1,983 research outputs found
Observation of Very High Energy Gamma Rays from HESS J1804-216 with CANGAROO-III Telescopes
We observed the unidentified TeV gamma-ray source HESS J1804-216 with the
CANGAROO-III atmospheric Cerenkov telescopes from May to July in 2006. We
detected very high energy gamma rays above 600 GeV at the 10 sigma level in an
effective exposure of 76 hr. We obtained a differential flux of
(5.0+/-1.5_{stat}+/-1.6_{sys})\times 10^{-12}(E/1 TeV)^{-\alpha}
cm^{-2}s^{-1}TeV^{-1} with a photon index \alpha of 2.69 +/- 0.30_{stat} +/-
0.34_{sys}, which is consistent with that of the H.E.S.S. observation in 2004.
We also confirm the extended morphology of the source. By combining our result
with multi-wavelength observations, we discuss the possible counterparts of
HESS J1804-216 and the radiation mechanism based on leptonic and hadronic
processes for a supernova remnant and a pulsar wind nebula.Comment: 11 pages, 12 figures, Accepted in Ap
Dense Molecular Gas Associated with the Circumnuclear Star Forming Ring in the Barred Spiral Galaxy NGC 6951
We present high resolution (3" - 5") observations of CO(1-0) and HCN(1-0)
emission from the circumnuclear star forming ring in the barred spiral galaxy
NGC 6951, a host of a type-2 Seyfert, using the Nobeyama Millimeter Array and
45 m telescope. We find that most of the HCN emission is associated with the
circumnuclear ring, where vigorous star formation occurs. The HCN to CO
integrated intensity ratio is also enhanced in the star forming ring; the peak
value of HCN/CO ratio is 0.18, which is comparable to the ratio in the
starbursts NGC 253 and M82. The formation mechanism of dense molecular gas has
been investigated. We find that the shocks along the orbit crowding do not
promote the formation of the dense molecular gas effectively but enhance the
presence of low density GMCs. Instead, gravitational instabilities of the gas
can account for the dense molecular gas formation. The HCN/CO ratio toward the
Seyfert nucleus of NGC 6951 is a rather normal value (0.086), in contrast with
other Seyferts NGC 1068 and M51 where extremely high HCN/CO value of ~ 0.5 have
been reported.Comment: 33 pages, 17 figures, to appear in the Astrophysical Journa
A child presenting with tuberculous spondylitis in a single third cervical vertebra: a case report
An initial event in insect innate immune response: structural and biological studies of interactions between β-1,3-glucan and the N-terminal domain of β-1,3-glucan recognition protein
In response to invading microorganisms, insect β-1,3-glucan recognition protein (βGRP), a soluble receptor in the hemolymph, binds to the surfaces of bacteria and fungi and activates serine protease cascades that promote destruction of pathogens by means of melanization or expression of antimicrobial peptides. Here we report on the NMR solution structure of the N-terminal domain of βGRP (N-βGRP) from Indian meal moth (Plodia interpunctella), which is sufficient to activate the prophenoloxidase (proPO) pathway resulting in melanin formation. NMR and isothermal calorimetric titrations of N-βGRP with laminarihexaose, a glucose hexamer containing β-1,3 links, suggest a weak binding of the ligand. However, addition of laminarin, a glucose polysaccharide (~ 6 kDa) containing β-1,3 and β-1,6 links that activates the proPO pathway, to N-βGRP results in the loss of NMR cross-peaks from the backbone 15N-1H groups of the protein, suggesting the formation of a large complex. Analytical ultra centrifugation (AUC) studies of formation of N-βGRP:laminarin complex show that ligand-binding induces sel-fassociation of the protein:carbohydrate complex into a macro structure, likely containing six protein and three laminarin molecules (~ 102 kDa). The macro complex is quite stable, as it does not undergo dissociation upon dilution to sub-micromolar concentrations. The structural model thus derived from the present studies for N-βGRP:laminarin complex in solution differs from the one in which a single N-βGRP molecule has been proposed to bind to a triple helical form of laminarin on the basis of an