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At least 109 records · Page 6Linked to original sources
PubMed1971

Scanning electron microscopic observations of surface structure of isolated human chromosomes.

Isolated human chromosomes dried by the critical-point method have been assumed to retain their original three-dimensional shape when viewed under a transmission electron microscope. Our scanning electron microscopic study confirms this interpretation and reveals an appearance like that of a skein of yarn. The existence of fiber bridges between chromatid pairs and among chromosomes is demonstrated.

Chromosomes↗
PubMed1988

The surface morphology of the endolymphatic sac of the Mongolian gerbil (Meriones unguiculatus) (a scanning electron microscopic study).

A scanning electron microscopic study of the endolymphatic sac of the mongolian gerbil is presented. As described in other animal species and in man, three rather distinct regions on the epithelial surface can also be recognized in this rodent. Light and dark cells are seen to line the sac epithelium throughout. At the level of the intermediate portion, however, a different cell type--the granular cell--is present, with its luminal surface covered by large amounts of solid material. On the basis of light and transmission electron microscopic studies presented elsewhere, a higher degree of functional specialization in this portion of the gerbilline sac is proposed.

Animals↗
PubMed1980

Scanning electron microscope histochemistry: the use of backscattered electrons to identify epidermal Langerhans cells in the scanning electron microscope.

Epidermal sheets reacted for ATPase were examined in the scanning electron microscope and images based on atomic number contrast formed by collecting the backscattered electrons. Langerhans cells lying within the tissue were revealed and could be related to surface structures by reference to conventional secondary electron images.

Adenosine Triphosphatases↗
PubMed1989

A 25% tannic acid solution as a root canal irrigant cleanser: a scanning electron microscope study.

A scanning electron microscope was used to evaluate the cleansing properties of a 25% tannic acid solution on the dentinal surface in the pulp chamber of endodontically prepared teeth. This was compared with the amorphous smear layer of the canal with the use of hydrogen peroxide and sodium hypochlorite solution as an irrigant. The tannic acid solution removed the smear layer more effectively than the regular cleansing agent.

Dental Pulp Cavity↗
PubMed1975

[The enamel-dentin membrane in the scanning electron microscope].

In the scanning electron microscope in detailed structure of the dentino-enamel membrane can be investigated. This membrane is mineralized. After partial demineralization it covers the bottom of prism margins and enables their firm anchoring on the surface of dentin. Here the prism bundles are anchored in dishlike formations, on the bottom of which a network of fibers is found, covered by the dentin-enamel membrane. Through artificial fissures in the membrane the above mentioned network of fibers can be seen.

Bicuspid↗
PubMed1976

Fine structure of schistosome eggs as seen through the scanning electron microscope.

Through a scanning electron microscope the eggs of Schistosoma japonicum were observed to have microvili-like chitinous projections densely distributed and entangled on the surface, each more than 3 mu in length and 0.05 to 0.08 mu in diameter. The microspines of eggs of S. mansoni and S. haematobium were found to be thicker, shorter, and less widespread than were those of S. japonicum eggs, and not entangled. It is noteworthy that such small projections on the surface of schistosome eggs remain erect in the critical point drying procedure.

Female↗
PubMed1975

Preclotting of knitted Dacron prosthesis. A scanning electron microscope study.

A scanning electron microscope study of preclotting on knitted Dacron prosthesis is reported. Five steps of the interaction are well identified: (1) before any blood contact (virgin Dacron), (2) during the first 3 minutes (fibrin and platelet aggregates), (3) fifth minute of contact (clotting), (4) 15 minutes of contact with heparinized blood (thin fibrin network), and (5) the following minutes (invasion of fibrin, which enmeshes blood cells).

Adult↗
PubMed1985

Internal morphology of surface zones from acid-etched caries-like lesions: a scanning electron microscopic study.

Using scanning electron microscopic techniques, we compared the surface topography and internal surface morphology of acid-etched caries-like lesions of enamel with those of sound enamel and caries-like lesions of enamel. The results indicated that acid-etching of caries-like lesions of enamel yielded etching patterns similar to those previously described for sound enamel. The internal morphology of the acid-etched lesion indicated that porosities were created which may allow access to the subsurface demineralized area of the lesion and could prove beneficial in facilitating remineralization.

