18 research outputs found

    Hyper-luminous Dust Obscured Galaxies discovered by the Hyper Suprime-Cam on Subaru and WISE

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    We present the photometric properties of a sample of infrared (IR) bright dust obscured galaxies (DOGs). Combining wide and deep optical images obtained with the Hyper Suprime-Cam (HSC) on the Subaru Telescope and all-sky mid-IR (MIR) images taken with Wide-Field Infrared Survey Explorer (WISE), we discovered 48 DOGs with iKs>1.2i - K_\mathrm{s} > 1.2 and i[22]>7.0i - [22] > 7.0, where ii, KsK_\mathrm{s}, and [22] represent AB magnitude in the ii-band, KsK_\mathrm{s}-band, and 22 μ\mum, respectively, in the GAMA 14hr field (\sim 9 deg2^2). Among these objects, 31 (\sim 65 %) show power-law spectral energy distributions (SEDs) in the near-IR (NIR) and MIR regime, while the remainder show a NIR bump in their SEDs. Assuming that the redshift distribution for our DOGs sample is Gaussian, with mean and sigma zz = 1.99 ±\pm 0.45, we calculated their total IR luminosity using an empirical relation between 22 μ\mum luminosity and total IR luminosity. The average value of the total IR luminosity is (3.5 ±\pm 1.1) ×\times 101310^{13} L_{\odot}, which classifies them as hyper-luminous infrared galaxies (HyLIRGs). We also derived the total IR luminosity function (LF) and IR luminosity density (LD) for a flux-limited subsample of 18 DOGs with 22 μ\mum flux greater than 3.0 mJy and with ii-band magnitude brighter than 24 AB magnitude. The derived space density for this subsample is log ϕ\phi = -6.59 ±\pm 0.11 [Mpc3^{-3}]. The IR LF for DOGs including data obtained from the literature is well fitted by a double-power law. The derived lower limit for the IR LD for our sample is ρIR\rho_{\mathrm{IR}} \sim 3.8 ×\times 107^7 [L_{\odot} Mpc3^{-3}] and its contributions to the total IR LD, IR LD of all ultra-luminous infrared galaxies (ULIRGs), and that of all DOGs are >> 3 %, >> 9 %, and >> 15 %, respectively.Comment: 15 pages, 15 figures, and 3 tables, accepted for publication in PASJ (Subaru special issue

    The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)

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    We have carried out the first very long baseline interferometry (VLBI) imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA (KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in imaging compact maser features with a synthesized beam size of 2.7 milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a limited number of baselines within the length of shorter than approximately 650 km corresponding to 100 Mlambda in the uv-coverage. The central velocity and the velocity width of the 44 GHz methanol maser are consistent with those of the quiescent gas rather than the outflow traced by the SiO thermal line. The minimum component size among the maser features is ~ 5 mas x 2 mas, which corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc. The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0 x 10^{10} K, which are higher than estimated lower limit from a previous Very Large Array observation with the highest spatial resolution of ~ 50 mas. The 44 GHz class I methanol maser in IRAS 18151-1208 is found to be associated with the MM2 core, which is thought to be less evolved than another millimeter core MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure

    In situ nuclear DNA methylation in dilated cardiomyopathy: an endomyocardial biopsy study

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    Abstract Aims Although distinct DNA methylation patterns have been reported, its localization and roles remain to be defined in heart failure. We investigated the cellular and subcellular localization of DNA methylation and its pathophysiological significance in human failing hearts. Methods and results Using left ventricular (LV) endomyocardial biopsy specimens from 75 patients with dilated cardiomyopathy (DCM; age: 58 ± 14 years old, %female: 32%) and 20 patients without heart failure (controls; age: 56 ± 17 years old, %female: 45%), we performed immunohistochemistry and immunoelectron microscopy for methylated DNA, 5‐methylcytosine (5‐mC). We next investigated possible relations of the incidence of 5‐mC‐positive (%5‐mC+) cardiomyocytes with clinicopathological parameters. Immunopositivity for 5‐mC was detected in the cardiomyocytes and other cell types. The %5‐mC+ cardiomyocytes was significantly greater in DCM hearts than in controls (57 ± 13% in DCM vs. 25 ± 12% in controls, P < 0.0001). The localization of 5‐mC immunopositivity in cardiomyocyte nuclei coincided well with that of heterochromatin, as confirmed by immunoelectron microscopy. Substantial DNA methylation was also observed in interstitial non‐cardiomyocytes, but the incidences did not differ between control and DCM hearts (39 ± 7.9% in DCM vs. 41 ± 10% in controls, P = 0.4099). In DCM patients, the %5‐mC+ cardiomyocytes showed a significant inverse correlation with LV functional parameters such as heart rate (r = 0.2391, P = 0.0388), end‐diastolic pressure (r = 0.2397, P = 0.0397), and ejection fraction (r = −0.2917, P = 0.0111) and a positive correlation with LV dilatation (volume index at diastole; r = 0.2442, P = 0.0347; and volume index at systole; r = 0.3136, P = 0.0062) and LV hypertrophy (mass index; r = 0.2287, P = 0.0484)—that is, LV remodelling parameters. No significant correlations between DNA methylation and the histological parameters of the biopsies, including cardiomyocyte hypertrophy, fibrosis, and inflammatory cell infiltration, were noted. Conclusions The present study revealed increased nuclear DNA methylation in cardiomyocytes, but not other cell types, from DCM hearts, with predominant localization in the heterochromatin. Its significant relations with LV functional and remodelling parameters imply a pathophysiological significance of DNA methylation in heart failure

    Three-dimensional ultrastructure of capillary endothelial glycocalyx under normal and experimental endotoxemic conditions

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    Abstract Background Sugar-protein glycocalyx coats healthy endothelium, but its ultrastructure is not well described. Our aim was to determine the three-dimensional ultrastructure of capillary endothelial glycocalyx in the heart, kidney, and liver, where capillaries are, respectively, continuous, fenestrated, and sinusoidal. Methods Tissue samples were processed with lanthanum-containing alkaline fixative, which preserves the structure of glycocalyx. Results Scanning and transmission electron microscopy revealed that the endothelial glycocalyx layer in continuous and fenestrated capillaries was substantially thicker than in sinusoids. In the heart, the endothelial glycocalyx presented as moss- or broccoli-like and covered the entire luminal endothelial cell surface. In the kidney, the glycocalyx appeared to nearly occlude the endothelial pores of the fenestrated capillaries and was also present on the surface of the renal podocytes. In sinusoids of the liver, glycocalyx covered not only the luminal side but also the opposite side, facing the space of Disse. In a mouse lipopolysaccharide-induced experimental endotoxemia model, the capillary endothelial glycocalyx was severely disrupted; that is, it appeared to be peeling off the cells and clumping. Serum concentrations of syndecan-1, a marker of glycocalyx damage, were significantly increased 24 h after administration of lipopolysaccharide. Conclusions In the present study, we visualized the three-dimensional ultrastructure of endothelial glycocalyx in healthy continuous, fenestrated, and sinusoidal capillaries, and we also showed their disruption under experimental endotoxemic conditions. The latter may provide a morphological basis for the microvascular endothelial dysfunction associated with septic injury to organs
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