bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture—Permeation: A technique to assess cytoplasm compactness after glutaraldehyde‐fixation
Authors: Barbosa Maria Luiza F. , da Silva Pedro Pinto
Published: February 2005

We have developed a method—“fracture‐permeation”—to assess the compactness of the cytoplasm in glutaraldehyde‐fixed cells. Cells or tissues are fixed in glutaraldehyde, impregnated with glycerol, and frozen in liquid nitrogen. The cells are freeze‐fractured, thawed, deglycerinated, and immersed in concentrated solutions of globular proteins. In initial experiments, we used native ferritin (NF) to permeate model matrices made of bovine serum albumin (BSA). We show that permeation depends on the concentraion of proteins within the cross‐linked matrix: NF permeates matrices made from 10 or 15% (w/v) BSA solutions but do not permeate matrices made from solutions with 20% (w/v) protein or more. With freeze‐fractured cells, ferritin molecules were unable to permeate the cross‐linked cytoplasm of fungal zoospores and cysts, used here as examples of resting cells. In human lymphocytes from peripheral blood, permeation of ferritin was limited or absent, but it became massive in cells activated by phytohemagglutinin. Massive permeation of ferritin was also observed within the cytoplasmic matrix of other active cells (fungal sporangia, germinating cysts). In the examined resting cells, glutaraldehyde crosslinks the proteins into a dense matrix that effectively excludes ferritin (diameter 12 nm). These findings cannot be explained by models that envisage all cytoplasmic proteins congregated into a single‐phase microtrabecular lattice with the nature and dimensions proposed by Porter and co‐workers. We conclude that compactness of the cytoplasm matrix depends on the physiological state of the cell: It varies through differentiation and is related to the degree of cellular activity.
Postembedment staining of complex carbohydrates: Influence of fixation and embedding procedures
Authors: Thomopoulos G. N. , Schulte B. A. , Spicer S. S.
Published: February 2005

In recent years technological advancements have led to improvements in ultrastructural cytochemical methods for localizing and characterizing complex carbohydrates. In particular the introduction of lectins with specific affinities for various sugars and sugar sequences as histochemical probes has increased knowledge concerning the cellular and subcellular distribution of glycoconjugates. Development of nonepoxy‐based embedding materials has provided increased sensitivity compared to the earlier less specific methods and the current lectin methods for localizing sugar moieties. Postembedment staining based on the reactivity of functional groups present in sugars, such as hydroxyl groups, vicinal diol groups, carboxyl groups, and sulfate esters, requires specific conditions for tissue fixation and embedding. The same requirements pertain to staining based on lectin binding. The influence of fixation and embedment using older and newly developed embedding mixtures on the ultrastructural demonstration of complex carbohydrates is considered in this discussion. Fixation with osmium tetroxide and embedment in epoxy resins provides the least sensitive combination for the detection of the reactive groups of complex carbohydrates. The best ultrastructural demonstration of glycoconjugates is achieved when nonosmicated tissues are embedded in nonepoxy resins.
An inexpensive and highly efficient device for observing a transmitted electron image in SEM
Authors: Oho Eisaku , Sasaki Toshihide , Adachi Koichi , Muranaka Yoshinori , Kanaya Koichi
Published: February 2005

An inexpensive, efficient device that supplies a transmission mode to the conventional SEM has been developed. The transmitted electrons strike a metal plate, and these generate secondary electrons that are proportional to the quantity of the transmitted electrons. The generated electrons are collected by the secondary electron detector. Hence, the performance of this device is influenced by the number of secondary electrons generated in the metal plate. In order to construct a device that can attain the best transmitted electron image, the signal‐to‐noise ratio of images, obtained from various trial devices, were measured by a newly‐developed digital image processing program. When the material and shape of the device are selected, to produce high‐secondary emission, the efficiency of the device compares with that of a relatively expensive standard detector system (scintillator detector).
Calibration of focusing steps and image rotation of electron microscopes
Authors: Hsu Tung
Published: February 2005

Reflection electron microscopy (REM) is used to calibrate the focusing steps and rotation of electron microscopes. The calibration of focusing steps is done by the direct measurement of the shift on in‐focus positions in the REM micrographs. Rotations between the diffraction patterns and images are calibrated in the usual way. By using the REM geometry, the reflection high energy electron diffraction (RHEED) patterns and REM images have no rotation symmetry, thus eliminating the 180° uncertainty.
Removal of epoxy‐attached thin sections from glass slides by plasma etching
Authors: van Deusen Stuart B. , Mackinnon Ian D. R.
Published: February 2005

Thin‐sectioned samples mounted on glass slides with common petrographic epoxies cannot be easily removed (for subsequent ion‐milling) by standard methods such as heating or dissolution in solvents. A method for the removal of such samples using a radio frequency (RF) generated oxygen plasma has been investigated for a number of typical petrographic and ceramic thin sections. Sample integrity and thickness were critical factors that determined the etching rate of adhesive and the survivability of the sample. Several tests were performed on a variety of materials in order to estimate possible heating or oxidation damage from the plasma. Temperatures in the plasma chamber remained below 138°C and weight changes in mineral powders etched for 76 hr were less than ±4%. A crystal of optical grade calcite showed no apparent surface damage after 48 hr of etching. Any damage from the oxygen plasma is apparently confined to the surface of the sample, and is removed during the ion‐milling stage of transmission electron microscopy (TEM) sample preparation.
Real‐space reconstructions of nonideal helical particles
Authors: Bluemke David A. , Carragher Bridget , Potel Michael J. , Josephs Robert
Published: February 2005

