Biology Commons^™

Surface Topographical And Compositional Characterization Using Backscattered Electron Methods, Dirk A. Wassink, Jerry Z. Raski, Joel A. Levitt, David Hildreth, Kenneth C. Ludema

Scanning Microscopy

Two pairs of diametrically opposed Schottky surface barrier diodes in a modified scanning electron microscope (SEM) are used to reconstruct surface elevations and composition differences. An empirically determined function of difference of signals from opposing diodes is used to calculate slopes, which are then integrated to elevations by an efficient 2-dimensional Fast Fourier Transform. Composition differences are distinguished by variations in the overall backscattered electron (BSE) intensity estimated by the sum of the four diode signals. Arithmetic average roughness measurements from the BSE device are within 10% of stylus surface tracer measurements when surface slopes average less than 6 degrees …

Electron Beam Induced Current Investigations Of Electrical Inhomogeneities With High Spatial Resolution, Eu. Yakimov

Scanning Microscopy

Electron beam induced current (EBIC) microscopy is a very promising SEM technique for the study of diffusion length and depletion region width inhomogeneities with high spatial resolution. However, this resolution is limited by the dimensions of the electron-hole pair generation region. In this paper the possibilities to improve spatial resolution are discussed. Electron beam tomography, i.e. the reconstruction of physical property distributions from sets of two-dimensional images, seems to be the most promising for this purpose. It is shown that in the case of dislocations it is possible to obtain information about dislocation impurity atmosphere parameters from EBIC measurements. The …

Micro-Pixe (Particle-Induced X-Ray Emission Analysis) Applications In Minerals Research, S. H. Sie, C. G. Ryan, G. F. Suter

Scanning Microscopy

The versatility of the PIXE method with microbeams of protons as a non-destructive, in-situ probe for trace element analysis in the geosciences has been demonstrated in an ever increasing number of cases. While in most applications the method can be considered as derivative or as an extension of electron microprobe methodology, features unique to the proton microprobe enable new approaches to hitherto intractable problems of analysis. An appropriate niche has been established in igneous mineralogy and petrology, with important implications both in the basic geosciences as well as mineral industry applications, particularly in the diamond exploration industry. This paper reviews …

The Development Of The Vascular System In Quail Embryos: A Combination Of Microvascular Corrosion Casts And Immunohistochemical Identification, M. C. Deruiter, B. Hogers, R. E. Poelmann, L. Vanlperen, A. C. Gittenberger-De Groot

Scanning Microscopy

Although vascular casts, obtained by injection with methacrylates, are frequently used to investigate the adult vascular system, little data are available for embryonic stages. In this paper we use Mercox^R in quail embryos in the period of 2 to 7 days after incubation. The microvascular corrosion casts were evaluated in the scanning electron microscope (SEM) with special attention to the development and remodelling of the large arteries and veins. Our results show that the remodelling of the large arteries and veins together with their developing tributary vessels can be visualized from very early embryonic stages onwards. However, complete replication …

Cellular Basis Of Aging In The Mammalian Heart, Piero Anversa, Joseph M. Capasso

Scanning Microscopy

This review is concerned with the functional and structural changes occurring in the aging heart. These changes were investigated in an integrated fashion in Fischer 344 rats at 4, 12, 20, and 29 months after birth. Mean arterial pressure, left ventricular systolic and end-diastolic pressures, as well as stroke volume remained substantially constant up to 20 months. At 29 months, however, end-diastolic pressure was significantly increased, and dP/dt and stroke volume were depressed. Focal areas of interstitial and replacement fibrosis were markedly increased at 20 and 29 months, mostly in the subendocardial region of the ventricular wall. Also the aggregate …

Microphotometric Quantification Of Crystal Growth In Gels For The Study Of Calcium Oxalate Urolithiasis, Wolfgang Achilles

Scanning Microscopy

This paper gives a review on an efficient microtechnique (Gel Crystallization Method; GCM) which quantifies crystal growth in gel matrices, and its application to research into urinary stone formation. Relative crystal growth rates (Vcr) of calcium oxalate hydrates (CaOx) were determined by simultaneous multiple measurements in 96-well microplates using computer controlled microscopic photometry. Efficiency: 120 kinetic measurements/h; imprecision: < 2% at standard conditions. The method was applied to study the effects of diverse small-ionic and macromolecular constituents of human urine on the crystal growth rate of CaOx. The 'inhibitory activity' of urine could be evaluated by comparison of the Vcr measured in native and corresponding artificial samples. Macromolecules, at physiological concentration, played only a minor role as inhibitors in the model under regard. The GCM was employed to study the in-vivo effects of different therapeutic measures on CaOx growth in urine of normal volunteers. While the application of alkali citrate resulted in a > 70% decline of Vcr, no beneficial effects could be found with three magnesium compounds, and a dietary fiber preparation. In a study including 20 male recurrent CaOx stone formers and 29 well-matched controls, among all parameters under investigation, the Vcr showed the …

