77 research outputs found
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Studies on Synthetic Pyrethroid. (XI) : Another Evidence for the trans-Configuration of a,o-Dimethylsorbic Acid
Age-Specific Prevalence of Glaucoma is Determined by the Presence of Refractive Errors Among Japanese Workers
To develop appropriate glaucoma mass screening programs for occupational health among Japanese workers, we estimated the prevalence of glaucoma and the increase rate by age. A total of 10,579 Japanese general workers (men/women = 9292/1287) underwent frequency doubling technology (FDT) perimetry testing. Visual field abnormalities (VFA) were identified by the FDT-based glaucoma screening protocol (FDT-VFA). Subjects with FDT-VFA were ophthalmologically diagnosed and classified as "normal," "glaucomatous VFA" (preperimetric, suspicious, and definitive glaucoma) or "other ocular diseases." Prevalence of FDT-VFA and positive predictive values for "glaucomatous VFA" and "definitive glaucoma" were calculated by five-year age intervals, and then the prevalence of "glaucomatous VFA" and "definitive glaucoma" in each age interval was estimated. Prevalence of "glaucomatous VFA" and "definitive glaucoma" in workers younger than 30 years old was approximately 1.5% and 0.5%, respectively. Interestingly, the increase in prevalence of glaucoma by age was significantly different between workers with and without refractive errors (RE). From ages 30 to 55 years, the estimated prevalence of "definitive glaucoma" linearly increased with a regression coefficient (%/age in years) that was 2.5-fold higher in subjects with RE than in those without RE {regression coefficient = 0.131 [95% confidence interval (CI) = 0.109, 0.152; R2 = 0.980]vs. 0.047 [95% CI = 0.026, 0.068; R2 = 0.869]for subjects with RE vs. those without RE, respectively}. Further, among workers older than 55 years, the prevalence of glaucoma continued increasing in workers with RE, whereas it plateaued in those without RE. From these estimates, we propose that FDT testing should be conducted as follows: 1) once in workers under the age of 30 years, 2) according to both age and the presence of RE in 30-55 years old, and 3) by age only in those over 55 years old
Suzaku Observations of SGR 1900+14 and SGR 1806-20
Spectral and timing studies of Suzaku ToO observations of two SGRs, 1900+14
and 1806-20, are presented. The X-ray quiescent emission spectra were well
fitted by a two blackbody function or a blackbody plus a power law model. The
non-thermal hard component discovered by INTEGRAL was detected by the PIN
diodes and its spectrum was reproduced by the power law model reported by
INTEGRAL. The XIS detected periodicity P = 5.1998+/-0.0002 s for SGR 1900+14
and P = 7.6022+/-0.0007 s for SGR 1806-20. The pulsed fraction was related to
the burst activity for SGR 1900+14.Comment: 8 pages, 3 figures, Accepted for publication in PASJ (Suzaku 3rd
special issue
Spectral evolution of GRB 060904A observed with Swift and Suzaku -- Possibility of Inefficient Electron Acceleration
We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku
satellites. We found rapid spectral softening during both the prompt tail phase
and the decline phase of an X-ray flare in the BAT and XRT data. The observed
spectra were fit by power-law photon indices which rapidly changed from to within a few hundred
seconds in the prompt tail. This is one of the steepest X-ray spectra ever
observed, making it quite difficult to explain by simple electron acceleration
and synchrotron radiation. Then, we applied an alternative spectral fitting
using a broken power-law with exponential cutoff (BPEC) model. It is valid to
consider the situation that the cutoff energy is equivalent to the synchrotron
frequency of the maximum energy electrons in their energy distribution. Since
the spectral cutoff appears in the soft X-ray band, we conclude the electron
acceleration has been inefficient in the internal shocks of GRB 060904A. These
cutoff spectra suddenly disappeared at the transition time from the prompt tail
phase to the shallow decay one. After that, typical afterglow spectra with the
photon indices of 2.0 are continuously and preciously monitored by both XRT and
Suzaku/XIS up to 1 day since the burst trigger time. We could successfully
trace the temporal history of two characteristic break energies (peak energy
and cutoff energy) and they show the time dependence of while the following afterglow spectra are quite stable. This fact
