Chemical Constituent of Acacia auriculiformis Wood Extractives and Their Antioxidant Activity

Acacia auriculiformis showed good potential to be developed as a raw material for bioactive compounds. The heartwood of A. auriculiformis is still rarely explored. The purpose of this study was to identify the bioactive components of the heartwood. Six compounds were identified from the heartwood through nuclear magnetic resonance and mass spectroscopy, namely the C-3,4',7,8 hydroxyl substituted flavonoids and chalcone. Two methylated teracacidins and chalcone-like teracacidin were identified for the first time in the A. auriculiformis heartwood, along with three known compounds. These compounds showed good radical scavenging and reduction activity, compared to crude extract and ascorbic acid, using three different antioxidant assays. The molecular structure-dependent activity was observed to affect the trend of the different antioxidant activities. This finding shows good potential for further development of plant parts of A. auriculiformis from Indonesia as new raw materials for medicines. Keywords: Acacia auriculiformis, antioxidant, chalcone, flavonoid, heartwoo

Congenital Web-like Tracheal Stenosis Cured Surgically in Adult

A 60-year-old, Japanese woman, with congenital web-like tracheal stenosis surgically treated. Successful relief from tracheal stenosis was obstained. Detection in adulthood and chance of the treatment for congenital tracheal stenosis is very rare. As far as this case is concerned, delay in detection and treatment is discussed of congenital tracheal stenosis

The ASTRO-H X-ray Observatory

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray

Hitomi (ASTRO-H) X-ray Astronomy Satellite

The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E  >  2  keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month

熱帯産薬用植物成分のメラニン生合成制御機構に関する研究

博士(農学)岐阜大学(Gifu University

Theoretical Study on the Mechanism of Hydrogen Evolution Reaction Catalyzed by Platinum Subnanoclusters

The smallest subnanocluster models of platinum colloid (Ptn) are supposed to diffuse in aqueous media in order to examine their behaviors when they are subjected to electrocatalytic hydrogen evolution reaction under the zero overpotential condition at pH 0. The DFT approach allows us to clarify the natures of individual proton transfer (PT) and electron transfer (ET) processes together with the importance of relying on concerted proton-electron transfer (CPET) pathways to promote the majority of H* adsorption processes by the Ptn subnanoclusters. Although the CPET processes are closely correlated with the Volmer steps (Pt + H+ + e− --> Pt-H*) described so far in electrochemistry, our study for the first time points out the essential capability of the Ptn clusters to promote the multiple PT steps without the need to transfer any electrons, revealing the fundamentally high basicity of the naked Ptn clusters (pKa = 27-28 for Pt4, Pt5, and Pt6). The discrete cluster models adopted herein avoid the structural constraints forced by the standard slab models and enable us to discuss the drastic alterations in the geometric and electronic structures of the intermediates given by the consecutive promotion of multiple CPET steps. The weakening in the Pt-H* bond strength with the increasing number of CPET steps is well rationalized by carefully examining the changes in the ν(Pt-H*) vibrational frequencies, the hydricity, and the H2 desorption energy. The behaviors are also correlated with the underpotential and overpotential deposited hydrogen atoms (HUPD and HOPD) discussed in the electrochemical studies for many years

高い触媒活性と耐久性を併せ持つ分子性触媒の開発を目指した白金錯体の水素生成触媒作用に関する研究

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