Once it oxidizes, it's more or less useless to human health.
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When this biosensor comes into contact with glucose, the enzyme oxidizes the blood sugar.
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Heating fats and oils during cooking oxidizes them, generating free radicals which seep into our foods.
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The juice also oxidizes relatively fast, due to the fact that the motor sucks in a lot of air.
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There, the sulfur oxidizes into sulfate aerosols that reflect sunlight back to space, reducing evaporation on the planet's surface.
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Coal oxidizes in air, so its heat content and quality begin to deteriorate as soon as coal is mined.
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As bolder red wine oxidizes, tannins soften and become less harsh, making for a rounder, more balanced overall drinking experience.
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This is my theory too — it is mostly the alcohol in the wine that oxidizes when a bottle is open and old.
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The pit is made from durable cast iron that will take on a unique, ruddy finish as it oxidizes over the years.
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The sebum becomes black in color because when it touches the air, it oxidizes, Papri Sarkar, a dermatologist in Massachusetts, previously told Insider.
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When we breathe in, oxygen breaks down (or oxidizes) chemical bonds in calories, for example, and releases the energy for use by our cells.
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The difference with this new launch is that the ultraviolet-colored formula oxidizes on your face (instead of hardening) before you rinse it off.
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In 1964, Pepper was among the first sculptors to use the industrial alloy, which oxidizes and stabilizes without the use of paint or sealant.
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Ozone oxidizes those lipids, Dr. Valacchi said, causing inflammation, breaking down the barrier function of the skin and activating a cascade of DNA-damaging events.
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"Maintenance can be as little as a gloss or once a year — or as much as every three months, depending on how your hair oxidizes," Brown says.
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"When vitamin C is exposed to air, it oxidizes and changes its form into something that isn't as effective, and it doesn't work as well on your skin," he explains.
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After three or four months, your yellow-green complexion has turned brownish-black because your blood vessels have deteriorated to the point that the iron inside them spills out, becoming brownish-black as it oxidizes.
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A quick science lesson here: When you use a bleaching agent, it oxidizes the melanin in your hair to make it lighter, and just like oxidation isn't good for your skin, it's not great for your hair, either.
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The bleach oxidizes the lycopene, thus allowing the now-polarized metabolite to dissolve.
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Niobium chloride rapidly oxidizes and hydrolyzes in air to form niobium(V) oxide.
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The redox reaction involved where mercury oxidizes the copper is: :Hg2+ \+ Cu → Hg + Cu2+.
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Ni(Ph2N2)(PPh3)2 is well characterized. It oxidizes to give azoxybenzene. Hydrogenation gives diphenylhydrazine.
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The process of nitrification oxidizes ammonium (from the wastewater) to nitrite (), and then nitrite is oxidized to nitrate ().
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It is unaffected by ordinary solvents, dilute acids, or fused alkalis. However, chromic acid oxidizes it to carbon dioxide.
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Nitrifying bacteria are chemolithotrophic organisms that include species of the genera Nitrosomonas, Nitrosococcus, Nitrobacter and Nitrococcus. These bacteria get their energy by the oxidation of inorganic nitrogen compounds. Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). Many species of nitrifying bacteria have complex internal membrane systems that are the location for key enzymes in nitrification: ammonia monooxygenase (which oxidizes ammonia to hydroxylamine), hydroxylamine oxidoreductase (which oxidizes hydroxylamine to nitric oxide - which is oxidized to nitrite by a currently unidentified enzyme), and nitrite oxidoreductase (which oxidizes nitrite to nitrate).
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The dihydrolipoate, still bound to a lysine residue of the complex, then migrates to the dihydrolipoyl dehydrogenase (E3) active site where it undergoes a flavin-mediated oxidation, identical in chemistry to disulfide isomerase. First, FAD oxidizes dihydrolipoate back to its lipoate resting state, producing FADH2. Then, a NAD+ cofactor oxidizes FADH2 back to its FAD resting state, producing NADH.
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Vol 136. No. not available. p. 1-10. A subgroup of methylotrophs, the methanotrophs, oxidizes roughly %80-90 of the global methane.
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Sulfating roasting oxidizes certain sulfide ores to sulfates in a controlled supply of air to enable leaching of the sulfate for further processing.
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Reaction with non-metallic elements, with the exceptions of nitrogen, oxygen, noble gases, silicon, and halogens other than iodine, usually oxidizes them to their highest oxidation states as acids with the formation of nitrogen dioxide for concentrated acid and nitric oxide for dilute acid. :Cgraphite \+ 4 HNO3 → CO2 \+ 4 NO2 \+ 2 H2O or :3 Cgraphite \+ 4 HNO3 → 3 CO2 \+ 4 NO + 2 H2O Concentrated nitric acid oxidizes I2, P4, and S8 into HIO3, H3PO4, and H2SO4, respectively. Although it reacts with graphite and amorphous carbon, it does not react with diamond; it can separate diamond from the graphite that it oxidizes.
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Figure 4: The proteins that allosterically regulate tTG. On the left Erp57 which oxidizes tTG and on the right TRX-1 which reduces tTG.
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A dehydrogenase (also called DH or DHase in the literature) is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. They also catalyze the reverse reaction, for instance alcohol dehydrogenase not only oxidizes ethanol to acetaldehyde in animals but also produces ethanol from acetaldehyde in yeast.
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Disulfide bond formation protein B (DsbB) is a protein component of the pathway that leads to disulfide bond formation in periplasmic proteins of Escherichia coli () and other bacteria. In Bacillus subtilis it is known as BdbC (). The DsbB protein oxidizes the periplasmic protein DsbA which in turn oxidizes cysteines in other periplasmic proteins in order to make disulfide bonds. DsbB acts as a redox potential transducer across the cytoplasmic membrane.
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Encoded by the gene gldA, the enzyme glycerol dehydrogenase, GlyDH catalyzes the oxidation of glycerol to glycerone. Unlike more common pathways utilizing glycerol, GlyDH effectively oxidizes glycerol in anaerobic metabolic pathways under ATP-independent conditions (a useful mechanism in the breakdown of glycerol in bacteria). In addition, GlyDH selectively oxidizes the C2 hydroxyl group to form a ketone rather than a terminal hydroxyl group to form an aldehyde.
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Arachidonic acid bound to the PTGS2 (COX-2) enzyme. polar interactions between Archidonic Acid (cyan) and Ser-530 and Tyr-385 residues are shown with yellow dashed lines. The substrate is stabilized by hydrophobic interactions. Mechanism of COX activation and catalysis. A hydroperoxide oxidizes the heme to a ferryl-oxo derivative that either is reduced in the first step of the peroxidase cycle or oxidizes Tyrosine 385 to a tyrosyl radical.
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Thomas Clausen et al. "Hair Preparations" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. In these applications, the nearly colourless dye precursor oxidizes to the dye.
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Boy Cornils, Richard W. Fischer, Christian Kohlpaintner "Butanals" in Ullmann's Encyclopedia of Industrial Chemistry, 2000, Wiley-VCH, Weinheim. . Upon prolonged exposure to air, butyraldehyde oxidizes to form butyric acid.
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First, the random orientation of the crystal grains makes it difficult to choose a value for the linear rate constant. Second, oxidant molecules diffuse rapidly along grain boundaries, so that poly-silicon oxidizes more rapidly than single-crystal silicon. Dopant atoms strain the silicon lattice, and make it easier for silicon atoms to bond with incoming oxygen. This effect may be neglected in many cases, but heavily doped silicon oxidizes significantly faster.
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This design ensured that the oxygen needed in the reactions was absorbed when it was in excess and released when it was needed, allowing all three pollutants to be removed in a single catalytic component. The three-way catalytic converter reduces nitrogen oxides to nitrogen and oxygen, oxidizes carbon monoxide to carbon dioxide and oxidizes unburnt hydrocarbons to carbon dioxide and water.An AIChE Mini History of John Mooney , New Jersey Institute of Technology. Accessed November 15, 2008.
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Sulfones are typically prepared by organic oxidation of thioethers, often referred to as sulfides. Sulfoxides are intermediates in this route. For example, dimethyl sulfide oxidizes to dimethyl sulfoxide and then to dimethyl sulfone.
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Elevated levels of homocysteine have also been linked to increased fractures in elderly persons. Homocysteine auto-oxidizes and reacts with reactive oxygen intermediates, damaging endothelial cells and increasing the risk of thrombus formation.
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In one variation the mechanism is thought to be the following: The dichromate oxidizes the mercury, forming a layer of mercury oxide. In the process the dichromate is reduced to the chromium(III) ion. The oxidized layer on the mercury reduces the surface tension of the blob and the blob flattens out coming in contact with the iron nail. Then the mercury sulfate oxidizes the iron to the iron(II) ion, and in the process is reduced back to metallic mercury.
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Next the oxidation catalyst oxidizes the hydrocarbons and carbon monoxide to form carbon dioxide and water.Catalytic Converter at Wikipedia.org Platinum is used in both the reduction and the oxidation catalysts.How Catalytic Converters Work at howstuffworks.
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L-2-hydroxyglutarate is produced by promiscuous action of malate dehydrogenase on 2-oxoglutarate, and L-2-hydroxyglutarate dehydrogenase is an example of a metabolite repair enzyme that oxidizes L-2-hydroxyglutarate back to 2-oxoglutarate.
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Cobalt(II) hydride is an inorganic compound with a chemical formula CoH2. It has dark grey crystals. It oxidizes slowly in air and reacts with water. Two forms of cobalt(II) hydride exist under high pressure.
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Polyunsaturated fatty acids in culinary oils undergo oxidative deterioration at temperatures of . The heating causes a free radical chain reaction, which oxidizes the PUFAs into hydroperoxide, which further decomposes into a complex mixture of secondary products.
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For instance, ulvospinel in igneous rocks such as basalt and gabbro commonly oxidizes during subsolidus cooling to produce regular intergrowths of magnetite and ilmenite. The process can determine what magnetic record is inherited by the rock.
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C-5 sterol desaturase (also known as sterol C-5 desaturase and C5SD) is an enzyme that is highly conserved among eukaryotes and catalyzes the dehydrogenation of a C-5(6) bond in a sterol intermediate compound as a step in the biosynthesis of major sterols. The precise structure of the enzyme’s substrate varies by species. For example, the human C-5 sterol desaturase (also known as lathosterol oxidase) oxidizes lathosterol, while its ortholog ERG3 in the yeast Saccharomyces cerevisiae oxidizes episterol. The precise structural details of C-5 sterol desaturase substrates vary across eukaryotes.
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Indoxyl-2-carboxylic acid is generated. This material readily decarboxylates to give indoxyl, which oxidizes in air to form indigo. The preparation of indigo dye is practiced in college laboratory classes according to the original Baeyer-Drewsen route.
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An oxygenase is any enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air) to it. The oxygenases form a class of oxidoreductases; their EC number is EC 1.13 or EC 1.14.
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Uracil dehydrogenase (, uracil oxidase) is an enzyme with systematic name uracil:(acceptor) oxidoreductase. This enzyme catalyses the following chemical reaction : uracil + acceptor \rightleftharpoons barbiturate + reduced acceptor Also oxidizes thymine. The enzyme acts on the hydrated derivative of the substrate.
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Martin et al. 2003 Nat. Biotechnol. 21:796Ro et al. 2006 Nature 440:940 These enzymes included the cytochrome P450 that oxidizes amorphadiene to artemisinic acid and the redox partners that transfer reducing equivalents from the enzyme to cofactors.
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The tetrahydrate can be prepared by dissolving iron in warm hydrated hydrofluoric acid and precipitating the result by addition of ethanol. It oxidizes in moist air to give, inter alia, a hydrate of iron(III) fluoride, (FeF3)2·9H2O.
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Building stone containing pyrite tends to stain brown as pyrite oxidizes. This problem appears to be significantly worse if any marcasite is present.Bowles, Oliver (1918) The Structural and Ornamental Stones of Minnesota. Bulletin 663, United States Geological Survey, Washington. p. 25.
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Spermine oxidase (, PAOh1/SMO, AtPAO1, AtPAO4, SMO) is an enzyme with systematic name spermidine:oxygen oxidoreductase (spermidine-forming). This enzyme catalyses the following chemical reaction : spermine + O2 \+ H2O \rightleftharpoons spermidine + 3-aminopropanal + H2O2 The enzyme from Arabidopsis thaliana oxidizes norspermine to norspermidine.
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Potassium permanganate and sulfuric acid react to produce some ozone, which has a high oxidizing power and rapidly oxidizes the alcohol, causing it to combust. As the reaction also produces explosive Mn2O7, this should only be attempted with great care.
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Cyclic alcohol dehydrogenase (quinone) (, cyclic alcohol dehydrogenase, MCAD) is an enzyme with systematic name cyclic alcohol:quinone oxidoreductase. This enzyme catalyses the following chemical reaction : cyclic alcohol + quinone \rightleftharpoons cyclic ketone + quinol This enzyme oxidizes a wide variety of cyclic alcohols.
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Hemp oil oxidizes and turns rancid within a short period of time if not stored properly; its shelf life is extended when it is stored in a dark airtight container and refrigerated. Both light and heat can degrade hemp oil.
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CES1 oxidizes the tertiary amide carbonyl carbons of edoxabans to carboxylic acid groups. CYP3A4 and CYP3A5 oxidize edoxabans via hydroxylation or demethylation. In hydrolysis, 2-amino-5-chloropyridine moiety of edoxaban is removed. Glucuronidation occurs to a lesser extend via glucuronosyltransferases.
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Ytterbium metal tarnishes slowly in air. Finely dispersed ytterbium readily oxidizes in air and under oxygen. Mixtures of powdered ytterbium with polytetrafluoroethylene or hexachloroethane burn with a luminous emerald-green flame. Ytterbium reacts with hydrogen to form various non-stoichiometric hydrides.
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Filamentous carbon structures typically range between 10 and 500 nanometers in diameter. They are typically 10,000 nanometers (10 micrometers) long. They have a duplex structure. The outside of the structures is difficult to oxidize, but the core oxidizes more easily.
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In 1885, he began work at the University of Strasbourg under the renowned botanist Anton de Bary; Winogradsky became renowned for his work on sulfur bacteria. In 1888, he relocated to Zurich, where he began investigation into the process of nitrification, identifying the genera Nitrosomonas and Nitrosococcus, which oxidizes ammonium to nitrite, and Nitrobacter, which oxidizes nitrite to nitrate. He returned to St. Petersburg for the period 1891–1905, and headed the division of general microbiology of the Institute of Experimental Medicine. During this period, he identified the obligate anaerobe Clostridium pasteurianum, which is capable of fixing atmospheric nitrogen.
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Phylloquinone A1 is the next early electron acceptor in PSI. Phylloquinone is also sometimes called vitamin K1. Phylloquinone A1 oxidizes a0 in order to receive the electron and in turn reduces Fx in order to pass the electron to Fb and Fa.
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Diphenylphosphine readily oxidizes. :Ph2PH + O2 → Ph2P(O)OH An intermediate in this oxidation is diphenylphosphine oxide. The use of the diphenylphosphine–borane complex, Ph2PH•BH3 avoids the problem of phosphine oxidation by protecting the phosphine from oxidation and is available through chemical vendors.
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Sodium bisulfite has low toxicity, 130 mg/kg (mice, intravenous). According to another source, the acceptable daily intake is up to 0.7 milligrams per kilogram of body weight. Sodium metabisulfite oxidizes in the liver to harmless sulfate which is excreted in the urine.
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Agaritine oxidizes rapidly upon storage, however, and is totally degraded after 48 hours in aqueous solution with exposure to air. It has also been shown to decompose readily upon cooking (up to 90% reduction) as well as upon freezing (up to 75% reduction).
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Accidentally, this enzyme also oxidizes, at no additional cost for M. vaccae, cyclohexane into cyclohexanol. Thus, cyclohexane is co-metabolized in the presence of propane. This allows for the commensal growth of Pseudomonas on cyclohexane. The latter can metabolize cyclohexanol, but not cyclohexane.
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During combustion, vanadium oxidizes and reacts with sodium and sulfur, yielding vanadate compounds with melting points as low as 530 °C, which attack the passivation layer on steel and render it susceptible to corrosion. The solid vanadium compounds also abrade engine components.
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Air oxidation is responsible its formation, and oxidizes faster to a similar pulvinic acid type pigment oxidized variant, variegatorubin.Gill, M., and Steglich, W. (1987) Pigments of fungi (Macromycetes). Prog Chem Org Nat Prod 51: 1–317.Edwards and Gill (1973) Constituents of the Higher Fungi.
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Cytochrome P450 1A2 oxidizes 4-aminobiphenyl to N-hydroxy-4-aminobiphenyl. Following O-acetylation, the latter can form DNA adducts. O-Acetylation reactions are catalyzed by NAT, N-acetyltransferase; and UDP-glucuronosyltransferase (UGT) enzymes. Two different enzymes can catalyze this reaction, NAT1 and NAT2.
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Among its many transformations, it oxidizes methoxyl phenols to quinone acetals, alkenes to acetals, and cyclic alkenes to ring-contracted aldehydes.Mukund P. Sibi, Luiz F. Silva Jr., Vânia M. T. Carneiro "Thallium(III) Nitrate Trihydrate" Encyclopedia of Reagents for Organic Synthesis 2008 John Wiley & Sons.
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Arils are white and the size of a grape, each containing a 15 × 8 mm seed. Once opened, the fruit should be consumed quickly (in a few hours), as it loses flavour rapidly and fruit oxidizes. The seeds are also edible after boiling or roasting.
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One way of understanding the carcinogenic effects of benzene is by examining the products of biological oxidation. Pure benzene, for example, oxidizes in the body to produce an epoxide, benzene oxide, which is not excreted readily and can interact with DNA to produce harmful mutations.
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Testosterone 17beta-dehydrogenase (NADP+) (, 17-ketoreductase, NADP-dependent testosterone-17beta-oxidoreductase, testosterone 17beta-dehydrogenase (NADP)) is an enzyme with systematic name 17beta-hydroxysteroid:NADP+ 17-oxidoreductase. This enzyme catalyses the following chemical reaction : testosterone + NADP+ \rightleftharpoons androstenedione + NADPH + H+ Also oxidizes 3-hydroxyhexobarbital to 3-oxohexobarbital.
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It also oxidizes in strong oxidizing agents like concentrated nitric acid. In molten metals, it dissolves and forms metal carbides. Carbon fibers do not differ from carbon in their corrosion behavior. ;Silicon carbide Pure silicon carbide is one of the most corrosion-resistant materials.
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Chloramine-T is a strong oxidant. It oxidizes hydrogen sulfide to sulfur and mustard gas to yield a harmless crystalline sulfimide. It converts iodide to iodine monochloride (ICl). ICl rapidly undergoes electrophilic substitution predominantly with activated aromatic rings, such as those of the amino acid tyrosine.
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Abbett, p.19-28 Where nearby water bodies can rapidly dilute this liquid waste, primary treated sewage may be discharged so natural biological decomposition oxidizes remaining waste.Abbett, p.19-20 The city of San Diego used Pacific Ocean dilution of primary treated effluent into the 21st century.
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SdhA provides the binding site for the oxidation of succinate. The side chains Thr254, His354, and Arg399 of subunit A stabilize the molecule while FAD oxidizes and carries the electrons to the first of the iron-sulfur clusters, [2Fe-2S]. This can be seen in image 5.
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The oxidizing agent in either case oxidizes and destroys the dyes formed from the tannins of the wood and accentuated (reinforced) by sulfides present in it. Steam exploded fibre is a pulping and extraction technique that has been applied to wood and other fibrous organic material.
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This oxide is used in silver- oxide batteries. In organic chemistry, silver oxide is used as a mild oxidizing agent. For example, it oxidizes aldehydes to carboxylic acids. Such reactions often work best when the silver oxide is prepared in situ from silver nitrate and alkali hydroxide.
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Diphenylcarbazide is a white solid that is scarcely soluble in water, but readily soluble in organic solvents like acetone, hot ethanol and acetic acid. It forms colored complex compounds with certain metal ions. Diphenylcarbazide oxidizes to Diphenylcarbazone when exposed to light and air, turning pink in the process.
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Powdered eggs have a storage life of 5 to 10 years when stored without oxygen in a cool storage environment. The process of drying eggs so as to make powdered eggs oxidizes the cholesterol, which has been shown to be helpful at reducing aortic atherosclerosis in animal trials.
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Their solution to addressing the variations in air / fuel mixtures was to combine rare-earth oxides and base metal oxide components in the catalyst together with Platinum and Rhodium in a ceramic honeycomb with tiny passages coated with the catalytic material. This design ensured that the oxygen needed in the reactions was absorbed up when it was in excess and released when it was needed, allowing all three pollutants to be removed in a single catalytic component. The three-way catalytic converter reduces nitrogen oxides to nitrogen and oxygen, oxidizes carbon monoxide to carbon dioxide and oxidizes unburnt hydrocarbons to carbon dioxide and water.An AIChE Mini History of John Mooney , New Jersey Institute of Technology.
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Wrought iron is shaped by repeated blows with a hammer while hot. A piece of hot short iron will crack if worked with a hammer. When a piece of hot iron or steel cracks the exposed surface immediately oxidizes. This layer of oxide prevents the mending of the crack by welding.
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Archiv für mikroskopische Anatomie 55:558-575(Also Tafel XXXII) The indicator Janus Green B changes colour according to the amount of oxygen present. When oxygen is present, the indicator oxidizes to a blue colour. In the absence of oxygen, the indicator is reduced and changes to a pink colour.
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The two copper atoms within the active site of tyrosinase enzymes interact with dioxygen to form a highly reactive chemical intermediate that then oxidizes the substrate. The activity of tyrosinase is similar to catechol oxidase, a related class of copper oxidase. Tyrosinases and catechol oxidases are collectively termed polyphenol oxidases.
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Coffee ground vomitus refers to a particular appearance of vomit. Within organic heme molecules of red blood cells is the element iron, which oxidizes following exposure to gastric acid. This reaction causes the vomitus to look like ground coffee. Coffee ground vomitus is a sign of possible upper gastrointestinal bleeding.
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Several oxides of cobalt are known. Green cobalt(II) oxide (CoO) has rocksalt structure. It is readily oxidized with water and oxygen to brown cobalt(III) hydroxide (Co(OH)3). At temperatures of 600–700 °C, CoO oxidizes to the blue cobalt(II,III) oxide (Co3O4), which has a spinel structure.
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Potassium permanganate in neutral solution oxidizes it to nitrobenzene; in alkaline solution to azobenzene, ammonia, and oxalic acid; in acid solution to aniline black. Hypochlorous acid gives 4-aminophenol and para-amino diphenylamine. Oxidation with persulfate affords a variety of polyanilines. These polymers exhibit rich redox and acid-base properties.
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Unlike ground state oxygen, singlet oxygen participates in Diels–Alder [4+2]- and [2+2]-cycloaddition reactions and formal concerted ene reactions. It oxidizes thioethers to sulfoxides. Organometallic complexes are often degraded by singlet oxygen. With some substrates 1,2-dioxetanes are formed; cyclic dienes such as 1,3-cyclohexadiene form [4+2] cycloaddition adducts.
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DpgA condenses acetyl-CoA and malonyl-CoA into a polyketide and then cyclizes the polyketide into a C8 intermediate. DHPG synthesis involving enzymes DpgB and DpgD. Aromatization of the C8 intermediate through dehydration and then alkene isomerization. DpgC oxidizes the aromatic intermediate at the benzylic carbon using oxygen to an alpha-keto compound.
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Formate dehydrogenase (acceptor) (, FDHH, FDH-H, FDH-O, formate dehydrogenase H, formate dehydrogenase O) is an enzyme with systematic name formate:acceptor oxidoreductase. This enzyme catalyses the following chemical reaction : formate + acceptor \rightleftharpoons CO2 \+ reduced acceptor Formate dehydrogenase H is a cytoplasmic enzyme that oxidizes formate without oxygen transfer] transferring electrons to a hydrogenase.
