78 results on '"Y. Tago"'
Search Results
2. A Simulation of Polymer Electrolyte Fuel Cells with Co-Flow/Counter-Flow Pattern under Dry Condition
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Y. Tago
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Materials science ,Flow (mathematics) ,Chemical engineering ,Counter flow ,Polymer electrolyte fuel cells - Published
- 2004
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3. PIV Web Visualization System toward PIV visualization grid
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Y. Kadooka, Y. Tago, J. W. Choi, Young-Ho Lee, and Hiromichi Kobashi
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Java ,Java servlet ,Computer science ,business.industry ,computer.file_format ,Condensed Matter Physics ,computer.software_genre ,Grid ,Visualization ,Information visualization ,Non-linear editing system ,Computer graphics (images) ,Problem solving environment ,The Internet ,Electrical and Electronic Engineering ,business ,computer ,computer.programming_language - Abstract
To visualize the simulation and experimental data, the fluid dynamics scientists and engineers have to possess a powerful visualization engine with CG package in their laboratories. We developed a Problem Solving Environment (PSE) system called "PIV Web Visualization System" to solve this obstacle, using computational grid common service tool "Globus", programming language Java and Java Servlet. This system has "Grid Portal" which enables us to view the visualization resources on the networks as a unified whole and can be accessed around the world through the Internet, and it combines PIV engine "KMU-PIV" on visualization server in Korea Maritime University with a nonlinear video editing system on Kanazawa University as a real application.
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- 2003
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4. Quest for More Information from Lattice QCD Simulations
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QCD-TARO Collaboration, Ph. de Forcrand, M. Garcí a Pérez, T. Hashimoto, S. Hioki, H. Matsufuru, O. Miyamura, T. Umeda, A. Nakamura, I.-O. Stamatescu, Y. Tago, and T. Takaishi
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Physics ,Particle physics ,Physics and Astronomy (miscellaneous) ,Lattice QCD ,Lattice model (physics) - Published
- 2000
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5. Strange and charmed hadron spectroscopy on a 323 x 48 lattice at β = 6.3
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Atsushi Nakamura, Osamu Miyamura, Ion-Olimpiu Stamatescu, T. Hashimoto, Y. Tago, S. Hioki, M. Fujisaki, M. Okuda, Tetsuya Takaishi, and Ph. de Forcrand
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Quark ,Physics ,Nuclear and High Energy Physics ,Strange quark ,Particle physics ,Meson ,High Energy Physics::Lattice ,Nuclear Theory ,High Energy Physics::Phenomenology ,Lambda baryon ,Charm quark ,Nuclear physics ,Baryon ,Hadron spectroscopy ,High Energy Physics::Experiment ,Vector meson ,Nuclear Experiment - Abstract
The results of meson and baryon spectroscopy composed of charm and strange quarks are reported by the use of quenched Wilson fermions on a 323 x 48 lattice at β = 6.3. Ground state hadrons composed of two or three quarks with different hopping parameters, in a region κ = 0.13 to 0.15, are measured. It is found that their masses are well described by a quadratic polynomial in terms of multi-1/κ variables in this region. Adjusting vector meson mass ratios between (ss), (sc) and (cc), the hopping parameters of strange quark and charm quark are determined to be κs = 0.14999(22) and κc = 0.13548(82) without chiral extrapolation. Masses of not yet observed ssc, scc and ccc baryons in GeV are estimated to be 2.778 ± 0.0]6 (ssc), 3.858 ± 0.015 (scc) for (12)+ and 2.813 ± 0.167 (ssc), 3.869 ± 0.055 (scc) 4.880 ± 0.017 (ccc) for (3/2)+. As for the meson spin splitting structure, the quenched Wilson spectrum is more degenerate in comparison with real hadrons, as already pointed out by many authors.
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- 1996
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6. An International Computer Experiment
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Atsushi Nakamura, Hideo Matsufuru, Osamu Miyamura, T. Hashimoto, Ph. de Forcrand, Y. Tago, K. Akemi, S. Hioki, Ion-Olimpiu Stamatescu, M. Fujisaki, M. Okuda, and Tetsuya Takaishi
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Quantum chromodynamics ,Physics ,Particle physics ,Physics and Astronomy (miscellaneous) ,Computer experiment - Published
- 1996
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7. Quantum chromodynamics simulations on a non-dedicated highly parallel computer
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K. Akemi, Ion-Olimpiu Stamatescu, Atsushi Nakamura, S. Hioki, Osamu Miyamura, T. Hashimoto, Ph. deForcrand, Y. Tago, Tetsuya Takaishi, Hans-Christian Hege, M. Okuda, and M. Fujisaki
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Quantum chromodynamics ,Computer science ,High Energy Physics::Lattice ,General Physics and Astronomy ,Parallel computing ,ComputerSystemsOrganization_PROCESSORARCHITECTURES ,Renormalization group ,Bottleneck ,k-nearest neighbors algorithm ,MIMD ,Hardware and Architecture ,Hadron spectroscopy ,Lattice (order) ,Distributed memory ,Computer Science::Databases ,Computer Science::Distributed, Parallel, and Cluster Computing - Abstract
A parallelization study of Quantum Chromodynamics (QCD) simulation on a non-dedicated MIMD computer, Fujitsu AP1000, is reported. The AP1000 is a highly parallel computer with distributed memory. Data communication is fast not only among the nearest neighbor processing units, but also between widely separated ones. We study SU(3) quenched QCD simulation with lattice sizes of 324 and 323 × 48, on the 512-processor AP1000, and report parallelization techniques and physical results for a renormalization group study and hadron spectroscopy. The AP1000 is efficient for these QCD simulations and shows good performance. A bottleneck occurs in the current simulation as data is passed to the front-end processor for storage.