We have studied the manner in which real‐space reconstructions of helical particles are affected by particle distortions commonly present in electron micrographs. The effects of image distortions due to noise, nonuniform negative staining, pitch variations, particle tilt, and flattening on the reconstructed cross‐section are difficult to visualize, and therefore we have developed a test system using model images in order to facilitate our investigations. In addition, we have examined the effect of incorrect estimates of the particle repeat length and location of the helical axis on the reconstructed density map. By using models that incorporate defined image distortions, we are able to compare directly reconstructions of the models with those of the idealized structure. This approach can help indicate sources of specimen distortion limiting the resolution of particle reconstructions.
High temperature controlled atmosphere experiments for catalysts in a transmission electron microscope
Authors: Chan Ignatius Y.
Published: February 2005

A new transmission electron microscopy (TEM) specimen preparation procedure for high temperature experiments using a controlled atmosphere specimen holder (HTCASH) has been developed. It is designed for studying the microstructure of catalyst specimens before and after treatments in various gases. The procedure involved (1) finding a new formula for the embedding material, (2) devising a new method of making specimen supports, and (3) developing a method for removing the embedding material after the specimen has been microtomed. These techniques were then brought together to produce the ideal specimens for the HTCASH experiments. As an extra benefit, this procedure is also suitable for preparing specimens for ultrahigh resolution imaging experiments. The application of the new procedure in HTCASH experiments is illustrated through a high temperature reduction of a Co/SiO2‐923 catalyst.
Cyclic X‐Y mechanical tests: A new method to perform in situ reversed‐deformation experiments in the high‐voltage electron microscope
Authors: Kassner Michael E. , Sleeswyk Andre W. , Echer Charles J.
Published: February 2005

There has been, in the past, only limited success with in situ cyclic or reversed plastic deformation tests in the transmission electron microscope (TEM). This is probably partly due to problems associated with buckling of the foil when an applied tensile or shear stress is reversed. Mechanical analysis shows that dislocation movement can be reversed by tensile stressing in alternating perpendicular directions (i.e., 90° rotations of a tensile stress); thus buckling of the foil can be avoided. A design for performing such X‐Y in situ TEM tests is presented, with observations that demonstrate its feasibility.
Quantitative and densitometric considerations in bas‐relief electron micrographs
Authors: Hendricks Gregory M. , Sharp William P.
Published: February 2005

Two methods for bas‐relief electron micrographs are described, one to produce transparencies for projection and one to produce prints for publication. The basis of these methods is a controlled misregistration of a positive image and a negative image, both on film, to increase contrast and produce a “bas‐relief” effect. This gives the final image a three‐dimensional appearance. No apparent loss of resolution results and no artificial amendment is required. To produce transparencies, a contact film positive is produced from the negative and the two are sandwiched in a slide mount with the appropriate amount of lateral displacement to give the effect. To produce prints, the film positive and the film negative are used to sequentially expose the same sheet of photographic paper prior to development to realize the effect. The bas‐relief induced by the misregistration of the film plates causes apparent shadows and highlights that produce the apparent height that is seen in the enhanced images.
Clinical sampling device for rapid viral diagnosis by transmission electron microscopy
Authors: Bozzola John J.
Published: February 2005

A clinical sampling device useful for rapid viral diagnosis was constructed from a plastic‐shafted throat swab by excision of the cotton or alginate wool tip and heat shaping the end of the plastic shaft to accommodate a Formvar‐ and carbon‐coated grid. The device can be conveniently carried in the coat pocket and can be readily used to obtain specimens at the bedside. Various types of fluids containing virus particles may be examined by transmission electron microscopy to obtain a presumptive diagnosis, often in less than 1 hour.
Backscattered electron imaging of immunogold‐labeled and silver‐enhanced microtubules in cultured mammalian cells
Authors: Goode Dennis , Maugel T. K.
Published: February 2005

This technique permits the visualization of microtubules in situ by employing silver‐enhanced immunogold labeling and backscattered electron imagery. For best results, monolayer cultures of PtK2 cells are lysed with Triton X‐100 in a microtubule stabilizing buffer, fixed with 1% glutaraldehyde, reduced with NaBH4, incubated with monoclonal antitubulin and 5‐nm gold‐labeled anti‐IgG, silver enhanced, freeze dried, lightly coated with aluminum, and examined in an SEM equipped with a backscattered electron detector. A high contrast view of the entire microtubule complex of each cell is obtained. Microtubules in freeze‐dried preparations have relatively smooth surfaces, whereas those in critical point dried preparations are more irregular or beaded. At high magnifications, an unstained inner core of each microtubule can be resolved. Backscattered electron imaging appears to be a promising technique for localizing cytoskeletal proteins and other intracellular antigens that can be labeled with immunogold and enhanced with silver.
Multifunctional mini‐computer program providing quantitative and digital X‐ray microanalysis of cryosectioned biological tissue for the inexperienced analyst
Authors: Heyman R. V. , Saubermann A. J.
Published: February 2005

