bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scanning tunnelling microscopy of graphite‐adsorbed molecular species
Authors: Hubacek J. S. , Brockenbrough R. T. , Gammie G. , Skala S. L. , Lyding J. W. , Latten J. L. , Shapley J. R. 
Published: August 2011

SUMMARYA new variable‐temperature STM has been used to perform studies of the adsorption and ordering of simple polar molecules such as acetone and dimethylsulphoxide (DMSO) on graphite. The primary objective of this work is to obtain fundamental information which can serve as a basis for studies of complex systems. Following exposure of graphite to acetone vapour, STM images show cloudy patches of acetone drifting across the surface, with individual molecules being indistinguishable. Following prolonged exposure, however, an ordered monolayer forms, having triangular symmetry and 2×2 commensurate periodicity relative to the substrate. Similar results are obtained for DMSO on graphite; however, the monolayer is more closely packed and probably incommensurate with the substrate. In a related effort, nitric acid is shown to be an effective chemical etch for creating steps in basal plane graphite. It is hoped that this, and related techniques, will enable the use of STM to study important chemical systems, such as treated fuel‐cell electrodes, which utilize non‐basal plane graphite.
STM of layered‐structure semiconductors
Authors: Henson Tammy D. , Sarid Dror , Bell L. Stephen 
Published: August 2011

SUMMARYWe have used scanning tunnelling microscopy to characterize the layered structure semiconductors MoS2, WSe2 and SnS2. Atomically resolved images as well as spectroscopic data in both tunnelling directions have been obtained for the cleaved surfaces of these materials.
Nano‐machining of gold and semiconductor surfaces
Authors: Packard William E. , Liang Young , Dai Ning , Dow John D. , Nicolaides Ruth , Jaklevic Robert C. , Kaiser William J. 
Published: August 2011

SUMMARYUsing a scanning tunnelling microscope tip formed by cutting a platinum wire, we have modified the surfaces of gold and Hg1‐xCdxTe on a nanometre scale by mechanical contact between the tip and the surface. By using the same tip to form images, we have been able to gain ‘before’ and ‘after’ pictures of surfaces that have been selectively ‘sanded’, controllably ‘chiselled’, and ‘swept’.We have also obtained images taken under glycerin of Hg1‐xCdxTe and of the diluted magnetic semiconductor Hg1‐xMnxTe.
Metal‐induced reconstructions of the silicon(111) surface
Authors: Park Sang‐il , Nogami J. , Quate C. F. 
Published: August 2011

SUMMARYWe have used scanning tunnelling microscopy (STM) to study changes in the structure of the Si(111) surface induced by deposition of the group III metals In and Ga. For both metals, several different ordered reconstructions are seen as a function of coverage. The STM images provide new structural information on each of these reconstructions. With In metal deposition, we have seen the surface reconstructions √3×, √3, √31× √31, √7×√3 and 4×1 as the coverage increases. In the case of Ga on Si(111), we have studied structures that exist up to 0·7 ML. At 1/3 ML, there is a √3×√3 structure identical to that of In. Above 0·3 ML there is a different phase that may correspond to the (6·3times6·3) RHEED pattern reported in this coverage range. This surface tends to grow as triangular islands at higher coverages.
Scanning tunnelling microscopy of biomacromolecules
Authors: Guckenberger Reinhard , Wiegräbe Winfried , Baumeister Wolfgang 
Published: August 2011

SUMMARYWhen imaging biomacromolecules with a STM, coating of specimens with a conductive layer is a convenient preparation method which provides a good rate of success. Utilizing evaporated platinum/carbon as a coating film we have investigated two biomacromolecules of very different appearance. The first of these is the HPI‐layer, a natural two‐dimensional protein crystal with a period of 18 nm, which is found on the surface of the bacterium Deinococcus radiodurans. The second specimen is type IV collagen which forms long triple‐helical strands approx. 1·5nm in diameter. The resulting STM pictures compare very well with electron microscopical images.
A technique for studying the development, metamorphosis and morphology of insects, using projection X‐ray microscopy
Authors: Davies Robert Ll. , Worrill Nicola , Bowen Ivor D. , Harrison Timothy J. , Evans Kenneth T. 
Published: August 2011

