bluuebunny/crossref_metadata_2025_split huggingface dataset:
A variation of transmission electron microscope sample preparation for VLSI analysis
Authors: Madden Michael C. , Crafard Penny 
Published: February 2005

AbstractSample preparation for VLSI analysis is often slow due to long ion milling time and because the location of the thin area of the sample is difficult to control. By modifying the standard techniques used with a VCR Group (and perhaps other) mechanical dimpler, the ion milling time can be reduced to less than 30 min. and the location on the thinned area reasonably controlled. These modifications involve the use of a radiused edge on the dimpling tool, a rubber O‐ring on the polishing tool, and not rotating the sample platen during polishing. The modifications to the dimpling and polishing tools allow more control of the geometry of the dimple, while not rotating the sample platen allows a thinner sample to be produced and permits the use of the sample translation micrometers to shift the location of the thinned area during polishing. The quality of samples produced using this modified procedure is equivalent to that obtained with the more standard methods.
An ultrathin sectioning alignment tool with application to cell monolayers
Authors: Cramer Clay T. 
Published: February 2005

AbstractDetails are given concerning the construction and use of a simple tool to help align a specimen block face in the vertical axis for subsequent ultrathin sectioning. Further instructions are given for the preparation of cell monolayers for ultrathin sectioning. The advantage is simple, repetitive and quick alignment of the specimen block face for ultrathin sectioning.
Study of local atomic order in amorphous materials in a computerized transmission electron microscope
Authors: Balossier G. , Garg R. K. , Bonhomme P. , Thomas X. 
Published: February 2005

AbstractExperimental results obtained by electron diffraction (ED) and extended electron energy loss fine structure (EXELFS) techniques to study the local atomic order in amorphous materials such as carbon, silicon, and its oxides are described. Potential applications of ED and EXELFS techniques and their limitations are also discussed.
First stages of crystalzation in a silicate glass: Study by high‐resolution electron microscopy
Authors: Ramos Aline , Gandais Madeleine 
Published: February 2005

AbstractThe first stages of crystallization have been investigated for a glass in the system SiO2‐Al2O3‐Li2O with small amounts of titanium and zirconium as nucleating elements. The studies were performed by electron diffraction and electron microscopy in high‐resolution mode. It has been found that the two phases forming the final glass ceramic crystallize successively. The first one gives small crystallites (<5 nm) randomly dispersed. The lattice plane images in several orientations are in good agreement with TiZrO4 crystal lattice. At 780°C the average crystal size increases with increasing time of the heat treatments from 2.5 nm at 0.5 h to 4.5 nm at 2 h and then remains nearly constant. The crystallization of the second phase, a silicate solid solution with β‐quartz structure, occurs after complete crystallization of TiZrO4.
Direct observation of immunoreactive sites and antibody molecules by ultrahigh‐resolution scanning electron microscope
Authors: Yasuda Kenjiro , Aiso Sadakazu , Nagatani Takashi , Yamada Mitsuhiko 
Published: February 2005

AbstractUsing an ultrahigh‐resolution scanning electron microscope (SEM), an attempt was made to directly visualize antibody molecules at antigenic sites in rat pancreas or on silicone plates. Although individual antibody molecules could not be discerned, a fluffy meshwork, probably indicating several molecules, was seen. With further improvements in specimen preparation, the high‐resolution SEM promises to be an important tool in examining individual antibody‐antigen sites without the need of an electron‐dense label such as colloidal gold.
The research center for ultra‐high voltage electron microscopy at Osaka University
Authors: Fujita Hiroshi 
Published: February 2005

AbstractHigh‐voltage electron microscopy has shown itself advantageous for the study of natural science, including biology, but especially for materials science. The most important advantage for materials science is for in situ experiments about the detailed processes of the phenomena that occur in bulk materials. The present paper is mainly concerned with several types of in situ experiments that have been carried out in the Research Center for Ultra‐High Voltage Electron Microscopy, Osaka University. The following subjects have been studied: (a) fundamental problems, such as the conditions necessary for in situ experiments, functional features of specimen treatment devices, and the effects of electron irradiation; (b) the dislocation behavior of crystals under various conditions; (c) high‐temperature behavior of refractory materials, mainly ceramic composites; (d) new applications of electron irradiation effects, such as amorphization of crystalline materials and electron‐irradiation‐induced foreign‐atom implantation; (e) environment‐matter interaction, mainly chemical amorphization of alloys; and (f) future trends of the in situ experiment, such as combinations with Auger valency electron spectroscopy and high‐resolution electron microscopy.
Studies of refractory carbides, nitrides, and borides as the thermionic emitters for electron microscopy
Authors: Yada Keiji , Masaoka Hideki , Shoji Yutaka , Tanji Takayoshi 
Published: February 2005

