bluuebunny/crossref_metadata_2025_split huggingface dataset:
Averaging of periodic images using a microcomputer
Authors: Squire John M. , Luther Pradeep K. , Agnew Gerard D. 
Published: August 2011

SUMMARYA system based on a commercial microcomputer and a commercial image‐capturing TV interface is described which carries out both real space and conventional Fourier transform‐based image averaging procedures. Various real space manipulations are described for handling images with either one‐dimensional or two‐dimensional periodic features. In certain cases, real space averaging procedures have many advantages and are recommended to those not familiar with the mathematics of methods based on Fourier transformation. In other cases Fourier transformation processes are necessary and these also have been implemented on the microcomputer. They can be used to determine periodicities, to produce two‐dimensional average images or as a basis for three‐dimensional reconstruction. Examples showing the principles of application of these methods use appropriate images from electron micrographs of muscle and collagen.
A new method for the two‐dimensional analysis of bone structure in human iliac crest biopsies
Authors: Garrahan N. J. , Mellish R. W. E. , Compston J. E. 
Published: August 2011

SUMMARYA new method is described for the analysis of the two‐dimensional structural pattern of trabecular bone in human iliac crest biopsies. 8 μm thick undecalcified sections stained with the von Kossa technique were examined at a magnification of ×9. Using an Ibas II image analyser, the ratio of nodes to free ends and the length of different strut types (cortex to free end, node or cortex, free end to free end and node to node, loop or free end) expressed as a percentage of total strut length were assessed.The reproducibility of the method was good for most of the measured indices but inter‐observer and inter‐section variation were greater. Comparison of biopsy sections obtained from eleven young healthy control subjects and eleven patients with hepatic osteoporosis revealed a significantly higher node to free end ratio, node to loop and node to node strut length and significantly lower cortex to free end and free end to free end strut length in the controls. No significant differences were seen in node to free end, cortex to cortex or cortex to node strut length. This approach to trabecular bone structure analysis should prove useful in determining patterns of bone loss in health and disease and in examining the effects of treatment on bone structure in osteoporosis.
A versatile light microscope heating stage for biological temperatures
Authors: Lowndes R. H. , Hallett M. B. 
Published: August 2011

SUMMARYA light microscope heating stage suitable for biological temperatures is described. A novel feature of the design is the use of cupro‐nickel foil heaters (0.1 mm thick). With a temperature sensor mounted on the slide clip and a temperature controller unit, this apparatus maintains a temperature of 310 K with a precision of 0.1 K. The apparatus is inexpensive, reliable, not confined to use with one microscope and does not interfere significantly with the stage movement or optical alignment.
Generalized associated point methods for sampling planar objects
Authors: Jensen E. B. , Sundberg R. 
Published: August 2011

SUMMARYFor estimation of the mean number of objects per unit area from observations in a bounded region (sampling window) T in the plane, a generalized associated point method is discussed. By this method, m points are associated with each object, and an object with k associated points inside T is counted with weight k/m. A general formula for the variance of the estimator is derived and explicit expressions are given for Poisson and hard‐core models for the spatial distribution of objects in the plane.
Correction of window size distortion of crack distributions on plane sections
Authors: Attiogbe Emmanuel K. , Darwin David 
Published: August 2011

SUMMARYThe scanning electron microscope (SEM) has been used to measure crack distributions on the surfaces of cement paste and mortar. However, true distributions of cracks (or straws, needles, etc.) on a plane section may not be obtained directly if only a portion of the plane section is visible within the field of view (window), as is the case with an SEM. The procedures used to estimate the true distributions are presented. These procedures are based on the concepts of geometrical probability and statistics. Relationships are established between the observed and the true distributions, and iterative techniques are employed to estimate the true distributions. For a given window height, a guideline is provided to determine if the window size distortion needs to be corrected. It is shown that the total length of cracks per unit area on a plane section is not affected by the window size.
Information recovery in missing angular data cases: an approach by the convex projections method in three dimensions
Authors: Carazo José María , Carrascosa José L. 
Published: August 2011

