HARP : a shared repository project for university libraries in Hiroshima prefecture

DRFIC2008 Poster Session No.21DRFIC2008 ポスターセッション資料 21

HARP : a shared repository project for university libraries in Hiroshima prefecture

DRFIC2008 Poster Session Recap one-minute oral presentation No.21DRFIC2008 ポスターセッションまとめ 口頭プレゼンテーション資料 21

Development of singlet oxygen absorption capacity (SOAC) assay method. 4. Measurements of the SOAC values for vegetable and fruit extracts

<div><p>Measurements of the second-order rate constants and the singlet oxygen absorption capacity (SOAC) values for the reaction of singlet oxygen (¹O₂) with 23 kinds of food extracts were performed in ethanol/chloroform/D₂O (50:50:1, v/v/v) solution at 35 °C. It has been clarified that the SOAC method is useful to evaluate the ¹O₂-quenching activity (i.e. the SOAC value) of food extracts having two orders of magnitude different rate constants from 3.18 × 10⁴ L g⁻¹ s⁻¹ for tomato to 1.55 × 10² for green melon. Furthermore, comparison of the observed rate constants for the above food extracts with the calculated ones based on the concentrations of seven kinds of carotenoids included in the food extracts and the rate constants reported for each carotenoids was performed, in order to ascertain the validity of the SOAC assay method developed and to clarify the ratio of the contribution of principal carotenoids to the SOAC value.</p></div

A high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure measurement

We present the design and performance of a high-temperature in situ cell with a large solid angle for fluorescence X-ray absorption fine structure (XAFS) spectra. The cell has a large fluorescence XAFS window (116 mm(phi)) near the sample in the cell, realizing a large half-cone angle of 56 degrees. We use a small heater (25 x 35 mm(2)) to heat the sample locally to 873 K. We measured a Pt-SnO2 thin layer on a Si substrate at reaction conditions having a high activity. In situ measurement enables the analysis of the difference XAFS spectra between before and during the reaction to reveal the structure change during the operation. (C) 2015 AIP Publishing LLC

Development of Surface Fluorescence X‐Ray Absorption Fine Structure Spectroscopy Using a Laue‐Type Monochromator

Surface fluorescence X-ray absorption fine structure (XAFS) spectroscopy using a Laue-type monochromator has been developed to acquire structural information about metals with a very low concentrate on a flat highly oriented pyrolytic graphite (HOPG) surface in the presence of electrolytes. Generally, surface fluorescence XAFS spectroscopy is hindered by strong scattering from the bulk, which often chokes the pulse counting detector. In this work, we show that a bent crystal Laue analyzer (BCLA) can efficiently remove the scattered X-rays from the bulk even in the presence of solution. We applied the technique to submonolayer (similar to 10(14) atoms cm(-2)) Pt on HOPG and successfully obtained high signal/noise in situ XAFS data in combination with back-illuminated fluorescence XAFS (BI-FXAFS) spectroscopy. This technique allows in situ XAFS measurements of flat electrode surfaces to be performed in the presence of electrolytes

Learning by experience in 2011 : the natural and historical treasures of Miyajima (Itsukushima) Island.

広島県廿日市市宮島には厳島神社を代表とする文化遺産だけでなく,弥山原始林を代表とする貴重な自然や室浜砲台など日本の近代化の過程を象徴する遺産が多く存在する。また,広島大学には理学研究科附属宮島自然植物実験所をはじめとする宮島に関する多くの教育・研究資産が存在する。これまで,附属三原学校園と宮島自然植物実験所は共同で,これらのリソースを利用した野外教育実践を行ってきた。本研究では,本年度も継続して教育実践を行うとともに,その教育効果を明らかにすることを目的とした。また,実物に触れ,体験することで,地元社会の歴史や自然に対する理解を深めることができる。さらに,理科離れを防ぐとともに附属学校における教育効果を高めることもできる。テキストとして「宮島の植物と自然」を利用し,宮島で開催された野外自然実習へ希望者を募って参加させるとともに,室浜砲台などの歴史的遺産について現地を訪れて見学した。また,宮島の植物についてより理解を深めるため解説および野外での指導を行った。実施前後の生徒の感想文からキーワードを抽出し比較した。実習前後の宮島に対するイメージの変化を把握することで,教育効果を評価した

Development of a Singlet Oxygen Absorption Capacity (SOAC) Assay Method. Measurements of the SOAC Values for Carotenoids and α‑Tocopherol in an Aqueous Triton X‑100 Micellar Solution

Recently, a new assay method for the quantification of the singlet oxygen absorption capacity (SOAC) of antioxidants (AOs) and food extracts in homogeneous organic solvents was proposed. In this study, second-order rate constants (<i>k</i>_Q) for the reaction of singlet oxygen (¹O₂) with eight different carotenoids (Cars) and α-tocopherol (α-Toc) were measured in an aqueous Triton X-100 (5.0 wt %) micellar solution (pH 7.4, 35 °C), which was used as a simple model of biomembranes. The <i>k</i>_Q and relative SOAC values were measured using ultraviolet–visible (UV–vis) spectroscopy. The UV–vis absorption spectra of Cars and α-Toc were measured in both a micellar solution and chloroform, to investigate the effect of solvent on the <i>k</i>_Q and SOAC values. Furthermore, decay rates (<i>k</i>_d) of ¹O₂ were measured in 0.0, 1.0, 3.0, and 5.0 wt % micellar solutions (pH 7.4), using time-resolved near-infrared fluorescence spectroscopy, to determine the absolute <i>k</i>_Q values of the AOs. The results obtained demonstrate that the <i>k</i>_Q values of AOs in homogeneous and heterogeneous solutions vary notably depending on (i) the polarity [dielectric constant (ε)] of the reaction field between AOs and ¹O₂, (ii) the local concentration of AOs, and (iii) the mobility of AOs in solution. In addition, the <i>k</i>_Q and relative SOAC values obtained for the Cars in a heterogeneous micellar solution differ remarkably from those in homogeneous organic solvents. Measurements of <i>k</i>_Q and SOAC values in a micellar solution may be useful for evaluating the ¹O₂ quenching activity of AOs in biological systems