239 research outputs found

    Top quark decays with flavor violation in the B-LSSM

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    The decays of top quark tcγ,  tcg,  tcZ,  tcht\rightarrow c\gamma,\;t\rightarrow cg,\;t\rightarrow cZ,\;t\rightarrow ch are extremely rare processes in the standard model (SM). The predictions on the corresponding branching ratios in the SM are too small to be detected in the future, hence any measurable signal for the processes at the LHC is a smoking gun for new physics. In the extension of minimal supersymmetric standard model with an additional local U(1)BLU(1)_{B-L} gauge symmetry (B-LSSM), new gauge interaction and new flavor changing interaction affect the theoretical evaluations on corresponding branching ratios of those processes. In this work, we analyze those processes in the B-LSSM, under a minimal flavor violating assumption for the soft breaking terms. Considering the constraints from updated experimental data, the numerical results imply Br(tcγ)5×107Br(t\rightarrow c\gamma)\sim5\times10^{-7}, Br(tcg)2×106Br(t\rightarrow cg)\sim2\times10^{-6}, Br(tcZ)4×107Br(t\rightarrow cZ)\sim4\times10^{-7} and Br(tch)3×109Br(t\rightarrow ch)\sim3\times10^{-9} in our chosen parameter space. Simultaneously, new gauge coupling constants gB,  gYBg_{_B},\;g_{_{YB}} in the B-LSSM can also affect the numerical results of Br(tcγ,  cg,  cZ,  ch)Br(t\rightarrow c\gamma,\;cg,\;cZ,\;ch).Comment: 20 pages, 4 figures, published in EPJC. arXiv admin note: substantial text overlap with arXiv:1803.0990

    Effective Silencing of Sry Gene with RNA Interference in Developing Mouse Embryos Resulted in Feminization of XY Gonad

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    Delivering siRNA or shRNA into the developing embryos is still a main challenge to use of RNAi in mammalian systems. Here we analyze several factors influencing RNAi-mediated silencing of Sry gene, which is a tightly controlled spatiotemporal expressed gene and only shortly expressed in developing mouse embryo gonad. A Sry gene-specific shRNAs expression vector (pSilencer4.1/Sry565) was constructed. The shRNA constructs were mixed with polyethylenimines (PEIs) to form a complex and then injected into pregnant mice though tail vein. Our results showed that Sry gene was downregulated significantly in developing embryos. Further study revealed that knocking-down of Sry expression resulted in feminization of gonad development in mouse embryos and the expression level of Sox9 and Wt1 gene was also significantly changed by downregulation of Sry. The transfection efficiency is associated with the amount of plasmid DNA injection, injection time, injection speed, and volume. Our studies suggest that transplacental RNAi could be implemented by tail vein injection of plasmid vector into pregnant mice

    Characteristics and management of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in a tertiary hospital

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    Background: The emergence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases is rare. We report an occurrence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases in a Chinese tertiary care hospital from November 2010 to December 2012.Methods: The clinical characteristics of 30 patients were described. The genetic relationship of isolates was determined by pulsed-field gel electrophoresis (PFGE). Carbapenemases were detected by modified Hodge test (MHT) and polymerase chain reactions (PCRs). Amplicons were sequenced and blasted to determine the genotype.Results: Most infected patients were from intensive care unit and had complex and serious underlying illnesses requiring mechanical ventilation. PFGE revealed that Klebsiella pneumoniae showed two major PFGE types. Two Klebsiella oxytoca had an indistinguishable PFGE pattern, while four Enterobacter cloacae were different strains. The sequencing studies showed Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in the 23 infected patients. The majority of patients had infections with the carbapenemase-producing Enterobacteriaceae (CPE) strain, most were successfully treated with a range of antibiotics and discharged.Conclusion: It is important to maintain a high index of suspicion to screen for carbapenemase-producing Enterobacteriaceae strains. Rapid identification of these strains and implementation of stringent procedures are the key to prevent major outbreaks in a hospital setting.Keywords: Carbapenemase, Enterobacteriaceae, IMP-4, IMP-8, clinical outcom

    Influence of Yb:YAG laser beam parameters on Haynes 188 weld fusion zone microstructure and mechanical properties

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    The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm1, and spot sizes between 160 and 320 lm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min�1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties

    Process optimization and thermodynamic property analysis of brown rice cooking quality improvement by low temperature plasma technology

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    In order to solve the problems of long cooking time and rough taste of brown rice, a new technology based on low temperature plasma treatment was put forward. Taking brown rice as raw material, the effects of glow intensity, treatment time and moisture content in low-temperature plasma processing on cooking time and solid loss rate of brown rice were studied, and the thermodynamic properties of white rice, brown rice and low-temperature plasma treated brown rice were analyzed by DSC. On the basis of single factor experiment, orthogonal experiment parameters of optimizing the low-temperature plasma process was glow intensity 1.8a, treatment time 2 min, moisture content 9.33%, then cooking time was about 25.31 min under this condition, solid loss rate was 19.18 mg/g. Thermodynamic analysis shows that low temperature plasma treatment can reduce the thermal phase transition temperature, termination temperature and enthalpy of brown rice. The results can be used as reference for low temperature plasma in brown rice production

