MOIRCS Deep Survey. VII: NIR Morphologies of Star-forming Galaxies at Redshift z~1

We investigate rest-frame near-infrared (NIR) morphologies of a sample of 139 galaxies with M_{s} >= 1 x 10^{10} M_{sun} at z=0.8-1.2 in the GOODS-North field using our deep NIR imaging data (MOIRCS Deep Survey, MODS). We focus on Luminous Infrared Galaxies (LIRGs), which dominate high star formation rate (SFR) density at z~1, in the sample identified by cross-correlating with the Spitzer/MIPS 24um source catalog. We perform two-dimensional light profile fitting of the z~1 galaxies in the Ks-band (rest-frame J-band) with a single component Sersic model. We find that at z~1, ~90% of LIRGs have low Sersic indices (n<2.5, similar to disk-like galaxies) in the Ks-band, and those disk-like LIRGs consist of ~60% of the whole disk-like sample above M_{s} >= 3 x 10^{10} M_{sun}. The z~1 disk-like LIRGs are comparable or ~20% small at a maximum in size compared to local disk-like galaxies in the same stellar mass range. If we examine rest-frame UV-optical morphologies using the HST/ACS images, the rest-frame B-band sizes of the z~1 disk-like galaxies are comparable to those of the local disk-like galaxies as reported by previous studies on size evolution of disk-like galaxies in the rest-frame optical band. Measuring color gradients (galaxy sizes as a function of wavelength) of the z~1 and local disk-like galaxies, we find that the z~1 disk-like galaxies have 3-5 times steeper color gradient than the local ones. Our results indicate that (i) more than a half of relatively massive disk-like galaxies at z~1 are in violent star formation epochs observed as LIRGs, and also (ii) most of those LIRGs are constructing their fundamental disk structure vigorously. The high SFR density in the universe at z~1 may be dominated by such star formation in disk region in massive galaxies.Comment: 16 pages, 15 figures, accepted for publication in PASJ. Catalog data will be available at http://astr.tohoku.ac.jp/MODS/wiki/index.php soo

Accelerating revised RBF neural network

This study aimed to accelerate the segmentation of organs in medical imaging with the revised radial basis function (RBF) network, using a graphics processing unit (GPU). We segmented the lung and liver regions from 250 chest x-ray computed tomography (CT) images and 160 abdominal CT images, respectively, using the revised RBF network. We compared the time taken to segment images and their accuracy between serial processing by a single-core central processing unit (CPU), parallel processing using four CPU cores, and GPU processing. Segmentation times for lung and liver organ regions shortened to 57.80 and 35.35 seconds for CPU parallel processing and 20.16 and 11.02 seconds for GPU processing, compared to 211.03 and 124.21 seconds for CPU serial processing, respectively. The concordance rate of the segmented region to the normal region in slices excluding the upper and lower ends (173 lung and 111 liver slices) was 98% for lung and 96% for liver. The use of CPU parallel processing and GPU shortened the organ segmentation time in the revised RBF network without compromising segmentation accuracy. In particular, segmentation time was shortened to less than 10% with GPU. This processing method will contribute to workload reduction in imaging analysis

浸潤および血管新生を通しての人肝細胞癌の進行におけるケラチン19分子の役割

BACKGROUND: Keratin (K) 19-positive hepatocellular carcinoma (HCC) is well known to have a higher malignant potential than K19-negative HCC: However, the molecular mechanisms involved in K19-mediated progression of HCC remain unclear. We attempted to clarify whether K19 directly affects cell survival and invasiveness in association with cellular senescence or epithelial-mesenchymal transition (EMT) in K19-positive HCC. METHODS: K19 expression was analysed in 136 HCC surgical specimens. The relationship of K19 with clinicopathological factors and survival was analysed. Further, the effect of K19 on cell proliferation, invasion, and angiogenesis was examined by silencing K19 in the human HCC cell lines, HepG2, HuH-7, and PLC/PRF/5. Finally, we investigated HCC invasion, proliferation, and angiogenesis using K19-positive HCC specimens. RESULTS: Analysis of HCC surgical specimens revealed that K19-positive HCC exhibited higher invasiveness, metastatic potential, and poorer prognosis. In vitro experiments using the human HCC cell lines revealed that K19 silencing suppressed cell growth by inducting apoptosis or upregulating p16 and p27, resulting in cellular senescence. In addition, transfection with K19 siRNA upregulated E-cadherin gene expression, significantly inhibited the invasive capacity of the cells, downregulated angiogenesis-related molecules such as vasohibin-1 (VASH1) and fibroblast growth factor 1 (FGFR1), and upregulated vasohibin-2 (VASH2). K19-positive HCC specimens exhibited a high MIB-1 labelling index, decreased E-cadherin expression, and high microvessel density around cancer foci. CONCLUSION: K19 directly promotes cancer cell survival, invasion, and angiogenesis, resulting in HCC progression and poor clinical outcome. K19 may therefore be a novel drug target for the treatment of K19-positive HCC.博士（医学）・乙第1399号・平成29年3月15日© The Author(s). 2016 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

MOIRCS Deep Survey V: A Universal Relation for Stellar Mass and Surface Brightness of Galaxies

We present a universal linear correlation between the stellar mass and surface brightness (SB) of galaxies at 0.3<z<3, using a deep K-band selected catalog in the GOODS-North region. The correlation has a nearly constant slope, independent of redshift and color of galaxies in the rest-z frame. Considering unresolved compact galaxies, the tight correlation gives a lower boundary of SB for a given stellar mass; lower SB galaxies are prohibited over the boundary. The universal slope suggests that the stellar mass in galaxies was build up over their cosmic histories in a similar manner irrelevant to galaxy mass, as oppose to the scenario that massive galaxies mainly accumulated their stellar mass by major merging. In contrast, SB shows a strong dependence on redshift for a given stellar mass. It evolves as (1+z)^(-2.0~-0.8), in addition to dimming as (1+z)^4 by the cosmological expansion effect. The brightening depends on galaxy color and stellar mass. The blue population (rest-frame U-V<0), which is dominated by young and star-forming galaxies, evolves as ~(1+z)^(-0.8 +-0.3) in the rest-V band. On the other hand, the red population (U-V>0) and the massive galaxies (M_*>10^(10)M_sun) shows stronger brightening, (1+z)^(-1.5+-0.1). Based on the comparison with galaxy evolution models, we find that the phenomena are well explained by the pure luminosity evolution of galaxies out to z~3.Comment: 10 pages, 9 figures. Accepted for publication in Ap