Hokkaido University

About: Hokkaido University is a education organization based out in Sapporo, Hokkaidô, Japan. It is known for research contribution in the topics: Population & Catalysis. The organization has 53925 authors who have published 115403 publications receiving 2651647 citations. The organization is also known as: Hokudai & Hokkaidō daigaku.

Deficient of a Clock Gene, Brain and Muscle Arnt-Like Protein-1 (BMAL1), Induces Dyslipidemia and Ectopic Fat Formation

Abstract: A link between circadian rhythm and metabolism has long been discussed. Circadian rhythm is controlled by positive and negative transcriptional and translational feedback loops composed of several clock genes. Among clock genes, the brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) play important roles in the regulation of the positive rhythmic transcription. In addition to control of circadian rhythm, we have previously shown that BMAL1 regulates adipogenesis. In metabolic syndrome patients, the function of BMAL1 is dysregulated in visceral adipose tissue. In addition, analysis of SNPs has revealed that BMAL1 is associated with susceptibility to hypertension and type II diabetes. Furthermore, the significant roles of BMAL1 in pancreatic β cells proliferation and maturation were recently reported. These results suggest that BMAL1 regulates energy homeostasis. Therefore, in this study, we examined whether loss of BMAL1 function is capable of inducing metabolic syndrome. Deficient of the Bmal1 gene in mice resulted in elevation of the respiratory quotient value, indicating that BMAL1 is involved in the utilization of fat as an energy source. Indeed, lack of Bmal1 reduced the capacity of fat storage in adipose tissue, resulting in an increase in the levels of circulating fatty acids, including triglycerides, free fatty acids, and cholesterol. Elevation of the circulating fatty acids level induced the formation of ectopic fat in the liver and skeletal muscle in Bmal1 -/- mice. Interestingly, ectopic fat formation was not observed in tissue-specific (liver or skeletal muscle) Bmal1 -/- mice even under high fat diet feeding condition. Therefore, we were led to conclude that BMAL1 is a crucial factor in the regulation of energy homeostasis, and disorders of the functions of BMAL1 lead to the development of metabolic syndrome.

Torque Density and Efficiency Improvements of a Switched Reluctance Motor Without Rare-Earth Material for Hybrid Vehicles

Abstract: A machine design of a switched reluctance motor having competitive torque and efficiency as well as compactness with respect to an interior permanent-magnet (IPM) synchronous motor (IPMSM) in a hybrid electric vehicle (Toyota Prius 2003) has been investigated. A torque of 400 N·m is set as a target with an outer diameter of 269 mm with an axial length of 156 mm, including coil end lengths. In addition, a 50-kW field weakening capability must be competitive to the IPMSM. The highest efficiency of 95% is also aimed. Stator and rotor structures and iron material are investigated. Test machines are built. Static and light load tests are carried out.

A ten- to 15-year follow-up observation of high tibial osteotomy in medial compartment osteoarthrosis.

Abstract: High tibial osteotomy (HTO) was performed on 86 medially osteoarthritic knees in 78 patients. Twelve patients died during the follow-up period. Fifty-six knees of 51 patients were evaluated twice postoperatively: once at six years after surgery and again after ten to 15 years. Results were satisfactory in 88% of the knees at the six-year follow-up evaluation and in 63% at the post-ten-year follow-up evaluation. Ten-year follow-up results significantly deteriorated. The femorotibial angle (FTA) at the time of bone union after HTO was a significant factor that contributed to the ten-year results. In patients maintaining excellent improvement of knee function at the post-ten-year follow-up evaluation, the mean FTA at one year after surgery was 165 degrees; this value was constant through ten years after HTO. An FTA of 164 degrees-168 degrees should be attained to ensure favorable long-term results in HTO.

Calmodulins from muscles of marine invertebrates, scallop and sea anemone.

Abstract: Invertebrate calmodulins of the sea anemone and scallop muscle were isolated and their properties were compared with those of vertebrate calmodulins from rabbit muscle and pig brain. The molecular weights estimated by SDS-polyacrylamide gel electrophoresis were similar to the molecular weight (16,500) of the vertebrate calmodulins. Every calmodulin contained 1 mol each of trimethyllysine and histidine, and high contents of acidic amino acids. The marine invertebrate calmodulins contained only one tyrosine in contrast to two tyrosines in the vertebrate ones. As a result, the UV absorption spectra were clearly different. The Ca2+-induced difference UV absorption spectra of the invertebrate calmodulins were indistinguishable from those of the vertebrate ones in spite of the difference in tyrosine contents. In tryptic peptide maps of invertebrate calmodulins, a few spots different from those of vertebrate calmodulins were observed in the basic and acidic peptide regions. The calmodulins of invertebrate muscles and that of rabbit skeletal muscle were almost indistinguishable in terms of the activation profile of rabbit skeletal myosin light chain kinase.

Transition Metal Disulfides as Noble-Metal-Alternative Co-Catalysts for Solar Hydrogen Production

Abstract: The production of hydrogen fuels by using sunlight is an attractive and sustainable solution to the global energy and environmental problems. Platinum (Pt) is known as the most efficient co-catalyst in hydrogen evolution reaction (HER). However, due to its high-cost and limited-reserves, it is highly demanded to explore alternative non-precious metal co-catalysts with low-cost and high efficiency. Transition metal disulfides (TMDs) including molybdenum disulfide and tungsten disulfide have been regarded as promising candidates to replace Pt for HER in recent years. Their unique structural and electronic properties allow them to have many opportunities to be designed as highly efficient co-catalysts over various photo harvesting semiconductors. Recent progress in TMDs as photo-cocatalysts in solar hydrogen production field is summarized, focusing on the effect of structural matchability with photoharvesters, band edges tunability, and phase transformation on the improvement of hydrogen production activities. Moreover, recent research efforts toward the TMDs as more energy-efficient and economical co-catalysts for HER are highlighted. Finally, this review concludes by critically summarizing both findings and current perspectives, and highlighting crucial issues that should be addressed in future research activities.