Scanning Electron Acoustic Microscopy And Scanning Electron Microscopic Imaging Of Iii-V Compounds Devices, J. F. Bresse

Scanning Microscopy

Scanning electron acoustic microscopy (SEAM) and SEM infrared imaging (SEMIR) use both a modulated electron beam to generate thermal waves which produce acoustic waves detected by a transducer in the case of SEAM and affect the surface temperature which is directly monitored by the infrared emission. Both techniques are used to visualize non-adherence zones in III-V compounds devices. SEAM is applied to metallic layers like Au, Au-Ti, W-Mo-Ge deposited on a GaAs substrate. SEAM images are correlated with global adherence measurements.

SEMIR is applied to dielectric layers, like Si₃N₄/InP. An estimation of the surface temperature is …

The Role Of The Spleen In Lymphocyte Migration, R. Pabst, J. Westermann

Scanning Microscopy

In all species studied so far it was found that more lymphocytes migrate to the spleen than to all the lymph nodes together. Specific molecules on lymphocytes and endothelial cells regulate their entry into lymph nodes, but none of the known molecules play a role in homing to the spleen. The splenic compartments, comprising the red pulp, marginal zone, periarterial lymphatic sheath (PALS) and follicles, all show different kinetics for migrating lymphocytes. By combining ⁵¹Cr lymphocyte labeling with morphometry and two color immunohistochemistry, the migratory route of lymphocyte subsets can be followed through the spleen and absolute numbers of …

Microvascularization Of The Pleura In Rats And Guinea Pigs, S. Aharinejad, A. Lametschwandtner, P. Böck, P. Franz

Scanning Microscopy

The microvascularization of the visceral and parietal pleura was studied in rats and guinea pigs using vascular corrosion casts and scanning electron microscopy.

The visceral pleura was shown to be devoid of a vascular bed of its own. The capillary meshwork observed on the surface of the lung belongs to the pulmonary parenchyma. The parietal pleura, by contrast, possesses its own capillary network with an appropriate arterial supply and a venous drainage. The parietal pleural capillaries cover the costal regions completely, whereas the intercostal spaces are only provided by interspersed small patches of capillaries. That the feeding arteries of the …

Sphincters In The Rat Pulmonary Veins. Comparison Of Scanning Electron And Transmission Electron Microscopic Studies, S. Aharinejad, P. Böck, A. Lametschwandtner, P. Franz, W. Firbas

Scanning Microscopy

The microvasculature of the rat lung was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of vascular corrosion casts and tissue sections. Particular emphasis was placed on postcapillary venules, pulmonary venules and small pulmonary veins (small interlobular veins).

Casts of lung capillaries appeared inconspicuous with smooth surface. On the casts of pulmonary venules and small pulmonary veins, by contrast, series of narrow annular constrictions, present at regular distances of 20-25 μm, were seen. These constrictions may be drastic, narrowing down the caliber of the vessel up to 50%. In the constrictions the marks of circularly running tubular …

The Matrix Of Urinary Tract Stones: Protein Composition, Antigenicity, And Ultrastructure, J. P. Binette, M. B. Binette

Scanning Microscopy

We have extracted proteins from urinary tract stones by electrodialysis and have developed antisera to the core and the shell of a renal stone. The protein composition varies between stones but is identical in the core and the shell of the same stone. One stone antigen is present in the urine of normal individuals and stone formers, as well as in cholesterol gallstone extracts. Electron microscopy of the core of a urate-calcium oxalate stone before and after demineralization reveals a fibrillar structure associated with mineral deposits, as well as aggregates of crystals.

A Theory And Monte Carlo Calculation On Low Energy Electron Scattering In Solids, Yen-Cai Ho, Zheng-Yu Tan, Xin-Lei Wang, Jia-Guang Chen

Scanning Microscopy

Low energy electron scattering (LEES) courses in solids are described by using a strict theory and direct simulation method proposed in this paper: we have improved Pendry's method based on the partial wave expansion, which can be applied to calculate the elastic scattering between an electron and atoms. The contributions of shell electrons, conductive electrons and plasma excitations are considered in the calculation of the inelastic scattering; electron scattering and cascade process of secondary electrons are simulated by Monte Carlo method. The secondary electron yields, the energy spectra curve and the backscattering electron coefficients for Cu were evaluated at the …

