Digital Commons Network^™

Scanning Electron Microscopy Of Vertebrate Cerebellar Cortex, Orlando J. Castejón

Scanning Microscopy

In this study, the Golgi method for light microscopy, transmission and conventional scanning electron microscopy, the ethanol-cryofracturing technique, the freeze-fracture method for SEM, and the freeze-etching method have been used in conjunction to analyze the three-dimensional cytoarchitectonic arrangement and intracortical circuits of vertebrate cerebellar cortex. Approximately more than 100 specimens of mice, rat, teleost fishes and human cerebelli were processed by the above mentioned techniques. A chronological review of other methods for studying hidden surfaces of cerebellar nerve cell has been also described. The three-dimensional morphology, outer and inner surfaces of granule, Golgi, Purkinje and stellate cells were reviewed by …

Surface Roughening Studies By Field Emission, R. Gomer, Y. M. Gong

Scanning Microscopy

Measurements of surface self-diffusion by the field emission fluctuation method along the zones (011)-(112) and (011)-(001) of a tungsten emitter show both 2 and I dimensional diffusion, attributed to diffusion of W atoms on the terraces and of kinks along the edges of the stepped surfaces found in these zones. At 950 K -1000 K the steps along (011)-(112) disorder completely, as indicated by the merging of the two types of diffusion into a single, 2-dimensional regime. Along (011)-(001) definite transitions can only be seen on (023) and (017). The transition temperatures are much lower, ~750 K.

An Electron Microscopic Study Of Microfibrils Of Bone Marrow, Ferrell R. Campbell

Scanning Microscopy

After fixation of bone marrow with glutaraldehyde, tannic acid and saponin, a delicate network of microfibrils (10 nm) was observed in the extracellular space. Masses of microfibrils were most frequently observed between the endothelial cells of the sinusoidal wall and adventitial reticular cells, but were also observed at other sites throughout the marrow stroma. Microfibrils are an important component of the extracellular material of bone marrow and appear to provide an anchoring substrate for the endothelium.

An Algorithm For On-Line Digital Image Processing For Assisting Automatic Focusing And Astigmatism Correction In Electron Microscopy, Norio Baba, Eisaku Oho, Koichi Kanaya

Scanning Microscopy

An algorithm for processing a diffractogram of an electron image input by an on-line system has been improved, with the aid of projection theory, so as to achieve real time operation. This algorithm can, therefore, automatically focus in scanning electron microscope, and correct for the astigmatic aberration of both transmission and scanning electron microscopes by analyzing the spectrum computed from the diffractogram. Experimental results show that this algorithm is effective for detecting the amount of defocus and astigmatism in both transmission and scanning electron microscopes.

Characteristics Of An Electric/Magnetic Quadrupole Detector For Low Voltage Scanning Electron Microscopy, M. Brunner, R. Schmid

Scanning Microscopy

The electric/magnetic quadrupole detector allow's efficient detection of secondary electrons in low voltage scanning electron microscopy without introducing disturbing aberrations. The original detector of this type was built in 1986; it has now been equipped with scintillator-photomultiplier assemblies on both positive electrodes. Their signals, A and B, can be combined to A+B or A-B, thus enhancing or suppressing different types of contrast. The aberration disc produced by the present design of detector was estimated to have a diameter of 10 nm. Experimentally, no deterioration of image resolution was observed. The collection efficiency was predicted to be 26% and can be …

Quasi-Elastic Scattering Studies Of Water Diffusion, H. E. Rorschach, D. W. Bearden, C. F. Hazlewood, D. B. Heidorn, R. M. Nicklow

Scanning Microscopy

Quasi-elastic neutron scattering is a powerful method to study the dynamics of protons in biological systems. The technique has been used both for the study of water diffusion and protein motion. The neutron scattering measurements on water show that the translational and rotational diffusion coefficients in biological systems are reduced from bulk values. We review the measurements on water in frog muscle, cysts of artemia, and phycocyanin. Measurements on dry trypsin and trypsin-D₂O solutions over the temperature range 75-300K show that there is proton motion at the one angstrom level even in the dry or frozen state.

