bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of olivine single crystals by the micro‐pulling‐down method
Authors: Ganschow S. , Klimm D.
Published: February 2005

Olivine, (Mg1‐xFex)2SiO4, crystals have been grown by the micro‐pulling‐down method. The crystals consisted of a homogeneous core and a surrounding peripheral rim with increased fayalite concentration and numerous second phase inclusions, mainly magnetite. The formation of magnetite could be successfully retarded by using an adapted atmosphere consisting of 5 vol% CO + 10 vol% CO2 + 85 vol% Ar. This mixture yields an oxygen pressure well inside the predominance field of FeO over a wide temperature range. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal growth features and properties of layered rare earth and barium cobaltates
Authors: Bychkov G. L. , Shiryaev S. V. , Soldatov A. G. , Shestak A. S. , Barilo S. N. , Sheptyakov D. V. , Conder K. , Pomjakushina E. , Podlesnyak A. , Furrer A. , Bruetsch R.
Published: February 2005

High quality single crystals of LnBaCo2O5+δ (0 < δ < 1) (Ln = Pr, Eu, Gd, Tb, Dy) with rectangular shape and average dimensions 5 mm × 5 mm × 1 mm were grown for the first time from overstoichiometric flux melt. The data on the primary crystallization field of most cobaltate phases, which appear in parts of corresponding Gibbs triangles in the range 1373 – 1523 K are discussed. Bulk single crystals of new phases HoBaCo4O7 up to 300 mm3, YBaCo4O7 and TbBaCo4O7 up to 10 mm3 in volume were grown first. A solution of these compounds structure has been found in the space group P63mc. For the Ln = Pr, Gd, Sm, Tb, Dy, Ho based systems under the liquidus line there are several other new cobaltate phases of both perovskite, and hexagonal crystal structure. Stability of the double perovskite phase and temperature of the antiferromagnetic – ferromagnetic phase transition in relation to the radius of rare earth ions are compared. The data on the exact analysis of chemical composition, including EDX and iodometric titration, as well as results on magnetic susceptibility of EuBaCo1‐xAlxO5+δ (0 < x < 0.3) are discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, single crystal growth and thermodynamic properties of SrNdAlO4–CaNdAlO4 solid solutions
Authors: Novoselov A. , Ryumin M. , Pushkina G. , Spiridonov F. , Zimina G. , Komissarova L. , Pajaczkowska A.
Published: February 2005

Continuous solid solutions in the SrNdAlO4–CaNdAlO4 system are formed. Powder samples of SrxCa1‐xNdAlO4 (0.0 ≤ x ≤ 1.0) were obtained using the carbonate coprecipitation method while single crystals of SrxCa1‐xNdAlO4 (x = 0.0, 0.162, 0.392, 0.687, 1.0) were grown by the Czochralski method. Structural parameters and thermodynamic properties of the samples were studied by X‐ray diffraction and heat flux Calvet calorimetry. Composition dependence of lattice constants was observed to follow Vegard's low. Heat of solution of the SrxCa1‐xNdAlO4 samples in molten 2PbO·B2O3 were measured, and enthalpies of formation and mixing were calculated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bridgman‐Stockbarger growth and X‐ray photoelectron spectroscopy study of LiY1‐xEuxF4 crystals
Authors: Maślankiewicz P. , Szade J. , Winiarski A. , Daniel Ph.
Published: February 2005

LiY1‐xEuxF4 (x = 0; 0.1 nominally) crystals were obtained by a modified Bridgman‐Stockbarger technique. Europium was found to coexist in the LiYF4:Eu crystal in two valence states, Eu3+ and Eu2+, the content of the latter being enhanced in the near‐to‐surface region. The presence of bulk divalent europium is attributed to a partial reduction of europium during crystal growth. Because of the presence of Eu2+, additional electronic states in the electronic gap of LiYF4 were observed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of ZrN films as substrate masks in liquid phase epitaxial lateral overgrowth of compound semiconductors
Authors: Dobosz D. , Golaszewska K. , Zytkiewicz Z. R. , Kaminska E. , Piotrowska A. , Piotrowski T. T. , Barcz A. , Jakiela R.
Published: February 2005

The usefulness of ZrN films as masks for epitaxial lateral overgrowth of GaAs and GaSb by liquid phase epitaxy is studied. It was observed that during the growth process ZrN masks are mechanically stable, they adhere strongly to the substrate and do not show any signs of degradation even at the growth temperature as high as 750 °C. Moreover, perfect selectivity of GaAs and GaSb epitaxy was obtained on ZrN masked substrates ensuring the growth wide and thin layers. To study the influence of growth conditions on electrical resistivity of the mask, ZrN films deposited on GaAs substrates were annealed in various atmospheres. It was found that at temperatures higher than about 580 °C the ZrN masks become highly resistive when heat‐treated in hydrogen flow employed during growth. Usually, LPE growth temperature for GaAs is higher. Thus, ELO growth of GaAs by LPE becomes more difficult, though still possible, if ZrN masks are to be applied as buried electrical contacts. For GaSb ELO layers however, typical LPE growth temperature is about 480 °C. This allows us to grow high quality GaSb ELO layers by LPE still preserving high electrical conductivity of ZrN mask. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Regenerative and predictive medicine of cardiovascular disease: The 9th Leipziger workshop and the 2nd international workshop on slide based cytometry
Authors: Lenz Dominik , Barten Markus J. , Hiller Sabine , Tárnok Attila , Sack Ulrich
Published: February 2005