AbstractThermionic emission properties of several kinds of refractory carbides, nitrides, and borides of the transition metals in the form of powder were investigated with a newly developed measuring device and evaluated by the figure of merit defined as the ratio of the effective work function to the working temperature at which the vapor pressure becomes 1 × 10−5 Torr. There are several materials whose thermionic emission properties are better than those of tungsten or compatible to those of tungsten among the carbides and borides, such as TaC, HfC, ZrC, LaB6, and CeB6, as judged by the figure of merit. New preparation methods for carburization, nitriding, and boriding of the wires of matrix metals and alloys were successfully developed for using these materials as the cathode of the electron microscope. Other necessary techniques such as spot welding and electrolytic etching were also developed. From the brightness characteristics, it was found that some of carbides, carbide solid solutions, and borides such as HfC, ZrC (Ta0.8–0.7Hf0.2–0.3)C, TaB2, and HfB2 are very good emitters comparable to LaB6. It is emphasized that the work functions of the carbide‐solid solutions (Ta0.8Hf0.2)C and (Ta0.7Hf0.3)C, which have low rates of evaporation at high temperature, show no remarkable rise as compared with that of HfC, so that their figures of merit are better than that of HfC. Feasibility of providing good cathodes with HfC and (Ta0.8Hf0.2)C tips was demonstrated by taking high‐resolution electron micrographs.
Study of temperature factors in cubic crystals by high‐voltage electron diffraction
Authors: Matsumura Syo , Tomokiyo Yoshitsugu , Oki Kensuke 
Published: February 2005

AbstractThe critical voltages for systematic reflections and splits of Kikuchi lines were measured using a high‐voltage electron microscope to investigate the atomic temperature factors in cubic crystals. The split of the Kikuchi line at the intersection with the forbidden 222 Kikuchi line as well as the critical voltage of the 333 reflection for Si and Ge decreased steeply with temperature. The temperature dependence showed that the anharmonic contribution to the atomic‐temperature factor for Si and Ge is extremely weak in the temperature range 300 ∼ 1078 K. On the contrary, the B factors obtained from the measured critical voltages for Al, Cu, and Fe varied nonlinearly with temperature, suggesting the importance of the anharmonic effect in the vibration of atoms. The observed temperature dependence of the critical voltages for the metals were compared with calculations based on harmonic, quasi‐harmonic, and anharmonic approximations. The quasi‐harmonic approximation that takes into account the thermal expansion modification reproduces well the observed values for Fe but not those for Al and Cu. The effect of intrinsic anharmonic vibration should be considered for reproducing the results for Al and Cu. Fitting the measured critical voltages with the calculated ones, we estimated the values for coefficients of the isolated atom potentials. The results are in good agreement with those obtained by neutron and X‐ray diffraction.
High‐resolution transmission electron microscopy of inorganic materials in cellular and topological random systems
Authors: Shiojiri Makoto , Hirota Y. , Isshikim T. , Okashita K. , Sekimoto S. 
Published: February 2005

