481 research outputs found

    (V_1-_XCr_X)_2O_3(x<=0.03)におけるRamanæ•Łäč±ăšé‡‘汞 : ç”¶çžäœ“è»ąç§»

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    Metal-Insulator transition in (V__Cr_x)_2o_3(x≩O.03) has been studied by Raman scattering. The 1.5 % Cr-substituted V_2O_3 showed the high temperature insulator (I-phase) metal (M-phase) transition, without cyrstallographic change at 223K, where the Raman spectra also changed drastically. The spectra of M-phase are similar to those of pure V_2O_3 with regard to the scattering intensity and the frequency shift. The scattering intensity of the lowest frequency Eg mode is much weaker in I-phase than in M-phase.The frequency shifts of the scattering peaks are higher in I-phase by several cm^ than in M-phase. These behaviours may be explained by the 2-band crossing model which has been proposed by Zeiger for the high tempeqature transition in ( V_Cr_x)_2O_3

    Interacting dimers on the honeycomb lattice: An exact solution of the five-vertex model

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    The problem of close-packed dimers on the honeycomb lattice was solved by Kasteleyn in 1963. Here we extend the solution to include interactions between neighboring dimers in two spatial lattice directions. The solution is obtained by using the method of Bethe ansatz and by converting the dimer problem into a five-vertex problem. The complete phase diagram is obtained and it is found that a new frozen phase, in which the attracting dimers prevail, arises when the interaction is attractive. For repulsive dimer interactions a new first-order line separating two frozen phases occurs. The transitions are continuous and the critical behavior in the disorder regime is found to be the same as in the case of noninteracting dimers characterized by a specific heat exponent \a=1/2.Comment: latex, 29 pages + 7 figure

    Immune-modulation by polyclonal IgM treatment reduces atherosclerosis in hypercholesterolemic apoE−/− mice

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    AbstractObjectiveGamma-globulin treatment reduces experimental atherosclerosis by modulating immune function; however the effect of IgM on atherosclerosis is not known. We investigated the effect of serum-derived, non-immune polyclonal IgM (Poly-IgM) on atherosclerosis in mice with advanced disease and also assessed its immune-modulatory effects.Methods and resultsAortic atherosclerosis was assessed in apoE−/− mice fed atherogenic diet starting at 6 weeks of age. In addition, mice were also subjected to perivascular cuff injury to the carotid artery at 25 weeks of age to induce accelerated atherosclerosis. At the time of injury, the mice were treated weekly with a commercially available Poly-IgM (0.4mg/mouse) or PBS for 4 weeks and euthanized at 29 weeks of age. Poly-IgM reduced aortic atherosclerosis, and reduced lesion size in the aortic sinus and injured carotid artery, without significant changes in serum cholesterol levels. Poly-IgM treatment was associated with increased anti-oxLDL IgG titers and a reduction in the % splenic CD4+ T cells compared to controls. The splenic CD4+ T cell cultured from the Poly-IgM treated mice had reduced proliferation in vitro compared with controls.ConclusionPoly-IgM treatment reduced aortic and accelerated carotid atherosclerosis in apoE−/− mice in association with increased anti-oxLDL IgG titers, and reduced number and proliferative function of splenic CD4+ T cells. Our study identifies a novel athero-protective and immunomodulatory role for non-immune polyclonal IgM

    Effect of Initial Disturbance on The Detonation Front Structure of a Narrow Duct

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    The effect of an initial disturbance on the detonation front structure in a narrow duct is studied by three-dimensional numerical simulation. The numerical method used includes a high resolution fifth-order weighted essentially non-oscillatory scheme for spatial discretization, coupled with a third order total variation diminishing Runge-Kutta time stepping method. Two types of disturbances are used for the initial perturbation. One is a random disturbance which is imposed on the whole area of the detonation front, and the other is a symmetrical disturbance imposed within a band along the diagonal direction on the front. The results show that the two types of disturbances lead to different processes. For the random disturbance, the detonation front evolves into a stable spinning detonation. For the symmetrical diagonal disturbance, the detonation front displays a diagonal pattern at an early stage, but this pattern is unstable. It breaks down after a short while and it finally evolves into a spinning detonation. The spinning detonation structure ultimately formed due to the two types of disturbances is the same. This means that spinning detonation is the most stable mode for the simulated narrow duct. Therefore, in a narrow duct, triggering a spinning detonation can be an effective way to produce a stable detonation as well as to speed up the deflagration to detonation transition process.Comment: 30 pages and 11 figure

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.

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    Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

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    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
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