[110]-surface strained-SOI CMOS devices

We have newly developed [110]-surface strained-silicon-on-insulator (SOI) n- and p-MOSFETs on [110]-surface relaxed-SiGe-on-insulator substrates with the Ge content of 25%, fabricated by applying the Ge condensation technique to SiGe layers grown on [110]-surface SOI wafers. We have demonstrated that the electron and the hole mobility enhancement of [110]-surface strained-SOI devices amounts to 23% and 50%, respectively, against the mobilities of [110]-surface unstrained MOSFETs. As a result, the electron and the hole mobility ratios of [110]-surface strained-SOI MOSFETs to the universal mobility of (100)-surface bulk-MOSFETs increase up to 81% and 203%, respectively. Therefore, the current drive imbalance between n- and p-MOS can be reduced. Moreover, both the electron and the hole mobilities of the [110]-surface strained-SOIs strongly depend on the drain current flow direction, which is qualitatively explained by the anisotropic effective mass characteristics of the carriers on a [110]-surface Si. As a result, the [110]-surface strained-SOI technology with optimization of the current flow directions of n- and p-MOS is promising for realizing higher speed scaled CMOS.     

Hepatitis GB virus C genome in the serum of aplastic anaemia patients receiving frequent blood transfusions

GB virus C (GBV-C) RNA was detected in five of 18 patients with aplastic anaemia who had received blood transfusions, whereas it was not detected in eight patients who had not received any transfusions. Antibody against hepatitis C virus (anti-HCV) was detected in nine patients in the transfusion group, compared with one of eight who had not received any transfusions. Therefore, the route of transmission of both GBV-C and HCV in these patients appeared to have been multiple blood transfusion. Since all of the GBV-C RNA-positive patients harboured anti-HCV, GBV-C seems to frequently superinfect with HCV. Neither GBV-C nor HCV is likely to have been a causative agent of the anaemia in the cases examined.     

A Study of Shadowing on Indoor Visible-Light Wireless Communication Utilizing Plural White LED Lightings

White LED is considered as a strong candidate for the future lighting technology. We have proposed an optical wireless communication system that employs white LEDs for indoor wireless networks. In this system, LED is used not only as a lighting device, but also as a communication device. The transmitter has large optical power and large emission characteristics to function as lighting device. And the system has specific wireless channel impulse response differing from infrared wireless communication. In this paper, we discuss about shadowing effect on the system utilizing plural LED lightings including the performance of ISI based on the impulse response. We consider the downlink transmission based on TDMA and evaluate the shadowing effect caused by pedestrians with computer simulation. When the shadowing often occurs at 800 Mb/s, the performance of outage call duration rate and blocking rate are improved by using 3 LED lightings compared with 1 or 2 LED lightings. And, we show that the system with the optimal number of the LED lighting is robust against shadowing and can accommodate more calls. Toshihiko Komine was born in Shizuoka, Japan, on November 17, 1978. He received the B.E. and M.E. degrees in Information and Computer Science from Keio University, Yokohama, Japan, in 2001 and 2003 respectively. He is currently studying for the Ph.D. degree at Department of Information and Computer Science, Keio University. His current research interests are optical wireless communications and LED communications. Shinichiro Haruyama is a professor at Department of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama, Japan. He received an M.S. in engineering science from University of California at Berkeley in 1983 and a Ph.D. in computer science from the University of Texas at Austin in 1990. He worked for Bell Laboratories of AT{&}T and Lucent Technologies, U.S.A from 1991 to 1996, and for Sony Computer Science Laboratories, Inc. from 1998 to 2002. His research interests include reconfigurable system, system design automation, wireless communication, and visible light communication. Masao Nakagawa was born in Tokyo, Japan in 1946. He received the B.E., M.E. and Ph.D. degrees in electrical engineering from Keio University, Yokohama, Japan, in 1969, 1971 and 1974 respectively. Since 1973, he has been with the Department of Electrical Engineering, Keio University, where he is now a Professor. His research interests are in CDMA, consumer Communications, Mobile communications, ITS (Intelligent Transport Systems), Wireless Home Networks, and Visible light Communication. He received 1989 IEEE Consumer Electronics Society Paper Award, 1999-Fall Best Paper Award in IEEE VTC, IEICE Achievement Award in 2000, IEICE Fellow Award in 2001. He was the executive committee chairman on International Symposium on Spread Spectrum Techniques and Applications in 1992 and the technical program committee chairman of ISITA (International Symposium on Spread Spectrum Techniques and Applications) in 1994. He is an editor of Wireless Personal Communications and was a guest editor of the special issues on “CDMA Networks I, II, III and IV” published in IEEE JSAC in 1994 (I and II) and 1996 (III and IV). He chairs the Wireless Home Link sub-committee in MMAC (Multimedia Mobile Access Communication Promotion Committee).     