Scanning Tunneling Microscope Images Of Adenine And Thymine At Atomic Resolution, M. J. Allen, M. Balooch, S. Subbiah, R. J. Tench, W. Siekhaus, R. Balhorn

Scanning Microscopy

The scanning tunneling microscope has been used to obtain images of DNA that reveal its major and minor grooves and the direction of helical coiling, but sufficient resolution has not yet been achieved to identify its bases. To determine if this technology is capable of identifying individual DNA bases, we have examined the molecular arrangements of adenine and thymine attached to the basal plane of highly oriented pyrolytic graphite. Both molecules form highly organized lattices following deposition on heated graphite. Lattice dimensions, structural periodicities, and the epitaxy of adenine and thymine molecules with respect to the basal plane of graphite …

The Effect Of Bacterial Endotoxin Upon The Morphology Of The Tectorial Membrane And Stereocilia In The Guinea Pig Cochlea, S. D. Comis, M. P. Osborne, M. J. Tarlow

Scanning Microscopy

Endotoxin of E coli was microperfused into scala tympani or injected into the cerebrospinal fluid in anaesthetised pigmented guinea pigs. The effects of endotoxin on the cochlea were studied using electrophysiological techniques and scanning electron microscopy. We found a drop in the amplitude of the cochlear microphonics and compound action potentials 2 to 2.5 hours after injection. There were also changes in the morphology of stereocilia and the tectorial membrane. The stereocilia lost their rigidity and the tectorial membrane appeared swollen. These effects were less severe in animals which were pretreated with dexamethasone.

Effects Of Photosensitization And Low-Power Helium-Neon Laser Irradiation On Liposomes And Cell Membranes, Timea Berki, P. Németh, L. Pótó, A. Németh

Scanning Microscopy

Low-power He-Ne laser irradiation causes a well-defined and energy dependent cell destruction of in vitro cultured cell lines sensitized by hematoporphyrin derivative (HPD). The mechanism of this photosensitization was studied by measuring with polarization microscopic, scanning electron microscopic, and electron-spin-resonance (ESR) spectroscopic parameters. The cell damage caused by photosensitization and laser irradiation seems to be a complex process, however the biological membranes seem to be one of the primary targets. The energy of laser light causes rotation and resonance changes of macromolecules and the water molecules, resulting in an increased structural order of the submembraneous components in the living cells, …

The Scanning Electron Microscope: How Valuable In The Evaluation Of Small Bowel Mucosal Pathology In Chronic Childhood Diarrhea?, J. Rainer Poley

Scanning Microscopy

Data are presented on scanning electron microscopy (SEM) on small intestinal biopsies of children with chronic diarrhea. In particular, there were 230 patients aged 3 months to 13 years with the following diagnoses: chronic nonspecific diarrhea, cow's milk protein intolerance, soy protein intolerance, giardiasis, cystic fibrosis, gluten-sensitive enteropathy, isolated lactase deficiency, isolated sucrase-isomaltase lactase deficiency, microvillus inclusion disease, rotavirus ententis, protracted diarrhea of infancy, chylomicron retention disease, visceral myopathy and villous asthenia.

Examination of biopsied intestinal mucosa by SEM has yielded important new information and insights on structural pathology and ultrastructural topography. Many of the observed changes helped to better …

Scanning Electron Microscopy Of High-Modulus Polyethylene Fibres, N. H. Ladizesky, M. K. M. Pang

Scanning Microscopy

Scanning electron microscopy (SEM) examination of high modulus polyethylene (HMPE) fibres gives rise to a number of artifacts which are here recognized. Antistatic agents may be successfully used for the observation of the woven fibres, but only in conjunction with an intermediate metallic coating. For isolated threads superior results are obtained with the metallic coating alone.

New SEM evidence suggests that the high density of surface cracks produced by plasma treatment of HMPE fibres is associated with an aging process. This can also be activated by mechanical energy or storage at room conditions.