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MPS is a versatile oxidant. It oxidizes aldehydes to carboxylic acids; in the presence of alcoholic solvents, the esters may be obtained. Internal alkenes may be cleaved to two carboxylic acids (see below), while terminal alkenes may be epoxidized. Sulfides give sulfones, tertiary amines give amine oxides, and phosphines give phosphine oxides.
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Scrubbing with limestone follows the following idealized reaction: : SO2 \+ CaCO3 → CaSO3 \+ CO2 Scrubbing with hydrated lime follows the following idealized reaction: : SO2 \+ Ca(OH)2 → CaSO3 \+ H2O The resulting calcium sulfite oxidizes in air to give gypsum: : O2 \+ 2 CaSO3 → 2 CaSO4 The gypsum, if sufficiently pure, is marketable as a building material.
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Figure 1. Hypothesized hydride transfer reaction mechanism catalyzed by homoserine dehydrogenase and NAD(P)H. PBD ). Homoserine dehydrogenase catalyzes the reaction of aspartate-semialdehyde (ASA) to homoserine. The overall reaction reduces the C4 carboxylic acid functional group of ASA to a primary alcohol and oxidizes the C1 aldehyde to a carboxylic acid.
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RuO4 is of specialized value in organic chemistry because it oxidizes virtually any hydrocarbon. For example, it will oxidize adamantane to 1-adamantanol. Because it is such an aggressive oxidant, reaction conditions must be mild, generally room temperature. Although a strong oxidant, RuO4 oxidations do not perturb stereocenters that are not oxidized.
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Terbium metal is an electropositive element and oxidizes in the presence of most acids (such as sulfuric acid), all of the halogens, and even water. :2 Tb (s) + 3 H2SO4 → 2 Tb3+ \+ 3 \+ 3 H2↑ :2 Tb + 3 X2 → 2 TbX3 (X = F, Cl, Br, I) :2 Tb (s) + 6 H2O → 2 Tb(OH)3 \+ 3 H2↑ Terbium also oxidizes readily in air to form a mixed terbium(III,IV) oxide: :8 Tb + 7 O2 → 2 Tb4O7 The most common oxidation state of terbium is +3 (trivalent), such as . In the solid state, tetravalent terbium is also known, in compounds such as TbO2 and TbF4. In solution, terbium typically forms trivalent species, but can be oxidized to the tetravalent state with ozone in highly basic aqueous conditions.
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Electrolytically refined manganese chips and a 1 cm3 cube Manganese is a silvery-gray metal that resembles iron. It is hard and very brittle, difficult to fuse, but easy to oxidize. Manganese metal and its common ions are paramagnetic. Manganese tarnishes slowly in air and oxidizes ("rusts") like iron in water containing dissolved oxygen.
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Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in structure. Being a form of carbon, diamond oxidizes in air if heated over 700 °C. In absence of oxygen, e.g. in a flow of high-purity argon gas, diamond can be heated up to about 1700 °C.
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However, metallic calcium is highly unstable in air and oxidizes rapidly. Measurements had to be made within a glovebox under an inert environment to prevent device breakdown. This limited practical application of the devices. Cola and his team later solved the challenges with device instability by modifying the diode structure with multiple layers of oxide.
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Aldehyde oxidase is very concentrated in the liver, where it oxidizes multiple aldehydes and nitrogenous heterocyclic compounds, such as anti-cancer and immunosuppressive drugs. Some AO activity has been located in other parts of the body—including the lungs (epithelial cells and alveolar cells), the kidneys, and the gastrointestinal tract (small and large intestines).
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Episode 305 of How It's Made, filmed at verrerie-walker.com in Anjou, Quebec, Canada Silver would be ideal for telescope mirrors and other demanding optical applications, since it has the best initial front-surface reflectivity in the visible spectrum. However, it quickly oxidizes and absorbs atmospheric sulfur to create a dark, low- reflectivity tarnish.
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9,10-Anthraquinone is used as a digester additive in production of paper pulp by alkaline processes, like the Kraft, the alkaline sulfite or the Soda-AQ processes. The anthraquinone is a redox catalyst. The reaction mechanism may involve single electron transfer (SET). The anthraquinone oxidizes the reducing end of polysaccharides in the pulp, i.e.
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The acid reacts as a typical carboxylic acid: it can form amide, ester, anhydride, and chloride derivatives. Its acid chloride is commonly used as the intermediate to obtain the others. When heated with a chromic acid solution it is oxidized to acetone. Alkaline potassium permanganate oxidizes it to α-hydroxyisobutyric acid, (CH3)2C(OH)-CO2H.
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The formyl group readily oxidizes to the corresponding carboxyl group (−COOH). The preferred oxidant in industry is oxygen or air. In the laboratory, popular oxidizing agents include potassium permanganate, nitric acid, chromium(VI) oxide, and chromic acid. The combination of manganese dioxide, cyanide, acetic acid and methanol will convert the aldehyde to a methyl ester.
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The anemia caused by copper deficiency is thought to be caused by impaired iron transport. Hephaestin is a copper containing ferroxidase enzyme located in the duodenal muscosa that oxidizes iron and facilitates its transfer across the basolateral membrane into circulation. Another iron transporting enzyme is ceruloplasmin. This enzyme is required to mobilize iron from the reticuloendothelial cell to plasma.
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However, it is heavy, which is a challenge, but appreciated on windy days. It needs much care, though, and can easily rust and corrode if not waterproofed. Aluminum is more common than steel furniture, mostly because it does not rust, although it oxidizes, turning into a chalky white. It is also lighter than steel, making it more desirable.
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Clean-in-place systems are typically used to remove fouling from membranes after extensive use. The CIP process may use detergents, reactive agents such as sodium hypochlorite and acids and alkalis such as citric acid and sodium hydroxide (NaOH). Sodium hypochlorite (bleach) must be removed from the feed in some membrane plants. Bleach oxidizes thin-film membranes.
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The liquid can be applied with a variety of tools, such as a small blunt knife (mmanwauli), slivers of wood, or metal combs. The dye then oxidizes, staining the skin an indigo color that lasts for approximately 8 days. After the staining process is complete, the skin is rubbed with oil in order to create a distinctive sheen.
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Arsenic pentasulfide hydrolyzes in boiling water, giving arsenous acid and sulfur: : As2S5 \+ 6 H2O → 2 H3AsO3 \+ 2 S + 3 H2S It oxidizes in air at elevated temperatures producing arsenic oxides, the products and yields of which are variable. In alkali metal sulfide solutions arsenic pentasulfide forms a thioarsenate anion, [AsS4]3−, which contain As(V) centres.
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It is incompatible with ketones and primary alcohols, as it oxidizes them to aldehydes and carboxylic acids while being itself reduced to Cr3+. Therefore, CrO5 is a good oxidizing agent, even better than chromates and dichromates due to the presence of two reactive peroxo ligands, but due to its low stability it is not used in organic syntheses.
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Iron(III) chloride in ether solution oxidizes methyl lithium to give first light greenish yellow lithium tetrachloroferrate(III) solution and then, with further addition of methyl lithium, lithium tetrachloroferrate(II) : :2 FeCl3 + LiCH3 -> FeCl2 + LiFeCl4 + .CH3 :LiFeCl4 + LiCH3 -> Li2FeCl4 + .CH3 The methyl radicals combine with themselves or react with other components to give mostly ethane and some methane .
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Like many yeasts, Candida blankii has been the subject of various biotechnological studies, including for use as a BOD biosensor. The metabolic process of C. blankii is aerobic. Consequently, it oxidizes many forms of alcohol, amino acid, carbohydrates, and other organic compounds. As a BOD biosensor, practical applications may be limited due to short term effectiveness.
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Reduction and oxidation of mercury mostly occur closer to the ocean water surface. These are either driven by sunlight or by microbial activity. Under UV radiation, elemental mercury oxidizes and dissolves directly in ocean water or binds to other particles. The reverse reaction reduces some mercury Hg2+ to elemental mercury Hg(0) and returns to the atmosphere.
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After a photoresist is no longer needed, it must be removed from the substrate. This usually requires a liquid "resist stripper", which chemically alters the resist so that it no longer adheres to the substrate. Alternatively, photoresist may be removed by a plasma containing oxygen, which oxidizes it. This process is called ashing, and resembles dry etching.
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If it does come in contact with water, though, it will combine with the atoms of both oxygen and hydrogen to form strontium hydroxide and pure hydrogen gas which quickly diffuses in the air. In addition, strontium, like rubidium, oxidizes in air and turns a yellow color. When ignited, it will burn with a strong red flame.
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However, u'amea in Sāmoan is also an archaic word for a type of lava (known in Hawai'i as ʻaʻā), from u'a ("viscous, glutinous") and mea ("red-brown," as in the color of the manumea, the "reddish-brown bird"). U'a was used in colonial times to refer to iron because it turns the same color ("mea") as it oxidizes.
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The amount of ascorbic acid can be calculated by Faraday's law. Another alternative uses N-bromosuccinimide (NBS) as the oxidizing agent, in the presence of potassium iodide and starch. The NBS first oxidizes the ascorbic acid; when the latter is exhausted, the NBS liberates the iodine from the potassium iodide, which then forms the blue-black complex with starch.
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Limonene is a relatively stable monoterpene and can be distilled without decomposition, although at elevated temperatures it cracks to form isoprene. It oxidizes easily in moist air to produce carveol, carvone, and limonene oxide. With sulfur, it undergoes dehydrogenation to p-cymene. Limonene occurs commonly as the D\- or (R)-enantiomer, but racemizes to dipentene at 300 °C.
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Dilute solutions containing iodine- starch complex. Using starch as an indicator can help create a sharper color change at the endpoint (Dark blue→Colorless). The color above can be seen just before the endpoint is reached. To a known volume of sample, an excess but known amount of iodide is added, which the oxidizing agent then oxidizes to iodine.
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This enzyme is termed "phagocyte NADPH oxidase" (PHOX). This enzyme oxidizes NADPH and reduces molecular oxygen to produce superoxide anions, a reactive oxygen species. Superoxide is then disproportionated into peroxide and molecular oxygen by superoxide dismutase. Finally, peroxide is used by myeloperoxidase to oxidize chloride ions into hypochlorite (the active component of bleach), which is toxic to bacteria.
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Excessive doses of choline can have adverse effects. Daily 8–20 g doses of choline, for example, have been found to cause low blood pressure, nausea, diarrhea and fish-like body odor. The odor is due to trimethylamine (TMA) formed by the gut microbes from the unabsorbed choline (see trimethylaminuria). The liver oxidizes TMA to trimethylamine N-oxide (TMAO).
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Some of the carbon is oxidised into carbon monoxide, CO, and carbon dioxide, CO2. This also oxidizes impurities in the pig iron. The container is rotated and the processed pig iron can be separated from the oxidised impurities. Before the mid 19th century, pig iron from the blast furnace was made into wrought iron, which is commercially pure iron.
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The Sarett oxidation is an organic reaction that oxidizes primary and secondary alcohols to aldehydes and ketones, respectively, using chromium trioxide and pyridine. Unlike the similar Jones oxidation, the Sarett oxidation will not further oxidize primary alcohols to their carboxylic acid form, neither will it affect carbon-carbon double bonds.Margareta Avram (1983). "Chimie organica" p. 472.
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Glycogen is broken down rapidly via glycogen phosphorylase into individual glucose units during intense exercise. Glucose is then oxidized to pyruvate and under anaerobic conditions is reduced to lactic acid. This reaction oxidizes NADH to NAD, thereby releasing a hydrogen ion, promoting acidosis. For this reason, fast glycolysis can not be sustained for long periods of time.
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The name "mixed-function oxidase" indicates that the enzyme oxidizes two different substrate simultaneously. Desaturation of fatty acyl-CoA in vertebrates is an example of the mixed-function oxidase reaction. In the process, saturated fatty acyl-CoA and NADPH are oxidized by molecular oxygen (O2) to produce monounsaturated fatty acyl-CoA, NADP+ and 2 molecules of water.
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This is used in some organic chemistry oxidations, e.g. in the Fenton's reagent. Only catalytic quantities of iron ion is needed since peroxide also oxidizes ferrous to ferric ion. The net reaction of hydrogen peroxide and permanganate or manganese dioxide is manganous ion; however, until the peroxide is spent some manganese ions are reoxidized to make the reaction catalytic.
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The matrix is host to a wide variety of metabolites involved in processes within the matrix. The citric acid cycle involves acyl-CoA, pyruvate, acetyl-CoA, citrate, isocitrate, α-ketoglutarate, succinyl-CoA, fumarate, succinate, L-malate, and oxaloacetate. The urea cycle makes use of ornithineL-ornithine, carbamoyl phosphate, and L-citrulline. The electron transport chain oxidizes coenzymes NADH and FADH2.
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This reaction oxidizes NADPH to NADP+. Sorbitol dehydrogenase can then oxidize sorbitol to fructose, which produces NADH from NAD+. Hexokinase can return the molecule to the glycolysis pathway by phosphorylating fructose to form fructose-6-phosphate. However, in uncontrolled diabetics that have high blood glucose - more than the glycolysis pathway can handle - the reactions mass balance ultimately favors the production of sorbitol.
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Thyroid peroxidase, also called thyroperoxidase (TPO) or iodide peroxidase, is an enzyme expressed mainly in the thyroid where it is secreted into colloid. Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine residues on thyroglobulin for the production of thyroxine (T4) or triiodothyronine (T3), the thyroid hormones. In humans, thyroperoxidase is encoded by the TPO gene.
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After oxygen, nitrate, manganeses, and iron are depleted, sulfate is the main electron acceptor used in anaerobic respiration. The metabolism associated with this is dissimilatory sulfate reduction (DSR) and is carried out by sulfur-reducing bacteria, which are widely distributed in anoxic environments. DSR oxidizes organic carbon using sulfate, and is described by the following equation: SO4^2- +2CH2O -> H2S +2HCO3^-.
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Candidatus Brocadia fulgida is a bacterial species that performs the anammox process. Fatty acids constitute an enrichment culture for B. fulgida. The species' 16S ribosomal RNA sequence has been determined. During the anammox process, it oxidizes acetate at the highest rate and out-competes other anammox bacteria which indicates that it doesn't incorporate acetate directly into their biomass like other anammox bacteria.
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The fruit bodies were noted to have insecticidal properties in a 1990 publication. Later research revealed the presence of a stearic acid ester that, upon injury to the mushrooms, coverts to an acrid phenol compound that oxidizes to a mixture of benzofuran and red chromene pigments. This is part of a wound-activated chemical defense system used by the fungus to deter mycophagy.
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On heating at 200 °C, phosphorous acid disproportionates to phosphoric acid and phosphine: :4 H3PO3 → 3 H3PO4 \+ PH3 This reaction is used for laboratory-scale preparations of PH3. Phosphorous acid slowly oxidizes in air to phosphoric acid. Both phosphorous acid and its deprotonated forms are good reducing agents, although not necessarily quick to react. They are oxidized to phosphoric acid or its salts.
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Nitrosomonas is a genus comprising Gram-negative, rod-shaped, and chemoautotrophic bacteria. This organism oxidizes ammonia into nitrite as a metabolic process, known as nitritation (a step of nitrification). Nitrosomonas are useful in a polluted water and waste treatment technique known as bioremediation. They are important in the nitrogen cycle as they increase the bioavailability of nitrogen to plants whilst limiting carbon fixation.
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Coelenterazine can be crystallized into orange- yellow crystals. The molecule absorbs light in the ultraviolet and visible spectrum, with peak absorption at 435 nm in methanol, giving the molecule a yellow color. The molecule spontaneously oxidizes in aerobic conditions or in some organic solvents such as dimethylformamide and DMSO and is preferentially stored in methanol or with an inert gas.
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Thermolithobacteria is a class of rod-shaped Gram-positive bacteria within phylum Firmicutes. Species within this class are thermophilic lithotrophs isolated from sediment in Calcite Springs in Yellowstone National Park. Thermolithobacter ferrireducens strain JW/KA-2(T) metabolism consists of the oxidation of hydrogen gas and reduction of ferric oxide to magnetite. Thermolithobacter carboxydivorans strain R1(T) is hydrogenic and oxidizes carbon monoxide.
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Scholle, Peter, 1979, Constituents, Textures, Cements, and Porosities of Sandstones and Associated Rocks, The American Association of Petroleum Geologists, Tulsa, OK, pp. 43–45 Chamosite is an olive-green color in thin section that readily oxidizes to limonite. When it is partially or fully oxidized to limonite, the green color becomes a yellowish-brown. Limonite is opaque under the microscope as well.
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Brown adipose tissue (BAT) oxidizes chemical energy to produce heat. This heat energy can act as a defense against hypothermia and obesity. PRDM16 is highly enriched in brown adipose cells as compared to white adipose cells, and plays a role in these thermogenic processes in brown adipose tissue. PRDM16 activates brown fat cell identity and can control the determination of brown adipose fate.
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In doing so it first oxidizes glucose and uses two electrons to reduce the FAD (a component of the enzyme) to FADH2. This in turn is oxidized by the electrode in a number of steps. The resulting current is a measure of the concentration of glucose. In this case, the electrode is the transducer and the enzyme is the biologically active component.
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Vitax Safety Data Sheet for Derris dust, revised October 1998 It oxidizes to rotenolone, which is about an order of magnitude less toxic than rotenone. In water, the rate of decomposition depends upon several factors, including temperature, pH, water hardness and sunlight. The half-life in natural waters ranges from half a day at 24 °C to 3.5 days at 0 °C.
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The mechanism is tentatively hypothesized to take place by the following steps: # The reduced di-iron coordinates oxygen, which oxidizes the iron and forms a peroxide species. # The peroxide species attacks the aldehyde. # An electron transfer coupled with cleavage of the peroxo species generates a hemi-acetal radical. # The terminal C-C bond cleaves homolytically to form the alkyl radical and release formate.
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The calcination of bastnäsite drives off the carbon dioxide content, leaving an oxide-fluoride, in which the cerium content oxidizes to the less-basic quadrivalent state. However, the high temperature of the calcination gives less-reactive oxide, and the use of hydrochloric acid, which can cause reduction of quadrivalent cerium, leads to an incomplete separation of cerium and the trivalent lanthanides.
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The compound reacts with water-based suppressors, and oxidizes even in the absence of atmospheric oxygen, rendering traditional atmosphere-displacement suppressors such as CO2 and halon ineffective. It ignites glass on contact. Exposure to larger amounts of chlorine trifluoride, as a liquid or as a gas, ignites living tissue. The hydrolysis reaction with water is violent and exposure results in a thermal burn.
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Coniine solidifies into a soft crystalline mass at −2 °C. It slowly oxidizes in the air. The salts crystallize well and are soluble in water or alcohol. The hydrochloride, B•HCl, crystallizes from water in rhombs, mp. 220 °C, [α]20°D +10.1°; the hydrobromide, in needles, mp. 211 °C, and the D-acid tartrate, B•C4H6O6•2 H2O, in rhombic crystals, mp.
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2-Mercaptopyridine is an organosulfur compound with the formula HSC5H4N. This yellow crystalline solid is a derivative of pyridine. The compound and its derivatives serve primarily as acylating agents. A few of 2-mercaptopyridine’s other uses include serving as a protecting group for amines and imides as well as forming a selective reducing agent. 2-Mercaptopyridine oxidizes to 2,2’-dipyridyl disulfide.
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Rubrene, like other polycyclic aromatic molecules, undergoes redox reactions in solution. It oxidizes and reduces reversibly at 0.95 V and −1.37 V, respectively vs SCE. When the cation and anion are co-generated in an electrochemical cell, they can combine with annihilation of their charges, but producing an excited rubrene molecule that emits at 540 nm. This phenomenon is called electrochemiluminescence.
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Progressing to the subacute stage, the following six weeks, hemoglobin oxidizes upon aging. This produces methemoglobin whose paramagnetic effect results in hematomas appearing hyperintense on T1- and T2-weighted images. In the chronic stage, the periphery of adrenal hematoma gradually becomes hyperintense, leaving a hypointense rim on T1- and T2-weighted images due to the hemosiderin deposition and development of a fibrous capsule.
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Dichromate and chromate salts are oxidizing agents. For the tanning of leather, sodium dichromate is first reduced with sulfur dioxide. In the area of organic synthesis, this compound oxidizes benzylic and allylic C-H bonds to carbonyl derivatives. For example, 2,4,6-trinitrotoluene is oxidized to the corresponding carboxylic acid. Similarly, 2,3-dimethylnaphthalene is oxidized by Na2Cr2O7 to 2,3-naphthalenedicarboxylic acid.
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Sodium and boiling amyl alcohol reduce it to a tetrahydroretene, but if it heated with phosphorus and hydriodic acid to 260 °C, a dodecahydride is formed. Chromic acid oxidizes it to retene quinone, phthalic acid and acetic acid. It forms a picrate that melts at 123-124 °C. Retene is derived by degradation of specific diterpenoids biologically produced by conifer trees.
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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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In the sulfate process, ilmenite is treated with sulfuric acid to extract iron(II) sulfate pentahydrate. The resulting synthetic rutile is further processed according to the specifications of the end user, i.e. pigment grade or otherwise. In another method for the production of synthetic rutile from ilmenite the Becher Process first oxidizes the ilmenite as a means to separate the iron component.
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H. halophila oxidizes sulfide to sulfur, which is deposited outside the cell and further oxidized to sulfate. H. halophila contains a large number of metabolic pathways, such as glycolysis, the citrate cycle, and amino acid metabolism. Its ability for photoautotrophic growth under extreme conditions, and it is distinguished by its characteristic sulfur metabolism. The proteome of H. halophila is highly acidic.
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Highly anisotropic thermal conductivity has been measured in three major principal crystal orientations and is effected by strain applied across the lattice. Exfoliated black phosphorus sublimes at 400 °C in vacuum. It gradually oxidizes when exposed to water in the presence of oxygen, which is a concern when contemplating it as a material for the manufacture of transistors, for example.
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As air is passed through this electrostatic field it is converted to ozone which oxidizes airborne contaminants.“New Weapons In The Fight Against Superbugs”, Medical News Today, May 2, 2007 Enclosing the ozone retains its ability to remove contaminants quickly while making it safe for populated environments.Edited by the Laboratorytalk editorial team. “Kill 99.7% of airborne bacteria and viruses”, August 12, 2005.
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Metallic plutonium is a fire hazard, especially if the material is finely divided. In a moist environment, plutonium forms hydrides on its surface, which are pyrophoric and may ignite in air at room temperature. Plutonium expands up to 70% in volume as it oxidizes and thus may break its container. The radioactivity of the burning material is an additional hazard.
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A solution containing ammonium thioglycolate contains a lot of free ammonia, which swells hair, rendering it permeable. The thioglycolic acid in the perm solution reduces the disulfide cystine bonds in the cortex of the hair. In a sense, the thioglycolate removes crosslinks. After washing, the hair is treated with a mild solution of hydrogen peroxide, which oxidizes the cysteines back to cystine.
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Bronzes are typically ductile alloys, considerably less brittle than cast iron. Typically bronze oxidizes only superficially; once a copper oxide (eventually becoming copper carbonate) layer is formed, the underlying metal is protected from further corrosion. This can be seen on statues from the Hellenistic period. However, if copper chlorides are formed, a corrosion-mode called "bronze disease" will eventually completely destroy it.
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CDO is responsible for the first major step in metabolism of cysteine. CDO oxidizes to cysteine sulfinic acid (which exists predominantly in the anionic sulfinate form in vivo). Overall, CDO catalyzes the addition of dioxygen (O2) to a thiol, producing a sulfinic acid. More specifically, CDO is part of the group of non-heme iron oxygenases that employ oxygen as an electron acceptor.
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With the production of the melanin, the skin color darkens, but can also cause sunburn. The tanning process can also be created by artificial UV radiation. There are two different mechanisms involved. Firstly, the UVA- radiation creates oxidative stress, which in turn oxidizes existing melanin and leads to rapid darkening of the melanin, also known as IPD (immediate pigment darkening).
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The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG. This initiates demethylation of 5mC as shown in the previous figure. For a TET enzyme to initiate demethylation it must first be recruited to a methylated CpG site in DNA.
