3,515 research outputs found

    Genetic incorporation of D-Lysine into diketoreductase in Escherichia coli cells

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    D-Lysine has been genetically introduced into diketoreductase in E. coli cells by utilization of an orthogonal Ph tRNA /Lysyl-tRNA synthetase pair. This is the first report on the genetic incoporation of D-amino acids into proteins, which may be generally applicable to a wide variety of applications

    Branching Fractions and CP Asymmetries of the Quasi-Two-Body Decays in BsK0(K0)K±πB_{s} \to K^0(\overline K^0)K^\pm \pi^\mp within PQCD Approach

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    Motivated by the first untagged decay-time-integrated amplitude analysis of BsKSKπ±B_s \to K_SK^{\mp}\pi^{\pm} decays performed by LHCb collaboration, where the decay amplitudes are modeled to contain the resonant contributions from intermediate resonances K(892)K^*(892), K0(1430)K_0^*(1430) and K2(1430)K_2^*(1430), we comprehensively investigate the quasi-two-body BsK0/K0K±πB_{s} \to K^0/\overline{\kern -0.2em K}^0 K^{\pm}\pi^{\mp} decays, and calculate the branching fractions and the time-dependent CPCP asymmetries within the perturbative QCD approach based on the kTk_T factorization. In the quasi-two-body space region the calculated branching fractions with the considered intermediate resonances are in good agreement with the experimental results of LHCb by adopting proper KπK\pi pair wave function, describing the interaction between the kaon and pion in the KπK\pi pair. Furthermore,within the obtained branching fractions of the quasi-two-body decays, we also calculate the branching fractions of corresponding two-body decays, and the results consist with the LHCb measurements and the earlier studies with errors. For these considered decays, since the final states are not flavour-specific, the time-dependent CPCP could be measured. We calculate six CPCP-violation observables, which can be tested in the ongoing LHCb experiment.Comment: 20 page

    Cabibbo-Kobayashi-Maskawa-favored BB decays to a scalar meson and a DD meson

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    Within the perturbative QCD approach, we investigated the Cabibbo-Kobayashi-Maskawa-favored BDSB \to \overline{D} S ("SS" denoting the scalar meson) decays on the basis of the two-quark picture. Supposing the scalar mesons are the ground states or the first excited states, we calculated the the branching ratios of 72 decay modes. Most of the branching ratios are in the range 10410^{-4} to 10710^{-7}, which can be tested in the ongoing LHCb experiment and the forthcoming Belle-II experiment. Some decays, such as B+D()0a0+(980/1450)B^+ \to \overline{D}^{(*)0} a_0^+(980/1450) and B+D()a0+(980/1450)B^+ \to D^{(*)-} a_0^+(980/1450), could be used to probe the inner structure and the character of the scalar mesons, if the experiments are available. In addition, the ratios between the Br(B0D()0σ)Br(B^0\to \overline{D}^{(*)0}\sigma) and Br(B0D()0f0(980))Br(B^0\to \overline{D}^{(*)0}f_0(980)) provide a potential way to determine the mixing angle between σ\sigma and f0(980)f_0(980). Moreover, since in the standard model these decays occur only through tree operators and have no CPCP asymmetries, any deviation will be signal of the new physics beyond the standard model.Comment: 2 figures, 6 table

    Simultaneous observation of small- and large-energy-transfer electron-electron scattering in three dimensional indium oxide thick films

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    In three dimensional (3D) disordered metals, the electron-phonon (\emph{e}-ph) scattering is the sole significant inelastic process. Thus the theoretical predication concerning the electron-electron (\emph{e}-\emph{e}) scattering rate 1/τφ1/\tau_\varphi as a function of temperature TT in 3D disordered metal has not been fully tested thus far, though it was proposed 40 years ago [A. Schmid, Z. Phys. \textbf{271}, 251 (1974)]. We report here the simultaneous observation of small- and large-energy-transfer \emph{e}-\emph{e} scattering in 3D indium oxide thick films. In temperature region of T100T\gtrsim100\,K, the temperature dependence of resistivities curves of the films obey Bloch-Gr\"{u}neisen law, indicating the films possess degenerate semiconductor characteristics in electrical transport property. In the low temperature regime, 1/τφ1/\tau_\varphi as a function of TT for each film can not be ascribed to \emph{e}-ph scattering. To quantitatively describe the temperature behavior of 1/τφ1/\tau_\varphi, both the 3D small- and large-energy-transfer \emph{e}-\emph{e} scattering processes should be considered (The small- and large-energy-transfer \emph{e}-\emph{e} scattering rates are proportional to T3/2T^{3/2} and T2T^2, respectively). In addition, the experimental prefactors of T3/2T^{3/2} and T2T^{2} are proportional to kF5/23/2k_F^{-5/2}\ell^{-3/2} and EF1E_F^{-1} (kFk_F is the Fermi wave number, \ell is the electron elastic mean free path, and EFE_F is the Fermi energy), respectively, which are completely consistent with the theoretical predications. Our experimental results fully demonstrate the validity of theoretical predications concerning both small- and large-energy-transfer \emph{e}-\emph{e} scattering rates.Comment: 5 pages and 4 figure
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