    A stable wavelength-spacing-tunable dual-wavelength single-longitudinal-mode fiber ring laser based on a DMD filter

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    A stable single-longitudinal-mode dual-wavelength( SLM-DW) multiple ring fiber laser with a tunable wavelength spacing was proposed and demonstrated. In the multiple ring cavities, the mode selection is made by the tunable digital micro-mirror device( DMD) filter and two different length passive sub-ring cavities. The DMD filter can select and couple any two wavelengths from the gain spectrum of the erbium-doped fiber( EDF). The SLM lasing is guaranteed by the two sub-ring cavities which serve as a mode filter. The stable and uniform dual wave length oscillation is obtained by the highly-nonlinear photonic crystal fiber( HN-PCF),which can generate the four-wave-mixing( FWM) effective. By loading different gratings on the DMD filter without any mechanically shift,the tunable wavelength spacing from appropriately 0. 165 nm to 1. 08 nm within a tuning accuracy of 0. 055 nm is achieved at room temperature

    Characteristics and management of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in a tertiary hospital.

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    Background: The emergence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases is rare. We report an occurrence of Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemases in a Chinese tertiary care hospital from November 2010 to December 2012. Methods: The clinical characteristics of 30 patients were described. The genetic relationship of isolates was determined by pulsed-field gel electrophoresis (PFGE). Carbapenemases were detected by modified Hodge test (MHT) and polymerase chain reactions (PCRs). Amplicons were sequenced and blasted to determine the genotype. Results: Most infected patients were from intensive care unit and had complex and serious underlying illnesses requiring mechanical ventilation. PFGE revealed that Klebsiella pneumoniae showed two major PFGE types. Two Klebsiella oxytoca had an indistinguishable PFGE pattern, while four Enterobacter cloacae were different strains. The sequencing studies showed Enterobacteriaceae harboring IMP-4 or IMP-8 carbapenemase in the 23 infected patients. The majority of patients had infections with the carbapenemase-producing Enterobacteriaceae (CPE) strain, most were successfully treated with a range of antibiotics and discharged. Conclusion: It is important to maintain a high index of suspicion to screen for carbapenemase-producing Enterobacteriaceae strains. Rapid identification of these strains and implementation of stringent procedures are the key to prevent major outbreaks in a hospital setting. Keywords

    SOX40L: An Important Infl ammatory Mediator in Adult Bronchial Asthma

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    Abstract Introduction: The role of soluble OX40 ligand (sOX40L) in adult bronchial asthma is unclear. This study aims to determine the serum concentrations of sOX40L in adult patients with bronchial asthma, and discussed its relationship with pulmonary function. Materials and Methods: We measured the pulmonary function using the spirometer and detected the serum concentrations of sOX40L by enzyme linked immunosorbent assay (ELISA) in 19 healthy persons in the control group, 58 acute asthmatic adult patients who were grouped according to their disease severity: 18 mild grade, 24 moderate grade, 16 severe grade, and 24 persons in a stable asthmatic group. Results: The serum concentrations of sOX40L in asthmatic adult patients (6.80 ± 4.95 ng/L) were distinctly higher than those in the control group (3.98 ± 2.83 ng/L, P <0.05), and they were negatively correlated with pulmonary function indexes (FEV1%, FVC%, FEV1/FVC) (r = -0.754, P <0.01, r = -0.557, P <0.01, r = -0.457, P <0.01, respectively). Moreover, the serum concentrations of sOX40L showed obvious differences among control, mild, moderate, and severe groups (3.98 ± 2.83, 4.87 ± 1.89, 6.97 ± 5.91, 8.71 ± 5.18 ng/L, respectively; P <0.01). The concentrations of sOX40L decreased to the same extent as the control group after therapeutic treatments were provided to the asthmatic adult patients. Conclusion: The concentrations of sOX40L were found to be high in adult asthmatic patients and were associated with the severity of the disease. Therefore, sOX40L could be a potential infl ammatory mediator in the pathogenesis of asthma

    A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

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    We established a method on measuring the \dzdzb mixing parameter yy for BESIII experiment at the BEPCII e+ee^+e^- collider. In this method, the doubly tagged ψ(3770)D0D0\psi(3770) \to D^0 \overline{D^0} events, with one DD decays to CP-eigenstates and the other DD decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/πe/\pi separation, a likelihood approach, which combines the dE/dxdE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of yy to be 0.007 based on a 20fb120fb^{-1} fully simulated MC sample.Comment: 6 pages, 7 figure
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