Biology Commons^™

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 …

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 …

Old-Field Succession On A Minnesota Sand Plain, R S. Inouye, Nancy J. Huntly, D Tilman, J R. Tester, M Stillwell, K C. Zinnel

Biology Faculty Publications

Vegetation and soils were sampled in 22 old fields ranging in age from 1 to 56 yr since abandonment. Soil nitrogen concentration increased significantly with field age. Vegetation cover, total aboveground plant biomass, and litter cover increased significantly with soil nitrogen. Light penetration to the soil surface was negatively correlated with total plant biomass. Field age and soil nitrogen concentration were used as independent variables in simple regression and partial correlation analyses to determine the relative importance of such time—dependent processes as dispersals vs. the availability of a limiting resource (nitrogen) as predictors of patterns in species richness or the …

Influence Of Rufuging Consumers (Pikas: Ochotona Princeps) On Subalpine Meadow Vegetation, Nancy J. Huntly

Biology Faculty Publications

Talus slopes in western North America frequently are bordered by vegetation that differs in biomass, cover, height, and species composition from vegetation located farther from talus. These areas are grazed by pikas (Ochotona princess, which nest in that talus. Foraging theory predicts that pikas will produce a gradient of grazing pressure, which could produce the observed vegetational zonation. In a subalpine meadow in west-central Colorado, pikas produced the predicted gradient of grazing pressure, along which plant groups varied clinally in abundance. The effects of pikas on talus-border vegetation were tested by excluding pikas from small plots at several distances from …

Mapping Solid Surfaces With A Raman Microprobe, P. M. Fauchet

Scanning Electron Microscopy

By combining an optical microscope with a standard Raman scattering apparatus, information on the structure, composition, homogeneity, and stress state of solids can be obtained with one micron resolution. After a discussion of the advantages and implementation of the technique, we examine specific applications mostly taken from our own work dealing with laser-solid interactions. In particular, we examine the structural modifications produced during laser annealing of semiconductors and laser induced damage of thin films.

Ion-Induced Auger Emission From Solid Targets, Josette Mischler, Nicole Benazeth

Scanning Electron Microscopy

We present a review of the Auger emission induced from light elements (Mg, Al, Si) bombarded by ions of intermediate energy (1 keV - 200 keV). The different physical phenomena at the origin of Auger emissions are outlined, in particular the mechanism of molecular excitation responsible for the production of inner-shell vacancies in collisions between two complex particles and the processes of Auger decay and electron transport in the solid. Auger spectra partially consist of L₂₃VV electrons corresponding to decays in the bulk; this part is similar to that observed from electron-induced Auger spectra. Superimposed on this broad …

Capacitive Coupling Voltage Contrast, S. Görlich, K. D. Herrmann, W. Reiners, E. Kubalek

Scanning Electron Microscopy

Capacitive coupling voltage contrast (CCVC) allows electron-beam testing of passivated integrated circuits (IC) without radiation damage or prior, time-consuming specimen preparation. This effect occurs when low primary electron energies are used and the electron yield of the passivation layer is greater than 1. Signal changes in the relevant interconnections are transferred to the passivation surface via capacitive coupling, but they vanish there within the storage time due to electron irradiation. A physical model explains the dependence of CCVC on three parameters: electron irradiation, the passivation material and the signals within the IC. Computer simulations based on this model describe the …

Low Energy Electron Diffraction With Microscopic Resolution, J. Kirschner, T. Ichinokawa, Y. Ishikawa, M. Kemmochi, N. Ikeda, Y. Hosokawa

Scanning Electron Microscopy

We report on the development of a Scanning Low Energy Diffraction Microscope, operating in the range of 250 to 1000 eV primary energy. By discriminating against inelastically scattered electrons, low energy electron diffraction (LEED) patterns are obtained from areas of about 100 nm in size. By selecting a particular diffracted beam dark-field images of the surface structure are obtained in the scanning mode. Examples are given for polycrystalline Si and clean and adsorbate covered Si (111) surfaces.

