Enhancement of critical current density and vortex activation energy in proton-irradiated Co-doped BaFe2As2

The effect of proton irradiation in Ba(Fe0.93Co0.07)2As2 single crystals is reported. We analyze temperature dependence of current density and normalized flux relaxation rate in the framework of collective creep model. Glassy exponent and barrier height for flux creep are directly determined by Maley's method. Our model functions for barrier height and critical current density in the absence of flux creep are explained by the superposition of \deltaTc- and \deltal-pinning. We also approach true critical current density by means of generalized inversion scheme, and the obtained result is in reasonable agreement with our model function. Proton irradiation effect on temperature dependence of current density and normalized relaxation rate can be summarized as doubling of barrier height at the beginning of flux creep.Comment: 6 pages, 4 figures. To be published in Phys. Rev.

Magnetic and transport properties of iron-platinum arsenide Ca10(Pt4-{\delta}As8)(Fe2-xPtxAs2)5 single crystal

We report superconducting properties of single crystalline Ca10(Pt4-{\delta}As8)(Fe2-xPtxAs2)5 by X-ray diffraction, magnetization, resistivity, and magneto-optical imaging measurements. The magnetization measurements reveal fish-tail hysteresis loop and relatively high critical current density Jc ~ 0.8\times105 A/cm2 at low temperatures. The exponential temperature dependence of Jc, which arises from nonlinear effective flux-creep activation energy, has been observed. Upper critical field determined by resistive transition shows a relatively large anisotropy. The magneto-optical images reveal homogenous current flow within the crystal.Comment: 6 pages, 6 figures, Accepted for publication in Phys. Rev.

Transport and magnetic properties of Co-doped BaFe_{2}As_{2} epitaxial thin films

We report resistivity, Hall coefficient, current-voltage characteristics, and magneto-optical imaging measurements of epitaxial Co-doped BaFe_{2}As_{2} thin films deposited on MgO(001) substrate. The Hall resistivity of the films has a substantial contribution arising from anomalous Hall effect of ferromagnetic components. The critical current density (J_{c}) of the films is ~2 MA/cm^{2} at low temperatures. Differential magneto-optical images of the remanent state give similar J_{c} values and also exhibit presence of extended defects in the film.Comment: 9 pages, 4 figure

重症慢性肝疾患における高γク口ブリン血症の意義 : とくに血清グ口プリン/IgG とICG除去能との相聞に関連して

BACKGROUND/AIMS:Although hyperglobulinemia is frequently detected in severe chronic liver diseases (CLD) such as liver cirrhosis (LC), the mechanism for this is still uncertain. Hyperglobulinemia may represent a functional aspect of the liver.METHODOLOGY: The correlation between serum globulin (GLB) level and each of various liver function tests including the indocyanine green (ICG) retention rate at 15 min (ICGR15) was studied using 146 patients with liver dysfunction. The correlations among GLB, IgG and ICGR15 were also studied in other 32 patients with LC, in whom the glycosylation pattern of IgG was determined by enzyme-linked immunosorbent assay to detect terminal galactose (Gal) and neuraminic acid (NA) using biotinylated lectins.RESULTS:GLB level was predominantly correlated with ICGR15 (r = 0.449) among various liver function tests in 146 patients with liver dysfunction. In the 32 patients with LC, strong positive correlations between GLB and IgG (r = 0.875), between GLB and ICGR15 (r = 0.435), and between IgG and ICGR15 (r = 0.557) were evident. The glycosylation pattern of IgG showed that the proportions of both Gal and NA were inversely correlated with serum IgG levels (r = -0.516 and -0.390, respectively) in these patients. Significant decreases of the proportions were found in patients with IgG elevation (> 20 g/L, n = 13).CONCLUSIONS:The correlation between GLB and ICGR15 suggested that hyperglobulinemia is related to a common dysfunction estimated by ICG clearance, which represents mainly the liver's blood flow and removal capacity. The removal of immunoglobulins by the liver may be impaired in patients with severe liver dysfunction because the liver is a major catabolic site for immunoglobulins. The glycation pattern suggested that the proportions of asialo IgG and agalactosyl IgG were increased in the LC patients with IgG elevation possibly by deficient receptor-mediated removal in the liver. Although further investigations will be needed, hyperglobulinemia could be predictive for a certain impaired hepatic function estimated by ICG clearance in severe CLD such as LC.博士（医学）・乙第1301号・平成24年7月26日Hepato Gastroenterology © 200