bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐resolution scanning electron microscopy of the surface of red blood cells
Authors: Clarke J. A. , Broers A. N. , Salsbury A. J. 
Published: August 2011

SUMMARYExamination of normal human red blood cells with a high (2.5 nm) resolution scanning electron microscope revealed a definite surface pattern. The pattern was slightly more pronounced in specimens dried in air after fixation than in those dried by the critical‐point method. There was a radial arrangement of filament like elevations at the periphery of the red cell and a more reticular pattern to wards the centre of the cell. The appearances probably represented a network of elenin fibres lying just under the surface of the red cell.
Visualization of collagen cross‐banding in the scanning electron microscope
Authors: Finlay J. B. , Hunter J. A. A. 
Published: August 2011

SUMMARYMicrographs are presented to show that the characteristic molecular cross‐banding of human dermal collagen can be visualized in the scanning electron microscope. The specimen‐preparation technique used is described together with a discussion of the various conditions necessary for the visualization of the cross‐banding.
The preparation of field‐ion‐microscope specimens containing grain boundaries
Authors: Papazian J. M. 
Published: August 2011

SummaryA back polishing technique has been devised which increases the efficiency of a field‐ion‐microscope study of grain boundaries. The rate of back polishing is predicted from the relationship dmd = 2·5 × 104 nm2/msec. This relationship is shown to be valid experimentally and theoretically. Its validity implies the persistence of constant current density conditions during electropolishing of sharp, needle‐shaped specimens down to diameters of 100 nm.
Dark‐field electron microscopy of unstained and unshadowed DNA*
Authors: Haydon Glen B. , Lemons Ross A. , Clayton David A. 
Published: August 2011

SummaryThe vastly increased contrast made possible by tilted‐beam dark‐field electron microscopy enables strands of DNA prepared by the Kleinschmidt technique to be clearly imaged without the heavy‐metal staining or shadowing usually required. This technique is applicable over a wide range of magnifications and is easily accomplished with several commercial instruments.
Vermiculite lamellae as substrates for transmission electron microscopy
Authors: Manley J. H. , Williams D. L. , Okinaka R. 
Published: August 2011

SummaryChemically exfoliated vermiculite has been investigated as a specimen‐support film for electron microscope. The thinnest lamellæ obtained appear to be less than 1 μg/cm2 (∼4 nm) thick, have low electron noise and show good stability in the electron beam. Their surface is smooth and hydrophilic and phase texture is low.
The use of polarized light microscopy in examining the structure of carbon fibres*
Authors: Knibbs R. H. 
Published: August 2011

SummaryThe structure of carbon fibres has been examined using the optical microscope. Three types of fibre structure have been identified which differ in the orientation of the graphite crystallites within the transverse plane, the type of precursor can be identified by the shape of the carbonized fibre. The particular type of structure is determined by the process conditions which the fibre has undergone. Subsequent heat treatment merely enhances the crystallite alignment of the structure without altering the direction of preferred orientation.
An improved microspectrofluorimeter with automatic digital data logging: Construction and operation
Authors: Rost F. W. D. , Pearse A. G. E. 
Published: August 2011

SUMMARYThis paper describes an instrument for microspectrofluorimetry, based on the Leitz microspectrograph. Important features are monochromatic epi‐illumination, a reference channel and a measuring system using photon counting with automatic recording of data in digital form. To minimize fading, measurements of fluorescence intensity can be made within as little as 200 msec from the commencement of irradiation.
Some microscopic aspects of the mild wear of steel*
Authors: Quinn T. F. J. 
Published: August 2011

