of copper byproducts, but naturally occurring fruit sugars and added preserving sugars buffer copper reactivity. Unlined pans have thereby been used safely in such applications for centuries. Lining copper pots and pans prevents copper from contact with acidic foods.
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Deprotonation can be an important step in a chemical reaction. Acid–base reactions typically occur faster than any other step which may determine the product of a reaction. The conjugate base is more electron- rich than the molecule which can alter the reactivity of the molecule. For example, deprotonation of an alcohol forms the negatively charged alkoxide, which is a much stronger nucleophile.
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Furthermore, nearly all of the distortion energy (92%) arises from the distortion of the 1,3 dipole rather than the cyclooctyne, which has a pre-distorted ground state geometry which increases its reactivity. Fluorination decreases the distortion energy by allowing the transition state to be achieved with a lesser distortion of the 1,3-dipole during reaction, resulting in a larger dipole angle.
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These compounds share many properties with perfluorocarbons such as stability and hydrophobicity, while the functional group augments their reactivity, enabling them to adhere to surfaces or act as surfactants;. Fluorosurfactants, in particular, can lower the surface tension of water more than their hydrocarbon-based analogues. Fluorotelomers, which have some unfluorinated carbon atoms near the functional group, are also regarded as perfluorinated..
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The side-chain of the nucleophilic residue performs covalent catalysis on the substrate. The lone pair of electrons present on the oxygen or sulfur attacks the electropositive carbonyl carbon. The 20 naturally occurring biological amino acids do not contain any sufficiently nucleophilic functional groups for many difficult catalytic reactions. Embedding the nucleophile in a triad increases its reactivity for efficient catalysis.
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He was particularly well known for studies of the reaction of nucleophiles with carbon. He proposed that enzymes use ground state destabilization, termed the Circe Effect, to increase the reactivity of their bound substrates. Many of these research interests were explored in his influential text Catalysis in Chemistry and Enzymology. Jencks published close to 400 scientific papers during his career.
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NFPA 704 standard hazard sticker or placard The US-based National Fire Protection Association (NFPA) has a standard NFPA 704 using a diamond with four colored sections each with a number indicating severity 0–4 (0 for no hazard, 4 indicates a severe hazard). The red section denotes flammability. The blue section denotes health risks. Yellow represents reactivity (tendency to explode).
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Stability at low pressure permits less robust reactor vessels and increases reliability. The high reactivity of fluorine traps most fission reaction byproducts. It appeared that the fluid salt would permit on-site chemical separation of the fuel and wastes. The fuel system was located in sealed cells, laid out for maintenance with long-handled tools through openings in the top shielding.
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Jerome Nickels of Nancy, France: poisoned, died. George Gore of England: fluorine / hydrogen explosion, narrowly escaped injury. Henri Moissan of France: poisoned several times, success, but shortened life. Initial attempts to isolate the element were also hindered by material difficulties: the extreme corrosiveness and reactivity of hydrogen fluoride (and of fluorine gas) as well as problems getting a suitable conducting liquid for electrolysis.
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Figure 9: Potential relationship based on isolobal principles. Uses of the isolobal analogy include providing a shortcut to understanding electronic structure, predicting reactivity and reaction mechanisms, and a method of classifying molecules. Applications are typically utilized to make connections between well-known systems and less familiar systems. For example, the possibility of unsynthesized compounds can be imagined from those of known molecular conformations.
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Chemical vapor deposition is the most common method to produce BN nanosheets because it is a well-established and highly controllable process that yields high-quality material over areas exceeding 10 cm2. There is a wide range of boron and nitride precursors for CVD synthesis, such as borazine, and their selection depends on toxicity, stability, reactivity, and the nature of the CVD method.
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Second generation catalysts have been developed as well. Ruthenium is stable in air and has higher selectivity and lower reactivity than molybdenum, the most promising of the previously discovered catalysts. In addition, Grubbs took a green chemistry approach to catalysis that reduced the potential to create hazardous waste. Grubbs catalyst has become a standard for general metathesis applications in ordinary laboratories.
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Their electronic structures can be interrogated by techniques such as photoelectron spectroscopy, while infrared multiphoton dissociation spectroscopy is more probing the clusters geometry. Their properties (Reactivity, Ionization potential, HOMO-LUMO-gap) often show a pronounced size dependence. Examples of such clusters are certain aluminium clusters as superatoms and certain gold clusters. Certain metal clusters are considered to exhibit metal aromaticity.
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An obstacle for the use of quantum dots in photocatalysis is the presence of surfactants on the surface of the dots. These surfactants (or ligands) interfere with the chemical reactivity of the dots by slowing down mass transfer and electron transfer processes. Also, quantum dots made of metal chalcogenides are chemically unstable under oxidizing conditions and undergo photo corrosion reactions.
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DDT and its breakdown product DDE disturb estrogenic activity and possibly lead to breast cancer. Fetal DDT exposure reduces male penis size in animals and can produce undescended testicles. Pesticide can affect fetuses in early stages of development, in utero and even if a parent was exposed before conception. Reproductive disruption has the potential to occur by chemical reactivity and through structural changes.
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He was also a member of the Advisory Panel on General Science at the Department of Defense from 1959 to 1963. TRIGA is the world's most popular research reactor Under his leadership, General Atomics developed TRIGA, a small reactor for universities and laboratories. TRIGA used uranium zirconium hydride (UZrH) fuel, which has a large, prompt negative fuel temperature coefficient of reactivity.
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Caesium hydroxide or cesium hydroxide (CsOH) is a chemical compound consisting of caesium ions and hydroxide ions. It is a strong base (pKb=-1.76), much like the other alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. In fact, caesium hydroxide is corrosive enough to dissolve through glass quickly . Due to its high reactivity, Caesium Hydroxide is extremely hygroscopic.
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Suggested theories include tumor production of plakin proteins which initiate an autoimmune response against them, and cross- reactivity of tumor antigens and epidermal antigens. Once the molecules that hold the various levels of the membranes together are attacked, they are unable to function properly, and the tissue breaks apart. This is manifested as the associated blistering and lesions of PNP.
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903-965 the study of original quinonoid zwitterions with delocalized organic π systems, which promote electronic communication between metal centres,P. Braunstein, O. Siri, J.-P. Taquet, M.-M. Rohmer, M. Bénard, R. Welter « A 6π + 6π potentially antiaromatic zwitterion preferred to a quinoidal structure: Its reactivity towards organic and Inorganic reagents. », J. Am. Chem. Soc., 2003, 125, p. 12246-12256O.
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One structurally distinct penem is BRL 42715. This molecule has no substitution at the above position, but has a bulky group attached to the β-lactam ring, and it displays effective inhibition of class C β-lactamases, but no antimicrobial activity. One possible consequence of these structural differences of penems from other β-lactams may be reduced immunogenicity and immunogenic cross-reactivity.
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The fuel was of highly enriched uranium (90% ) in the form of UC2 (uranium carbide). A beryllium reflector was used on the ends of the reactor, and electricity was generated using silicon-germanium semiconductors. The Romashka reactor didn't use liquid coolant; it was designed to be simple, compact, and light. Temperature was self-regulated through the use of a negative temperature reactivity coefficient.
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Direct immunofluorescence, although somewhat less common, has notable advantages over the secondary (indirect) procedure. The direct attachment of the messenger to the antibody reduces the number of steps in the procedure, saving time and reducing non-specific background signal. This also limits the possibility of antibody cross-reactivity and possible mistakes throughout the process. However, some disadvantages do exist in this method.
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TREAT Control Rod Drive Mechanisms TREAT has three banks of control rod drive mechanisms, the control/shutdown rods, the compensation/shutdown rods, and the transient rods. There are 4 drive mechanisms in each group. The drive mechanisms are below the reactor, and raise the control rods out of the reactor to increase reactivity. These banks of control rods are arranged in two rings.
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The study of how substituents affect the reactivity of a molecule or the rate of reactions is of significant interest to chemists. Substituents can exert an effect through both steric and electronic interactions, the latter of which include resonance and inductive effects. The polarizability of molecule can also be affected. Most substituent effects are analyzed through linear free energy relationships (LFERs).
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An electronic effect influences the structure, reactivity, or properties of molecule but is neither a traditional bond nor a steric effect.G. L. Miessler and D. A. Tarr “Inorganic Chemistry” 3rd Ed, Pearson/Prentice Hall publisher, . In organic chemistry, the term stereoelectronic effect is also used to emphasize the relation between the electronic structure and the geometry (stereochemistry) of a molecule.
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The reactivity of hydroquinone's O-H groups resembles that of other phenols, being weakly acidic. The resulting conjugate base undergoes easy O-alkylation to give mono- and diethers. Similarly, hydroquinone is highly susceptible to ring substitution by Friedel-Crafts reactions such as alkylation. This reaction is exploited en route to popular antioxidants such as 2-tert- butyl-4-methoxyphenol ("BHA").
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A dicarboxylic acid is an organic compound containing two carboxyl functional groups (−COOH). The general molecular formula for dicarboxylic acids can be written as HO2C−R−CO2H, where R can be aliphatic or aromatic. In general, dicarboxylic acids show similar chemical behavior and reactivity to monocarboxylic acids. Dicarboxylic acids are also used in the preparation of copolymers such as polyamides and polyesters.
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Unlike the case for carbonyls without a flanking alkene group, α,β-unsaturated carbonyl compounds are susceptible to attack by nucleophiles at the β carbon. This pattern of reactivity is called vinylogous. Examples of unsaturated carbonyls are acrolein (propenal), mesityl oxide, acrylic acid, and maleic acid. Unsaturated carbonyls can be prepared in the laboratory in an aldol reaction and in the Perkin reaction.
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A typical classification system for most commonly used sealants is shown below. Classification of sealants by reactivity and chemistry Types of sealants fall between the higher-strength, adhesive-derived sealers and coatings at one end, and extremely low-strength putties, waxes, and caulks at the other. Putties and caulks serve only one function – i.e., to take up space and fill voids.
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Chronic stress and a lack of coping resources available or used by an individual can often lead to the development of psychological issues such as depression and anxiety (see below for further information).Schlotz W, Yim IS, Zoccola PM, Jansen L, Schulz P (2011). The perceived stress reactivity scale: Measurement invariance, stability, and validity in three countries. Psychol Assess. (pp. 80–94).
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Neurocritical Care. 2015.Stutzman S, Olson D, Saju C, Wilson M, Aiyagari V. Interrater reliability of pupillar assessments among physicians and nurses. UT Southwestern Medical Center; 2014. Automated pupillometry involves the use of a pupillometer, a portable, handheld infrared device that provides a reliable and objective measurement of pupillary size, symmetry, and reactivity through measurement of the pupil light reflex.
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This can also be seen when comparing the halogens. Bromine, iodine, and chlorine all have similar A-values even though their atomic radii differ. A-values then, predict the apparent size of a substituent, and the relative apparent sizes determine the differences in steric effects between compounds. Thus, A-values are useful tools in determining compound reactivity in chemical reactions.
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J. Org. Chem. 2016, 81(11), 4464-4474. DOI: 10.1021/acs.joc.6b00144. The group reports a method by which the benzylation reaction, empirically low yielding and with significant formation of byproducts due to the generally low reactivity of the target 1’-hydroxyl group in sucrose, was carried out to up to 95% yields with excellent selectivity for the synthetic molecule.
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It is a key component of hemoglobin, important to nitrogen fixation as part of the Nitrogenase enzyme family, and as part of the iron-sulfur core of ferredoxin it facilitates electron transport in chloroplasts, eukaryotic mitochondria, and bacteria. Due to the high reactivity of Fe2+ with oxygen and low solubility of Fe3+, iron is a limiting nutrient in most regions of the world.
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The mode of burning of the clinker is also important. Clinker rapidly burned at the minimum temperature for combination, then rapidly cooled, contains small, defective crystals that grind easily. These crystals are usually also optimal for reactivity. On the other hand, long burning at excess temperature, and slow cooling, lead to large, well-formed crystals that are hard to grind and un- reactive.
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Poisonous compounds may be useful either for their toxicity, or, more often, because of another chemical property, such as specific chemical reactivity. Poisons are widely used in industry and agriculture, as chemical reagents, solvents or complexing reagents, e.g. carbon monoxide, methanol and sodium cyanide, respectively. They are less common in household use, with occasional exceptions such as ammonia and methanol.
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For instance, phosgene is a highly reactive nucleophile acceptor, which makes it an excellent reagent for polymerizing diols and diamines to produce polycarbonate and polyurethane plastics. For this use, millions of tons are produced annually. However, the same reactivity makes it also highly reactive towards proteins in human tissue and thus highly toxic. In fact, phosgene has been used as a chemical weapon.
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A capping agent is used during nanoparticle synthesis to inhibit particle growth and aggregation. The chemical blocks or reduces reactivity at the periphery of the particle—a good capping agent has a high affinity for the new nuclei. Citrate ions or tannic acid function both as a reducing agent and a capping agent. Less sodium citrate results in larger particles.
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As the limit values for many impurities are very low this sets stringent demands on the sensitivity of the analytical methods. Moreover, the high reactivity of some impurities requires use of a properly passivated sampling and analytical systems. A combination of different instruments (e.g. gas chromatography, infrared spectroscopy and mass spectroscopy) is now needed to cover all components listed in ISO 14687-2.
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Bioglass has to be stored in a dry environment, as it readily absorbs moisture and reacts with it. Bioglass 45S5 is manufactured by conventional glass-making technology, using platinum or platinum alloy crucibles to avoid contamination. Contaminants would interfere with the chemical reactivity in organism. Annealing is a crucial step in forming bulk parts, due to high thermal expansion of the material.
