bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory use of the personal computer: A program in MS‐DOS BASIC, for generating specimen labels and data sheets for electron microscopy
Authors: Ulrich Roger G. 
Published: February 2005

AbstractConventionally, all specimen vial and block labels are handwritten or typed, a labor‐intensive process open to human error, particularly in a lab that processes large numbers of samples. The computer program described in this report was developed to reduce or elimiate this problem. The program is menu‐driven, asking specific information from the user, and runs on an IBM PC (or compatible). It is designed to accurately produce specimen collection vial labels, resin block labels, and data sheets for inclusion in a research notebook. A task that in the past may have required much time at the typewriter can now be accomplished without error in a few minutes. Although designed to fit the needs of a pathology laboratory, the program (written in BASIC) can be easily modified to fit other applications.
Structural and functional correlates of synaptic transmission in the vertebrate neuromuscular junction
Authors: Rash John E. , Walrond John P. , Morita Michio , McCracken Thomas O. 
Published: February 2005

AbstractBecause vertebrate neuromuscular junctions are readily accessible for experimental manipulation, they have provided a superb model in which to examine and test functional correlates of chemical synaptic transmission. In the neuromuscular synapse, acetylcholine receptors have been localized to the crests of the junctional folds and visualized by a variety of ultrastructural techniques. By using ultrarapid freezing techniques with a temporal resolution of less than 1 msec, quantal transmitter release has been correlated with synaptic vesicle exocytosis at discrete sites called “active zones.” Mechanisms for synaptic vesicle membrane retrieval and recycling have been identified by using immunological approaches and correlated with endocytosis via coated pits and coated vesicles. In this review, available ultrastructural, physiological, immunological, and biochemical data have been used to construct an ultrastructural model of neuromuscular synaptic transmission that correlates structure and function at the molecular level.
A surface durable and strongly bonded phosphor viewing screen for T.E.M.
Authors: Beauregard Paul 
Published: February 2005

AbstractA simple procedure is described for the preparation of a totally inorganic, durable, strongly bonded, and non‐shrinking phosphor viewing screen. The procedure requires no special apparatus or skills in order to prepare a fairly uniform high resolution screen in only about 0.5 hours plus drying time. The screens are suitable for use on an automatic exposure system where mechanical shock can destroy a screen.
Synaptic organization of primary axons in trigeminal nucleus oralis
Authors: Falls William M. 
Published: February 2005

AbstractThis report examines the morphology and synaptic connections of small‐diameter primary trigeminal axons that terminate in the border zone (BZ) and ventrolateral (VL) subdivisions of rat trigeminal nucleus oralis (Vo). Primary axons were made visible for light and electron microscopic analysis by utilizing the method of anterograde transport of horseradish peroxidase. BZ receives the terminal arborizations of two different populations of small‐diameter primary axons. One of these arises from unmyelinated parent fibers and terminates in the dorsal one‐half of BZ, while the other has small myelinated parent branches that arborize throughout the subdivision. Terminating within VL are the arbors of a second population of small myelinated primary axons. The endings of all three populations of primary axons lie in synaptic glomeruli. Endings in both subdivisions derived from small myelinated parent fibers lie centrally in glomeruli. Those in VL form axodendritic synapses on numerous dendritic shafts and spines, while endings in BZ glomeruli make at least one axodendritic synapse on one or two dendritic shafts. Endings of unmyelinated primary axons in BZ lie at the periphery of glomeruli where each forms a single axodendritic synapse on a central dendrite. It is at these asymmetrical axodendritic synapses that these three populations of primary axons are thought to transfer their inputs directly to the dendritic arbors of second‐order BZ and VL neurons. Common to all three glomeruli is one or more small axonal endings filled with flattened synaptic vesicles that establish axoaxonic synapses on the primary ending as well as axodendritic synapses on the dendritic element(s) receiving primary input. In view of their symmetrical to intermediate synaptic contacts, these endings are thought to belong to axons derived from at least one source that can inhibit or diminish the firing rate of second‐order BZ and VL neurons in response to primary input.
Cellular mechanisms controlling the strength of synapses
Authors: Wilson Charles J. 
Published: February 2005

