bluuebunny/crossref_metadata_2025_split huggingface dataset:
Erythrocyte membrane topo‐optical staining reflects glycoprotein conformational changes
Authors: Geyer Günther , Makovitzky Josef 
Published: August 2011

SUMMARYThe study is concerned with the relationship of induced birefringence to conformational alterations of glycocalyx glycoproteins. Human erythrocytes washed with phosphate‐buffered saline (PBS) and fixed with glutaraldehyde exhibit the most intense topo‐optical staining, which is thought to reflect the lipid bound state of glycophorins. Incubations at reduced pH, in hypotonic media or in the presence of procaine resulted in a significant decline of induced anisotropy. The effects were not due to degradation of glycocalyx constituents. Erythrocytes subjected to treatments with procaine or at pH 6Ṁ2 suffered from loss of electrophoretic velocity, a finding indicative of rearrangement of cell surface glycoproteins. By example of the red blood cell the findings of this study confirm the premised suggestion of the sensible detection by topo‐optical toluidine blue staining of the conformational state of glycoproteins of the glycocalyx.
A simple technique for the examination of urothelial surface morphology by transmission electron microscopy: platinum‐carbon replicas of critical point dried bladder tissue
Authors: Severs N. J. 
Published: August 2011

SUMMARYA simple technique is described for the examination of bladder luminal surface morphology by transmission electron microscopy (TEM). Pieces of bladder tissue are critical point dried and replicated with platinum‐carbon in the manner standard for freeze‐fracture. The large intact areas of replica produced show improved resolution of detail compared with scanning electron microscopy (SEM), and allow the survey of larger expanses of membrane than is possible with standard TEM techniques. Comparison of the structure observed in platinum‐carbon replicas of critical point dried tissue with that seen in frozen‐surface replicas, freeze‐fracture replicas and thin‐sections reveals the presence of artefacts in the critical point dried specimens which are not detected by SEM. Similar artefacts are evident in replicas of partially freeze‐dried samples. The nature and origin of these artefacts are discussed. It is concluded that replicas of critical point dried specimens provide useful information on surface morphology at magnifications intermediate between those normally used with standard TEM and SEM techniques. The details of surface morphology viewed by this method are discussed with particular reference to the structure of the intercellular boundary.
A fibre optic ring illumination system for use in low‐powered dark field (including Rheinberg method) video, cine and photomicrography
Authors: Lawrence Michael J. 
Published: August 2011

SUMMARYA fibre optic ring illuminator normally used as a reflected light source with a low‐powered microscope is here used as a substage illuminator with a stereo zoom microscope, to give uniform dark field (dark ground) illumination. This development was primarily for use in colour video recordings giving good contrast pictures but can also be used successfully in cine and photomicrography, at magnifications ranging from x 1ṁ5 to x 124. Its application is particularly suitable for the observation of biological specimens.
Action of gibberellic acid in a dwarf maize mutant: an X‐ray microanalysis study
Authors: Neumann D. , Jánossy A. G. S. 
Published: August 2011

SUMMARYA method is described to prepare plant tissue for X‐ray microanalysis. Model experiments with radioactively labelled ions show that freeze substitution can be used for the retention of soluble ions under controlled conditions. For calculations of absolute values a combination of the ratio method and the continuum method is used with dentine as the only standard.An X‐ray microanalysis study of the action of plant hormones was performed with a dwarf maize mutant, sensitive to minimal amounts of the plant hormone gibberellic acid (GA3). The dwarf corn mutant shows completely different concentrations of K+, Ca++ and Cl in chloroplasts, cytoplasm and vacuoles in comparison with the normal plant. GA3 produces changes of the ion concentrations similar to those of the normal plant. Short‐term experiments (1‐4h action of the hormone) also result in changes in the ion concentrations, specifically due to the hormone. The structurally similar by physiologically inactive GA3 methylester causes a response comparable to that of water.
Ultrastructural effects of the high molecular weight cryoprotectants Dextran and polyvinyl pyrrolidone on liver and brown adipose tissue in vitro
Authors: Barnard Tudor 
Published: August 2011

