bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optically active centers in diamond as‐grown at temperatures 1200–1350°C
Authors: Ekimov E. A. , Klimin S. A. , Borovikov H. F. , Saparin G. V. , Obyden S. K. , Rulev G. B. 
Published: June 2010

AbstractDiamonds were grown in the vicinity of the “diamond‐graphite” equilibrium state by the spontaneous crystallization method to study the creation of defects and crystalline imperfections. Crystals were synthesized in the graphite‐Ni‐Mn system. Raman and luminescence spectroscopy, electron microscopy, and optical absorption spectroscopy were used for diamond crystal inspection. Diamonds were classified into three groups: (1) black, nontransparent, curved, flat‐faced crystals; (2) dark or black semitransparent crystals of cubic habit with faceting of the cube vertices by (111) planes; (3) amber‐yellow crystals showing a cubic‐octahedral habit.The yellow crystals revealed the infrared (IR) absorption spectra within the range of 800–4000 cm‐1 that are peculiar for diamonds of the 1a group. IR spectra displayed a number of additional absorption peaks for black semitransparent crystals. A marked peak at 2835 cm‐1 and a less pronounced peak at 2919 cm‐1 unambiguously demonstrate the presence of hydrogen. An intensive absorption in the range of 800–1100 cm‐1 with a maximum at 969 cm‐1 may be explained by both the presence of hydrogen and extended defects, taking into account the data arrived at by cathodoluminescence, emission spectra, and Raman spectroscopy. For the first time, the narrow peak at 1332 cm‐1, unknown for mined diamonds and observed in flame‐chemical vapor deposition (FL‐CVD) diamond films, was revealed in diamonds synthesized under high pressure.The presence of peaks with maximum at 2919, 1252, and 1332 cm‐1 in the IR spectra of the black diamonds and FL‐CVD diamond films indicated a certain similarity in diamond formation for high‐ pressure and vapor deposition techniques and an important role of hydrogen in high‐pressure diamond growth. The source of hydrogen is probably graphite used in the synthesis. The increase in diamond synthesis temperature decreases the probability of hydrogen capture and provides a better crystal quality. Cathodoluminescence scanning electron microscopy demonstrated the spatial distribution of luminescence centers on different diamond crystal faces. Some crystal fragments emit A‐band (420–460 nm) and have well‐faceted faces that confirm their high perfection and quality that are close to natural diamonds.
A multiple technical approach to the study of apoptotic cell micronuclei
Authors: Columbaro M. , Gobbi P. , Renò F. , Luchetti F. , Santi S. , Valmori A. , Falcieri E. 
Published: June 2010

AbstractApoptotic micronuclei have been studied, in different cell types, from a morphologic and functional point of view. Conventional electron microscopy, in various staining conditions, selective cytochemistry for DNA, and freeze fracture for the analysis of chromatin fiber organization and size were performed. In situ TdT and Pol I immunofluorescent techniques were carried out to detect double‐ and single‐strand DNA breaking points by confocal laser scanning microscopy. Apoptotic cell ultrathin cryosections were also performed and were analysed by field emission in lens scanning electron microscopy. Double/single strand massively cleaved DNA was detected in micronuclei, with a highly supercoiled, uniformly packed, very dense arrangement.
Morphologic and temporal analysis of vascular smooth muscle cell apoptosis induced by c‐Myc and E1A
Authors: Allen R. Todd , Hunter William J. , Agrawal Devendra K. 
Published: June 2010

