Biology Commons^™

Application Of Cathodoluminescence In Paint Analysis, W. Stoecklein, R. Göbel

Scanning Microscopy

When solving cases of burglary or investigating ship collisions, the forensic scientist frequently has to examine several layers of paint of the same color, often white. As a rule, the usual microscopic and spectroscopic methods [fluorescence microscopy, FT-IR (Fourier Transform Infrared Spectroscopy), pyrolysis, GC/MS (Gas Chromatography - Mass Spectrometry), etc.] are not sufficient to prove that the paint traces found on the scene, which are often only available in the form of fragments, originated from the same source as the reference material. It is possible to achieve convincing proof of this using either an optical cathodoluminescence-microscope or a cathodoluminescence-scanning electron …

On A Nature Of Cathodoluminescence Contrast Of Fine-Dispersed Structures In The Scanning Electron Microscope, M. V. Viskov, S. K. Obyden, G. V. Saparin

Scanning Microscopy

Fine-dispersed structures (FDS) consisting of a large number of microcrystalline or amorphous particles of different sizes and shapes were examined in cathodoluminescence (CL) mode scanning electron microscopy (SEM). Line dimension of each particle (about 10 - 100 μm) was larger than the electron beam diameter as well as electron scattering volume in material under investigation. An analysis of observed images showed the existence of some peculiarities in contrast which have not been observed in the CL-images for solid specimens. The FDS CL-image topographic contrast arises as a result of detection of CL-emission from an aggregate of FDS-elements surrounding an irradiated …

Electron Beam Induced Capacitance, O. V. Kononchuk, Eu. B. Yakimov

Scanning Microscopy

A model of signal formation in the Electron Beam Induced Capacitance (EBICap) mode of the Scanning Electron Microscopy (SEM) is proposed. In the frame of this model the possibilities of this technique are analyzed. It is shown that EBICap is suitable to obtain a local depletion region width and for mapping of this parameter. Experimental results demonstrating the potentialities of EBICap are presented.

Enamel Structure In Astrapotheres And Its Functional Implications, John M. Rensberger, Hans Ulrich Pfretzschner

Scanning Microscopy

Astrapotheres, large extinct ungulates of South America, share with rhinoceroses vertical prism decussation in the cheek tooth enamel. The similarity extends beyond merely the direction of the planes of decussation. The vertical decussation in astrapotheres is confined to the inner part of the enamel and has uniformly well-defined zones in which the prism direction differs by nearly 90° and the zones are separated by narrow transitional borders of intermediate prism direction. The outer enamel consists of predominantly occlusally and outwardly directed prisms. Within the outer enamel is a region of horizontally decussating prisms; here the angle of decussation is usually …

Mechanisms Of Ciliary Movement: Contributions From Electron Microscopy, Peter Satir

Scanning Microscopy

A brief review of important contributions of electron microscopy to the study of ciliary motility is presented. The electron microscope was used to show the universality of axonemal structure of cilia, and to develop the sliding microtubule model of ciliary motility and later the switch point hypothesis to explain the conversion of sliding into bending. Unexpectedly, insights into the importance of cilia in human health have stemmed from these studies.

Microwear And Striae Of Retzius Of Canines Of The Wild Japanese Monkeys (Macaca Fuscata), Teruyuki Hojo

Scanning Microscopy

This is a description of microwear and striae of Retzius of canine teeth of wild-caught female Japanese monkeys (Macaca fuscata) from Oita Takasakiyama, Kyushu. Micrographs were taken of high resolution casts using a scanning electron microscope (SEM). Before the casts were made, the diet of the captive monkeys was water-softened for three or four days. This softened diet probably added little wear to the surfaces of the teeth. These animals are part of a sample used in a previous report published in this journal. Others have observed that wild Japanese monkeys eat hard foods (such as grasshoppers, cicads …

Early Effects On The Morphology Of Mouse Small Intestine Of Single Or Combined Modality Treatment With Hyperthermia And X-Irradiation, G. R. Dickson, H. M. H. Kamel, S. P. Hume, M. Jaber, K. E. Carr

Scanning Microscopy

This study describes the effects of hyperthermia and X-irradiation on the morphological appearance of normal, at risk tissues in the ileum of the mouse. The early morphological effects day after a combined modality treatment are compared with those due to either hyperthermia or X-irradiation given alone. The response was assessed qualitatively and semiquantitatively using scanning electron microscopy and a villous scoring technique.

