499 research outputs found
Spectrum-Free Estimation of Doppler Velocities Using Ultra-Wideband Radar
A method for estimating Doppler velocities using ultra-wideband radar data is presented. Unlike conventional time-frequency analysis, the proposed method can directly obtain Doppler velocities without searching for peaks in a spectrum. By exploiting closed-form solutions for the Doppler velocities, it avoids the trade-off between time and frequency resolution, thus maintaining high time resolution. Both simulations and measurements are used to evaluate the proposed method versus conventional techniques
New clinically relevant, orthotopic mouse models of human chondrosarcoma with spontaneous metastasis
Chondrosarcoma responds poorly to adjuvant therapy and new, clinically relevant animal models are
required to test targeted therapy. Two human chondrosarcoma cell lines, JJ012 and FS090, were evaluated for proliferation, colony formation, invasion, angiogenesis and osteoclastogenesis. Cell lines were also investigated for VEGF, MMP-2, MMP-9, and RECK
expression. JJ012 and FS090 were injected separately into the mouse tibia intramedullary canal or tibial periosteum.
Animal limbs were measured, and x-rayed for evidence of tumour take and progression. Tibias and lungs were
harvested to determine the presence of tumour and lung metastases. JJ012 demonstrated significantly higher proliferative capacity, invasion, and colony formation in collagen I gel.
JJ012 conditioned medium stimulated endothelial tube formation and osteoclastogenesis with a greater potency than
FS090 conditioned medium, perhaps related to the effects of VEGF and MMP-9. In vivo, tumours formed in intratibial
and periosteal groups injected with JJ012, however no mice injected with FS090 developed tumours. JJ012 periosteal
tumours grew to 3 times the non-injected limb size by 7 weeks, whereas intratibial injected limbs required 10 weeks to achieve a similar tumour size. Sectioned tumour tissue demonstrated features of grade III chondrosarcoma. All JJ012
periosteal tumours (5/5) resulted in lung micro-metastases, while only 2/4 JJ012 intratibial tumours demonstrated
metastases. The established JJ012 models replicate the site, morphology, and many behavioural characteristics of
human chondrosarcoma. Local tumour invasion of bone and spontaneous lung metastasis offer valuable assessment
tools to test the potential of novel agents for future chondrosarcoma therapy
Spin-spiral structures in free-standing Fe(110) monolayers
科研費報告書収録論文(課題番号:16310081/研究代表者:白井正文/ナノ磁性材料におけるスピン構造とそのダイナミクスに関する理論研究
MOIRCS Deep Survey V: A Universal Relation for Stellar Mass and Surface Brightness of Galaxies
We present a universal linear correlation between the stellar mass and
surface brightness (SB) of galaxies at 0.3<z<3, using a deep K-band selected
catalog in the GOODS-North region. The correlation has a nearly constant slope,
independent of redshift and color of galaxies in the rest-z frame. Considering
unresolved compact galaxies, the tight correlation gives a lower boundary of SB
for a given stellar mass; lower SB galaxies are prohibited over the boundary.
The universal slope suggests that the stellar mass in galaxies was build up
over their cosmic histories in a similar manner irrelevant to galaxy mass, as
oppose to the scenario that massive galaxies mainly accumulated their stellar
mass by major merging. In contrast, SB shows a strong dependence on redshift
for a given stellar mass. It evolves as (1+z)^(-2.0~-0.8), in addition to
dimming as (1+z)^4 by the cosmological expansion effect. The brightening
depends on galaxy color and stellar mass. The blue population (rest-frame
U-V<0), which is dominated by young and star-forming galaxies, evolves as
~(1+z)^(-0.8 +-0.3) in the rest-V band. On the other hand, the red population
(U-V>0) and the massive galaxies (M_*>10^(10)M_sun) shows stronger brightening,
(1+z)^(-1.5+-0.1). Based on the comparison with galaxy evolution models, we
find that the phenomena are well explained by the pure luminosity evolution of
galaxies out to z~3.Comment: 10 pages, 9 figures. Accepted for publication in Ap
In vitro and in vivo assays for osteoclast apoptosis
Mature osteoclasts, multinucleated giant cells responsible for bone resorption, are terminally differentiated cells with a short life span. Recently, we have demonstrated that osteoclast apoptosis is regulated by ERK activity and Bcl-2 family member Bim. In this paper, we summarize the methods we used to study osteoclast apoptosis in vitro and in vivo. Using adenovirus and retrovirus vectors, we were able to introduce foreign genes into osteoclasts and examine their effects on osteoclast survival in vitro. In addition, we established the modified methods for in situ hybridization and BrdU labeling of bone sections from mice to study osteoclast survival in vivo. The detailed methods described here could be useful for studying the biological process in bone
MOIRCS Deep Survey. X. Evolution of Quiescent Galaxies as a Function of Stellar Mass at 0.5<z<2.5
We study the evolution of quiescent galaxies at 0.5<z<2.5 as a function of
stellar mass, using very deep NIR imaging data taken with the Multi-Object
Infrared Camera and Spectrograph on the Subaru Telescope in the GOODS-North
