Life Sciences Commons^™

Comparison Of Preparative Techniques For Scanning Electron Microscopy Examination Of Soybean Seed Coats In Sectional View, Daniel M. Baker, Harry C, Minor, Merton F. Brown

Scanning Electron Microscopy

Various scanning electron microscopy preparative techniques have been used by researchers to examine sectional views of dry, mature soybean (Glycine~ CL.) Merr.) seed coats. Such previously employed techniques were utilized In our preliminary investigations of seed coat structure, but often yielded unacceptable preservation. Consequently, eight preparative techniques were evaluated In an effort to define conditions required to obtain consistently high quality preservation of soybean seed coats In sectional view. Of the eight procedures tested with the cultivar Williams 82, razor sections and mechanical fractures of dry seed coats yielded the poorest definition of anatomical features. Samples soaked In water prior …

Long Term Effects Of Radiation And Combined Modalities On Mouse Lung, David P. Penney, Paul Van Houtte, Dietmar W. Siemann, Wayne A. Rosenkrans Jr., Philip Rubin, Robert A. Cooper Jr.

Scanning Electron Microscopy

The lung appears to be the major dose-limiting organ in radiation of the thorax. Early responses (<1 week) involve the type II pneumocyte and increased surfactant biosynthesis and secretion. Later changes, which appear to be related to the surfactant response, lead to classical radiation pneumonitis, which is often fatal. Animals which survive radiation pneumonitis develop progressive fibrosis, a late-appearing response, which reduces compliance and available air space, and is usually fatal. This study centers on the fine structural changes in the lungs of LAF₁ mice, 63 weeks following various radiation exposures (5-13 Gy). Doses which are subthreshold in evoking surfactant and pneumonitic responses precipitate fibrosis and atelectasis by 63 weeks, and involve type II pneumocyte sloughing and degeneration. Of the two major deterrents to lung irradiation (pneumonitis and fibrosis), these results suggest that fibrosis always follows pneumonitis, but pneumonitis is not a necessary preliminary step to fibrosis. Bleomycin elicits several morphological alterations characteristic of radiation, and, when combined with the latter, appears to exacerbate radiation effects.

Characterization Of Small Metallic Clusters By Electron Energy Loss Spectroscopy, M. Acheche, C. Colliex, P. Trebbia

Scanning Electron Microscopy

Small spherical tin and gallium clusters (diameters in the range 2 to 80 nm), prepared with a liquid metal ion source, were analysed in a scanning transmission electron microscope (STEM) by electron energy loss spectroscopy (EELS). Both volume and surface plasmon excitations were investigated and their dependence on the cluster size interpreted by classical and quantum mechanical models. A blue shift of the volume plasmon energy with decreasing radius R of the cluster was clearly detected. The full width at half maximum (FWHM) of the peak, related to the damping of the volume plasmon excitation, showed a dependence in 1/R. …

Opportunities For Electron Microscopy In Space Radiation Biology, J. T. Lett

Scanning Electron Microscopy

Densely ionizing, particulate radiations in outer space are likely to cause to mammalian tissues biological damage that is particularly amenable to examination by the techniques of electron microscopy. This situation arises primarily from the fact that once the density of ionization along the particle track exceeds a certain value, small discrete lesions involving many adjacent cells may be caused in organized tissues. Tissue damage produced by ionization densities below the critical value also afford opportunities for electron microscopic evaluation, as is shown by the damage produced in optic and proximate tissues of the New Zealand white rabbit in terrestrial experiments. …

An Organic Reference Specimen: Polyacrylonitrile Film Deposited On Oxidizable Metals By Electro-Polymerization, C. Boiziau, G. Lécayon

Scanning Electron Microscopy

Surface investigations of organic materials require the provision of reference specimens for calibrating experimental equipment.

Because of their specific properties (purity, reproducibility, well-known molecular structure and orderly inter-molecular structure, electronic properties associating conductive and insulating behaviour, quality of the film-to-metal bound), polyacrylonitrile films obtained through electro-polymerization on oxidizable metal cathodes (Fe, Ni, Cu) may be used as a first type of reference sample.

Experimental results, obtained by various surface investigation techniques are presented, and their validity evaluated.