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- 1995
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8. Does overrelaxed updating in lattice QCD improve critical slowing down?
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Y. Tago, Tetsuya Takaishi, Ion-Olimpiu Stamatescu, Atsushi Nakamura, S. Hioki, Osamu Miyamura, Ph. deForcrand, M. Fujisaki, M. Okuda, T. Hashimoto, and K. Akemi
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Physics ,Quantum chromodynamics ,Nuclear and High Energy Physics ,High Energy Physics::Lattice ,Lattice gauge theory ,Critical phenomena ,Quantum electrodynamics ,Autocorrelation ,Lattice field theory ,Gauge theory ,Lattice QCD ,Critical exponent - Abstract
We study the autocorrelation time of blocked loops on 8 4 , 16 4 and 32 4 lattices in pure SU(3) lattice gauge theory over a wide range of β (= 6/ g 2 ) with high statistics. The critical exponent of integrated autocorrelation time by hybrid overrelaxation updating with fixed mixing ratio is found to be 1.74 ± 0.06. This suggests that the overrelaxation still suffer from critical slowing down toward the continuum limit.
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- 1994
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9. Scaling study of pure SU(3) theory - the QCD-TARO collaboration
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K. Akemi, Ph. de Forcrand, S. Hioki, M. Okuda, Atsushi Nakamura, Tetsuya Takaishi, T. Hashimoto, Y. Tago, Osamu Miyamura, C. Hege, Ion-Olimpiu Stamatescu, and M. Fujisaki
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Quantum chromodynamics ,Nuclear and High Energy Physics ,Theoretical physics ,Range (mathematics) ,Statistical physics ,Scaling ,Computer Science::Distributed, Parallel, and Cluster Computing ,Atomic and Molecular Physics, and Optics ,Mathematics - Abstract
We present very precise results from the MCRG analysis on large lattices performed in the frame of the QCD-TARO collaboration using the highly parallel computer AP1000 of Fujitsu. We find good scaling behavior of pure SU(3) theory with strong non-perturbative effects in the range 6 β
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- 1994
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10. QCD ON THE MASSIVELY PARALLEL COMPUTER AP1000
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Y. Tago, Osamu Miyamura, T. Hashimoto, Ph. de Forcrand, Atsushi Nakamura, T. Takaishi, M. Fujisaki, K. Akemi, S. Hioki, M. Okuda, C. Hege, and Ion-Olimpiu Stamatescu
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Quantum chromodynamics ,Computer science ,High Energy Physics::Phenomenology ,Spectrum (functional analysis) ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Parallel computing ,Computer Science Applications ,Time correlation ,Computational Theory and Mathematics ,High Energy Physics::Experiment ,Massively parallel ,Scaling ,Computer Science::Databases ,Computer Science::Distributed, Parallel, and Cluster Computing ,Mathematical Physics - Abstract
We present the QCD-TARO program of calculations which uses the parallel computer AP1000 of Fujitsu. We discuss the results on scaling, correlation times and hadronic spectrum, some aspects of the implementation and the future prospects.
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- 1993
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11. Granule cell type cerebellar hypoplasia in a beagle dog
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Osamu Katsuta, Minoru Tsuchitani, and Y. Tago
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Male ,Cerebellum ,Pathology ,medicine.medical_specialty ,General Veterinary ,Granule (cell biology) ,Anatomy ,Biology ,Granule cell ,Beagle ,Purkinje Cells ,Dogs ,medicine.anatomical_structure ,Gliosis ,Toxicity ,medicine ,Animals ,Animal Science and Zoology ,Dog Diseases ,medicine.symptom ,Medulla ,Cytoplasmic Vacuolation - Abstract
Cerebellar hypoplasia characterized by severe depletion of granule cells and almost intact Purkinje cells was found in a male 19-month-old beagle dog used in a toxicity study. Microscopically, there was a narrow space lacking granule cells between the row of Purkinje cells and the medulla. Gliosis was not seen in any portion of the cerebellum including this space. No significant changes were seen in the Purkinje cells except for occasional cytoplasmic vacuolation. In the molecular layer and medulla, no histopathological abnormalities were observed.