A series of computer programs have been written for use in a multi‐user resource center for biological microanalysis. They are tied together by a “Main Menu” program which acts as a traffic director and guides the investigator into whatever option is desired. These programs have been written with very clear instructions and interaction points. As a result, a complex handbook of options and responses is not required. Consquently, almost no training is required to use these programs as they are essentially self‐explanatory. Extensive error checking has been included so that most errors are identified and corrections are requested without causing a program halt. Options available to the user provide for selected “region” analyses, elementally quantitative image analysis, and sorting of the resulting data files. A complete computer code printout is included in this report.
The conversion of a field‐emission scanning electron microscope to a high‐resolution, high‐performance scanning transmission electron microscope, while maintaining original functions
Authors: Oho Eisaku , Baba Misuzu , Baba Norio , Muranaka Yoshinori , Sasaki Toshihide , Adachi Koichi , Osumi Masako , Kanaya Koichi
Published: February 2005

Recently, the reliability of field‐emission electron guns has increased. In addition, the cost of computer systems for on‐line processing has dropped. Hence, we should now consider the use of scanning transmission electron microscopy (STEM) for routine work, especially, in the field of biology where one may expect to utilize digital image processing techniques.

An STEM has been constructed, without disturbing the original functions, by converting a commercial scanning electron microscope equipped with a fieldemission gun. The STEM is generally operated at accelerating voltage 30 kV, focal length 7.5 mm, and beam current 1−2 × 10−10 A. Several improvements have been incorporated for removing the effects of vibration, contamination, and stray magnetic fields. Also, an adjustable detector aperture was utilized. The modified instrument was connected to an on‐line digital image processing system for utilizing the information obtained from STEM images. The advantages of the modified system were studied from various viewpoints.
Comparison of surface roughness of sections cut by diamond, sapphire, and glass knives
Authors: Mollenhauer Hilton H. , Bradfute O. E.
Published: February 2005

Low‐angle chromium metal shadowing was used to compare the surface roughness of ultrathin sections cut with diamond, sapphire, and glass knives. Surface roughness was less on diamond‐cut and sapphire‐cut sections than on glass‐cut sections, and was greater over tissue than resin, and greatest over red blood cells and mitochondria. Surface roughness contributed to image density variation and thereby lowered contrast and informational content of the sectioned tissue.
Structure of the M Band
Authors: Varriano‐Marston Elizabeth , Franzini‐Armstrong Clara , Haselgrove John C.
Published: February 2005

We have studied the structure of the M band in fish skeletal muscle using thin sectioning and deep‐etching rotary shadowing. A reconstruction of the M band from these images shows it to be formed by obliquely arranged struts, which join the thick filaments to each other. Thickening of the thick filaments' profiles and nodal points where the struts cross each other are responsible for the fine sublines visible in longitudinal sections of the M band region.
Synapses on the mauthner cell of the goldfish: Thin section, freeze‐fracture, and immunocytochemical studies
Authors: Nakajima Yasuko , Tuttle Rebecca , Masuko Sadahiko , Betz Heinrich , Pfeiffer Friedhelm
Published: February 2005

Large myelinated club ending and small‐vesicle bouton synapses on the distal part of the lateral dendrite of the goldfish Mauthner cell were investigated with thin section, freeze‐fracture, and immunocytochemical electron microscopic methods. Large myelinated club endings form mixed synapses, having both gap junctions and chemical synaptic junctions. The correlation of the number of gap junction particles (connexons) and the data from electrophysiological studies of single large myelinated club ending synapses suggest that only a small fraction of gap junction channels are open at any given time during electrical synaptic transmission. The chemical synaptic junctions at the large myelinated club ending synapse have large, round synaptic vesicles, indicating that they are excitatory. This result is in agreement with electrophysiological data demonstrating the excitatory nature of this chemical synapse. Freeze‐fracture of these excitatory chemical synaptic junctions reveals the presence of the intramembrane particle aggregates in the postsynaptic E face.

Small‐vesicle boutons form chemical synaptic junctions with small, flat or oval synaptic vesicles. These structural data, in combination with previous electrophysiological studies, suggest that the small‐vesicle bouton synapses are inhibitory. In support of this theory, the cytoplasmic side of the postsynaptic membrane of some of these synapses show positive immunocytochemical reaction to monoclonal antibodies against the rat glycine receptor. Freeze‐fracture data reveal intramembrane particle aggregates in the postsynaptic P face of some small‐vesicle bouton synapses which could possibly represent glycine receptor aggregates.
Three‐dimensional tomographic reconstruction in high voltage electron microscopy
Authors: Frank J. , McEwen B. F. , Radermacher M. , Turner J. N. , Rieder C. L.
Published: February 2005