SUMMARYWe have studied the method of projections on to convex sets (POCS) for the restoration of three‐dimensional signals, especially applied for the degraded information obtained in three‐dimensional (3‐D) reconstructions by electron microscopy due to the limited tilting angular range of the sample that is obtainable in practice. A computer generated specimen has been used as a test object. Several noise levels were added to the specimen, obtaining signal‐to‐noise ratios (signal power/noise power) of between 12 and 0·5 dB. Different missing data angular regions of 30° and 10° zenithal angle have been considered. Our results illustrate the possibilities of POCS to restore incomplete 3‐D data in the absence and the presence of noise, and offer ways for further applications to improve the quality of 3‐D reconstructions based on real data.
Determining nucleolar multiplicity and cell number from sectional data
Authors: Gramsbergen A. , Kok L. P. , Poortema K. , Schaafsma W. 
Published: August 2011

SUMMARYThe occurrence of more than one nucleolus within the cellular nucleus (polynucleolarity) is a well‐known phenomenon during the proliferative cell cycle, both under normal and pathological conditions (e.g. neoplasia). It can also be observed in neuronal nuclei at early stages of their maturation. Polynucleolarity merits investigation for cytological reasons.In an histological section, the observed number of nucleoli in a nucleus may be smaller than the actual number. In order to estimate the true distribution of the number of nucleoli per nucleus from the observed distribution, the mathematical relation between these distributions is derived (Section 4) on the basis of rather restrictive (Sections 3 and 11) stereological assumptions (Section 2). It is indicated how these distributions can be estimated from the data available and how the statistical uncertainties involved can be expressed (Sections 5, 6 and 7).This paper arose from making cell counts (Section 1). Two methods may be applied: (1) all visible nuclear profiles are counted, (2) nuclear profiles are only included if at least one nucleolus is visible in the section. We recommend a combination of these two methods (Section 8). An advantage of our theory for determining cell number (Section 9) is that one can often manage without the rather restrictive stereological assumptions needed hitherto.The advantage of expressing statistical uncertainties in estimated nucleolar multiplicity probabilities and cell numbers is indicated (Section 10).
The grid‐cell‐culture technique: the direct examination of virus‐infected cells and progeny viruses
Authors: Hyatt A. D. , Eaton B. T. , Lunt R. 
Published: August 2011

SUMMARYWe describe a method for the structural analysis and identification of viruses, without purification or concentration steps which could alter virus morphology. Virus‐infected cells grown on carbon‐Parlodion‐coated electron microscope grids release large numbers of progeny viruses which adsorb to the surface of the grid and are revealed by negative staining. The technique is rapid, sensitive and can be used at three levels. (1) Negative staining of whole cell preparations revealed both extracellular and intracellular viruses or nucleocapsids beneath the plasma membrane; (2) non‐ionic detergent extraction of cells infected with certain viruses reveals cytoskeleton‐associated, virus‐specific structures normally only observed after thin sectioning; (3) cultures prepared by either procedure are suitable for colloidal gold immunological studies. Extracellular and cytoskeletal‐associated viruses were heavily and specifically labelled with gold. The results indicate that the technique may be used to rapidly identify unknown viruses on the basis of size, topography, morphology and mode of maturation from the infected cell, as well as the presence of characteristic intracellular cytoskeletal‐associated structures. The technique also has potential use in the sero‐grouping and sero‐typing of viruses with specific monoclonal antibodies.
Floating on a water bath and mounting glycol methacrylate and hydroxypropyl methacrylate sections influence final dimensions
Authors: Gerrits P. O. , van Leeuwen M. B. M. , Boon M. E. , Kok L. P. 
Published: August 2011