Cathodoluminescence Study Of Defects In Iii-V Substrates And Structures, M. Cocito, P. Franzosi, G. Salviati, F. Taiariol

Scanning Electron Microscopy

Solid state detector cathodoluminescence studies of semiconducting and semi-insulating GaAs and InP crystals, were performed. The origin of the dislocation contrast in GaAs:Si doped substrates, in the carrier concentration range from 10¹⁶ to 6 · 10¹⁸ cm^-3, were discussed. The image contrast was explained on the basis of the emission efficiency versus carrier concentration curve, obtained in the transmission mode. Single dislocations and dislocation arrangements in addition to growth striations, clusters and precipitate-like microdefects were evidenced. The above mentioned microdefects were detected in GaAs: Te, S and Si doped and InP: Sn doped specimens. Commercial InP:Sn …

A High Efficiency Cathodoluminescence System And Its Application To Optical Materials, A. D. Trigg

Scanning Electron Microscopy

A high collection efficiency spectroscopic cathodoluminescence (CL) system based on an in-line ellipsoidal mirror has been constructed for use on a Cambridge S250 scanning electron microscope (SEM). It can be fitted to or removed from the SEM in about 30 minutes and requires no significant modification of the instrument. It can be used to obtain total CL images, monochromatic CL images or CL spectra with an ultimate spectral resolution of 1 nm.

The system has been applied to the study of doped synthetic quartz crystals, optical fibres and optical fibre preforms, and to yttrium aluminium garnet, bismuth silicon oxide and …

Fundamental Aspects Of Energetic Particle/Solid Interactions, Nicholas Winograd

Scanning Electron Microscopy

The interaction of keV particles with solids has been characterized by the measurement of the angle and energy distribution of sputtered secondary ions and neutrals. The results are compared to classical dynamics calculations of the ion impact event. Examples using secondary ions are given for clean Ni{001}, Cu{001} reacted with O₂, Ni{001} and Ni{7 9 11) reacted with CO, and Ag{111} reacted with benzene. The neutral Rh atoms desorbed from Rh{001} are characterized by multiphoton resonance ionizaton of these atoms after they have left the surface.

The Cathodoluminescence Mode Of The Scanning Electron Microscope: A Powerful Microcharacterization Technique, D. B. Holt, F. M. Saba

Scanning Electron Microscopy

By detecting cathodoluminescence (CL) in a scanning electron microscope (SEM), pan and monochromatic micrographs and CL spectral analyses analogous to x-ray mode point analyses can be obtained. Complete microcharacterization requires alternate examination of both micrographs and spectra. New techniques for near infra-red CL and low-temperatures to produce sharp spectra are of increasing importance. CL emission is due to electron transitions between quantum mechanical states so the radiative defects present can be unambiguously identified at liquid helium temperatures. Strongly luminescent impurities can be detected to below one part in 10⁸. This is 10⁴ times as sensitive as the …

Liquid Metal Sources In Ion Microscopy And Secondary Ion Mass Spectrometry, G. L. R. Mair, T. Mulvey

Scanning Electron Microscopy

This paper reports on state-of-the-art developments in liquid metal sources and some of the finer points of their operating characteristics that are especially relevant to the satisfactory functioning of analytical ion scanning microscopes equipped with secondary ion mass spectrometers. Such effects include unwanted emissions from the source and their exclusion by means of filters and mass separators in the ion-optical column. The design of the ion-optical column is also discussed and some applications of this rapidly advancing form of analytical microscopy are described.

Secondary Ion Mass Spectrometry Of Glasses: Aspects Of Quantification, H. Odelius, A. R. E. Lodding, L. O. Werme, D. E. Clark

Scanning Electron Microscopy

SIMS routines have been developed for the analysis of oxide materials, with applications particularly in element profiling of corrosion layers on glasses after weathering or leaching. The possibilities of quantification and reproducibility have been found critically sensitive to the buildup of charge on the insulating specimens. With control of constant specimen potential, relative sensitivity factors in the positive mass spectrum have been determined for about 20 elements in 10 different alkali-borosilicate glasses. Secondary ion yields were studied as functions of the energy range of ions admitted to the analyzer. At relatively low energies, including the top of the energy distribution, …

A New Approach For Studying Semithin Sections Of Human Pathological Material: Intermicroscopic Correlation Between Light Microscopy And Scanning Electron Microscopy, G. Pasquinelli, C. Scala, G. P. Borsetti, F. Martegani, R. Laschi

Scanning Electron Microscopy

In order to obtain useful and complete information on the study of pathological material, we observed by scanning electron microscopy (SEM) the same semithin sections observed by light microscopy (LM). For this purpose, the specimen must have, at the same time, chromatic and electron dense characteristics.

We thus developed different specimen preparation methods, subjecting the semithin sections to specific polychromatic staining with high atomic number (Z) elements, to monochromatic staining followed by routine contrasting with uranyl acetate and lead citrate, and to specific cytochemical and immunocytochemical procedures.