The methodology is described, as developed at the Albany NIH Biotechnological High Voltage Electron Microscope Resource, for the three‐dimensional reconstruction of objects in thick sections. The reconstructions are obtained from projection sets which are recorded by high voltage electron microscopy. The different steps of the procedure are illustrated in detail, using the cilium reconstruction as an example.
A systematic approach to the discovery of new proteins of ultrastructural interest
Authors: Singer S. J. , Maher Pamela A. , Cox Gerald F. , Tokuyasu K. T. , Dutton Anne H.
Published: February 2005

A systematic approach to the discovery of new proteins of ultrastructural interest is discussed. It involves the merging of monoclonal antibody technology with immunocytochemical technology, particularly immunoelectron microscopy. In this approach, monoclonal antibodies are raised to a cellular preparation that can be grossly heterogeneous in its protein composition. The hybridoma culture fluids are screened by immunocytochemistry for the ultrastructural localization of their antibodies. Those monoclonal antibodies that show specific ultrastructural localizations of interest are then selected for further investigation. The antigen to which a given monoclonal antibody is directed is then identified by immunoprecipitation and immunoblotting with that antibody. By this approach, two new striated muscle proteins of ultrastructural interest have been discovered and are named zeugmatin and enactin. The former is a protein of over 500 kD localized by immunoelectron microscopy to the Z‐bands, the latter of 245 kD localized to the N1 line of striated muscle.
Loss of square (orthogonal) arrays from cultured airway epithelial cells
Authors: Friend Daniel S.
Published: February 2005

Electron microscopic examination of freeze‐fracture replicas reveals distinctive arrangements and planar distributions of certain membrane constituents. In these replicas, the square (orthogonal) array of 6–7‐nm intramembranous particles is an easily recognizable membrane differentiation commonly observed in transepithelial ion‐transporting epithelia and in several mesenchymal cells, in which they were originally described. Recently, the occurrence, distribution, and number of square arrays have been documented in the lungs of mammals, turtles, and frogs. The current study confirms that there are more than 10 arrays per μm2 basal and lateral portion of the plasma membrane in the alveolar type I and ciliated cells of human, rat, guinea pig, turtle, and frog lung, and in type II pneumocytes of the turtle and frog lung. We have not observed them in mucous cells, brush cells, macrophages, or endothelial cells of any species examined, nor do they appear in the apical portion of the plasma membrane of any airway or alveolar lining cell. Upon elastase or other proteolytic dissociation of the alveolar cells of the mammalian lung, concomitant with breakdown and endocytosis of tight junction strands, the square arrays cluster and are internalized within the membranes of endocytic vesicles that are derived from the lateral and basal portions of the cell. Within 1 day of establishing the cells in tissue culture, tight and gap junctions reappear, but the square arrays do not. Nor do they return to cultures examined on subsequent days. We conclude that the square array is a widespread membrane differentiation throughout the lung and major airways; but extrapolating from results obtained from dog tracheal cells (Widdicombe et al., 1987), the square array configuration of particles is unnecessary for maintaining normal ion transport.
Procedural guide to specimen handling for the ultrastructural pathology service laboratory
Authors: Dvorak Ann M.
Published: February 2005

Transmission electron microscopy serves a useful and often diagnostic purpose in the analysis of human disease. The emerging discipline of ultrastructural pathology serves a much wider field than that of kidney pathology and, of necessity, requires two essential elements. These are (1) the interpretive knowledge which covers all cells in all tissues which compose all organs, their normal substructural composition, and the ultrastructural expression of all of the basic mechanisms of the pathobiology of human disease, and (2) technically excellent preparations of these varied specimens.

In this review, we emphasize the technical aspects necessary for the preparation of these specimens. These include the handling of varied specimens from the time of interruption of blood flow to the sample until fixation, fixation methodology, and routine processing methods for electron microscopy. Specialized techniques that are readily accomplished in an ultrastructural pathology service laboratory are also described. These include methods for the demonstration of glycogen, peroxidase(s), the glycocalyx. We also describe the preparation of permanent, alkaline Giemsa‐stained 1‐μm plastic sections for light microscopic diagnosis, the use of an agar‐pelleting technique to change cell suspensions into readily handled blocks, and the use of Spurr's (J. Ultrastruct. Res. 26:31, 1969) low viscosity embedding for all skin and heavily collagenized specimens.

The diagnostic report for individual samples can routinely be available within 24 hours of specimen arrival in the ultrastructural pathology laboratory with the methods we review here. Examples of these varied samples of human tissues and cells and methods for preparing them are illustrated. We have found such methods useful for diagnostic purposes, e.g., to identify the site of origin of a brain metastasis as the alveolar cell (type II pneumocyte) of the lung, based on the presence of typical lamellar (surfactant) bodies in the metastatic tumor cells (Dvorak and Monahan‐Earley: Norelco Reporter 32:29–36, 1985c), as well as to describe for the first time a new tumor, such as the gut autonomic nerve (GAN) tumor (Walker and Dvorak: Arch. Pathol. Lab. Med. 110:309–316, 1986) or a cell injury process, axonal necrosis, to be characteristic of Crohn's disease (Dvorak et al.: Hum. Pathol. 11:620–634, 1980d; Dvorak and Silen: Ann. Surg. 201:53–63, 1985).
Solutions to difficulties encountered in low‐temperature SEM of some frozen hydrated specimens: Examination of Penicillium nalgiovense cultures
Authors: Allan‐Wojtas Paula , Yang Ann Fook
Published: February 2005