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- 1993
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12. Monte Carlo renormalization group study at large β in confinement region
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Ph. de Forcrand, Atsushi Nakamura, T. Hashimoto, Ion-Olimpiu Stamatescu, C. Hege, S. Hioki, Osamu Miyamura, Tetsuya Takaishi, M. Okuda, Y. Tago, K. Akemi, and M. Fujisaki
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Physics ,Nuclear and High Energy Physics ,Condensed matter physics ,Lattice (order) ,Monte Carlo method ,Renormalization group ,Scaling ,Atomic and Molecular Physics, and Optics - Abstract
Monte Carlo renormalization group analysis on SU(3) lattice at large β is studied. On 32 4 lattice, coupling shift Δβ is 0.48 ± 0.02 and 0.53 ± 0.02 at β =6.55 and 6.80, where the lattice remains in confinement phase. Δβ is approaching its 2-loop asymptotic scaling value. However, deviation is still 20% and 13% at β =6.55 and 6.80, respectively. We also report high statistics data on 16 4 lattice at β =6.80, giving Δβ = .52 ± 0.03 in the deconfined regime.
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- 1993
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13. Study of spatial size effect in quenched Wilson Hadron spectroscopy at β = 6.3
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Ion-Olimpiu Stamatescu, M. Okuda, T. Hashimoto, Y. Tago, S. Hioki, Atsushi Nakamura, Ph. de Forcrand, M. Fujisaki, Tetsuya Takaishi, Osamu Miyamura, Hans-Christian Hege, and K. Akemi
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Physics ,Nuclear and High Energy Physics ,Particle physics ,High Energy Physics::Lattice ,Hadron spectroscopy ,Hadron ,Spectrum (functional analysis) ,High Energy Physics::Experiment ,Boundary value problem ,Atomic and Molecular Physics, and Optics - Abstract
Quenched Wilson hadron spectroscopy at β = 6.3 has been studied by using parallel computer AP1000. Spectrum of hadrons composed of various combinations of hopping parameters are measured on 32 3 × 48 and 16 3 × 48 lattices. We report results of spatial size effects based on various hadron masses. Dependence on boundary conditions along the temporal direction is also examined and discussed.
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- 1993
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14. Cooperative structural and Peierls transition of indium chains on Si(111)
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Seigo Souma, Y. Tago, Katsuaki Sugawara, Yonghao Sun, Takafumi Sato, Takashi Takahashi, and S. Agario
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Physics ,Condensed matter physics ,Band gap ,Peierls transition ,Photoemission spectroscopy ,Transition temperature ,Inverse photoemission spectroscopy ,chemistry.chemical_element ,Angle-resolved photoemission spectroscopy ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,chemistry ,Energy (signal processing) ,Indium - Abstract
We have performed high-resolution angle-resolved photoemission spectroscopy on quasi-one-dimensional indium chains on the Si(111) surface to study the temperature-induced metal-insulator (MI) transition accompanied by the $4\ifmmode\times\else\texttimes\fi{}1$ to $8\ifmmode\times\else\texttimes\fi{}2$ structural change. The band dispersion near ${E}_{F}$ shows an abrupt change at $120\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, giving a relatively large energy gap compared to the energy scale of the transition temperature. The band dispersion of the $8\ifmmode\times\else\texttimes\fi{}2$ phase shows no discernible temperature evolution, in sharp contrast to the conventional simple Peierls or structural transition. The experimental results suggest that the Peierls instability is important in the MI transition, while other structural effects are cooperatively involved.