SUMMARYThe ultrastructural changes caused by incubation of rat liver and brown fat in buffered solutions of high molecular weight cryoprotectives (Dextran and polyvinyl pyrrolidone) at high concentrations (up to 25% w/v) have been examined. Under appropriate conditions of incubation rather small qualitative changes were found. Hepatocytes showed some signs of plasmolysis. Evidence for the endocytosis of Dextran and polyvinyl pyrrolidone was obtained. Cryoultramicrotomy of unfixed, quench‐frozen specimens after the same incubation procedures showed good cutting properties and only slight ice‐crystal damage. Several of the larger tissue compartments were recognizable in such sections. Although high molecular weight cryoprotectants do penetrate cells by endocytosis (and these effects require further functional evaluation), the present observations provide further support for the idea that such compounds significantly improve the quench‐freezing of biological specimens and offer a practical way forward for the preparation of material for X‐ray microanalysis of diffusible elements.
Optical diffraction: applications to lamellar microstructures
Authors: Andrews K. W. , Keown S. R. 
Published: August 2011

SUMMARYOptical diffraction techniques have a wide range of applications which extend from the further interpretation of electron micrograph images to aerial photographs. Useful metallographic applications are based on optical or electron micrographs.A brief account is given of a typical system for obtaining optical transforms or diffraction patterns and reconstituted images. Structures which appear frequently in eutectics or eutecoids show laminations arising from the alternating formation of different constituents with planar interfaces. The diffraction patterns are relatively simple but may be affected by variations in spacing and orientation. Account should also be taken of geometrical and other factors due to the tilt of the lamellae with respect to the surface. Besides recording the spacings it is also useful to take account of the directions of traces in the surface in view of the possible presence of structural anisotropy.The eutectic which is the sole constituent in alloys containing aluminium with 33% copper provides a useful illustration of the principles. Some typical results are briefly presented.A second application refers to ‘pearlite’, the eutectoid which forms in iron‐carbon alloys and many carbon and low alloy steels. The alternating lamellae are α‐iron and the carbide Fe3C. Two examples are given. The first refers to the use of spacing measurements in order to examine the dependence on temperature of transformation. The second shows how statistical spacing variations in a micrograph may reveal whether there is one or more basic spacing. The variation of the trace directions reveals structural anisotropy, and the relation of the spacing to this anisotropy is also examined.
One micrometre paraffin sections: an aid to interpretation of immunoperoxidase staining of immunoglobulins
Authors: Judd Mary A. 
Published: August 2011

SUMMARYA technique is described for obtaining 1 μm sections of tissue embedded in modified paraffin wax using long‐edged glass knives. Serial sections can be cut and stained by the immunoperoxidase method to demonstrate multiple antigens in a single cell or to confirm that the immunoglobulin within a cell is monotypic. The improved cytological detail seen in thin paraffin sections permits the more precise localization of intracellular staining.
The classification of microstructures of clay soils
Authors: Sergeyev Y. M. , Grabowska‐Olszewska B. , Osipov V. I. , Sokolov V. N. , Kolomenski Y. N. 
Published: August 2011

SUMMARYThis paper presents the results of experimental studies on the microstructure of clay soils, using scanning electron microscopy. Approximately 300 samples of clay soils of various ages, origin and degree of lithification have been analysed. Five main types of microstructure have been identified in clay soils of sedimentary origin, i.e. honeycomb, skeletal, matrix, turbulent and laminar. Among clay soils of sedimentary origin and hydrothermal origin three types of microstructure were distinguished; domain, pseudoglobular and globular.In natural environments, microstructures of mixed features have been found, i.e. honeycomb‐matrix, honeycomb‐skeletal, turbulent‐matrix, etc.The detailed description presented of the different microstructural types comprising morphology and quantitative calculations, shows a close relationship with mineral composition, origin and degree of lithification.In addition physical and mechanical properties as well as the resistance and deformation indices of clay soils have been found to be related to microstructural features.
Use of the scanning electron microscope and Fourier methods in characterization of microfabric and texture of sediments
Authors: Gillott J. E. 
Published: August 2011

