bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantitative measurement of human articular surface topography in vitro by profile recorder and stereo‐microscopy techniques
Authors: Clarke Ian C. 
Published: August 2011

SUMMARYThe degree of irregularity presented by the 20–40 μm diameter depressions in adult human articular surfaces was measured in vitro, using the scanning electron microscope (SEM), replication, stereo‐microscopy and profile recording techniques.Using stereo‐microscopy, the measured articular surface depressions varied from 0.9 to 15 μm in depth and the corresponding humps on the replicas varied from 0.3 to 8.9 μm in height. The heights of the replicated contours measured by the profile recording device varied from 0.2 to 5 μm. It was emphasized that, while these values give some indication as to the possible degree of surface irregularity in vivo, the actual contours in a living, load‐bearing joint may be quite different.
The Polanret variable densiphase microscope
Authors: Richards Oscar W. 
Published: August 2011

SUMMARYContinuously variable contrast, phase microscopy is obtained with the Polanret microscope by adjusting one control for phase retardation and another for the two kinds each of bright and dark contrast. The B + type dark contrast is available in a commercial instrument. The Polanret unit fits on recent, AO‐Spencer microscopes and accepts standard trinocular to monocular bodies and cameras. Densiphase detail (absorption, optical path and combinations of them) can be made visible optimally and selectively with the complete range and four kinds of contrast provided within the Polanret system. Illustrations show the need for and advantage of variable contrast, over fixed‐phase objectives. Applications include: unstained cells and tissues, biopsy tissues, transparent industrial materials, isotropic minerals, moderately absorbing materials, pigmented tissues, thin sections (nm range and thicker), and refractive index measurement of transparent and opaque materials.
The determination of the geometry and nature of small Frank loops using the weak‐beam method
Authors: Jenkins M. L. , Cockayne D. J. H. , Whelan M. J. 
Published: August 2011

SUMMARYTheoretical and experimental investigations have been carried out to determine under which conditions weak‐beam images can give useful information on the geometry, size and nature of small Frank loops. Suitable experimental conditions for obtaining such information were deduced from computed weak‐beam images of Frank loops under various selected loop and foil orientations and diffraction vectors. Experiments to check these deductions were performed in silicon damaged by irradiation with phosphorus ions. It was found that the geometry and size of loops of diameter 8 nm (80 Å) viewed normal to their habit plane was well defined by weak‐beam images taken in {220} reflections lying in the loop plane for which g.b = 0 and g.b × u ≠ 0. By imaging in reflections with g vectors not in the loop plane the enclosed stacking faults were imaged (thus confirming the loops to be Frank loops) and the sense of the Burgers vector (i.e. the loop nature) was determined.
Observations of lattice defects using the weak‐beam technique
Authors: Guyot P. 
Published: August 2011

SUMMARYThe advantages of the weak‐beam technique of electron microscopy for the study of small defects and dislocations are illustrated by micrographs taken of small loops in aluminium and Al–Ag alloys, GP zones and θ″ precipitates in Al + 4% Cu, and dislocation networks in Cu + 20% Zn. An estimate of 19·5 mJ m−2 (erg cm∼2) is made for the stacking‐fault energy of Cu–20% Zn from the size of extended nodes and the width of the dissociated dislocations imaged under weak‐beam conditions.
High resolution dark‐field electron microscopy
Authors: Dubochet Jacques 
Published: August 2011

SUMMARYIn the last few years some promising images of biological specimens have been obtained using the high contrast and resolution of dark‐field electron microscopy. However, important problems of image interpretation and difficulties in specimen preparation limit at the present time, the usefulness of this mode of image formation. The destruction of the sample by the electron beam, is of utmost importance. Some possibilities of partly overcoming it are discussed.
A low cost, one‐piece nitrogen burst processing rack for 3¼× 4 inches and 4×5 inches TEM and SEM negatives
Authors: Thurston E. Laurence , Scott James R. , Schroeter Gilbert L. 
Published: August 2011

