bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of electron probe beam diameter by digital image processing
Authors: Oho Eisaku , Sasaki Toshihide , Adachi Koichi , Kanaya Koichi 
Published: February 2005

AbstractThe present report illustrates a computerized method for precise measurement of the diameter of an electron beam. The value of this measurement extends beyond simply providing an accurate estimate of resolution. Other salient areas which will benefit include quantitative X‐ray microanalysis, energy loss spectroscopy, diffraction studies, and electron beam lithography. The biological sciences as well as the material sciences will gain enormously from improved accuracy in measurement (control) of beam diameter. It is anticipated that most or all of the mathematical manipulations outlined in this paper will be incorporated into digital electronic packages which will perform the functions automatically for setting the electron beam diameter to the scientist's choice. The purpose of the present report is to indicate some of the principles involved so that as electron microscopy becomes more computerized and automated, the user will have some understanding of what the electronics are doing rather than simply depressing a button or two and ignoring the power of what resides within the walls of the instrument.The performance of a scanning electron microscope (SEM) and a scanning transmission electron microscope (STEM) is roughly determined by the incident electron probe beam size (diameter) involving a sufficient electron current. In the present paper, the diameter of an ultrafine electron beam is measured indirectly from the information given by the blurring of an edge in a STEM or a SEM image of a crystalline specimen with fine, sharp edges. The obtained data were processed by digital image processing methods which give an accurate value of the beam diameter. For confirming the validity of this method, a suitable simulation based on the convolution theorem was performed. By using this measurement, we could measure the diameter of an ultrafine electron beam down to 2 nm, which could not be measured easily by previous techniques.
Transmission electron microscopic analysis of kidney glomeruli obtained by fine‐needle aspiration
Authors: Rowden Geoffrey , Dean Shirley , Campbell James , Belitsky Philip 
Published: February 2005

AbstractAspiration biopsy of tumors and transplanted organs is a popular atraumatic method for diagnosis and also for the management of patients. Apart from the cytological analyses, it is clear that large aggregates of cells are obtained and these may be examined by electron microscopy. A study was carried out with dogs to assess the yield of intact glomeruli and tubules, resulting from a standard fine‐needle aspiration procedure. Employing a 20‐gauge needle, yields of approximately ten intact glomeruli were obtained with a tissue processing protocol that utilized filtration through a nylon mesh and backwashing, to resuspend the trapped aggregates. Processing for electron microscopy was carried out in microcentrifuge tubes. The ultrastructural preservation was excellent and the extension of these studies to investigations of not only renal transplantation, but also for diagnosis in human renal diseases of a broad spectrum, is suggested.
CTEM versus STEM versus HVEM: Evaluation of the three‐dimensional morphology of arsenic inclusions
Authors: Ramirez‐Mitchell R. , Sorensen E. M. B. 
Published: February 2005

AbstractElectron‐dense arsenic inclusions appeared in the nucleus of parenchymal hepatocytes from fish exposed to arsenate, but were absent in fish exposed under identical conditions to solutions lacking arsenic. Images of these inclusions were compared using conventional transmission electron microscopy (CTEM), scanning transmission electron microscopy (STEM), and high‐voltage electron microscopy (HVEM). Stereo pairs from the same individual inclusions were examined using each of these methods to provide a more complete understanding of their three‐dimensional organization and to evaluate the relative merits of each technique in the study of similar electron‐dense structures.Comparable results were obtained with the three types of instrumentation. Although HVEM is the technique of choice for the analysis of three‐dimensional images of such high electron‐dense structures, STEM proved to be a good alternate technique for the selection and general evaluation of samples in preparation for HVEM.
Ultrastructural morphometric image analysis applied to estimation of condensed chromatin in normal and neoplastic lymphocytes
Authors: Dardick Irving , Dardick Alexander M. , Jeans M. T. Diane , Rippstein Peter , Caldwell Douglas R. 
Published: February 2005

