Under its shadow, I watched who the crowd parted for, who they blocked, the nearly ineffable thickenings and thinnings among people.
|
|
There are anterior, posterior, and two lateral thickenings. A septum begins to form between what will later become the ascending aorta and pulmonary tract. As the septum forms, the two lateral thickenings are split, so that the ascending aorta and pulmonary trunk have three thickenings each (an anterior or posterior, and half of each of the lateral thickenings). The thickenings are the origins of the three cusps of the semilunar valves.
|
|
The semilunar valves (the pulmonary and aortic valves) are formed from four thickenings at the cardiac end of the truncus arteriosus. These thickenings are called endocardial cushions. The truncus arteriosus is originally a single outflow tract from the embryonic heart that will later split to become the ascending aorta and pulmonary trunk. Before it has split, four thickenings occur.
|
|
The spores produced are usually spherical or nearly so, with a characteristic double wall structure that features U-shaped thickenings.
|
|
Taenidia (singular: taenidium) are circumferential thickenings of the cuticle inside a trachea or tracheole in an insect's respiratory system. The geometry of the taenidiae varies across different orders of insects and even throughout the tracheae in an individual organism. Taenidia generally take the form of either hoop or spiral thickenings of the tracheal cuticle.
|
|
According to detractors, they are not glands, but mere thickenings of the skin and are not involved in the formation of smegma.
|
|
They disappear at once on slightly relaxing the air-pressure, whilst true incipient thickenings of the surface remain white and unpliably stiff.
|
|
Clypeate grains are either functionally omniaperturate and have a thin exine and uniformly thickened intine or are porate with localized thickenings of intine.
|
|
In the hornworts, elaters are branched clusters of cells that develop in the sporophyte alongside the spores. They are complete cells, usually without helical thickenings (except in the Dendrocerotaceae).
|
|
Gerontic shells thickened along margins, some costae occasionally bifurcating. No smooth areas observed. Interior. — No secondary thickenings present in either valve, structures delicate. No pedicle collar observed in two sectioned specimens.
|
|
Species in this subfamily infect worms of the family Lumbricidae. In these genera syzygy occurs extremely early in the life cycle. The oocyst is navicular or biconical and has unusual thickenings at both ends.
|
|
These shared traits include: tracheids with scalariform pits with tori interspersed with annular thickenings, absence of scalariform pitting in primary xylem, scale-like and strap-shaped leaves of Ephedra and Welwitschia; and reduced sporophylls.
|
|
Merogony generally occurs by budding from surface of meront to form uniformly sized merozoites. The gametes are similar (isogametes) and fuse to form navicular oocysts which have pronounced polar thickenings. The oocysts contain eight (rarely four) sporozoites.
|
|
The secondary walls have thickenings in various forms—as annular rings; as continuous helices (called helical or spiral); as a network (called reticulate); as transverse nets (called scalariform); or, as extensive thickenings except in the region of pits (called pitted). Tracheids provide most of the structural support in softwoods, where they are the major cell type. Because tracheids have a much higher surface to volume ratio compared to vessel elements, they serve to hold water against gravity (by adhesion) when transpiration is not occurring. This is likely one mechanism that helps plants prevent air embolisms.
|
|
Each zygote forms 8 lemon shaped oocysts with polar thickenings. The sporozoites are elongate and attached to the poles of the oocyst. The oocyst leaves the host either via the faeces or after the death of the host and its subsequent disintegration.
|
|
During the anatomical studies, the wall thickenings of the endodermal cells were found to be three-sided. Leaf features, such as papillae, metaxylem number in the root and arrangement of vascular bundles can be used as distinguishing characters for the Iris species.
|
|
The endocardial cushions are thought to arise from a subset of endothelial cells that undergo epithelial-mesenchymal transition, a process whereby these cells break cell-to-cell contacts and migrate into the cardiac jelly (towards the interior of the heart tube). These migrated cells form the "swellings" called the endocardial cushions seen in the heart tube. Upon sectioning of the heart the atrioventricular endocardial cushions can be observed in the lumen of the atrial canal as two thickenings, one on its dorsal and another on its ventral wall. These thickenings will go on to fuse and remodel to eventually form the valves and septa of the mature adult heart.