The specimens were examined in sequence by LM, by SEM equipped with secondary …

Contribution Of Scanning Electron Microscopy And Associated Analytical Techniques To The Study Of Atherosclerotic Disease, R. Laschi

Scanning Electron Microscopy

Human carotid atheroma has been examined by scanning electron microscopy (SEM) utilizing both secondary and backscattered electron detectors and transmission electron microscopy (TEM) both at conventional and high voltage.

Different cytochemical techniques have been used to map elastic fibers, proteoglycans, calcium, non esterified cholesterol. By immunocytochemistry the distribution of factor VIII related antigen and actin has been studied.

With SEM it was possible to detect aspects of carotid plaques not appreciated when using other conventional techniques. With TEM some modifications of the structural and/or functional features of connective tissue macromolecules have been observed. The occurrence of anomalous collagen has been …

Clinical Applications Of Scanning Electron Microscopy In Gastrointestinal Diseases, F. Bonvicini, G. Zoli, M. C. Maltarello, D. Bianchi, G. Pasquinelli, P. Versura, G. Gasbarrini, R. Laschi

Scanning Electron Microscopy

We considered the role of scanning electron microscopy (SEM) in clinical investigation of different gastrointestinal diseases. The following clinical applications of SEM may be suggested on the basis of our original data and those reported in literature:

in peptic ulcer: assessment of the completeness of healing, by observing the mucosal surface architecture of the scars; identification of mucosal changes, namely enterocytic surface membrane alterations, predictive of recurrence;

in coeliac disease: early assessment of the response to gluten-free diet and follow-up of the patients by staging the process of mucosal repair in cerebriform, intermediate and villous patterns;

in ulcerative …

Scanning Electron Microscopy Of The Human Myocardium, S. Siew

Scanning Electron Microscopy

Owing to the impossibility of fixation, in the human being, by means of perfusion in vivo and the rare availability of fresh comparatively intact hearts resected at transplantation, the possibility was explored of using post-mortem material in instances where the autopsies were performed within 2 hours of demise of the patients. Four cases were examined: 2 normal adult hearts and 2 hearts of hypertensive patients in the stage of decompensation. The hearts were fixed by means of perfusion with 2.5% glutaraldehyde in phosphate buffer, pH 7.4. Contiguous blocks were taken for light microscopy (LM) and scanning electron microscopy (SEM) from …

Scanning And Transmission Electron Microscopy Of Bacterial Attachment To Mucosal Surfaces With Particular Reference To The Human Fallopian Tube, Morris D. Cooper, Christine Jeffery

Scanning Electron Microscopy

Neisseria gonorrhoeae and Chlamydia trachomatis are the common bacteria isolated from bacterial cervicitis and are the leading etiological agents for pelvic inflammatory disease. Neisseria gonorrhoeae cause infection of the mucosa of fallopian tubes in organ culture by (a) attaching to microvilli of nonciliated cells, (b) phagocytosis by these cells, (c) transport across and exocytosis from the epithelial cells. In contrast the Chlamydia attach to the epithelial surface without apparent ligand binding and are taken into the cytoplasm of the epithelial cell. Exocytosis of Chlamydia is into the tubal lumen and not into the subepithelial spaces. The ciliated epithelial cells of …

Characteristic Energy Losses With High Energy Electrons Up To 2.5 Mev, B. Jouffrey, J. Sevely, G. Zanchi, Y. Kihn

Scanning Electron Microscopy

Some aspects of the influence of the energy of the incident electrons in electron energy loss spectroscopy (EELS) are considered. It is shown that this method of analysis used in high voltage electron microscopy, permits one to observe, with a better edge jump ratio than at lower accelerating voltages, the characteristic edges. One important question is to eliminate artefacts in the counting and to record only electrons from the true spectrum. Some recent examples are given. One of them concerns extended energy loss fine structures (EXELFS). It seems high voltage electron microscopy (HVEM) could be very useful in this domain.

