bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of dislocation geometries in the diamond cubic structure
Authors: Ray I. L. F. , Cockayne D. J. H. 
Published: August 2011

SUMMARYThe weak‐beam technique of electron microscopy (Cockayne, Ray & Whelan, 1969) has been applied to the examination of dislocations in germanium. These are shown to be dissociated into partial dislocations with a separation in the edge orientation of 5.5 ± 1·0 nm. A value for the stacking‐fault energy of γ = 60 ± 8 mJ m−2 (erg cm−2) is deduced from the measured dissociation width as a function of orientation, using anisotropic elasticity theory.
Transmission electron microscope observations of extended and unextended dislocation nodes in Si and Ge/Si layers using the weak‐beam technique
Authors: Cullis A. G. 
Published: August 2011

SUMMARYThe transmission electron microscope (TEM) weak‐beam method was employed in a study of dislocation nodes both in deformed single crystal Si and at the Ge/(lll)Si interface. All intrinsic nodes were observed to be extended, and measurements of their geometry in Si were used to determine the intrinsic stacking‐fault energy. However, only approximately half of the extrinsic nodes were extended and this was interpreted in terms of an energy barrier to node extension.
Four‐fold dissociations of super‐lattice dislocations
Authors: Crawford R. C. , Ray I. L. F. , Cockayne D. J. H. 
Published: August 2011

SUMMARYThe weak‐beam technique of electron microscopy (Cockayne, Ray & Whelan, 1969) has been used to image the four components of super‐lattice dislocations in a range of iron‐aluminium alloys, between 26 and 30 at % aluminium, with D03‐type long‐range order. Values of the first and second nearest neighbour interaction energies have been measured from the observed separations of the components.
Computer simulation of weak‐beam images of extended dislocations in copper
Authors: Perrin R. C. , Savino E. J. 
Published: August 2011

SUMMARYWeak‐beam electron microscope images of a dissociated edge dislocation in copper have been calculated using core configurations computed both from an atomic model and elasticity. These images show two distinct intensity peaks the separation of which is considerably greater in those derived from the atomic model. A comparison of these images with recently reported experimental observations suggests that the intrinsic stacking fault energy in copper is at least 70 mJ m−2 (erg cm−2).
Mechanisms of contrast and image formation of biological specimens in the transmission electron microscope
Authors: Burge R. E. 
Published: August 2011

SUMMARYA systematic account is given, in relation to amorphous and paracrystalline (especially biological) material, of electron scattering and image formation for the range of electron energy from 50 to 100 keV. Contrast mechanisms in both elastic and inelastic scattering are discussed and image formation is considered under both scattering contrast and phase contrast conditions.
Phase contrast electron microscopy of biological materials
Authors: Unwin P. N. T. 
Published: August 2011

SUMMARYThe properties of two electron microscope phase contrast imaging methods are compared. The first is the conventional bright‐field method in which dark phase contrast is created by defocusing; the second is a phase plate method in which bright phase contrast is created by means of a suitably shaped electric field.Using some negatively stained biological specimens which have a well‐known repeating structure as the test object, it is shown that the phase plate method has some important advantages over the bright‐field method. Its contrast transfer characteristics are such that it can provide a more faithful representation of the high resolution detail in the object. Moreover, by producing bright, rather than the normal dark, phase contrast it is able to simultaneously enhance the detail in the specimen and weaken the detail in the stain; this latter property enables the method to display information about the specimen that it would not be possible to detect with the bright‐field method.
Aspects of dark‐field electron microscopy
Authors: Perrier Frantz 
Published: August 2011

SUMMARYThis paper endeavours to give all the necessary practical information to operate with the contrast‐stop method as far as fairly thick objects (from 10 to 100 nm) are concerned; including working diagrams, practical operation out of the stops and also to define the range of application of this method. It is shown that false detail is not to be feared in these rather thick specimens, which is not at variance with the results obtained by Hanszen (1967, 1969) and Thon (1966) as far as very thin specimens are concerned.
Recent developments in analytical electron microscopy
Authors: Chandler John A. 
Published: August 2011

