Fulde-Ferrell-Larkin-Ovchinnikov state induced by antiferromagnetic order in κ\kappa-type organic conductors

We theoretically investigate superconductivity under a spin-split band structure owing to a collinear-type antiferromagnetic order in quasi-two-dimensional organic compounds $\kappa$-(BEDT-TTF)$_2X$. We find that the magnetic order can induce a Fulde--Ferrell--Larkin--Ovchinnikov (FFLO) state, where the Cooper pair possesses a finite center-of-mass momentum. We show this from two types of analyses: (1) an effective model where simple intraband attractive interactions are assumed, and (2) many-body calculations of the repulsive Hubbard model based on the fluctuation-exchange approximation and the linearized Eliashberg equation. Our results show the possibility of realizing the FFLO state without applying an external magnetic field.Comment: 17 pages, 9 figures; published versio

Statins Activate Human PPARα Promoter and Increase PPARα mRNA Expression and Activation in HepG2 Cells

Statins increase peroxisome proliferator-activated receptor α (PPARα) mRNA expression, but the mechanism of this increased PPARα production remains elusive. To examine the regulation of PPARα production, we examined the effect of 7 statins (atorvastatin, cerivastatin, fluvastatin, pitavastatin, pravastatin, rosuvastatin, and simvastatin) on human PPARα promoter activity, mRNA expression, nuclear protein levels, and transcriptional activity. The main results are as follows. (1) Majority of statins enhanced PPARα promoter activity in a dose-dependent manner in HepG2 cells transfected with the human PPARα promoter. This enhancement may be mediated by statin-induced HNF-4α. (2) PPARα mRNA expression was increased by statin treatment. (3) The PPARα levels in nuclear fractions were increased by statin treatment. (4) Simvastatin, pravastatin, and cerivastatin markedly enhanced transcriptional activity in 293T cells cotransfected with acyl-coenzyme A oxidase promoter and PPARα/RXRα expression vectors. In summary, these data demonstrate that PPARα production and activation are upregulated through the PPARα promoter activity by statin treatment

Contamination of organotin compounds and endocrine disruption in gastropods

Abstracts of 2nd UNU-ORI joint international workshop for marine environment第2回海洋環境国際ワークショップ講演要

有機塩素系溶剤によるアレルギー反応増悪化に関する研究

アレルギー疾患発症・重症化の要因として、ディーゼル排気ガス粒子やホルムアルデヒドなど様々な環境因子の関与が報告されている。本研究では、大気および水質汚染物質である有機塩素系溶剤の中でもトリクロロエチレン(TCE) およびテトラクロロエチレン (PCE) が、肥満細胞からのヒスタミン遊離および炎症性サイトカイン産生を顕著に亢進することを見出した。また水道水質基準値レベルの TCE および PCE をラットに飲水摂取させたところ、肥満細胞のヒスタミン遊離反応亢進と血管周辺への局所的集積を介して I 型アレルギー反応を亢進すると考えられた。また、両化合物は肥満細胞や単核球からの IL-4 や TNF-α 産生を亢進して後期炎症反応の惹起を助長し、さらに Th1/Th2 サイトカインバランスを Th2 側に偏らせることで、アレルギー反応を亢進させているものと考えられた。本研究で得られた知見は、地下水汚染物質として問題となっている有機塩素系溶剤の水道水質基準レベルの摂取がアレルギー反応増悪化・重症化に関与することを示唆するもので、水質管理における衛生学的な見地からも意義深いものである。Many reports show that various environmental pollutants, such as diesel exhaust particles and formaldehyde, are closely related to increases in allergic diseases. In this study, it was found that certain chlorinated organic solvents, in particular trichloroethylene (TCE) and tetrachloroethylene (PCE), which are major air and water pollutants, significantly enhanced histamine release and inflammatory cytokine production from antigen-stimulated mast cells. TCE and/or PCE ingestion from drinking water increased the accumulation of mast cells around the vessel in the skin and histamine release from peritoneal mast cells. These results suggest that low concentration of TCE and PCE leads to acceleration of Type I allergic reaction. TCE and PCE showed increased interleukin (IL)-4 and tumor necrosis factor (TNF)-α production from mast cells and leukocytes which promoted initiation of late-inflammatory responses. TCE and PCE ingestion from drinking water also increased IL-4 production and decreased IFN-γ production. These results suggested that TCE and PCE ingestion aggravate allergic responses via Th1/Th2 cytokine imbalance. Our results suggested that the low concentrations of chlorinated organic solvents, even at Japanese government environmental standards for water and Japanese government drinking water quality guidelines, lead to the initiation and aggravation of allergic reactions. These significant findings are important in hygienic water quality management

Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface

Atomically sharp epitaxial growth of Bi2Se3 films is achieved on Si (111) substrate with MBE (Molecular Beam Epitaxy). Two-step growth process is found to be a key to achieve interfacial-layer-free epitaxial Bi2Se3 films on Si substrates. With a single-step high temperature growth, second phase clusters are formed at an early stage. On the other hand, with low temperature growth, the film tends to be disordered even in the absence of a second phase. With a low temperature initial growth followed by a high temperature growth, second-phase-free atomically sharp interface is obtained between Bi2Se3 and Si substrate, as verified by RHEED (Reflection High Energy Electron Diffraction), TEM (Transmission Electron Microscopy) and XRD (X-Ray Diffraction). The lattice constant of Bi2Se3 is observed to relax to its bulk value during the first quintuple layer according to RHEED analysis, implying the absence of strain from the substrate. TEM shows a fully epitaxial structure of Bi2Se3 film down to the first quintuple layer without any second phase or an amorphous layer.Comment: 20 pages, 7 figure