Suppression of photo-induced dilation in cyanide treated hydrogenated amorphous silicon films

Effects of cyanide (CN) treatment with hydrogenated amorphous silicon (a-Si:H) films have been investigated. The decrease of ΔV/V was observed in cyanide treated a-Si:H films and the successive thermal annealing at 200°C after CN treatment induced the further reduction of the ΔV/V. XPS spectra show the indirect evidence that the cyanide species is present within 10 nm from the hydrogenated amorphous silicon surface. The results of CN treatment with a-Si:H solar cells are demonstrated.     

Flexural properties of moldings of rigid polyurethane made by reaction injection molding

Flexural properties of moldings made by Reaction Injection Molding (RIM), which are structural foams consisting of high density skin and low density core, were investigated by three-point bending tests. Two failure modes were observed in bending tests of the moldings made by RIM, and they are classified as follows according to the density ratio of skin layer to core layer: the opposite side of the skin layer to which load was subjected failed by tensile stress: and the same side of the skin layer to which load was subjected failed by compressive stress, causing wrinkling or buckling. Then the conventional composite beam theory was applied to the former failure mode and Hoff s buckling theory to the latter, and equations were derived to predict the flexural properties of the structural foams, which involved buckling from the flexural properties of solid construction. In addition, it has been shown that there exists a density distribution that maximizes the flexural strength of the moldings made by RIM with a given overall density. The results obtained here should be useful to the optimum structural design of moldings made by RIM.     

Comparative study on the assay for IgE antibodies specific for Chamaecyparis obtusa pollen between AlaSTAT and CAP-RAST

Titers of IgE antibody specific for the pollen of Chamaecyparis obtusa (C. obtusa) were determined by AlaSTAT and CAP-RAST in 221 patients with Japanese cedar pollinosis. IgE antibody to C. obtusa tested positive by CAP-RAST at a higher rate (80.5%) than by AlaSTAT (52.6%). The results obtained from the two assays were compared with those from intradermal skin test. CAP-RAST had a higher sensitivity than that of AlaSTAT. Because the two methods showed no differences in the determination of IgE antibody specific for Cryptomeria japonica, the above differences between AlaSTAT and CAP-RAST are surmised to be ascribable to the differences of C. obtusa antigen used in the both assays.     

Screening of Inhibitors Targeting Heat Shock Protein 47 Involved in the Development of Idiopathic Pulmonary Fibrosis

Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is causally related to fibrotic diseases, including idiopathic pulmonary fibrosis. The identification of Compounds that interfere with the HSP47-collagen interaction is essential for the development of relevant therapeutics. Herein, we prepared human HSP47 as a soluble fusion protein expressed in E. coli and established an assay system for HSP47 inhibitor screening. We screened a natural and synthetic Compound library established at Nagasaki University. Among 1023 Compounds, 13 exhibited inhibitory activity against human HSP47, of which three inhibited its function in a dose-dependent manner. Epigallocatechin-3-O-gallate, one of these three Compounds, is a typical polyphenol Compound derived from tea leaves. Structurally related Compounds were synthesized and examined for their activity, revealing a hydroxyl group at A-ring position 5 as important for its activity. The present findings provide valuable insight for the development of natural product-derived therapeutics for fibrotic diseases, including idiopathic pulmonary fibrosis.