6,170 research outputs found

    Suppression of myocardial fibrosis by valsartan and monopril in animals after acute myocardial infarction

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    Expression of Cyclooxygenase-2 Protein in Acute Myocardial Infarction

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    Nuclear forward scattering in particulate matter: dependence of lineshape on particle size distribution

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    In synchrotron Moessbauer spectroscopy, the nuclear exciton polariton manifests itself in the lineshape of the spectra of nuclear forward scattering (NFS) Fourier-transformed from time domain to frequency domain. This lineshape is generally described by the convolution of two intensity factors. One of them is Lorentzian related to free decay. We derived the expressions for the second factor related to Frenkel exciton polariton effects at propagation of synchrotron radiation in Moessbauer media. Parameters of this Frenkelian shape depend on the spatial configuration of Moessbauer media. In a layer of uniform thickness, this factor is found to be a simple hypergeometric function. Next, we consider the particles spread over a 2D surface or diluted in non-Moessbauer media to exclude an overlap of ray shadows by different particles. Deconvolving the purely polaritonic component of linewidths is suggested as a simple procedure sharpening the experimental NFS spectra in frequency domain. The lineshapes in these sharpened spectra are theoretically expressed via the parameters of the particle size distributions (PSD). Then, these parameters are determined through least-squares fitting of the line shapes.Comment: 13 pages, 12 figure

    Magnetically tunable properties related with carriers density in self-doped La1−xMnO3/y wt %Nb-SrTiO3 heteroepitaxial junctions

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    The self-doped La1−xMnO3 (x=0.1 and 0.3) thin films deposited on Nb-doped (wt % y) SrTiO3 (y=0.05 and 0.8) crystals to form heteroepitaxial junctions have been prepared by the pulse laser deposition method. The current-voltage loops of junction were measured at several fixed magnetic fields for the temperature from 10 to 300 K. We have focused on the effects of doping level and annealing time on the magnetically tunable property of the junction. The results show that these junctions have a typical temperature-dependent rectifying characteristics and asymmetrical hysteresis. The magnetically tunable property of the junction was related with the annealing time for the self-doped La1−xMnO3−δ thin film and the doping level in the Nb-doped SrTiO3 (STON) crystal. In the self-doped La0.9MnO3/0.05-STON junction annealed at 900 °C for 5 h, the relative ratio of voltage [Vb(0)−Vb(H)] /Vb(0) is about 70% at H=6 T and T=70 K for I=0.1 mA, showing a large magnetically tunable property. These results reveal the great potential of the manganites in configuring artificial devices.published_or_final_versio

    Effect of applied magnetic field on the rectifying characteristics in self-doped La0.9MnO3/0.8 wt %Nb-SrTiO3 heteroepitaxial junctions

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    The epitaxial self-doped La0.9MnO3 thin film was deposited on a 0.8 wt %Nb-doped SrTiO3 substrate by pulse laser deposition method to form a bilayer p-n junction with an area of 8 mm2. The isothermal current-voltage loops measured from 10 to 380 K with an interval of 10 K in applied magnetic fields up to 7 T show typical temperature-dependent rectifying characteristic and asymmetrical hysteresis. The effect of magnetic field on the rectifying property is very small for the temperature above 150 K and a strong asymmetrical effect on the rectifying property below 150 K. In the low temperature region, although the diffusive voltage Vd is not affected by the applied magnetic field, the breakdown voltage Vb decreases with the increasing of magnetic field. At 10 K, the relative ratio of voltage [Vb(0)−Vb(7 T)]/Vb(0) is about 14%, showing a magnetically tunable property. These results reveal the great potential of the manganites in configuring artificial devices.published_or_final_versio

    Absolute quantitation of DNA methylation of 28 candidate genes in prostate cancer using pyrosequencing

