326 research outputs found

    B_c meson rare decays in the light-cone quark model

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    We investigate the rare decays Bc→Ds(1968)ℓℓˉB_c \rightarrow D_s(1968) \ell \bar{\ell} and Bc→Ds∗(2317)ℓℓˉB_c\rightarrow D_s^*(2317) \ell \bar{\ell} in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful to investigating the structure of BcB_c meson and to testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.Comment: 9 pages, 11 figures, version accepted for publication in EPJ

    Radiative and Semileptonic B Decays Involving Higher K-Resonances in the Final States

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    We study the radiative and semileptonic B decays involving a spin-JJ resonant KJ(∗)K_J^{(*)} with parity (−1)J(-1)^J for KJ∗K_J^* and (−1)J+1(-1)^{J+1} for KJK_J in the final state. Using the large energy effective theory (LEET) techniques, we formulate B→KJ(∗)B \to K_J^{(*)} transition form factors in the large recoil region in terms of two independent LEET functions ζ⊄KJ(∗)\zeta_\perp^{K_J^{(*)}} and ζ∄KJ(∗)\zeta_\parallel^{K_J^{(*)}}, the values of which at zero momentum transfer are estimated in the BSW model. According to the QCD counting rules, ζ⊄,∄KJ(∗)\zeta_{\perp,\parallel}^{K_J^{(*)}} exhibit a dipole dependence in q2q^2. We predict the decay rates for B→KJ(∗)ÎłB \to K_J^{(*)} \gamma, B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- and B→KJ(∗)ΜΜˉB \to K_J^{(*)}\nu \bar{\nu}. The branching fractions for these decays with higher KK-resonances in the final state are suppressed due to the smaller phase spaces and the smaller values of ζ⊄,∄KJ(∗)\zeta^{K_J^{(*)}}_{\perp,\parallel}. Furthermore, if the spin of KJ(∗)K_J^{(*)} becomes larger, the branching fractions will be further suppressed due to the smaller Clebsch-Gordan coefficients defined by the polarization tensors of the KJ(∗)K_J^{(*)}. We also calculate the forward backward asymmetry of the B→KJ(∗)ℓ+ℓ−B \to K_J^{(*)} \ell^+ \ell^- decay, for which the zero is highly insensitive to the KK-resonances in the LEET parametrization.Comment: 27 pages, 4 figures, 7 tables;contents and figures corrected, title and references revise

    Terahertz Radar Cross Section Characterization using Laser Feedback Interferometry with a Quantum Cascade Laser

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    Radar cross section (RCS) measurements of complex, large objects are usually performed on scale models so that the measurement is carried out in a well-controlled environment. This letter explores the feasibility of RCS measurement using a terahertz quantum cascade laser via laser feedback interferometry. Numerical simulations show that the RCS information embedded in the non-linear interferometric signals obtained from simple targets can be retrieved through numerical fitting of the well-known excess phase equation. The method is validated experimentally using a terahertz quantum cascade laser and the results are well matched with those obtained from numerical simulations

    Acrylamide-forming potential of cereals, legumes and roots and tubers analyzed by UPLC-UV

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    For directing scientists, consumers, industry and stakeholders on mitigation strategies, there is a need to understand the acrylamide-forming potential of important Indian foods. Flour obtained from total 16 varieties of 9 Indian cereals, legumes and roots and tubers was heated at 160 °C for 20 min, acrylamide was extracted and quantified by UPLC-UV. Acrylamide level was above the European Commission indicative value in potato- and cereal-based food products, it ranged from 3436.13 to 5562.56 ÎŒg/kg in roots and tubers (potato and sweet potato). Among the cereals, maize (2195.31 ÎŒg/kg) and wheat (161.12 ÎŒg/kg) had the highest and lowest contents, respectively, whereas rice, sorghum and pearl millet showed intermediate values. Among the 2 legumes, soybean contained higher acrylamide (337.08–717.52 ÎŒg/kg) than chickpea (377.83–480.49 ÎŒg/kg). Analysis of variance revealed that roots and tubers acrylamide was highly significantly greater than the content in cereals (p < 0.0001) and in legumes (p < 0.0001) while there was no significant difference between cereals and legumes (p = 0.443). These results support the combination of pulses and minor cereals (chickpea, soybean, millets and sorghum) in cereal-based foods for improving the nutritional value and reducing acrylamide formation