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In response to this the clinical use of flunoxaprofen has also stopped, even though studies have shown that flunoxaprofen is less toxic than benoxaprofen. The toxicity of these nonsteroidal anti-inflammatory drugs may be related to the covalent modification of proteins in response to the drugs' reactive acyl glucuronides. The reactivity of the acyl glucuronides can affect the protein binding.
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Hershey said the reactor is a > "bragging point" for Reed. "It's just a neat facility," he said. The "zero-risk facility" comment reflects the reactor design which is a pin- type Low Enriched Uranium natural circulation driven LWR, with a very strong negative temperature coefficient. As such, it is impossible to overheat the reactor, even in the case of a sudden reactivity insertion.
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For many decades the enzyme was thought to catalyze the following reaction: :NH2OH + H2O -> NO2^- + 5 H+ + 4e^- Recent work in the field, however, reveals that this enzyme catalyzes an entirely different reaction: :NH2OH -> NO + 3H+ + 3e^- Subsequent oxidation of the nitric oxide to nitrite caused by reaction with oxygen accounts for the reactivity previous described by Hooper et al.
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TMS functionalized polyolefin via Ti complex catalysis Catalytic polymerization appears to have the most control compared to other polymerization methods for randomly functionalized polyolefins. Catalytic routes predominantly undergo a coordination/migratory insertion pathway. The functionality of the olefin highly affects the reactivity of the olefin, and hence its relative rate of coordination. Examples of early transition metal catalysts includes titanium and zirconium complexes.
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Magnetic nanoparticles are of potential use as a catalyst or catalyst supports. In chemistry, a catalyst support is the material, usually a solid with a high surface area, to which a catalyst is affixed. The reactivity of heterogeneous catalysts occurs at the surface atoms. Consequently, great effort is made to maximize the surface area of a catalyst by distributing it over the support.
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Azeotropic point and corresponding composition drift associated with this unstable critical point. Binary copolymerization resembles distillation of a bicomponent liquid mixture with reactivity ratios corresponding to the ratio of vapor pressures of the pure components in the latter case. Distillation terminology is also borrowed for the case of azeotropic compositions in copolymer systems. Azeotropic points occur where F_1 is equal to f_1.
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Nonetheless, initial positive results are not taken seriously, because false positives can result from chemical cross-reactivity, second-hand contact such as a handshake with someone who has handled a drug, or lingering environmental contamination. The threshold for action may involve third or fourth positive test results or positive tests following prior negative tests, as well as the quantity of drug detected.
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Unlike the related 5-membered heterocycles pyrrole, thiophene, and furan, the aromaticity of phospholes is diminished, reflecting the reluctance of phosphorus to delocalize its lone pair. The main indication of this difference is the pyramidalization of phosphorus. The absence of aromaticity is also indicated by the reactivity of phospholes. Phospholes undergo different cycloaddition reactions, coordination properties of phospholes are also well studied..
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Many alternative reagents have been developed to complement the use of phthalimides. Most such reagents (e.g. the sodium salt of saccharin and di- tert-butyl-iminodicarboxylate) are electronically similar to the phthalimide salts, consisting of imido nucleophiles. In terms of their advantages, these reagents hydrolyze more readily, extend the reactivity to secondary alkyl halides, and allow the production of secondary amines.
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Flash compositions used in firecrackers usually consist of a mixture of aluminium powder and potassium perchlorate. This mixture, sometimes called flash powder, is also used in ground and air fireworks. As an oxidizer, potassium perchlorate can be used safely in the presence of sulfur, whereas potassium chlorate cannot. The greater reactivity of chlorate is typical – perchlorates are kinetically poorer oxidants.
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Perfluorinated oxaziridines are known to hydroxylate unactivated hydrocarbons with remarkable regio- and diastereospecificity. This is a highly coveted transformation, and similar reactivity and specificity is seldom rivaled, especially considering the nonmetallic nature of the oxidant. Perfluorinated oxaziridines show high selectivity toward tertiary hydrogens. Hydroxylation of primary carbons and dihydroxylation of a compound with two oxidizable sites have never been observed.
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2, 519 (1992), . as a transesterification reagent (but showing less reactivity than trimethoxymethane) and as a reagent for the synthesis of 2-aminobenzoxazoles, which are used as molecular building blocks in pharmaceutical active ingredients used in neuroleptics, sedatives, antiemetics, muscle relaxants, fungicides and others.C. L. Cioffi et al., Synthesis of 2-Aminobenzoxazoles Using Tetramethyl Orthocarbonate or 1,1-Dichloro-diphenoxymethane, J. Org. Chem.
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Operando spectroscopy is an analytical methodology wherein the spectroscopic characterization of materials undergoing reaction is coupled simultaneously with measurement of catalytic activity and selectivity. The primary concern of this methodology is to establish structure-reactivity/selectivity relationships of catalysts and thereby yield information about mechanisms. Other uses include those in engineering improvements to existing catalytic materials and processes and in developing new ones.
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TiH1.95 is unaffected by water and air. It is slowly attacked by strong acids and is degraded by hydrofluoric and hot sulfuric acids. It reacts rapidly with oxidising agents, this reactivity leading to the use of titanium hydride in pyrotechnics. The material has been used to produce highly pure hydrogen, which is released upon heating the solid starting at 300 °C.
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Compounds with carbon phosphorus(III) multiple bonds are called phosphaalkenes (R2C=PR) and phosphaalkynes (RC≡P). They are similar in structure, but not in reactivity, to imines (R2C=NR) and nitriles (RC≡N), respectively. In the compound phosphorine, one carbon atom in benzene is replaced by phosphorus. Species of this type are relatively rare but for that reason are of interest to researchers.
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Such compounds are prepared by reduction of bulky arylgermanium(II) halides.Philip P. Power "Bonding and Reactivity of Heavier Group 14 Element Alkyne Analogues" Organometallics 2007, volume 26, pp 4362–4372. As with silicon and contrasting with carbon, compounds containing Ge=C (germenes) and Ge=Ge (digermylenes) double bonds are rare. One example is the bulky derivatives of germabenzene, an analogue of benzene.
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For many applications, organobromides represent a compromise of reactivity and cost. Organobromides are typically produced by additive or substitutive bromination of other organic precursors. Bromine itself can be used, but due to its toxicity and volatility safer brominating reagents are normally used, such as N-bromosuccinimide. The principal reactions for organobromides include dehydrobromination, Grignard reactions, reductive coupling, and nucleophilic substitution.
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There are 38 E2 enzymes in humans. They all contain a conserved catalytic core domain that interacts with E1 and E3 and many E2s possess additional N- and/or C-terminal protein sequences. In contrast to other E2s, residues necessary for lysine reactivity are absent: the D87 and D117 residues (in UBCH5C numbering) are replaced by Pro and His residues.
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Titanium is one of the few elements that burns in pure nitrogen gas, reacting at to form titanium nitride, which causes embrittlement. Because of its high reactivity with oxygen, nitrogen, and some other gases, titanium filaments are applied in titanium sublimation pumps as scavengers for these gases. Such pumps inexpensively and reliably produce extremely low pressures in ultra-high vacuum systems.
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The reactor uses 0.7% enriched uranium with Zircaloy-4 cladding as fuel. The core produces 2166 MW of heat which is converted into 700 MW of electricity at an efficiency of 32%. Because of lack of excess reactivity inside the reactor, it needs to be refuelled continuously during operation. The reactor is designed for an estimated life of 40 years.
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The sudden increase in temperature can also lead to violent boiling of the extremely acidic solution. Solutions made using hydrogen peroxide at concentrations greater than 50% may cause an explosion. Once the mixture has stabilized, it can be further heated to sustain its reactivity. The hot (often bubbling) solution cleans organic compounds off substrates and oxidizes or hydroxylates most metal surfaces.
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Data were extracted independently by two raters. All analyses were conducted on intent- to-treat data. Results revealed that ABM produces a small but significant reduction in SAD symptoms (g = 0.27), reactivity to speech challenge (g = 0.46), and AB (g = 0.30). These effects were moderated by characteristics of the ABM procedure, the design of the study, and trait anxiety at baseline.
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Ball mills are used for grinding materials such as coal, pigments, and feldspar for pottery. Grinding can be carried out wet or dry, but the former is performed at low speed. Blending of explosives is an example of an application for rubber balls. For systems with multiple components, ball milling has been shown to be effective in increasing solid-state chemical reactivity.
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References range may vary with age, sex, race, pregnancy, diet, use of prescribed or herbal drugs and stress. Reference ranges often depend on the analytical method used, for reasons such as inaccuracy, lack of standardisation, lack of certified reference material and differing antibody reactivity. Also, reference ranges may be inaccurate when the reference groups used to establish the ranges are small.
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In the Simmons–Smith reaction the reactive carbenoid is iodomethylzinc iodide, which is typically formed by a reaction between diiodomethane and a zinc- copper couple. Modifications involving cheaper alternatives have been developed, such as dibromomethane or diazomethane and zinc iodide. The reactivity of the system can also be increased by exchanging the zinc‑copper couple for diethylzinc. Asymmetric versions are known.
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1-Octene is an organic compound with a formula CH2CHC6H13. The alkene is classified as a higher olefin and alpha-olefin, meaning that the double bond is located at the alpha (primary) position, endowing this compound with higher reactivity and thus useful chemical properties. 1-Octene is one of the important linear alpha olefins in industry. It is a colourless liquid.
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Skin allergy to cefaclor The principal side effect of the cephalosporins is hypersensitivity. Penicillin-sensitive patients will also be allergic to the cephalosporins, depending on the cephalosporin generation. The previous percentage of 10% cross reactivity rates are often overestimated. Allergic reactions may present as, for example, rashes, pruritus (itching), urticaria, serum sickness-like reactions with rashes, fever and arthralgia, and anaphylaxis.
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There has been no observed cleavages or twinning. Space group has been determined as [Pbam] and cell dimensions were calculated to a = 9.213(6) b = 12.229(7) c = 3.001(2) Z = 4. Bonaccordite is insoluble and has only shown reactivity to hydrochloric acid. It is very hard to clean it off of fuel rods in nuclear power reactors where it is sometimes formed.
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Measuring empathic tendencies: Reliability and validity of the Dutch version of the Interpersonal Reactivity Index. Psychologica Belgica, 47(4), 235-260. The researchers found that their translation is just as valid and reliable as Davis's original version, albeit in their educated, still Westernized sample. Another study by Péloquin and Lafontaine (2010) adapted the IRI to specifically measure empathy in couples rather than individuals.
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The yield is good, but commercially significant side products are generated by virtue of reactivity of partially hydrogenated intermediates. These other products include 1,2-Cyclohexanediamine, hexamethyleneimine, and the triamine bis(hexamethylenetriamine). An alternative process uses Raney nickel as the catalyst and adiponitrile that is diluted with hexamethylenediamine itself (as the solvent). This process operates without ammonia and at lower pressure and temperature.
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It is chemically distinct from heparin, has different protein-binding properties because of its low degree of sulphation and low surface charge density and thus has little cross-reactivity in heparin-intolerant patients. The TGI activity, considered by Fernandes et al. [Thromb Haemostas 1987;58/3:286-93 to provide an index of antithrombotic potential, of danaparoid has a half-life of 6.7 hours.
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The 24-hour diet recall is affected by reactivity. The 24-hour diet recall is a poor method for measuring intake for food or drink with a high day-to-day variability. The 24-hour diet recall is unsuitable for large scale studies due to its time, literacy, and economic constraints. 24-hour diet recalls are used less frequently in pregnant women.
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The "Multitest Mérieux" or "CMI Multitest" system (Multitest IMC, Istituto Merieux Italia, Rome, Italy) has been used as a general test of the level of cellular immunity. It is an intradermal test of skin reactivity (similar to tuberculin tests) in which a control (glycerol) is used with seven antigens of bacterial or fungal origin (tetanus toxoid, tuberculin, diphtheria, streptococcus, candida, trichophyton, and proteus). In this test reactions are categorized according to the number of antigens provoking a response and the summed extent of the skin response to all seven antigens. Here anergy is defined as a region of skin reactivity of 0–1 mm, hypoergy as a reaction of 2–9 mm in response to fewer than three antigens, normergic as a reaction of 10–39 mm or to three or more antigens, and hyperergy for a reaction of 40 mm or more.
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From these observations, frontier molecular orbital (FMO) theory simplifies prediction of reactivity to analysis of the interaction between the more energetically matched HOMO-LUMO pairing of the two reactants. In addition to providing a unified explanation of diverse aspects of chemical reactivity and selectivity, it agrees with the predictions of the Woodward–Hoffmann orbital symmetry and Dewar-Zimmerman aromatic transition state treatments of thermal pericyclic reactions, which are summarized in the following selection rule: > "A ground-state pericyclic change is symmetry-allowed when the total number > of (4q+2)s and (4r)a components is odd" (4q+2)s refers to the number of aromatic, suprafacial electron systems; likewise, (4r)a refers to antiaromatic, antarafacial systems. It can be shown that if the total number of these systems is odd then the reaction is thermally allowed.
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James R. Durig, Stephen Bell, Gamil A. Guirgis (1996): "Infrared and Raman spectra, conformational stability, ab initio calculations and vibrational assignment for 1,2-pentadiene (ethyl allene)". Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, volume 52, issue 14, pages 1843-1859. S. Boue and Rangaswamy Srinivasan (1970): "Differences in reactivity between excited states of cis- and trans-1,3-pentadiene". Journal of the American Chemical Association, volume 92, issue 10, pages 3226–3227. Juergen Herzler , Jeffrey A. Manion, and Wing Tsang (2001): "1,2‐Pentadiene decomposition". International Journal of Chemical Kinetics, volume 33, issue 11, pages 755-767. Aldo Priola, Sebastiano Cesca, Giuseppe Ferraris, and Mario Bruzzone (1975): "Relative reactivity of cis‐ and trans‐1,3‐pentadiene in the cationic copolymerization with isobutene". Die Makromolekulare Chemie, volume 176, issue 7, pages 1969-1981. Paul N. Kogerman (1930): "Synthesis of 1,4-pentadiene".