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Sulfur can be removed from ores by roasting and washing. Roasting oxidizes sulfur to form sulfur dioxide which either escapes into the atmosphere or can be washed out. In warm climates it is possible to leave pyritic ore out in the rain. The combined action of rain, bacteria, and heat oxidize the sulfides to sulfuric acid and sulfates, which are water-soluble and leached out .
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In organic synthesis, K2FeO4 oxidizes primary alcohols.Green, J. R. “Potassium Ferrate” Encyclopedia of Reagents for Organic Synthesis 2001, John Wiley. . In contrast, related oxidants such as chromate are considered environmentally hazardous K2FeO4 has also attracted attention as a potential cathode material in a "super iron battery." Stabilised forms of potassium ferrate have been proposed for the removal of transuranic species, both dissolved and suspended, from aqueous solutions.
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The maximum in the wavelength of the luminescence is dependent on pH and salinity of the water in which the reaction takes place. It varies between 448 and 463 nm, with the maximum being at 452 nm in sea water. The substrate oxidizes when ejected from the upper-lip gland, with luciferase as a catalyst. The reaction produces carbon dioxide, oxyluciferin, and blue light.
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Lithium metal is soft enough to be cut with a knife. When cut, it possesses a silvery- white color that quickly changes to gray as it oxidizes to lithium oxide. While it has one of the lowest melting points among all metals (), it has the highest melting and boiling points of the alkali metals. Lithium has a very low density (0.534 g/cm3), comparable with pine wood.
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"Solder Joint Reliability of Gold Surface Finishes (ENIG, ENEPIG and DIG) for PWB Assembled with Lead Free SAC Alloy." Matte solder is usually fused to provide a better bonding surface for bare copper. Treatments, such as benzimidazolethiol, prevent surface oxidation of bare copper. The places to which components will be mounted are typically plated, because untreated bare copper oxidizes quickly, and therefore is not readily solderable.
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The mrl7 gene encodes for a NAD(P)+ dependent oxidoreductase (CitC). The first step of citrinin biosynthesis in fungi is the binding of citrinin synthase to the starting compound, a thiol ester. After that the serine hydrolase, encoded by mrl1, forms a ketoaldehyde at which CitB can work. CitB oxidizes the C-atom of a methyl group bound to the aromatic ring and produces an alcohol.
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This results in the formation of formyl-H4MPT. :HCO-MF + H4MPT -> HCO-H4MPT + MF Formyl-H4MPT is subsequently reduced to methenyl-H4MPT. Methenyl-H4MPT then undergoes a one- step hydrolysis followed by a two-step reduction to methyl-H4MPT. The two-step reversible reduction is assisted by coenzyme F420 whose hydride acceptor spontaneously oxidizes. Once oxidized, F420’s electron supply is replenished by accepting electrons from H2.
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If the tube with mineral oil doesn't change, and the open tube turns blue, then the organism neither ferments, nor oxidizes glucose. Instead, it is oxidizing peptones which liberates ammonia, turning the indicator blue. If only the aerobic tube has turned yellow then the organism is able to oxidase glucose aerobically ("O"). By-products: CO2 and although organic acids may be present at low rates.
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The serine family of amino acid includes: serine, cysteine, and glycine. Most microorganisms and plants obtain the sulfur for synthesizing methionine from the amino acid cysteine. Furthermore, the conversion of serine to glycine provides the carbons needed for the biosynthesis of the methionine and histidine. During serine biosynthesis, the enzyme phosphoglycerate dehydrogenase catalyzes the initial reaction that oxidizes 3-phospho-D- glycerate to yield 3-phosphonooxypyruvate.
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The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG. This initiates demethylation of 5mC as shown in the previous figure. For a TET enzyme to initiate demethylation it must first be recruited to a methylated CpG site in DNA.
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When a headliner fails, it sags or falls from the roof. One can use upholstery twist pins (a flat-headed corkscrew-like pin) to effect a temporary repair, but repairs usually involve tacking or replacing the entire headliner. Heat, humidity, and time rapidly degrade the bond that the polyurethane foam has with the face fabric. As the foam oxidizes and yellows, the fabric-foam bond fails.
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Barium manganate oxidizes a number of functional groups efficiently and selectively: alcohols to carbonyls, diols to lactones, thiols to disulfides, aromatic amines to azo-compounds, hydroquinone to p-benzoquinone, benzylamine to benzaldehyde, etc..Procter.G.; Ley, S. V.; Castle, G.H. (2004), "Barium Manganate", in Paquette,L., Encyclopedia of Reagents for Organic Synthesis, New York:Wiley, . It does not oxidize saturated hydrocarbons, alkenes, unsaturated ketones, and tertiary amines.
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Likewise the cathode reduces sodium ions (Na), which accept electrons from the cathode and deposits on the cathode as sodium metal. NaCl dissolved in water can also be electrolyzed. The anode oxidizes chloride ions (Cl), and Cl2 gas is produced. However, at the cathode, instead of sodium ions being reduced to sodium metal, water molecules are reduced to hydroxide ions (OH) and hydrogen gas (H2).
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SO3 is the anhydride of H2SO4. Thus, the following reaction occurs: :SO3 (g) \+ H2O (l) → H2SO4 (aq) (ΔHf = −200 kJ mol−1) The reaction occurs both rapidly and exothermically, too violently to be used in large-scale manufacturing. At or above 340 °C, sulfuric acid, sulfur trioxide, and water coexist in significant equilibrium concentrations. Sulfur trioxide also oxidizes sulfur dichloride to yield the useful reagent, thionyl chloride.
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In order to achieve protein fusion, the five-residue aldehyde tag (CxPxR) was incooperated into hIgG and hGH. In hIgG, the aldehyde tag was introduced at the C termini of the two heavy chains, resulting in two possible conjugation sites. FGE then oxidizes the cysteine residue to formylglycine (fGly) during protein expression. For the subsequent conjugation steps, the strategy of the copper-free click chemistry was selected.
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Aldehyde dehydrogenase, dimeric NADP-preferring is an enzyme that in humans is encoded by the ALDH3A1 gene. Aldehyde dehydrogenases oxidize various aldehydes to the corresponding acids. They are involved in the detoxification of alcohol-derived acetaldehyde and in the metabolism of corticosteroids, biogenic amines, neurotransmitters, and lipid peroxidation. The enzyme encoded by this gene forms a cytoplasmic homodimer that preferentially oxidizes aromatic aldehyde substrates.
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Sodium telluride is the chemical compound with the formula Na2Te. This salt is the conjugate base of the thermally unstable acid hydrogen telluride, but it is usually prepared by reduction of tellurium with sodium. Na2Te is a challenging material to handle because it is very sensitive to air. Air oxidizes it initially to polytellurides, which have the formula Na2Tex (x > 1), and ultimately Te metal.
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Because any fossils left in the ocean were ground up on the journey up, there are very few fossils to be found in the area. The sandstone is a medium-grained variety, and was originally light gray; however, the mica and clay in the rock oxidizes and turns a tan color. Not all of Chatsworth Formation has oxidized yet, and some is still light gray.
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The liver enzyme CYP3A4 oxidizes the methylidene group in position 6, and the 17-keto group (on the five-membered ring) is reduced by aldo-keto reductases to an alcohol. Of the resulting metabolites, 40% are excreted via the urine and 40% via the feces within a week. The original substance accounts for only 1% of excretion in the urine. The terminal half-life is 24 hours.
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Once there is no oxide coating left on the mercury blob, the surface tension increases and the blob rounds up and loses contact with the nail, to start the process over again. The net reaction is that the dichromate oxidizes the iron. This favorable reaction drives the mercury oxidations/reductions and the oscillations in shape. When the dichromate is all reduced, the reaction stops.
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While UHTCs have desirable thermal and mechanical properties, they are susceptible to oxidation at their elevated operating temperatures. The metal component oxidizes to a gas such as CO2 or NO2, which is rapidly lost at the elevated temperatures UHTCs are most useful at; boron, for example, readily oxidizes to B2O3 which becomes a liquid at 490 °C and vaporizes very rapidly above 1100 °C; in addition, their brittleness makes them poor engineering materials. Current research targets increasing their toughness and oxidation resistance by exploring composites with silicon carbide, the incorporation of fibers, and the addition of rare-earth hexaborides such as lanthanum hexaboride (LaB6). It has been found that the oxidative resistance of HfB2 and ZrB2 are greatly enhanced through the inclusion of 30% weight silicon carbide due to the formation of a protective glassy surface layer upon the application of temperatures in excess of 1000 °C composed of SiO2.
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The most confirmed function of plastid terminal oxidase in developed chloroplasts is its role in chlororespiration. In this process, NADPH dehydrogenase (NDH) reduces the quinone pool and the terminal oxidase oxidizes it, serving the same function as cytochrome c oxidase from mitochondrial electron transport. In Chlamydomonas, there are two copies of the gene for the oxidase. PTOX2 significantly contributes to the flux of electrons through chlororespiration in the dark.
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Gold is unaffected by most acids. It does not react with hydrofluoric, hydrochloric, hydrobromic, hydriodic, sulfuric, or nitric acid. It does react with selenic acid, and is dissolved by aqua regia, a 1:3 mixture of nitric acid and hydrochloric acid. Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable in the pure acid because of the chemical equilibrium of the reaction.
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Guanine has the C-6 carbonyl group that acts as the hydrogen bond acceptor, while a group at N-1 and the amino group at C-2 act as the hydrogen bond donors. Guanine can be hydrolyzed with strong acid to glycine, ammonia, carbon dioxide, and carbon monoxide. First, guanine gets deaminated to become xanthine. Guanine oxidizes more readily than adenine, the other purine-derivative base in DNA.
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SLC46A3 may be involved in plasma membrane electron transport (PMET), a plasma membrane analog of the mitochondrial electron transport chain (ETC) that oxidizes intracellular NADH and contributes to aerobic energy production by supporting glycolytic ATP production. The 3' UTR region of SLC46A3 includes a binding site for ENOX1, a protein highly involved in PMET. The C-(X)2-C motif in the protein sequence also suggests possible oxidoreductase activity.
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Curium readily oxidizes, and its oxides are a dominant form of this element. It forms strongly fluorescent complexes with various organic compounds, but there is no evidence of its incorporation into bacteria and archaea. When introduced into the human body, curium accumulates in the bones, lungs and liver, where it promotes cancer. All known isotopes of curium are radioactive and have a small critical mass for a sustained nuclear chain reaction.
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It also acts as an antioxidant and as a food flavor. It is an important compound in the transport of nitrate from the roots of a plant to the leaves of the plant. Potassium malate is the salt that transports from the leaves to the root. At the root the potassium maleate oxidizes to potassium carbonate, then is converted to potassium nitrate by soil nitrate and transported back to the leaves.
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Iridium atoms can also form a complex: cis-[(dppe)2IrS2]Cl with sodium periodate oxidizes to [(dppe)2IrS2O] and then to [(dppe)2IrS2O2], with dppe being 1,2-bis(diphenylphosphino)ethane. This substance has the S2O2 in a cis position. The same conditions can make a trans complex, but this contains two separate SO radicals instead. The iridium complex can be decomposed with triphenylphosphine to form triphenylphosphine oxide and triphenylphosphine sulfide.
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The metal is not attacked by sulfuric or hydrochloric acids. It dissolves in nitric acid with the evolution of nitric oxide gas to form dissolved Pb(NO3)2. : 3 Pb + 8 H+ \+ 8 → 3 Pb2+ \+ 6 + 2 NO + 4 H2O When heated with nitrates of alkali metals, metallic lead oxidizes to form PbO (also known as litharge), leaving the corresponding alkali nitrite. PbO is representative of lead's +2 oxidation state.
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Radium bromide is the bromide salt of radium, with the formula RaBr2. It is produced during the process of separating radium from uranium ore. This inorganic compound was discovered by Pierre and Marie Curie in 1898, and the discovery sparked a huge interest in radiochemistry and radiotherapy. Since elemental radium oxidizes readily in air and water, radium salts are the preferred chemical form of radium to work with.
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Plastocyanin (Cu2+Pc) is reduced (an electron is added) by cytochrome f according to the following reaction: :Cu2+Pc + e− → Cu+Pc After dissociation, Cu+Pc diffuses through the lumen space until recognition/binding occurs with P700+, at which point P700+ oxidizes Cu+Pc according to the following reaction: :Cu+Pc → Cu2+Pc + e− The redox potential is about 370 mV and the isoelectric pH is about 4.
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Copper used in buildings, usually for roofing, oxidizes to form a green verdigris (or patina). Copper is sometimes used in decorative art, both in its elemental metal form and in compounds as pigments. Copper compounds are used as bacteriostatic agents, fungicides, and wood preservatives. Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzyme complex cytochrome c oxidase.
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This physically removes many of the sulfur compounds, which are then vented. Exposure to oxygen in the air also oxidizes some of the compounds, creating atomic sulfur which can be filtered from the water. Aeration is also an effective means of removing radon from water. Small tanks and ponds for keeping aquatic animals such as fish or lobsters often rely on aeration to maintain sufficient level of oxygenation in the water.
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CD-RW/DVD-RWs (rewritable) are recordable, erasable and re-recordable discs that use a phase changing film data layer that reacts to heat. Laser light beams melt bits into the film to create data. These bits can be erased and re-recorded by adjusting the temperature of the laser. Rewritable CDs and DVDs usually use aluminium reflective layers, because the phase changing film degrades faster than aluminium oxidizes.
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Arsenic has a similar electronegativity and ionization energies to its lighter congener phosphorus and accordingly readily forms covalent molecules with most of the nonmetals. Though stable in dry air, arsenic forms a golden-bronze tarnish upon exposure to humidity which eventually becomes a black surface layer.Greenwood and Earnshaw, pp. 552–4 When heated in air, arsenic oxidizes to arsenic trioxide; the fumes from this reaction have an odor resembling garlic.
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The Porter Assay is a chemical test to help determine the potency of procyanidin containing compounds, such as grape seed extract. It is an acid hydrolysis, which splits larger chain units (dimers and trimers) into single unit monomers and oxidizes them. This leads to a colour change, which can be measured using a spectrophotometer. The greater the absorbance at a certain wavelength of light, the greater the potency.
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The blood flow is simply too strong for any device even compete with the flow, therefore the nanosubmarine would have to be carried by the blood. One form of propulsion nanosubmarines could use is electrochemical. One example of a motor is a nanorod which is platinum on one side and gold on the other. When submerged in hydrogen peroxide the platinum oxidizes the H2O2 into 2H+ and O2.
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The "silvering" on precision optical instruments such as telescopes is usually aluminum. Although aluminum also oxidizes quickly, the thin aluminum oxide (sapphire) layer is transparent, and so the high-reflectivity underlying aluminum stays visible. In modern aluminum silvering, a sheet of glass is placed in a vacuum chamber with electrically heated nichrome coils that can evaporate aluminum. In a vacuum, the hot aluminum atoms travel in straight lines.
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Plasma is a gas excited by electrical energy, and contains approximately an equal density of positive- and negative-charged ions. The interaction of the electrons and ions in the plasma with the surface oxidizes the surface and forms free radicals. The oxidation of the surface removes unwanted contaminants and improves adhesion. In addition to removing contaminates, the plasma treatment also introduces polar groups that increase the surface energy of the adherend.
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The thick smoke trails of the Black Eagles aerobatic team are made by releasing diesel and oil into the exhaust nozzle; this mixture immediately oxidizes, leaving a white smoke trail. There are two smoke tanks in the aircraft, each designed to carry about 60 gallon of smoke oil. The smoke system can control the quantity of oil released, so each aircraft can trail smoke for seven to twenty minutes.
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Lactoferrin's primary role is to sequester free iron, and in doing so remove essential substrate required for bacterial growth. Antibacterial action of lactoferrin is also explained by the presence of specific receptors on the cell surface of microorganisms. Lactoferrin binds to lipopolysaccharide of bacterial walls, and the oxidized iron part of the lactoferrin oxidizes bacteria via formation of peroxides. This affects the membrane permeability and results in the cell breakdown (lysis).
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Niobium, also known as columbium, is a chemical element with the symbol Nb (formerly Cb) and atomic number 41. Niobium is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs hardness rating similar to that of pure titanium, and it has similar ductility to iron. Niobium oxidizes in the earth's atmosphere very slowly, hence its application in jewelry as a hypoallergenic alternative to nickel.
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This reaction is exploited in the Claus process, an important industrial method to dispose of hydrogen sulfide. Hydrogen sulfide is slightly soluble in water and acts as a weak acid (pKa = 6.9 in 0.01–0.1 mol/litre solutions at 18 °C), giving the hydrosulfide ion (also written ). Hydrogen sulfide and its solutions are colorless. When exposed to air, it slowly oxidizes to form elemental sulfur, which is not soluble in water.
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In contrast to noble metals, base metals may be distinguished by oxidizing or corroding relatively easily and reacting variably with diluted hydrochloric acid (HCl) to form hydrogen. Examples include iron, nickel, lead and zinc. Copper is also considered a base metal because it oxidizes relatively easily, although it does not react with HCl. In mining and economics, the term base metals refers to industrial non- ferrous metals excluding precious metals.
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Generally, 1–2 wt. % of [Ca(NO2)2] with respect to cement weight is needed to prevent corrosion of the rebars. The nitrite anion is a mild oxidizer that oxidizes the soluble and mobile ferrous ions (Fe2+) present at the surface of the corroding steel and causes them to precipitate as an insoluble ferric hydroxide (Fe(OH)3). This causes the passivation of steel at the anodic oxidation sites.
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DsbA, DsbC and DsbG have a common Cys-Xxx-Xxx- Cys (Cys-Cysteine) motif in their active site, where Xxx can be any amino acid. In the periplasm, DsbA oxidizes thiols in cysteines to form disulfide bonds in proteins. DsbA receives its oxidizing potential from the cytosol through DsbB. However, the probability of forming a non-native disulfide bond increases with the number of cysteines in the protein sequence.
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The high temperature stability, low vapor pressure, good wear resistance and ability to withstand arc corrosion of rhenium are useful in self-cleaning electrical contacts. In particular, the discharge that occurs during electrical switching oxidizes the contacts. However, rhenium oxide Re2O7 has poor stability (sublimes at ~360 °C) and therefore is removed during the discharge. Rhenium has a high melting point and a low vapor pressure similar to tantalum and tungsten.
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European Journal of Mineralogy.18, 793-801 Santabarbaraite occurs as pseudomorphic masses after vivianite (Fe2+3(PO4)2·8H2O). In the process, monoclinic vivianite oxidizes to form the amorphous santabarbaraite. Pseudomorphism can be seen in Victoria, Australia in Wannon Falls which is originally a well-known locality for vivianite and at Lake Baikal, Siberia where the oxidized santabarbaraite can be seen as a rim surrounding vivianite due to exposure to air.
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Another suggestion was that cells with a deficiency in cytochrome c oxidase are apoptosis resistant, and thus more likely to survive. The linkage of MT-COI to apoptosis arises because active cytochrome c oxidase oxidizes cytochrome c, which then activates pro-caspase 9, leading to apoptosis. These two factors may contribute to the frequent occurrence of MT-COI-deficient colonic crypts with age or during carcinogenesis in the human colon.
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Monoamine oxidase (MAO) is an extensively studied flavoenzyme due to its biological importance with the catabolism of norepinephrine, serotonin and dopamine. MAO oxidizes primary, secondary and tertiary amines, which nonenzymatically hydrolyze from the imine to aldehyde or ketone. Even though this class of enzyme has been extensively studied, its mechanism of action is still being debated. Two mechanisms have been proposed: a radical mechanism and a nucleophilic mechanism.
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It oxidizes to nitrogen dioxide within a few minutes, which has a yellow or reddish-brown color depending on concentration and smells of chlorine gas like a swimming pool. Ozone is invisible but has a pungent smell like that of the air after a lightning storm. It is a short-lived species and half of it breaks down into within a day at normal temperatures and atmospheric pressure.
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Its surface readily oxidizes in air at room temperature, giving an SiO2 surface layer that protects the material from further oxidation. However, (SiO)n irreversibly disproportionates into SiO2 and Si in a few hours between 400 and 800°C, and very rapidly between 1,000 and 1,440°C, although the reaction does not go to completion.W. Hertl and W. W. Pultz, J. Am. Ceramic Soc. Vol. 50, Issue 7, (1967) pp. 378-381.
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MPO is a member of the XPO subfamily of peroxidases and produces hypochlorous acid (HOCl) from hydrogen peroxide (H2O2) and chloride anion (Cl−) (or hypobromous acid if Br- is present) during the neutrophil's respiratory burst. It requires heme as a cofactor. Furthermore, it oxidizes tyrosine to tyrosyl radical using hydrogen peroxide as an oxidizing agent. Hypochlorous acid and tyrosyl radical are cytotoxic, so they are used by the neutrophil to kill bacteria and other pathogens.
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In this oxidation-reduction reaction, the oxidizing agent can be sodium amalgam, which reduces oxalic acid, while the reducing agent is nitric acid, which oxidizes an alcohol. Reduction of the oxalic acid is done in a sulphuric acid solution while avoiding a temperature increase inside the cathode. Once the reduction has ended, the oxalic acid is diminished and the freed glyoxylic acid produces the indol molecules, which gives the red/purple color.
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Three key proteins have been deemed as markers for BCSCs: CD44, CD24 and aldehyde dehydrogenase (ALDH). CD44, a cell surface glycoprotein, plays a crucial role in the adhesion, migration and invasion of breast cancer cells. In addition to its ability to promote proliferation and metastasis, the interaction of this protein with osteopontin hastens tumor progression. ALDH, a family of enzymes that oxidizes intracellular aldehydes and retinol, aids in the differentiation of stem cells.
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The third reaction, known as radical consumption layer, where most of the heat is released, and the first reaction, also known as fuel consumption layer, occur in a narrow region at the flame. The fourth reaction is the hydrogen oxidation layer, whose thickness is much larger than the former two layers. Finally, the carbon monoxide oxidation layer is the largest of them all, corresponding to the second reaction, and oxidizes very slowly.
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The presence of pyrite in the aggregate used to make concrete can lead to severe deterioration as pyrite oxidizes. In early 2009, problems with Chinese drywall imported into the United States after Hurricane Katrina were attributed to pyrite oxidation, followed by microbial sulfate reduction which released hydrogen sulfide gas. These problems included a foul odor and corrosion of copper wiring.Angelo, William (28 January 2009) A Material Odor Mystery Over Foul-Smelling Drywall.
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Tetracycline is a broad spectrum antibiotic, and its derivative minocycline is common in the treatment of acne. The drug is able to chelate calcium ions and is incorporated into teeth, cartilage and bone. Ingestion during the years of tooth development causes a yellow-green discoloration of dentin, which is visible through the enamel and fluorescent under ultraviolet light. Later, the tetracycline oxidizes and the staining becomes more brown and no longer fluoresces under UV light.
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Ho2O3, left: natural light, right: under a cold- cathode fluorescent lamp Holmium is a relatively soft and malleable element that is fairly corrosion-resistant and stable in dry air at standard temperature and pressure. In moist air and at higher temperatures, however, it quickly oxidizes, forming a yellowish oxide. In pure form, holmium possesses a metallic, bright silvery luster. Holmium oxide has some fairly dramatic color changes depending on the lighting conditions.
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The trihydrate salt is obtained as a reddish-brown precipitate by adding potassium cyanide to a cobalt salt solution.:John H. Bigelow, "Potassium Hexacyanocobaltate(III)" Inorganic Syntheses, 1946, Volume I1, p. 225. :CoCl2(H2O)6 \+ 2 KCN → Co(CN)2 \+ 2 KCl + 6 H2O Hydrated Co(CN)2 dissolves in the presence of excess potassium cyanide, forming a red solution of K4Co(CN)6. This material further oxidizes to yellow K3Co(CN)6.
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In the main porphyrin biosynthesis pathway, coproporphyrinogen III is derived from uroporphyrinogen III by the action of the enzyme uroporphyrinogen III decarboxylase: alt=Biosynthesis of coproporphyrinogen-III from uroporphyrinogen-III The conversion entails four decarboxylations, which turn the four acetic acid groups into methyl groups , with release of four carbon dioxide molecules. Coproporphyrinogen III is further used as a substrate for the enzyme coproporphyrinogen III oxidase which oxidizes and further decarboxylates it to protoporphyrinogen IX.
