148 research outputs found

    CALCULATION OF THE JOSEPHSON CURRENT IN P-WAVE AND S-WAVE SUPERCONDUCTING HETERO-JUNCTIONS BY BOGOLIUBOV TRANSFORMATION

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    Superconducting hetero-junction made of the p-wave superconductor and the normal s-wave superconductor has been considered. Bogoliubov transformation in the p-wave superconductor has been obtained by diagonalizing the superconducting Hamiltonian. Moreover, the value of the Josephson current that flows in the hetero-junctions of p-wave/s-wave superconductors has been calculated by this Bogoliubov transformation, and proved to be zero in the first order perturbation

    CHARACTERISTICS OF Y-BA-CU-O/NB AND BI-SR-CA-CU-O/NB TUNNEL-TYPE JOSEPHSON-JUNCTIONS

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    We have fabricated Y-Ba-Cu-O/Nb and Bi-Sr-Ca-Cu-O/Nb tunnel-type Junctions and observed the DC and AC Josephson effects. Gold thin films were deposited for an inter-layer to protect the reaction between the base electrode and the tunnel oxide before the tunnel barrier formation. In Y-Ba-Cu-O/Au/MgOx/Nb junctions, superconducting current, hysteresis of current-voltage characteristics and the rf-induced voltage steps at the voltage as high as 0.13 mV in the current-voltage characteristics were observed. Moreover, the superconducting current has been modulated by the magnetic field. In Bi-Sr-Ca-Cu-O/Au/MgO(x)/Nb junctions, superconducting current and the rf-induced voltage steps at the voltage as high as 0.15 mV were also observed

    EFFECTS OF ALUMINUM OVER-LAYER THICKNESS ON CHARACTERISTICS OF NIOBIUM TUNNEL-JUNCTIONS FABRICATED BY DC MAGNETRON SPUTTERING

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    We have fabricated Nb/AlOX/Nb Josephson tunnel junctions using a sputtering apparatus with a load-lock system. The junctions that had 50 mu m x 50 mu m area showed a V-m value (the product of the critical current and the subgap resistance at 2 mV) as high as 50 mV at a current density of 160 A/cm(2). Moreover, junctions having different thicknesses of the Al over-layer were concurrently fabricated on one wafer to study the dependence of the current-voltage characteristics on this Al over-layer. The I-V characteristics were also calculated by McMillan\u27s tunneling model and were compared with the measured I-V characteristics

    A Proposal for Practical Diagnosis of Renal Hypouricemia : Evidenced from Genetic Studies of Nonfunctional Variants of URAT1/SLC22A12 among 30,685 Japanese Individuals

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    Background: Renal hypouricemia (RHUC) is characterized by a low serum uric acid (SUA) level and high fractional excretion of uric acid (FEUA). Further studies on FEUA in hypouricemic individuals are needed for a more accurate diagnosis of RHUC. Methods: In 30,685 Japanese health-examination participants, we genotyped the two most common nonfunctional variants of URAT1 (NFV-URAT1), W258X (rs121907892) and R90H (rs121907896), in 1040 hypouricemic individuals (SUA ≤ 3.0 mg/dL) and 2240 individuals with FEUA data. The effects of NFV-URAT1 on FEUA and SUA were also investigated using linear and multiple regression analyses. Results: Frequency of hypouricemic individuals (SUA ≤ 3.0 mg/dL) was 0.97% (male) and 6.94% (female) among 30,685 participants. High frequencies of those having at least one allele of NFV-URAT1 were observed in 1040 hypouricemic individuals. Furthermore, NFV-URAT1 significantly increased FEUA and decreased SUA, enabling FEUA and SUA levels to be estimated. Conversely, FEUA and SUA data of hypouricemic individuals are revealed to be useful to predict the number of NFV-URAT1. Conclusions: Our findings reveal that specific patterns of FEUA and SUA data assist with predicting the number of nonfunctional variants of causative genes for RHUC, and can also be useful for practical diagnosis of RHUC even before genetic tests

    Diverse Bone Morphogenetic Protein Expression Profiles and Smad Pathway Activation in Different Phenotypes of Experimental Canine Mammary Tumors

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    BACKGROUND:BMPs are currently receiving attention for their role in tumorigenesis and tumor progression. Currently, most BMP expression studies are performed on carcinomas, and not much is known about the situation in sarcomas. METHODOLOGY/PRINCIPAL FINDINGS:We have investigated the BMP expression profiles and Smad activation in clones from different spontaneous canine mammary tumors. Spindle cell tumor and osteosarcoma clones expressed high levels of BMPs, in particular BMP-2, -4 and -6. Clones from a scirrhous carcinoma expressed much lower BMP levels. The various clones formed different tumor types in nude mice but only clones that expressed high levels of BMP-6 gave bone formation. Phosphorylated Smad-1/5, located in the nucleus, was detected in tumors derived from clones expressing high levels of BMPs, indicating an active BMP signaling pathway and BMP-2 stimulation of mammary tumor cell clones in vitro resulted in activation of the Smad-1/5 pathway. In contrast BMP-2 stimulation did not induce phosphorylation of the non-Smad pathway p38 MAPK. Interestingly, an increased level of the BMP-antagonist chordin-like 1 was detected after BMP stimulation of non-bone forming clones. CONCLUSIONS/SIGNIFICANCE:We conclude that the specific BMP expression repertoire differs substantially between different types of mammary tumors and that BMP-6 expression most probably has a biological role in bone formation of canine mammary tumors

    Genome-wide association study revealed novel loci which aggravate asymptomatic hyperuricaemia into gout

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    Objective The first ever genome-wide association study (GWAS) of clinically defined gout cases and asymptomatic hyperuricaemia (AHUA) controls was performed to identify novel gout loci that aggravate AHUA into gout. Methods We carried out a GWAS of 945 clinically defined gout cases and 1003 AHUA controls followed by 2 replication studies. In total, 2860 gout cases and 3149 AHUA controls (all Japanese men) were analysed. We also compared the ORs for each locus in the present GWAS (gout vs AHUA) with those in the previous GWAS (gout vs normouricaemia). Results This new approach enabled us to identify two novel gout loci (rs7927466 of CNTN5 and rs9952962 of MIR302F) and one suggestive locus (rs12980365 of ZNF724) at the genome-wide significance level (p<5.0×10– 8). The present study also identified the loci of ABCG2, ALDH2 and SLC2A9. One of them, rs671 of ALDH2, was identified as a gout locus by GWAS for the first time. Comparing ORs for each locus in the present versus the previous GWAS revealed three ‘gout vs AHUA GWAS’-specific loci (CNTN5, MIR302F and ZNF724) to be clearly associated with mechanisms of gout development which distinctly differ from the known gout risk loci that basically elevate serum uric acid level. Conclusions This meta-analysis is the first to reveal the loci associated with crystal-induced inflammation, the last step in gout development that aggravates AHUA into gout. Our findings should help to elucidate the molecular mechanisms of gout development and assist the prevention of gout attacks in high-risk AHUA individuals
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