AbstractCurrently, quantitative studies of malignant lymphoma are being performed in an attempt to improve the classification of non‐Hodgkin's lymphoma (NHL) for diagnostic, prognostic, and therapeutic purposes. Morphometric image analysis is one method that can be employed in cases of NHL to obtain objective data of nuclear parameters; condensed chromatin being a compartment of the nucleus best measured at the ultrastructural level. This report assesses similarities or differences in the amount, distribution, and arrangement of condensed chromatin in nuclear profiles of normal and neoplastic lymphocytes in human surgical biopsy specimens. Morphometric data derived from electron micrographs of lymphocytes in germinal centers of lymph nodes with reactive hyperplasia (three cases) and small cell types of NHL two examples of malignant lymphoma, well differentiated lymphocytic type (ML, WDL) and three cases of malignant lymphoma, poorly differentiated lymphocytic type (ML, PDL) are compared. Results indicate that the distribution of condensed chromatin, i.e., the size of aggregates, and their spatial placement within the nucleus varies more than the amount (both mean area per profile or mean volume) of this nuclear parameter, and that this applies to normal as well as neoplastic lymphocytes. When a series of condensed chromatin parameters were statistically compared, no major differences could be detected between lymphocytes in normal tissues and those in ML, WDL and ML, PDL, but considerable differences were found in each of the nuclear morphotypes in the individual cases within the groups. This degree of variation in nuclear characteristics within normal tissues and the two lymphoma categories has not been previously recognized. Clearly, the technique of morphometric analysis, as applied to electron micrographs, can provide new and useful data that must be appreciated if classification schemes currently used in NHL are to improve and reflect biologic considerations.
A FORTRAN computer program for converting among atom, weight, and oxide percentages for use in analytical electron microscopy
Authors: Bigelow W. C. 
Published: February 2005

AbstractA FORTRAN program is given which will (1) calculate atom and weight percentages from a given chemical formula: (2) calculate atom percentages from given weight percentages; (3) calculate oxide percentages from given weight percentages; and (4) calculate weight percentages from given oxide percentages. The program is interactive, easy to use, and very convenient for use in electron beam microanalytical work.
Electron diffraction phenomena observed with a high resolution STEM instrument
Authors: Cowley J. M. 
Published: February 2005

AbstractBecause of the high brightness of the cold field emission source used in a dedicated scanning transmission electron microscopy (STEM) instrument, it is possible to focus electrons to a cross‐over of width 3Å or less and, with a suitable detection system, to obtain diffraction patterns from specimen regions of this size or greater. Coherent interference effects are visible in shadow images (in‐line holograms) and in convergent beam diffraction patterns. Special techniques have been developed for gathering information from the diffraction patterns for application to the study of the structures of crystal defects, crystal surfaces and small particles. Possibilities have been explored for holographic reconstruction from shadow images.
Modern electron microscopy for materials characterization
Authors: Thomas Gareth 
Published: February 2005

AbstractTo be successful, today's electron microscopist must have modern, well‐maintained facilities and be part of a team of experts with specific skills for research. Furthermore, in an ideal situation specific instruments should be dedicated to specific applications (high resolution, analytical, conventional, etc.), since in general the efficiency of a microscope varies inversely as its operations (and operators?). This is partly a reason for establishing national or regional electron microscopy centers, so that expertise and expensive equipment may be made available in central facilities.In this brief summary an attempt is made to illustrate how sophisticated methods of electron microscopy can be applied to practical problems by choosing representative examples from research at Berkeley using high resolution, high voltage, diffraction, and analytical techniques. More detailed examples have been given in some recent reviews (Thomas, 1984a, and Gronsky et al., 1985).
Three‐dimensional reconstruction of microtubule‐containing structures from electron micrographs
Authors: Murray John M. 
Published: February 2005