Penicillium nalgiovense cultures, which are used in the food industry, were found to be collapsed when prepared by standard procedures for scanning electron microscopy. Neither freeze‐drying nor critical point‐drying preserved the structure of cultures grown on agar media. Cryofixation and preparation of frozen hydrated samples using the Hexland Cryotrans CT 1000 attachment in conjunction with an AMR 1000A scanning electron microscope yielded micrographs of uncollapsed structures which could be used for morphological characterization. Several additional steps had to be used in sample preparation to achieve satisfactory results. Samples were held in a humid chamber prior to freezing; growth substrate was trimmed as thinly as possible (less than 1 mm above the support); the sides of samples were painted with a conductive cement to their upper edge; and frozen samples were coated intermittently with gold sputtered in several 2‐min bursts.
On the Image‐Contrast Characteristics of Strains, Surface Rugosity, and Defects in Small Metallic Particles
Authors: Pérez R. , Avalos‐Borja M. , Pérez‐Ramírez J. G.
Published: February 2005

An analysis of the effects of strain and surface roughness on the contrast of weak beam images of small metallic particles is carried out. in order to study these effects, theoretical calculations of the intensity obtained in wedge‐shaped bent gold crystals were performed. These calculations were based on the standard form (Bethe's approach) of the dynamical theory. The theoretical results were compared with weak beam experimental images of gold particles. It was found that the image contrast obtained in thin crystalline regions is not sensitive to strain. Therefore, intensity variations experimentally obtained in these regions seem more likely to be related to the surface roughness of the crystalline specimen. We also studied (experimentally and theoretically) the image‐contrast characteristics of stacking faults in small particles. The comparison between the experimental micrographs and the theoretical images suggests a possible model of the small particle shape. This model seems to explain most of the experimentally observed image‐contrast characteristics.
Scanning Optical Microscopy via a Scanning Electron Microscope
Authors: Battistella Florent , Berger Steven , Mackintosh Andrew
Published: February 2005

We have described in detail the principles of operation of a commercially available SEM‐based scanning optical microscope. The stage consists of a cathodoluminescent material which converts the scanning electron beam into a scanning optical beam and an optical system to focus the light beam onto the specimen.

The resolution attainable with such a stage is discussed as well as the efficiency of electron‐to‐photon conversion. Simplified formulae are given and a set of curves plotted which can be used to determine the appropriate tradeoff between resolution and optical power.

Examples of the imaging ability in the optical beam induced current mode from various semiconductor devices are presented.
Visualization of the inner and outer surfaces of the cell membrane and cytoskeleton by polyethylene glycol embedding, subsequent deembedding, and rotary replication with platinum
Authors: Kondo Hisatake
Published: February 2005

Using rotary replication with platinum and carbon to embedment‐free sections of polyethylene glycol (PEG)‐embedded tissue from which PEG had been removed, the membrane specializations on the outer (exoplasmic) and inner (protoplasmic) cell surface as well as the organization of the cytoskeleton was demonstrated. The high quality and excellent preservation were comparable to that obtained by the rapid‐freezing, deep‐etched replica method. The present results indicate that the PEG method is essentially acceptable as a reliable morphological technique. Because either sectioned or replica images from the same tissue cells can be observed simultaneously, the PEG method with rotary replication should provide valuable information on cell ultrastructure.
Electron diffraction structure analysis of phospholipids
Authors: Dorset Douglas L.
Published: February 2005

The use of lamellar electron diffraction data from epitaxially oriented phospholipid crystals for quantitative structure analysis is described in this review of the technique. It is seen that an appropriate correction for crystal texture, which is justified by the analysis of low‐dose lattice images, enables these intensity data to be used much as they would be used in X‐ray crystallography. Analyses of two classes of phospholipids are reviewed, revealing that the recently determined lamellar structures of ether‐linked phosphatidylethanolamine and phosphatidylcholine are quite similar to the acyl‐chain structures. Preliminary analysis of 1,2‐dihexadecyl‐sn‐glycerophospho‐N‐methyl ethanolamine indicates that the headgroup conformation may be similar to that of the ether‐linked lecithin.
Montaging electron micrographs
Authors: Crang Richard E.
Published: February 2005

The preparation of overlapping electron micrographs (particularly from transmission electron microscopy) requires special forethought in planning, exceptional skills in microscopy and photographic techniques, as well as in display preparations which are unique in their handling and execution. In this report, step‐by‐step instructions are given on specimen preparation, micrography, darkroom printing, and mounting for montage display purposes.
The fine structure and morphogenesis of the envelope and nucleocapsid of goat poxvirus and infectious bovine rhinotracheitis virus: A freeze‐fracture study
Authors: Wang Xiao , Ding Mingxiao , Fu Honglan , Wang Mei , Zhai Zhonghe
Published: February 2005

