Convergence process with quasi-canonical localized orbital in all-electron SCF calculation on proteins

A convergence process with a new type of localized orbital (LO) is proposed for self-consistent field (SCF) molecular orbital (MO) calculations on proteins. Recently, an all-electron density functional (DF) calculation on cytochrome c was achieved by a convergence method in which the initial electron density of a peptide was constructed by linking the electron density of small peptides. However, its convergence was slow and insufficient in SCF calculations for long peptides. In this paper a new kind of LO called the ‘quasi-canonical localized orbital (QCLO)’ is formulated and a computational process with QCLOs is proposed to improve the SCF convergence. The QCLO is localized in a certain region of a molecule, but it is also the canonical MO of the region. In test calculations on a seven-residue peptide, the error in the initial total energy calculated with QCLOs was about one twentieth of that by cut and paste of the electron density, and the number of SCF iterations was reduced markedly. Future applications of QCLO to big and complex molecules are also discussed.     

Pyrochemical treatment of spent nitride fuels for MA transmutation

Nitride fuels have several advantages including high thermal conductivity and high metal density(like metallic fuels) and high melting point and isotropic crystal structure(like oxide fuels). Since the late 1990 s, the partitioning and transmutation of minor actinides(MA) has been studied to decrease the long-term radio-toxicity of high-level waste and to mitigate the burden of final disposal. Japan Atomic Energy Agency(JAEA) has proposed a dedicated transmutation cycle using an accelerator-driven system(ADS) with nitride fuels containing MA. The nitride fuel cycle we have developed includes a pyrochemical process. Our focus is on the electrolysis of nitride fuels and their refabrication from the recovered actinides; other processes are similar to the technology for metal fuel treatment and have been studied elsewhere. Here, we summarize our activity on the development of the pyrochemical treatment of spent nitride fuels.     

Psoas Muscle Volume and Attenuation are Better Predictors than Muscle Area for Hospital Readmission in Older Patients after Transcatheter Aortic Valve Implantation

Objective: This study aimed to determine whether the psoas muscle volume (PMV) and its muscle attenuation (MA) are associated with hospital readmission after transcatheter aortic valve implantation (TAVI). Method: We included 113 older patients with aortic stenosis who underwent TAVI at Sakakibara Heart Institute (mean age 85 ± 5 years, 69% women). We measured PMV and psoas muscle area (PMA) as well as total muscle area (TMA) at the third lumbar vertebra using preoperative computed tomography (CT) images. The crude values of the PMV, PMA, and TMA were normalized by dividing by height squared. Results: The median follow-up period was 724 days (interquartile range: 528-730 days), and there were 25 all-cause readmissions during the follow-up period (22% of all patients). In the multivariate Cox regression analysis adjusted for age, sex, and EuroSCORE II, the PMV and its MA and crude PMA were significantly associated with all-cause readmission [HR: 0.957 (0.930-0.985), p = 0.003, HR: 0.927 (0.862-0.997), p = 0.040], whereas the PMA and TMA and each MA were not (all p > 0.05). The groups with low PMV and MA had significantly higher incidences of all-cause readmission than that with high PMV and MA (log-rank test: p = 0.011). Conclusion: PMV and its MA measured from preoperative CT images were independent predictors of all-cause readmission in TAVI patients.     

非晶态As_2S_8半导体薄膜的光激励现象的研究及应用

实验研究了非晶态As2S8半导体薄膜在紫外汞灯和He_Cd激光照射下的光诱导现象,证实了光照射后的As2S8薄膜的折射率增大,体积缩小,可见光吸收谱的吸收带蓝移。在此基础上,应用光折变效应试制了As2S8条波导,观测到As2S8条波导的光阻断效应,实现了光_光效应的开关功能。     

LUBAC-mediated linear ubiquitination: a crucial regulator of immune signaling

Ubiquitination is a reversible post-translational modification in which ubiquitin chains are conjugated to target proteins to modulate protein function. The type of ubiquitin chain determines the mode of protein regulation. It has been shown that ubiquitin chains are formed via one of seven Lys residues in ubiquitin, and several types of ubiquitin chains are found in cells. We identified a new type of linear ubiquitin chain linked through the N-terminal Met of ubiquitin and assembled by the linear ubiquitin chain assembly complex (LUBAC), which is specific for linear chains. The discovery of linear ubiquitin chains and LUBAC is considered as a paradigm shift in ubiquitin research because linear ubiquitination is exclusive to animals, despite the existence of ubiquitination throughout eukaryotic kingdoms. Linear ubiquitination plays a critical role in immune signaling and cell death regulation. Dysregulation of LUBAC-mediated linear ubiquitination underlies various human diseases, including autoinflammation, autoimmunity, infection, and malignant tumors. This review summarizes the current status of linear ubiquitination research.