AbstractMicrotubules and associated structures are among the more difficult samples studied by 3D reconstruction techniques because of their size, complexity, and lability. Nevertheless, their importance in many cellular functions often justifies efforts to acquire 3D information up to the resolution limit of negatively stained specimens or beyond. A combined approach which utilizes methods appropriate to both helical symmetry and 2D crystal lattices seems to provide the surest route to 3D reconstruction. Images of unstained specimens obtained by newer techniques of microscopy present challenging problems in data analysis, but potentially offer higher‐resolution information.
Use of mixed glycosidase for the removal of mucus from the rat nasal epithelium in SEM studies
Authors: Monteiro‐Riviere Nancy A. , Jiang Xue‐Zhi 
Published: February 2005

AbstractThe surface layer of mucus, which obscures the epithelium from view, is a major obstacle when performing scanning electron microscopic studies of the nasal mucosa. Samples treated with a 1% mixed glycosidase solution for 1 or 2 minutes, followed by agitation, removed most of the mucus from the conchae without damaging the underlying epithelium. Removal of mucus allows the complete evaluation of the underlying epithelium in normal animals and the localization and characterization of lesions in animals exposed to nasal toxicants.
Monolayer freeze‐fracture—a modified procedure
Authors: Edwards Harold H. , Mueller Thomas J. , Morrison Martin 
Published: February 2005

AbstractMonolayer freeze‐fracture of biological membranes is a valuable tool for integrating membrane morphology with biochemical analysis of membrane components. This correlation has been restricted by the purity of the biochemical sample. In this article, the method is reviewed, and an improved method is described. The essential modification was the use of a polysaccharide‐coated microscope slide, instead of a copper plate, to cover cells attached to a polylysine‐coated coverslip. It was found that proper freeze‐fracture will not occur unless there is a distinct temperature gradient, with its accompanying stresses, across the cell monolayer during the freezing process. This gradient is achieved by using glass slides of different thickness to cover each side of the monolayer. Comparison of the results with those obtained when using a copper‐glass system demonstrated a consistently purer sample for the glass‐glass system, with whole‐cell contamination of the external membrane leaflet being reduced to 0.4%. Problems associated with obtaining pure samples for biochemical analysis are discussed, and the results of freeze‐fracture with the glass‐glass and glass‐copper systems are compared. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of polypeptides associated with the separate halves of the erythrocyte membrane demonstrated that band 3, the anion transport protein, separates with the cytoplasmic face, whereas only sialoglycoproteins and their fragments are retained in the external face. This finding, obtained with the glass‐glass system, is consistent with results of our earlier freeze‐fracture study that used a copper‐glass system which showed that covalent bonds may be broken during this procedure.
Wheat germ agglutinin fracture‐label of lymphocyte plasma and intracellular membranes
Authors: Torrisi Maria Rosaria , Pavan Antonio , Lotti Lavinia Vittoria , Frati Luigi 
Published: February 2005

AbstractConventional lectin cytochemistry or immunocytochemistry can be associated with freeze‐fracture in fracture‐label techniques: The thin section fracture‐label and the critical point drying fracture‐label. In the first method, which is particularly useful for investigating intracellular membranes, cells or tissues are freeze‐fractured, thawed, labeled, and embedded in resin. Wheat germ agglutinin labeling on freeze‐fractured human lymphocytes confirms the existence of two compartments of intracellular membranes, based on the sialoglycocomponent content.
Digital image processing for nonperiodic objects and an on‐line image processing system for high resolution electron microscopy
Authors: Baba Norio , Oho Eisaku , Mukai Makio , Kanaya Koichi 
Published: February 2005

AbstractA digital image processing method for noise removal and image enhancement in nonperiodic structural images is described. The method for noise removal uses a reversible transform between an image and image autocorrelation function. The Laplacian filter is then employed for image enhancement. Furthermore, an on‐line image processing system for highresolution TEM is presented.
Detection and identification of viruses by electron microscopy
Authors: Miller Sara E. 
Published: February 2005

