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PubMed1979

Scanning electron microscopic studies of the zonular apparatus in human and monkey eyes.

Scanning electron microscopic studies of the zonular apparatus in 10 human and 17 monkey eyes revealed two functionally different sets of zonular fibers: the "main fiber" and the "tension fiber" system. The two systems are connected, forming a broad, sagittally oriented "zonular plexus" within the pars plicata of the ciliary body. The zonular plexus is attached to the ciliary epithelium by the tension fibers, which leave the main system and run obliquely forward to the epithelium deep in the valleys of the ciliary processes. Anteriorly, the zonular plexus splits into the two branches of the "zonular fork," which run respectively to the anterior and posterior aspect of the lens. Thus the zonular plexus can act as a fulcrum. The three-dimensional architecture of the zonular apparatus is consistent with a new concept of accommodation.

Accommodation, Ocular↗
PubMed2004

Scanning electron microscopic study of third-instar warbles in yak in China.

Scanning electron microscopic observations were performed to compare the structures of third-instar of three species of warbles (Hypoderma bovis, H. lineatum and H. sinense) that infest yak in China. The heads of the warbles consisted of mouths and opercular sutures with spinal bands between them. We could not detect any morphological differences in the shape of the warble's heads among these three species. The spiracular plate of H. bovis was strongly concaved and had numerous spines at the spiracular opening rims. The H. lineatum had flat spiracular plates and no spines on the spiracular plates. In the case of H. sinense the spiracular plate was as flat as that of H. lineatum but had small sized and fewer spines on the spiracular plates. At the ventral side on the tenth segment of the warble body of H. bovis the spinal band was absent. Although H. lineatum had only one band at the posterior border on the tenth ventral segment, H. sinense had two bands of spines at the anterior and posterior border on the tenth segment.

Animals↗
PubMed1977

Bone remodeling in pathologic conditions. A scanning electron microscopic study.

Bone remodeling in pathologic conditions was studied with the scanning electron microscope (SEM). Benign and malignant ossification were examined in cases of myositis ossificans, ossifying fibroma, osteoid osteoma, and osteosarcoma, Resorption of bone due to invasion by non-ossifying tumors was found in cases of squamous cell carcinoma, adenocarcinoma, ameloblastoma, and multiple myeloma. Bone formation due to excessive production of growth hormone was studied in a case of acromegaly. Resorption of bone due to pathologic processes resembled the pattern found in surfaces which were undergoing resorption by osteoclasts. Lamelar-cortical bone formation in acromegally was similar in nature to normal bone. The deformities were rleated to the excessive continuous osteogenesis that occurs in these instances. Neoplastic ossification was characterized by calcifying globules, the diameters of which ranged from 1 to 3 micron. The surfaces of these globules were constructed of minute calcospherites with diameters ranging from 0.1 to 0.3 micron. It is suggested that the pattern of globular calcification is similar to the type that was found with the SEM in fetal bone and cartilage, during healing of fractured bone, and also with the TEM in normal and pathologic calcification.

Acromegaly↗
PubMed1981

Onychomycosis (trichophyton mentagrophytes). A scanning electron microscopic observation.

Nails from four patients, infected with dermatophytes, were investigated with the scanning electron microscope (SEM) to gain insight into the spatial arrangements of the dermatophytes within the nail. Fungal hyphae could be detected in nails of all four patients. A toenail from one patient infected with Trichophyton mentagrophytes was more extensively studied and the results are presented in this paper. Light microscopic observations with bright field illumination and Nomarski interference contrast confirmed the dermatophytic infection. Fungal hyphae found with the SEM distally on the ventral part of the toenail showed typical T. mentagrophytes structures and the comparison with cultured material clearly demonstrated the correspondence in morphology and size. Besides the fine structural morphology of the invasion of fungal hyphae into the nail plate between the horny cells and/or directly into corneocytes, "tunnel"-like holes were observed in paraffin embedded sections after removal of the paraffin. Scanning electron microscopy, with its enormous focal depth, yielded far more information than light microscopic techniques about the three dimensional behavior of dermatophytes in the nail.

Foot Dermatoses↗
PubMedDate not supplied

Charging compensation of alumina samples by using an oxygen microinjector in the environmental scanning electron microscope.

A gas microinjector system was set up in an environmental scanning electron microscope (ESEM) to create an oxygen atmosphere around the alumina samples for the charging compensation under a pressure between 2 x 10(-5) Pa approximately 2 x 10(-2) Pa. At low pressures, the skirt effect of the electron scattering can be degraded, which results in improvement of the imaging contrast and increase of the signal/noise ratio. The sample current (I(SC)) and the Duane-Hunt limit were measured to evaluate the charging effect.

Journal Article↗
PubMed2006

Quantitative secondary electron energy filtering in a scanning electron microscope and its applications.