Early post-irradiation effects on topography did not differ significantly from those observed after small intestine exteriorisation without treatment. The villous scores for the combined modality treatments reflected greater damage than would be expected from the sum of villous …

A Preparation Protocol For Postembedding Immunoelectron Microscopy Of Dictyostelium Discoideum Cells With Monoclonal Antibodies, Bruno M. Humbel, Elke Biegelmann

Scanning Microscopy

On-section-labelling of Dictyostelium discoideum cells poses severe problems in retaining adequate morphology and antigenicity. Monoclonal antibodies are an essential tool in biochemistry and molecular biology because of their specificity and low. background staining. Unfortunately their advantage, the recognition of only one distinct epitope, is often a handicap for immunoelectron microscopy. Resin embedding and steric hindrance of the gold-tagged secondary antibodies further reduce the efficiency in detecting antigens making the localization of less abundant antigens difficult if not impossible. A successful preparation protocol should retain morphology and antigenicity, allow the antibodies easy access to the antigen and use a detection system …

Three-Dimensional Characterization Of Dense Bodies In Contracted And Relaxed Mesenteric Artery Smooth Muscle Cells, Linda J. Mcguffee, Sally A. Little

Scanning Microscopy

We have previously shown that dense bodies are not the static planar simple ovoidal structures they appear to be in thin sections. In this report, we present three-dimensional reconstructions from consecutive serial thin sections through shortened and non-shortened large mesenteric artery cells. Profiles of the cell surface, membrane dense bodies, and cytoplasmic dense bodies were reconstructed from consecutive thin sections and the distribution, size, shape, and spatial relationships among these components was examined. Within the cell, membrane dense bodies are numerous and occupy approximately 10% of the cell volume. Membrane dense bodies can attach to the cell surface laterally, obliquely …

Review And New Case Reports On Scanning Electron Microscopy Of Pili Annulati, Monilethrix And Trichothiodystrophy, K. Meyvisch, M. Song, N. Dourov

Scanning Microscopy

Pili annulati, Monilethrix and Trichothiodystrophy are uncommon conditions in which the hair shaft has a distinct appearance as seen by optical microscopy and scanning electron microscopy (SEM). We report several new cases and review the characteristic ultrastructural abnormalities investigated by SEM.

Pili annulati: abnormal areas which show a longitudinal, "curtain-like" folding of the cuticular cells, alternating with normal areas. The latter present regularly non-systematized, superficial depressions. Hair specimens of the patient's mother show the same surface irregularities.

Monilethrix: most hair shafts show variations in thickness giving a typical nodal appearance. In the isthmus area we noticed longitudinal ridging …

Cryofixation Of Tissues For Electron Microscopy: A Review Of Plunge Cooling Methods, Keith P. Ryan

Scanning Microscopy

This review of cryofixation by plunge cooling surveys liquid coolants, plunge cooling devices, modeling and applications featuring time resolution. It then focuses on thermocouple experiments and ice crystal analyses. These highlight the effects of the design of specimen holders, the cold gas above the coolant which can freeze the specimen prematurely, specimen size, plunge velocity, coolant depth and ultimate coolant efficiencies. The ice crystal cavity analyses are validated by experiments which monitor the effects of high subzero temperatures on the storage of plunge cooled specimens and an experiment which monitored the rate of cryosubstitution. Ethane was found to be more …

Scanning Electron Microscopy Of The Mammalian Organ Of Corti: Assessment Of Preparative Procedures, A. Forge, G. Nevill, G. Zajic, A. Wright

Scanning Microscopy

Different fixation, drying and coating procedures have been applied in preparation of the organ of Corti for scanning electron microscopy (SEM), and structural features of the apical surface of the tissue in unfixed, freeze-fractured preparations used in assessing their effects on morphology. Fixation with glutaraldehyde alone or osmium tetroxide alone causes artefacts that are substantially avoided when tissue is doubly fixed in glutaraldehyde followed by osmium. Significant improvements in preservation are also obtained when tissue is additionally processed through thiocarbohydrazide-osmium (TOTO) processing. In addition to providing a conducting coat, it stabilises the tissue against deformations that might otherwise occur during …

Scanning Electron Microscopic Studies Of The Oral Mucosa And Its Microvasculature: A Review Of The Palatine Mucosa And Its Microvascular Architecture In Mammals, Y. Ohta, S. Okada, I. Toda, H. Ike

Scanning Microscopy

The present paper deals with the microvascular architecture of the palatine mucosa in primates, camivorae, and rodentia utilizing microvascular corrosion castings and epithelium-separated specimens.