AbstractElectron microscopy can aid in the rapid diagnosis of viral diseases, as it can be performed in a matter of hours, but on a routine basis it should be used in conjunction with other techniques. Initially, the specimen source and patient symptoms should be ascertained, as these will lend suggestions of possible agents while eliminating others; however, this information should not be allowed to prejudice observation in such a way as to cause oversight of an unlikely pathogen. Second, selection of the method of preparation should be based on sample consistency; extraction, debris clarification, concentration, tissue culture amplification, or embedment may be necessary. Finally, false‐positive results must be avoided by differentiating viruses from cell organelles or debris, mycoplasmal or bacterial contamination, and bacteriophages.
Freezing and drying of biological tissues with a toggle‐link helium freezer and an improved freeze‐drying apparatus: Application to neuropeptide immunocytochemistry
Authors: Coulter H. David 
Published: February 2005

AbstractA freezing apparatus has been developed for bringing blocks of tissue into contact with a block of sapphire chilled to 17°K. A toggle linkage minimizes rebound by slowing the rate of approach of the tissue to the cold surface to a velocity of zero. A glove box limits condensation on the surface of the sapphire, and a miniature moist chamber protects the specimen from drying and premature freezing. About 50 blocks of tissue can be frozen in an hour and a half by using 5 liters of liquid helium. The tissue is then frozendried at controlled temperature, fixed with OsO4 vapor, and infiltrated with epoxy resin in a simple bench‐top freeze‐drier without breaking vacuum. About two‐thirds of the blocks are useful for electron microscopy. Brain tissue frozen and dried by using these methods retains enough immunoreactivity for enkephalin in plastic sections to permit its detection with immunohistochemistry by using both the light microscope (with immunofluorescence) and the electron microscope (with colloidal gold).
Preparation of cross‐sectional TEM samples with observable thin sections at desired regions of non‐uniform surfaced semiconducting devices
Authors: Rai A. K. , Rashid M. H. , Pronko P. P. , Ezis A. , Langer D. W. 
Published: February 2005

AbstractTransmission electron microscopy of cross‐sectional samples offers an attractive means to study process evaluation and failure analysis of many semiconducting devices. In the present work, a technique to prepare cross‐sectional TEM samples, containing thin sections of specifically desired regions within nonuniform surfaced semiconducting devices, is described.
Biological variation in cryo‐microanalytical data from mouse small intestinal villi
Authors: Carr K. E. , Hayes T. L. , Watt A. , Klein S. , McKoon M. , Bastacky S. J. , Ellis S. 
Published: February 2005

AbstractMicroanalysis data obtained using low temperature scanning electron microscopy of frozen hydrated etched mouse duodenum gives information about peak/background ratios of various elements in different cellular compartments. The present paper describes ways in which the data can be analyzed to minimize artifactual variations and to make clear where there are genuine differences in peak/background ratios when readings from different animals are compared. Using these methods, it is shown that in some areas of villous epithelium there are measurable differences in the ratios of sodium, calcium, and sulphur.
Transmission and scanning electron microscopic examination of rat vaginal epithelium in the normal estrous cycle and in persistent estrous
Authors: Khosho Francis K. , Kaufmann Robert C. , Amankwah Kofi S. 
Published: February 2005

AbstractThe rat vaginal epithelium in both normal and persistent estrous (PE) cycles was examined by transmission and scanning electron microscopy utilizing cardiac perfusion and ruthenium red staining. It was demonstrated that surface vaginal epithelium in persistent estrous exhibited irregularly shaped cells. Borders were not well defined as is the case in normal estrous, and cells lacked the complex, interconnecting microridges and pits. Vaginal surfaces were completely smooth or covered with few microvilli. In the control specimens the fine structure en block stained with ruthenium red showed distinct cell membranes bordering the intercellular spaces between epithelial cells. With PE rats, this finding was absent, and there was instead a significant expansion of intercellular space with villiform processes of the cytoplasm projecting into the space. Utilization of the combination of techniques described provided the investigators with a better definition of vaginal tissue ultrastructure and revealed significant morphological differences between the normal estrous cycle and persistent estrous in vaginal specimens from rat models.
Preparation of cross sections of thin‐coated sheet steel for analytical electron microscopy observation
Authors: Selverian John H. , Marder Arnold R. , Notis Michael R. 
Published: February 2005

