bluuebunny/crossref_metadata_2025 huggingface dataset:
SEM analyses of cathodoluminescence in MgO, CdS and GaAs/GaxAl1–xAs crystals
Authors: Datta S. , Aeberli K. E. , Boswarva I. M. , Holt D. B.
Published: August 2011

The method of analysis developed for the study of cathodoluminescence in the scanning electron microscope is briefly outlined. Current studies of cathodoluminescence in three types of crystal are presented. These are: (1) deformed and annealed MgO, (2) CdS into which Ga has been diffused, and (3) double heterostructure GaAs/GaxAl1–xAs laser material.
Diffusible ion localization by ion microscopy: a comparison of chemically prepared and fast‐frozen, freeze‐dried, unfixed liver sections
Authors: Stika Katherine M. , Bielat Kenneth L. , Morrison George H.
Published: August 2011

The necessity of low temperature preparative procedures for diffusible ion localization using the ion microscope has been established with rat liver as the test material. Using conventional fixation procedures, significant ion loss and redistribution were observed which exceeded the 1 μm lateral resolution of the direct imaging ion microanalyser. The compositional morphology evidenced in chemically prepared versus fast‐frozen, freeze‐dried, unfixed material was compared and evaluated in terms of ion retention, ion redistribution and morphological integrity. A mass spectral analysis of both preparations has been presented and discussed with regard to spectral interferences and elemental sensitivities. Ion images of sodium and potassium were recorded for chemically prepared liver sections and compared with the ion distributions obtained for unfixed, fast‐frozen, freeze‐dried 1 μm thick sections. The magnitude of ion loss during preparation of samples removed at different stages in the course of chemical processing was determined by atomic absorption and flame emission spectrophotometry.
Determination of the mean caliper diameter of lung nuclei by a method which is independent of shape assumptions
Authors: Woody Dawn , Woody Erik , Crapo James D.
Published: August 2011

When determining the number of nuclei (therefore cells) present in a known volume of tissue it is necessary to determine the overall mean caliper diameter of nuclei for each cell type studied. Most previous methods for determining the mean caliper diameters (D̄) of cell nuclei were strongly dependent upon assumptions of the shape of the particles in question (Greeley et al., 1978). A computer program has now been designed to calculate D̄ from three‐dimensional reconstructions of nuclei in a manner that is independent of all shape assumptions. The D̄s of ten capillary endothelial cell nuclei from normal rat lungs have been determined by this shape‐independent method. The resulting overall mean caliper diameter for this group of ten nuclei varied only slightly from that previously estimated for them by a method which assumes them to be triaxial ellipsoids. In a similar comparison, the D̄s for ten normal human lung endothelial cell nuclei were determined by both methods. The overall mean caliper diameter determined by the shape‐independent method was 10% larger than that estimated by the shape‐dependent method. This suggests that human lung endothelial nuclei vary significantly from the shape assumption (triaxial ellipsoid) employed in the shape‐dependent method, and the shape‐independent method was considered to yield a more accurate measurement of D̄.
Scanning electron microscopic examination of the scolex and external tegumental surface of Proteocephalus ambloplitis
Authors: Jilek Reid , Crites John L.
Published: August 2011

This examination represents the first scanning electron microscopic study of a proteocephalid tapeworm, Proteocephalus ambloplitis, and it also serves as the first comparative study between the adult and larval stages of a tapeworm. Proteocephalus ambloplitis has numerous microtrichs whose densities and diameters differ greatly from those of cyclophyllidean and pseudophyllidean tapeworms previously examined. Proteocephalus ambloplitis also has an external apical organ and a subcuticular organ.
Differential sensitivity of neurosecretory and non‐neurosecretory neurones of an aphid to sucrose during fixation for electron microscopy
Authors: Hardie Jim
Published: August 2011

The Group 1 neurosecretory cells and a proportion of the non‐neurosecretory cells in the protocerebrum of the aphid Megoura viciae show gross differences in preservation when sucrose is used to increase the osmolarity of a glutaraldehyde primary fixative and an osmium tetroxide secondary fixative. The neurosecretory cells are well preserved whilst a proportion of the non‐neurosecretory cells are shrunken and electron dense, the proportion of affected cells increases with the concentration of sucrose used. This difference is not seen when either the primary or the secondary fixatives are used alone, when a mixture of the primary and secondary fixatives is used or when the osmotic pressure is increased with inorganic salts.
A pellet mould for bulk specimen X‐ray microanalysis in SEM
Authors: Bistricki T.
Published: August 2011

