5,679 research outputs found

    Protection from experimental colitis by theaflavin-3,3'-digallate correlates with inhibition of IKK and NF-κB activation

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    Background and purpose: Inflammatory bowel disease (IBD) is associated with activation of nuclear factor κ B (NF-κB) involved in regulating the expression of inducible nitric oxide synthase (iNOS) and proinflammatory cytokine genes. As theaflavin-3,3'-digallate (TFDG), the most potent anti-oxidant polyphenol of black tea, down-regulates NF-κB activation, we investigated if TFDG is beneficial in colonic inflammation by suppressing iNOS and proinflammatory cytokines. Experimental approach: The in vivo efficacy of TFDG was assessed in mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis. Both mRNA and protein levels of proinflammatory cytokines and iNOS were analyzed in colon tissue treated with or without TFDG. NF-κB activation was determined by electrophoretic mobility shift assay and levels of NF-κB inhibitory protein (IκBα) were analyzed by Western blotting. Key results: Oral administration of TFDG (5 mg kg-1 daily i.g.) significantly improved TNBS-induced colitis associated with decreased mRNA and protein levels of TNF-α, IL-12, IFN- and iNOS in colonic mucosa. DNA binding and Western blotting revealed increase in NF-κB activation and IκB depletion in TNBS-treated mice from Day 2 through Day 8 with a maximum at Day 4, which resulted from increased phosphorylation of IκB and higher activity of IκB kinase (IKK). Pretreatment with TFDG markedly inhibited TNBS-induced increases in nuclear localization of NF-κBα, cytosolic IKK activity and preserved IκBα in colon tissue. Conclusions and Implications: TFDG exerts protective effects in experimental colitis and inhibits production of inflammatory mediators through a mechanism that, at least in part, involves inhibition of NF-κB activation

    Development of 0.2C-CrMnMoV Ultra High Strength Steel

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    A study was carried out to develop a low alloy ultra high strength steel by induction melting and thermomechanical treatment (TMT) containing alloying elements like carbon, manganese, molybdenum, chromium and vanadium. A base alloy was prepared with 0.24%C, 1.16% Mn, 0.23% Si, 5.61% Cr, 0.42%V, 1.01% Mo, 0.026%S and 0.032%P. It showed tensile strength of 1467 MPa, yield strength of about 1180 MPa, impact strength of 6.3J and elongation of 5.9% in as-tempered condition. Other alloy was prepared by addition of 0.054% titanium with the base composition. It displayed tensile strength, yield strength, impact toughness and % elongation of 1615 MPa, 1240 MPa, 8.2J and 6.15%, respectively. The optical, SEM and TEM microstructures confirmed that the base alloy and the titanium alloy consisted with tempered lath martensites. The remaining part of the ingot was further processed by the thermomechanical treatment. The ingots were rolled in two passes, initially at 950 C and subsequently at 850 C followed by immediate cooling in oil. The TMT plates of the base alloy confirmed the tensile strength of 1755 MPa, yield strength in excess of 1460 MPa and impact strength of 9.1J. The titanium added TMT plate displayed tensile strength of 1860 MPa, yield strength of 1580 MPa and impact strength of 10.1J. Microstructures of titanium added alloy consisted finer lath martensite and precipitates of titanium carbides/carbonitrides. It was observed that the addition of titanium significantly improved the mechanical properties of 0.2C-Cr Mn Mo V alloys and the mechanical properties were also improved significantly by thermomechanical treatment

    Simultaneous evidence of edge collapse and hub-filament configurations: A rare case study of a Giant Molecular Filament G45.3+0.1

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    We study multiwavelength and multiscale data to investigate the kinematics of molecular gas associated with the star-forming complexes G045.49+00.04 (G45E) and G045.14+00.14 (G45W) in the Aquila constellation. An analysis of the FUGIN 13^{13}CO(1-0) line data unveils the presence of a giant molecular filament (GMF G45.3+0.1; length ∼\sim75 pc, mass ∼\sim1.1×\times106^{6} M⊙_{\odot}) having a coherent velocity structure at [53, 63] km s−1^{-1}. The GMF G45.3+0.1 hosts G45E and G45W complexes at its opposite ends. We find large scale velocity oscillations along GMF G45.3+0.1, which also reveals the linear velocity gradients of −-0.064 and ++0.032 km s−1^{-1} pc−1^{-1} at its edges. The photometric analysis of point-like sources shows the clustering of young stellar object (YSO) candidate sources at the filament's edges where the presence of dense gas and HII regions are also spatially observed. The Herschel continuum maps along with the CHIMPS 13^{13}CO(3-2) line data unravel the presence of parsec scale hub-filament systems (HFSs) in both the sites, G45E and G45W. Our study suggests that the global collapse of GMF G45.3+0.1 is end-dominated, with addition to the signature of global nonisotropic collapse (GNIC) at the edges. Overall, GMF G45.3+0.1 is the first observational sample of filament where the edge collapse and the hub-filament configurations are simultaneously investigated. These observations open up the new possibility of massive star formation, including the formation of HFSs.Comment: 23 pages, 12 figures, 1 table, Accepted for publication in The Astrophysical Journa