Slide‐based cytometry (SBC) and related techniques offer unique tools to perform complex immunophenotyping, thereby enabling diagnostic procedures at very early disease stages. Multicolor or polychromatic analysis of cells by SBC is of special importance, not only as a cytomics technology platform but also for patients with low blood volume such as neonates. The exact knowledge of the location of each cell on the slide allows restaining and subsequent reanalysis of the specimen. These separate measurements of the same specimen can be fused to one data file (merging), thus increasing the information obtained per cell. Relocalization and optical evaluation of the cells, a feature typical of SBC, can be of integral importance for cytometric analysis. Due to this feature, artifacts can be excluded and morphology of measured cells can be documented. Predictive medicine aims at the detection of changes in patient's state before the manifestation of the disease or its complications. Such instances concern multiorgan failure in sepsis or noninfectious posttraumatic shock in intensive care patients or the pretherapeutic identification of high‐risk patients undergoing cancer cytostatic therapy. Early anti‐infectious or antishock therapy and curative chemotherapy in combination with stem cell transplantation may provide better chances of patients' survival at concomitant cost containment. Predictive medicine that guides early individualized decrease or cessation of therapy may lower or abrogate potential therapeutic side effects (individualized medicine). Regenerative medicine concerns patients who have diseased and injured organs and may be treated with transplanted organs. However, there is a severe shortage of donor organs that is worsening yearly given the aging population. Regenerative medicine and tissue engineering apply the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Neovascularization is promoted by bone marrow–derived endothelial progenitor cells that lead to the formation of entirely new vessels into ischemic tissue. With this knowledge, many therapeutical borders can be skipped. Diseases formerly uncontrolled can be corrected with stem cells to provide causal healing with regeneration processes. The 9th Leipziger Workshop combined with the 2nd International Workshop on SBC aimed to offer new methods in image cytometry and SBC for solutions in clinical research. It moved toward practical applications in clinics and the clinical laboratory. This development will be continued in 2005 at the upcoming Leipziger Workshop and the 3rd International Workshop on SBC. © 2005 Wiley‐Liss, Inc.
Passive responses of young guinea pigs during exposure to a novel environment: Influences of social partners and age
Authors: Hennessy Michael B. , Morris Angela
Published: February 2005

Guinea pig pups exhibit a two‐stage, active/passive response during isolation in a novel environment that resembles the “protest” and “despair” stages observed in some species of primates. The present study examined social and developmental influences on the expression of the passive stage of responsiveness in young guinea pigs. Both preweaning and periadolescent guinea pigs displayed the passive stage during isolation in a novel environment. In preweaning pups and periadolescents that had been housed with the mother since birth, the presence of the mother in the novel environment prevented the passive stage from occurring. Levels of passive responses in the presence of an unfamiliar adult female were generally intermediate to those in the other two test conditions; however, periadolescents housed only with a peer between weaning and testing exhibited the passive stage of responsiveness not only when alone but also when with the mother or an unfamiliar female. The findings indicate that the passive responses can occur in periadolescent guinea pigs and that the test conditions under which they occur depend upon the periadolescents' social housing conditions prior to testing. Further, the results are consistent with the hypothesis that responses during the second stage constitute “stress‐induced sickness behaviors.” © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 86–96, 2005.
Cardiac reactivity is associated with changes in negative emotion in 24‐month‐olds
Authors: Buss Kristin A. , Hill Goldsmith H. , Davidson Richard J.
Published: February 2005

Despite the call for multilevel observation of negative affect, including multiple physiological systems, too little empirical research has been conducted in infants and young children, and physiology–affect associations are not consistently reported. We examined changes in heart rate, respiratory sinus arrhythmia, and preejection period in 24‐month‐olds across four increasingly challenging, emotion‐eliciting tasks. We predicted that changes in cardiac reactivity would be systematically related to changes in negative affect. Results largely support the predictions with one important exception. With increasing distress across the tasks, HR increased and RSA decreased. However, no significant changes in PEP were observed. HR was associated with negative affect during all tasks, and changes in HR were related to changes in negative affect. PEP and negative affect were associated, but only marginally so. Within‐subject analyses confirmed the predicted associations. Finally, the associations between physiology and negative affect were different for boys and girls. We discuss these results in the context of implications for future research on cardiac–affect associations in young children. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 46: 118–132, 2005.
Mild Protocols for Generating Molecular Complexity: A Comparative Study of Hetero‐Domino Reactions Based on the Oxidant and the Substitution Pattern
Authors: Candela Lena José I. , Sánchez Fernández Elena M. , Ramani Alwar , Birlirakis Nicolas , Barrero Alejandro F. , Arseniyadis Siméon
Published: February 2005