SUMMARYA processing rack designed with a built‐in nitrogen burst plenum to accommodate 3¼ × 4 in. and 4 × 5 in. negative can be inexpensively constructed from plexiglass.
A new type of storage container for freeze‐etch specimens
Authors: Krah Stephanie , Staehelin L. Andrew , Nettesheim Eugene 
Published: August 2011

SUMMARYA new storage container for freeze‐etch specimens is described which (1) dramatically reduces the loss of liquid nitrogen from the storage dewar, (2) which always sits on the bottom of the dewar and can be quickly identified and retrieved therefrom, (3) which cannot open accidentally during long term storage and (4) which can withstand continual exposure to temperature extremes. Using such containers over 300 different kinds of specimens can be readily stored in a 30 1 liquid nitrogen dewar.
High resolution microanalysis of aluminium solid solution alloys using combined electron microscopy and energy analysis
Authors: Edigton J. W. , Hibbert G. 
Published: August 2011

SUMMARYThe technique of combined electron microscopy and energy analysis is described, together with the main energy loss process that is used to analyse composition. It is shown that the spatial resolution of the technique is ∼ 14 nm which is ten times better than any other technique available at present. The composition resolution in aluminium alloys is < 1 at.%, the exact value depends upon which alloy system is used.Applications of the technique to the measurement of fine scale concentration gradients are described for Al‐Cu, Al‐Mg and Al‐Zn‐Mg alloys.
Examination of cell suspensions prepared by cryobiological techniques*
Authors: Werner Gerhard , Neumann Klaus , Morgenstern Eberhard 
Published: August 2011

SUMMARYUltrathin frozen sections have been obtained from single cells both in the fixed and native state. For fixed material a rapid method is described which yields excellent structural preservation. The preparation is based on brief treatment with glutaraldehyde, polyvinylpyrrolidone and ‘encapsulation’ in gelatin. Ultra‐thin frozen sections prepared after this technique seem to be especially suitable for cytochemical work. Unfixed testis has been also cut with a dry knife. The contrast in this completely untreated section is sufficient to discern the different parts of spermatozoa.
A system for simultaneous stimulation and film‐marking during cinemicrography
Authors: Klipple Kenneth , Bagby Roland M. 
Published: August 2011

SUMMARYIn this report a stimulation slide is described which is simple to manufacture and which may be used with all microscope objectives, including oil immersion types. The event‐marking system described herein gives a distinct spot visible during projection, and the apparatus is highly dependable despite the inexpensive components used.
Modern techniques in reflectance measurements
Authors: Piller Horst 
Published: August 2011

SummaryIn the field of quantitative investigation of microscopic images reflectance measurements with the aid of photoelectric equipment play an important role. Reflectances can be used for the identification of various components in a polished specimen, for chemical analysis and for the determination of the refractive index of a specimen as well as for a determination of the various absorption parameters of reflecting solid material.The parameters involved are: reflectances at given wavelengths, spectral reflectance curves in the visible, UV‐, and near IR‐spectral range, reflectances of optically anisotropic surfaces at varying orientations of the vibration plane of linearly polarized light, reflectances in air and in an immersion liquid (mainly in standard immersion oil). From spectral curves, quantitative expressions of colour can be derived. Due to improvements in reflectance standard materials and technical design of apparatus the measurements and calculations can be carried out very conveniently, quickly and precisely.
FIM analysis of dislocation core structure
Authors: Brandon D. G. , Melmed A. J. 
Published: August 2011

SummaryA direct colour superposition technique has been used to study two dislocations in W, using He field‐ion imaging at 77°K. Limitations due to instrumentation and field‐ion microscopy are discussed. A single spiral and a double spiral on (112) W were each dissected, by field evaporation, through three successive atom layers, and apparent core shapes and dimensions were determined. The shapes were irregular with diameters of at most 0.5–2 nm for the single spiral and 0.5–1.7 nm for the double spiral. Observed displacements in the positions of the core regions may be associated with dislocation movement induced by the high electric field needed for the observations.
Ultraviolet microscopy at wavelengths below 240 nm
Authors: Wood J. R. , Goring D. A. I. 
Published: August 2011