SUMMARYRecent years have seen the way in which the analytical electron microscope has been applied to problems involving thin specimens in metallurgy, mineralogy and many branches of biology. The limits of sensitivity have been explored and its potential usefulness in these fields investigated.Problems concerning the interaction of electrons with the specimen are discussed in relation to the correct choice of operating conditions and specimen preparation.In biological work, frozen sections provide new information about subcellular elemental localization of mobile electrolytes, while analysis of tissue prepared by conventional means is used to detect physiological levels of some naturally occurring elements.Examination of mineral dispersions provides analysis of particles just 10 nm thick, visible only in transmission electron microscopy, and further work with thin metal foils confirms the value of high resolution transmission imaging as a complementary facility to micro‐analysis.Work has been done to investigate the possibilities of improving sensitivities both by changing operational parameters and instrumental design, and the value of quantitation in thin specimen analysis explored.
Optimization of stereoscopic and high angle tilting procedures for biological thin sections
Authors: Willis Robin A. 
Published: August 2011

SUMMARYThe use of stereoscopic and high angle tilting facilities in electron microscopes to optimize information retrieval from thin sections of biological material is reviewed. Some of the technical problems involved are analysed in detail and problems of interpretation of stereo‐pairs and the necessity of ‘learning to see depth’ in such unfamiliar visual situations is emphasized. A table suggesting methods of optimizing various parameters is presented. An indication of some of the unanticipated results which have arisen from the work and of the consequent reservations about currently accepted routine evaluations of biological sections, especially as regards their thickness, are considered. The validity of serial section reconstruction at the 10–50 nm level needs careful consideration.
High voltage microscopy of biological specimens: Some practical considerations
Authors: Beeston B. E. P. 
Published: August 2011

SUMMARYTechniques are now available for the preparation of specimens giving excellent image contrast at high voltages, either by block‐staining, staining an already embedded block or by post‐staining. Further techniques are being developed for selectively staining certain features of the specimen thereby reducing the stain content of the specimen and permitting the examination of very thick specimens at adequate resolution.Specimens having inadequate contrast, particularly preparations of macro‐molecules, may be imaged in one of the various dark‐field modes, giving a considerable enhancement in image contrast on the viewing screen. Further enhancement of the recorded image contrast can be achieved by exposing the photographic plate to a much higher density than is normal.The complexity of image detail which occurs when the many features of a thick specimen are contracted into a two‐dimensional micrograph may be elucidated by stereo‐imaging techniques. Care must be taken to optimize the stereo‐tilt angles, the orientation of the tilt axis and the register of the two micrographs in the stereo‐pair, for the maximum depth in the specimen to be observed.
Quantitative photogrammetric analysis and qualitative stereoscopic analysis of SEM images
Authors: Boyde A. 
Published: August 2011

SUMMARYThis paper is concerned with methods for obtaining three‐dimensional (3D) information from scanning electron microscope (SEM) images. It may come as a surprise that this topic merits separate discussion, because, it is generally accepted that every SEM image of a rough surface using the secondary electron emission mode gives apparent 3D information. This is true to some extent, since SEM images are comparable with photographs of rough surfaces illuminated with light coming from one direction, but our main concern here will be with 3D visualization from stereoscopic pairs of images. However, there are other ways in which 3D information may be obtained, even in the SEM, and these are considered first. The remainder of the paper is largely concerned with the use of stereoscopic parallaxes, whether or not they are visualized as such. Commonly used methods for viewing stereo‐pairs are described, followed by simple methods for measuring stereoscopic parallaxes. Formulae for reducing linear measurements in the two photographs to real height differences are given.
Field‐ion microscopy of interphase interfaces
Authors: Hildon A. , Howell P. R. , Youle A. , Taunt R. J. , Page T. F. , Ralph B. 
Published: August 2011

