bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microspectrophotometric studies of Romanowsky stained blood cells
Authors: Marshall Paul N. , Galbraith William , Navarro Erlinda F. , Bacus James W. 
Published: August 2011

SUMMARYThis paper describes a comparison of the performance of two standardized Romanowsky blood stains, namely those of Marshall et al. and Wittekind et al., both containing azure B and eosin alone. Stain performance is assessed objectively by the use of three complementary techniques, all based on the visible absorbance spectra of stained cellular substrates. The first of these techniques is a simple comparison of the shapes and heights of the absorbance spectra. The second technique uses the CIE Colorimetric System, and thus permits the quantitation of colour in a manner that agrees with human observation. CIE co‐ordinates (chromaticity points, luminance) are calculated directly from absorbance spectra. The third technique is that of spectral subtraction, which yields a set of factors which describe the quantities of component dyes which are bound by the object. This technique, unlike the other two, requires a priori knowledge of the dyes used in the stains, and their spectra when bound to cellular substrates.Although the differences between the two methods are subtle, and hard for the subjective observer to define, the objective methods described here do show statistically significant differences. Wittekind's stain produces less intense staining, except for lymphocyte and monocyte cytoplasms. To the human eye, the differential coloration of these two substrates is more pronounced, but the difference between all nuclei and cytoplasms is less marked. The major difference in the uptake of dye components is in the small quantities of eosin dimer that are bound in this technique.
Measuring error and sampling variation in stereology: comparison of the efficiency of various methods for planar image analysis
Authors: Mathieu Odile , Cruz‐Orive L. M. , Hoppeler H. , Weibel E. R. 
Published: August 2011

SUMMARYAn evaluation is made of the relative efficiency (precision of the final estimate per unit time of measurement on a given set of sections) of different methods for planar analysis aimed at estimating aggregate, overall stereological parameters (such as Vv, Sv). The methods tested are point‐counting with different densities of test points (4 ≤ PT ≤ 900 per picture), semiautomatic computer image analysis with MOP and automatic image analysis with Quantimet, for obtaining Vv and Sv estimates. One biological sample as well as three synthetic model structures with known coefficients of variation between sections are used. The standard error of an estimate is mainly determined by the coefficient of variation between sampling units (= sections in the present paper) so that measuring each sample unit with a very high precision is not necessary. Automatic image analysis and point‐counting with a 100‐point grid were the most efficient methods for reducing the relative standard errors of the Vv and Sv estimates to equivalent levels in the synthetic models. Using a 64‐point grid was as precise, and about 11 times faster than using a tracing device for obtaining the estimate of Vv in the biological sample.
Prediction of permeability of non‐woven geotextiles from morphometry analysis
Authors: Masounave J. , Rollin A. L. , Denis R. 
Published: August 2011

SUMMARYThe permeability coefficient of non‐woven geotextiles used for soil stabilization, erosion control and earth reinforcement is predicted from a proposed analytical method. A mathematical model is used to depict both fabric's void and soil particles histograms and related them to forecast eventual clogging level. Experimental data indicated a relationship between water permeability and fibre density of a fabric. Lastly a proposed method is presented for the prediction of the filtration performance of multi‐layer or composite fabrics.
Experiments on the characterization of metamorphic textures from a micrograph of an amphibolite
Authors: Fabbri Andrea G. , Masounave Jaques 
Published: August 2011

SUMMARYPicture processing using generalized instrumentation with specially developed software, and image analysis by means of a Quantimet 720 image analyser with a linear correlator, were employed in the study of rock textures. The boundaries of all individual grains from a portion of a thin section of a rock were distinguished and hand‐drafted for digitization and analysis. From the grey level image of boundaries of the profiles of the grains, obtained by hexagonal scanning of line drawings, binary images were produced for each phase and used for textural measurements. Ink drawings extracted from the boundary pattern were also used for the image analyser experiments.In picture processing experiments, programmed structuring elements of different shapes and two‐dimensional autocorrelation functions were used to characterize morphology and spatial distribution of the different phases. Transformations of binary images were programmed at the bit level to reduce storage requirements and computing time. In Quantimet 720 experiments, linear erosion and histogram of sizes were used for computing the mean dimensions of the grains. Periodical arrangements were studied by means of the covariance function.This contribution uses simple texture measures derived from mathematical morphology and picture processing methods, in order to assess the feasibility of two different technical approaches in the analysis of the same material. The extraction of image information from the material analysed, which was not attempted before, is cumbersome and technically complex. This difficulty is partly responsible of why little is known on the quantitative characterization of metamorphic textures from thin sections.
Cryofixation of monolayer cell cultures for freeze‐fracturing without chemical pre‐treatments
Authors: Pscheid P. , Schudt C. , Plattner H. 
Published: August 2011