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- 2008
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15. Development of Grid Middleware CyberGRIP and Its Applications
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T. Suzuki, K. Miyazwa, T. Yamashita, Y. Tago, and Yoshimasa Kadooka
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Product design ,business.industry ,Computer science ,Distributed computing ,Information technology ,Grid ,Virtualization ,computer.software_genre ,Risk analysis (engineering) ,Grid computing ,Manufacturing ,Middleware (distributed applications) ,New product development ,business ,computer - Abstract
Recently, there have been demands for greater functional diversity and higher performance in the information technology infrastructure. As a result, the complexity and scale of product design in the product development phase have increased. In addition, development periods need to be reduced so products can be marketed sooner. These requirements have rapidly increased the need to simulate and analyze efficiently in order to achieve optimum designs and verification. At the same time, the needs to do massive simulations effectively become large to avoid the risks in financial business. To satisfy these requirements, there are some technical issues to be solved. For this purpose, CyberGRIP has been developed as grid problem solving environments to realize the virtualization of heterogeneous distributed computing resources. This paper describes the detail explanation of CyberGRIP, its concrete applications and results for the product development in manufacturing industries and for the currency option in financial business
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- 2006
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16. Distributed Computing Middleware for Small and Medium-Size Enterprise
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Y. Tago, T. Ohkuma, Y. Kojima, and Y. Suzuki
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business.industry ,Computer science ,Distributed computing ,Usability ,computer.software_genre ,Finite element method ,Visualization ,Data visualization ,Grid computing ,Optimization system ,Middleware (distributed applications) ,business ,Computer resources ,computer - Abstract
A middleware named EnGrid for distributed computing has been developed. The EnGrid employs the notion of pure peer-to-peer (P2P) for ease of use, not for sharing computer resources across the world as in conventional P2P. We have also developed three PSE systems on EnGrid for civil engineering applications: parameter sweep system for finite element method (FEM), parameter optimization system for FEM, and the visualization system for geological sections of 3 dimensional models. We show that the calculation time of these systems can be shortened by distributed computing on EnGrid. Due to its general nature, EnGrid will be useful not only for civil engineering but also in other fields as well
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- 2006
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17. Collaborative Problem Solving Environment 'Desk Side Laboratory'
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Y. Tago, T. Maeda, and Yoshimasa Kadooka
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Collaborative software ,Web browser ,business.industry ,Computer science ,Information technology ,computer.software_genre ,Videoconferencing ,Human–computer interaction ,The Internet ,User interface ,business ,computer ,Reliability (statistics) ,Desk - Abstract
Desk Side Laboratory (DSLab), which allows scientists and engineers in geographically different locations to do state-of-the-art research and development through Internet on their Web browsers, has been developed only using commodity products. It has an easy-to-use user interface. It has been found that, when applied to an optimization design of mobile communication system, DSLab is very useful to determine optimization parameters in real time and can yield the results with high reliability in a short time. It has been expected that DSLab is useful for an interdisciplinary approach of state-of-the-art research and development
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- 2006
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18. Development of New Method of Primer Design Based on Genomewide for SNP Typing under Problem Solving Environment on Grid
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T. Inoue, Y. Tago, T. Oroguchi, I. Tomabechi, and T. Makino
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Computer science ,Computation ,biochemical phenomena, metabolism, and nutrition ,Bioinformatics ,computer.software_genre ,Grid ,Grid computing ,Key (cryptography) ,Problem solving environment ,SNP ,Data mining ,Design methods ,computer ,SNP array - Abstract
How primers are specific to target base sequences containing single nucleotide polymorphism (SNP) is considered as the key to SNP analysis. In this study, we have attempt to develop a high-accuracy primer design. For that purpose, we have developed problem solving environment (PSE) on grid system and established an environment to execute Basic Local Alignment Search Tool (BLAST) genome-widely. We have applied this primer design system in the PSE to drug-metabolizing enzyme and verified that this new design method generated highly accurate primers compared with the existing methods by means of computation and experiment. We have also developed a work/low system for the PSE on the grid system and achieved remarkable improvement in efficiency of the primer design. The new method have achieved more than 10 times efficiency compared with the existing methods
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- 2006
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19. Enhanced hydrogenation and acceptor passivation in Si by pressurized water boiling
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T. Satoh, Y. Otomo, Y. Tago, Y. Ohmura, and N. Terakado
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Physics and Astronomy (miscellaneous) ,Passivation ,Silicon ,Atmospheric pressure ,Chemistry ,Boiling ,Diffusion ,Inorganic chemistry ,chemistry.chemical_element ,Substrate (electronics) ,Acceptor ,Sheet resistance - Abstract
It has been shown that a pressurized water boiling (PWB) at 2 atmospheric pressures and 120 °C in an autoclave vessel accelerates significantly hydrogenation and neutralization of B acceptors in Si. Compared with boiling at atmospheric pressure, PWB reduces more the free‐hole IR absorption and increases more the sheet resistivity in B implanted p+ layer on n‐type substrate. An IR absorption of B–H stretching vibration (∼1907 cm−1) has been detected at 16 K for a p+ layer which was PWB processed for only 6 h. Concentration increase of H‐related species in water and faster diffusion of H in Si at higher temperature may be the cause. In contrast with other hydrogenation techniques, water boiling hardly passivates donors in Si even for 10 h PWB.
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- 1995
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20. MCRG study and renormalized coupling constants
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T. Hashimoto, Y. Tago, O. Miyamura, F. Shoji, S. Hioki, Atsushi Nakamura, Ion-Olimpiu Stamatescu, M. Fujisaki, M. Okuda, Ph. de Forcrand, and Tetsuya Takaishi
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Physics ,Coupling constant ,Nuclear and High Energy Physics ,Quantum mechanics ,Statistical physics ,Blocking (statistics) ,Atomic and Molecular Physics, and Optics - Abstract
We report our analysis of MCRG study where we employ an improved blocking scheme and present our first trial to determine effective coupling constants obtained on the blocked lattices.