AbstractThe mechanisms suspected as contributors to the regulation of synaptic strength act at a variety of sites along the causal chain that links activity in a presynaptic neuron to activity in a postsynaptic one. At several places in this chain, morphological factors are expected to have a powerful influence, and at several others, key insights into the mechanisms controlling synaptic action have been achieved using morphological techniques. A variety of presynaptic mechanisms controlling the release of neurotransmitter have been most directly shown to regulate the potency of synaptic connections. Traditional interpretations of the effect of postsynaptic geometry on synaptic strength need to be reevaluated in light of new views of the functional properties of dendritic membrane, and the new neurophysiological data must be incorporated into a more comprehensive view of the behavior of spatially distributed excitable membrane with specific patterns of distributed synaptic inputs.
Digital image processing of crystalline specimens examined by electron microscopy
Authors: Kanaya Koichi 
Published: February 2005

AbstractCrystalline specimens imaged in the electron microscope are analysed using digital processing. Some principles of structural analysis using the method of Fourier decomposition are discussed. Complementary techniques, such as enhancement by gradient and Laplacian operators, have been found useful in analysing electron micrographs.The application of these techniques to some problems in Materials Science and Biology are reviewed. By selecting and phase‐correcting spots in the computed diffraction pattern, it was possible to localize atoms, molecules, and their defective arrangement in evaporated gold, sputter‐deposited tungsten films, and single crystals of cadmium selenide.Digital processing based on the theory of helical diffraction was used to explore the three‐dimensional arrangement of molecules in cellular components of alveolar soft part sarcoma, Hirano bodies, and neurofibrillar tangles in the human brain.
Differential morphometric values induced in Golgi apparatus of higher plant cells by aldehyde and permanganate fixation
Authors: Gonzalez‐Reyes José A. , Gracia‐Navarro Francisco , Garcia‐Herdugo Gregorio , Hidalgo Antonio , Navas Plácido 
Published: February 2005

AbstractIn order to determine the best conditions to carry out quantitative ultrastructural studies in plant specimens, five different fixation techniques, including some of the most reported electron microscopy fixatives (glutaraldehyde‐paraformaldehyde, osmium tetroxide, potassium permanganate), were assayed in onion root meristems to check their ability to induce morphometric changes in Golgi apparatus ultrastructure. Although the parameters evaluated showed in all cases the same tendency, values obtained after permanganate fixation were always higher than those found after aldehyde techniques (especially aldehyde‐osmium). Aldehyde followed by osmium fixation appears as the most indicated fixation method when accurate quantitative ultrastructural studies are to be developed.
A new freeze‐drying device for platinum replica studies of cell surface and cytoskeleton: An example using immunogold‐labeled human erythrocytes
Authors: Lupu Florea , Constantinescu Elena 
Published: February 2005

AbstractWe designed and built a freeze‐drying device that ensures the protection of the specimens against contaminants during mounting on the cold stage of the freeze‐fracture machine, transferring into the vacuum chamber and deep etching. The device consists of a copper cap that covers the specimen and a thermal connection that ensures thermal transfer between the microtome arm and the copper cap. This device was used to study the ultrastructural features of the erythrocyte membrane skeleton and the immunocytchemical localization of spectrin in an “in situ” approach, by freeze drying and platinum rotary shadowing. Human erythrocytes adhered to polylysine‐coated coverslips and were broken by a stream of buffer that mimics the intracellular ionic environment (“inside buffer”). The samples were prefixed in periodate‐lysine‐paraformaaldehyde fixative, labeled with antispectrin 5‐nm gold particles, fixed in glutaraldehyde, mordanted in tannic acid, postfixed in OsO4, repeatedly washed in water, rinsed quickly in 30% ethanol, freeze‐dried, and rotary‐shadowed. Electron microscopic examination of the replicas revealed the skeletal network on the inner surface of the erythrocyte membrane. Immunocytochemical labeling proved that spectrin represents a fibrillar component of the network. Our data confirm the speculative model of the molecular organization of the erythrocyte skeleton, based on studies on in vitro association of proteic constituents. Both the technique and the device developed by us may lead to a deeper understanding of the spatial organization of the cytoskeletal network of more complex cell types.
Calibration methods for quantitative image processing in electron microscopy
Authors: Lamvik Michael K. , Davilla Scott 
Published: February 2005