SummaryModification of the techniques used for ultraviolet microscopy have allowed extension of the usable wavelength range down to about 220 nm. The 150 W xenon lamp in a Leitz ultraviolet microscope was replaced with a 1000 W xenon‐mercury lamp. A special low gelatin content film was employed and a new epoxy embedding medium of low UV absorbance was formulated.
Classification of crystalline interfaces by means of the O‐lattice method
Authors: Bollmann W. 
Published: August 2011

SUMMARYThe different kinds of crystalline interfaces can be classified by means of the O‐lattice method. Two groups of parameters have to be known for the description of an interface. The first group concerns the structures and the relative orientation of the adjoining crystals and the second group deals with the position and orientation of the interface. The O‐lattice method allows one to deal with the two groups of parameters independently. This method gives a description of the interface in terms of dislocations, and hence of the possible relaxation in the boundary. Different kinds of interface will be discussed and illustrated by electron micrographs.
Observations of dislocations in [011] symmetrical tilt boundaries near Σ9 C.S.L. in aluminium
Authors: Silcock J. M. , Kegg G. R. , Horton C. A. P. 
Published: August 2011

SUMMARYBicrystals with [011] symmetrical tilt boundaries rotated 36° have been examined by transmission electron microscopy. The boundary which was near a (41) plane showed networks of structural grain boundary dislocations. Possible vectors were derived from Bollmanns coincident site lattice theory for the nearest C.S.L., i.e. Σ9. The networks have been examined in a number of reflections and are considered to be composed of dislocations with b2 (i.e. 1/9 [12]) and b3 (1/6 [121] or 1/18 [127]) vectors. Four b3 vectors can change from one to the other by interactions with other structural dislocations. Evidence of iron additions reducing the mobility of dislocations is presented, and evidence of lattice dislocation dissociations are discussed. The mobility of dislocations in this Σ9 C.S.L. boundary is compared with a Σ27 coincidence lattice.
Grain boundary dislocations and the mechanism of sliding in symmetrical [011] tilt Al bicrystals
Authors: Horton C. A. P. , Silcock J. M. 
Published: August 2011

SUMMARYObservations of grain boundary dislocations in [011] tilt bicrystals of aluminium after high temperature shear tests have led to a concept for grain boundary sliding that involves extrinsic dislocations moving through an array of structural dislocations. Each extrinsic dislocation consists of a group of structural dislocations with closer than normal network spacing caused by the presence of an extra dislocation with the same Burgers vector. The extrinsic dislocation exhibits a long range strain field and can move individually through the array of structural dislocations. The movement involves displacements in the structural network analogous to atom displacements during crystal slip. The width of the extrinsic dislocation on the grain boundary plane is dependent on the degree of accommodation of the extra dislocation by the structural array and this appears to increase with increasing density of structural dislocations.
Exposure level and image quality in electron micrographs
Authors: Farnell G. C. , Flint R. B. 
Published: August 2011

SUMMARYSingle electrons of the energies used in transmission electron micrography can render developable one or more emulsion grains. From this fact the following deductions can be made.

Photographic contrast in an electron micrograph is a function of the mean density only.
The signal/noise ratio in an electron micrograph improves with increasing exposure, irrespective of the means adopted to enable an increased exposure to be used.
If the exposure of the specimen is limited to some maximum then the visibility of noise‐limited detail in prints representing a given total magnification is independent of the negative material used in the microscope.