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- 1995
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21. Analyzing finite temperature mesonic correlators
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I.O. Stamatescu, T. Hashimoto, Y. Tago, Osamu Miyamura, Atsushi Nakamura, Tetsuya Takaishi, Ph. de Forcrand, S. Hioki, M. Okuda, K. Akemi, and M. Fujisaki
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Physics ,Quantum chromodynamics ,Nuclear and High Energy Physics ,Particle physics ,High Energy Physics::Lattice ,High Energy Physics::Phenomenology ,Nuclear Theory ,Atomic and Molecular Physics, and Optics ,Pion ,Quantum electrodynamics ,Dispersion relation ,High Energy Physics::Experiment ,Nuclear Experiment ,Dispersion (water waves) ,Wave function - Abstract
We discuss problems related to the analysis of finite temperature general mesonic correlators and provide preliminary results on the pion wave function and dispersion law in quenched QCD at T ⋍ 0.9 Tc.
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- 1995
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22. Quenched Wilson hadron spectroscopy on a 323 × 48 lattice at β = 6.3
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T. Hashimoto, Ph. de Forcrand, O. Miyamura, Atsushi Nakamura, T. Takaishi, Ion-Olimpiu Stamatescu, Y. Tago, K. Akemi, S. Hioki, M. Okuda, and M. Fujisaki
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Quark ,Physics ,Nuclear and High Energy Physics ,Particle physics ,Meson ,High Energy Physics::Lattice ,Nuclear Theory ,High Energy Physics::Phenomenology ,Omega baryon ,Atomic and Molecular Physics, and Optics ,Charm quark ,Nuclear physics ,Baryon ,Hadron spectroscopy ,Lattice (order) ,High Energy Physics::Experiment ,Nuclear Experiment - Abstract
We briefly summarize our results of quenched Wilson hadron spectroscopy at β = 6.3 on a 323 × 48 lattice. The spectrum of pseudo scalar and vector mesons, (1/2)+ and (3/2)+ baryons composed of up, down, strange and charm quarks are presented. A decrease of mass splitting between (1/2)+ and (3/2)+ baryons is observed when heavy quark masses increase, as in the case of the mass difference between pseudo scalar and vector masses.
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- 1994
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23. Systematic study of autocorrelation time in pure SU(3) lattice gauge theory
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M. Okuda, T. Hashimoto, K. Akemi, Y. Tago, S. Hioki, Ph. de Forcrand, Ion-Olimpiu Stamatescu, M. Fujisaki, Tetsuya Takaishi, Atsushi Nakamura, and Osamu Miyamura
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Imagination ,Physics ,Nuclear and High Energy Physics ,Chemical substance ,High Energy Physics::Lattice ,media_common.quotation_subject ,High Energy Physics - Lattice (hep-lat) ,Autocorrelation ,FOS: Physical sciences ,Atomic and Molecular Physics, and Optics ,High Energy Physics - Lattice ,Lattice (order) ,Lattice gauge theory ,Mixing ratio ,Exponent ,Statistical physics ,Topological quantum number ,media_common - Abstract
Results of our autocorrelation measurement performed on Fujitsu AP1000 are reported. We analyze (i) typical autocorrelation time, (ii) optimal mixing ratio between overrelaxation and pseudo-heatbath and (iii) critical behavior of autocorrelation time around cross-over region with high statistic in wide range of $\beta$ for pure SU(3) lattice gauge theory on $8^4$, $16^4$ and $32^4$ lattices. For the mixing ratio K, small value (3-7) looks optimal in the confined region, and reduces the integrated autocorrelation time by a factor 2-4 compared to the pseudo-heatbath. On the other hand in the deconfined phase, correlation times are short, and overrelaxation does not seem to matter For a fixed value of K(=9 in this paper), the dynamical exponent of overrelaxation is consistent with 2 Autocorrelation measurement of the topological charge on $32^3 \times 64$ lattice at $\beta$ = 6.0 is also briefly mentioned., Comment: 3 pages of A4 format including 7-figures
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- 1994
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24. Hadron spectroscopy on a 323 × 48 lattice
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Atsushi Nakamura, Jun Makino, K. Akemi, Y. Tago, T. Hashimoto, Hans-Christian Hege, Tetsuya Takaishi, Ion-Olimpiu Stamatescu, M. Fujisaki, Ph. de Forcrand, Osamu Miyamura, M. Okuda, and S. Hioki
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Physics ,Quantum chromodynamics ,Nuclear and High Energy Physics ,Particle physics ,High Energy Physics::Lattice ,Hadron spectroscopy ,Lattice (order) ,Hadron ,Statistical physics ,Massively parallel ,Computer Science::Distributed, Parallel, and Cluster Computing ,Atomic and Molecular Physics, and Optics - Abstract
We report the first results of a hadron spectrum measurement by the QCD_TARO Collaboration with the massively parallel computer AP1000. The main memory of AP1000 is currently 8Gbytes (final goal : 16 Gbytes), which allows us to treat rather large lattices. We measure the quenched Wilson spectrum on a 323 × 48 lattice at β = 6.3. We obtain a good agreement with an empirical curve on the Edinburgh plot.