AbstractApoptosis is a physiologic form of cell death present in many disease conditions. When the balance of mitosis versus apoptosis is altered, tumor‐like growth or degeneration of tissues may ensue. This appears to occur in several diseases, including those of the cardiovascular system, where apoptosis plays a key role in atherosclerosis and restenosis following angioplasty. Since c‐myc is upregulated in the pathogenesis of these diseases, we chose to study the sequential morphologic features of programmed cell death in vascular smooth muscle cells induced by c‐myc and by the adenovirus early gene E1A. Morphology and timed events in apoptotic cell cultures were analyzed by scanning electron microscopy, transmission electron microscopy, and time‐lapse videomicroscopy. We observed that both c‐myc‐and E1A‐induced apoptosis (in serum‐free medium) resulted in numerous, tightly packed clusters of apoptotic blebs, as well as in one or two asymmetrically larger blebs. Transmission electron microscopy analysis revealed the larger blebs contained mostly nuclear chromatin, whereas the many smaller fragments often had little or no chromatin. Time‐lapse studies showed that apoptosis was induced at a slower rate in cells stably transfected with c‐myc versus those stably transfected with E1A. The early changes of apoptosis, including cell shrinkage and intense blebbing, occurred in under 5 min in both cells. Slight alterations such as cell size and further rounding occurred up to 8 h following the initial changes of apoptosis. Rather than being a part of the apoptotic response, release from the culture floor almost entirely resulted from movement of the culture flask. These studies provide a framework of timed morphologic events for future mechanistic investigation into the key aspects of myc‐and E1A‐induced apoptosis in vascular smooth muscle.
Elemental and molecular imaging of human hair using secondary ion mass spectrometry
Authors: Gillen Greg , Roberson Sonya , Ng Connie , Stranick Michael 
Published: June 2010

AbstractSecondary ion mass spectrometry (SIMS) is used to image the spatial distribution of elemental and molecular species on the surface and in cross sections of doped human hair using a magnetic sector SIMS instrument operated as an ion microprobe. Analysis of electrically insulating, non‐planar hair samples requires one of two different methods of charge compensation to be used depending on the polarity of the sputtered secondary ions. For detection of positive secondary ions, the hair is imaged using a ∼0.5 μm diameter, 19.5 keV impact energy, O− microbeam with no auxiliary electron bombardment. For detection of negative secondary ions, a ∼ 0.2 μm diameter, 14.5 keV impact energy Cs+ microbeam is used in conjunction with normal incidence, low‐energy electron bombardment. Both of these methods allow submicrometer spatial resolution elemental and molecular secondary ion images to be obtained from hair samples without metallic coating of the sample surface prior to analysis. Several examples are presented that reflect potential application areas for these analytical methods.
Complete angular distribution of electrons backscattered from tilted multicomponent specimens
Authors: Berger D. , Niedrig H. 
Published: June 2010

AbstractThis paper reports on the possibilities of predicting the angular distribution of electron backscattering from multicomponent specimens by use of a mean atomic number which is derived from the atomic or mass concentrations of the elements. It is found that Büchner's model using a quadratic weighed average of the atomic numbers is suitable although it is only based on single scattering.
Microstructural changes in zein proteins during extrusion
Authors: Batterman‐Azcona Sheri J. , Lawton John W. , Hamaker Bruce R. 
Published: June 2010

AbstractChanges in proteins during extrusion may influence the texture of ready‐to‐eat (RTE) corn‐based extruded foods. This study focused on microstructural changes and dispersal patterns of corn storage proteins, zeins, that occur during extrusion processing. Model systems were used that consisted of two types of corn protein: commercial zein and corn gluten meal (CGM), combined with corn starch. Commercial zein is not encased in protein bodies, whereas CGM is comprised of zeins encapsulated in protein bodies. Mixtures were extruded under conditions that resulted in different specific mechanical energy (SME). The microstructure of the resulting extrudates was analyzed using transmission electron microscopy (TEM) with immunogold labeling of the α‐zein storage protein. The micrographs showed that the greatest zein dispersal occurred in CGM/starch extrudates, especially under high SME conditions. The micrographs also showed that, at both mild and harsh extrusion conditions, commercial zein/starch extrudates contained large protein aggregates. Under mild extrusion conditions, protein bodies in the CGM/starch extrudates partially retained their spherical shapes, but during harsher processing, protein bodies were disrupted and dispersed zein appeared to form fibrils. Such protein fibrils may influence texture and/or quality of extruded corn‐based snacks and breakfast foods.
Nanoscale optical imaging of chromosomes with apertureless microscopy
Authors: Bridger P. M. , McGill T. C. 
Published: June 2010