SUMMARYThis paper demonstrates the use of the analytical techniques, developed in the companion paper, to determine interfacial parameters from a variety of multiphase structures. It is shown that accurate orientation relationships and the structure of unknown phases can be derived from this approach. In some cases assumptions have to be made concerning some of the interfacial parameters, but these assumptions can always be checked from the self‐consistency of the full analysis.
A method of microscopic evaluation of effects of demineralizers on complex carbohydrates of rat tissues
Authors: Weatherford Thomas W. , Mann Wallace V. 
Published: August 2011

SUMMARYMandibles, salivary glands, trachea, costal cartilages and kidneys of young adult, male, sibling rats were fixed in chilled, modified Lavdowsky's solution. The mandibles and blocks from the other tissues were then exposed to one of four demineralizers: Win 3000 and 20% formic acid, Greep's solution, 5% nitric acid and 10% EDTA. For comparison with demineralized tissues, a replicate set of tissues, other than mandibles, from each animal was processed without exposure to demineralizers.Paraffin sections of all tissues were stained with Alcian blue at pH 2–6 and at pH 0.5, with PAS and with Mowry's revised colloidal iron. The effect of the demineralizers on the staining intensities, tinctorial qualities, and cellular details were studied by pairwise comparison of each slide of a common tissue‐stain group with every other slide of the group. A comparison microscope was used and a numerically expressed preference ranking was obtained for each slide.Analysis of variance tests and Duncan's new multiple range tests were applied to determine the preferred demineralizers. Scoring results of the mandibles indicated that Win 3000 and 20% formic acid was either the preferred demineralizer or in each case not significantly different from the preferred one. Reliability of the findings was reduced because of inconsistencies among soft tissues not exposed to any demineralizer.
The application of optical microscopy and electron‐probe microanalysis to a mineral processing topic—the high‐temperature reduction of ilmenite
Authors: Jones D. G. , Stephens J. F. 
Published: August 2011

SUMMARYA combination of optical microscopy and electron‐probe microanalysis (EPMA) has been used to study the phases which occur during reduction of the mineral ilmenite to metallic iron and titanium oxides. Quantitative EPMA of natural and chemically‐processed minerals frequently suffers from variable specimen conductivity caused by the porosity and varying texture of the mineral grains. It has been found, however, that the element concentration ratios are largely independent of porosity and texture and can be used to identify the phases with precision.The microprobe has revealed some hitherto unsuspected effects arising from small concentrations of magnesium and manganese dissolved in the ilmenite lattice. The morphology and composition of the reduced product are in fact controlled by the way in which these impurity solutes segregate within the mineral grains during reduction.
Wetting agents for biological electron microscopy
Authors: Gregory D. W. , Pirie B. J. S. 
Published: August 2011

SUMMARYWhen preparing specimens for shadowing it is frequently necessary to add a wetting agent to aqueous suspensions to enable them to spread on hydrophobic support films. However high‐resolution platinum/carbon shadowing is capable of visualizing wetting agent molecules, so the effect of added wetting agent on the final appearance of the specimen must be considered. To facilitate interpretation of the specimen fine detail the background should be smooth and flat. This is achieved by using the concentration of wetting agent which produces a close‐packed monolayer of wetting agent molecules after drying. Bacitracin is a better wetting agent for use when shadowing than the commonly‐used bovine serum albumin (BSA). Because its molecules are smaller than those of BSA, the size of the background granularity is smaller, which facilitates interpretation of the specimen, and the layer of wetting agent molecules is thinner, so small specimen details are less likely to be buried and rendered invisible to the shadowing process. These points are described in detail and illustrated with the help of models where necessary.
Profiles of jet polished electron microscope specimens
Authors: Ali H. O. , Adams R. , Wann P. R. S. 
Published: August 2011

SUMMARYThe cross‐sectional profiles of jet polished electron microscope disc specimens have been measured as a function of (1) jet diameter, (2) electrolyte velocity, (3) jet to specimen distance, (4) lip thickness of clamping disc and (5) material used for the clamping disc. It is found that the optimum values of these parameters varies according to the material/electrolyte combination. However, a fault‐finding table has been devised which enables the optimum conditions to be found rapidly for any material.
Stereological correction procedures for estimating true volume proportions from biased samples
Authors: Mayhew T. M. , Cruz L.‐M. 
Published: August 2011

