241 research outputs found
Effect of vitamin B12 derivatives on urinary excretion of methylmalonic acid in liver diseases
1. Twenty.one patients with liver diseases were studied for their urinary mehylmalonic acid excretion after a valine load by means of an improved thin layer chromatography. 2. Methylmalonic acid positive cases were found in four out of the ten patients with cirrhosis of the liver, all four with cirrhosis and diabetes mellitus, and none with acute hepatitis of icteric phase. No apparent
correlation was found between the methylmalonic acid excretion and the extent of hepatic damage. 3. A large amount of methylmalonic acid found in the case (S. I.)
with cirrhosis of the liver and diabetes mellitus after the valine load was not corrected by cyanocobalamin but by DBCC, suggesting an impaired transformation from cyanocobalamin to DBCC. However, the nature of the impairment remains unknown.</p
Shedding Light on the Compton-thick Active Galactic Nucleus in the Ultra-luminous Infrared Galaxy UGC 5101 with Broadband X-ray Spectroscopy
We report the broadband X-ray spectra of the ultra-luminous infrared galaxy
(ULIRG) UGC 5101 in the 0.25-100 keV band observed with Swift/Burst Alert
Telescope (BAT), NuSTAR, Suzaku, XMM-Newton, and Chandra. A Compton-thick AGN
obscured with a hydrogen column density of cm
is detected above 10 keV. A spectral fit with a numerical torus model favors a
large half opening angle of the torus, degrees, suggesting that the
covering fraction of material heavily obscuring the X-ray source is moderate.
The intrinsic 2-10 keV luminosity is determined to be erg s, which is 2.5 times larger than the previous
estimate using only data below 10 keV with a simple spectral model. We find
that UGC 5101 shows the ratio between the [O IV] 26 m line and 2-10 keV
luminosities similar to those of normal Seyfert galaxies, along with other
ULIRGs observed with NuSTAR, indicating that a significant portion of local
ULIRGs are not really "X-ray faint" with respect to the flux of forbidden lines
originating from the narrow line region (NLR). We propose a possible scenario
that (1) the AGN in UGC 5101 is surrounded not only by Compton-thick matter
located close to the equatorial plane but also by Compton-thin ( cm) matter in the torus-hole region and (2) it is
accreting at a high Eddington rate with a steep UV to X-ray spectral energy
distribution. Nevertheless, we argue that AGNs in many ULIRGs do not look
extraordinary (i.e., extremely X-ray faint), as suggested by recent works,
compared with normal Seyferts.Comment: 11 pages, 7 figures, accepted for publication in Ap
Characteristics of Stiffness and Strength of V-Joint in Tubular Offshore Structures(Mechanics, Strength & Structural Design)
Quantum mechanically driven structural-spin glass in two dimensions at finite temperature
In magnetic materials, spins sometimes freeze into spatially disordered
glassy states. Glass forming liquids or structural glasses are found very often
in three dimensions. However, in two dimensions(2D) it is believed that both
spin glass and structural glass can never exist at a finite temperature because
they are destroyed by thermal fluctuations. Using a large-scale quantum Monte
Carlo simulation, we discover a quantum-mechanically driven 2D glass phase at
finite temperatures. Our platform is an Ising spin model with a quantum
transverse field on a frustrated triangular lattice. How the present glass
phase is formed is understood by the following three steps. First, by the
interplay of geometrical frustration and quantum fluctuation, part of the spins
spontaneously form an antiferromagnetic honeycomb spin-superstructure. Then,
small randomness in the bond interaction works as a relevant perturbation to
this superstructure and breaks it up into {\it domains}, making it a structural
glass. The glassiness of the superstructure, in turn, generates an emergent
random magnetic field acting on the remaining fluctuating spins and freezes
them. The shape of domains thus formed depends sensitively on the quenching
process, which is one of the characteristic features of glass, originating from
a multi-valley free-energy landscape. The present system consists only of {\it
a single} bistable Ising degree of freedom, which naturally does not become a
structural glass alone nor a spin glass alone. Nevertheless, a glass having
both types of nature emerges in the form of coexisting two-component glasses,
algebraic structural-glass and long-range ordered spin-glass. This new concept
of glass-forming mechanism opens a way to realize functional glasses even in
low dimensional systems.Comment: 21pages, 14figure
AKARI IRC 2.5-5 um Spectroscopy of Infrared Galaxies over a Wide Luminosity Range
We present the result of a systematic infrared 2.5-5 um spectroscopic study
of 22 nearby infrared galaxies over a wide infrared luminosity range (10 <
log(L_IR / Lsun) < 13) obtained from AKARI Infrared Camera (IRC). The unique
band of the AKARI IRC spectroscopy enables us to access both the 3.3 um
polycyclic aromatic hydrocarbon (PAH) emission feature from star forming
