bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two rapid and simple methods used for the removal of resins from 1.0 μm thick epoxy sections
Authors: Maxwell M. H. 
Published: August 2011

SUMMARYUltrathin epoxy sections are commonly used in electron microscopy. More useful information can often be obtained by examining thicker (0.5–3.0 μm) resin sections under the light microscope. However, there are some histological stains that are unable to penetrate these resins.This short note describes the easy and rapid preparation of two resin‐removal solutions which allow subsequent staining of 1.0 μm thick sections without obvious tissue damage and with excellent results using standard histological dyes.
Identification of Gomori‐positive glia in autoradiographs
Authors: Goldgefter L. 
Published: August 2011

SUMMARYUnstained Gomori or paraldehyde fuchsin or chrome‐haematoxylin‐alum positive granules in the perikaria of so‐called Gomori‐positive glia of the periventricular zone of the rat hypothalamus, fixed with Bouin's or Carnoy's fluids, have been found to produce a positive chemographic (blackening) effect on autoradiographic emulsion. Similar action was produced by some granules in ependymal cells localized in the ventral part of the third ventricle between optical chiasma and median eminence. It is suggested that this positive chemographic effect can be employed for the identification and characterization of Gomori‐positive glia in autoradiographic studies.
Sephadex globules placed as landmarks in combined stereo microscopy, scanning and transmission electron microscopy
Authors: Thorball Niels 
Published: August 2011

SUMMARYRegions of specific interest in tissue blocks were localized in a stereo microscope and landmarked with Sephadex spheres (10–40 μm in diameter). This procedure made it possible to recognize these regions easily and quickly in the scanning electron microscope. When the tissue was later embedded in Epon the spheres facilitated orientation when sectioning. Thus it was possible with great certainty to determine the level at which ultrathin sections should be cut for transmission electron microscopy to attain an exact correspondence between scanning and transmission electron microscopic observations. The procedure is described and an example of its application is shown in a study of experimental hypertensive endothelial changes.
Scanning Electron Microscopy Of Uncoated Human Metaphase Chromosomes
Authors: Sweney L. R. , Lam L. F.‐H. , Shapiro B. L. 
Published: August 2011

SUMMARYHuman metaphase chromosomes were processed with a 3% glutaraldehyde‐tannic acid technique and examined in a scanning electron microscope at 20 kV either without added metal coating or with 2 nm of sputtered gold coating. Several substrates—aluminium foil, silver mirror deposit and sputtered gold—provided good conductive backgrounds for chromosomal spreads. Silver mirror deposit was the best conductive substrate tested. This method should prove to be a useful tool for monitoring the three‐dimensional morphology of mitotic chromosomes with the possibility of studying various banding techniques, chromosomal uncoiling and secondary constrictions currently being examined in chromosomal studies.
Differential Staining Of Cobalt‐ And Nickel‐Filled Neurones Using Rubeanic Acid
Authors: Quicke D. L. J. , Brace R. C. 
Published: August 2011

SUMMARYA staining procedure is described which differentiates with distinct colours, cobalt and nickel ions introduced into neurones. Densely coloured precipitates are produced with these ions when rubeanic acid, a spot‐test reagent, is added. Formation of the coloured complexes takes place within a few minutes, and may be followed under the dissecting microscope. This technique permits observation of the relative positions, within ganglia, of somata related to two emergent nerves following multiple axonal‐backfilling. It also appears to be of value in tracing neurone branching after the intracellular injection of ions.
Electron Microscope Autoradiography Of A Diffusible Intracellular Constituent, Using Freeze‐Dried Frozen Sections Of Mammalian Intestinal Epithelium
Authors: Johnson I. T. , Bronk J. R. 
Published: August 2011

SUMMARYAutoradiograms were prepared from freeze‐dried frozen sections of rat intestinal epithelium, previously incubated in vitro with 3H‐galactose. Although the sections snowed evidence of disruption by ice‐crystal growth during freezing, they retained sufficient recognizable ultrastructure to facilitate the identification of several subcellular compartments. Statistical analysis of the grain distribution indicated that a significant non‐uniform distribution of the labelled galactose occurs in the absorptive cells during transport, and is maintained in the sections throughout the various stages of autoradiography.
Topography And Thickness Of Air‐Dried Human Platelets Measured By Correlative Transmission And Scanning Electron Microscopy
Authors: Hui S. W. , Costa J. L. 
Published: August 2011