The submucous vascular network is under-developed since the bard palatine mucosa was designated the mucoperiosteum, except some areas. The palatine venous plexus appears to show regional differences with animal species differences. The well-developed plexus is observed to be two-layered and may contribute to the process of regurgitation of rough food and assist in mastication with the palatine plicae. Formation and patterns of the arterial network in the lamina propria are in a close relation with connective …

The Use Of Organ Cultures To Study Vessel Wall Pathobiology, Edward W. Y. Koo, Avrum I. Gotlieb

Scanning Microscopy

Organ culture of the vessel wall is an useful in vitro method to study vascular cell biology. The intact vessel allows for the study of cell-cell and cell-substratum interactions including the structure and function of the vessel wall matrix. Long term organ cultures of porcine aorta show that neointimal formation is due primarily to cell proliferation of pre-existing intimal smooth muscle cells. Neointimal formation in these cultures is more pronounced in the presence of an endothelium that is turning over. In endothelial wound repair studies, the endothelium of the organ culture shows some important differences when compared to tissue culture …

Off-Line Data Evaluation Of Elemental Maps Obtained From Scanning Nuclear Microprobe Analyses, N. E. G. Lövestam, E. Swietlicki

Scanning Microscopy

The results of scanning nuclear microprobe (SNM) analyses are normally presented as elemental maps showing the number of detector events, acquired within a certain energy region, for every pixel irradiated. Such elemental maps can be misleading if they are interpreted as directly reflecting the variations in the elemental concentrations across the analysed sample. The aim of this paper is to demonstrate how such elemental maps can be treated in order to facilitate the interpretation and extract the information contained in the data set, such as the covariation between elements. Examples of sample thickness correction, image processing and spectrum filtering as …

Detection Of X-Ray Damage Repair By The Immediate Versus Delayed Plating Technique Is Dependent On Cell Shape And Cell Concentration, Nandanuri M. S. Reddy, Maria Kapiszewska, Christopher S. Lange

Scanning Microscopy

A method commonly used to measure the ability of cells to repair potentially lethal damage (PLD) is to compare immediate plating (IP) and delayed plating (DP) survival. Lower cell survival under IP conditions relative to that after DP conditions has been interpreted to indicate a higher ability of cells to repair potentially lethal damage (PLO) under DP conditions. However, this IP radiosensitization has not been observed in several cell lines and tumor models. IP conditions involve treatment of cells with trypsin and plating them into fresh growth medium. We have investigated the possibility that radiosensitization under IP conditions may be …

Structure Of Rat Kidneys Following Microwave Accelerated Fixation, Jayashree A. Gokhale, Saeed R. Khan

Scanning Microscopy

In contrast to fixation of tissue in externally heated fixative, microwave-irradiation can generate uniform internal heat, which is of utmost importance for successful fixation of biological tissue. To evaluate the effectiveness of microwave-accelerated chemical fixation, we compared the structure of rat kidney fixed by a conventional method and a microwave-accelerated method, by scanning and transmission electron microscopy. Following perfusion, rat kidney pieces 1-2 mm in size were irradiated in Karnovsky's fixative in a domestic Amana microwave oven, till the temperature of the fixative reached 45-50°C. For conventional fixation, tissue pieces were fixed overnight at room temperature in the same fixative. …

Silicified Mississippian Paleosol Microstructures: Evidence For Ancient Microbial-Soil Associations, Ray Kenny, David H. Krinsley

Scanning Microscopy

Silica-replaced microfeatures in a well-developed, Upper Mississippian paleosol from north-central Arizona, were examined by scanning electron microscopy using back-scattered electron imagery. Preserved microfeatures include hollow and solid tubiform filaments and mycelium-like stringers which radiate from problematic (biogenic?) soil structures. Preservation of these features suggest that microstructures in the soil zone are not uniformly destroyed during post-diagenetic silica replacement and that biological soil symbionts may have occurred as early as the Upper Mississippian (~280 Mya).