We studied the morphology and morphogenesis of viral envelopes and nucleocapsids of goat poxvirus (GPV) and infectious bovine rhinotracheitis virus (IBRV) by means of the freeze‐fracture technique. The GPV at an early development stage was fractured in its middle, and the envelope was shown to be a bilayer of particles. The mature GPV was fractured between two monolayers of the envelope. These facts suggest that there is little lipid and mainly protein particles in the envelope at the early‐development stage, then the lipid inserts into the envelope during viral development. We found that there were still many intramembranous protein particles in protoplasmic fracture face (PF) and extracellular fracture face (EF) of the envelope of mature GPV in the cytoplasm, and fewer particles in the envelope of released GPV. In the envelope of mature IBRV, however, there were many more intramembrane protein particles in the PF face than that in the EF face. Spike‐like structures could be seen at the outer edge of the IBRV envelope at times. Protein particles were regularly arranged in the plasmic membranes contacting IBRV. This phenomenon seems to be related to IBRV release. The naked cores, empty capsids, and nucleocapsids of IBRV were assembled in the nucleus of infected cells at the same time. The assembled nucleocapsids could be divided into five types according to their different fracturing positions, whose morphology was observed after deep etching. The morphology of the samples prepared with different methods was compared as well.
Electron microscopic study of the morphology and morphogenesis of virus of hemorrhagic fever with renal syndrome
Authors: Chen Dehui , Yang Huibin , Wang Guohua , Zhang Hequi , Ni Dashi , He Hao
Published: February 2005

The morphology and morphogenesis of the virus of hemorrhagic fever with renal syndrome (HFRS) and the associated ultrastructural changes in neurons of the infected mouse brain were examined by electron microscopy. The primary location of the infection in large neurons was in the Golgi apparatus, which had highly proliferated laminar and vesicular profiles. A small number of matured virus particles were found later individually or in small groups within the distended Golgi cisternae and vesicles. Most of the virus particles were round, oval, or elongated and measured about 70–110 nm in diameter. A lipid bilayered viral envelope with an external fringe of surface projections could be resolved at high magnification. The maturation (budding) of the virus occurred exclusively at smooth membrane vesicles, and predominantly at membranes in, or adjacent to, Golgi cisternae. Viral inclusion bodies containing fine filamentous material were seen frequently in close proximity to sites of virus maturation. The known morphological and morphogenetic characteristics of the virus particles observed in infected mouse brain gave further evidence for taxonomic identification of HFRS virus as a member of the family of Bunyaviridae.
Transmission electron microscopy studies of plasma‐etched silicon nitride/silicon carbide composites
Authors: Pink Francis X. , Ostreicher Kim J.
Published: February 2005

Transmission electron microscopy has been used to isolate and examine the intergranular glass phase in hot‐pressed silicon nitride/silicon carbide composites. Previously there have been difficulties in locating a suitable region for studies of this nature because the interfering nitride and carbide grains inhibit isolation of the glass for examination. Radiofrequency plasma etching of thinned sections of 6 wt% Y2O3, 2 wt% A12O3 in Si3N4 containing 30 vol% of SiC proved to be fruitful in isolating the glass phase. A mixture of CF4 and O2 quantitatively remove the acicular nitride phase without any evidence of attack on either the glass or carbide. Composites containing ceria and magnesia as substitutes for yttria behave similarly. This indicates that glasses containing minor to major concentrations of elements forming stable fluorides inhibit the attack of fluoride ions on silica glasses containing these elements.
A computer program for morphometry of circular and elliptical profiles on the microscope
Authors: Núñez‐Durán Harol , Riboni Laura
Published: February 2005

We describe a short computer program, which is written in Pascal language, to measure the diameter of circular and elliptical profiles in sections. Coordinate pairs on the microscope stage, corresponding to two or three points of a profile, are input to obtain its diameter. The program enables one to take measurements directly on the microscope, thereby reducing photographic work and caliper measurement. While the program is largely designed for electron microscopy, it also may be useful for light microscopy morphometry.
Data acquisition system for maximum‐likelihood analysis of electron microscopic autoradiographs
Authors: Fuhrmann Daniel R. , Brown Michael A. , Miller Michael I. , Roysam Badrinath , Saffitz Jeffrey E. , Thomas Lewis J.
Published: February 2005

EMAMAP is a program for the data acquisition phase of maximum‐likelihood analysis of electron microscope autoradiographs. This program is written in C and has been implemented on a Masscomp MC‐500 which supports a graphics processor and a digitizing tablet. The image analysis is automated at a low level: the program operator outlines the edges of the structures of interest using the digitizing tablet, while contiguous regions formed by closed contours are automatically filled by the software. The resulting image is compressed for efficient storage by a quadtree encoding technique for which data compression ratios of greater than 25:1 have been achieved. In practical terms this implies that the data from a typical experiment of 50 autoradiographs could be stored on a single floppy disk. The system is currently in use for acquiring actual biological experimental data.
Structural studies of lanthanide phthalocyanines by high‐resolution electron microscopy
Authors: Zhang W. P. , Kuo K. H.
Published: February 2005