SUMMARYThe paper reviews the experimental classifications of the unlubricated sliding wear of metals, together with some of the suggested relationships between the wear rates, the real area of contact, the load, the hardnesses of the metals and the probability of producing wear particles at the real areas of contact. The microscopic nature of the interactions between sliding surfaces is discussed, with special emphasis on the advantages (and limitations) of using electron microscopy for studying these interactions, and the importance of using X‐ray diffraction techniques to complementthe electron microscopy.Examples are then given of how the use of electron microscopy has revealed many facets of the mild wear of steel which would not otherwise have been suspected. For instance, the areas of contact between sliding steel surfaces are comparatively large and few in number, in contradistinction to the situation occurring in stationary contact. These large contact areas crack in a characteristic fashion reminiscent of fatigue failure or brittle fracture. They then flake off at a critical thickness (∼ 10−4cm) to provide the source for the wear debris. The wear debris collects initially in the rough regions which are left behind when the flakes become detached. In this position, the wear debris probably acts in an abrasive fashion.Eventually, the wear debris is thrown clear of the contact area. Analysis of this debris using X‐ray diffraction techniques has shown that there is a strong correlation between the presence of certain oxides in the wear debris and the severity or mildness of the wear. It has also been used to estimate the temperatures occurring between the areas in sliding contact. This estimate is consistent with previously published dynamic thermocouple measurements. It also gives rise to consistent values of the activation energy required for oxidation during wear.
Metal oxide structure investigated using a variety of light‐ and electron‐microscopical techniques*
Authors: Fursey Anita 
Published: August 2011

SUMMARYSpecial techniques for examining the same specimen area of metal oxides with different instruments, for example light microscopy and scanning electron microscopy of identical features are described. Transmission electron microscopy and diffraction on stripped oxide films have been augmented by electron‐probe microanalysis both in a conventional microanalyser and in a combined electron‐microscope microanalyser EMMA‐4. Examples of scanning electron microscopy of oxidized sheet‐metal specimens and stripped films are given and probe analysis in the Stereoscan is illustrated. High‐voltage electron microscopy of oxide nodules reveals additional detail. Techniques for examining thick oxide scales are also described. The illustrations are taken from the oxidation of iron 10% chromium alloy at 500−600°C in air.
Electron‐microscope preparation techniques applied to the light microscopy of the cambium and its derivatives in Pinus radiataD. Don.
Authors: Barnett J. R. 
Published: August 2011

SUMMARYEpon 812 was used successfully as an embedding medium for the preparation of the secondary meristem and its derivatives in Pinus radiata for light microscopy. Specimens were fixed in glutaraldehyde followed by osmium tetroxide solution, using a schedule developed for the electron microscopy of these tissues. Sections from 2 to 5 μm thick were cut using an LKB Ultratome III and glass knives. Sections were evaluated without prior removal of the embedding medium using bright‐field, phase‐contrast and interference‐contrast microscopy. Results for cambium were generally superior to those obtained by using the conventional fixatives for light microscopy and paraffin embedding. The advantages and disadvantages of this technique are discussed and it is concluded that the use of Epon for embedding this type of material is easier and gives better results than older established methods. It is suggested that methods of electron microscopy be considered when the preparation of a material for light microscopy has proved difficult or impossible by other means, or when particularly thin sections are required.
Capillary‐tube units for individual block preparation in light and electron microscopy*
Authors: Galey Frank R. , Dunn Robert F. 
Published: August 2011

SUMMARYShort lengths of 4‐mm capillary tubing are fitted with teflon caps for processing individual blocks in preparation for light‐ and electron‐microscopic observation. The processing units hold a nickel mesh grid to prevent tissue loss. Advantages include: (1) the ability to process very small blocks otherwise lost during processing; (2) separation of tissue from specifically mapped areas; (3) conservation of processing fluids and time.For routine tissue dehydration and infiltration, it is generally possible to process many tissue blocks collectively. However, instances frequently occur in which it is necessary to treat individual blocks separately. Examples include processing of single muscle fibres, and individual sensory regions where it is desirable to separate various segments of the sensory organ.This paper describes specially prepared capped capillary tubes for the purpose of individual block preparation. These containers are advantageous in conservation of fluids, ease of specimen transfer, and most importantly strict isolation of the individual blocks of tissue.
The effect of radio‐frequency sputter ion etching and ion‐beam etching on biological material: a scanning electron microscope study
Authors: Hodges Gisele M. , Muir Marjorie D. , Sella C. , Carteaud A. J. P. 
Published: August 2011