SUMMARYThis paper reports the dimensional changes occurring in the different steps of the histoprocessing of tissues for light microscopy. Two water‐miscible methacrylates used for embedding, namely 2‐hydroxyethyl methacrylate and 2‐hydroxypropyl methacrylate, were investigated. It was found that during stretching on the water bath and in the mounting step considerable size changes occur, which are of the same magnitude as during the dehydration step of histoprocessing. The final dimensions of the sections and of microscopic images are dependent on the response to surface tension at the water surface and mounting of the glycol and hydroxypropyl methacrylate sections, respectively. Between the two resins under study, significant differences in the size of the resin sections, with and without embedded liver tissue, were found. It is shown that the temperature at which the sections are mounted is of great importance. These observations indicate the importance of standardizing histotechniques if morphometry is to be applied.
Reflection electron microscopy methods for the study of surface structure
Authors: Hsu Tung , Cowley J. M. , Peng L.‐M. , Ou H.‐J. 
Published: August 2011

SUMMARYThe techniques of reflection electron microscopy (REM) using TEM instruments and scanning reflection electron microscopy (SREM) using STEM instruments have been explored as means for the observation of surface structure with high spatial resolution, better than 1 nm in each case. Under the ordinary environment of a commercial TEM instrument, we have studied the contrast in REM images of atomic steps and made comparison with the calculated results from the multi‐slice dynamical diffraction theory. Comparison has also been made between the REM images of defects and the calculated images based on the column approximation. The influence of surface resonances on the contrast has been investigated. By SREM performed in a modified HB5 STEM with attached high vacuum preparation chamber, we have observed the formation of periodically distributed Pd particles on the surface of cleaved MgO.
A rapid methyl salicylate clearing technique for routine phase‐contrast observations on female meiosis in Solanum
Authors: Jongedijk E. 
Published: August 2011

SUMMARYA rapid clearing technique, involving methyl salicylate clearing and phase‐contrast microscopy, that enables large‐scale observations on meiosis and embryo sac development in intact ovules of potato, was developed. With high resolution phase‐contrast optics the details observed in cleared ovules were as well defined as in microtome sections and ‘abnormalities' associated with desynapsis and 2n‐megaspore formation were readily detected.In potato this ovule clearing technique offers certain advantages over earlier clearing and staining‐clearing techniques and permits bulk preparation of ethanol (70%) stored ovaries shortly (1·5–2 h) before observation.
Computer automated cell size and shape analysis in cryomicroscopy
Authors: Diller Kenneth R. , Aggarwal Shanti J. 
Published: August 2011

SUMMARYComputer vision techniques have been developed for quantitative analysis of size and shape changes in cells frozen on a cryomicroscope. The analysis is based on implementation of standard serial edge detection algorithms in conjunction with a shape transform to isolate individual cells in complex scenes which may include adjacent and overlying ice crystals. In the present study the sensitivity of the automated analysis procedure is evaluated for images obtained by various microscope optical systems for progressive degrees of subject blurring by defocusing. Size measurements in calibration trials for freezing latex spheres with extracellular ice in the field of view were least sensitive for bright field images, although the most consistent data was obtained by differential interference contrast microscopy. In all cases phase contrast images produced the least accurate data. An example analysis is presented for the freezing of pancreas β‐cells.
The inhomogeneity of the icosahedral phase in Al‐Mn and Al‐V
Authors: Knowles K. M. , Stobbs W. M. 
Published: August 2011

SUMMARYThe inherent differences between the various current structural models for the determination of the scattering behaviour of icosahedral materials are reviewed with the conclusion that the nature of their apparently characteristic inhomogeneity needs further clarification. Here it is shown that the dark field reflection and deviation parameter dependence of transmission electron microscope (TEM) contrast variations can be used to provide useful qualitative evidence for the nature of quasicrystal inhomogeneities. Results obtained using the technique are discussed for the icosahedral phases i‐(AlMn) and i‐(AlV).
A model for calculating secondary and backscattered electron yields
Authors: Joy David C. 
Published: August 2011

