Objectives The Tokyo subway sarin attack in 1995 was an unprecedented act of terrorism that killed 13 people and sickened more than 6,000. The long-term somatic and psychological effects on its victims remain unknown. Methods We conducted analyses on the self-rating questionnaire collected annually by the Recovery Support Center (RSC) during the period from 2000 to 2009. The RSC is the only organization that has large-scale follow-up data about sarin attack victims. The prevalence of selfreported symptoms was calculated over 10 years. We also evaluated the prevalence of posttraumatic stress response (PTSR), defined as a score � 25 on the Japanese-language version of the Impact of Event Scale-Revised. The multivariate Poisson regression model was applied to estimate the risk ratios of age, gender, and year factor on the prevalence of PTSR. Results Subjects were 747 survivors (12% of the total) who responded to the annual questionnaire once or more during the study period. The prevalence of somatic symptoms, especially eye symptoms, was 60-80% and has not decreased. PTSR prevalence was 35.1%, and again there was no change with time. The multivariate Poisson regression model results revealed "old age" and "female" as independent risk factors, but the passage of time did not decrease the risk of PTSR.

Nano-structure stiction during drying has often occurred due to scaling of semiconductor devices. For less stiction drying technology, lower surface tension liquids such as isopropyl alcohol (IPA) or super critical fluid (SCF) have been developed, but are lacking in enough performance or maturity for 300 mm leading-edge device wafer treatment. Thus, we have focused on the surface energy reduction process which enables separation of the once adhering structures. We have evaluated the effect of the surface energy on the stiction with both calculation and experimental data, and have successfully demonstrated that the surface energy reduction process can suppress high aspect-ratio nano-structure stiction.

Scaling of semiconductor devices has caused nano-structure stiction issues during the drying step of wafer cleaning. We have already proposed a surface modification process to reduce the surface energy, and we have demonstrated this process is more effective for preventing nano-structure stiction than conventional IPA (isopropyl alcohol) drying. In this paper, the proper molecular structure is investigated for surface modification agents. It is important for the suppression of stiction to reduce a surface free energy rather than to increase a water contact angle. We have attained stiction free drying of a high aspect ratio pattern with 15 nm half pitch line and space using agents with shorter alkyl groups.