bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning acoustic microscopy visualizes cytomechanical responses to cytochalasin D
Authors: Bereiter‐Hahn Jürgen 
Published: August 2011

SUMMARYThe reactions of XTH‐2 cells (line derived from Xenopus laevis tadpole hearts) to cytochalasin D (CD) were followed using scanning acoustic microscopy (SAM) at 0.9 GHz, fluorescence and electron microscopy. The first reaction to CD which can be detected by SAM is a loss of image contrast, indicating a decrease in acoustic impedance of about 30%. Based on structural changes revealed by staining of actin with TRITC‐phalloidin, and taking theoretical considerations into account, a relationship between impedance decrease and tension in the actin fibrillar system is deduced.
Microcomputer‐aided reconstruction: a system designed for the study of 3‐D microstructure in histology and histopathology
Authors: Yaegashi Hiroshi , Takahashi Tohru , Kawasaki Masami 
Published: August 2011

SUMMARYWe have designed a microcomputer system to reproduce 3‐D tissue structures graphically from serial microscopic sections. The system, based on a Hewlett‐Packard model 310 desktop computer, comprises a floppy disc drive, a hard‐disc that extends the available user memory by adding 40 Mbytes, a colour memory‐mapped graphics display, a graphics tablet and a graphics printer. A set of serial 2‐D images, manually extracted from serial sections using a microprojector, are digitized on the tablet by tracing the contours of the structure of interest; up to ten different structures can be inputted and reproduced using a ‘hidden line’ effect. The software, written mainly in HP‐BASIC 4.0, produces 3‐D pictures of a tissue structure either as a ‘stack of slices' with or without being ‘tiled’ with triangular patches, or in ‘wire framing’. Any angle of rotation around the x, y and z axes is assigned for the image to be reconstructed, allowing the operator to obtain the best perspective. The system also discloses the internal connectivity of an object by reducing the structure to a network diagram; this is especially useful in analysing the topological properties of tissue structure. It is shown how, in some examples, the system contributes to a better understanding of tissue microstructures and their morbid changes and how, as an effective tool in morphology, it will aid future studies of histology and histopathology.
Estimation of organelle water fractions from frozen‐dried cryosections
Authors: Zglinicki Thomas von , Bimmler Martina , Krause Werner 
Published: August 2011

SUMMARYLocal dry mass or water fractions can be measured on frozen‐dried cryosections assuming constant section thickness in the hydrated state and no net water movements and no differential shrinkage during freezing and drying. These assumptions have been tested on a model consisting of isolated rat liver mitochondria in an albumin matrix with a concentration similar to the dry mass concentration of the cytoplasm.The dry mass concentrations of mitochondria before freezing as measured by interference microscopy and after freezing and freeze‐drying of the sections as measured by X‐ray microanalysis and scanning microdensitometry are shown to be equal as long as the ice crystals in the medium are smaller than about 100 nm. It is concluded, therefore, that the above‐mentioned assumptions could also hold for the cryopreparation of cells and tissues.
An evaluation, by Fourier analysis, of some of the errors introduced in reflectance measurements
Authors: Marcos C. , Virgos J. M. , Nicieza C. G. 
Published: August 2011

SUMMARYIn order to evaluate the errors which can be introduced in the measurement of reflectance, we have made a study of data obtained for several minerals and in two immersion media on turning the microscope stage to a succession of positions relatively orientated by 45°. Fourier analysis of the results allows an estimate of the different errors as a function of the periodicity with which they appear on a full rotation of the stage.The mean magnitude of two of the Fourier coefficients is shown to provide a measure of the quality of the measurements further allowing evaluation of the equipment used, the orthogonality of the sample in relation to the incident light, and other errors of different periodicity.
What has the Penrose tiling to do with the icosahedral phases? Geometrical aspects of the icosahedral quasicrystal problem
Authors: Mackay A. L. 
Published: August 2011