The paper describes a mould that allows pellet making of powdered specimens for X‐ray microanalysis. The pellet is formed directly on a specimen support stub. Technical drawings provide necessary information for a machine‐shop reproduction.
The observation of amorphous materials at high voltage and high resolution
Authors: Smith David J. , Saxton W. O. , Cleaver J. R. A. , Catto C. J. D.
Published: August 2011

Thin films of amorphous carbon, silicon and germanium have been examined at high resolution at accelerating voltages up to 575 kV with the Cambridge University high resolution electron microscope. The directly interpretable resolution has been demonstrated to extend to 0ṁ22 nm, so that the microscope is capable of providing unambiguous structural information at the atomic level. The observations of both carbon and silicon were, however, somewhat disappointing in that no significant specimen detail was revealed despite the improved performance compared with that of conventional 100 kV instruments. Some of the factors involved in observation and interpretation of these images are discussed.
Preliminary electron microscopical observations of defects in cold rolled amorphous Cu60Zr40
Authors: Chevalier J. P.
Published: August 2011

Amorphous Cu60Zr40 alloy, prepared by a levitation melt and double roller quenching technique has been severely cold rolled. Preliminary observations show the presence of two kinds of defects with different morphologies. In both cases the defects have a contrast which corresponds to that for a lower projected atomic density at the defect.
Investigations of the structure of amorphous and partially crystalline metallic alloys by high resolution electron microscopy
Authors: Gaskell P. H. , Smith David J.
Published: August 2011

A number of amorphous and partially crystalline palladium‐silicon alloys have been examined by high resolution transmission electron microscopy at 500 kV. With the directly interpretable resolution extending beyond the first peak in the structure factor at 0ṁ23 nm, details of the local microstructure at the atomic level are visible. Images of small metallic particles show a well‐defined pattern of fringes over local regions. In some instances, especially in partially‐ordered alloys, neighbouring or overlapping fringe patterns appear to be orientationally‐related in a similar manner to fringe systems seen in symmetrically multiply‐twinned particles. The significance of this type of structural examination for amorphous metals is discussed.
Fast computational procedures for the simulation of structure images in complex or disordered crystals: a new approach
Authors: Dyck D. Van
Published: August 2011

Despite the important contribution of high‐resolution electron microscopy to materials science, the use of computer simulation as a reliable tool for the interpretation of the structure images in complex crystals or disordered solids has been limited seriously by the high computer demands of the available computational techniques.
Some ordering phenomena in the β Cu4Ti phase
Authors: Ecob Roger C. , Bee John V. , Ralph Brian
Published: August 2011

This paper presents further evidence concerning the structure of the β phase which forms as Widmanstätten or cellular precipitates in dilute copper‐titanium alloys. The effect of deformation in producing faults in this ordered phase is considered, and illustrations are provided of the resultant dislocation structures. The observation of some intrinsic disorder is discussed in terms of the influence of a simultaneous phase transformation on the order‐disorder transition.
The analysis of a defect in ordered Ag3Mg
Authors: Portier R. , Gratias D. , Guymont M. , Stobbs W. M.
Published: August 2011

The high resolution image of an apparently displacive defect in the long period ordered structure of Ag3Mg is analysed in terms of a simplified substitutional model. It is demonstrated by image simulation that the characteristics of the image could be described equally well on the basis of progressive relative substitution of Ag for Mg on two of the four sublattices in the structure.
High resolution imaging of defects in sigma phase in a stainless steel
Authors: Southwick D. , Stobbs W. M.
Published: August 2011

The high resolution axial lattice imaging technique has been applied to the study of the faults which commonly occur in the sigma phase which can be formed from ferrite in a duplex high chromium stainless steel on ageing at 973 K. It was noted that axial lattice fringe images at (001)σ show no detailed correspondences with thickness and it was further demonstrated that lattice fringe displacements in axial images at strain free boundaries can be used to give an accurate measure of the magnitude of the associated lattice displacements. The displacement vectors associated with the common (100)σ faults in the material were classified.
Intermediate transformation structures in silicon carbide
Authors: Jepps N. W. , Page T. F.
Published: August 2011