SUMMARYImages in the scanning electron microscope (SEM) are formed from both low‐energy secondary, and high‐energy backscattered, electrons. The quantitative interpretation of SEM images therefore requires a model which can predict the magnitude of both of these signal components for a specimen whose geometry and chemistry is known. It is shown that the combination of a simple electron diffusion model with a Monte Carlo trajectory simulation allows both yields to be calculated, simultaneously, with good accuracy. Data, such as the magnitude and energy of the maximum secondary yield, the secondary variation with tilt, and the contribution of backscattered electrons to the secondary yield coefficient, computed from this model are in excellent agreement with experimental data.
Studies of supported metal catalysts using high resolution secondary electron imaging in a STEM
Authors: Imeson D. 
Published: August 2011

SUMMARYAn additional technique for use in the characterization of catalysts by electron microscopy is presented. High resolution secondary electron images obtained in a VG HB501 scanning transmission electron microscope have been used to study the surface topography of catalysts consisting of small metal particles on high surface area carbon supports. Surface features down to nanometre dimensions can be seen, allowing the examination of micropores in the support as well as larger pore structures. The results are compared with pore size distributions determined by gas adsorption methods, and are shown to yield valuable additional information. In addition, the method in principle allows examination of the locations of small metal catalyst particles on the support.
Computer‐assisted three‐dimensional reconstruction technology in plant cell image analysis: applications of interactive computer graphics
Authors: Tuohy M. , McConchie C. , Knox R. B. , Szarski L. , Arkin A. 
Published: August 2011

SUMMARYSequences of more than 100 serial thin sections were cut of entire generative cells of pollen of Brassica campestris. Using transmission electron micrographs, outlines of the cell nucleus, vacuoles and mitochondria were digitized and stored on disc using the Carl Zeiss‐Kontron Videoplan Image Analysis System. The data collected concerned the geometry of cuts and logical collection of cuts into structures, both internal and external. A data translation and surface generation system was established to transfer these data to a VAX‐751 computer to establish an interface to the Intergraph's Interactive Graphics Design System (IGDS). Definition of the surfaces is based on the translated boundaries and structural configuration, enabling three‐dimensional visualization of: (a) the wireframe model; (b) the overall model with removed hidden lines, including colour or monochrome shading; and (c) the shaded image of the internal structures with superimposed wireframe representation of the external structures.
The construction and operation of a simple inexpensive slam freezing device for electron microscopy
Authors: Allison David P. , Daw C. Stuart , Rorvik Marie C. 
Published: August 2011

SUMMARYA simple and inexpensive slam freezing device has been constructed that allows consistently good rapid freezing of uncryoprotected tissue. The device employs a dry liquid‐nitrogen‐cooled copper surface and a slamming plunger designed to provide rapid and uniform tissue to metal contact.
A new technique for obtaining large platinum‐carbon replicas
Authors: Adachi Eijiro , Nakatani Toshio , Hashimoto Paulo H. 
Published: August 2011

SUMMARYA problem often encountered in freeze‐fracturing is that platinum‐carbon replicas roll up or are broken into fragments during tissue digestion and replica washing. In replicas damaged in these ways, tissue orientation and cell identification are difficult. In order to prevent such damage, methods have been introduced of replica strengthening by coating them with plastic films (Steere, 1957; Willison & Rowe, 1980; Stolinski et al., 1983), or with an additional layer of silver or gold (Robards & Umrath, 1978; Robards & Sleytr, 1985). A disadvantage of these methods, however, is that the additional layer must be removed before the replicas can be examined under the electron microscope. Removal of the additional layer results in loss of image quality. A reinforcing plastic film may not be completely digested by the tissue solvent and will then contaminate the replica, while the silver technique requires a silver evaporation source to be present in the vacuum chamber. Instead of replica strengthening methods, some authors recommend putting replicas carrying tissues, which have been partially digested by bleach (Pearce, 1983) or chromic acid (Fetter & Costello, 1986), onto carbon‐coated gold grids and then floating them on chromic acid. However, neither this method nor the replica strengthening method assure the production of large unrolled replicas. Moreover, gold grids are rather expensive.
Automatic focusing by correlative methods
Authors: Vollath D. 
Published: August 2011