A bicyclic unsaturated 1,2‐diol framework was found to undergo an interesting set of domino reactions on treatment with oxidants. One‐pot syntheses of seven‐membered‐ring‐containing frameworks were achieved by a Pb(OAc)4‐mediated domino process, while with other oxidants investigated, such as Mn(OAc)3, Dess–Martin periodinane, PhI(OAc)2, Ph3Bi(CO)3, NaIO4, and NaBiO3, the domino process was interrupted halfway through. Finally, tetrapropylammonium perruthenate (TPAP‐NMO), Pd(OAc)2, pyridinium dichromate (PDC), and pyridinium chlorochromate (PCC) gave only allylic oxidation and further diketone formation without any of the bond cleavage that is necessary to initiate the domino process. The substrates were chosen to test the limits of reactivity of various unsaturated 1,2‐diol derivatives and to provide guidelines for their use in constructing complex synthetic targets. In this article we provide details of the reaction conditions, preparation of the starting materials and characterization of the products, along with new, unpublished results. Information is assembled to facilitate comparison between the various oxidants, solvents and substitution patterns. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Flow Injection Analysis of Mixtures of Dopamine, Adrenaline and Ephedrine in Human Biofluids Using Stabilized after Storage in Air Lipid Membranes with a Novel Incorporated Resorcin[4]arene Receptor
Authors: Nikolelis Dimitrios P. , Siontorou Christina G. , Theoharis George , Bitter István
Published: February 2005

This work describes a technique for the rapid, selective and sensitive electrochemical flow injection analysis of mixtures of the stimulating compounds adrenaline, dopamine, and ephedrine using stabilized after storage in air bilayer lipid membranes (BLMs) with incorporated resorcin[4]arene receptor. Injections of the stimulating compounds were made into flowing streams of a carrier electrolyte solution and a transient current signal, with duration of seconds, reproducibly appeared in less than two min after exposure of the lipid membranes to the compounds. The magnitude of this signal was linearly related to the concentration of the compound, which could be determined at micromolar levels. Repetitive cycles of injection of stimulating compounds have shown no signal degradation during each cycle (30 sequential injections). The time of appearance of the transient response was different for each stimulating compound and increased in the order of adrenaline, dopamine and ephedrine. The difference in time of response has allowed selective detection and analysis of these compounds in mixtures. The investigation of the effect of potent interferences included a wide range of compounds usually found in human biofluids, as well as proteins and lipids. The results showed that only proteins (most common in lipid film based biosensors) pose a problem that can be eliminated by modulation of the carrier solution to flow rates that do not allow adsorption of these compounds in the lipid films. The technique was applied in human urine samples.
Application of a Carbon Paste Electrode Modified with a Schiff Base Ligand to Mercury Speciation in Water
Authors: Colilla Montserrat , Mendiola M. Antonia , Procopio Jesús R. , Sevilla M. Teresa
Published: February 2005

A carbon paste electrode, modified with benzylbisthiosemicarbazone is used for mercury speciation in water samples. Mercury ion is selectively accumulated on the electrode surface at open circuit and its analysis was performed by cyclic voltammetry or square‐wave voltammetry (SWV). A detection limit of 8 μg L−1 (3σ) was found for 15 min of accumulation using SWV as measurement technique. The effect of several metallic ions and organic substances on voltammetric signal is examined. For speciation purposes, a ligand competition methodology between ligands in solution and electrode is used. Model mercury complexes are characterized as a function of their dissociation kinetics. The method was applied to mercury speciation in water samples from the Jarama River in Madrid.
Sarbanes‐Oxley: Will you need a forensic accountant?
Authors: Christensen Jo Ann , Byington J. Ralph , Blalock Tonya J.
Published: February 2005

The Sarbanes‐Oxley Act forces top management to certify that financial statements are free of fraud and material misstatement. Just using an independent auditor may not be enough. The authors explain why adding a forensic accountant to an audit team is an advantage—and might have saved the careers of some high‐profile cor‐porate executives. © 2005 Wiley Periodicals, Inc.
STEM imaging of thick specimens with off‐axis detectors
Authors: Cowley J. M.
Published: February 2005

For scanning transmission electron microscopy (STEM) images obtained with relatively small objective aperture sizes, the contrast of small objects contained within thick specimens may be considerably enhanced by using an off‐axis detector aperture situated on the edge of the central beam spot. The effect is demonstrated for both crystalline and amorphous specimens. The effect arises because the detector collects part of the small angle inelastic scattering and is modified by refraction effects for specimens of rapidly changing thickness.
Computer simulation and analysis of high‐resolution electron microscope images and diffraction patterns with partial coherence, hollow cone illumination, and virtual apertures
Authors: Krakow William
Published: February 2005

A general method for computing high‐resolution conventional transmission electron microscope images and diffraction patterns, when there are different types of partially coherent illumination conditions, is described. Examples of convergent beam, hollow cone, and virtual aperture illumination conditions are given in the context of interpreting image features. A comparison of real and computed diffraction patterns shows that, in practice, many innovative imaging modes are possible, which can be verified prior to real microscope experiments.
Rapid freezing, cryosectioning, and x‐ray microanalysis on cardiac muscle preparations in defined functional states
Authors: Wendt‐Gallitelli Maria‐Fiora , Wolburg Hartwig
Published: February 2005