SUMMARYExperimental evaluation of component volume proportions may require the introduction of a component‐biased sampling approach in order to facilitate the unequivocal identification of cell type. Such is certainly the case for macrophages, neurons and cells of the lymphocyte‐plasma cell family. With these systems, mathematical corrections are necessary so that reliable morphometric information can be computed from the biased data. The type of correction procedure adopted will depend, to some extent, on the spatial relationships between the component of interest (nucleus, nucleolus) and its containing volume (cell, nucleus). In this communication, correction formulae for the special cases of spatial concentricity and eccentricity are derived. Their usefulness is illustrated by application to a number of well‐known model systems, and a reference table for obtaining the appropriate true volume proportion from observed (biased) data is provided. The reliability of the component‐biased morphometric approach is thereby increased.
Metal oxide systems studied by analytical electron microscopy
Authors: Fursey Anita , Kent B. , Saunders S. R. J. 
Published: August 2011

SUMMARYDetailed analysis of thin oxide films is providing a better understanding of the mechanisms of oxidation and corrosion. The analytical electron microscope used to study thin layers on iron‐chromium alloys has shown that even after oxidation times as short as 10 min at 600°C the ratio of iron to chromium in the surface oxide will be different from that in the underlying alloy and discrete nodules may well have a higher iron content than the protective film in which they are growing. Progressive changes in different morphological features of the oxide films grown at varying times and temperatures can be followed by micro‐probe analysis in EMMA 4. Results obtained from the oxidation in air of iron with 10% and iron with 20% added chromium are presented.
The use of the analytical electron microscope EMMA‐4 to study the solute distribution in thin foils: some applications to metals and minerals
Authors: Lorimer G. W. , Razik N. A. , Cliff G. 
Published: August 2011

SUMMARYResults are reported concerning the application of the analytical electron microscope EMMA‐4 to the quantitative analysis of thin foils. A simple procedure by which the observed characteristic X‐ray intensities from a thin foil sample can be converted into chemical weight fractions is described. This technique has been applied to study the partitioning of manganese between the carbide and ferrite phases during the isothermal decomposition of a eutectoid steel. The results show that it is possible to analyse the manganese content of the ferrite and carbide phases independently and the partitioning of manganese to the carbide phase has been followed as a function of time at the isothermal transformation temperature.The analysis of a calcium‐rich pyroxene which contains calcium‐poor precipitate lamellae is described. The results are consistent with the precipitation of a pigeonite, poor in calcium and rich in iron, from an augite host.The third example is the ‘in situ’ analysis of nitride precipitates in a stainless steel. The precipitates are known to contain either titanium or chromium, but it is impossible from morphological or diffraction evidence to differentiate between the two types of nitride. Combined electron microscopy and microprobe analysis is shown to be a rapid and positive means of identifying the precipitates.
Localization of acid and alkaline phosphatase
Authors: Bauer Heinz , Sigarlakie Elsje 
Published: August 2011

SUMMARYUltrathin frozen sections of glutaraldehyde fixed yeast cells have been successfully used for the demonstration of acid and alkaline phosphatase.Acid phosphatase was localized over the cell wall of both the mother cell and the bud as well as over the newly forming cross wall (septum). Cytoplasmic vesicles (vacuoles, lysosomes?) located close to the cell wall showed a positive reaction for acid phosphatase as well. After 3 h glutaraldehyde fixation an activation of the nuclear acid phosphatase was observed. Lead precipitates were predominantly found over the nucleolar material of ‘resting’ and budding cells.Alkaline phosphatase could be demonstrated in the ‘yeast‐mesosome’ and within the plasmalemma invaginations. After separation of the bud, small vesicles, probably derived from the endoplasmic reticulum showed a strong positive reaction for alkaline phosphatase.In frozen sections incubated for alkaline phosphatase, non‐specific lead precipitates were found in the nucleus and along the plasmalemma invaginations.
Growth of ice crystals in frozen specimens
Authors: Nei Tokio 
Published: August 2011

