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Results for “scanning electron microscope”

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At least 415 records · Page 23Linked to original sources

PubMed1994

Shear bond strength and scanning electron microscopic observation of six current dentinal adhesives.

This paper presents shear bond strength data and scanning electron photo micrographs of six dentinal adhesives: All-Bond 2, etched and unetched; Syntac; Prisma Universal Bond 3; Scotchbond Multi-Purpose; Tenure Solution; and Adhesive By Choice. The methods used in tooth treatment and scanning electron microscopic observation were identical to those used in previous studies. This permitted comparisons among a total of 13 dentinal adhesives (seven from previous studies), all treated under the same experimental conditions and all currently available to the practitioner. Scanning electron micrographs showed the types of failures that occurred when the composite resin was fractured from the dentin. Most of the fractures were adhesive, with the exception of Scotchbond Multi-Purpose, which had many cohesive failures in the dentin or the composite resin. There was no significant difference among any of the shear bond strength values with the exception of Scotchbond Multi-Purpose, which was significantly stronger than the other five adhesives studied.

Analysis of Variance↗

PubMed1993

Scanning electron microscopic study of Trichinella pseudospiralis muscle phase after modulation of host response using an immunostimulant drug.

In a previous study, evident collagen deposition around T. pseudospiralis larvae was noticed after administration of Levamisole to infected mice. The present investigation was undertaken to confirm these findings. Scanning electron microscopic examination revealed multiple clear cystic formations on the surface of the diaphragm muscle. The present investigation was undertaken to confirm these findings. Scanning electron microscopic examination revealed multiple clear cystic formations on the surface of the diaphragm muscle. The presence of such structures was seen to be more frequent when the drug was given as early as the 6th day post infection. Membrane like structure was observed around T. pseudospiralis larvae, an interesting finding which was by far not reported before.

Animals↗

PubMedDate not supplied

Scanning electron microscopic observations on micro-organisms in the root nodules of Tribulus terrestris L. (Zygophyllaceae).

Scanning electron microscopic observations were made on the micro-organisms of root nodules of Tribulus terrestris L. The results showed that nodules of T. terrestris contained dual infection consisting of Rhizobium sp. and Newmania karachiensis. Based on these observations, T. terrestris should be grouped with nonlegume Parasponia-type bacterial nodules.

Bacteria↗

PubMed1986

Scanning electron microscopic study of precancerous and cancerous pancreatic lesions induced by N-nitrosobis (2-oxopropyl) amine in Syrian golden hamsters.

Sequential alteration of Syrian golden hamster pancreatic ducts and ductules was investigated by scanning electron microscope during and subsequent to 10 weekly subcutaneous injections of N-nitrosobis (2-oxopropyl) amine (BOP). By examining surface morphology of ductal cells and resin casts of the secretory branches arising from the common duct, a series of lesions ranging from slight derangement of the luminal dimensions and loss of cilia to marked projections of "finger-like" processes accompanied by pleomorphism at the cellular and microvilli levels and increase in numbers of goblet cells could be established. A ductal histogenesis is proposed on the basis of the present scanning electron microscopic and earlier light microscopic findings.

Animals↗

PubMed1999

Edge Sharpening for Unbiased Edge Detection in Field Emission Scanning Electron Microscope Images.

: We report here a specific type of edge strength anisotropy observed in field emission scanning electron microscope (FESEM) images. The images show weaker edge gradients in the scanning direction and hence these edges frequently go undetected. Direct application of edge detection algorithms to images with nondistinct edges, such as powder particles, show strong bias to edges perpendicular to the scanning direction. Edge orientation polarograms obtained from these images always show strong fictitious particle orientation in the scanning direction. In this work, we discuss an edge-sharpening algorithm that corrects for this bias and results in relatively more accurate and consistent edge orientation information.

Journal Article↗

PubMed1983

Crystalloids in salivary duct cysts of the human parotid gland. Scanning electron microscopical study with electron probe X-ray microanalysis.

Crystalloids found in salivary duct cysts of the human parotid gland were examined by scanning electron microscopical observations with electron probe X-ray microanalysis. The cystic spaces were filled with numerous crystalloids which had a variety of forms with slight eosinophilic and glassy appearance. Scanning electron microscopically, crystalloids were hexagonal and rhombohedral in shape, and cutting the surface showed a polycyclic structure or regular parallel lamination. By electron probe X-ray microanalysis, sulphur was the only detected element. The present study suggests that crystalloids resulted from deposition from supersaturated saliva containing sulphur containing compounds into the cystic lumen or into epithelial cytoplasm.

Crystalloid Solutions↗

PubMed1986

Functional scanning electron microscopical observations on the oral roof in an air-breathing teleost, Clarias batrachus (LINN.).

