28 research outputs found
Long-Term Density Trend in the Mesosphere and Lower Thermosphere from Occultations of the Crab Nebula with X-Ray Astronomy Satellites
We present long-term density trends of the Earth's upper atmosphere at
altitudes between 71 and 116 km, based on atmospheric occultations of the Crab
Nebula observed with X-ray astronomy satellites, ASCA, RXTE, Suzaku, NuSTAR,
and Hitomi. The combination of the five satellites provides a time period of 28
yr from 1994 to 2022. To suppress seasonal and latitudinal variations, we
concentrate on the data taken in autumn (49< doy <111) and spring (235< doy
<297) in the northern hemisphere with latitudes of 0--40 degrees. With this
constraint, local times are automatically limited either around noon or
midnight. We obtain four sets (two seasons times two local times) of density
trends at each altitude layer. We take into account variations due to a linear
trend and the 11-yr solar cycle using linear regression techniques. Because we
do not see significant differences among the four trends, we combine them to
provide a single vertical profile of trend slopes. We find a negative density
trend of roughly -5 %/decade at every altitude. This is in reasonable agreement
with inferences from settling rate of the upper atmosphere. In the 100--110 km
altitude, we found an exceptionally high density decline of about -12 %/decade.
This peak may be the first observational evidence for strong cooling due to
water vapor and ozone near 110 km, which was first identified in a numerical
simulation by Akmaev et al. (2006). Further observations and numerical
simulations with suitable input parameters are needed to establish this
feature.Comment: 38 pages, 9 figures, accepted for publication in Journal of
Geophysical Research - Space Physic
A Spectral Study of the Black Hole Candidate XTE J1752-223 in the High/Soft State with MAXI, Suzaku and Swift
We report on the X-ray spectral analysis of the black hole candidate XTE\
J1752--223 in the 2009--2010 outburst, utilizing data obtained with the
MAXI/Gas Slit Camera (GSC), the Swift/XRT, and Suzaku, which work
complementarily. As already reported by Nakahira et al. (2010) MAXI monitored
the source continuously throughout the entire outburst for about eight months.
All the MAXI/GSC energy spectra in the high/soft state lasting for 2 months are
well represented by a multi-color disk plus power-law model. The innermost disk
temperature changed from 0.7 keV to 0.4 keV and the disk flux
decreased by an order of magnitude. Nevertheless, the innermost radius is
constant at 41 km, where is the
source distance in units of 3.5 kpc and the inclination. The multi-color
disk parameters obtained with the MAXI/GSC are consistent with those with the
Swift/XRT and Suzaku. The Suzaku data also suggests a possibility that the disk
emission is slightly Comptonized, which could account for broad iron-K features
reported previously. Assuming that the obtained innermost radius represents the
innermost stable circular orbit for a non-rotating black hole, we estimate the
mass of the black hole to be 5.510.28 , where the correction for the stress-free inner boundary condition
and color hardening factor of 1.7 are taken into account. If the inclination is
less than 49 as suggested from the radio monitoring of transient jets
and the soft-to-hard transition in 2010 April occurred at 1--4% of Eddignton
luminosity, the fitting of the Suzaku spectra with a relativistic
accretion-disk model derives constraints on the mass and the distance to be
3.1--55 and 2.3--22 {\rm kpc}, respectively. This confirms that the
compact object in XTE J1752--223 is a black hole.Comment: 12 pages including 7 figures and 4 tables, accepted for publication
in PAS
Characterization of Oligosaccharide Ligands Expressed on SW1116 Cells Recognized by Mannan-binding Protein-A HIGHLY FUCOSYLATED POLYLACTOSAMINE TYPE N-GLYCAN
Radiofrequency ablation in a porcine liver model: Effects of transcatheter arterial embolization with iodized oil on ablation time, maximum output, and coagulation diameter as well as angiographic characteristics
Base-Resolution Methylome of Retinal Pigment Epithelial Cells Used in the First Trial of Human Induced Pluripotent Stem Cell-Based Autologous Transplantation
The first-in-human trial of induced pluripotent stem cell (iPSC)-based autologous transplantation was successfully performed on a female patient with age-related macular degeneration. Here we delineated the base-resolution methylome of the iPSC-derived retinal pigment epithelium (iRPE) used in this trial. The methylome of iRPE closely resembled that of native RPE (nRPE), although partially methylated domains (PMDs) emerged in iRPE but not nRPE. Most differentially methylated regions between iRPE and nRPE appeared to originate from (de)methylation errors during differentiation, whereas errors at reprogramming resulted in aberrant genomic imprinting and X chromosome reactivation. Moreover, non-CpG methylation was prominent in nRPE but not iRPE. Intriguingly, xenotransplantation to mouse remodeled the iRPE methylome to demethylate a subset of suppressed genes and accumulate non-CpG methylation, but failed to resolve PMDs and hypermethylated CpG islands. Although the impacts of these alterations remain elusive, our findings should provide a useful guide for methylome analyses of other iPSC-derived cells