Digital Commons Network^™

Scanning Electron Microscopy Of The Human Thyroid Gland And Its Disorders, Jahn M. Nesland, Manuel Sobrinho-Simoes, Jan Vincents Johannessen

Scanning Microscopy

The characteristic scanning electron microscopic features of the normal thyroid gland, benign thyroid lesions such as nodular (adenomatous) and colloid goitre, adenomas and thyroiditis, and malignant tumors such as papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma are described.

One or more cilia are present in the center of the follicular surface of almost every epithelial cell in the normal thyroid gland as well as in most goitres. Their number is reduced in adenomas and differentiated carcinomas. Medullary carcinomas and anaplastic carcinomas usually lack cilia.

Variation in distribution and appearance of microvilli seems to be related to functional differences …

Signal-To-Noise Ratio Improvement In Electron Beam Testing By Using A Dispersive Analyser, L. Dubbeldam, P. Kruit

Scanning Microscopy

In conventional e-beam testers the potential of a device under test is measured by collecting the secondary electrons (SE's) faster than a certain limit, while the slower SE's are rejected. We have built an e-beam tester in which the slower SE's are also collected. In this paper we will show that this can decrease the minimum measurable voltage substantially. An additional advantage of a double channel analyser is the possible reduction of the influence of fluctuations in the primary beam and in the secondary emission coefficient.

An Electron Beam Tester With Dispersive Secondary Electron Energy Analyser, P. Kruit, L. Dubbeldam

Scanning Microscopy

The design principles of a new, experimental e-beam tester are described. Using the magnetic field of an immersion objective lens the secondary electrons are guided to an energy analyser between the condenser lenses and the objective lens. The latter can now have a short working distance and small aberrations. The electron energies are analysed by a combination trochoidal motion - retarding field analyser, which enables detection of the faster secondary electrons on one detector and detection of the slower secondary electrons on a second detector. The benefit of this set up is a possibility for voltage contrast isolation, normalization with …

Storage Of Sperm In The Reptilian Oviduct, Daniel H. Gist, Jeffrey M. Jones

Scanning Microscopy

Female reptiles have the ability to store sperm within their reproductive tracts for extended periods of time. Sites of sperm storage in lizards and snakes include both the anterior vagina and the infundibulum. Vaginal receptacles are found in between longitudinal folds (snakes) and in tubules formed by invaginations of the epithelium (lizards). Infundibular receptacles are alveolar or tubular in structure and are formed from invaginations into the lamina propria of the oviduct wall. In turtles, sperm are stored in the posterior portion of the tuba, in tubular albumen-secreting glands. Sperm may be embedded within the cells of the receptacles, but …

Scanning Electron Microscopy Of Burnt Electric Wires, R. P. Singh

Scanning Microscopy

Aluminium and copper wires were burnt by electric short circuit and by outside flame. These wires have been studied under scanning electron microscope with a view to distinguish them in fire cases. It was observed that there were extensive grains on the cylindrical surfaces near the ends of copper wires burnt by electric short circuit. The grainy structures were continuously decreasing with distance from the ends and vanished. Aluminium wires had bucklings starting from the ends and decreasing on subsequent portions. These features were found to have a potential advantage to identify the ends specially those which did not have …

Ureteroscopic And Scanning Electron Microscopical Findings In Ureteral Anastomoses After Segment Resection, Johannes B. Pohl, Ulrike B. Meyer-Jürgens, Dietrich B. Leusmann

Scanning Microscopy

In an experimental study on 8 canine ureters, end-to-end anastomoses were performed after segmental resection between 9 and 13 cm, using two different surgical techniques. After 3 months of observation the three-dimensional structure of the anastomosis and the surrounding areas was investigated by ureteroscopy and scanning electron microscopy. 3 types could be differentiated by the morphologic features of the ureteral lumen: normal width, segmental stricture, and circumferential stricture. The results offer a plausible explanation for the occasional discrepancy between histologic findings of relatively normal lumen width, and functional disorders apparently reflecting ureteral stenosis. They further support that excellent functional and …

The Role Of The Cytoskeleton In Endothelial Repair, Avrum I. Gotlieb, Michael K. K. Wong, Patricia Boden, Alan Choo Fone