Acid Etching, Dental↗
PubMedDate not supplied

Software acceleration techniques for the simulation of scanning electron microscope images.

A scanning electron microscope (SEM) simulator was developed based on the models used in the MONSEL software. This simulator extends earlier work by introducing an object-oriented framework and adding optimization methods based on precomputation of electron trajectories. Several optimizations enable speedup by factors of 5-100 on a single processor over unoptimized simulations without introducing additional approximations. The speedup for a particular surface depends on the self-similarity of the surface at the scale of the electron penetration depth. We further accelerate by parallelizing the calculations for a total speedup of about 100-2000 on 30 processors. The goal of this work was to create a system capable of simulating a quantitatively accurate SEM image of a relatively unconstrained surface. Results of this work include simulation software, optimization algorithms, performance measurements with various optimizations, and examples of simulated images.

Algorithms↗
PubMed1980

The evolution of cervical mucus infrastructure in normal cyclic baboons (Papio anubis) and castrated females receiving hormonal supplies. A scanning electron microscope study.

The scanning electron microscope was used to study the evolution of the infrastructure of cervical mucus in normal cyclic baboons and in castrated animals treated with ovarian hormones for establishing an artificial cycle. In both groups, the results make conspicuous the progressive enlargement of the filamentous woof, which attains a maximum at midcycle and then decreases by degrees in the second part of the cycle. It was shown that the evolution of the framework is very similar during normal and artificial cycle, with only variations of slight amplitude. Moreover, the variations in the baboon mucus infrastructure closely resemble those described in the human. The results are briefly discussed in the light of known data.

Animals↗
PubMed1983

Patterns of cilia formation in the lower respiratory tract of the dog: a scanning electron microscopic study.

A scanning electron microscopic study of the distribution of ciliated cells in the tracheobronchial tree of 25 dogs whose ages ranged from four hours to six months was carried out. In newborn puppies, only the dorsal wall of the trachea was completely ciliated while the lateral and ventral walls showed patchy ciliation. This pattern of cilia formation persisted until five days of age when the whole tracheal wall was found to be completely ciliated. The bronchus of newborn puppies was uniformly poorly ciliated but almost complete ciliation was achieved by two days. Likewise, large and small bronchioles of newborn animals had few cilia and, although the number of ciliated cells had increased by two days, complete ciliation was never observed regardless of the age of the dog. No ciliated cells were found in the respiratory bronchioles of any of the 25 dogs.

Age Factors↗
PubMed1986

Patellar chondropathy. II. Ultrastructure, scanning electron microscopic studies.

A scanning electron microscopic study of the chondropathy of the patellar articular surfaces following knee injury was made. The early signs of degeneration were evident in the superficial membrane. Here, the fibres running parallel with the surface then turning deep become irregularly arranged, i.e. the amount of matrix embedding the fibres was reduced and the uncovered fibres became fragmented causing degeneration of the superficial membrane. During the progressive pathological process, as a result of the gradual deterioration of the interterritorial substance of the uncovered hyaline cartilage, spaces, fissures and deep pits were formed in the upper, then the lower, articular layers. The degeneration involved also the chondrons. With the disintegration of the chondrons the external and internal cell areolae disappear, the cell nests of chondrocytes are opened and the cells degenerate. Finally, the irregular cellular and fibrous structures and their remnants as well as the elements of connective tissue proliferation initially associated with the degenerative process can be visualized ultrastructurally.

Cartilage Diseases↗
PubMed1981

Dynamics of endothelial repair in end-to-side microsurgical carotid anastomoses in rats: a scanning electron microscopic evaluation.

A scanning electron microscopic (SEM) investigation of endothelial behavior, following carotid end-to-side microsurgical anastomoses, was carried out in twenty-four Sprague-Dawley rats. From the hemodynamic point of view, the experimental model used in this study involved a bidirectional flow in the recipient vessel. Following surgery, specimens were collected at intervals varying from 15 minutes to 14 days. The thrombus formation was particularly evident in the first 45 minutes, and then gradually disappeared. Evidence showed that the new endothelial cells, covering the defect at the site of the suture, originate from the normal endothelium. Regenerated endothelial cells showed particular morphological features which are expressions of high metabolic rate and of active cell movement. Endothelial repair on the suture line began 3 days after the operation, and was completed there earlier than it was on the stitches. An accurate microsurgical technique is needed to avoid an increased thrombus formation and delayed re-endothelialization.

