中碳调质钢焊接区氢致裂纹行为的直接观察

本研究对铬镍系中碳调质钢(SNC631)的高温充氢试件及焊接试件中,氢致裂纹的宏观与微观行为,用光学显微镜及电镜进行了直接观察与记录。并对氢致裂纹萌生及扩展的某些机理,诸如微裂纹与塑性变形的关系,热影响区微裂纹的萌生与硫化物夹杂的关系,以及断裂形式与显微组织的关系等问题,有了进一步的认识。     

Low Cost, Ceria Promoted Perovskite Type Catalysts for Diesel Soot Oxidation

Perovskite type catalysts with SrCoO₃ and Sr_0.8Ce_0.2CoO₃ compositions have been prepared by co-precipitation and other methods and, their catalytic activity towards diesel particulate matter (PM)/carbon oxidation has been evaluated under the loose contact condition. These catalysts show excellent catalytic activity for PM/carbon oxidation, despite their low surface area and under the loose contact condition. The synergistic effects of Ce incorporation in perovskite and presence of a small amount of potassium appears to be responsible for the high soot oxidation activity of these perovskite type materials. The Ce incorporation seems to be contributing by enhancing the redox property of the catalyst, while it appears unlikely that potassium is contributing by improving the catalyst–soot contact through its volatization. The catalysts show excellent thermal stability and stable activity under repeated cycles of use.     

Effect of dietary vitamin E supplementation for one week before slaughter on drip, colour and lipid stability during display in Japanese Black steer beef

Effects of dietary vitamin E supplementation for one week on drip, colour and lipid stability in raw beef steaks were studied. Four Japanese Black steers were fed no supplemental vitamin E and four were supplemented with 5000 mg of dl-α-tocopherol per animal daily for one week before slaughter. Steak samples from psoas major and longissimus thoracis muscles were over-wrapped with PVC film and displayed under fluorescent lights at 4 °C for 10 days. Drip loss percentages, L(?), a(?) and b(?) values, metmyoglobin percentages, and 2-thiobarbituric acid reactive substances values were determined at day 1, 4, 7 and 10. Dietary vitamin E supplementation increased (p < 0.01) α-tocopherol concentration in the plasma, liver and muscles. Vitamin E supplementation reduced (p < 0.001) drip loss compared to the control. Vitamin E supplementation maintained (p < 0.001) redness and retarded (p < 0.01) metmyoglobin formation in beef steak from day 4 to day 10 of display compared to the control. Vitamin E supplementation delayed (p < 0.001) lipid oxidation during 10 days of display compared to the control. The data indicated that dietary vitamin E supplementation for one week prior to slaughter improved lipid stability better than drip and colour stability in beef steak during 10 days of display.     

Formation of poly(vinyl alcohol)–iodine complex in aqueous solution: a SEM study of the freeze-dried substances

The freeze-dried samples prepared from dilute PVA aqueous solutions and PVA–iodine complex aqueous solutions have been examined using a scanning electron microscope. The samples prepared from syndiotacticity-rich PVA (S-PVA) solutions were found to have a network structure due to the formation of intermolecular hydrogen bonds, whereas in the case of atactic PVA (A-PVA) a network structure was not found. The network structure became more finely structured with increasing syndiotacticity. The structure of the freeze-dried sample of the complex solution prepared from S-PVA having a syndiotactic diad content of 63·8%, and iodine, was coarse in comparison with that of the freezedried sample of the S-PVA solution. In addition, the formation of spherical bulges, which are considered to correspond to microgels in the aqueous solution, were observed in several places. In the S-PVA having a syndiotactic diad content of 57·8%, the spherical bulges were not observed, whereas the absorbance of the aqueous solution was the highest. Although A-PVA did not form a PVA– iodine complex at 30°C in solution, the frozen solution turned blue due to the formation of aggregates. These phenomena were confirmed by the degree of crystallinity estimated from IR spectra, and the amount of iodine estimated from X-ray microanalysis of the freeze-dried samples. The PVA–iodine complexes are formed by the interaction of the aggregates of PVA molecules with iodine molecules. However, the PVA microgels do not interact with iodine. © 1998 Society of Chemical Industry     

Functions of Breast Cancer Predisposition Genes: Implications for Clinical Management

Approximately 5–10% of all breast cancer (BC) cases are caused by germline pathogenic variants (GPVs) in various cancer predisposition genes (CPGs). The most common contributors to hereditary BC are BRCA1 and BRCA2, which are associated with hereditary breast and ovarian cancer (HBOC). ATM, BARD1, CHEK2, PALB2, RAD51C, and RAD51D have also been recognized as CPGs with a high to moderate risk of BC. Primary and secondary cancer prevention strategies have been established for HBOC patients; however, optimal preventive strategies for most hereditary BCs have not yet been established. Most BC-associated CPGs participate in DNA damage repair pathways and cell cycle checkpoint mechanisms, and function jointly in such cascades; therefore, a fundamental understanding of the disease drivers in such cascades can facilitate the accurate estimation of the genetic risk of developing BC and the selection of appropriate preventive and therapeutic strategies to manage hereditary BCs. Herein, we review the functions of key BC-associated CPGs and strategies for the clinical management in individuals harboring the GPVs of such genes.     

Testing Method for the Johnson–Mehl–Avrami Equation in Kinetic Analysis of Crystallization Processes

The kinetics of crystallization processes in solids are usually described by the Johnson–Mehl–Avrami equation. One of the most popular methods to test the applicability of this equation is based on a double logarithmic plot of fraction crystallized (α). However, such plot is not very sensitive to small changes in α, and its reliability is rather limited. A simple and convenient testing method based on rate data (dα/d t ) is proposed. The method can be applied to virtually any type of kinetic data obtained under isothermal or nonisothermal conditions.     

Left ventricular function and coagulation activity in healed myocardial infarction

We investigated the plasma levels of molecular markers for the thrombotic and fibrinolytic status in patients with healed myocardial infarction to determine the relation between left ventricular (LV) function and coagulation activity. Our findings demonstrated that the coagulation activity was increased in patients with healed myocardial infarction along with LV dysfunction, suggesting that anticoagulant therapy is considered in patients with severe LV dysfunction to prevent systemic thromboembolism.