2,025 research outputs found

    Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud

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    N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC). We carried out new 12^{12}CO(JJ = 3-2) and 12^{12}CO(JJ = 1-0) observations using ASTE and ALMA. We have confirmed the existence of a giant molecular cloud (GMC) at VLSRV_\mathrm{LSR} \sim245 km s1^{-1} towards the southeast of the SNR using ASTE 12^{12}CO(JJ = 3-2) data at an angular resolution of \sim25"" (\sim6 pc in the LMC). Using the ALMA 12^{12}CO(JJ = 1-0) data, we have spatially resolved CO clouds along the southeastern edge of the SNR with an angular resolution of \sim1.8"" (\sim0.4 pc in the LMC). The molecular clouds show an expanding gas motion in the position-velocity diagram with an expansion velocity of 5\sim5 km s1^{-1}. The spatial extent of the expanding shell is roughly similar to that of the SNR. We also find tiny molecular clumps in the directions of optical nebula knots. We present a possible scenario that N103B exploded in the wind-bubble formed by the accretion winds from the progenitor system, and is now interacting with the dense gas wall. This is consistent with a single-degenerate scenario.Comment: 12 pages, 1 table, 8 figures, accepted for publication in The Astrophysical Journal (ApJ

    Neutral and Cationic Rare Earth Metal Alkyl and Benzyl Compounds with the 1,4,6-Trimethyl-6-pyrrolidin-1-yl-1,4-diazepane Ligand and Their Performance in the Catalytic Hydroamination/Cyclization of Aminoalkenes

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    A new neutral tridentate 1,4,6-trimethyl-6-pyrrolidin-1-yl-1,4-diazepane (L) was prepared. Reacting L with trialkyls M(CH2SiMe3)3(THF)2 (M = Sc, Y) and tribenzyls M(CH2Ph)3(THF)3 (M = Sc, La) yielded trialkyl complexes (L)M(CH2SiMe3)3 (M = Sc, 1; M = Y, 2) and tribenzyl complexes (L)M(CH2Ph)3 (M = Sc, 3; M = La, 4). Complexes 1 and 2 can be converted to their corresponding ionic compounds [(L)M(CH2SiMe3)2(THF)][B(C6H5)4] (M = Sc, Y) by reaction with [PhNMe2H][B(C6H5)4] in THF. Complexes 3 and 4 can be converted to cationic species [(L)M(CH2Ph)2]+ by reaction with [PhNMe2H][B(C6F5)4] in C6D5Br in the absence of THF. The neutral complexes 1-4 and their cationic derivatives were studied as catalysts for the hydroamination/cyclization of 2,2-diphenylpent-4-en-1-amine and N-methylpent-4-en-1-amine reference substrates and compared with ligand-free Sc, Y, and La neutral and cationic catalysts. The most effective catalysts in the series were the cationic L-yttrium catalyst (for 2,2-diphenylpent-4-en-1-amine) and the cationic lanthanum systems (for N-methylpent-4-en-1-amine). For the La catalysts, evidence was obtained for release of L from the metal during catalysis.

    Identifying chemokines as therapeutic targets in renal disease: Lessons from antagonist studies and knockout mice

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    Chemokines, in concert with cytokines and adhesion molecules, play multiple roles in local and systemic immune responses. In the kidney, the temporal and spatial expression of chemokines correlates with local renal damage and accumulation of chemokine receptor-bearing leukocytes. Chemokines play important roles in leukocyte trafficking and blocking chemokines can effectively reduce renal leukocyte recruitment and subsequent renal damage. However, recent data indicate that blocking chemokine or chemokine receptor activity in renal disease may also exacerbate renal inflammation under certain conditions. An increasing amount of data indicates additional roles of chemokines in the regulation of innate and adaptive immune responses, which may adversively affect the outcome of interventional studies. This review summarizes available in vivo studies on the blockade of chemokines and chemokine receptors in kidney diseases, with a special focus on the therapeutic potential of anti-chemokine strategies, including potential side effects, in renal disease. Copyright (C) 2004 S. Karger AG, Basel

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

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    We report the first observation of the charmless two-body mode B±ωK±B^{\pm} \to \omega K^{\pm} decay, and a new measurement of the branching fraction for the B±ωπ±B^{\pm} \to \omega \pi^{\pm} decay. The measured branching fractions are B(B±ωK±)=(9.22.3+2.6±1.0)×106{\cal B} (B^{\pm} \to \omega K^{\pm}) = (9.2{}^{+2.6}_{-2.3}\pm 1.0) \times 10^{-6} and B(B±ωπ±)=(4.21.8+2.0±0.5)×106{\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 %B(Bωπ)<8.1×106{\cal B} (B^- \to \omega \pi^-) < 8.1\times 10^{-6}. We also measure the partial rate asymmetry of B±ωK±B^{\pm}\to\omega K^{\pm} decays and obtain ACP=0.21±0.28±0.03{\cal A}_{CP} = -0.21 \pm 0.28 \pm 0.03. The results are based on a data sample of 29.4 fb1^{-1} collected on the Υ(4S)\Upsilon(4S) resonance by the Belle detector at the KEKB e+ee^{+} e^{-} collider.Comment: 5 pages, 4 figures, resubmitted to Phys. Rev. Let

    Mesurement of the B0 - anti-B0 Mixing Parameter Delta m_d using Semileptonic B0 Decays

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    We present a measurement of the B^0-B^0bar mixing parameter Delta m_d using neutral B meson pairs in a 29.1 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We exclusively reconstruct one neutral B meson in the semileptonic B^0 \to D^{*-}\ell^+\nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Delta m_d = (0.494 +- 0.012 +- 0.015) ps^{-1}, where the first error is statistical and the second error is systematic.Comment: 10 pages, 3 figures, Published in Phys.Rev.Lett. 89, 251803 (2002
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