Secondary Electron Emission Induced By Electron Bombardment Of Polycrystalline Metallic Targets, R. Bindi, H. Lanteri, P. Rostaing

Scanning Microscopy

The aim of the present paper is the analysis of the backward secondary electron emission phenomenon, under electron bombardment, on the basis of experimental and theoretical results. Among the theoretical models, we will mention the phenomenological models, those which use a Monte-Carlo type simulation method, and those based on the numerically solved Boltzmann transport equation.

To correlate experimental and theoretical results on all the data characterizing this phenomenon, it is necessary to use an appropriate description for the excitation process of the internal secondary electrons; it also needs a complete description of the transport process for the excited electrons, which …

Ultrastructure Of Spermatozoa From Domesticated Birds: Comparative Study Of Turkey, Chicken And Guinea Fowl, R. J. Thurston, R. A. Hess

Scanning Microscopy

Typical for non-passerine birds, the spermatozoa of the turkey, chicken and guinea fowl were vermiform with a maximum width of 0.5-0. 7μm and lengths of 90μm for chicken sperm, and 75-80μm for those of the turkey and guinea. An acrosome, nucleus, midpiece and flagellum could be distinguished by SEM.

The acrosomal cap projected over a perforatorium surrounded by granular material. At its base, the cap encircled apical projections of the nucleus. The nucleus consisted of dense chromatin, and formed a concave implantation fossa where it joined the midpiece of the tail. For turkey and chicken spermatozoa, the neck region of …

Utah Science Vol. 48 No. 2, Summer 1987

Utah Science

66 SO WHAT? C. Elmer Clark

69 BIOLOGY DEPARTMENT

74 SOIL SCIENCE & BIOMETEOROLOGY DEPARTMENT

81 THE UTAH AGRICULTURAL EXPERIMENT STATION: SCIENCE SERVING AGRICULTURE A review of Experiment Station research facilities and services.

97 FAMILY & HUMAN DEVELOPMENT DEPARTMENT

99 ECONOMICS DEPARTMENT

104 AGRICULTURAL & IRRIGATION ENGINEERING DEPARTMENT

106 SOCIOLOGY, SOCIAL WORK & ANTHROPOLOGY DEPARTMENT

108 FISHERIES & WILDLIFE DEPARTMENT

110 RANGE SCIENCE DEPARTMENT

External Shape Of Enamel Crystals, H. Warshawsky

Scanning Microscopy

Biological hydroxyapatite crystals are either small, as in bone and dentin, or large as in enamel. Enamel crystallites are unique since each is initiated and grows in length, thickness and width until the entire layer of enamel is secreted. In maturation, these extremely long crystallites grow only in thickness and width. Crystal growth in vitro follows physico-chemical principles, but lacks biological intelligence; in vivo this intelligence is contributed by protein templates. The location of the organic template in enamel is congruent with the crystallite, constituting the crystal ghost. Since crystals cannot accommodate proteins, the explanation is logically inconsistent. In sections, …

X-Ray Microanalysis Of Cells In Suspension And The Application Of This Technique To The Study Of The Thymus Gland, A. Warley

Scanning Microscopy

Although X-ray microanalysis has become a well established technique in the study of tissues there are still relatively few papers reporting results from cells in culture. Our early investigations on freshly isolated murine thymocytes reported higher than expected concentrations of Na and Cl in these cells but subsequent studies have shown that these high concentrations are artefactual. Rat thymocytes that have been isolated and incubated for a short time to allow them to recover from the isolation procedure have lower concentrations of Na and Cl. Sections prepared from pellets of cells which have been concentrated by centrifugation in a microhaematocrit …

Adherent Platelets And Surface Microthrombi Of The Human Aorta And Left Coronary Artery: A Scanning Electron Microscopy Feasibility Study, B. O. Spurlock, A. B. Chandler

Scanning Microscopy

As part of a feasibility phase of an investigator-initiated multicenter NIH supported study on the Pathobiological Determinants of Athero-sclerosis in Youth (PDAY), we report observations on microthrombi and adherent platelets on the intima of the aorta and left anterior descending coronary artery. The long-term objective of this cooperative study is to define more precisely the pathogenesis of atherosclerosis during late childhood and early adulthood and to investigate the influence of selected risk factors known to be associated with clinically manifest disease in later life. Scanning electron microscopy (SEM) was utilized to survey broad areas of arterial intima. Of 109 specimens …