SUMMARYA cryofixation method is presented which gives excellent ultrastructural preservation of monolayer cell cultures without any chemical pretreatments. Rat hepatocytes in primary culture were used in this study. The equipment needed is inexpensive and easy to manufacture. Cells are grown on a usual tissue culture support material (Thermanox plastic sheets). For cryofixation, samples are prepared essentially by a combined sandwich‐cryogen‐jet technique. 3 mm large discs are punched out and sandwiched with Cu‐ or Au‐object holders of little mass; a 15 μm spacer is put in between. The viability of the cells is not impaired by the manipulations before freezing. The sandwich sample is quickly frozen by shooting a propane jet from a simple pressure chamber on to the metal object holder. The relevant parameters were optimized by parallel freeze‐fracture analyses of 5% glycerol as a model system and by thermocouple measurements. Sandwich samples are then mounted in an appropriate double replication specimen table for further analysis by freeze‐fracturing. It is possible to obtain a certain selectivity of the fracture plane with regard to apical, lateral or basal aspects of the cell layer. Alternatively, disc samples can be processed by chemical fixation methods (including freeze substitution to determine the freeze‐fracture plane), since the support material Thermanox is insensitive to organic solvents and easy to cut. In each case the cells remain attached to their substratum throughout the whole procedure. Thus, the ultrastructural data can be directly correlated with parallel functional analyses obtained from the same cell cultures.
Sodium localization in Suaeda maritima leaf cells using zinc uranyl acetate precipitation
Authors: Harvey Diana M. R. , Kent B. 
Published: August 2011

SUMMARYThe use of zinc uranyl acetate as a sodium precipitant was investigated during conventional fixation and freeze‐substitution preparations; it was superior to antimonate reagents insofar as it only precipitated Na+ and K+ (Ca2+ and Mg2+ were not detected) and could be used in conjunction with freeze‐substitution in acetone.
The use of a simple method to avoid cell shrinkage during SEM preparation
Authors: Wollweber Leo , Stracke Roland , Gothe Uwe 
Published: August 2011

SUMMARYIn the course of preparing specimens for scanning electron microscopy, both glutaraldehyde and OsO4‐fixed cells exhibit a considerable shrinkage with a reduction of the mean cellular diameter of about 45% after critical point drying. However, if cells are successively treated with glutaraldehyde, OsO4, tannic acid and uranyl acetate solutions, cellular shrinkage of only 5% is observed.
Spatially filtered images of B. subtilisα‐amylase crystals
Authors: Shelley Kirk , McPherson Alexander 
Published: August 2011

SUMMARYMicrocrystals of B. subtilis α‐amylase have been negatively stained and examined by electron microscopy. The micrographs were then subjected to spatial filtering and averaging using a Fourier transform procedure programmed for a mini computer. From these ‘enhanced’ images refined crystallographic parameters were obtained and a model for the packing of the asymmetric units within the crystal was derived. In addition, these parameters obtained from electron microscopy are compared with those derived from limited X‐ray diffraction data on macrocrystals of the same form.
Checking of linearity of the photoelectric system of a microscope photometer
Authors: Piller Horst 
Published: August 2011

