239 research outputs found

    Agonist-mediated switching of ion selectivity in TPC2 differentially promotes lysosomal function

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    Ion selectivity is a defining feature of a given ion channel and is considered immutable. Here we show that ion selectivity of the lysosomal ion channel TPC2, which is hotly debated (Calcraft et al., 2009; Guo et al., 2017; Jha et al., 2014; Ruas et al., 2015; Wang et al., 2012), depends on the activating ligand. A high-throughput screen identified two structurally distinct TPC2 agonists. One of these evoked robust Ca2+-signals and non-selective cation currents, the other weaker Ca2+-signals and Na+-selective currents. These properties were mirrored by the Ca2+-mobilizing messenger, NAADP and the phosphoinositide, PI(3,5)P2, respectively. Agonist action was differentially inhibited by mutation of a single TPC2 residue and coupled to opposing changes in lysosomal pH and exocytosis. Our findings resolve conflicting reports on the permeability and gating properties of TPC2 and they establish a new paradigm whereby a single ion channel mediates distinct, functionally-relevant ionic signatures on demand

    Measurement of the Inclusive Semi-electronic D0D^0 Branching Fraction

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    Using the angular correlation between the π+\pi^+ emitted in a D+D0π+D^{*+} \rightarrow D^0 \pi^+ decay and the e+e^+ emitted in the subsequent D0Xe+νD^0 \rightarrow Xe^+\nu decay, we have measured the branching fraction for the inclusive semi-electronic decay of the D0D^0 meson to be: {\cal B}(D^0 \rightarrow X e^+ \nu) = [6.64 \pm 0.18 (stat.) \pm 0.29 (syst.)] \%. The result is based on 1.7 fb1^{-1} of e+ee^+e^- collisions recorded by the CLEO II detector located at the Cornell Electron Storage Ring (CESR). Combining the analysis presented in this paper with previous CLEO results we find, \frac{{\cal B} (D^0 \rightarrow X e^+ \nu)} {{\cal B} (D^0 \rightarrow K^- \pi^+)} = 1.684 \pm 0.056 (stat.) \pm 0.093(syst.) and \frac{{\cal B}(D\rightarrow K^-e^+\nu)} {{\cal B}(D\rightarrow Xe^+\nu)} = 0.581 \pm 0.023 (stat.) \pm 0.028(syst.). The difference between the inclusive rate and the sum of the measured exclusive branching fractions (measured at CLEO and other experiments) is (3.3±7.2)%(3.3 \pm 7.2) \% of the inclusive rate.Comment: Latex file, 33pages, 4 figures Submitted to PR

    Measurements of the Ratios B(Ds+η+ν)/B(Ds+ϕ+ν){\cal B}(D_s^+\to \eta\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu) and B(Ds+η+ν)/B(Ds+ϕ+ν){\cal B}(D_s^+\to \eta'\ell^+\nu)/{\cal B}(D_s^+\to \phi\ell^+\nu)

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    Using the CLEO~II detector we measure B(Ds+ηe+ν)/B(Ds+ϕe+ν)=1.24±0.12±0.15{\cal B}(D_s^+\to \eta e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =1.24\pm0.12\pm0.15, B(Ds+ηe+ν)/B(Ds+ϕe+ν)=0.43±0.11±0.07{\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \phi e^+\nu) =0.43\pm0.11\pm0.07 and B(Ds+ηe+ν)/B(Ds+ηe+ν)=0.35±0.09±0.07{\cal B}(D_s^+\to \eta' e^+\nu)/{\cal B}(D_s^+\to \eta e^+\nu) =0.35\pm0.09\pm0.07. We find the vector to pseudoscalar ratio, B(Ds+ϕe+ν)/B(Ds+(η+η)e+ν)=0.60±0.06±0.06{\cal B}(D_s^+\to \phi e^+\nu)/{\cal B}(D_s^+\to (\eta+\eta') e^+\nu) =0.60\pm0.06\pm0.06, which is similar to the ratio found in non strange DD decays.Comment: 11 page uuencoded postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay

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    Using the CLEO II detector at the e+ee^+e^- storage ring CESR, we have determined the Michel parameters ρ\rho, ξ\xi, and δ\delta in τlννˉ\tau^\mp \to l^\mp\nu\bar{\nu} decay as well as the tau neutrino helicity parameter hντh_{\nu_\tau} in τππ0ν\tau^\mp \to \pi^\mp\pi^0\nu decay. From a data sample of 3.02×1063.02\times 10^6 tau pairs produced at s=10.6GeV\sqrt{s}=10.6 GeV, using events of the topology e+eτ+τ(l±ννˉ)(ππ0ν)e^+e^- \to \tau^+\tau^- \to (l^\pm\nu\bar{\nu}) (\pi^\mp\pi^0\nu) and e+eτ+τ(π±π0νˉ)(ππ0ν)e^+e^- \to \tau^+\tau^- \to (\pi^\pm\pi^0\bar{\nu}) (\pi^\mp\pi^0\nu), and the determined sign of hντh_{\nu_\tau}, the combined result of the three samples is: ρ=0.747±0.010±0.006\rho = 0.747\pm 0.010\pm 0.006, ξ=1.007±0.040±0.015\xi = 1.007\pm 0.040\pm 0.015, ξδ=0.745±0.026±0.009\xi\delta = 0.745\pm 0.026\pm 0.009, and hντ=0.995±0.010±0.003h_{\nu_\tau} = -0.995\pm 0.010\pm 0.003. The results are in agreement with the Standard Model V-A interaction.Comment: 18 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of the Branching Ratios for the Decays of Ds+ηπ+,ηπ+,ηρ+D_{s}^{+}\to \eta\pi^{+}, \eta^{'}\pi^{+}, \eta\rho^{+}, and etaρ+eta^{'}\rho^{+}

