bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blue molybdenum oxides: A stain for light and electron microscopy
Authors: Ferrer J. M. , Tato A. , Stockert J. C. 
Published: August 2011

SUMMARYBlue molybdenum oxides (molybdenum blues) have been prepared from aqueous phosphomolybdic acid solutions and applied to thin and semi‐thin sections of glutaraldehyde‐fixed, epoxy‐embedded tissues. A light blue colour and high electron opacity were found in mast cell granules, the secretion content of goblet cells, and cytoplasmic granules in Drosophila salivary glands. The possibility that binding of blue molybdenum oxides to polyhydroxylic components accounts for the staining and contrasting reactions in some cell structures is briefly discussed.
Surface roughness and the use of a peak to background ratio in the X‐ray microanalysis of bio‐organic bulk specimens
Authors: Boekestein A. , Thiel F. , Stols A. L. H. , Bouw E. , Stadhouders A. M. 
Published: August 2011

SUMMARYThe use of a net peak intensity and of a peak to background (P/B)‐ratio of sulphur and chlorine is examined in the X‐ray microanalysis of a 2·4% w/w S bulk standard in Spurr's epoxy resin. In calculating the P/B‐ratio, the background intensity is calculated for the same energy region as for the net peak. Analyses were carried out on the flat top of the standard and on the slope running down from the top on the side not facing the X‐ray detector. The results obtained for the peak to local background ratios from the top and the slope yielded a relatively small mean deviation (11%) while net peak intensities ultimately were reduced to 7% or less of the initial value for the flat top. This indicated that a peak to local background ratio is to be preferred in the quantitative analysis of bulk specimens which have poorly defined local tilt and takeoff angles. A second advantage is the inherent correction for beam current fluctuations.
A simple inexpensive cryogenic storage device for microscopy specimens
Authors: Rigler M. W. , Patton J. S. 
Published: August 2011

SUMMARYCryogenic storage devices for microscopy specimens are costly and may require a particular size or type of dewar. Described here is a simple inexpensive storage container for small specimens (< 5 mm in diameter) which can be constructed in less than 15 min from common laboratory materials. The unit is modular in design, can fit into any thermos type dewar and is reusable.
Accurate method of measuring grain misorientations and analysing grain boundary planes in TEM
Authors: Voice W. E. , Faulkner R. G. 
Published: August 2011

SUMMARYA description of a TEM method for accurately determining the misorientation across grain boundaries, and identification of the grain boundary plane is given. The method is equally applicable to thin or thick foils and possesses the accuracy of Kikuchi line analysis. A computer program is available to process the TEM data to yield directly the grain boundary misorientation parameters. Examples of the application of the method to grain boundary structure determination in a nickel base superalloy, Nimonic 80A, are quoted.
Improved imaging of phase gradients in scanning optical microscopy
Authors: Hamilton D. K. , Sheppard C. J. R. , Wilson T. 
Published: August 2011

SUMMARYPrevious work has used a circular large area split detector for phase gradient imaging; it is shown that substituting an annular split detector offers improvements in frequency response, particularly for weak phase gradients. Transfer functions are calculated and transmission and reflection micrographs demonstrate the different imaging properties. Other forms of detector are also considered, some of these possessing certain advantages.
Variations in fungal spore dimensions in relation to preparatory techniques for light microscopy and scanning electron microscopy
Authors: Beckett A. , Read N. D. , Porter R. 
Published: August 2011

SUMMARYThe volumes of urediospores of Uromyces viciae‐fabae and ascospores of Sordaria humana in the critical point‐dried, freeze‐dried, osmium vapour‐fixed/freeze‐dried, frozen‐hydrated and ‘wet’ states were measured. Dried spores shrank and were significantly smaller than frozenhydrated and ‘wet’ spores. Urediospores exhibited a greater range of dimensional changes in relation to the preparatory treatment than did ascospores. Ascospores, dried in different ways, were not significantly different from each other but were significantly smaller than frozenhydrated ones. Both urediospores and ascospores dehydrate naturally and collapse. On wetting they imbibe water rapidly and swell. Low temperature scanning electron microscopy may be suitable for investigating fungal spores in their ‘natural states' on the leaf surface.
A generalization of atom location by channelling enhanced microanalysis
Authors: Krishnan Kannan M. , Thomas Gareth 
Published: August 2011

