50 research outputs found

    Threshold of photoelectron emission from CNx films deposited at room temperature and at 500 °C

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    The threshold of photoelectron emission was measured for amorphous CNx films deposited at room temperature (RT) and at 500 °C. The x values of the films deposited at RT and at 500 °C by magnetron sputtering of a graphite target in a mixed N2/Ar gas were 0.6 and 0.3, respectively. Ratios of the sp2- to sp3-hybridized components of both C and N for the film deposited at 500 °C were larger by 4 times than those for the film deposited at RT. The onsets of the electron emission by photon irradiation were 5.0 and 4.7 eV for the films deposited at RT and at 500 °C, respectively

    Establishment of sandwich ELISA for soluble alpha-Klotho measurement: Age-dependent change of soluble alpha-Klotho levels in healthy subjects

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    Background α-Klotho (αKl) regulates mineral metabolism such as calcium ion (Ca2+) and inorganic phosphate (Pi) in circulation. Defects in mice result in clinical features resembling disorders found in human aging. Although the importance of transmembrane-type αKl has been demonstrated, less is known regarding the physiological importance of soluble-type αKl (sαKl) in circulation. Objectives The aims of this study were: (1) to establish a sandwich ELISA system enabling detection of circulating serum sαKl, and (2) to determine reference values for sαKl serum levels and relationship to indices of renal function, mineral metabolism, age and sex in healthy subjects. Results We successively developed an ELISA to measure serum sαKl in healthy volunteers (n = 142, males 66) of ages (61.1 ± 18.5 year). The levels (mean ± SD) in these healthy control adults were as follows: total calcium (Ca; 9.46 ± 0.41 mg/dL), Pi (3.63 ± 0.51 mg/dL), blood urea nitrogen (BUN; 15.7 ± 4.3 mg/dL), creatinine (Cre; 0.69 ± 0.14 mg/dL), 1,25 dihydroxyvitamin D (1,25(OH)2D; 54.8 ± 17.7 pg/mL), intact parathyroid hormone (iPTH; 49.2 ± 20.6 pg/mL), calcitonin (26.0 ± 12.3 pg/mL) and intact fibroblast growth factor (FGF23; 43.8 ± 17.6 pg/mL). Serum levels of sαKl ranged from 239 to 1266 pg/mL (mean ± SD; 562 ± 146 pg/mL) in normal adults. Although sαKl levels were not modified by gender or indices of mineral metabolism, sαKl levels were inversely related to Cre and age. However, sαKl levels in normal children (n = 39, males 23, mean ± SD; 7.1 ± 4.8 years) were significantly higher (mean ± SD; 952 ± 282 pg/mL) than those in adults (mean ± SD; 562 ± 146, P < 0.001). A multivariate linear regression analysis including children and adults in this study demonstrated that sαKl correlated negatively with age and Ca, and positively with Pi. Finally, we measured a serum sαKl from a patient with severe tumoral calcinosis derived from a homozygous missense mutation of α-klotho gene. In this patient, sαKl level was notably lower than those of age-matched controls. Conclusion We established a detection system to measure human serum sαKl for the first time. Age, Ca and Pi seem to influence serum sαKl levels in a normal population. This detection system should be an excellent tool for investigating sαKl functions in mineral metabolism

    Fabrication of Nanosized Structures on Nafion Membranes by Thermal Nanoimprinting

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    Low-Temperature Synthesis of Cu-Doped Anatase TiO<sub>2</sub> Nanostructures via Liquid Phase Deposition Method for Enhanced Photocatalysis

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    Titanium dioxide (TiO2) photocatalysis can harness the energy from sunlight, providing a solution to many green- and energy-related problems. In this study, we aimed to produce Cu doped TiO2 (Cu-TiO2) structures at a low temperature (~70 °C) under atmospheric pressure based on liquid phase deposition. The products prepared with Cu nitrate exhibited anatase-phase TiO2 with the presence of Cu, and the particles showed a waxberry-like structure. Changing the Cu nitrate concentration allowed control of the atomic concentration; we confirmed ~1.3 atm.% of Cu ions in the product when we applied 10 mM in the precursor solution. By doping Cu, the light absorption edge shifted to 440 nm (~2.9 eV), and we proved the photocatalytic reaction through action spectral measurement. We observed the decomposition of acetaldehyde into CO2 on Cu-TiO2 photocatalysts, which produced optimized improvements in photocatalytic activity at Cu dopant levels between 0.2 and 0.4 atm.%. This study demonstrates that the liquid phase deposition technique can be used for doping metallic ions into TiO2, which shows promise for preparing novel and unique nanomaterials as visible light photocatalysts

    低融点燃料を用いたハイブリッドロケットのスケール効果に関する理論的研究

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