Biology Commons^™

Simultaneous Micro-Characterization Of The Superconducting And Structural Properties Of High-Tc Superconducting Films, R. P. Huebener, R. Gross

Scanning Microscopy

Important information on the local values of the critical temperature and the critical current density in high-T_c superconducting films is obtained by low-temperature scanning electron microscopy (LTSEM). The imaging principle of LTSEM is based on the local beam-induced heating effect and the detection of a voltage response signal in the current-biased specimen film. During the scanning process the sample is mounted on a low-temperature stage the temperature of which is electronically stabilized at some specific value in the range of interest. The local superconducting quantities measured by LTSEM can be correlated with the microstructure of the specimen film investigated …

Microscopy Analysis Of Dental Titanium Casting Investment Materials, H. J. Mueller

Scanning Microscopy

Scanning electron microscopy (SEM) analysis and qualitative energy dispersive x-ray microanalysis (EDS) of investment materials for dental titanium casting were performed. Two commercial investment materials, Ohara and Castmatic, and an experimental zirconia material were analyzed. The microstructural constituents and the unfired and fired structures were included. Larger refractory particles and matrix embedding smaller particles were observed with each material. Detection of aluminum, silicon, magnesium, zirconium and oxygen provided a basis to reason the presence of alumina (Al₂O₃), silica (SiO₂), magnesia (MgO), and zirconia (ZrO₂). Hence, Ohara contained quartz and an alumino-silicate, Castmatic …

Scanning Electron Microscopy Of Lung Following Alpha Irradiation, C. L. Sanders, K. E. Lauhala, K. E. Mcdonald

Scanning Microscopy

Pulmonary aggregation of inhaled ²³⁹PuO₂ particles leads to a cellular evolution of focal inflammation, fibrosis, epithelial dysplasia and lung tumor formation. Female Wistar rats were exposed to an aerosol of high-fired ²³⁹PuO₂ (initial lung burden, 3.9 kBq) and the lungs examined at intervals from 1 day to 700 days after exposure by light and scanning electron microscopy and autoradiography. Peribronchiolar Pu particle aggregation increased with time, resulting in well-defined focal inflammatory lesions after 120 days and fibrotic lesions after 180 days. A generalized hypertrophy and hyperplasia of nonciliated bronchiolar cells was seen at 15 days and …

Biuret Staining And X-Ray Microanalysis For Locating Grafted Poly(Methyl Acrylate) On Wool Fibers, R. R. Bresee, P. A. Annis

Scanning Microscopy

Biuret reagent was used to stain wool fibers with copper so the location of a small amount of poly(methyl acrylate) grafted onto the fibers could be determined by energy dispersive x-ray microanalysis of copper. The grafted polymer was determined to be located in regions of the fibers where cuticle had been previously damaged. The amount of grafted polymer present was too small for secondary electron imaging to be useful for locating the polymer grafts.

Dendritic Oxide Growth On The Surface Of Liquid Gallium, Y. L. Wang, A. Raval, R. Levi-Setti

Scanning Microscopy

We have studied the oxidation of a liquid gallium surface with a high spatial resolution scanning ion microprobe. A 40 keV focused gallium ion beam, extracted from a liquid metal ion source, was employed, first, to sputter clean a 40 x 40 μm² area on a drop of liquid gallium, in a ultra high vacuum (UHV) specimen chamber. It was then used to monitor the oxide growth by secondary ion mass spectrometry imaging microanalysis while the chamber was gradually back-filled with oxygen. In the initial stages, gallium oxide grew in a dendritic pattern from the edge of the cleaned …

Surface And Grain Boundary Analysis Of High Temperature Superconductors, F. J. Himpsel, A. G. Schrott

Scanning Microscopy

The purpose of this paper is to survey the methods that are available for probing surfaces and grain boundaries of high temperature superconductors. Various surface-sensitive spectroscopies are applied to the analysis of YBa₂Cu₃O_7-x and Bi₂Sr₂CaCu₂O_8+x including photoelectron spectroscopy, spatially-resolved electron energy loss spectroscopy, and scanning electron microscopy (SEM). One of the major sources of contamination at surfaces and grain boundaries is found to be BaCO₃. The cleavage surface of single crystal Bi₂Sr₂CaCu₂O_8+x is inert and can be used to …

A Calculation Method Of X-Ray Emitted Intensity In Multi-Layer Films By Monte Carlo Simulation, Yen-Cai Ho, Jia-Guang Chen, Xin-Lei Wang