SUMMARYThe technique of atom location by channelling enhanced microanalysis (ALCHEMI), has limitations in practical application. A generalization of this technique, with the underlying idea that additional relationships can be generated by performing these experiments at an appropriate number of orientations depending upon the stoichiometry of the original compound has been developed. The precise number of orientations required to solve the distributions in a whole class of related compounds is expressed in terms of the stoichiometry of the original compound along with the alloying additions.
Stereo presentation of Monte Carlo electron trajectory simulations
Authors: Bright David S. , Myklebust Robert L. , Newbury Dale E. 
Published: August 2011

SUMMARYElectron trajectory data from Monte Carlo simulation techniques is three dimensional in nature, and thus is best represented by methods that most preserve the spatial information. Stereo plotting is a method that gives the three‐dimensional illusion effectively while not requiring any special equipment beyond what is required to make standard two‐dimensional plots. Stereo plots of electron trajectories are presented that illustrate the advantages of the spatial illusion in the context of examining in detail some of the interactions of the electron beam with planar bulk meta lic samples.
The comparison by simulation of solutions of Wicksell's corpuscle problem
Authors: Blödner R. , Mühlig P. , Nagel W. 
Published: August 2011

SUMMARYIn this paper six distribution‐free (nonparametric) stereological methods for the solution of Wicksell's corpuscle problem—i.e. the determination of the distribution of diameters of spheres embedded in an opaque specimen from the diameters of their profiles on plane sections—are compared as regards their numerical stability, sensitivity to underlying distributions and certain error criteria. The study is based on the results of simulation studies for several types of distribution (one‐point, normal, exponential, logarithmic normal) of sphere diameters. Recommendations are suggested for the choice of methods, sample size and the optimal number of classes for grouping sample data.
Fracturing of melamine‐embedded cells and tissues: a new technique for studying cell membranes
Authors: Westphal Christel , Frösch Dieter 
Published: August 2011

SUMMARYA new technique is presented for studying cell membranes by scanning electron microscopy. It is based on the observation that cells and tissues, embedded in a water‐compatible melamine resin, are as hard as glass and consequently can be fractured with ease. Fracture faces so exposed are either sputter‐coated for studying the surface topography or re‐embedded for thin‐sectioning, or both.Scanning electron microscopy shows that the fracture faces of a variety of tissues reveal cell membranes and associated structures with remarkable detail. Re‐embedding and thin‐sectioning of fractured frog retina, mycoplasma and red blood cells indicate that membranes become divided into their exo‐ and protoplasmic leaflets during fracturing. In this respect, the results reported here must be compared with conventional freeze‐fracture techniques.
Interferometric determination of the optical properties of fibres with irregular transverse sections (Ramie)
Authors: Hamza A. A. , Sokkar T. Z. N. , Shahin M. M. 
Published: August 2011

SUMMARYThe thickness of fibres and their irregularity were determined from the forward scattering of a He‐Ne laser beam. Two methods have been used for the measurement of refractive indices and birefringence of Ramie fibres. The first of these methods is the application of multiple‐beam Fizeau fringes in transmission and at reflection. The second is the use of the double refracting interference microscope designed and developed by Pluta. In each method, refractive index values have been determined using two different analyses of the interference pattern. To overcome the difficulty of the irregular transverse section of Ramie fibres, the area enclosed under the fringe shift is considered as representing the path difference integrated across the fibre.
A technique for comparative light and scanning electron microscopy of the same deparaffinized microtomed section*
Authors: Pattee H. E. , Mohapatra S. C. , Agnello E. K. 
Published: August 2011