    Efficacy and Safety of Nivolumab Plus Ipilimumab in Patients With Advanced Hepatocellular Carcinoma Previously Treated With Sorafenib The CheckMate 040 Randomized Clinical Trial

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    IMPORTANCE Most patients with hepatocellular carcinoma (HCC) are diagnosed with advanced disease not eligible for potentially curative therapies; therefore, new treatment options are needed. Combining nivolumab with ipilimumab may improve clinical outcomes compared with nivolumab monotherapy. OBJECTIVE To assess efficacy and safety of nivolumab plus ipilimumab in patients with advanced HCC who were previously treated with sorafenib. DESIGN, SETTING, AND PARTICIPANTS CheckMate 040 is a multicenter, open-label, multicohort, phase 1/2 study. In the nivolumab plus ipilimumab cohort, patients were randomized between January 4 and September 26, 2016. Treatment group information was blinded after randomization. Median follow-up was 30.7 months. Data cutoff for this analysis was January 2019. Patients were recruited at 31 centers in 10 countries/territories in Asia, Europe, and North America. Eligible patients had advanced HCC (with/without hepatitis B or C) previously treated with sorafenib. A total of 148 patients were randomized (50 to arm A and 49 each to arms B and C). INTERVENTIONS Patients were randomized 1:1:1 to either nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, administered every 3 weeks (4 doses), followed by nivolumab 240 mg every 2 weeks (arm A); nivolumab 3 mg/kg plus ipilimumab 1 mg/kg, administered every 3 weeks (4 doses), followed by nivolumab 240 mg every 2 weeks (arm B); or nivolumab 3 mg/kg every 2 weeks plus ipilimumab 1 mg/kg every 6 weeks (arm C). MAIN OUTCOMES AND MEASURES Coprimary end points were safety, tolerability, and objective response rate. Duration of response was also measured (investigator assessed with the Response Evaluation Criteria in Solid Tumors v1.1). RESULTS Of 148 total participants, 120 were male (81%). Median (IQR) age was 60 (52.5-66.5). At data cutoff (January 2019), the median follow-up was 30.7 months (IQR, 29.9-34.7). Investigator-assessed objective response rate was 32% (95% CI, 20%-47%) in arm A, 27% (95% CI, 15%-41%) in arm B, and 29% (95% CI, 17%-43%) in arm C. Median (range) duration of response was not reached (8.3-33.7+) in arm A and was 15.2 months (4.2-29.9+) in arm B and 21.7 months (2.8-32.7+) in arm C. Any-grade treatment-related adverse events were reported in 46 of 49 patients (94%) in arm A, 35 of 49 patients (71%) in arm B, and 38 of 48 patients (79%) in arm C; there was 1 treatment-related death (arm A; grade 5 pneumonitis). CONCLUSIONS AND RELEVANCE In this randomized clinical trial, nivolumab plus ipilimumab had manageable safety, promising objective response rate, and durable responses. The arm A regimen (4 doses nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks then nivolumab 240 mg every 2 weeks) received accelerated approval in the US based on the results of this study. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0165887

    Study of the temperature distribution in Si nanowires under microscopic laser beam excitation

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    The use of laser beams as excitation sources for the characterization of semiconductor nanowires (NWs) is largely extended. Raman spectroscopy and photoluminescence (PL) are currently applied to the study of NWs. However, NWs are systems with poor thermal conductivity and poor heat dissipation, which result in unintentional heating under the excitation with a focused laser beam with microscopic size, as those usually used in microRaman and microPL experiments. On the other hand, the NWs have subwavelength diameter, which changes the optical absorption with respect to the absorption in bulk materials. Furthermore, the NW diameter is smaller than the laser beam spot, which means that the optical power absorbed by the NW depends on its position inside the laser beam spot. A detailed analysis of the interaction between a microscopic focused laser beam and semiconductor NWs is necessary for the understanding of the experiments involving laser beam excitation of NWs. We present in this work a numerical analysis of the thermal transport in Si NWs, where the heat source is the laser energy locally absorbed by the NW. This analysis takes account of the optical absorption, the thermal conductivity, the dimensions, diameter and length of the NWs, and the immersion medium. Both free standing and heat-sunk NWs are considered. Also, the temperature distribution in ensembles of NWs is discussed. This analysis intends to constitute a tool for the understanding of the thermal phenomena induced by laser beams in semiconductor NWs

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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