575 research outputs found
Phase equilibria for H2 + CO2 + H2O system containing gas hydrates
Isothermal phase equilibrium (pressure-composition in the gas phase) for the ternary system of H2 + CO2 + H2O has been investigated in the presence of gas hydrate phase. Three-phase equilibrium pressure increases with the H2 composition of gas phase. The Raman spectra suggest that H2 is not enclathrated in the hydrate-cages and behaves only like the diluent gas toward the formation of CO2 hydrate. This fact is also supported by the thermodynamic analysis using Soave-Redlich-Kwong equation of state. © 2005 Elsevier B.V. All rights reserved
A novel nonsense mutation in a Japanese family with ataxia with oculomotor apraxia type 2 (AOA2)
We report a 67-year-old Japanese woman with ataxia with oculomotor apraxia type 2 (AOA2). She was born to consanguineous parents and showed a teenage onset, a slowly progressive cerebellar ataxia and sensory-motor neuropathy and an elevated level of serum alpha-fetoprotein (AFP). All of these clinical features were consistent with typical AOA2. She lacked oculomotor apraxia, as frequently observed in previously reported AOA2 patients. She was homozygous for a novel nonsense mutation, Glu385Ter (E385X), in the senataxin gene (SETX). To our knowledge, this is the fifth Japanese family with genetically confirmed AOA2. The mutations in SETX in Japanese AOA2 families are heterogeneous, except for M274I, which has been found in two unrelated families. More extensive screening by serum AFP followed by molecular genetic analysis of SETX in patients with Friedreich's ataxia-like phenotype may show that AOA2 is more common in Japan than previously thought. Journal of Human Genetics (2009) 54, 746-748; doi: 10.1038/jhg.2009.104; published online 6 November 2009ArticleJOURNAL OF HUMAN GENETICS. 54(12):746-748 (2009)journal articl
The safety of transcranial magnetic stimulation with deep brain stimulation instruments
Objectives: Transcranial magnetic stimulation (TMS) has been employed in patients with an implanted deep brain Stimulation (DBS) device. We investigated the safety of TMS using Simulation models with an implanted DBS device. Methods: The DBS lead was inserted into plastic phantoms filled with dilute gelatin showing impedance similar to that of human brain. TMS was performed with three different types of magnetic coil. During TMS (I) electrode movement, (2) temperature change around the lead, and (3) TMS-induced current in various Situations were observed. The amplitude and area of each evoked current were measured to calculate charge density of the evoked current. Results: There was no movement or temperature increase during 0.2 Hz repetitive TMS with 100% stimulus intensity for 1 h. The size of evoked current linearly increased with TMS intensity. The maximum charge density exceeded the safety limit of 30 mu C/cm(2)/phase during Stimulation above the loops of the lead with intensity over 50% using a figure-eight coil. Conclusions: Strong TMS on the looped DBS leads should not be administered to avoid electrical tissue injury. Subcutaneous lead position should be paid enough attention for forthcoming Situations during surgery.ArticlePARKINSONISM & RELATED DISORDERS. 16(2):127-131 (2010)journal articl
DsRNA disrupts airway epithelial barrier integrity through down-regulation of claudin members
The discovery of the most UV-Lya luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities
We report the discovery of BOSS-EUVLG1 at z=2.469, by far the most luminous,
almost un-obscured star-forming galaxy known at any redshift. First classified
as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up
observations with the Gran Telescopio Canarias reveal that its large
luminosity, MUV = -24.40 and log(L_Lya/erg s-1) = 44.0, is due to an intense
burst of star-formation, and not to an AGN or gravitational lensing.