Two-dimensional dopant mapping in the scanning electron microscope (SEM) has recently attracted attention due to its ability to measure dopant levels rapidly with high spatial resolution while requiring little or no sample preparation. The dopant concentration could be derived from the energy distribution of secondary electrons emitted per doped region. However, the lack of reliable quantification, when standard SEM imaging is used, has so far hindered a wide application of the technique. This paper aims to resolve this problem with quantitative energy-filtering using a through-the-lens (TTL) detector in a field emission gun SEM (FEG-SEM). We have used the linear shift obtained in the SE energy distribution with variable specimen bias using sample containing copper wires, defined as the experimental detector response R(exp), to quantify the energy filtering. Using different experimental conditions, values of (2.42+/-0.04)<or=R(exp)<or=(3.01+/-0.05) were obtained. Results were validated by comparison with calculations obtained from ray-tracing simulations. Recommendations for the linear range of the TTL detector as an energy filter were established on the basis of these results. In addition, using our quantitative energy-filtering capabilities, the potential difference across a Si pn-junction was measured to be 0.81+/-0.10 V, which is in good agreement with the calculated value.

Journal Article↗
PubMed1998

A simple method for the acquisition of high-quality digital images from analog scanning electron microscopes.

A method is described for converting video signals of analog scanning electron microscopes (SEMs) into digital images of high quality. A plug-in card commercially available for personal computers is used for the on-line analog/digital conversion. A Windows application program written by the authors, together with low-level software drivers supplied with the plug-in card, allow digital images to be recorded, to be displayed simultaneously on the computer monitor and to be saved as a file in a standardized format. Compared to conventional photographic images obtained from the SEM camera system, the digital images possess superior sharpness of outline, excellent image definition, diminished noise and well-defined grey-scale tones. This method provides SEM images of high quality for less than $1000 from most older analog SEMs. In addition, the advantages of digital image processing can be applied to analog SEMs, including contrast enhancement, digital filtering and multichannel recording.

Journal Article↗
PubMed1989

Scanning electron microscopic observation on the surface ultrastructure of leucocytes in CSF.

Using scanning electron microscope (SEM), The CSF leucocytes from 3 healthy subjects and 12 patients with various NS diseases were observed. The findings were used to compare with those by optical microscope (OM) and those of human peripheral blood cells by SEM. Five types of CSF cells with particular surface structures, are emphasized in relation to both optical microscopic findings and the involved diseases.

Cell Membrane↗
PubMed1975

Scanning electron microscopic studies on the formation of cardiac intercellular connection in culture.

The fine surface structural appearance of the cardiac intercellular connection was studied scanning electron microscopically in culture. When individual heart cells contract each other, they start to beat synchronically. On the base of scanning electron microscopic observation, the early pattern of the formation of it could be suggested as follows: five ramified processes extend from the edge of the cells, and the ends of these processes bridge each other to form the intercellular connection.

Animals↗
PubMed2003

Research of the entry of rare earth elements Eu3+ and La3+ into plant cell.

Whether rare earth elements can enter into plant cells remains controversial. This article discusses the ultracellular structural localization of lanthanum (La(3+)) and europium (Eu(3+)) in the intact plant cells fed by rare earth elements Eu(3+) and La(3+). Eu-TTA fluorescence analysis of the plasmalemma, cytoplast, and mitochondria showed that Eu(3+) fluorescence intensities in such structures significantly increased. Eu(3+) can directly enter or be carried by the artificial ion carrier A23187 into plant cells through the calcium ion (Ca(2+)) channel and then partially resume the synthesis of amaranthin in the Amaranthus caudatus growing in the dark. Locations of rare earth elements La(3+) and Eu(3+) in all kinds of components of cytoplasmatic organelles were determined with transmission electron microscope, scanning electron microscope, and energy-dispersive X-ray microanalysis. The results of energy-dispersive X-ray microanalysis indicated that Eu(3+) and La(3+) can be absorbed into plant cells and bind to the membranes of protoplasm, chloroplast, mitochondrion, cytoplast, and karyon. These results provide experimental evidence that rare earth elements can be absorbed into plant cells, which would be the basis for interpreting physiological and biochemical effects of rare earth elements on plant cells.

Cations↗
PubMedDate not supplied

Use of backscattered electron detector arrays for forming backscattered electron images in the scanning electron microscope.

The backscattered electron (BSE) signal in the scanning electron microscope (SEM) can be used in two different ways. The first is to give a BSE image from an area that is defined by the scanning of the electron beam (EB) over the surface of the specimen. The second is to use an array of small BSE detectors to give an electron backscattering pattern (EBSP) with crystallographic information from a single point. It is also possible to utilize the EBSP detector and computer-control system to give an image from an area on the specimen--for example, to show the orientations of the grains in a polycrystalline sample ("grain orientation imaging"). Some further possibilities based on some other ways for analyzing the output from an EBSP detector array, are described.