AbstractThe structure of amorphous Se films, in the topological random system, has been studied by the computer‐simulation, electron diffraction (ED), and high‐resolution transmission electron microscopy (HRTEM). As an example of HRTEM of the cellular random system, our recent investigation on Ba‐ferrites is reviewed beforehand. In HRTEM images of spin‐glass BaTi2–xSnxFe4O11 (x < 0.6), magnetic clusters or clusters of FeO6‐octahedra surrounded by TiO6‐octahedra have been found. The structure of BaSn2Fe4O11 (x = 2) has been determined. The ordering of Sn (Ti) and Fe ions increases with increasing x, which interprets the change from the spin‐glass state to nonspin‐glass state at x = 0.6. It is shown that a cluster of polarized lattice ions is detectable in images of polar‐glass BaxK2–xFexTi6–xO13 (x ≥ 1.2). The structure models of amorphous Se films forming on a substrate have been constructed on a computer, and their radial distribution function (RDF) and HRTEM images have been calculated. Experimental RDF and HRTEM images have been obtained from vacuum‐deposited amorphous Se films and are compared with the calculated ones. It is concluded that in the as‐deposited films most of Se molecules may be composed of Se atoms as small as three and that by the electron‐beam irradiation the molecules link to form spiral chains in amorphous state and then arrange to have the hexagonal crystal structure.
Immunohistochemical distribution and colocalization of regulatory peptides in the carotid body
Authors: Heym Christine , Kummer Wolfgang 
Published: February 2005

AbstractCurrent investigations on the immunohistochemical occurrence and co‐occurrence of biogenic polypeptides in the mammalian carotid body were reviewed and extended by our own recent findings. The family of chromogranins and related peptides in glomus cells appears to have a widespread interspecies distribution, whereas other peptides investigated occur in a species‐specific pattern. Immunoreactivity to antisera against opioids, which derive from the proenkephalin sequence, appears to be present in glomus cells of the rabbit, cat, dog, and a shrew. Conversely, glomus cells of pig and guinea pig predominantly are immunoreactive to cleavage products of prodynorphin, which co‐occur in some cells with substance P and met‐enkephalin‐arg‐phe, respectively. In the rat and Callithrix jacchus, opioid immunoreactivity is present in nerve fibres but not in glomus cells. Immunoreactivity to other peptides, such as neurotensin, cholecystokinin, neuropeptide Y, and galanin, is found only in one or two particular species. Neurotensin immunolabelling occurs in beagle dog glomus cells, which are known to lack substance P. Cholecystokinin immunoreactivity is present in glomus cells of dog and Callithrix, and co‐exists with chromogranin A, neuropeptide Y, and substance P. Substance P appears to exist in both carotid body glomus cells and nerve fibres. Substance P immunoreactivity is present in glomus cells of all species investigated, except dog. Coexistence of substance P and calcitonin gene‐related peptide (CGRP) is demonstrated in nerve fibres of the guinea pig carotid body, which originate in the petrosal and jugular ganglia. Other peptides visualized immunohistochemically in mammalian carotid body nerve fibres are vasoactive intestinal peptide and neuropeptide Y. The functional significance of the various peptides present in the carotid body is discussed.
Electron microscopic localization of enkephalin‐like immunoreactivity in the human adrenal medulla
Authors: Hervonen Antti , Linnoila Ilona , Vaalasti Annikki , Alho Hannu , Pelto‐Huikko Markku 
Published: February 2005

AbstractEnkephalin‐like immunoreactivity in human adrenomedullary cells was studied at the light and electron microscopic levels. Enkephalin immunostaining was associated with chromaffin granules and, in a few cells, with the rough endoplasmic reticulum as well. The relative number of stained granules varied from cell to cell, and a correlation with a particular granular population was not noted. Both large and small granules were labelled. It is concluded that in the human the ability to store enkephalin immunoreactive peptides is a general property of chromaffin granules and, furthermore, is not correlated with specific granular subpopulations or the particular type of catecholamine stored within the cell.
Theory of zone axis electron diffraction
Authors: Bird D. M. 
Published: February 2005

AbstractThe theory of high‐energy electron diffraction is reviewed, with an emphasis on methods that help most in understanding the form of zone axis convergent‐beam patterns. A Bloch wave description is used throughout the paper, and the theory is formulated in real space, leading to general expressions for both zero‐layer and higher‐order Laue zone (HOLZ) diffraction amplitudes. HOLZ diffraction is discussed in detail, and it is shown that first‐order perturbation theory is usually applicable and provides a clear picture of the diffraction. The computation of diffracted intensities is discussed with reference to the many‐beam equations. Diffraction at the [0001] axis in 1T‐VSe2 is analysed both to illustrate the theory and to provide an example of the special effects that occur at well defined string zone axes.
Systematic procedure for indexing HOLZ Lines in convergent beam electron diffraction patterns of cubic crystal
Authors: Fournier Daniel , L'Esperance Gilles , Saint‐Jacques Robert G. 
Published: February 2005

