Selective inhibition of 5-lipoxygenase by natural compounds isolated from Chinese plants, Artemisia rubripes Nakai

AbstractThree of four natural compounds, which are caffeic acid, eupatilin and 4′-demethyleupatilin, isolated from Chinese plant, Artemisia rubripes Nakai selectively inhibited 5-lipoxygenase of cultured mastocytoma cells. Half-inhibition doses (ID50) for caffeic acid, eupatilin and 4′-demethyleupatilin were 3.7, 14 and 18 × 10−6 M, respectively. The inhibition by caffeic acid was non-competitive types. Prostaglandin synthase activities were little inhibited by eupatilin and 4′-demethyleupatilin, but rather stimulated by affeic acid. The formation of leukotriene C4 and D4 by mast tumor cells was almost completely suppressed by these compounds at 10−4 M

An inclusive measurement of the photon energy spectrum in b->s gamma decays

We report a fully inclusive measurement of the flavour changing neutral current decay b->s gamma in the energy range 1.8 GeV < E* < 2.8 GeV, covering 95% of the total spectrum. Using 140 fb^-1 we obtain BF(b->s gamma)= 3.55 +/- 0.32 +0.30-0.31 +0.11-0.07, where the errors are statistical, systematic and from theory corrections. We also measure the first and second moments of the photon energy spectrum above 1.8 GeV and obtain = 2.292 +/- 0.026 +/- 0.034 GeV and -^2 = 0.0305 +/- 0.0074 +/- 0.0063 GeV^2, where the errors are statistical and systematic.Comment: RevTex4, 6 pages, Submitted to Phys.Rev.Lett. Replaced: added table of systematic errors. New results take into account radiative J/Psi decay

Observation of the decay B^0->D+D*-

We report the first observation of the decay B^0->D+-D*-+ with the Belle detector at the KEKB e^+e^- collider operated at the Upsilon(4S) resonance. The sum of branching fractions B(B^0->D+D*-)+B(B^0->D-D*+) is measured to be (1.17+-0.26+0.22-0.25)x10^-3 using the full reconstruction method where both charmed mesons from B^0 decays are reconstructed. A consistent value ((1.48+-0.38+0.28-0.31)x10^-3) is obtained using a partial reconstruction technique that only uses the slow pion from the D*- ->bar D^0pi- decay and a fully reconstructed D+ to reconstruct the B^0.Comment: 10 pages, 3 figure

Observation of Large CP Violation and Evidence for Direct CP Violation in B0-->pi+pi- Decays

We report the first observation of CP-violating asymmetries in B0 --> pi+pi- decays based on a 140 fb-1 data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson as a B0 --> pi+pi- CP eigenstate and identify the flavor of the accompanying B meson from its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes Apipi = +0.58+/-0.15(stat)+/-0.07(syst) and Spipi = -1.00+/-0.21(stat)+/-0.07(syst). We rule out the CP-conserving case, Apipi=Spipi=0, at a level of 5.2 standard deviations. We also find evidence for direct CP violation with a significance at or greater than 3.2 standard deviations for any Spipi value.Comment: 9 pages, 3 figure

Measurement of the Branching Fraction for B->eta' K and Search for B->eta'pi+

We report measurements for two-body charmless B decays with an eta' meson in the final state. Using 11.1X10^6 BBbar pairs collected with the Belle detector, we find BF(B^+ ->eta'K^+)=(79^+12_-11 +-9)x10^-6 and BF(B^0 -> eta'K^0)=(55^+19_-16 +-8)x10^-6, where the first and second errors are statistical and systematic, respectively. No signal is observed in the mode B^+ -> eta' pi^+, and we set a 90% confidence level upper limit of BF(B^+-> eta'pi^+) eta'K^+- decays is investigated and a limit at 90% confidence level of -0.20<Acp<0.32 is obtained.Comment: Submitted to Physics Letters

Observation of B+- -> omega K+- Decay

We report the first observation of the charmless two-body mode $B^{\pm} \to \omega K^{\pm}$ decay, and a new measurement of the branching fraction for the $B^{\pm} \to \omega \pi^{\pm}$ decay. The measured branching fractions are ${\cal B} (B^{\pm} \to \omega K^{\pm}) = (9.2{}^{+2.6}_{-2.3}\pm 1.0) \times 10^{-6}$ and ${\cal B} (B^{\pm} \to \omega \pi^{\pm}) = (4.2{}^{+2.0}_{-1.8}\pm 0.5) \times 10^{-6}$. %and we set 90% confidence level upper limits of %${\cal B} (B^- \to \omega \pi^-) < 8.1\times 10^{-6}$. We also measure the partial rate asymmetry of $B^{\pm}\to\omega K^{\pm}$ decays and obtain ${\cal A}_{CP} = -0.21 \pm 0.28 \pm 0.03$. The results are based on a data sample of 29.4 fb$^{-1}$ collected on the $\Upsilon(4S)$ resonance by the Belle detector at the KEKB $e^{+} e^{-}$ collider.Comment: 5 pages, 4 figures, resubmitted to Phys. Rev. Let

Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays

We present measurements of the Cabibbo-suppressed decays Lambda_c^+ --> Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+ --> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+ --> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy). Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+ K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams, are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+ and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-. This analysis was performed using 32.6 fb^{-1} of data collected by the Belle detector at the asymmetric e+ e- collider KEKB.Comment: Submitted to Phys. Lett. B. v2: A small correction to the Authorlist was made. An earlier version of this analysis was released as BELLE-CONF-0130, hep-ex/010800

Measurement of the B --> K^* gamma Branching Fractions and Asymmetries

We report measurements of the radiative decay B --> K^*\gamma. The analysis is based on a data sample containing 85.0*10^6 B meson pairs collected by the Belle detector at the KEKB storage ring. We measure branching fractions of Br(B^0 --> K^{*0}\gamma) = (4.01 \pm 0.21 \pm 0.17)*10^{-5} and Br(B^+ --> K^{*+}\gamma) = (4.25 \pm 0.31 \pm 0.24)*10^{-5}, where the first and second errors are statistical and systematic, respectively. The isospin asymmetry between B^0 and B^+ decay widths is measured to be \Delta_{0+} = +0.012 \pm 0.044 \pm 0.026. We search for a partial rate asymmetry between CP conjugate modes, and find A_{cp}(B --> K^*\gamma) = =0.015 \pm 0.044 \pm 0.012.Comment: 10 pages, 5 figures, submitted to Phys. Rev.