Advanced Vacuum Systems For Analytical Electron Microscopy, G. S. Venuti

Scanning Microscopy

Recent technological advancements such as significantly improved power supply stability and polepiece design, as well as increased accelerating voltage all contribute to the primary objective of the scanning electron microscope (SEM): higher resolution. Similarly, the advent of analytical electron microscopy (AEM) has also expanded the scope of applications to include energy-dispersive spectrometry, wavelength-dispersive spectrometry, and electron probe analysis. Specimen contamination and damage has become increasingly problematic as SEMs are used as analytical instruments. In an effort to minimize contamination and etching, and thereby benefit from these advances, cleaner and more efficient vacuum systems are required. Such benefits were realized when, …

Cell Wall Wrinkling And Solute Leakage In Imbibing Squash And Carrot Seeds, Vandy Cavdek, John N. A. Lott, Patrice Kerr

Scanning Microscopy

Dry seeds placed in an aqueous solution take up water, swell, and leak potassium and a variety of other materials into the solution. It is likely that much of the potassium is from the cell walls. Neutron activation analysis was used to measure the concentration of potassium leaked from both squash embryos and carrot mericarps that had been soaked in solutions of different water content. The cell walls in dry seed tissues are often wrinkled, whereas imbibed tissues have smooth cell walls. Cryogenic preparation for scanning electron microscopy was used to study the degree of cell wall wrinkling in the …

Scanning Electron Microscopy Of Vascular Smooth Muscle Cells From Rat Muscular Arteries, William J. Krizmanich, Robert M. K. W. Lee

Scanning Microscopy

The use of scanning electron microscopy (SEM) for the examination of medial smooth muscle cells (SMC) is limited by the presence of connective tissue mass in the adventitia obscuring the detailed structure of the SMC. This study deals with the description of a method which selectively removes the connective tissue, allowing three dimensional observation of SMC using SEM. A number of methods were tried. One method involving post fixation with 2% Os0₄ used in conjunction with HCl proved most successful in removing the extracellular matrix of large mesenteric arteries from spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto normotensive rats …

Preservation Of In Vivo Morphology Of Blood Vessels For Morphometric Studies, Robert M. K. W. Lee

Scanning Microscopy

Preservation of in vivo morphology of the blood vessels is important for morphometric studies. With each fixation method (e.g., immersion fixation, perfusion fixation), there are inherent pitfalls which can easily distort vessel wall morphology, thereby creating artifacts. Alteration of the vessel wall cell volume due to tissue preparation is another common source for errors. Selection of proper morphometric protocols for comparative studies is crucial. Lack of attention in these areas is a cause of confusion and contradiction in the literature. In this review, the merits of various commonly used methods for vessel wall preparation and measurements are discussed.

Surface Studies Of Calcium Oxalate Dihydrate Single Crystals During Dissolution In The Presence Of Urine, M. Akbarieh, B. Dubuc, R. Tawashi

Scanning Microscopy

Single crystals of Calcium Oxalate Dihydrate (COD) were grown from solution under controlled release of the reacting ions. Dissolution of COD was studied at different pH levels and in different dilutions of urine. The descriptors of the contour were determined during dissolution of COD using a quantitative morphological technique. The shape parameters and surface ruggedness were determined from Fourier and fractal analysis. The results obtained give quantitative information on the dissolution kinetics and the surface geometry of COD crystals in normal and diluted urine. Dissolution inhibition and morphological changes of COD crystals during dissolution were attributed to selective adsorption of …

Multiplane Sectioning And Scanning Electron Microscopy As A Method For Studying The Three-Dimensional Structure Of Mature Dental Enamel, S. Risnes

Scanning Microscopy

A method is described where teeth are sectioned/ground along at least two planes, etched, and viewed at various angles in the SEM in order to study the three-dimensional structure of enamel. This multiplane sectioning-scanning electron microscopy (MPS-SEM) method has been applied to the study of rat and human enamel. The method demonstrates in a direct way the complex three-dimensional structure of rat incisor enamel; the path of prisms and the distribution of interprismatic substance. The different appearance of alternate prism rows as seen in the longitudinal plane is seen to be due to prisms in alternate rows being inclined to …