Animals↗
PubMed1986

The sinusoidal lining cells in "normal" human liver. A scanning electron microscopic investigation.

The scanning electron microscopic was used to study the fenestrations of human liver sinusoids. Thirteen biopsies, where light microscopy and transmission electron microscopy revealed normal sinusoidal architecture, were investigated. The number of fenestrae was calculated in acinar zone 3 and acinar zone 1 areas. The porosity, i.e. fenestrated area relative to total area of the sinusoidal lining wall, was estimated on micrographs by using a Texture Analysing System (TAS). A zonal gradient was found with median 23.5 fenestrae per micron 2 in zone 3, as compared to 19.2 fenestrae per micron 2 in the zone 1 area (p less than 0.005). Increasing porosity towards the terminal hepatic vein was found (9.1% in zone 3 vs. 7.6% in zone 1 (p less than 0.05)). This was due to an increased number of fenestrae measuring 100 nm or less in diameter in zone 3 areas. The number of fenestrae measuring more than 100 nm but less than 300 nm was unchanged along the sinusoids. Fenestrae larger than 300 nm were rare and randomly distributed. The results suggest a different permeability along the sinusoidal lining, which may influence the transport between blood and hepatocytes and thus be of importance to hepatocellular function.

Adult↗
PubMedDate not supplied

Contact angle analysis on polymethylmethacrylate and commercial wax by using an environmental scanning electron microscope.

The environmental scanning electron microscope (ESEM) represents one of the most exciting breakthroughs in electron microscopy since the invention of the electron microscope. Its ability to observe uncoated and hydrated samples enhances the possibility for investigating the wettability of surfaces at a microscopic level; by varying the relative vapour pressure or the temperature inside the chamber, it is possible to condense water drops on a micron scale. A large problem in measuring contact angles by ESEM is that the observation angle is not parallel or perpendicular to the surface; thus, the study of the droplets profile using the common algorithms such as spherical approximation or axisymmetric drop shape analysis (ADSA) is not possible, because only a spherical cap shape is commonly observed. In this paper we provide a useful mathematical model to calculate the real contact angle from the initial images. Initially, some simulated spherical caps with different contact and observation angles were created by an appropriate graphic package in order to test the mathematical model. Some real drops obtained by ESEM on wax and polymethylmethacrylate (PMMA) were then studied and the results compared with contact angles measured by common methods on the same materials.

Journal Article↗
PubMed1996

Comparative morphology of the pectinate ligaments of domestic mammals, as observed under the dissecting microscope and the scanning electron microscope.

The pectinate ligaments of ten horses, two donkeys, five oxen, five sheep, ten goats, five dogs, five cats, thirty pigs and two rabbits were studied under the stereomicroscope and the scanning electron microscope. In the horse and the donkey, the pectinate ligament was very prominent and was characterized by sturdy interconnected strands and relatively small intertrabecular spaces. The pectinate ligaments of ruminants were composed of shorter strands, separated by relatively larger spaces. Fusion between adjacent strands, resulting in the formation of fenestrated sheets, was regularly observed in these species, in particular in the superior and inferior ocular segments. In the dog and the cat, the pectinate ligament consisted of slender strands that were separated by large intertrabecular spaces. The strands of the pectinate ligaments of the pig and the rabbit were shorter and their diameters were intermediate between those of the herbivores and the carnivores. The clinical relevance of the normal variability in the structure of the pectinate ligament and proposals for a uniform anatomical nomenclature are discussed.

Animals↗
PubMed1977

Modified tannin-osmium conductive staining method for non-coated scanning electron microscope specimens. Its application to microdissection scanning electron microscopy of the spleen.

Supplement of guanidine hydrochloride to the original tannic acid solution of MURAKAMI (1973) eliminated, without debilitating the conductivity effect, the vexatious treatment with different amino-acids and sucrose in the previous method (MURAKAMI, 1974). The procedures and advantages of this simplified modification are described using human spleen samples; attempt was made to elucidate the structure of arterial terminals by dissecting the specimens under the scanning electron microscope.

Dissection↗