363 research outputs found

    First Detection of Near-Infrared Intraday Variations in the Seyfert 1 Nucleus NGC4395

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    We carried out a one-night optical V and near-infrared JHK monitoring observation of the least luminous Seyfert 1 galaxy, NGC4395, on 2004 May 1, and detected for the first time the intraday flux variations in the J and H bands, while such variation was not clearly seen for the K band. The detected J and H variations are synchronized with the flux variation in the V band, which indicates that the intraday-variable component of near-infrared continuum emission of the NGC4395 nucleus is an extension of power-law continuum emission to the near-infrared and originates in an outer region of the central accretion disk. On the other hand, from our regular program of long-term optical BVI and near-infrared JHK monitoring observation of NGC4395 from 2004 February 12 until 2005 January 22, we found large flux variations in all the bands on time scales of days to months. The optical BVI variations are almost synchronized with each other, but not completely with the near-infrared JHK variations. The color temperature of the near-infrared variable component is estimated to be T=1320-1710 K, in agreement with thermal emission from hot dust tori in active galactic nuclei (AGNs). We therefore conclude that the near-infrared variation consists of two components having different time scales, so that a small K-flux variation on a time scale of a few hours would possibly be veiled by large variation of thermal dust emission on a time scale of days.Comment: 4 pages including figures, accepted for publication in ApJ

    Adiponectin and AMP kinase activator stimulate proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells

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    <p>Abstract</p> <p>Background</p> <p>Adiponectin is a key mediator of the metabolic syndrome that is caused by visceral fat accumulation. Adiponectin and its receptors are known to be expressed in osteoblasts, but their actions with regard to bone metabolism are still unclear. In this study, we investigated the effects of adiponectin on the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells.</p> <p>Results</p> <p>Adiponectin receptor type 1 (AdipoR1) mRNA was detected in the cells by RT-PCR. The adenosine monophosphate-activated protein kinase (AMP kinase) was phosphorylated by both adiponectin and a pharmacological AMP kinase activator, 5-amino-imidazole-4-carboxamide-riboside (AICAR), in the cells. AdipoR1 small interfering RNA (siRNA) transfection potently knocked down the receptor mRNA, and the effect of this knockdown persisted for as long as 10 days after the transfection. The transfected cells showed decreased expressions of type I collagen and osteocalcin mRNA, as determined by real-time PCR, and reduced ALP activity and mineralization, as determined by von Kossa and Alizarin red stainings. In contrast, AMP kinase activation by AICAR (0.01–0.5 mM) in wild-type MC3T3-E1 cells augmented their proliferation, differentiation, and mineralization. BrdU assay showed that the addition of adiponectin (0.01–1.0 μg/ml) also promoted their proliferation. Osterix, but not Runx-2, appeared to be involved in these processes because AdipoR1 siRNA transfection and AICAR treatments suppressed and enhanced osterix mRNA expression, respectively.</p> <p>Conclusion</p> <p>Taken together, this study suggests that adiponectin stimulates the proliferation, differentiation, and mineralization of osteoblasts via the AdipoR1 and AMP kinase signaling pathways in autocrine and/or paracrine fashions.</p

    A novel variant fibrinogen, AαE11del, demonstrating the importance of AαE11 residue in thrombin binding

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    ArticleInternational journal of hematology. 114(5): 591-598. (2021)journal articl

    Suzaku Detection of an Intense X-Ray Flare from an A-type Star HD161084

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    We report a serendipitous detection of an intense X-ray flare from the Tycho reference source HD 161084 during a Suzaku observation of the Galactic Center region for 20 ks. The X-ray Imaging Spectrometer (XIS) recorded a flare from this A1-type dwarf or subgiant star with a flux of 1.4x10^{-12} erg s^{-1} cm^{-2} (0.5--10 keV) and a decay time scale of 0.5 hr. The spectrum is hard with a prominent Fe XXV K alpha emission line at 6.7 keV, which is explained by a 5 keV thin-thermal plasma model attenuated by a 1.4x10^{21} cm^{-2} extinction. The low extinction, which is consistent with the optical reddening, indicates that the source is a foreground star toward the Galactic Center region. Based on the spectroscopic parallax distance of 530 pc, the peak X-ray luminosity amounts to 1x10^{32} erg s^{-1} (0.5--10 keV). This is much larger than the X-ray luminosity of ordinary late-type main-sequence stars, and the X-ray emission is unattributable to a hidden late-type companion that comprises a wide binary system with the A-star. We discuss possible natures of HD 161084 and suggest that it is most likely an interacting binary with elevated magnetic activity in the companion such as the Algol-type system. The flux detected by Suzaku during the burst is 100 times larger than the quiescent level measured using the archived XMM-Newton and Chandra data. The large flux amplification makes this star a unique example among sources of this class.Comment: 8 pages, 6 figures, 2 tables, PASJ in pres

    Evidence of mature adipocyte proliferation regulated by proliferin

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    Despite much research, whether mature adipocytes proliferate remains controversial. Here, we examined 5-bromo-2&#x2032;-deoxyuridine (BrdU)-labelling of mature adipocytes. Although BrdU incorporation into subcutaneous adipocytes was less than that in visceral adipocytes, pioglitazone (Pio) treatment increased BrdU incorporation in subcutaneous, but not visceral, adipocytes in rats. Fully differentiated 3T3-L1 adipocytes exhibited an increase in cell number and BrdU incorporation with time, with this increase enhanced by Pio treatment. We therefore screened for genes that encode growth factors regulated by Pio, and selected proliferin (PLF). Both gene silencing of PLF by small interfering RNA and treatment with anti-PLF antibody suppressed proliferation in 3T3-L1 adipocytes. In adipocytes isolated from Pio-treated rats, the tissue-specific pattern of PLF expression was similar to that of BrdU incorporation. Administration of an anti-PLF antibody to mice reduced BrdU incorporation into adipocytes. Mature adipocytes thus have the ability to replicate, and this proliferation is positively regulated by PLF

    Overview of Legal Systems in the Asia-Pacific Region: Japan

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    This article provides a general description of the legal system of Japan. It further discusses aspects of legal education and legal practice in that country

    Sorafenib-induced apoptosis in colonic neuroendocrine carcinoma cells

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     Background: Neuroendocrine carcinoma (NEC) is a rare disease, and therapy for this malignant tumor is controversial. Conventionally, platinum doublet chemotherapy has been used for advanced gastroentero-pancreatic (GEP) neuroendocrine carcinoma (GEP- NEC), but the efficacy of molecular-targeted drugs for GEP-NEC is unknown. In this study, we investigated the antitumor effect of molecular-targeted drugs on colorectal neuroendocrine carcinoma cells. Materials and methods: A colonic neuroendocrine carcinoma cell line COLO320 was treated with molecular-targeted drugs, and cell growth suppression and apoptosis induction were evaluated. Results: The cytostatic effects of molecular-targeted drugs against COLO320 were higher in the order of sorafenib, sunitinib, rapamycin, and imatinib. Flow cytometry analysis showed that sorafenib induced G1 cell cycle arrest and a high rate of apoptosis. Sunitinib showed condensation and fragmentation of nuclear chromatin, but also necrosis with cell swelling. In contrast, sorafenib strongly induced apoptosis via condensation and fragmentation of nuclear chromatin. Sorafenib-induced apoptosis was due to caspase-3 activation, and this apoptosis was inhibited with a caspase inhibitor. Conclusion: Sorafenib induces apoptosis in COLO320 cells and is a potential therapeutic agent for colonic neuroendocrine carcinomas
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