301 research outputs found

    Convolution-based means of gradient for fast eye center localization

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    Heavy Flavor Production at STAR

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    e present measurements on D0D^0 meson production via direct reconstruction of its hadronic decay channel D0β†’KΟ€D^0\to K\pi in minimum bias dd+Au and Au+Au collisions at sNN\sqrt{s_{NN}}=200 GeV with pTp_T up to ∼\sim3 GeV/cc. Non-photonic electron spectra from the charm semi-leptonic decays are analyzed from the same data set as well as in pp+pp collision at s\sqrt{s}=200 GeV using the STAR Time-of-Flight (TOF) and Barrel EMC (BEMC) detectors, respectively. Results of the charm-decayed single muon (prompt muon) spectra are also presented at low pTp_T in Au+Au collisions measured by the TOF detector. The charm production total cross-section per nucleon-nucleon collision is measured to be 1.26Β±\pm0.09(stat.)Β±\pm0.23(sys.) mb in minimum bias Au+Au collisions, which is consistent with the NbinN_{bin} scaling compared to 1.4Β±0.2Β±\pm0.2\pm0.4 mb in minimum bias dd+Au collisions, and supports the idea that charm quarks should be produced mostly via parton fusion at early stage in relativistic heavy-ion collisions. A Blast-Wave model fit to the low pTp_T (<2<2 GeV/c) non-photonic electrons, prompt muons and D0D^0 spectra shows that charm hadrons may kinetically freeze-out earlier than light hadrons with a smaller collective velocity. The nuclear modification factors (RAAR_{AA}) of the non-photonic electrons in central Au+Au collisions are significantly below unity at pT>∼p_T>\sim2 GeV/cc, which indicates a significant amount of energy loss for heavy quarks in Au+Au collisions. The charm transverse momentum distribution must have been modified by the hot and dense matter created in central Au+Au collisions at RHIC.Comment: 7 pages, 4 figures, proceedings for the Strange Quark Matter 2006 conferenc

    Kβˆ—(892)K^{*}(892) Production in Au+Au and pp Collisions at sNN\sqrt{s_{NN}} = 200GeV at STAR

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    Mid-rapidity Kβˆ—0(892)β†’KΟ€K^{*0}(892)\to K\pi and Kβˆ—Β±(892)β†’KS0π±K^{*\pm}(892)\to K_S^0\pi^{\pm} are measured in Au+Au and pp collisions at sNN\sqrt{s_{NN}}=200GeV using the STAR detector at RHIC. The Kβˆ—0(892)K^{*0}(892) mass is systematically shifted at small transverse momentum for both Au+Au and pp collisions. The Kβˆ—0(892)K^{*0}(892) transverse mass spectra are measured in Au+Au collisions at different centralities and in pp collisions. The Kβˆ—0(892)K^{*0}(892) mean transverse momentum as a function of the collision centrality is compared to those of identified Ο€βˆ’\pi^{-}, Kβˆ’K^{-} and pΛ‰\bar{p}. The Kβˆ—/KK^{*}/K and Ο•/Kβˆ—\phi/K^{*} ratios are compared to measurements in A+A, pppp, pΛ‰p\bar{p}p, e+eβˆ’e^{+}e^{-} collisions at various colliding energies. The physics implications of these measurements are also discussed.Comment: 6 pages, 4 figures, proceedings of Strange Quarks in Matter (SQM2003), Atlantic Beach, USA, to be published in J. Phys.

    B --> Phi K_S and Supersymmetry

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    The rare decay B --> Phi K_S is a well-known probe of physics beyond the Standard Model because it arises only through loop effects yet has the same time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on B(B_s --> mu mu). On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in B --> Psi K_S, Delta M_s, B --> X_s gamma and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions of other recent works on this topic. Added discussions & plots for gluino mass dependence and effects of theoretical uncertaintie

    A combinatorial TIR1/AFB–Aux/IAA co-receptor system for differential sensing of auxin

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    The plant hormone auxin regulates virtually every aspect of plant growth and development. Auxin acts by binding the F-box protein transport inhibitor response 1 (TIR1) and promotes the degradation of the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) transcriptional repressors. Here we show that efficient auxin binding requires assembly of an auxin co-receptor complex consisting of TIR1 and an Aux/IAA protein. Heterologous experiments in yeast and quantitative IAA binding assays using purified proteins showed that different combinations of TIR1 and Aux/IAA proteins form co-receptor complexes with a wide range of auxin-binding affinities. Auxin affinity seems to be largely determined by the Aux/IAA. As there are 6 TIR1/AUXIN SIGNALING F-BOX proteins (AFBs) and 29 Aux/IAA proteins in Arabidopsis thaliana, combinatorial interactions may result in many co-receptors with distinct auxin-sensing properties. We also demonstrate that the AFB5–Aux/IAA co-receptor selectively binds the auxinic herbicide picloram. This co-receptor system broadens the effective concentration range of the hormone and may contribute to the complexity of auxin response

