7,684 research outputs found
Laboratory infrared studies relevant to Io: A satellite to the planet Jupiter
To explain the unidentified spectral features of Io, as obtained by the Voyager infrared spectrometer experiment, the infrared absorption spectra of a number of stable sulfur and oxygen compounds was measured and compared to the Voyager data. Based on the reference absorption bands of Na2SO4 and possibly SO2, the infrared data on Io in the region 700 to 200 per cm appear to represent an emission spectrum. Given the strong evidence for an oxidized crustal environment and the presence of sodium in the Io torus, the absorption spectra of the tested materials support the probability of Na2SO4 occurrence on Io
Properties of charmed and bottom hadrons in nuclear medium: Results for and hypernuclei
This reports our recent studies on changes in properties of heavy hadrons
containing at least a charm or a bottom quark in nuclear matter, and that the
results for the and hypernuclei are studied
quantitatively. Comparisons are made with the results for the
hypernuclei studied previously in the same approach. It is shown that although
the scalar and vector potentials for the , and
in the hypernuclei multiplet with the same baryon numbers are quite
similar, the wave functions obtained, e.g., for state, are very
different. The probability density distribution in
Pb is much more pushed away from the center than that for
the in Pb due to the Coulomb force. On the contrary,
the probability density distributions in hypernuclei
are much larger near the origin than those for the in the
hypernuclei due to its heavy mass. A possibility of nuclear bound
(atomic) states is also briefly discussed.Comment: 12 pages, 7 embedded figures, uses PTP-Tex environment (all
included), Invited talk presented at YITP-RCNP Workshop on "Chiral
Restoration in Nuclear Medium", October 7-9, 2002, YITP Kyoto University,
Japan, to be published in the proceeding
Crystalline sulfur dioxide: Crystal field splittings, absolute band intensities and complex refractive indices derived from infrared spectra
The infrared absorption spectra of thin crystalline films of sulfur dioxide at 90 K are reported in the 2700 to 450/cm region. The observed multiplicity of the spectral features in the regions of fundamentals is attributed to factor group splittings of the modes in a biaxial crystal lattice and the naturally present minor S-34, S-36, and O-18 isotopic species. Complex refractive indices determined by an iterative Kramers-Kronig analysis of the extinction data, and absolute band strengths derived from them, are also reported in this region
Colonic carcinoma with multiple small bowel perforations mimicking intestinal obstruction
BACKGROUND: Carcinoma of the colon may present with perforation proximal to the site of malignancy. Caecum is the commonest site of perforation if the ileocecal valve is patent and the jejunal and ileal perforations are very rare. CASE PRESENTATION: A 35 year male presented with intestinal obstruction. Emergency laparotomy revealed carcinoma of the transverse colon with multiple pinpoint perforations along antimesenteric border of ileum, which were wrapped with omentum, and no peritoneal contamination was present. Extended right hemicolectomy with jejunocolic anastomosis was done. Patient made uneventful recovery in postoperative period and was treated with adjuvant chemotherapy. CONCLUSION: Patients with colonic carcinoma and incompetent ileocecal valve may present with intestinal perforation. Increased intraluminal pressure and closed loop obstruction may lead to ischemia and perforation of the small bowel
Absorption and resonance Raman spectra of Pb2, Pb3 and Pb4 in xenon matrices
Lead metal was vaporized and trapped in solid xenon at 12K. Electronic absorption and resonance Raman spectra were recorded of the resulting matrix, which was shown to contain Pb2, Pb3, and possibly Pb4 molecular species. The vibrational frequency for Pb2 is determined to be 108/cm for the ground state, with a dissociation energy of 82000/cm. Ad3h symmetry is indicated for the Pb3 species, with nu sub 1=117/cm and nu sub 2 = 96 /cm. The existence of Pb4 is suggested by a fundamental and overtone of 111/cm spacing
Analysis of direct CP violation in decays
We investigate the possibility of observing the direct CP violation in the
decay modes and within the Standard Model.
Including the contributions arising from the tree, annihilation, QCD as well as
electroweak penguins with both time- and space-like components, we find that
the direct CP asymmetry in is very small % but
in decay it can be as large as 4%. Approximately
charged mesons are required to experimentally observe the CP asymmetry
parameter for the later case. Since this is easily accessible with the
currently running B factories, the decay mode may be pursued
to look for CP violation.Comment: Latex, 14 page
Enhanced susceptibility of cyclin kinase inhibitor p21 knockout mice to high fat diet induced atherosclerosis
Cyclin kinase inhibitor p21 is one of the most potent inhibitors of aortic smooth muscle cell proliferation, a key mediator of atherosclerosis. This study tests if p2l deficiency will result in severe atherosclerosis in a mouse model. p21-/- and strain matched wild type mice were fed with high fat diet for 21 weeks. Analysis for biochemical parameters (cholesterol, triglycerides) in serum and mRNA expression of CD36, HO-1, TGF-β, IFN-γ, TNF-α, PPAR-γ and NADPH oxidase components (p22phox, NOX-1 and Rac-1) was performed in aortic tissues by Real Time PCR. p21-/- mice gained significantly (p < 0.01) more weight than wild type mice, triglycerides (p < 0.05) and cholesterol levels (p < 0.01) were more pronounced in the sera of p21-/- compared to wild type mice fed with high fat diet. High fat diet resulted in significantly decreased TGF-β (p < 0.02), HO-l (p < 0.02) and increased CD36 (p < 0.03) mRNA expression in aortic tissues of p21-/- mice compared to animal fed with regular diet. IFN-γ mRNA expression (235 ± 11 folds) increased significantly in high fat diet fed p21-/- mice and a multifold modulation of PPAR-γ(136 ± 7), p22phox, NOX-1 and Rac-1 (15–35-folds) mRNA in aortic tissues from p21-/- mice compared to the wild type mice. Severity of atherosclerotic lesions was significantly higher in p21-/- compared to wild type mice. The results demonstrate that the deficiency of p21 leads to altered expression of pro-atherogenic genes, and severe atherosclerosis in mice fed with high fat diet. This opens the possibility of p21 protein as a therapeutic tool to control progression of atherosclerosis
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