Scanning Microscopy

A calculation method of X-ray emitted intensity in multi-layer films is proposed in this paper. The method is based on the work developed by us: (1) a simplified physical model of electron scattering and Monte Carlo evaluations in a single medium and in multi-layer media and (2) the theories and the formulae for excitation, absorption and fluorescence of characteristic X-rays. The intensity ratio of X-rays for the known thickness films, Au/Cu/Si and Cr/Ni/Si, were calculated at 20, 25 and 30 keV. Calculated results are compared with experimental values of electron microprobe analysis for the multi-layer film specimens, and the correspondence …

The Dark Side Of Bright Metal Coatings, L. Bartosiewicz, C. J. Kelly

Scanning Microscopy

The surface quality of light reflective metal films on polymer substrates were experimentally examined and evaluated. The study included light optical hotstage microscopy of in-situ samples and scanning electron microscopy. Conditions for producing aluminum metal films with desirable light reflecting properties are relatively demanding. The film formation is a complex series of events which include nucleation, coalescence and crystal growth.

Surface flaws, debris or other imperfections are readily visualized with the aid of the optical or the electron microscope. Although complex methods have been developed for the examination of small surface areas with fine-featured metallic films, there was little incentive …

Endothelial Injury In Human Atherosclerosis, G. Pasquinelli, A. Cavazza, P. Preda, A. Stella, B. I. Cifiello, M. Gargiulo, M. D'Addato, R. Laschi

Scanning Microscopy

A light and electron microscopic investigation (scanning and transmission electron microscopy) was performed on 51 human atherosclerotic carotid lesions. The purpose of this study was to establish whether features of endothelial injury such as those described in animals occur in man and whether these features can be related to specific stages of human atherosclerosis.

Irrespective of their histological appearance the atherosclerotic lesions were covered with endothelium which showed non-specific changes in cell shape and size. However, all complicated lesions appeared denuded. Moreover, a peculiar interaction of endothelium with monocytes and lymphocytes as well as blood components (e.g., fibrin and lipoproteins) …

A Contribution To The Scanning Electron Microscope Based Microcharacterization Of Semi-Insulating Gallium Arsenide Substrates, D. Köhler, G. Koschek, E. Kubalek

Scanning Microscopy

The macroscopic behaviour of semiconducting materials is determined by the distribution of microscopic defects like dislocations, impurities and intrinsic defects. Therefore, microanalytical methods are necessary to control the influence of technological process parameters on the materials properties. In the case of GaAs substrates, measurements of the cathodoluminescence (CL) and the electron beam induced voltage (EBIV) as well as the new charging technique seem to be promising methods to perform this task. CL-micrographs of as-grown GaAs substrates show bright cellular structures, which correspond to dislocation networks. Comparative investigations by use of the new charging contrast technique indicate an increased conductivity in …

Recent Uses Of Electron Microscopy In The Study Of Physico-Chemical Processes Affecting The Reactivity Of Synthetic And Biological Apatites, J. D. B. Featherstone, D. G. A. Nelson

Scanning Microscopy

Studies which used scanning electron microscopy (SEM) to investigate subsurface demineralization of dental enamel have recently been well reviewed. The purpose of the present paper was to review several studies, carried out in our laboratories, which have used electron microscopy to examine physicochemical properties of synthetic and biological apatites, to relate these results to previous studies, and to present new data.

Aspects of the ultrastructure of hydroxyapatite and carbonated-apatites have been observed by high resolution transmission electron microscopy, and related to shape and growth of these crystals.

Surface morphologies of discs prepared from precipitated carbonated-apatites and from ceramic carbonated-apatites were …

Immunological Characterization Of An Sds/Kcl Isolated Total Protein Antigen Of Bluetongue Virus Serotype 13, Vicki L. Shore

Undergraduate Honors Capstone Projects

Because of the damaging effects of bluetongue disease on the livestock industry, interest exists in developing a means of inducing passive immunity in infected animals. Antibodies against VP2, the polypeptide responsible for immunoantigenicity in bluetongue virus (BTV), have been found to elicit neutralizing antibodies; however, production of this purified antigen is very costly and thus impractical for commercial purposes. Total viral protein, prepared by a simple, rapid, highly reproducible SDS/KCl method, was injected into rabbits and found to produce antibodies which are useful in immunoblots. However, plaque neutralization assays failed to detect any neutralization activity by these antibodies. Denaturation of …

Characterization Of Anti-Pichinde Virus Monoclonal Antibodies For The Directed Delivery Of Antiviral Drugs And Toxins, Noah Jefferson Burns Iii