In order to examine the detailed structural origins of the confusing diffraction patterns often exhibited by partially transformed polytypic materials, HREM lattice imaging techniques have been used to examine directly the layer‐by‐layer stacking sequences in a range of samples of cubic (β) SiC partially transformed to α polytypes by high temperature annealing. A number of intermediate structures have been characterized, one of which provides the first direct evidence supporting an earlier model of the β→α transformation (Jagodzinski, 1971) in which three‐layer twins, separated by multiples of three layers, propagate through the cubic structure to produce a faulted haxagonal (6H) polytype. These observations, together with considerations of twin geometry, also suggest a means of co‐ordinating the sideways nucleation of 6H unit‐cell high steps, whose lengthways growth has been previously observed to effect the solid‐state β→α transformation (Jepps & Page, 1979).
Using RHEED to study polytypism
Authors: Gauthier J. P.
Published: August 2011

Up to now, relatively few papers have dealt with electron beam investigations of polytypic substances. Recent work in SiC (Gauthier, 1978) pointed out the general interest in the use of reflection high energy electron diffraction (RHEED) for examining well‐ordered long‐period modifications. The main results are summarized here, showing what information can be obtained from RHEED patterns for the determination of polytype structures and hence possible explanations of growth mechanisms. In the same way, other materials have now been examined by the same technique and some results from zinc sulphide crystals are presented as an illustration. The mixtures of different ZnS modifications are complex; moreover, polytype disorder exists commonly in that substance. Such a situation vindicates the use of other techniques, particularly high resolution electron microscopy.
Structure‐staining relationships in histochemistry and biological staining
Authors: Horobin RichardW.
Published: August 2011

A description is given of the choice, rationale and calculation of several numerical coefficients for describing the chemical structures of staining reagents such as dyestuffs, enzyme substrates, diazonium and tetrazolium salts. Using such coefficients, structure‐staining correlations may be made for many staining systems. Examples include the structural correlations of the quantitative affinity measurements of the staining of chromatin with basic dyes, the tetrazolium salts for use as visualizing agents in enzyme histochemistry, and the use of bis‐azo compounds as acid or basic dyes, or as fat stains. The value of such structure‐staining correlation models for assisting the rational selection and design of new histochemical reagents, and for understanding old reagents and procedures, is discussed.
Structure‐staining relationships in histochemistry and biological staining
Authors: Horobin RichardW. , Flemming Linda
Published: August 2011

Correlations between the structural features of dyes and staining performance for elastic fibres were investigated. Dyes studied included the traditional stains (such as Gomori's Aldehyde‐Fuchsin and Weigert's Resorcin‐Fuchsin), acid dyes used from alkaline aqueous‐organic solvent mixtures (the Horobin‐James system), and basic dyes used from acidic aqueous‐ethanolic mixtures (the Taenzer‐Unna system). In all three classes effective elastic fibre stains had large conjugated bond numbers, and were often hydrophobic (i.e. had high Hansch π values). By choosing dyes with conjugated bond numbers at or over a critical value (25 for the TU system, 35 for the HJ) it is possible to select new and effective dyes for use in the HJ and TU staining systems. Mechanistically these results support the view that for typical commercial dyes and also for the traditional stains van der Waals attractions provide the important contributions to dye‐elastic fibre affinities, with hydrophobic bonding playing a subsidiary role. However, supporting the views of Lillie, it was also noted that even hydrophilic dyes of low conjugated bond number could stain elastic fibres, if the dye carried a sufficiently reactive primary amino group as a substituent. The additional substituent groupings needed to generate such reactivity have been specified, for both acidic and alkaline reaction conditions.
The molecular biology of histochemical staining by cationic phthalocyanin dyes: the design of replacements for Alcian Blue
Authors: Scott J. E.
Published: August 2011

Four cationic copper phthalocyanin dyes are compared with Alcian Blue 8G for specificity of interaction with a range of natural and synthetic polyanions. The CEC system is used to estimate dye‐substrate affinities.

