166 research outputs found

    Aligned Molecular Clouds towards SS433 and L=348.5 degrees; Possible Evidence for Galactic "Vapor Trail" Created by Relativistic Jet

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    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 BaFe2_{2}As2_{2}

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    We present superconducting properties of single crystalline Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2} 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 Jc=105J_{c}=10^{5} A/cm2^{2} at low temperatures. Upper critical field determined by resistive transition is anisotropic with anisotropic parameter ∌\sim 3.5. Hall effect measurements indicate that Ba(Fe0.9_{0.9}Co0.1_{0.1})2_{2}As2_{2} 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

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    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(Fe1−xCox)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

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    金æČąć€§ć­Šç†ć·„ç ”ç©¶ćŸŸæ•°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

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    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

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    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

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    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

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    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 (1 nM to 1 ΌM). 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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