X-ray crystallographic structure of N-βGRP:laminarihexaose complex [Kanagawa, M., Satoh, T., Ikeda, A., Adachi, Y., Ohno, N., and Yamaguchi, Y. (2011) J. Biol. Chem. 286, 29158-29165]. AUC studies and phenoloxidase activation measurements carried out with the designed mutants of N-βGRP indicate that electrostatic interactions involving Asp45, Arg54, and Asp68 between the ligand-bound protein molecules contribute in part to the stability of N-βGRP:laminarin macro complex and that a decreased stability is accompanied by a reduced activation of the proPO pathway. Increased β-1,6 branching in laminarin also results in destabilization of the macro complex. These novel findings suggest that ligand-induced self-association of βGRP:β-1,3-glucan complex may form a platform on a microbial surface for recruitment of downstream proteases, as a means of amplification of the initial signal of pathogen recognition for the activation of the proPO pathway
Role of P-selectin in platelet sequestration in pulmonary capillaries during endotoxemia
Background: There is growing evidence that platelets accumulate in the lung and contribute to the pathogenesis of acute lung injury during endotoxemia. The aims of the present study were to localize platelet sequestration in the pulmonary microcirculation and to investigate the role of P-selectin as a molecular mechanism of platelet endothelial cell interaction. Methods: We used in vivo fluorescence microscopy to quantify the kinetics of fluorescently labeled erythrocytes and platelets in alveolar capillary networks in rabbit lungs. Results: Six hours after onset of endotoxin infusion we observed a massive rolling along and firm adherence of platelets to lung capillary endothelial cells whereas under control conditions no platelet sequestration was detected. P-selectin was expressed on the surface of separated platelets which were incubated with endotoxin and in lung tissue. Pretreatment of platelets with fucoidin, a P-selectin antagonist, significantly attenuated the endotoxin-induced platelet rolling and adherence. In contrast, intravenous infusion of fucoidin in endotoxin-treated rabbits did not inhibit platelet sequestration in pulmonary capillaries. Conclusion: We conclude that platelets accumulate in alveolar capillaries following endotoxemia. P-selectin expressed on the surface of platelets seems to play an important role in mediating this platelet-endothelial cell interaction. Copyright (c) 2006 S. Karger AG, Basel
3-D Inlet Shock-Boundary Layer Interactions - PIV Database for the Second SBLI Workshop
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97090/1/AIAA2012-3214.pd
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 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
Observation of Radiative Decay
We report the observation of the decay with a
statistical significance of in 78.1 \ifb of data collected by the
Belle experiment at the KEKB collider. This is the first observation
of a flavor-changing radiative decay of a charmed meson. The Cabibbo- and
color-suppressed decays , are also observed for
the first time. We measure branching fractions \br(D^{0} \to \phi \gamma)
= [ 2.60^{+0.70}_{-0.61} \stat {}^{+0.15}_{-0.17} \syst ] \times 10^{-5},
\br(D^{0} \to \phi \pi^{0})
= [ 8.01 \pm 0.26 \stat \pm 0.47 \syst ] \times 10^{-4}, and \br(D^{0} \to
\phi \eta) = [ 1.48 \pm 0.47 \stat \pm 0.09 \syst ] \times 10^{-4}.Comment: 9 pages, 4 figures, Belle Preprint 2003-24, KEK Preprint 2003-75,
updated version of BELLE-CONF-0346 (contributed paper to the XXI
International Symposium on Lepton and Photon Interactions at High
Energies,Fermilab Aug 11-16,2003). to appear in Phys. Rev. Let
Search for the Lepton-Flavor-Violating Decay at Belle
We have searched for the Lepton Flavor Violating decay using a data sample of 84.3 fb accumulated with the Belle detector
at KEK. The -meson was detected through the decay modes: and . No signal candidates are found, and we
obtain an upper limit for the branching fraction at the 90% confidence level.Comment: Submitted to Phys.Rev.Let
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