503 research outputs found

    Functional characterization of GABAA receptor-mediated modulation of cortical neuron network activity in microelectrode array recordings

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    The numerous γ-aminobutyric acid type A receptor (GABAAR) subtypes are differentially expressed and mediate distinct functions at neuronal level. In this study we have investigated GABAAR-mediated modulation of the spontaneous activity patterns of primary neuronal networks from murine frontal cortex by characterizing the effects induced by a wide selection of pharmacological tools at a plethora of activity parameters in microelectrode array (MEA) recordings. The basic characteristics of the primary cortical neurons used in the recordings were studied in some detail, and the expression levels of various GABAAR subunits were investigated by western blotting and RT-qPCR. In the MEA recordings, the pan-GABAAR agonist muscimol and the GABABR agonist baclofen were observed to mediate phenotypically distinct changes in cortical network activity. Selective augmentation of αβγ GABAAR signaling by diazepam and of δ-containing GABAAR (δ-GABAAR) signaling by DS1 produced pronounced changes in the majority of the activity parameters, both drugs mediating similar patterns of activity changes as muscimol. The apparent importance of δ-GABAAR signaling for network activity was largely corroborated by the effects induced by the functionally selective δ-GABAAR agonists THIP and Thio-THIP, whereas the δ-GABAAR selective potentiator DS2 only mediated modest effects on network activity, even when co-applied with low THIP concentrations. Interestingly, diazepam exhibited dramatically right-shifted concentration-response relationships at many of the activity parameters when co-applied with a trace concentration of DS1 compared to when applied alone. In contrast, the potencies and efficacies displayed by DS1 at the networks were not substantially altered by the concomitant presence of diazepam. In conclusion, the holistic nature of the information extractable from the MEA recordings offers interesting insights into the contributions of various GABAAR subtypes/subgroups to cortical network activity and the putative functional interplay between these receptors in these neurons

    Search for B+ -> l+ nu gamma decays with hadronic tagging using the full Belle data sample

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    We search for the decay B+ -> l+ nu gamma with l+ = e+ or mu+ using the full Belle data set of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one B meson in a hadronic decay mode and search for the B+ -> l+ nu gamma decay in the remainder of the event. We observe no significant signal within the phase space of E_gamma^sig > 1 GeV and obtain upper limits of BR(B+ -> e+ nu gamma) mu+ nu gamma) l+ nu gamma) < 3.5 x 10^-6 at 90 % credibility level.Comment: Submitted to Phys. Rev.

    Measurements of the masses and widths of the Σc(2455)0/++\Sigma_{c}(2455)^{0/++} and Σc(2520)0/++\Sigma_{c}(2520)^{0/++} baryons

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    We present measurements of the masses and decay widths of the baryonic states Σc(2455)0/++\Sigma_{c}(2455)^{0/++} and Σc(2520)0/++\Sigma_{c}(2520)^{0/++} using a data sample corresponding to an integrated luminosity of 711 fb1^{-1} collected with the Belle detector at the KEKB e+ee^{+}e^{-} asymmetric-energy collider operating at the Υ(4S)\Upsilon(4S) resonance. We report the mass differences with respect to the Λc+\Lambda_{c}^{+} baryon M(Σc(2455)0)M(Λc+)=167.29±0.01±0.02M(\Sigma_{c}(2455)^{0})-M(\Lambda_{c}^{+}) = 167.29\pm0.01\pm0.02 MeV/c2c^{2}, M(Σc(2455)++)M(Λc+)=167.51±0.01±0.02M(\Sigma_{c}(2455)^{++})-M(\Lambda_{c}^{+}) = 167.51\pm0.01\pm0.02 MeV/c2c^{2}, M(Σc(2520)0)M(Λc+)=231.98±0.11±0.04M(\Sigma_{c}(2520)^{0})-M(\Lambda_{c}^{+}) = 231.98\pm0.11\pm0.04 MeV/c2c^{2}, M(Σc(2520)++)M(Λc+)=231.99±0.10±0.02M(\Sigma_{c}(2520)^{++})-M(\Lambda_{c}^{+}) = 231.99\pm0.10\pm0.02 MeV/c2c^{2}, and the decay widths Γ(Σc(2455)0)=1.76±0.040.21+0.09\Gamma(\Sigma_{c}(2455)^{0}) = 1.76\pm0.04^{+0.09}_{-0.21} MeV/c2c^{2}, Γ(Σc(2455)++)=1.84±0.040.20+0.07\Gamma(\Sigma_{c}(2455)^{++}) = 1.84\pm0.04^{+0.07}_{-0.20} MeV/c2c^{2}, Γ(Σc(2520)0)=15.41±0.410.32+0.20\Gamma(\Sigma_{c}(2520)^{0}) = 15.41\pm0.41^{+0.20}_{-0.32} MeV/c2c^{2}, Γ(Σc(2520)++)=14.77±0.250.30+0.18\Gamma(\Sigma_{c}(2520)^{++}) = 14.77\pm0.25^{+0.18}_{-0.30} MeV/c2c^{2}, where the first uncertainties are statistical and the second are systematic. The isospin mass splittings are measured to be M(Σc(2455)++)M(Σc(2455)0)=0.22±0.01±0.01M(\Sigma_{c}(2455)^{++})-M(\Sigma_{c}(2455)^{0})=0.22\pm0.01\pm0.01 MeV/c2c^{2} and M(Σc(2520)++)M(Σc(2520)0)=0.01±0.15±0.03M(\Sigma_{c}(2520)^{++})-M(\Sigma_{c}(2520)^{0})=0.01\pm0.15\pm0.03 MeV/c2c^{2}. These results are the most precise to date.Comment: 13 pages, 4 figures, Submitted to PRD(RC