BOSS-EUVLG1 is a compact (reff = 1.2 kpc), young (4-5 Myr) starburst with a
stellar mass log(M*/Msun) = 10.0 +/- 0.1 and a prodigious star formation rate
of ~1000 Msun yr-1. However, it is metal- and dust-poor (12+log(O/H) = 8.13 +/-
0.19, E(B-V) = 0.07, log(LIR/LUV) < -1.2), indicating that we are witnessing
the very early phase of an intense starburst that has had no time to enrich the
ISM. BOSS-EUVLG1 might represent a short-lived (<100 Myrs), yet important phase
of star-forming galaxies at high redshift that has been missed in previous
surveys. Within a galaxy evolutionary scheme, BOSS-EUVLG1 could likely
represent the very initial phases in the evolution of massive quiescent
galaxies, even before the dusty star-forming phase.Comment: 6 pages, 3 figures, 1 table. Accepted for publication in MNRAS
Letter
Scattered X-rays in Obscured Active Galactic Nuclei and their Implications for Geometrical Structure and Evolution
We construct a new sample of 32 obscured active galactic nuclei (AGNs)
selected from the Second XMM-Newton Serendipitous Source Catalogue to
investigate their multiwavelength properties in relation to the "scattering
fraction", the ratio of the soft X-ray flux to the absorption-corrected direct
emission. The sample covers a broad range of the scattering fraction
(0.1%-10%). A quarter of the 32 AGNs have a very low scattering fraction
(smaller than 0.5%), which suggests that they are buried in a geometrically
thick torus with a very small opening angle. We investigate correlations
between the scattering fraction and multiwavelength properties. We find that
AGNs with a small scattering fraction tend to have low [O III]lambda5007/X-ray
luminosity ratios. This result agrees with the expectation that the extent of
the narrow-line region is small because of the small opening angle of the
torus. There is no significant correlation between scattering fraction and
far-infrared luminosity. This implies that a scale height of the torus is not
primarily determined by starburst activity. We also compare scattering fraction
with black hole mass or Eddington ratio and find a weak anti-correlation
between the Eddington ratio and scattering fraction. This implies that more
rapidly growing supermassive black holes tend to have thicker tori.Comment: 13 pages, 10 figures, accepted for publication in Ap
Determination of astrophysical 12N(p,g)13O reaction rate from the 2H(12N, 13O)n reaction and its astrophysical implications
The evolution of massive stars with very low-metallicities depends critically
on the amount of CNO nuclides which they produce. The
N(,\,)O reaction is an important branching point in
the rap-processes, which are believed to be alternative paths to the slow
3 process for producing CNO seed nuclei and thus could change the fate
of massive stars. In the present work, the angular distribution of the
H(N,\,O) proton transfer reaction at =
8.4 MeV has been measured for the first time. Based on the Johnson-Soper
approach, the square of the asymptotic normalization coefficient (ANC) for the
virtual decay of O N + was
extracted to be 3.92 1.47 fm from the measured angular
distribution and utilized to compute the direct component in the
N(,\,)O reaction. The direct astrophysical S-factor at
zero energy was then found to be 0.39 0.15 keV b. By considering the
direct capture into the ground state of O, the resonant capture via the
first excited state of O and their interference, we determined the total
astrophysical S-factors and rates of the N(,\,)O
reaction. The new rate is two orders of magnitude slower than that from the
REACLIB compilation. Our reaction network calculations with the present rate
imply that N()O will only compete successfully with
the decay of N at higher (two orders of magnitude)
densities than initially predicted.Comment: 8 figures, 2 tables, Submitted to Physical Review
Differences in the gas and dust distribution in the transitional disk of a sun-like young star, PDS 70
We present ALMA 0.87 mm continuum, HCO+ J=4--3 emission line, and CO J=3--2
emission line data of the disk of material around the young, Sun-like star PDS
70. These data reveal the existence of a possible two component transitional
disk system with a radial dust gap of 0."2 +/- 0."05, an azimuthal gap in the
HCO+ J=4--3 moment zero map, as well as two bridge-like features in the gas
data. Interestingly these features in the gas disk have no analogue in the dust
disk making them of particular interest. We modeled the dust disk using the
Monte Carlo radiative transfer code HOCHUNK3D (Whitney et al. 2013) using a two
disk components. We find that there is a radial gap that extends from 15-60 au
in all grain sizes which differs from previous work
Cosmochemical Consequences of Particle Trajectories During FU Orionis Outbursts by the Early Sun
The solar nebula is thought to have undergone a number of episodes of FU
Orionis outbursts during its early evolution. We present here the first
calculations of the trajectories of particles in a marginally gravitationally
unstable solar nebula during an FU Orionis outburst, which show that 0.1 to 10
cm-sized particles traverse radial distances of 10 AU or more, inward and
outward, in less than 200 yrs, exposing the particles to temperatures from
60 K to 1500 K. Such trajectories can thus account for the
discovery of refractory particles in comets. Refractory particles should
acquire Wark-Lovering-like rims as they leave the highest temperature regions
of the disk, and these rims should have significant variations in their stable
oxygen isotope ratios. Particles are likely to be heavily modified or destroyed
if they pass within 1 AU of the Sun, and so are only likely to survive if they
formed in the final few FU Orionis outbursts, or were transported to the outer
reaches of the solar system. Calcium, aluminum-rich inclusions (CAIs) from
primitive meteorites are the oldest known solar system objects and have a very
narrow age range. Most CAIs may have formed at the end of the FU Orionis
outbursts phase, with an age range reflecting the period between the last few
outbursts.Comment: 32 pages, 4 figures, in press, EPS
Localization and chiral symmetry in 2+1 flavor domain wall QCD
We present results for the dependence of the residual mass of domain wall
fermions (DWF) on the size of the fifth dimension and its relation to the
density and localization properties of low-lying eigenvectors of the
corresponding hermitian Wilson Dirac operator relevant to simulations of 2+1
flavor domain wall QCD. Using the DBW2 and Iwasaki gauge actions, we generate
ensembles of configurations with a space-time volume and an
extent of 8 in the fifth dimension for the sea quarks. We demonstrate the
existence of a regime where the degree of locality, the size of chiral symmetry
breaking and the rate of topology change can be acceptable for inverse lattice
spacings GeV.Comment: 59 Pages, 23 figures, 1 MPG linke
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