Journal Article↗
PubMed1985

Scanning electron microscope study of Pseudomonas putida colonies.

Pseudomonas putida colonies were examined by scanning electron microscope. A variety of cell morphologies, multicellular arrangements, and extracellular materials were observed in the fixed material. Different regions of a single colony showed characteristic organizations of these architectural elements. In some cases, the detailed microstructure of the fixed colony surfaces observed by scanning electron microscopy could be correlated with macroscopic patterns visualized by histochemical staining and surface relief photography of live colonies. Extracellular materials were seen to extend onto the agar surface beyond the boundaries of the cell mass, and the final structures of these materials, after fixation and desiccation, were colony specific. The significance of these features of colony microstructure for formulating hypotheses about the control of colony morphogenesis is discussed.

Microscopy, Electron, Scanning↗
PubMed1978

A scanning electron microscopic study of normal human oxyntic mucosa using blunt dissection and freeze fracture.

Biopsies from the fundic mucosa of healthy volunteers were examined by scanning electron microscopy following blunt dissection and freeze fracture. The mucosal surface exhibited a cobblestone appearance. With increased magnification, microvilli could be demonstrated on the luminal surface of individual surface cells. Blunt dissection of the gastric mucosa revealed tubular gastric pits descending from the surface until they opened into branched tubular gastric glands. The gastric glands are irregular in outline due to the knoblike projections of individual parietal cells. The internal structure of the component cells also was examined with the scanning electron microscope following freeze fracture. Mucous granules were observed in the apical portion of surface epithelial cells. Lumina of parietal cell canaliculi were found to be continuous with the lumen of the gastric glands. Pepsinogen granules could be seen throughout the cytoplasm of chief cells. The blunt dissection-freeze fracture technique utilizing the scanning electron microscope allows, for the first time, a three-dimensional view of human gastric mucosa, including the gastric pits and glands as well as some of the internal architecture of component cells.

Adult↗
PubMed1991

Scanning electron microscopic study of capillary change in bleomycin-induced pulmonary fibrosis.

The architectural changes which occur in the capillaries are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was occasionally undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in twenty rats by an intratracheal injection of bleomycin. After 30 days the rats were sacrificed, and light microscopy and scanning electron microscopy were performed. The vascular trees of both lungs were cast with methacrylate. Light microscopically, the pulmonary fibrosis was patchy and inflammatory cell infiltration was rather sparse. Scanning electron microscopically, the intercapillary spaces became wider; and some capillaries revealed large irregular dilatation. The pleural and alveolar capillaries were variably dilated. The pleural capillary diameter was increased (P = 0.06), and the capillary plexus diameter was decreased (P = 0.00). Distance between the capillary branches of the pleural surface was increased (P = 0.06). The appearance of irregularly shaped capillaries, an increase in diameter with variable dilatation of alveolar capillary rings and a decrease in branching between the capillaries, resulting in a loss of surface area are the main scanning electron microscopic findings of the remodeling which occurs pulmonary capillaries in bleomycin-induced pulmonary fibrosis.

Animals↗
PubMed1986

[Changes in the myocardial mitochondria in the dynamics of ventricular fibrillation (based on scanning electron microscopic data)].

Left ventricle of the rabbit heart was studied in the scanning electron microscope 1,2 and 5 minutes after the heart fibrillation induced by an impulse electrical current. It is found that as long as the fibrillation developed the degree of the structural heterogeneity of the heart muscle increased, the swelling of mitochondria and rough damage of their membranes occurred.

Animals↗
PubMed1980

Secretory phenomenon of the adenohypophyseal cells viewed with the scanning electron microscope.

Exocytosis from rat adenohypophyseal cells, probably somatotrophic, was studied in the scanning electron microscope after freeze fracturation of the glands. This technique permitted the distinguishing of a clearly delimited exoplasm interrupted by the passage of the secretory granules. It was postulated that the exoplasm could be involved in the control of the release of secretory granules in the endocrine cells studied. At the basal cell surface a simultaneous discharge of several secretory granules has been detected.

Animals↗
PubMed1984

Macrophages isolated from periapical granuloma: a scanning electron microscopic study.

Macrophages isolated from human periapical granulomas were observed under the scanning electron microscope to analyze the surface architecture of the cell membrane. There were marked variations in form, degree of cell spreading, and surface morphology among macrophages of the same specimen. In addition, active phagocytosis of foreign particles or erythrocytes and close contact with other cells were observed. Our findings suggest that these events may represent different states of macrophage activation and provide the basis for further studies on the role of macrophages in host defense mechanisms.

Cell Membrane↗