8,181 research outputs found

    Charmless Two-body B(Bs)VPB(B_s)\to VP decays In Soft-Collinear-Effective-Theory

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    We provide the analysis of charmless two-body BVPB\to VP decays under the framework of the soft-collinear-effective-theory (SCET), where V(P)V(P) denotes a light vector (pseudoscalar) meson. Besides the leading power contributions, some power corrections (chiraly enhanced penguins) are also taken into account. Using the current available BPPB\to PP and BVPB\to VP experimental data on branching fractions and CP asymmetry variables, we find two kinds of solutions in χ2\chi^2 fit for the 16 non-perturbative inputs which are essential in the 87 BPPB\to PP and BVPB\to VP decay channels. Chiraly enhanced penguins can change several charming penguins sizably, since they share the same topology. However, most of the other non-perturbative inputs and predictions on branching ratios and CP asymmetries are not changed too much. With the two sets of inputs, we predict the branching fractions and CP asymmetries of other modes especially BsVPB_s\to VP decays. The agreements and differences with results in QCD factorization and perturbative QCD approach are analyzed. We also study the time-dependent CP asymmetries in channels with CP eigenstates in the final states and some other channels such as Bˉ0/B0π±ρ\bar B^0/B^0\to\pi^\pm\rho^\mp and Bˉs0/Bs0K±K\bar B_s^0/B_s^0\to K^\pm K^{*\mp}. In the perturbative QCD approach, the (SP)(S+P)(S-P)(S+P) penguins in annihilation diagrams play an important role. Although they have the same topology with charming penguins in SCET, there are many differences between the two objects in weak phases, magnitudes, strong phases and factorization properties.Comment: 34 pages, revtex, 2 figures, published at PR

    Is f1(1420)f_1(1420) the partner of f1(1285)f_1(1285) in the 3P1^3P_1 qqˉq\bar{q} nonet?

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    Based on a 2×22\times 2 mass matrix, the mixing angle of the axial vector states f1(1420)f_1(1420) and f1(1285)f_1(1285) is determined to be 51.551.5^{\circ}, and the theoretical results about the decay and production of the two states are presented. The theoretical results are in good agreement with the present experimental results, which suggests that f1(1420)f_1(1420) can be assigned as the partner of f1(1285)f_1(1285) in the 3P1^3P_1 qqˉq\bar{q} nonet. We also suggest that the existence of f1(1510)f_1(1510) needs further experimental confirmation.Comment: Latex, 6 pages, to be published in Chin. Phys. let

    Endoscopic assisted adenoidectomy versus conventional curettage adenoidectomy: a meta-analysis of randomized controlled trials

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    Adenoidectomy, surgical removal of hypertrophic adenoids, is a common operation in children worldwide. The purpose of this study was to compare the operative effectiveness, and included total operative time, blood loss and complications, between endoscopic assisted adenoidectomy and conventional curettage adenoidectomy. EMBASE, PubMed, Cochrane Library, and China National Knowledge Infrastructure and symposiums and review articles were used to choose relevant randomized controlled trials. A meta-analysis was performed to analyze the data for total operative time, blood loss and complications. Seven studies fit the inclusion criteria, and included 331 patients treated with endoscopic assisted adenoidectomy, and 251 patients treated with conventional curettage adenoidectomy. The meta-analysis demonstrated that compared with conventional curettage adenoidectomy, endoscopic assisted adenoidectomy had a shorter operative time (SMD −1.09; 95 % CI −1.29 to −0.90; p < 0.00001), less blood loss (MD −19.74; 95 % CI −22.75 to −16.73; p < 0.00001), and fewer complications (OR 0.15; 95 % CI 0.07–0.35; p < 0.0001). Endoscopic assisted adenoidectomy has advantages over conventional curettage adenoidectomy with regard to total operative time, blood loss and complications

    1H-Benzimidazole-2(3H)-thione

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    The asymmetric unit of the title compound, C7H6N2S, contains one half-mol­ecule; the C and S atoms of the C=S group lie on a crystallographic mirror plane. In the crystal structure, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules

    4-[(E)-(2-Methoxy­phen­yl)imino­meth­yl]-N,N-dimethyl­aniline

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    In the title compound, C16H18N2O, the dihedral angle between the benzene rings is 38.5 (2)°. The crystal packing is stabilized by weak C—H⋯N and C—H⋯O inter­actions and aromatic π–π stacking [centroid–centroid separations = 3.620 (5) and 3.546 (4) Å]

    Research progress of diabetic retinopathy and gut microecology

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    According to the prediction of the International Diabetes Federation, global diabetes mellitus (DM) patients will reach 783.2 million in 2045. The increasing incidence of DM has led to a global epidemic of diabetic retinopathy (DR). DR is a common microvascular complication of DM, which has a significant impact on the vision of working-age people and is one of the main causes of blindness worldwide. Substantial research has highlighted that microangiopathy and chronic low-grade inflammation are widespread in the retina of DR. Meanwhile, with the introduction of the gut-retina axis, it has also been found that DR is associated with gut microecological disorders. The disordered structure of the GM and the destruction of the gut barrier result in the release of abnormal GM flora metabolites into the blood circulation. In addition, this process induced alterations in the expression of various cytokines and proteins, which further modulate the inflammatory microenvironment, vascular damage, oxidative stress, and immune levels within the retina. Such alterations led to the development of DR. In this review, we discuss the corresponding alterations in the structure of the GM flora and its metabolites in DR, with a more detailed focus on the mechanism of gut microecology in DR. Finally, we summarize the potential therapeutic approaches of DM/DR, mainly regulating the disturbed gut microecology to restore the homeostatic level, to provide a new perspective on the prevention, monitoring, and treatment of DR

    Cinnamyl 8-meth­oxy-2-oxo-2H-chromene-3-carboxyl­ate

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    In the crystal structure of the title compound, C20H16O5, the mol­ecule assumes an E configuration with the benzene ring and chromenecarboxyl group located on opposite ends of the C=C double bond. The chromene ring system and benzene ring are oriented at a dihedral angle of 74.66 (12)°. Weak inter­molecular C—H⋯O hydrogen bonding is present in the crystal structure
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