SUMMARYFor accurate photometric measurements linearity between the measured property of the object, e.g. transmittance, reflectance, fluorescence intensity, and the measuring signal plays an important role. Although modern photoelectric equipment is designed to provide practically perfect linearity there may be factors by which linearity is disturbed, e.g. ageing, heating, improper operation of equipment, defects in electric circuits, etc. The three‐polar method described in this paper involves the most convenient and objective testing of linearity by the operator.
The suitability of various adhesives as mounting media for scanning electron microscopy: I. Epoxies, sprays and tapes
Authors: Witcomb M. J. 
Published: August 2011

SUMMARYFifty‐six relatively commonly used epoxies, sprays and tapes have been tested with respect to properties that are, or may be, important if they were to be used as scanning electron microscopy sample mounting adhesives. Recommendations are made as to the most appropriate adhesive for each type of mounting media.
Recording of chromosome banding with the Vickers M85/M86 scanning microdensitometer
Authors: Robinson K. , Hartmann‐Goldstein I. J. , Goldstein D. J. 
Published: August 2011

SUMMARYAn electronic interface is described which permits the Vickers M85/M86 microdensitometer to be used with a chart recorder to plot linear distance along a chromosome against (1) the absorbance, (2) the product of the chromosome width and the mean absorbance transverse to the long axis of the chromosome, or (3) the integrated absorbance accumulating during a two‐dimensional scan of the specimen.
Resolution in light microscope autoradiography using a carbon‐14 labelled line source
Authors: Vanroelen Ch. , Harrisson F. , Andries L. , Vakaet L. 
Published: August 2011

SUMMARYLight microscope autoradiographs were prepared from a 14C line source. Two factors that affect resolution were studied: emulsion thickness and section thickness. The distribution around the line source was determined using the half‐distance (HD) value to quantify the resolution. An increase in HD value was observed with thicker sections or emulsion layers. The shape of the curve reflecting the grain density distributions around these line sources was very similar. After normalization in HD and relative grain density units, an average distribution was calculated and compared with the shape of normalized density distributions obtained from electron microscope autoradiographs. Other than a discrepancy near the source, an acceptable correlation was observed.
A new approach to the study of the E. coli nucleoid
Authors: Haggis G. H. , Bond E. F. 
Published: August 2011

SUMMARYE. coli were examined by the freeze‐fracture thaw‐fix technique, embedded in thin fibrin gels. After glutaraldehyde fixation the bacterial nucleoid was found spread out over the surrounding fibrin. Addition of calcium and uranyl acetate to the fixative preserved the nucleoid in compact form. The spread nucleoid was then examined against a smooth mica background after freeze‐thaw and osmotic lysis. These spreads were critical‐point dried, rotary shadowed with platinum–carbon and viewed as stereo‐pair micrographs. Structures seen are tentatively interpreted as clusters of polyribosomes, extended DNA, and supercoiled DNA complexed with proteins or polyamines. After osmotic lysis, glutaraldehyde alone preserves the nucleoid in compact form. Only where strands are broken, in freeze‐fracture or freeze‐thaw lysis, must uranyl acetate be added to the fixative to preserve a compact structure.
The application of a normalized correlation function in image analysis
Authors: Vollath D. 
Published: August 2011

SUMMARYThis paper describes the use of normalized correlation functions, such as auto‐ and cross‐correlation functions for the analysis of images. The normalization is introduced to avoid problems of interpretation of the resulting correlation functions caused by the finite dimension of the image used for calculation.Due to a reduction of noise in the correlation function it is possible to detect periodic structures, which are hidden by noise in the original image. Besides the normalization of the correlation functions, a modification of the correlation function by periodic continuation of the image is proposed. This leads in all cases where the structure allows this to a further drastic reduction of noise.Besides the two‐dimensional correlation functions one‐dimensional correlation functions are proposed. It is shown that there are cases where it is difficult to find an adequate interpretation of these one‐dimensional functions.
The use of various buffers in the preparation of human lymphocytes for SEM observation
Authors: Abugaber Antoine A. , Lalague Elisabeth D. , Roy Adolphe , Champagne Marc R. , Cousineau Gilles H. 
Published: August 2011

SUMMARYA study is presented of various buffers utilized in the preparation of human lymphocytes for scanning electron microscopy. Of nineteen different buffers tested, Hanks' balanced salt solution +0·04 mol sucrose appeared most adequate for satisfactory preservation of lymphocyte surface architecture.
Freeze‐drying shrinkage of glutaraldehyde fixed liver
Authors: Boyde Alan , Franc Frantisek 
Published: August 2011