AbstractAn image can be represented digitally as a matrix of numbers. When those numbers are linearly related to a property of the object, such as mass per unit area, a simple integration of an image area leads to a total of that property, such as the mass of a particle that is represented in a selected area.Following techniques pioneered by Bahr and Zeitler, we illustrate the use of photographic densitometry of films exposed in an electron microscope to measure electron scattering. The transmission of an electron micrograph will be linear with respect to mass thickness for a particular value of background brightfield density, hence allowing determination of the mass of microscopic particles. We show here a digital computer method for conveniently establishing the linear condition by quantitative image processing using micrographs of polystyrene spheres. The method also serves to produce calibration curves for cases where the transfer from transmission to mass thickness is not linear. We also illustrate how an inexpensive computer is used to display and integrate regions of micrographs to determine particle mass.
Preparation of collagen gel matrices for light and electron microscopy
Authors: Turner J. W. , Sandra A. 
Published: February 2005

AbstractCells grown on type I hydrated collagen gels require special techniques for sample preparation and processing in order to optimize the removal of all reagents from the collagen matrix and prevent artifactual shrinkage. This method includes cutting out a small block of the collagen gel, postfixation, and transfer to a scintillation vial for further processing. These additional steps ensure that all sides of the block will come in contact with solutions and reduces the possibility of reagent trapping within the collagen matrix. Additionally, in our study the collagen gel and endothelial cells that form a monolayer on the surface are oriented to allow the microtomist greater assurance of cutting true cross sections, thus saving time and increasing reproducibility. The dehydration sequence is also modified, with an increase in the times and additional steps, especially in the higher concentrations of dehydrant.
Which image parameter(s) for the automation of the electron microscope?
Authors: Bonnet N. , Zinzindohoue P. 
Published: February 2005

AbstractExperiments on automating the transmission electron microscope rely on the search for minimum variance. This image parameter gives satisfactory results for automatic focusing, astigmatism correction, and beam alignment. We investigate here the different image descriptors that might also be used; we conclude that texture parameters, which are directional, would be better candidates correcting astigmatism and beam tilt.
Examples of high‐resolution electron microscopy (HREM) investigation of complex oxides related to perovskite
Authors: Hervieu Maryvonne 
Published: February 2005

AbstractThe properties of oxides may be drastically influenced by their microstructures. Thus the knowledge of nonstoichiometric mechanisms is an essential tool for the conception of new inorganic compounds by solid‐state chemist. Through three chosen examples of complex oxides with perovskite‐related structure, these points are illustrated. The new families of phosphate tungsten bronzes, the antiferromagnetic AMn1 − x FexO3 – y, and the copper oxides LCuO3 – x (La = Ba, Y, La) were studied by high‐resolution electron microscopy (HREM) in order to analyze the mechanisms of nonstoichiometry, the defects of which can modify their physical properties (magnetism or electronic conductivity) and the factors that govern their stabilization.
Electronic core level microanalyses and microscopies in multipurpose apparatus
Authors: Cazaux Jacques , Gramari Daniel , Jbara Omar , Mouze Dominique , Nassiopoulos Androula , Thomas Xavier 
Published: February 2005