Analysis Of Clean Transition Metal Surfaces By Core Level Spectroscopy, M. C. Desjonquères, D. Sébilleau, G. Tréglia, D. Spanjaard, C. Guillot, D. Chauveau, J. Lecante

Scanning Microscopy

The shifts in the binding energy of core electrons detected by high resolution X-ray photoelectron spectroscopy are a very sensitive probe of the chemical bonding of the excited atom. Since the surface atoms have their geometrical environment perturbed, their core levels are shifted from their bulk positions. A very large number of experiments have been performed on the 4f core level positions of tantalum and tungsten for various orientations of the surface plane. Systematic trends have been put forward and explained by theoretical models. Furthermore, the analysis of the angular variation of the core level line intensities gives structural information …

Studies On The Occurrence And Elemental Composition Of Bacteria In Freshwater Plankton, K. N. Booth, D. C. Sigee, E. Bellinger

Scanning Microscopy

The occurrence and cation content of bacteria in a eutrophic freshwater lake (Rostherne Mere, Cheshire, UK) were investigated over a one year sampling period in relation to cation changes in the lake surface water and phytoplankton.

Scanning electron microscope examination of trawl-net and filtered samples demonstrated bacterial association with Anabaena, Aphanizomenon and diatoms. Direct counts of associated and unassociated bacteria showed that increases in bacterial population relate to population decline of major algal constituents.

Spectrophotometric determination of selected cation levels in the lake water demonstrated wide fluctuations throughout the sampling period, with elevated levels of transition metals before and at …

The Fine Structure Of The Human Placental Villus As Revealed By Scanning Electron Microscopy, G. J. Burton

Scanning Microscopy

Scanning electron microscopy of the placenta has a history of only twenty years. During that time, however, there have been dramatic advances in instrument technology coupled with the refinement of preparative techniques designed to reduce fixation artifacts to a minimum. As a result many of the early claims must be amended or suitably qualified, and this is one aim of the present review.

Much new data on the internal structure of the placental villus is also presented. By means of the partial digestion technique it is now possible to describe the three dimensional configuration of the various components of the …

Electron Probe Micro-Analysis And Laser Microprobe Mass Analysis Of Material Leached From A Limestone Cathedral, L. A. Leysen, J. K. De Waele, E. J. Roekens, R. E. Van Grieken

Scanning Microscopy

Electron probe X-ray micro-analysis (EPXMA) and Laser microprobe mass analysis (LAMMA), were applied to characterize the leachate of sandy limestones of a Belgian cathedral.

Individual suspended particles, found in water that was sprayed over the cathedral walls ("1 each ate water"), were sized and analyzed by automated EPXMA-analysis, and classified with hierarchical cluster methods. LAMMA was used to gather more information about particles, present in the solution, as well as in suspension.

It was found that the leachate from black walls, had a high sulphate concentration and a large variety of particles in suspension, with different morphology and composition, with …

The Effects Of Low Doses Of Ionizing Radiation Upon The Micromorphology And Functional State Of Cell Surface, Z. Somosy, Tamara Kubasova, G. J. Köteles

Scanning Microscopy

The cellular membrane as one of the targets of ionizing radiation might play an important role in the development and modification of radiation-induced alterations after low doses. The present paper reviews the micromorphological and functional changes of plasma membranes of irradiated blood and cultured cells with special emphasis on the surface conditions: lectin binding, negative surface charges. The review is completed by our own studies on distribution of positive surface charges and the bindings of two lectins, the Concanavalin A and the wheat germ agglutinin. It was found that the decrease of negative surface charges is unconcomitant with appearance of …

Identification Of Non-Denuding Endothelial Injury By Scanning Electron Microscopy, M. Richardson, A. Parbtani

Scanning Microscopy

Endothelial injury is important in the development of arterial disease. To examine the response to endothelial injury it is necessary to recognise if endothelium has been altered and how this relates to normal function. Of the several methods available to evaluate endothelial integrity, ultrastructural examination has certain advantages. In particular, scanning electron microscopy of the endothelium will permit large areas to be examined, and changes can be related to the overall anatomy of the vessel.