The results support the hypothesis that the tissue staining pattern of Alcian Blue is determined by (a) exclusion of the dye from polynucleotide stacked base pairs by steric hindrance due to bulky substituents on the chromophore and (b) the presence of pendant quaternary charges whose affinity for negative sites on polyanionic substrates is without regard for the precise chemical nature of the anion.

These conclusions, and practical considerations lead to the choice of quaternized Astra Blue 6GLL as a replacement for Alcian Blue (now no longer manufactured).

It is superior to Alcian Blue in pH range, and stability in solution. It is easily prepared from a readily available precursor.
On the mechanism of Mallory's phosphotungstic acid‐haematoxylin stain
Authors: Puchtler Holde , Waldrop FayeSweat , Meloan SusanN.
Published: August 2011

The mechanism of Mallory's (1900) phosphotungstic acid‐haematoxylin (PTAH) stain is not yet fully understood; staining properties vary with the age of the dye solution. In this study, a 1‐year‐old solution was employed as described previously. Paper chromatograms revealed blue, red and yellow components of phosphotungstic acid‐haematoxylin. Modification of reactive groups as well as consecutive treatment of sections with haematoxylin and phosphotungstic acid indicated hydrogen bond formation by the blue component. Substitution of brazilin for haematoxylin proved that two free phenolic ‐OH groups per dye residue are essential for binding of the blue phosphotungstic acid‐haematoxylin chelate. Uptake of the red fraction was determined by the polyacid moiety of the dye. Van der Waals forces presumably contributed to dye binding, but did not govern the selectivity of the red and blue components of PTAH for various tissue structures.
Erythrocyte membrane topo‐optical staining reflects glycoprotein conformational changes
Authors: Geyer Günther , Makovitzky Josef
Published: August 2011

The 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

A 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

A 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

A 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

The 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.
The preparation of fragile protoplasts for electron microscopy
Authors: Seed L. J.
Published: August 2011

A method is described whereby highly fragile protoplasts may be successfully prepared for electron microscopy.
Optical diffraction: applications to lamellar microstructures
Authors: Andrews K. W. , Keown S. R.
Published: August 2011

Optical 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

A 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

This 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

Behaviour 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

Matching 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

Using 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

Samples 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

Halite (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

The 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

This 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

The 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

The 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

Gold 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.
A general‐purpose microcomputer program for stereological data collection and processing
Authors: Briarty L. G. , Fischer P. J.
Published: August 2011

The paper describes a program, written in BASIC and designed to run on a microcomputer, to collect and process point‐counting stereological data. It allows flexible equation construction using basic stereological formulae.
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

A 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

Paramylon 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

Thin 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.
Adaptation of a low‐power stereomicroscope to scan cell colonies labelled with fluorescein isothiocyanate
Authors: McMahon James B. , Iype P. Thomas
Published: August 2011

A stereomicroscope was modified for use in visualizing fluorescence‐labelled cell‐colonies at low magnifications. A xenon lamp and an FITC filter (Zeiss) were used to obtain exciting radiation to illuminate fluorescent‐labelled specimens. The system is precise enough to distinguish between normal and cancer cell‐colonies after specific interaction with FITC‐conjugated antiserum.
An improved technique for the freeze‐fracture of cell cultures grown as monolayers
Authors: Umrath W.
Published: August 2011

An improved and rapid procedure for the freeze‐fracture of cell cultures grown as monolayers is described. No additional equipment than normally used for freeze‐fracturing is necessary and cell culture conditions are as usual on plastic dishes. Cells are grown on a plastic foil membrane so that they can be viewed with a light microscope. If necessary, while viewing with a binocular microscope, specimen holders are glued to the foil membrane over selected areas of the culture. The specimen holders with the attached cell culture are dissected out and processed for freeze‐fracturing in a BIOETH 2005. Fracture planes occur along the cell surface as well as through entire cells. Analysis of corresponding fracture faces is possible.
Vicia faba root slices examined after freeze‐fracture and thaw‐fixation
Authors: Haggis G. H.
Published: August 2011