Scanning Microscopy

The injured endothelium undergoes rapid repair of areas of cell desquamation in order to maintain the structural integrity of the endothelial surface. Endothelial repair involves a series of processes which include endothelial cell spreading, translocation, and proliferation. These processes are well defined events which occur sequentially in time. Spreading and translocation are mediated by the cell cytoskeleton - F-actin microfilaments and microtubules and associated centrosomes. The regulation of these processes is complex and is likely due to soluble factors present at the site of injury which are released from activated endothelial cells, platelets, the subendothelial substratum, activated serum factors, and …

The Vascularization Of The Vertebral Column Of Rats, M. A. Konerding, M. Blank

Scanning Microscopy

The intrinsic and extrinsic blood supplies of the vertebral column of rats have been examined by corrosion cast with Mercox CL2B(R). The close functional and topographic relationship of vessels to supplied structures were exposed by fractionated maceration of the soft tissues. The segmental arteries diverge into an anterior, median and posterior group with various anastomoses between their branches. Vertebral bodies and intervertebral discs are preferably supplied by branches of the anterior and median section. The vessels reaching the vertebral body from the dorsal side diverge in a treelike branching mode into the direction of the vertebral endplate. The venous drainage …

Industrial Problem Solving With Microbeam Analysis, Klara Kiss

Scanning Microscopy

The objective of this paper is to provide an overview of the microbeam analytical techniques and to help select the appropriate one to solve complex problems often arising in today's high - tech industries. case histories are given to show how renowned analytical service laboratories and microbeam experts formulated their strategies to approach a real life problem, what type of conclusions were deduced from the data and, finally, how the problem was solved.

Tooth Enamel Structure In The Koala, Phascolarctos Cinereus: - Some Functional Interpretations, William G. Young, Maria Mcgowan, Terrence J. Daley

Scanning Microscopy

The purpose of this study is to determine whether the structural organization of Pattern 2 marsupial enamel in the Koala is disposed to resist wear on the sectorial crests of the molar teeth. The orientation of wear on the crests is uniformly delineated by parallel scratches on their polished surfaces. Twin blades, a leading and a trailing edge of enamel are formed on each crest by wear into dentine on which the differential wear at enamel to dentine interfaces indicates that the direction of wear is labial to lingual.

96 leading and trailing edges from 12 koala molars were examined …

Somites And Axon Guidance, Kathryn W. Tosney

Scanning Microscopy

The somites are arrayed in a repeating pattern along the longitudinal axis of the embryo, as are the developing sensory and sympathetic ganglia and the spinal nerves. This pattern is not a coincidence: the somite imposes a segmental pattern on the cells and axons that invade it. Both neural crest cells and axons prefer the anterior portion of the sclerotome (the ventral part of the somite) for outgrowth. What differences in anterior and posterior sclerotome are responsible? I used scanning electron microscopy to ask whether these populations differed on the tissue level in chick embryos. This study shows that differences …

Numerical Approaches To Non-Destructive Depth Profiling By Variable Angle X-Ray Photoelectron Spectroscopy, P. C. Mccaslin, V. Young

Scanning Microscopy

Variable angle x-ray photoelectron spectroscopy (VAXPS), also known as angle-resolved x-ray photoelectron spectroscopy (ARXPS), is a method which can be used to depth profile the near surface region non-destructively. The intensity variation with angle of a given energy level in a sample contains the complete information about the concentration profile of the photoionized component in the depth probed. It has been shown that the intensity is the Laplace transform of the concentration profile. Theoretically it should be possible to uniquely determine the concentration profile as the inverse Laplace transform of the intensity data. After a brief background sketch, the numerical …

Interactions Between A Condensed Target And A Non-Equilibrium Plasma: Acid-Base Reactions At The Interface, J. Amouroux, J. L. Brisset, A. Doubla, A. Gicquel, A. Goldman, F. Rouzbehi