Scanning Electron Microscopy Of A Soil Fungus Gliocladium Roseum, David Jones, Derek Vaughan, William J. Mchardy

Scanning Microscopy

The paper describes the ultra-structural features of cryofixed and critical point-dried sporing cultures of a soil fungus Gliocladium roseum. Features described are Acrostalagmus-like conidiophores with spore masses in mucoid balls borne at the tips of branchlets and penicillate heads with conidia massed in rope-like formations. A particular feature of the aerial hyphae and conidiophores is the presence of blister-like swellings on their walls. These observations help to accurately characterize the organism in taxonomic studies.

The Diagnostic And Phylogenetic Significance Of Widened And Pronged Hamuli In Feathers, Tim G. Brom, Uri Frank

Scanning Microscopy

The taxonomic distribution of widened and/or pronged hamuli (hooklets) on distal barbules in the pennaceous part of feathers was studied with light microscopy (LM) and scanning electron microscopy (SEM) in order to assess the diagnostic and phylogenetic significance of these structures. Comparison of the LM and SEM appearance of these structures indicates that "thickened" hamuli are artifacts, arising from the misinterpretation of rotated tape-like structures. Pronged hamuli, on the contrary, are non-artifacts. These structures have a much wider taxonomic distribution than was reported by earlier workers, and therefore do not seem to be useful for identifying feather fragments.

The Influence Of Dietary Factors On The Risk Of Urinary Stone Formation, A. Hesse, R. Siener, H. Heynck, A. Jahnen

Scanning Microscopy

The action of various beverages and foods on the composition of the urine in the circadian rhythm and in the 24-hour urine has been investigated under standardized conditions. Orange juice leads to a significant increase of urinary pH and citric acid excretion. Black tea leads to a raised excretion of oxalic acid by only 7.9%. In the short term, beer increases diuresis, but afterwards leads to a compensatory antidiuresis with increased risk of stone formation. Depending on their composition, mineral waters have very different effects on the urinary constituents. Milk as well as cocoa beverage significantly increase calcium excretion; moreover, …

Particle Induced X-Ray Emission Microanalysis Of Root Samples From Beech (Fagus Sylvatica), M. Hult, B. Bengtsson, N. P. -O. Larsson, C. Yang

Scanning Microscopy

Beech seedlings (Fagus Sylvatica) were grown in a nutrient solution to which AlCl₃ had been added. The experiments were designed to evaluate the effect of aluminum on the localization of elements in plant root tissue. Cross-sections of roots were analyzed with micro-PIXE (particle induced X-ray emission) and Rutherford backscattering (RBS) simultaneously. A proton beam of either 30x30 μm² or 5x5 μm² was scanned over the samples, and quantitative elemental maps were created. Aluminum was found to accumulate in high concentrations (percent levels) in the epidermis and the outer layer of the cortex, when the nutrient …

Relationship Between Villous Shape And Mural Structure In Neutron Irradiated Small Intestine, K. E. Carr, J. S. Mccullough, A. C. Nelson, S. P. Hume, S. Nunn, H. H. M. Kamel

Scanning Microscopy

Previous work on irradiation of mouse small intestine has assessed the changes produced by counting crypts/microcolonies, scoring villous shape or examining morphological changes in specific parts of the wall.

This paper used scanning and transmission electron microscopy to study the effects of whole body irradiation with 5 Gy neutrons on the surface and internal features of the intestinal wall of CFLP mice, 1 day, 3 days and 7 days after treatment.

Empirical scores from the ultrastructural findings were inserted into a Morphological Index display calculated from analytical data based on cell counts and area measurements obtained from resin histology sections. …

An Improved Method For Preparing Microvascular Corrosion Casts Of Rat Embryos, S. Yoshida, J. Chiba

Scanning Microscopy

This paper presents an improved method for preparing microvascular corrosion casts of rat embryos (day 16.5-21.5). Special attention was paid on the viscosity of the casting material, the method of mechanical restraint, and the subsequent drying of the casts. The embryos were perfused with Mercox resin diluted with 25% methyl methacrylate monomer followed by undiluted Mercox resin to avoid outflow of resin from the vasculature after perfusion. The specimens were mounted on a stainless steel plate with self-curing resin to prevent flotation, mechanical damage, and collapse of the cast specimens following preparation. After digestion and washing, the cast specimens were …