Electron Detectors For Electron-Beam Testing Of Ultra Large Scale Integrated Circuits, S. C. J. Garth, D. F. Spicer

Scanning Electron Microscopy

The increasing density of components in integrated circuits imposes severe constraints on conventional electron beam testers. The use of electron detectors consisting of combined electrostatic and magnetic fields has demonstrated improved performance over conventional electrostatic detectors. Such detectors also ease many of the practical difficulties associated with electron beam testing of Ultra Large Scale Integration (ULSI) circuits. A detector using a single pole magnetic lens will be described and compared to detectors which use only electrostatic fields. The single pole lens detector has demonstrated superior performance to the electrostatic detector in terms of local field error and imaging resolution, allowing …

Charging Effects In Low-Voltage Scanning Electron Microscope Metrology, M. Brunner, R. Schmid

Scanning Electron Microscopy

Low voltage operation of the scanning electron microscope is being increasingly used to avoid negative charging in e-beam inspection and metrology. Positive charging effects, however, may still disturb the measurement accuracy even with low primary beam energies. Current investigations have revealed that no errors due to positive charging occur on resist structures on semiconductor substrates. But samples with metal structures on insulating substrates do involve disturbing effects due to positive charging. The difference in behavior between these groups of samples is attributed to the fundamental difference between insulator and conductor charging. This difference is due to different field geometries on …

Auger Microprobe Temperature Profiles Of Contamination Residue On Single Crystal Ferrite Substrates, Christine Bisagni, Nina Veisfeld

Scanning Electron Microscopy

Single crystal manganese-zinc (MnO,ZnO.Fe₂O₃) ferrite wafers with a 50 Angstrom surface finish were subjected to a conventional cleaning procedure and then analyzed in a JAMP-10 Auger microprobe with an internal heating device. Three essential Auger peaks were monitored during the heating. Auger peak intensity vs. time profiles were obtained for the heating process. High vacuum heat treatment conditions were established for the preparation of these materials for use as substrates in UHV thin film growth.

The Use Of A Line Scan Ratemeter For The X-Ray Microanalytic Evaluation Of Membrane-Bound Histochemical Endproducts, Imre Zs.-Nagy, Valéria Zs.-Nagy

Scanning Electron Microscopy

Although X-ray microanalysis represents a useful tool for identifying electron dense histochemical end-products, quantitative microanalytic measurements are seriously hampered in the case of the activities of certain membrane-bound enzymes. For example, the electron histochemical methods revealing K⁺-dependent pNPPase activity result in a very fine, granular reaction product of lead phosphate. Therefore microanalytic, densitometric or similar evaluations of the reaction, even in semiquantitative terms are not practical by the usual procedures.

This paper describes a method of X-ray microanalysis of thick sections (0.5 μm) processed for K⁺-pNPPase, where a sufficient amount of lead is present for X-ray …

Applications Of X-Ray Microanalysis To The Study And Conservation Of Ancient Glasses, S. Hreglich, M. Verita

Scanning Electron Microscopy

X-ray microanalysis can be successfully applied to the study of the chemical composition and weathering processes of ancient glass. The problems concerned with this kind of application are considered. A verification is conducted of the accuracy and sensitivity of this technique, which are sufficient to obtain useful information on technologies and raw materials used and consequently on the origin and dating of ancient glasses.

This analytical method also discloses meaningful data for the optimization of restoration and the choice of appropriate conservation operations.

Correlative Scanning Electron Microscopy In The Study Of Human Gastric Mucosa, F. Bonvicini, M. C. Maltarello, P. Versura, D. Bianchi, G. Gasbarrini, R. Laschi

Scanning Electron Microscopy

We studied two aspects of the human gastric mucosa: - the surface morphology of mucous cells, as viewed by scanning electron microscopy (SEM); - the glycosidic components of intracellular mucins, characterized by means of lectins. The latter were conjugated with fluorescein isothiocyanate and with colloidal gold-silver for the visualization of the reaction products in light microscopy (LM) and in SEM (backscattered mode) respectively.

