Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)-Halide Complexes

Lan Y., Morimoto Y., Shimizu I., et al. Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)-Halide Complexes. Inorganic Chemistry 62, 10539 (2023); https://doi.org/10.1021/acs.inorgchem.3c00320.Structures, physicochemical properties, and reactivity of the whole series of copper(II)-halide complexes (1X; X = F, Cl, Br, and I) were examined using a TMG3tach tridentate supporting ligand consisting of cis,cis-1,3,5-triaminocyclohexane (tach) and N,N,N′,N′-tetramethylguanidine (TMG). The tach ligand framework with the bulky and strongly electron-donating TMG substituents enforces the copper(II) complexes to take a tetrahedral geometry, as inferred from the electron paramagnetic resonance (EPR) spectra, exhibiting relatively large gz and small Az values. The electronic absorption spectra of 1X agreed with the simulation spectra obtained by time-dependent density functional theory (TD-DFT) calculations on a slightly distorted tetrahedral geometry. 1I and 1Br gradually decomposed to generate the corresponding copper(I) complex and halide radical X•, and in the case of 1Br, intramolecular hydroxylation of a methyl group of the TMG substituent took place under aerobic conditions, which may be caused by the reaction of the generated copper(I) complex and dioxygen (O2), generating a reactive oxygen species. 1X except 1I showed hydrogen atom abstraction (HAA) reactivity toward 1,4-cyclohexadiene (CHD), where 1F exhibited the highest reactivity with a second-order rate constant as 1.4 × 10-3 M-1 s-1 at 25 °C. Such an HAA reactivity can be attributed to the higher basicity of F- and/or large bond dissociation free energy of conjugate acid H-F as well as the unstable copper(II) electronic state in the tetrahedral geometry

Ultra-high temperature Soret effect in a silicate melt: SiO2 migration to cold side

The Soret effect, temperature gradient driven diffusion, in silicate melts has been investigated intensively in the earth sciences from the 1980s. The SiO2 component is generally concentrated in the hotter region of silicate melts under a temperature gradient. Here, we report that at ultra-high temperatures above approximately 3000 K, SiO2 becomes concentrated in the colder region of the silicate melts under a temperature gradient. The interior of an aluminosilicate glass (63.3SiO2-16.3Al2O3-20.4CaO(mol%)) was irradiated with a 250 kHz femtosecond laser pulse for local heating. SiO2 migrated to the colder region during irradiation with an 800 pulse (3.2 ms irradiation). The temperature analysis indicated that migration to the colder region occurred above 3060 K. In the non-equilibrium molecular dynamics (NEMD) simulation, SiO2 migrated to the colder region under a temperature gradient, which had an average temperature of 4000 K; this result supports the experimental result. SiO2 exhibited a tendency to migrate to the colder region at 2400 K in both the NEMD and experimental study. The second-order like phase transition was observed at ~ 2000-3400 K when calculated using MD without a temperature gradient. Therefore, the second-order phase transition could be related to the migration of SiO2 to colder region. However, the detailed mechanism has not been elucidated

Spin frustration in antiperovskite systems: (TTF˙+or TSF˙+)3[(Mo6X14)2−Y−]

Two novel antiperovskite charge-transfer (CT) solids composed of a tetraselenafulvalene radical cation (TSF˙+), a dianionic molybdenum cluster unit [Mo6X14]2−, and a halogen anion (Y−) (X, Y = Cl, Br) were prepared by electrocrystallization. Their crystal structures and magnetic properties with regard to spin frustration are discussed together with those of isostructural tetrathiafulvalene (TTF) CT solids previously reported. Both TSF and TTF salts have an apex sharing distorted octahedral spin lattice with a rhombohedral R[3 with combining macron] space group. The calculated overlap integrals based on the crystal structures and insulating nature of the TSF salts indicate that they are Mott insulators. Their spin susceptibilities obeyed the Curie–Weiss law and exhibited an antiferromagnetic ordering at lower temperatures for the TSF salts (Néel temperature, TN = 3.0 K for X = Y = Cl and 5.5 K for X = Y = Br) than the TTF salts. The Curie–Weiss temperatures (|ΘCW| ∼ 1.6–6.3 K) for the TSF salts are lower than those of the TTF salts. For the TSF salts, spin-flop behavior was detected at 3.2 T for X = Y = Cl and 1.5 T for X = Y = Br at 1.9 K. Due to both the distortion of the octahedral geometry of the spin lattice and the anisotropic molecular orientation, the geometrical spin frustrations in TSF and TTF systems are weakened

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

非圧縮性流体解析のための高解像度界面の導入による粒子法の高度化

京都大学0048新制・課程博士博士(工学)甲第22047号工博第4628号新制||工||1722(附属図書館)京都大学大学院工学研究科社会基盤工学専攻(主査)教授 後藤 仁志, 教授 細田 尚, 准教授 KHAYYER,Abbas学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDGA

Pt/Co Alloy Nanoparticles Prepared by Nanocapsule Method Exhibit a High Oxygen Reduction Reaction Activity in the Alkaline Media

Oxygen reduction reaction (ORR) catalysts are one of the main topics for fuel cells and metal/air batteries. We found that the platinum–cobalt alloy nanoparticles prepared by our original nanocapsule method exhibited a high ORR catalytic activity in alkaline solution, compared with that of the existing alloy nanoparticles prepared by different methods. The effect of alloy composition on the ORR activity was investigated to find the optimum composition (approximately 40 atom %). We also found that the enhancement of the catalytic activity in alkaline solution appeared in a very narrow range of Co content compared with that in acidic solution