Appearance Of Pits Research Articles

A scanning electron microscopic study of the dorsal surface of the human tongue.

To study the dorsal surface of the human tongue using a scanning electron microscopy (SEM), tissue specimens were taken from the anterior part of the tongues of 15 individuals aged from 21- to 28-years-old. The formalin-fixed samples were processed routinely for SEM. With SEM the surface of the normal tongue mucosa was shown to be rather evenly covered by filiform papillae, with some fungiform papillae scattered among them. Filiform papillae consisted of two parts: the body and hairs. The mucosal surface of the body was smooth; the squamous epithelial cells were polygonal, and their boundaries were prominent. On the surface of the superficial epithelial cells were parallel or branching microplicae. Each filiform papilla had 6-10 hairs, which were scaled and covered by an extensive plaque of microorganism. The upper surface of the fungiform papillae was smooth; only a few desquamating cells were seen. The superficial cells had a pitted appearance and cell boundaries overlapped. Taste pores, up to 3 pores in a single papilla, were found on the upper surface. Desquamation was more pronounced on the base of the fungiform papillae than on the upper surface. In almost all fungiform papillae some hairs protruded from the base. Parallel microplicae were found on the surface of the superficial cells of the base. The structure and function of the human tongue, as well as the microplicae of its superficial cells, are compared to those of various species of animals.

A role for glutathione and glutathione reductase in control of corneal hydration

We have assessed the importance of the glutathione redox system of the corneal endothelial cells in the control of stromal hydration. The ability of freshly isolated corneas to maintain normal hydration during perfusion, while the activity of glutathione reductase was inhibited with 1,3- bis(2-chloroethyl)-1-nitrosourea (BCNU), was tested under a number of conditions. BCNU at 125 μ m led to mild swelling and at 500 μ m to more severe swelling. Swelling was also severe when 50 μ m H 2O 2 was added together with 125 μ m BCNU. The concentration of total glutathione (GSH + GSSG) in the endothelia of these corneas was decreased and the fraction found in the oxidized form was higher than in controls without BCNU. Glutathione reductase activity was inhibited in the perfused endothelia by 90%. With the addition of 0·5 m m GSSG during perfusion, swelling due to 125 μ m BCNU was at a slightly lower rate and reductase activity was inhibited only 79%. Complete proteetion was afforded against 125 μ m BCNU induced swelling by 1·0 m m GSH, corneas maintaining normal thickness for over 4 hr. The endothelial surface of the perfused corneas was shown by seanning electron microscopy to be little disturbed by the low concentration of BCNU, but at high concentration, or with H 2O 2 added, the cells were collapsed and had a heavily pitted appearance. We conclude that when the cornea is under oxidative stress (e.g. in the presence of H 2O 2) a rapid turnover of endothelial GSH via glutathione reductase and the hexose monophosphate shunt is required. Under conditions of less stress, the reduced need for GSH to counteract oxidative threats can be supplied either exogenously or by the partially inhibited reductase.

High temperature oxidation of iron at 1200 °C in a hot-stage environmental scanning electron microscope

The growth of a wustite scale on pure iron oxidized at 1200 °C and\(P_{O_2 } \cong 10^{ - 4} \) atm was studied in a hot stage environmental scanning electron microscope. Macroscopic ledges for the growth of wustite were seen to evolve from pits at the oxide/gas interface. These pits are anchored by screw dislocations emerging at the surface, and the sides of pits represent oxide planes of low surface energy. The intermittent activity/inactivity of pits may result from the climb of an edge dislocation jog segment to the surface. The passage of an oxide grain boundary through a pit was observed during wustite grain growth. The particular appearance of growth pits, or else of faceted ledges, on different grains is decided by the relative orientations of the nominal surface plane with the lattice planes of low surface energy.

Acid‐etching of enamel cavity walls

Abstract— The acid‐etched patterns produced on enamel cavity walls and the enamel tooth surface were investigated and the implications of these patterns on cavity preparation for composite resin restorations are discussed.The predominant pattern on enamel cavity walls is of obliquely and longitudinally sectioned prisms. Less commonly, cross‐sectioned prisms, prismless enamel and a rough, pitted appearance are observed. Excessive etching (for example, for four minutes) should be avoided.