Hereditary Hair Changes Revealed By Analysis Of Single Hair Fibres By Scanning Electron Microscopy, B. Forslind, M. K. Andersson, E. Alsterborg

Scanning Microscopy

In many disorders with a genetic background the sparsity of scalp hairs may deter the clinician from trying to extract information from single hair fibres. Presenting a number of diverse conditions, we propose to show that simple measures can be taken in the doctor's office which makes single fibre analysis a useful tool for assessment of factors involved in genetic disorders including the integument and its appendages. The paper is focussed on the utilization of the scanning electron microscope with the goal of demonstrating that pertinent information can be gained where information from transmission electron microscopy and other techniques are …

Morphological Correlates Of Mechanotransduction In Acousticolateral Hair Cells, J. O. Pickles, G. W. Rouse, M. Von Perger

Scanning Microscopy

The development of ideas on mechanotransduction in acousticolateral hair cells is described, leading to the current idea that transduction depends on deflection of the bundle of stereocilia by a force parallel to the plane of the sensory epithelium. Electrophysiological experiments are summarised, suggesting that transduction depends on a shear between the different rows of stereocilia, and that the transducer channels are situated towards the tips of the stereocilia. Analysis of the ways that shear between the rows of stereocilia could be detected suggests that tip links are the structures which are most likely to transmit the stimulus-induced forces to the …

Three Dimensional Intracellular Structure Of The Cochlea Using The A-O-D-O Method, A. Nagasawa, R. V. Harrison, R. J. Mount, Y. Harada

Scanning Microscopy

We have observed the three-dimensional intracellular structure of the organ of Corti and the spiral ganglion of the chinchilla using the aldehyde osmium-DMSO-osmium (A-O-D-O) method, and compared our findings with previous studies in the guinea pig. In cells of the spiral ganglion and the organ of Corti, microtubules and other cytoplasmic filaments were digested by OsO₄ during processing to provide a clear view of membranous structures such as mitochondria, endoplasmic reticulum and Golgi apparatus. The appropriate digestion time with 0.1% OsO₄ solution was found to be 60-80 hrs for the organ of Corti and 70-90 hrs for the …

Scanning Electron Microscopy To Establish The Marble Weathering Mechanism In The Alhambra Of Granada (Spain), M. A. Bello, L. Martín, A. Martín

Scanning Microscopy

The weathering processes of the white marble from Macael quarries (Almeria, Spain) used in the Alhambra of Granada have been studied with the aim of establishing the weathering factors and mechanism. Unaltered quarry samples have been submitted to diverse accelerated weathering experiments and their morphology compared to the altered materials from the monument. The weathering process stages have been established and the degree of weathering in some monumental dependencies evaluated.

Proton Induced X-Ray Emission Analysis Of Biological Specimens - Past And Future, B. Forslind, K. G. Malmqvist, J. Pallon

Scanning Microscopy

Proton induced X-ray emission (PIXE) analysis is a comparatively new member of the family of spectrographic methods. In the last decade PIXE techniques have been applied to biological problems with great success. This review gives a condensed presentation of recent developments in biological (medical, zoological, and botanical) applications of PIXE analysis with special focus on factors which commonly influence the results, such as calibration, contamination, and preparation. The great advantage of PIXE analysis in studying physiologically important trace elements such as Zn, Mg, Fe, and Cu is underlined. Elemental mapping not only allows quantitative elemental analysis, but can also demonstrate …

Effects Of Modulated And Continuous Microwave Irradiation On The Morphology And Cell Surface Negative Charge Of 3t3 Fibroblasts, Z. Somosy, G. Thuróczy, T. Kubasova, J. Kovács, L. D. Szabó

Scanning Microscopy

Mouse embryo 3T3 cells were irradiated with 2450 MHz continuous and low frequency (16 Hz) square modulated waves of absorbed energy ranging from 0.0024 to 2.4 mW/g. The low frequency modulated microwave irradiation yielded more morphological cell changes than did the continuous microwave fields of the same intensity. The amount of free negative charges (cationized ferritin binding) on cell surfaces decreased following irradiation by modulated waves but remained unchanged under the effect of a continuous field of the same dose. Modulated waves of 0.024 mW/g dose increased the ruffling activity of the cells, and caused ultrastructural alteration in the cytoplasm. …

The Measurement Of Aluminum Surface Diffusion On Si, Sio2, And Si3n4 By Scanning Auger Microscopy, L. L. Levenson, A. B. Swartzlander, A. Yahashi, H. Usui, I. Yamada

Scanning Microscopy

The diffusion distance of Al atoms on Si(111), SiO₂, and Si₃N₄ substrates has been measured as a function of substrate temperature. These studies were carried out by depositing Al from an effusive source and from an ionized cluster beam source. Both sources were used in the same apparatus at different times. The deposition was carried out with either a slit mask or a wire mask at the substrate. After the masks were removed, the deposit was examined by optical and electron microscopy, mechanical profilometer, and Auger line scans. The diffusion distance of Al on the …

Enhancing The Laser Scanning Confocal Microscopic Visualization Of Lucifer Yellow Filled Cells In Whole-Mounted Tissue, David L. Becker, Joanna Dekkers, Roberto Navarrete, Colin R. Green, Jeremy E. Cook

Scanning Microscopy

The laser scanning confocal microscope (LSCM) is an extremely useful tool that allows fluorescently labelled cells to be visualized in whole-mount preparations. This is particularly advantageous, for example, in studying the dendritic trees of neurons with respect to their environment.