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One approach to molecular memories is based on special compounds such as porphyrin-based polymers which are capable of storing electric charge. Once a certain voltage threshold is achieved the material oxidizes, releasing an electric charge. The process is reversible, in effect creating an electric capacitor. The properties of the material allow for a much greater capacitance per unit area than with conventional DRAM memory, thus potentially leading to smaller and cheaper integrated circuits.
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CooA is a heme-containing transcription factor that responds to the presence of carbon monoxide. It induces the expression of carbon monoxide dehydrogenase, which oxidizes CO. In the inactive ferric state, iron is bound to cysteine thiolate and the amine of an N-terminal proline, in addition to the N4 donor set of the porphyrinate. In the reduced state, an imidazole of histidine displaces the thiolate. The midpoint potential is -300 mV.
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It participates in homolytic cleavage of the O-O bond in the endoperoxide, which represents the rate-limiting step, and undergoes a change in redox state from Fe(III) to Fe(IV). A free oxygen radical forms at C-11, and this intermediate undergoes ring cleavage. With the free radical now at C-12, the iron heme then oxidizes this radical to a carbocation. The molecule is now ready for intramolecular ring formation.
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The mechanism involves two steps, each of which forms one of the phenylhydrazone functionalities. In the first step, a molecule of phenylhydrazine reacts with the carbonyl group on the sugar to form a phenylhydrazone by elimination of a water molecule. The next step involves two molecules of phenylhydrazine. The first oxidizes the hydroxy group on the reactive alpha carbon to a carbonyl group, and the second then forms a hydrazone with it.
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The montroseite, VO(OH), is deposited in crystalline masses in a sandstone matrix by some unknown process. Usually iron occurs in place of some of the vanadium. Oxygen in the air or groundwater then oxidizes the crystallised montroseite at temperatures under 50 °C through the reaction: :2VO(OH) + O2 → 2VO2 \+ H2O During the solid state alteration process the hydrogen atoms migrate through the crystal structure to the surface, where they combine with oxygen.
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Benzyl alcohol has low acute toxicity with an of 1.2 g/kg in rats. It oxidizes rapidly in healthy individuals to benzoic acid, conjugated with glycine in the liver, and excreted as hippuric acid. Very high concentrations can result in toxic effects including respiratory failure, vasodilation, hypotension, convulsions, and paralysis. Benzyl alcohol is toxic to neonates and is associated with the gasping syndrome... Benzyl alcohol is severely toxic and highly irritating to the eye.
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Pyrolusite is also used to prepare disinfectants (permanganates) and for decolorizing glass. When mixed with molten glass it oxidizes the ferrous iron to ferric iron, and so discharges the green and brown tints (making it classically useful to glassmakers as a decolorizer). As a coloring material, it is used in calico printing and dyeing; for imparting violet, amber, and black colors to glass, pottery, and bricks; and in the manufacture of green and violet paints.
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It is soluble in concentrated sulfuric acid with a green color. Chromic acid in glacial acetic acid solution oxidizes it to picene-quinone, picene-quinone carboxylic acid, and finally to phthalic acid. When intercalated with potassium or rubidium and cooled to below 18 K, picene has been reported to exhibit superconductive properties. However, due to the apparent inability to reproduce this work, the superconducting nature of doped picene has been met with heavy scepticism.
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A large amount of water with high speed and temperature of 38-40 °C is circulated in jackets. The cylinder also has an air vacuum chamber, which removes air bubbles from the dough before extruding. Otherwise small bubbles will form in the pasta and decreases the mechanical strength which cause breakage from hours to days after drying. The air also oxidizes the carotenoid or xanthophyll, which results in a white, chalky appearance of the pasta.
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The terbium(III) cation is brilliantly fluorescent, in a bright lemon-yellow color that is the result of a strong green emission line in combination with other lines in the orange and red. The yttrofluorite variety of the mineral fluorite owes its creamy-yellow fluorescence in part to terbium. Terbium easily oxidizes, and is therefore used in its elemental form specifically for research. Single terbium atoms have been isolated by implanting them into fullerene molecules.
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Fehling's solution can be used to distinguish aldehyde vs ketone functional groups. The compound to be tested is added to the Fehling's solution and the mixture is heated. Aldehydes are oxidized, giving a positive result, but ketones do not react, unless they are α-hydroxy ketones. The bistartratocuprate(II) complex oxidizes the aldehyde to a carboxylate anion, and in the process the copper(II) ions of the complex are reduced to copper(I) ions.
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This gene is one of three related genes that have 2-hydroxyacid oxidase activity yet differ in encoded protein amino acid sequence, tissue expression and substrate preference. Subcellular location of the encoded protein is the peroxisome. Specifically, this gene is expressed primarily in liver and pancreas and the encoded protein is most active on glycolate, a two-carbon substrate. Glycolate oxidase oxidizes glycolic acid to glyoxylate, and can also oxidize glyoxylate into oxalate.
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The oil comprises many constituent chemicals and its composition changes if it is exposed to air and oxidizes. Commercial use of tea tree oil began in the 1920s, pioneered by the entrepreneur Arthur Penfold. the global tea tree oil market was valued at US$39 million. As a traditional medicine, it is typically used as a topical medication in low concentrations for the attempted treatments of skin conditions, but there is little evidence of efficacy.
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Gadolinite Holmium oxide occurs in trace amounts in the minerals gadolinite, monazite, and in other rare-earth minerals. Holmium metal readily oxidizes in air; therefore presence of holmium in nature is synonymous with that of holmia. With the abundance of 1.4 mg/kg, holmium is the 56th most abundant element. The main mining areas are China, United States, Brazil, India, Sri Lanka and Australia with reserves of holmium oxide estimated as 400,000 tonnes.
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When exposed to air, the radical rapidly oxidizes to the peroxide, and the color of the solution changes from yellow to colorless. Likewise, the radical reacts with iodine to triphenylmethyl iodide. Triphenylmethyl radical oxidationWhile the trityl radical forms a quinoid dimer, derivatives thereof with the appropriate substitution pattern do form dimers with a hexaphenylethane structure. X-ray studies give a bond length of 1.67 Å for hexakis(3,5-di-t-butylphenyl)ethane.
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The oxygen oxidizes the hydroquinones and also acts as the propellant. The oxidation reaction is very exothermic (ΔH = −202.8 kJ/mol) and rapidly heats the mixture to the boiling point. Long-lived queens of the termite Reticulitermes speratus have significantly lower oxidative damage to their DNA than non-reproductive individuals (workers and soldiers). Queens have more than two times higher catalase activity and seven times higher expression levels of the catalase gene RsCAT1 than workers.
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Ceruloplasmin also oxidizes iron from its ferrous state to the ferric form that is required for iron binding. Impairment in these copper dependent enzymes that transport iron may cause the secondary iron deficiency anemia. Another speculation for the cause of anemia is involving the mitochondrial enzyme cytochrome c oxidase (complex IV in the electron transport chain). Studies have shown that animal models with impaired cytochrome c oxidase failed to synthesize heme from ferric iron at the normal rate.
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Interest in this highly corrosive compound began in the fifties when there were extensive studies of its physicochemical properties. It is a powerful fluorinating and oxidizing agent. It oxidizes elemental sulfur to sulfur tetrafluoride:. :S + 4 VF5 → 4 VF4 \+ SF4 Like other electrophilic metal halides, it hydrolyzes, first to the oxyhalide: :VF5 \+ H2O → VOF3 \+ 2 HF Then to the binary oxide: :2 VOF3 \+ 3 H2O → V2O5 \+ 6 HF Hydrolysis is accelerated in the presence of base.
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Zipping up the orifice is a reversal of the steps required to open the cage. Care must be taken to keep the reaction conditions below 160 °C on order to prevent hydrogen from escaping. m-CPBA oxidizes the sulfur group to a sulfoxide group which can then be extracted from the ring by a photochemical reaction under visible light in toluene. The two ketone groups are re-coupled in a McMurry reaction with titanium tetrachloride and elemental zinc.
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Acting as a co-substrate for α-ketoglutarate-dependent hydroxylase, it also plays important function in oxidation reactions involving molecular oxygen. Molecular oxygen (O2) directly oxidizes many compounds to produce useful products in an organism, such as antibiotics, in reactions catalyzed by oxygenases. In many oxygenases, α-ketoglutarate helps the reaction by being oxidized with the main substrate. EGLN1, one of the α-ketoglutarate-dependent oxygenases, is an O2 sensor, informing the organism the oxygen level in its environment.
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An automotive oil-cooled turbocharger is a typical example. Turbochargers get red hot during operation and the oil that is cooling them only survives as its residence time in the system is very short (i.e. high flow rate). If the system is shut down suddenly (pulling into a service area after a high-speed drive and stopping the engine) the oil that is in the turbo charger immediately oxidizes and will clog the oil ways with deposits.
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Finely powdered pure aluminium oxidizes rapidly in air, generating a huge amount of heat in the process (burning at about or ), leading to applications in welding and elsewhere that a large amount of heat is needed. Aluminium is a component of alloys used for making lightweight bodies for aircraft. Cars also sometimes incorporate aluminium in their framework and body, and there are similar applications in military equipment. Less common uses include components of decorations and some guitars.
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The pH of an alkaline soil can be reduced by adding acidifying agents or acidic organic materials. Elemental sulfur (90–99% S) has been used at application rates of 300–500 kg/ha – it slowly oxidizes in soil to form sulfuric acid. Acidifying fertilizers, such as ammonium sulfate, ammonium nitrate and urea, can help to reduce the pH of a soil because ammonium oxidises to form nitric acid. Acidifying organic materials include peat or sphagnum peat moss.
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The postulated reaction mechanism is explained below for the example of 2-hydroxyanthraquinone: Bohn–Schmidt reaction mechanism The sulfuric acid protonates the keto group of the anthraquinone 1. This causes a shift of the electrons to the oxonium ion in molecule 2. This shift enables the sulfuric acid to attack the carbenium ion 3 which is formed. The sulfuric acid oxidizes the resulting hydroxyanthracenone 5, which is then protonated and the reaction starts all over again.
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4-Aminophenol (or para-aminophenol or p-aminophenol) is the organic compound with the formula H2NC6H4OH. Typically available as a white powder,CRC Handbook of Chemistry and Physics 65th Ed. it was commonly used as a developer for black-and-white film, marketed under the name Rodinal. Reflecting its slightly hydrophilic character, the white powder is moderately soluble in alcohols and can be recrystallized from hot water. In the presence of a base, it oxidizes readily.
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Consistent with earlier isotopic studies, the PBP halopyrrole biosynthesis via the bmp pathway begins with L-proline. In this module, L-proline is acylated to the acyl carrier protein domain of Bmp1 (ACP-thioesterase (TE) di-domain protein) by the proline adenyl transferase Bmp4 (A). The flavin-dependent dehydrogenase, Bmp3 (DH), then oxidizes the prolyl ring to a pyrrole. The loaded protein is then tri-brominated with the flavin-dependent halogenase, Bmp2 (Hal), becoming 2,3,4,5-tetrabromopyrrole.
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Yılmaz, M.; Yılmaz, E. V. B.; Pekel, A. T. Helv. Chim. Acta 2011, 94, 2027-2038. Stoichiometry is important to consider for these reactions, as two equivalents of oxidant are required if carbocation intermediates are desired (because Mn(OAc)3 is a one-electron oxidant). A second equivalent of manganese(III) acetate is also required if copper(II) acetate is used as a co- catalyst, because Mn(OAc)3 re-oxidizes Cu(I) to Cu(II).
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Lactic acid fermentation converts pyruvate to lactate by lactate dehydrogenase. Most importantly, fermentation regenerates NAD+, maintaining its concentration so additional glycolysis reactions can occur. The fermentation step oxidizes the NADH produced by glycolysis back to NAD+, transferring two electrons from NADH to reduce pyruvate into lactate. (Refer to the main articles on glycolysis and fermentation for the details.) Instead of accumulating inside the muscle cells, lactate produced by anaerobic fermentation is taken up by the liver.
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349, 365 center Biosynthesis of ergot alkaloids begins with the alkylation of tryptophan by dimethylallyl pyrophosphate (DMAPP), where the carbon atom C(4) in the indole nucleus plays the role of the nucleophile. The resulting 4-dimethylallyl-L-tryptophan undergoes N-methylation. Further products of biosynthesis are chanoclavine-I and agroclavine – the latter is hydroxylated to elymoclavine, which in turn oxidizes into paspalic acid. In the process of allyl rearrangement, paspalic acid is converted to lysergic acid.
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VAMTOX systems have a system of valves and dampers that direct the methane flow across the ceramic bed. On system start up, the system preheats and raises the temperature of the heat exchange material in the oxidizer bed to or above the auto-oxidation temperature of methane (1,000 °C or 1,832 °F). Then the preheating system is turned off and mine exhaust air is introduced. When the methane-filled air reaches the preheated bed, it oxidizes and releases heat.
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Aeromonas salmonicida is a Gram-negative, facultatively anaerobic, nonmotile bacterium. It is rod-shaped, about 1.3–2.0 by 0.8–1.3 μm in size, and grows optimally at temperatures between 22 and 25 °C. The bacterium readily ferments and oxidizes glucose, and is catalase- and cytochrome oxidase-positive. Its molecular properties include a special surface protein array called the A-layer, which is believed to be responsible for the bacterium's virulent traits, and lipopolysaccharide, the cells' major cell envelope antigen.
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OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG. This initiates demethylation of 5mC. Demethylation of 5-Methylcytosine (5mC) in neuron DNA. As reviewed in 2018, in brain neurons, 5mC is oxidized by the ten- eleven translocation (TET) family of dioxygenases (TET1, TET2, TET3) to generate 5-hydroxymethylcytosine (5hmC). In successive steps TET enzymes further hydroxylate 5hmC to generate 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC).
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A rare explosive form of antimony can be formed from the electrolysis of antimony trichloride. When scratched with a sharp implement, an exothermic reaction occurs and white fumes are given off as metallic antimony forms; when rubbed with a pestle in a mortar, a strong detonation occurs. Black antimony is formed upon rapid cooling of antimony vapor. It has the same crystal structure as red phosphorus and black arsenic; it oxidizes in air and may ignite spontaneously.
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When the hydrogen peroxide is dripped on to the guaiac paper, it oxidizes the alpha- guaiaconic acid to a blue colored quinone. Normally, when no blood and no peroxidases or catalases from vegetables are present, this oxidation occurs very slowly. Heme, a component of hemoglobin found in blood, catalyzes this reaction, giving a result in about two seconds. Therefore, a positive test result is one where there is a quick and intense blue color change of the film.
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Sulfite oxidase () is an enzyme in the mitochondria of all eukaryotes, with exception of the yeasts. It oxidizes sulfite to sulfate and, via cytochrome c, transfers the electrons produced to the electron transport chain, allowing generation of ATP in oxidative phosphorylation. This is the last step in the metabolism of sulfur-containing compounds and the sulfate is excreted. Sulfite oxidase is a metallo-enzyme that utilizes a molybdopterin cofactor and a heme group (in a case of animals).
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Without oxygen, pyruvate (pyruvic acid) is not metabolized by cellular respiration but undergoes a process of fermentation. The pyruvate is not transported into the mitochondrion, but remains in the cytoplasm, where it is converted to waste products that may be removed from the cell. This serves the purpose of oxidizing the electron carriers so that they can perform glycolysis again and removing the excess pyruvate. Fermentation oxidizes NADH to NAD+ so it can be re-used in glycolysis.
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Retinoic acid signaling is also important for maintaining adult neuronal and epithelium cell type. Retinoic acid is generated in organisms by first oxidizing retinol (Vitamin A) to retinal with an alcohol dehydrogenase. Then, a retinal dehydrogenase oxidizes retinal to retinoic acid. The production of retinoic acid from vitamin A must be tightly controlled as high levels of retinoic acid and vitamin A can lead to toxic effects, while vitamin A deficiency leads to its own issues in development.
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Osmium is usually sold as a minimum 99.9% pure powder. Like other precious metals, it is measured by troy weight and by grams. The market price of osmium has not changed in decades, primarily because little change has occurred in supply and demand. In addition to so little of it being available, osmium is difficult to work with, has few uses, and is a challenge to store safely because of the toxic compound it produces when it oxidizes.
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The major disadvantage of mirror diagonals is that unless the reflective coating is properly applied they can scatter light rendering lower image contrast compared to a 90-degree prism. Also they deteriorate with age as the reflective surface oxidizes. The newer Dielectric mirrors have largely solved the deterioration problem, and if properly made the Dielectric mirrors scatter less light compared to conventional mirrors. With short focal length instruments a mirror diagonal is preferred over a prism.
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The use of chelating agents like EDTA to remove some of these metal ions from the pulp prior to adding peroxide allows the peroxide to be used more efficiently. Magnesium salts and sodium silicate are also added to improve bleaching with alkaline peroxide. Sodium dithionite (Na2S2O4), also known as sodium hydrosulfite, is the other main reagent used to brighten mechanical pulps. In contrast to hydrogen peroxide, which oxidizes the chromophores, dithionite reduces these color-causing groups.
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The orientation of the silicon crystal affects oxidation. A <100> wafer (see Miller indices) oxidizes more slowly than a <111> wafer, but produces an electrically cleaner oxide interface. Thermal oxidation of any variety produces a higher-quality oxide, with a much cleaner interface, than chemical vapor deposition of oxide resulting in low temperature oxide layer (reaction of TEOS at about 600 °C). However, the high temperatures required to produce High Temperature Oxide (HTO) restrict its usability.
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Bog ore often combines goethite, magnetite, and vugs or stained quartz. Oxidation may occur through enzyme catalysis by iron bacteria. It is not clear whether the magnetite precipitates upon first contact with oxygen, then oxidizes to ferric compounds, or whether the ferric compounds are reduced when exposed to anoxic conditions upon burial beneath the sediment surface and reoxidized upon exhumation at the surface. Bog iron, like other hydrous iron oxides, has a specific affinity for heavy metals.
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Potassium permanganate (KMnO4) is a very strong oxidant able to react with many functional groups, such as secondary alcohols, 1,2-diols, aldehydes, alkenes, oximes, sulfides and thiols. Under controlled conditions, KMnO4 oxidizes primary alcohols to carboxylic acids very efficiently. This reaction, which was first described in detail by Fournier, is typically carried out by adding KMnO4 to a solution or suspension of the alcohol in an alkaline aqueous solution. The resulting mixture is stirred until the oxidation is complete.
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One hypothesis is that the source may be the remains of an ancient fjord that occupied the Taylor valley in the tertiary period. The ferrous iron dissolved in the water oxidizes as the water reaches the surface, turning the water red. Its autotrophic bacteria metabolize sulfate and ferric ions. According to geomicrobiologist Jill Mikucki at the University of Tennessee, water samples from Blood Falls contained at least 17 different types of microbes and almost no oxygen.
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The systematic name of this enzyme class is retinol:NAD+ oxidoreductase. Other names in common use include retinol (vitamin A1) dehydrogenase, MDR, microsomal retinol dehydrogenase, all-trans retinol dehydrogenase, retinal reductase, and retinene reductase. This enzyme participates in retinol metabolism. Occasionally, the literature refers to retinol dehydrogenase as an enzyme that oxidizes retinol in general, such as class IV alcohol dehydrogenase (ADH4), which reportedly is the most efficient retinol oxidation in the human alcohol dehydrogenase (ADH) family.
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Molybdenum oxidizes much faster than tungsten and quickly develops a thick oxide layer that does not adhere well, its oxidation should be therefore limited to just yellowish or at most blue-green color. The oxide is volatile and evaporates as a white smoke above 700 °C; excess oxide can be removed by heating in inert gas (argon) at 1000 °C. Molybdenum strips are used instead of wires where higher currents (and higher cross-sections of the conductors) are needed.
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The C1orf123 protein has no transmembrane regions so is therefore likely not a transmembrane protein. Three post-translational modification sites have been experimentally found, including a phosphotyrosine, phosphoserine, and glycyl- lysine isopeptide. A portion of the 3' UTR of C1orf123 has 100% identity with the mRNA for Homo sapiens carnitine palmityoyltransferase 2 is a nuclear gene that encodes mitochondrial protein. This gene works with carnitine palmitoyltransferase I, and the encoded protein oxidizes long-chain fatty acids in the mitochondria.
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The complex is prepared by reduction of anhydrous nickel(II) acetylacetonate in the presence of the diolefin: :Ni(acac)2 \+ 2 cod + 2 AlEt3 → Ni(cod)2 \+ 2 acacAlEt2 \+ C2H6 \+ C2H4 Ni(cod)2 is moderately soluble in several organic solvents. One or both 1,5-cyclooctadiene ligands are readily displaced by phosphines, phosphites, bipyridine, and isocyanides. If exposed to air, the solid oxidizes to nickel(II) oxide. As a result, this compound is generally handled in a glovebox.
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PMC rely on the formation of a metallic conductive filament to transition to a low resistance state (LRS). The filament is created by applying a positive voltage bias (V) to the anode contact (active metal) while grounding the cathode contact (inert metal). The positive bias oxidizes the active metal (M): :M → M+ \+ e− The applied bias generates an electric field between the two metal contacts. The ionized (oxidized) metal ions migrate along the electric field toward the cathode contact.
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OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG. This initiates demethylation of 5mC. Demethylation of 5-Methylcytosine (5mC) in neuron DNA. As reviewed in 2018, in brain neurons, 5mC is oxidized by the ten-eleven translocation (TET) family of dioxygenases (TET1, TET2, TET3) to generate 5-hydroxymethylcytosine (5hmC). In successive steps TET enzymes further hydroxylate 5hmC to generate 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC).
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Cysteine dioxygenase (CDO) is a non-heme iron enzyme that catalyzes the conversion of L-cysteine to cysteine sulfinic acid (cysteine sulfinate). CDO plays an important role in cysteine catabolism, regulating intracellular levels of cysteine and responding changes in cysteine availability. As such, CDO is highly regulated and undergoes large changes in concentration and efficiency. It oxidizes cysteine to the corresponding sulfinic acid by activation of dioxygen, although the exact mechanism of the reaction is still unclear.
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Ammonia removal occurs in constructed wetlands – if they are designed to achieve biological nutrient removal – in a similar ways as in sewage treatment plants, except that no external, energy-intensive addition of air (oxygen) is needed. It is a two-step process, consisting of nitrification followed by denitrification. The nitrogen cycle is completed as follows: ammonia in the wastewater is converted to ammonium ions; the aerobic bacterium Nitrosomonas sp. oxidizes ammonium to nitrite; the bacterium Nitrobacter sp.
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Initiation of DNA demethylation at a CpG site. In adult somatic cells DNA methylation typically occurs in the context of CpG dinucleotides (CpG sites), forming 5-methylcytosine-pG, or 5mCpG. Reactive oxygen species (ROS) may attack guanine at the dinucleotide site, forming 8-hydroxy-2'-deoxyguanosine (8-OHdG), and resulting in a 5mCp-8-OHdG dinucleotide site. The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG. This initiates demethylation of 5mC. The figure in this section shows a CpG site where the cytosine is methylated to form 5-methylcytosine (5mC) and the guanine is oxidized to form 8-oxo-2'-deoxyguanosine (in the figure this is shown in the tautomeric form 8-OHdG). When this structure is formed, the base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1, and TET1 oxidizes the 5mC adjacent to the 8-OHdG.
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Fuel cells are made up of three sandwiched segments: an anode, an electrolyte, and a cathode, in a reaction cell where electricity is produced inside the fuel cells through the reactions between an external fuel and an oxidant in the presence of an electrolyte. The anode hosts a catalyst that oxidizes the fuel, turning the fuel into positively charged ions and negatively charged electrons. This fuel is typically hydrogen, hydrocarbons, and alcohols. The electrolyte blocks the transportation of electrons while conducting ions.