Scanning Electron Microscopy And Energy-Dispersive X-Ray Microanalysis Studies Of Early Dental Calculus On Resin Plates Exposed To Human Oral Cavities, T. Kodaka, Y. Ohohara, K. Debari

Scanning Microscopy

Dental calculus formed after 10 days on resin plates, applied to the lingual sides of the mandibular gingival regions in eight human subjects, was investigated by means of scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDX). The mineral deposits were mainly divided into three types: A, B, and C. The type A deposits showing an average Ca/P molar ratio of 1.42 were densely packed with fine needle-shaped crystals formed by the intra- and extracellular calcification. The type A deposits, probably composed of Ca-deficient apatites and the transitional forms between apatite and octacalcium phosphate (OCP), were observed in all subjects. …

A Review Of Graphite And Gold Surface Studies For Use As Substrates In Biological Scanning Tunneling Microscopy Studies, Carol R. Clemmer, Thomas P. Beebe Jr.

Scanning Microscopy

The current status of biological Scanning Tunneling Microscopy (STM) investigations and the importance of using a well-characterized substrate are discussed. The findings of over two years of experiments and over 1,000 images obtained on gold substrates prepared by a variety of different methods are statistically summarized and compared to a very flat reference substrate, highly oriented pyrolytic graphite (HOPG). In an effort to begin to corroborate STM results with those obtained from other more established techniques, the results of Auger Electron Spectroscopy (AES) and Electron Spectroscopy for Chemical Analysis (ESCA) of biomolecular STM samples are presented.

Can We See Living Structure In A Cell?, Gilbert N. Ling

Scanning Microscopy

Colloid chemistry (κολλα: glue, or gelatin) was introduced in 1861 after the discovery of protoplasm which exhibits gelatin-like properties. Some 80 years later, colloid chemistry (and with it, the concept of protoplasm) was largely abandoned. The membrane (pump) theory, according to which cell water and cell solute like K⁺ are free as in a dilute KCl solution, became dominant. Later studies revealed that rejecting the protoplasmic approach to cell physiology was not justified. Evidence against the membrane (pump) theory, on the other hand, has stood the test of time. In a new theory of the living cell called the …

The Scanning Probe Microscope, J. Jahanmir, B. G. Haggar, J. B. Hayes

Scanning Microscopy

Scanning probe microscopy bas evolved into a powerful tool since its inception in 1982. The scanning probe microscope bas found applications in metrology, spectroscopy, and lithography. We will review the background of the technology, discuss the different types of scanning probe microscopes including the scanning tunneling microscope and the scanning force microscope, and present many of the applications for the instrument.

Correction For Extraneous Background In X-Ray Microanalysis Of Cell Cultures, Anne Von Euler, Romuald Wróblewski, Godfried M. Roomans

Scanning Microscopy

Some practical aspects of the X-ray microanalysis of cell cultures have been investigated. Cells were cultured on titanium grids covered with Formvar films and analyzed at 100 kV either in the scanning transmission (STEM) or transmission mode (TEM) of the electron microscope. Different holders, grids and configurations were compared with respect to the relative contribution of different factors to the extraneous background in the X-ray spectrum. When low atomic number holders are used, the contribution to the spectrum of electrons scattered through high angles, may be negligible. In practice this may result in negative values for the contribution of these …

Scanning Electron Microscopy - Energy Dispersive Spectroscopy And X-Ray Diffraction Analyses Of Human Salivary Stones, H. Mishima, H. Yamamoto, T. Sakae

Scanning Microscopy

Ten salivary stones in the human submandibular gland were investigated by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction analyses. The stones usually showed a lamellar pattern. SEM observations revealed cubical, plate-like, granular, small and large granules, polyhedral or globular structures in these stones. By X-ray powder diffraction analysis, the main constituents of salivary stones were found to be apatite and whitlockite. SEM-EDS analyses showed that Ca and P were the major elements, frequently accompanied by Mg and S, and less frequently by Na, Al, Si, Cl, K, Fe, Cu and Zn. Ca/P molar ratios ranged from 1.00 to …