|
|
Heavy infections are thought to lead to gastrointestinal disturbances that might cause emaciation. Nematodes are generally in the lumena of the gastric glands. Catarrhal gastritis may result which will eventually lead to chronic hypertrophic gastritis. The typical mucosal surface is characterized by irregular circumscribed wart-like thickenings with a finely verrucose surface.
|
|
Page, RC; Schroeder, HE. "Pathogenesis of Inflammatory Periodontal Disease: A Summary of Current Work." Lab Invest 1976;34(3):235-249 Scar tissue lacks rete pegs and scars tend to shear off more easily than normal tissue as a result. Also known as papillae, they are downward thickenings of the epidermis between the dermal papillae.
|
|
The bacteria group together in a characteristic way, which has been described as the form of a "V", "palisades", or "Chinese characters". They may also appear elliptical. They are aerobic or facultatively anaerobic, chemoorganotrophs. They are pleomorphic through their lifecycles, they occur in various lengths, and they frequently have thickenings at either end, depending on the surrounding conditions.
|
|
The inflammation may cause a serofibrinous pericardial exudate described as "bread-and-butter" pericarditis, which usually resolves without sequelae. Involvement of the endocardium typically results in fibrinoid necrosis and wart formation along the lines of closure of the left-sided heart valves. Warty projections arise from the deposition, while subendocardial lesions may induce irregular thickenings called MacCallum plaques.
|
|
As a young vascular plant grows, one or more strands of primary xylem form in its stems and roots. The first xylem to develop is called 'protoxylem'. In appearance protoxylem is usually distinguished by narrower vessels formed of smaller cells. Some of these cells have walls which contain thickenings in the form of rings or helices.
|
|
In late 1962 and early 1963, Hepler tested the newly developed procedure using a glutaraldehyde pre-fix followed by an osmium post-fix to study plant cell structure using an electron microscope. Building on the earlier work by Sinnott and Bloch, who had shown that wounding the existing tracheary elements in a Coleus stem induced neighboring parenchyma cells to differentiate into new tracheary elements, Hepler showed that cytoplasmic microtubules were localized specifically in the cortical cytoplasm immediately over the bands of new secondary wall thickenings. Moreover, Hepler discovered that the microtubules were oriented parallel to the cellulose microfibrils of the newly formed secondary wall thickenings. This work, along with the studies of Ledbetter and Porter and Green established the importance of cortical microtubules in controlling the alignment of cellulose microfibrils in the cell wall.
|
|
In the internodal region, the Schwann cell has an outer collar of cytoplasm, a compact myelin sheath, and inner collar of cytoplasm, and the axolemma. At the paranodal regions, the paranodal cytoplasm loops contact thickenings of the axolemma to form septate –like junctions. In the node alone, the axolemma is contacted by several Schwann microvilli and contains a dense cytoskeletal undercoating.
|
|
The fourth lower premolar is submolariform. A metaconid is lacking, although on some teeth slight thickenings of the enamel are present in this region. Talonid cusps are slightly differentiated. The first and second lower molars are approximately the same length (M1, average length x=- 1.93 mm, N- 13; M2, x=2.00 mm, N- 9); M. is longer (x= 2.32 mm, N -7).
|
|
The sporangia, which were about in diameter, had spines like the stems, and split (dehisced) along their margin to release the trilete spores, which were in diameter. Vascular tissue was present in the stems, with tracheids having annular, spiral thickenings., p. 254 D. longistipa somewhat resembles Sawdonia, but differs in branching pattern and in the arrangement of the sporangia, including their long stalks.
|
|
It consists of pale yellow intertwined hyphae that are difficult to distinguish individually, and without remains of a gelatinous matrix. Fruit bodies may persist for several months after they have dried. The thick-walled spores are roughly spherical, rusty- brown, finely and densely warted, and have diameters of 5–6.5 µm. Elaters are 50–80 by 4–6 µm, and have ring-like or spiral thickenings.
|
|
Most arachnids lack extensor muscles in the distal joints of their appendages. Spiders and whipscorpions extend their limbs hydraulically using the pressure of their hemolymph. Solifuges and some harvestmen extend their knees by the use of highly elastic thickenings in the joint cuticle. Scorpions, pseudoscorpions and some harvestmen have evolved muscles that extend two leg joints (the femur-patella and patella-tibia joints) at once.
|
|
Peyer's patches are observable as elongated thickenings of the intestinal epithelium measuring a few centimeters in length. About 100 are found in humans. Microscopically, Peyer's patches appear as oval or round lymphoid follicles (similar to lymph nodes) located in the mucosa layer of the ileum and extend into the submucosa layer. The number of Peyer's patches peaks at age 15–25 and then declines during adulthood.
