133 research outputs found
Discovery of a Strongly Lensed Galaxy at z=3.9 behind a z=0.83 Galaxy Cluster
We report the discovery and spectroscopic confirmation of three
gravitationally-lensed images of a galaxy at z=3.9 in the background of a
distant, rich cluster of galaxies at z=0.83, on the basis of observations with
Faint Object Camera And Spectrograph (FOCAS) on the Subaru telescope. We
construct a simple lens model of the cluster mass distribution based on Jee et
al.'s weak lensing mass estimates from deep, high-resolution images by Advanced
Camera for Surveys (ACS) on the Hubble Space Telescope. The lens model can
account simultaneously for the observed image configuration and the flux ratio
of the closer pair located close to the critical curve. The parities of the
three images are also consistent with the lensing hypothesis. Since this galaxy
is apparently bright (i'_{AB} \sim 23.7) for its redshift due to the
magnification, it serves as a good high redshift target on which we can make
extensive and detailed studies based on multi-wavelength imaging and
spectroscopy.Comment: 4 pages, 3 figures, 1 table, accepted for publication in PAS
Standard and limitation of intraoperative monitoring of the visual evoked potential
Visual evoked potential (VEP) has been installed as one of the intraoperative visual function monitoring. It remains unclear, however, whether intraoperative VEP monitoring facilitates as a real time visual function monitoring with satisfactory effectiveness and sensitivity. To evaluate this, relationships between VEP waveform changes and postoperative visual function were analysed retrospectively. Intraoperative VEP monitoring was carried out for 106 sides (eyes) in 53 surgeries, including two intraorbital, 36 parasellar and 15 cortical lesions in Shinshu University Hospital under total intravenous anaesthesia. Red light flash stimulation was provided to each eye independently. VEP recording and postoperative visual function were analysed. In 103 out of 106 sides (97%), steady VEP monitoring was recorded. Stable VEP was acquired from eyes having corrected visual acuity greater than 0.4. VEP was not recorded in one side with corrected visual acuity of 0.3 and two sides in whom sevoflurane was used incidentally for anaesthesia. Transient VEP decrease was observed in three sides, but visual function was preserved. Permanent VEP decrease was seen in seven sides, which presented visual impairment postoperatively. In one side, visual acuity improved but minor visual field defect was encountered postoperatively, though VEP unchanged throughout the surgery. Intraoperative monitoring of VEP predicts postoperative visual function: reversible change in VEP means visual function to be preserved. Visual field defect without decrease in the visual acuity may not be predicted by VEP monitoring. Intraoperative VEP monitoring will be mandatory for surgeries harbouring a risk of visual impairment.ArticleACTA NEUROCHIRURGICA. 152(4):643-648 (2010)journal articl
Expression-Based Genome-Wide Association Study Links Vitamin D-Binding Protein With Autoantigenicity in Type 1 Diabetes.
Type 1 diabetes (T1D) is caused by autoreactive T cells that recognize pancreatic islet antigens and destroy insulin-producing β-cells. This attack results from a breakdown in tolerance for self-antigens, which is controlled by ectopic antigen expression in the thymus and pancreatic lymph nodes (PLNs). The autoantigens known to be involved include a set of islet proteins, such as insulin, GAD65, IA-2, and ZnT8. In an attempt to identify additional antigenic proteins, we performed an expression-based genome-wide association study using microarray data from 118 arrays of the thymus and PLNs of T1D mice. We ranked all 16,089 protein-coding genes by the likelihood of finding repeated differential expression and the degree of tissue specificity for pancreatic islets. The top autoantigen candidate was vitamin D-binding protein (VDBP). T-cell proliferation assays showed stronger T-cell reactivity to VDBP compared with control stimulations. Higher levels and frequencies of serum anti-VDBP autoantibodies (VDBP-Abs) were identified in patients with T1D (n = 331) than in healthy control subjects (n = 77). Serum vitamin D levels were negatively correlated with VDBP-Ab levels in patients in whom T1D developed during the winter. Immunohistochemical localization revealed that VDBP was specifically expressed in α-cells of pancreatic islets. We propose that VDBP could be an autoantigen in T1D
On the origin of the Tully-Fisher relation
We discuss the origin of the Tully-Fisher (TF) relation using the
-body/SPH method, which includes cooling, star formation and stellar
feedback of energy, mass and metals. We consider initially rotating overdense
spheres, and trace formation processes of disk galaxies from to in
the Cold Dark Matter (CDM) cosmology. To clarify the origin of the TF relation,
we simulate formation of 14 galaxies with different masses and spin parameters,
and compute observable values, such as the total magnitude and the line-width.