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This gene encodes L-2-hydroxyglutarate dehydrogenase, a flavin adenine dinucleotide (FAD)-dependent enzyme that oxidizes L-2-hydroxyglutarate to alpha-ketoglutarate in a variety of mammalian tissues. Mutations in this gene cause L-2-hydroxyglutaric aciduria, a rare autosomal recessive neurometabolic disorder resulting in moderate to severe mental retardation. L2HGDH codes for a protein that is 50 kDa in size. The L2HGDH protein contains a mitochondrial-targeting transit peptide and is localized to the mitochondrial inner membrane inside mitochondria inside the cell.
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2,6-Dihydroxypyridine is an intermediate in the degradation of nicotine by the aerobic bacterium Arthrobacter nicotinovorans. The following reaction shows the formation of the intermediate from L-nicotine of tobacco. :500px The figure represents the pathway for the degradation of L-nicotine by A. nicotinovorans to 2,6-dihydroxypyridine Another reaction of 2,6-dihydroxypyridine highlights its function as a substrate for oxygenase. One example is the enzyme monooxygenase, which oxidizes the substrate by transferring one oxygen atom of O2 to the substrate.
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An example is the 'M' series of high- speed steels such as M2, M4 and M42 as substitution for the 'T' steel series, which contain tungsten. Molybdenum can also be used as a flame-resistant coating for other metals. Although its melting point is , molybdenum rapidly oxidizes at temperatures above making it better-suited for use in vacuum environments. TZM (Mo (~99%), Ti (~0.5%), Zr (~0.08%) and some C) is a corrosion-resisting molybdenum superalloy that resists molten fluoride salts at temperatures above .
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Moisture activates the iron, and it oxidizes to form iron oxide. Typically, there must be at least 65% relative humidity in the surrounding atmosphere before the rusting process can begin. To assist in the process of oxidation, sodium chloride is added to the mixture, acting as a catalyst or activator, causing the iron powder to be able to oxidize even with relatively low humidity. As oxygen is consumed to form iron oxide the level of oxygen in the surrounding atmosphere is reduced.
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Although silica glass is naturally colorless, chemical imperfections in naturally occurring silica sometimes results in discoloration during the production process. Historically, glass makers have compensated for this by adding a chemical decolorizer. Since ancient times, one of the most common chemical decolorizers has been manganese dioxide (MnO2), which in small quantities, is an effective additive to produce clear glass. However, in large quantities, glass treated with manganese dioxide photo-oxidizes when exposed to ultra-violet sunlight over a period of years to decades.
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Iron levels above 0.3 mg/l and manganese levels above 0.5 mg/l become noticeable as an unpleasant metallic taste. Providing an aerobic hypolimnetic environment, deep-water aeration oxidizes and precipitates dissolved iron and manganese compounds, before the water is treated in a suitable facility for drinking water production. In this way further operating costs for the removal of dissolved iron and manganese compounds can be realized. The amount and mobility of iron species also influences the redox-controlled phosphorus household.
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To complete the general phenylpropanoid pathway, 4-coumarate CoA ligase (4CL) substitutes coenzyme A (CoA) at the carboxy group of p-coumarate. Entering the flavone synthesis pathway, the type III polyketide synthase enzyme chalcone synthase (CHS) uses consecutive condensations of three equivalents of malonyl CoA followed by aromatization to convert p-coumaroyl-CoA to chalcone. Chalcone isomerase (CHI) then isomerizes the product to close the pyrone ring to make naringenin. Finally, a flavanone synthase (FNS) enzyme oxidizes naringenin to apigenin.
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It oxidizes most metals and several nonmetals, including carbon, which leads to its negative charge in most organosulfur compounds, but it reduces several strong oxidants, such as oxygen and fluorine. In nature, sulfur can be found as the pure element and as sulfide and sulfate minerals. Elemental sulfur crystals are commonly sought after by mineral collectors for their brightly-colored polyhedron shapes. Being abundant in native form, sulfur was known in ancient times, mentioned for its uses in ancient Greece, China and Egypt.
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It can also not be converted to pyruvate as the pyruvate decarboxylation reaction is irreversible. Instead it condenses with oxaloacetate, to enter the citric acid cycle. During each turn of the cycle, two carbon atoms leave the cycle as CO2 in the decarboxylation reactions catalyzed by isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase. Thus each turn of the citric acid cycle oxidizes an acetyl-CoA unit while regenerating the oxaloacetate molecule with which the acetyl-CoA had originally combined to form citric acid.
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One hypothesis is that its source may be the remains of an ancient fjord that occupied the Taylor valley in the tertiary period. The ferrous iron dissolved in the water oxidizes as the water reaches the surface, turning the water blood red. The test returned a clean subglacial sample from the outflow channel from Blood Falls. Subglacial environments in Antarctica need similar protection protocols to interplanetary missions, and the probe was sterilized to these protocols using hydrogen peroxide and UV sterilization.
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Electrochemical experiments show that (+)-catechin oxidation mechanism proceeds in sequential steps, related with the catechol and resorcinol groups and the oxidation is pH-dependent. The oxidation of the catechol 3',4'-dihydroxyl electron-donating groups occurs first, at very low positive potentials, and is a reversible reaction. The hydroxyl groups of the resorcinol moiety oxidised afterwards were shown to undergo an irreversible oxidation reaction. The laccase/ABTS system oxidizes (+)-catechin to oligomeric products of which proanthocyanidin A2 is a dimer.
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It transmits oxygen from the atmosphere into water to the submerged parts of the plants, heightening the quantity of oxygen necessary to dissolve organic matters in the water to purify and improve the water quality. Oxygen discharged from the roots of Phragmites communis oxidizes soil in a resolving state, and promotes the activation and dissolution of nearby microorganisms. The wide Phragmites communis field provides an environment for the microorganism group to inhabit so that it dissolves and disperses various types of polluting substances.
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Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase (also known as catecholase, or catechol oxidase). Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut and left out), the colorless catechol oxidizes to reddish-brown melanoid pigments, derivatives of benzoquinone. The enzyme is inactivated by adding an acid, such as the citric acid contained in lemon juice. Excluding oxygen also prevents the browning reaction.
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The Sarett oxidation efficiently oxidizes primary alcohols to aldehydes without further oxidizing them to carboxylic acids. This key difference from the Jones oxidation is due to the fact that the Jones oxidation occurs in the presence of water, which adds to the alcohol following oxidation to an aldehyde. The Sarett and Collins oxidations occur in the absence of water. The Sarett oxidation also proceeds under basic conditions, which allows for the use of acid sensitive substrates, such as those containing certain protecting groups.
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The β-galactosidase assay is used frequently in genetics, molecular biology, and other life sciences. An active enzyme may be detected using artificial chromogenic substrate 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside, X-gal. β-galactosidase will cleave the glycosidic bond in X-gal and form galactose and 5-bromo-4-chloro-3-hydroxyindole which dimerizes and oxidizes to 5,5'-dibromo-4,4'-dichloro-indigo, an intense blue product that is easy to identify and quantify. It is used for example in blue white screen.
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287–288, 296; Ivanov-Emin, Misel'son & Greksa 1960 Cadmium forms Zintl phases such as LiCd, RbCd13 and CsCd13. When heated in air to a few hundred degrees, cadmium represents a toxicity hazard due to the release of cadmium vapour; when heated to its boiling point in air (just above 1000 K; 725 C; 1340 F; cf steel ~2700 K; 2425 C; 4400 F),Wanamaker & Pennington 1921, p. 56 the cadmium vapour oxidizes, 'with a reddish-yellow flame, dispersing as an aerosol of potentially lethal CdO particles.
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Paracoccus is a biochemically versatile genus, possessing a variety of metabolisms through which a wide range of diverse compounds can be degraded. Accordingly, it has the potential for a wide variety of capabilities and applications in bioremediation. The denitrifying property of Paracoccus denitrificans has been used in creating a bioreactor, in this case, a tubular gel containing two bacteria, for the removal of nitrogen from wastewater. Paracoccus denitrificans reduces nitrite to nitrogen gas while Nitrosomonas europaea oxidizes ammonia to nitrite, thus fueling the former metabolism.
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These quinones can further couple within solution producing numerous dimerizations depending upon their substituents. Fetizon's reagent oxidizes phenols to quinones which can oxidatively couple to one another Amines have been shown to oxidize in the presence of Fétizon's reagent to enamines and iminium cations that have been trapped, but can also be selected against in a compound with more easily oxidized alcohol functionalities. Fétizon's reagent can also being used to facilitate cycloaddition of a 4-hydroxy-2-furoquinilone and an olefin to form dihydrofuroquinolinones.
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In addition, these microorganisms have another enzyme, the hydrogenase, that oxidizes the H2 released as a by-product. Therefore, in this type of bacteria, the amount of hydrogen produced depends on the ratio between H2 production and consumption. In some cases, the H2 can be present in the environments because the N2-fixing bacteria can have a low quantity of hydrogenases. Instead, fermentation is performed by some strict or facultative anaerobic heterotrophic bacteria, in particular Clostridia ,that degrade organic molecules, producing hydrogen as one of the products.
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Spontaneous combustion is caused when coal oxidizes and airflow is insufficient to dissipate heat; this more commonly occurs in stockpiles and waste piles, rarely in bedded coal underground. Where coal fires occur, there is attendant air pollution from emission of smoke and noxious fumes into the atmosphere. Coal seam fires may burn underground for decades, threatening destruction of forests, homes, roadways and other valuable infrastructure. The best-known coal-seam fire may be the one which led to the permanent evacuation of Centralia, Pennsylvania, United States.
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It can also be prepared by treating bromides with non- oxidising acids like phosphoric or acetic acids. Alternatively the acid can be prepared with dilute (5.8M) sulfuric acid and potassium bromide: :H2SO4 \+ KBr → KHSO4 \+ HBr Using more concentrated sulfuric acid or allowing the reaction solution to exceed 75 °C further oxidizes HBr to bromine gas. The acid is further purified by filtering out the KHSO4 and by distilling off the water until the solution reaches an azeotrope (≈ 126 °C at 760 torr). The yield is approximately 85%.
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PROX is an acronym for PReferential OXidation, and refers to the preferential oxidation of a carbon monoxide in a gas mixture by a catalyst. It is intended to remove trace amounts of CO from H2/CO/CO2 mixtures produced by steam reforming and water-gas shift. An ideal PROX catalyst preferentially oxidizes carbon monoxide (CO) using a heterogeneous catalyst placed upon a ceramic support. Catalysts include metals such as platinum, platinum/iron, platinum/ruthenium, gold nanoparticles as well as novel copper oxide/ceramic conglomerate catalysts.
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Cells in the central nervous system (astrocytes) include MAO-B that oxidizes MPTP to 1-methyl-4-phenylpyridinium (MPP+), which is toxic. MPP+ eventually travels to the extracellular fluid by a dopamine transporter, which ultimately causes the Parkinson's symptoms. However, competitive inhibition of the MAO-B enzyme or the dopamine transporter protects against the oxidation of MPTP to MPP+. A few compounds have been tested for their ability to inhibit oxidation of MPTP to MPP+ including methylene blue, 5-nitroindazole, norharman, 9-methylnorharman, and menadione.
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Early chemosynthetic organisms likely produced methane, an important trap for molecular oxygen, since methane readily oxidizes to carbon dioxide (CO2) and water in the presence of UV radiation. Modern methanogens require nickel as an enzyme cofactor. As the Earth's crust cooled and the supply of volcanic nickel dwindled, oxygen-producing algae began to out- perform methane producers, and the oxygen percentage of the atmosphere steadily increased. From 2.7 to 2.4 billion years ago, the rate of deposition of nickel declined steadily from a level 400 times today's.
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There have been multiple studies to find a replacement oxidant that is less expensive than [PtIVCl6]2− or a method to regenerate [PtIVCl6]2−. It would be most advantageous to develop an electron train which would use oxygen as the ultimate oxidant. It is important that the oxidant preferentially oxidizes the PtII-CH2R species over the initial PtII species since PtIV complexes will not electrophilically activate a C-H bond of the alkane (although PtIV complexes electrophilically substitute hydrogens in aromatics - see refs. [1] and [2] ).
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Chlorine replaces hydrogen on the aromatic rings of lignin via aromatic substitution, oxidizes pendant groups to carboxylic acids and adds across carbon carbon double bonds in the lignin sidechains. Chlorine also attacks cellulose, but this reaction occurs predominantly at pH 7, where un-ionized hypochlorous acid, HClO, is the main chlorine species in solution. To avoid excessive cellulose degradation, chlorination is carried out at pH <1.5. : Cl2 \+ H2O ⇌ H+ \+ Cl− \+ HClO At pH >8 the dominant species is hypochlorite, ClO−, which is also useful for lignin removal.
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Two main processes govern changes in the atmosphere: plants use carbon dioxide from the atmosphere, releasing oxygen and the breakdown of pyrite and volcanic eruptions release sulfur into the atmosphere, which oxidizes and hence reduces the amount of oxygen in the atmosphere. However, volcanic eruptions also release carbon dioxide, which plants can convert to oxygen. The exact cause of the variation of the amount of oxygen in the atmosphere is not known. Periods with much oxygen in the atmosphere are associated with rapid development of animals.
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Lunar and Planetary Science XXXVII (2006). 1193.pdf-1193.pdf. However, a recent study indicates that to match the observations of methane, there must be something that quickly destroys the gas, otherwise it would be spread all through the atmosphere instead of being concentrated in just a few locations. There may be something in the soil that oxidizes the gas before it has a chance to spread. If this is so, that same chemical would destroy organic compounds, thus life would be very difficult on Mars.
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Two reaction mechanisms have been proposed, in one of which there is a direct interaction between the tungsten atom and the C≡C triple bond. Although a tungsten-containing xanthine dehydrogenase from bacteria has been found to contain tungsten-molydopterin and also non-protein bound selenium, a tungsten-selenium molybdopterin complex has not been definitively described. In soil, tungsten metal oxidizes to the tungstate anion. It can be selectively or non-selectively imported by some prokaryotic organisms and may substitute for molybdate in certain enzymes.
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In the Olin Raschig process, chlorine-based oxidants oxidize ammonia without the presence of a ketone. In the peroxide process, hydrogen peroxide oxidizes ammonia in the presence of a ketone. Hydrazine is produced in the Olin-Raschig process from sodium hypochlorite (the active ingredient in many bleaches) and ammonia, a process announced in 1907. This method relies on the reaction of monochloramine with ammonia to create the nitrogen–nitrogen single bond as well as a hydrogen chloride byproduct: : NH2Cl + NH3 -> H2NNH2 + HCl Related to the Raschig process, urea can be oxidized instead of ammonia.
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An improvement to the methanizer is the Polyarc reactor, which is a sequential reactor that oxidizes compounds before reducing them to methane. This method can be used to improve the response of the FID and allow for the detection of many more carbon-containing compounds. The complete conversion of compounds to methane and the now equivalent response in the detector also eliminates the need for calibrations and standards because response factors are all equivalent to those of methane. This allows for the rapid analysis of complex mixtures that contain molecules where standards are not available.
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Created in 1991 by Brooklyn born artist Beverly Pepper and carved from an abandoned freeway corridor, the piece has been described by the Milwaukee Journal Sentinel as "slicing into the sky like a tool left behind by Paul Bunyan." It is made from Cor-ten, a favorite among outdoor artists, which naturally oxidizes while maintaining a deep rustlike appearance. Cleopatra's Wedge came to Milwaukee by way of Chicago's Navy Pier. Before that it was exhibited in New York's Battery Park, Florence, Paris, and other places around the world.
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After production in the upper atmosphere, the carbon-14 atoms react rapidly to form mostly (about 93%) 14CO (carbon monoxide), which subsequently oxidizes at a slower rate to form 14CO2, radioactive carbon dioxide. The gas mixes rapidly and becomes evenly distributed throughout the atmosphere (the mixing timescale in the order of weeks). Carbon dioxide also dissolves in water and thus permeates the oceans, but at a slower rate. The atmospheric half-life for removal of 14CO2 has been estimated to be roughly 12 to 16 years in the northern hemisphere.
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This function is part of the Respiratory chain. Initially, SDHA oxidizes succinate via deprotonation at the FAD binding site, forming FADH2 and leaving fumarate, loosely bound to the active site, free to exit the protein. Electrons from FADH2 are transferred to the SDHB subunit iron clusters [2Fe-2S],[4Fe-4S],[3Fe-4S] and tunnel along the [Fe-S] relay until they reach the [3Fe-4S] iron sulfur cluster. The electrons are then transferred to an awaiting ubiquinone molecule at the Q pool active site in the SDHC/SDHD dimer.
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Regulation of oxidation response in bacteria involving OxyR and SoxRS regulons The transcriptional factor OxyR regulates the expression of OxyR regulon. H2O2 oxidizes the transcriptional factor by forming an intramolecular disulfide bond. The oxidized form of this factor specifically binds to the promoters of constituent genes of OxyR regulon, including katG (hydroperoxidase-catalase HPІ), gorA (glutathione reductase), grxA (glutaredoxin 1), trxC(thioredoxin 2), ahpCF (alkyl hydroperoxide reductase), dps (nonspecific DNA binding protein) and oxyS (a small regulatory RNA). Reduced OxyR provides autorepression by binding only to the oxyR promoter.
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Vegetable peroxidase and bacterial enzymes, including an Escherichia coli peroxidase, may also cause false-positive reactions. Therefore, sediments containing bacteria should be checked closely for the presence of red blood cells. Traditionally, ascorbic acid (vitamin C) has been associated with false-negative reagent strip reactions for blood. Both Multistix and Chemstrip have modified their reagent strips to reduce this interference to very high levels of ascorbic acid, and Chemstrip overlays the reagent pad with an iodate-impregnated mesh that oxidizes the ascorbic acid prior to its reaching the reaction pad.
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Reaktionen mit Carbamidperoxid It converts thiols selectively to disulfides, secondary alcohols to ketones, sulfides to sulfoxides and sulfones, nitriles to amides, N-heterocycles to amine oxides. Reaktionen von Methoxyphenolen mit UHP Hydroxybenzaldehyde are converted to dihydroxybenzenes (Dakin reaction) and gives under suitable conditions the corresponding benzoic acids. Baeyer-Villiger-Oxidation mit UHP It oxidizes ketones to esters, in particular cyclic ketones, such as substituted cyclohexanones or cyclobutanones to give lactones (Baeyer-Villiger oxidation). The epoxidation of various alkenes in the presence of benzonitrile yields oxiranes in yields of 79 to 96%.
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The iron oxidizes, and the copper ions are reduced through the transfer of electrons. The reaction is spontaneous because copper is higher on the galvanic series than iron. : Cu2+(aq) + Fe(s) → Cu(s) + Fe2+(aq) This was a historically useful process for the production of copper, where the precipitated solid copper metal was recovered as flakes or powder on the surface of scrap iron."A study on the optimum conditions of the cementation of copper in chlorination solution of chalcopyrite concentrate by iron scraps," by Hakan TEMUR, Ahmet YARTAŞI and M. Muhtar KOCAKERIM.
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In the liver, the enzyme alcohol dehydrogenase oxidizes ethanol into acetaldehyde, which is then further oxidized into harmless acetic acid by acetaldehyde dehydrogenase. These two oxidation reactions are coupled with the reduction of NAD+ to NADH. In the brain, the enzyme catalase is primarily responsible for oxidizing ethanol to acetaldehyde, and alcohol dehydrogenase plays a minor role. The last steps of alcoholic fermentation in bacteria, plants, and yeast involve the conversion of pyruvate into acetaldehyde and carbon dioxide by the enzyme pyruvate decarboxylase, followed by the conversion of acetaldehyde into ethanol.
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Ozone is very unstable and reactive and oxidizes most organic material it comes in contact with, thereby destroying many pathogenic microorganisms. Ozone is considered to be safer than chlorine because, unlike chlorine which has to be stored on site (highly poisonous in the event of an accidental release), ozone is generated on-site as needed from the oxygen in the ambient air. Ozonation also produces fewer disinfection by-products than chlorination. A disadvantage of ozone disinfection is the high cost of the ozone generation equipment and the requirements for special operators.
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Electrocoagulation ("electro", meaning to apply an electrical charge to water, and "coagulation", meaning the process of changing the particle surface charge, allowing suspended matter to form an agglomeration) is an advanced and economical water treatment technology. It effectively removes suspended solids to sub-micrometre levels, breaks emulsions such as oil and grease or latex, and oxidizes and eradicates heavy metals from water without the use of filters or the addition of separation chemicals Noling, Calvin (2004-07-01). "New Electrocoagulation System Addresses Challenges of Industrial Storm, Wash Water." WaterWorld.
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Instead the acetyl-CoA produced by the beta-oxidation of fatty acids condenses with oxaloacetate, to enter the citric acid cycle. During each turn of the cycle, two carbon atoms leave the cycle as CO2 in the decarboxylation reactions catalyzed by isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase. Thus each turn of the citric acid cycle oxidizes an acetyl-CoA unit while regenerating the oxaloacetate molecule with which the acetyl-CoA had originally combined to form citric acid. The decarboxylation reactions occur before malate is formed in the cycle.
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Diagram of Tight junction. Occludin is an enzyme (EC 1.6) that oxidizes NADH. It was first identified in epithelial cells as a 65 kDa integral plasma- membrane protein localized at the tight junctions, and together with Claudins, and zonula occludens-1 (ZO-1), has been considered a staple of tight junctions. Although it was originally shown to regulate the formation, maintenance, and function of tight junctions, its precise mechanism of action remained elusive, and most of its actions were initially attributed to conformational changes following its selective phosphorylation.
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Bunsen burner: leftmost: reducing flame, rightmost: oxidizing flame Oxygen rich butane torch flame Fuel rich butane torch flame In various burners, the oxidizing flame is the flame produced with an excessive amount of oxygen. When the amount of oxygen increases, the flame shortens, its color darkens, and it hisses and roars."The Anatomy of a Flame", in: "Jewelry concepts and technology", by Oppi Untracht, 1983, With some exceptions (e.g., platinum soldering in jewelry), the oxidizing flame is usually undesirable for welding and soldering, since, as its name suggests, it oxidizes the metal's surface.
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Water contains hydrogen in the oxidation state +1 and oxygen in the oxidation state −2. It oxidizes chemicals such as hydrides, alkali metals, and some alkaline earth metals. One example of an alkali metal reacting with water is: :2 Na + 2 → + 2 + 2 Some other reactive metals, such as aluminum and beryllium, are oxidized by water as well, but their oxides adhere to the metal and form a passive protective layer. Note that the rusting of iron is a reaction between iron and oxygen that is dissolved in water, not between iron and water.
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This compound has idealized D3 symmetry. Six oxygen atoms surround the central ruthenium atom in an octahedral arrangement. The average Ru-O bond length in Ru(acac)3 is 2.00 Å. Because Ru(acac)3 is low spin, there is one unpaired d electron, causing this compound to be paramagnetic. Ru(acac)3 has a magnetic susceptibility, χM, of 3.032×10−6 cm3/mol with an effective magnetic moment, μeff, of 1.66 μB. As a solution in DMF, the compound oxidizes at 0.593 and reduces at -1.223 V vs the ferrocene/ferrocenium couple.
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Initiation of DNA demethylation at a CpG site. In adult somatic cells DNA methylation typically occurs in the context of CpG dinucleotides (CpG sites), forming 5-methylcytosine-pG, or 5mCpG. Reactive oxygen species (ROS) may attack guanine at the dinucleotide site, forming 8-hydroxy-2'-deoxyguanosine (8-OHdG), and resulting in a 5mCp-8-OHdG dinucleotide site. The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG.
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A tetrose diphosphate molecule, D-threose 2,4-diphosphate, was discovered to be an inhibitor of glyceraldehyde 3-phosphate dehydrogenase. Glyceraldehyde 3-phosphate dehydrogenase is the sixth enzyme used in the glycolysis pathway, and its function is to convert glyceraldehyde 3-phosphate into 1,3-bisphosphoglycerate. This tetrose diphosphate molecule inhibits the G3P dehydrogenase from performing catalysis because it oxidizes the enzyme by binding to it at the active site. When tetrose diphosphate is bound to the enzyme, the active site of the enzyme is blocked; therefore phosphorolysis of G3P is unable to occur.