AbstractThis article has been written for experimenters who are beginning to work with convergent beam electron diffraction patterns (CBED). The indexing of the higher‐order Laue zone (HOLZ) lines inside the central spot of a CBED pattern is the first step towards studying variations in lattice parameter and three‐dimensional (3D) symmetry. To index the HOLZ lines one must construct and index the HOLZ, find its interplanar spacing and the location of its projection on the zero order Laüe zone (ZOLZ) for a given zone axis, and finally find the radius of the HOLZ ring. A computer program has been developed to perform all these tasks for cubic crystals and is very useful, especially when one varies parameters such as operating voltage, zone axis, lattice parameter, and crystalline structure.
Composite replicas: Methodologies for direct evaluation of the relationship between intramembrane and extramembrane structures
Authors: Coleman Richard A. , Wade James B. 
Published: February 2005

AbstractElectron microscopic studies of membrane structure have been facilitated by the recent development of the composite replica technique in which the membrane is freeze‐fractured, then inverted and the surface deep‐etched and replicated. Examination in stereo of this composite preparation of two replicas with interposed half‐membrane and associated surface elements reveals the physical relationship between structures on the surface and within the membrane. Composite replicas of the toad urinary bladder surface demonstrated connections of filamentous glycocalyx elements to intramembrane particles (IMPs). Using a bidirectional shadowing technique, many membrane surface particles also are shown to be associated with underlying IMPs, suggesting that these membrane surface particles are projections of the IMPs above the surface of the membrane. There is evidence that elements whose attachment sites relate to the half‐membrane fractured away can be displaced from the membrane surface and lost. Labelling studies using colloidal gold‐labelled antibodies were carried out to assess loss of surface mesh from fractured membrane. Gold distributions and amounts were similar in labelled surface replicas, label‐fracture specimens, and labelled composite replicas, yet the amount of mesh detected in the composite replicas was less than in the surface replicas. This suggests that while some unlabelled or lightly labelled surface elements can be lost from fractured membranes, ligands stabilize elements and reduce their loss apparently by cross‐linking them.
Monolayer freeze‐fracture and scanning tunneling microscopy
Authors: Fisher Knute A. 
Published: February 2005

AbstractThis article reviews research on planar monolayer methods, application of the methods to analyses of transmembrane signaling, and the combination of these methods with scanning tunneling microscopy (STM). Past research has involved the development of monolayer freeze‐fracture methods. These include monolayer freeze‐fracture autoradiography (MONOFARG), an electron microscopic cytochemical method to analyze in‐plane distributions of radioisotopes, and double‐labeled membrane splitting (DBLAMS) and single‐membrane monolayer splitting (SMMS), methods to analyze transmembrane distributions of native and radiolabeled proteins and lipids. Present research has focussed on using these methods to investigate mechanisms of transmembrane signaling mediated by protein kinase C (PKC), including the transbilayer distribution of the tumor promoter TPA, a lipophilic activator of PKC, and the transbilayer distribution of peripheral membrane proteins phosphorylated by PKC. Future work will involve the combination of planar sample preparation with STM. The principles and applications of biological STM are briefly reviewed and a low‐resolution STM image of a planar purple‐membrane monolayer is included. The combination of planar methods and STM can provide the chemical information lacking in STM images enabling microscopists to investigate biochemical phenomena at nanometer resolution.
Surface microanalysis by reflection electron energy‐loss spectroscopy
Authors: Wang Z. L. 
Published: February 2005

AbstractSeveral basic physical concepts of applying eq. Ik = IσNxt to surface microanalysis by reflection electron energy‐loss spectroscopy (REELS) are clarified. Here Ik and I are the integrated intensities of the core ionization edge and the low loss part, σ is the scattering cross section of element x with atomic concentration Nx, and t is the specimen thickness. The reflected inelastic electrons are found to be distributed almost symmetrically around the Bragg sports and can be reasonably described by a Lorentzian function. EELS microanalysis can be performed by using the diffracted sports. The ω correction, arising from the angular contributions of the neighbouring spots into the spectrometer collecting aperture, is required to be considered.
Use of peldri II as a sublimation dehydrant in place of critical‐point drying in fracture‐label cytochemistry and in backscattered electron imaging fracture‐label
Authors: Kan Frederick W. K. 
Published: February 2005