AbstractNear‐field optical structure of the centromere region of undyed polytene chromosomes has been observed using an apertureless near‐field optical microscope that detects the intensity of light scattered from an atomic force microscope tip under laser illumination. The centromere is of primary importance to the functioning of the chromosome in the cell during cell division. It is also particularly interesting for structural/optical studies since its DNA repeat sequences are highly conserved among organisms and it is possible that they play a part in the centromere self assembly (Clark and Wall 1996).
The effect of fast secondary electrons on X‐ray microanalysis in the scanning electron microscope
Authors: Gauvin Raynald , Hovington Pierre , Drouin Dominique 
Published: June 2010

AbstractIn this paper, the effect of fast secondary electrons (FSE), which result from inelastic scattering of incident electrons, on the characterization of materials in the scanning electron microscope are investigated with the aid of Monte Carlo simulations. The effect of FSE on x‐ray microanalysis of light elements is investigated. A full description of the Monte Carlo simulations of FSE in solids is given.
Image sharpness measurement in the scanning electron microscope—Part III
Authors: Zhang Nien Fan , Postek Michael T. , Larrabee Robert D. , Vladár András E. , Keery William J. , Jones Samuel N. 
Published: June 2010

AbstractFully automated or semi‐automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an important aspect of quality control. The application of Fourier analysis techniques to the analysis of SEM images is a useful methodology for sharpness measurement. In this paper, a statistical measure known as the multivariate kurtosis is proposed as an additional useful measure of the sharpness of SEM images. Kurtosis is designed to be a measure of the degree of departure of a probability distribution. For selected SEM images, the two‐dimensional spatial Fourier transforms were computed. Then the bivariate kurtosis of this Fourier transform was calculated as though it were a probability distribution. Kurtosis has the distinct advantage that it is a parametric (i.e., a dimensionless) measure and is sensitive to the presence of the high spatial frequencies necessary for acceptable levels of image sharpness. The applications of this method to SEM metrology will be discussed.
A scanning and transmission electron microscopy study of the parabronchial unit in quail (Coturnix coturnix) and town pigeons (Columba livia)
Authors: Klika E. , Scheuermann D. W. , de Groodt‐Lasseel M. H. A. , Bazantova I. , Switka A. 
Published: June 2010

AbstractA combined scanning electron (SEM) and transmission electron microscopy (TEM) investigation was undertaken to gain insight into the complex structural pattern of the atrial compartment and the gas exchange tissue of parabronchial units in quail and town pigeons. The aim was also to depict the changes taking place in the parabronchial unit in the late prehatching and early posthatching periods in quail. The standard SEM and TEM investigation was carried out in 13 mature quail and 8 town pigeons. The developmental study involved embryonic quail (Days 15, 16, 17), newly hatched quail, quail 24 h after hatching, and quail aged 2, 10, 19, and 25 days (3 individuals per group). The luminal relief of the parabronchus is formed by anastomosing interatrial septa delineating the atrial pits, which are thinner and shallower in pigeons. The atrial bottom opens in mature individuals into 3–6 infundibula. The extracellular material represented by trilaminar substance, which does not appear until hatching, veils the surface relief of the parabronchial epithelium, which is consequently hardly accessible to three‐dimensional visualization. Only in town pigeons with fewer discontinuous layers of extracellular material was it possible to visualize the surface of the atrial epithelium, that is, of the granular and squamous atrial cells. The SEM analysis has convincingly shown the intricate spatial organization of atria, infundibula, and air and blood capillaries of the gas exchange tissue. The retinacula, that is, parallelly arranged processes of squamous respiratory cells bridging the air‐capillary lumina, were evidenced by SEM and TEM. The complex structure of the avian parabronchus has been successfully demonstrated in the present SEM and TEM study.
Scanning probe microscopy studies of cereal seed storage protein structures
Authors: Tatham Arthur S. , Thomson Neil H. , McMaster Terence J. , Humphris Andrew D. L. , Miles Mervyn J. , Shewry Peter R. 
Published: June 2010