    Measurement of e+eγχcJe^+e^- \to \gamma\chi_{cJ} via initial state radiation at Belle

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    The process e+eγχcJe^+e^- \to \gamma\chi_{cJ} (JJ=1, 2) is studied via initial state radiation using 980 fb1^{-1} of data at and around the Υ(nS)\Upsilon(nS) (nn=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. No significant signal is observed except from ψ(2S)\psi(2S) decays. Upper limits on the cross sections between s=3.80\sqrt{s}=3.80 and 5.56 GeV5.56~{\rm GeV} are determined at the 90% credibility level, which range from few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [ψ(4040\psi(4040), ψ(4160)\psi(4160), and ψ(4415)\psi(4415)] and charmoniumlike [Y(4260)Y(4260), Y(4360)Y(4360), and Y(4660)Y(4660)] states to γχcJ\gamma\chi_{cJ}.Comment: Accepted by PR

    First observation of the hadronic transition Υ(4S)ηhb(1P) \Upsilon(4S) \to \eta h_{b}(1P) and new measurement of the hb(1P)h_b(1P) and ηb(1S)\eta_b(1S) parameters

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    Using a sample of 771.6×106771.6 \times 10^{6} Υ(4S)\Upsilon(4S) decays collected by the Belle experiment at the KEKB e+ee^+e^- collider, we observe for the first time the transition Υ(4S)ηhb(1P)\Upsilon(4S) \to \eta h_b(1P) with the branching fraction B[Υ(4S)ηhb(1P)]=(2.18±0.11±0.18)×103{\cal B}[\Upsilon(4S) \to \eta h_b(1P)]= (2.18 \pm 0.11 \pm 0.18) \times 10^{-3} and we measure the hb(1P)h_b(1P) mass Mhb(1P)=(9899.3±0.4±1.0)M_{h_{b}(1P)} = (9899.3 \pm 0.4 \pm 1.0) MeV/c2c^{2}, corresponding to the hyperfine splitting ΔMHF(1P)=(0.6±0.4±1.0)\Delta M_{\mathrm HF}(1P) = (0.6 \pm 0.4 \pm 1.0) MeV/c2c^{2}. Using the transition hb(1P)γηb(1S)h_b(1P) \to \gamma \eta_b(1S), we measure the ηb(1S)\eta_b(1S) mass Mηb(1S)=(9400.7±1.7±1.6)M_{\eta_{b}(1S)} = (9400.7 \pm 1.7 \pm 1.6) MeV/c2c^{2}, corresponding to ΔMHF(1S)=(59.6±1.7±1.6)\Delta M_{\mathrm HF}(1S) = (59.6 \pm 1.7 \pm 1.6) MeV/c2c^{2}, the ηb(1S)\eta_b(1S) width Γηb(1S)=(85+6±5)\Gamma_{\eta_{b}(1S)} = (8 ^{+6}_{-5} \pm 5) MeV/c2c^{2} and the branching fraction B[hb(1P)γηb(1S)]=(56±8±4)%{\cal B}[h_b(1P) \to \gamma \eta_b(1S)]= (56 \pm 8 \pm 4) \%.Comment: 7 pages, 2 figures, submitted to Phys. Rev. Let