Vicia faba root slices have been frozen, fractured and thawed into fixative, to give a deep view into cell cytoplasm and into cell organelles. Fracture through interphase nuclei shows a tangle of 20–25 nm chromatin as well as finer strands. The nucleoli appear very compact. The proplastids in these preparations are packed with starch grains. In fracture through smaller organelles, probably mitochondria, 10–12 nm strands are seen which may correspond to organelle DNA in supercoiled form. Strands of this dimension, as well as finer strands, are also seen in preparations of isolated leaf chloroplasts after freeze‐thaw lysis.
The design and use of a simple device for rapid quench‐freezing of biological samples
Authors: Handley Dean A. , Alexander Jack T. , Chien Shu
Published: August 2011

The detailed design of a simple device for rapid quench‐freezing of biological samples under reproducible conditions is presented. With spring‐augmented descent, sample immersion velocity of 10 m s−1 into a cryogenic liquid is achieved. Biological samples, loaded in Balzers planchets, Denton holders, or a newly designed ‘titanium envelope’, are suitable for rapid‐freezing with this device. Using 4 μm titanium foil, light weight (1 mg) streamlined holders can easily be made to enclose cell suspensions or tissue samples. The foil envelope is designed for efficient heat dissipation while protecting the sample from possible impact or flow distortions occurring from spring‐augmented immersion. Human erythrocytes, quench‐frozen in the titanium envelope, were prepared for electron microscopy by the freeze‐substitution technique. Two opposing 25–30 μm surface zones were frozen in the apparent absence of ice. The extended depth of cryofixation is attributed to the advantages of thin foil in the titanium envelope design and the use of rapid‐immersion technique.
Polyvinyl alcohol coating: an improvement of the freeze‐fracture technique
Authors: Brown Dennis
Published: August 2011

A modification of the freeze‐fracture technique, involving the coating of tissues with polyvinyl alcohol (Vinol) prior to freezing, is described. This results in substantial improvements over the more conventional method in which material is cryoprotected and frozen in buffered glycerol alone. The high vacuum is produced more rapidly and can be better than in the absence of vinol and the speed of replica recuperation is greatly increased.
Estimation of surface labelling on whole, critical point dried, cells by microprobe analysis in the scanning electron microscope
Authors: ap Gwynn I.
Published: August 2011

A method is described whereby the relative amount of histochemical label, such as ferritin, provided it is exclusively attached to the surface of cells, can be estimated. The X‐ray emission from the metal coating, deposited from a diode‐sputter coating unit, is used to correct for the variations in the iron counts from the label which could occur due to changing analysis conditions.
Microdensitometry with image analyser video scanners
Authors: Jarvis L. R.
Published: August 2011

A numerical method for calibration of the Quantimet 720 1D Auto detector as a densitometer in absolute density units has been developed and applied to integrated microdensitometric measurement. A procedure for the estimation and correction of microscope glare error has also been derived. The error after glare correction was found to be comparable with threshold setting variation encountered in routine use of the Quantimet.

The method should prove valuable in densitometric applications not only for Quantimet image analysers but also for any instrument employing a video imaging system because the underlying principles are the same.
The use of spectroscopic film for fluorescence microscopy
Authors: Skaer R. J. , Flemans R. J.
Published: August 2011

A spectroscopic film, Eastman Kodak 103a‐F, is particularly suited to the photography of fluorescent specimens in the microscope, especially when the light emitted is dim, or high magnification is needed.
On the relative efficiencies of alternative ratio estimators for morphometric analysis of cell membrane surface features
Authors: Mayhew T. M.
Published: August 2011

For morphometric analysis of desmosomes, synapses and other membrane surface features, estimating component densities on a reference surface (the membrane with which they are associated) often provides a useful practical alternative to estimating densities in a reference volume (the tissue in which they are enclosed). The present report assesses the relative efficiencies of these two approaches. In particular, the efficiencies of stereological estimators for component numerical density on a surface (Ns) and in a volume (Nv) are compared, together with those for the surface densities Ss and Sv.

For this purpose, a morphometric model developed for characterizing desmosomes in human forearm skin was quantified by point and intersection counting. The efficiencies of the alternative ratio estimators were evaluated by comparing their coefficients of variation obtained on samples of equivalent size and having a similar overall analysis time. Various types of bias influencing the results are also discussed.

The results demonstrate that estimators of component densities on a surface are superior to those of densities in a volume when studying epidermal desmosomes. For a given size of sample they offer a smaller coefficient of variation. In other words, they are more efficient. They may be even more advantageous in other experimental situations.