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    This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Aberrant DNA methylation plays a pivotal role in carcinogenesis and its mapping is likely to provide biomarkers for improved diagnostic and risk assessment in prostate cancer (PCa). We quantified and compared absolute methylation levels among 28 candidate genes in 48 PCa and 29 benign prostate hyperplasia (BPH) samples using the pyrosequencing (PSQ) method to identify genes with diagnostic and prognostic potential. RARB, HIN1, BCL2, GSTP1, CCND2, EGFR5, APC, RASSF1A, MDR1, NKX2-5, CDH13, DPYS, PTGS2, EDNRB, MAL, PDLIM4, HLAa, ESR1 and TIG1 were highly methylated in PCa compared to BPH (p < 0.001), while SERPINB5, CDH1, TWIST1, DAPK1, THRB, MCAM, SLIT2, CDKN2a and SFN were not. RARB methylation above 21% completely distinguished PCa from BPH. Separation based on methylation level of SFN, SLIT2 and SERPINB5 distinguished low and high Gleason score cancers, e.g. SFN and SERPINB5 together correctly classified 81% and 77% of high and low Gleason score cancers respectively. Several genes including CDH1 previously reported as methylation markers in PCa were not confirmed in our study. Increasing age was positively associated with gene methylation (p < 0.0001). Accurate quantitative measurement of gene methylation in PCa appears promising and further validation of genes like RARB, HIN1, BCL2, APC and GSTP1 is warranted for diagnostic potential and SFN, SLIT2 and SERPINB5 for prognostic potential

    Investigation of Non-Stable Processes in Close Binary Ry Scuti

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    We present results of reanalysis of old electrophotometric data of early type close binary system RY Scuti obtained at the Abastumani Astrophysical Observatory, Georgia, during 1972-1990 years and at the Maidanak Observatory, Uzbekistan, during 1979-1991 years. It is revealed non-stable processes in RY Sct from period to period, from month to month and from year to year. This variation consists from the hundredths up to the tenths of a magnitude. Furthermore, periodical changes in the system's light are displayed near the first maximum on timescales of a few years. That is of great interest with regard to some similar variations seen in luminous blue variable (LBV) stars. This also could be closely related to the question of why RY Sct ejected its nebula.Comment: 11 pages, 6 figures, 2 table

    Spin- and energy relaxation of hot electrons at GaAs surfaces

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    The mechanisms for spin relaxation in semiconductors are reviewed, and the mechanism prevalent in p-doped semiconductors, namely spin relaxation due to the electron-hole exchange interaction, is presented in some depth. It is shown that the solution of Boltzmann-type kinetic equations allows one to obtain quantitative results for spin relaxation in semiconductors that go beyond the original Bir-Aronov-Pikus relaxation-rate approximation. Experimental results using surface sensitive two-photon photoemission techniques show that the spin relaxation-time of electrons in p-doped GaAs at a semiconductor/metal surface is several times longer than the corresponding bulk spin relaxation-times. A theoretical explanation of these results in terms of the reduced density of holes in the band-bending region at the surface is presented.Comment: 33 pages, 12 figures; earlier submission replaced by corrected and expanded version; eps figures now included in the tex

    Detecting topological currents in graphene superlattices

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    This is the author accepted manuscript. The final version is available from AAAS via the DOI in this record.Topological materials may exhibit Hall-like currents flowing transversely to the applied electric field even in the absence of a magnetic field. In graphene superlattices, which have broken inversion symmetry, topological currents originating from graphene's two valleys are predicted to flow in opposite directions and combine to produce long-range charge neutral flow. We observed this effect as a nonlocal voltage at zero magnetic field in a narrow energy range near Dirac points at distances as large as several micrometers away from the nominal current path. Locally, topological currents are comparable in strength with the applied current, indicating large valley-Hall angles. The long-range character of topological currents and their transistor-like control by means of gate voltage can be exploited for information processing based on valley degrees of freedom.This work was supported by the European Research Council, the Royal Society, the National Science Foundation (STC Center for Integrated Quantum Materials, grant DMR‐1231319), Engineering & Physical Research Council (UK), the Office of Naval Research and the Air Force Office of Scientific Research

    Oxygen-regulated transcription factors and their role in pulmonary disease

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    The transcription factors nuclear factor interleukin-6 (NF-IL6), early growth response-1 (EGR-1) and hypoxia-inducible factor-1 (HIF-1) have important roles in the molecular pathophysiology of hypoxia-associated pulmonary disease. NF-IL6 controls the production of interleukin (IL)-6 in vascular endothelial cells, which may have anti-inflammatory activity by counteracting effects of IL-1 and IL-8. EGR-1 controls the production of tissue factor by macrophages, which triggers fibrin deposition in the pulmonary vasculature. HIF-1 activates the expression of the vasoconstrictor endothelin-1 in vascular endothelial cells. Angiotensin II induces HIF-1 expression and hypertrophy of pulmonary arterial smooth muscle cells. HIF-1 might therefore have multiple roles in the pathogenesis of pulmonary vascular remodeling
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