Epitaxial films of lanthanide phthalocyanines (LnPc2H, Ln = Nd, Tb, Er, Tm, Yb, or Lu) formed on a KCl or NaCl crystal have been studied by means of high‐resolution electron microscopy. These complexes are isomorphous and have both tetragonal and base‐centered orthorhombic structures. Though radiation damage makes it difficult to study these beam‐sensitive materials by electron microsocpy, the behaviors of thin film growth and details of structural defects can still be identified at the molecular level.
Computer software for specimen orientation adjustment using double‐tilt or rotation holders
Authors: Chou C. T.
Published: February 2005

Computer software for specimen orientation adjustment relative to the incident electron beam has been developed. The difficulties encountered when tilting severly strained, highly beam‐sensitive, or small‐grain‐size specimens with known structures using either a double‐tilt or a rotation holder in transmission electron miscroscopy (TEM) can be minimized. Combined with computer programs for obtaining the reduced bases from diffraction patterns, the software is also useful for unknown crystals. The algorithm is introduced and examples are given.
Quasicrystals and noncrystallographic symmetry
Authors: Kuo K. H.
Published: February 2005

New findings on quasicrystals with icosahedral, octagonal, decagonal, and dodecagonal symmetries obtained recently in the Beijing Laboratory of Electron Microscopy, Chinese Academy of Sciences, are presented. Special emphasis is put on the relation between quasicrystalline and crystalline structures. The important role played by electron diffraction and high‐resolution electron microscopy in revealing these quasiperiodic structures is pointed out.
Microdiffraction and analysis
Authors: Zhu Jing
Published: February 2005

The intensity distribution in the microdiffraction pattern depends strongly on the coherence of the illuminated source. The coherence width at the specimen level is considered as a parameter to check the coherence of an electron microscope. Two application examples are illustrated. A small interphase precipitate of MgNi2 in an Ni superalloy has been identified by a combination of microdiffraction and energy dispersive spectrum (EDS) techniques, though it can not be found by conventional transmission electron microscopy (TEM) and selected area diffraction (SAD). By means of microdiffraction as well as high‐resolution electron microscopy (HREM) imaging a defect structure has been determined. Such a defect makes the lattice extinction spots appear with various intensities in the selected area diffraction and microdiffraction patterns.
Ultrastructural and paraphenylene studies of degeneration in the primate visual system: Degenerative remnants persist for much longer than expected
Authors: Johnson Betty M. , Sadun Alfredo A.
Published: February 2005

It is a widely held belief that the products of axonal degeneration in the CNS are transitory and are caused by metabolic and phagocytic processes. However, recent light microscopic examinations of human and primate brains using the paraphenylene diamine staining method (PPD), which stains degenerating axons, have confirmed that the products of degeneration persist for years in visual pathways. The routine utilization of the PPD method for delineating human visual pathways requires further confirmation of axonal degeneration. Optic nerves, optic tracts, and lateral geniculate nuclei were collected from human brains that had clinical documentation of optic nerve damage prior to death. Optic nerves, optic tracts, and lateral geniculate nuclei taken from the brains of cynomolgus monkeys that had undergone enucleation 3 months to 1 year prior to sacrifice were also examined. All tissue was processed for electron microscopy; ultrathin sections were cut for electron microscopy, and consecutive sections were cut for light microscopy.

In all cases, the homology of the degenerated processes was confirmed between the light microscopic (PPD) and the electron microscopic sections. Such ultrastructural examination demonstrates that the products of axonal degeneration remain in the primate visual system longer than previously supposed.
A simple device to aid tissue processing of large numbers of blocks for light or electron microscopy
Authors: Smith K. J. , Larramendi P. C. H.
Published: February 2005

A simple device is described that aids the processing of large numbers of tissue blocks for light or electron microscopy. The device has a number of compartments into which different tissue blocks can be placed. Each compartment has a fine mesh floor, allowing the free exchange of the reagents used in tissue processing, and a gentle flow of the reagents is promoted by a magnetic stirring bar, or a rotary mixer. All the materials used are resistant to solvents such as propylene oxide. The device is labor‐saving in that many blocks can be processed as easily as a single block. The device may also be of value in quantitative microscopy, since it ensures that all tissue blocks examined experience an identical processing history.
High Tc ceramic superconductors: Introduction, background, and challenges to the electron microscopist
Authors: Davies Peter K.
Published: February 2005

This introductory article reviews the recent developments in high Tc superconducting ceramics. Particular emphasis is given to the structural and chemical aspects of these compounds that may be of interest to the electron microscopist. Included are some of the contributions made by electron microscopy techniques over the last 10 months. The applications of electron microscopy to solving practical problems associated with these exciting new materials are also discussed.
Structural characterization of Ba2YCu3O7 by high resolution transmission electron microscopy
Authors: Ourmazd A. , Spence J. C. H. , Zuo J. M. , Li C. H.
Published: February 2005

