Rheological property of H2O ice VI inferred from its self-diffusion : Implications for the mantle dynamics of large icy bodies

The volume diffusion coefficient of water in ice VI was determined in the pressure-temperature range of 1.3 – 1.9 GPa and 300 – 320 K by in situ isotope tracer diffusion experiments. We determined the activation energy of the volume diffusion to be 61.9 ± 9.5 kJ/mol. The viscosity of polycrystalline ice VI under diffusion creep was estimated from the diffusion coefficients based on the theory of the diffusion creep. From a compilation of viscosity values in the current diffusion creep regime and the viscosity previously determined by plastic deformation experiments of ice VI in a high stress regime (Durham et al. 1996), here we provide the relationships between viscosity, stress, and the average grain size of polycrystalline ice VI. The most plausible deformation mechanism of the layers of ice VI underneath the internal oceans in large icy bodies was inferred from the viscosity-stress-average grain size relationship. We also discuss the critical thickness of the ice VI layer, which determines the onset of thermal convection

Retirement and cardiovascular disease: a longitudinal study in 35 countries

引退すると心疾患リスクが2.2％ポイント減 --35か国約10万人の追跡調査--. 京都大学プレスリリース. 2023-05-29.BACKGROUND: Many countries have been increasing their state pension age (SPA); nonetheless, there is little consensus on whether retirement affects the risk of cardiovascular disease (CVD). This study examined the associations of retirement with CVD and risk factors. METHODS: We used harmonized longitudinal datasets from the Health and Retirement Study and its sister surveys in 35 countries. Data comprised 396 904 observations from 106 927 unique individuals aged 50-70 years, with a mean follow-up period of 6.7 years. Fixed-effects instrumental variable regressions were performed using the SPA as an instrument. RESULTS: We found a 2.2%-point decrease in the risk of heart disease [coefficient = -0.022 (95% confidence interval: -0.031 to -0.012)] and a 3.0%-point decrease in physical inactivity [-0.030 (-0.049 to -0.010)] among retirees, compared with workers. In both sexes, retirement was associated with a decreased heart disease risk, whereas decreased smoking was observed only among women. People with high educational levels showed associations between retirement and decreased risks of stroke, obesity and physical inactivity. People who retired from non-physical labour exhibited reduced risks of heart disease, obesity and physical inactivity, whereas those who retired from physical labour indicated an increased risk of obesity. CONCLUSIONS: Retirement was associated with a reduced risk of heart disease on average. Some associations of retirement with CVD and risk factors appeared heterogeneous by individual characteristics

Isolation and gene analysis of interferon α-resistant cell clones of the hepatitis C virus subgenome

AbstractHepatitis C virus (HCV) proteins appear to play an important role in IFN-resistance, but the molecular mechanism remains unclear. To clarify the mechanism in HCV replicon RNA harboring Huh-7 cells (Huh-9-13), we isolated cellular clones with impaired IFNα-sensitivity. Huh-9-13 was cultured for approximately 2 months in the presence of IFNα, and 4 IFNα-resistant cell clones showing significant resistances were obtained. When total RNA from clones was introduced into Huh-7 cells, the transfected cells also exhibited IFNα-resistance. Although no common mutations were present, mutations in NS3 and NS5A regions were accumulated. Transactivation of IFNα and IFNα-stimulated Stat-1 phosphorylation were reduced, and the elimination of HCV replicon RNA from the clones restored the IFNα signaling. These results suggest that the mutations in the HCV replicon RNA, at least in part, cause an inhibition of IFN signaling and are important for acquisition of IFNα resistance in Huh-9-13

A DISTANCE LEARNING SYSTEM WITH CUSTOMIZABLE SCREEN LAYOUTS FOR MULTIPLE LEARNING SITUATIONS

In this paper, we propose a new distance learning system that can adapt to various styles of learning activity. We assume that the system is used in distance classes with multiple live-streaming videos. Our system has functions to change the screen layout to best suit for the current learning situation for each of the participants in a class. The system also has a function to efficiently monitor the behavior of many students at a time. These functions enable us to adapt various learning activities in distance learning classes. We implemented a prototype of the proposed system and evaluated it in experimental classes. We confirmed that our system improved the activities in the experimental classes

Targeted Disruption in the MouseHoxc-4Locus Results in Axial Skeleton Homeosis and Malformation of the Xiphoid Process

AbstractHoxc-4is a mouse homeobox gene located at the 3′ end of theHoxCcluster. Of theHoxCgenes,Hoxc-4is expressed in the most anterior regions of the central nervous system and prevertebral column. To investigate its role in mouse development, we have generatedHoxc-4mutant mice by gene targeting. Mice homozygous for theHoxc-4mutation are viable and fertile. Analysis of the skeletal system of homozygous mutants revealed various abnormalities in the cervical and thoracic regions. The most frequent abnormality was a partial posterior homeotic transformation of the seventh cervical vertebra. Less frequently, anterior transformations of the third and eighth thoracic vertebrae were observed. Furthermore, the xiphoid process of the sternum was malformed such that it had an aperture or a fissure. AlthoughHoxc-4is expressed abundantly in the central nervous system, no obvious defects were observed. These results suggest thatHoxc-4is required for specifying cervical and thoracic vertebral identity