oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 630 matches for " Masakazu Kohno "
All listed articles are free for downloading (OA Articles)
Page 1 /630
Display every page Item
Effects of a chiral three-nucleon force on nucleus-nucleus scattering
Kosho Minomo,Masakazu Toyokawa,Michio Kohno,Masanobu Yahiro
Physics , 2014, DOI: 10.1103/PhysRevC.90.051601
Abstract: We investigate the effects of chiral NNLO three-nucleon force (3NF) on nucleus-nucleus elastic scattering, using a standard prescription based on the Brueckner-Hartree-Fock method and the g-matrix folding model. The g-matrix calculated in nuclear matter from the chiral N3LO two-nucleon forces (2NF) is close to that from the Bonn-B 2NF. Because the Melbourne group have already developed a practical g-matrix interaction by localizing the nonlocal g-matrix calculated from the Bonn-B 2NF, we consider the effects of chiral 3NF, in this first attempt to study the 3NF effects, by modifying the local Melbourne g-matrix according to the difference between the g-matrices of the chiral 2NF and 2NF+3NF. For nucleus-nucleus elastic scattering, the 3NF corrections make the folding potential less attractive and more absorptive. The latter novel effect is due to the enhanced tensor correlations in triplet channels. These changes reduce the differential cross section at the middle and large angles, improving the agreement with the experimental data for 16O-16O scattering at 70 MeV/nucleon and 12C-12C scattering at 85 MeV/nucleon.
Roles of chiral three-nucleon forces in nucleon-nucleus scattering
Masakazu Toyokawa,Kosho Minomo,Michio Kohno,Masanobu Yahiro
Physics , 2014, DOI: 10.1088/0954-3899/42/2/025104
Abstract: We investigate the roles of chiral three-nucleon force (3NF) in nucleon-nucleus elastic scattering, using the standard framework based on the Brueckner-Hartree-Fock method for nuclear matter and the $g$-matrix folding model for the nucleon-nucleus scattering. In nuclear matter, chiral 3NF at NNLO level (mainly the 2$\pi$-exchange diagram) makes the single particle potential less attractive for the singlet-even channel and more absorptive for the triplet channels. The single-particle potential calculated from chiral two-nucleon force (2NF) at N$^{3}$LO level is found to be close to that from Bonn-B 2NF. The Melbourne $g$-matrix interaction is a practical effective interaction constructed by localizing the $g$-matrices calculated from Bonn-B 2NF. We then introduce the chiral-3NF effects to the local Melbourne $g$-matrix interaction. For nucleon-nucleus elastic scattering on various targets at 65 MeV, chiral 3NF makes the folding potential less attractive and more absorptive. The novel property for the imaginary part is originated in the enhancement of tensor correlations due to chiral 3NF. The two effects are small for differential cross sections and vector analyzing powers at the forward and middle angles where the experimental data are available. If backward measurements are done, the data will reveal the effects of chiral 3NF.
Microscopic calculations based on chiral two- and three-nucleon forces for proton- and $^{4}$He-nucleus scattering
Masakazu Toyokawa,Masanobu Yahiro,Takuma Matsumoto,Kosho Minomo,Kazuyuki Ogata,Michio Kohno
Physics , 2015, DOI: 10.1103/PhysRevC.92.024618
Abstract: We investigate the effects of chiral three-nucleon force (3NF) on proton scattering at 65 MeV and $^{4}$He scattering at 72 MeV/nucleon from heavier targets, using the standard microscopic framework composed of the Brueckner-Hartree-Fock (BHF) method and the $g$-matrix folding model. For nuclear matter, the $g$ matrix is evaluated from chiral two-nucleon force (2NF) of N$^{3}$LO and chiral 3NF of NNLO by using the BHF method. Since the $g$ matrix thus obtained is numerical and nonlocal, an optimum local form is determined from the on-shell and near-on-shell components of $g$ matrix that are important for elastic scattering. For elastic scattering, the optical potentials are calculated by folding the local chiral $g$ matrix with projectile and target densities. This microscopic framework reproduces the experimental data without introducing any adjustable parameter. Chiral-3NF effects are small for proton scattering, but sizable for $^{4}$He scattering at middle angles where the data are available. Chiral 3NF, mainly in the 2$\pi$-exchange diagram, makes the folding potential less attractive and more absorptive for all the scattering.
Preconditioned Iterative Method for Regular Splitting  [PDF]
Toshiyuki Kohno
Advances in Pure Mathematics (APM) , 2017, DOI: 10.4236/apm.2017.72009