Scanning Microscopy

A new approach of plasma processes of industrial use is presented, with emphasis on the chemical properties of the plasma gas. Reactions occurring at the gas/target interface are for the first time interpreted in terms of acid-base reactions and pertinent examples are given of laboratory experiments and of industrial treatments (e. g., etching, plasma polymerization or surface modification processes). Proton exchanges between the plasma phase and an aqueous target gives evidence of Bronsted acid-base phenomena. Illustrations of Lewis acid-base characters are provided by the role of biradicals (e.g., halogenocarbenes, nitrenc) which are the main reacting species in etching or in …

Evolutionary Aspects Of Reptilian And Mammalian Enamel Structure, A. Sahni

Scanning Microscopy

The evolution of enamel structure is dealt with here on the basis of fossil reptiles and mammals ranging from the Triassic to the present. The evidence suggests that prismatic enamel had developed in some therapsid reptiles and the mammal, Eozostrodon about 180 million years ago. For the next 100 million years, mammalian evolutionary history is sparingly documented and this is reflected in the poor record of enamel evolution during this period. The few Jurassic reptiles and mammals studied suggest a pre-prismatic structure. In the Late Cretaceous (BO to 65 million years ago) when the fossil record improves, mammalian enamel investigated …

The Use Of Silver Nitrate Staining And Backscattered Electron Imaging To Visualize Nematode Sensory Structures, D. J. Vanderburgh, C. A. Ackerley, D. H. Lynn, R. C. Anderson

Scanning Microscopy

Parasitic nematodes of the species Cosmocercoides variabilis were stained with silver nitrate and examined with backscattered electron imaging (BEI). Sensory papillae were selectively highlighted in backscatter images. Silver stain deposited on papillae was located on the papillary surface as well as on the underlying dendritic process. Portions of the body cuticle were also stained. Some cuticular staining was attributed to non-specific deposition of silver but, consistent patterns of cuticular staining were noted in the anterior and posterior regions. This observation suggests that some staining of the cuticle was specific. Results of this preliminary work suggest that BEI is a technique …

Megakaryocyte Motility And Platelet Formation, Robert M. Leven

Scanning Microscopy

The mechanism of platelet formation is reviewed with special emphasis on the role of the cytoskeleton. The three major theories for platelet formation are by cytoplasmic budding, cytoplasmic dissolution or pseudopod formation. Most evidence indicates that platelets form as fragments of megakaryocyte pseudopodia. Pseudopodia formation is stimulated in vitro by thrombocytopenic rabbit plasma. It is inhibited by vincristine and altered by taxol. Cytochalasins cause pseudopodia to form in isolated megakaryocytes. Therefore, normal pseudopodia formation may depend on a combination of microfilament disorganization and microtubule elongation.

Optical Emission And Laser Spectroscopy In Studies Of Sputtering: Actual Research Activities And Recent Achievements, W. Husinsky, G. Betz

Scanning Microscopy

Laser Spectroscopy has been developed into a powerful tool for the detection and energy analysis of neutral particles. Laser Induced Fluorescence Spectroscopy (LIF) has yielded a wealth of information about sputtered neutral particles. In addition, Laser Ionization Spectroscopy has recently offered an increased detection sensitivity. In this paper a summary of recent results is given. By combining LIF with other methods capable of measuring densities and energy distributions of sputtered excited atoms in short lived states, new information about sputtering and excitation mechanisms have been recently obtained and will be summarized here.

Scanning Electron Microscopy Application In Clinical Research, R. Laschi, G. Pasquinelli, P. Versura

Scanning Microscopy

Our personal experience on the application of scanning electron microscopy in cardiology, gastroenterology and ophthalmology is reviewed.

SEM has not yet significantly contributed to myocardium pathology. However, in the near future, SEM could be a reliable technique to complete the information available from other sources. As to atherosclerosis, SEM allowed us to improve our knowledge of the early stages of the disease; some pathological features, not always detected by conventional morphological examinations, can be documented. An important contribution to gastrointestinal pathology was made by SEM investigations both in the staging of some important diseases (i.e., coeliac disease, peptic ulcer, Crohn's …

Proton Energy Loss Spectroscopy For Surface Monolayer Analysis, Noriaki Matsunami