Morphological Observations Of Mineralizing Pericardium Cardiac Grafts, P. Frasca, J. W. Buchanan, R. Z. Soriano, J. M. Dunn, L. Marmon, J. Melbin, S. J. Buchanan, E. E. Golub, I. M. Shapiro

Scanning Electron Microscopy

Pericardial patch grafts were implanted in the hearts of young sheep for periods ranging from two to 120 days. Explants seven to 21 days old revealed the formation of a "pseudoneointima" (PNI) on the blood contacting surface of the pericardium. The PNI was more heavily mineralized than the pericardium. Mineralization was most intense on the blood contacting surface of the PNI and on the chamber surface of the pericardium. After three weeks of implantation, the PNI was much thinner and was organized into a thin fibrous capsule without any signs of mineralization. In the pericardium, mineral deposits were seen in …

Scanning Electron Microscopy Studies Of Staphylococcal Adherence To Heart Valve Endothelial Cells In Organ Culture: An In Vitro Model Of Acute Endocarditis, Morris D. Cooper, Christine Jeffery, Debra L. Gall, Andrew S. Anderson

Scanning Electron Microscopy

Organ cultures of human heart valves were used as a model to study the initial pathobiology of acute infective bacterial endocarditis. We used Staphylococcus aureus isolated from a case of infective endocarditis to infect the in vitro culture of the heart valves. Using scanning electron microscopy, we assessed the initial damage, attachment to and invasion of the endothelial cell layer by staphylococci. Our results indicate there is initial damage to the endothelium prior to observation of staphylococci attaching to the endothelial cell. By 12 h post infection, there is significant attachment and damage. At 24 h after infection, destruction of …

Quantitation Of Scanning Electron Microscopic Urinary Cytology, M. Cano, R. B. Wilson, S. M. Cohen

Scanning Electron Microscopy

Using scanning electron microscopy (SEM), differences in cell surface morphology are identifiable between normal urothelium and malignant urothelia including the presence of pleomorphic microvilli (PMV). PMV have been reported in carcinomas of the urinary bladder, and they appear early in the pathogenesis of these tumors in animal models. Preliminary studies in our laboratory and others' demonstrated similar changes in tissue and cytologic specimens from patients with bladder cancer. We observed and evaluated normal and neoplastic cells of the human bladder by SEM in a preliminary assessment of surface topography with regard to tumor growth, grade, and stage. However, while these …

Simulation With Pharmacological Agents Of Radiation Damage To Small Intestinal Villi, M. Indran, F. C. Boyle, K. E. Carr

Scanning Electron Microscopy

Irradiation induces damage to intestinal villi, resulting in a progressive decline in villous height and changes in topography. Gamma and neutron radiation are reported to cause changes in the structure of smooth muscle and nerve twigs of the intestinal wall. It is possible, therefore, that villous collapse may be due partly to changes in the underlying stromal elements as a result of damage to nerve or muscle.

To test this hypothesis, mice were treated with the drug reserpine which is known to affect the neural control of intestinal smooth muscle function and the small intestine was examined for topographical and …

Stroboscopic Technique For Dynamic Observation Of Ferromagnetic Domains At Low Frequencies In Scanning Electron Microscopy, T. Ikuta

Scanning Electron Microscopy

A new stroboscopic technique for the observation of periodic phenomena at low frequencies (10 -100 Hz) in scanning electron microscopy (SEM) is developed in the present study. This new technique is based on the line-sampling stroboscopy instead of the point-sampling stroboscopy which has been commonly used for the dynamic observation at high frequencies (> 1 kHz). In this stroboscopy, a multi-frame display with the individual stroboscopic image at different phase can be easily introduced with no reduction of the detection efficiency.

The main application of the present stroboscopy at low frequencies is the dynamic observation of magnetic domains. In this …

A Dynamic Single E-Beam Short/Open Testing Technique, M. Brunner, B. Lischke

Scanning Electron Microscopy

Several electron beam techniques for electrical testing of interconnection modules have been presented by different authors in recent years. Most techniques use two or more electron beam energies to establish a charging and a non-loading reading mode. The present paper discusses the feasibility of employing the same beam energy for charging contact pads and reading pad potentials. This avoids the necessity of high voltage switching as used for altering the beam energy. A switching time of 100 us between 2 kV and 4 kV beam voltage which is restricted to this range has been reported earlier. Without switching, higher beam …

Interactions Between Spermatozoa And The Crypts, Cilia, And Mucus Of The Cervix In The Ewe, William P. Wergin

Scanning Electron Microscopy

In ruminants, minor cervical folds, commonly called crypts, temporarily store spermatozoa for a short interval of time between insemination and fertilization. However, the mechanism by which spermatozoa are transported to these crypts and subsequently to the uterus is not known. To study this problem, cervical tissue, which was removed from ewes that were naturally inseminated by rams at estrus, was examined with the scanning electron microscope to determine the physical associations that occur between the spermatozoa and the structural features of the cervix. The study indicates that the spermatozoa generally are not oriented parallel to the longitudinal axis of the …