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An association between vasectomy and primary progressive aphasia, a rare variety of frontotemporal dementia, was reported. However, it is doubtful that there is a causal relationship. The putative mechanism is a cross-reactivity between brain and sperm, including the shared presence of neural surface antigens. In addition, the cytoskeletal tau protein has been found only to exist outside of the CNS in the manchette of sperm.
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Nickel and Molybdenum are typically also found in stainless steels. Other significant metallic alloys are those of aluminium, titanium, copper and magnesium. Copper alloys have been known for a long time (since the Bronze Age), while the alloys of the other three metals have been relatively recently developed. Due to the chemical reactivity of these metals, the electrolytic extraction processes required were only developed relatively recently.
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For example, it oxidatively adds H2 to give a dihydride. He subsequently discovered that his complex reversibly bound O2, which was then a startling achievement. He discovered the main reactions of oxidative addition, a process that is central to homogeneous catalysis in organometallic chemistry. He demonstrated a number of important substituent effects on the oxidative addition, such as the greater reactivity of Ir(I) vs.
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In general, acidity of donor sites correlates well with the strength of the donor. For example, it is a common strategy to add electron-withdrawing aryl substituents on a thiourea catalyst, which can increase its acidity and thus the strength of its hydrogen bonding. However, it is still unclear how donor strength correlates with desired reactivity. Importantly, more acidic catalysts are not necessarily more effective.
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These two glycoproteins are the targets of numerous serologic reactions and tests including neutralization and hemagglutination inhibition. The alphaviruses show various degrees of antigenic cross-reactivity in these reactions and this forms the basis for the seven antigenic complexes, 30 species and many subtypes and varieties. The E2 protein is the site of most neutralizing epitopes, while the E1 protein contains more conserved, cross-reactive epitopes.
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At the laboratory of atomic and molecular physics, Duchesne studied the dynamic behaviour of molecules and identified the role of molecular vibrations in chemical reactivity. In 1950 this gave rise to the theory of infra-red photoactivation. Duchesne studied the properties of the solid state. He was the first to establish the law governing the broadening of quadripolar nuclear resonance in crystals containing isomorphic impurities.
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The reflector scattered back into the core some of the neutrons that escaped from the core. The reactor pool was surrounded by a concrete biological shield, which acted as a radiation protection in the horizontal direction. The reactor had four control rods made of boron carbide. A feature of the fuel material, uranium zirconium hydride, is a strong negative feedback between the temperature and the reactivity.
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The basis of the test is the presence of antigenic cross-reactivity between Rickettsia spp. and certain serotypes of non-motile Proteus spp., a phenomenon first published by Edmund Weil and Arthur Felix in 1916.Cruikshank, R. The Weil-Felix reaction in typhus fever. 1927. J Hyg (Lond) 27(1): 64–69. Weil-Felix is a nonspecific agglutination test which detects anti-rickettsial antibodies in patient’s serum.
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The protein family of annexins has continued to grow since their association with intracellular membranes was first reported in 1977. The recognition that these proteins were members of a broad family first came from protein sequence comparisons and their cross-reactivity with antibodies. One of these workers (Geisow) coined the name Annexin shortly after. As of 2002 160 annexin proteins have been identified in 65 different species.
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The production of the metals itself is difficult due to their reactivity. The formation of oxides, nitrides and carbides must be avoided to yield workable metals; this is normally achieved by the Kroll process. The oxides (MO2) are reacted with coal and chlorine to form the chlorides (MCl4). The chlorides of the metals are then reacted with magnesium, yielding magnesium chloride and the metals.
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Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond.Synthesis of Organometallic Compounds: A Practical Guide Sanshiro Komiya Ed. 1997C. Elschenbroich, A. Salzer Organometallics : A Concise Introduction (2nd Ed) (1992) from Wiley-VCH: Weinheim. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.
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H2@C60 is found to be a stable molecule. it survives 10 minutes at 500 °C and shows the same chemical reactivity as empty C60. The electronic properties are also largely unaffected. The process of hydrogen introduction and release can be facilitated by increasing the size of the orifice. This can be done by replacing sulfur by selenium (sodium thiolate, Se8) exploiting larger C-Se bond length.
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What distinguishes MICs from traditional thermites is that the oxidizer and a reducing agent, normally iron oxide and aluminium, are in the form of extremely fine powders (nanoparticles). This dramatically increases the reactivity relative to micrometre-sized powder thermite. As the mass transport mechanisms that slow down the burning rates of traditional thermites are not so important at these scales, the reaction proceeds much more quickly.
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Polyfunctional primary amines form an important class of epoxy hardeners. Primary amines undergo an addition reaction with the epoxide group to form a hydroxyl group and a secondary amine. The secondary amine can further react with an epoxide to form a tertiary amine and an additional hydroxyl group. Kinetic studies have shown the reactivity of the primary amine to be approximately double that of the secondary amine.
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A related class is cycloaliphatic epoxy resin, which contains one or more cycloaliphatic rings in the molecule (e.g. 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate). This class also displays lower viscosity at room temperature, but offers significantly higher temperature resistance than the aliphatic epoxy diluents. However, reactivity is rather low compared to other classes of epoxy resin, and high temperature curing using suitable accelerators is normally required.
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It is widely used in the design of new drugs and materials. Examples of such properties are structure (i.e., the expected positions of the constituent atoms), absolute and relative (interaction) energies, electronic charge density distributions, dipoles and higher multipole moments, vibrational frequencies, reactivity, or other spectroscopic quantities, and cross sections for collision with other particles. The methods used cover both static and dynamic situations.
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Further concerns are related to the fact that ESM may substantively change the phenomenon being studied. Reactivity or priming effects may occur, such that repeated measurement may cause changes in the participants' experiences. This method of sampling data is also highly vulnerable to common method variance. Further, it is important to think about whether or not an appropriate dependent variable is being used in an ESM design.
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Na4[B3(NCy2)3]2 • 2 DME acts as a strong reductant on a variety of substances. The reactivity of triboracyclopropenyl- containing compounds is relatively under-explored, as only one example has been prepared in the solution phase. The compound reported by Braunschweig, Na4[B3(NCy2)3]2 • 2 DME, is an extremely potent reductant with an oxidation potential of -2.42 V vs. the ferrocene/ferrocenium couple.
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The potent Lewis acidity of 12 revealed a novel reaction pathway whereby the alkyne first adds to the borole nucleophilically, followed by subsequent aryl migration and ring expansion to afford the boracyclohexadiene 7 as the predominant species (75%). Both reaction pathways likely compete with each other and as a result, the nature of the alkyne (nucleophilicity, substitution pattern) strongly dictates which reactivity is favored.
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Both free and immobilized radicals display very different chemical characteristics from atoms and molecules containing only complete bonds. Generally, they are extremely reactive. Immobilized free radicals, like their mobile counterparts, are highly unstable, but they gain some kinetic stability because of limited mobility and steric hindrance. While free radicals are usually short lived, immobilized free radicals often exhibit a longer lifetime because of this reduction in reactivity.
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Out of many derivatives, DBP-DIOP exhibits good regio- and enantioselectivity in the hydroformylation of butenes and styrene. DIOP was the first chiral ligand used in the platinum-tin-catalyzed hydroformylation. The reactivity, chemo – and the enantioselectivity of DIOP is influenced by CO and H2 pressure and polarity of the solvents. The best results in asymmetric hydroformylation are achieved in solvents with medium polarity: benzene and toluene.
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Xenon hexafluoroplatinate is the product of the reaction of platinum hexafluoride and xenon, in an experiment that proved the chemical reactivity of the noble gases. This experiment was performed by Neil Bartlett at the University of British Columbia, who formulated the product as "Xe+[PtF6]−", although subsequent work suggests that Bartlett's product was probably a salt mixture and did not in fact contain this specific salt.
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Halothene-reactive castrated males, as opposed to un-modified boars, differed from non-reactive in "all carcass and meat quality traits", and had "significantly lower feed conversion ratios". Halothene reactivity seems to be more heritable from the sire than the dam; in a population with an average 24.9% of individuals being reactive, 40.7% of those with reacting sires were themselves reactive, vs. 21.3% without.
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Confounds are threats to internal validity. Confounds refer to variables that should have been held constant within a specific study but that were accidentally allowed to vary (and covary with the independent/predictor variable). A confound exists when the treatment influences the outcome, but not for the theoretical reason proposed by the researchers. Confounds may be related to the "reactivity" of the study (e.g.
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Myasthenia gravis is another common autoimmune disease. This disease causes fluctuating muscle weakness and fatigue. The disease occurs due to detectable antibodies produced against the human acetylcholine receptor. The receptor contains a seven amino acid sequence (Trp-Thr-Tyr-Asp-Gly-Thr-Lys) in the α-subunit that demonstrates immunological cross-reactivity with a shared immunodominant domain of gpD of the herpes simplex virus (HSV).
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The cause is typically the eating of fish or foods that contain fish. Once an allergic reaction has occurred it usually remains a lifelong sensitivity. Briefly, the immune system overreacts to proteins found in fish. The allergic reaction to shellfish and crustaceans such as lobster and shrimp is to a different protein - tropomyosin - so there is no cross-reactivity between fish and shellfish allergy.
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Using the isopeptidase domain, USP18 specifically deconjugates ISG15 (interferon- stimulated gene 15) from tagged proteins. This reaction is termed deISGylation, as the initial conjugation of ISG15 to newly-synthesized proteins is termed ISGylation, a process akin to ubiquitination. However, unlike other de-ubiquitinating enzymes, USP18 is specific to ISG15, and exhibits no cross-reactivity with ubiquitin. The consequences of ISGylation and deISGylation are incompletely understood.
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Recent approaches use high-throughput sequencing to achieve the same purpose with greater throughput and sensitivity. The reactivity profile can be used to study the degree of structure at particular positions for specific hypotheses, or used in conjunction with computational algorithms to produce a complete experimentally supported structure model. Depending on the chemical reagent used, some reagents, e.g. hydroxyl radicals, would cleave the RNA molecule instead.
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In the case of asymmetric induction, we are considering the effects of one asymmetric centre on a molecule on the reactivity of other functional groups on that molecule. The closer together these two sites are, the larger an influence is expected to be observed. A more holistic approach to evaluating these factors is by computational modelling,Houk, K. N. et al., Science, 1986, 231, 1108-1117.
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Most reactions take advantage of the high reactivity of the C–Cl bond. In its largest-scale application, chloroacetic acid is used to prepare the thickening agent carboxymethyl cellulose and carboxymethyl starch. Chloroacetic acid is also used in the production of phenoxy herbicides by etherification with chlorophenols. In this way 2-methyl-4-chlorophenoxyacetic acid (MCPA), 2,4-Dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) are produced.
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N-fluoropyridinium ions and iminium ions can also be used as electrophilic fluorinating reagents. The counteranions of these salts, although they are not directly involved in the transfer of fluorine to the substrate, influence reactivity in subtle ways and may be adjusted using a variety of methods.Umemoto, T.; Harasawa, K.; Tomizawa, G.; Kawada, K.; Tomita, K. Bull. Chem. Soc. Jpn. 1991, 64, 1081. :File:EFScope2.
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The reactivity and uses of TEPA are similar to those for the related ethylene amines ethylenediamine and diethylenetriamine and triethylenetetramine. It is primarily used as a curing agent or hardener in epoxy chemistry. This can be on its own or reacted with tall oil fatty acid (TOFA) and its dimer to make an amidoamine. This amidoamine is then used as the curing agent for epoxy resin systems.
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Reactive & Functional Polymers is a monthly peer-reviewed scientific journal, established in 1982 and published by Elsevier. It covers research on both the science and the technology of reactive polymers (those with functional groups) including polymers and other polymers with specific chemical reactivity or other functionality. The journal publishes both original research and review papers. The editor-in-chief is Alexander Bismarck (University of Vienna).
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Trimethylenemethane is a neutral, four-carbon molecule composed of four pi bonds; thus, it must be expressed either as a non-Kekulé molecule or a zwitterion. The orbital energy levels of TMM reveal that it possesses singlet and triplet states; generally, these states exhibit different reactivity and selectivity profiles.Baseman, R. J.; Pratt, D. W.; Chow, M.; Dowd, P. J. Am. Chem. Soc. 1976, 98, 5726.
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Different thioredoxin fold-containing proteins vary greatly in their reactivity and in the pKa of their free thiols, which derives from the ability of the overall protein structure to stabilize the activated thiolate. Although the structure is fairly consistent among proteins containing the thioredoxin fold, the pKa is extremely sensitive to small variations in structure, especially in the placement of protein backbone atoms near the first cysteine.
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Avouris has been a trailblazer in the nanoscience and nanotechnology field. He pioneered the use of scanning tunneling microscopy and spectroscopy to study surface chemistry on the atomic scale, and establish the relation between chemical reactivity and local electronic structure. He demonstrated device-like behavior on the atomic scale, observed electron confinement and interference effects at surfaces. He also manipulated covalently bonded atoms with atomic precision.
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Zigzag edges are known to be more reactive than armchair edges, as observed in the dehydrogenation reactivities between the compound with zigzag edges (tetracene) and armchair edges (chrysene). Also, zigzag edges tends to be more oxidized than armchair edges without gasification. The zigzag edges with longer length can be more reactive as it can be seen from the dependence of the length of acenes on the reactivity.
