円形アスペリティで繰り返し発生するすべり: すべり速度・状態依存摩擦法則による数値シミュレーション

I perform numerical simulation of slip process on a two-dimensional planar fault in an infinite uniform elastic medium using a rate- and state-dependent friction law. A circular patch with velocity-weakening frictional property is embedded in the fault, while velocity-strengthening frictional property is assumed in the other region. Simulation results indicate that slip events repeatedly occur at the velocity-weakening patch and slower slip propagates outwards in the velocity-strengthening region. The characteristics of simulated slip on the fault patch are controlled by the ratio of the patch radius r to the critical fault radius rc, which is the critical nucleation patch radius for unstable slip, and is defined as a function of frictional constitutive parameters. When r≫rc, ordinary earthquakes with high slip rates repeatedly occur at the fault patch and postseismic aseismic slip follows on the fault outside the patch. When r～rc, episodic aseismic slip events (silent earthquakes) occur. The rise time of the episodic event increases with a decrease in r/rc. When r≪rc, stable sliding occurs. These results indicate that the rc value can be estimated from geodetically determined values of the fault radius and the source duration of an episodic aseismic slip event

Exhaust behavior of tritium from the large helical device in the first deuterium plasma experiment

The tritium exhaust behavior from the Large Helical Device (LHD) was observed in the first deuterium plasma experimental campaign. Tritium in the exhaust gas was monitored at the conducted by use of the ionization chamber and water bubbler system with the discrimination of chemical forms. The observation results indicated that (i) tritium on the surface of the first wall and divertor tiles as plasma facing components was released by the hydrogen isotope exchange reaction of the glow discharge cleaning operation and the diffusion-limited process was suggested in the tritium release behavior from the bulk, (ii) the amount of tritium release from the LHD vacuum vessel was about one-third of the produced tritium and the mostly produced tritium was still retained at the end of plasma experimental campaign, (iii) the ratio of exhausted tritium from the LHD vacuum vessel was larger than that in the case of JT-60U based on the carbon materials as the plasma-facing components. It indicated that the tritium inventory would be reduced and controlled by the kind of plasma-facing materials

Associations between Comorbidities and Acute Exacerbation of Interstitial Lung Disease after Primary Lung Cancer Surgery

Acute exacerbation (AE) of interstitial lung disease (ILD) is a severe complication of lung resection in lung cancer patients with ILD (LC-ILD). This study aimed to assess the predictive value of comorbidities other than ILD for postoperative AE in patients with LC-ILD. We retrospectively evaluated 68 patients with LC-ILD who had undergone lung resection. We classified them into two groups: those who had developed postoperative AE within 30 days after resection and those who had not. We analyzed patient characteristics, high-resolution computed tomography findings, clinical data, pulmonary function, and intraoperative data. The incidence of postoperative AEs was 11.8%. In univariate analysis, performance status (PS), honeycombing, forced vital capacity (FVC), and high hemoglobin A1c (HbA1c) levels without comorbidities were significantly associated with postoperative AE. Patients were divided into two groups according to cutoff levels of those four variables as determined by receiver operating characteristic curves, revealing that the rates of patients without postoperative AE differed significantly between groups. The present results suggested that preoperative comorbidities other than ILD were not risk factors for postoperative AE in patients with LC-ILD. However, a high preoperative HbA1c level, poor PS, low FVC, and honeycombing may be associated with postoperative AE of LC-ILD

High-resolution cryo-EM structure of photosystem II reveals damage from high-dose electron beams

Photosystem II (PSII) plays a key role in water-splitting and oxygen evolution. X-ray crystallography has revealed its atomic structure and some intermediate structures. However, these structures are in the crystalline state and its final state structure has not been solved. Here we analyzed the structure of PSII in solution at 1.95 Å resolution by single-particle cryo-electron microscopy (cryo-EM). The structure obtained is similar to the crystal structure, but a PsbY subunit was visible in the cryo-EM structure, indicating that it represents its physiological state more closely. Electron beam damage was observed at a high-dose in the regions that were easily affected by redox states, and reducing the beam dosage by reducing frames from 50 to 2 yielded a similar resolution but reduced the damage remarkably. This study will serve as a good indicator for determining damage-free cryo-EM structures of not only PSII but also all biological samples, especially redox-active metalloproteins