Scanning Electron Microscopical (SEM) as well as light microscopical features of the oral roof including barbels of the air-breathing teleost, Clarias batrachus (LINN.) have been described in relation to its feeding habit. 3 distinct types of taste buds have been recorded for the first time in the barbels, lip, and in and around the teeth bearing suprapharyngeal teeth pad of the fish studied. The taste buds in the barbels and lip are elevated over the epithelium and confer wart like appearance which probably help in mechanoreception in addition to chemoreception. The taste buds in the suprapharyngeal teeth pad slightly rise above the epithelium whereas those in the borders of it do not. They also possess numerous minute papillae in the gustatory pores. These taste buds seem to act as chemoreceptors. SEM and light microscopical observations on the structure and distribution of taste buds in the oral roof clearly reveal that the fish is purely a taste-feeder and scans and gropes the food materials from the bottom of the pond.

Animals↗

PubMed1981

[Alternations of dermal lymphocytes in mycosis fungoides, a study with the scanning electron microscope (author's transl)].

Isolated dermal lymphocytes from the infiltrate of mycosis fungoides show on scanning electron microscopic examination following characteristics, which differ from normal lymphocyte surface: loss of the round cell shape, increase of absolute length of microvilli, increase of lymphocytes with smooth surface and mitoses. These alterations concern all immunologic subpopulations and may indicate a stimulation of the whole dermal infiltrate in mycosis fungoides.

Cell Membrane↗

PubMed1989

Scanning electron microscopic study of hemodynamically induced tears in the internal elastic lamina of rabbit arteries.

A scanning electron microscopic investigation of tears in the internal elastic lamina of the afferent artery of experimental arteriovenous fistulae was undertaken to determine their site of initiation and to elucidate their nature. Carotid-jugular arteriovenous fistulae and contralateral common carotid arteriotomies were performed in rabbits sacrificed from two to 63 days post-operatively. Following de-endothelialization, scanning electron microscopy of the internal elastic lamina revealed predominantly transverse straight tears with sharp margins. Even in chronic fistulae the tears retained their sharp margins despite their propagation. No evidence of repair was observed. The tears commenced by rupture of the elastic trabeculae traversing the fenestrae. Enzymatic digestion of the internal elastic lamina did not resemble the hemodynamically induced tears and no evidence of elastolytic enzyme activity was detected. The tears suggest that the abnormally stressed elastic tissue has undergone some structural alteration leading to a reduction in its tensile strength.

Animals↗

PubMed1979

Middle ear mucosa in cleft palate children. A scanning electron microscopic study.

Twenty-three promontory mucosal specimens from cleft palate children were studied by scanning electron microscope. Comparative studies were made, using light and transmission electron microscopy. The mucosal lining was pseudostratified columnar with microvilli, a few ciliated cells with secretory granules and numerous goblet cells. A few mucous glands, could be seen in certain areas. Microvilli with bulging tips and cilia with microknobs were common phenomena. The submucosa were inflamed, with leukocytes, macrophages, plasma cells and lymphocytes, indicating the presence of both cellular and humeral defence mechanisms.

Child↗

PubMed1985

Scanning electron microscope study of the lung in drowning.

The authors describe the results obtained using the scanning electron microscope (SEM) to study drowned lungs and control lungs. Results are compared with a previous study carried out using laboratory animals. The results from both studies are analogous, in the absence of chronic pulmonary emphysema. The diagnosis of chronic pulmonary emphysema is simple with the SEM even when dealing with autoptic material obtained 24 to 48 h after death, but the diagnosis of drowning becomes difficult in lungs with chronic emphysema.

Drowning↗

PubMed1990

[A scanning electron microscopic investigation of accessory foramina on the pulpal floor of human primary molars. 1].

The pulp chamber floor of 39 primary first and second molars of 10 mandibuiars of the Indian scull was investigated with a scanning electron microscope for the presence of accessary foramens. All of the teeth investigated were in II A stage of Hellman's dental age. The teeth were sectioned with a diamond disk with a point of 1.5 mm apical to the external furcation area, and 5 mm coronal to the cervical line. The teeth were washed with a supersonic washer and dried. The specimens were mounted with the pulpal floor facing upward on an aluminium stub, plated with gold and observed with scanning electron microscope. As a result of this investigation the following conclusions were obtained. 1) Accessary foramens were observed in 4 mandibulars out of 10 mandibulars and in 14 teeth (35.9%) out of 39 teeth. 2) The maximum 10 and minimum one accessary foramen were found with an averrage of 2.8 per tooth. 3) Accessary foramens were observed with high frequency in the central portion of the pulp chamber floor. 4) The diameter of the opening of the accessary foramens of the mandibular first molars were maximum 83 microns, minimum 8 microns and average 45.4 microns. While maximum 51 microns, minimum 15 microns and average 37.3 microns in mandibular second molars. 5) The opening shape of accessary foramens was classified into three types, round 56.4%, oval 28.2% and others 15.4%. 6) Accessary foramen tend to be present bilaterally in the same individual. 7) It seemed that there is an individual difference in the presence or absence of accessary foramen. One individual has many accessary foramens, while another individual lacks accessary foramen.

