91 research outputs found
Black Hole Formation and Explosion from Rapidly Rotating Very Massive Stars
We explore the formation process of a black hole (BH) through the
pair-instability collapse of a rotating Population III very massive star in
axisymmetric numerical relativity. As the initial condition, we employ a
progenitor star which is obtained by evolving a rapidly rotating zero-age main
sequence (ZAMS) star with mass until it reaches a pair instability
region. We find that for such rapidly rotating model, a fraction of the mass,
, forms a torus surrounding the remnant BH of mass and an outflow is driven by a hydrodynamical effect. We also
perform simulations, artificially reducing the initial angular velocity of the
progenitor star, and find that only a small or no torus is formed and no
outflow is driven. We discuss the possible evolution scenario of the remnant
torus for the rapidly rotating model by considering the viscous and
recombination effects and show that if the energy of erg is
injected from the torus to the envelope, the luminosity and timescale of the
explosion could be of the orders of erg/s and yrs, respectively. We
also point out the possibility for observing gravitational waves associated
with the BH formation for the rapidly rotating model by ground-based
gravitational-wave detectors.Comment: 19 pages, 16 figures, submitted to Ap
Acoustic and thermal anomalies in a liquid–glass transition of racemic S(+)–R(−) ketoprofen
Acoustic and thermal properties of pharmaceutical racemic S(+)–R(−) ketoprofen were investigated in wide temperature range including glassy, supercooled liquid and liquid states by Brillouin scattering and temperature modulated DSC. Sound velocity and acoustic attenuation exhibited clear changes at 265 K indicating a liquid–glass transition and showed the typical structural relaxation above Tg. The high value of the fragility index m = 71 was determined by the dispersion of the complex heat capacity. New relaxation map was suggested in combination with previous study of dielectric measurement
Evaluation of the immunoregulatory capacities of feed microbial materials in porcine intestinal immune and epithelial cells.
The establishment of drug-free feeding systems has been required for secure and healthy lives- tock production. Although functional feed materials containing microorganisms as alternatives to enhance intestinal immunity are expected to be beneficial for reducing diarrhoea caused by pathogens in weaned piglets, the effects of such materials on porcine intestinal cells have not been investigated in detail. Therefore, this work evaluated the immunoregulatory functions of microbial feed materials in porcine intestinal immune and epithelial cells. Porcine immune cells isolated from Peyer?s patches and mesenteric lymph nodes were stimulated with six different feed materials containing microorganisms, and evaluated for lymphocyte mitogenicity and cytokine inductions. In addition, porcine intestinal epithelial cells were stimulated with the materials before treatment with heat-killed enterotoxigenic Escherichia coli (ETEC), and analyzed for the proinflammatory cytokine expressions. The material containing Bifidobacterium thermophilum significantly augmented lymphocytes? mitogenicity and also induced a high expression of IL-2, IL-6 and IFN-γ in immune cells, and inhibited ETEC-induced overexpression of IL-6 and IL-8 via regulation of Toll-like receptor signaling. These results suggest that this feed material stimulates intestinal epithelial and immune cells to exert immunoregulation, suggesting that this feed is expected to contribute to promoting the health of piglets without using antimicrobial feed materials.Fil: Kumagae, Naosuke. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón. Scientific Feed Laboratory Co. Ltd.; JapónFil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; JapónFil: Tomosada, Yohsuke. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; JapónFil: Kobayashi, Hisakazu . Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; JapónFil: Kanmani, Paulraj. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón. Japan Society for the Promotion of Science; JapónFil: Aso, Hisashi . Tohoku University. Graduate School of Agricultural Science. Cell Biology Laboratory; JapónFil: Sasaki, Takashi . Scientific Feed Laboratory Co. Ltd.; JapónFil: Yoshida, Motohiko . Scientific Feed Laboratory Co. Ltd.; JapónFil: Tanabe, Hiroshi. Scientific Feed Laboratory Co. Ltd.; JapónFil: Shibata, Isao. Scientific Feed Laboratory Co. Ltd.; JapónFil: Saito, Tadao . Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; JapónFil: Kitazawa, Haruki. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japó
Alternative mRNA Splicing in Three Venom Families Underlying a Possible Production of Divergent Venom Proteins of the Habu Snake, Protobothrops flavoviridis
Snake venoms are complex mixtures of toxic proteins encoded by various gene families that function synergistically to incapacitate prey. A huge repertoire of snake venom genes and proteins have been reported, and alternative splicing is suggested to be involved in the production of divergent gene transcripts. However, a genome-wide survey of the transcript repertoire and the extent of alternative splicing still remains to be determined. In this study, the comprehensive analysis of transcriptomes in the venom gland was achieved by using PacBio sequencing. Extensive alternative splicing was observed in three venom protein gene families, metalloproteinase (MP), serine protease (SP), and vascular endothelial growth factors (VEGF). Eleven MP and SP genes and a VEGF gene are expressed as a total of 81, 61, and 8 transcript variants, respectively. In the MP gene family, individual genes are transcribed into different classes of MPs by alternative splicing. We also observed trans-splicing among the clustered SP genes. No other venom genes as well as non-venom counterpart genes exhibited alternative splicing. Our results thus indicate a potential contribution of mRNA alternative and trans-splicing in the production of highly variable transcripts of venom genes in the habu snake
Direct evidence for pitavastatin induced chromatin structure change in the KLF4 gene in endothelial cells.