One of the most popular, and easiest, ways to visualize a cell is to inject it intracellularly with the fluorophore Lucifer Yellow (LY). However, the argon gas lasers of most LSCM's are not well matched to the excitation spectrum of aqueous LY. When this largely inappropriate excitation is combined with standard filters, designed for fluorescein fluorescence rather than Lucifer Yellow, …

The Vascularization Of The Digestive Tract Studied By Scanning Electron Microscopy With Special Emphasis On The Teeth, Esophagus, Stomach, Small And Large Intestine, Pancreas, And Liver, S. Aharinejad, A. Lametschwandtner, P. Franz, W. Firbas

Scanning Microscopy

The periodontal vessels in adult rats show a ladder-like pattern; in guinea pigs molars, by contrast, they present a honey-comb pattern. The vascular architecture in human teeth seems to be similar to that of rabbits. In guinea pigs, rats, rabbits and humans esophagus circumferential vessels give off perforating vessels. In human esophagus the number and diameter of the vessels in the submucous venous plexus decrease from proximal to distal. In the stomach the subepithelial capillary network shows a honey-comb pattern reflecting the arrangement of the gastric pits. A local portal system between the gastric glands and the surface mucosal cells …

Preparation And Characterization Of Some Particulate Materials In The Aluminum Industry, A. Csordás-Tóth, B. Szikora, J. Kürthy-Komlósy, I. Tassy

Scanning Microscopy

Preparation and characterization techniques for the following particulate materials are reviewed: micromineralogical samples of bauxite, alumina and its trihydroxide, as well as sedimentary and respirable particles. Scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDS) and image analysis were used to characterize the microminerals of bauxite. Comparisons were made among micromineralogical samples with various grain size fractions and the degree of weathering could be quantified. Programs were developed for characterization of the sandy and floury types of aluminum trihydroxide and alumina. We have used backscattered electron SEM images to characterize the size and shape of various aluminum trihydroxides. Comparison could …

Heterogeneity Of Crystals Attached To The Human Enamel And Cementum Surfaces After Calculus Removal In Vitro, T. Kodaka, K. Debari, M. Yamada

Scanning Microscopy

Twenty one extracted human teeth with dental calculi on the enamel and cementum surfaces, fixed in 10% neutral formaldehyde, were selected for this study. After ethanol dehydration and air drying, these calculi were removed by tweezers to observe the teeth surfaces under them. The inspection of these surfaces using SEM and EDX revealed hexahedrally based crystals including pseudocuboidal, rhombohedral and variable rugged rocky shapes. These crystals were identified as Mg-containing whitlockite. The pseudocuboidal crystals, measuring about 4.5 μmin maximum length, were widely distributed on the cervical enamel surface previously covered by calculus. On the root surface, however, these areas decreased …

Elemental Analysis And Fine Structure Of Mitochondrial Granules In Growth Plate Chondrocytes Studied By Electron Energy Loss Spectroscopy And Energy Dispersive X-Ray Microanalysis, Joanna Wroblewski, Romuald Wróblewski, Claudie Mory, Christian Colliex

Scanning Microscopy

Electron energy loss spectrometry - EELS, and energy dispersive X-ray microanalysis - XRMA, were used to study the elemental composition of mitochondrial dense granules - mdg. The study was performed on dry cut thin sections (80-200 nm) of freeze-dried and low temperature embedded cartilage. Results obtained by means of XRMA clearly showed high phosphorus and calcium content in the mdg. Using EELS at 100 kV primary voltage we found that small concentrations of elements (i.e. below typically 1% atomic weight) are difficult to analyze and map, this especially in sections thicker than 50-60 nm. Surprisingly, analysis of calcium can be …

In Vitro And In Vivo Replication For Scanning Electron Microscopy Of The Cervical Region Of Human Teeth, Joan Bevenius, Kjell Hultenby

Scanning Microscopy

A replica technique for scanning electron microscopy (SEM) of the cervical region of human teeth was evaluated on extracted premolar teeth by comparing the replicas and the original specimens in the SEM. For in vivo application, the technique was modified to circumvent contamination by saliva and gingival exudate. Impressions were taken with an addition silicone polyvinylsiloxane material and the replicas were poured in epoxy resin die material. A surface active dentine conditioner facilitated flow of the impression material into irregular surface areas; in vivo a scavenger impression was used to remove surface debris. Custom trays were made of light-cured acrylic …