SUMMARYMammalian and avian cells have been examined in the scanning electron microscope either after prior radio‐frequency sputter ion etching with different ions (hydrogen, helium, argon, oxygen) or after argon ion bombardment in the SEM. Whilst the pattern of erosion is similar in the different specimens, the etching pattern varies with the different gases. It has not been possible to relate the etching patterns to characteristic subsurface structures.
Evidence against through‐section thawing whilst cutting on the ultracryotome
Authors: Hodson Stuart , Marshall John 
Published: August 2011

SUMMARYWe present evidence that ultrathin frozen sections cut on the ultracryotome only partially thaw during the cutting action. This conclusion is derived from calculations of the loss of mechanical energy as the specimen strikes the knife. The mechanical energy is assumed to be completely transformed into heat which warms the freshly cut section.
Field‐ion microscopy in colour using multiple imaging gases
Authors: Schubert C. C. 
Published: August 2011

SUMMARYWhen channel plate intensification methods are used in field‐ion microscopy, image gases other than hydrogen and helium give bright images easily photographed with colour film. Since different phases in the specimen image differently with differing gases, colour photography through filters yields micrographs which accentuate these phase differences.
The use of silver nitrate as a stain for scanning electron microscopy of arterial intima and paraffin sections of kidney
Authors: Geissinger H. D. 
Published: August 2011

SUMMARYThe suitability of silver nitrate as a stain for scanning electron microscopy was investigated. Accordingly en face preparations of arterial intima were impregnated with silver nitrate, fixed with formalin, and coated with platinum‐palladium alloy. In SEM images, the silver lines surrounding the endothelial cells, and the deposits on the intima appear as white lines or dots on a darker background. Similar results were noted for nitrocellulose‐embedded endothelium. Paraffin sections of kidney treated with silver nitrate (von Kossa's stain) were also examined. Deposits of the calcium salts of phosphates and carbonates (stained with silver nitrate) were easily differentiated from other tissue components. Results were compared with those obtained with the light microscope. The scanning electron microscopic examination provided a finer definition of the silver granules relative to the surrounding architecture. The limitations and advantages of these techniques and possible further applications of silver nitrate as a stain for scanning electron microscopy are discussed. The use of silver nitrate as a stain for some SEM preparations is recommended.
A three‐dimensional model of membrane ruffling from transmission and scanning electron microscopy of cultured monkey kidney cells (LLCMK2)*
Authors: Price Zane H. 
Published: August 2011

SUMMARYThree‐dimensional models of ruffling membrane were constructed by assembling enlarged Styrofoam duplicates of serial sections. The serial sections were taken from a cultured monkey kidney (LLCMK2) cell and were cut at right angles to the plane of the substrate. Various features of the models were corroborated by scanning electron microscopy.
The problem of paired spheres and of straight chains of spheres in slices or polished sections
Authors: Hennig August 
Published: August 2011

SUMMARYThe starting point is the problem of finding the percentage q2 of paired nuclei in liver cells, when the percentage p2 of twin cuts in slices is known. The general solution for unequal spheres becomes most simple for equal spheres and leads to an extrapolation for endless straight chains of equal spheres, at first for closed and then for open series with constant intervals. Three total sums of endless series of fractions are a welcome mathematical extra.The microscopist will prefer instructions which are generalized from counts in final rows of spheres. With them he can analyse the composition of a mixture of limited chains, with different numbers of spheres.
Interference microscopy of polymer fibres*
Authors: Pluta M. 
Published: August 2011