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- 1992
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25. SU(3) renormalization group study on parallel computer AP1000
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Atsushi Nakamura, Ph. de Forcrand, K. Akemi, Osamu Miyamura, Tetsuya Takaishi, Ion-Olimpiu Stamatescu, M. Fujisaki, Hans-Christian Hege, M. Okada, Y. Tago, Jun Makino, T. Hashimoto, and S. Hioki
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Nuclear and High Energy Physics ,Lattice (order) ,Density matrix renormalization group ,Quantum electrodynamics ,Renormalization group ,Atomic and Molecular Physics, and Optics ,Mathematics ,Mathematical physics - Abstract
We report results of a Monte Crlo renormalization group study with b = 2 blocking on a 34 4 lattice in progress. Δβ at β = 6.8 is consistent with previously obtained values at a large β and is smaller than the two-loop asymptotic value.
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- 1992
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26. Finite Temperature Gauge Theory on Anisotropic Lattices
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Y. Tago, Ph. de Forcrand, T. Hashimoto, Atsushi Nakamura, M. Okuda, M. García Pérez, Hideo Matsufuru, O. Miyamura, M. Fujisaki, Tetsuya Takaishi, S. Hioki, and Ion-Olimpiu Stamatescu
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Quantum chromodynamics ,Physics ,Nuclear and High Energy Physics ,Field (physics) ,Hadron ,High Energy Physics::Phenomenology ,High Energy Physics - Lattice (hep-lat) ,Structure (category theory) ,FOS: Physical sciences ,Atomic and Molecular Physics, and Optics ,Theoretical physics ,High Energy Physics - Lattice ,High Energy Physics::Experiment ,Gauge theory ,Symmetry breaking ,Anisotropy - Abstract
The finite temperature transition of QCD can be seen as a change in the structure of the hadrons and as a symmetry breaking transition -- a change in the structure of the vacuum. These phenomena are observed differently and carry complementary information. We aim at a correlated analysis involving hadronic correlators and the vacuum structure including field and density correlations, both non-trivial questions., Comment: 3 pages, Talk presented at LATTICE96(finite temperature)
- Published
- 1996
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27. THE STRUCTURE OF MESONS NEAR Tc – THE QCD-TARO COLLABORATION –
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K. Akemi, S. Hioki, Y. Tago, M. Fujisaki, M. Okuda, Ph. de Forcrand, Hideo Matsufuru, Ion-Olimpiu Stamatescu, Osamu Miyamura, Tetsuya Takaishi, T. Hashimoto, and Atsushi Nakamura
- Subjects
Physics ,Quantum chromodynamics ,Particle physics ,Meson ,Structure (category theory) - Published
- 1996
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28. Scaling Study of Pure Gauge Lattice QCD by Monte Carlo Renormalization Group Method
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S. Hioki, K. Akemi, de Forcrand P, Osamu Miyamura, Atsushi Nakamura, Y. Tago, T. Hashimoto, Tetsuya Takaishi, Ion-Olimpiu Stamatescu, M. Fujisaki, and M. Okuda
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Physics ,Quantum chromodynamics ,Coupling constant ,High Energy Physics::Lattice ,High Energy Physics - Lattice (hep-lat) ,Lattice field theory ,FOS: Physical sciences ,General Physics and Astronomy ,Lattice QCD ,Renormalization group ,Sigma baryon ,Renormalization ,High Energy Physics - Lattice ,Lattice gauge theory ,Quantum mechanics ,Mathematical physics - Abstract
The scaling behavior of pure gauge SU(3) in the region $\beta=5.85 - 7.60$ is examined by a Monte Carlo Renormalization Group analysis. The coupling shifts induced by factor 2 blocking are measured both on 32$^4$ and 16$^4$ lattices with high statistics. A systematic deviation from naive 2-loop scaling is clearly seen. The mean field and effective coupling constant schemes explain part, but not all of the deviation. It can be accounted for by a suitable change of coupling constant, including a correction term ${\cal O}(g^7)$ in the 2-loop lattice $\beta$-function. Based on this improvement, $\sqrt{\sigma}/\Lambda_{\overline {MS}}^{n_f=0}$ is estimated to be $2.2(\pm 0.1)$ from the analysis of the string tension $\sigma$., Comment: 4 pages of A4 format including 7-postscript figures
- Published
- 1993
29. Autocorrelation in Updating Pure SU(3) Lattice Gauge Theory by the use of Overrelaxed Algorithms
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K. Akemi, Ph. deForcrand, M. Fujisaki, T. Hashimoto, H.C. Hege, S. Hioki, O. Miyamura, A. Nakamura, M. Okuda, I.O. Stamatescu, Y. Tago, and T. Takaishi