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Mouse monoclonal antibodies directed against Pichinde virus (PCV) were produced to evaluate their application as vehicles for the delivery of antiviral drugs or toxins to virus-infected cells. Four monoclonal antibodies, PC4.9A6, PC4.9D3, PC4.7C2, and PC4.8D3, were of the IgG2a subisotype and reacted with acetone-fixed and live PCV-infected Vero-76 cells. In vivo stained splenic macrophages derived from PCV-infected hamsters that had been injected with fluorescein-labeled PC4.9A6 (FITC9A6) demonstrated a 400% increase in total fluorescence over similarly treated, non-infected cells when analyzed by flow cytometry. This is an indication that FITC-9A6 does have some ability to specifically target PCV infected cells in …

In Vitro Identification Of The Effect Of Serotonin On Lymphocyte Dna Synthesis And Natural Killer Cell Activity, Kim Kartchener Kane

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to identify the effects of the neurotransmitter, serotonin (SE), on the immune function of peripheral blood mononuclear cells (PBMC) of normal, healthy subjects. This was done as a preliminary investigation to studies on the association of SE with immune changes in autistic subjects.

The PBMC isolated from normal male subjects were treated with various concentrations of SE for 48 hrs. Their incubation in SE at a concentration of 10^-3 M induced about a 35% decrease in DNA synthesis. However, incubation of the cells in lower concentrations (10^-4 to 10^-10) of …

Effects Of Methylene Chloride On Immune Function In Mice And The In Vitro Effect Of Methylene Chloride In Immunologic Assays, Man-Ping Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A number of toxicities associated with methylene chloride have been found in both human subjects and mice. However, relatively few studies have probed immunotoxicities of methylene chloride. In order to examine possible immunotoxicities or immunomodulating effects of methylene chloride, several tests of cellular immune function were performed using both human in in vitro studies and a mouse model.

Body weights and specific organ weights of thymus, spleen, liver, and kidney were normal in CD-1 mice given various concentrations of methylenechloride. However, a significantly reduced mitogenic response to phytohemagglutinin (PHA} and reduced interleukin-2 (IL-2} production was found in these methylene-chloride-treated mice. …

Purification And Characterization Of A Chemically Induced Epstein-Barr Virus-Associated Deoxyribonuclease, Guang-Yuh Hwang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Purification of Epstein-Barr virus-associated deoxyribonuclease (EBV-DNase) from Raji and P₃HR-1 cells treated with 12-0-tetradecanoylphorbol-13-acetate and sodium butyrate was performed by sequential ion-exchange column chromatography and fast protein liquid chromatography. The enzyme activity, protein concentration, yield, specific activity, purification profiles, and polypeptide patterns by electrophoretic analysis in each column purification step were determined. The characteristics of the partially isolated EBV-DNase were demonstrated by the enzyme activity, DNA binding affinity, and inhibition by the nasopharyngeal carcinoma patient sera and rabbit polyclonal antibodies against the partially purified EBV-DNase. A nonisotopic assay was developed as a new method in detecting the nuclease. …

Olfactory And Nasal Respiratory Epithelia, And Foliate Taste Buds Visualized With Rapid-Freeze Freeze-Substitution And Lowicryl K11m Embedding. Ultrastructural And Initial Cytochemical Studies., Bert Ph. M. Menco

Scanning Microscopy

Rat olfactory and respiratory epithelia and Rhesus monkey taste buds were studied with rapid-freeze, acetone/0.1% uranyl acetate freeze-substitution and low-temperature Lowicryl K11M embedding, usually in the absence of other chemical fixation and cryoprotection procedures. Ultrastructural features of mucus, cytoplasm, including cytoskeletons, and membranes were better retained than with conventional methods. Some major examples: The mucus of the olfactory epithelium consisted of a single layer; that of the respiratory epithelium had an electron-opaque sol layer surrounding cilia and microvilli below a thin laminated electron-lucent gel layer. Taste-bud pores displayed a foam-like opaque secretory product, resembling the contents of secretory granules within …

Solution-Mediated Transformation Of Octacalcium Phosphate (Ocp) To Apatite, R. Z. Legeros, G. Daculsi, I. Orly, T. Abergas, W. Torres

Scanning Microscopy

OCP crystals were hydrolyzed in solutions containing Ca²⁺, Mg²⁺, HPO₄^2-, CO₃^2-, F^-, citrate or P₂O₇ ions. Products of hydrolysis were analyzed using scanning (SEM) and transmission (TEM) electron microscopy, infrared spectroscopy and x-ray diffraction.