AbstractUsing an instrument equipped with two electron guns, an electron analyzer, and a Si(Li) diode detector, we developed microanalytical techniques based on inner‐shell electron excitations by incident electrons and X‐rays, that is, electron energy‐loss spectroscopy (EELS) in the reflection mode; electron probe microanalysis (EPMA) and X‐ray appearance potential spectroscopy (XAPS); electron‐induced Auger electron spectroscopy (e‐AES); X‐ray photoelectron spectroscopy (XPS), X‐ray absorption spectroscopy (XAS); X‐ray induced AES (XAES), X‐ray fluorescence analysis (XRF), and scanning X‐ray radiography (SXR). The corresponding characteristic images (including X‐ray microradiography and X‐ray photoelectron microscopy) were obtained in the scanning mode. The principle of the apparatus is described. Each spectroscopy and microscopy is illustrated by an example. Their performance and limits are discussed.
Transmission electron microscopy studies in relation to production of solar cells from polycrystalline silicon sheets (R.A.D. process)
Authors: Gervais Annick 
Published: February 2005

AbstractRibbon against drop (R.A.D.) ribbons exhibit a polycrystalline texture similar to that of most melt‐grown ribbons; we review here the defects of as‐grown materials as well as after the solar cells' production.
An application of high‐resolution transmission electron microscopy to the study of the fine structure of dislocations in potassium feldspars
Authors: Zheng Yuanlin , Gandais Madeleine 
Published: February 2005

AbstractAn application of high‐resolution transmission electron microscopy (HRTEM) to the study of two types of dislocations in potassium feldspars (K‐feldspars) is shown here. HRTEM images were submitted to a filtering in order to improve their interpretation. One type of dislocation—(010)[001]/2—appears to be dissociated, with (010)[001]/2 planar defect, whereas the other one—(010)[110]/2—is perfect. This result helps provide an understanding of dislocation activation in this material.
Optimal preparatory procedures of cryofixation for immunocytochemistry
Authors: Ichikawa Misao , Sasaki Katsunori , Ichikawa Atsushi 
Published: February 2005

AbstractTo examine the optimal preparatory procedures of cryofixation for immunocytochemistry, the labeling density over the antigenic sites in cells processed by various protocols of freeze‐substitution and embedding was quantitatively evaluated. Fresh tissue blocks of gerbil parotid gland were quickly frozen by a metal contact method using liquid helium and freezesubstituted with one of the following media: 4% OsO4 in acetone or 0.4% OsO4 in acetone or 0.3% glutaraldehyde in acetone. They were then embedded in either an Epon‐Araldite mixture or Araldite 6005, which were polymerized at 60°C and 50°C, respectively. Some frozen samples substituted with aldehyde‐containing acetone were embedded in Lowicryl K4M (polymerized at —30°C). Immunocytochemical localization of amylase was examined by indirect immunostaining by using antigerbil parotid amylase antibody and protein A/gold complex. Thin sections of epoxyresin‐embedded materials were treated with oxidizing agents before immunostaining. The central dense core of heterogeneous secretory granules in the acinar cells was heavily labeled with immunogold, regardless of substitution media and embedding resins employed. The labeling density on thin sections of all the cryofixed materials examined was about 1.5 times or more as high as in those processed by conventional chemical fixation. The highest value of the labeling density was obtained from material which was substituted with 0.3% glutaraldehyde in acetone and embedded in Araldite 6005. Substitution with osmium‐containing acetone appeared not to seriously affect immunoreactivity of the antigenic sites and was advantageous because of the distinctive images of membranes. Advantages and disadvantages of the individual protocols employed are discussed.
High‐resolution electron microscopy of ceramic interfaces
Authors: Ishida Yoichi , Hagege Serge , Ichinose Hideki , Takahashi Yutaka 
Published: February 2005

