bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression analysis of putative stem cell markers in human benign and malignant prostate
Authors: Ugolkov Andrey V. , Eisengart Laurie J. , Luan Chunyan , Yang Ximing J. 
Published: June 2010

AbstractBACKGROUNDStem cells were suggested to be present in human prostate cancer as a small population of distinct cells, which may contribute to carcinogenesis, tumor recurrence, and chemoresistance. To identify potential prostatic stem cells, we analyzed the expression of several potential stem cell markers in benign prostate and prostatic adenocarcinoma.METHODSCD44, CD133, Oct4, SOX2, and EZH2 expression was detected by immunohistochemical (IHC) staining using tissue microarray assays (TMA) composed of benign (non‐neoplastic) prostatic tissue, high grade prostatic intraepithelial neoplasia (HGPIN), and prostatic adenocarcinoma. Positive staining was defined as 1+ (<10%), 2+ (10–50%), or 3+ (>50%).RESULTSWe found CD44 staining in 97% and 72% of benign + HGPIN and malignant lesions, respectively. CD133 staining was detected in a small fraction (4 of 67) of prostate carcinomas. We found that Oct4 nuclear expression was strongly associated with benign lesions and HGPIN but not prostate cancer (P < 0.05). In most cases, nuclear expression of EZH2 and SOX2 was detected in less than 10% of cells in non‐neoplastic prostate glands, HGPINs or prostate adenocarcinomas. Moreover, 27 of 33 SOX2 1+ prostate cancers were also EZH2 1+, whereas all 33 of these cases were CD44+.CONCLUSIONSExpression of CD44 and Oct4 identified large populations of benign and malignant cells in the prostate, which did not fit the definition of stem cells as a small fraction of the total cell population. Our results suggest that combined expression of embryonic stem cell markers EZH2 and SOX2 might identify potential cancer stem cells as a minor (<10%) subgroup in CD44+ prostatic adenocarcinoma. Prostate 71: 18–25, 2011. © 2010 Wiley‐Liss, Inc.
Serum Mac‐2BP does not distinguish men with high grade, large volume prostate cancer from men with benign prostatic hyperplasia
Authors: Peehl Donna M. , Chen Zuxiong , Nolley Rosalie 
Published: June 2010

AbstractBACKGROUNDMac‐2 binding protein (Mac‐2BP) is a secreted protein that has been used as a serum prognostic marker for several types of cancers. A previous study showed that serum Mac‐2BP was significantly higher (∼2‐fold) in men with prostate cancer compared to healthy men. We investigated whether serum Mac‐2BP could distinguish men with high grade, large volume prostate cancer from men with benign prostatic hyperplasia (BPH).METHODSA commercially available ELISA kit was used to measure Mac‐2BP in paired pre‐ and post‐prostatectomy sera from 10 men with high grade, large volume prostate cancer, in pre‐operative sera from 50 untreated men with high grade, large volume prostate cancer, and in sera from 50 men with clinical symptoms of BPH and biopsy‐negative for prostate cancer. Results were analyzed by Student's t‐test and receiver operating characteristic (ROC) curves.RESULTSLevels of Mac‐2BP did not decrease in post‐prostatectomy sera, and Mac‐2BP values were not significantly different in the sera of men with prostate cancer versus those with BPH.CONCLUSIONSerum Mac‐2BP does not appear to originate in the prostate and it is unlikely that Mac‐2BP can be used for the differential diagnosis of prostate cancer versus BPH. Prostate 71: 26–31, 2011. © 2010 Wiley‐Liss, Inc.
Homology modelling of Drosophila cytochrome P450 enzymes associated with insecticide resistance
Authors: Jones Robert T , Bakker Saskia E , Stone Deborah , Shuttleworth Sally N , Boundy Sam , McCart Caroline , Daborn Phillip J , ffrench‐Constant Richard H , van den Elsen Jean MH 
Published: June 2010

