144 research outputs found

    Accessing surface Brillouin zone and band structure of picene single crystals

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    We have experimentally revealed the band structure and the surface Brillouin zone of insulating picene single crystals (SCs), the mother organic system for a recently discovered aromatic superconductor, with ultraviolet photoelectron spectroscopy (UPS) and low-energy electron diffraction with laser for photoconduction. A hole effective mass of 2.24 m_0 and the hole mobility mu_h >= 9.0 cm^2/Vs (298 K) were deduced in Gamma-Y direction. We have further shown that some picene SCs did not show charging during UPS even without the laser, which indicates that pristine UPS works for high-quality organic SCs.Comment: 5 pages, 4 figures, Phys. Rev. Lett. 108, 226401 (2012

    Mail-in data collection at SPring-8 protein crystallography beamlines

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    A mail-in data collection system at SPring-8, which is a web application with automated beamline operation, has been developed

    Identification of semen from criminal materials by means of paper chromatography--a forensic-medical study

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    In the present experiments attempts were made to identify semen from various specimens such as the semen itself, spots of semen on clothes, putrefied semen or semen contaminated with blood, menstrual blood, vaginal fluid, according to the techniques of LEVONEN. As the result it has been clarified that in every instance it is possible to isolate and detect the spots of choline by spraying Dragehdorff's reagent.</p

    Photoelectron spectroscopy on the charge reorganization energy and small polaron binding energy of molecular film

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    AbstractUnderstanding of electron-phonon coupling as well as intermolecular interaction is required to discuss the mobility of charge carrier in functional molecular solids. This article summarizes recent progress in direct measurements of valence hole-vibration coupling in ultrathin films of organic semiconductors by using ultraviolet photoelectron spectroscopy (UPS). The experimental study of hole-vibration coupling of the highest occupied molecular orbital (HOMO) state in ordered monolayer film by UPS is essential to comprehend hole-hopping transport and small-polaron related transport in organic semiconductors. Only careful measurements can attain the high-resolution spectra and provide key parameters in hole-transport dynamics, namely the charge reorganization energy and small polaron binding energy. Analyses methods of the UPS HOMO fine feature and resulting charge reorganization energy and small polaron binding energy are described for pentacene and perfluoropentacene films. Difference between thin-film and gas-phase results is discussed by using newly measured high-quality gas-phase spectra of pentacene. Methodology for achieving high-resolution UPS measurements for molecular films is also described

    Implication of Plaque Color Classification for Assessing Plaque Vulnerability A Coronary Angioscopy and Optical Coherence Tomography Investigation

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    ObjectivesThe purpose of this study was to assess the relationship between plaque color evaluated by coronary angioscopy and fibrous cap thickness estimated by optical coherence tomography (OCT) in vivo.BackgroundYellow color intensity of coronary plaque evaluated by coronary angioscopy might be associated with plaque vulnerability.MethodsSeventy-seven coronary artery plaques in patients with acute coronary syndrome were observed by angioscopy and OCT. Plaque color was graded as white, light yellow, yellow, or intensive yellow.ResultsThere were significant differences among the groups classified by plaque color with respect to the fibrous cap thickness estimated by OCT: 389 ± 74 μm in white plaques, 228 ± 51 μm in light yellow plaques, 115 ± 28 μm in yellow plaques, and 59 ± 14 μm in intensive yellow plaques (p &lt; 0.0001). In Spearman rank-order correlation analysis, there was a significant negative correlation between yellow color intensity and fibrous cap thickness (p &lt; 0.0001). Furthermore, 80% of intensive yellow plaques were thin cap fibroatheroma with a cap thickness of ≤65 μm.ConclusionsThe plaque color in coronary angioscopy was determined by the fibrous cap thickness, which was assessed by OCT. Although coronary angioscopy remains a specialized research tool, it might allow us to evaluate plaque vulnerability

    Abrupt rotation of the rashba spin to the direction perpendicular to the surface

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    金沢大学理工研究域数物科学系The polarization vector of the Rashba spin, which must be parallel to the two-dimensional (2D) plane in an ideal system, is found to change abruptly and definitely to the direction perpendicular to the surface at the K̄ point of the Brillouin zone of a real hexagonal system, the Tl/Si(111)-(1×1) surface. This finding obtained experimentally by angle-resolved and spin-resolved photoemission measurements is fully confirmed by a first-principles theoretical calculation. We found that the abrupt rotation of the Rashba spin is simply understood by the 2D symmetry of the hexagonal structure. © 2009 The American Physical Society

    The Iron Discrepancy in Elliptical Galaxies after ASCA

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    We present estimates for the iron content of the stellar and diffused components of elliptical galaxies, as derived respectively from integrated optical spectra and from ASCA X-ray observations. A macroscopic discrepancy emerges between the expected iron abundances in the hot interstellar medium (ISM) and what is indicated by the X-ray observations, especially when allowance is made for the current iron enrichment by Type Ia supernovae. This strong discrepancy, that in some extreme instances may be as large as a factor of 20\sim 20, calls into question our current understanding of supernova enrichment and chemical evolution of galaxies. We discuss several astrophysical implications of the inferred low iron abundances in the ISM, including the chemical evolution of galaxies and cluster of galaxies, the evolution of gas flows in ellipticals, and the heating of the intracluster medium. Some of the consequences appear hard to accept, and in the attempt to avoid some of these difficulties we explore ways of hiding or diluting iron in the ISM of ellipticals. None of these possibilities appears astrophysically plausible, and we alternatively rise the question of the reliability of iron-L line diagonostic tools. Various thin plasma emission models are shown to give iron abundances that may differ significantly, especially at low temperatures (kT \lsim 1 keV). From a collection of ASCA and other X-ray observatory data, it is shown that current thin plasma codes tend to give very low iron abundances when the temperature of the objects is below 1\sim 1 keV. We conclude that -- besides rethinking the chemical evolution of galaxies -- one should also consider the possibility that existing thin plasma models may incorporate inaccurate atomic physics for the ions responsible for the iron-L complex.Comment: 39 pages, TeX file, 5 figures, Accepted for publication in the Ap

    p62/SQSTM1-droplet serves as a platform for autophagosome formation and anti-oxidative stress response

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    Autophagy contributes to the selective degradation of liquid droplets, including the P-Granule, Ape1-complex and p62/SQSTM1-body, although the molecular mechanisms and physiological relevance of selective degradation remain unclear. In this report, we describe the properties of endogenous p62-bodies, the effect of autophagosome biogenesis on these bodies, and the in vivo significance of their turnover. p62-bodies are low-liquidity gels containing ubiquitin and core autophagy-related proteins. Multiple autophagosomes form on the p62-gels, and the interaction of autophagosome-localizing Atg8-proteins with p62 directs autophagosome formation toward the p62-gel. Keap1 also reversibly translocates to the p62-gels in a p62-binding dependent fashion to activate the transcription factor Nrf2. Mice deficient for Atg8-interaction-dependent selective autophagy show that impaired turnover of p62-gels leads to Nrf2 hyperactivation in vivo. These results indicate that p62-gels are not simple substrates for autophagy but serve as platforms for both autophagosome formation and anti-oxidative stress. Liquid-liquid phase separation of p62/SQSTM1 has been previously described, although the significance in vivo remains unclear. Here the authors show p62 droplets contain ubiquitin, autophagy-related proteins and Keap1 to serve as platform of not only autophagosome formation but also Nrf2 activation.Peer reviewe
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