|
|
In the liverworts, elaters are cells that develop in the sporophyte alongside the spores. They are complete cells, usually with helical thickenings at maturity that respond to moisture content. In most liverworts, the elaters are unattached, but in some leafy species (such as Frullania) a few elaters will remain attached to the inside of the sporangium (spore capsule). Spores and two elaters of the liverwort Ptilidium.
|
|
All species are herbaceous or semi-woody and possess a fruit dehiscence type that is unique for the family; the splitting into one persistent and one deciduous valve allows recognizing the genus at first glance. In habit, Virectaria strongly resembles African Hedyotideae such as Otomeria and Parapentas but it lacks some diagnostic features of that tribe, viz. raphides, articulate hairs, heterostylous flowers and exotestal cells with only slight thickenings.
|
|
Globigerinids are characterized by distinctly perforate planispiral or trochospiral tests composed of lamellar radial hyaline (glassy) calcite, with typically globular chambers and single interiomarginal aperture. Some however have multiple or auxiliary apertures, and in some the aperture is areal or terminal in location. Some, also, have keels, reinforcing thickenings along exterior angles. An adaptation to the planktonic habit is the development of long narrow spines that support a frothy buoyant ectoplasm.
|
|
In humans, milk lines form as thickenings of the epidermis of the mammary ridge, along the front surface of both sexes of mammals. Milk lines appear in the seventh week of embryonic development before human sexual differentiation, which explains why male humans have nipples. After initial development of the milk lines they go into remission. Most humans have two nipples, but in some cases more than two will develop.
|
|
The central cells of apical and dorsal laminae are unistratose and smooth, up to 12 micrometres wide, hexagonal-rhomboidal shaped with thin walls and no marginal thickenings. # The dorsal lamina is the section of the leaf edge opposite the sheathing part and the ventral lamina, extending the total length of the leaf on the backside of the costa. Dorsal lamina is not decurrent, mostly decreased to extinction at the leaf base.
|
|
Both limbs of the loop of Henle are lined with the simple squamous epithelium. Their main function is to regulate the levels of water and solutes in the primary urine. The basement membrane of the thin limb in humans has very uniform nodular thickenings that form a network that surrounds the tubule and acts as a support structure that is homologous to the collenchyma in plants. Smith, RA et al.
|
|
Genital pores are unilateral, and each mature segment contains three testes. After apolysis, gravid segments disintegrate, releasing eggs, which measure 30 to 47 µm in diameter. The oncosphere is covered with a thin, hyaline, outer membrane and an inner, thick membrane with polar thickenings that bear several filaments. The heavy embryophores that give taeniid eggs their characteristic striated appearance are lacking in this and the other families of tapeworms infecting humans.
|
|
The sporophytes grow outwards rather than upwards, and like Megaceros, there are no stomata on the surface of the sporophyte. The elater cells do not grow helical thickenings. A number of classification systems place Notothylas in its own order Notothyladales (frequently misspelled Notothylales in the literature). This classification is based on the assumption that the unique physical characteristics of the genus reflect an early divergence from other hornworts.
|
|
Primary xylem is exarch upon maturation, with protoxylem strands positioned around the tips of the primary xylem arms. No differentiation between fascicular and interfascicular regions of the secondary xylem is apparent, and ray cells are rarely observed. Protoxylem tracheids have helical wall thickenings, whereas the tracheids of meta- and secondary xylem possess scalariform and/or bordered pits. All R. songziensis axes bear trichomes or spines, some up to 2.8 mm long.
|
|
In fact, species of Allopseudaxine have a large body tapering anteriorly, and a unilateral, oblique haptor, (which means that they have a single oblique row of clamps,) giving them a triangular appearance. By this triangular shape, they resemble Allopseudaxine. However, species of Allopseudaxinoides can be distinguished from Allopseudaxine by a complete absence of vaginae or the presence of rudimentary ones, the presence of thickenings of clamps capsule, and an accessory clamp sclerite.
|
|
The otic placode visible on this sketch of a developing embryo. After implantation, around the second to third week the developing embryo consists of three layers: endoderm, mesoderm and ectoderm. The first part of the ear to develop is the inner ear, which begins to form from the ectoderm around the 22nd day of the embryo's development. Specifically, the inner ear derives from two thickenings called otic placodes on either side of the head.