Results demonstrated that the OCP to Apatite (AP) transformation is influenced by: (1) types of ions in solution: inhibited by Mg²⁺, citrate or P₂O₇^4-; facilitated by F^-, CO₃^2-, HPO₄^2- or Ca²⁺ ions; (2) ionic concentrations; (3) …

Microbiological Immunocytochemistry: A Review Of Current Trends And Applications, Julian E. Beesley

Scanning Microscopy

It has been considered worthwhile to update previous reviews of microbiological immunocytochemistry in order to identify areas of current importance in this continually expanding area of research. Publications in virology, bacteriology and protozoology indicate a continued interest in immunocytochemistry. Deployment of colloidal gold techniques is almost universal in these applications. The post-embedding technique was the most widely applied technique although a few studies employed the immunonegative stain, pre-embedding and immunoreplica techniques, thereby reflecting the use of colloidal gold in all other areas of the biological sciences.

The Vascularization Of The Skin Of The Atlantic Hagfish, Myxine Glutinosa L. As Revealed By Scanning Electron Microscopy Of Vascular Corrosion Casts, A. Lametschwandtner, T. Weiger, U. Lametschwandtner, V. Georgieva-Hanson, R. A. Patzner, H. Adam

Scanning Microscopy

The vascularization of three different (A, B, C) skin regions (from the level of the heart to the cloaca including dorsal, lateral and ventral skin areas) of the Atlantic hagfish, Myxine glutinosa L. was studied by scanning electron microscopy of vascular corrosion casts. Vessel variables were measured either from semithin sections (diameters) or from vascular corrosion casts (diameters, lengths) and total blood capacities as well as vessel surfaces per unit skin area (mm²) were calculated. There are no significant differences in the number of subepidermal capillary meshes (ranging from 164 to 185 meshes per micrograph) in areas A, …

Interpretation Of Structural Patterns Appearing On Corrosion Casts Of Small Blood And Initial Lymphatic Vessels, A. Castenholz

Scanning Microscopy

Structures imprinted on the corrosion casts of blood and lymphatic microvessels are examined by correlative scanning electron microscopy of corroded casts and fixed tissue. Replicas of the endothelial nuclear portions and cell boundaries and the plastic bands surrounding the casts of terminal blood vessels are demonstrated. In small lymphatics the replication of valve structures, interendothelial open junctions and direct prelymphatic connections is shown. The different imprint patterns are examined in regard to their morphological significance and under methodical aspects.

Ranking Corrosion Efficiency: A Latin Square Study On Rat Lung Microvascular Corrosion Casts, Dean E. Schraufnagel

Scanning Microscopy

Scanning electron microscopy of corrosion casts is an important tool for the study of microvascular structure but few systematic studies on methods of specimen preparation have been reported. This study sought to determine the relative importance of factors involved in corrosion. It compared potassium hydroxide, sodium hydroxide and water as major corrosive agents. It tested the size of the tissue sample, and the use of prealkali autolysis, detergent, and proteolytic enzymes in a Latin square designed study. The main findings were that sodium and potassium hydroxide were better than water (P < 0.0001) and the longer the corrosion time the better corroded the samples were (P < 0.0001 ). Although not a controlled factor, higher room temperature was also associated with better corrosion. The use of proteolytic enzymes, detergent, and warm tap water alone before the alkali treatment did not significantly improve the corrosion in this study, although this does not preclude an effect with another experimental design.

Scanning Near Field Optical Microscopy (Snom) In Reflection Or Scanning Optical Tunneling Microscopy (Sotm), U. Ch. Fischer, U. T. Dürig, D. W. Pohl

Scanning Microscopy

The recent exploitation of near field optics opened a new branch of light microscopy beyond the diffraction limit. With scanning near field optical microscopy a lateral resolution of 20 and 50 nm was obtained in transmission and reflection, respectively. In a novel optical tunneling mode, also the topography of pure phase objects has been imaged at a resolution of 50 nm laterally and 1 nm vertically.

Modular Detector System For Scanning Transmission Electron Microscope, A. V. Jones, M. Haider

Scanning Microscopy

This paper describes a multiple detector system based on a high-dispersion highly-corrected spectrometer close-coupled to a high-excitation objective lens. The design enables all post-specimen detectors (including the elastic dark-field detector) to be transferred to the post-spectrometer region.

This in turn makes possible the simultaneous acquisition of filtered bright-field, elastic dark-field and inelastic images.

