309 research outputs found

    Adefovir Dipivoxil for the Treatment of Hepatitis B e Antigen–Positive Chronic Hepatitis B

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    BACKGROUND In preclinical and phase 2 studies, adefovir dipivoxil demonstrated potent activity against hepatitis B virus (HBV), including lamivudine-resistant strains. METHODS We randomly assigned 515 patients with chronic hepatitis B who were positive for hepatitis B e antigen (HBeAg) to receive 10 mg of adefovir dipivoxil (172 patients), 30 mg of adefovir dipivoxil (173), or placebo (170) daily for 48 weeks. The primary end point was histologic improvement in the 10-mg group as compared with the placebo group. RESULTS After 48 weeks of treatment, significantly more patients who received 10 mg or 30 mg of adefovir dipivoxil per day than who received placebo had histologic improvement (53 percent [P CONCLUSIONS In patients with HBeAg-positive chronic hepatitis B, 48 weeks of 10 mg or 30 mg of adefovir dipivoxil per day resulted in histologic liver improvement, reduced serum HBV DNA and alanine aminotransferase levels, and increased the rates of HBeAg seroconversion. The 10-mg dose has a favorable risk–benefit profile for long-term treatment. No adefovir-associated resistance mutations were identified in the HBV DNA polymerase gene

    Optimal States for Bell inequality Violations using Quadrature Phase Homodyne Measurements

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    We identify what ideal correlated photon number states are to required to maximize the discrepancy between local realism and quantum mechanics when a quadrature homodyne phase measurement is used. Various Bell inequality tests are considered.Comment: 6 pages, 5 Figure

    Nonlinear optics via double dark resonances

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    Double dark resonances originate from a coherent perturbation of a system displaying electromagnetically induced transparency. We experimentally show and theoretically confirm that this leads to the possibility of extremely sharp resonances prevailing even in the presence of considerable Doppler broadening. A gas of 87Rb atoms is subjected to a strong drive laser and a weak probe laser and a radio frequency field, where the magnetic coupling between the Zeeman levels leads to nonlinear generation of a comb of sidebands.Comment: 6 pages, 9 figure

    Observers and Locality in Everett Quantum Field Theory

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    A model for measurement in collapse-free nonrelativistic fermionic quantum field theory is presented. In addition to local propagation and effectively-local interactions, the model incorporates explicit representations of localized observers, thus extending an earlier model of entanglement generation in Everett quantum field theory [M. A. Rubin, Found. Phys. 32, 1495-1523 (2002)]. Transformations of the field operators from the Heisenberg picture to the Deutsch-Hayden picture, involving fictitious auxiliary fields, establish the locality of the model. The model is applied to manifestly-local calculations of the results of measurements, using a type of sudden approximation and in the limit of massive systems in narrow-wavepacket states. Detection of the presence of a spin-1/2 system in a given spin state by a freely-moving two-state observer illustrates the features of the model and the nonperturbative computational methodology. With the help of perturbation theory the model is applied to a calculation of the quintessential "nonlocal" quantum phenomenon, spin correlations in the Einstein-Podolsky-Rosen-Bohm experiment.Comment: Some changes to introduction and discussion sections, typos corrected, conclusions unchanged. To appear in Foundations of Physic

    Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider

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    This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-→e+e- and (for the ϒ(4S) only) e+e-→μ+μ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-→e+e- and e+e-→μ+μ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the ϒ(3S) and ϒ(2S) resonances, an additional uncertainty arises due to ϒ→e+e-X background. For data collected off the ϒ resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the ϒ(4S), 0.58% (0.72%) for the ϒ(3S), and 0.68% (0.88%) for the ϒ(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l’Energie Atomique and Institut National de Physique Nucléaire et de Physiquedes Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e Innovación (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Recombinant expression of Aryl Hydrocarbon Receptor for quantitative ligand-binding analysis

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    Recombinant expression of the Aryl Hydrocarbon Receptor (AhR) yields small amounts of ligand-binding competent AhR. Therefore, Spodoptera frugiperda (Sf9) cells and baculovirushave been evaluated for high level and functional expression of AhR. Rat and human AhR wereexpressed as soluble protein in significant amounts. Expression of ligand-binding competentAhR was sensitive to the protein concentration of Sf9 extract, and co-expression of the chaperonep23 failed to affect the yield of functional ligand-binding AhR. The expression systemyielded high levels of functional protein, with the ligand-binding capacity (Bmax) typically 20-fold higher than that obtained with rat liver cytosol. Quantitative estimates of the ligand-bindingaffinity of human and rat AhR were obtained; the Kd for recombinant rat AhR was indistinguishablefrom that of native rat AhR, thereby validating the expression system as a faithfulmodel for native AhR. The human AhR bound TCDD with significantly lower affinity than therat AhR. These findings demonstrate high-level expression of ligand-binding competent AhR,and sufficient AhR for quantitative analysis of ligand-binding

    Observation of the baryonic decay B \uaf 0 \u2192 \u39bc+ p \uaf K-K+

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    We report the observation of the baryonic decay B\uaf0\u2192\u39bc+p\uafK-K+ using a data sample of 471 7106 BB\uaf pairs produced in e+e- annihilations at s=10.58GeV. This data sample was recorded with the BABAR detector at the PEP-II storage ring at SLAC. We find B(B\uaf0\u2192\u39bc+p\uafK-K+)=(2.5\ub10.4(stat)\ub10.2(syst)\ub10.6B(\u39bc+)) 710-5, where the uncertainties are statistical, systematic, and due to the uncertainty of the \u39bc+\u2192pK-\u3c0+ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay B\uaf0\u2192\u39bc+p\uaf\u3c6, we determine the upper limit B(B\uaf0\u2192\u39bc+p\uaf\u3c6)<1.2 710-5 at 90% confidence level
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