257 research outputs found
Prediction of the Stable Structures of Saccharides by Means of Molecular Orbital Calculation ‒ an Approach in the “Case Study” Class etc.
departmental bulletin pape
A massive quiescent galaxy in a group environment at
We report on the spectroscopic confirmation of a massive quiescent galaxy at
in the COSMOS field with Keck/MOSFIRE. The object was
first identified as a galaxy with suppressed star formation at
from the COSMOS2020 catalog. The follow-up
spectroscopy with MOSFIRE in the -band reveals a faint [OII] emission and
the Balmer break, indicative of evolved stellar populations. We perform the
spectral energy distribution fitting using both the photometry and spectrum to
infer physical properties. The obtained stellar mass is high () and the current star formation rate is more than 1 dex
below that of main-sequence galaxies at . Its star formation history
suggests that this galaxy experienced starburst at followed by a rapid
quenching phase. This is one of the youngest quiescent galaxies at and is
likely a galaxy in the process of being quenched. An unique aspect of the
galaxy is that it is in an extremely dense region; there are four massive
star-forming galaxies at located within 150 physical
kpc from the galaxy. Interestingly, three of them have strongly overlapping
virial radii with that of the central quiescent galaxy (), suggesting that the over-density region is likely the
highest redshift candidate of a dense group with a spectroscopically confirmed
quiescent galaxy at the center. The group provides us with an unique
opportunity to gain insights into the role of the group environment for
quenching at 4 - 5 corresponding to the formation epoch of massive
elliptical galaxies in the local Universe.Comment: 13 pages, 7 figures, 2 tables; submitted to Ap
Vacuum structure of spontaneously broken N=2 supersymmetric gauge theory
We analyze the vacuum structure of spontaneously broken N=2 supersymmetric
gauge theory with the Fayet-Iliopoulos term. Our theory is based on the gauge
group SU(2) \times U(1) with N_f=1,2 massless quark hypermultiplets having the
same U(1) charges. In the classical potential, there are degenerate vacua even
in the absence of supersymmetry. It is shown that this vacuum degeneracy is
smoothed out, once quantum corrections are taken into account. In N_f=1 case,
the effective potential is found to be so-called runaway type, and there is
neither well-defined vacuum nor local minimum. On the other hand, in N_f=2
case, while there is also the runaway direction in the effective potential, we
find the possibility that there appears the local minimum with broken
supersymmetry at the degenerate dyon point.Comment: 27 pages, revtex, 14 figures, some typographical errors are
corrected. To be published in Phys. Rev.
Chemical Characterization of a Volatile Dubnium Compound, DbOCl3
The formation and the chemical characterization of single atoms of dubnium (Db, element 105), in the form of its volatile oxychloride, was investigated using the on-line gas phase chromatography technique, in the temperature range 350–600 °C. Under the exactly same chemical conditions, comparative studies with the lighter homologues of Group 5 in the Periodic Table clearly indicate the volatility sequence being NbOCl3 > TaOCl3 ≥ DbOCl3. From the obtained experimental results, thermochemical data for DbOCl3 were derived. The present study delivers reliable experimental information for theoretical calculations on chemical properties of transactinides
Selection of antigenically advanced variants of seasonal influenza viruses
Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent se
Selection of antigenically advanced variants of seasonal influenza viruses.