AbstractBACKGROUND: Overexpression of the cytochrome P450 gene Cyp6g1 confers resistance against DDT and a broad range of other insecticides in Drosophila melanogaster Meig. In the absence of crystal structures of CYP6G1 or complexes with its substrates, structural studies rely on homology modelling and ligand docking to understand P450–substrate interactions.RESULTS: Homology models are presented for CYP6G1, a P450 associated with resistance to DDT and neonicotinoids, and two other enzymes associated with insecticide resistance in D. melanogaster, CYP12D1 and CYP6A2. The models are based on a template of the X‐ray structure of the phylogenetically related human CYP3A4, which is known for its broad substrate specificity. The model of CYP6G1 has a much smaller active site cavity than the template. The cavity is also ‘V’‐shaped and is lined with hydrophobic residues, showing high shape and chemical complementarity with the molecular characteristics of DDT. Comparison of the DDT–CYP6G1 complex and a non‐resistant CYP6A2 homology model implies that tight‐fit recognition of this insecticide is important in CYP6G1. The active site can accommodate differently shaped substrates ranging from imidacloprid to malathion but not the pyrethroids permethrin and cyfluthrin.CONCLUSION: The CYP6G1, CYP12D1 and CYP6A2 homology models can provide a structural insight into insecticide resistance in flies overexpressing P450 enzymes with broad substrate specificities. Copyright © 2010 Society of Chemical Industry
Process of epitaxial crystal growth for CaSO4 · 0.5H2O on a surface of dissolving fluorapatite crystals studied by scanning electron microscopy
Authors: Dorozhkin S. V. 
Published: June 2010

AbstractA process for the epitaxial crystal growth for CaSO4· 0.5H2O on a surface of dissolving natural fluorapatite (FAP) crystals under conditions of wet‐process phosphoric acid production has been studied by scanning electron microscopy (SEM). With the SEM working in a secondary electron mode, we were able to establish the main stages of the coating formation, including direct measurements of its thickness and growing rate values for individual needle‐like CaSO4· 0.5H2O crystals. Confirmation of an aggregate mechanism for CaSO4· 0.5H2O epitaxial crystals growth, established earlier under conditions of chemical crystallization, was achieved for the first time. The mechanism includes the following steps: (1) ultramicrocrystals of CaSO4· 0.5H2O were formed, (2) they coalesced into needle‐like crystals by means of mutual aggregation, (3) the needle‐like crystals united into star‐like and besom‐like aggregates, and (4) the latter formed macro‐aggregates. We have found that these steps occur simultaneously, resulting in multilayer coating formation. During the investigation, the phenomenon of FAP crystals aggregation by means of mutual intergrowing of epitaxial CaSO4· 0.5H2O coatings and the peculiarities of the etching process for the FAP crystal surface under conditions of CaSO4· 0.5H2O coatings formation were also studied.
Observation of the retina using the tandem scanning confocal microscope
Authors: Mathers William , Littlefield Timothy , Lakes Roderic , Lane James A. , Daley Thomas E. 
Published: June 2010

AbstractA tandem scanning confocal microscope (TSCM) is currently being used to obtain high‐resolution images of the human cornea in vivo. Advantages of confocal microscopy for in vivo imaging include optical sectioning and increased contrast through removal of scattered light. We have adapted the TSCM to view the retina in vivo by constructing an applanating lens and fitting the microscope with an imaging‐intensifying camera of increased sensitivity. The microscope uses a spinning disc with 40,000 holes, each of 30 microns diameter, and a 100 W mercury arc lamp light source with a 455 nm long pass filter. The applanating lens is composed of three elements, two of which are movable for focusing. Images of a rabbit retina were obtained in vivo revealing the nerve fiber layer and blood vessels around the optic disc. The power density at the retina was calculated to be 3 mW/cm2, which is well below the power levels of a direct or indirect ophthalmoscope. Magnification of the retinal image was approximately 60x and a 1 mm wide area of retina was in view. This prototype TSCM system demonstrates that images of a retina in vivo are obtainable with confocal microscopy and that the sharpness is comparable to standard fundus camera photography. Further modifications to improve the light level and alterations in the design of the objective should improve the quality of the images obtained and achieve the enhanced resolution of which, in theory, the confocal microscope is capable.
The mechanisms of formation of ohmic contacts to AlGaAs: A microstructural, elemental diffusion and electrical investigation
Authors: Cole M. W. , Han W. Y. , Casas L. M. , Eckart D. W. , Monahan T. , Jones K. A. 
Published: June 2010