The possibility of focusing images by the autocorrelation function is explained. It can be shown that these techniques are less sensitive to disturbances by noise than others. Furthermore, focusing criteria derived from autocorrelation functions have different responses to image contrast.It has been shown that these focusing criteria can be determined using binary images and applying the laws of stochastic ergodic metrology. This leads to a large reduction in computing time.Moreover, an attempt was made to focus by means of binary images determined by simple segmentation. The experimental results show that such a focus criterion operates quite well. The criterion offers the advantage that brightness levels in the image can be chosen selectively for focusing.
Ultrastructure and histochemistry of blue‐green algae freeze‐substituted at 190 K by Nanoplast MUV 116
Authors: Bachhuber Karlheinz , Böhme Herbert , Westphal Christel , Frösch Dieter 
Published: August 2011

A method is presented for the infiltration and embedding of frozen micro‐organisms at a temperature of 190 K by Nanoplast MUV 116, a new UV‐polymerizable embedding medium for electron microscopy. The hardness achieved by UV irradiation in the cold is about 80% of the hardness needed for ultramicrotomy. Final hardening requires a post‐curing step at 333 K for 24 h.Applying this procedure to cyanobacteria, an improved ultrastructural preservation is demonstrated as compared to samples that were embedded in the water‐soluble medium Nanoplast FB 101 at ambient temperatures. Sections of materials treated in this way are suitable for histochemical techniques, such as Thiéry's silver staining method for glycogen.
Laser scanning microscope: Differential phase images
Authors: Horikawa Yoshiaki , Yamamoto Mitsunori , Dosaka Shinichi 
Published: August 2011

SUMMARYA beam‐deflection type laser scanning microscope for differential phase contrast images using the split‐detector technique is developed and the images are obtained in real time (30 images/s).The special optical design allows transfer of the pupil information necessary to the imaging of the differential phase contrast images during beam deflection and the use of acousto‐optic deflectors with the associated correction system enables real time imaging.Differential phase images of surface details of crystals are simply obtained without silver coating or etching, which are indispensable in a normal DIC. Biological specimens are also observed.
Single‐ring polanret phase‐contrast system
Authors: Pluta M. 
Published: August 2011

SUMMARYAn extremely simple, modified polanret phase‐contrast system has been developed. It uses only a single polarizing ring, instead of three zonal polarizers as required in Osterberg's original polanret system (manufactured by the American Optical Corporation). The modified system is much more easily manufactured and its economy of light is twice as good. However, it does require an easily accessible microscope objective exit pupil, where the polarizing ring must be located.
Application of acoustic microscopy to the measurement of some physical parameters of ceramics
Authors: Grosmaire J. , Nongaillard B. , Rouvaen J. M. , Saisse H. , Fevrier H. , Joseph S. 
Published: August 2011

SUMMARYThe scanning acoustic microscope is a valuable tool for the ultrasonic non‐destructive testing of ceramic materials or sintered metals, like titanium compounds. Bulk defects, responsible for the mechanical aging and breakdown of parts, are easily detected and imaged. Moreover, diffuse structures are evidenced in these images, forming a continuous background. In this paper, we present a method which enables the determination of physical parameters, like the density and the bulk grain size of the materials, from this background. This information is extracted, using a statistical approach, from the histograms pertaining to materials with a spectrum of different microstructures, based on a principal component analysis (PCA). It may be noted that the size of the microstructure elements accessible by this method can be lower than the spatial resolution of the microscope.
A LISP‐based image analysis system with applications to microscopy
Authors: Bright David S. 
Published: August 2011

SUMMARYLISPIX is an image processing and analysis system consisting of a sub‐system of image processing commands implemented in FORTRAN and a collection of analysis algorithms implemented in LISP. Examples are given of using the system for microanalysis applications. The processing commands are useful alone for simple tasks. For analysis applications, the LISP programming environment, for which the processing commands are designed, allows rapid development of algorithms and a convenient way to use them. Appendices contain definitions of the most useful commands as well as examples of the LISP algorithms.