29 research outputs found

    Josephson junction in cobalt-doped BaFe2As2 epitaxial thin films on (La, Sr)(Al, Ta)O3 bicrystal substrates

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    Josephson junctions were fabricated in epitaxial films of cobalt-doped BaFe2As2 on [001]-tilt (La,Sr)(Al,Ta)O3 bicrystal substrates. 10m-wide microbridges spanning a 30-degrees-tilted bicrystal grain boundary (BGB bridge) exhibited resistively-shunted-junction (RSJ)-like current-voltage characteristics up to 17 K, and the critical current was suppressed remarkably by a magnetic field. Microbridges without a BGB did not show the RSJ-like behavior, and their critical current densities were 20 times larger than those of BGB bridges, confirming BGB bridges display a Josephson effect originating from weakly-linked BGB

    Biaxially textured cobalt-doped BaFe2As2 films with high critical current density over 1 MA/cm2 on MgO-buffered metal-tape flexible substrates

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    High critical current densities (Jc) > 1 MA/cm2 were realized in cobalt-doped BaFe2As2 (BaFe2As2:Co) films on flexible metal substrates with biaxially-textured MgO base-layers fabricated by an ion-beam assisted deposition technique. The BaFe2As2:Co films showed small in-plane crystalline misorientations (delta fai BaFe2As2:Co) of ~3o regardless of doubly larger misorientaions of the MgO base-layers (delta fai MgO = 7.3o), and exhibited high self-field Jc up to 3.5 MA/cm2 at 2 K. These values are comparable to that on MgO single crystals and the highest Jc among iron pnictide superconducting tapes and wires ever reported. High in-field Jc suggests the existence of c-axis correlated vortex pinning centers.Comment: Published in Appl. Phys. Let

    Increased urine level of amino-terminal peptide derivatives of type III procollagen in patients with liver diseases.

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    The amino-terminal peptides of type III procollagen (PIIIP) in the urine of 40 patients with various liver diseases were determined with a commercial radioimmunoassay kit. The level of urinary PIIIP (uPIIIP) was correlated well with serum PIIIP (sPIIIP) in 9 patients, the coefficient of correlation being r = 0.836 (p less than 0.01) and the regression line being y = 1.42x + 24. Urinary PIIIP consisted of at least 4 different molecular species with molecular weights of 49 k, 18 k, 10 k and 4.6 k as estimated by column chromatography on Sephadex G-100. Furthermore. uPIIIP was found to be significantly elevated in acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma and other liver diseases, in which the elevation of sPIIIP has been reported by others. The mean values +/- standard deviations of uPIIIP were 44.0 +/- 32.0, 60.4 +/- 32.0, 62.0 +/- 46.5, 53.0 +/- 27.1 and 48.1 +/- 22.8 ng/ml for the respective liver diseases, and 13.2 +/- 4.5 for the non-hepatic disease group

    DC superconducting quantum interference devices fabricated using bicrystal grain boundary junctions in Co-doped BaFe2As2 epitaxial films

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    DC superconducting quantum interference devices (dc-SQUIDs) were fabricated in Co-doped BaFe2As2 epitaxial films on (La, Sr)(Al, Ta)O3 bicrystal substrates with 30deg misorientation angles. The 18 x 8 micro-meter^2 SQUID loop with an estimated inductance of 13 pH contained two 3 micro-meter wide grain boundary junctions. The voltage-flux characteristics clearly exhibited periodic modulations with deltaV = 1.4 micro-volt at 14 K, while the intrinsic flux noise of dc-SQUIDs was 7.8 x 10^-5 fai0/Hz^1/2 above 20 Hz. The rather high flux noise is mainly attributed to the small voltage modulation depth which results from the superconductor-normal metal-superconductor junction nature of the bicrystal grain boundary