    Search for CP violation in D^0 -> pi^0 pi^0 decays

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    We search for CP violation in neutral charm meson decays using a data sample with an integrated luminosity of 966 fb^-1 collected with the Belle detector at the KEKB e+e- asymmetric-energy collider. The asymmetry obtained in the rate of D^0 and D^0-bar decays to the pi^0 pi^0 final state, [-0.03+-0.64(stat)+-0.10(syst)]%, is consistent with no CP violation. This constitutes an order of magnitude improvement over the existing result. We also present an updated measurement of the CP asymmetry in the D^0 -> K_S pi^0 decay: A_{CP}(D^0 -> K_S pi^0) = [-0.21+-0.16(stat)+-0.07(syst)]%

    Observation of a new charged charmoniumlike state in B -> J/psi K pi decays

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    We present the results of an amplitude analysis of anti-B0 -> J/psi K- pi+ decays. A new charged charmoniumlike state Zc(4200)+ decaying to J/psi pi+ is observed with a significance of 6.2 sigma. The mass and width of the Zc(4200)+ are 4196 +31-29 +17-13 MeV/c^2 and 370 +70-70 +70-132 MeV, respectively; the preferred assignment of the quantum numbers is J^P = 1^+. In addition, we find evidence for Zc(4430)+ -> J/psi pi+. The analysis is based on a 711 fb^-1 data sample collected by the Belle detector at the asymmetric-energy e+ e- collider KEKB.Comment: 14 pages, 13 figure

    Measurements of the Υ(10860)\Upsilon(10860) and Υ(11020)\Upsilon(11020) resonances via σ(e+eΥ(nS)π+π)\sigma(e^+e^-\rightarrow\Upsilon(n{\rm S})\pi^+\pi^-)

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    We report new measurements of the total cross sections for e+eΥ(nS)π+πe^+e^-\to \Upsilon(n{\rm S})\pi^+\pi^- (nn = 1, 2, 3) and e+ebbˉe^+e^-\to b\bar b from a high-luminosity fine scan of the region s=10.63\sqrt{s} = 10.63-11.0511.05 GeV with the Belle detector. We observe that the Υ(nS)π+π\Upsilon(n{\rm S})\pi^+\pi^- spectra have little or no non-resonant component and extract from them the masses and widths of Υ(10860)\Upsilon(10860) and Υ(11020)\Upsilon(11020) and their relative phase. We find M10860=(10891.1±3.21.7+0.6)M_{10860}=(10891.1\pm3.2^{+0.6}_{-1.7}) MeV/c2c^2 and \Gamma_{10860}=(53.7^{+7.1}_{-5.6}\,^{+1.3}_{-5.4}) MeV and report first measurements M_{11020}=(10987.5^{+6.4}_{-2.5}\,^{+9.0}_{-2.1}) MeV/c2c^2, \Gamma_{11020}=(61^{+9}_{-19}\,^{+2}_{-20}) MeV, and \phi_{\rm 11020}-\phi_{\rm 10860} = (-1.0\pm0.4\,^{+1.4}_{-0.1}) rad.Comment: University of Cincinnati preprint UCHEP-15-01, submitted to Physical Review D - Rapid Communication

    Observation of D0Dˉ0D^0-\bar{D}^0 Mixing in e+ee^+e^- Collisions

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    We observe D0Dˉ0D^0-\bar{D}^0 mixing in the decay D0K+πD^0\rightarrow K^+\pi^- using a data sample of integrated luminosity 976 fb1^{-1} collected with the Belle detector at the KEKB e+ee^+e^- asymmetric-energy collider. We measure the mixing parameters x2=(0.09±0.22)×103{x'}^2 = (0.09\pm0.22)\times 10^{-3} and y=(4.6±3.4)×103y' = (4.6\pm3.4)\times 10^{-3} and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates RD=(3.53±0.13)×103R_D = (3.53\pm0.13)\times 10^{-3}, where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.Comment: 6 pages, 4 figure
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