Determination of antioxidant activity of herbs by ESR

Water extracts of 32 herbs that are constituents of curry and curry powder were screened for superoxide anion radical (O2.-) scavenging activity. Among the screened samples, only clove, allspice, and basil were shown to decrease DMPO-O2.- adduct yields by more than 50% at 0.25 mg/mL as measured by an ESR spin trapping technique based on the HPX-XOD reaction. To study the mechanism of the O2.- scavenging activity, Km values were obtained from a Lineweaver-Burk plot for XOD in the presence of different concentrations of HPX, and the IC50 values at different DMPO concentrations were compared. Clove and basil directly eliminated O2.- like superoxide dismutase (SOD), whereas allspice reduced the amount of O2.- by inhibition of formation of O2.-.     

Growth of plate-type β-FeSi2 single crystals by optimization of composition ratio of source materials

The importance of the β-FeSi₂ bulk single crystals has increased not only to investigate the intrinsic properties of β-FeSi₂ but also to use it as substrate of β-FeSi₂ thin films for optical devices. Though single crystals of β-FeSi₂ are grown by chemical vapor transport (CVT) method, most of those crystals are needle-like and widths of those flat surfaces are 0.5 mm or less. In order to understand the mechanism of the growth process of β-FeSi₂ by the CVT method and to obtain the conditions for large size crystal growth, we have carried out in-situ observations of the crystal growth by using a transparent electric furnace. Based on the experimental data, we have proposed the most likely reaction process, FeI₂(g) + 2SiI₄(g)→FeSi₂(s) + 5I₂(g), and we found that the crystal growth progresses under the environment where the FeI₂ gas is insufficient compared with a suitable ratio of FeI₂/SiI₄. Then, to raise the partial pressure of FeI₂ gas, the composition ratio of Fe to Si for the source material was increased and we have obtained the plate-type β-FeSi₂ crystals that exceeded a few square millimeters in size.     

Improving cache attacks by considering cipher structure

A concrete attack using side channel information from cache memory behaviour was proposed for the first time at ISITA 2002. The attack uses the difference between execution times associated with S-box cache-hits and cache-misses to recover the intermediate key. Recently, a theoretical estimation of the number of messages needed for the attack was proposed and it was reported that the average method obtains key information with fewer messages than maximum threshold or intermediate threshold method. Taking the structure of cipher into account, this paper provided the cache attack in which the average method is embodied, and provides improved key estimation. This paper includes the study on the attack that exploits internal collision. Yukiyasu Tsunoo received his BE degree from Waseda University in 1982, MS degree from JAIST, Dr.Eng from Chuo University. He joined NEC Software Hokuriku, Ltd. in 1985. He is now a research fellow of NEC Internet Systems Research Laboratories. He is engaged in the designing of common key ciphers and the study of evaluation technique. Dr. Tsunoo is a member of the Expert Commission of Information Security Research, The Institute of Electronics, Information and Communication Engineers, the Information Processing Society of Japan, the Japan Society for Security Management and the Atomic Energy Society of Japan. Etsuko Tsujihara received her BS degree from Aoyama Gakuin University in 1983. She joined NEC in 1983. She developed the VLSI automatic layout system. She joined NEC Software Hokuriku Ltd. in 1986 and Y.D.K. Co. Ltd. in 2004. She is engaged in the designing of common key ciphers and the study of evaluation technique. Maki Shigeri received her BE degree from University of Tsukuba in 1992. She joined NEC Software Hokuriku Ltd. in 1992. She is engaged in the designing of common key ciphers and the study of evaluation technique. Hiroyasu Kubo received his BE degree from Kanazawa Institute of Technology in 1990. He joined NEC Software Hokuriku Ltd. in 1990. He is engaged in the designing of common key ciphers and the study of evaluation technique. Kazuhiko Minematsu received his BS degree from Waseda University in 1996, MS degree in 1998 and joined NEC in 1998. He is engaged in the designing of common key ciphers and research on block cipher modes of operations. He is a member of the Information Processing Society of Japan, the Society of Information Theory and Its Applications.     

A parameter tuning method for an elevator group control system using a genetic algorithm

This paper describes a new parameter tuning method for an elevator group control system. In such a system, tuning parameters describing elevator use and the building environment are important. The new tuning method uses improved genetic algorithms to follow environment changes and to give robustness. Keeping diversity is important in following environment changes. The paper also describes the addition of the random chromosome method and addition of other estimation methods to maintain diversity. Their effects are shown by simulations. © 1998 Scripta Technica, Electr Eng Jpn, 124(1), 55–64, 1998     

Evolution of the ITER program and prospect for the next-step fusion DEMO reactors: status of the fusion energy R&D as ultimate source of energy

An international joint project of fusion experimental reactor, the ITER (International Thermonuclear Experimental Reactor), is reviewed in view of long-range fusion energy research and development (R&D). Its purpose, goal, evolution, and the present construction status are briefly reviewed. While the ITER is a core machine in the present stage, generation of electricity is a role of the next-step fusion demonstration power plant “DEMO.” The status of designs and technology R&D for DEMO are also reviewed.     

Efforts towards improvement of systems codes for the Broader Approach DEMO design

We report our recent efforts towards improvement of systems codes for the Broader Approach DEMO design, i.e. benchmarking the two systems codes the Japan and EU home teams are developing independently. The main result is that most of calculated outputs from the two codes are in good agreement. The main disagreement in the current benchmarking is the calculated radiation power losses from the plasma. Close examination shows that this is due to differences in the impurity radiation and transport models. Some issues for development/improvement of systems codes relevant to DEMO plasma physics are discussed.