Development of apical pits in chloride cells of the gills of Pimephales promelas after chronic exposure to acid water

Groups of 12 fathead minnows were exposed for 129 days to Lake Superior water acidified (pH 5.0, 5.5, 6.0 or 6.5) with reagent grade H2SO4 by means of a multichannel toxicant system for flow-through bioassays. Untreated water (pH 7.5) had the following properties: hardness 45.3 ± 0.3 (95% confidence interval) mg/1 as CaCO3; alkalinity 42.6 ± 0.2 mg/1; Cl- 0.03 meq/1; Na+ 0.05 meq/1; K+ 0.01 meq/1; Ca2+ 0.68 meq/1; Mg2+ 0.26 meq/1; dissolved O2 5.8 ± 0.3 mg/1; free CO2 3.2 ± 0.4 mg/1; T= 24.3 ± 0.1°C. The 1st, 2nd and 3rd gills were subsequently processed for LM (methacrylate), TEM and SEM respectively.Three changes involving chloride cells were correlated with increasing acidity: 1) the appearance of apical pits (figs. 2,5 as compared to figs. 1, 3,4) in chloride cells (about 22% of the chloride cells had pits at pH 5.0); 2) increases in their numbers and 3) increases in the % of these cells in the epithelium of the secondary lamellae.

A Study of Inclusions in Indium Phosphide

A detailed examination of unusual inclusions in substrates has been undertaken. Techniques employed have included optical microscopy, scanning electron microscopy, reflection and transmission x‐ray topography, conventional and high voltage electron microscopy, electron diffraction, energy dispersive x‐ray analysis, and Auger emission spectroscopy. Inclusions have been detected in many, but not all, undoped, Fe‐, Sn‐, and Ge‐doped ingots, at densities from ∼103 to 104 cm−2. Larger inclusions consist essentially of a central core of densely tangled dislocations, surrounded by dislocation loops predominantly on {110} planes and extending 10–20 μm outwards from the core. The entire complex of core plus surrounding loops results in a characteristically pitted appearance after etching, or as a region of strong contrast by x‐ray topography. Smaller inclusions (∼1 μm size) have been examined in electron microscope specimens foils. Some inclusions have been found at line dislocations, and it is probable that this is where the majority of inclusions originate, by a nucleation process. Attempts to determine the structure and chemical composition of the inclusions are presented and discussed.

Redistribution of intramembrane particles related to acetylcholine release by cholinergic synaptosomes

Acetylcholine release was measured on suspensions of pure cholinergic synaptosomes, isolated from torpedo electric organ. Transmitter release was triggered by two different methods: KCl depolarization, or action of a venom extracted from a polychaete annelid Glycera convoluta . This venom was known to increase considerably the miniature endplate potential frequency at neuromuscular junctions. Ultrarapid freezing of synaptosomes in suspension in the absence of fixation, followed by freeze fracture, permitted us to show: (1) That the venom does not trigger the appearance of endo-exocytotic pits in the presynaptic membrane, in contrast to KCl depolarization. (2) That both KCl depolarization and venom action lead to a decrease in the number of small P-face intramembrane particles and to an increase in the number of medium-sized E-face particles. In addition, the venom increased the number of medium-sized P-face particles. The redistribution of the intramembrane particles is discussed in relation to the release of transmitter which has been measured in parallel.

Age-embrittlement of glass-reinforced concrete containing blastfurnace slag

Fracture toughness of a Glass Reinforced Concrete (GRC) beam may be defined in terms of the investment of mechanical work required to crack the matrix (U i) and to bring the beam to some defined degree of damage (U f). The ratio (U f−U i)/U i is used as an index of the effective contribution of glass fibre to fracture toughness of the composite. Common experience is that (U f−U i)/U i reduces with age of GRC even if alkali resistant (AR) glass is used. The program was designed to test the postulate that blastfurnace slag (BFS) added as partial replacement for cement or as aggregate would attract sufficient Ca(OH) 2 (CH) to reduce alkali attack of the glass. Tests over a period of 2 years showed that presence of BFS, contrary to expectations, reduced (U f−U i)/U i. Scanning Electron Microscope and Energy dispersive X-Ray studies showed concentrations of CH at the fibre-matrix interface when no blastfurnace slag was used. In all cases whether or not BFS was used, embrittlement coincided with appearance of etch pits in the glass and massive precipitation of CH around glass fibres.