SUMMARYDimensional changes were recorded during the freeze drying (FD) of 1 mm cubes of glutaraldehyde (GA) fixed adult mouse liver. The areas of the front faces of these blocks was measured using a Quantimet 720 image analysing computer system. Interpolating the first straight line portion of the graphs of size versus time backwards to the origin allowed the determination of the original size even if the specimen was covered with some surface‐water ice at the beginning of the experiment.GA fixed mouse liver shrinks 7·3% linearly during freeze drying. This gross shrinkage is not increased if the cold stage temperature is raised to ∼263 K from ∼223 K, but the rate of drying as monitored by the rate of shrinkage is greatly increased. If morphological specimens are to be prepared for scanning electron microscopy (SEM), freeze drying can be completed rapidly after an initial period at ∼223 K, since ice recrystallization leading to increased ice crystal artefact will occur in the deep layers which will not be visible in the SEM.Shrinkage of single cells followed during freeze drying in the SEM showed similar gross dimensional changes of about 7·5% linear shrinkage to occur at and below 198 K.
The design of terrestrial and aquatic micro‐environmental chambers for use in low powered video, cine and photomicrography
Authors: Lawrence Michael J. 
Published: August 2011

SUMMARYThe observation, recording and control of active biological specimens is time consuming and not easily achieved in low powered microscopy. To overcome this, perspex micro‐environmental chambers have been designed to enable the control of temperature, air and water flow, illumination and image format to suit individual species and specimens. When the chambers are in use, they are ‘closed’ systems and can be maintained for long periods; up to several days if required.Two separate systems have been developed (aquatic and terrestrial) and both allow the use of integrated illuminated systems. The chambers are made from perspex and the viewing area, the ‘windows’, are made from high quality optical glass.These chambers have been designed to match television format (3:4) and retain the specimen and ensure it remains in the field of view during a video, cine or photomicrographic recording session. The chambers can be used in vertical or horizontal observation systems and are attached to the microscope focusing substage. It also allows the use of incident and transmitted illumination systems including bright field, with or without polarized light observations, and dark field. The assembly of the chambers appears complex but is easily achieved.
The construction of invariant random paths through three‐dimensional specimens
Authors: Coleman Rodney 
Published: August 2011

SUMMARYA quick way of constructing invariant random (IR) paths (sometimes called IUR or μ‐random) through three‐dimensional specimens is described. It uses the result that the secant joining two points chosen uniformly and independently on the surface of a sphere is IR.An application of this result to the stereology of multiple phase spheres is briefly introduced.
High voltage electron microscopy of cell nucleus fractions: feasibility studies
Authors: Bourgeois C. A. , Zalta J. , Lacaze J. C. , Zanchi G. , Kihn Y. , Bouteille M. , Jouffrey B. , Zalta J. P. 
Published: August 2011

SUMMARYCell nucleus fractions were analysed in high voltage electron microscopes equipped with a hydration chamber and an energy filter, and the different filtering modes were tested. The best results were obtained when the energy filter was used as an analyser of atomic tracers specifically combined with RNA. Although the resolution thus obtained was relatively poor, the prospects of being able to observe hydrated organelles are encouraging.
An X‐ray microanalytical examination of precipitation methods for the ultrastructural localization of potassium in plant tissue: I. Cobaltinitrite
Authors: van Steveninck Margaret E. , van Steveninck R. F. M. , Mittelheuser Cathryn J. 
Published: August 2011

SUMMARYIn vitro and in vivo studies were carried out to assess the feasibility of adapting the cobaltinitrite method for the ultrastructural localization of K+ in plant cells. The relatively low mobility of the cobaltinitrite ion and the solubility of the precipitation product resulted in the formation of only a few large deposits in each cell. The addition of Ag+ at the time of precipitation was found to increase the number of small deposits retained in sections. However, cobaltinitrite reagents frequently caused plasmolysis and poor cytoplasmic preservation. Precipitation during freeze‐substitution was also attempted. It was concluded that precipitation of K+ using cobaltinitrite has only limited use in low magnification electron microscopy in conjunction with light microscopy.
Comparative mass measurement of biological macromolecules by scanning transmission electron microscopy
Authors: Freeman R. , Leonard K. R. 
Published: August 2011

