3,417 research outputs found

    Predominant cultivable subgingival flora of renal transplant recipients

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    Studies on the clinical significance of nonesterified and total cholesterol in urine

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    Gas-liquid chromatographic determinations of nonesterified and total urinary cholesterol were performed in 137 normals, 264 patients with various internal diseases without evidence of neoplasias or diseases of the kidney or urinary tract, 497 patients with malignancies and 236 patients with diseases of the kidney, urinary tract infections or prostatic adenoma with residual urine. A normal range (mean±2 SD) of 0.2–2.2 mg/24 hours nonesterified cholesterol (NEC) and of 0.3–3.0 mg/24 hours total cholesterol (TC) was calculated. Values of urinary cholesterol excretion were independent of age and sex and did not correlate with cholesterol levels in plasma. Patients with various internal diseases, without evidence of neoplasias nor diseases of the kidney or obstruction of the urinary tract, showed normal urinary cholesterol excretions, as did patients with infections of the urinary tract. However, elevated urinary cholesterol was found in patients with diseases of the kidney or urinary tract obstruction (prostatic adenoma with residual urine), malignant diseases of the urogenital tract and metastasing carcinoma of the breast. In patients with other malignant diseases urinary cholesterol was usually normal. Lesions of the urothelial cell membranes are considered to be the most likely cause of urinary cholesterol hyperexcretion. The clinical value of urinary cholesterol determinations as a possible screening test for urogenital carcinomas in unselected populations is limited by lacking specificity, expensive methodology and low prevalence of the mentioned carcinomas, although elevated urinary cholesterol excretions have been observed in early clinical stages of urogenital cancers

    Isotope effect on the transition temperature TcT_c in Fe-based superconductors: the current status

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    The results of the Fe isotope effect (Fe-IE) on the transition temperature TcT_c obtained up to date in various Fe-based high temperature superconductors are summarized and reanalyzed by following the approach developed in [Phys. Rev. B 82, 212505 (2010)]. It is demonstrated that the very controversial results for Fe-IE on TcT_c are caused by small structural changes occurring simultaneously with the Fe isotope exchange. The Fe-IE exponent on TcT_c [αFe=(ΔTc/Tc)/(ΔM/M)\alpha_{\rm Fe}=-(\Delta T_c/T_c)/(\Delta M/M), MM is the isotope mass] needs to be decomposed into two components with the one related to the structural changes (αFestr\alpha_{\rm Fe}^{\rm str}) and the genuine (intrinsic) one (αFeint\alpha_{\rm Fe}^{\rm int}). The validity of such decomposition is further confirmed by the fact that αFeint\alpha_{\rm Fe}^{\rm int} coincides with the Fe-IE exponent on the characteristic phonon frequencies αFeph\alpha_{\rm Fe}^{\rm ph} as is reported in recent EXAFS and Raman experiments.Comment: 7 pages, 4 figures. The paper is partially based on the results published in [New J. Phys. 12, 073024 (2010) = arXiv:1002.2510] and [Phys. Rev. B 82, 212505 (2010) = arXiv:1008.4540

    Ipl1/aurora kinase suppresses S-CDK-driven spindle formation during prophase I to ensure chromosome integrity during meiosis

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    Cells coordinate spindle formation with DNA repair and morphological modifications to chromosomes prior to their segregation to prevent cell division with damaged chromosomes. Here we uncover a novel and unexpected role for Aurora kinase in preventing the formation of spindles by Clb5-CDK (S-CDK) during meiotic prophase I and when the DDR is active in budding yeast. This is critical since S-CDK is essential for replication during premeiotic S-phase as well as double-strand break induction that facilitates meiotic recombination and, ultimately, chromosome segregation. Furthermore, we find that depletion of Cdc5 polo kinase activity delays spindle formation in DDR-arrested cells and that ectopic expression of Cdc5 in prophase I enhances spindle formation, when Ipl1 is depleted. Our findings establish a new paradigm for Aurora kinase function in both negative and positive regulation of spindle dynamics

    Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions

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    During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph

    Iterative joint frequency offset and channel estimation for OFDM systems using first and second order approximation algorithms

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    [[abstract]]To implement an algorithm for joint estimation of carrier frequency offset (CFO) and channel impulse response (CIR) in orthogonal frequency division multiplexing (OFDM) systems, the maximum-likelihood criterion is commonly adopted. A major difficulty arises from the highly nonlinear nature of the log-likelihood function which renders local extrema or multiple solutions for the CFO and CIR estimators. Use of an approximation method coupled with an adaptive iteration algorithm has been a popular approach to ease problem solving. The approximation used in those existing methods is usually of the first order level. Here, in addition to a new first order approximation method, we also propose a second order approximation method. Further, for the part of the adaptive iteration algorithm, we adopt a new technique which will enable performance improvement. Our first order approximation method is found to outperform the existing ones in terms of estimation accuracies, tracking range, computation complexity, and convergence speed. As expected, our second order approximation method provides an even further improvement at the expense of higher computation complication.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]DE

    Search for Second-Generation Scalar Leptoquarks in ppˉ\bm{p \bar{p}} Collisions at s\sqrt{s}=1.96 TeV

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    Results on a search for pair production of second generation scalar leptoquark in ppˉp \bar{p} collisions at s\sqrt{s}=1.96 TeV are reported. The data analyzed were collected by the CDF detector during the 2002-2003 Tevatron Run II and correspond to an integrated luminosity of 198 pb1^{-1}. Leptoquarks (LQ) are sought through their decay into (charged) leptons and quarks, with final state signatures represented by two muons and jets and one muon, large transverse missing energy and jets. We observe no evidence for LQLQ production and derive 95% C.L. upper limits on the LQLQ production cross sections as well as lower limits on their mass as a function of β\beta, where β\beta is the branching fraction for LQμqLQ \to \mu q.Comment: 9 pages (3 author list) 5 figure

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
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