Child↗

PubMed1983

Morphology of canine gallbladder. Scanning electron microscope observations on the epithelium.

Examination of the surface topography of canine gallbladder epithelium using the scanning electron microscope reveals subtle changes in the morphology of the cellular components between the full and empty states. In the full state large bays exist between relatively low, ridge-like crests or folds of mucosa which gradually increase in height as the gallbladder empties causing a subsequent reduction in size and volume of the bays. The relaxed gallbladder exhibits an irregular arrangement of tall, closely apposed mucosal folds with intervening deep valleys. The degree of apical convexity of individual epithelial cells will increase as the mucosal folds begin to relax. Other mucosal features most easily observed in the full state were small pit-like intraepithelial glands. The apical surfaces of the epithelial cells exhibit a densely uniform microvillus border and occasional membrane-bounded cytoplasmic protrusions (apical bullae) extending out into the lumen of the organ. The lateral cell membranes and basal lamina were also examined. Correlative methacrylate and transmission electron microscopic findings are included. The functional aspects of these morphological alterations and apical protrusions are discussed.

Animals↗

PubMed2000

Development of a System to Provide Full, Real-time Remote Control of a Scanning Electron Microscope across the Second Generation Internet: The Teaching SEM.

The development and makeup of a real-time full remote control system for the University of Michigan, Department of Materials Science and Engineering Teaching SEM is described. The instrument was initially controlled via the campus local area Ethernet network and cable TV network. The latest implementation employs Fast Ethernet, Asynchronous Transfer Mode (ATM) networks, and moving picture experts group (MPEG) video encoding to effect the remote control via the computer network alone. Remote control demonstrations from Washington, DC, Dearborn, MI, and Emerson School, Ann Arbor, MI are described.

Journal Article↗

PubMed1978

A maturation change detected in the semilunar cartilages with the scanning electron microscope.

The surface of rabbit, cat, monkey and human semilunar cartilages was examined with the scanning electron microscope. A common feature was the occurrence of numerous ridges, undulations and furrows on the surface, but this was thought to be due to marked shrinkage and distortion of cartilage not firmly attached to bone. Humps were seen on the semilunar cartilages of young animals, but pits occurred in adults. This is thought to reflect a maturation change. Humps were seen in a young human semilunar cartilage, but pits were not seen in adult specimens. It is not clear whether pits are truly absent or just masked by the severe ridging produced during the preparation of large human specimens.

Aging↗

PubMed1996

A scanning electron microscope investigation of the effects of pollutants on the hepatopancreatic ceca of Gammarus pulex (L.).

Scanning electron microscope studies were performed on the peripheral muscle network (myoepithelium) of the hepatopancreatic ceca of Gammarus pulex (L.) exposed to lindane, copper, or 3, 4-dichloroaniline (3,4-DCA) for a 24-hr period. The structural integrity of the myoepithelium of gammarids from control and test treatments was assessed using semiquantitative techniques. The lowest observed effect concentrations for structural changes were determined as 29.8 microg liter-1 lindane, 55 microg liter-1 copper, and 8.7 mg liter-1 3,4-DCA. The sensitivity of the bioassay and the significance of the morphological changes observed in the hepatopancreatic ceca of G. pulex are discussed.

Aniline Compounds↗

PubMed1983

[Changes in the cornea following complicated pseudophakia and subsequent keratoplasty (clinical and scanning electron microscope findings)].

An anterior chamber lens (Binkhorst four-loop lens) became dislocated seven weeks after implantation. It was relocated in the right position by means of a small incision. In the course of the following 8 weeks the cornea opacified from the top downward. A penetrating keratoplasty was performed. Intraoperatively it was found that a strand of vitreous had pushed forward between the iris and the lens and was adhering to the back of the cornea. The piece of cornea removed was prepared for the scanning electron microscope. The microscopic findings are described in detail. They correspond exactly to the clinical diagnosis of complete tearing of the endothelium, considerable bullous changes in the parenchyma and degenerative changes in the epithelium. The scanning electron microscope reveals how severe pathologic changes in the cornea can become if a strand of the vitreous becomes adherent to the endothelium.

Cataract↗

PubMed1976

Studies on perithecium of Ceratocystis stenoceras by a scanning electron microscope.

The surface and cavity of the perithecium of Ceratocystic stenoceras were studied with a scanning electron microscope. The body was spherical, 96-231 u in diameter, and the surface was covered with hyphae. The neck was a lanky hollow cylinder and the wall consisted of a bundle of tubular hyphae encircling a central canal. A whorl of hyaline hyphae was found at the tip of the neck. The surface of the neck from the body to a distance of about 1/6 was rough and warty. But the surface of the neck above that place was smooth, on which a regular design could be seen. The wall of the neck the body consisted of 5-6 layers of cells. However, the wall at the tip was of 1-2 layers of cells. The cavity was filled with ascospores. They were like segments of an orange of 1 X 2 u with smooth surface.

Fungi↗