SUMMARYA technique is described for studying insect morphology and flight musculature using an X‐ray microscope. We have shown that a resolution of about 1 μm is possible in intact insects. Electron opaque markers have been used to locate cytochemical sites of enzyme activity, and to investigate gross morphology during developmental metamorphosis in Heliothis armigera.
Acoustic microstructure of mature soya bean (Maple Arrow)
Authors: Kolodziejczyk E. , Saurel J. M. , Fernandez‐Graf M. R. , Attal J. , Fryder V. , Saied A. , Dillmann M. L. , Rey V. 
Published: August 2011

SUMMARYThe acoustic microscope is used to visualize the acoustic microstructure of wet soya beans. The microacoustic patterns are correlated with their corresponding scanning electron microscopic and light microscopic images. The results show that the acoustic microscope is convenient for rapid and precise studies of thick specimens and gives structural information on a tissular and on a subcellular scale.
A simple technique for in situ embedding of monolayer cultures in Lowicryl K4M
Authors: BOU‐Gharios G. , Adams G. , Moss J. , Shore I. , Olscen I. 
Published: August 2011

SUMMARYA number of difficulties are encountered in embedding monolayer cultures at low temperature in Lowicryl K4M resin. In this paper we present a simple procedure using Lab‐Tek Flaskettes in which fixation, processing and embedding of monolayer cultures can readily be achieved.
X‐ray microanalysis with continuous specimen cooling: is it necessary?
Authors: Zglinicki Thomas von , Uhrík Branislav 
Published: August 2011

SUMMARYAn X‐ray microanalytical preparation technique using continuous specimen cooling and consisting of cryotransfer of frozen sections into the electron microscope, freeze‐drying of the sections within the microscope and analysis at liquid nitrogen temperature is compared with a more conventional technique characterized by freeze‐drying of sections in a vacuum evaporator with subsequent carbon coating, transfer of frozen‐dried sections through the room air into the electron microscope and analysis at ambient temperature. For this comparison elemental concentrations in mitochondria, in areas of the rough endoplasmic reticulum and in the cytoplasm of rat hepatocytes, were measured.Si is found in abundance in specimens freeze‐dried outside the microscope due to the use of a vacuum evaporator contaminated with pump oil. Radiation damage will be more severe at ambient temperature and is assumed to be the reason for observed differences in S concentration in mitochrondria and the cytoplasm. However, peak‐to‐background ratios for Na, Mg, P, Cl and K are in general the same for both types of preparation.
A perfusion chamber for high‐resolution light microscopy of cultured cells*
Authors: Finch Simon A. E. , Stier Anton 
Published: August 2011

SUMMARYA perfusion chamber suitable for general microscopic work on upright and inverted microscopes with cultured cells is described. The device features a minimal internal volume and large field of view within small outer dimensions. In particular the chamber body is very flat to accommodate large‐aperture condenser and objective lenses. It is constructed of innocuous, sterilizable materials, incorporates permanent seals for the windows, is robust and simple to use.
BASIC programs to compute source densities from autoradiographic cross‐fire matrices
Authors: Cau Pierre 
Published: August 2011

SUMMARYTwo different mathematical procedures to compute source densities from cross‐fire matrices in quantitative EM autoradiography are reported. BASIC programs for a desk‐top microcomputer were written to fit the hypothetical silver grain distribution to the observed real silver grain distribution using a non‐iterative linear process (least‐squares procedure) and an iterative method, which minimizes the chi‐square component between the observed and computed silver grain distributions. The latter procedure uses a Gauss‐Newton algorithm.
Application of freeze‐etch replication for the observation of the cell‐extracellular matrix interface of cultured cells
Authors: Sawada Hajime 
Published: August 2011

