The Application of Improved Numerical Techniques to 1-D Micellar/Polymer Flooding Simulation

Three examples of three phase flow models which have been developed are compared under various conditions. Although the dif-ference in oil recovery and surfactant trapping among the models was rather large with constant. salinity, a salinity gradient produced high oil recovery and low surfactant trapping with all three models. Since surfactant trapping is important and it is highly uncertain, this is another reason for designing a micellar flood with a salinity gradient, or something equivalent to a salinity gradient. The semi-discrete method was applied to a 1-D micellar/polymer flooding simulator. By using a semi-discrete method, the time step size can be controlled and varied to be as large as pos-sible without sacrificing accuracy. The stability limit can also be detected with this method. The method is tested and compared with the fully discrete method in various conditions such as differ-ent phase behavior environments and with or without adsorption. In the application of the semi-discrete method, four different ODE in-tegrators were used. Two of them are explicit methods while the other two are implicit methods. Although the implicit methods did not work as well as the explicit methods, there may be some improve-ment possible. With respect to the computation time, one of the explicit methods which is based on the· Runge-Kutta approximation worked best. Although the method can save 20 to 30% computation time under some conditions, compared with the fully-discrete method, the results are highly problem-dependent. To improve the computation time, two methods are suggested. One is to check the error only in the oil or water component rather than all components or any other one component such as surfactant. The other is to check absolute error instead of relative error and multiply by a small conservative factor to the calculated time step size. The stability was analyzed for the oil bank, and for the surfactant front. The former imposes a rather constant limitation on the time step size continuously until the plateau of the oil bank is completely produced: Although approximate, the stability analysis for the surfactant front suggests an unconditional local instability, which is caused by the change in the fractional flow curve due to the surfactant.Petroleum and Geosystems Engineerin

Cytoplasmic tail–dependent internalization of membrane-type 1 matrix metalloproteinase is important for its invasion-promoting activity

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571–572 and Leu578–579) and tyrosine573 residues are important for the internalization, and the μ2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion

Genome sequence analysis of new plum pox virus isolates from Japan

Objective To find mutations that may have recently occurred in Plum pox virus (PPV), we collected six PPV-infected plum/peach trees from the western part of Japan and one from the eastern part. After sequencing the full-length PPV genomic RNAs, we compared the amino acid sequences with representative isolates of each PPV strain. Results All new isolates were found to belong to the PPV-D strain: the six isolates collected from western Japan were identified as the West-Japan strain while the one collected from eastern Japan as the East-Japan strain. Amino acid sequence analysis of these seven isolates suggested that the 1407th and 1529th amino acid residues are characteristic of the West-Japan and the East-Japan strains, respectively. Comparing them with the corresponding amino acid residues of the 47 non-Japanese PPV-D isolates revealed that these amino acid residues are undoubtedly unique. A further examination of the relevant amino acid residues of the other 210 PPV-D isolates collected in Japan generated a new hypothesis regarding the invasion route from overseas and the subsequent diffusion route within Japan: a PPV-D strain might have invaded the western part of Japan from overseas and spread throughout Japan

Cytoplasmic tail-dependent internalization of membrane-type 1 matrix metalloproteinase is important for its invasion-promoting activity

金沢大学自然科学研究科 理化学研究所・横浜研究所　免疫アレルギー科学総合研究センター(RCAI) 横浜市立大学大学院国際総合科学研究科生体超分子科学専攻　客員教授Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571–572 and Leu578–579) and tyrosine573 residues are important for the internalization, and the µ2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion

Tritium and iodine-129 concentrations in precipitation at Tsukuba, Japan, after the Fukushima Daiichi Nuclear Power Plant accident

The earthquake off the Pacific coast of Japan and the subsequent tsunami on March 11, 2011, triggered a series of accidents in the Fukushima Daiichi Nuclear Power Plant (FNPP1). The accidents caused the release of a mixture of radioactive substances into the environment. This study measured the concentration of tritium (3H) and iodine-129 (129I) in rainwater samples collected at Tsukuba, 170 km southwest of the plant, during the year following the accident. High 3H concentrations were observed in the rainwater samples collected within one month after the FNPP1 accident. 3H concentrations decreased steadily over time and returned to the levels before the accident. Concentrations of 129I also decreased over time. However, pulses of high 129I concentrations were observed at several other times following the accident. The 129I concentrations were found to be correlated with iron concentrations in rainwater. It is likely that iron oxide, which can absorb iodate ions (IO3–), was the carrier of radiogenic iodine. This study concludes that 129I and also 131I, which is one of the most harmful radionuclides produced in nuclear reactors, can be redistributed to the atmosphere in the months following the deposition of radiogenic iodine on the ground

BCAA catabolism in brown fat controls energy homeostasis through SLC25A44.

Branched-chain amino acid (BCAA; valine, leucine and isoleucine) supplementation is often beneficial to energy expenditure; however, increased circulating levels of BCAA are linked to obesity and diabetes. The mechanisms of this paradox remain unclear. Here we report that, on cold exposure, brown adipose tissue (BAT) actively utilizes BCAA in the mitochondria for thermogenesis and promotes systemic BCAA clearance in mice and humans. In turn, a BAT-specific defect in BCAA catabolism attenuates systemic BCAA clearance, BAT fuel oxidation and thermogenesis, leading to diet-induced obesity and glucose intolerance. Mechanistically, active BCAA catabolism in BAT is mediated by SLC25A44, which transports BCAAs into mitochondria. Our results suggest that BAT serves as a key metabolic filter that controls BCAA clearance via SLC25A44, thereby contributing to the improvement of metabolic health