681 research outputs found

    A New Photosensory Function for Simple Photoreceptors, the Intrinsically Photoresponsive Neurons of the Sea Slug Onchidium

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    Simple photoreceptors, namely intrinsically light-sensitive neurons without microvilli and/or cilia, have long been known to exist in the central ganglia of crayfish, Aplysia, Onchidium, and Helix. These simple photoreceptors are not only first-order photosensory cells, but also second-order neurons (interneurons), relaying several kinds of sensory synaptic inputs. Another important issue is that the photoresponses of these simple photoreceptors show very slow kinetics and little adaptation. These characteristics suggest that the simple photoreceptors of the Onchidium have a function in non-image-forming vision, different from classical eye photoreceptors used for cording dynamic images of vision. The cited literature provides evidence that the depolarizing and hyperpolarizing photoresponses of simple photoreceptors play a role in the long-lasting potentiation of synaptic transmission of excitatory and inhibitory sensory inputs, and as well as in the potentiation and the suppression of the subsequent behavioral outputs. In short, we suggest that simple photoreceptors operate in the general potentiation of synaptic transmission and subsequent motor output; i.e., they perform a new photosensory function

    Anion channel sensitivity to cytosolic organic acids implicates a central role for oxaloacetate in integrating ion flux with metabolism in stomatal guard cells

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    Stomatal guard cells play a key role in gas exchange for photosynthesis and in minimizing transpirational water loss from plants by opening and closing the stomatal pore. The bulk of the osmotic content driving stomatal movements depends on ionic fluxes across both the plasma membrane and tonoplast, the metabolism of organic acids, primarily Mal (Imitate), and its accumulation and loss. Anion channels at the plasma membrane are thought to comprise a major pathway for Mal efflux during stomatal closure, implicating their key role in linking solute flux with metabolism. Nonetheless, little is known of the regulation of anion channel current (I(Cl)) by cytosolic Mal or its immediate metabolite OAA (oxaloacetate). In the present study, we have examined the impact of Mal, OAA and of the monocarboxylic acid anion acetate in guard cells of Vicia faba L. and report that all three organic acids affect I(Cl), but with markedly different characteristics and sidedness to their activities. Most prominent was a suppression of I(Cl) by OAA within the physiological range of concentrations found in vivo. These findings indicate a capacity for OAA to co-ordinate organic acid metabolism with I(Cl), through the direct effect of organic acid pool size. The findings of the present study also add perspective to in vivo recordings using acetate-based electrolytes

    Observation of chi_c2 Production in B-meson Decay

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    We report the first observation of chi_c2 production in B-meson decays. We find an inclusive B -> chi_c2 X branching fraction of (1.80^{+0.23}_{-0.28}+/- 0.26) 10^-3. The data set, collected with the Belle detector at the KEKB e^+e^- collider, consists of 31.9 million B\bar B events. We also present branching fractions and momentum spectra for both chi_c1 and chi_c2 production.Comment: 5 pages with 2 figure

    Measurement of B0d - B0d-bar mixing rate from the time evolution of dilepton events at the Upsilon(4S)

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    We report a determination of the B0d - B0d-bar mixing parameter Delta-m_d based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 /fb data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Delta-m_d as a free parameter. Using both muons and electrons, we obtain Delta-m_d = 0.463 +- 0.008(stat.) +- 0.016(sys.) ps^{-1} This is the first determination of Delta-m_d from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.Comment: 12 pages, 2 figure