SUMMARYHuman platelets rapidly air‐dried on carbon‐coated grids were examined by transmission and scanning electron microscopy. Whole cell mounts were photographed in a transmission electron microscope (TEM), coated with gold, and then examined in a scanning electron microscope (SEM). The thickness of the cytoplasm towards the centre of the cells was estimated to be 20–40 nm, and the rim of dense material surrounding the cells was 40 nm thick. Some dense bodies stood out as much as 100 nm above the dried cytoplasm. These measurements are important for evaluating cytoplasmic volume during microprobe analyses of air‐dried platelet preparations.
A Technique For Illuminating Early Chick Embryos In Ovo With A Glass Rod As A Light Guide
Authors: Dryden R. J. 
Published: August 2011

SUMMARYA glass rod mounted on a microscope condenser acts as a light guide through the yolk of a fertile hen's egg. Two apertures must first be made in the shell: the one below covered with plastic film which seals around the rod; the one above covered with a glass coverslip to allow microscopic observation of the embryo.
Resolution Of M23C6/Austenite Phase Boundary Defect Structures By Weak Beam Microscopy
Authors: Nilsson J.‐O. , Dunlop G. L. 
Published: August 2011

SUMMARYThe weak beam dark field imaging technique has been successfully applied to the problem of imaging misfit dislocations at the interface between M23C6 precipitates and an austenite matrix. The technique eliminates Moiré fringe contrast which otherwise obliterates the contrast from interfacial dislocations. Three sets of parallel dislocations were observed with spacings and line vectors consistent with them being edge dislocations with Burgers vectors of a/3<111>.
Progression Of Fusion During Rapid Freezing For Electron Microscopy
Authors: Van Harreveld A. , Trubatch Janett 
Published: August 2011

SUMMARYThe method used to determine the rate of fusion was based on the large difference in the dielectric constants of water and ice. A thin (50–60 μm) slice of a gelatin gel was used as the dielectric in a plate condenser. The slice was placed on a metal electrode built in a specimen carrier which was dropped on a silver freezing surface kept at below 70 K, forming the other plate of the condenser. Freezing of the gelatin causes a marked decrease in a 20,000 cycle current passing through the condenser. Since the thickness of the layer of frozen material was shown to be a function of the reciprocal of the current, it was possible to determine the course of fusion of the section. Freezing started at a high rate which declined during the first 5 ms but then increased again and usually became quite high at the end of fusion.
Intercellular Junctions In Fanft‐Induced Carcinomas Of Rat Urinary Bladder In Tissue Culture: In Situ Thin‐Section, Freeze‐Fracture, And Scanning Electron Microscopy Studies
Authors: Pauli Bendicht U. , Kuettner Klaus E. , Weinstein Ronald S. 
Published: August 2011

SUMMARYThis paper describes a set of simple methods for comparative light and electron microscopy studies on tissue cultured tumour cells derived from both noninvasive and invasive carcinogen‐induced rat urinary bladder carcinomas. Cells are grown on Thermanox plastic coverslips and fixed in situ. Each plastic coverslip is then divided with scissors into four parts: the first is processed for light microscopy, the second for thin‐section electron microscopy, the third for freeze‐fracture electron microscopy, and the fourth for scanning electron microscopy. In some experiments, portions of the culture which have first been examined by light microscopy are subsequently prepared for electron microscopy. In this way, the culture conditions are kept constant and a comparison of structural features (i.e. intercellular junctions) by several preparative techniques is possible.Noninvasive and invasive rat bladder tumour cells, characterized by numerous pleomorphic microvilli, have normal zonulae occludentes at the apices of lateral surfaces of tumour cells in all cultures. In some areas of invasive tumour cells, occludens junctions are focally attenuated, consisting of only one or two strands, and occasionally the strands are discontinuous. Gap junctions, type PF‐1, as well as numerous desmosomes are present in all cell lines. Thus, intercellular junctions in noninvasive and invasive rate bladder epithelial cell lines bear a striking resemblance to those previously described in the comparable solid primary tumours. These culture systems may be useful for studying factors which influence the formation of intercellular junctions during malignant transformation.
Electron Microscopical Techniques For The Observation Of Cavities
Authors: Stobbs W. M. 
Published: August 2011

