404 research outputs found

    Anti-depressant effect of Paeonia lactiflora Pall extract in rats

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    Purpose: To explore the effect of Paeonia lactiflora Pall. extract on depression in rats.Methods: Various doses (150, 300 and 600 mg/kg) of Paeonia lactiflora Pall. extract (PLPE) were orally administered to three groups of rats of 10 each, respectively, suffering from depression for 14 days. Fluoxetine was used as positive control. Tail suspension, forced swimming and monoamine oxidase (MAO) tests were carried out on the rats.Results: A dose-dependent reduction in rat immobility was observed. The effect of PLPE at the highest dose (600 mg/kg) was more potent than that of the reference antidepressant, fluoxetine. PLPE, at a dose ≥ 150 mg/kg significantly inhibited MAO A activity in rat whole brain in a dose-dependent manner (p < 0.01); however, only oral administration of PLPE at a dose of 600 mg/kg produced observable MAO B inhibitory activity in rat brain (p < 0.01). Only fluoxetine showed a tendency to inhibit both MAO A and B activities in animal brain. Neither PLPE nor fluoxetine, at the doses tested, produced significant effects on locomotor activity.Conclusion: The results suggest that Paeonia lactiflora Pall is a potential agent for the treatment of depression in humans.Keywords: Paeonia lactiflora, Depression, Tail suspension test, Forced swimming tes

    Finite Element Analysis of A Retrieved Custom-Made Knee Prosthesis

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    Custom-made knee prostheses have been widely used to reconstruct the function of the lower limb in bone tumor resections. A custom-made tumor knee prosthesis was retrieved on account of prosthesis loosening post-surgery. Misalignment between the anatomical axis of the femur and the axis of the femoral stem as well as the material loss at the posterior region of the tibial plateau were considered to be the primary causes of the failure. Based on this hypothesis, finite element analysis was performed to investigate the contact mechanics of the prosthesis while implanted in vivo. The maximum deformation at the femur was 0.59 and 1.17 mm when the misalignment angle was 3° and 6°, respectively. Besides, the maximum contact pressure at the tibial plateau was 44.88 MPa at an extremely high flexion of angle 135° during squatting or kneeling. Uneven stress distribution at the femur, which came from the misalignment, was the main cause of loosening, which was aggravated indirectly with the material loss at the posterior region of the tibial plateau. Optimized prosthesis design and appropriate selection, with accurate surgical positioning and targeted rehabilitation training programme are important considerations for prolonging life-span of prostheses in vivo

    An Updated Search of Steady TeV γ\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

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    Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV γ\gamma-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.00.0^{\circ} to 60.060.0^{\circ} in declination (Dec) range, no new TeV γ\gamma-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV γ\gamma-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn

    Observation of ηcωω\eta_c\to\omega\omega in J/ψγωωJ/\psi\to\gamma\omega\omega

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    Using a sample of (1310.6±7.0)×106(1310.6\pm7.0)\times10^6 J/ψJ/\psi events recorded with the BESIII detector at the symmetric electron positron collider BEPCII, we report the observation of the decay of the (11S0)(1^1 S_0) charmonium state ηc\eta_c into a pair of ω\omega mesons in the process J/ψγωωJ/\psi\to\gamma\omega\omega. The branching fraction is measured for the first time to be B(ηcωω)=(2.88±0.10±0.46±0.68)×103\mathcal{B}(\eta_c\to\omega\omega)= (2.88\pm0.10\pm0.46\pm0.68)\times10^{-3}, where the first uncertainty is statistical, the second systematic and the third is from the uncertainty of B(J/ψγηc)\mathcal{B}(J/\psi\to\gamma\eta_c). The mass and width of the ηc\eta_c are determined as M=(2985.9±0.7±2.1)M=(2985.9\pm0.7\pm2.1)\,MeV/c2c^2 and Γ=(33.8±1.6±4.1)\Gamma=(33.8\pm1.6\pm4.1)\,MeV.Comment: 13 pages, 6 figure

    First observations of hch_c \to hadrons

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    Based on (4.48±0.03)×108(4.48 \pm 0.03) \times 10^{8} ψ(3686)\psi(3686) events collected with the BESIII detector, five hch_c hadronic decays are searched for via process ψ(3686)π0hc\psi(3686) \to \pi^0 h_c. Three of them, hcppˉπ+πh_c \to p \bar{p} \pi^+ \pi^-, π+ππ0\pi^+ \pi^- \pi^0, and 2(π+π)π02(\pi^+ \pi^-) \pi^0 are observed for the first time, with statistical significances of 7.4σ\sigma, 4.9σ4.9\sigma, and 9.1σ\sigma, and branching fractions of (2.89±0.32±0.55)×103(2.89\pm0.32\pm0.55)\times10^{-3}, (1.60±0.40±0.32)×103(1.60\pm0.40\pm0.32)\times10^{-3}, and (7.44±0.94±1.56)×103(7.44\pm0.94\pm1.56)\times10^{-3}, respectively, where the first uncertainties are statistical and the second systematic. No significant signal is observed for the other two decay modes, and the corresponding upper limits of the branching fractions are determined to be B(hc3(π+π)π0)<8.7×103B(h_c \to 3(\pi^+ \pi^-) \pi^0)<8.7\times10^{-3} and B(hcK+Kπ+π)<5.8×104B(h_c \to K^+ K^- \pi^+ \pi^-)<5.8\times10^{-4} at 90% confidence level.Comment: 17 pages, 16 figure