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The uses of KI include as a nutritional supplement in animal feeds and also the human diet. For the latter, it is the most common additive used to "iodize" table salt (a public health measure to prevent iodine deficiency in populations that get little seafood). The oxidation of iodide causes slow loss of iodine content from iodised salts that are exposed to excess air. The alkali metal iodide salt, over time and exposure to excess oxygen and carbon dioxide, slowly oxidizes to metal carbonate and elemental iodine, which then evaporates.
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Formation of pretetramid allows for one of the most important intermediates en route to the biosynthesis of oxytetracycline; this is the generation of anhydrotetracycline. Anhydrotetracycline contains the first functionalized A ring in this biosynthetic pathway. After the formation of anhydrotetracycline, ATC monooxygenase (OxyS) oxidizes the C-6 position in an enantioselective manner in the presence of the cofactor NADPH and atmospheric oxygen to produce 5a,11a-dehydrotetracycline. Next, a hydroxylation occurs at the C-5 position of 5a,11a-dehydrotetracycline via the oxygenase encoded as OxyE in the oxytetracycline gene cluster.
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Initiation of DNA demethylation at a CpG site. In adult somatic cells DNA methylation typically occurs in the context of CpG dinucleotides (CpG sites), forming 5-methylcytosine-pG, or 5mCpG. Reactive oxygen species (ROS) may attack guanine at the dinucleotide site, forming 8-hydroxy-2'-deoxyguanosine (8-OHdG), and resulting in a 5mCp-8-OHdG dinucleotide site. The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG.
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Radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, becoming black in color. All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1601 years and decays into radon gas. Because of such instability, radium is luminescent, glowing a faint blue. Radium, in the form of radium chloride, was discovered by Marie Skłodowska-Curie and Pierre Curie in 1898.
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Early linoleum at Tyntesfield Linoleum was invented by Englishman Frederick Walton. In 1855, Walton happened to notice the rubbery, flexible skin of solidified linseed oil (linoxyn) that had formed on a can of oil-based paint and thought that it might form a substitute for India rubber. Raw linseed oil oxidizes very slowly, but Walton accelerated the process by heating it with lead acetate and zinc sulfate. This made the oil form a resinous mass into which lengths of cheap cotton cloth were dipped until a thick coating formed.
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It oxidizes succinate to fumarate and reduces ubiquinone. As this reaction releases less energy than the oxidation of NADH, complex II does not transport protons across the membrane and does not contribute to the proton gradient. In some eukaryotes, such as the parasitic worm Ascaris suum, an enzyme similar to complex II, fumarate reductase (menaquinol:fumarate oxidoreductase, or QFR), operates in reverse to oxidize ubiquinol and reduce fumarate. This allows the worm to survive in the anaerobic environment of the large intestine, carrying out anaerobic oxidative phosphorylation with fumarate as the electron acceptor.
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Initiation of DNA demethylation at a CpG site. In adult somatic cells DNA methylation typically occurs in the context of CpG dinucleotides (CpG sites), forming 5-methylcytosine-pG, or 5mCpG. Reactive oxygen species (ROS) may attack guanine at the dinucleotide site, forming 8-hydroxy-2'-deoxyguanosine (8-OHdG), and resulting in a 5mCp-8-OHdG dinucleotide site. The base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1 and TET1 oxidizes the 5mC adjacent to the 8-OHdG.
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Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body. While many drugs are deactivated by CYP3A4, there are also some drugs which are activated by the enzyme. Some substances, such as grapefruit juice and some drugs, interfere with the action of CYP3A4. These substances will therefore either amplify or weaken the action of those drugs that are modified by CYP3A4.
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Firing the pellet oxidizes the magnetite (Fe3O4) to hematite (Fe2O3), an exothermic reaction that reduces the cost of pelletizing the concentrate. E. W. Davis of the University of Minnesota Mines Experiment Station is credited with developing the pelletizing process. Since the commercial development of this process in the Lake Superior region in the 1950s, the term "taconite" has been used globally to refer to iron ores amenable to upgrading by similar processes. Major producers of iron ore pellets from taconite in North America include Iron Ore Company of Canada, Cliffs Natural Resources, Inc.
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In R. sphaeroides, DMSOR is a single-subunit, water- soluble protein that requires no additional cofactors beyond pterin. In E. coli, DMSOR is embedded within the membrane and has three unique subunits, one of which includes the characteristic pterin cofactor, another which contains four 4Fe:4S clusters, and a final transmembrane subunit that binds and oxidizes menaquinol. The transfer of an e- from menaquinol to the 4Fe:4S clusters and finally to the pterin-Mo active site generates a proton gradient used for ATP generation. DMSOR regulated predominantly at a transcriptional level.
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Stoichiometric equation representing the metabolism of an aldehyde substrate by ALDH3A1 using NADP+ as a cofactor Electronic excitations of alkene and aromatic functional groups allow certain nucleic acids, proteins, fatty acids and organic molecules to absorb ultraviolet radiation (UVR). Moderate UVR exposure oxidizes specific proteins that eventually serve as signaling agents for an array of metabolic and inflammatory pathways. Overexposure to UVR, on the other hand, can be detrimental to the tissue. In the presence of molecular oxygen, UVR leads to the formation of reactive oxygen species (ROS) that are implicated in many degradation pathways.
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ALDH3A1's absorption of UVR oxidizes several key amino acid residues, leading to conformational changes that convert the alpha and beta sheets into random coils. These conformational changes ultimately relieve the dimer structure. This loss of secondary and tertiary structure leads to protein aggregation and complete loss of enzymatic activity. Peptide mapping and spectroscopic experiments reveal that the loss of activity is not a result of Cys244 oxidation (which, together with the active site, remains intact during photo-excitation), but instead, due to the degradation of other key amino residues (most notably methionine and tryptophan).
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Box wine can stay acceptably fresh for up to a month after opening because the bladder collapses as wine is dispensed, limiting contact with air and, thus, slowing the rate of oxidation. In contrast, bottled wine oxidizes more rapidly after opening because of the increasing ratio of air to wine as the contents are dispensed; it can degrade considerably in a few days. Cans are one of the fastest-growing forms of alternative wine packaging on the market. Environmental considerations of wine packaging reveal benefits and drawbacks of both bottled and box wines.
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A. nitrofigilis is a nitrogen-fixing bacterium isolated from the roots of the salt marsh plant Spartina alterniflora. A. sulfidicus is an obligate microaerophile that oxidizes sulfides and is an autotrophic producer of filamentous sulfur. Large populations of this bacterium produce mats of this solid, white sulfur filament. These mats are useful in anchoring the bacteria to rocky surfaces in the face of flowing subsurface hydrothermal fluids, as well as providing important carpeting around hydrothermal vents that attracts other animals to that site and encourages them to settle and grow.
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Like other plutonium-producing reactors, conserving neutrons is a key element of the design. In magnox, the neutrons are moderated in large blocks of graphite. The efficiency of graphite as a moderator allows the Magnox to run using natural uranium fuel, in contrast with the more common commercial light-water reactor which requires slightly enriched uranium. Graphite oxidizes readily in air, so the core is cooled with CO2, which is then pumped into a heat exchanger to generate steam to drive conventional steam turbine equipment for power production.
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The reactive layer contains a polymer resin that acts as a carrier for a suitable leuco dye, which, upon contact with atmospheric oxygen, oxidizes to form an opaque or semi-opaque material. Some of the dyes used are methylene blue, prussian blue, brilliant cresyl blue, Toluidine Blue O, Basic Blue 3, Methylene Green, Taylor's Blue, Janus Green B, Meldola's Blue, Thionin, Nile Blue, and Celestine Blue. The leuco dye is prepared by chemical reduction using a suitable reducing agent. The method commercially used by Flexplay and SpectraDisc employs methylene blue reduced by sodium dithionite.
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Manual gas control valve Griddles with manual controls require constant attention by an operator to control the temperature of the griddle plate. Without food products to remove the heat from a griddle surface, the unregulated heat source can cause the plate surface temperature to rise continuously until it levels out at temperatures well beyond those normally used for cooking (over ). At these temperatures the griddle plate material may take on a bluish tint as the surface of the carbon steel plate oxidizes. Manual controls are not typically used on electric griddles.
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A problem with using reverberatory furnaces for cupellation is that the zinc oxidizes first, forming a crust across the top of the molten material. This crust prevents the penetration of oxygen to the rest of the material, and so it has to be manually broken up and removed using a rabble bar. This is both labor-intensive and also results in the loss of some of the silver. Similarly, the oxidized lead slag has to be removed when it forms to maintain the operation, and its removal also results in loss of silver.
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Damage repair is the conversion of a damaged metabolite back to its original state via one or more enzymatic reactions; the concept is similar to DNA repair and protein repair. For example, the promiscuous activity of malate dehydrogenase causes reduction of alpha-ketoglutarate to L-2-hydroxyglutarate. This compound is a dead-end metabolite and is not a substrate for any other enzyme in central metabolism, and its accumulation in humans causes L-2-Hydroxyglutaric aciduria. The repair enzyme L-2-hydroxyglutarate dehydrogenase oxidizes L-2-hydroxyglutarate back to alpha-ketoglutarate, thus repairing this metabolite.
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When Nomex material is exposed to flame, instead of burning or melting it develops a carbon char. The char thickens the section of fiber exposed to the flame, preventing the spread of the fire to the rest of the suit and inhibiting the transfer of heat to the wearer of the garment. CarbonX is a different fabric for fire suits made of oxidized polyacrylonitrile (a precursor to carbon fiber). It is created by heating material until it oxidizes and chars, with the finished product able to last for two minutes exposed to fire.
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Plutonium, like most metals, has a bright silvery appearance at first, much like nickel, but it oxidizes very quickly to a dull gray, although yellow and olive green are also reported. (public domain text) At room temperature plutonium is in its α (alpha) form. This, the most common structural form of the element (allotrope), is about as hard and brittle as gray cast iron unless it is alloyed with other metals to make it soft and ductile. Unlike most metals, it is not a good conductor of heat or electricity.
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2011, 13, 2212-2215 This enzyme was shown to be responsible for an oxidative transformation step (namely the 10-hydroxy dehydrogenation) to an intermediate that eventually leads to the ultimate product of the pathway, suggested to be tirandamycin B. Through a study of the metabolites produced after gene inactivation of the flavin-dependent enzyme and an in vitro characterization of the activity of the enzyme, they were able to conclude that the enzyme oxidizes tirandamycin E or F to tirandamycin A or D (See Figure 3). In the same year, Carlson et al.
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Three isoforms are known for the NOS enzyme: endothelial (eNOS), neuronal (nNOS), and inducible (iNOS) - each with separate functions. The neuronal enzyme (NOS-1) and the endothelial isoform (NOS-3) are calcium-dependent and produce low levels of this gas as a cell signaling molecule. The inducible isoform (NOS-2) is calcium-independent and produces large amounts of gas that can be cytotoxic. NOS oxidizes the guanidine group of L-arginine in a process that consumes five electrons and results in the formation of NO with stoichiometric formation of L-citrulline.
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Gently rubbing the alloy into the surface may help induce wetting. However, this observation of "wetting by rubbing into glass surface" has created a widely spread misconception that the gallium-based liquid metals wet glass surfaces, as if the liquid breaks free of the oxide skin and wets the surface. The reality is the opposite: the oxide makes the liquid wet the glass. In more details: as the liquid is rubbed into and spread onto the glass surface, the liquid oxidizes and coats the glass with a thin layer of oxide (solid) residues, on which the liquid metal wets.
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A stagnohumic gley soil in a forest plantation in mid-Wales, U.K. The organic-rich topsoil is over a grey and orange mottled subsoil developed in glacial till ("boulder clay") They exhibit a greenish- blue-grey soil color due to anoxic wetland conditions. On exposure, as the iron in the soil oxidizes colors are transformed to a mottled pattern of reddish, yellow or orange patches. During soil formation (gleying), the oxygen supply in the soil profile is restricted due to soil moisture at saturation. Anaerobic micro-organisms support cellular respiration by using alternatives to free oxygen as electron acceptors to support cellular respiration.
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The compound is prepared in a tube furnace by the reaction of bromine vapor and chromium powder at 1000 °C. It is purified by extracting with absolute diethyl ether to remove any CrBr2, and is subsequently washed with absolute diethyl ether and absolute ethanol. Analogous to the behavior of related chromium(III) halides, the tribromide dissolves in water to give CrBr3(H2O)3 only upon the addition of catalytic amounts of a reducing agent, which generates CrBr2. The reducing agent generates chromous bromide on the surface of the solid, which dissolves and re-oxidizes to Cr(III).
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As the zirconium melts it oxidizes and blends with the now molten zirconium oxide, a conductor, and is heated by radio frequency induction. When the zirconium oxide is melted on the inside (but not completely, since the outside needs to remain solid) the amplitude of the RF induction coil is gradually reduced and crystals form as the material cools. Normally this would form a monoclinic crystal system of zirconium oxide. In order to maintain a cubic crystal system a stabilizer is added, magnesium oxide, calcium oxide or yttrium oxide as well as any material to color the crystal.
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The dinuclear ferroxidase centers are located at the interfaces between subunits related by 2-fold symmetry axes. Fe(II) is sequestered and stored in the form of Fe(III) oxyhydroxide mineral, which can be released after reduction. In the mineral iron core up to 500 Fe(III) can be deposited. One hydrogen peroxide oxidizes two Fe2+ ions, which prevents hydroxyl radical production by the Fenton reaction (reaction I): 2 Fe2+ \+ H2O2 \+ 2 H+ = 2 Fe3+ \+ 2 H2O Dps also protects the cell from UV and gamma ray irradiation, iron and copper toxicity, thermal stress and acid and base shocks.
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The nitric acid and peroxide mixture oxidizes and dissolves any impurities on the inner surface of the container, and the deionized water rinses away the acid and oxidized impurities.Aluminum Passivation Generally, there are two main ways to passivate aluminium alloys (not counting plating, painting, and other barrier coatings): chromate conversion coating and anodizing. Alclading, which metallurgically bonds thin layers of pure aluminium or alloy to different base aluminium alloy, is not strictly passivation of the base alloy. However, the aluminium layer clad on is designed to spontaneously develop the oxide layer and thus protect the base alloy.
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' These additives often include wetting agents such as alkyl aryl sulfonates, but the exact nature of these additives are not known for commercial drain cleaners, as they are regarded as the trade secrets that make each drain cleaner unique to its brand. The aluminum granules that are included in the solid caustic drain cleaner is an aluminum oxide that breaks down and re-oxidizes to release hydrogen gas. The components of this reaction are shown below. Because the release of hydrogen gas is overall an exothermic reaction, the extra heat released helps to break down the greases, oils, etc.
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In nature, methional is a thermally-induced volatile flavor compound. For instance, the heat-initiated Maillard reaction of reducing sugars and amino acids forms the initial basis of methional's composition. The formation of methional stems from the interaction of α-dicarbonyl compounds (intermediate products in the Maillard reaction) with methionine (Met) by the Strecker degradation reaction: :CH3SCH2CH2(NH2)CHCO2H + O → CH3SCH2CH2(HN=)CCO2H + H2O :CH3SCH2CH2(HN=)CCO2H + H2O → CH3SCH2CH2CHO + NH3 \+ CO2 Methional easily degrades into methanethiol, which then oxidizes into dimethyl disulfide. Dimethyl disulfide is partly responsible for the "reactive sulfur" that contributes to the taste of potatoes.
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Propylene glycol Propylene glycol is considerably less toxic than ethylene glycol and may be labeled as "non-toxic antifreeze". It is used as antifreeze where ethylene glycol would be inappropriate, such as in food-processing systems or in water pipes in homes where incidental ingestion may be possible. For example, the U.S. FDA allows propylene glycol to be added to a large number of processed foods, including ice cream, frozen custard, salad dressings, and baked goods, and it is commonly used as the main ingredient in the "e-liquid" used in electronic cigarettes. Propylene glycol oxidizes to lactic acid.
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Covellite from the Black Forest, Germany Covellite's occurrence is widespread around the world, with a significant number of localities in Central Europe, China, Australia, Western United States, and Argentina. Many are found close to orogenic belts, where orographic precipitation often plays a role in weathering. An example of primary mineral formation is in hydrothermal veins at depths of 1,150 m found in Silver Bow County, Montana. As a secondary mineral, covellite also forms as descending surface water in the supergene enrichment zone oxidizes and redeposits covellite on hypogene sulfides (pyrite and chalcopyrite) at the same locality.
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SDHD forms part of the transmembrane protein dimer with SDHC that anchors Complex II to the inner mitochondrial membrane. The SDHC/SDHD dimer provides binding sites for ubiquinone and water during electron transport at Complex II. Initially, SDHA oxidizes succinate via deprotonation at the FAD binding site, leaving fumarate, loosely bound to the active site, free to exit the protein. The electrons derived from succinate tunnel along the [Fe-S] relay in the SDHB subunit until they reach the [3Fe-4S] iron–sulfur cluster. The electrons are then transferred to an awaiting ubiquinone molecule at the active site in the SDHC/SDHD dimer.
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AP sites and T:G mismatches are then repaired by base excision repair (BER) enzymes to yield cytosine (Cyt). The first figure in this section shows a CpG site where the cytosine is methylated to form 5-methylcytosine (5mC) and the guanine is oxidized to form 8-oxo-2'-deoxyguanosine (in the figure this is shown in the tautomeric form 8-OHdG). When this structure is formed, the base excision repair enzyme OGG1 targets 8-OHdG and binds to the lesion without immediate excision. OGG1, present at a 5mCp-8-OHdG site recruits TET1, and TET1 oxidizes the 5mC adjacent to the 8-OHdG.
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The value of E⦵(Ce4+/Ce3+) varies widely depending on conditions due to the relative ease of complexation and hydrolysis with various anions, though +1.72 V is a usually representative value; that for E⦵(Ce3+/Ce) is −2.34 V. Cerium is the only lanthanide which has important aqueous and coordination chemistry in the +4 oxidation state.Greenwood and Earnshaw, pp. 1244–8 Due to ligand-to-metal charge transfer, aqueous cerium(IV) ions are orange-yellow. Aqueous cerium(IV) is metastable in water and is a strong oxidising agent that oxidizes hydrochloric acid to give chlorine gas.
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Sodium glucuronate can be produced by the direct oxidation of starch with concentrated nitric acid. In this preparation the low availability of water keeps the starch polymers from hydrolyzing and only oxidizes the free hydroxyls, in much the same way that nitrogen dioxide would oxidize the starch. Once this reaction is complete, and the starch/nitric acid mix turns clear (after giving off nitrogen dioxide gas), the solution can be diluted, and hydrolyzed with another mineral acid. Then the oxidation is slowly quenched with sodium hydroxide (or sodium bicarbonate), forming sodium glucuronate, which can be crystallized out of solution.
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Although there are case reports of life threatening toxicity involving unusually large amounts, typical inhaled doses of amyl nitrite is considered relatively safe. Accordingly, liquid amyl nitrite is highly toxic when ingested because of the unsafely high concentration it effects in blood. Regardless of the form or route of administration, acute toxicity principally results when the nitrite oxidizes a significant proportion of haemoglobin in the blood without oxygen, forming methaemoglobin, which cannot carry oxygen. Severe poisoning cases will progress to methaemoglobemia, characterized by a blue-brown discoloration under the skin which could be mistaken for cyanosis.
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Cysteine residues play a valuable role by crosslinking proteins, which increases the rigidity of proteins and also functions to confer proteolytic resistance (since protein export is a costly process, minimizing its necessity is advantageous). Inside the cell, disulfide bridges between cysteine residues within a polypeptide support the protein's tertiary structure. Insulin is an example of a protein with cystine crosslinking, wherein two separate peptide chains are connected by a pair of disulfide bonds. Protein disulfide isomerases catalyze the proper formation of disulfide bonds; the cell transfers dehydroascorbic acid to the endoplasmic reticulum, which oxidizes the environment.
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This reaction also consumes serine and pyridoxal phosphate (PLP; vitamin B6) and produces glycine and pyridoxal. A second enzyme, methylenetetrahydrofolate dehydrogenase (MTHFD2) oxidizes 5,10-methylenetetrahydrofolate to an iminium cation which in turn is hydrolyzed to produce 5-formyl-THF and 10-formyl-THF. This series of reactions using the β-carbon atom of serine as the carbon source provide the largest part of the one-carbon units available to the cell. Alternative carbon sources include formate which by the catalytic action of formate–tetrahydrofolate ligase add a 1C unit to THF to yield 10-formyl-THF.
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It is produced by the reaction of calcium oxide, calcium carbonate with hydrobromic acid or the reaction of calcium metal with elemental bromine.Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders “Bromine Compounds” Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. It adopts the rutile structure, featuring octahedral Ca centres bound to six bromide anions, which also bridge to other Ca centres. When strongly heated in air, calcium bromide will react with oxygen to produce calcium oxide and bromine: :2 CaBr2 \+ O2 → 2 CaO + 2 Br2 In this reaction the oxygen oxidizes the bromide to bromine.
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The Maine Legislature's Legislative Council has authorized the replacement of the copper sheath of the dome, which is long past its intended 75-year lifespan when it was installed in 1909–1910. The copper was pockmarked with hail damage and corrosion, with some holes in it as large as a dime. The eight-month project commenced in March 2014 and completed in October. The dome appears exactly the same as prior to renovations, with the exception of the color; it will appear brown for approximately 35 years until the copper oxidizes to a green once again.
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If the pH is over seven then consider soil remediation that will lower the pH toward the 6.5 - 7 range. Remediation includes: i) adding compost, manure, peat or similar organic matter (warning. Some retail blends of manure and compost have pH in the range 7 - 8 because of added lime. Read the MSDS if available.) ii) applying Ammonium Sulphate as a Nitrogen fertilizer (acidifying fertilizer due to decomposition of ammonium ion to nitrate in the soil and root zone) iii) applying elemental Sulphur to the soil (oxidizes over the course of months to produce sulphate/sulphite and lower pH).
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In colour and chromogenic black-and-white photography, a similar development process is used except that the reduction of silver simultaneously oxidizes the paraphenylene colour developing agent which then takes part in the production of dye-stuffs in the emulsion by reacting with the appropriate couplers. There are three distinct processes used here. The C-41 process is used for almost all colour negative films and in this process dye couplers in the emulsion react with the oxidized colour developing agent in the developer solution to generate the visible dyes. An almost identical process is then used to produce colour prints from films.
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A diagram of the Bessemer converter. Air blown through holes in the converter bottom creates a violent reaction in the molten pig iron that oxidizes the excess carbon, converting the pig iron to pure iron or steel, depending on the residual carbon. The Bessemer process, invented by Sir Henry Bessemer, allowed the mass-production of steel, increasing the scale and speed of production of this vital material, and decreasing the labor requirements. The key principle was the removal of excess carbon and other impurities from pig iron by oxidation with air blown through the molten iron.
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Ytterbium is a soft, malleable and ductile chemical element that displays a bright silvery luster when pure. It is a rare earth element, and it is readily dissolved by the strong mineral acids. It reacts slowly with cold water and it oxidizes slowly in air. Ytterbium has three allotropes labeled by the Greek letters alpha, beta and gamma; their transformation temperatures are −13 °C and 795 °C, although the exact transformation temperature depends on the pressure and stress. The beta allotrope (6.966 g/cm3) exists at room temperature, and it has a face-centered cubic crystal structure.
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Primates. In humans and higher primates, uric acid (actually hydrogen urate ion) is the final oxidation (breakdown) product of purine metabolism and is excreted in urine, whereas in most other mammals, the enzyme uricase further oxidizes uric acid to allantoin. The loss of uricase in higher primates parallels the similar loss of the ability to synthesize ascorbic acid, leading to the suggestion that urate may partially substitute for ascorbate in such species. Both uric acid and ascorbic acid are strong reducing agents (electron donors) and potent antioxidants. In humans, over half the antioxidant capacity of blood plasma comes from hydrogen urate ion. Humans.
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The strong oxidative potential of the positive holes oxidizes water to create hydroxyl radicals. It can also oxidize oxygen or organic materials directly. Hence, in addition to its use as a pigment, titanium dioxide can be added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing, and anti- fouling properties, and is used as a hydrolysis catalyst. It is also used in dye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell). The photocatalytic properties of nanosized titanium dioxide were discovered by Akira Fujishima in 1967 and published in 1972.