SUMMARYThe Penrose tiling is indeed a geometrical model appropriate for the description of the phenomena of icosahedral quasicrystals, although it is probably a related example, rather than the central theory itself, but many aspects of the theory remain to be developed. The transition from X‐ray crystal structure analysis (XRCSA) to high resolution electron microscopy (HREM) as the paradigmatic method for the investigation of crystal structures has facilitated this development and promises other advances from classical crystallography.
High‐resolution electron microscopy of Al‐Mn‐Si icosahedral and Al‐Mn decagonal quasicrystals
Authors: Hiraga K. , Hirabayashi M. , Inoue A. , Masumoto T. 
Published: August 2011

SUMMARYAl‐Mn‐Si icosahedral and Al‐Mn decagonal quasicrystals have been studied by high‐resolution electron microscopy. High‐resolution micrographs of the Al‐Mn‐Si icosahedral quasicrystal taken with the incident beam along the five‐, three‐ and two‐fold symmetry axes are well interpreted on a three‐dimensional Penrose tiling model. An image of the Al‐Mn decagonal quasicrystal with the incident beam parallel to the ten‐fold symmetry axis shows a pattern of an aperiodic tiling with two types of rhombs which can be distinguished from the Penrose tiling using matching and inflation rules. The Al‐Mn decagonal quasicrystal examined coexists coherently with that of icosahedral symmetry exhibiting a definite crystallographic orientation relationship.
Quasicrystalline grain boundary precipitates in aluminium alloys through solid‐solid transformations
Authors: Cassada W. A. , Shiflet G. J. , Poon S. J. 
Published: August 2011

SUMMARYWe have observed the formation of icosahedral quasicrystals of Al‐Mg‐Zn, Al‐Mg‐Cu, Al‐Li‐Zn and Al‐Li‐Cu by low temperature annealing of solid solution alloys. The icosahedral phase particles form at the grain boundaries of the matrix alloys. The orientational relationships between the icosahedral crystallites, their corresponding Frank‐Kaspar phase particles and the aluminium matrix are reported. The stability of the icosahedral phases is also discussed. Finally, the importance of grain boundary icosahedral phase particles to the physical properties of commercial aluminium alloys is pointed out.
Techniques for combining light microscopy and scanning electron microscopy: a survey of the literature
Authors: Wouters C. H. 
Published: August 2011

SUMMARYA survey of methods combining light microscopy and scanning electron microscopy is presented. A simple correlation is made when two preparations from adjacent parts of one specimen are investigated in two different microscopes. A more sophisticated method is the consecutive investigation of one specimen with two microscopes. A major problem in this method is the relocation of the area of interest. Several authors have presented solutions for this problem. It is preferable when one preparation is investigated in only one instrument, combining the two microscopical (LM and SEM) techniques, thus making relocation redundant.
Experimental conditions affecting coherent bremsstrahlung in X‐ray microanalysis
Authors: Vecchio Kenneth S. , Williams David B. 
Published: August 2011

SUMMARYCoherent bremsstrahlung (CB) peaks from several metallic crystals have been observed in X‐ray spectra obtained in the analytical electron microscope. The dependence of CB peaks on certain microscope and specimen parameters was studied with the aim of being able to distinguish CB peaks from small elemental peaks in the X‐ray spectra. It was found that although CB generation is unavoidable in thin crystals, careful choice of experimental conditions allows the detection of CB to be controlled and minimized.
Influence of some practical factors on background extrapolation in EELS quantification
Authors: Liu D‐R. , Brown L. M. 
Published: August 2011

SUMMARYThe detectability of a minor element with EELS in a STEM is of great interest. This paper first describes errors resulting from a conventional background extrapolation scheme and other faults in the collected spectra which in effect greatly reduce the seemingly good signal to noise ratio of a spectrum and therefore impose much more stringent statistical counting requirement on spectra if a small amount of element is to be quantified with good accuracy. Secondly, the systematic variation of the index r of the power law background fitting curve of an ionizatoin edge tail is discussed. Its effect on the detectability of a minor element is analysed. It puts a lower limit on the detectability of an element, however many counts are accumulated. Also a scheme is proposed of some non‐conventional linear least squares fits by which one might suffer from less quantification error due to background extrapolation and achieve lower detectability of a minor element.
Electron beam modifications of InP surfaces
Authors: Milne R. H. , Fan T. W. 
Published: August 2011