AbstractInterfacial microstructure and phase composition of PtTiGePd ohmic contacts to heavily C‐doped AlGaAs were investigated as a function of annealing temperatures. Results of the material analyses were used to explain the specific contact resistances measured for each thermal treatment. Evidence of interdiffusion and compound formation between AlGaAs and Pd was visible in a Ga‐rich Pd‐Ga‐As reaction zone prior to heat treatment. As the annealing temperature was raised from 530 to 600°C, As began to out‐diffuse. At 600°C, this As out‐diffusion, which is critical to the formation of good p‐type ohmic contacts, contributed to the creation and development of the laterally continous two‐phase interfacial region, TiAs/Pd12Ga2Ge5, overlying the AlGaAs substrate. The minimum specific contact resistance was also achieved at this temperature. As the annealing temperature was elevated to 650°C, the specific contact resistance degraded in response to intensive chemical diffusion and development of a broad, nonuniform multiphased interfacial region.
Multiphase analysis of Bi‐Sr‐Ca‐Cu‐O high Tc superconductors with x‐ray compositional mapping
Authors: Marinenko R. B. , Bright D. S. , Bernik S. 
Published: June 2010

AbstractBa‐Sr‐Ca‐Cu‐O (BSCCO) high Tc superconductor specimens were prepared as part of a solid‐solubility study in the region of the 2223 phase. The identification and determination of the amount of each phase in the final products were necessary. Quantitative digital x‐ray compositional mapping with the electron microprobe was done with five wavelength spectrometers, one for each of the cations. To facilitate phase identification and quantification, image processing rules were developed for the nine possible phases, with each assigned a unique color. Using this procedure, at least six different phases were identified. Examples are cited in color.
Angular‐dependent energy distributions for backscattered electrons—Calculation of the surface ionization
Authors: Andrae M. , Rührbacher K. , Klein P. , Rnisch J. W. 
Published: June 2010

AbstractAn equation for angular‐dependent energy distributions of backscattered electrons is presented. Extensive Monte Carlo simulations lead to a simple description for the energy distribution. A comparison of the new expression with experimentally derived curves, Monte Carlo results, and an analytical model is performed. The newly derived energy distributions are used for the calculation of the surface ionization ϕ0 for oblique angle of incidence. For normal incidence, a comparison with several published experimental data leads to a mean value for the deviation of < 4%. For tilted specimens the results are compared with findings of other authors.
New expressions for angular distributions
Authors: Klein P. , Andrae M. , Röhrbacher K. , Wernisch J. 
Published: June 2010

AbstractAn electron scattering model (multiple reflections) based on physical quantities only is refined and extended. New expressions for the most probable scattering angle, for the angular distribution of transmitted electrons, and for the angular distribution of backscattered electrons under oblique incidence, derived by fitting to already published data or to Monte Carlo results, are presented and compared with well‐established formulae. The mean path‐elongation factor for a multiple reflection model is calculated by introducing a correlation of angular distributions. The value of the new path elongation factor is compared with already existing fits.
A computer program to illustrate macro topography on electron backscattering
Authors: Howell P. G. T. 
Published: June 2010

AbstractThis paper describes a computer program which enables the trajectories of an electron to be followed inside a solid sample and its pathway if it is successful to exit the sample's surface, and to be considered a backscattered electron (BSE). The simulation aids to understand the backscattering process and the effect of the sample that has other than an ideal flat surface topography. Several types of surface for the sample are simulated: a flat surface which can be tilted, a rough surface represented by a sine wave, and a circular surface to represent filamentous structures. The target material is entered as its empirical formula so that its mean atomic number may be calculated. It is covered with a layer of conductive coating, and it may be structured with vertical or horizontal layers of a second‐phase material. Where appropriate, the position of the electron beam impacting on the target may be moved in relation to the underlying structures. The passage of the electron through the substrate is displayed on the computer monitor in high‐resolution graphics. Information about those electrons which return to the sample surface and are backscattered is stored for later analysis. The paths of these BSEs are replotted to show the volume of the sample from which the image‐forming data are derived. Further graphic output provides histograms of the energy distribution and of the BSEs exit direction.
Vascular regression during amphibian metamorphosis—A scanning electron microscope study of vascular corrosion casts of the ventral velum in tadpoles of Xenopus laevis Daudin
Authors: Aichhorn Heidi , Lametschwandtner Alois 
Published: June 2010