    Resveratrol and Red Wine Improve Healthspan

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    レスベラトロールはブドウの果皮に多いポリフェノールで、 ブドウを丸ごと使用して作られる赤ワインにも多い。 レスベラトロールは寿命を延ばす遺伝子(サーチュイン)を活性化し、 さらに細胞のエネルギーが減少するとミトコンドリアを活性化するAMPKも活性化、 また細胞の古くなった小器官や成分を分解し細胞内を浄化するオートファジーも活性化させる。 レスベラトロールにより、 酵母や無脊椎動物では寿命が延び、 マウスではインスリン抵抗性や動脈硬化に関連する加齢性徴候が改善される。 また、 適量飲酒の作用として、 血小板の凝集抑制、 HDLコレステロールの増加、 血糖値の低下などがあり、 飲酒そのものにも心筋梗塞や糖尿病の予防効果がみられる。 これらの作用はレスベラトロールにもある。 レスベラトロールは脂溶性物質でアルコールと共に摂取すると体内に吸収されやすい。 赤ワインでのレスベラトロールとアルコールの相乗効果により健康寿命を延ばすことが期待される。Resveratrol is a polyphenol present in grape skin and found in red wine produced from grape with skin. Resveratrol activates the anti-aging gene sirtuin; and AMP-activated protein kinase, which promotes mitochondrial functions if cellular energy is lowered; and autophagy, that is engaged in cleaning of the inside of a cell by degrading older or damaged cellular components. More importantly, resveratrol extends the lifespan of yeast and invertebrates and improves age-related signs in mice, especially those signs connected with insulin resistance and arteriosclerosis. Moderate alcohol consumption inhibits platelet aggregation, increases HDL cholesterol, and lowers blood sugar, meaning that ethanol protects cardiac infarction or diabetes. Further, resveratrol has more such beneficial effects. Since resveratrol is lipophilic, it is absorbed into the body more easily when taken with alcohol. Altogether, red wine, due to its synergistic effect caused by resveratrol and alcohol, could extend healthspan.Review Articledepartmental bulletin pape

    A Measurement of the Branching Fraction for the Inclusive B --> X(s) gamma Decays with the Belle Detector

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    We have measured the branching fraction of the inclusive radiative B meson decay B --> X(s) gamma to be Br(B->X(s)gamma)=(3.36 +/- 0.53(stat) +/- 0.42(sys) +0.50-0.54(th)) x 10^{-4}. The result is based on a sample of 6.07 x 10^6 BBbar events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.Comment: 14 pages, 6 Postsript figures, uses elsart.cl

    Measurements of Branching Fractions and Decay Amplitudes in B-> J/\psi K^* decays

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    The branching fractions and the decay amplitudes of B -> J/psi K^* decays are measured in a 29.4/fb data sample collected with the Belle detector at the KEKB electron-positron collider. The decay amplitudes of helicity states of the J/psi K^* system are determined from the full angular distribution of the final state particles in the transversity basis. The branching fractions are measured to be (1.29\pm0.05\pm0.13) \times 10^{-3} for neutral mesons and (1.28\pm0.07\pm0.14) \times 10^{-3} for charged mesons. The measured longitudinal and transverse (perpendicular to the transversity plane) amplitudes are |A_0|^2 = 0.62\pm0.02\pm0.03 and |A_{\perp}|^2 = 0.19\pm0.02\pm0.03, respectively. The value of |A_{\perp}|^2 shows that the CP even component dominates in the B^0 \to J/\psi K^{*0}(K_S\pi^0) decay.Comment: 17 pages, 3 figures, 5 tables, to appear in Phys. Lett.

    Search for Direct CP Violation in B -> K pi Decays

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    We search for direct CP violation in flavor specific B -> K pi decays by measuring the rate asymmetry between charge conjugate modes. The search is performed on a data sample of 11.1 million B B bar events recorded on the Upsilon(4S) resonance by the Belle experiment at KEKB. We measure 90% confidence intervals in the partial rate asymmetry A_CP of -0.25 < A_CP(K-/+ pi+/-) < 0.37, -0.40 < A_CP(K-/+ pi^0) < 0.36, and -0.53 < A_CP(K^0 pi-/+) < 0.82. By combining the K-/+ pi+/- and K-/+ pi^0 final states, we conclude that -0.22 < A_CP[K-/+(pi+/- + pi^0)] < 0.25 at the 90% confidence level.Comment: Submitted to PRD Rapid Communication

    Measurement of the CP Violation Parameter sin(2phi_1) in B^0_d Meson Decays

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    We present a measurement of the Standard Model CP violation parameter sin(2phi_1) based on a 10.5 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. One neutral B meson is reconstructed in the J/psi K_S, psi(2S) K_S, chi_{c1} K_S, eta_c K_S, J/psi K_L or J/psi pi^0 CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin(2phi_1) = 0.58 +0.32-0.34 (stat) +0.09-0.10 (syst).Comment: LaTex, 13 pages, 3 figures, submitted to P.R.
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