Electrically stimulated heart muscle preparations can be quickly frozen in undercooled propane at defined times of the mechanically controlled contraction cycle. The apparatus for triggered freezing of the muscle strips in undercooled propane is described in detail. Freeze substitution of some strips after freezing shows the degree of ice crystal formation without the potential interference of artifacts introduced later by cryosectioning and freeze drying. Ultrathin longitudinal and transversal cryosections are cut with a LKB cryoultramicrotome at temperatures of −130 to −140°C, freeze‐dried at 10−6 Torr vacuum and carbon‐coated before analysis. The freeze‐dried cryosections are analyzed in a Siemens Elmiskop 102 electron microscope equipped with a Kevex energy dispersive system, and the elemental concentrations (in mMol/kg d.w.) of Na, Mg, P, S, Cl, K, and Ca are determined in subcellular compartments of muscle frozen in different functional states. The methodology of quantitation, i.e, determination of elemental net peak and continuum, correction of continuum, preparation of standards, and deconvolution of overlapping peaks are described. The minimum detectable elemental concentration using the reported methods is in the range of a few mMol/kg d.w. This also applies to Ca, which can be accumulated in heart muscle in readily detectable amounts in intracellularly located stores as well as structures connected with the cell membrane. The present report shows that cryotechniques and x‐ray microanalysis can be successfully applied to heart physiology.
The preparation of cultured cells of vascular origin for transmission electron microscopy
Authors: Purdy‐Ramos Susan I. , Forbes M. S.
Published: February 2005

A method is described for obtaining optimal, reproducible ultrastructure of vascular smooth muscle cells and vascular endothelial cells in culture. Routinely grown cultures are prepared for TEM with a precise regimen of fixation, postfixation, en bloc staining, dehydration, and embedment. The most important aspects of this procedure are the following: (1) fixation with a percentage‐gradient series of glutaraldehyde solutions at 37°C, (2) immediate postfixation with osmium tetroxide solution, and (3) block‐staining with uranyl acetate solution to eliminate any extraction of constituents during subsequent processing.
Surface‐replica cytochemistry as a tool for studying cell‐surface enzyme activity: Membrane ecto‐ATPase localization in liver cell cultures
Authors: Karasaki Shuichi , Tanaka Akira
Published: February 2005

A stain‐replica technique is described for cytochemical examination of ecto‐adenosine triphosphatase (ATPase) activity over the membrane surface of monolayer cell cultures. Rat liver epithelial cells grown on a plastic substrate were fixed in glutaraldehyde, incubated in situ in an ATPase‐lead reaction medium, ethanol‐dehydrated and air‐dried. The cell surface of the monolayer cultures was replicated with plasma polymerization of hydrocarbon gas in the negative phase of glow discharge. X‐ray microprobe analysis confirmed the site‐specific deposition of lead phosphate in the polymer‐replica films. The cytochemical localization of lead was mirrored in the replicas of epithelial cells, demonstrating that ATPase activity was expressed along the apical margins of cell‐to‐cell contacts. Little or no activity was present over the remainder of the smooth‐surface membranes. In transformed epithelial cells, there were abundant reaction products over the microvilli and intercellular boundaries. These observations were consistent with biochemical data on the liver epithelial cells in culture and suggested the potential of surface‐replica cytochemistry.
Preparation of biological tissue sections for correlative ion, electron, and light microscopy
Authors: Kupke K. G. , Pickett J. P. , Ingram P. , Griffis D. P. , Linton R. W. , Burger P. C. , Shelburne J. D.
Published: February 2005

In order to correctly interpret the chemical images obtained using ion microscopy (IM), it is useful to correlate them with the information provided by conventional light microscopy (LM), secondary electron imaging (SEI), backscattered electron imaging (BEI), and electron probe microanalysis (EPMA). Accordingly, we have devised a technique of specimen preparation which allows for the application of several different microanalytical techniques to a single histologic section mounted on the same substrate. Sections are cut onto polyester plastic coverslips (devoid of peaks for any element with atomic number > 9 using EPMA) and studied by LM. After a light rotary coating with carbon (to prevent charging), the section can then be examined by SEI, BEI, and EPMA. Specific areas can be marked for IM study either with an objective‐mounted pin tissue microlocater, or by placing small pieces of metal foil, cut in specific geometric shapes, over features of interest. After sputter‐coating the sample with platinum, metal‐free shadows are visible using a low‐power reflected light microscope available on a typical IM sample chamber as a guide for ion beam placement. The conductive coatings also minimize specimen charging during IM. Post‐IM light microscopy, SEI, and BEI are used to confirm the location of specific areas probed in the IM experiments and to provide information on differential ion‐sputtering artifacts and tissue contaminants. This new correlative technique should permit better understanding of the images obtained with these diverse instruments.
Localization of opioid binding sites in rat brain by electron microscopic radioautography
Authors: Hamel Edith , Beaudet Alain
Published: February 2005