SUMMARYEvaluation of various types of clear plastic support material for light and scanning electron microscopy of the same section was conducted. GelBond was found to be the most satisfactory among seven different types of plastic materials tested. It offers all of the advantages of glass slides for light microscopy while being thin and flexible enough to cut and sputter coat for SEM.
Application of frustrated total reflection for studying cells in vitro
Authors: Akatov V. S. 
Published: August 2011

SUMMARYA mathematical analysis of the dependence of the light flux scattered upon frustrated total reflection (FTR) on the angle of incidence of the light beam is presented for monolayers of spread and spherical cells. It is shown that using these relationships it is possible to estimate the refractive index of hyaloplasm at cell‐substrate contacts and to study the flattening of the cell surface facing the glass. Analysis of FTR for single cells is presented. A condition is given that must be fulfilled for the brightly shining regions of the cell to be interpreted as the sites of attachment of the cell surface to glass. The condition defines the range of angles of incidence at which FTR does not depend on the optical properties of the cytoplasm portion being at a distance from the glass. The fulfillment of this condition is necessary for spectroscopic and ellipsometric studies of cell surface contacting the glass, by means of FTR. The conclusions are confirmed by experimental data. A peculiarity of light scattering by cells, associated with the coherence of the incident light beam is discussed.
Analysis of coal blends by automated microscopy
Authors: Lee James B. 
Published: August 2011

SUMMARYThe relative efficiency of coal blend analyses by automated reflectance measurement techniques is compared with an optimum point counting method. The influence of overlapping reflectance distributions and the advantage of image analyser systems over point reflectance measurements are evaluated. Automated point reflectance measurement techniques are feasible for coal blend analysis provided the measurement time is sufficiently small, while image analyser instruments can gain an advantage by reducing the particle top size in the specimen preparation.
Critical‐point drying versus freeze drying for scanning electron microscopy: a quantitative and qualitative study on isolated hepatocytes
Authors: Nordestgaard B. G. , Rostgaard J. 
Published: August 2011

SUMMARYCritical‐point drying and freeze drying were compared both quantitatively and qualitatively as preparative procedures for scanning electron microscopy. Isolated hepatocytes were used as model cells.Nomarski differential interference contrast microscopy was used for light microscopic measurements of the hepatocytes in the unfixed, the glutaraldehyde fixed, the glutaraldehyde + OsO4 fixed, the critical‐point dried and the freeze dried states. Critical‐point dried hepatocytes were found to shrink to 38% of glutaraldehyde + OsO4 fixed volume, whereas optimal freeze dried hepatocytes (frozen in water saturated with chloroform and freeze dried at 183 K for 84 h) were found to shrink to 51% of glutaraldehyde + OsO4 fixed volume. Transmission and scanning electron micrographs of the critical‐point dried cells showed well‐preserved ultrastructure and surface structure. Micrographs of the freeze dried cells showed ultrastructure destroyed by internal ice crystals and surface structure destroyed by external ice crystals.Double‐fixed isolated hepatocytes were shown to swell during storage in buffer and to shrink during storage after critical‐point drying.For low magnification scanning electron microscopy (up to about 3000 times) both critical‐point drying and freeze drying can be used. However, for high magnification scanning electron microscopy, critical‐point drying is superior to freeze drying.
Laser scanning microscopy of surface spread polytene chromosomes
Authors: Kalisch W.‐E. , Whitmore T. , Siegel A. 
Published: August 2011

SUMMARYA new type of a Laser Scan Microscope (Zeiss) was used for the analysis of the band‐interband pattern of polytene chromosomes in Chironomus. In contrast to the previously used techniques of transmission light and electron microscopy, we used differential interference contrast (DIC) in incident light to depict the pattern. Instead of using common squash preparations, we carried out this investigation with surface spread polytene (SSP) chromosome preparations of salivary glands. The combination of techniques used enabled a more detailed light microscopic presentation of polytene structures in individual preparations than conventional techniques used so far for chromosome mapping.
A modification of the chromic tartrate silver impregnation technique for block impregnation of the central nervous system and paraffin wax embedding
Authors: Abadía‐Fenoll F. , Garrido M. V. Ostos , López‐Lendínez J. L. Caballero , Martos R. Carmona 
Published: August 2011

