166 research outputs found
Aligned Molecular Clouds towards SS433 and L=348.5 degrees; Possible Evidence for Galactic "Vapor Trail" Created by Relativistic Jet
We have carried out a detailed analysis of the NANTEN 12CO(J=1-0) dataset in
two large areas of ~25 square degrees towards SS433 (l~40 degree) and of ~18
square degrees towards l~348.5 degree, respectively. We have discovered two
groups of remarkably aligned molecular clouds at |b|~1--5 degree in the two
regions. In SS433, we have detected 10 clouds in total, which are well aligned
nearly along the axis of the X-ray jet emanating from SS433. These clouds have
similar line-of-sight velocities of 42--56 km s^-1 and the total projected
length of the feature is ~300 pc, three times larger than that of the X-ray
jet, at a distance of 3 kpc. Towards l~348.5 degree, we have detected four
clouds named as MJG348.5 at line-of-sight velocities of -80 -- -95 km s^-1 in
V_LSR, which also show alignment nearly perpendicular to the Galactic plane.
The total length of the feature is ~400 pc at a kinematic distance of 6 kpc. In
the both cases, the CO clouds are distributed at high galactic latitudes where
such clouds are very rare. In addition, their alignments and coincidence in
velocity should be even rarer, suggesting that they are physically associated.
We tested a few possibilities to explain these clouds, including protostellar
outflows, supershells, and interactions with energetic jets. Among them, a
favorable scenario is that the interaction between relativistic jet and the
interstellar medium induced the formation of molecular clouds over the last
~10^5-6 yrs. It is suggested that the timescale of the relativistic jet may be
considerably larger, in the order of 10^5-6 yrs, than previously thought in
SS433. The driving engine of the jet is obviously SS433 itself in SS433,
although the engine is not yet identified in MJG348.5 among possible several
candidates detected in the X-rays and TeV gamma rays.Comment: 29 pages, 10 figures, already published in PASJ, 2008,60, 71
Possible superconductivity above 25 K in single crystalline Co-doped BaFeAs
We present superconducting properties of single crystalline
Ba(FeCo)As by measuring magnetization, resistivity,
upper critical field, Hall coefficient, and magneto-optical images. The
magnetization measurements reveal fish-tail hysteresis loop at high
temperatures and relatively high critical current density above
A/cm at low temperatures. Upper critical field determined by resistive
transition is anisotropic with anisotropic parameter 3.5. Hall effect
measurements indicate that Ba(FeCo)As is a
multiband system and the mobility of electron is dominant. The magneto-optical
imaging reveals prominent Bean-like penetration of vortices although there is a
slight inhomogeneity in a sample. Moreover, we find a distinct
superconductivity above 25 K, which leads us to speculate that higher
transition temperature can be realized by fine tuning Co-doping level.Comment: 4 pages, 5 figure
X-ray Diffraction Study of Spontaneous Strain in Fe-Pnictide Superconductor, NdFeAsO0.89F0.11
The lattice parameters of a Nd 1111 Fe-pnictide superconductor, NdFeAsO0.89F0.11, were accurately measured using X-ray diffraction between 20 K and 280 K. A very small change in the lattice parameter could be detected in the superconducting phase. This change can be attributed to a spontaneous strain generated in the superconducting phase by the coupling between a superconducting order parameter and the strain. The present results are compared with the thermal expansion coefficients of Ba(Fe1âxCox)2As2, in addition to the previous lattice parameter measurements of YBa2Cu3O6.5, MgB2, La1.85Sr0.15CuO4, and Ba0.6K0.4BiO3
X-ray diffraction study of spontaneous strain in superconducting Ba0.6 K0.4 BiO3
éæȹ性ćŠçć·„ç 究ćæ°ç©ç§ćŠçł»The lattice parameter of Ba0.6 K0.4 BiO3, which is a well-studied conventional superconductor, was measured by the X-ray Rietveld method between 10 K and room temperature. A very small change in the lattice parameter could be detected in the superconducting phase. The change could be attributed to a spontaneous strain generated in the superconducting phase by the coupling between a superconducting order parameter and the strain. Previously published data on Y Ba2 Cu3 O6.5 and MgB2 were analyzed, and the present results were compared with our previously obtained results on La1.85 Sr0.15 CuO4. It was concluded that this coupling phenomenon is common to all superconductors. © 2010 Elsevier Ltd. All rights reserved
Videofluorographic Evaluation of Mastication and Swallowing of Japanese Udon Noodles and White Rice
A videofluorographic (VF) swallowing study was performed on 22 healthy volunteers to observe the complete mastication and swallowing phases for Japanese udon noodles and white rice. The hardness, stickiness, and cohesiveness of food samples were measured using a food texture analyzing system. VF images were acquired using a versatile fluoroscopic unit and barium sulfate was used as a contrast medium. Udon noodles had a harder and smoother food texture than white rice. Fewer chewing movements and more stage 2 transport were seen during the consumption of udon noodles than for white rice
Effect of anisotropic impurity scattering in superconductors
We discuss the weak-coupling BCS theory of a superconductor with the
impurities, accounting for their anisotropic momentum-dependent potential. The
impurity scattering process is considered in the t-matrix approximation and its
influence on the superconducting critical temperature is studied in the Born
and unitary limit for a d- and (d+s)-wave superconductors. We observe a
significant dependence of the pair-breaking strength on the symmetry of the
scattering potential and classify the impurity potentials according to their
ability to alter T_c. A good agreement with the experimental data for Zn doping
and oxygen irradiation in the overdoped cuprates is found.Comment: 31 pages, RevTex, 15 PostScript figure
Photon Dominated Regions in NGC 3603
Aims: We aim at deriving the excitation conditions of the interstellar gas as
well as the local FUV intensities in the molecular cloud surrounding NGC 3603
to get a coherent picture of how the gas is energized by the central stars.