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Nowadays, however, the preferred route to acrylic acid entails the oxidation of propene, exploiting its low cost and the high reactivity of the allylic C-H bonds. Hydroesterification is like hydrocarboxylation, but it uses alcohols in place of water.El Ali, B.; Alper, H. "Hydrocarboxylation and hydroesterification reactions catalyzed by transition metal complexes" In Transition Metals for Organic Synthesis, 2nd ed.; Beller, M., Bolm, C., Eds.
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Benzoates and salicylates occur naturally in many foods, including fruits, juices, vegetables, spices, herbs, nuts, tea, wines, and coffee. Salicylate sensitivity causes reactions to not only aspirin and NSAIDs but also foods in which salicylates naturally occur, such as cherries. Other natural chemicals which commonly cause reactions and cross reactivity include amines, nitrates, sulphites and some antioxidants. Chemicals involved in aroma and flavour are often suspect.
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The concept of cone angle is of practical importance in homogeneous catalysis because the size of the ligand affects the reactivity of the attached metal center. In an example, the selectivity of hydroformylation catalysts is strongly influenced by the size of the coligands. Despite being monovalent, some phosphines are large enough to occupy more than half of the coordination sphere of a metal center.
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Haloalkanes containing halogens other than fluorine are more reactive than the parent alkanes—it is this reactivity that is the basis of most controversies. Many are alkylating agents, with primary haloalkanes and those containing heavier halogens being the most active (fluoroalkanes do not act as alkylating agents under normal conditions). The ozone-depleting abilities of the CFCs arises from the photolability of the C–Cl bond.
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According to Ramsay et al., urea fertilization could cause damage to the rich marine biodiversity of the Sulu sea (including its coral reefs). In waters with sufficient iron micro nutrients, but a deficit of nitrogen, urea fertilization is the better choice for algae growth. Urea is the most used fertilizer in the world, due to its high content of nitrogen, low cost and high reactivity towards water.
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Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour.CDC - NIOSH Pocket Guide to Chemical Hazards The most common form of this substance is hexafluoroacetone sesquihydrate (1.5 H2O), which is a hemihydrate of hexafluoropropane-2,2-diol , a geminal diol .
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A highly efficient gold and palladium combined methodology for the Sonogashira coupling of a wide array of electronically and structurally diverse aryl and heteroaryl halides have been reported. The orthogonal reactivity of the two metals shows high selectivity and extreme functional group tolerance in Sonogashira coupling. A brief mechanistic study reveals that the gold-acetylide intermediate enters into palladium catalytic cycle at the transmetalation step.
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Conformations adopted by saccharide molecules in response to the physical forces arising from their bonding and nonbonding electrons, modified by the molecule's interactions with its aqueous or other solvent environment, strongly influence their reactivity with and recognition by other molecules (processes which in turn can alter conformation). Chemical transformations and biological signalling mediated by conformation-dependent molecular recognition between molecules underlie all essential processes in living organisms.
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Isocyanides have diverse reactivity. Isocyanides are stable to strong base (they are often made under strongly basic conditions), but they are sensitive to acid. In the presence of aqueous acid, isocyanides hydrolyse to the corresponding formamides: :RNC + H2O → RN(H)C(O)H This reaction is used to destroy odorous isocyanide mixtures. Some isocyanides can polymerize in the presence of Lewis and Bronsted acids.
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Lawrence et al. found strong inter-rater reliability and test-retest reliability for the EQ. They also found that the EQ has a moderate correlation with the 'empathetic concern’ and ‘perspective taking’ sub-scales of the Interpersonal Reactivity IndexShaw, P., Baker, D., Baron Cohen, S., Lawrence, E. J., & David, A. S. (2004). Measuring empathy: Reliability and validity of the empathy quotient. Psychological Medicine, 34(5), 911–919.
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Cyclic and benzylic ketones are reduced to their respective alcohols. Barbier- type reaction catalysed by Cp2TiCl Bis(cyclopentadienyl)titanium(III) chloride also effects both Pinacol and McMurry couplings of aldehydes and ketones. Barbier-type reactivity is observed between aldehydes or ketones and allyl electrophiles under catalytic conditions. The proposed mechanism involves titanium(III)-mediated generation of an allyl radical species which intercepts a titanium(III)-coordinated carbonyl.
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This kinetic barrier prevents life from bursting into flames at room temperature. Electronic spin states are more complex for transition metals. To understand the reactivity of transition metals, it is essential to understand the concept of d electron configuration as well as high-spin and low-spin configuration. For example, a low-spin d8 transition metal complex is usually square planar substitutionally inert with no unpaired electrons.
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Commonly, commercially available Ni(II) salts are employed in cross-coupling reactions. These salts require reduction to low- valent nickel to obtain the catalytically active Ni(0) or Ni(I) species. Below is a list of common Ni(II) salts and a representative publication utilizing these salts. Empirically, these precatalysts can be used interchangeably, with the effect on yield ranging from quite minor to loss of reactivity.
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N-Sulfinyl imines (N-sulfinylimines, sulfinimines, thiooxime S-oxides) are a class of imines bearing a sulfinyl group attached to nitrogen. These imines display usefully stereoselectivity reactivity and due to the presence of the chiral electron withdrawing N-sulfinyl group. They allow 1,2-addition of organometallic reagents to imines. The N-sulfinyl group exerts powerful and predictable stereodirecting effects resulting in high levels of asymmetric induction.
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With these methods, chemical reactivity, melt viscosity, and wetting between the two components should be considered carefully. Some issues with infiltrating melted Si is that the free Si can lower the composite's resistance to oxidation and creep. However, this technique usually yields lower residual porosity (~5%) compared to the other two techniques due to higher densification rates.Hillig, W. B. (1988), Melt Infiltration Approach to Ceramic Matrix Composites.
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Their absence has been speculatively attributed to the extreme reactivity of such compounds, including the reaction of an initially formed fluoride with the walls of the glass container to form a non-volatile product. Thus, although the synthesis of an astatine fluoride is thought to be possible, it may require a liquid halogen fluoride solvent, as has already been used for the characterization of radon fluoride.
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The highly reactive Cp2ZrII compound possesses one lone electron pair and two vacant valence orbitals. Therefore, it can be compared to carbenes in terms of its reactivity. Typical reactions of in situ generated zirconocenes are coupling or insertion to form metallacycles. These reactions have been observed upon addition of carbon monoxide, ketones, nitriles, alkynes and other substances and led to five-, seven- and nine-membered metallacycles.
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Commonly, the mixture called Schlosser's base is produced by combining n-butyllithium and potassium tert-butoxide in a one-to-one ratio. The high reactivity of Schlosser's base is exploited in synthetic organic chemistry for the preparation of organometallic reagents. For example, potassium benzyl can be prepared from toluene using this reagent. Benzene and cis/trans-2-butene are also readily metalated by Schlosser's base.
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The structures of acceptors play a critical role in the rate and stereoselectivity of glycosylations. Generally, the unprotected hydroxyl groups are less reactive when they are between bulky protecting groups. That is the reason why the hydroxyl group at OH-4 in pyranosides is unreactive. Hyperconjugation is involved when OH-4 is anti-periplanar to the ring oxygen, which can also reduce its reactivity.
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Another unrelated double bond rule exists that relates to the enhanced reactivity of sigma bonds attached to an atom adjacent to a double bond. In bromoalkenes, the C–Br bond is very stable, but in an allyl bromide, this bond is very reactive. Likewise, bromobenzenes are generally inert, whereas benzylic bromides are reactive. The first to observe the phenomenon was Conrad Laar in 1885.
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Parameters such as structure, size distribution, surface area, surface chemistry, surface charge, and agglomeration state as well as purity of the samples, have considerable impact on the reactivity of carbon nanotubes. However, available data clearly show that, under some conditions, nanotubes can cross membrane barriers, which suggests that, if raw materials reach the organs, they can induce harmful effects such as inflammatory and fibrotic reactions.
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They suggest that while robots are unlike humans, they could benefit from strengthened associative connections in their optimization. Also robots could improve through reactivity and sensitivity to environmental stimuli, human-machine interaction, multisensory integration and linguistic input. The embodied approach to AI has been given several names by different schools of researchers, including: Nouvelle AI (Brooks' term), Situated AI, Behavior based AI and Embodied cognitive science.
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Peter Pollak, Gérard Romeder, Ferdinand Hagedorn, Heinz-Peter Gelbke "Nitriles" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. As a bifunctional compound, trichloroacetonitrile can react at both the trichloromethyl and the nitrile group. The electron withdrawing effect of the trichloromethyl group activates the nitrile group for nucleophilic additions. The high reactivity makes trichloroacetonitrile a versatile reagent, but also causes its susceptibility towards hydrolysis.
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Even at relatively low doses of DEHP, cardiovascular reactivity was significantly affected in mice. A clinically relevant dose and duration of exposure to DEHP has been shown to have a significant impact on the behavior of cardiac cells in culture. This includes an uncoupling effect that leads to irregular rhythms in vitro. Untreated cells had fast conduction velocity, along with homogenous activation wave fronts and synchronized beating.
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Greenwood and Earnshaw, pp. 412–16 Given the great reactivity of atomic nitrogen, elemental nitrogen usually occurs as molecular N2, dinitrogen. This molecule is a colourless, odourless, and tasteless diamagnetic gas at standard conditions: it melts at −210 °C and boils at −196 °C. Dinitrogen is mostly unreactive at room temperature, but it will nevertheless react with lithium metal and some transition metal complexes.
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Like phenols, aniline derivatives are highly susceptible to electrophilic substitution reactions. Its high reactivity reflects that it is an enamine, which enhances the electron- donating ability of the ring. For example, reaction of aniline with sulfuric acid at 180 °C produces sulfanilic acid, H2NC6H4SO3H. If bromine water is added to aniline, the bromine water is decolourised and a white precipitate of 2,4,6-tribromoaniline is formed.
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Alkenes are relatively stable compounds, but are more reactive than alkanes, either because of the reactivity of the carbon–carbon pi-bond or the presence of allylic CH centers. Most reactions of alkenes involve additions to this pi bond, forming new single bonds. Alkenes serve as a feedstock for the petrochemical industry because they can participate in a wide variety of reactions, prominently polymerization and alkylation.
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In contrast to the high reactivity and toxicity of , sulfur hexafluoride (), is inert and nontoxic despite having a closely related chemical formula. This difference highlights the lability of the S-Cl bond in this molecule. Under free-radical conditions, adds across double bonds. The following reaction involves the reaction of propene: : + → CH3CH(Cl)CH2SF5 The addition reaction is catalyzed by at around -30 °C.
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All flavonoids are derived from this chalcone backbone (this family being the so-called chalconoids). The activity of different enzymes, including isomerases and hydroxylases, alter the backbone depending on the subclass of the flavonoid being produced. Transferases help control changes in the flavonoid’s solubility and reactivity by catalyzing the addition of things such as methyl groups and sugars. This allows for controlled fluctuations in physiological activities.
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The Fe atom also contains three ligands, one CO and two CN that complete the active site. These additional ligands might contribute to the reactivity or help stabilize the Fe atom in the low spin +2 oxidation state. Typical [NiFe] hydrogenases like those of D. vulgaris and D. gigas are poisoned by oxygen because an oxygen atom binds strongly to the NiFe active site.
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If the reactants have a distribution of velocities, e.g. a thermal distribution, then it is useful to perform an average over the distributions of the product of cross section and velocity. This average is called the 'reactivity', denoted <σv>. The reaction rate (fusions per volume per time) is <σv> times the product of the reactant number densities: :f = n_1 n_2 \langle \sigma v \rangle.
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Jean-Claude Lorquet (born 19 September 1935) is a professor of Theoretical Chemistry at the University of Liège. He is member of the International Academy of Quantum Molecular Science and author of over 100 scientific papers. Some of his students are also well known for their contribution to quantum chemistry and reactivity: Michèle Desouter-Lecomte, Bernard Ley, Françoise Remacle. Lorquet was born in Liège, Belgium.
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Allyl halides are particularly attractive for Sn2-type reactions due to the increased reactivity added by the allyl system. Celestolide (4-acetyl-6-t-butyl-1,1-dimethylindane, a component of musk perfume) can be synthesized using a benzyl anion alkylation with 3-chloro-2-methyl-1-propene as an intermediate step. The synthesis is fairly straightforward, and has been adapted for teaching purposes in an undergraduate laboratory.
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2000, 65, 1158–1174. An example of the catalytic amination of an aryl chloride with N-methylaniline at room temperature. Although the high reactivity of the ligand is not completely understood, Buchwald et al. suggest some structural factors that contribute to their effectiveness: the electron rich phosphine group may help the acceleration of the oxidative addition step,Grushin, V. V.; Alper, H. Chem. Rev.
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A non-burnable poison is one that maintains a constant negative reactivity worth over the life of the core. While no neutron poison is strictly non-burnable, certain materials can be treated as non-burnable poisons under certain conditions. One example is hafnium. It has five stable isotopes through which can all absorb neutrons, so the first four are chemically unchanged by absorbing neutrons.
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Cyclopropanation reactions in natural products synthesis have been reviewed. The β-lactamase inhibitor Cilastatin provides an instructive example of Simmons-Smith reactivity in natural products synthesis. An allyl substituent on the starting material is Simmons-Smith cyclopropanated, and the carboxylic acid is subsequently deprotected via ozonolysis to form the precursor. Simmons-Smith cyclopropanation in cilastatin synthesis The natural product cilastatin, synthesized via a Simmons-Smith cyclopropanation.
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An important practical relevance of the phenomenon is as a type of interference that plagues certain immunoassays and nephelometric assays, resulting in false negatives or inaccurately low results. Other common forms of interference include antibody interference, cross-reactivity and signal interference. The phenomenon is caused by very high concentrations of a particular analyte or antibody and is most prevalent in one-step (sandwich) immunoassays.