There is good evidence that endothelial injury does not inevitably result in endothelial cell loss and denudation of the subendothelium, but that endothelial cells can …

Interpretation Of Electron Micrographs, B. A. Afzelius

Scanning Microscopy

Courses in electron microscopical techniques should include training in the active reading of electron micrographs. The student should be made aware of the fact that every micrograph contains a wealth of information, evident and hidden, and that a careful inspection is required to retrieve the information. More time should normally be spent in scrutinizing the micrograph than in its manufacture. Active reading of the micrograph is aided by a curiosity in the functional significance of the various details of the picture; there has to be a dialogue between the mind and the eye concerning the structural elements and their significance. …

Scanning Transmission Ion Microscopy As It Complements Particle Induced X-Ray Emission Microanalysis, H. W. Lefevre, R. M. S. Schofield, J. C. Overley, J. D. Macdonald

Scanning Microscopy

The early uses of Scanning Transmission Ion Microscopy (STIM) with MeV ions are reviewed. The transformation of STIM energy-loss images into maps of areal density is discussed, and is illustrated with images of a fruit fly head (Drosophila melanogaster). Freeze-dried male heads are transparent to 4-MeV protons in the dorsal and frontal directions, but in the sagittal direction the brain is opaque. STIM with molecular ions is shown to be useful for increasing contrast in low density areas. For recording registered STIM and PIXE images without changing accelerator parameters, apertures are used to accomplish the required change in beam intensity …

Endothelialization Of A New Dacron Graft In An Experimental Model: Light Microscopy, Electron Microscopy And Immunocytochemistry, G. Pasquinelli, P. Preda, T. Curti, M. D'Addato, R. Laschi

Scanning Microscopy

Two types of synthetic vascular grafts, Dacron Triaxial and Dacron Gelseal Triaxial, were implanted into both the common carotids of sheep. The animals were sacrificed 1, 2, 8, and 16 weeks after surgery. Multiple specimens, obtained from grafts and anastomoses, were studied by light microscopy, transmission and scanning electron microscopy. A parallel immunocytochemical analysis was performed on some specimens. Dacron Triaxial grafts failed to develop a complete neointimal coverage. Myofibroblasts and fibroblasts were the dominant cells in such synthetic graft. Moreover, focal areas of stripping, platelet deposition, and thrombosis were observed at 8 and 16 weeks.

In contrast, a stable …

Identification Of Actinobacillus Spp Cell-Surface Antigens Using Monoclonal Antibodies, Kall S. Symons

Undergraduate Honors Capstone Projects

Though a senior project is required for graduation from U.S.U. with the Honors Program, there are no written guidelines describing the requirements of a U.S.U. Honors Senior Project. This proposal seeks to show how the present research project from the College of Agriculture should meet the intended project requirements of the Honors Director.

Cell Polarity And Water Transport In Thyroid Epithelial Cells In Separated Follicles In Suspension Culture, Lucio Nitsch, Seymour H. Wollman

Scanning Microscopy

Separated thyroid follicles maintained in suspension culture can be used to study the properties of thyroid epithelium in the virtual absence of other cell types and to study the effect of extracellular materials on the follicles. They can be prepared by enzymatic separation of thyroid into single cells followed by reaggregation of the epithelial cells and also by collagenase treatment of thyroids to release follicles and sheets of epithelia that can be separated from other materials by differential filtration. The follicles can exist with normal orientation or inverted (inside out). The follicles are inverted in the presence of high serum …

Ultrastructural Analysis Of Dynamic Cellular Processes: A Survey Of Current Problems, Pitfalls And Perspectives, Helmut Plattner, Gerd Knoll

Scanning Microscopy

Dynamic phenomena in cells that can be analyzed on the ultrastructural level comprise so different aspects as ion shifts, conformational changes of macromolecules, membrane particle rearrangements, lipid phase transitions, protein--protein interactions (notably ligand-receptor interactions, including their sorting and sequestration), reversible membrane-to-membrane contacts, membrane fusions, transcellular transport phenomena, restructuring of cytoskeletal elements, ciliary and flagellar beat, cell shape changes, etc. Only some of these phenomena can be analyzed under stationary conditions, while others are unidirectional and sometimes very rapid. Therefore, the methodical approaches to be used (primary methods and follow-up procedures) might be widely different. Quite different methods are available, such …