SUMMARYBehaviour of soils and sediments is generally assessed by laboratory tests of mass property relationships and semi‐empirical equations. A basic approach calls for more detailed information concerning the properties of sediments and manageable methods of calculation. The scanning electron microscope is now providing data concerning the fabic, diagenesis and weathering of sediments. Some sediments are fragile and care is needed in sample preparation to avoid the introduction of artefacts. For example, moisture removal is often accompanied by dimensional change. Freeze drying and critical point drying appear to reduce this problem.Quantitative methods of fabric and texture analysis are being developed, the data being processed by computer. The Fourier method is able to provide quantitative information concerning shape and texture of particles. This sort of information has been used in studies of provenance, correlation, pedogenesis and environmental processes.Examples are given of the use in engineering of fabric and textural data obtained by the Fourier method and by microscopy.
Experimental etching of a microcline perthite and implications regarding natural weathering
Authors: Wilson M. J. , McHardy W. J. 
Published: August 2011

SUMMARYMatching 010 and 001 cleavage faces of a microcline perthite from Arendal, Norway, were hydrothermally etched for increasing periods of time. On both faces the interface between the two felspar phases quickly becomes etched, enhancing the contrast between them and indicating dislocations in the plane of the perthitic lamellae. Moreover, on the 010 face, etch lines reveal dislocations which transect the lamellae parallel to the trace of 001 cleavage. In all probability these dislocations result from the strain arising from partial coherence of the two felspars. The microcline matrix develops innumerable rhomboidal‐shaped etch pits on the 001 face and pits with an elongated parallelogram‐shaped outline on the 010 face. The dominant direction of etching is parallel to the pericline twinning, suggesting that dislocations occur within the pericline twin boundaries. At a later stage micro‐crystalline boehmite develops preferentially in the perthitic lamellae and along the dislocations parallel to the (001) plane. Such sites may be particularly favoured for clay mineral formation during natural weathering.
Towards the quantification of soil structure
Authors: Bullock P. , Murphy C. P. 
Published: August 2011

SUMMARYUsing the technique of image analysis it is now possible to make advances in the quantification of soil structure which were not previously possible because of laborious methods and techniques. For the purposes of quantification aggregated soil material is distinguished from non‐aggregated soil material. Aggregated material is characterized by the aggregates themselves and inter‐ and intra‐aggregate pores. Basic measurements on aggregates and pores include size, area, perimeter, Feret's diameter and projection, and these are supplemented by derived measurements such as shape, irregularity and orientation. Non‐aggregated soil material is characterized by pore patterns, defined by the types of pores, and their size, statistical distribution, irregularity and orientation. Quantification of structure is important in a number of fields of soil science and these are briefly summarized.
The microfabric of deformed kaolin
Authors: Tovey N. K. , Wong K. Y. 
Published: August 2011

SUMMARYSamples of remoulded kaolin have been subjected to varying consolidation and shearing stress conditions, and the resulting microfabric has been examined using a scanning electron microscopy and an X‐ray texture diffractometer. Preparation of samples for observation in the SEM involved both freeze‐drying and critical point drying methods. In consolidation experiments, a significant regional variation in the degree of orientation is observed in each sample. An increase in orientation is seen near drainage surfaces. Observations from areas remote from these surfaces on samples consolidated one‐dimensionally show that from 0 kPa to 100 kPa there is little increase in the general degree of orientation. However, the large decrease in voids ratio associated with this change of stress level is achieved by aggregation of particles into domains, the latter being randomly orientated with respect to one another. Above 100 kPa, the degree of orientation increases, as the particles show a tendency to align with their normal vectors parallel to the principal stress direction.These findings are in agreement with the X‐ray texture goniometer studies on impregnated specimens cut from parts of the consolidated samples adjacent to those for scanning electron microscopy studies. The surfaces of specimens for the X‐ray studies were cut orthogonal either to the major principal stress direction or to the space diagonal in σ1, σ2, σ3 space.Micrographs of kaolin consolidated one‐dimensionally in one direction and then to a higher stress level in an orthogonal direction show a closely packed near random fabrics. Examination of samples deformed in shear reveal narrow zones, although regular herring‐bone‐shaped kink bands have been seen in the region between two parallel shear zones.
SEM morphologies of halite (NaCl) in soils
Authors: Eswaran H. , Stoops G. , Abtahi A. 
Published: August 2011