Cortical reaction in inseminated eggs of the horseshoe crab, Limulus polyphemus L

The egg cortical reaction in Limulus polyphemus is described in four events. Approximately 10 min after insemination, small “pits” are visible in the cortex of the inseminated Limulus egg. These pits progressively enlarge, eventually coalesce, and finally disappear, leaving a smooth-appearing surface approximately 60–90 min after insemination. Based on these visible changes, the following four events comprise the cortical reaction: (I) uninseminated egg—smooth surface, (II) inseminated egg—appearance and growth of pits, (III) inseminated egg—coalescence of pits, and (IV) inseminated egg—appearance of smooth surface. Preparation of these events for SEM studies demonstrated morphological characteristics and sequential development of the pits. Also numerous microvilli are found on the surface of uninseminated and inseminated eggs during the cortical reaction. An increase in their diameter during the reaction is particularly unique.

?-FeO (OH) and its solutions

Decomposition products of δ-FeO(OH)-type Fe1−x M x O1−x (OH)1+x phases (M=Mg, Zn, Ca, Cd) have been studied by X-ray diffraction, electron diffraction and high-resolution transmission electron microscopy. It has been shown that the M=Mg and Cd δ-phases decompose to α-Fe2O3-based solid solutions which in turn undergo exsolution to form some MgO and CdO at a higher temperature. In the case of Fe1−x Zn x O1−x (OH)1+x , the decomposition proceeds over α-Fe2O3 ss to an unstable spinel solid solution. All decomposition products are topotactically related to their precursors in the decomposition chain. In the electron microscope some δ-type phases undergo in situ decomposition under intense beam bombardment with somewhat different results than obtained for thermal decomposition products under ambient conditions. The plate-like morphology and crystal size is retained in the decomposition products; however, the products have a more pitted appearance after decomposition.

Scanning electron microscopy of Acholeplasma colonies on agar.

The colony formation and morphology of Acholeplasma laidlawii and of an Acholeplasma species was studied by scanning electron microscopy. In the colonies of both Acholeplasma spp. large irregularly shaped cells, spherical cells, chains of beads, and long filaments with small bulbous distensions were seen. The membrane of some of the large cells seemed to be perforated, giving the cell a pitted appearance.

Surface Textures of Quartz in Tropical Soils

AbstractStudies of the surface textures of quartz grains from a range of tropical soils show the appearance of striations, etch features and dissolution pits, increasing in size and/or quantity in the more weathered soil materials. These features show a crystallographic symmetry, most probably related to the crystallographic orientation of the grain.Monitoring the changes in a 19‐m deep weathering profile on granite showed that physical disintegration begins a few centimeters from the fresh rock. Chemical weathernig, which intensifies towards the soil surface, produces etching and dissolution pits. An additional phenomenon observed is the infusion of clayey materials and/or sesquioxides into the void system of the grains.

Management of inflammatory carcinoma of the breast

Inflammatoryrcinoma of the breast is a clinical entity with no distinct histologic characteristics. The term is derived from the fact that the involved breast shows the cardinal signs and symptoms of inflammation—redness, heat, swelling, and pain. The condition was first described by Lee and Tannenbaum 32 in 1924 and later emphasized by Taylor and Meltzer 33 in 1938 as an uncommon variant of breast cancer. Haagensen's 31 diagnostic criteria are enlargement of the breast, either a distinct breast mass or generalized induration, redness and edema of the mammary skin, and biopsy proof of carcinoma; the redness must involve more than one third of the breast. This type of carcinoma is usually extremely undifferentiated with high-grade malignancy. There is extensive involvement and blockage of the dermal and subdermal lymphatics, resulting in edematous thickening and reddening of the skin, a characteristic pitted appearance known as peau d'orange or pigskin. The disease is

The chewing lesion of the cheeks and lips: its features and prevalence among a selected group of adolescents

A survey among certain population groups in the Cape Province of South Africa revealed 60 chewing lesions of the cheeks and lips. All but 2 of these were found in pupils from reform schools. In these pupils there were 49 lesions among 1098 males and 9 among 157 females. No similar lesions were found in a comparable group of 555 non-institutionalized children. This difference in prevalence was significant at the 5 per cent level. The affected mucosa had a grey-white pitted appearance and could be rubbed off partially. The lesional epithelium was acanthotic with a superficial frayed and necrotic cellular layer. Electron microscopic examination showed a pronounced clustering of organisms on the surfaces of the necrotic superficial cells.

Studies on the soft shell membranes of the egg shell of Chelonia mydas L.