Two met‐enkephalin analogs (FK 33–824 and FW 34–569, Sandoz) were utilized for in vitro labeling of opioid binding sites in the rat central nervous system. Binding kinetics determined in 20‐μm‐thick frozen tissue sections of the striatum revealed that both pentapeptides bind to a single population of sites at 20°C with an apparent dissociation constant (KD) of approximately 1–2 nM and a maximum capacity (B max) of 65–170 fmoles/mg protein. Radioautographic data suggest that this population is the same for iodinated and tritiated forms of the FK compound and the iodinated FW analog. Fixation of labeled sections with high concentrations of glutaraldehyde allowed proportional retention of more than 50% of specifically bound 125I‐FK molecules in all brain regions after histological processing for high‐resolution radioautography. In contrast, glutaraldehyde fixation did not prevent the loss of bound 125I‐FW molecules. These differences are attributed to the presence in FK, but not in FW molecules, of a free primary amino group considered essential for cross‐link formation between aldehydes and proteins, and imply that a majority of FK‐receptor complexes may be stabilized by glutaraldehyde. Consistent with this observation is the fact that the radioautographic distribution of specifically bound 125I‐FK was unchanged after fixation and dehydration. In electron microscopic radioautographs prepared from prefixed, vibratome‐cut striatal sections that were incubated with 125I‐FK and fixed with glutaraldehyde, silver grains were found to be mostly associated with neuronal plasma membrane interfaces. The present methodological approach thus appears to be compatible with electron microscopic localization of opioid binding sites in the central nervous system and might be applicable to the localization of other types of binding sites using radioligand molecules that contain a free primary amino group.
Scanning electron microscopy of vascular casts
Authors: Burger Peter C. , Chandler David B. , Klintworth Gordon K.
Published: February 2005

Corrosion casts provide three dimensional replicas that can be examined readily by scanning electron microscopy (SEM). They are prepared by filling vascular networks with polymerizing plastic and then digesting away the tissue. As based on our studies of ocular vessels, this report describes the vascular anatomy, as well as the artifacts, that are encountered during SEM studies of such preparations.
Enzyme‐gold electron microscopic cytochemistry: A new affinity approach for the ultrastructural localization of macromolecules
Authors: Bendayan Moïse
Published: February 2005

The enzyme‐gold postembedding approach has been introduced recently in the field of cytochemistry for the ultrastructural localization of macromolecules. This technique is based on the affinity properties existing between an enzyme and its substrate. The possibility of detecting substrate molecules by applying enzyme‐gold complexes has been established. The present review deals with the development and the technical approach of this method. Various applications are reported for the demonstration of the reliability of the technique that yields results of high specificity and resolution. In addition, some technical problems and limitations particular to this method are reported and discussed.
Electron microscopy of semithick sections: Advantages for biomedical research
Authors: Rieder Conly L. , Rupp Gerald , Bowser Samuel S.
Published: February 2005

Many transmission electron microscopes are available which can be used to examine biological material in 0.25–0.50‐μm‐thick sections. When compared to the traditional thin section, these “semithick” sections possess a number of inherent advantages: They can be screened for content with the phase contrast light microscope, they facilitate many types of studies requiring an analysis of serial sections, and they are frequently the optimum thickness for stereomicroscopy. Structures such as microtubule‐associated components, as well as structural relationships between cellular constituents, may also be clearly visible in semithick sections which are not visible, or go unnoticed, in thin sections. Together these advantages enable an investigator to obtain a more complete three‐dimensional picture of a cell or cell component in a significantly (i.e., up to 90%) shorter period of time than would be required if thin sections were used. Semithick sections may, therefore, make a study feasible which is not approachable, or which is approachable only with great difficulty, by conventional thin sectioning techniques.
Preparation of carbon films from evaporated fibers and rods at fore‐vacuum pressure
Authors: Namork Ellen
Published: February 2005

Fore‐vacuum (pressure ≥ 3 Pa) evaporation of carbon fibers and rods to thin films has been tested and the resulting thicknesses recorded. A modified sputter coater was used as a vacuum evaporator. The quality of the carbon films was evaluated by bright‐field and dark‐field electron microscopy. Although high‐vacuum‐evaporated carbon films are superior in quality, low‐vacuum‐evaporated carbon films were found fully acceptable for routine work in bright field, for both TEM and SEM purposes. Apart from being time‐saving, the method presented has the obvious advantage, in SEM preparations, that carbon coating and metal sputtering can be carried out in the same unit without breaking the vacuum.
An application of rapid freezing, freeze substitution–fixation for scanning electron microscopy
Authors: Osatake Hitoshi , Tanaka Keiichi , Inoué Takao
Published: February 2005

A combined technique of the rapid freezing, freeze substitution–fixation method and the osmium–DMSO‐osmium method was devised. By this combined method we clearly observed the architecture of intracellular components in three dimensions. Morphological characteristics were generally similar to those of tissue prepared by the osmium–DMSO‐osmium method but different in some respects. Mucigen droplets in intestinal goblet cells, for example, appeared as separated spheres, while in specimens prepared by chemical fixation they were observed as a mass of fused droplets. In the Golgi complex, all cisternae were extremely flat, although they usually dilated on the cis side after chemical fixation. Particles on the mitochondrial tubules of liver cells were well distinguished. They were mushroom shaped, as are those observed by negative staining. The combined method, that is, the rapid freezing, osmium–DMSO‐osmium method, is thought to be effective for studying the true structure of intracellular components by scanning electron microscopy.
A method of noise removal using the inverse transform of an image autocorrelation function
Authors: Baba Norio , Oho Eisaku , Kanaya Koichi
Published: February 2005

