The absorption coefficient and acid generation efficiency are elemental key factors for the design of chemically amplified resist because the acid distribution in resist films is primarily determined by these two factors. In this study, the number of acid molecules generated in a model system of chemically amplified extreme ultraviolet (EUV) resists [poly(4-hydroxystyrene) film dispersed with triphenylsulfonium-triflate (TPS-tf)] was evaluated using an acid sensitive dye. The absorption coefficient and acid generation efficiency were evaluated by changing film thickness. The acid generation efficiency was 1.7 (5 wt % TPS-tf), 2.5 (10 wt % TPS-tf), and 3.1 per photon (20 wt % TPS-tf), respectively. The absorption coefficient of the model film was 3.8±0.2 µm-1. The effect of acid generator concentration on the absorption coefficient of resist films was negligible within the concentration range of 0–20 wt %.

The trade-off between resolution, sensitivity, and line edge roughness (LER) is the most serious problem for the development of sub-30 nm resists based on chemical amplification. Because of this trade-off, the increase in acid generation efficiency is essentially required for high-resolution patterning with high sensitivity and low LER. In this study, we investigated the dependences of acid generation efficiency on the molecular structure and concentration of acid generators upon exposure to extreme ultraviolet (EUV) radiation. The acid generation efficiency (the number of acid molecules generated by a single EUV photon) was obtained within the acid generator concentration range of 0–30 wt % for five types of ionic and nonionic acid generators.

In the RIKEN large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis project we screened mice with a dominant mutation that exhibited abnormal behavior in the open-field test, passive avoidance test and home-cage activity test. We tested 2045 progeny of C57BL/6J males treated with ENU and untreated DBA/2J females in the open-field test and isolated behavioral mutant M100174, which exhibited a significant increase in spontaneous locomotor activity. We identified a missense mutation in the Grin1 gene, which encodes NMDA receptor subunit 1, and designated the mutant gene Grin1(Rgsc174). This mutation results in an arginine to cysteine substitution in the C0 domain of the protein. Detailed analyses revealed that Grin1(Rgsc174) heterozygote exhibited increased novelty-seeking behavior and slight social isolation in comparison with the wild type. In contrast to other Grin1 mutant mice, this mutant exhibited no evidence of heightened anxiety. These results indicate that this is a unique behavioral Grin1 gene mutant mouse that differs from the known Grin1 mutant mice. The results of immunohistochemical and biochemical analyses suggested that impaired interaction between the glutamatergic pathway and dopaminergic pathway may underlie the behavioral phenotypes of the Grin1(Rgsc174) mutant.

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Hypothesis:Steroid avoidance is possible in simultaneous pancreas-kidney transplantation with the use of newer immunosuppressive agents and induction therapy.Design: A retrospective consecutive case review.Setting: A university tertiary referral center.Patients: Medical records of 40 consecutive patients who underwent pancreas-kidney transplantation from November 2000 to July 2002 were reviewed. Intervention:The immunosuppression protocol used in this series of patients consisted of Thymoglobulin induction combined with mycophenolate mofetil, tacrolimus, and sirolimus for maintenance immunosuppression. Steroids were used as pretreatment only, given with Thymoglobulin, and were typically discontinued by postoperative week 1.Main Outcome Measures: Graft and patient survival rates, rejection rates of the kidney or pancreas, infection rates, and surgical complication rates.Results: Patient, kidney, and pancreas survival rates were 95.0%, 92.5%, and 87.5%, respectively. Biopsy-proven pancreas rejection rates at 1 and 3 months' posttransplantation were 2.5%. Kidney rejection rates at 1 and 3 months were 2.5%. Steroids were given only to patients with documented transplant rejection. Surgical and medical complications were no different from earlier protocols.Conclusions: Immunosuppression protocols that do not include maintenance steroids have shown minimal rejection in the first 3 months and equivalent patient and graft survival rates compared with protocols that use steroids. The potential beneficial long-term impact of steroid avoidance will require further study.