SUMMARYA method is described for measuring the mass/length or mass of molecular assemblies by comparative electron scattering in the STEM. Standard particles whose mass is well established (e.g. TMV or fd bacteriophage) are deposited on the electron microscope grid together with the sample to be measured. Images containing at least one sample and standard and with a clean, contamination‐free background are chosen and stored on computer disc and then directly integrated. Use of a comparative technique does not require accurate determination of scattering parameters or instrumental geometry and requires only that the limits of linearity be established.The results of the mass/length measurements on phage pf 1, pili, muscle thick filaments and actin are in good agreement with existing molecular weight data and generally have a standard deviation of about 10%. The results for the total mass measurement of the multisubunit enzymes glutamate dehydrogenase and glutamine synthetase are also close to the literature values for their molecular weights. The results for the spherical, Semliki forest and tomato bushy stunt viruses are lower than expected, possibly reflecting some dissociation during preparation.
Comparative light microscopy, scanning electron microscopy and transmission electron microscopy of selected organic walled microfossils
Authors: Peat C. J. 
Published: August 2011

SUMMARYTwo simple techniques are described and illustrated. The first is for the study of one specimen by both light microscopy (LM) and scanning electron microscopy (SEM). The second is for the study of one selected specimen by LM, SEM and in ultrathin section by transmission electron microscopy (TEM). Although these techniques were developed for the comparative study of Precambrian organic walled microfossils (OWMs), they could be used for a wide range of other specimens.
Photoelectron microscopy of cell surface topography
Authors: Nadakavukaren Karen K. , Rempfer Gertrude F. , Griffith O. Hayes 
Published: August 2011

SUMMARYPhotoelectron micrographs of gold‐palladium coated mouse 3T3 cells and chick embryo fibroblasts are presented. Since the gold‐palladium suppresses differences in work function, the cell morphology seen in these micrographs is due to relief contrast. The heights of comparable cells were measured from the parallax present in transmission electron micrograph stereo‐pairs of cell surface replicas. The origin of relief contrast and the effect of cell surface relief on the working depth of field in photoelectron images of cells are discussed. The micrographs demonstrate that photoelectron microscopy is very sensitive to fine details of cell surface topography, and that the working depth of field is not a limiting factor in the imaging of well‐spread tissue culture cells.
A rapid method for identification of S‐phase cells in transmission electron microscopy of monolayer cultures
Authors: Alvey Peter L. 
Published: August 2011

SUMMARYA rapid technique has been developed for identifying cells in S‐phase in transmission electron microscopy of monolayer cultures. Autoradiography is performed on the embedded monolayer which is then re‐embedded. The cells and the adjacent layer of developed emulsion are sectioned together, and when subsequently viewed in the electron microscope the cells in S‐phase appear with a zone of silver grains in the emulsion which is opposite their nuclei. They are thus readily identified and can be selected for detailed study. The advantages of this technique over conventional TEM autoradiography are the very much shorter exposure times and a reduced workload when preparing serial sections.
Ion beam sputtering: an improved method of metal coating SEM samples and shadowing CTEM samples
Authors: Clay Christopher S. , Peace Geoffrey W. 
Published: August 2011

SUMMARYAn apparatus to ion beam sputter‐coat SEM samples has recently become available. The equipment uses a small saddle‐field ion source to sputter deposit metals on to samples. This eliminates the surface artefacts seen at high magnifications on samples coated by diode sputtering. Ion beam sputtering has also been used to shadow samples for CTEM and has been found to result in a grain size of 1.2 nm.This technique isolates the specimens from the high‐energy plasma and thus little or no heating of the sample occurs. The removal of the SEM samples from the high‐energy plasma and the use of diffusion pump vacuum conditions to prevent contamination are suggested as reasons for the improved coating quality over diode sputtering.