SUMMARYThe paper describes the use of a double refracting interference microscope with variable amount and direction of wavefront shear for the study of synthetic polymer fibres. General theoretical aspects of the field of the differential interference contrast method, and practical problems related to the application of this method in fibre examination are discussed. Some improvements in the micro‐interferometric measurement of the birefringence and refractive indices of fibres are suggested. Advantages of the developed double refracting interference microscope with variable wavefront shear are discussed from the point of view of fibre microscopy, and illustrated by photomicrographs.
Fracture faces of the tonoplast in root tips after various conditions of pretreatment prior to freeze‐etching
Authors: Fineran B. A. 
Published: August 2011

SUMMARYRoots grown in glycerol and frozen‐etched show fracture faces of the tonoplast covered with particles having a density distribution on face A different from that on face B. In contrast, roots prefixed in glutaraldehyde prior to freezing show tonoplasts either with particle populations comparable to those in frozen living cells, particles interspersed with plaques, plaques only, or surfaces devoid of both particles and plaques. Membranes with plaques are the most frequently found. Plaques occur as slightly raised structures and with approximately equal frequency on faces A and B of the tonoplast. Other membranes of the cell seldom show plaques and resemble those of unfixed roots. Plaques occur independently of the concentration of glutaraldehyde or glycerol, the stage at which buffer is added during the schedule, and whether fixation is simultaneous with glycerination or followed by glycerination. It is argued that plaques are the result of contamination during etching rather than being due to an alteration in the plane of fracturing. It would appear that prefixation enhances the formation of plaques by altering the properties of the tonoplast so that the membrane acts as a site for the selective condensation of contaminant material.
A preliminary field‐ion microscopic study of a Co‐Ti alloy
Authors: Davies D. M. , Ralph B. 
Published: August 2011

SUMMARYA study has been made of the initial stages of decomposition of a supersaturated solid solution of a cobalt alloy containing 7·5 atomic percent titanium. It is shown that the initial precipitation of Co‐Ti is periodic (along < 100 >) and that spacings and sizes measured by field‐ion microscopy agree well with those measured by transmission electron microscopy and from ‘sidebands’ on X‐ray diffraction photographs. The experimental conditions under which contrast between the precipitate and matrix may be obtained are discussed.
A method for quantifying electron staining, obtaining the dry specific gravity of specimens in sections, and measuring section thickness
Authors: Casley‐Smith J. R. 
Published: August 2011

SUMMARYMethods are described for the estimation of the dry specific gravities (SG) of specimens in thin sections, especially for the comparison of one group with another and for the quantification of electron stains. Variations in section thickness are overcome by using the naked supporting film as a base‐line, and relating the SG of the specimen to that of the resin, which acts as a standard. Section thicknesses may also be estimated by using similar methods. The optical densities of their images are compared with those of standards; knowledge of the SG of the resin allows one to calculate its thickness.
An inexpensive device for increasing the usefulness of the comparison eyepiece in examining slide‐mounted ectoparasitic insects
Authors: Pilgrim R. L. C. 
Published: August 2011

SUMMARYConstruction and use are described for a stand to enable either or both microscopes to be rotated while examining pairs of specimens through a comparison eyepiece. The device facilitates accurate orientation of the images, enabling rapid and critical detection of similarities or differences between them.
The Biomicroscope and Vickers image splitting eyepiece applied to the diurnal variation in human central corneal thickness
Authors: Gerstman Daniel R. 
Published: August 2011

SUMMARYTo summarize, it is found that the human cornea thins approximately 7% throughout the waking hours in air. Assuming the corneal constants given by Gullstrand for his schematic eye No. 1, a 7% decrease in corneal thickness would represent a decrease of only 0·00385 diopters in the refractive power of the human cornea.
Reduction of polymer growth in electron microscopes by use of a fluorocarbon oxide pump fluid
Authors: Ambrose B. K. , Holland L. , Laurenson L. 
Published: August 2011