SUMMARYIn order to investigate the ultrastructural three‐dimensional relationship between extracellular matrices (ECM) and the plasma membranes of cultured cells, a freeze‐etch replica method was devised.Bovine corneal endothelial cells were cultured on a Collodion film which covered a hole punched in a plastic coverslip, and were quickly frozen with a slammer with their basal surface facing a liquid nitrogen‐cooled copper block. The cells were placed upside‐down in a Balzers freeze‐fracture machine and freeze‐etched, and then platinum‐carbon replicas were obtained.The structure of the ECM‐plasma membrane interface was observed successfully and so this technique provides a new approach for investigating the ECM‐plasma membrane (matrix‐receptor) relationship.
Matschinski's identity and dual random tessellations
Authors: Miles R. E. 
Published: August 2011

SUMMARYVarious aspects of Matschinski's classical identity relating, in a homogeneous ergodic polygonal tessellation, the mean number of vertices, or sides, with the mean number of sides meeting at a random vertex, are discussed. It is shown how any such tessellation has a topological family of dual tessellations. An example given is that of an isotropic random tessellation, all of whose cells are quadrangles; another example has identical distributions of number of vertices and number of sides meeting at a vertex.
Affine integral geometry and convex bodies
Authors: Santaló L. A. 
Published: August 2011

SUMMARYGiven a convex body Q in Euclidean n‐dimensional space, the affine invariant measure of the set of pairs of parallel hyperplanes containing Q is an affine invariant J(Q) of Q, which, for ellipsoids, parallelepipeds and possibly for simplices of any dimensions, is proportional to V−1, where V represents the volume of Q. Consequently, for the kind of bodies mentioned, it is possible to estimate V−1 from its breadth measured in uniform random directions. If the boundary of Q is of class C2, we obtain a set of affine invariants Jh(Q) (h = any integer) which is easily calculable for ellipsoids. In particular, J‐n(Q) coincides with J(Q) and J‐(n+1)(Q) is the affine invariant measure of all pairs of parallel hyperplanes that ‘support’ Q as described by Firey(1972, 1985), Schneider (1978, 1979) and Weil (1979, 1981). For a general convex body Q the values of Jh(Q) cannot be expressed in terms of simple metric invariants (such as volume, surface area, breadth, width) and this justifies the study in the last section of certain inequalities between them.
Expectation formulas and isoperimetric properties for non‐isotropic Boolean models
Authors: Weil Wolfgang 
Published: August 2011

SUMMARYBoolean models Y in R2 and R3 are considered and formulas connecting the quermass densities of Y with the mean values of certain functional of the primary grain are given in the non‐isotropic case. Under symmetry conditions, the mean functionals are interpreted as mixed volumes of convex bodies which are associated with Y. Extremal properties of isotropic Boolean models are deduced from the isoperimetric inequality.
On the coverage problem in higher dimensions with nonuniform density
Authors: Hüsler J. , Glauser K. 
Published: August 2011

SUMMARYConsider the coverage of a k‐dimensional unit cube by n spheres randomly placed according to a density f. Assume that f is non‐uniform, having a unique interior minimum point m in the unit cube with f(m) = 0. We present necessary and sufficient conditions such that the probability that the unit cube is covered at least l times converges to 1 as n → ∞. These conditions depend on the local behaviour of f in the neighbourhood of m and the radii δ of the random spheres.
Morphological and elemental integrity of freeze‐fractured, freeze‐dried cultured cells during ion microscopic analysis
Authors: Ausserer Walter A. , Chandra Subhash , Morrison George H. 
Published: August 2011