SUMMARYHalite (NaCl), the most common halide mineral, is omnipresent in saline soils and frequent in alkaline soils. The present study, with a scanning electron microscope, is undertaken to evaluate the morphologies of this mineral in soils and a recent sediment.Salorthids, from Iran and Syria, and a recent crust from the beach of a lake, are employed. The major part of the crust on the surface of the soil is composed of diffuse, waxy and massive forms of halite. The morphology is attributed to the hydroscopic nature of the salt which dissolves in its own absorbed water and crystallizes to give these forms. Directly on the crust surface is a layer of thin fibrous halite which shows elongation along the [100] axis. In the porous parts of the crust, secondary growths occur on the waxy and massive forms. The crystallites have a partially developed hexahedral habit and, according to their orientation, appear as cubes or as trigonal pyramids. In some cases the cubes grow along the axis normal to the surface, resulting in prismatic or acicular habits.In salic horizons the massive form is dominant. Euhedral forms only occur on the exposed face of the soil pit or on the pit floor. Perfect cubes—hexahedral—develop here.
Morphology, composition and genesis of argillans and organans in soils
Authors: Ranst E. Van , Righi D. , Coninck Fr. De , Robin A. M. , Jamagne M. 
Published: August 2011

SUMMARYThe accumulation of clay and organic material, forming argillans and organans, is poorly understood and is at least not a subject of general agreement. Electron scanning and microprobe show striking features. The argillans, having Si, Al and Fe, are clearly layered and seldom cracked. The organans do not contain Si, but either Al only, or Al and Fe, are not layered, but are composed of discrete very small bodies, stacked at random. They have a strong polygonal cracking pattern, indicating a shrinking process.The morphology of argillans seems inconsistent with a flocculation process, which would give a porous structure with much water, so that the strong layering is obviously due to a slow deposition of layer silicates out of a dispersed phase.The organans are formed by deposition of gel‐like organo‐metallic compounds and evaporation of the solvation water, causing a strong shrinking.
The electron microscopic studies of pore space of solids by a method of conjugate surfaces
Authors: Sokolov V. N. , Osipov V. I. , Tolkachev M. D. 
Published: August 2011

SUMMARYThis paper presents a new method of studying pore space of solids with the help of SEM images. The method in question consists of obtaining true images of the specimen microstructure and its further processing by the Image Analyser. The above‐mentioned image appears as the result of superimposing exactly corresponding SEM images which can be observed on both (conjugate) surfaces of the fractured specimen. Therewith, the dark spots on the total image unambiguously represent pores, whilst bright spots represent grains and particles. The following estimates of the pore space are made by automatic Image Analyser of the total image: the determination of total, open and effective porosity; permeability; distribution pores according to its size; the channel tortuosity.
Quantitative studies and theoretical analysis of the performance of the scintillation electron‐detector
Authors: Comins N. R. , Thirlwall J. T. 
Published: August 2011

SUMMARYThe performance of the scintillation electron‐detector is evaluated in terms of the output signal‐to‐noise ratio and detective quantum efficiency (DQE). An expression is presented which relates the statistical behaviour of each section of the detector in the STEM configuration to the DQE of the whole system and which also relates this DQE to the detector output signal. This expression is employed to correlate quantitatively the data measured using three types of scintillator under various operating conditions and also during scintillator deterioration caused by electron irradiation. It is shown that the influence of changes in design parameters on the DQE can then be predicted.
The measurement of cell volume and surface area by SEM photogrammetry
Authors: Kristensen Steen E. L. , Papadimitriou John M. 
Published: August 2011

SUMMARYThe problem of measuring singly the volumes and surface areas of macrophages with their complex and variable morphology was dealt with by the photogrammetric analysis of stereoscopic SEM micrographs. The reproducibility of these measurements was found to be greater than 95%, using the most basic stereophotogrammetric techniques.
Modified development to improve the performance of AR10 stripping emulsions for use with the more energetic isotopes
Authors: Sanderson J. 
Published: August 2011