    Expression of PRB, FKBP52 and HB-EGF Relating with Ultrasonic Evaluation of Endometrial Receptivity

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    Background: To explore the molecular basis of the different ultrasonic patterns of the human endometrium, and the molecular marker basis of local injury. Methodology/Principal Findings: The mRNA and protein expression of FKBP52, progesterone receptor A (PRA), progesterone receptor B (PRB), and HB-EGF were detected in different patterns of the endometrium by real-time RTPCR and immunohistochemistry. There were differences in the mRNA and protein expression of FKBP52, PRB, and HB-EGF in the triple line (Pattern A) and homogeneous (Pattern C) endometrium in the window of implantation. No difference was detected in PRA expression. After local injury, the mRNA expression of HB-EGF significantly increased. In contrast, there was no difference in the mRNA expression of FKBP52, PRB, or PRA. The protein expression of FKBP52, PRB, and HB-EGF increased after local injury. There was no difference in the PRA expression after local injury. Conclusions: PRB, FKBP52, and HB-EGF may be the molecular basis for the classification of the ultrasonic patterns. HB-EGF may be the molecular basis of local injury. Ultrasonic evaluation on the day of ovulation can be effective in predicting the outcome of implantation

    The Role of Cilostazol, a Phosphodiesterase 3 Inhibitor, on Oocyte Maturation and Subsequent Pregnancy in Mice

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    It is important to identify effective contraceptive drugs that cause minimal disruption to physiological processes. Phosphodiesterase 3 (PDE3) inhibitors suppress meiosis in oocytes by decreasing the level of cAMP and blocking the extrusion of the first polar body. In this study, we tested the PDE3 inhibitor, cilostazol, as a potential contraceptive agent. The effects of cilostazol treatment in vitro and in vivo on the suppression of oocyte maturation in a mouse model were investigated. The results indicated that treatment with increasing concentrations of cilostazol led to a dose-dependent arrest in meiosis progression. The effective in vitro concentration was 1 Β΅M and was 300 mg/kg in vivo. The effect of cilostazol was reversible. After removal of the drug, meiosis resumed and mouse oocytes matured in vitro, and showed normal chromosome alignment and spindle organization. After fertilization using an ICSI method, the oocytes showed normal morphology, fertilization rate, embryo cleavage, blastocyst formation, and number of viable pups when compared with controls. The offspring showed similar body weight and fertility. In vivo, the mice became infertile if the drug was injected sequentially, and became pregnant following discontinuation of cilostazol. More importantly, no side effects of cilostazol were observed in treated female mice as demonstrated by blood pressure and heart rate monitoring. It is concluded that cilostazol, a drug routinely used for intermittent claudication, can effectively inhibit oocyte maturation in vitro and in vivo, does not affect the developmental potential of oocytes following drug removal and has few side effects in female mice treated with this drug. These findings suggest that cilostazol may be a potential new contraceptive agent that may facilitate an efficacy and safety study of this drug

    Comprehensive Analysis of Leukocytes, Vascularization and Matrix Metalloproteinases in Human Menstrual Xenograft Model

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    In our previous study, menstrual-like changes in mouse were provoked through the pharmacologic withdrawal of progesterone with mifepristone following induction of decidualization. However, mouse is not a natural menstruation animal, and the menstruation model using external stimuli may not truly reflect the occurrence and development of the human menstrual process. Therefore, we established a model of menstruation based on human endometrial xenotransplantation. In this model, human endometrial tissues were transplanted subcutaneously into SCID mice that were ovarectomized and supplemented with estrogen and progestogen by silastic implants with a scheme imitating the endocrinological milieu of human menstrual cycle. Morphology, hormone levels, and expression of vimentin and cytokeratin markers were evaluated to confirm the menstrual-like changes in this model. With 28 days of hormone treatment, transplanted human endometrium survived and underwent proliferation, differentiation and disintegration, similar to human endometrium in vivo. Human CD45+ cells showed a peak of increase 28 days post-transplantation. Three days after progesterone withdrawal, mouse CD45+ cells increased rapidly in number and were significantly greater than human CD45+ cell counts. Mouse CD31+ blood vascular-like structures were detected in both transplanted and host tissues. After progesterone withdrawal, the expression levels of matrix metalloproteinases (MMP) 1, 2, and 9 were increased. In summary, we successfully established a human endometrial xenotransplantation model in SCID mice, based on the results of menstrual-like changes in which MMP-1, 2 and 9 are involved. We showed that leukocytes are originated from in situ proliferation in human xenografts and involved in the occurrence of menstruation. This model will help to further understand the occurrence, growth, and differentiation of the endometrium and the underlying mechanisms of menstruation
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