|
|
Roussea simplex is a liana of 4–6 m high. The wood vessels have very oblique oval openings which are subdivided by about 20 (maximally 50) bars (this is called scalariform), while the side walls have pits in rows and lack spiral-shaped thickenings. Its young stems are firm and have thick nodes. Leaves are set opposite to each other, but several pairs can be close to each other creating a whorl-like cluster.
|
|
Journal of Natural History, 24 (4): 801-937. doi:10.1080/00222939000770571 In Petalomonas, cells are covered with approximately a dozen thickly, fused pellicle strips making the cell very rigid and possibly resistant to surface ice crystal formation that can disrupt the cell. These pellicle strips, unlike most euglenoids, are lacking grooves or troughs; however, species specific pellicle features, such as pleat-like thickenings at the joints of pellicle strips, that characterize P. cantuscygni, can distinguish certain species.
|
|
Functionally, protoxylem can extend: the cells are able to grow in size and develop while a stem or root is elongating. Later, 'metaxylem' develops in the strands of xylem. Metaxylem vessels and cells are usually larger; the cells have thickenings which are typically either in the form of ladderlike transverse bars (scalariform) or continuous sheets except for holes or pits (pitted). Functionally, metaxylem completes its development after elongation ceases when the cells no longer need to grow in size.
|
|
Dr. John Caffey (1895–1978) first described infantile cortical hyperostosis in 1945. He described a group of infants with tender swelling in the soft tissues and cortical thickenings in the skeleton, with onset of these findings during the first 3 months of life. Dr. Caffey was regarded throughout the world as the father of pediatric radiology. His classic textbook, Pediatric X-Ray Diagnosis, which was first published in 1945, has become the recognized bible and authority in its field.
|
|
Battarrea is a genus of mushroom-producing fungi. The genus used to be classified in the family Tulostomaceae until molecular phylogenetics revealed its affinity to the Agaricaceae. Species of Battarrea have a peridium (spore sac) that rests atop an elongated, hollow stipe with a surface that tends to become torn into fibrous scales. Inside the peridium, the gleba consists of spherical, warted spores, and a capillitium of simple or branched hyphal threads that have spiral or angular thickenings.
|
|
It features dark lime tubercles only on the dehiscence lines. A capillitium is less developed and is composed of pale purple-brown, slim, vermiculated strands, which are overgrown on the peridia. On low magnification, the 1 to 1.5 µm thick strands look like string of pearls. On high magnification, there are from the centre of the strand on cup or pear-shaped links visible, which thickenings are slightly darker on the blunted end, but the stipes are sallow.
|
|
The Involutinidae are a family of foraminiferaOnly Six Kingdoms of Life Cavalier-Smith, 2004 included in the Involutinida, characterized by calcareous tests consisting of an undivided planispirally to trochospirally coiled tubular second chamber wound around the initial proloculus, and which may have thickenings or nodes on one or both sides. This family includes four subfamilies, Aulotortinae, Involutininae, Triadodiscinae, and Triasininae.Involutinidae Loeblich & Tappan 1988 in GSI e-book The Involutinidae were previously included in the Treatise on Invertebrate Paleontology Part C, 1964.
|
|
The calyx consists of five or more sepals, which are often persistent in the fruiting stage, and the corolla is five-merous, rarely numerous. Plants in Theaceae are multistaminate, usually with 20-100+ stamen either free or adnate to the base of the corolla, and are also distinctive because of the presence of pseudopollen. The pseudopollen is produced from connective cells, and has either rib-like or circular thickenings. The ovary is often hairy and narrows gradually into the style, which may be branched or cleft.
|
|
Chancelloriids probably lived on muddy sea-floors, as their sclerites increase in size from the bottom to the top, and all had thickenings at the bases, which are regarded as anchors; they are often preserved in attachment to other organisms or shelly debris. They were very likely filter- feeders. Since the sclerites were external and non-interlocking, they could not have functioned as supporting "struts". Since the body was sessile and attached to the sea-bed, the sclerites would not have aided locomotion by increasing traction.