We show that high‐resolution transmission electron microscopy can be used directly to reveal the structure of the metal framework and its defects in Ba2YCu3O7. The use of dynamical effects under carefully selected and controlled conditions allows the detection of long‐range order in the disposition of the oxygen vacancies, but inevitable misalignments make the quantification of the order parameter difficult. Specimen preparation methods are compared, and a wide‐angle convergent‐beam pattern is demonstrated.
Structure of superconducting thin films of YBa2Cu3O7−x grown on SrTiO3 and cubic zirconia
Authors: Tietz L. A. , De Cooman B. C. , Carter C. B. , Lathrop D. K. , Russek S. E. , Buhrman R. A.
Published: February 2005

Thin films of the superconductive oxide YBa2Cu3O7−x have been made by electron‐beam coevaporation of the metals in an oxygen atmosphere onto single‐crystal {001}‐oriented SrTiO3 and yttria‐stabilized zirconia (YSZ) substrates. The oxide films were superconducting in the as‐deposited state (Tc = 81–83K, Jc = 106 A/cm2 at 4.2K). Bright‐field imaging, selectedarea diffraction (SAD), and high‐resolution imaging in the transmission electron microscope were used to characterize the microstructure of these films. All of the films were polycrystalline. On SrTiO3 the films were oriented, for the most part, with {110} parallel to the substrate surface. On YSZ, two microstructures were observed: one with smaller rectangular grains oriented with (100) or (010) parallel to the substrate surface and the other with (001) parallel to the surface (i.e., c‐axis up).
High‐resolution electron microscopy of high‐temperature superconductors
Authors: Marks L. D. , Li D. J. , Shibahara H. , Zhang J. P.
Published: February 2005

We review recent results obtained at Northwestern using high‐resolution electron microscopy to study high‐temperature superconductors. While in general these materials form large, very perfect single crystal grains which display very few imperfections, there is also evidence of slip defects, amorphous regions, and order‐disorder transformations. We also report that the gadolinium‐based superconductors and in one case yttrium‐based superconductors show evidence for some copper solid solubility in the form of copperrich planar defects. The structure of a metastable trigonal polytype is also reported, as are the effects of electron beam and water vapor damage to the materials.
Preliminary study of electron‐energy‐loss spectra of YBa2 Cu3O7−δ
Authors: Batson P. E. , Chisholm M. F.
Published: February 2005

We have obtained the electron‐energy‐loss spectra below 1,000 eV for YBa2Cu3O7−δ. The spectra show contributions from all elemental constituents, although the Y‐signal is very weak owing to its small concentration. The low‐loss region and the Ba‐core losses are very similar to those obtained for BaO. The Cu absorption is similar to that seen in CuO with minor differences relating to Cu concentration and anisotropy. The oxygen 1s absorption has a shape that is quite different from that obtained in CuO and shows striking orientational anisotropy. Radiation damage in the microscope is a problem and leads to changes in the shape of the oxygen edge.
Containment system for the preparation of vitrified‐hydrated virus specimens
Authors: Jeng Tzyy‐Wen , Talmon Yeshayahu , Chiu Wah
Published: February 2005

A guillotine‐type quick freezing device and a bio‐hazard containment box have been designed, constructed, and used to prepare vitrifiedhydrated specimens of viruses in their native environment. Special design considerations include the preservation of the specimen in its natural state in vitrified ice, prevention of virus aerosols escape, and control of the potentially explosive air‐coolant vapor mixtures.
Dynamic hydration effects in an electron microscope cold stage
Authors: Lamvik Michael K. , Davilla Scott D.
Published: February 2005

Water can be a substantial proportion of the residual gas in modern electron microscopes even when frozen hydrated specimens are not used. During measurements of the mass thickness of thin collodion film specimens at low temperatures, it was found that a volatile surface layer (condensed water) modified the apparent rate of mass loss induced by radiation exposure. Mass loss can be enhanced by the presence of water (specimen “etching”), or mass loss can be masked by the dynamic adsorption of water to the specimen surface. The microscope or the grid can be a secondary source of the water; even with cold anticontaminator plates in the vicinity of the specimen, water can be desorbed by x‐rays or backscattered electrons. In one typical situation, the mass loss rate appears reduced (due to water adsorption), but the ultimate damage is greater (due to etching). These results illustrate that care must be taken in interpreting mass thickness measurements made in the presence of water and that the lowest stage temperature does not necessarily produce the best observation conditions for all specimens.
Artifacts introduced by ion milling in Al‐Li‐Cu alloys
Authors: Singh A. K. , Imam M. A. , Sadananda K.
Published: February 2005

Ion milling is commonly used to prepare specimens for observation under transmission electron microscope (TEM). This technique sometimes introduces artifacts in specimens contributing to misleading interpretation of TEM results as observed in the present investigation of Al‐Li‐Cu alloys. This type of alloy, in general, contains several kinds of precipitates, namely δ′ T1, and θ′. It is found that ion milling even for a short time produces drastic changes in the precipitate characterics as compared to standard electropolishing methods of specimen preparation for TEM. Careful analysis of selected area diffraction patterns and micrographs shows that after ion milling δ′ precipitates are very irregular, whereas other precipitates coarsen and they are surrounded by misfit dislocations. In situ hot‐stage TEM experiments were performed to relate the microstructure to that observed in the ion‐milled specimen. Results and causes of ion milling effects on the microstructure are discussed in relation to standard electropolishing techniques and in situ hot‐stage experiment.