AbstractScanning probe microscopes (SPMs) share a number of common features which give the techniques advantages over conventional light and electron microscopy. First, high resolution, up to the atomic level, is possible in certain cases, and second, they are nondestructive, requiring no staining or coating and the images can be obtained in the hydrated state or under water. Scanning probe microscopes, particularly scanning tunnelling microscopes (STM) and atomic force microscopes (AFM), have been used to study food‐related systems, ranging from relatively large structures such as starch granules to the organisation of secondary structures in proteins and the interaction of proteins. The seed storage proteins (gluten) of wheat are responsible for the viscous and elastic properties of wheat doughs that allow them to be used for a wide range of different food products. Using AFM and STM, images of individual and groups of proteins have been obtained in both the dry and hydrated states. The ability to work in liquid environments allows the conformation of proteins to be determined under conditions approaching “native.” The AFM and STM have been used to image both gliadins and glutenins and to study their aggregative behaviour in relation to gluten and dough systems.
Dynamic confocal scanning laser microscopy methods for studying milk protein gelation and cheese melting
Authors: Auty M. A. E. , Fenelon M. A. , Guinee T. P. , Mullins C. , Mulvihill D. M. 
Published: June 2010

AbstractDynamic confocal scanning laser microscopy (CSLM) methods were developed to enable observation of milk protein gelation and cheese melting. Protein aggregation and the formation of gel networks in renneted full‐fat and low‐fat milks and glucono‐δ‐lactone (GDL)‐acidified skim milks were observed by CSLM and observations correlated with increases in shear modulus (G′) and dynamic viscosity (η*) as determined by dynamic amplitude oscillatory rheology. Confocal scanning laser microscopy observation of low‐fat and full‐fat cheeses showed changes in fat distribution and an increase in staining intensity during cheese melting.
Microstructure of whole milk powder and of insolubles detected by powder functional testing
Authors: McKenna A. B. , Lloyd R. J. , Munro P. A. , Singh H. 
Published: June 2010

AbstractThe functional properties of whole milk powder (performance during reconstitution in water and coffee) are routinely measured to determine powder quality. An examination of the microstructure of milk powder and of the insoluble material collected after applying a series of functional tests provided insight into why the insoluble material formed during reconstitution.The microstructures (transmission electron microscopy and confocal microscopy) of four commercial whole milk powder samples and of the insoluble material produced during functional testing were assessed. The microstructure of the whole milk powder could be related to features observed in the microstructure of some of the insolubles collected after powder functional testing. It is likely that heating conditions throughout the powder manufacturing process resulted in the denaturation of β‐lactoglobulin and its interaction with other proteins and fat globule membrane components, thus influencing the solubility of the milk powder. The application of shear during processing resulted in the greatest change to powder solubility in this study. Increasing homogenisation pressure during processing resulted in fat globule size reduction, adsorption of casein micelles to the fat globule membrane, and the formation of clusters of fat globules caused by the sharing of adsorbed casein micelles. The presence of large numbers of these clusters in the milk powder increased the formation of insoluble material during powder reconstitution in water and coffee.
The effect of freezing method and frozen storage conditions on the microstructure of wild blueberries as observed by cold‐stage scanning electron microscopy
Authors: Allan‐Wojtas P. , Goff H. D. , Stark R. , Carbyn S. 
Published: June 2010

AbstractMicrostructural information about fresh fruit is difficult to obtain using standard electron microscopy methods. Frozen fruit presents additional temperature‐related challenges. However, the food industry would benefit from data that show structure/function relationships in fruit and changes that occur during freezing and frozen storage.The feasibility of using cold stage scanning electron microscopy (cryo‐SEM) to describe and define the structure/function relationships of quality attributes of frozen wild blueberries was tested. Cryo‐SEM was used to evaluate the structure of wild blueberries that had been frozen using three different methods, stored at three different temperatures, and held in frozen storage for 5 months. Micro‐structural data were then compared with quality measures, which included changes in percentage drip, damaged berries, and anthocyanin leakage, to explore relationships between structural changes and observed quality changes.Cryo‐SEM results indicated that microstructural changes observed in frozen blueberry samples are characteristic of their temperature history. Quality measurements and microstructural data are in agreement that improvement of frozen blueberry quality resulted from faster freezing rates and lower temperatures of storage than are used presently in standard production methods. This study indicates that cryo‐SEM can be a valuable tool in assessing frozen blueberry quality and developing optimal conditions for freezing wild blueberries.
Treatment of anionic emulsion systems using chitosan, polyacrylamide, and aluminum sulfate
Authors: Pinotti A. , Bevilacqua A. , Zaritzky N. 
Published: June 2010