Methods: The NANTEN2-4m submillimeter antenna is used to map the [CI] 1-0, 2-1
and CO 4-3, 7-6 lines in a 2' x 2' region around the young OB cluster NGC 3603
YC. These data are combined with C18O 2-1 data, HIRES-processed IRAS 60 and 100
micron maps of the FIR continuum, and Spitzer/IRAC maps. Results: The NANTEN2
observations show the presence of two molecular clumps located south-east and
south-west of the cluster and confirm the overall structure already found by
previous CS and C18O observations. We find a slight position offset of the peak
intensity of CO and [CI], and the atomic carbon appears to be further extended
compared to the molecular material. We used the HIRES far-infrared dust data to
derive a map of the FUV field heating the dust. We constrain the FUV field to
values of \chi = 3 - 6 \times 10^3 in units of the Draine field across the
clouds. Approximately 0.2 to 0.3 % of the total FUV energy is re-emitted in the
[CII] 158 {\mu}m cooling line observed by ISO. Applying LTE and escape
probability calculations, we derive temperatures (TMM1 = 43 K, TMM2 = 47 K),
column densities (N(MM1) = 0.9 \times 10^22 cm^-2, N(MM2) = 2.5 \times 10^22
cm^-2) and densities (n(MM1) = 3 \times 10^3 cm^-3, n(MM2) = 10^3 -10^4 cm^-3)
for the two observed molecular clumps MM1 and MM2. Conclusions: The cluster is
strongly interacting with the ambient molecular cloud, governing its structure
and physical conditions. A stability analysis shows the existence of
gravitationally collapsing gas clumps which should lead to star formation.
Embedded IR sources have already been observed in the outskirts of the
molecular cloud and seem to support our conclusions.Comment: 13 pages, 10 figures, accepted for publication by A&
Upregulation of P2Y2 receptors by retinoids in normal human epidermal keratinocytes
Retinoids, vitamin A derivatives, are important regulators of the growth and differentiation of skin cells. Although retinoids are therapeutically used for several skin ailments, little is known about their effects on P2 receptors, known to be involved in various functions in the skin. DNA array analysis showed that treatment of normal human epidermal keratinocytes (NHEKs) with all-trans-retinoic acid (ATRA), an agonist to RAR (retinoic acid receptor), enhanced the expression of mRNA for the P2Y2 receptor, a metabotropic P2 receptor that is known to be involved in the proliferation of the epidermis. The expression of other P2 receptors in NHEKs was not affected by ATRA. ATRA increased the mRNA for the P2Y2 receptor in a concentration-dependent fashion (1Â nM to 1Â ÎŒM). Am80, a synthesized agonist to RAR, showed a similar enhancement, whereas 9-cis-retinoic acid (9-cisRA), an agonist to RXR (retinoid X receptor), enhanced P2Y2 gene expression to a lesser extent. Ca2+ imaging analysis showed that ATRA also increased the function of P2Y2 receptors in NHEKs. Retinoids are known to enhance the turnover of the epidermis by increasing both proliferation and terminal differentiation. The DNA microarray analysis also revealed that ATRA upregulates various genes involved in the differentiation of NHEKs. Our present results suggest that retinoids, at least in part, exert their proliferative effects by upregulating P2Y2 receptors in NHEKs. This effect of retinoids may be closely related to their therapeutic effect against various ailments or aging events in skins such as over-keratinization, pigmentation and re-modeling
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