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Physics ,Nuclear and High Energy Physics ,Wilson loop ,High Energy Physics - Lattice ,Lattice gauge theory ,Lattice (order) ,High Energy Physics::Lattice ,Autocorrelation ,High Energy Physics - Lattice (hep-lat) ,FOS: Physical sciences ,Algorithm ,Deconfinement ,Atomic and Molecular Physics, and Optics - Abstract
We measure the sweep-to-sweep autocorrelations of blocked loops below and above the deconfinement transition for SU(3) on a $16^4$ lattice using 20000-140000 Monte-Carlo updating sweeps. A divergence of the autocorrelation time toward the critical $\beta$ is seen at high blocking levels. The peak is near $\beta$ = 6.33 where we observe 440 $\pm$ 210 for the autocorrelation time of $1\times 1$ Wilson loop on $2^4$ blocked lattice. The mixing of 7 Brown-Woch overrelaxation steps followed by one pseudo-heat-bath step appears optimal to reduce the autocorrelation time below the critical $\beta$. Above the critical $\beta$, however, no clear difference between these two algorithms can be seen and the system decorrelates rather fast., Comment: 4 pages of A4 format including 6-figures
- Published
- 1992
30. Glomerular lesions in spontaneously occurring diabetic WBN/Kob rats
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Isao Narama, Y. Tago, Osamu Katsuta, Minoru Tsuchitani, and Chitoshi Itakura
- Subjects
Blood Glucose ,Male ,medicine.medical_specialty ,Kidney ,Glomerulonephritis, Membranous ,Fibrin ,Pathology and Forensic Medicine ,Lesion ,Rodent Diseases ,Glomerulopathy ,Diabetes mellitus ,Internal medicine ,medicine ,Chronic Progressive Nephropathy ,Animals ,Diabetic Nephropathies ,General Veterinary ,biology ,business.industry ,Glomerular mesangium ,Age Factors ,Rats, Inbred Strains ,medicine.disease ,Rats, Inbred F344 ,Glomerular Mesangium ,Rats ,Disease Models, Animal ,Endocrinology ,medicine.anatomical_structure ,biology.protein ,Histopathology ,medicine.symptom ,business - Abstract
Glomerular lesions in WBN/Kob male rats with spontaneous diabetes were examined histopathologically. The glomerulopathy caused by diabetes was compared with lesions in chronic progressive nephropathy of non-diabetic SD and F344 male aged rats. Diffuse and global thickening of the mesangial area was observed only in WBN/Kob rats and showed a statistically significant correlation with serum glucose concentrations. Therefore, it suggested that the mesangial thickening was a result of hyperglycaemia. Fibrin cap-like lesions were seen in both WBN/Kob and non-diabetic SD or F344 male rats. The severity of these lesions was closely related to that of chronic progressive nephropathy and, therefore, the fibrin cap-like lesions were considered to be due to the chronic progressive nephropathy.
- Published
- 1991
31. Detection of nongenotoxic hepatocarcinogens in the in vivo rat replicative DNA synthesis (RDS) test using a bromodexyuridine (BrdU)-incorporation technique
- Author
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Y. Otsuka, O. Katsuta, T. Chida, Y. Tago, M. Inoue, M. Tsuchitani, and Makoto Miyagawa
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DNA synthesis ,In vivo ,Chemistry ,Genetics ,Toxicology ,Molecular biology - Published
- 1996
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32. Laser angioplasry with contact ceramic tip
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Toshiya Ono, Kou Imachi, T. Chinzei, M. Asano, Kazuhiko Atsumi, Iwao Fujimasa, Kunihiko Mabuchi, Yuusuke Abe, Kaoru Imanishi, Y. Tago, Akimasa Kouno, and T. Yonezawa
- Subjects
Materials science ,law ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Composite material ,Laser ,law.invention - Published
- 1988
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33. Simulation of full QCD on VP400E by an exact algorithm
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M. Makino, H.C. Hege, Atsushi Nakamura, and Y. Tago
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Quantum chromodynamics ,Physics ,Nuclear and High Energy Physics ,High Energy Physics::Lattice ,Quantum Monte Carlo ,Monte Carlo method ,Atomic and Molecular Physics, and Optics ,Hybrid Monte Carlo ,Exact algorithm ,High Energy Physics::Experiment ,Monte Carlo method in statistical physics ,Diffusion Monte Carlo ,Statistical physics ,Monte Carlo molecular modeling - Abstract
We report results of Monte Carlo simulations of full QCD on a small lattice (4∗∗4) by an exact algorithm at β=4.9, 5.1 and 5.3. We use dynamical Wilson fermions and observe phase transitions which can be interpreted as a confining-deconfining transition; they are accompanied with rapid change of . Performance of our program on VP400E is discussed.