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    Using a data sample with integrated luminosity of about 3.9 fb^{-1} collected in e+ e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds -> (eta, eta') pi and Ds -> (eta, eta') rho relative to Ds -> phi pi. These decay modes are among the most common hadronic decays of the Ds's and can be related by factorization to the semileptonic decays Ds -> (eta,eta') l nu. The results obtained are compared with previous CLEO results and with the branching ratios measured for the related semileptonic decays. We also report results on the Cabibbo-suppressed decays of the D+ to the same final states.Comment: 18 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of the BˉDνˉ\bar{B}\to D\ell\bar{\nu} Partila Width and Form Factor Parameters

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    We have studied the decay BˉDνˉ\bar{B} \to D\ell\bar{\nu}, where =eorμ\ell=e or \mu. From a fit to the differential decay rate dΓ/dwd\Gamma/dw we measure the rate normalization FD(1)Vcb{\cal F}_D(1)|V_{cb}| and form factor slope ρ^D2\hat{\rho}^2_D, and, using measured values of τB\tau_B, find Γ(BˉDνˉ)=(12.0±0.9±2.1)ns1\Gamma(\bar{B} \to D\ell\bar{\nu}) = (12.0 \pm 0.9 \pm 2.1) ns^{-1}. The resulting branching fractions are B(Bˉ0D+νˉ)=(1.87±0.15±0.32){\cal B}(\bar{B}^0 \to D^+\ell^-\bar{\nu})=(1.87 \pm 0.15 \pm 0.32)% and B(BD0νˉ)=(1.94±0.15±0.34){\cal B}(B^- \to D^0\ell^-\bar{\nu})=(1.94 \pm 0.15 \pm 0.34)%. The form factor parameters are in agreement with those measured in BˉDνˉ\bar{B} \to D^*\ell\bar{\nu} decays, as predicted by heavy quark effective theory.Comment: 11 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Tau Neutrino Helicity from h±h^{\pm} Energy Correlations

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    We report a measurement of the magnitude of the tau neutrino helicity from tau-pair events taken with the CLEO detector at the CESR electron-positron storage ring. Events in which each tau undergoes the decay tau -> h nu, with h a charged pion or kaon, are analyzed for energy correlations between the daughter hadrons, yielding |xi| = 2*|h_nu| = 1.03 +/- 0.06 +/- 0.04, with the first error statistical and the second systematic.Comment: 11 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Limit on the Two-Photon Production of the Glueball Candidate fJ(2220)f_{J}(2220) at CLEO

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    We use the CLEO detector at the Cornell electron-positron storage ring, CESR, to search for the two-photon production of the glueball candidate f_J(2220) in its decay to K_s K_s. We present a restrictive upper limit on the product of the two-photon partial width and the K_s K_s branching fraction. We use this limit to calculate a lower limit on the stickiness, which is a measure of the two-gluon coupling relative to the two-photon coupling. This limit on stickiness indicates that the f_J(2220) has substantial glueball content.Comment: 9 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Search for Exclusive Charmless Hadronic B Decays

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    We have searched for two-body charmless hadronic decays of BB mesons. Final states include ππ\pi\pi, KπK \pi, and KKKK with both charged and neutral kaons and pions; πρ\pi\rho, KρK \rho, and KπK^*\pi; and KϕK\phi, Kϕ K^*\phi, and ϕϕ\phi\phi. The data used in this analysis consist of 2.6~million BBˉB\bar{B}~pairs produced at the Υ(4S)\Upsilon(4S) taken with the CLEO-II detector at the Cornell Electron Storage Ring (CESR). We measure the branching fraction of the sum of B0π+πB^0 \rightarrow \pi^+\pi^- and B0K+πB^0 \rightarrow K^+\pi^- to be (1.80.50.3+0.6+0.2±0.2)×105(1.8^{+0.6+0.2}_{-0.5-0.3}\pm0.2) \times 10^{-5}. In addition, we place upper limits on individual branching fractions in the range from 10410^{-4} to 10610^{-6}.Comment: 33 page LATEX file, uses REVTEX and psfig, 14 figures in a separate uuencoded postscript file, postscript version also available through http://w4.lns.cornell.edu/public/CLN

    Study of Gluon versus Quark Fragmentation in Υggγ\Upsilon\to gg\gamma and e+eqqˉγe^{+}e^{-}\to q\bar{q}\gamma Events at \sqrt{s}=10 GeV

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    Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for jet-jet masses less than 7 GeV.Comment: 15 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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