SUMMARYThe formation of ice crystals, which might be the possible artefact in cryo‐techniques for electron microscopy, was examined during the rewarming process of rapidly frozen erythrocytes.Intracellular ice formation, which is usually found in cells suspended in saline by rapid freezing, was inhibited by the addition of 30% glycerol. When such glycerinated cells, having no ice crystals at liquid nitrogen temperature, were rewarmed to higher temperatures above − 80° C, recrystallization of ice occurred. Ice particles became visible within the cells even at − 80°C and grew larger with a temperature rise.From the results obtained in the morphological and physiological investigations, it also became evident that the recrystallization of ice appeared prior to the increase in haemolysis during the rewarming process.
Performance characteristics of a microreflectometer for measuring autoradiographic grain density
Authors: Entingh Dan 
Published: August 2011

SUMMARYAn incident light microphotometer for measuring reflectance has been constructed from Wild M20 microscope components and Photovolt 520‐M photometer. The instrument measures autoradiographic silver grain densities in either small regions (5–30 μm diameter) or large regions (25–150 μm diameter) with an accuracy of greater than 90% compared to visual grain counts. Grain density measurements can be made in the presence of histological stains. The device speeds the collection of autoradiographic data by a factor of 10 or more, and can be used for 6 or 7 h per day without producing significant strain on the operator.
Some observations on knife properties and sectioning mechanics during ultramicrotomy of plastic embedding media
Authors: Helander Herbert F. 
Published: August 2011

SUMMARYThe edge and the trough surface of ultramicrotome glass knives were studied by interference light microscopy and electron microscopy. Particular attention was paid to the region which is commonly used for microtomy; here the bevel angle was calculated to 50–55°. The edge was serrated, even in the region used for sectioning, where the indentations measured up to 20 nm in depth. The imprints of edge serrations left on the sectioned material (Vestopal) were studied by electron microscopy. Different embedding materials displayed different degrees of compression when sectioned in the ultramicrotome: with Epon the compression was less than 10%, whereas methacrylate was compressed by more than 30%. Different trough fluids were tested: aqueous solutions of ethanol, acetone and dioxane gave less compression than pure water. However, the compression could also be reduced by exposing compressed Vestopal sections to these solutions. The direction and magnitude of the cutting force was measured with transducers during the sectioning of Vestopal blocks. Thus ∼0·3 μm wide sections cut at a feeding rate of 80 nm and a speed of 2 mm/sec required a cutting force of about 8 mN. The direction of the forces was 8–15° from the plane of cutting.
Histoquantitation using computer data cards
Authors: Meinhard Elizabeth 
Published: August 2011

SUMMARYThis paper describes a new approach to histoquantitation which makes fuller use of the visual expertise of the microscopist, provides a permanent visual two‐dimensional coded record, and allows mathematical exploitation of the collected data.The microscopic image of the specimen is traced directly onto computer data cards. A simple sketch records accurate quantitative data for areas and boundaries of as many components of the image as required, in a matrix of 840 points. Spatial relationships are maintained. The matrix is transferred by an Optical Mark Data Card Reader into a computer for extraction of a maximum of information.
A method for the fabrication of thin‐foil apertures for electron microscopy
Authors: Schabtach Eric 
Published: August 2011

SUMMARYA method is described for making thin foil apertures by piercing a plastic film with a heated microneedle and subsequently metallizing the plastic film by vacuum evaporation. Apertures can be made with diameters from 5 μm to 100 μm. They are round and very sharp‐edged and can be made in various patterns and combinations of sizes.
An anti‐roll plate for flattening of ‘dry’ ultrathin frozen sections
Authors: Hellström Sten , Sjöström Michael 
Published: August 2011

SUMMARYA simple anti‐roll plate has been designed for use in preparing ‘dry’ ultrathin frozen sections. The plate, which is made of a strip of a glass cover slip and attached close to the edge of a glass knife, prevents curling of the sections.