SUMMARYThis paper describes a block silver impregnation technique for the CNS. The procedure, which is quite simple, yields highly consistent and reproducible results.After fixation during 6–10 days in 10% saline formaldehyde, 4 mm thick blocks of brain are treated with chromic anhydride and sodium potassium tartrate solution for 4 days. After this period the specimens are rinsed in 0.75% silver nitrate solution to which 8–10 drops of pyridine per 100 ml of solution have been added. This is followed by impregnation for 4 days at 37°C in silver nitrate‐pyridine solution identical to that used in the previous rinsing step. The impregnated blocks are reduced during 20–26 h in 1% pyrogallol to which 6 ml commercial formaldehyde per 100 ml of solution have been added, followed by dehydration in dioxan and paraffin embedding. Sections no thicker than 30 μm are then cut for histological study.This fundamentally neurofibrillar method reveals: (a) neuronal somata and their processes; (b) synaptic structures; (c) fibre bundles; and (d) cell nuclei and nucleoli.
Comments on the computation of electron wave‐propagation in the slice methods
Authors: Ishikuza K. 
Published: August 2011

SUMMARYThe slice methods developed to calculate dynamical electron diffraction involve an interaction of electrons with each slice and the wave‐propagation between the successive slices alternately. Thus an accurate evaluation of the propagation effect, which is mathematically described in terms of a convolution integral, is indispensable. Three main slice methods are examined from the viewpoint of their accuracy and efficiency on the numerical evaluation of the wave‐propagation. Some difficulties of two real‐space methods are discussed. In conclusion, the FFT multisclie method is the fastest way to obtain the most accurate evaluation of the wave‐propagation at present.
Light microscope based analysis of three‐dimensional structure: Applications to the study of Drosophila salivary gland nuclei. I. Data collection and analysis
Authors: Mathog David , Hochstrasser Mark , Sedat John W. 
Published: August 2011

SUMMARYMany biological structures of interest are large enough that they may be viewed by light microscope methods, yet they are sufficiently complicated that interpretation of what is seen is quite difficult. The salivary gland nuclei from Dipterans are an example of this. Previous attempts at determining the path of the giant chromosomes in these nuclei have depended on the laborious construction of models by hand. A unified Computer Aided Modelling and Analysis system (CAMA) has been implemented, allowing data collection and analysis of structures visible by light microscopy. This system is extendible to the analysis of electron micrographs of serial sections or of other data consisting of images present in a stack.
Light microscope based analysis of three‐dimensional structure: Applications to the study of Drosophila salivary gland nuclei. II. Algorithms for model analysis
Authors: Mathog David 
Published: August 2011

SUMMARYIn Drosophila melanogater there are significant differences in the way the polytene chromosomes are arranged in different nuclei from the same salivary gland (Mathog et al., 1984). Visual inspection of the models of these nuclei was inadequate to delineate all of the features conserved in their structures. In order to bypass this limitation, models of these nuclei were constructed in a format compatible with computational manipulation (Mathog et al., 1985). By applying some simple algorithms to these models, quantitative comparisons were made which revealed otherwise cryptic features common to many nuclei. Given here are the details of several algorithms for describing and comparing the arrangement of the chromosomes within the nuclei.
A computational test for the removal of plural scattering from angle‐resolved energy loss spectra
Authors: Sölkner G. , Schattschneider P. 
Published: August 2011

SUMMARYA recently developed method based on matrix analysis for the removal of plural scattering from angle‐resolved energy loss spectra is tested. A single loss function, Lorentzian in the energy and Gaussian in the angular variable is assumed as input for the test. Multiple scattering probabilities are simulated by summing up n‐fold self‐convolutions of the input function according to the Poisson distribution for incoherent n‐fold scattering. The simulated profile serves as input for the retrieval algorithm, the result of which is compared with the original single‐loss probability. It is concluded that the method is feasible, but not likely to be suited for routine investigations.
Analysis of the irregular planar distribution of proteins in membranes
Authors: Hui S. W. , Frank Joachim 
Published: August 2011