|
|
The epidermis primarily consists of keratinocytes (proliferating basal and differentiated suprabasal), which comprise 90% of its cells, but also contains melanocytes, Langerhans cells, Merkel cells, and inflammatory cells. Epidermal thickenings called Rete ridges (or rete pegs) extend downward between dermal papillae.TheFreeDictionary > rete ridge Citing: The American Heritage Medical Dictionary Copyright 2007, 2004 Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. The epidermis itself has no blood supply and is nourished almost exclusively by diffused oxygen from the surrounding air.
|
|
Hardwoods have a more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods is the presence of pores, or vessels.CRC Handbook of Materials Science, Vol IV, pg 15 The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall, such as spiral thickenings. As the name suggests, the wood from these trees is generally harder than that of softwoods, but there are significant exceptions.
|
|
In the embryo, the nasal region develops from neural crest cells which start their migration down to the face during the fourth week of gestation. A pair of symmetrical nasal placodes (thickenings in the epithelium) are each divided into medial and lateral processes by the nasal pits. The medial processes become the septum, philtrum, and premaxilla. The first ossification centers in the area of the future premaxilla appear during the seventh week above the germ of the second incisor on the outer surface of the nasal capsule.
|
|
Outside this inner cortex is a hollow middle cortex and a thin outer cortex; sometimes a connection extends from the inner cortex to the outer cortex. The primary xylem of Stigmaria is endarch and arranged in a series of bands surrounded by vascular cambium. The secondary xylem tracheids are arranged in radial lines and contain scalariform wall thickenings with fimbrils identical to those in the aerial branches. No secondary phloem has been found in Stigmaria fossil specimens, and the vascular cambium was unifacial with translocation enabled by the primary phloem.
|
|
The endoperidium consists of densely interwoven hyphae that are 3–9 µm in diameter and walls less than 1 µm thick; they are septate, branched, pale yellow, with clamp connections. The gleba is largely made up of two types of threads. The pseudocapillitium has hyphae up to 5 µm diameter, mostly thin walled, smooth, septate, sparsely branched, hyaline to pale yellow, with clamps. The elaters have diameters of 3.5–7 µm and are 32–70 µm long; they are pale yellow, smooth-walled, tapered and cylindrical with spiral thickenings.
|
|
In the developing heart, the truncus arteriosus and bulbus cordis are divided by the aortic septum. This makes its appearance in three portions. # Two distal ridge-like thickenings project into the lumen of the tube; these increase in size, and ultimately meet and fuse to form a septum, which takes a spiral course toward the proximal end of the truncus arteriosus. It divides the distal part of the truncus into two vessels, the aorta and pulmonary artery, which lie side by side above, but near the heart the pulmonary artery is in front of the aorta.
|
|
Xylodryadella is a monotypic moth genus in the family Xyloryctidae described by Thomas Bainbrigge Fletcher in 1940. Its only species, Xylodryadella cryeranthes, was described by Edward Meyrick in 1925 and is found in New Guinea. The wingspan is about 31 mm. The forewings are rather light brown, with some scattered, blackish scales, the veins partially marked with black streaks and the costa slenderly blackish from the base to beyond the middle, with four irregular projections or thickenings, beneath this irregular whitish suffusion extended as a costal patch to three-fourths and then beneath the costa to near the apex.
|
|
On the underside of the vertebrae of the neck there is a depression with at the mid-line a ridge. The vertebrae of the back have below their front extensions, the prezygapophyses, a groove which is divided in three smaller depressions. The middle vertebrae of the back have a second ridge extending from the base of the upper rib joint, the diapophysis, to the back of the vertebra. In the arm, the shaft of the humerus is reinforced by powerful, somewhat obliquely placed, thickenings extending towards the condyles of the lower joint, which swellings have a hollow front edge.
|
|
A cladogram published in 2004 by Crane et al. places Nothia in a paraphyletic stem group of broadly defined "zosterophylls", basal to the lycopsids (living and extinct clubmosses and relatives). A detailed study of Nothia aphylla questions this positioning of the genus, concluding that its taxonomic placement remains unclear, and that the cladistic analyses of Kenrick and Crane (on which the above cladogram is based) have ignored "fundamental differences" between different kinds of emergences (protrusions from stems). Features of the vascular tissue of typical zosterophylls, such as characteristic thickenings of the cells which conduct water, are also absent in Nothia.