Experimental tests based largely on electron micrographs are presented which provide good support for these deductions. It is generally concluded that the behaviour patterns examined in this work should always be considered when limitations are being encountered in the image quality of electron micrographs.
A method for adapting the Leybold device for obtaining complementary replicas to the Balzers unit
Authors: Sleytr Uwe B. 
Published: August 2011

SUMMARYA simple method is described for adapting the Leybold complementary replica device, which is equally useful for the examination of suspensions and tissue fragments, to the Balzers freeze‐etching unit. The only change necessary for using the device in the Balzers unit, is to unscrew the Balzers specimen table from the cold stage and replace it with an adapter. If prolonged etching is required, a contamination shield is mounted on the microtome arm in place of the razor blade.
Positive displacement holder for critical point drying of small particle materials*
Authors: Baker F. L. , Princen L. H. 
Published: August 2011

SUMMARYA specimen holder has been designed specifically to contain small particulate matter, such as microorganisms, fibres or powders, during the fluid exchange cycle and final evaporation step of the critical point drying process. The mode of fluid exchange is positive displacement rather than diffusion. The holder can accommodate up to ten different samples without loss of material or cross‐contamination during the dehydration process. The samples are separated by silver membrane filters, and fluid exchange is accomplished in minimal time by only slight positive pressure. Experiments with soluble dyes have shown that any fluid can be displaced completely with another in less than 2 min, whereas diffusion requires more than 30 min. The holder and individual capsules have been tested with different materials and a standard water/ethyl alcohol/amyl acetate/carbon dioxide fluid sequence. This paper describes the design, production, and testing of the holder and capsules, and presents selected examples of results.
The myofibrillar M‐band in the cryo‐section—analysis of section thickness
Authors: Thornell Lars‐Eric , Sjöström Michael 
Published: August 2011

SUMMARYInformation regarding the formation and the thickness of cryo‐sections is of importance for an adequate interpretation of cryo‐sectioned biological material. In this study we have taken advantage of the regular arrangement of filaments in myofibrils in an analysis of these matters. It is concluded that the sections are formed partly by fracturing in a way similar to that visualized in replicas made by the freeze‐fracturing and ‐etching procedure.
The preparation, examination and analysis of frozen hydrated tissue sections by scanning transmission electron microscopy and X‐ray microanalysis
Authors: Saubermann Albert J. , Echlin Patrick 
Published: August 2011

SUMMARYA method is reported for preparing, examining and analysing frozen hydrated tissue sections using transmission electron microscopy and X‐ray microanalysis. Use of this method permits localization and measurement of water soluble or diffusible elements within the hydrated cell matrix. Since any change in total fresh weight of the specimen will affect the concentration of all components, great care has been taken to demonstrate that the mass neither increases nor decreases and to ensure that the tissue remains frozen‐hydrated. Criteria for assessing whether or not the tissue remains frozen‐hydrated are reported.After quench freezing, 1–2 μm thick sections of mouse liver were cut at 193°K and picked up on a specially designed annular specimen holder covered with an aluminium coated nylon film. Using a transfer device which prevents contamination of the tissue sections while maintaining them at a low temperature (below 143°K), the sections are transferred either to the vacuum evaporator cold stage or the scanning microscope cold stage. The tissue sections may be coated with an aluminium layer to improve electrical and thermal conductivity. The specimens are examined in the scanning transmission imaging mode and analysed using an energy dispersive X‐ray analyser. Concentration of intra‐nuclear and intracytoplasmic K, P, S and Cl are reported for mouse hepatocytes as ratios of the characteristic radiation to the continuum radiation used as a measure of mass. Ratios for all four elements were higher in the nucleus than the cytoplasm. Examples are given of this method as applied to plant and insect tissue.
The use of moiré patterns to determine the source and degree of adistortion in scanning electron microscopes
Authors: Bradley S. A. , Thielen P. N. , Hilliard J. E. 
Published: August 2011

SUMMARYScanning electron microscope images are subject to an appreciable amount of non‐linear distortion which must be allowed for when quantitative analyses are made. A method is described for measuring the distortion by the use of moiré patterns. These greatly magnify any non‐linearities and it is possible to measure distortions as small as 0ṁ1%. In addition, the use of moiré patterns permits a separation of the distortion produced in the cathode‐ray display tube from that occurring in the microscope itself.
Plant‐cell structures in vitrinite chars
Authors: Goodarzi F. , Murchison D. G. 
Published: August 2011