AbstractA method of preparing thinned cross sections of coated sheet steel (Galvalume) for observation in an analytical electron microscope (AEM) was developed. Steel panels dipped for 4 sec in baths of 55% by weight (wt pct) Al‐1.7 wt pct Si‐balance Zn, and 55 wt pct Al‐6.88 wt pct Si‐balance Zn at 610°C were examined. The ratio of the intensity of the K and L x‐ray lines from the same element was used in determining the foil thickness. The AEM results compared favorably to results obtained using electron microprobe analysis (EMPA).
Transmission and scanning electron microscopic examination of intracellular organelles in freeze‐substituted Kloeckera and Saccharomyces cerevisiae Yeast Cells
Authors: Baba Misuzu , Osumi Masako 
Published: February 2005

AbstractThe application of the conventional double‐fixation method (glutaraldehyde and osmium tetroxide) to whole yeast cells is difficult because the thick cell wall of the yeast prevents the penetration of osmium tetroxide. However, this problem was solved by using the freeze‐substitution fixation method. Therefore, it was possible to examine the intracellular structures of the yeast cells without digestion of the cell wall. In the present method, specimens for transmission electron microscopy and for scanning electron microscopy were prepared simultaneously. By scanning electron microscopic observation, three‐dimensional information about internal structures was obtained. In the cytological analysis of the yeasts, intracellular structures were well preserved by using the freeze‐substitution fixation method. On the outer leaflet of the nuclear envelope, many ribosomes were attached. The rough endoplasmic reticulum and Golgi apparatus were clearly seen in the yeast cytoplasm. The Golgi stack appeared to consist of smooth membranes, and small vesicles were present beside it. The details of other structures such as the nuclear division apparatus, actinlike filaments, and viruslike particles were also revealed. The present technique can be applied to most species of yeast cells. With this new information, the previous model of a yeast cell was modified.
Natural propane cryogen for frozen‐hydrated biological specimens
Authors: Ward Rob , Murray John M. 
Published: February 2005

AbstractThe properties of natural propane, mixed with 0–4% isopentane, as a cryogen suitable for rapid freezing of this layers of aqueous biological specimen suspensions are discussed. Although natural propane has rather variable properties, its freezing point can be depressed below the temperature of liquid nitrogen by adding a smaller amount of isopentane than is required for depressing the freezing point of pure propane.
Introduction of the protein G—gold complex for high‐resolution immunocytochemistry
Authors: Bendayan Moise 
Published: February 2005

AbstractProtein G, an immunoglobulin G‐binding molecule, was tagged with colloidal gold particles and was applied in immunocytochemistry. The present study reports the conditions required for the preparation of the protein G–gold complex and for its application in electron microscopy. Once used in combination with specific primary antibodies, the protein G–gold complex was able to yield highly specific labelings over particular tissue compartments. Various control experiments confirmed the specificity of the labelings obtained. Since the IgG‐binding properties of protein G are superior to those displayed by protein A, the protein G–gold appears a far better tool for high‐resolution immunocytochemistry.
Construction of 35‐millimeter camera adaptors for scanning electron microscopes
Authors: Miller Marcia M. , Hardy John , Revel Jean Paul , Rusnak Miro 
Published: February 2005

AbstractDescribed here is the construction of two 35‐mm camera adaptors for attachment to the recording monitors of scanning electron microscopes (SEM). The designs are simple and readily adaptable to almost any SEM. The choice of this camera format for recording SEM images is one of convenience as well as economy and does not sacrifice micrograph quality.