SUMMARYThe full range of methods by means of which cavities can be examined using a transmission electron microscope are reviewed. Different techniques are required in different circumstances and the extent to which a quantitative interpretation can be given is discussed for a number of examples. These range from the use of structure factor contrast for relatively large pores through the use of Fresnel contrast for intermediate sized pores with a dimension in the 0·4–20 nm range to elastic side band imaging and atomic resolution techniques for pores with sizes less than about 0·6 nm.
An Introduction To The Development And Effects Of Voids In Sintered Materials
Authors: Exner H. E. 
Published: August 2011

SUMMARYSintered materials usually show residual porosity which influences their properties. The present views on the development of the structure during processing (pressing, sintering) and some correlations between void structure and properties are reviewed. The important rôle of microscopy in the qualitative and quantitative evaluation of void structures is emphasized.
Microscopy Of Voiding During Creep Of Alpha‐Brass
Authors: Elliott I. C. , Wilshire B. 
Published: August 2011

SUMMARYMetallographic and fractographic methods have been used to study void formation during high‐temperature creep of alpha‐brass. The appearances of the creep fracture surfaces were found to differ markedly at high and low stress levels. Cavity development was therefore monitored using samples tested to various fractions of their creep lives which were then fractured in an intergranular manner by stress‐corrosion at room temperature. The different modes of void formation observed can be rationalized in terms of a model for cavity growth based on the movement of lattice dislocations in the plane of the grain boundary.
Depth Distribution Of Swelling In Ion‐Bombarded Stainless Steels
Authors: Lauritzen T. , Konze G. M. , Bell W. L. , Appleby W. K. 
Published: August 2011

SUMMARYNickel ion bombardment has been extensively used to simulate and study swelling caused by neutron irradiation induced void formation in stainless steels. We have developed techniques to utilize the variations in displacement damage with depth from the ion‐bombarded surface to obtain swelling measurements for differing total displacement doses and dose rates from a single specimen. These techniques are not only cost effective, but have the advantage of conserving scarce material in those experiments involving specimens bombarded after prior reactor irradiation.Nickel ions accelerated to 5 MeV have a range of about 1400 nm in stainless steel with the peak displacement damage occurring at a depth from the surface of approximately 900 nm. Thus, TEM examination of the microstructure at successive depths to 900 nm allows measurement of void swelling at various displacement doses. We accomplish this by stepped removal of the material in the plane normal to the incident ion beam. The ion entry surface is successively partially masked with lacquer and then ion milled to various depths. The foils are then perforated at the various depths by backthinning electrochemically. Results are presented which show the dose dependence of swelling obtained in this way for AISI 316 stainless steel bombarded to 115 dpa with up to 35% swelling. The results are compared and contrasted with dose dependencies of swelling obtained from examination of specimens separately bombarded to different peak doses up to 115 dpa.
An Atomistic Study Of The Structure Of Grain Boundary Dislocations
Authors: Sutton A. P. , Smith D. A. , Vitek V. 
Published: August 2011

SUMMARYComputer atomistic calculations of the structure of edge grain boundary dislocations in coincidence boundaries have been carried out using a central force pairwise potential to describe the atomic interaction. The calculations show that close packed configurations of atoms exist in the cores of the dislocations. They also suggest that under certain specified conditions the structures of some grain boundary dislocations with Burgers vectors having the same magnitude but opposite signs on the same boundary facet can have different atomic structures. This is found to depend on the symmetry of the boundary plane, the driving force for dissociation into symmetry relating partials, the kinetics of the dissociation reaction, and the source of the dislocations.
The Structure Of Interphase Boundaries In Solids
Authors: Laird Campbell , Sankaran Ramanathan 
Published: August 2011