SUMMARYThe effects of progressive ion beam bombardment on freeze‐fractured, freeze‐dried cultured cells during ion microscopic (SIMS) analysis were studied with scanning electron microscopy (SEM) and ion microscopy. The freeze‐fracture, freeze‐dry sample preparation method was generally found to preserve cell morphology to a level far exceeding the spatial resolution of the ion microscope, with splitting at the nuclear envelope being the most commonly observed artefact. SEM monitoring of surface topography of an NRK‐49F fibroblast after various ion bombardment doses showed relatively uniform erosion of cellular material, with some apparent selective retention of small cytoplasmic granules. Prolonged bombardment produced no detectable lateral elemental translocation. 41K+/24Mg+ signal ratios from Swiss 3T3 fibroblasts and RBL rat basophilic leukaemia cells were shown to vary generally by less than 10% during the course of extended ion bombardment. GM0415 human skin fibroblasts containing engorged lysosomes characteristic of Hurler's Syndrome were used to evaluate the effects of ion bombardment during a typical analysis session, where ion images of 39K+, 23Na+, 40Ca+ and 24Mg+ are sequentially recorded. This cell line was chosen as a worst‐case system, because these cells are often thinly spread and possess extreme surface topography. Thin cell edges were shown sometimes to sputter away during analysis, giving misleadingly low ion signals from these regions in some 24Mg+ micrographs. Various nonuniform sputtering phenomena occurring in the submicrometre spatial domain had little or no measurable impact on local intensities in ion micrographs, indicating that freeze‐dried, freeze‐fractured cells are sampled in a sufficiently uniform fashion that quantitative ion microscopic evaluations of intracellular elemental levels in the general cytoplasmic or nuclear regions are feasible.
Photometric measurement of small optical path differences
Authors: Roche E. J. , Van Kavelaar R. F. 
Published: August 2011

SUMMARYA photometric method for the measurement of small optical path difference (OPD) is described. The method is based on a computer assisted calibration of the transmitted intensity associated with specific rotations of the calibration device, a Λ/10 compensator. The method has been tested on cleavages of mica and shown to be in excellent agreement with photometer assisted measurements of compensation. Application to the measurement of lateral orientation in Kevlar® 49 aramid fibres is presented.
Lattice fringe studies of (100) defects in enamel crystallites
Authors: Lee DoSuk Duke 
Published: August 2011

SUMMARYLattice imperfections in the structure of shark (Nataprion brevirostrais) enamel crystallites have been studied by means of lattice‐imaging in a high‐resolution transmission electron microscope. Line defects exhibiting various lengths (100–2500 Å) and widths (10–30 Å) and demonstrating phase behaviour different from that of the host crystal were observed along the fringes representing (100) lattice planes.When defect sites were subjected to an electron beam, an annealing process was observed in which the difference in phase contrast eventually disappeared and the defect itself became an intricate part of the (100)‐type lattice planes.A through‐focal series of the defects show a reversal in phase contrast. By examining the contrast behaviour under certain focal conditions and by adopting the Fresnel diffraction mode, the refractive index of the defect regions was determined to be lower than that of the apatite crystal. Present findings suggest that the interlayering structure along the (100) planes is responsible for the line defects observed in enamel apatites.
Elemental concentrations in air‐exposed and vacuum‐stored cryosections of rat liver cells
Authors: von Zglinicki T. , Zierold K. 
Published: August 2011

SUMMARYElemental concentrations in different compartments of cryosections of isolated rat liver cells cryotransferred and freeze‐dried were compared with those obtained after storage under vacuum for 12 or 60 h and after exposure to room air for 2 min. Poorer image contrast and segregation artefacts are frequently found in air‐exposed sections, together with a slight but significant decrease of the K concentration in the cytoplasm and an increase of the S concentration in the liver cell nuclei and the extracellular medium.Extreme distortions of both ultrastructure and elemental distributions are observed if the sections are even slightly colder than the surrounding atmosphere.While storage of frozen‐dried cryosections under vacuum for less than 12 h does not lead to alterations in the sections, gross changes are found both in morphology and elemental distribution in sections stored under vacuum for about 60 h. Long‐time vacuum storage of frozen‐dried cryosections is, therefore, not recommended.
Cryofixation of plant tissues without pretreatment
Authors: Kaeser Wulf , Koyro Hans‐Werner , Moor Hans 
Published: August 2011