Influenza viruses mutate frequently, necessitating constant updates of vaccine viruses. To establish experimental approaches that may complement the current vaccine strain selection process, we selected antigenic variants from human H1N1 and H3N2 influenza virus libraries possessing random mutations in the globular head of the haemagglutinin protein (which includes the antigenic sites) by incubating them with human and/or ferret convalescent sera to human H1N1 and H3N2 viruses. We also selected antigenic escape variants from human viruses treated with convalescent sera and from mice that had been previously immunized against human influenza viruses. Our pilot studies with past influenza viruses identified escape mutants that were antigenically similar to variants that emerged in nature, establishing the feasibility of our approach. Our studies with contemporary human influenza viruses identified escape mutants before they caused an epidemic in 2014-2015. This approach may aid in the prediction of potential antigenic escape variants and the selection of future vaccine candidates before they become widespread in nature.This work was supported by the Bill & Melinda Gates Foundation Global Health Grant OPPGH5383; National Institute of Allergy and Infectious Diseases (NIAID) Public Health Service research grants (USA); ERATO (Japan Science and Technology Agency); the Center for Research on Influenza Pathogenesis (CRIP) funded by the NIAID Contracts HHSN266200700010C and HHSN27 2201400008C; the Japan Initiative for Global Research Network on Infectious Diseases; Grants-in-Aid for Specially Promoted Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan; Grants-in-Aid from the Ministry of Health, Labour and Welfare, Japan; grants from the Strategic Basic Research Program of the Japan Science and Technology Agency; and by the Advanced Research & Development Programs for Medical Innovation from the Japan Agency for Medical Research and Development (AMED). C.A.R. was supported by a University Research Fellowship from the Royal Society. The authors acknowledge a Netherlands Organisation for Scientific Research (NWO) VICI grant, European Union (EU) FP7 programs EMPERIE (223498) and ANTIGONE (278976); Human Frontier Science Program (HFSP) program grant P0050/2008; Wellcome 087982AIA; and NIH Director's Pioneer Award DP1-OD000490-01. D.F.B and D.J.S. acknowledge CamGrid, the University of Cambridge distributed computer system. The Melbourne WHO Collaborating Centre for Reference and Research on Influenza is supported by the Australian Government Department of Health.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nmicrobiol.2016.5
Size - Stellar Mass Relation and Morphology of Quiescent Galaxies at in Public Fields
We present the results of a systematic study of the rest-frame optical
morphology of quiescent galaxies at using the Near-Infrared Camera
(NIRCam) onboard . Based on a sample selected by color or
color, we focus on 26 quiescent galaxies with
at with publicly
available data. Their sizes are constrained by fitting the S\'ersic
profile to all available NIRCam images. We see a negative correlation between
the observed wavelength and the size in our sample and derive their size at the
rest-frame taking into account this trend. Our quiescent
galaxies show a significant correlation between the rest-frame size and the stellar mass at . The analytical fit for them at
implies that our size - stellar mass relations
are below those at lower redshifts, with the amplitude of
at . This value agrees with the
extrapolation from the size evolution of quiescent galaxies at in the
literature, implying that the size of quiescent galaxies increases
monotonically from . Our sample is mainly composed of galaxies with
bulge-like structures according to their median S\'ersic index and axis ratio
of and , respectively. On the other hand, there is a
trend of increasing fraction of galaxies with low S\'ersic index, suggesting
might be the epoch of onset of morphological transformation with a
fraction of very notable disky quenched galaxies.Comment: 23 pages, 16 figures, 2 tables; submitted to Ap
Semi-quantitative analyses of metabolic systems of human colon cancer metastatic xenografts in livers of superimmunodeficient NOG mice
Analyses of energy metabolism in human cancer have been difficult because of rapid turnover of the metabolites and difficulties in reducing time for collecting clinical samples under surgical procedures. Utilization of xenograft transplantation of human-derived colon cancer HCT116 cells in spleens of superimmunodeficient NOD/SCID/IL-2Rγnull (NOG) mice led us to establish an experimental model of hepatic micrometastasis of the solid tumor, whereby analyses of the tissue sections collected by snap-frozen procedures through newly developed microscopic imaging mass spectrometry (MIMS) revealed distinct spatial distribution of a variety of metabolites. To perform intergroup comparison of the signal intensities of metabolites among different tissue sections collected from mice in fed states, we combined matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI–TOF-IMS) and capillary electrophoresis–mass spectrometry (CE–MS), to determine the apparent contents of individual metabolites in serial tissue sections. The results indicated significant elevation of ATP and energy charge in both metastases and the parenchyma of the tumor-bearing livers. To note were significant increases in UDP-N-acetyl hexosamines, and reduced and oxidized forms of glutathione in the metastatic foci versus the liver parenchyma. These findings thus provided a potentially important method for characterizing the properties of metabolic systems of human-derived cancer and the host tissues in vivo
Biological and Structural Characterization of a Host-Adapting Amino Acid in Influenza Virus
Two amino acids (lysine at position 627 or asparagine at position 701) in the polymerase subunit PB2 protein are considered critical for the adaptation of avian influenza A viruses to mammals. However, the recently emerged pandemic H1N1 viruses lack these amino acids. Here, we report that a basic amino acid at position 591 of PB2 can compensate for the lack of lysine at position 627 and confers efficient viral replication to pandemic H1N1 viruses in mammals. Moreover, a basic amino acid at position 591 of PB2 substantially increased the lethality of an avian H5N1 virus in mice. We also present the X-ray crystallographic structure of the C-terminus of a pandemic H1N1 virus PB2 protein. Arginine at position 591 fills the cleft found in H5N1 PB2 proteins in this area, resulting in differences in surface shape and charge for H1N1 PB2 proteins. These differences may affect the protein's interaction with viral and/or cellular factors, and hence its ability to support virus replication in mammals
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