SUMMARYAlthough, in principle, the structure of solid interphase interfaces should be no different from those of regular grain boundaries in homophase materials, it is shown that special boundaries characterized by a high degree of order occur much more frequently in interphase boundaries than in homophase boundaries. This is mainly caused by the fact that complex phases are usually produced at the end of the processing history of a material. Thus precipitates, eutectics, the products of spinodal decomposition, martensites, surface precipitates, epitaxially‐deposited heterojunctions and similar materials all tend to have special boundaries. On the other hand, multiphase materials subject to the same kinds of thermo‐mechanical processing as homophase materials, e.g. duplex steels, alloys with grain boundary precipitates, and superplastically deformed materials, possess interphase boundaries closely akin to those of homophase materials. The origins and structural details of the different kinds of boundaries are explored.
Electron Microscopy Of Interfaces Between Transforming Polytypes In Silicon Carbide
Authors: Jepps N. W. , Page T. F. 
Published: August 2011

SUMMARYHigh resolution transmission electron microscopy, utilizing tilted illumination lattice imaging techniques, has been used to examine the structure of interfaces between transforming polytypes in cubic silicon carbide samples subsequent to annealing heat treatments. Though structure projection images have not been possible, detailed observation of the twinned cubic, 3C/6H and 3C/4H interfaces have been made including stacking sequence information observed with ∼ 0·25 nm lattice fringes. In contrast to the apparently strain‐free coherent conditions found at twinned cubic and 3C/6H interfaces, 3C/4H interfaces were observed to be coherent but with a short‐range strain field periodic over every twelve layers of the cubic structure. The 3C/6H transformation has been clearly observed to initiate at twin interfaces and to proceed by the propagation of steps of unit‐cell height along the coherent interface. The implications of these observations for phase transformations in silicon carbide, together with the necessary associated structural rearrangements, are discussed. Finally, some preliminary observations (utilizing impurity‐sensitive SEM contrast, together with the optical examination of thin foils in polarized light) concerning possible impurity redistributions and anomalous grain growth effects during polytypic phase transformations are presented.
Computer‐Controlled Double‐Beam Scanning Microspectrophotometry For Rapid Microscopic Image Reconstructions
Authors: Kuc̆era P. , de Ribaupierre Y. , de Ribaupierre F. 
Published: August 2011

SUMMARYA method for automated collection of various specific data from an entire microscopical preparation and their quantitative evaluation is described. Its application to the study of neuronal connections is discussed in some detail.Brain sections are scanned using a computer‐controlled microscope for reflectance, fluorescences or absorbance signals. Two illuminating beams are used, one of them being amplitude modulated. By means of a synchronous detection the two signals are recorded simultaneously: for example, in an autoradiograph, the reflectance (measuring the density of the silver grains in the emulsion) and the absorbance (allowing to localize the underlying counterstained cells). The data are stored in a computer.Various off‐line processing schemes allow the reconstruction of the data with respect to the corresponding spatial coordinates. Thus pseudo‐three‐dimensional, analogue or digital, graphic displays may be obtained in which the patterns of neuronal connections can be recognized and interpreted. A method for the detection of weakly labelled nerve fibres based on digital filtering is presented.The whole processing for a frontal section of the mouse brain (7 × 10 mm area) takes less than 1 h.In addition to the evaluation of microscopically labelled material (grains of auto‐radiographs, horseradish peroxidase, nucleic acids) the technique described has been successfully used for the study of naturally fluorescent intracellular components in living tissue cultures.
The Use Of The Texture Analyser To Study Sinter Structure: Application To The Morphology Of Calcium Ferrites Encountered In Basic Sinters Of Rich Iron Ores
Authors: Greco A. , Jeulin D. , Serra J. 
Published: August 2011