SUMMARYGold latensification of the image to increase the efficiency of the more energetic isotopes, such as 14carbon, has been used before for liquid emulsions, with mild developers, but never successfully with AR10 stripping emulsion.This paper describes the performance of different developers and assesses their ability to suppress background fog on Kodak AR10 emulsion. A 14carbon source was used and the effect of gold latensification was examined.Kodak D19, an efficient Metol/hydroquinone developer, could be usefully modified by altering the sodium carbonate and sulphite contents (D19 A/S). This developer discriminated well against the background with AR10 emulsion, producing a far better signal: background ratio than Kodak D19. A pretreatment in aurous thiocyanate for 4 min before development in D19 A/S for 4 min at 291 K increased the signal: background ratio by 200% compared with ordinary development in Kodak D19.When gold latensification was used with D19 developer, the signal was increased, but no more than with D19 A/S, and the gain was offset by the intense background that resulted.
Analysis of the spatial organization of the cell: a statistical method for revealing the non‐random location of an organelle
Authors: Hemon Denis , Bourgeois Claire A. , Bouteille Michel 
Published: August 2011

SUMMARYA method is proposed for testing the randomness of the location of an organelle within a given area of a cell section. The approach chosen is to analyse the distance between this organelle and a specific point considered as a point of reference. The method consists of converting this distance into the ratio of one given area to another and comparing the statistical distribution of the converted values to the uniform distribution. This method has the advantage of being valid in the absence of any restrictive assumptions concerning the heterogeneity in size and/or shape of the collection of sections sampled. Detailed examples are given to illustrate the practical use of the method, and its possible extensions are discussed.
An electron diffraction study of paramylon storage granules from Euglena gracilis
Authors: Booy F. P. , Chanzy H. , Boudet A. 
Published: August 2011

SUMMARYParamylon storage granules from Euglena gracilis were characterized by electron diffraction techniques using electrons of various accelerating voltages: 2 MV for the thick granules and 100 kV for the thinner ones. Intact granules gave well resolved, characteristic (1→3)‐β‐d glucan fibre diffraction diagrams with the glucan molecular orientation parallel to the longer axis of the granule. Hydrated electron diffraction patterns with better resolution were obtained from thinner granules by examination at low temperatures of quench‐frozen specimens. In this case, the pattern indexed on an hexagonal system with a = b= 1·55 + 0·01 nm and c (fibre axis) = 1·86 ± 0·01 nm. Sections of embedded granules provided single crystal‐like electron diffraction patterns corresponding to various sections of the reciprocal lattice of (1→3)‐β‐d glucan (including the hko section). Finally, by scanning electron microscopy, it was shown that the granules swell on contact with water and take up a characteristic ribbed, pumpkin‐like shape.
Ice crystal damage in frozen thin sections: freezing effects and their restoration
Authors: Frederik P. M. , Busing W. M. 
Published: August 2011

SUMMARYThin sections of unfixed kidney, fast frozen without cryoprotectants, were fixed in osmium tetroxide vapour directly after freeze drying or after 30 min in a moist atmosphere. Dry sections fixed in vapour showed ice crystal damage characteristic for the freezing procedure. This was demonstrated with freeze fracture replicas from the same preparation. Ice crystal holes were obscured in serial sections which were freeze dried and allowed to rehydrate in a moist atmosphere. The same ultrastructural appearance was observed in frozen sections brought to room temperature immediately after cutting. Frozen thin sections from unfixed tissue, if freeze dried, are very sensitive to atmospheric conditions and need some form of stabilization (e.g. osmium vapour fixation, sealing with an evaporated carbon film) before electron microscope images can be interpreted as representative for the frozen state. Restoration of ice crystal damage can occur by melting frozen sections or by rehydration of freeze dried frozen sections. Restoration phenomena will impair studies aimed at the localization of diffusible substances by autoradiography or X‐ray microanalysis.