region. The deep NIR data allow us to construct a stellar mass-limited sample
of quiescent galaxies down to ~10^{10} Msun even at z~2 for the first time. We
selected quiescent galaxies with age/tau>6 by performing SED fitting of the
multi broad-band photometry from the U to Spitzer 5.8um bands with the
population synthesis model of Bruzual & Charlot (2003) where exponentially
decaying star formation histories are assumed. The number density of quiescent
galaxies increases by a factor of ~3 from 1.0<z<1.5 to 0.5<z<1.0, and by a
factor of ~10 from 1.5<z<2.5 to 0.5<z<1.0, while that of star-forming galaxies
with age/tau<4 increases only by factors of ~2 and ~3 in the same redshift
ranges. At 0.5<z<2.5, the low-mass slope of the stellar mass function of
quiescent galaxies is alpha ~ 0 -- 0.6, which is significantly flatter than
those of star-forming galaxies (alpha ~ -1.3 -- -1.5). As a result, the
fraction of quiescent galaxies in the overall galaxy population increases with
stellar mass in the redshift range. The fraction of quiescent galaxies at
10^{11}-10^{11.5} Msun increases from ~20-30% at z~2 to ~40-60% at z~0.75,
while that at 10^{10}-10^{10.5} Msun increases from <~ 5% to ~15% in the same
redshift range. These results could suggest that the quenching of star
formation had been more effective in more massive galaxies at 1<~z<~2. Such a
mass-dependent quenching could explain the rapid increase of the number density
of ~M* galaxies relative to lower-mass galaxies at z >~ 1-1.5.Comment: 12 pages, 7 figures, accepted for publication in PASJ (Subaru special
issue). Updated to accepted versio
MOIRCS Deep Survey. VII: NIR Morphologies of Star-forming Galaxies at Redshift z~1
We investigate rest-frame near-infrared (NIR) morphologies of a sample of 139
galaxies with M_{s} >= 1 x 10^{10} M_{sun} at z=0.8-1.2 in the GOODS-North
field using our deep NIR imaging data (MOIRCS Deep Survey, MODS). We focus on
Luminous Infrared Galaxies (LIRGs), which dominate high star formation rate
(SFR) density at z~1, in the sample identified by cross-correlating with the
Spitzer/MIPS 24um source catalog. We perform two-dimensional light profile
fitting of the z~1 galaxies in the Ks-band (rest-frame J-band) with a single
component Sersic model. We find that at z~1, ~90% of LIRGs have low Sersic
indices (n<2.5, similar to disk-like galaxies) in the Ks-band, and those
disk-like LIRGs consist of ~60% of the whole disk-like sample above M_{s} >= 3
x 10^{10} M_{sun}. The z~1 disk-like LIRGs are comparable or ~20% small at a
maximum in size compared to local disk-like galaxies in the same stellar mass
range. If we examine rest-frame UV-optical morphologies using the HST/ACS
images, the rest-frame B-band sizes of the z~1 disk-like galaxies are
comparable to those of the local disk-like galaxies as reported by previous
studies on size evolution of disk-like galaxies in the rest-frame optical band.
Measuring color gradients (galaxy sizes as a function of wavelength) of the z~1
and local disk-like galaxies, we find that the z~1 disk-like galaxies have 3-5
times steeper color gradient than the local ones. Our results indicate that (i)
more than a half of relatively massive disk-like galaxies at z~1 are in violent
star formation epochs observed as LIRGs, and also (ii) most of those LIRGs are
constructing their fundamental disk structure vigorously. The high SFR density
in the universe at z~1 may be dominated by such star formation in disk region
in massive galaxies.Comment: 16 pages, 15 figures, accepted for publication in PASJ. Catalog data
will be available at http://astr.tohoku.ac.jp/MODS/wiki/index.php soo
Assembly of Massive Galaxies in a High-z Protocluster
We present the results of wide-field deep JHK imaging of the SSA22 field
using MOIRCS instrument equipped with Subaru telescope. The observed field is
112 arcmin^2 in area, which covers the z=3.1 protocluster characterized by the
overdensities of Ly Alpha emitters (LAEs) and Ly Alpha Blobs (LABs). The 5
sigma limiting magnitude is K_{AB} = 24.3. We extract the potential
protocluster members from the K-selected sample by using the multi-band
photometric-redshift selection as well as the simple color cut for distant red
galaxies (DRGs; J-K_{AB}>1.4). The surface number density of DRGs in our
observed fields shows clear excess compared with those in the blank fields, and
the location of the densest area whose projected overdensity is twice the
average coincides with the large-scale density peak of LAEs. We also found that
K-band counterparts with z_{phot} = 3.1 are detected for 75% (15/20) of the
LABs within their Ly Alpha halo, and the 40 % (8/20) of LABs have multiple
components, which gives a direct evidence of the hierarchical multiple merging
in galaxy formation. The stellar mass ofLABs correlates with their luminosity,
isophotal area, and the Ly Alpha velocity widths, implying that the physical
scale and the dynamical motion of Ly Alpha emission are closely related to
their previous star-formation activities. Highly dust-obscured galaxies such as
hyper extremely red objects (HEROs; J-K_{AB}>2.1) and plausible K-band
counterparts of submillimeter sources are also populated in the high density
region.Comment: 21pages, accepted for publication in Astrophysical Journa
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