Abstract: Several preconditioners are proposed for improving the convergence rate of the iterative method derived from splitting. In this paper, the comparison theorem of preconditioned iterative method for regular splitting is proved. And the convergence and comparison theorem for any preconditioner are indicated. This comparison theorem indicates the possibility of finding new preconditioner and splitting. The purpose of this paper is to show that the preconditioned iterative method yields a new splitting satisfying the regular or weak regular splitting. And new combination preconditioners are proposed. In order to denote the validity of the comparison theorem, some numerical examples are shown.
Mifepristone Promotes Adiponectin Production and Improves Insulin Sensitivity in a Mouse Model of Diet-Induced-Obesity
Takeshi Hashimoto, Junsuke Igarashi, Arif U. Hasan, Koji Ohmori, Masakazu Kohno, Yukiko Nagai, Tetsuo Yamashita, Hiroaki Kosaka
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079724
Abstract: The steroid receptor antagonist mifepristone is used as an anti-cancer agent, eliciting both cytostatic and cytotoxic effects on malignant cells. However, the metabolic effects of long-term treatment with mifepristone have remained unclear. The effects of mifepristone on insulin sensitivity and adiponectin secretion were evaluated both in in vivo and in vitro. First, we explored the effects of mifepristone, on metabolic functions in obese mice receiving a high-fat diet. When these mice were fed mifepristone, they exhibited a marked improvement in insulin sensitivity, attenuated hepatic injury, and decreased adipocyte size, compared with mice that received only the high-fat diet. Intriguingly, mifepristone-treated mice showed significantly elevated plasma adiponectin levels. Second, we tested the effects of mifepristone on differentiated 3T3-L1 adipocytes in vitro. When differentiated adipocytes were treated with mifepristone for 48 h, adiponectin was upregulated at both mRNA and protein levels. Collectively, these results reveal novel actions of mifepristone on metabolic functions, in vivo and in vitro, in which the drug exerts antidiabetic effects associated with an upregulation in adiponectin-secretion.
Galectin-9 Ameliorates Clinical Severity of MRL/lpr Lupus-Prone Mice by Inducing Plasma Cell Apoptosis Independently of Tim-3
Masahiro Moritoki, Takeshi Kadowaki, Toshiro Niki, Daisuke Nakano, Genichiro Soma, Hirohito Mori, Hideki Kobara, Tsutomu Masaki, Masakazu Kohno, Mitsuomi Hirashima
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060807
Abstract: Galectin-9 ameliorates various murine autoimmune disease models by regulating T cells and macrophages, although it is not known what role it may have in B cells. The present experiment shows that galectin-9 ameliorates a variety of clinical symptoms, such as proteinuria, arthritis, and hematocrit in MRL/lpr lupus-prone mice. As previously reported, galectin-9 reduces the frequency of Th1, Th17, and activated CD8+ T cells. Although anti-dsDNA antibody was increased in MRL/lpr lupus-prone mice, galectin-9 suppressed anti-dsDNA antibody production, at least partly, by decreasing the number of plasma cells. Galectin-9 seemed to decrease the number of plasma cells by inducing plasma cell apoptosis, and not by suppressing BAFF production. Although about 20% of CD19?/low CD138+ plasma cells expressed Tim-3 in MRL/lpr lupus-prone mice, Tim-3 may not be directly involved in the galectin-9-induced apoptosis, because anti-Tim-3 blocking antibody did not block galectin-9-induced apoptosis. This is the first report of plasma cell apoptosis being induced by galectin-9. Collectively, it is likely that galectin-9 attenuates the clinical severity of MRL lupus-prone mice by regulating T cell function and inducing plasma cell apoptosis.
The Validity of the Reduction of Disposable Plastic Checkout Bags in Japan  [PDF]
Masakazu Yamashita, Daichi Toyofuku
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.39118
Abstract: This study examined the effect of reducing disposable plastic checkout bags used in supermarkets, convenience stores, and so on in Japan. Considering that even when these checkout bags are abolished, alternative waste bags should be newly produced, because these checkout bags have been reused as household waste bags so far, and the corresponding amount of oil is still necessary to produce them, the amount of oil saved by this bag reduction was found to be 0.2 L/person/year at most. Further, it was demonstrated that the necessity to purchase substitute bags may increase the household and financial burden on consumers.
Possibility of the Benzoic Acids Formation by Oxidation of Benzyl Chlorides in the Sand  [PDF]
Masakazu Yamashita, Masato Hata
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.41014
Abstract:

Seeking the possibility of the formation of benzoic acids from benzyl halides in natural soil, a model oxidation reaction of the halides was carried out in the presence of water and soil in an open air under UV light irradiation. Addition of TiO2 to soil raised the yield of the acid, implying such a metal oxide plays a real catalytic role in this oxidation. By these supplementary experiments, one of the possibilities for the formation of benzoic acids in natural soil from benzyl chlorides was supported.

Dust Resulting from Tire Wear and the Risk of Health Hazards  [PDF]
Masakazu Yamashita, Shohei Yamanaka
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.46059
Abstract:

The present study examined the effects of air pollutants on people’s health, focusing on dust produced from automobile tires while cars drive on roads. The annual volume of dust resulting from tire wear, calculated based on the number of automobiles registered in Japan, was 1747245.4 m3. To put it simply, this translates to approximately 1.4 times the volume of the Tokyo Dome, a famous Japanese baseball stadium. Particulate substances are categorized into three groups depending on their size, and dust resulting from tire wear is classified into the coarse particle mode along with mold spores, pollen, and dust produced from brake pads. This study examined whether or not tire dust causes health damage similarly to pollen, a particulate substance in the same group. There were 38/cm2 dust particles resulting from tire wear on a busy road in Osaka Prefecture, and this number was larger than that of cedar pollen/cm2 (35), a cause of hay fever, identified in Hokkaido. The results suggest that tire dust may also adversely affect the health of people if any of its constituents has a toxicity or causes allergies.

Effects of Heavy Metal Pollution of Apple Orchard Surface Soils Associated with Past Use of Metal-Based Pesticides on Soil Microbial Biomass and Microbial Communities  [PDF]
Masakazu Aoyama, Ryo Tanaka
Journal of Environmental Protection (JEP) , 2013, DOI: 10.4236/jep.2013.44A005
Abstract:

Apple orchard surface soils in Japan are polluted with copper (Cu), lead (Pb), and arsenic (As) due to long-term use of metal-based pesticides. We investigated the effects of heavy metals accumulated in the surface soils in apple orchards on the microbial biomass and the microbial communities. Soil samples were taken from a chestnut orchard (unpolluted control) and five apple orchards with different degrees of heavy metal pollution. Total concentrations of Cu, Pb, and As in soil ranged from 29 to 931 mg/kg, 35 to 771 mg/kg, and 11 to 198 mg/kg, respectively. The amount of microbial biomass carbon expressed on a soil organic carbon basis decreased with increasing concentrations of heavy metals. Thus, the heavy metals that accumulated in apple orchard surface soils had adverse effects on the soil microbial biomass. The analysis of phospholipid fatty acid (PLFA) composition indicated that the microbial community structure had changed because of the pesticide-derived heavy metals in soil. The relative abundance of gram-positive bacterial marker PLFAs increased and that of fungal marker PLFA decreased with increasing concentrations of heavy metals in soil. Denaturing gradient gel electrophoreses targeting the 16S ribosomal RNA gene of bacteria and the 18S ribosomal RNA gene of fungi also showed shifts in the composition of bacterial and fungal communities induced by soil pollution with heavy metals. However, the diversity of microbial communities was not significantly affected by the heavy metal pollution. This was attributable to the adaptation of the microbial communities in apple orchard surface soils to heavy metals derived from previously used pesticides.

Page 1 /630
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.