We find that the simulated galaxies reproduce the slope and scatter of the TF
relation: the slope is originated in the difference of total galactic masses,
and the scatter is produced by the difference of initial spin parameters. As
well as the TF relation, observed features of spiral galaxies, such as the
exponential light-profile and the flat rotation curve, are reproduced in our
simulations, which were assumed {\it a priori} in past semi-analytical
approaches.Comment: 11 pages, including 6 figures, submitted to Ap
FitSNPs: highly differentially expressed genes are more likely to have variants associated with disease
Differential expressed genes are more likely to have variants associated with disease. A new tool, fitSNP, prioritizes candidate SNPs from association studies
Gliosarcoma arising from a fibrillary astrocytoma
We report a 67-year-old woman who was diagnosed with a gliosarcoma at a second operation after diagnosis of a fibrillary astrocytoma 5 months previously. Initially, she underwent a CT-guided stereotactic biopsy. Histological examination showed fibrillary astrocytoma (World Health Organization [WHO] grade II). Loss of heterozygosity (LOH) on 1 p, 10q, and 19q was not detected. She received chemotherapy, but no radiotherapy. Five months after the biopsy, MRI revealed rapid tumor growth. Tissue obtained from partial removal of the tumor revealed gliosarcoma (WHO grade IV), and LOH on 10q and 19q was detected. The history, histopathology, and genetic alterations of this patient are discussed.ArticleJOURNAL OF CLINICAL NEUROSCIENCE. 18(9):1251-1254 (2011)journal articl
A Unified Scaling Law in Spiral Galaxies
We investigate the origin of a unified scaling relation in spiral galaxies.
Observed spiral galaxies are spread on a plane in the
three-dimensionallogarithmic space of luminosity L, radius R and rotation
velocity V. The plane is expressed as in I-passband,
where is a constant. On the plane, observed galaxies are distributed
in an elongated region which looks like the shape of a surfboard. The
well-known scaling relations, L-V (Tully-Fisher relation), V-R (also the
Tully-Fisher relation) and R-L (Freeman's law), can be understood as oblique
projections of the surfboard-like plane into 2-D spaces. This unified
interpretation of the known scaling relations should be a clue to understand
the physical origin of all the relations consistently. Furthermore, this
interpretation can also explain why previous studies could not find any
correlation between TF residuals and radius.
In order to clarify the origin of this plane, we simulate formation and
evolution of spiral galaxies with the N-body/SPH method, including cooling,
star formation and stellar feedback. Initial conditions are set to isolated 14
spheres with two free parameters, such as mass and angular momentum. The CDM
(h=0.5, ) cosmology is considered as a test case. The simulations
provide the following two conclusions: (a) The slope of the plane is well
reproduced but the zero-point is not. This zero-point discrepancy could be
solved in a low density ($\Omega_00.5) cosmology.
(b) The surfboard-shaped plane can be explained by the control of galactic mass
and angular momentum.Comment: Accepted for publication in ApJ Letters. 6 pages including 2 figure
The Build-up of the Colour-Magnitude Relation as a Function of Environment
We discuss the environmental dependence of galaxy evolution based on deep
panoramic imaging of two distant clusters taken with Suprime-Cam as part of the
PISCES project. By combining with the SDSS data as a local counterpart for
comparison, we construct a large sample of galaxies that spans wide ranges in
environment, time, and stellar mass (or luminosity). We find that colours of
galaxies, especially those of faint galaxies (), change from blue
to red at a break density as we go to denser regions. Based on local and global
densities of galaxies, we classify three environments: field, groups, and
clusters. We show that the cluster colour-magnitude relation is already built
at . In contrast to this, the bright-end of the field colour-magnitude
relation has been vigorously built all the way down to the present-day and the
build-up at the faint-end has not started yet. A possible interpretation of
these results is that galaxies evolve in the 'down-sizing' fashion. That is,
massive galaxies complete their star formation first and the truncation of star
formation is propagated to smaller objects as time progresses. This trend is
likely to depend on environment since the build-up of the colour-magnitude
relation is delayed in lower-density environments. Therefore, we may suggest
that the evolution of galaxies took place earliest in massive galaxies and in
high density regions, and it is delayed in less massive galaxies and in lower
density regions.Comment: 23pages, 19 figures, accepted for publication in MNRA
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