A method for a reversible transform between an image and image autocorrelation function has been devised, and it has been applied to the reduction of random noise in a microscope image. Object‐related features of an image signal as well as noise features are overlapped at the vicinity of the origin of an image autocorrelation, and a peak is formed at this position. The present method removes the noise contribution in this peak and returns the autocorrelation function, thus corrected, to the image. An autocorrelation function is computed by two Fourier transforms as based on the convolution theorem. The inverse transform from the image autocorrelation function is made possible by performing two Fourier transforms in reverse to the above. This method has been developed to remove random noise more accurately from a single image (especially for nonperiodic images) than other image‐processing methods such as smoothing techniques and low pass filtering.
Quantitative EDS and WDS X‐ray microanalysis of semiconductor materials: Principles and comparisons
Authors: Herrington Charles R.
Published: February 2005

The basic principles and procedures for performing accurate X‐ray microanalyses on semiconductor materials as well as the differences and advantages of EDS (energy‐dispersive spectroscopy) and WDS (wavelength‐dispersive spectroscopy) are presented. Many of the techniques discussed are the result of extensive experience with some photovoltaic materials such as CuInSe2, GaAs, CdTe, CdS, CdSnP, InP, ZnP, and amorphous Si‐based alloys.

Results of an experiment designed to compare the performance of an energy‐dispersive X‐ray spectrometer (EDS) and a wavelength‐dispersive X‐ray spectrometer (WDS) on some semiconductor materials are presented. CdTe, CdSe, CuInSe2, ZnSe, and InSb standards were used to measure the k‐ratios with pure element standards employing both types of X‐ray spectrometers to demonstrate the ability of each to measure elemental compositions under various operating conditions. Both types of spectrometers were utilized on a Cameca MBX electron microprobe at identical X‐ray take‐off angles.

The EDS spectrometer was found to perform equal to the WDS spectrometer when integral peak‐to‐background ratios were greater than seven, when the X‐ray line being measured was greater than about 1,000 eV, and when adjacent peaks were separated by more than three times the detector energy resolution.
A computer program for the systematic sampling of sections in microscopic morphometry
Authors: Núñez‐Durán Harol
Published: February 2005

A computer program is described that facilitates systematic and unbiased sampling in morphometry. Input data are coordinates of the four corners of a section as displayed in the position indicators of the microscope stage. Outputs are coordinate values in the form of a regular lattice that describes where to place the stage and perform the sampling on the section. In addition, some other data are provided by the program, such as total area of section, length of sides, etc. The program is written in BASIC but can be easily converted to other computer languages.
Electron‐beam‐induced current decay measurements in electron probe instruments using a multichannel analyzer
Authors: Yacobi B. G. , Herrington C. R.
Published: February 2005

A simple method for decay measurements of the charge collection mode (commonly referred to as electron‐beam‐induced current or EBIC) of an electron probe instrument is presented. The decay, which occurs at continuous electron irradiation, should be distinguished from a decay measurement due to the electron beam blanking. This method could be applied to other modes of an electron probe instrument, e.g., cathodoluminescence, in studying electron‐beam‐sensitive semiconductors. An example of the decay of the EBIC signal in a hydrogenated amorphous silicon device is presented.
Construction and application of a 400 kV analytical atom resolution electron microscope
Authors: Hashimoto Hatsujiro , Endoh Hisamitsu , Tomita Masato , Ajika Natsuo , Kuwabara Masago , Hata Yoshifumi , Tsubokawa Yoshiyuki , Honda Toshikazu , Harada Yoshiyasu , Sakurai Shigekata , Etoh Terukazu , Yokota Yasuhiro
Published: February 2005

The factors defining the resolution limit and the conditions for obtaining images at atomic resolutions are briefly discussed. The construction and performance of a 400 kV analytical atom resolution electron microscope (AARM), and the functions of an energy selecting microscope, X‐ray micro‐analysis, and on‐line image processing systems are described. Some examples of applications of the AARM are shown.
A sorting and searching computer program to index electron diffraction patterns from crystals of low symmetry
Authors: Narayan C.
Published: February 2005

Electron diffraction patterns generated from phases that have low crystallographic symmetry are difficult and tedious to analyze by conventional techniques. This paper describes a computation scheme that can index electron diffraction patterns efficiently and quickly and be easily implemented on a personal computer. The technique is based on sorting and searching and is especially useful when rapid analyses of electron diffraction patterns are necessary and the crystalline phase under study has a low symmetry.
A simple method for quick‐freezing
Authors: Bearer Elaine L. , Orci Lelio
Published: February 2005

In conventional freeze‐fracture replicas produced from tissue cryoprotected with glycerol, the hydrophobic inner surfaces of membranes are revealed, but hydrophillic structures are obscured in the surrounding ice. Quick‐freezing of tissue obviates the need for glycerol, which prevents the removal of this ice by etching or freeze‐drying, but the major problem in freezing without glycerol cryoprotection is ice crystal formation. We describe here a simple method for quick‐freezing tissue, in the absence of glycerol, on a nitrogen‐cooled copper block with a hand‐held specimen holder. This method freezes samples well enough to preserve molecular detail that can be revealed by subsequent etching. We show some examples of the quality of this freezing with respect to the visualization of molecular detail in isolated protein molecules such as ferritin and catalase. Furthermore, we show examples of in situ cellular structures that are revealed by this method, and we compare the structure seen in these replicas with structures preserved by quick‐freezing at liquid helium temperatures.
Cryo preparation of isolated rabbit pancreatic islets
Authors: Sato Tamiko , Herman Lawrence
Published: February 2005