SUMMARYInP surfaces have been modified by using the intense electron beam of a V.G. HB501 STEM and subsequently examined in the same instrument using the reflection microscopy geometry. The surface changes can be divided into two parts; first, a fairly local removal of material, and second, more widespread effects including faceting and the formation of an oxide layer which extends for several microns around the point of incidence of the electron beam.
Preparation of the mammalian organ of Corti for scanning electron microscopy*
Authors: Davies Stephen , Forge Andrew 
Published: August 2011

SUMMARYThe effect of various standard tissue preparation procedures for scanning microscopy on the morphology of the mammalian organ of Corti has been examined. Comparison was made of (i) different fixatives: glutaraldehyde (GA) alone, osmium (Os) alone, GA and Os together and GA followed by Os; (ii) freeze‐drying (FD) versus critical point‐drying (CPD); (iii) ligand binding of osmium with thiocarbohydrazide (TOTO procedure) versus sputter coating to provide a conductive coat. Results were assessed in terms of known structural parameters in fresh tissue. It is shown: (i) that double fixation, either GA, Os together or GA followed by Os, consistently produced less tissue distortion than either fixative alone, (ii) that FD produced less shrinkage of the tissue than CPD, and (iii) that the TOTO procedure appeared to rigidify the tissue and enhanced preservation of the morphology.
Time lapse video microscopy using an animation control unit
Authors: Allen T. D. 
Published: August 2011

SUMMARYA system for time lapse video microscopy incorporating an edit recorder and animation control unit is described, allowing both colour recording, forward and reverse playback without synchrony bars, and the identification of each individual frame recorded. This is achieved by using the edit recorder, controlled by the animation unit to produce continuous series of insert edits using the preroll facility of the recorder. A feature of this system is the preview of the last hour' s recording which is constantly played as the preroll of the edit recorder. Tissue culture flasks modified for stable focus are also described.
Scanning low energy electron loss microscopy (SLEELM)
Authors: Gomati M. M. El , Matthew J. A. D. 
Published: August 2011

SUMMARYHigh resolution scanning low energy electron loss imaging of a well characterized system of W on Si is demonstrated in reflection geometry at a primary electron energy Ep of 740 eV and spatial resolution of 3 μm. Characteristic losses below 60 eV are chosen to examine contrast between two types of regions (tungsten and silicon dominated, respectively). By differencing between a maximum in loss intensity and an adjacent trough, high quality chemical images are obtained with contrast far superior to Auger electron images produced in comparable times. It should be noted that, in contrast to scanning Auger microscopy, the spatial resolution of SLEELM is limited only by the profile of the incident beam. In addition, the technique is readily capable of chemical analysis at the surface of bulk specimens. A further advantage of low electron loss imaging is that the depth resolution may be varied by altering the primary electron energy, with the possibility of bridging the gap between Auger electron microscopy and X‐ray microprobe analyser. Possible disadvantages of the technique lie in the weakness of the elastic backscattering which is essential to observe the losses in reflection geometry, and the possibility of overlapping low energy characteristic loss peaks, an effect which is, however, less bad than for low energy Auger peaks. It is shown that electron probes with characteristics rather different from those currently used in Auger microscopes are required to optimize the technique, but that SLEELM has the potential to be a very useful form of surface microscopy which will complement other surface imaging techniques.
Scatter diagrams in energy analysed digital imaging: application to scanning Auger microscopy
Authors: Gomati M. M. El , Peacock D. C. , Prutton M. , Walker C. G. 
Published: August 2011

SUMMARYIn order to improve methods for the systematic characterization of inhomogeneous materials the procedures of multi‐spectral imaging and scatter diagram construction have been deployed. Although the techniques described are relevant to all instruments which detect signals on several different information channels (e.g. wavelength or energy analysed optical, X‐ray or electron imaging), they are illustrated with scanning Auger microscopy (SAM). The construction and use of bivariate correlation diagrams is described by reference to simple samples consisting of patterns of Al film upon Si substrates. The method is then applied to LaNi5 and GaInAs samples each with different signal/noise ratios and chemical characteristics. The software windowing of scatter diagrams by computer combined with presentation of false colour images is demonstrated. The multi‐spectral Auger mapping (MUSLAM) procedure thus evolved is demonstrated to be a powerful, general analytical technique for characterizing the number, abundance and chemistry of each type of region in the surface of an inhomogeneous solid.
A simplified ‘sandwich’ technique for in situ embedding and perpendicular sectioning of monolayer cultures of human skin fibroblasts
Authors: Govaerts P. J. , Bernaer I. I. , du Caju M. V. L. , Jacob W. A. 
Published: August 2011