AbstractPeldri II, a fluorocarbon compound solid at room temperature, was used as a sublimation dehydrant in place of critical‐point drying (CPD) in freeze‐fractured cytochemistry. Its applicability to the fracture‐label replica method was demonstrated using freeze‐fractured rat pancreas labeled with Helix pomatia lectin‐gold complex and phospholipase A2‐gold complex for the detection of glycoconjugates and phospholipids, respectively. No difference in morphology and labeling pattern was detected in CPD‐treated and Peldri II‐treated tissue samples. The use of Peldri II was further extended to freeze‐fractured rat duodenum labeled with wheat germ agglutininovomucoid‐gold complex. Again comparable results were obtained when duodenal samples were prepared according either to the conventional CPD method or to the Peldri II sublimation method. Freeze‐fractured replicas of hamster ovaries labeled with Ricinus communis I‐gold complex revealed that Peldri II could also be used as a sublimation dehydrant for preparing tissue samples for examination in the scanning electron microscope by the backscattered electron imaging mode.
Counting cells with stereology: Random versus serial sectioning
Authors: Bertram John F. , Bolender Robert P. 
Published: February 2005

AbstractCounts of cells and nuclei from sections provide information central to studying structural changes in cells, tissues, and organs. This study considers some of the practical problems associated with counting cells with the newer random and serial sectioning methods of stereology and tests the hypothesis that similar cell counts can be obtained with both random and serial sectioning methods.Using irregularly shaped nuclei from alveolar cells of the goat lung, we compared cell counts derived from random (electron microscopic) and serial sectioning (light microscopic) methods. The results showed that both sectioning methods gave similar cell counts (107/cm3 of parenchyma) for type 1 epithelial cells (5.0 vs. 5.0; P=1.0), type 2 epithelial cells (8.6 vs. 9.8; P=0.42) and interstitial cells (34.6 vs. 33.4; P=0.64), provided that corrections were introduced for sectionrelated biases and that the nuclei of the random sectioning method were corrected for shape. We found counting biases of 5%–7% for nuclear shape and 16% for section compression. These observations support the hypothesis that similar cell counts can be obtained with random and serial sectioning, even when nuclei have irregular shapes.
High resolution SE‐I SEM study of enamel crystal morphology
Authors: Apkarian Robert P. , Gutekunst Marc D. , Joy David C. 
Published: February 2005

AbstractUntil recently high resolution TEM was the only imaging mode capable of probing the atomic lattice structure of crystals composing tooth enamel. Studies designed to determine the polyhedral shape of normal enamel crystals and initiation of carious lesions in enamel crystals were hampered and limited by interpretation of two‐dimensional TEM images from thin section and freeze fracture replica specimens lacking depth of field. The newly developed SE‐I signal mode for SEM (SE‐I/SE‐II ratio) can produce images of enamel crystals approaching beam diameter dimensions (0.7–2.0 nm), rivaling the resolution of the TEM technique and generating topographic contrasts for three dimensional imaging at very high magnification (≈︁1,000,000 X). Ultrathin chromium (Cr) films generate enriched high resolution SE‐I contrasts of enamel crystal surfaces and when imaged using an immersion lens field emission SEM operated at high voltage (20–30 KeV) produce unsurpassed topographic contrasts. Since the grain size of Cr is below the resolution of any SEM and is ultrathin (≈︁1 nm), then SE‐I images can provide a more accurate representation of enamel crystal structure than TEM methodologies.Our SE‐I SEM observations of normal human enamel crystals reveal fractured spicules which contain angled flat surfaces delineated by a prominent 2 nm wide SE‐I edge brightness contrast. Although microscopic observations often show crystals which are hexagonal in cross‐section, in both SEM and TEM many other growth habits, including rectangular or irregular crystals (30–40 nm in width) which contain “notches,” are also observed. More detailed morphological studies are therefore required to determine the most likely habit planes and their relevance to the function of the enamel crystals. The granular appearing fine structural contrast imposed onto <100> lattice planes of sectioned enamel in TEM micrographs is also resolved with topographic contrasts in SE‐I micrographs. These granules probably represent one or both of the enamel protein classes.