AbstractWe used scanning electron microscopy and vascular casting to study gross arterial supply, venous drainage, and microvascular patterns of the fully developed ventral velum of tadpoles of Xenopus laevis Daudin and analyzed changes of the velar vascular bed from prometamorphosis to metamorphic climax in a qualitative and quantitative manner. The multilayered, highly secretory ventral velum is supplied bilaterally by an anterior and a posterior velar artery, branches of the external carotid artery. Velar arterioles branch mainly dichotomously and form a flat two‐dimensional capillary meshwork overlying the tops of filterplates I‐IV. Thymopharyngeal veins, dorsal branches of the filter plates veins, and the internal jugular veins drain the velum toward the venous sinus of the heart. Location, architecture, and the drainage of the velar microvascular bed into the venous sinus make a significant contribution of the velar capillaries to gas exchange unlikely. Instead, velar capillaries rather serve the nutrition of the secretory epithelium. The overall morphology of velar vessels from prometamorphosis to metamorphic climax—deduced from vascular corrosion casts—points to atonic vessels with increased leakage indicated by adhering globular extravasations, and to obstructed or blind ending vessels evidenced by the tapered and/or rounded blind ending cast vessels. The significant decrease in the size of the ventral velum during the metamorphic cycle was paralleled by a miniaturization of the velar vascular bed. We hypothetize that this miniaturization occurs by a shortening and fusion of capillary mesh elements. Our findings in corrosion casts, particularly the miniaturization of the velar microvascular bed and the morphology of the regressing capillaries, point to profound morphologic and ultrastructural changes in velar vessels; a study on the fine structure of the microvascular bed of the ventral velum in metamorphic tadpoles is in progress.
Imaging deep holes in structures with gaseous secondary electron detection in the environmental scanning electron microscope
Authors: Newbury Dale E. 
Published: June 2010

AbstractThe gaseous secondary electron detector (GSED) in the environmental scanning electron microscope (ESEM) permits collection of electron signals from deep inside blind holes in both conducting and insulating materials. The placement of the GSED as the final pressure‐limiting aperture of the ESEM creates a situation of apparent illumination along the line of sight of the observer. In principle, any point struck by the primary beam can be imaged. Image quality depends on the depth of the hole. In brass, features at the bottom of a 1.5 mm diameter hole that was 8 mm deep were successfully imaged.
A new method for low‐magnification in the environmental scanning electron microscope
Authors: Taylor M. E. , Wight S. A. 
Published: June 2010

AbstractA device has been developed and used successfully on two models of the environmental scanning electron microscope that allows low‐magnification imaging of about 30x, significantly better than the original 200x low‐magnification imaging limit. This was achieved by using an additional aperture to limit the pressure at a point where it will not block the electron beam, and a larger aperture plate for the combination final aperture/secondary electron signal collection surface that also does not block the electron beam significantly.
Environmental scanning electron microscope observations of H2S attack on the protective oxide on an Ni‐Fe alloy
Authors: Pirttiaho Lauuri , Blakely Jack 
Published: June 2010

AbstractProtective oxide layers on metals are frequently attacked by corroding agents. In this study, the attack of H2S on the protective oxide on 60 wt‐%Ni‐40 wt‐%Fe was studied. The oxide layer was prepared in a UHV system and the sulphidation was done in an environmental scanning electron microscope at an elevated temperature. The single crystal Ni‐Fe sample had a (100) surface which was oxidized by O2 exposure at about 800 K to produce an epitaxial Fe2O3 film. The breakup of the oxide was found to begin by pitting along surface features which are believed to correspond to atomic steps or step bunches. The areas where the oxide was more uniform were found to show better resistance toward the sulphidation.
Investigation of cholesterol, bilirubin, and protein distribution in human gallstones by color cathodoluminescence scanning electron microscopy and transmission electron microscopy
Authors: Loginov A. S. , Chebanov S. M. , Petrakov A. V. , Saparin G. V. , Obyden S. K. , Ivannikov P. V. 
Published: June 2010