Statins exert atheroprotective effects through the induction of specific transcriptional factors in multiple organs. In endothelial cells, statin-dependent atheroprotective gene up-regulation is mediated by Kruppel-like factor (KLF) family transcription factors. To dissect the mechanism of gene regulation, we sought to determine molecular targets by performing microarray analyses of human umbilical vein endothelial cells (HUVECs) treated with pitavastatin, and KLF4 was determined to be the most highly induced gene. In addition, it was revealed that the atheroprotective genes induced with pitavastatin, such as nitric oxide synthase 3 (NOS3) and thrombomodulin (THBD), were suppressed by KLF4 knockdown. Myocyte enhancer factor-2 (MEF2) family activation is reported to be involved in pitavastatin-dependent KLF4 induction. We focused on MEF2C among the MEF2 family members and identified a novel functional MEF2C binding site 148 kb upstream of the KLF4 gene by chromatin immunoprecipitation along with deep sequencing (ChIP-seq) followed by luciferase assay. By applying whole genome and quantitative chromatin conformation analysis {chromatin interaction analysis with paired end tag sequencing (ChIA-PET), and real time chromosome conformation capture (3C) assay}, we observed that the MEF2C-bound enhancer and transcription start site (TSS) of KLF4 came into closer spatial proximity by pitavastatin treatment. 3D-Fluorescence in situ hybridization (FISH) imaging supported the conformational change in individual cells. Taken together, dynamic chromatin conformation change was shown to mediate pitavastatin-responsive gene induction in endothelial cells
Changes in blood glucose and insulin responses to intravenous glucose tolerance tests and blood biochemical values in adult female Japanese black bears (Ursus thibetanus japonicus)
The metabolic mechanisms to circannual changes in body mass of bears have yet to be elucidated. We hypothesized that the Japanese black bear (Ursus thibetanus japonicus) has a metabolic mechanism that efficiently converts carbohydrates into body fat by altering insulin sensitivity during the hyperphagic stage before hibernation. To test this hypothesis, we investigated the changes in blood biochemical values and glucose and insulin responses to intravenous glucose tolerance tests (IVGTT) during the active season (August, early and late November). Four, adult, female bears (5-17 years old) were anesthetized with 6 mg/kg TZ (tiletamine HCl and zolazepam HCl) in combination with 0.1 mg/kg acepromazine maleate. The bears were injected intravenously with glucose (0.5 g/kg of body mass), and blood samples were obtained before, at, and intermittently after glucose injection. The basal triglycerides concentration decreased significantly with increase in body mass from August to November. Basal levels of plasma glucose and serum insulin concentrations were not significantly different among groups. The results of IVGTT demonstrated the increased peripheral insulin sensitivity and glucose tolerance in early November. In contrast, peripheral insulin resistance was indicated by the exaggerated insulin response in late November. Our findings suggest that bears shift their glucose and lipid metabolism from the stage of normal activity to the hyperphagic stage in which they show lipogenicpredominant metabolism and accelerate glucose uptake by increasing the peripheral insulin sensitivity
Rhodium-Catalyzed Synthesis, Crystal Structures, and Photophysical Properties of [6]Cycloparaphenylene Tetracarboxylates.
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