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The regression process theory was formulated by H. Luppo-Cramer in 1911, based on research by F. Hurter, V.C. Driffield and H. Luggin. By exposure the surface and the interior of a silver-bromide sphere will disintegrate by the expulsion of bromide. Whereas the bromide on the surface can permeate away, the bromide can not so easily permeate away from the interior. The overexposure generates now a bromide pressure that escapes from the internal sphere and permeates to the surface where it oxidizes the latent image situated there, constituting the regular latent image under normal exposures.
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The coastline of the island consists of a combination of long beaches, dunes, red sandstone cliffs, saltwater marshes and numerous bays and harbours. The beaches, dunes and sandstone cliffs consist of sedimentary rock and other material with a high iron concentration which oxidizes upon exposure to the air. The geological properties of white silica sand found at Basin Head are unique in the province; the sand grains cause a scrubbing noise as they rub against each other when walked on. Large dune fields on the north shore can be found on barrier islands at the entrances to various bays and harbours.
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The core aging requirement that defines a whiskey as straight is if the distillate has spent at least two years stored in charred new oak barrels, except corn whiskey which must use uncharred or used oak barrels. The spirit oxidizes during this aging period, and penetrates the wood, extracting many of the flavor compounds and caramelized wood sugars. A straight whiskey that has been aged less than four years is required to be labeled with an age statement describing the actual age of the product."Statements of Age", U.S. Alcohol and Tobacco Tax and Trade Bureau, April 2007, page 8-15.
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The instructions advise that the heater should rest against a "rock or something" Ration heaters generate heat in an electron-transfer process called an oxidation-reduction reaction. Water oxidizes magnesium metal, according to the following chemical reaction: : Mg + 2H2O -> Mg(OH)2 \+ H2 [+ heat (q)] This reaction is analogous to iron being rusted by oxygen, and proceeds at about the same slow rate, which is too slow to generate usable heat. To accelerate the reaction, metallic iron particles and table salt (NaCl) are mixed with the magnesium particles. Iron and magnesium metals, when suspended in an electrolyte, form a galvanic cell that can generate electricity.
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It is used in organic chemistry as a catalyst for the epoxidation of allylic alcohols by tert-butyl hydroperoxide (TBHP). The VO(acac)2–TBHP system exclusively epoxidizes geraniol at the allylic alcohol position, leaving the other alkene of geraniol untouched. By comparison, m-CPBA, another epoxidizing agent, reacts with both alkenes, creating the products in a two to one ratio favoring reaction at the alkene away from the hydroxyl group. TBHP oxidizes VO(acac)2 to a vanadium(V) species which coordinates the alcohol of the substrate and the hydroperoxide, directing the epoxidation to occur at the alkene close to this coordination site.
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Graphite plates and sheets, 10–15 cm high; mineral specimen from Kimmirut, Baffin Island The acoustic and thermal properties of graphite are highly anisotropic, since phonons propagate quickly along the tightly bound planes, but are slower to travel from one plane to another. Graphite's high thermal stability and electrical and thermal conductivity facilitate its widespread use as electrodes and refractories in high temperature material processing applications. However, in oxygen-containing atmospheres graphite readily oxidizes to form carbon dioxide at temperatures of 700 °C and above. Molar volume against pressure at room temperature Graphite is an electrical conductor, hence useful in such applications as arc lamp electrodes.
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Structure of Heme D. Cytochrome d is, as other proteins of its family, a membrane-bound hemeprotein, but unlike cytochromes a and b, cytochrome D has a heme D instead of a heme A or heme B group. Cytochrome d is part of the cytochrome bd terminal oxidase which catalyse the two electron oxidation of ubiquinol. This process is an oxidative phosphorylation that oxidizes the ubiquinol-8 to ubiquinone. The chemical reaction followed by this process is: :Ubiquinol-8 + O2 -> Ubiquinone-8 + H2OCytochrome d ubiquinol oxidase subunit 1 By a similar reaction, it also catalyses the reduction of oxygen to water, which involves 4 electrons.
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US: Springer. pp. 281–288. Silver carbonate on celite oxidizes alcohols through single electron oxidation by the silver cations Even weakly associating functionalities such as olefins can interfere with the association of the reactant alcohol with Fetizon's reagent The rate limiting step of this reaction is proposed to be the initial association of the alcohol to the silver ions. As a result, the presence of even weakly associating ligands to the silver can inhibit the reaction greatly. As a result, even slightly polar solvents of any variety, such as ethyl acetate or methyl ethyl ketone, are avoided when using this reagent as they competitively associate with the reagent.
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The inability of Fétizon's reagent to oxidize tertiary alcohols makes it extremely useful in the monooxidation of a [1,2] diol in which one of the alcohols is tertiary while avoiding cleavage of the carbon-carbon bond. Fetizon's reagent oxidizes secondary alcohols selectively in the presence of tertiary alcohols The mildness and structural sensitivity of the reagent also makes this reagent ideal for the monooxidation of a symmetric diol. Fetizon's reagent is capable of monooxidizing a symmetric diol Lactols are extremely sensitive to Fétizon's reagent, being oxidized very quickly to a lactone functionality. This allows for the selective oxidation of lactols in the presence of other alcohols.
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Sometimes a dehydrogenase catalyzed reaction will look like this: AH + B+ ↔ A+ \+ BH when a hydride is transferred. Alcohol dehydrogenase oxidizes ethanol, with the help of the electron carrier NAD+, yielding acetaldehydeA represents the substrate that will be oxidized, while B is the hydride acceptor. Note how when the hydride is transferred from A to B, the A has taken on a positive charge; this is because the enzyme has taken two electrons from the substrate in order to reduce the acceptor to BH. The result of a dehydrogenase catalyzed reaction is not always the acquisition of a positive charge. Sometimes the substrate loses a proton.
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BCDMH works in the following manner:South Australian Health Commission, "Standard for the Operation of Swimming Pools and Spa Pools in South Australia", Supplement C: Bromine Disinfection , page 8. Retrieved on 2009-05-12. The initial BCDMH reacts with water (R = Dimethylhydantoin): : BrClR + 2 H2O → HOBr + HOCl + RH2 Hypobromous acid partially dissociates in water: : HOBr → H+ \+ OBr− Hypobromous acid oxidizes the substrate, itself being reduced to bromide: : HOBr + Live pathogens → Br− \+ Dead pathogens The bromide ions are oxidized with the hypochlorous acid that was formed from the initial BCDMH: : Br− \+ HOCl → HOBr + Cl− This produces more hypobromous acid. However, the hypochlorous acid itself does act directly as a disinfectant in the process.
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When used for cutting, the plasma gas flow is increased so that the deeply penetrating plasma jet cuts through the material and molten material is removed as cutting dross. PAC differs from oxy-fuel cutting in that the plasma process operates by using the arc to melt the metal whereas in the oxy-fuel process, the oxygen oxidizes the metal and the heat from the exothermic reaction melts the metal. Unlike oxy-fuel cutting, the PAC process can be applied to cutting metals which form refractory oxides such as stainless steel, cast iron, aluminum and other non-ferrous alloys. Since PAC was introduced by Praxair Inc.
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Vat dyes are insoluble in water in their unreduced form, and the vat dye must be chemically reduced before they can be used to color fabric. This is accomplished by heating the dye in a strongly basic solution of sodium hydroxide (lye) or sodium carbonate (caustic potash) containing a reducing agent such as sodium hydrosulfite or thiourea dioxide. The fabric is immersed in the dye bath, and after removal the vat dye oxidizes to its insoluble form, binding with high wash-fastness to the fiber. However, vat dyes, and especially indigo, must be treated after dyeing by 'soaping' to prevent the dye from rubbing (crocking) off.
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Bioaccumulation (a buildup of a certain substance in the adipose tissue) and biomagnification (the process in which the concentration of the substance grows higher as you rise through the food chain) are growing issues in the mesopelagic zone. Mercury in fish, which can be traced back to a combination of anthropological factors (such as coal mining) in addition to natural factors. Mercury is a particularly important bioaccumulation contaminant because its concentration in the mesopelagic zone is increasing faster than in surface waters. Inorganic mercury occurs in anthropogenic atmospheric emissions in its gaseous elemental form, which then oxidizes and can be deposited in the ocean.
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One major problem with older breath analyzers is non-specificity: the machines identify not only the ethyl alcohol (or ethanol) found in alcoholic beverages but also other substances similar in molecular structure or reactivity. The oldest breath analyzer models pass breath through a solution of potassium dichromate, which oxidizes ethanol into acetic acid, changing color in the process. A monochromatic light beam is passed through this sample, and a detector records the change in intensity and, hence, the change in color, which is used to calculate the percent alcohol in the breath. However, since potassium dichromate is a strong oxidizer, numerous alcohol groups can be oxidized by it, producing false positives.
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The biosynthesis of ribostamycin begins with the sugar, D-glucose, which is phosphorylated at the 6 position to form glucose-6-phosphate. The enzyme rbmA contains a genetic sequence that corresponds to NAD+ binding and catalyzes the formation of 2-deoxy-scyllo- inosose. The enzyme rmbB then catalyzes the transamination of 2-deoxy-scyllo- inosose to 2-deoxy-scyllo-inosamine with L-glutamine and pyridoxal phosphate (PLP). Enzyme rbmC oxidizes the ring to 2-deoxy-3-amino-scyllo-inosose, which is then transaminated by enzyme rmbB to DOS. DOS is then glycosylated by the glycosyltransferase rmbD with uridine diphosphate N-acetylglucosamine (UDP- Glc-NAc) to form 2’-N-acetylparomamine.
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Proposed structure of Manganese Center The oxygen-evolving complex is the site of water oxidation. It is a metallo-oxo cluster comprising four manganese ions (in oxidation states ranging from +2 to +4) and one divalent calcium ion. When it oxidizes water, producing oxygen gas and protons, it sequentially delivers the four electrons from water to a tyrosine (D1-Y161) sidechain and then to P680 itself. The first structural model of the oxygen-evolving complex was solved using X-ray crystallography from frozen protein crystals with a resolution of 3.8Å in 2001. Over the next years the resolution of the model was gradually increased to 2.9Å.
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Iron alloys are most broadly divided by their carbon content: cast iron has 2–4% carbon impurities; wrought iron oxidizes away most of its carbon, to less than 0.1%. The much more valuable steel has a delicately intermediate carbon fraction, and its material properties range according to the carbon percentage: high carbon steel is stronger but more brittle than low carbon steel. Crucible steel sequesters the raw input materials from the heat source, allowing precise control of carburization (raising) or oxidation (lowering carbon content). Fluxes, such as limestone, could be added to the crucible to remove or promote sulfur, silicon, and other impurities, further altering its material qualities.
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With the production of the melanin, the skin color darkens. The tanning process can be triggered by natural sunlight or by artificial UV radiation, which can be delivered in frequencies of UVA, UVB, or a combination of both. The intensity is commonly measured by the UV Index. Cross-sectional view showing skin tone becoming darker due to the production of more melanin to overcome DNA damage caused by UV radiation There are two different mechanisms involved in production of a tan by UV exposure: Firstly, UVA radiation creates oxidative stress, which in turn oxidizes existing melanin and leads to rapid darkening of the melanin.
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Inositol oxygenase, also commonly referred to as myo-inositol oxygenase (MIOX), is a non-heme di-iron enzyme that oxidizes myo-inositol to glucuronic acid. The enzyme employs a unique four-electron transfer at its Fe(II)/Fe(III) coordination sites and the reaction proceeds through the direct binding of myo-inositol followed by attack of the iron center by diatomic oxygen. This enzyme is part of the only known pathway for the catabolism of inositol in humans and is expressed primarily in the kidneys. Recent medical research regarding MIOX has focused on understanding its role in metabolic and kidney diseases such as diabetes, obesity and acute kidney injury.
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Inside St. Stephen's The organ The present church, in the style of Dalmatian Baroque, is a large three- nave basilica with a square apse, built of stone from the nearby island of Korčula which oxidizes over time and takes on a red-brown colour. It is the work of local craftsmen. The main portal in the centre of the west-facing façade, and probably the entire façade, is the work of Ivan Pomenić from Korčula who also worked on the Cathedral of St. Stephen in Hvar. The two side aisles are the work of Mark Foretić from Korčula and of the master of the Skarpa-family of Stari Grad.
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Once in the environment, neptunium generally oxidizes fairly quickly, usually to the +4 or +5 state. Regardless of its oxidation state, the element exhibits a much greater mobility than the other actinides, largely due to its ability to readily form aqueous solutions with various other elements. In one study comparing the diffusion rates of neptunium(V), plutonium(IV), and americium(III) in sandstone and limestone, neptunium penetrated more than ten times as well as the other elements. Np(V) will also react efficiently in pH levels greater than 5.5 if there are no carbonates present and in these conditions it has also been observed to readily bond with quartz.
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Due to the oxidative properties of oxygen, most nitrogenases are irreversibly inhibited by dioxygen, which degradatively oxidizes the Fe-S cofactors. This requires mechanisms for nitrogen fixers to protect nitrogenase from oxygen in vivo. Despite this problem, many use oxygen as a terminal electron acceptor for respiration. Although the ability of some nitrogen fixers such as Azotobacteraceae to employ an oxygen-labile nitrogenase under aerobic conditions has been attributed to a high metabolic rate, allowing oxygen reduction at the cell membrane, the effectiveness of such a mechanism has been questioned at oxygen concentrations above 70 μM (ambient concentration is 230 μM O2), as well as during additional nutrient limitations.
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In enzymology, an L-2-hydroxyglutarate dehydrogenase () is an enzyme that catalyzes the chemical reaction :(S)-2-hydroxyglutarate + acceptor \rightleftharpoons 2-oxoglutarate + reduced acceptor Thus, the two substrates of this enzyme are (S)-2-hydroxyglutarate and acceptor, whereas its two products are 2-oxoglutarate and reduced acceptor. Enzymes which preferentially catalyze the conversion of the (R) stereoisomer of 2-oxoglutarate also exist in both mammals and plants and are named D-2-hydroxyglutarate dehydrogenase. L-2-hydroxyglutarate is produced by promiscuous action of malate dehydrogenase on 2-oxoglutarate; L-2-hydroxyglutarate dehydrogenase is an example of a metabolite repair enzyme that oxidizes L-2-hydroxyglutarate back to 2-oxoglutarate.
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The newly formed tricoordinated phosphite triester linkage is not natural and is of limited stability under the conditions of oligonucleotide synthesis. The treatment of the support-bound material with iodine and water in the presence of a weak base (pyridine, lutidine, or collidine) oxidizes the phosphite triester into a tetracoordinated phosphate triester, a protected precursor of the naturally occurring phosphate diester internucleosidic linkage. Oxidation may be carried out under anhydrous conditions using tert-Butyl hydroperoxide or, more efficiently, (1S)-(+)-(10-camphorsulfonyl)-oxaziridine (CSO). The step of oxidation may be substituted with a sulfurization step to obtain oligonucleotide phosphorothioates (see Oligonucleotide phosphorothioates and their synthesis below).
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The binding of calcium ions in this way very often triggers the function or binding of Gla-protein enzymes, such as the so-called vitamin K–dependent clotting factors discussed below. Within the cell, vitamin K undergoes electron reduction to a reduced form called vitamin K hydroquinone, catalyzed by the enzyme vitamin K epoxide reductase (VKOR). Another enzyme then oxidizes vitamin K hydroquinone to allow carboxylation of Glu to Gla; this enzyme is called gamma-glutamyl carboxylase or the vitamin K–dependent carboxylase. The carboxylation reaction only proceeds if the carboxylase enzyme is able to oxidize vitamin K hydroquinone to vitamin K epoxide at the same time.
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Other studies report that plants uptake large quantities of heavy metals and toxic pollutants that are retained by produce, which is then consumed by humans. A PhD thesis studying the addition of sludge to neutralize soil acidity concluded that the practice was not recommended if large amounts are used because the sludge produces acids when it oxidizes. Studies have indicated that pharmaceuticals and personal care products, which often adsorb to sludge during wastewater treatment, can persist in agricultural soils following biosolid application. Some of these chemicals, including potential endocrine disruptor Triclosan, can also travel through the soil column and leach into agricultural tile drainage at detectable levels.
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A specialized use of manganese dioxide is as oxidant in organic synthesis.. The effectiveness of the reagent depends on the method of preparation, a problem that is typical for other heterogeneous reagents where surface area, among other variables, is a significant factor.. The mineral pyrolusite makes a poor reagent. Usually, however, the reagent is generated in situ by treatment of an aqueous solution with a Mn(II) salt, typically the sulfate. oxidizes allylic alcohols to the corresponding aldehydes or ketones: (this procedure illustrates the use of MnO2 for the oxidation of an allylic alcohol. ::cis-RCH= + → cis-RCH=CHCHO + MnO + The configuration of the double bond is conserved in the reaction.
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This was the first time the versatile action of a single P450 enzyme was reported. The authors also evaluated the in vitro action of the flavin-dependent oxidoreductase, formerly characterized by Mo et al., against intermediates alone and with the presence of the TamI P450, and were able to show that these enzymes work together: TamI first hydroxylates the C10 of tirandamycin C to form tirandamycin E, then the flavin-dependent enzyme converts further oxidizes C10 into a carbonyl to form tirandamycin D, which then becomes a substrate for the TamI P450 that inserts an epoxide in the C11/C12 olefin (see Figure 4).
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AMD is formed by weathering that oxidizes sulfur minerals to sulfate and acid, and this process is exacerbated by microbes that oxidize reduced minerals. The production of acid, including sulfuric acid, causes metals to leach from waste rock into water and has contaminated nearby Joe Creek with cadmium, copper, lead, arsenic and zinc at levels that are toxic to aquatic life. Joe Creek is unable to contain any self-sustaining populations of fish due to the mining waste. The waste at Blue Ledge is particularly hazardous because it is mainly composed of small particles, which have greatly increased surface area when compared to large rocks, and therefore a high rate of metal leaching.
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When aluminum makes contact with water, hydrogen gas is produced as a result of hydrolysis. However, at the same time, water oxidizes the aluminum and causes a thin protective layer of aluminum oxide to rapidly form on the surface of the metal, preventing further hydrolysis. In order for the aluminum to continuously produce hydrogen gas, scientists had to forcefully remove or at least fracture the aluminum oxide layer, typically dissolving it in water with the help of hazardous compounds such as hydrochloric acid, sodium hydroxide, or expensive elements such as gallium/indium. Other methods apply external energy in the form of an electric current or superheated steam to slowly force the reaction at elevated temperatures.
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The Tsuji-Wacker Oxidation oxidizes terminal olefin to the corresponding methyl ketone under the Wacker process condition. Almost identical to that of Wacker Process, the proposed catalytic cycle(Figure 1) begins with complexation of PdCl2 and two chloride anions to PdCl4, which then undergoes subsequent ligand exchange of two chloride ligand for water and alkene to form Pd(Cl2)(H2O)(alkene) complex. A water molecule then attacks the olefin regioselectively through an outer sphere mechanism in a Markovnikov fashion, to form the more thermodynamically stable Pd(Cl2)(OH)(-CH2-CHOH-R) complex. Dissociation of a chloride ligand to the three coordinate palladium complex promotes β-hydride elimination, then subsequent 1,2-hydride insertion generates Pd(Cl2)(OH)(-CHOHR-CH3) complex.
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Corticosteroid 11-β-dehydrogenase isozyme 2 is an NAD+-dependent enzyme expressed in aldosterone-selective epithelial tissues such as the kidney, colon, salivary and sweat glands. HSD211B2 expression is also found in the brainstem in a small, aldosterone-sensitive subset of neurons located in the nucleus of the solitary tract referred to as HSD2 neurons. In these tissues, HSD11B2 oxidizes the glucocorticoid cortisol to the inactive metabolite cortisone, thus preventing illicit activation of the mineralocorticoid receptor. This protective mechanism is necessary because cortisol circulates at 100- to 1000-fold higher concentrations than aldosterone, and binds with equal affinity to the mineralocorticoid receptor, thereby out-competing aldosterone in cells that do not produce HSD11B2.
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A video describing the process of electrolytic reduction as used on Captain Kidd's Cannon at The Children's Museum of Indianapolis As already noted, water, particularly when ions are added (salt water or acidic water), can be electrolyzed (subject to electrolysis). When driven by an external source of voltage, H ions flow to the cathode to combine with electrons to produce hydrogen gas in a reduction reaction. Likewise, OH ions flow to the anode to release electrons and an H ion to produce oxygen gas in an oxidation reaction. In molten sodium chloride, when a current is passed through the salt the anode oxidizes chloride ions (Cl) to chlorine gas, releasing electrons to the anode.
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After drawing or spinning, the polymer filament yarns are then heated to drive off non-carbon atoms (carbonization), producing the final carbon fiber. The carbon fibers filament yarns may be further treated to improve handling qualities, then wound on to bobbins. Carbon fiber preparation Flexibility of Carbon rayon based fabric A common method of manufacture involves heating the spun PAN filaments to approximately 300 °C in air, which breaks many of the hydrogen bonds and oxidizes the material. The oxidized PAN is then placed into a furnace having an inert atmosphere of a gas such as argon, and heated to approximately 2000 °C, which induces graphitization of the material, changing the molecular bond structure.
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There the oxygen in H2O2 binds to an Fe(III) ion in the heme cofactor to form an iron peroxide complex. Two electrons are transferred from Fe3+ to peroxide, breaking the oxygen-peroxide bond to form H2O and a Fe(IV) oxo- porphyrin radical complex. This oxidized intermediate is known as MnP Compound I. MnP Compound I then binds to a monochelated Mn(II) ion, which donates an electron to quench the radical and form Mn(III) and MnP Compound II, a Fe(IV) oxo-porphyrin complex. MnP Compound II oxidizes another Mn(II) ion to Mn(III) and is reduced by the reaction of two H+ ions and the iron bound oxygen.
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During normal plant operations and in normal operating temperatures, the hydrogen generation is not significant. When the nuclear fuel overheats, zirconium in Zircaloy cladding used in fuel rods oxidizes in reaction with steam: :Zr + 2H2O → ZrO2 \+ 2H2 When mixed with air, hydrogen is flammable, and hydrogen detonation or deflagration may damage the reactor containment. In reactor designs with small containment volumes, such as in Mark I or II containments, the preferred method for managing hydrogen is pre-inerting with inert gas—generally nitrogen—to reduce the oxygen concentration in air below that needed for hydrogen combustion, and the use of thermal recombiners. Pre-inerting is considered impractical with larger containment volumes where thermal recombiners and deliberate ignition are used.
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As the primary regulators of a crucial step in the central metabolic pathway, the pyruvate dehydrogenase family is tightly regulated itself by a myriad of factors. PDK2 activity is modulated by low levels of hydrogen peroxide; this happens because the compound temporarily oxidizes the cysteine residues 45 and 392 on the enzyme, resulting in an inactive PDK2 and greater PDH activity. These conditions also inactivate the TCA cycle, the next step in aerobic respiration. This alludes to the fact that when there is a high level of O2 production in the mitochondria, which may occur because of nutrient excess, the increase in the products serve as a negative feedback that control mitochondria metabolism.
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Periodic acid Periodic acid–Schiff (PAS) is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids and mucins in tissues. The reaction of periodic acid oxidizes the vicinal diols in these sugars, usually breaking up the bond between two adjacent carbons not involved in the glycosidic linkage or ring closure in the ring of the monosaccharide units that are parts of the long polysaccharides, and creating a pair of aldehydes at the two free tips of each broken monosaccharide ring. The oxidation condition has to be sufficiently regulated so as to not oxidize the aldehydes further. These aldehydes then react with the Schiff reagent to give a purple-magenta color.