The Effect Of High Energy (Hze) Particle Radiation (40ar) On Aging Parameters Of Mouse Hippocampus And Retina, D. E. Philpott, W. Sapp, J. Miquel, K. Kato, R. Corbett, J. Stevenson, S. Black, K. A. Lindseth, E. V. Benton

Scanning Electron Microscopy

Eight month old C57BL6 mice were exposed (head only) to 0.5 rad or 50 rads of Argon particles at the Lawrence Berkeley Radiation Facility, CA. Neuromotor performance was assessed monthly for six months beginning twelve weeks post-irradiation using a ''string test". The decline in motor performance was dose-related and none of the animals was able to complete the task after four months of testing. Morphological changes were monitored six and twelve months post-irradiation by light and electron microscopy. The synaptic density in the CA-1 area of the hippocampus decreased six and twelve months after irradiation. The decrease after twelve months …

The Influence Of Epidermal Growth Factor On Surface Morphology Of Fetal Rat Hepatocytes In Primary Culture, Ira H. Ames, Robert A. Richman, Gerald B. Gordon, Barbara A. Toly, Mark R. Benedict, Maureen A. Barcza

Scanning Electron Microscopy

In an attempt to understand the hormonal regulation of somatomedin secretion in the fetus, we have confirmed that epidermal growth factor (EGF) stimulates fetal rat hepatocytes in primary culture to secrete somatomedin in a time and a dose-dependent fashion. Transmission electron microscopy (TEM) revealed that the cultured cells had ultrastructural features consistent with those of fetal hepatocytes. Scanning electron microscopy (SEM) showed that cells grown in either Medium 199 or EGF supplemented Medium 199 formed cellular aggregates within 6 h. The surface features of cells in control and experimental cultures were indistinguishable up until 24 h after exposure to EGF. …

Two Quantum Photoemission In Semiconductors, J. M. Moison, M. Bensoussan

Scanning Electron Microscopy

Two-quantum photoemission is a process in which two times the photon energy is transferred to the photoelectron. In this process, the photoelectron observed in the vacuum keeps a "memory" of the intermediate empty state by which it transited after its first excitation, and before its second excitation and its final escape. We discuss here the experimental problems involved and the information obtained in the case of the semiconductors Si and InP. We show that ballistic or non-ballistic electrons can be selected by an adequate choice of experimental conditions, yielding information on both the static and dynamic properties of the empty …

The Electron Microscope Detection And X-Ray Quantitation Of Cations In Bacterial Cells, D. C. Sigee, M. H. El-Masry, R. H. Al-Rabaee

Scanning Electron Microscopy

Electron microscope autoradiography and X-ray microanalysis have been used for the detection and quantitation of cations in the bacterium Pseudomonas tabaci. These techniques differ in the information they provide (relating to either cation uptake or in situ levels), their applicability to different cations, their sensitivity and their spatial resolution. With uptake of ⁶³Ni²⁺, high resolution autoradiography (involving gold latensification and physical development) demonstrated a high degree of cation localisation to the central nucleoid area (glutaraldehyde-fixed cells) and within this to the constituent chromatin (acetic-alcohol preparations).

X-ray microanalysis of whole bacterial cells revealed the presence of substantial levels …

Scanning Acoustic Microscopy In Materials Characterization, H. R. Vetters, P. Mayr, S. Boseck, Th. Luebben, R. Matthaei, A. Schulz

Scanning Electron Microscopy

The scanning acoustic microscopy is a powerful tool for subsurface imaging and therefore fault detection in coated parts. In this paper several methods are established to reveal the imaging of hidden structures. First efforts were made to find out the information depth due to the various distances between lens and surface of the object. By means of a specially developed test specimen it was possible to estimate the penetration depth for monitoring structural details. The indepth analysis of layered composites is considered by the determination of the V(z)-characteristics. Furthermore the gain of image processing by means of Fourier transformed patterns …

Use Of Polymer Casts Or Metal Particle Infusion Of Ducts To Study Antigen Uptake In The Guinea Pig Mammary Gland, D. I. Schenkman, D. T. Berman, R. M. Albrecht

Scanning Electron Microscopy

Microcorrosion casts were made of the duct system of guinea pig mammary glands by intramammary infusion of Mercox® polyester resin following involution of the glands after the first lactation. The acinar configuration of the involuted gland was apparent on examination of the casts by scanning electron microscopy (SEM). Surface features, which were readily identified as those of imprints of duct al epithelium, were visible at higher magnifications. The morphology of these casts corresponded to the patterns observed by SEM of ethanol cryofractured specimens of mammary tissue.

Cryofractured specimens of guinea pig mammary glands were also examined by SEM following intramammary …