SUMMARYQuantitative image analysis applied to iron ore sinters gives complementary information to chemical analysis such as quantitative mineralogical analysis, and also quantitative geometric properties of crystals and of porous networks (size distribution, repartition). Spatial disposition of sinter components produced during crystallization builds different textures which are well known to mineralogists. The types of textures encountered can be related to initial composition, cooling conditions and to physical properties of the sinter (mechanical strength, reducibility). In order to estimate the relative importance of each texture in a sinter, measurements made using a pattern recognition procedure are required.Algorithms for automatic pattern recognition were established for calcium ferrites texture encountered in rich iron ore basic sinters. They depend on a specific treatment of morphological parameters estimated inside fields of measurement of the texture analyser. Furthermore, mathematical models of multicomponent structures based on mathematical morphology, are used for different calcium ferrites textures. The parameters of these models are estimated from experimental measurements made with a texture analyser.The present study is a part of a research programme made by IRSID (Institute of Research of French Steel Industry) on the structure of iron ore sinters in order to explain variations of their physical properties related to their behaviour in the blast furnace.
Guinea‐Pig Keratinocytes And Melanocytes In Tissue Culture: Scanning, Transmission And High Voltage Electron Microscope Observations
Authors: Merriman J. A. , Nieland M. L. , Wedmore R. J. 
Published: August 2011

SUMMARYKeratinocytes and melanocytes cultured from guinea‐pig epidermis were studied with scanning, transmission and high voltage electron microscopy to characterize the surface and internal morphology. Keratinocytes exhibited contact‐inhibition and a range of surface structures consistent with cell‐cycle dependent changes. Stereoscopic analysis of high voltage electron micrographs indicated regular oval nuclei with nucleoli at different depths, while thin sections revealed local channels in the nuclei. Secondary cultures differed from primary cultures in the disorder of the microfilaments, in the failure to form desmosomes, and in the failure of melanocytes to persist in culture. The beaded surface of melanocytes was indicative of underlying melanosomes that were seen in high voltage micrographs. Melanocytes were rounded with moderate ruffles or were dendritic with ruffles on the termini. These findings are discussed in relation to the observational techniques and in relation to modes of locomotion of and pigment transfer to epidermal cells.
A Device For The Reproducible Spreading Of Cryoultramicrotome Sections
Authors: Williamson Francis A. 
Published: August 2011

SUMMARYA device has been designed and constructed to electrically heat frozen sucrose solution droplets within the cryochamber of a cryomicrotome. This ensures that the solution liquefies to spread the sections before they melt and collapse, and allows many more sections to be cut continuously.
The Evaluation Of Cell Nuclei Staining Parameters Regarding The Reproducibility Of Fluorescence Measurements
Authors: Matzke K. H. , Thiessen G. , Tiffe H. W. 
Published: August 2011

SUMMARYThe present methodological study is an attempt to optimize the staining parameters for a quantitative DNA determination of fluorescent cells. The application of pure dyes and a precise control of the staining procedure are preliminary conditions which have to be fulfilled, because the reproducibility of measurements is in this connection the most important criterion for a quantitative DNA related analysis of cell population.Chicken erythrocytes and isolated nuclei were applied as biological test objects. The staining procedure with acridine derivatives (acriflavine, proflavine, rivanol) was performed in accordance with the fluorescence‐Feulgen reaction. The influence of staining parameters, such as (1) pH and (2) dye concentration of the staining solution, were evaluated regarding the spectral behaviour, the total fluorescence intensity, and the reproducibility of results.
Recent Advances Of High Voltage Electron Microscopy In Biology
Authors: Glauert Audrey M. 
Published: August 2011

SUMMARYRecent advances in the understanding of the structure of biological material made possible by the high voltage electron microscope are reviewed by briefly summarizing some of the more important results obtained in the past few years. The examination of thick sections of selectively stained specimens has continued to be the most widely used approach and has yielded information on the three‐dimensional organization of a range of organelles, including the Golgi apparatus, neurofibrils and the transverse tubular system of striated muscle. The alternative method of studying intact cells prepared by critical‐point drying is becoming increasingly popular, and has already made a significant contribution in demonstrating the microtrabecular systems within the cytoplasm of cultured cells.