AbstractThree observations described here were chosen not only to represent our recent interface studies in ceramics, but also to demonstrate how different the present status of interface research is with respect to the level of high‐resolution electron microscopy. Certain common features may be found among the problems of ceramic interface studies. Importance of basal plane grain boundary, for example, is one of the characteristics of this type of heterogeneous compound. The crystalline heterogeneity has been ignored largely in the grain boundary structure study since it has been developed primarily for cubic metals. The new area of basic grain boundary interface structure study is opened now that description of this type of interface has become engineeringly important.
Adrenal chromaffin cells as transplants in animal models of parkinson's disease
Authors: Hansen John T. , Bing Guoying , Notter Mary F. D. , Kordower Jeffrey H. , Fiandaca Massimo S. , Gash Don M. 
Published: February 2005

AbstractThe field of neural transplantation has moved rapidly forward in the last decade. Initially, fetal cells were used as implants to investigate their potential to ameliorate deficits in animal models of Parkinson's disease. However, because of the moral and legal problems associated with the use of fetal tissues in humans, alternative sources of donor tissue were sought which possessed the structural and functional characteristics needed to improve motor function in Parkinsonian patients. To date, one of the most promising tissues being investigated is the adrenal medulla, whose chromaffin cells possess an inherent plasticity of form and function. Transplanted chromaffin cells currently are being studied by a variety of approaches, including electron microscopy, in mouse, rat, and primate models of Parkinson's disease. An overview of the role of the chromaffin cell in this exciting and clinically important arena is briefly reviewed, with an emphasis on the fine structure of implanted chromaffin cells.
Mitotic cell division in the extraadrenal chromaffin system of various species
Authors: Mascorro Joe A. , Yates Robert D. 
Published: February 2005

AbstractMitotic activity often has been reported in embryonic and fetal sympathetic neuroblasts, principal sympathoblasts, and primitive sympathetic cells in various species at different stages of development. Postnatal adrenal medullary cells also are known to undergo mitosis, but such dividing capabilities rarely have been observed in the true postnatal extraadrenal chromaffin system. Although few in number, this work nevertheless has clearly identified such cells in varying stages of the mitotic cycle in the young dog, Syrian hamster, mouse, rabbit, and rat. The dividing cells were noted in paraaortic chromaffin organs, paraganglia, and within the inferior mesenteric ganglion as well. They displayed the morphological character usually associated with their adrenal medullary catecholaminergic counterparts, including numerous dense‐cored vesicles known to be the harbingers of catecholamines and various peptides. Nerve endings were not noticed upon the mitotic cells. The phenomenon of dividing extraadrenal chromaffin cells augments existing data and perhaps suggests that these cells are more endocrine than neural in type and subservient to the adrenal medulla in its classic endocrine function.
The cytoplasmic matrix of the adrenal chromaffin cells of rats under normal and stressed conditions
Authors: Kondo Hisatake 
Published: February 2005

AbstractIn embedment‐free electron microscopy with polyethylene glycol embedding and subsequent deembedding, the conventional cytoplasm of the chromaffin cells was revealed to consist of a three‐dimensional lattice of microtrabeculae and gives the impression that the chromaffin granules are held in place by the lattice. After the restraint stress, a substantial number of chromaffin cells were almost free of granules, and the microtrabecular lattice was much more compact than that in cytoplasmic regions occupied with remaining granules or increased mitochondria. In immunocytochemistry, actin immunofluorescence was confined to the subplasmalemmal regions, while tubulin and tropomyosin immunofluorescence appeared throughout the entire cytoplasm of normal chromaffin cells. After the stress, the immunofluorescence for actin and tubulin increased in intensity, while that for tropomyosin decreased. Immunogold labelings for actin and tubulin were found mainly on the thinner subplasmalemmal microtrabeculae and the thicker perikaryal ones, respectively, while some were deposited in the form of small aggregates on portions of microtrabeculae. No specific association between the gold labelings for actin or tubulin and the chromaffin granules was found, even in the subplasmalemmal regions. A hypothetical interpretation was proposed in which a more compact lattice of the microtrabeculae in spatial association with a looser lattice represents a gelated state of the cytoplasm. The significance of the gel—sol transition of the cytoplasmic matrix in relation to the secretory mechanism was discussed.