Pressure-Induced Ferromagnetic to Nonmagnetic Transition and the Enhancement of Ferromagnetic Interaction in the Thiazyl-Based Organic Ferromagnet γ-BBDTA·GaCl4

A thiazyl-based ferromagnet, the γ-phase of BBDTA (i.e., benzo[1,2- d :4,5- d \u27]bis[1,3,2]dithiazole)·GaCl 4 , has a high ferromagnetic ordering temperature of 7.0 K in organic radical ferromagnets. In this system, pressurization generated more compact molecular packing, resulting in that the ferromagnetic state at P = 16.2 kbar is stabilized over a temperature range of more than twice of the initial range. However, the saturation magnetic moment was reduced with increasing pressure, decreasing to about 12% of the initial value even at the low pressure level of P = 1.0 kbar. This suggests that the ferromagnetic molecular packing of the monoclinic γ-phase is easily transformed into that of the diamagnetic phase. Powder X-ray diffraction experiments revealed that the diamagnetic non-monoclinic (α- or β-) phase became stable instead of the monoclinic γ-phase across the pressure of 2.5–5.8 kbar. The increase in the temperature of onset of ferromagnetic state occurs in the surviving ferromagnetic domain surrounded by the diamagnetic domains

Effects of Hydrostatic Pressure and Uniaxial Strain on Spin-Peierls Transition in an Organic Radical Magnet, BBDTA·InCl4

We investigated the effects of hydrostatic pressure and uniaxial strain on the spin-Peierls (SP) transition of an organic radical magnet, benzo[1,2-d:4,5-d\u27]bis[1,3,2]dithiazole(BBDTA)·InCl 4 . It has a one-dimensional coordination polymer structure along its c -axis and its SP transition occurs at 108 K. The SP transition temperature T SP decreased to 99 K at a hydrostatic pressure of 10 kbar, while it increased to 132 K at a uniaxial strain along the c -axis of 8 kbar. The pressure dependences of T SP under these two conditions were discussed by evaluating two parameters, namely, the intrachain interaction 2 J / k B and the effective spin–lattice coupling parameter η, that are related to T SP by the equation T SP =1.6η J / k B . Under ambient pressure, the a - and c -axes of this material shortened monotonically with decreasing temperature, while the b -axis elongated below T SP . In this study, we found the correlation between η and the change in the lattice constant b . 2 J / k B increased with increasing hydrostatic pressure and uniaxial strain, suggesting that the contraction along the c -axis does not depend on the manner of pressurization. From the evaluation of η, the observed variation in T SP is explained by the difference between the changes in b under the two pressurization conditions

Viral RNA recognition by LGP2 and MDA5, and activation of signaling through step-by-step conformational changes

細胞内のウイルスを認識する蛋白質の仕組みを解明 --ウイルスから我々の体を守る影のヒーロー--. 京都大学プレスリリース. 2020-12-04.Cytoplasmic RIG-I-like receptor (RLR) proteins in mammalian cells recognize viral RNA and initiate an antiviral response that results in IFN-β induction. Melanoma differentiation-associated protein 5 (MDA5) forms fibers along viral dsRNA and propagates an antiviral response via a signaling domain, the tandem CARD. The most enigmatic RLR, laboratory of genetics and physiology (LGP2), lacks the signaling domain but functions in viral sensing through cooperation with MDA5. However, it remains unclear how LGP2 coordinates fiber formation and subsequent MDA5 activation. We utilized biochemical and biophysical approaches to observe fiber formation and the conformation of MDA5. LGP2 facilitated MDA5 fiber assembly. LGP2 was incorporated into the fibers with an average inter-molecular distance of 32 nm, suggesting the formation of hetero-oligomers with MDA5. Furthermore, limited protease digestion revealed that LGP2 induces significant conformational changes on MDA5, promoting exposure of its CARDs. Although the fibers were efficiently dissociated by ATP hydrolysis, MDA5 maintained its active conformation to participate in downstream signaling. Our study demonstrated the coordinated actions of LGP2 and MDA5, where LGP2 acts as an MDA5 nucleator and requisite partner in the conversion of MDA5 to an active conformation. We revealed a mechanistic basis for LGP2-mediated regulation of MDA5 antiviral innate immune responses

Association of worker's mental health with changes in exercise time, going‐out time, and screen time (TV time, internet time, and game time) before and after the COVID‐19 pandemic: A cross‐sectional study

Abstract The coronavirus disease 2019 (COVID‐19) pandemic and government regulations have affected the daily lives and mental health of individuals worldwide. This study aimed to determine how much the change in time spent on exercise (exercise time), outdoor activities (“going‐out” time), and screen usage (screen time) before and after the COVID‐19 pandemic has affected mental health (depression, anxiety, and insomnia). In June 2021, during the third wave of the COVID‐19 pandemic, a web‐based, cross‐sectional survey was conducted in Japan through an online research company. A total of 824 workers participated in this study. Depression, anxiety, and insomnia were assessed using the Patient Health Questionnaire‐9, General Anxiety Disorder‐7, and Insomnia Severity Index, respectively. The symptoms of depression were associated with age and decreased exercise time. Symptoms of anxiety were associated with not decreased going‐out time. Symptoms of insomnia were associated with reduced exercise time. The results indicated that during the COVID‐19 pandemic, an increase in exercise time could have prevented depression and insomnia. Similarly, a decrease in going‐out time could have prevented anxiety. Furthermore, in the event of future outbreaks of unpredictable infections, such as COVID‐19, decreased going out and increased exercise may help maintain mental health

Sucutiniranes A and B, new cassane-type diterpenes from Bowdichia nitida

Two new cassane-type diterpenes, sucutiniranes A (1) and B (2), have been isolated from the seeds of Bowdichia nitida together with 6α-acetoxyvouacapane (3) and 6α,7β-diacetoxyvouacapane (4), and the structures of 1 and 2 were elucidated by using 2D NMR data and chemical correlations. Sucutinirane A (1) and 3 showed a moderate cytotoxicity against human colon carcinoma COLO201 cells, and 6α,7β-diacetoxyvouacapane (4) showed in vitro antiplasmodial activity against parasite Plasmodium falciparum 3D7