The surface morphology of mucous cells appears to be correlated to the secretory state.In gastric ulcers we found a prevalence of non-secreting cells. A decrease in glycosidic receptors for fucose-binding lectin and galactose-(l-3)-N-acetyl-galactosamine-binding lectin was also observed. …

High Resolution Scanning Auger Microscopy Of Mineral Surfaces, M. F. Hochella Jr., A. M. Turner, D. W. Harris

Scanning Electron Microscopy

There are a number of cases where scanning Auger microscopy can be used to determine the near-surface composition of minerals with extremely high lateral resolution. This involves collecting Auger spectra with reasonable signal to noise ratios without encountering significant beam induced charging or surface degradation, even if the beam is impinging on a grain less than 1μm in diameter. We typically use a 3 keV beam with less than 10 nA beam current on a sample surface that is tilted (to increase backscattered and secondary electron emission efficiency) and relatively flat. To further minimize surface degradation, vacuum levels are kept …

Quantitative Ion Microprobe Analysis Of The Rare Earth Elements In Minerals, Ghislaine Crozaz, Ernst Zinner

Scanning Electron Microscopy

The lanthanides or rare earth elements (REE) which are present in trace concentrations in rocks are most useful for investigating the origin of these objects. Of the microbeam techniques presently used to measure the REE concentrations of individual crystals, secondary ion mass spectrometry (SIMS) is the only method sensitive enough to allow the determination of REE abundances in most natural minerals. Usually, energy filtering is applied to remove all complex molecular interferences. All the REE, down to a level of ≤ 100 ppb, can be measured in spots 5 to 20 𝜇m in diameter. A growing number of studies involving …

Intrauterine Device (Iud) Associated Pathology: A Review Of Pathogenic Mechanisms, Waldemar A. Schmidt, Karmen L. Schmidt

Scanning Electron Microscopy

This paper summarizes our studies of IUD-related disease with those previously published by others. Our data are based upon 51 IUDs and 42 index cases of IUD-related disease demonstrating specific processes. Gross, dissecting microscope, scanning electron microscope and X-ray microanalysis examinations were made of selected IUDs and associated tissues. Tissue associated with the IUDs revealed inflammation in 59.4%, calcific material in 6.3% and no abnormality in 34.4%. JUD-associated tissue responses were accompanied by changes of the IUD; these changes involved deposition of substances upon the IUD surface and degradation of the JUD itself. Disintegration of the IUD, its string or …

Structural Features Of Isolated, Fractionated Bone Marrow Endothelium Compared To Sinus Endothelium In Situ, Seiji Irie, Mehdi Tavassoli

Scanning Electron Microscopy

Structural features of isolated, fractionated rat bone marrow endothelium were compared to those of marrow sinus endothelium in situ. Marrow endothelium was purified, first by density gradient sedimentation on Percoll and then subjected to centrifugal elutriation. Using antifactor VIII antibody staining (indirect immunofluorescent method), preparations of greater than 50% purified endothelium were obtained. By SEM, these cells were about 10 μm in size and showed smooth surface and numerous invaginations. These features were also observed in the in situ endothelium obtained by perfusion-fixation and freeze-cracking. In addition, in situ endothelium displayed numerous hemopoietic cells in migration through the endothelium. By …

Scanning Electron Microscopy Of The Microvascular System In The Inner Ear, Yoshiaki Nakai, Haruhiko Masutani, Hiromasa Cho

Scanning Electron Microscopy

In the present work, vessels casts in the inner ear of the rat and guinea pig, prepared by casting method using Mercox resin, were subjected to scanning electron microscopic examination and following results were obtained: 1) In adult guinea pig, numerous capillary nets were found in the following parts: stria vascularis, spiral ligament, spiral prominence, Corti's organ, spiral ganglion, plexus cochlearis, semicircular ampulla, saccule, utricle, and endolymphatic sac. These were consistent with functionally and morophologically important areas in the inner ear. 2) In the central side of the area with capillary nets, arterioles were found to run throughout, like a …

Scanning And Transmission Electron Microscopic Study Of Recovered Porcine Aortic Valved Conduits, D. J. Allen, I. H. Fentie, J. T. Davis, Angela Lineen

Scanning Electron Microscopy

Four explanted porcine aortic valved conduits were examined using scanning and transmission electron microscopy. Sources of obstruction such as neointima or "peel" and calcification were observed. In one sample the neointima was found to possess an unusually large expanse of squamous cells partially lining the luminal surface. This lining much resembled a normal endothelium, which is not an expected feature of neointima. Cells, presumably of host origin, were noted upon the leaflet surfaces. They did not seem as well organized as those found on the neointima. Calcification did not seem greatly advanced but was clearly apparent. Certain treatments proposed by …

