5,679 research outputs found
Protection from experimental colitis by theaflavin-3,3'-digallate correlates with inhibition of IKK and NF-κB activation
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
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
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
CO(1-0) line data unveils the presence of a giant molecular filament
(GMF G45.3+0.1; length 75 pc, mass 1.110 M)
having a coherent velocity structure at [53, 63] km s. 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 pc 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 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 G11.110.12: a site of multiple hub-filament systems and colliding filamentary clouds
To probe star formation processes, we present a multi-scale and
multi-wavelength investigation of the `Snake' nebula/infrared dark cloud
G11.110.12 (hereafter, G11; length 27 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 ) and protostars are identified. The
CO(2-1), CO(2-1), and NH(1,1) line data reveal a noticeable
velocity oscillation toward G11, as well as its left part (or part-A) around
V of 31.5 km s, and its right part (or part-B) around V
of 29.5 km s. 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 0.55 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 3500-10000 AU) surrounding a dusty
envelope-like feature (extent 18000 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 HCO line data show two cloud
components with a velocity separation of 2 km s 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
It is shown that if the charginos decay into very soft leptons or hadrons +
due to degeneracy/ near- degeneracy with the LSP or the sneutrino,
the observability of the recently proposed signal via the single photon (+ soft
particles) + 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 ?
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 m show a central region (having M 225 M) surrounded by five parsec-scale filaments,
revealing a hub-filament system (HFS). In the {\it Herschel} column density
() map, filaments are identified with higher aspect ratios
(length/diameter) and lower values (0.1--2.4
10 cm), while the central hub is found with a lower
aspect ratio and higher values (3.5--7.0
10 cm). 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
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 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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