    Measurements of Weak Decay Asymmetries of Λc+pKS0\Lambda_c^+\to pK_S^0, Λπ+\Lambda\pi^+, Σ+π0\Sigma^+\pi^0, and Σ0π+\Sigma^0\pi^+

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    Using e+eΛc+Λˉce^+e^-\to\Lambda_c^+\bar\Lambda_c^- production from a 567 pb1^{-1} data sample collected by BESIII at 4.6 GeV, a full angular analysis is carried out simultaneously on the four decay modes of Λc+pKS0\Lambda_c^+\to pK_S^0, Λπ+\Lambda \pi^+, Σ+π0\Sigma^+\pi^0, and Σ0π+\Sigma^0\pi^+. For the first time, the Λc+\Lambda_c^+ transverse polarization is studied in unpolarized e+ee^+e^- collisions, where a non-zero effect is observed with a statistical significance of 2.1σ\sigma. The decay asymmetry parameters of the Λc+\Lambda_c^+ weak hadronic decays into pKS0pK_S^0, Λπ+\Lambda\pi^+, Σ+π0\Sigma^+\pi^0 and Σ0π+\Sigma^0\pi^+ are measured to be 0.18±0.43(stat)±0.14(syst)0.18\pm0.43(\rm{stat})\pm0.14(\rm{syst}), 0.80±0.11(stat)±0.02(syst)-0.80\pm0.11(\rm{stat})\pm0.02(\rm{syst}), 0.57±0.10(stat)±0.07(syst)-0.57\pm0.10(\rm{stat})\pm0.07(\rm{syst}), and 0.73±0.17(stat)±0.07(syst)-0.73\pm0.17(\rm{stat})\pm0.07(\rm{syst}), respectively. In comparison with previous results, the measurements for the Λπ+\Lambda\pi^+ and Σ+π0\Sigma^+\pi^0 modes are consistent but with improved precision, while the parameters for the pKS0pK_S^0 and Σ0π+\Sigma^0\pi^+ modes are measured for the first time

    Search for the decay J/ψγ+invisibleJ/\psi\to\gamma + \rm {invisible}

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    We search for J/ψJ/\psi radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the J/ψJ/\psi produced through the process ψ(3686)π+πJ/ψ\psi(3686)\to\pi^+\pi^-J/\psi in a data sample of (448.1±2.9)×106(448.1\pm2.9)\times 10^6 ψ(3686)\psi(3686) decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2  GeV/c2\mathrm{\ Ge\kern -0.1em V}/c^2. The upper limit corresponding to an invisible particle with zero mass is 7.0×107\times 10^{-7} at the 90\% confidence level

    Observation of D+f0(500)e+νeD^+ \to f_0(500) e^+\nu_e and Improved Measurements of Dρe+νeD \to\rho e^+\nu_e

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    Using a data sample corresponding to an integrated luminosity of 2.93~fb1^{-1} recorded by the BESIII detector at a center-of-mass energy of 3.7733.773 GeV, we present an analysis of the decays Dˉ0π+π0eνˉe\bar{D}^0\to\pi^+\pi^0 e^-\bar{\nu}_e and D+ππ+e+νeD^+\to\pi^-\pi^+ e^+\nu_e. By performing a partial wave analysis, the π+π\pi^+\pi^- SS-wave contribution to D+ππ+e+νeD^+\to\pi^-\pi^+ e^+\nu_e is observed to be (25.7±1.6±1.1)(25.7\pm1.6\pm1.1)% with a statistical significance greater than 10σ\sigma, besides the dominant PP-wave contribution. This is the first observation of the SS-wave contribution. We measure the branching fractions B(D0ρe+νe)=(1.445±0.058±0.039)×103\mathcal{B}(D^{0} \to \rho^- e^+ \nu_e) = (1.445\pm 0.058 \pm 0.039) \times10^{-3}, B(D+ρ0e+νe)=(1.860±0.070±0.061)×103\mathcal{B}(D^{+} \to \rho^0 e^+ \nu_e) = (1.860\pm 0.070 \pm 0.061) \times10^{-3}, and B(D+f0(500)e+νe,f0(500)π+π)=(6.30±0.43±0.32)×104\mathcal{B}(D^{+} \to f_0(500) e^+ \nu_e, f_0(500)\to\pi^+\pi^-) = (6.30\pm 0.43 \pm 0.32) \times10^{-4}. An upper limit of B(D+f0(980)e+νe,f0(980)π+π)<2.8×105\mathcal{B}(D^{+} \to f_0(980) e^+ \nu_e, f_0(980)\to\pi^+\pi^-) < 2.8 \times10^{-5} is set at the 90% confidence level. We also obtain the hadronic form factor ratios of Dρe+νeD\to \rho e^+\nu_e at q2=0q^{2}=0 assuming the single-pole dominance parameterization: rV=V(0)A1(0)=1.695±0.083±0.051r_{V}=\frac{V(0)}{A_{1}(0)}=1.695\pm0.083\pm0.051, r2=A2(0)A1(0)=0.845±0.056±0.039r_{2}=\frac{A_{2}(0)}{A_{1}(0)}=0.845\pm0.056\pm0.039

    Complete Measurement of the &#923; Electromagnetic Form Factors

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    Observation of ηc→ωω in J/ψ→γωω

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