Statoconia Formation In Molluscan Statocysts, Michael L. Wiederhold, Christine E. Sheridan, Nancy K. R. Smith

Scanning Electron Microscopy

The gravity sensors of all molluscs phylogenetically below the cephalopods are spherical organs called statocysts. The wall of the sphere contains mechanosensory cells whose sensory cilia project into the lumen of the cyst. The lumen is filled with fluid and dense "stones", the statoconia or statoliths, which sink under the influence of gravity to load, and stimulate, those receptor cells which are at the bottom. The statuconia of Aplysia californica are shown to be calcified about a lamellar arrangement of membranes. Similar lamellar membrane arrangements are seen within the receptor cells, and their possible role in the formation of the …

Cells From Xenopus Laevis Gastrulae Adhere To Fibronectin-Sepharose Beads And Other Lectin Coated Beads, Kurt E. Johnson, Michael H. Silver

Scanning Electron Microscopy

Cells from Xenopus laevis blastulae have a poorly developed ability to adhere to Sepharose beads covalently coupled to bovine plasma fibronectin (FN-beads). They do, however, have the ability to adhere to con A-beads and cytodex-1 and cytodex-3 beads. Beginning at the early gastrula stage, there is a progressively increasing ability of cells to adhere to FN-beads. Gastrula cells adhere to FN-beads by the formation of large ruffling lamellipodia. These cells can translocate on the surface of FN-beads; and when attached to both beads and the surrounding glass substratum of culture vessels, have the ability to move the beads extensively. Gastrula …

Adverse Effects Of Metals On The Alveolar Part Of The Lung, Anne Johansson, Per Camner

Scanning Electron Microscopy

Rabbits were exposed to low levels of metal dust or metal ions by inhalation for 1-8 months, 5 days/week and 6h/day. Following exposure lung tissue was examined by light and electron microscopy, the lung content of phospholipid was analyzed and the morphology and function of alveolar macrophages were investigated.

Metallic nickel dust as well as soluble nickel chloride produced accumulation of macrophages and laminated structures in alveoli and increased volume density of alveolar type II cells. The amount of phospholipids was elevated, mainly due to an increase in disaturated phosphatidylcholine. After one month exposure to metallic nickel dust or soluble …

Comparative Aspects Of Mammalian Spermiogenesis, Leif Plöen, Jean-Luc Courtens

Scanning Electron Microscopy

The testes of some different orders of eutherian mammals were examined by conventional electron microscopy with respect to their pattern of spermiogenesis. In addition, some of the testes were studied by cytochemical methods for demonstration of certain nuclear proteins and of glycoproteins in the acrosome and the plasma membrane of spermatids.

It was found that although the basic pattern of spermiogenesis was similar in all species studied, there were pronounced dissimilarities in the final shape of the spermatids. Differences were also observed in the timing of the differentiation of several organelles. The head of late spermatids and spermatozoa of Primates, …

Intracellular Structure Of The Outer Hair Cell Of The Organ Of Corti, Y. Harada, T. Sakai, N. Tagashira, M. Suzuki

Scanning Electron Microscopy

The intracellular structure of the outer hair cells of the normal guinea pig organ of Corti was investigated three dimensionally by scanning electron microscope. Freeze fracturing technique followed by maceration with a 0.1% OsO₄ solution (osmic maceration method) was used. Among the cell organelles, the endoplasmic reticulum (ER) showed the most interesting features, such as subsurface cisternae and lamellar bodies. The subsurface cisterna which formed a stratiform network covered the inner surface of the cell membrane and the stratiform structure disappeared at the infranuclear region. Variously shaped mitochondria (spherical, cylindrical and branched) were found on the innermost layer of …

Scanning Electron Microscopic Observation Of The Crista Ampullaris, Y. Harada, M. Takumida, N. Tagashira

Scanning Electron Microscopy

The crista ampullaris of the guinea pig and the bull frog were investigated by scanning electron microscopy. The crista ampullaris were freeze fractured or sheared followed by maceration with 0.1% OsO₄ solution. Following this, three-dimensional intracellular structures were observed. The mitochondria of the sensory cells varied in shape from globular to long and slender. Golgi apparatus and endoplasmic reticulum of the sensory cells were also demonstrated clearly. Nerve elements, nerve endings and synaptic structures were also observed stereoscopically.