Tohoku University

About: Tohoku University is a education organization based out in Sendai, Japan. It is known for research contribution in the topics: Magnetization & Population. The organization has 72116 authors who have published 170791 publications receiving 3941714 citations. The organization is also known as: Tōhoku daigaku.

Intraductal papillary mucinous tumors of the pancreas comprise 2 clinical subtypes: differences in clinical characteristics and surgical management.

Abstract: Results: The tumor was located in the head of the pancreas more often in BDT than in MDT (65% [11/17] and 23% [3/13], respectively) Of the 13 patients with MDTs, 12 (92%) had intraductal papillary adenocarcinoma (noninvasive and minimally invasive types) and/or carcinoma in situ (carcinoma in situ: low papillary and/or flat tumor cells), and 3 (23%) had stromal invasion Of the 17 patients with BDTs, 5 (29%) had intraductal papillary adenocarcinoma and/or carcinoma in situ Two pancreatoduodenectomies and 8 pylorus-preserving pancreatoduodenectomies were performed in 10 of the 17 patients with BDTs, distal pancreatectomy in 7 patients with MDTs, and total pancreatectomy in 4 patients with MDTs The 5-year survival rates were 47% for MDT and 90% for BDT Four of 6 patients with MDTs who died had local recurrence One patient died of liver metastasis and 1 of esophageal cancer Only 1 patient with BDT of the 2 who died had recurrent disease Conclusions: Intraductal papillary mucinous tumors may be composed of 2 clinically distinct subtypes: MDTs and BDTs Initially, although distal pancreatectomy can be recommended for most MDTs, the need for cancer-free margins in this more aggressive type may necessitate total pancreatectomy Pylorus-perserving pancreatoduodenectomies is recommended for most BDTs, but, because these tumors are more often adenomas, a good prognosis can be expected Arch Surg 1999;134:1131-1136

On a construction of coordinates at infinity on manifolds with fast curvature decay and maximal volume growth

Abstract: On etudie le comportement asymptotique de varietes de Riemann. On construit des coordonnees a l'infini sous certaines conditions intrinseques

Nrf2 impacts cellular bioenergetics by controlling substrate availability for mitochondrial respiration

Abstract: Transcription factor Nrf2 and its repressor Keap1 regulate a network of cytoprotective genes involving more than 1% of the genome, their best known targets being drug-metabolizing and antioxidant genes. Here we demonstrate a novel role for this pathway in directly regulating mitochondrial bioenergetics in murine neurons and embryonic fibroblasts. Loss of Nrf2 leads to mitochondrial depolarisation, decreased ATP levels and impaired respiration, whereas genetic activation of Nrf2 increases the mitochondrial membrane potential and ATP levels, the rate of respiration and the efficiency of oxidative phosphorylation. We further show that Nrf2-deficient cells have increased production of ATP in glycolysis, which is then used by the F1Fo-ATPase for maintenance of the mitochondrial membrane potential. While the levels and in vitro activities of the respiratory complexes are unaffected by Nrf2 deletion, their activities in isolated mitochondria and intact live cells are substantially impaired. In addition, the rate of regeneration of NADH after inhibition of respiration is much slower in Nrf2-knockout cells than in their wild-type counterparts. Taken together, these results show that Nrf2 directly regulates cellular energy metabolism through modulating the availability of substrates for mitochondrial respiration. Our findings highlight the importance of efficient energy metabolism in Nrf2-mediated cytoprotection.

Development of high tensile strength silicon carbide fibre using an organosilicon polymer precursor

Abstract: THE high tensile strength SiC fibre developed in our laboratory1–5 is extremely heat-resistant and its wettability by metals is good. Metal–matrix composites reinforced with the SiC fibre should therefore be of practical use. Polycarbosilane, the precursor of the fibre, is synthesised by thermal decomposition under high pressure of poly dimethylsilane in an autoclave. To produce the SiC fibre on an industrial scale, polycarbosilane needs to be produced in large quantities with high yield. The autoclave method requires a large amount of space, so the operation is inconvenient and uneconomic. We have, therefore, developed a new method of synthesising the polycarbosilane at normal pressure by adding several wt % of polyborodiphenylsiloxane6 to polydimethylsilane. The structure and properties of the new polycarbosilane, and the SiC fibre obtained from it are described here.

Strength, fracture toughness and Vickers hardness of CeO2-stabilized tetragonal ZrO2 polycrystals (Ce-TZP)

Abstract: Dense Ce-TZP ceramics containing about 7 to 16 mol% CeO2 were fabricated using fine powders prepared by the hydrolysis technique. The mechanical properties of these ceramics were evaluated. The bending strength of sintered bodies with 10 to 12 mol% CeO2 content and small grain-size was about 800 MPa. Fracture toughness was measured by two different methods; a micro-indentation technique and the chevron notched beam technique. A high fracture toughness was obtained for sintered bodies with 7 to 10% CeO2 content and large grain-size. Fracture toughness and hardness were dependent on CeO2 content and grain-size. These mechanical properties are discussed on the basis of the stability of the metastable tetragonal phase depending on CeO2 content and grain-size.