Institution
Osaka University
Education•Osaka, Japan•
About: Osaka University is a education organization based out in Osaka, Japan. It is known for research contribution in the topics: Laser & Catalysis. The organization has 83778 authors who have published 185669 publications receiving 5158122 citations. The organization is also known as: Ōsaka daigaku.
Topics: Laser, Catalysis, Population, Gene, Thin film
Papers published on a yearly basis
Papers
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TL;DR: The present Pd catalyst does not require additives to complete the catalytic cycle, and the diameters of the generated Pd nanoclusters can be controlled upon acting on the alcohol substrates used.
Abstract: Treatment of a stoichiometric hydroxyapatite (HAP), Ca10(PO4)6(OH)2, with PdCl2(PhCN)2 gives a new type of palladium-grafted hydroxyapatite. Analysis by means of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray (EDX), IR, and Pd K-edge X-ray absorption fine structure (XAFS) proves that a monomeric PdCl2 species is chemisorbed on the HAP surface, which is readily transformed into Pd nanoclusters with a narrow size distribution in the presence of alcohol. Nanoclustered Pd0 species can effectively promote the alcohol oxidation under an atmospheric O2 pressure, giving a remarkably high turnover number (TON) of up to 236,000 with an excellent turnover frequency (TOF) of approximately 9800 h(-1) for a 250-mmol-scale oxidation of 1-phenylethanol under solvent-free conditions. In addition to advantages such as a simple workup procedure and the ability to recycle the catalyst, the present Pd catalyst does not require additives to complete the catalytic cycle. The diameters of the generated Pd nanoclusters can be controlled upon acting on the alcohol substrates used. Oxidation of alcohols is proposed to occur primarily on low-coordination sites within a regular arrangement of the Pd nanocluster by performing calculations on the palladium crystallites.
863 citations
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TL;DR: This work combines production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression, allowing efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production.
Abstract: Modern high-power lasers can generate extreme states of matter that are relevant to astrophysics, equation-of-state studies and fusion energy research. Laser-driven implosions of spherical polymer shells have, for example, achieved an increase in density of 1,000 times relative to the solid state. These densities are large enough to enable controlled fusion, but to achieve energy gain a small volume of compressed fuel (known as the 'spark') must be heated to temperatures of about 108 K (corresponding to thermal energies in excess of 10 keV). In the conventional approach to controlled fusion, the spark is both produced and heated by accurately timed shock waves, but this process requires both precise implosion symmetry and a very large drive energy. In principle, these requirements can be significantly relaxed by performing the compression and fast heating separately; however, this 'fast ignitor' approach also suffers drawbacks, such as propagation losses and deflection of the ultra-intense laser pulse by the plasma surrounding the compressed fuel. Here we employ a new compression geometry that eliminates these problems; we combine production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression. Our approach therefore permits efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production.
861 citations
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TL;DR: The primary structure of a voltage-dependent cal-cium channel from rabbit brain has been deduced by cloning and sequencing the complementary DNA and it is suggested that it is expressed predominantly in cerebellar Purkinje cells and granule cells.
Abstract: The primary structure of a voltage-dependent cal-cium channel from rabbit brain has been deduced by cloning and sequencing the complementary DNA. Calcium channel activity expressed from the cDNA is dramatically increased by coexpression of the α2 and β subunits, known to be associated with the dihydropyridine receptor. This channel is a high voltage-activated calcium channel that is insensitive both to nifedipine and to ω-conotoxin. We suggest that it is expressed predominantly in cerebellar Purkinje cells and granule cells.
860 citations
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TL;DR: In this paper, DNA methylation and Piwi-interacting small RNA (piRNA) expression were analyzed in wild-type, MILI-null, and MIWI2-null male fetal germ cells.
Abstract: Silencing of transposable elements occurs during fetal gametogenesis in males via de novo DNA methylation of their regulatory regions. The loss of MILI (miwi-like) and MIWI2 (mouse piwi 2), two mouse homologs of Drosophila Piwi, activates retrotransposon gene expression by impairing DNA methylation in the regulatory regions of the retrotransposons. However, as it is unclear whether the defective DNA methylation in the mutants is due to the impairment of de novo DNA methylation, we analyze DNA methylation and Piwi-interacting small RNA (piRNA) expression in wild-type, MILI-null, and MIWI2-null male fetal germ cells. We reveal that defective DNA methylation of the regulatory regions of the Line-1 (long interspersed nuclear elements) and IAP (intracisternal A particle) retrotransposons in the MILI-null and MIWI2-null male germ cells takes place at the level of de novo methylation. Comprehensive analysis shows that the piRNAs of fetal germ cells are distinct from those previously identified in neonatal and adult germ cells. The expression of piRNAs is reduced under MILI- and MIWI2-null conditions in fetal germ cells, although the extent of the reduction differs significantly between the two mutants. Our data strongly suggest that MILI and MIWI2 play essential roles in establishing de novo DNA methylation of retrotransposons in fetal male germ cells.
859 citations
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TL;DR: Owing to the interfacial interaction between BP and CN, efficient charge transfer occurred, thereby enhancing the photocatalytic performance, and the present results show that BP/CN is a metal-free photocatalyst for artificial photosynthesis and renewable energy conversion.
Abstract: In the drive toward green and sustainable chemistry, exploring efficient and stable metal-free photocatalysts with broadband solar absorption from the UV to near-infrared region for the photoreduction of water to H2 remains a big challenge. To this end, a binary nanohybrid (BP/CN) of two-dimensional (2D) black phosphorus (BP) and graphitic carbon nitride (CN) was designed and used as a metal-free photocatalyst for the first time. During irradiation of BP/CN in water with >420 and >780 nm light, solid H2 gas was generated, respectively. Owing to the interfacial interaction between BP and CN, efficient charge transfer occurred, thereby enhancing the photocatalytic performance. The efficient charge-trapping and transfer processes were thoroughly investigated with time-resolved diffuse reflectance spectroscopic measurement. The present results show that BP/CN is a metal-free photocatalyst for artificial photosynthesis and renewable energy conversion.
857 citations
Authors
Showing all 84130 results
Name | H-index | Papers | Citations |
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Shizuo Akira | 261 | 1308 | 320561 |
Thomas C. Südhof | 191 | 653 | 118007 |
Tadamitsu Kishimoto | 181 | 1067 | 130860 |
Yusuke Nakamura | 179 | 2076 | 160313 |
H. S. Chen | 179 | 2401 | 178529 |
Hyun-Chul Kim | 176 | 4076 | 183227 |
Masayuki Yamamoto | 171 | 1576 | 123028 |
Kenji Kangawa | 153 | 1117 | 110059 |
Jongmin Lee | 150 | 2257 | 134772 |
Yoshio Bando | 147 | 1234 | 80883 |
Takeo Kanade | 147 | 799 | 103237 |
Olaf Reimer | 144 | 716 | 74359 |
Yuji Matsuzawa | 143 | 836 | 116711 |
Kim Nasmyth | 142 | 294 | 59231 |
Tasuku Honjo | 141 | 712 | 88428 |