AbstractThe presence of emulsified oil in waste water of the edible fats industry can interfere with many tertiary or advanced waste water treatments such as adsorption, filtration, and various membrane techniques, and can cause severe problems in the step of biological treatment. The objective of the present work was to compare the performance of three destabilizers: chitosan, polyacrylamide, and aluminum sulfate to flocculate an O/W emulsion formulated with different emulsifiers (sodium dodecyl sulfate and sodium tetradecyl sulfate). Experiments were performed on a model system constituted by sunflower oil/ water emulsions. Methods used were turbidimetry, colloidal titration, and microscopic observation. Results showed that the increase of surfactant chain length increases the destabilizer dose necessary to produce desta‐bilization and reaching zero charge. In chitosan and polyacrylamide treatments, redispersion was observed for both sodium dodecyl sulfate and sodium tetradecyl sulfate emulsions. In the case of treatment with aluminum sulfate, turbidity values remained nearly constant, showing that redispersion does not take place in this case.
Influence of topography and specimen preparation on backscattered electron images of bone
Authors: Vajda Eric G. , Humphrey Scott , Skedros John G. , Bloebaum Roy D. 
Published: June 2010

AbstractBackscattered electron (BSE) images of bone exhibit graylevel contrast between adjacent lamellae. Mathematical models suggest that interlamellar contrast in BSE images is an artifact due to topographic irregularities. However, little experimental evidence has been published to support these models, and it is not clear whether submicron topographical features will alter BSE graylevels. The goal of this study was to determine the effects of topography on BSE image mean graylevels and graylevel histogram widths using conventional specimen preparation techniques. White‐light interferometry and quantitative BSE imaging were used to investigate the relationship between the BSE signal and specimen roughness. Backscattered electron image graylevel histogram widths correlated highly with surface roughness in rough preparations of homogeneous materials. The relationship between BSE histogram width and surface roughness was specimen dependent. Specimen topography coincided with the lamellar patterns within the bone tissue. Diamond micromilling reduced average surface roughness when compared with manual polishing techniques but did not significantly affect BSE graylevel histogram width. The study suggests that topography is a confounding factor in quantitative BSE analysis of bone. However, there is little quantitative difference between low‐to‐moderate magnification BSE images of bone specimens prepared by conventional polishing or diamond micromilling.
Some theoretical considerations on X‐ray microanalysis in the environmental or variable pressure scanning electron microscope
Authors: Gauvin Raynald 
Published: June 2010

AbstractThis paper presents a new correction procedure for quantitative x‐ray microanalysis in the environmental or variable pressure scanning electron microscope (SEM). This method is based on a plot of the measured intensity as a function of the fraction of nonscattered beam intensity, fp. The theory predicts that the plot should be linear and the corrected intensity is given for fp = 1. The advantage is that such a plot is valid for any measured pressures, which is not the case with the usual pressure correction methods. To use this method, a simple equation is derived to compute fp. Other variations of this correction procedure are also presented. Comparison with measurements performed by Mansfield (1999) show the great consistency of this method.
The interaction of biological molecules with clay minerals: A scanning force microscopy study
Authors: Porter T. L. , Eastman M. P. , Whitehorse R. , Bain E. , Manygoats K. 
Published: June 2010

AbstractWe have used the technique of scanning force microscopy (SFM) to investigate the reaction of both amino acids and activated nucleotides in the presence of the clay mineral Cu(II)‐exchanged hectorite. Using simulated prebiotic heating and wetting cycles, we have shown that the clay mineral acts to adsorb, concentrate, and subsequently catalyze the polymerization of these biological monomers into short peptides and oligonucleotides. The presence of the Cu(II) cations within the clay intergallery regions, and at surface step edges and cracks, is crucial for the observed reactions to occur. Clay minerals such as hectorite may have thus played an important role in the evolution of biologically viable molecules on the prebiotic earth.