円偏光アンジュレーターと外部磁場によるアミノ酸の光不斉化反応の研究

研究期間:平成13-14年度 ; 研究種別:基盤研究C2 ; 課題番号: 13640593発表論文などあり

HiSOR multimode undulator as a circularly polarized light source

A linear/helical multimode undulator, which is installed at storage ring in Hiroshima Synchrotron Radiation Center, is initially designed for the utilizing of circularly polarized light from its fundamental harmonic in the spectral range of 4 - 40 eV. Operating of the undulator in elliptical configuration may considerably extend this spectral region. This paper presents a study for the optimisation of operating parameters of a linear/helical multimode undulator with the aim to maximize the circularly polarized high-energy photons output. The comparison with the correspondent characteristics of synchrotron radiation from bending magnet is performed. The results presented here were obtained for the general case that provides a means of applying derived expressions for any kind of elliptical wiggler as well as bending magnet

Sentimientos de gestantes VIH-positivas sobre aspectos relacionados con la transmisión vertical

En sus orígenes, el Virus de la Inmunodeficiencia Humana (VIH) fue una epidemia vinculada principalmente a hombres homosexuales y personas drogadictas. Sin embargo, en los últimos años se ha producido un incremento del número de casos por transmisión heterosexual, donde la infección de la mujer es de 2 a 10 veces más probable. Este cambio epidemiológico ha provocado un aumento de casos entre la población femenina en todo el mundo, dando lugar a lo que se conoce como la feminización de la epidemia

High-Resolution X-ray Spectroscopy of the Interstellar Medium

The interstellar medium (ISM) has a multiphase structure characterized by gas, dust and molecules. The gas can be found in different charge states: neutral, low-ionized (warm) and high-ionized (hot). It is possible to probe the multiphase ISM through the observation of its absorption lines and edges in the X-ray spectra of background sources. We present a high-quality RGS spectrum of the low-mass X-ray binary GS 1826-238 with an unprecedent detailed treatment of the absorption features due to the dust and both the neutral and ionized gas of the ISM. We constrain the column density ratios within the different phases of the ISM and measure the abundances of elements such as O, Ne, Fe and Mg. We found significant deviations from the proto-Solar abundances: oxygen is over-abundant by a factor 1.23 +/- 0.05, neon 1.75 +/- 0.11, iron 1.37 +/- 0.17 and magnesium 2.45 +/- 0.35. The abundances are consistent with the measured metallicity gradient in our Galaxy: the ISM appears to be metal-rich in the inner regions. The spectrum also shows the presence of warm/hot ionized gas. The gas column has a total ionization degree less than 10%. We also show that dust plays an important role as expected from the position of GS 1826-238: most iron appears to be bound in dust grains, while 10-40% of oxygen consists of a mixture of dust and molecules

Observation of circularly polarized radiation from multimode undulator at HiSOR

The linear / helical multimode undulator that is able to produce polarized radiation of any ellipticity operates successfully in Hiroshima Synchrotron Radiation Center. Polarization measurements have been performed for helical mode of undulator using IR-UV polarimeter at the beamline BL9 of the 700 MeV storage ring (HiSOR). High degree of circular polarization has been obtained. The comparison between achieved performance and numerical simulation was made. The main reason of slight distinction between them was found to be in the influence of non-undulator radiation

Preventive effect of statin pretreatment on contrast-induced acute kidney injury in patients undergoing coronary angioplasty: Propensity score analysis from a multicenter registry

BackgroundThe prophylactic benefit of statins in reducing the incidence of contrast-induced acute kidney injury (CI-AKI) has been investigated in several studies with conflicting results. We sought to investigate whether statin pretreatment prevents CI-AKI in coronary artery disease (CAD) patients undergoing percutaneous coronary intervention (PCI).MethodsA total of 2198 CAD patients who underwent PCI, except for those undergoing dialysis or who died within 7 days after angioplasty, were analyzed from the ICAS (Ibaraki Cardiovascular Assessment Study) multicenter registry. Analyzed subjects were divided into 2 groups according to statin pretreatment: statin pretreatment (n = 839) and non-statin pretreatment (n = 1359). Selection bias of statin pretreatment was adjusted by propensity score-matching method: pretreatment statin (n = 565) and non-statin pretreatment (n = 565). CI-AKI was defined as an increase in serum creatinine of ≥ 25% or 0.5 mg/dl from baseline within 1 week of contrast medium exposure.ResultsA total of 192 (8.7%) patients developed CI-AKI. No significant differences were observed in baseline patient characteristics between the statin and non-statin pretreatment groups after propensity score matching. In the propensity score-matched groups, the incidence of CI-AKI was significantly lower in patients with statin pretreatment than in those without statin pretreatment (3.5% vs.10.6%, odds ratio [OR]: 0.31, 95% confidence interval [CI]: 0.18–0.52, P < 0.001). Multivariate logistic regression analysis showed that statin pretreatment remained an independent negative predictor of CI-AKI (OR: 0.31, 95% CI: 0.18–0.53, P < 0.001) among propensity score-matched subjects.ConclusionsStatin pretreatment was associated with a significant decrease in the risk of CI-AKI in CAD patients undergoing PCI in the ICAS Registry

Molecular deformation in the O 1s[-1] 2πu excited states of CO2 probed by the triple-differential measurement of fragment ions

Measurement of mass-, energy-, and angle-resolved fragment ions reveals that the β value for C+ with kinetic energy ≥~3 eV is ∼0.9 in the region of the O 1s→2πu excitation and that the β value for O+ with kinetic energy ≥~4 eV varies from -0.23 to -0.57 across the O 1s→2πu resonance. These findings postulate that the CO2 molecule excited to the lower branch of the vibronically split O 1s[-1]2πu excited states deforms into a bent geometry while the molecule excited to the higher branch remains in a linear geometry