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Some nano silver particles develop protective Ag3OH surface groups Molleman, Bastiaan, and Tjisse Hiemstra. "Surface Structure of Silver Nanoparticles as a Model for Understanding the Oxidative Dissolution of Silver Ions." Langmuir 31.49 (2015): 13361-3372. and it is thought that dissolution removes these groups and forms oxygen radicals, which attenuate reactivity of the AgNPs by entering into the lattice to form a highly stable Ag6O octahedral structure.
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Metals tend to form basic oxides, non-metals tend to form acidic oxides, and amphoteric oxides are formed by elements near the boundary between metals and non-metals (metalloids). This reactivity is the basis of many practical processes, such as the extraction of some metals from their ores in the process called hydrometallurgy. Oxides of more electropositive elements tend to be basic. They are called basic anhydrides.
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The family of carboxylic acids contains a carboxyl (-COOH) functional group. Acetic acid, shown here, is an example. The concept of functional groups is central in organic chemistry, both as a means to classify structures and for predicting properties. A functional group is a molecular module, and the reactivity of that functional group is assumed, within limits, to be the same in a variety of molecules.
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The buckled structure can be flattened by suppressing the PJT distortion by increasing the energy gap between the UMO and OMO. This can be done by adding a lithium ion. In addition to its potential compatibility with existing semiconductor techniques, silicene has the advantage that its edges do not exhibit oxygen reactivity. In 2012 several groups independently reported ordered phases on the Ag(111) surface.
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Keepon is currently available for purchase at $30,000, though a price drop is speculated after simpler mechanisms are developed. Furthermore, in response to Keepon's online popularity, a toy version, called the My Keepon, was announced in January 2010 by Wow! Stuff in conjunction with BeatBots. The toy aims to "[capture] the essence of the Keepon character", including its reactivity to touch and ability to dance to music.
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CFCs and HCFCs are used in various applications because of their low toxicity, reactivity and flammability. Every permutation of fluorine, chlorine and hydrogen based on methane and ethane has been examined and most have been commercialized. Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine. Uses include refrigerants, blowing agents, propellants in medicinal applications and degreasing solvents.
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In terms of reactivity and appearance, sodium dichromate and potassium dichromate are very similar. The sodium salt is, however, around twenty times more soluble in water than the potassium salt (49 g/L at 0 °C) and its equivalent weight is also lower, which is often desirable.Freeman, F. "Sodium Dichromate" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. .
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An individual's Junior blood type can be determined by serologic testing, which uses a monoclonal antibody reagent directed against the Jr(a) antigen. DNA testing may be impractical due to the high number of mutations affecting Jr(a) expression. Anti-Jr(a) antibodies are most easily detected by the indirect antiglobulin test, and their reactivity is enhanced by enzyme treatment with ficin or papain.
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In case of multiple carbonyl types in one molecule, one can expect the most electrophilic carbonyl carbon to react first. Acyl chlorides and carboxylic anhydrides react fastest, followed by aldehydes and ketones. Esters react much more slowly and amides are almost completely unreactive due to resonance of the amide nitrogen towards the carbonyl group. This reactivity difference allows chemoselectivity when a reactant contains multiple carbonyl groups.
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Olympus manufactures endoscopic, ultrasound, electrocautery, endotherapy, and cleaning and disinfection equipment. The first flexible Endoscope in the world was co- developed and manufactured by Olympus in Tokyo. Through its comprehensive product range and its reactivity to market innovations, Olympus enjoys a virtual stranglehold of the world market in gastro-intestinal endoscopes. It has roughly 70% share of the global market whose estimated valued at US$2.5 billion.
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The phenoxide anion is a strong nucleophile with a nucleophilicity comparable to the one of carbanions or tertiary amines.. Mayr’s Database of Reactivity Parameters. Retrieved July 10, 2019. It can react at both its oxygen or carbon sites as an ambident nucleophile (see HSAB theory). Generally, oxygen attack of phenoxide anions is kinetically favored, while carbon-attack is thermodynamically preferred (see Thermodynamic versus kinetic reaction control).
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Synthetic zeolites, as other mesoporous materials (e.g. MCM-41), are widely used as catalysts in the petrochemical industry, for instance in fluid catalytic cracking and hydrocracking. Zeolites confine molecules in small spaces, which causes changes in their structure and reactivity. The acidic forms of zeolites prepared are often powerful solid- state solid acids, facilitating a host of acid-catalyzed reactions, such as isomerisation, alkylation, and cracking.
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The reactivity of phosphines matches that of amines with regard to nucleophilicity in the formation of phosphonium salts with the general structure PR4+X−. This property is used in the Appel reaction for converting alcohols to alkyl halides. Phosphines are easily oxidized to the corresponding phosphine oxides, whereas amine oxides are less readily generated. In part for this reason, phosphines are very rarely encountered in nature.
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In addition to the other reactions associated with phosphines, those bearing P-H groups exhibit additional reactivity associated with the P-H bonds. They are readily deprotonated using strong bases to give phosphide anions. Primary and secondary phosphines are generally prepared by reduction of related phosphorus halides or esters. For example, phosphonates are reduced to primary phosphines: Example of reduction of phosphonate ester to a primary phosphine.
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Boron shielding is used as a control for nuclear reactors, taking advantage of its high cross- section for neutron capture. In pressurized water reactors a variable concentration of boronic acid in the cooling water is used as a neutron poison to compensate the variable reactivity of the fuel. When new rods are inserted the concentration of boronic acid is maximal, and is reduced during the lifetime.
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Kant had argued against the assumption of the measurability of conscious processes and made a well-founded, if very short, criticism of the methods of self-observation: regarding method-inherent reactivity, observer error, distorting attitudes of the subject, and the questionable influence of independently thinking people,Immanuel Kant: Anthropologie in pragmatischer Hinsicht. Schriften zur Anthropologie, Geschichtsphilosophie, Politik und Pädagogik. (Immanuel Kant Werkausgabe. Band 6). hrsg.
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Franz studied at Wellesley College and earned her Bachelor's degree in 1995. She was a member of the Wellesley College cross country team. She moved to Massachusetts Institute of Technology for her graduate studies, where she worked under the supervision of Stephen J. Lippard and completed her PhD in 2001. Her research considered the nitric oxide reactivity of manganese, iron and cobalt tropocoronand ligands.
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Now, protease generated primary amines that constitute the prime site of cleavage can be biotinylated and isolated due to their reactivity and analyzed by LC-MS/MS. Non-prime sides sequences left behind must be determined using bioinformatics analysis of the extracted N-termini and full length protein sequences. These prime and non-prime sites give a full picture of protease cleavage site specificity.
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On the periodic table, homologous elements share many electrochemical properties and appear in the same group (column) of the table. For example, all noble gases are colorless, monatomic gases with very low reactivity. These similarities are due to similar structure in their outer shells of valence electrons. Mendeleev used the prefix eka- for an unknown element below a known one in the same group.
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The aerobic enzyme has a structure homologous to the complex alpha/beta topology found in the gene product of human sulfatase- modifying factor 1 (SUMF1). Aerobic FGE converts a cysteine residue in the highly conserved consensus sequence CXPXR to fGly. To do so, FGE “activates” its target by utilizing mononuclear copper. The substrate first binds to copper, increasing reactivity of the substrate-copper complex with oxygen.
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One of the earliest reports of protodeboronation was made by Ainley and Challenger, who were the first researchers to explore the reactivity of boronic acids with common chemical reagents.Ainley, A. D.; Challenger, F. "Studies of the boron-carbon linkage" J. Chem. Soc. 1930, 2171. They reported the reaction of phenylboronic acid in water (140-150 °C) to afford the protodeboronated product, benzene, after 40 hours.
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Dogs with access to the outdoors may introduce outdoor allergens such as mold and pollen with larger animals tracking in more of these allergens. It is well established that most individuals with dog allergy also suffer with additional environmental allergies. Individuals with dog allergy may also be at increased risk for human protein hypersensitivity with cross-reactivity of dog dander allergen and human seminal fluid.
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Mixed acyl-trifluoromethanesulfonyl anhydrides smoothly undergo Friedel-Crafts acylation without a catalyst, unlike the corresponding acyl halides, which require a strong Lewis acid. Methyl triflate, however, does not participate in Friedel-Crafts alkylation reactions with electron-neutral aromatic rings. Beyond super leaving groups in reactivity lie the "hyper" leaving groups. Prominent among these are λ3-iodanes, which include diaryl iodonium salts, and other halonium ions.
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A linear combination of atomic orbitals or LCAO is a quantum superposition of atomic orbitals and a technique for calculating molecular orbitals in quantum chemistry.Huheey, James. Inorganic Chemistry:Principles of Structure and Reactivity In quantum mechanics, electron configurations of atoms are described as wavefunctions. In a mathematical sense, these wave functions are the basis set of functions, the basis functions, which describe the electrons of a given atom.
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Der f 1 is found in the fecal pellets of the American house dust mite Dermatophagoides farinae. Der f 1 is considered a major mite allergen and has been shown to promote allergic reactions in the lungs and skin. Der f 1 shows over 80% cross-reactivity with Der p 1. Like Der p 1, Der f 1 functions by cleaving CD23 to trigger an IgE response.
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In 1920 Wendt and Landauer named the substance "Hyzone" in analogy to ozone and its extra reactivity over normal hydrogen. Earlier Gottfried Wilhelm Osann believed he had discovered a form of hydrogen analogous to ozone which he called "Ozonwasserstoff". It was made by electrolysis of dilute sulfuric acid. In those days no one knew that ozone was triatomic so he did not announce triatomic hydrogen.
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In 1815 Davy suggested that acids were substances that contained replaceable hydrogen ions;– hydrogen that could be partly or totally replaced by reactive metals which are placed above hydrogen in the reactivity series. When acids reacted with metals they formed salts and hydrogen gas. Bases were substances that reacted with acids to form salts and water. These definitions worked well for most of the nineteenth century.
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Recently the Canning Dam has been subjected to considerable cracking of the upper parts of the dam and upper gallery. Investigations have shown that cracking was due to strong AAR (alkali aggregate reactivity) in the concrete. AAR results in swelling of the concrete, which may cause secondary compressive stresses, localised map cracks, and, ultimately structural cracks. In addition, the concrete tensile strength and elasticity significantly decreases.
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B. Chaudret Polyhydrides and Nanoparticles: A 35 year Trip in Organometallic Chemistry Histoire de la Recherche Contemporaine (la Revue pour l'Histoire du CNRS), Tome I, N°2, 2012, pp. 118–125 S. Sabo- Etienne, B. Chaudret, " Chemistry of bis(dihydrogen) ruthenium complexes and of their derivatives ", Coord. Chem. Rev. 1998, 178-180, 381-407 S. Sabo- Etienne, B. Chaudret, "Quantum Mechanical Exchange Coupling in polyhydride and dihydrogen complexes", Chem. Rev.1998, 98, 2077-2091. K. Philippot, B. Chaudret, " Organometallic Approach to the Synthesis and Surface Reactivity of Noble Metal Nanoparticles", Compte-Rendus Acad Sciences 2003, 6, 1019. DOI: 10.1016/j.crci.2003.07.010 B. Chaudret, "Synthesis and Surface Reactivity of Organometallic Nanoparticles", Surface and Interfacial Organometallic Chemistry and Catalysis in Series: Topics in Organometallic Chemistry, Vol. 16 Coperet, Christope; Chaudret, Bruno (Eds.) 2005, pages 233-260. B. Chaudret, "Organometallic approach to nanoparticles synthesis and self-organization", C.R. Physique 2005, 6, 117.
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Puddephatt has conducted pioneering research on synthesis, reactivity and elucidation of mechanisms in the organometallic chemistry of the noble metals, particularly related to the role of organometallic compounds in catalysis and in materials science. He has elucidated the mechanisms of reactions which are fundamental in many homogenous catalytic processes, most notably in studies of oxidative addition and reductive elimination with alkylplatinum and alkyl–gold complexes and of skeletal rearrangements of metallacyclobutane complexes, often called the Puddephatt rearrangement. Remarkable coordinatively unsaturated platinum clusters and platinum–rhenium clusters have been synthesised and shown to be excellent mimics of the surface reactivity, related to heterogeneous catalysis by supported platinum and bimetallic platinum–rhenium catalysts. New, commercially useful organometallic precursors for chemical vapour deposition (CVD) of thin films of metals such as palladium, platinum, silver and gold have been discovered and the fundamental mechanisms of those CVD processes elucidated.
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Certain animal species, and certain individuals within those species, make better candidates for domestication than others because they exhibit certain behavioral characteristics: (1) the size and organization of their social structure; (2) the availability and the degree of selectivity in their choice of mates; (3) the ease and speed with which the parents bond with their young, and the maturity and mobility of the young at birth; (4) the degree of flexibility in diet and habitat tolerance; and (5) responses to humans and new environments, including flight responses and reactivity to external stimuli. Reduced wariness to humans and low reactivity to both humans and other external stimuli are a key pre-adaptation for domestication, and these behaviors are also the primary target of the selective pressures experienced by the animal undergoing domestication. This implies that not all animals can be domesticated, e.g. a wild member of the horse family, the Zebra.
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Reduction in skull size with neoteny - grey wolf and chihuahua skulls The sustained selection for lowered reactivity among mammal domesticates has resulted in profound changes in brain form and function. The larger the size of the brain to begin with and the greater its degree of folding, the greater the degree of brain-size reduction under domestication. Foxes that had been selectively bred for tameness over 40 years had experienced a significant reduction in cranial height and width and by inference in brain size, which supports the hypothesis that brain-size reduction is an early response to the selective pressure for tameness and lowered reactivity that is the universal feature of animal domestication. The most affected portion of the brain in domestic mammals is the limbic system, which in domestic dogs, pigs, and sheep show a 40% reduction in size compared with their wild species.