SUMMARYMethods to characterize the irregular but non‐random planar distribution of proteins in biological membranes were investigated. The distribution of the proteins constituting the intramembranous particles (IMP) in human erythrocyte membranes was used as an example. The distribution of IMPs was deliberately altered by experimental means. For real space analyses, the IMP positions in freeze fracture micrograph S were determined by an automatic procedure described. Radial distribution and autocorrelation analysis revealed quantitative differences between experimental groups. These methods are more sensitive than the corresponding optical diffraction or Fourier‐Bessel analyses of the same IMP distribution data, due to the inability of the diffraction methods to separate contrast and distribution effects. A method to identify IMPs on a non‐uniform background is described.
A low cost image and data acquisition system for use with the Vickers M85 scanning microdensitometer
Authors: Glynn P. J. , Larbalestier G. 
Published: August 2011

SUMMARYA simple and inexpensive interface has been constructed between the Vickers M85 microdensitometer and a BBC model B microcomputer. The interface incorporates three sensitivity ranges and enables the production of pseudocolour images of the specimen using the two‐dimensional scanning mode of the M85. The operator can select a 160times256 pixel image with eight colours or a 320times256 display using only four colours. Each colour represents a defined range of transmittance which is software controlled. The image histogram can be displayed and the interval between colours redefined so as to enable contrast stretching. Intervals between colours can be either linear or logarithmic and the images thus obtained can be stored on disc or videotape, or a hard copy can be obtained using a screen dump routine. Two‐dimensional absorption images can thus be obtained at any single wavelength from 400 to 700 nm at normal magnifications of the light microscope.In addition, the system can be used to acquire, store and process data from one‐dimensional scans to obtain quantitative information about variations in optical density within the specimen, so considerably increasing the usefulness of the instrument. Although obviously limited in its capabilities, the system produces images of very high quality and one‐dimensional data of high sensitivity. The interface can be constructed for less than £40. A small modification to one of the M85 circuit boards is necessary to obtain maximum resolution.
A simple device for low temperature polymerization of Lowicryl K4M resin
Authors: Völker W. , Frick B. , Robenek H. 
Published: August 2011

SUMMARYDifficulties concerning low temperature polymerization of Lowicryl K4M have been overcome by constructing and using a simplified polymerization chamber with plastic syringe. Five Beem capsules without cover containing the resin together with the specimen can be inserted into this syringe. For polymerization it is filled with nitrogen gas and closed tightly. Then the device is exposed to long wave UV‐light at 253 K. Using this polymerization chamber Lowicryl K4M resin blocks hardened completely and homogeneously.
Quantitative assessment of three‐dimensional roughness, anisotropy and angular distributions of fracture surfaces by stereometry
Authors: Exner Hans Eckart , Fripan Michael 
Published: August 2011

SUMMARYTechniques for characterizing the geometrical nature of rough surfaces by three‐dimensional descriptors are developed. Measurement of surface coordinates from SEM stereopairs by semi‐automatic stereometry is used to establish the raw data. The surface area, the distribution of size and angles of triangular surface facets, the anisotropy of surface geometry, and surface roughness parameters can be assessed by various computing algorithms. Some typical results obtained for fracture surfaces in a ceramic material are shown. Problems, alternative methods and future developments are discussed.
Contacts in random packings of spheres
Authors: Pomeau Y. , Serra J. 
Published: August 2011

SUMMARYThe first section considers a packing of spheres with the same radius, whose contact zones are reduced to points. The number n of contacts per unit volume is derived from the histogram of the closest distances between couples of discs induced on a plane section. The second section extends the results of the preceding one to the case of slight elasticity. The new formulae differ noticeably from the previous ones. Finally, the case of a population of spheres with different radii is treated, and the two previous approaches are generalized. Once more, two‐dimensional estimates of the 3‐D contacts are provided.