SUMMARYIn the processing of cell cultures, grown as a monolayer in tissue culture dishes for electron microscopy, the sectioning of the monolayer is an essential step. The monolayer can be sectioned either parallel or perpendicular to the plane of growth. Several methods for the perpendicular way of sectioning have already been described. We propose a simplified method in which the monolayer is sandwiched between two layers of resin, one of which is a pre‐polymerized block, the other being a layer of resin, applied at a second stage. Sectioning of this ‘flat embedded’ specimen yields thin sections perpendicular to the plane of growth of the monolayer without elaborate orientating procedures. The advantage of this procedure is that it can be done using only routine embedding techniques, avoiding special materials or complex manipulations. This sandwich technique provides an excellent mechanical fixation of the monolayer and protects it against external damage.
Dark‐field electron microscopy of unstained biological materials embedded in Nanoplast
Authors: Frösch Dieter , Westphal Christel , Bauer Richard 
Published: August 2011

Extremely thin sections of unstained materials (beef liver catalase, double‐stranded calf thymus DNA, horse spleen ferritin and mammalian skeletal muscle), embedded in the water‐soluble melamine resin Nanoplast FB101, were studied by dark‐field electron microscopy and electron spectroscopic imaging.While ferritin molecules so recorded show 04 and 09 nm lattice fringes within the crystalline iron core, double‐stranded DNA shows a helical repeat with a spacing of 34 nm.The gain in resolution of structural detail reported here is probably due mainly to the reduced section thickness as compared to traditional thin‐sectioning techniques. As we reported earlier (Frösch & Westphal, 1984), melamine resins can be sectioned extremely thinly (<10 nm) and observed without a supporting film, making them especially suitable for dark‐field electron microscopy.
Upside‐down etching; a simple method for reducing unetchable sediment during deep‐etching of fresh untreated tissues
Authors: Shibata Y. , Izumi T. , Yamamoto T. 
Published: August 2011

SUMMARYA simple new method of deep‐etching, ‘upside‐down etching’, has been developed in an attempt to obtain clearer images or replicas, especially of fresh, untreated biological tissues. During etching, specimens were kept facing downwards and shaken periodically so that non‐volatile materials in the subliming ice could fall out of the frozen tissue. This improvement leads to a considerable reduction of sedimented debris of unetchable materials on ‘true’ membrane surfaces, as well as in the cytoplasm exposed by deep‐etching.
A simple method of measuring the thickness of semi‐thin and ultra‐thin sections
Authors: Bedi K. S. 
Published: August 2011

SUMMARYThe exact measurement of the thickness of semi‐thin and ultra‐thin sections is of importance for some stereological methods. Although section thickness can be measured with great precision and accuracy using suitable microinterferometers, such instruments are expensive and not easily available to many laboratories. This paper describes a simple method of measuring the thickness of sections actually used for stereological counting procedures. It involves the division of any given section into two portions, one of which is used for the counting procedures. The other portion is re‐embedded and re‐sectioned through its thickness making it a simple task to measure its thickness.
Failure analysis of plastic encapsulated components—the advantages of IR microscopy*
Authors: Brown J. , Footner P. K. , Richards B. P. 
Published: August 2011

SUMMARYThis paper demonstrates that the use of an IR microscope in non‐destructive failure analysis of plastic encapsulated devices overcomes many of the problems previously associated with conventional failure analysis techniques. Moreover, the devices are amenable to subsequent examination and testing. Its advantages are highlighted in a number of case histories, concerning bond quality, corrosion and features of poor processing. The consequential modification to failure analysis methodology and its applicability to VLSI devices are discussed.
The projection of a negatively‐stained filamentous object down its central axis as revealed by image reconstruction from tilt series
Authors: Seymour J. , DeRosier D. J. 
Published: August 2011