activity and the continuum of torus-dust emission heated by an active galactic
nucleus (AGN). Applying our AGN diagnostics to the AKARI spectra, we discover
14 buried AGNs. The large fraction of buried AGNs suggests that AGN activity
behind the dust is almost ubiquitous in ultra-/luminous infrared galaxies
(U/LIRGs). We also find that both the fraction and energy contribution of
buried AGNs increase with infrared luminosity from 10 < log(L_IR / Lsun) < 13,
including normal infrared galaxies with log (L_IR / Lsun) < 11. The energy
contribution from AGNs in the total infrared luminosity is only ~7% in LIRGs
and ~20% in ULIRGs, suggesting that the majority of the infrared luminosity
originates from starburst activity. Using the PAH emission, we investigate the
luminosity relation between star formation and AGN. We find that these infrared
galaxies exhibit higher star formation rates than optically selected Seyfert
galaxies with the same AGN luminosities, implying that infrared galaxies could
be an early evolutionary phase of AGN.Comment: 13 pages, 8 figures, accepted for publication in Ap
SHED-CM for ALS Treatment
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, characterized by the loss of upper and lower motor neurons, for which an effective treatment has yet to be developed. Previous reports have shown that excessive oxidative stress, related to mitochondrial dysfunction and the accumulation of misfolding protein, contributes to ALS pathology. In terms of treatment, it remains necessary to identify effective medicines for multiple therapeutic targets and have additive effects against several disorders. In this study, we investigated stem cells from human exfoliated deciduous teeth (SHED), which release many factors, such as neurotrophic factors and cytokines, and are applied to treat neurological diseases. Specifically, we examined whether SHED-conditioned medium (CM), i.e., the serum-free culture supernatant of SHED, reduced mutant SOD1-induced intracellular aggregates and neurotoxicity. We found that SHED-CM significantly suppressed the mutant SOD1-induced intracellular aggregates and neurotoxicity. The neuroprotective effects of SHED-CM are partly related to heat shock protein and the activation of insulin-like growth factor-1 receptor. SHED-CM also had a protective effect on induced pluripotent stem cell-derived motor neurons. Moreover, SHED-CM was effective against not only familial ALS but also sporadic ALS. Overall, these results suggest that SHED-CM could be a promising treatment for slowing the progression of ALS
Nodal Structure of Superconductors with Time-Reversal Invariance and Z2 Topological Number
A topological argument is presented for nodal structures of superconducting
states with time-reversal invariance. A generic Hamiltonian which describes a
quasiparticle in superconducting states with time-reversal invariance is
derived, and it is shown that only line nodes are topologically stable in
single-band descriptions of superconductivity. Using the time-reversal
symmetry, we introduce a real structure and define topological numbers of line
nodes. Stability of line nodes is ensured by conservation of the topological
numbers. Line nodes in high-Tc materials, the polar state in p-wave paring and
mixed singlet-triplet superconducting states are examined in detail.Comment: 11 pages, 8 figure
A NuSTAR and XMM-Newton Study of the Two Most Actively Star-forming Green Pea Galaxies (SDSS J0749+3337 and SDSS J0822+2241)
We explore X-ray evidence for the presence of active galactic nuclei (AGNs)
in the two most actively star-forming Green Pea galaxies (GPs), SDSS J0749+3337
and SDSS J0822+2241, which have star-formation rates (SFRs) of
yr and yr, respectively. The GPs have red
mid-infrared (MIR) spectral energy distributions and higher 22 m
luminosities than expected from a proxy of the SFR (H luminosity),
consistent with hosting AGNs with 2-10 keV luminosities of erg
s. We thus obtain and analyze the first hard ( 10 keV) X-ray data
observed with NuSTAR and archival XMM-Newton data below 10 keV. From the NuSTAR
20 ksec data, however, we find no significant hard X-ray emission. By
contrast, soft X-ray emission with 0.5--8 keV luminosities of
erg s is significantly detected in both targets, which can be explained
only by star formation (SF). A possible reason for the lack of clear evidence
is that a putative AGN torus absorbs most of the X-ray emission. Applying a
smooth-density AGN torus model, we determine minimum hydrogen column densities
along the equatorial plane () consistent with the
non-detection. The results indicate
cm for SDSS J0749+3337 and
cm for SDSS J0822+2241. Therefore, the GPs may host such heavily
obscured AGNs. Otherwise, no AGN exists and the MIR emission is ascribed to SF.
Active SF in low-mass galaxies is indeed suggested to reproduce red MIR colors.
This would imply that diagnostics based on MIR photometry data alone may
misidentify such galaxies as AGNs.Comment: 12 pages, 3 tables, 5 figures, accepted for publication in Ap
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