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Ed. Engl. 1964, 3, 135. ()Huisgen, R.; Gotthardt, H.; Bayer, H. O.; Schaefer, F.C. Angew. Chem. Int. Ed. Engl. 1964, 3, 136. () The Huisgen group followed up with a thorough investigation of the chemical properties, reactivity, and utility of münchnones towards the synthesis of many other products.Gingrich, H. L.; Baum, J. S. In Oxazoles, Chemistry of Heterocyclic Compounds; Turchi, I. J., Ed.; Wiley: New York, 1986; Vol. 45.
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Iodine, methyl iodide, and 1,2-dibromoethane are common activating agents. The use of 1,2-dibromoethane is advantageous as its action can be monitored by the observation of bubbles of ethylene. Furthermore, the side-products are innocuous: : Mg + BrC2H4Br → C2H4 \+ MgBr2 The amount of Mg consumed by these activating agents is usually insignificant. A small amount of mercuric chloride will amalgamate the surface of the metal, enhancing its reactivity.
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According to the Monro- Kellie doctrine, less cerebral blood volume leads to a reduction in the intracranial pressure. If the blood pressure instead would decrease, the cerebral vessels would vasodilatate, with a resulting increase in cerebral blood volume.Donnelly J, Czosnyka M, Adams H, Robba C, Steiner LA, Cardim D. Pressure Reactivity-Based Optimal Cerebral Perfusion Pressure in a Traumatic Brain Injury Cohort. Acta Neurochir Suppl. 2018; 126:209-212.
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Some results show that cisplatin and carboplatin cause different morphological changes in MCF-7 cell lines while exerting their cytotoxic behaviour. The diminished reactivity limits protein- carboplatin complexes, which are excreted. The lower excretion rate of carboplatin means that more is retained in the body, and hence its effects are longer lasting (a retention half-life of 30 hours for carboplatin, compared to 1.5-3.6 hours in the case of cisplatin).
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Caffeine's widespread appeal is due primarily to its mild psychostimulant properties, which increase alertness and cognitive arousal and diminish fatigue. Caffeine also produces a wide range of other symptoms, including upregulation of the cardiovascular system, increased global cognitive processing, and improved physical functioning. Cardiovascular effects can range from increased heart rate and reactivity to severe cardiac arrhythmia. The cognitive effects of caffeine include increased performance in memory, attention, and text reading.
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An agent is an autonomous entity having a set of skills to realize the capacities it exhibits. An agent has a set of built-in capacities considered essential to respect the commonly accepted competences of agents, such autonomy, reactivity, proactivity and social capacities. Among these built-in capacities (BIC), is the "behaviors" capacity that determines its global conduct. An agent has also a default behavior directly described within its definition.
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Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often displaying unusual conformations and because of their unusual reactivity. Tricyclobutabenzenes are isomers of radialenes and form an equilibrium with them. The parent tricyclobutabenzene (C12H12) was first synthesised in 1979Tricyclobutabenzene Wutichai Nutakul, Randolph P. Thummel, Austin D. Taggart J.
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Like TiCl4 and TiBr4, TiI4 forms adducts with Lewis bases, and it can also be reduced. When the reduction is conducted in the presence of Ti metal, one obtains polymeric Ti(III) and Ti(II) derivatives such as CsTi2I7 and the chain CsTiI3, respectively. TiI4 exhibits extensive reactivity toward alkenes and alkynes resulting in organoiodine derivatives. It also effects pinacol couplings and other C-C bond-forming reactions.
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Academic research into the affect of levels of arousal on instances of challenging behavior have proposed that sensory reactivity is associated with hyper-arousal, and that hypo-arousal can lead to catatonic-type behaviors McDonnell et al., (2015). Low arousal approaches are hypothesized as a generalized strategy to managing behaviors of concern associated with over and under arousal. Studies have been published that directly examine the application of these approaches.
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Styrene reacts in toluene with sodium to 1,3-diphenylpropane Sodium-catalyzed Side Chain Aralkylation of Alkylbenzenes with Styrene Herman Pines, Dieter Wunderlich J. Am. Chem. Soc.; 1958; 80(22)6001–6004. through the intermediate carbanion: :Reaction of styrene with sodium in toluene Another exception to the rule is found in the Varrentrapp reaction. Fullerenes have unusual double bond reactivity and additions such has the Bingel reaction are more frequent.
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Rao began his academic career in 1980 as an Assistant Lecturer at BITS-Pilani, Pilani Campus, Rajasthan. He was later promoted as Assistant Professor, Associate Professor and Professor, in 1982, 1990 and 1995 respectively. The courses taught by him included Organic Chemistry, Structure and Reactivity of Organic Compounds, Synthetic Organic Chemistry, and Stereo Chemistry and Reaction Mechanisms. In addition to academic responsibilities, Rao also held offices in administrative capabilities.
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Nanotoxicology is the field which studies potential health risks of nanomaterials. The extremely small size of nanomaterials means that they are much more readily taken up by the human body than larger sized particles. How these nanoparticles behave inside the organism is one of the significant issues that needs to be resolved. The behavior of nanoparticles is a function of their size, shape and surface reactivity with the surrounding tissue.
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The condensation of water droplets in the mushroom cloud depends on the amount of condensation nuclei. Too many condensation nuclei actually inhibit condensation, as the particles compete for a relatively insufficient amount of water vapor. Chemical reactivity of the elements and their oxides, ion adsorption properties, and compound solubility influence particle distribution in the environment after deposition from the atmosphere. Bioaccumulation influences the propagation of fallout radioisotopes in the biosphere.
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Lithium reacts with water easily, but with noticeably less vigor than other alkali metals. The reaction forms hydrogen gas and lithium hydroxide in aqueous solution. Because of its reactivity with water, lithium is usually stored in a hydrocarbon sealant, often petroleum jelly. Though the heavier alkali metals can be stored in denser substances such as mineral oil, lithium is not dense enough to fully submerge itself in these liquids.
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This provides for the first time conclusive experimental evidence for the proposed mechanism of borepine formation from boroles and alkynes. However, the reaction of 2 with diphenylacetylene gave unexpected results. Similar to the observations described for 3-hexyne, the electron rich PhCCPh facilitated a spontaneous reaction. Surprisingly, the diphenyl-substituted heptaarylborepine isomers 6 formed by the common Diels–Alder reactivity represented only minor components of the product mixture (25%).
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In comparison to the MBH reaction, the RC reaction lacks substrate reactivity and reaction selectivity. The original 1963 reaction described the dimerization of the ethyl acrylate to the ethyl diester of 2-methylene-glutaric acid with tributylphosphine in acetonitrile: Rauhut–Currier reaction This reaction was also found to work for acrylonitrile. RC cross-couplings are known but suffer from lack of selectivity. Amines such as DABCO can also act as catalyst.
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IL30 plays an important role in regulating prostate cancer stem-like cell behavior and metastatic potential. Hence targeting IL-30 signaling may be a potential therapeutic strategy against prostate cancer progression and recurrence. Targeting IL-30 in both cancer and host environment consistently inhibits tumor growth, ameliorates immune reactivity and reduces the risks of disease recurrence. Studies suggested therapeutic monoclonal antibodies against IL-30 as a for cancer treatment.
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They reported the first synthesis of a three-coordinate iron-fluoride complex.Vela, J.; Smith, J; Yu, Y.; Ketterer, N.; Flaschenriem, C.; Lachicotte, R.; Holland, P. Synthesis and reactivity of low-coordinate iron (II) fluoride complexes and their use in the catalytic hydrodefluorination of fluorocarbons. J. Am. Chem. Soc. 2005, 127, 7857-7870 Hydrodefluorination of fluorinated alkenes Jayant and his coworkers developed two phase systems for dehalogenation of trichloroethenes.
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Since 1997, she has built a unique high temperature calorimetry facility. She has also designed and enhanced the instrumentation. Navrotsky introduced and applied the method for measuring the energetics of crystalline oxides of glasses, amorphous, nanophase material, porous materials of hydrous phases and carbonates also more recently nitrides and oxynitrides. Obtaining the thermo chemical data is used to understand the compatibility and reactivity of materials in technological and geological application.
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Both chlorine and bromine are used as disinfectants for drinking water, swimming pools, fresh wounds, spas, dishes, and surfaces. They kill bacteria and other potentially harmful microorganisms through a process known as sterilization. Their reactivity is also put to use in bleaching. Sodium hypochlorite, which is produced from chlorine, is the active ingredient of most fabric bleaches, and chlorine- derived bleaches are used in the production of some paper products.
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The remarkable reactivity and substrate promiscuity of P450s have long attracted the attention of chemists. Recent progress towards realizing the potential of using P450s towards difficult oxidations have included: (i) eliminating the need for natural co-factors by replacing them with inexpensive peroxide containing molecules, (ii) exploring the compatibility of P450s with organic solvents, and (iii) the use of small, non- chiral auxiliaries to predictably direct P450 oxidation.
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Na(silox) is usually prepared by deprotonation of the silanol (t-Bu)3SiOH, which is prepared by a multistep route via the intermediacy of (t-Bu)2SiF2.Edward M. Dexheimer and Leornard Spialter, Lee D. Smithson "Tri-t-butylsilane: synthesis, physical properties, derivatives, and reactivity towards ozonolysis, chlorination, fluorination, and hydrolysis" Journal of Organometallic Chemistry 102, 1975, 21-27.. It is also obtained by treatment of tBu3SiNa with nitrous oxide.
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Because of its great reactivity, all chlorine in the Earth's crust is in the form of ionic chloride compounds, which includes table salt. It is the second-most abundant halogen (after fluorine) and twenty-first most abundant chemical element in Earth's crust. These crustal deposits are nevertheless dwarfed by the huge reserves of chloride in seawater. Elemental chlorine is commercially produced from brine by electrolysis, predominantly in the chlor-alkali process.
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DMAN enables an improved reactivity of unforeseen events and can therefore reduce the negative impact of such an event (e.g. instantaneous runway closure due to suspected debris, weather changes etc.). By constantly monitoring and distributing information the DMAN can support the ATC in an airport to make a new plan based on the current situation and quickly distribute the information to the different operators and stakeholders at the airport.
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Jerry March Substituted cyclopropanes can oxidatively add to transition metals, in a process referred to as C–C activation. :Electrophilic addition of HBr to cyclopropane Cyclopropyl groups adjacent to vinyl groups can undergo ring expansion reactions. Examples include the vinylcyclopropane rearrangement and the divinylcyclopropane-cycloheptadiene rearrangement. This reactivity can be exploited to generate unusual cyclic compounds, such as cyclobutenes, or bicyclic species such as the cycloheptene shown below.
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It is known that the reactivity of the monomer is lower than it could be, since the contained ester group can react with the reactive, polymerizing chain end and stabilize it. It therefore reacts significantly slower than other molecules without ester group. ECC polymerizes also much slower than radical monomers. It is therefore the object of research to find cationic polymerizable monomers with higher polymerization rate but same performance.
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People might also find that cross-reactivity occurs. For example, people allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food.
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As with any functional group, the hazards of halohydrins are difficult to generalize as they may form part of an almost limitless series of compounds, with each structure having different pharmacology. In general, simpler low molecular weight compounds are often toxic and carcinogenic (e.g. 2-chloroethanol, 3-MCPD) by virtue of being alkylating agents. This reactivity can be put to good use, for instance in the anti-cancer drug mitobronitol.
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Cram described the interior of the container compound as the inner phase in which radically different reactivity was observed.The Inner Phase of Molecular Container Compounds as a Novel Reaction Environment Ralf Warmuth Journal of Inclusion Phenomena and Macrocyclic Chemistry 37: 1–38, 2000. He used a hemicarcerand to isolate highly unstable, antiaromatic cylobutadiene at room temperature. The hemicarcerand stabilizes guests within its cavity by preventing their reaction with other molecules...
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She also investigates nucleophilic attack of MnV-oxo due to hydroxyl groups on the OEC. The small molecules include nitrogen and sulphur and a particular stereochemistry. Through synthesis of organic molecules with a variety of different molecular frameworks, Kovacs investigates their structure-property relationships and the reactivity of the resulting transition-metal complexes. Kovacs was elected President of the American Chemical Society Division on Inorganic Chemistry in 2019.
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Stationary phases are available in many varieties of packing styles as well as chemical structures and can be functionalized for added specificity. Monolithic-style columns, or monoliths, are one of many types of stationary phase structure. Monoliths, in chromatographic terms, are porous rod structures characterized by mesopores and macropores. These pores provide monoliths with high permeability, a large number of channels, and a high surface area available for reactivity.
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Within this field, he worked on complex chemical reactions, radio chemistry, and spectroscopy. In the 1950s, he was interested in the chemistry of poly-sulfides and selenium (his PhD was on the subject of selenium). At the end of the 1950s, he shifted his interest to solutions kinetic properties with nonlinear reactions. Here he contributed significantly to the understanding of the relationship between the spatial structure of molecules and their reactivity.
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TMEDA has an affinity for lithium ions. When mixed with n-butyllithium, TMEDA's nitrogen atoms coordinate to the lithium, forming a cluster of higher reactivity than the tetramer or hexamer that n-butyllithium normally adopts. BuLi/TMEDA is able to metallate or even doubly metallate many substrates including benzene, furan, thiophene, N-alkylpyrroles, and ferrocene. Many anionic organometallic complexes have been isolated as their [Li(tmeda)2]+ complexes.
