27 research outputs found

    Thermoelectric properties of partially filled skutterudites RxCo4Sb12 (R = Ce and Nd) synthesized under high pressures

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    We report the thermoelectric properties of the partially Ce or Nd filled skutterudite compounds CexCo4Sb12 and NdxCo4Sb12 prepared under high pressures and temperatures. The samples were characterized by X-ray diffraction. The actual filling ratio x of Ce or Nd was estimated by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDX). SEM-EDX results indicate that the maximum x values of Ce and Nd can be increased to 0.37 and 0.33, respectively. These values have been considered the highest for any CexCo4Sb12 and NdxCo4Sb12 reported thus far. The electrical resistivity, thermal conductivity, and Seebeck coefficient measurements of the compounds were performed from 5 to 760 K. Furthermore, the Hall coefficient and specific heat of the compounds were also measured below 300 K. The Seebeck and Hall coefficients of both Ce- and Nd-filled samples exhibited the n-type conductor behavior. The maximum dimensionless figure-of-merit (ZT) values of CexCo4Sb12 and NdxCo4Sb12 were determined to be 0.26 and 0.48 at 700K, respectively. (C) 2018 The Japan Society of Applied Physic

    Eating Behavior and Childhood Overweight Among Population-Based Elementary Schoolchildren in Japan

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    This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age) from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects’ sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly), was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls) were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR) for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16–1.94) among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38–2.94) among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts

    The activation mechanism of the aryl hydrocarbon receptor (AhR) by molecular chaperone HSP90

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    The aryl hydrocarbon receptor is a member of the nuclear receptor superfamily that associates with the molecular chaperone HSP90 in the cytoplasm. The activation mechanism of the AhR is not yet fully understood. It has been proposed that after binding of ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3methylcholanthrene (3-MC), or β-naphthoflavone (β-NF), the AhR dissociates from HSP90 and translocates to the nucleus. It has also been hypothesized that the AhR translocates to the nucleus and forms a complex with HSP90 and other co-chaperones. There are a few reports about the direct association or dissociation of AhR and HSP90 due to difficulties in purifying AhR. We constructed and purified the PAS domain from AhR. Binding of the AhR-PAS domain to β-NF affinity resin suggested that it possesses ligand-binding affinity. We demonstrated that the AhR-PAS domain binds to HSP90 and the association is not affected by ligand binding. The ligand 17-DMAG inhibited binding of HSP90 to GST-PAS. In an immunoprecipitation assay, HSP90 was co-immunoprecipitated with AhR both in the presence or absence of ligand. Endogenous AhR decreased in the cytoplasm and increased in the nucleus of HeLa cells 15. min after treatment with ligand. These results suggested that the ligand-bound AhR is translocated to nucleus while in complex with HSP90.We used an in situ proximity ligation assay to confirm whether AhR was translocated to the nucleus alone or together with HSP90. HSP90 was co-localized with AhR after the nuclear translocation. It has been suggested that the ligand-bound AhR was translocated to the nucleus with HSP90. Activated AhR acts as a transcription factor, as shown by the transcription induction of the gene CYP1A1 8. h after treatment with β-NF

    Improvement of look ahead based on quadratic approximation for crystal structure prediction

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    Crystal structure prediction based on first-principles calculations is usually time-consuming since a lot of candidate structures have to be locally optimized. Look Ahead based on Quadratic Approximation, which is one of the selection-type algorithms we previously developed, can control the optimization priority of the candidates. It can efficiently reduce the computational costs in many cases, however, it has been found to be inefficient in some data sets. In the present study, we proposed an improved score of Look Ahead based on Quadratic Approximation, where the stress term is added to overcome the drawbacks of the previous score. Crystal structure prediction simulations by this improved algorithm are performed to investigate the searching efficiency for typical materials such as Si, Al2O3, NaCl, and SrCO3. These results demonstrate that this improved algorithm reduces the searching cost to less than 40% with respect to random search in most cases. The introduction of the stress term makes this algorithm more robust and versatile

    Development of a Knee Joint CT-FEM Model in Load Response of the Stance Phase During Walking Using Muscle Exertion, Motion Analysis, and Ground Reaction Force Data

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    Background and objectives: There are no reports on articular stress distribution during walking based on any computed tomography (CT)-finite element model (CT-FEM). This study aimed to develop a calculation model of the load response (LR) phase, the most burdensome phase on the knee, during walking using the finite element method of quantitative CT images. Materials and Methods: The right knee of a 43-year-old man who had no history of osteoarthritis or surgeries of the knee was examined. An image of the knee was obtained using CT and the extension position image was converted to the flexion angle image in the LR phase. The bone was composed of heterogeneous materials. The ligaments were made of truss elements; therefore, they do not generate strain during expansion or contraction and do not affect the reaction force or pressure. The construction of the knee joint included material properties of the ligament, cartilage, and meniscus. The extensor and flexor muscles were calculated and set as the muscle exercise tension around the knee joint. Ground reaction force was vertically applied to suppress the rotation of the knee, and the thigh was restrained. Results: An FEM was constructed using a motion analyzer, floor reaction force meter, and muscle tractive force calculation. In a normal knee, the equivalent stress and joint contact reaction force in the LR phase were distributed over a wide area on the inner upper surface of the femur and tibia. Conclusions: We developed a calculation model in the LR phase of the knee joint during walking using a CT-FEM. Methods to evaluate the heteromorphic risk, mechanisms of transformation, prevention of knee osteoarthritis, and treatment may be developed using this model
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