The associated data acquisition system has provision for up to four simultaneous inputs and is based on a 32-bit microprocessor with 2 Mbytes of memory and 85 Mbytes of local disk storage. Images can be archived locally (cassette tape) or transferred via Ethernet to the laboratory central …

Determination Of Protein, R. Reichelt, A. Engel

Scanning Microscopy

Elastic and inelastic dark-field micrographs simultaneously recorded by the scanning transmission electron microscope (STEM) provide structural and quantitative chemical information at a spatial resolution of some nanometers. Simultaneous acquisition is essential as it warrants: (i) the geometrical identity of picture elements (pixels) in these micrographs, and (ii) the identity of recording conditions (focus, electron dose) for the elastic and inelastic images. Suitable off-line processing of such multichannel images allows the concentration of protein or nucleic acid within embedding material to be evaluated. In addition, location and number of chemical elements such as phosphorus can be determined. Theoretical sensitivity is a …

Scanning Electron Microscopy In The Study Of Campylobacter Pylori Associated Gastritis, F. Bonvicini, P. Versura, S. Pretolani, G. Gasbarrini, R. Laschi

Scanning Microscopy

The close association between Campylobacter pylori (CP), gastritis and peptic ulcer is now well established. Moreover increasing evidence has been collected of a major etiological role of CP in type B chronic gastritis. For this reason, searching for CP is essential in all patients with upper gastrointestinal symptoms.

Scanning electron microscopy (SEM) is a most reliable technique for studying the distribution of microorganisms and their relationship to the gastric mucosal surface.

The aim of this paper is to compare SEM to other routine methods of detection for CP, such as Giemsa staining on histological sections and Urease Microtiter Test (MT) …

Scanning Electron Microscopy Of Chondritic Meteorites: Evidence For Condensation And Aggregation Processes During The Birth Of The Solar System, Glenn J. Macpherson, Jeffrey N. Grossman

Scanning Microscopy

Carbonaceous chondrite meteorites preserve evidence of how the solar system formed and evolved through its earliest stages. Extracting these clues from small and very fine grained (a few tens of μm and smaller in many cases) meteorite components has required extensive use of micro beam techniques-scanning electron microscopy (SEM), electron and ion microprobe. Correlated studies have allowed textural, major and trace element and isotopic data to be gathered on the same precious microsamples. The best method for examining textures in these meteorites is scanning electron microscopy of flat polished sections using compositional back-scattered electron imaging.

X-Ray Microanalysis Of Mammalian Salivary Glands, Godfried M. Roomans, R. Margareta Müller, Samuel Sagström, Gun-Britt Sagulin, Susan M. Scarlett, Joanna Wroblewski, Maria Albertsson

Scanning Microscopy

X-ray microanalysis was used to study the elemental composition of major salivary glands in rat and man. The elemental composition of the acinar cells is influenced by a variety of factors. Stimulation of fluid secretion by cholinergic, α-adrenergic or peptidergic agonists leads to a sustained increase of the Na/K ratio. The elemental composition and ultrastructure of the acinar cells of rat submandibular gland, as well as flow rate and composition of pilocarpinestimulated submandibular saliva are significantly affected by thyroxine, but less by the synthetic glucocorticoid dexamethasone. Hypercalcemia (induced by chronic vitamin D treatment) as well as hypocalcemia (induced by calcitonin) …

Determination Of Sulfur And Iron Valence By Microprobe, H. Kucha, R. Wouters, O. Arkens

Scanning Microscopy

SKα, SKβ and FeKβ valence related wavelength changes are large enough to be measured with microprobe spectrometers. The relative difference between S^2- and S⁶⁺ is measured as 1.27 eV for the SKα line and 1.66 eV for the SKβ line. This SKα and SKβ peak shift is function of the valence. Accurate microprobe measurement of the peak shift allows the determination of the sulfur valence in a microarea. The relative difference between Fe²⁺ and Fe³⁺ for the FeKβ line is 0.94 eV. Considering the achieved accuracy of measurements, this peak can only be used for an …

Prospects For Photo Electron Spectroscopy In A Scanning Transmission Electron Microscope, F. J. Pijper, A. J. Bleeker, R. J. Endert, P. Kruit

Scanning Microscopy

High spatial resolution microanalysis in scanning transmission electron microscopes is most easily performed when the specimen is inside a magnetic immersion objective lens. Recently a technique has been developed to perform spectroscopy of electrons that originate in this magnetic field. A very special form of photo electron spectroscopy is then possible for thin specimens in the microscope. An energy loss ΔE of a primary electron has the same physical effect as the absorption of a photon of energy ΔE. A coincidence measurement between energy loss electrons and the emitted electrons is expected to give a so called coincidence electron spectrum, …