SUMMARYHelical reconstructions of negatively stained biological objects contain distortions arising from filament flattening and the non‐cylindrical profile of the stain envelope. Current methods of estimating flattening do not make full use of the information available in electron micrographs. We have applied the more rigorous approach of reconstructing the density profile from tilt series using digital image processing techniques.Tilt series were collected for tobacco mosaic viruses (TMV) and seven independent reconstructions were calculated using equatorial data out as far as ∼1/9·3 nm—1. They indicated that the filaments were flattened with an axial ratio of about 2·4:1, which was probably closer to 3:1 in the original specimen, because the limited resolution caused flattening to be underestimated. The stain envelope around TMV and some indication of the underlying carbon substrate were also observed.This information could enable correction factors for flattening to be developed, which could be useful when calculating helical reconstructions or indexing helical diffraction patterns. This method could also be extended to non‐equatorial layer planes, which would provide three‐dimensional information on a wide range of macromolecules that possess a one‐dimensional repeat.
Mass loss rate in collodion is greatly reduced at liquid helium temperature
Authors: Lamvik M. K. , Kopf D. A. , Davilla S. D. 
Published: August 2011

SUMMARYThe mass thickness of collodion films has been monitored at several temperatures, under conditions typical of electron microscopy, through the use of an electron energy loss spectrometer. Compared to room temperature, only a five‐fold reduction in the rate of mass loss was observed through the use of a commercial liquid nitrogen cooled stage; in contrast, the rate of mass loss was reduced more than one hundred fold when these films were held at liquid helium temperature.
High spatial resolution secondary ion imaging and secondary ion mass spectrometry of aluminium‐lithium alloys
Authors: Williams D. B. , Levi‐Setti R. , Chabala J. M. , Newbury D. E. 
Published: August 2011

SUMMARYSamples of aluminium‐lithium alloys have been observed by scanning ion microscopy and analysed by secondary ion mass spectrometry. The high signal‐to‐noise ratio of the positive secondary lithium ion opens up the possibility of both high resolution imaging and microanalysis of lithium distributions in aluminium and other materials. Some of the problems encountered due to sample preparation are discussed and ion images of both the artefacts and the true lithium distribution are shown.
A Monte Carlo calculation of secondary electrons emitted from Au, Ag and Cu
Authors: Suichu Luo , Yongsheng Zhang , Ziqin Wu 
Published: August 2011

SUMMARYMonte Carlo calculation of slow secondary electrons (SE) has been performed with a hybrid model of the exponential decay law and cascade process. The contributions of both valence electron excitation and core electron excitation have been considered. The calculated yield, energy distribution, angular distribution and depth distribution for Au, Ag and Cu (28 keV, at normal incidence) are in agreement with the experimental results and better than those previously reported.
Single‐electron effects observed with a low‐temperature STM
Authors: van Bentum P. J. M. , van de Leemput L. E. C. , Smokers R. T. M. , van Kempen H. 
Published: August 2011

SUMMARYWe have used a low‐temperature scanning tunnelling microscope to study the effect of the Coulomb charging energy on the tunnelling behaviour of low capacitance point‐contact junctions. The tunnelling I‐V characteristics between a tungsten tip and various materials, such as stainless steel, aluminium, carbon and YBa2Cu3O7‐δ, show a quadratic behaviour at low voltages and a displaced asymptotic behaviour at high voltages. The I‐V characteristics can be quantitatively understood using the model of single‐electron tunnelling induced by the Coulomb blockade. The capacitances of this type of point‐contact tunnel junctions are in the 10−18 F range, and are adjustable by varying the distance between tip and surface. These capacitances are at least two orders of magnitude lower than can presently be achieved by electron lithography.In a series configuration of two low‐capacitance tunnel junctions, with an isolated small particle as a common electrode, we have observed the so‐called Coulomb staircase, due to the quantization of the charge on a single small particle.The experimental results are in good agreement with semi‐classical Monte‐Carlo simulations.The low capacitance of an STM assembly can cause a serious complication in the interpretation of low temperature spectroscopic data. We will discuss the implications for the measurements on superconductors, and for the case of inelastic tunnelling spectroscopy.