SUMMARYA commonly experienced contamination problem in electron microscopes is the growth of electron induced polymer films on the electrodes and specimens in instruments evacuated by oil pumps. Hydrocarbon fluids are generally used in the vacuum pumps and experiments have been made to reduce the contamination rate in a transmission instrument (AEI 802) by using fractional distillates of a new fluorocarbon oxide compound. The rotary pump was replaced by one charged with a fluorocarbon oxide lubricant and the fluid charge in the diffusion pump replaced by a fluorocarbon oxide evaporant. Both specimen and electrode contamination were greatly reduced by the use of the new fluid. Electron micrographs of a gold film are shown comparing contamination levels produced in organic and fluorocarbon oxide atmospheres after prolonged exposure to the electron beam.
The stereology of projected images
Authors: Underwood Ervin E. 
Published: August 2011

SUMMARYA generalized, geometrical approach is adopted in reviewing the basic relationships of projected structures. Projections of features from a plane to a projection line, and from a three‐dimensional foil to a projection plane are considered briefly. The relationships that apply to apparent and total projections are next assembled for lines, surfaces and bounded regions. The properties of convex bodies, the geometrical attributes, and the related projected quantities are enumerated. The inter‐relationships of important microstructural parameters are expressed for convex bodies in space, in sections, and in the projection plane.Based on the important concept of total projection, expressions are obtained that correct for truncation and overlap of particles in foils. Approximations to the total projection are developed for lines obscured by surfaces, and for points hidden by surfaces in space. Finally methods for determining size distributions of particles in thin foils are reviewed and recent modifications to the original procedures are discussed.
Stereological methods applied to mineralogy, petrology, mineral deposits and ceramics
Authors: Amstutz G. C. , Giger H. 
Published: August 2011

SUMMARYFirstly, the present development towards a quantitative stereometric (or stereofabric) analysis of mineral aggregates (rocks, ores, concentrates, snow, slags, ceramic materials, cements, etc.) is put into a historic framework. Secondly, the details of the methods and the difficulties still existing are outlined. Finally, a summary is given of the mathematical approaches (with a tabulation of basic formulae), together with some typical examples.
Stereological methods in the analysis of neuronal parameters in the central nervous system*
Authors: Haug Herbert 
Published: August 2011

SUMMARYThe structure of the central nervous system (CNS) is briefly explained. It is compared with the electronic computer and the differences between the two are stated. The methods of measuring this structure and its function are reported.The surface of the cortex as well as the volume of different grey and white matters making up the brain can macroscopically be evaluated on serial slices with the aid of stereological procedures. There is an exponential correlation between volume of the cortex and volume of brain and body in mammals (Fig. 3).The density of neurons and the lengths of their processes can be examined by light microscopy. An improved procedure of counting neurons in the cortex is described. With regard to mammals it is interesting that the densities of neurons in larger brains are lower than in smaller ones. The correlation is negatively exponential. Man and primates have a higher density of cells than the rest of the mammals; their neurons, however, are small. This corresponds to a specialization that can be considered to represent a miniaturization of the neurons (Fig. 4). The topological analysis of dendritic trees is mentioned. The lengths, surfaces and volumes of processes of cells and the amount of synapses can be measured on electron micrographs. The principles and problems of stereology are described by an example of how to measure the myelinated fibres. Some results of the development of these fibres from birth on are reported upon (Fig. 6). In conclusion, some data of the probable dimensions of the human brain are given.
A stereological method for estimating volume and surface of sarcoplasmic reticulum
Authors: Weibel Ewald R. 
Published: August 2011

SUMMARYThe stereological analysis of volume and surface of sarcoplasmic reticulum tubules in muscle cells meets with particular problems because these structures are (a) highly oriented in the longitudinal direction of the muscle cells, (b) lined up in parallel, (c) periodically arranged in relation to sarcomeres and (d) internally symmetrical in analogy to sarcomere symmetry. On the whole this system may be characterized as a parallel linear array of units with translational‐reflexive symmetry. On the basis of a simple model it is demonstrated that the problems of sampling and stereological measurement can be overcome if a combination of oblique and transverse sections are used. The procedure can be simplified to operate exclusively with oblique sections only slightly inclined to the transverse plane if a small systematic error can be accepted.