Specific induction of hepatocellular adenomas by transplacental administration of ENU in the tsc2 gene mutant (Eker) rat

Recombinant human m-calpain was produced in a soluble form at a level of 20 mg/liter of Sf-9 cell culture by the coexpression of recombinant human m-calpain large (m80K) and small (30K) subunits using a baculovirus expression system. The expressed m-calpain was purified by sequential column chromatographies on DEAE-Toyopearl, gel-filtration, and Mono Q by the same method used to purify native m-calpain. The recombinant m-calpain had a specific activity of 691 U/mg and a Ka value (Ca2+ requirement for 50% caseinolysis activity) of 0.4 mM, which are essentially identical to those of native rabbit m-calpain. A mutant m-calpain large subunit, m-C105S-80K, where the active-site cysteine-105 is converted to serine by site-directed mutagenesis, was coexpressed with 30K in Sf-9 cells, purified, and characterized. m-C105S-calpain does not degrade casein nor an artificial tetra-peptide substrate, succinyl-Leu-Leu-Val-Tyr-MCA. Further, it shows no autolytic activity with Ca2+. This is the first report of the large-scale production of a fully active m-calpain species in the baculovirus system.     

Preparation of B4C-mixed graphite by pressureless sintering and its air oxidation behavior

B₄C-mixed graphites with a boron concentration ranging from 3 to 32 mass% were prepared by pressureless sintering. For fabrications of these materials, a mixture of mesocarbon-microbeads and boron carbide powders was used. Final heat treatment temperature employed was around 2000 °C. The bulk densities of the materials were from 1.78 to 1.85 g/cm³, and the flexural strength was in the range of 44–87 MPa. These materials have a good machinability with shore hardness less than 71. Oxidation loss by air of this material with a total boron concentration more than approx. 10 mass% appeared to be almost completely suppressed at temperatures below 800 °C, where a little weight gain was observed due to the formation of boron oxide. In the temperature range from 900 to 1300 °C, appreciable oxidation loss was observed and the rate decreased as boron concentration increased.     

Correlation between relative number of circulating low-density hepatitis C virus particles and disease activity in patients with chronic hepatitis C

Hepatitis C virus (HCV) circulates as particles having differing buoyant densities. Changes in the relative proportions of virus particles of different densities were examined in 19 patients with chronic hepatitis C: 6 without (group A) and 13 with (group B) abnormal serum alanine aminotransferase (ALT) levels. High- and low-density virus particles were separated by differential flotation centrifugation. The numbers of high-density particles consistently exceeded that of low-density particles in all patients in group A, whereas the titers of both types of particles were the same at least once in 7 of 10 patients sampled at two time points in group B. The ALT level significantly increased <2 months later (P < 0.05) when the titers of both types of particles were the same in patients in group B. Thus, we found a correlation between the relative numbers of circulating low-density HCV particles and disease activity in chronic hepatitis C patients.     

Aging characteristics of AlGaInP/GaInP visible-light lasers (?L = 678 nm)

An aging test for AlGaInP/GaInP visible-light lasers (?L = 678 nm) with 3?5 mW lasing output power was carried out for over 2000 h at room temperature. Significant degradation has not been observed during this test. The results indicate that the AlGaInP laser diodes have a considerable lifetime, suitable for practical use.     

Influence of ion-bombardment-energy on thin zirconium oxide films prepared by dual frequency oxygen plasma sputtering

Thin ZrO₂ films were prepared using dual frequency oxygen reactive plasma sputtering for wear-resistance coating of ceramics products. Influences of ion-bombardment-energy E_i were investigated for improvement of film characteristics. The results revealed that the deposition rate and the hardness of the prepared ZrO₂ thin films gradually increased with increasing E_i for E_i < 220-250 eV and then decreased, whereas the water-contact-angle on ZrO₂ thin films was about 90 °, having a good water-repellent nature.     

Knudson's "two-hit" hypothesis in familial cancer syndromes

Cancer is a heritable disorder of somatic cells. Environment and hereditary both operate in the origin of human cancer. Hereditary cancer is rare, but it has served as a useful model in the understanding of carcinogenesis. A number of cancer genes have been identified by the study of hereditary cancers and implicated in sporadic forms of the same tumors. In this article, I reviewed Knudson's famous "two-hit" hypothesis of tumor suppression.     

Skill-based curiosity for intrinsically motivated reinforcement learning

Machine Learning - Reinforcement learning methods rely on rewards provided by the environment that are extrinsic to the agent. However, many real-world scenarios involve sparse or delayed rewards....     

A high accuracy fluxgate DC current sensor applicable to two-wire electric appliances

Microsystem Technologies - This paper presents a novel high-precision low noise self-oscillating fluxgate DC current sensor that can be used for two-wire measurement. This new sensor mainly...