    Percutaneous Transluminal Angioscopy During Coronary Intervention

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    To investigate the feasibility of angioscopic-guided percutaneous transluminal coronary angioplasty and to elucidate the mechanism of efficacy of coronary stenting for acute myocardial infarction, we performed coronary angioscopy in 102 patients with stable angina or acute myocardial infarction. Thrombi and intimal flaps were observed in most patients after coronary angioplasty. Large intimal splits were seen in one third of patients. Stents were inserted in 10 patients who were revealed to have a large flap or protruding split to the inner lumen. Thrombolytic agents were administered in 2 patients with large thrombi. Additional treatments were required in 32% of patients. No acute myocardial infarction or unstable angina occurred in patients during hospitalization. Thus, angioscopy of the coronary lumen enables clinicians to determine the most appropriate and least risky coronary intervention strategy. In patients with acute myocardial infarction, angioscopy revealed occlusive or protruding thrombi in 34 of 35 patients. The protruding thrombi disappeared after stenting. The frequency of large intimal flaps increased after predilatation with balloon, but these disappeared after stenting. The present angioscopic study demonstrates that the coronary stent compresses the occlusive or protruding thrombi and covers the ruptured thrombogenic plaque Consequently, smooth-surfaced and wide vessel lumen are obtained

    Spectral evolution of GRB 060904A observed with Swift and Suzaku -- Possibility of Inefficient Electron Acceleration

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    We observed an X-ray afterglow of GRB 060904A with the Swift and Suzaku satellites. We found rapid spectral softening during both the prompt tail phase and the decline phase of an X-ray flare in the BAT and XRT data. The observed spectra were fit by power-law photon indices which rapidly changed from Γ=1.510.03+0.04\Gamma = 1.51^{+0.04}_{-0.03} to Γ=5.300.59+0.69\Gamma = 5.30^{+0.69}_{-0.59} within a few hundred seconds in the prompt tail. This is one of the steepest X-ray spectra ever observed, making it quite difficult to explain by simple electron acceleration and synchrotron radiation. Then, we applied an alternative spectral fitting using a broken power-law with exponential cutoff (BPEC) model. It is valid to consider the situation that the cutoff energy is equivalent to the synchrotron frequency of the maximum energy electrons in their energy distribution. Since the spectral cutoff appears in the soft X-ray band, we conclude the electron acceleration has been inefficient in the internal shocks of GRB 060904A. These cutoff spectra suddenly disappeared at the transition time from the prompt tail phase to the shallow decay one. After that, typical afterglow spectra with the photon indices of 2.0 are continuously and preciously monitored by both XRT and Suzaku/XIS up to 1 day since the burst trigger time. We could successfully trace the temporal history of two characteristic break energies (peak energy and cutoff energy) and they show the time dependence of t3t4\propto t^{-3} \sim t^{-4} while the following afterglow spectra are quite stable. This fact indicates that the emitting material of prompt tail is due to completely different dynamics from the shallow decay component. Therefore we conclude the emission sites of two distinct phenomena obviously differ from each other.Comment: 19 pages, 9 figures, accepted for publication in PASJ (Suzaku 2nd Special Issue

    The presence of vermipodia-like processes on the free surfaces of multicellular spheroids composed of adult rat hepatocytes in the primary culture

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    The presence and function of vermipodia-like processes of hepatocytes-multicellular spheroids formed in primary culture was described. Cine microscopy and scanning electron microscopy revealed that about 1-5% hepatocytes in single cell after culture initiation already posessed the processes. The processes disappeared when the hepatocytes attached and spread, and than appeared again on the surface of multicellular spheroides. The processes were moving by extending, shrinking and twisting, and sometimes extended 50 um. Five to ten percent of spheroids had 1-5 processes. Occasional collision of two spheroids resulted in the fusion of spheroids after their processes intertwined, attached to the partner spheroid and shrunk. Electron microscopy revealed that the processes were larger in size than the numerous microvilli co-present on the free surface of spheroids and their cytoplasm had scarece orgalella. The morphological characterisitcs of the processes most resembled those of vermipodia reported in histiocytic leukemia cells
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