A Flotronic silver membrane has been used as a vehicle to process, via freeze substitution, collagenase‐derived rabbit pancreatic islets. The procedure provides: (1) a simple, inexpensive method for handling larger numbers of tightly clustered islet aggregates; (2) a metal surface for rapid heat transfer from specimen to cryogen resulting in an increased circumferential zone of fine structural preservation; (3) the elimination of possible artifacts associated with impact or rotation of biological specimens against a cooled, highly polished metal block; (4) superior preservation of structural components not usually observed by conventional modes of fixation; (5) retention of metabolic components which may subsequently be available for immunocytochemical or X‐ray energy dispersive procedures.
Cathodoluminescence attachment to an electron probe instrument
Authors: Yacobi B. G. , Herrington C. R.
Published: February 2005

A simple cathodoluminescence (CL) attachment to a JEOL JSM‐840 scanning electron microscope (SEM) is described. It is based on a Si photodiode mounted inside the SEM chamber. The current amplifier of a backscattered electron detector unit, which is a standard feature of this SEM, is used to amplify and display the CL images. Examples of CL panchromatic (integral) images of GaAs, InP, and ZnS crystals are presented.
Detection of sulfur in fixed and embedded rat peritoneal mast cell granules by X‐ray energy dispersive spectroscopy
Authors: Caulfield John P. , Hein Ann , Tsunoda Kin‐Ichi , Shapiro Robert
Published: February 2005

Purified rat peritoneal mast cells contained 3.3 × 10−5 gm SO4 and 2.2 × 10−8 gm Ca/106 cells. The molar ratio of S/Ca in the whole cell was 600:1. Frozen thin sections of unfixed mast cells contained only sulfur (S) in the granules when examined by X‐ray energy dispersive spectroscopy (EDS). Mast cells fixed in 3% glutaraldehyde and 1.5% formaldehyde in 75% ethanol (Et/Ald) or in mixed buffered aldehydes and embedded in Epon 812 or the low viscosity resin diepoxyoctane (DEO) contained S in all granules and Ca in some of the granules measured. Neither element was found in the nucleus, cytoplasm, or resin. Isolated, Et/Ald fixed and embedded granules also contained S. The presence of Ca in the granules was artifactual in that the Ca was absorbed from water in the trough of the diamond knife and/or from the filter paper used to blot the sections dry. This phenomenon was investigated further. Sections of Et/Ald fixed and embedded mast cells were incubated with 5 × 10−6 to 10−2 M CaCl2. Ca was detectable in 100% of the granules incubated at concentrations ≥ 10−4 M and reached a constant S/Ca ratio of 2.0 at concentrations ≥ 10−3 M. Ca was not detectable in the nucleus, cytoplasm, or resin at 10−2 M. A plot of S versus Ca counts from the granules of cells incubated with 10−2 M CaCl2 was linear with a slope of 2.0 and a correlation coefficient of 0.88. Et/Ald fixed cells incubated with distilled H2O had fewer granules containing Ca, 10%, than unincubated cells, 77%. Further, H2O removed all Ca from Et/Ald fixed cells embedded in DEO. These studies show that S, which is present as SO4 on the proteoglycan heparin, is readily detectable by X‐ray EDS in fixed and embedded cells. An artifact of the technique is that weak anionic sites, which are most probably carboxyl groups on the proteoglycan, can bind the divalent cation Ca and cause spurious localization.
A comparison of on‐line digital recording with conventional photographic recording for scanning electron microscopy
Authors: Oho Eisaku , Sasaki Toshihide , Kanaya Koichi
Published: February 2005

The scanning electron microscope (SEM) has previously utilized a video monitor plus camera as the image recording system. However, this conventional method is inefficient in relation to information present in the original electric signal. Therefore, we propose, for general use, an on‐line recording system consisting of an A‐D converter, image memory, and computer. In addition, we found that the effect of vibration in the SEM image could be reduced by application of the digital recording system. In the present study, interpolation and signal averaging programs were utilized for confirming the performance level of the on‐line recording system. These programs were found to be very effective for SEM.
Quantitative analysis of synapse structure with a semiautomatic interactive computer system: A study on identified pyramidal tract neurons in the sensory‐motor cortex of cat
Authors: Saito Kiichiro , Niki Kazuhisa , Eins Siegfried , Wolff Joachim R.
Published: February 2005