|
|
The name of the genus comes from the Greek word ptilidion for "small feather", in reference to the multiply deeply divided leaves with fringed edges, which give the plant a "feathery" appearance. Unlike other leafy liverworts, the underleaves are not significantly smaller than the lateral leaves. The "flossy" appearance from the leaf edges, together with the characteristic yellowish-brown or reddish-brown color make the genus easy to recognize. Like Ptilidium, Blepharostoma and Trichocolea have deeply divided leaves with marginal cilia, however Ptilidium differs from these other two genera in that its leaf cells have bulging trigones (thickenings at the corners between cell walls).
|
|
These viruses were isolated from and are thought to cause a progressively debilitating cutaneous and mucocutaneous papillomatosis and carcinomatosis syndrome.Woolford L, Rector A, Van Ranst M, Ducki A, Bennett MD, Nicholls PK, Warren KS, Swan RA, Wilcox GE, O'Hara AJ (2007) A novel virus detected in papillomas and carcinomas of the endangered western barred bandicoot (Perameles bougainville) exhibits genomic features of both the Papillomaviridae and Polyomaviridae. J Virol 81(24):13280-13290 The lesions that occur in this disease are irregular thickenings and masses over the skin of the digits, body, pouch, and mucocutaneous junctions of the lips and conjunctiva. Cases have been described in both captive and wild individuals.
|
|
Combinations of cold water-soluble carboxymethylated starch, guar gum and tamarind derivatives are most commonly used today in disperse screen printing on polyester. Alginates are used for cotton printing with reactive dyes, sodium polyacrylates for pigment printing, and in the case of vat dyes on cotton only carboxymethylated starch is used. Formerly, colours were always prepared for printing by boiling the thickening agent, the colouring matter and solvents, together, then cooling and adding various fixing agents. At the present time, however, concentrated solutions of the colouring matters and other adjuncts are often simply added to the cold thickenings, of which large quantities are kept in stock.
|
|
Ventral view with hyperiid amphipod Almost entirely transparent and colorless, and sometimes difficult to resolve, Aequorea victoria possess a highly contractile mouth and manubrium at the center of up to 100 radial canals that extend to the bell margin. The bell margin is surrounded by uneven tentacles, up to 150 of them in fully-grown specimens. The tentacles possess nematocysts that aid in prey capture, although they have no effect on humans. Specimens larger than 3 cm usually possess gonads for sexual reproduction, which run most of the length of the radial canals and are visible in the photos in this article as whitish thickenings along the radial canals.
|
|
As one of the first species selected in the genus Auxarthron, A. californiense was first isolated from pack rat dung in 1963, at California. The genus Auxarthron was erected by Orr and Kuehn to accommodate species with swollen septa of the peridial hyphae, formerly classified in genus of Gymnoascus. However, both Apinis(1964) did not accept this new genus, because they could also observe swollen septa in other species of Gymnoascus. Although this feature may not be significant for distinguishing new genera, the genus Auxarthron could also be identified on the basis of the presence of wall thickenings in the vicinity of septa which they called "knuckle joints".
|
|
The sporophyte had bare stems (axes) up to 20 cm high and about 2 mm in diameter with an undivided cortex. Stomata were present but rare. There was a thin central strand of conducting tissue, but this was not reinforced with spiral and reticulate thickenings and thus does not constitute true vascular tissue. Early stages of development of the sporophytes of Horneophyton (as of hornworts) may have been dependent on their parent gametophytes for nutrition, but mature specimens have expanded, corm-like bases to their stems, up to 6 mm in diameter, that bore rhizoids and appear to be anchored in soil, suggesting a capacity for independent existence after the gametophyte had degenerated.
|
|
They are marked by many well-developed, regular, rounded, toward the aperture slanting axial ribs, of which twenty occur upon the second, twenty-four upon the fifth, and thirty upon the penultimate whorl. These ribs are somewhat thickened at their posterior extremity and give the summits of the whorls a beaded appearance. The intercostal spaces are a little wider than the ribs, crossed by many incised spiral lines, which are about as wide as the raised spaces between them. These incised spiral lines are a little less strongly developed on the posterior portion of the whorls, where the ribs are thickened, but anterior to these thickenings they are very regular and regularly-spaced.
|
|
The altered coat of the arterioles, consisting of adenoid tissue, presents here and there thickenings of a spheroidal shape, the white pulp. The arterioles end by opening freely into the splenic pulp; their walls become much attenuated, they lose their tubular character, and the endothelial cells become altered, presenting a branched appearance, and acquiring processes which are directly connected with the processes of the reticular cells of the pulp. In this manner the vessels end, and the blood flowing through them finds its way into the interstices of the reticulated tissue of the splenic pulp. Thus the blood passing through the spleen is brought into intimate relation with the elements of the pulp, and no doubt undergoes important changes.