SUMMARYRoot tips from Sorghum and Dahlia were frozen without cryoprotection by dipping into nitrogen slush, rapid immersion in liquid propane and by the high‐pressure method. Structural preservation of the samples was studied using freeze‐fracture (FF) and freeze‐substitution (FS) techniques for electron microscopy. It was found that most of the organelles were disrupted by freezing in nitrogen slush and that only the boundary beween the cytoplasm and the vacuole remained visible. If the samples were frozen by rapid immersion in liquid propane, small membraneous organelles, such as dictyosomes, were preserved in peripheral regions of the rhizodermal cells up to 10 μm below the surface of the tissue. Specimens frozen by the high‐pressure freezing technique showed good ultrastructural preservation throughout the tissues up to a depth of more than 100 μm.
The origins of the Royal Microscopical Society
Authors: Turner G. L'E. 
Published: August 2011

SUMMARYThe origin of the Microscopical Society of London on 3 September 1839 is explained in the context of the times. The new Society immediately had an effect on the standards of scientific microscopy by acquiring a library, a set of the finest microscopes, and by publishing papers. In 1866 a Royal Charter was granted under the Presidency of James Glaisher, FRS.
Applications of electron microscopy in materials science and technology (microscopy in the modern world)*
Authors: Ralph Brian 
Published: August 2011

SUMMARYA personal overview is presented attempting to show something of the broad range of applications of techniques associated with electron microscopy in the field of materials science and technology. The importance of electron microscopy in understanding microstructure/property relationships and the evolution of microstructure is stressed. In addition, some of the important uses of electron optical techniques in the more applied areas of materials technology are surveyed. The format adopted in this presentation is to illustrate the applications of electron microscopy in materials science and technology by citing recent studies. These include investigations of deformation, of grain growth, of precipitation and phase transformations and of the determination of the structure of interfaces.
Future trends in microscopy
Authors: Howie A. 
Published: August 2011

SUMMARYRecent progress and current trends in microscopy are examined with particular reference to possible future developments. The scope for systematic improvement of the traditional optical or electron designs and procedures seems far from exhausted. However the introduction of novel, lens‐free microscopes which, like the scanning tunnelling microscope, produce magnification using an electronic lever arm, could expand the boundaries of the subject most dramatically. The future microscopist may find himself displaced from the more routine tasks of focusing, alignment, image recording and even simple interpretation by the electronic robot. On the other hand, he will gain access to a wider and more sophisticated range of physical and chemical phenomena governing the interaction between the specimen and the radiations he uses to probe its microscopic structure and properties.
Determination of the coordination number in disordered packings of equal spheres
Authors: Oger L. , Lichtenberg M. , Gervois A. , Guyon E. 
Published: August 2011

SUMMARYA computation of the coordination number in a packing of equal spheres can be performed from the information obtained along a random line through the packing. It involves the distribution of the number per unit length of separators between intercepts of spheres with the line. The number of contacts per unit volume is derived from the slope of the distribution at the origin. The method is validated by computer experiments on four kinds of simulated ordered packings which are intercepted by a set of random lines (instead of a single one) in order to compensate biased results due to the small size of these packings: the comparison is then extended to a series of disordered dense packings of equal spheres. We present some possible applications of this study to stereological and physical problems.
An integrated PC‐based image analysis system for microtomography and quantitative analysis of inner micro‐object structure
Authors: Sasov A. Yu. 
Published: August 2011

SUMMARYA new type of image processing system, including microtomographic analysis, is presented. The great majority of existing approaches to image processing and analysis can be achieved by means of software, with a minimal amount of hardware. The addition of microtomographic methods to an image processing system allows quantitative parameters of inner object microstructure to be obtained non‐destructively.
Determination of gold‐labelled surface receptors on single cells by X‐ray microanalysis
Authors: Peschke Th. , Augsten K. , Sasama F. , Gabert A. 
Published: August 2011

SUMMARYA standardless X‐ray microanalytical procedure has been developed to determine the number of gold‐labelled surface receptors on whole single cells. The effect of the injection of K2PtCl4 into mice on gold‐labelled concanavalin A (Con A) receptors on peritoneal macrophages was examined with an energy dispersive X‐ray detector in an SEM. The numbers of gold particles seen in electron micrographs and estimated by fluorescence photometric measurements of fluorescein isothiocyanate‐labelled Con A receptors were correlated with the X‐ray microanalytical results.