AbstractThe application of color cathodoluminescent scanning electron microscopy (CCL‐SEM) for qualitative luminescence analysis of cholesterol, bilirubin, and protein in human gallstones was demonstrated. Images of these deposits (cholesterol, bilirubin, and protein) were formed in real colors (blue—cholesterol, red, orange—bilirubin, yellow, green—protein) in accordance with the cathodoluminescent spectrum for each control material. The other method described for transmission electron microscopy (TEM) of ultra‐thin sections provides more detailed characterization of the ultrastructure of cholesterol‐containing regions and their spatial interrelations with bilirubin‐containing regions. Using CCL‐SEM combined with TEM permits the receipt of more complete information about the chemical composition and ultrastructure of gallstones and may lead to more effective understanding of the pathogenesis of cholesterol cholelithiasis.
Changes in the microstructural and electrical behavior of poly‐Si films subjected to ion implantation and annealing process modifications
Authors: Cole M. W. 
Published: June 2010

AbstractPolycrystalline silicon (poly‐Si) films implanted with arsenic using beam currents of 500 μA (400°C) and 230 μA (room temperature) have been investigated via transmission electron microscopy (TEM), secondary ion mass spectrometry (SIMS), and spreading resistance analysis (SRA). Experimental observations demonstrated the annealed high beam current‐implanted poly‐Si to possess inferior electrical properties compared with that implanted at a lower beam current. The reduced electrical activity of the high beam current‐versus the low beam current‐implanted poly‐Si was directly related to the postimplant microstructure (small grains ∼140 nmvs. amorphous) and the mechanism of the subsequent anneal (grain growth vs. recrystallization). The recrystallization mechanism augmented the electrical activation of the As dopant (decreased sheet resistivity) via a reduction of total grain boundary area. Further improvement in the electrical performance of the low beam current‐implanted poly‐Si, a resistivity decrease of up to 28%, was incurred via a two‐step annealing process. This process induced grain growth, which in turn minimized total grain boundary area and dopant trapping.
Monte Carlo simulation of electron backscattering from compounds with low mean atomic number
Authors: Howell P. G. T. , Boyde A. 
Published: June 2010

AbstractThis paper reports a Monte Carlo simulation where a single atom scattering model is adopted. The element taking part in each electron‐atom interaction is selected on the basis of its contribution eitherto the total elastic cross section or to the electron's mean free path. Both Rutherford and Mott scattering are considered, with the continuous slowing down process of Bethe used to calculate the energy loss to the system. The backscattered electron coefficients show good agreement with experimental results from a large group of low atomic number materials when using a model which selects the scattering atom by its contribution to the whole compound calculated from its atomic fraction of the total elastic cross‐section.
Particle development in apple juice determined by light scattering and electron microscopy
Authors: Beveridge T. , Harrison J. H. , Dalgleish D. G. 
Published: June 2010

AbstractLight scattering was used to detect the kinetic development of particles in apple juices produced with and without oxidation and in procyanidin extracts prepared from these two juices. Particle size developed exponentially inboth oxidized and unoxidized juices, suggesting an enzymatic origin for the particle forming reactions. The procyanidin extract from oxidized juices produced particles which grew linearly, suggesting diffusion‐controlled aggregation or coalescence of particles. Procyanidins from unoxidized juice showed no particle development over at least 60 days of storage. Electron microscopy showed particles similar to those seen previously and some newly described morphologies. The mechanism of haze particle development is discussed in the light of the light scattering and electron microscopic results.
Reproducibility and accuracy of spatial measurements from digitally captured images in the environmental scanning electron microscope
Authors: Cousens D. R. , Kinaev N. N. , Ranasinghe M. 
Published: June 2010

AbstractAccurate spatial measurements in a scanning electron microscope (SEM) require calibration of the magnification as a function of working distance and microscope operating conditions. This work presents the results of the calibration of an environmental SEM for the accurate spatial measurement of dimensions and areas in experiments, both for the measurement of strain in steel specimens under applied loads and the measurement of dimensional changes in timber with changes in relative humidity.