SUMMARYThis paper describes the occurrence of plant‐cell structures retained in particles of the principal coke‐forming constituent (vitrinite) of a coking coal, which has passed through its decomposition point during carbonization using several rates of heating. The benefits of wider application of the study of organic constituents with high optical absorptions under crossed polars in reflected light are emphasized. Relief‐polished surfaces of certain of the vitrinite‐char particles, which appear virtually structureless in plane‐polarized light under oil immersion, when viewed under crossed polars not only possess well‐preserved plant‐cell structures, but also show development of a mosaic structure from a mesophase in situ with virtually no disturbance of even the cell walls. Retention of the original cell structure is almost certainly governed by a reduced reactivity of this vitrinite induced by oxidation of the original plant tissues at the time of their deposition in the coal‐forming swamp.
The use of direct deposition electron microscope autoradiography in studies of protein transport
Authors: Hemmings W. A. , Williams E. W. 
Published: August 2011

SUMMARYThe use of direct deposition autoradiography in studies of the localization of proteins labelled with radio‐iodine or tritium in the epithelia of fetal, suckling, and adult animals is described. Using a single marker in the first place, rabbit IgG and bovine IgG have been seen both in the vacuolar apparatus and also free in the cytoplasm of endodermal cells of the rabbit yolk‐sac splanchnopleur. This has been confirmed in those cells using a combination of bovine IgG marked with tritium and rabbit IgG marked with 125I, presented simultaneously to the cells. Both proteins are present, apparently equally, attached to the brush border and distributed through the cytoplasm, as well as within vacuoles. Selection does not take place before or during entry to the cell, as has been suggested by quantitative results which have been reported elsewhere. It is hoped that the use of two markers together will permit localization of the selective process. In the adult rat gut, both isotopes have been demonstrated entering and within and leaving the ileal cell, confirming quantitative results reported elsewhere.
Hyperactivity and faster replicating property of the two arms of the male X of Drosophila pseudoobscura*
Authors: Mukherjee A. S. , Chatterjee S. N. 
Published: August 2011

SUMMARYThe two arms of the X chromosome of Drosophila pseudoobscura have different phylogenetic origin, the XL being homologous to the X and the XR homologous to the 3L of D. melanogaster. The replicative and transcriptive activities of the two arms have been examined in order to understand how such phylogenetically different components of the X contribute toward the chromosomal basis of dosage compensation. The 3H‐uridine labelled autoradiograms of the polytene chromosomes of larval salivary glands reveal that the intensity of labelling in the XL and XR of the male is not significantly different from that in the two arms of the female, respectively. The number of grains on the two arms plotted against the grain number on an autosome follows a linear regression, and neither slope in the male is significantly different from its counterpart in the female. The 3H‐thymidine autoradiograms show that in all phases of replication, viz. initial, middle and terminal, both arms of the X chromosome in the male are advanced by one step in the cycle. Results, therefore, suggest that both arms of the X of D. pseudoobscura, are hyperactive and faster replicating in the male. Such a situation might arise due to a primary signal coming from autosomally located regulators controlling the super‐operon structure of the X chromosomal genes.
An in situ field‐ion microscope research of radiation damage in tungsten
Authors: Tamaki Shozo 
Published: August 2011

SUMMARYResults of experiments in which tungsten was irradiated in situ in the field‐ion microscope with inert gas ions are described. Tungsten field‐ion specimens were irradiated at 78 K with ions in the 0.5–9 keV energy range. Sputtering and displacement of surface atoms which had occurred during irradiation were observed directly in field‐ion images. Large scale damage such as vacancy clusters were rarely found. From the ion acceleration voltage and the accommodation coefficient, the displacement energy of tungsten surface atoms in the electric field of about 44 MV/mm is estimated as nearly 22 eV. Damage was observed on the shielded side of the tip apex as well as on the ion incident side, and this fact is discussed in comparison with the channelling of ions in tungsten.