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This is an important difference from other Reaction Injection Moulding (RIM) systems like polyurethane, since the reaction is not stoichiometric. The 1:1 ratio for DCPD moulding is not critical since this is not a combination of two different chemical elements to form a specific matrix. Significant changes in ratio will slow down the system's reactivity because fewer active reaction nuclei are being formed. This also changes the final properties somewhat.
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Field effect on a carbonyl arising from the formal charge on N in a quaternary ammonium salt. A field effect is the polarization of a molecule through space. The effect is a result of an electric field produced by charge localization in a molecule. This field, which is substituent and conformation dependent, can influence structure and reactivity by manipulating the location of electron density in bonds and/or the overall molecule.
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The para-nitrobenzoate, bistriflimide, and certain nitrile complexes represent catalytically active yet isolable silver-free precatalysts. Cationic gold(I) forms π-complexes with alkene or alkyne bonds, following the Dewar–Chatt–Duncanson model. Gold is certainly not the only metal showing this type of bonding and reactivity, several metal ions isolobal with the simple proton (i.e., an empty s-orbital) do as well: for example, mercury(II) and platinum(II).
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Determining the impact of a nanoparticle on a living system is not straightforward. A multitude of in vivo and in vitro studies must be done to fully characterize reactivity. In vivo studies often use whole organisms such as mice or zebrafish to infer the interaction of the nanoparticle on a healthy human body. In vitro studies look at how nanoparticles interact with specific cell colonies, typically of human origin.
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FEP is produced by free-radical polymerization of mixtures of tetrafluoroethylene and hexafluoropropylene. The mixture is biased to compensate for the relatively low reactivity of the propylene component. The process is typically initiated with peroxydisulfate, which homolyzes to generate sulfate radicals. Because FEP is poorly soluble in almost all solvents, the polymerization is conducted as an emulsion in water, often using a surfactant such as perfluorooctanesulfonic acid (PFOS).
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Sulser F., Vetulani J.: Action of various antidepressant treatments reduces reactivity of noradrenergic cyclic AMP generating system in limbic forebrain, Nature, 257, 1975. He was made Professor Emeritus of the University in 2000. Sulser received several honors during his research career, including the Anna-Monika Prize. He was a Fellow and President of the American College of Neuropsychopharmacology as well as a Fellow of the Collegium International Neuro-Psychopharmacologium.
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The reactor core is 1.03 meters tall with a diameter of 2.05 meters. It has 369 fuel assemblies, mounted vertically, each consisting of 127 fuel rods enriched to between 17-26% 235U. In comparison, normal enrichment in other Russian reactors is between 3-4% 235U. The control and scram system comprises 27 reactivity control elements including 19 shimming rods, two automatic control rods, and six automatic emergency shut-down rods.
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Since bent metallocenes typically have other ligands, often halides, these additional sites are centers of reactivity. For example, reduction of zirconacene dichloride gives the corresponding hydrido chloride called Schwartz's reagent: :(C5H5)2ZrCl2 \+ 1/4 LiAlH4 → (C5H5)2ZrHCl + 1/4 "LiAlCl4" This hydride reagent is useful for organic synthesis. Related titanium-based complexes Petasis reagent and Tebbe's reagent also feature bent metallocenes. Titanocene pentasulfide is used in research on polysulfur rings.
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However, low concentrations of a radical scavenger establish thermodynamic control and provide access to 6-endo products—not via 6-endo cyclization, but by 5-exo cyclization followed by 3-exo closure and subsequent fragmentation (Dowd-Beckwith rearrangement). Whereas at high concentrations of the exo product is rapidly trapped preventing subsequent rearrangement to the endo productBeckwith, A.; O'Shea, D. Tetrahedron Lett. 1986, 27, 4525. Aryl radicals exhibit similar reactivity.
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Jean-Michel Savéant’s scientific activity is outlined by the foundation and development of a new discipline - molecular electrochemistry. Molecular electrochemistry has transferred the knowledge acquired by electrochemistry towards various fields of chemistry and biochemistry, in particular towards the chemistry of electron and proton transfer, free radical chemistry, chemical reactivity theory, coordination chemistry, photochemistry, solid physico-chemistry, enzymology and catalytic activation of small molecules, especially those involved in solving contemporary energy challenges.
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The surface modification of nanocellulose is currently receiving a large amount of attention. Nanocellulose displays a high concentration of hydroxyl groups at the surface which can be reacted. However, hydrogen bonding strongly affects the reactivity of the surface hydroxyl groups. In addition, impurities at the surface of nanocellulose such as glucosidic and lignin fragments need to be removed before surface modification to obtain acceptable reproducibility between different batches.
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This primary antibody could also be in the serum of a donor to be tested for reactivity towards the antigen. # Enzyme- linked secondary antibodies are applied as detection antibodies that also bind specifically to the antibody's Fc region (nonspecific). # The plate is washed to remove the unbound antibody-enzyme conjugates. # A chemical is added to be converted by the enzyme into a color or fluorescent or electrochemical signal.
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The alkali metals, due to their high reactivity, do not occur naturally in pure form in nature. They are lithophiles and therefore remain close to the Earth's surface because they combine readily with oxygen and so associate strongly with silica, forming relatively low-density minerals that do not sink down into the Earth's core. Potassium, rubidium and caesium are also incompatible elements due to their large ionic radii.
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Substances called vasoconstrictors reduce the caliber of blood vessels, thereby increasing blood pressure. Vasodilators (such as nitroglycerin) increase the caliber of blood vessels, thereby decreasing arterial pressure. In the longer term a process termed remodeling also contributes to changing the caliber of small blood vessels and influencing resistance and reactivity to vasoactive agents. Reductions in capillary density, termed capillary rarefaction, may also contribute to increased resistance in some circumstances.
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This new structure has been shown to have electronic properties that differ from those of fullerenes and carbon nanotubes (CNTs). CNBs exhibit lower field thresholds and higher current densities and electric field emission than SWCNTs. The chemical bonds between the nanotube's wall and the fullerenes on the surface can lead to charge transfer between the surfaces. The presence of fullerenes in CNBs lead to smaller bundle formation and larger chemical reactivity.
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Ethylene oxide is isomeric with acetaldehyde and with vinyl alcohol. Ethylene oxide is industrially produced by oxidation of ethylene in the presence of silver catalyst. The reactivity that is responsible for many of ethylene oxide's hazards also make it useful. Although too dangerous for direct household use and generally unfamiliar to consumers, ethylene oxide is used for making many consumer products as well as non-consumer chemicals and intermediates.
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4-hydroxybenzoate 3-monooxygenase is a homodimer with a flavin bound to each monomer. The active site is composed of the flavin and amino acids on the monomer. The structure of this enzyme often serves as a model for structure-reactivity interdependence of other flavin- dependent hydroxylases. The active site limits potential substrates to substituted benzenes, namely 4-hydroxybenzoate (the native substrate), 2,4-dihydroxybenzoate, 4-mercaptobenzoate, and several halogenated aromatic compounds.
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The resulting field of crystal topography is used extensively in studies involving crystal growth and solid-state reactivity. Ramachandran then spent two years (1947–1949) at the Cavendish Laboratory in Cambridge, where he earned his PhD for 'studies on X-ray diffuse scattering and its application to determination of elastic constants' under the direction of Professor William Alfred Wooster, popularly known as W.A. Wooster, a leading crystallography expert in the world.
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Reported side effects include injection site reactions, rash, and rarely toxic epidermal necrolysis. Gastrointestinal side effects generally include diarrhea and nausea and vomiting. There may be drug-induced eosinophilia. Because of the unfused beta- lactam ring there is somewhat lower cross-reactivity between aztreonam and many other beta-lactam antibiotics, and it may be safe to administer aztreonam to many patients with hypersensitivity (allergies) to penicillins and nearly all cephalosporins.
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Because of their reactivity and instability, alkanesulfinyl chlorides are generally used without purification immediately after their synthesis. Storage is not recommended since pressure develops within the container due to hydrogen chloride release. Treatment of alkanesulfinyl chlorides having α-hydrogens with tertiary amine bases gives thiocarbonyl S-oxides (sulfines) as isolable compounds. Thus, treatment of n-propanesulfinyl chloride with triethylamine gives syn-propanethial-S-oxide, the lachrymatory agent of the onion.
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Zubler and Mosby Illuminating Engineering 1959 54.734 Quite soon, bromine was found to have advantages, but was not used in elemental form. Certain hydrocarbon bromine compounds gave good results.T'Jampens and van der Weijer Philips Technical Review 1966 27.173 Regeneration of the filament is also possible with fluorine, but its chemical reactivity is so great that other parts of the lamp are attacked.Burgin and Edwards Lighting Research and Technology 1970 2.2.
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Jarrold serves as a professor, researcher, and chair for the Department of Chemistry at Indiana University. Her research utilizes the applications of gas-phase reactivity, mass spectrometry, anion photodetachment spectroscopies, and computational chemistry, and her research focuses on: design an optimization of heterogeneous catalysts with lower operating temperatures, oxidation of volatile organic compounds in atmospheric reaction complexes and exploration of electronic structures that arise in heteronuclear lanthanide complexes.
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Metals in the first group of the periodic table are small, but they are too reactive. So there needs to be a compromise between the reactivity of chemicals and size. That is why materials like Cu or Ag fulfill the needs of the nanoionic drives. In the nanoionic device there would be chalcogenide glass with has the metal like gold and an element for group six infused in the glass.
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J. Am. Chem. Soc. 129 (5): 1024-1025. . frameless Although the reaction is still under thermodynamic control, an initial kinetic product, which may be dimerization or oligomerization of the starting material, is formed at the onset of the reaction as a result of higher catalyst reactivity. Increased catalyst activity also allows for the olefin products to reenter the catalytic cycle via non-terminal alkene addition onto the catalyst.
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Jack Richard Norton (born May 5, 1945) is an American organometallic chemist and Professor at Columbia University. His research has focused on the studying the reactivity and properties of transition metal hydrides. He coauthored the textbook "Principles and Applications of Organotransition Metal Chemistry."Collman, J. P., Hegedus, L. S., Norton, J. R., Finke, R. G., "Principles and Applications of Organotransition Metal Chemistry," University Science Books: Mill Valley, 1987.
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La is involved in diverse aspects of RNA metabolism, including binding and protecting 3-prime UUU (OH) elements of newly RNA polymerase III-transcribed RNA, processing 5-prime and 3-prime ends of pre-tRNA precursors, acting as an RNA chaperone, and binding viral RNAs associated with hepatitis C virus. La protein was originally defined by its reactivity with autoantibodies from patients with Sjögren's syndrome and systemic lupus erythematosus.
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Julia Ann Kalow is an Assistant Professor of Chemistry at Northwestern University. She is primarily a synthetic chemist, who works on polymers, photochemistry and tissue engineering. She is interested in synthetic strategies that can turn molecular structure and chemical reactivity into macroscopic properties. She has been awarded the National Science Foundation CAREER Award, Thieme Award and was selected by the University of Chicago as a Rising Star in Chemistry.
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Anions that interact weakly with cations are termed non-coordinating anions, although a more accurate term is weakly coordinating anion. Non-coordinating anions are useful in studying the reactivity of electrophilic cations. They are commonly found as counterions for cationic metal complexes with an unsaturated coordination sphere. These special anions are essential components of homogeneous olefin polymerisation catalysts, where the active catalyst is a coordinatively unsaturated, cationic transition metal complex.
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Surface area is an important metric for engineered nanoparticles because it influences reactivity and surface interactions with ligands. Specific surface area refers to the surface area of a powder normalized to mass or volume. Different methods measure different aspects of surface area. Direct measurement of nanoparticle surface area utilizes adsorption of an inert gas such as nitrogen or krypton under varying conditions of pressure to form a monolayer of gas coverage.
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One of the great draws of the Meerwein–Ponndorf–Verley reduction is its chemoselectivity. Aldehydes are reduced before ketones allowing for a measure of control over the reaction. If it is necessary to reduce one carbonyl in the presence of another, the common carbonyl protecting groups may be employed. Groups, such as alkenes and alkynes, that normally pose a problem for reduction by other means have no reactivity under these conditions.
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GaBr3 is used as a catalyst in organic synthesis, with similar mechanism to GaCl3. However, due to its greater reactivity, it is sometimes disfavored because of the greater versatility of GaCl3. GaBr3 as well as other gallium trihalides and group 13 metal trihalides can be used as catalysts in the oxidative addition of organic compounds. It has been verified that the GaBr3 dimer cleaves unevenly into [GaBr4]− and [GaBr2]+.
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With Pt emissions expecting to rise as a result of increased demand for platinum metals as well as expanded mining activity in the Bushveld Igneous Complex, further research is needed to determine the environmental impacts. Classical purification methods exploit differences in chemical reactivity and solubility of several compounds of the metals under extraction. These approaches have yielded to new technologies that utilize solvent extraction. Separation begins with dissolution of the sample.
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When dealing with low exposure levels, HCCPD reactivity makes the chance of reactive species in the blood at high concentrations very low. However, at higher doses the probability of transporting reactive material across the blood-brain barrier is higher. Short-term inhalation of HCCPD is lethal to mice, rats, rabbits and guinea pigs. The lethality of the animals can be affected by the concentration and duration of HCCPD exposure.
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Therefore, rather than being a passive antibody therapy, Racotumomab acts as a therapeutic vaccine. In melanoma, breast, and lung cancer patients, Racotumomab was able to elicit a specific immune response that recognized and directly killed tumor cells expressing the neoantigen by a mechanism of oncotic necrosis. The specific expression of NGcGM3 in malignant cells reduces the potential risk of an immune cross-reactivity that could cause serious adverse effects.