Pyramidal tract (Pt) neurons in the sensory‐motor cortex of cat were labeled by injection of HRP into the spinal cord. Ultrastructural and quantitative analysis of the synaptic covering of their soma and apical dendrite (up to 100 μm from soma) was undertaken. We intercalated a visual‐manual treatment between composite electron micrographs and a fully automated computer system and developed specific programs for evaluation of the morphometric data. Programs are included. A total of 412 synaptic boutons were examined that were found in contact with large Pt neurons. The mean linear percentage of the surface area covered by boutons was 26.2 ± 8.4% and the mean contacting length and cross‐sectional area of the bouton profiles were 1.28 ± 0.58 μm and 0.89 ± 0.59 μm2, respectively. All types of boutons with active zones accounted for 41.2% of the total. The distribution of two types of bouton (S‐ and F‐type boutons, showing asymmetric and symmetric contacts, respectively) was examined quantitatively. The mean proportion of F‐type boutons was 89.1% with a soma and S‐type boutons contacting apical dendrites was 10.9%. In addition, GABAergic boutons were identified with the soma by immunocytochemistry with antibodies against glutamic acid decarboxylase. They formed symmetric synaptic contacts with the Pt cells that were identical to those formed by F‐type boutons. The quantitative analysis revealed that synaptic clefts are narrower and synaptic vesicles are smaller in symmetric F‐type boutons than in S‐type boutons forming asymmetric contacts. These data establish that at least three parameters (postsynaptic density, synaptic cleft, and size of vesicles) can be utilized singly or in combination to identify GABAergic inhibitory synapses in neocortex.
A new heavy‐metal‐containing resin for low‐temperature embedding and imaging of unstained sections of biological material
Authors: Acetarin Jean‐Dominique , Villiger Werner , Carlemalm Eric
Published: February 2005

A styrene‐based, low viscosity, negative‐staining resin has been formulated for low‐temperature embedding of unstained biological material. The resin, containing 3 atom% tin, permits sample preparations at 243°K, and provides sufficient contrast with bright field conventional transmission electron microscopy (CTEM) and excellent contrast in scanning transmission electron microscopy (STEM) ratio mode.
Influence of tissue composition on the final volume of rat liver blocks prepared for electron microscopy
Authors: Bertram John F. , Bolender Robert P. , Sampson Paul D.
Published: February 2005

Methods for measuring and evaluating changes in volume of small tissue blocks prepared for transmission electron microscopy are presented. The results indicate: (1) that some blocks swell and others shrink, and (2) that changes in block volume can be explained by inhomogeneous changes occurring in three different tissue compartments.

For stereological studies attempting to extrapolate changes in fixed and embedded tissue to those of fresh tissue, consequences of inhomogeneous volume changes in tissue compartments include a decrease in reliability and an increase in statistical variance of stereological density estimates. Since factors could not be found to correct for the changes in individual tissue compartments, alternative strategies are considered for dealing with the volume artifacts of fixation.
Ultrastructural patterns of ferritin permeation into glutaraldehyde‐fixed freeze‐fractured sarcomeres characterize stages of contraction in striated muscle
Authors: Barbosa Maria Luiza F. , Silva Pedro Pinto Da
Published: February 2005

We show that “fracture—permeation”—a method developed to assess the compactness of the cytoplasm—can establish the distribution of intermolecular spaces in the sarcomeres of glutaraldehyde‐fixed striated muscle. As examples of striated muscle, we use sartorius muscle from toad (Bufo marinus) and papillary cardiac muscle from the left ventricle of Sprague—Dawley rats. Tissues were fixed in glutaraldehyde, frozen, cross‐fractured in liquid nitrogen, and thawed. Tissue fragments were immersed in concentrated solutions of native ferritin (30% w/v). Random fractures gave ferritin direct access to all regions of the sarcomere. We show that a sequence of four qualitatively distinct patterns of ferritin distribution is associated to a progressive sequence of sarcomere lengths. The correspondence between sarcomere lengths and patterns of ferritin permeation permits the recognition of sarcomeres in rigor (no penetration of ferritin), stretched (penetration into the I band and H zone), or at rest length (penetration restricted to the I band). Similar patterns of ferritin permeation can also be recognized in oblique sections. In cardiac muscle, ferritin permeates into the A bands of contracted sarcomeres and shows an increase in disorder within the filament lattice during contraction. The patterns of ferritin permeation observed in sarcomeres in rigor, stretched, or at rest length are those predicted from changes in filament overlapping proposed by Huxley's “sliding filament theory of muscle contraction.” Our results illustrate the power of fracture‐permeation to investigate intermolecular distances in cytoplasmic matrices.
Specimen handling and data interpretation in x‐ray microanalysis of frozen hydrated etched gastrointestinal tract
Authors: Carr K. E. , Hayes T. L. , Watt A. , Bastacky S. J. , Klein S. , Fife M.
Published: February 2005

Low temperature scanning electron microscopy of mammalian tissue allows microanalysis data and morphological results to be considered together, without the risk of elemental diffusion introduced by liquid fixatives and processing agents. The technique, however, is time consuming and there are many areas where errors are possible and standardization of technique is advisable. The present paper describes some of the problems inherent in handling frozen tissue and comparison is made between microanalytical measurements from luminal contents and those from villous epithelium.
Preparation of lithium specimens for transmission electron microscopy
Authors: Liu Dang‐Rong , Rommal H. E. George , Williams David B.
Published: February 2005

A method of preparing undeformed thin lithium specimens for TEM is described. A solution of dehydrated methanol and toluene is used both for initial dishing of the foil by chemical polishing and also for final thinning. Under electron beam irradiation in the TEM, new pure Li crystals can grow out of the existing Li specimen. These in situ crystals can be used for the study of the microstructure and electronic structure of Li using TEM and electron energy loss spectrometry.