Heterologous ectoine production in Escherichia coli : By-passing the metabolic bottle-neck

Peer reviewedPublisher PD

Field-dependent exciton dissociation in organic heterojunction solar cells

In organic heterojunction solar cells, the generation of free charge carriers takes place in a multistep process which involves charge transfer (CT) states, that is, bound electron-hole pairs at the interface between donor and acceptor molecules. Past efforts to model the CT-state dissociation during solar cell operation were not able to consistently reproduce the experimentally observed field and temperature dependence. This discrepancy between model and experiment was partly due to the field-dependent free charge carrier collection process, which plays an important role in the widely used bulk heterojunction cell configuration and superimposes a possible field-dependent charge carrier generation process. In order to distinguish between generation and collection of free charge carriers, we propose the planar heterojunction cell configuration as a model system to study the field-dependent charge carrier generation process in organic heterojunction solar cells. We apply this model system to check current CT-state dissociation models against experimental data. Although the models can quantitatively account for the photocurrent's dependence on the applied voltage and the device thickness, they fail to account for the virtually negligible temperature dependence of the field-dependent charge-generation process. This discrepancy is traced back to a common feature of the models: an Arrhenius-like temperature dependence, distinctive of all processes involving a thermally activated jump over an energy barrier. As a solution to the problem, we introduce an exciton dissociation model based on a field-dependent tunnel process and demonstrate its consistency with the experimental observations. Our results indicate that the current microscopic picture of the charge-generation process in organic heterojunction solar cells being limited by the CT-state dissociation process needs to be reconsidered

A numerical and analytical study of two holes doped into the 2D t--J model

Exact diagonalization numerical results are presented for a 32-site square cluster, with two holes propagating in an antiferromagnetic background described by the t-J model. We characterize the wave function of the lowest energy bound state found in this calculation, which has d_{x^2-y^2} symmetry. Analytical work is presented, based on a Lang-Firsov-type canonical transformation derived quasiparticle Hamiltonian, that accurately agrees with numerically determined values for the electron momentum distribution function and the pair correlation function. We interpret this agreement as strong support for the validity of this description of the hole quasiparticles.Comment: 3 pages, REVTeX, to appear in the proceedings of the Fifth International Conference on Spectroscopies in Novel Superconductors, September 14-18, 1997, Cape Cod, Massachusett

Unravelling the adaptation responses to osmotic and temperature stress in Chromohalobacter salexigens, a bacterium with broad salinity tolerance

Chromohalobacter salexigens, a Gammaproteobacterium belonging to the family Halomonadaceae, shows a broad salinity range for growth. Osmoprotection is achieved by the accumulation of compatible solutes either by transport (betaine, choline) or synthesis (mainly ectoine and hydroxyectoine). Ectoines can play additional roles as nutrients and, in the case of hydroxyectoine, in thermotolerance. A supplementary solute, trehalose, not present in cells grown at 37°C, is accumulated at higher temperatures, suggesting its involvement in the response to heat stress. Trehalose is also accumulated at 37°C in ectoine-deficient mutants, indicating that ectoines suppress trehalose synthesis in the wild-type strain. The genes for ectoine (ectABC) and hydroxyectoine (ectD, ectE) production are arranged in three different clusters within the C. salexigens chromosome. In order to cope with changing environment, C. salexigens regulates its cytoplasmic pool of ectoines by a number of mechanisms that we have started to elucidate. This is a highly complex process because (i) hydroxyectoine can be synthesized by other enzymes different to EctD (ii) ectoines can be catabolized to serve as nutrients, (iii) the involvement of several transcriptional regulators (σS, σ32, Fur, EctR) and hence different signal transduction pathways, and (iv) the existence of post-trancriptional control mechanisms. In this review we summarize our present knowledge on the physiology and genetics of the processes allowing C. salexigens to cope with osmotic stress and high temperature, with emphasis on the transcriptional regulation

The Aeginrst Transposal: Part 2

GRISANTE the surname of three individuals listed in the 1992 Erie County TD. Saint GRISANTE is another name for St. Chrysanthu of Daria, according to BMGC

『学生』の聖堂

「ペテロの否み」のエピソードを含むチェーホフの『大学生』の先行研究には、物語の最大の特徴である主人公イワンの極端な内面の変化について、情景（「荒野」「焚き火」「川」「山」等）も含めた精緻な宗教的解釈がすでに多数ある。小論は、三つの根拠： 1) イワンが西から東に移動すること、2) 西から東への移動が、従来個別に解釈されてきた情景（点景）を教会建物イメージに統合すること、3) ゲッセマネの園から続く「鎖」は「二端の鎖」（迷える子羊とイエスの背負った十字架の象徴）であること、に基づき、渡し舟（教会のアナロジー）によるイワンの渡河とその後の登頂は、イコノスタスの王門から至聖所の高所への移行、つまり迷いの克服と修行再開の表明と結論し、従来の宗教的解釈を支持するひとつの論拠を示した。This research was supported by Kansai University\u27s Overseas Research Program for the year of 2014

看護学生による領域別実習指導の評価 -実習初期と後期の比較から－

【目的】看護学生による指導者評価が，領域別実習初期と後期でどのように違いがあるのかを把握し，領域別実習における指導のあり方について検討する．【方法】A 看護系短期大学3 年生64 名を対象に，実習指導の内容と質について評価できるECTB 評価スケールを使用し，看護学生の指導者に対する評価を無記名自記式調査で実施した．データ分析はECTBスケールの質問項目ごとに初期と後期の平均値をt 検定で行い，有意水準は5％未満とした．【結果】前期56 名，後期29 名を分析対象とした結果，ECTB スケール43 項目すべてにおいて後期が低い得点となった．特に『学習意欲への刺激』3 項目，『学生への理解』4 項目，『要素外の項目』1 項目の計8 項目において，p<0.01 ～ 0.05 で後期の方が有意に低い値となった．【考察】これらの結果から実習最後まで学習環境，とくに人的な環境の調整が求められていることが示唆された