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Nickel(II) hydroxide is frequently used in electrical car batteries. Specifically, Ni(OH)2 readily oxidizes to nickel oxyhydroxide, NiOOH, in combination with a reduction reaction, often of a metal hydride (reaction 1 and 2). Reaction 1 Ni(OH)2 \+ OH− → NiO(OH) + H2O + e− Reaction 2 M + H2O + e− → MH + OH− Net Reaction (in H2O) Ni(OH)2 \+ M → NiOOH + MH Of the two polymorphs, α-Ni(OH)2 has a higher theoretical capacity and thus is generally considered to be preferable in electrochemical applications. However, it transforms to β-Ni(OH)2 in alkaline solutions, leading to many investigations into the possibility of stabilized α-Ni(OH)2 electrodes for industrial applications.
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Bacterial alteration of anhydrite or gypsum, in the presence of hydrocarbons, produces limestone and hydrogen sulfide in the sulfur cycle. The hydrogen sulfide then oxidizes into sulfur, from percolating water, or through the action of anaerobic, sulfur-reducing bacteria In 1867, miners discovered sulfur in the caprock of a salt dome in Calcasieu Parish, Louisiana, but it was beneath quicksand, which prevented mining. In 1894 the German-born American chemist, Herman Frasch (1852–1914), devised his Frasch method of sulfur removal using pipes to bypass the quicksand.. This replaced the inefficient and polluting Sicilian method. The process proved successful, on December 24, 1894, when the first molten sulfur was brought to the surface.
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Cytochrome b559 is an important component of Photosystem II. PSII is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. Within the core of the complex, the chlorophyll and beta-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to chlorophylls in the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process. The PSII oxygen-evolving complex (OEC) provides electrons to re- reduce the PSII reaction center, and oxidizes 2 water molecules to recover its reduced initial state. It consists of OEE1 (PsbO), OEE2 (PsbP) and OEE3 (PsbQ).
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In the liquid exfoliation method first reported by Brent et al. in 2014 and modified by others, bulk black phosphorus is first ground in a mortar and pestle and then sonicated in deoxygenated, anhydrous organic liquids such as NMP under an inert atmosphere using low-power bath sonication. Suspensions are then centrifuged for 30 minutes to filter out the unexfoliated black phosphorus. Resulting 2D monolayer and few-layer phosphorene unoxidized and crystalline structure, while exposure to air oxidizes the phosphorene and produces acid. Another variation of liquid exfoliation is “basic N-methyl-2-pyrrolidone (NMP) liquid exfoliation”. Bulk black phosphorene is added to a saturated NaOH/NMP solution, which is further sonicated for 4 hours to conduct liquid exfoliation.
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Flame ionization detectors cannot detect inorganic substances and some highly oxygenated or functionalized species like infrared and laser technology can. In some systems, CO and CO2 can be detected in the FID using a methanizer, which is a bed of Ni catalyst that reduces CO and CO2 to methane, which can be in turn detected by the FID. The methanizer is limited by its inability to reduce compounds other than CO and CO2 and its tendency to be poisoned by a number of chemicals commonly found in gas chromatography effluents. Another important disadvantage is that the FID flame oxidizes all oxidizable compounds that pass through it; all hydrocarbons and oxygenates are oxidized to carbon dioxide and water and other heteroatoms are oxidized according to thermodynamics.
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Thyroid hormone synthesis, with thyroid peroxidase performing the oxidation step seen at center-left in the image. Inorganic iodine enters the body primarily as iodide, I−. After entering the thyroid follicle (or thyroid follicular cell) via a Na+/I− symporter (NIS) on the basolateral side, iodide is shuttled across the apical membrane into the colloid via pendrin, after which thyroid peroxidase oxidizes iodide to atomic iodine (I) or iodinium (I+). The "organification of iodine," the incorporation of iodine into thyroglobulin for the production of thyroid hormone, is nonspecific; that is, there is no TPO- bound intermediate, but iodination occurs via reactive iodine species released from TPO. The chemical reactions catalyzed by thyroid peroxidase occur on the outer apical membrane surface and are mediated by hydrogen peroxide.
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Some cities ban, or used to ban, wood fires; when residents only use charcoal (and similarly-treated rock coal, called coke) air pollution is significantly reduced. In cities where people do not generally cook or heat with fires, this is not needed. In the mid-20th century, "smokeless" legislation in Europe required cleaner-burning techniques, such as coke fuel and smoke-burning incineratorsSmokeless incinerator patent as an effective measure to reduce air pollution A blacksmith's forge, with a blower forcing air through a bed of fuel to raise the temperature of the fire. On the periphery, coal is pyrolyzed, absorbing heat; the coke at the center is almost pure carbon, and releases a lot of heat when the carbon oxidizes.
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Benzylic and allylic alcohols react faster than saturated alcohols, while DMP oxidizes aldoximes and ketoximes to their respective aldehydes and ketones, faster than a primary, secondary or benzylic alcohol to its respective carbonyl. In one example of the Dess–Martin oxidation, involves transforming a sensitive α-β-unsaturated alcohol to its corresponding aldehyde. This moiety has been found in several natural products and due to its high functionality, it could be a valuable synthetic building block in organic synthesis. Thongsornkleeb and Danheiser oxidized this sensitive alcohol by employing the Dess Martin Oxidation and altering the work up procedure (diluting with pentanes, washing with poly(4-vinylpyridine) to remove the acetic acid generated during the reaction, filtering and concentrating via distillation.
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An experimental iodine clock sequence has also been established for a system consisting of iodine potassium-iodide, sodium chlorate and perchloric acid that takes place through the following reactions. Triiodide is present in equilibrium with iodide anion and molecular iodine: : Chlorate ion oxidizes iodide ion to hypoiodous acid and chlorous acid in the slow and rate-determining step: : Chlorate consumption is accelerated by reaction of hypoiodous acid to iodous acid and more chlorous acid: : More autocatalysis when newly generated iodous acid also converts chlorate in the fastest reaction step: : In this clock the induction period is the time it takes for autocatalytic process to start after which the concentration of free iodine falls rapidly as observed by UV/VIS spectroscopy.
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1583 The yields are much higher for reactor irradiation, but there, the product is a mixture of various actinide isotopes, as well as lanthanides produced in the nuclear fission decays. In this case, isolation of einsteinium is a tedious procedure which involves several repeating steps of cation exchange, at elevated temperature and pressure, and chromatography. Separation from berkelium is important, because the most common einsteinium isotope produced in nuclear reactors, 253Es, decays with a half-life of only 20 days to 249Bk, which is fast on the timescale of most experiments. Such separation relies on the fact that berkelium easily oxidizes to the solid +4 state and precipitates, whereas other actinides, including einsteinium, remain in their +3 state in solutions.
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Renalase has been claimed to degrade catecholamines like adrenaline (epinephrine) and noradrenaline (norepinephrine) in the blood circulation. Dr. Gary Desir's laboratory at Yale School of Medicine discovered and named renalase in 2005 suggest that the human kidney releases this protein into the bloodstream to regulate blood pressure (in addition to other possible, as yet undiscovered, functions). Whether renalase actually oxidizes catecholamine substrates has been widely disputed. The primary evidence for catecholamine oxidation is the detection of H2O2, however catecholamines emanate H2O2 in the presence of O2 in a natural decomposition reaction. In 2013, renalase was claimed to oxidize α-NADH (the normal form of NADH is the β anomer) to β-NAD, with concomitant reduction of O2 (dioxygen) to H2O2 (hydrogen peroxide).
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Sulfide inclusion as manganese sulfide (MnS) can also be the cause of severe pitting corrosion problems in low-grade stainless steel such as AISI 304 steel. Under oxidizing conditions and in the presence of moisture, when sulfide oxidizes it produces thiosulfate anions as intermediate species and because thiosulfate anion has a higher equivalent electromobility than chloride anion due to its double negative electrical charge, it promotes the pit growth. Indeed, the positive electrical charges born by Fe2+ cations released in solution by Fe oxidation on the anodic zone inside the pit must be quickly compensated / neutralised by negative charges brought by the electrokinetic migration of anions in the capillary pit. Some of the electrochemical processes occurring in a capillary pit are the same than these encountered in capillary electrophoresis.
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A. thiooxidans uses elemental sulfur as its primary energy source and oxidizes it by the sulfide-quinone reductase and sox pathways. Sulfur is oxidized to sulfuric acid by A. thiooxidans and the energy liberated is used for growth and maintenance. In addition to sulfur, A. thiooxidans can use thiosulfate or tetrathionate as sources of energy, but growth in a liquid medium on thiosulfate is slow, generally taking about 10 to 12 days under favorable conditions as opposed to only 4 to 5 days for growth on elemental sulfur, as demonstrated by the change in pH and turbidity. A. thiooxidans is incapable of oxidizing iron or pyrite, but it has been shown to grow on sulfur from pyrite when cocultured with the bacterium Leptospirillum ferrooxidans, a species that can oxidize iron but not sulfur.
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First, the sulfide concentrate is roasted in air to oxidize the lead sulfide: : 2 PbS(s) + 3 O2(g) → 2 PbO(s) + 2 SO2(g)↑ As the original concentrate was not pure lead sulfide, roasting yields not only the desired lead(II) oxide, but a mixture of oxides, sulfates, and silicates of lead and of the other metals contained in the ore. This impure lead oxide is reduced in a coke-fired blast furnace to the (again, impure) metal: : 2 PbO(s) + C(s) → 2 Pb(s) + CO2(g)↑ Impurities are mostly arsenic, antimony, bismuth, zinc, copper, silver, and gold. Typically they are removed in a series of pyrometallurgical processes. The melt is treated in a reverberatory furnace with air, steam, and sulfur, which oxidizes the impurities except for silver, gold, and bismuth.
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The severe limitations on the arene component scope in this reaction is due primarily to the need for an arene radical anion that is stable enough not to react directly with enamine or enamine radical cation. In the proposed mechanism, the activated photoredox catalyst is quenched oxidatively by an electron-deficient arene, such as 1,4-dicyanobenzene. The photocatalyst then oxidizes an enamine species, transiently generated by the condensation of an aldehyde with a secondary amine cocatalyst, such as the optimal isopropyl benzylamine. The resulting enamine radical cation usually reacts as a 3 π-electron system, but due to the stability of the radical coupling partners, deprotonation of the β-methylene position gives rise to a 5 π-electron system with strong radical character at the newly accessed β-carbon.
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Methylated cytosine can also be demethylated, an epigenetic alteration that can increase the expression of a gene. A major enzyme involved in demethylating 5mCpG is TET1. However, TET1 is only able to act on 5mCpG if an ROS has first acted on the guanine to form 8-hydroxy-2'-deoxyguanosine (8-OHdG), resulting in a 5mCp-8-OHdG dinucleotide (see first figure). However, TET1 is only able to act on the 5mC part of the dinucleotide when the base excision repair enzyme OGG1 binds to the 8-OHdG lesion without immediate excision. Adherence of OGG1 to the 5mCp-8-OHdG site recruits TET1 and TET1 then oxidizes the 5mC adjacent to 8-OHdG, as shown in the first figure, initiating a demethylation pathway shown in the second figure.
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Developed as a joint project between the US Navy and the DuPont Chemical company, the EX 1 and EX 2 were part of the Target Illumination and Recovery Aid (TIARA) program. DuPont created a number of essentially glow-in-the-dark fillers, finally settling on the non-toxic PB-155 compound. PB-155 (also known as TIARA 5) glows when it oxidizes and therefore could be used to mark things at night with minimal fuss. Developed specifically for the US Navy SEALs, the first production models were created in 1963. The EX 1 Mod 0 was a hand grenade, based on the M25A2 chemical grenade described in the following section. Testing in 1963 showed that the TIARA 5 mixture had averse effects on the functioning of the C12 fuze integral to the M25A2 design.
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Hoffman informs them that there are two lethal bioweapons in the laboratory, a strain of botulinus that oxidizes eight hours after its release, and a recently developed virus that he calls the "Satan Bug", which could kill all life on Earth in a matter of months. Determined to discover what happened in the room and taking extreme precautions, Barrett enters to find Dr. Baxter dead, with the vials containing the "Satan Bug" and 1200 grams of botulinus missing. A mysterious telegram leads Barrett to a nearby hotel where he has a surprise reunion with his old flame, Ann, the daughter of his superior, General Williams, who has flown in from Washington to supervise the investigation. Ann reveals that she sent the telegram, and that she has been assigned to Barrett as his partner, an arrangement neither minds.
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In particular, heterozygous OGG1+/- mice, with about half the protein level of OGG1, exhibit poorer learning performance in the Barnes maze compared to wild-type animals. In adult somatic cells, such as neurons, DNA methylation typically occurs in the context of CpG dinucleotides (CpG sites), forming 5-methylcytosine (5mC). Thus, a CpG site may be methylated to form 5mCpG. The presence of 5mC at CpG sites in gene promoters is widely considered to be an epigenetic mark that acts to suppress transcription. If the guanine at the 5mCpG site is attacked by ROS, leading to 8-OHdG formation, OGG1 binds to the 8-OHdG lesion without immediate excision of the 8-OHdG. When OGG1 is present at a 5mCp-8-OHdG site, it recruits TET1 to the 8-OHdG lesion and TET1 oxidizes the 5mC adjacent to 8-OHdG.
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This reversible bonding with oxygen is why hemoglobin is so useful for transporting oxygen around the body. Oxygen binds in an "end-on bent" geometry where one oxygen atom binds to Fe and the other protrudes at an angle. When oxygen is not bound, a very weakly bonded water molecule fills the site, forming a distorted octahedron. Even though carbon dioxide is carried by hemoglobin, it does not compete with oxygen for the iron-binding positions but is bound to the amine groups of the protein chains attached to the heme groups. The iron ion may be either in the ferrous Fe2+ or in the ferric Fe3+ state, but ferrihemoglobin (methemoglobin) (Fe3+) cannot bind oxygen. In binding, oxygen temporarily and reversibly oxidizes (Fe2+) to (Fe3+) while oxygen temporarily turns into the superoxide ion, thus iron must exist in the +2 oxidation state to bind oxygen.
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Fig 3. CLR using a circulating fluidized bed configuration Fig 4. CLR system with a moving bed reducer Chemical looping systems can directly be engaged as an effective means for syngas production. Compared to the conventional partial oxidation (POX) or autothermal reforming (ATR) processes, the key advantage of the chemical looping reforming (CLR) process is the elimination of the air separation unit (ASU) for oxygen production. The gaseous fuel, typically natural gas, is fed to the fuel reactor, in which a solid metal oxide oxygen carrier partially oxidizes the fuel to generate syngas: :CH4 \+ MeOx → CO + 2H2 \+ MeOx-δ Steam can be added to the reaction in order to increase the generation of H2, via the water-gas shift reaction (WGS) and/or steam methane reforming. The CLR process can produce a syngas with a H2:CO molar ratio of 2:1 or higher, which is suitable for Fischer-Tropsch synthesis, methanol synthesis, or hydrogen production.
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Dilute solutions of KMnO4 convert alkenes into diols (glycols). This behaviour is also used as a qualitative test for the presence of double or triple bonds in a molecule, since the reaction decolorizes the initially purple permanganate solution and generates a brown precipitate (MnO2). In this context, it is sometimes called Baeyer's reagent. However, bromine serves better in measuring unsaturation (double or triple bonds) quantitatively, since KMnO4, being a very strong oxidizing agent, can react with a variety of groups. Under acidic conditions, the alkene double bond is cleaved to give the appropriate carboxylic acid: : CH3(CH2)17CH=CH2 \+ 2 KMnO4 \+ 3 H2SO4 → CH3(CH2)17COOH + CO2 \+ 4 H2O + K2SO4 \+ 2 MnSO4 Potassium permanganate oxidizes aldehydes to carboxylic acids, such as the conversion of n-heptanal to heptanoic acid: :5 C6H13CHO + 2 KMnO4 \+ 3 H2SO4 → 5 C6H13COOH + 3 H2O + K2SO4 \+ 2 MnSO4 Even an alkyl group (with a benzylic hydrogen) on an aromatic ring is oxidized, e.g.
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Formation of zirconium hydrides is an important factor in the operation of several types of nuclear reactors, such as boiling water reactors Fukushima I and II, which suffered from a series of explosions caused by the 2011 Tōhoku earthquake and tsunami. Their uranium fuel pellets are enclosed in metal rods made from Zircaloy – an alloy of typically about 98.25% zirconium with 1.5% tin and minor amounts of other metals. Zircaloy is used because of its small absorption cross-section for thermal neutrons and superior mechanical and corrosion properties to those of most metals, including zirconium.DOE-HDBK-1017/2-93 JANUARY 1993, DOE FUNDAMENTALS HANDBOOK, MATERIAL SCIENCE, Volume 2 of 2, U.S. Department of Energy january 2003, pp. 12, 24Nuclear Fuel Fabrication , Fuel Fabrication World Nuclear Association, March 2010Delayed hydride cracking in zirconium alloys in pressure tube nuclear reactors, Final report of a coordinated research project 1998–2002, IAEA, October 2004 The rods are cooled by streaming water which gradually oxidizes zirconium, liberating hydrogen.
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Sulfur dioxide is generated by burning elemental sulfur or by roasting pyritic ore in a current of air: :S8 \+ 8 O2 → 8 SO2 :4 FeS2 \+ 11 O2 → 2 Fe2O3 \+ 8 SO2 Nitrogen oxides are produced by decomposition of niter in the presence of sulfuric acid, or by hydrolysis of nitrosylsulfuric acid: :2 NaNO3 \+ H2SO4 → Na2SO4 \+ H2O + NO + NO2 \+ O2 :2 NOHSO4 \+ H2O → 2 H2SO4 \+ NO + NO2 In the reaction chambers, sulfur dioxide and nitrogen dioxide dissolve in the reaction liquor. Nitrogen dioxide is hydrated to produce nitrous acid, which then oxidizes the sulfur dioxide to sulfuric acid and nitric oxide. The reactions are not well characterized, but it is known that nitrosylsulfuric acid is an intermediate in at least one pathway. The major overall reactions are: :2 NO2 \+ H2O → HNO2 \+ HNO3 :SO2 (aq) + HNO3 → NOHSO4 :NOHSO4 \+ HNO2 → H2SO4 \+ NO2 \+ NO :SO2 (aq) + 2 HNO2 → H2SO4 \+ 2 NO Nitric oxide escapes from the reaction liquor and is subsequently reoxidized by molecular oxygen to nitrogen dioxide.
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In the liver, the carboxylation of cytosolic pyruvate into intra- mitochondrial oxaloacetate is an early step in the gluconeogenic pathway, which converts lactate and de-aminated alanine into glucose, under the influence of high levels of glucagon and/or epinephrine in the blood. Here, the addition of oxaloacetate to the mitochondrion does not have a net anaplerotic effect, as another citric acid cycle intermediate (malate) is immediately removed from the mitochondrion to be converted into cytosolic oxaloacetate, which is ultimately converted into glucose, in a process that is almost the reverse of glycolysis. The enzymes of the citric acid cycle are located in the mitochondrial matrix, with the exception of succinate dehydrogenase, which is bound to the inner mitochondrial membrane as part of Complex II. The citric acid cycle oxidizes the acetyl-CoA to carbon dioxide, and, in the process, produces reduced cofactors (three molecules of NADH and one molecule of FADH2) that are a source of electrons for the electron transport chain, and a molecule of GTP (that is readily converted to an ATP).
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In water, chloramine is pH-neutral. It is an oxidizing agent (acidic solution: , in basic solution ): : NH2Cl + 2 H+ \+ 2 e− → + Cl− Reactions of chloramine include radical, nucleophilic, and electrophilic substitution of chlorine, electrophilic substitution of hydrogen, and oxidative additions. Chloramine can, like hypochlorous acid, donate positively charged chlorine in reactions with nucleophiles (Nu−): : Nu− \+ NH3Cl+ → NuCl + NH3 Examples of chlorination reactions include transformations to dichloramine and nitrogen trichloride in acidic medium, as described in the decomposition section. Chloramine may also aminate nucleophiles (electrophilic amination): : Nu− \+ NH2Cl → NuNH2 \+ Cl− The amination of ammonia with chloramine to form hydrazine is an example of this mechanism seen in the Olin Raschig process: : NH2Cl + NH3 \+ NaOH → N2H4 \+ NaCl + H2O Chloramine electrophilically aminates itself in neutral and alkaline media to start its decomposition: : 2 NH2Cl → N2H3Cl + HCl The chlorohydrazine (N2H3Cl) formed during self-decomposition is unstable and decomposes itself, which leads to the net decomposition reaction: : 3 NH2Cl → N2 \+ NH4Cl + 2 HCl Monochloramine oxidizes sulfhydryls and disulfides in the same manner as hypochlorous acid, but only possesses 0.4% of the biocidal effect of HClO.
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Storage conditions with moisture and high temperatures are detrimental to sodium bismuthate, as it oxidizes water, decomposing into sodium hydroxide and bismuth(III) oxide: :2 NaBiO3 \+ H2O → 2 NaOH + Bi2O3 \+ O2 It is decomposed faster by acids. In HCl, NaBiO3 also reacts to form chlorine gas. NaBiO3 may be used to detect manganese qualitatively and quantitatively. As a strong oxidizer, it converts almost any manganese compound to permanganate, which is easily assayed spectrophotometrically. To do this, some NaBiO3 and the sample are reacted in a hot solution of sulfuric acid or nitric acid. Permanganate has a violet color and maximum absorbance at 510 nm. The reaction is: :2 Mn2+ \+ 5 NaBiO3 \+ 14 H+ → 2 MnO4− \+ 5 Bi3+ \+ 5 Na+ \+ 7 H2O Sodium bismuthate can perform oxidative 1,2-cleavage on glycols, ketols and alpha hydroxy acids with no further oxidation of the (possible) aldehyde products:Suzuki, p. 373 :R2C(OH)–C(OH)–R2 → R2C=O + O=CR2 :R2C(OH)–C(O)–R → R2C=O + RCOOH :R2C(OH)–COOH → R2C=O + CO2 These cleavages can be done in the presence of acetic or phosphoric acid at room temperature.
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The plasmids are often coated with some type of adjuvant prior to delivery to enhance the immune response from the host. Linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia (to which the pathogen responsible for Lyme disease belongs), several species of the gram positive soil bacteria of the genus Streptomyces, and in the gram negative species Thiobacillus versutus, a bacterium that oxidizes sulfur. The linear plasmids of prokaryotes are found either containing a hairpin loop or a covalently bonded protein attached to the telomeric ends of the DNA molecule. The adenine-thymine rich hairpin loops of the Borrelia bacteria range in size from 5 kilobase pairs (kb) to over 200 kb and contain the genes responsible for producing a group of major surface proteins, or antigens, on the bacteria that allow it to evade the immune response of its infected host. The linear plasmids which contain a protein that has been covalently attached to the 5’ end of the DNA strands are known as invertrons and can range in size from 9 kb to over 600 kb consisting of inverted terminal repeats.
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The substrate specificity of 5-HEDH has been evaluated in a variety of intact cells and in crude microsome preparations isolated from cultured human blood monocytes differentiated into macrophages. These studies indicate that the enzyme efficiently oxidizes long chain unsaturated fatty acids possessing a hydroxy residue at carbon 5 and a trans double bound at carbon 6 to their corresponding 5-oxo products. It is therefore most efficient in metabolizing 5(S)-HETE to 5-oxo-ETE and, with somewhat lesser efficiency, in metabolizing other 5(S)-hydroxyl-6-trans unsaturated fatty acids such as 5(S)-hydroxy- eicosapentaenoic acid, 5(S)-hydroxy-eicosatrienoic acid, 5(S)-hydroxy- eicosadeinoic acid, 5(S)-hydroxy-eicosamonoenoic acid, 5(S)-hydroxy- octadecadienoic acid, 5(S),15(S)-dihydroxyeicosatetraenoic acid, and the 6-trans isomer of leukotriene B4 (which is a 5(S),12(S)-dihydroxyeicosatetraeonic acid) to their corresponding oxo analogs. 5-HEDH has relatively little ability to oxidize 5(S)-hydroxyl-tetradecadienoic acid, the R stereoisomer of 5(S)-HETE (5(R)-HETE), or a racemic mixture of 8-HETE, and does not oxidize 12(S)-HETE, 15(S)-HETE, leukotriene B4, a racemate mixture of 9-HETE, a racemate mixture of 11-HETE, or a 5(S)-hydroxy-6-trans 12 carbon dienoic fatty acid.
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