Quasifermion spectrum at finite temperature from coupled Schwinger-Dyson equations for a fermion-boson system

We nonperturbatively investigate a fermion spectrum at finite temperature in a chiral invariant linear sigma model. Coupled Schwinger-Dyson equations for fermion and boson are developed in the real time formalism and solved numerically. From the coupling of a massless fermion with a massive boson, the fermion spectrum shows a three-peak structure at some temperatures even for the strong coupling region. This means that the three-peak structure which was originally found in the one-loop calculation is stable against higher order corrections even in the strong coupling region.journal articl

脆性材料の損傷許容性評価法の高精度化に関する研究

This article describes the assessment method of the brittle material using the idea of the damage tolerance as a reliability evaluation index. For ceramics the damage torelance nature comes from the local damage of it accompanying nonlinear deformation behavior. The distributed-micro-crack model was developed here to describe the nonlinear behavior of ceramics. Calculated results and experimental ones were in good agreement for the specimens of porous ceramics. So, the damage tolerance of those materials can be evaluate quantitatively using the distributed-micro-crack model. Basic ideas for the distributed-micro-crack model are also included here.textapplication/pdfdepartmental bulletin pape

Role of the guanine nucleotide exchange factor in Akt2-mediated plasma membrane translocation of GLUT4 in insulin-stimulated skeletal muscle

application/pdfCellular Signalling. 2014, 26 (11), P.2460-2469journal articl

項目露出を考慮した整数計画法による等質テスト構成

本論文では，項目露出を考慮した整数計画法による等質テストの自動構成手法を提案する．等質テストとはテストに含まれる項目は異なるが，受験者得点の予測誤差が等質なテスト群である．等質テストでは同一能力の受験者ならば，どのテストを受験しても同一得点となる保証があり，出題可能な項目のデータベース（アイテムバンク）から自動構成される．項目の露出数（出題回数）が大きい項目は受験者間で共有されやすく，経年劣化につながりその項目の信頼性が失われやすいため，露出数の偏りの軽減が重要な課題の一つである． Ishii and Ueno (2015) は構成した等質テストを全て保存し，その中から最も露出率（＝露出数の最大値/テスト構成数）が小さい等質テストを出力して，露出率を軽減する手法を提案した．本論文では乱数を用いた整数計画法でテスト構成することで，露出数の偏りが改善されることを示し，整数計画法のみでは解決されなかった項目露出のバイアス問題を露出数上位の項目をアイテムバンクから除外しながらテスト構成することで解決する手法を提案する．評価実験では従来手法とテスト構成数及び露出率を比較し，提案手法の有効性を示す．journal articl

Observation of B+→ΛΛ̅K+

journal articl

Domain swapping oligomerization of thermostable c-type cytochrome in E. coli cells

Knowledge on domain swapping in vitro is increasing, but domain swapping may not occur regularly in vivo, and its information in cells is limited. Herein, we show that domain-swapped oligomers of a thermostable c-type cytochrome, Hydrogenobacter thermophilus cyt c552, are formed in E. coli which expresses cyt c552. The region containing the N-terminal α-helix and heme was domain-swapped between protomers in the dimer formed in E. coli. The amount of cyt c552 oligomers increased in E. coli as the cyt c552 concentration was increased, whereas that of high-order oligomers decreased in the order of decrease in protein stability, indicating that domain swapping decreases in cells when the protein stability decreases. Apo cyt c552 was detected in the cyt c552 oligomer formed in E. coli, but not in that of the A5F/M11V/Y32F/Y41E/I76V mutant. The cyt c552 oligomer containing its apo protein may form at the periplasm, since the apo protein detected by mass measurements did not contain the signal peptide. These results show that domain-swapped cyt c552 oligomers were formed in E. coli, owing to the stability of the transient oligomer containing the apo protein before heme attachment. This is an indication that exceedingly stable proteins may have disadvantages forming domain-swapped oligomers in cells.journal articl