Scanning Microscopy

A survey is given of recent advances in the use of high-energy proton backscattering spectroscopy or proton energy loss spectroscopy (PELS) under the glancing incidence geometry for monolayer-sensitive analysis. Two theories of the energy loss involved in the PELS are described, based on the continuous and impact parameter dependent slowing down models. The latter theory leads to the azimuthal angle dependence of the energy loss. It is also shown that this technique is applicable to underlayer composition analysis

The Normal Structure Of Regional Feline Gastric Mucosae: Scanning Electron Microscopic Study, M. Al-Tikriti, F. Al-Bagdadi, R. W. Henry, J. Hoskins, C. Titkemeyer, G. Strain

Scanning Microscopy

Regions of cat's stomach can be identified by looking at the surface epithelial cells by scanning electron microscopy (SEM). The luminal surface of cells of the cardiac region were elongated, of the fundus rounded, of the corpus polygonal shaped, and of the pyloric region diamond shaped. The quantity and distribution of microvilli covering the epithelial cells varies, being abundant and evenly distributed in the cardiac region and gradually decreasing in number toward the gastro-duodenal junction, where they were confined to cell perimeters. The colliculi varied in shape and distribution from few in the fundus and corpus to numerous in the …

Analysis Of Thick Targets By Proton-Induced X-Ray Emission, J. L. Campbell, A. Perujo, W. J. Teesdale, J. A. Maxwell

Scanning Microscopy

Most published PIXE (proton-induced X-ray emission) work concerns thin targets. Recently progress in improving both the fundamental data base and in developing a range of standardization techniques has propelled thick target analysis to the forefront of activity in the PIXE field. Limits of detection are a complex issue depending not only on the continuous background but also on the characteristic X-rays of the matrix; in favorable cases a few ppm may be reached in convenient analysis times. The unfolding of multi-element PIXE spectra is akin to the same problem in EPMA (electron probe microanalysis), and EPMA methodologies, especially as regards …

Microvascular Corrosion Casting Of The Lung. A State-Of-The-Art Review, Dean E. Schraufnagel

Scanning Microscopy

Corrosion casting and viewing of replicas with the scanning electron microscope is an excellent way to study the microvascular structure of the lung. This method can demonstrate aspects of the three-dimensional relationships, branching patterns, maximum diameters, arterio-venous connections, unusual sized and shaped capillaries, development and growth, neovascular structures and changes in development and disease better than any other means. Comparisons can be made in many experimental conditions and fundamental information obtained to answer physiologic questions. This paper reviews how the lung microvasculature has been studied by corrosion casting and scanning electron microscopy and indicates new areas where investigation might be …

Exposure Of Vascular Smooth Muscle Cells For Analysis With The Scanning Electron Microscope, Bryan G. Miller, Andrew P. Evan, H. Glenn Bohlen

Scanning Microscopy

There has been interest in using the scanning electron microscope (SEM) to study the structure of tissues obscured by other cellular or non-cellular elements almost since the SEM was first used to examine biological tissues. Such interest includes the vessel wall and, in particular, the vascular smooth muscle cells. This paper presents a review of the three basic methodologies that have been employed to allow examination of the vascular smooth muscle, 1) blunt dissection, 2) digestion and 3) microdissection. Discussion of other perivascular elements was not a focus of this review. Also presented is the application of these different methodologies …

Scanning Electron Microscopy Of Black Stain On Human Permanent Teeth, J. Theilade, K. M. Pang

Scanning Microscopy

Black stain may develop on the coronal surfaces of human teeth, and this type of stain is common in the Hong Kong Chinese population. The present study was undertaken to ascertain if the deposit conforms in composition to the black stain found elsewhere, and to describe its ultrastructure using the scanning electron microscope. Gram-stained smears were made from black stain on the teeth of 11 adult Hong Kong Chinese and studied microscopically. From another 15 persons extracted teeth exhibiting black stain were obtained and fixed. Two ground sections were made from each tooth, one was stained with toluidine blue, the …

Ultrastructural Analysis Of Enamel Formation During In Vitro Development Using Chemically-Defined Medium, P. Bringas Jr., M. Nakamura, E. Nakamura, J. Evans, H. C. Slavkin

