199 research outputs found

    Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

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    The decay channel Οˆβ€²β†’Ο€+Ο€βˆ’J/ψ(J/Οˆβ†’Ξ³ppΛ‰)\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) is studied using a sample of 1.06Γ—1081.06\times 10^8 Οˆβ€²\psi^\prime events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the ppΛ‰p\bar{p} invariant mass spectrum. The enhancement can be fit with an SS-wave Breit-Wigner resonance function with a resulting peak mass of M=1861βˆ’13+6(stat)βˆ’26+7(syst)MeV/c2M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2 and a narrow width that is Ξ“<38MeV/c2\Gamma<38 {\rm MeV/}c^2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

    The Potential Role of ORM2 in the Development of Colorectal Cancer

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    Colorectal cancer (CRC) is the third most common malignancy in the world. The risk of death is closely correlated to the stage of CRC at the time of primary diagnosis. Therefore, there is a compelling need for the identification of blood biomarkers that can enable early detection of CRC. We used a quantitative proteomic approach with isobaric labeling (iTRAQ) to examine changes in the plasma proteome of 10 patients with CRC compared to healthy volunteers. Enzyme-Linked Immunosorbnent Assay (ELISA) and Western blot were used for further validation. In our quantitative proteomics analysis, we detected 75 human plasma proteins with more than 95% confidence using iTRAQ labeling in conjunction with microQ-TOF MS. 9 up-regulated and 4 down-regulated proteins were observed in the CRC group. The ORM2 level in plasma was confirmed to be significantly elevated in patients suffering from CRC compared with the controls. ORM2 expression in CRC tissues was significantly increased compared with that in corresponding adjacent normal mucous tissues (P<0.001). ITRAQ together with Q-TOF/MS is a sensitive and reproducible technique of quantitative proteomics. Alteration in expression of ORM2 suggests that ORM2 could be used as a potential biomarker in the diagnosis of CRC

    Acute Effects of Sex Steroid Hormones on Susceptibility to Cardiac Arrhythmias: A Simulation Study

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    Acute effects of sex steroid hormones likely contribute to the observation that post-pubescent males have shorter QT intervals than females. However, the specific role for hormones in modulating cardiac electrophysiological parameters and arrhythmia vulnerability is unclear. Here we use a computational modeling approach to incorporate experimentally measured effects of physiological concentrations of testosterone, estrogen and progesterone on cardiac ion channel targets. We then study the hormone effects on ventricular cell and tissue dynamics comprised of Faber-Rudy computational models. The β€œfemale” model predicts changes in action potential duration (APD) at different stages of the menstrual cycle that are consistent with clinically observed QT interval fluctuations. The β€œmale” model predicts shortening of APD and QT interval at physiological testosterone concentrations. The model suggests increased susceptibility to drug-induced arrhythmia when estradiol levels are high, while testosterone and progesterone are apparently protective. Simulations predict the effects of sex steroid hormones on clinically observed QT intervals and reveal mechanisms of estrogen-mediated susceptibility to prolongation of QT interval. The simulations also indicate that acute effects of estrogen are not alone sufficient to cause arrhythmia triggers and explain the increased risk of females to Torsades de Pointes. Our results suggest that acute effects of sex steroid hormones on cardiac ion channels are sufficient to account for some aspects of gender specific susceptibility to long-QT linked arrhythmias

    Improved Measurement of Electron Antineutrino Disappearance at Daya Bay

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    Measurement of the matrix element for the decay Ξ·β€²β†’Ξ·Ο€ +Ο€ -

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    The Dalitz plot of Ξ·βŠƒβ€²β†’Ξ·Ο€βŠƒ+Ο€βŠƒ- decay is studied using (225.2Β±2.8)Γ—106 J/ψ events collected with the BESIII detector at the BEPCII eβŠƒ+eβŠƒ- collider. With the largest sample of Ξ·βŠƒβ€² decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/Οˆβ†’Ξ³Ξ·βŠƒβ€² is determined to be (4.84Β±0.03Β±0.24)Γ—10βŠƒ-3, where the first error is statistical and the second systematic. Β© 2011 American Physical Society.published_or_final_versio

    First observation of the decays χcJ→π0π0π0π0

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    We present a study of the P-wave spin-triplet charmonium Ο‡ cJ decays (J=0, 1, 2) into Ο€0Ο€0Ο€0Ο€0. The analysis is based on 106Γ—106 ΟˆβŠƒβ€² decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the Ο€0Ο€0Ο€0Ο€0 hadronic final state is observed for the first time. We measure the branching fractions B(Ο‡ c0β†’Ο€0Ο€0Ο€0Ο€0)=(3.34Β±0. 06Β±0.44)Γ—10βŠƒ-3, B(Ο‡ c1β†’Ο€0Ο€0Ο€0Ο€0) =(0.57Β±0.03Β±0.08)Γ—10βŠƒ-3, and B(Ο‡ c2β†’Ο€0Ο€0Ο€0Ο€0)=(1.21Β±0.05Β±0.16) Γ—10βŠƒ-3, where the uncertainties are statistical and systematical, respectively. Β© 2011 American Physical Society.published_or_final_versio

    Higher-order multipole amplitude measurement in ψ β€²β†’Ξ³Ο‡ c2

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    Using 106Γ—106 ψ β€² events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition ψ β€²β†’Ξ³Ο‡ c2β†’Ξ³Ο€ +Ο€ -/Ξ³K +K - are measured. A fit to the Ο‡ c2 production and decay angular distributions yields M2=0.046Β±0. 010Β±0.013 and E3=0.015Β±0.008Β±0.018, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with 4.4Οƒ statistical significance and is consistent with the charm quark having no anomalous magnetic moment. Β© 2011 American Physical Society.published_or_final_versio
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