    Galactic `Snake' IRDC G11.11−-0.12: a site of multiple hub-filament systems and colliding filamentary clouds

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    To probe star formation processes, we present a multi-scale and multi-wavelength investigation of the `Snake' nebula/infrared dark cloud G11.11−-0.12 (hereafter, G11; length ∼\sim27 pc). Spitzer images hint at the presence of sub-filaments (in absorption), and reveal four infrared-dark hub-filament system (HFS) candidates (extent << 6 pc) toward G11, where massive clumps (>> 500 M⊙M_{\odot}) and protostars are identified. The 13^{13}CO(2-1), C18^{18}O(2-1), and NH3_{3}(1,1) line data reveal a noticeable velocity oscillation toward G11, as well as its left part (or part-A) around Vlsr_{lsr} of 31.5 km s−1^{-1}, and its right part (or part-B) around Vlsr_{lsr} of 29.5 km s−1^{-1}. The common zone of these cloud components is investigated toward the center's G11 housing one HFS. Each cloud component hosts two sub-filaments. In comparison to part-A, more ATLASGAL clumps are observed toward part-B. The JWST near-infrared images discover one infrared-dark HFS candidate (extent ∼\sim0.55 pc) around the massive protostar G11P1 (i.e., G11P1-HFS). Hence, the infrared observations reveal multiple infrared-dark HFS candidates at multi-scale in G11. The ALMA 1.16 mm continuum map shows multiple finger-like features (extent ∼\sim3500-10000 AU) surrounding a dusty envelope-like feature (extent ∼\sim18000 AU) toward the central hub of G11P1-HFS. Signatures of forming massive stars are found toward the center of the envelope-like feature. The ALMA H13^{13}CO+^{+} line data show two cloud components with a velocity separation of ∼\sim2 km s−1^{-1} toward G11P1. Overall, the collision process, the ``fray and fragment'' mechanism, and the ``global non-isotropic collapse'' scenario seem to be operational in G11.Comment: 20 pages, 13 figures, 3 Tables, Accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS) Journa

    On the Observability of "Invisible" / "Nearly Invisible" Charginos

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    It is shown that if the charginos decay into very soft leptons or hadrons + E̸\not{E} due to degeneracy/ near- degeneracy with the LSP or the sneutrino, the observability of the recently proposed signal via the single photon (+ soft particles) + E̸\not{E} channel crucially depends on the magnitude of the \SNU mass due to destructive interferences in the matrix element squared. If the \SNU's and, consequently, left-sleptons are relatively light, the size of the signal, previously computed in the limit \MSNU \to \infty only, is drastically reduced. We present the formula for the signal cross section in a model independent way and discuss the observability of the signal at LEP 192 and NLC energies.Comment: 27 pages, Late

    Star-forming site RAFGL 5085: Is a perfect candidate of hub-filament system ?

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    To investigate the star formation process, we present a multi-wavelength study of a massive star-forming site RAFGL 5085, which has been associated with the molecular outflow, HII region, and near-infrared cluster. The continuum images at 12, 250, 350, and 500 μ\mum show a central region (having Mclump_{\rm clump} ∼\sim225 M⊙_{\odot}) surrounded by five parsec-scale filaments, revealing a hub-filament system (HFS). In the {\it Herschel} column density (N(H2)N({{\rm{H}}}_{2})) map, filaments are identified with higher aspect ratios (length/diameter) and lower N(H2)N({{\rm{H}}}_{2}) values (∼\sim0.1--2.4 ×\times1021^{21} cm−2^{-2}), while the central hub is found with a lower aspect ratio and higher N(H2)N({{\rm{H}}}_{2}) values (∼\sim3.5--7.0 ×\times1021^{21} cm−2^{-2}). The central hub displays a temperature range of [19, 22.5]~K in the {\it Herschel} temperature map, and is observed with signatures of star formation (including radio continuum emission). The JCMT 13^{13}CO(J= 3--2) line data confirm the presence of the HFS and its hub is traced with supersonic and non-thermal motions having higher Mach number and lower thermal to non-thermal pressure ratio. In the 13^{13}CO position-velocity diagrams, velocity gradients along the filaments toward the HFS appear to be observed, suggesting the gas flow in the RAFGL 5085 HFS and the applicability of the clump-fed scenario.Comment: 15 pages, 8 figures; Accepted for publication in Journal of Astrophysics and Astronomy (JOAA
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