|
|
Xylem is a complex vascular tissue composed of water-conducting tracheids or vessel elements, together with fibres and parenchyma cells. Tracheids MT Tyree; MH Zimmermann (2003) Xylem structure and the ascent of sap, 2nd edition, Springer-Verlag, New York USA are elongated cells with lignified secondary thickening of the cell walls, specialised for conduction of water, and first appeared in plants during their transition to land in the Silurian period more than 425 million years ago (see Cooksonia). The possession of xylem tracheids defines the vascular plants or Tracheophytes. Tracheids are pointed, elongated xylem cells, the simplest of which have continuous primary cell walls and lignified secondary wall thickenings in the form of rings, hoops, or reticulate networks.
|
|
Roughly speaking, crystalline cohomology of a variety X in characteristic p is the de Rham cohomology of a smooth lift of X to characteristic 0, while de Rham cohomology of X is the crystalline cohomology reduced mod p (after taking into account higher Tors). The idea of crystalline cohomology, roughly, is to replace the Zariski open sets of a scheme by infinitesimal thickenings of Zariski open sets with divided power structures. The motivation for this is that it can then be calculated by taking a local lifting of a scheme from characteristic p to characteristic 0 and employing an appropriate version of algebraic de Rham cohomology. Crystalline cohomology only works well for smooth proper schemes.
|
|
They may be erect and flat or sometimes less open. The labellum is simple or very slightly lobed, usually very wide and showy without salient calli although normally showing more or less subtle keeled thickenings close to the base, usually of different colors; it is much larger and wider than the other segments, often flat but in M. candida embraces the column and in all species it is slightly fused to the column at their bases. The short column does not have a foot and presents two lateral auricles sometimes merged to each other through a fringe that surrounds the superior edge of the clinandrium. The anther is apical and bears two yellow hard pollinia.
|
|
Programmed cell death in plants has a number of molecular similarities to animal apoptosis, but it also has differences, the most obvious being the presence of a cell wall and the lack of an immune system that removes the pieces of the dead cell. Instead of an immune response, the dying cell synthesizes substances to break itself down and places them in a vacuole that ruptures as the cell dies. In "APL regulates vascular tissue identity in Arabidopsis", Martin Bonke and his colleagues had stated that one of the two long-distance transport systems in vascular plants, xylem, consists of several cell-types "the differentiation of which involves deposition of elaborate cell-wall thickenings and programmed cell-death." The authors emphasize that the products of plant PCD play an important structural role.
|
|
The jugum is more highly developed in some other Polyneoptera, as in the Mantidae. In most of the higher insects with narrow wings the vannus becomes reduced, and the vannal fold is lost, but even in such cases the flexed wing may bend along a line between the postcubitus and the first vannal vein. The Jugal Region, or Neala, is a region of the wing that is usually a small membranous area proximal to the base of the vannus strengthened by a few small, irregular veinlike thickenings; but when well developed it is a distinct section of the wing and may contain one or two jugal veins. When the jugal area of the forewing is developed as a free lobe, it projects beneath the humeral angle of the hindwing and thus serves to yoke the two wings together.
|
|
Endoscopic inspection and biopsy of lesions and endoscopic-based ultrasound inspection of the upper GI tract show lesions, most often in the stomach's pyloric antrium, that are superficial mucosal erosions, shallow ulcers, nodules, enlarged rugae, and/or thickenings of the stomach wall. The histopathology of primary gastric MALT lesions and the marker proteins and genomic abnormalities expressed by the malignant cells in these lesions are given in the Histopathology section. Primary gastric EMZL is associated with infection of the stomach with Helicobacter pylori in >80% of cases or with Helicobacter heilmannii sensu lato in <1% of cases. Indications that gastric Helicobactor pylori is the causes for gastric EMZL include: a positive urea breath test; a positive stool test that detects an antigen of the pathogen in the patient's feces; a positive urease test in a biopsied tissue specimen; a positive serum or whole blood test using specific antibodies directed against the pathogen; and growth of the pathogen in tissue cultures of a biopsied tissue. Helicobacter heilmannii sensu lato designates at least 11 different Helicobactor species of which 5 are known to infect the human stomach.
|
|