Scanning Microscopy

To test the hypothesis that enamel biomineralization is regulated by sequential expression of an intrinsic genetic program, we designed experiments to determine if a serumless, chemically-defined medium is permissive for position-dependent ameloblast differentiation and subsequent enamel tissue-specific biomineralization in vitro. In the absence of serum or other exogenous growth factors, Swiss Webster strain mouse embryonic (15-and 16-days gestation) mandibular first molar tooth organs (cap stage) developed within 21 days in vitro into well-defined molar tooth organs expressing dentine and enamel biomineralization. Analysis of data obtained from von Kossa histochemistry for calcium salt formation, as well as ultrastructural information obtained …

Secretory Ameloblasts And Calcium Distribution During Normal And Experimentally Altered Mineralization, S. H. Ashrafi, Dale R. Eisenmann, A. E. Zaki

Scanning Microscopy

The distribution of calcium in relation to secretory ameloblasts of the rat incisor was studied. An experimental model system in which enamel mineralization was temporarily inhibited by injecting sodium fluoride and cobalt chloride was used. Potassium pyroantimonate (PPA) cytochemistry, electron energy loss spectroscopy (EELS), and energy dispersive X-ray spectrometry (EDS) were used to clarify the role of the ameloblast in controlling calcium distribution during normal and experimentally altered enamel mineralization.

Secretory ameloblasts chemically-preserved in glutaraldehyde either with or without PPA were analyzed for calcium; those preserved with PPA showed higher concentrations of calcium than did those preserved with glutaraldehyde only. …

Fictitious Calculi And Human Calculi With Foreign Nuclei, P.-T. Cheng, K. P. H. Pritzker, J. Richards, D. Holmyard

Scanning Microscopy

The correlative approach employing polarized light microscopy, x-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction and energy dispersive x-ray microanalysis proves to be very useful in identifying fictitious calculi and genuine human calculi with foreign body nuclei. The common artifacts as reported in the literature and observed also by us were minerals, vegetable and plant seeds, cereals, sand grains and sea shell fragments.

Two interesting cases involving foreign body nuclei have been reported: one urinary calculus containing a piece of plastic-coated titanium foil in the center; one nasal calculus with a nut as a nucleus. …

Effects Of Fractionated Irradiation On The Esophageal Mucosa: A Scanning And Transmission Electron Microscopic Study, M. Albertsson, C-H Hakansson, C. Mercke, H. Morner

Scanning Microscopy

The mucosa of rabbit esophagus was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy investigations. Examination was made 1-10 days after each fractionation schedule. Light microscopy showed dose-dependent edema of the irradiated mucosa which also could be seen and scored from SEM pictures. SEM investigations showed that this was accompanied by loosening of microridges and a slightly increased cell loss. By SEM, a varying amount of bacteria could be seen which did not make intimate contact with the surface cells.

During …

Effects Of Cis-Dichlorodiammineplatinum Alone And In Combination With Ionizing Radiation On The Esophageal Mucosa: A Scanning And Transmission Electron Microscopic Study, M. Albertsson, C-H Hakansson, C. Mercke

Scanning Microscopy

Cis-dichlorodiammineplatinum (cis-DDP) has for more than 20 years been part of the therapeutic arsenal of oncology. Most of the knowledge about its biological action is based on clinical investigations and therefore an examination of the influence of cis-DDP at the cellular and sub-cellular level is necessary. Five mg of cis-DDP was given intraperitoneally (i.p.) to ten rabbits. Ultrastructural examinations were performed on the upper and lower parts of the esophagus each day after the injection on the following ten days. Another 50 rabbits were given 5 mg cis-DDP and were irradiated in an area just beneath the hypopharynx. They were …

Channel Plate Detection In Low Energy Scanning Electron Microscopy, H. F. Helbig, R. D. Rydgren, L. Kotorman

Scanning Microscopy

Microchannel plate (MCP) electron detectors compare favorably with the Everhart-Thornley detector for producing SEM images from both secondary and back-scattered electrons. The MCP is a compact array of 10⁵ - 10⁶ channel electron multipliers with a gain in excess of 10⁶ and the collective ability to count ~ 10⁸ electrons per second. The MCP can be mounted coaxially with the beam allowing un-tilted sample orientation and electron collection into a large, field-free solid angle. The speed and low noise of the MCP allow images to be made in less than one second at moderate beam currents …