The soft membrane fibres of the turtle eggshell like their avian counterparts, consist of an electron dense core surrounded by a less dense mantle. In the oviposited egg the core material is homogeneously electron dense while in oviducal eggs it has a pitted appearance. Histochemical analyses indicate that as in the fowl, the fibres are a protein-carbohydrate complex.

Changes in the topography of the sea urchin egg after fertilization.

Changes in the topography of the sea urchin egg after fertilization were studied by scanning and transmission electron microscopy. Strongylocentrotus purpuratus eggs were treated with dithiothreitol to modify the vitelline layer and to prevent formation of a fertilization membrane. Dithiothreitol treatment caused the microvilli to become more irregular in shape, length, and diameter than those of untreated eggs. The microvilli were similarly modified by trypsin treatment. This effect did not appear to be due to disruption of cytoskeletal elements beneath the plasma membrane, for neither colchicine nor cytochalasin B altered microvillar morphology. Thus, it appears that the vitelline layer may act in the maintenance of surface form of unfertilized eggs. Since dithiothreitol-treated eggs did not elevate a fertilization membrane, scanning electron microscopy could be used to directly observe modifications in the egg plasma membrane after fertilization. The wave of cortical granule exocytosis initiated at the point of attachment of the fertilizing sperm was characterized by the appearance of pits that subsequently opened, releasing the cortical granule contents and leaving depressions upon the egg surface. The perigranular membranes inserted during exocytosis were seen as smooth patches between the microvillous patches remaining from the original egg surface. This produced a mosaic surface with more than double the amount of membrane of unfertilized eggs. The mosaic surface subsequently reorganized to accommodate the inserted membrane material by elongation of microvilli. Blebs and membranous whorls present before reorganization suggested the existence of an unstable intermediate state of plasma membrane reorganization. Exocytosis and mosaic membrane formation were not blocked by colchicine or cytochalasin B, but microvillar elongation was blocked by cytochalasin B treatment.

The formation of thermal etch patterns during diffusion in Indium antimonide

During the preparation of diffused p-n junctions in indium antimonide the occurrence of non-ideal electrical behaviour was found to be associated with the occurrence of microscopic thermal etch pits. The appearance of such pits is correlated with the gettering action of the Indium used as a solvent and diluent for the cadmium diffusion source. The mechanism of the formation and growth of such features is studied and shown to be a variant of the metallic etching process reported previously.

Etching of Domains and Dislocations in Ferroelectric NaNO2 Crystals

Dislocation etch pits can be formed only on the positive end of the polarization in NaNO2 crystal by ethyl alcohol solution containing a small of amount NaOH. How the concentration of NaOH, NaNO2, and cation of the salt NaOH affect etching process of dislocations, domains, and {121} twins were studied. The positive end etches faster than the negative end in alcohol containing no OH- ion, while in the alcohol solution containing OH- ion the positive end etches slower than the negative end. From the experimental results following conclusions were obtained. (1) The added OH- ion is strongly adsorbed on the positive end of the polarization because of the spontaneous polarization charge, and inhibits the dissolving ions to leave the kink. (2) The adsorption of OH- ions converts the limiting process of dissolution from the volume process to the surface process, resulting in the appearance of dislocation pits.

On discrete saturation of inhomogeneously broadened ESR lines

The saturation by a pulse of an ESR line. the width of which is determined by the nuclei surrounding the magnetic centre, causes the appearance of several pits in the case of a complex super hfs.

Management of Inflammatory Carcinoma of the Breast

Inflammatoryrcinoma of the breast is a clinical entity with no distinct histologic characteristics. The term is derived from the fact that the involved breast shows the cardinal signs and symptoms of inflammation—redness, heat, swelling, and pain. The condition was first described by Lee and Tannenbaum 32 in 1924 and later emphasized by Taylor and Meltzer 33 in 1938 as an uncommon variant of breast cancer. Haagensen's 31 diagnostic criteria are enlargement of the breast, either a distinct breast mass or generalized induration, redness and edema of the mammary skin, and biopsy proof of carcinoma; the redness must involve more than one third of the breast. This type of carcinoma is usually extremely undifferentiated with high-grade malignancy. There is extensive involvement and blockage of the dermal and subdermal lymphatics, resulting in edematous thickening and reddening of the skin, a characteristic pitted appearance known as peau d'orange or pigskin. The disease is