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In the early development of the technique, chemical motifs have to fulfill criteria of biocompatibility and selective reactivity in order to qualify as bioorthogonal chemical reporters. Some combinations of proteinogenic amino acid side chains meet the criteria, as do ketones and aldehydes (which can tag proteins and some metabolites). Azides and alkynes are other examples of chemical reporters. A bioorthogonal chemical reporter must be incorporated into a biomolecule.
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This equation's factors are roughly in order of potential occurrence for a fission born neutron during critical operation. As already mentioned before, k = (Neutrons produced in one generation)/(Neutrons produced in the previous generation). In other words, when the reactor is critical, k = 1; when the reactor is subcritical, k < 1; and when the reactor is supercritical, k > 1. Reactivity is an expression of the departure from criticality.
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Barium is a chemical element with the symbol Ba and atomic number 56\. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. The most common minerals of barium are barite (now called baryte) (barium sulfate, BaSO4) and witherite (barium carbonate, BaCO3), both insoluble in water.
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Because of the high reactivity of the metal, toxicological data are available only for compounds. Soluble barium compounds are poisonous. In low doses, barium ions act as a muscle stimulant, and higher doses affect the nervous system, causing cardiac irregularities, tremors, weakness, anxiety, shortness of breath, and paralysis. This toxicity may be caused by Ba2+ blocking potassium ion channels, which are critical to the proper function of the nervous system.
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1-Hexene (hex-1-ene) is an organic compound with the formula C6H12. It is an alkene that is classified in industry as higher olefin and an alpha-olefin, the latter term meaning that the double bond is located at the alpha (primary) position, endowing the compound with higher reactivity and thus useful chemical properties. 1-Hexene is an industrially significant linear alpha olefin. 1-Hexene is a colourless liquid.
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Alpha-olefins (or α-olefins) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula CxH2x, distinguished by having a double bond at the primary or alpha (α) position.Petrochemicals in Nontechnical Language, 3rd Edition, Donald L. Burdick and William L. Leffler, This location of a double bond enhances the reactivity of the compound and makes it useful for a number of applications.
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Spontaneous gradient polymerization is due to a difference in reactivity of the monomers. The resulting change in composition throughout the polymerization creates an inconsistent gradient along the polymer. Forced gradient polymerization involves varying the comonomer composition of the feed being throughout the reaction time. Because the rate of addition of the second monomer influences the polymerization and therefore properties of the formed polymer, continuous information about the polymer composition is vital.
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The observer-expectancy effect (also called the experimenter-expectancy effect, expectancy bias, observer effect, or experimenter effect) is a form of reactivity in which a researcher's cognitive bias causes them to subconsciously influence the participants of an experiment. Confirmation bias can lead to the experimenter interpreting results incorrectly because of the tendency to look for information that conforms to their hypothesis, and overlook information that argues against it.Goldstein, Bruce. "Cognitive Psychology".
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In accordance with clinical and personality perspectives, variations in self- complexity are suggested to be factors that either contribute to, or protect against damages to individuals’ physical and mental well-being. In particular, individual differences in self-complexity are predictive of emotional stability and reactivity to stress,Rafaeli-Mor, E., Gotlib, I.H., & Revelle, W. (1998). The meaning and measurement of self-complexity. Personality and Individual Differences, 27(2), 341-356.
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DMS is also taken up by marine bacteria, but not as rapidly as methanethiol. Although DMS usually consists of less than 25% of the volatile breakdown products of DMSP, the high reactivity of methanethiol makes the steady-state DMS concentrations in seawater approximately 10 times those of methanethiol (~3 nM vs. ~0.3 nM). Curiously, there have never been any published correlations between the concentrations of DMS and methanethiol.
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Nylon 6 can be modified using comonomers or stabilizers during polymerization to introduce new chain end or functional groups, which changes the reactivity and chemical properties. It's often done to change its dyeability or flame retardance."Synthesis of Modified Polyamides (Nylon 6)", NPTEL (National Programme On Technology Enhanced Learning), retrieved May 9, 2016 Nylon 6 is synthesized by ring-opening polymerization of caprolactam. Caprolactam has 6 carbons, hence Nylon 6.
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Hevein is the main IgE-binding epitope of the major latex allergen prohevein as are hevein-like protein domains in fruit class I chitinases. Therefore it is a possible cause for allergen cross-reactivity between latex and banana or other fruits like chestnuts or avocadoes. Hevein-like genes can be found in many plants including Arabidopsis thaliana. Hevein is called Hev b 6 under the WHO allergen nomenclature.
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The dysregulation model is supported by neuroanatomical, physiological, and subjective self-report studies. Emotional brain regions (e.g. the amygdala) have shown 60% greater reactivity to emotionally negative photographs following one night of sleep deprivation, as measured by functional magnetic resonance imaging. Five days of sleep restriction (four hour sleep opportunity per night) caused a decrease in connectivity with cortical brain regions involved in the regulation of the amygdala.
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Jeehiun Katherine Lee is an organic chemist and a Professor in the Department of Chemistry at Rutgers University. She currently runs a research lab on the New Brunswick campus.Jeehiun Lee’s website at Rutgers University Professor Jeehiun Katherine Lee, Rutgers University Although she is an organic chemist by training, she has expanded her research field to biological chemistry, using mass spectrometry, computer modeling and other methods to characterize reactivity and catalysis.
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The imidazole ring of the NHC ligand is angled away from the metal center, yet the substituents at the 1,3 positions of the imidazole ring are angled towards it. The presence of the ligand inside of the metal coordination sphere affects the metal reactivity. In terms of electronic effects, NHC are often stronger sigma donation. Second generation Grubbs catalyst is a transition metal NHC complex, is useful for alkene metathesis reactions.
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However, both the Swain–Scott equation and the Brønsted relationship make the rather inaccurate assumption that all nucleophiles have the same reactivity with respect to a specific reaction site. There are several different categories of nucleophiles with different attacking atoms (e.g. oxygen, carbon, nitrogen) and each of these atoms has different nucleophilic characteristics. The Edwards equation attempts to account for this additional parameter by introducing a polarizability term.
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In Suzuki-Miyaura cross-couplings, the traditional coupling partners are organobromides and organoboron compounds. While Suzuki-Miyaura cross-couplings typically employ organobromides as coupling partners, organochlorides are more desirous electrophiles for cross-coupling due to their lower cost. The sluggish reactivity of the C-Cl bond is often a problem. With the advent of Pd-NHC complexes, organochlorides have emerged as viable partners in Suzuki- Miyaura cross coupling.
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The cross-reactivity of IgY with proteins from mammals is also markedly less than that of IgG. Furthermore, the immune response against certain antigens in chickens is more strongly expressed than in rabbits or other mammals. Of the immunoglobulins arising during the immune response, only IgY is found in chicken eggs. Thus, in preparations from chicken eggs, there is no contamination with Immunoglobulin A (IgA) or Immunoglobulin M (IgM).
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People with clinically confirmed tree nut allergy to one type of tree nut may have cross-reactivity to other tree nut species and also to peanuts, which are not nuts but rather part of the legume family. The cause is similarity in protein structures. Identifiable allergenic proteins are grouped into families: cupins, prolamins, profilin and others. Tree nuts have proteins in these families, as do peanuts and other legumes.
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In coordination chemistry, a spectator ligand is a ligand that does not participate in chemical reactions of the complex. Instead, spectator ligands (vs "actor ligands") occupy coordination sites. Spectator ligands tend to be of polydentate, such that the M-spectator ensemble is inert kinetically. Although they do not participate in reactions of the metal, spectator ligands influence the reactivity of the metal center to which they are bound.
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A negative void coefficient means that the reactivity decreases as the void content inside the reactor increases - but it also means that the reactivity increases if the void content inside the reactor is reduced. In boiling-water reactors with large negative void coefficients, a sudden pressure rise (caused, for example, by unplanned closure of a streamline valve) will result in a sudden decrease in void content: the increased pressure will cause some of the steam bubbles to condense ("collapse"); and the thermal output will possibly increase until it is terminated by safety systems, by increased void formation due to the higher power, or, possibly, by system or component failures that relieve pressure, causing void content to increase and power to decrease. Boiling water reactors are all designed (and required) to handle this type of transient. On the other hand, if a reactor is designed to operate with no voids at all, a large negative void coefficient may serve as a safety system.
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Insulin is often measured in serum, plasma or blood in order to monitor therapy in people who are diabetic, confirm a diagnosis of poisoning in hospitalized persons or assist in a medicolegal investigation of suspicious death. Interpretation of the resulting insulin concentrations is complex, given the numerous types of insulin available, various routes of administration, the presence of anti- insulin antibodies in insulin-dependent diabetics and the ex vivo instability of the drug. Other potential confounding factors include the wide-ranging cross-reactivity of commercial insulin immunoassays for the biosynthetic insulin analogs, the use of high-dose intravenous insulin as an antidote to antihypertensive drug overdosage and postmortem redistribution of insulin within the body. The use of a chromatographic technique for insulin assay may be preferable to immunoassay in some circumstances, to avoid the issue of cross-reactivity affecting the quantitative result and also to assist identifying the specific type of insulin in the specimen.
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BVMOs have been widely studied due to their potential as biocatalysts, that is, for an application in organic synthesis. Considering the environmental concerns for most of the chemical catalysts, the use of enzymes is considered a greener alternative. BVMOs in particular are interesting for application because they fulfil a range of criteria typically sought for in biocatalysis: besides their ability to catalyse a synthetically useful reaction, some natural homologs were found to have a very large substrate scope (i.e. their reactivity was not restricted to a single compound, as often assumed in enzyme catalysis), they can be easily produced on a large scale, and because the three-dimensional structure of many BVMOs has been determined, enzyme engineering could be applied to produce variants with improved thermostability and/or reactivity. Another advantage of using enzymes for the reaction is their frequently observed regio- and enantioselectivity, owed to the steric control of substrate orientation during catalysis within the enzyme’s active site.
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Hippocampal lesioning led to a considerable loss of cells in pyramidal cells (CA1-CA3) as well as granule cells in the dentate gyrus. Ibotenic acid lesioning also causes some damage to axons along the perforant pathway. Typically when lesioning is done with other chemicals the subject can not relearn a task. However, due to Ibotenic acid's reactivity with glutamate receptors such as the NMDA receptor, Ibotenic acid lesioning does allow the subject to relearn tasks.
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For instance, ureas are less acidic than thioureas by roughly 6 pKa units, but it is not generally true that ureas are significantly worse are catalyzing reactions. Furthermore, the effect of varying substituents on the catalyst is rarely well understood. Small substituent changes can completely change reactivity or selectivity. An example of this was in the optimization studies of a bifunctional Strecker reaction catalyst, one of the first well-studied thiourea catalysts.
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The author noted that a child under prolonged stress "may develop complex patterns of protective responses that can include hyperarousal—hypervigilance, agitation, flashbacks and emotional reactivity, or hypoarousal—dissociative responses, emotional numbing (self-harm may be used as a tool to 'feel alive'), passive compliance and poor access to cognitive functioning". The study's findings also suggested that enforcement of immigration laws poses "serious health challenges and risks for lifelong mental illness in children".
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Since the BAS promotes the individual to pursue actions that may result in reward, BAS sensitivity is involved in the initiation of addiction. Significant associations have been found between high BAS such as alcohol misuse in school girls, hazardous drinking in men, illicit drug abuse, and tobacco use. BAS sensitivity is a significant predictor of reactivity to substance cues, or cravings. Conversely, BIS sensitivity is involved in avoiding negative situations or affect (such as withdrawal).
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Hardiness appears to be related to differences in physiological arousal. It is believed that hardiness helps decrease the ability of stressful events to produce arousal in the sympathetic nervous system. Some support for this notion can be found in studies demonstrating that participants that score high on hardiness exhibit lower cardiovascular reactivity in response to stress. Another study examined the functional efficacy of immune cells in participants scoring low and high on hardiness.
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The capsules (often made of wax) around the monomer and the catalyst are important to maintain separation until the crack facilitates the reaction. In the capsule-catalyst system, the encapsulated healing agent is released into the polymer matrix and reacts with the catalyst, already present in the matrix. There are many challenges in designing this type of material. First, the reactivity of the catalyst must be maintained even after it is enclosed in wax.
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In PWRs reactor power can be viewed as following steam (turbine) demand due to the reactivity feedback of the temperature change caused by increased or decreased steam flow. (See: Negative temperature coefficient.) Boron and cadmium control rods are used to maintain primary system temperature at the desired point. In order to decrease power, the operator throttles shut turbine inlet valves. This would result in less steam being drawn from the steam generators.
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Chen, Hsuan-Ying; Tang, Hui-Yi; Lin, Chu-Chieh "Ring-Opening Polymerization of Lactides Initiated by Zinc Alkoxides Derived from NNO-Tridentate Ligands" Macromolecules 2006, volume 39, pp. 3745-3752. Tshuva, Edit Y.; Goldberg, Israel; Kol, Moshe; Goldschmidt, Zeev "Zirconium Complexes of Amine- Bis(phenolate) Ligands as Catalysts for 1-Hexene Polymerization: Peripheral Structural Parameters Strongly Affect Reactivity" Organometallics 2001, volume 20, pp. 3017-3028. It is a precursor to the drug chloropyramine.
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Barry M. Trost (born June 13, 1941 in Philadelphia) is an American chemist, Tamaki Professor of Humanities and Sciences at Stanford University. He studied at the University of Pennsylvania and obtained his B.A. in 1962. His Ph.D. thesis research on The Structure and Reactivity of Enolate Anions was conducted at the Massachusetts Institute of Technology. He was professor at the University of Wisconsin–Madison from 1965 until his appointment to Stanford University in 1987.
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