indicates that the emitting material of prompt tail is due to completely
different dynamics from the shallow decay component. Therefore we conclude the
emission sites of two distinct phenomena obviously differ from each other.Comment: 19 pages, 9 figures, accepted for publication in PASJ (Suzaku 2nd
Special Issue
The ASTRO-H X-ray Observatory
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly
successful X-ray missions initiated by the Institute of Space and Astronautical
Science (ISAS). ASTRO-H will investigate the physics of the high-energy
universe via a suite of four instruments, covering a very wide energy range,
from 0.3 keV to 600 keV. These instruments include a high-resolution,
high-throughput spectrometer sensitive over 0.3-2 keV with high spectral
resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in
the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers
covering 5-80 keV, located in the focal plane of multilayer-coated, focusing
hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12
keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and
a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the
40-600 keV band. The simultaneous broad bandpass, coupled with high spectral
resolution, will enable the pursuit of a wide variety of important science
themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to
Gamma Ray
The Quiescent Intracluster Medium in the Core of the Perseus Cluster
Clusters of galaxies are the most massive gravitationally-bound objects in
the Universe and are still forming. They are thus important probes of
cosmological parameters and a host of astrophysical processes. Knowledge of the
dynamics of the pervasive hot gas, which dominates in mass over stars in a
cluster, is a crucial missing ingredient. It can enable new insights into
mechanical energy injection by the central supermassive black hole and the use
of hydrostatic equilibrium for the determination of cluster masses. X-rays from
the core of the Perseus cluster are emitted by the 50 million K diffuse hot
plasma filling its gravitational potential well. The Active Galactic Nucleus of
the central galaxy NGC1275 is pumping jetted energy into the surrounding
intracluster medium, creating buoyant bubbles filled with relativistic plasma.
These likely induce motions in the intracluster medium and heat the inner gas
preventing runaway radiative cooling; a process known as Active Galactic
Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus
cluster core, which reveal a remarkably quiescent atmosphere where the gas has
a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from
the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s
is found across the 60 kpc image of the cluster core. Turbulent pressure
support in the gas is 4% or less of the thermodynamic pressure, with large
scale shear at most doubling that estimate. We infer that total cluster masses
determined from hydrostatic equilibrium in the central regions need little
correction for turbulent pressure.Comment: 31 pages, 11 Figs, published in Nature July
Hitomi (ASTRO-H) X-ray Astronomy Satellite
The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at Eāā>āā2āākeV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month
The role of sulfoglucuronosyl glycosphingolipids in the pathogenesis of monoclonal IgM paraproteinemia and peripheral neuropathy
In IgM paraproteinemia and peripheral neuropathy, IgM M-protein secretion by B cells leads to a T helper cell response, suggesting that it is antibody-mediated autoimmune disease involving carbohydrate epitopes in myelin sheaths. An immune response against sulfoglucuronosyl glycosphingolipids (SGGLs) is presumed to participate in demyelination or axonal degeneration in the peripheral nervous system (PNS). SGGLs contain a 3-sulfoglucuronic acid residue that interacts with anti-myelin-associated glycoprotein (MAG) and the monoclonal antibody anti-HNK-1. Immunization of animals with sulfoglucuronosyl paragloboside (SGPG) induced anti-SGPG antibodies and sensory neuropathy, which closely resembles the human disease. These animal models might help to understand the disease mechanism and lead to more specific therapeutic strategies. In an in vitro study, destruction or malfunction of the blood-nerve barrier (BNB) was found, resulting in the leakage of circulating antibodies into the PNS parenchyma, which may be considered as the initial key step for development of disease
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