3,834 research outputs found
A Study of Fermi-LAT GeV gamma-ray Emission towards the Magnetar-harboring Supernova Remnant Kesteven 73 and Its Molecular Environment
We report our independent GeV gamma-ray study of the young shell-type
supernova remnant (SNR) Kes 73 which harbors a central magnetar, and CO-line
millimeter observations toward the SNR. Using 7.6 years of Fermi-LAT
observation data, we detected an extended gamma-ray source ("source A") with
the centroid on the west of the SNR, with a significance of 21.6 sigma in
0.1-300 GeV and an error circle of 5.4 arcminute in angular radius. The
gamma-ray spectrum cannot be reproduced by a pure leptonic emission or a pure
emission from the magnetar, and thus a hadronic emission component is needed.
The CO-line observations reveal a molecular cloud (MC) at V_LSR~90 km/s, which
demonstrates morphological correspondence with the western boundary of the SNR
brightened in multiwavelength. The 12CO (J=2-1)/12CO (J=1-0) ratio in the left
(blue) wing 85-88 km/s is prominently elevated to ~1.1 along the northwestern
boundary, providing kinematic evidence of the SNR-MC interaction. This SNR-MC
association yields a kinematic distance 9 kpc to Kes 73. The MC is shown to be
capable of accounting for the hadronic gamma-ray emission component. The
gamma-ray spectrum can be interpreted with a pure hadronic emission or a
magnetar+hadronic hybrid emission. In the case of pure hadronic emission, the
spectral index of the protons is 2.4, very similar to that of the
radio-emitting electrons, essentially consistent with the diffusive shock
acceleration theory. In the case of magnetar+hadronic hybrid emission, a
magnetic field decay rate >= 10^36 erg/s is needed to power the magnetar's
curvature radiation.Comment: 7 figures, published in Ap
Synthesis and structure of the inclusion complex {NdQ[5]K@Q[10](H₂O)4}·4NO₃·20H₂O
Heating a mixture of Nd(NO₃)₃·6H₂O, KCl, Q[10] and Q[5] in HCl for 10 min affords the inclusion complex {NdQ[5]K@Q[10](H₂O)₄}·4NO₃·20H₂O. The structure of the inclusion complex has been investigated by single crystal X-ray diffraction and by X-ray Photoelectron spectroscopy (XPS)
2,2′-[(1E)-3-Phenylprop-2-ene-1,1-diyl]bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-one)
In the title molecule, C25H30O4, the two cyclohexene rings adopt envelope conformations. The two hydroxy groups are involved in the formation of intramolecular O—H⋯O hydrogen bonds. In the crystal structure, weak intermolecular C—H⋯O hydrogen bonds link molecules related by translation along the axis a into chains
Disruption of Smad4 impairs TGF-β/Smad3 and Smad7 transcriptional regulation during renal inflammation and fibrosis in vivo and in vitro
The mechanism by which TGF-β regulates renal inflammation and fibrosis is largely unclear; however, it is well accepted that its biological effects are mediated through Smad2 and Smad3 phosphorylation. Following activation, these Smads form heteromeric complex with Smad4 and translocate into the nucleus to bind and regulate the expression of target genes. Here we studied the roles of Smad4 to regulate TGF-β signaling in a mouse model of unilateral ureteral obstruction using conditional Smad4 knockout mice and in isolated Smad4 mutant macrophages and fibroblasts. Disruption of Smad4 significantly enhanced renal inflammation as evidenced by a greater CD45+ leukocyte and F4/80+ macrophage infiltration and upregulation of IL-1β, TNF-α, MCP-1, and ICAM-1 in the obstructed kidney and in IL-1β-stimulated macrophages. In contrast, deletion of Smad4 inhibited renal fibrosis and TGF-β1-induced collagen I expression by fibroblasts. Further studies showed that the loss of Smad4 repressed Smad7 transcription, leading to a loss of functional protein. This, in turn, inhibited IκBα expression but enhanced NF-κB activation, thereby promoting renal inflammation. Interestingly, deletion of Smad4 influenced Smad3-mediated promoter activities and the binding of Smad3 to the COL1A2 promoter, but not Smad3 phosphorylation and nuclear translocation, thereby inhibiting the fibrotic response. Thus, Smad4 may be a key regulator for the diverse roles of TGF-β1 in inflammation and fibrogenesis by interacting with Smad7 and Smad3 to influence their transcriptional activities in renal inflammation and fibrosis
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