- Published
- 1989
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34. Exocellular mucopolysaccharide closely related to bacterial floc formation
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K Aida and Y Tago
- Subjects
Flocculation ,Rhamnose ,Mannose ,Polysaccharide ,Applied Microbiology and Biotechnology ,chemistry.chemical_compound ,Column chromatography ,Glycosaminoglycans ,chemistry.chemical_classification ,Glucosamine ,Chromatography ,Bacteria ,Sewage ,Ecology ,biology ,Polysaccharides, Bacterial ,Galactose ,Glucose ,Activated sludge ,chemistry ,Biochemistry ,biology.protein ,Exoenzyme ,Water Microbiology ,Research Article ,Food Science ,Biotechnology - Abstract
A bacterium isolated from activated sludge formed a visible floc and also produced an exoenzyme that could bring about deflocculation. Scanning electron microscopic examination revealed that the cells were embedded in a film mesh in the floc, which disappeared after treatment with the deflocculating enzyme. Polysaccharides isolated from the floc were fractionated into three fractions by diethylaminoethyl-Sephadex A-25 column chromatography, whereas those from the free cells were fractionated into only two fractions. The missing fraction was a mucopolysaccharide composed of glucosamine, glucose, mannose, galactose, and rhamnose and was hydrolyzed to oligosaccharides by the deflocculating enzyme. The other two fractions were resistant to the enzyme. These results show that the mesh structure of the floc is dependent on a mucopolysaccharide hydrolyzed by the deflocculating enzyme.
- Published
- 1977
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- View/download PDF
35. Molecular-dynamics simulations for molecular-beam epitaxy: Overlayer growth pattern in two-component Lennard-Jones systems
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Kiyoyuki Terakura, M. Ikeda, Y. Tago, T. Oguchi, M. Mikami, O. Ohtsuki, and K. Hara
- Subjects
Molecular dynamics ,Materials science ,Atomic radius ,Component (thermodynamics) ,Chemical physics ,Incident beam ,Substrate (electronics) ,Epitaxy ,Molecular beam epitaxy ,Overlayer - Abstract
Molecular dynamics simulations were performed in order to simulate the process of the molecular-beam epitaxy for two-component Lennard-Jones systems where the atomic size of the incident beam is different from that of the substrate. A drastic but systematic change is observed in the overlayer growth pattern as the size difference changes. Effects of the substrate temperature on the overlayer growth pattern are also studied.
- Published
- 1989
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36. Coronary laser angioplasty with excimer laser
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M. Asano, T. Chinzei, Ichiro Sogawa, Masayuki Suzukawa, Kazuhiko Atsumi, Toshiya Ono, Koro Yotsuya, S. Kanazawa, T. Uemiya, Shin-ichiro Niwa, Iwao Fujimasa, Kunihiko Mabuchi, Akimasa Kouno, Kaoru Imanishi, Yuusuke Abe, Y. Tago, T. Yonezawa, and Kou Imachi
- Subjects
Optics ,Materials science ,Excimer laser ,business.industry ,medicine.medical_treatment ,Laser Angioplasty ,medicine ,business - Published
- 1988
- Full Text
- View/download PDF
37. Apparatus to study fatigue process using high amplitude internal friction technique
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Y Tago, H Mizubayashi, and S Okuda
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Materials science ,High amplitude ,education ,General Engineering ,Process (computing) ,food and beverages ,General Physics and Astronomy ,musculoskeletal system ,Internal friction ,General Materials Science ,sense organs ,Composite material ,skin and connective tissue diseases ,Instrumentation ,Elastic modulus - Abstract
An automatic apparatus to study a fatigue process has been developed in which changes in internal friction and elastic modulus of specimens can be measured in situ during the progress of fatigue.
- Published
- 1984
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- View/download PDF
38. Mean spherical model for the square-well potential
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Y. Tago and K. Narasimha Swamy
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Spherical model ,Physics ,Mathematical analysis ,Finite potential well ,General Physics and Astronomy ,Potential of mean force ,Radial distribution function ,Energy (signal processing) - Abstract
The mean spherical model (MSM) equation has been solved for the aquare-well potential. Comparison of the MSM results with the simulation results shows the MSM radial distribution function and energy to be satisfactory in the liquid states.
- Published
- 1973
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39. Corrigendum to "On-site fabrication of bi-layered adhesive mesenchymal stromal cell dressings for the treatment of heart failure" [Biomaterials 209 (2019) 41-53].
- Author
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Kobayashi K, Ichihara Y, Sato N, Umeda N, Fields L, Fukumitsu M, Tago Y, Ito T, Kainuma S, Podaru M, Lewis-McDougall F, Yamahara K, Uppal R, and Suzuki K
- Published
- 2024
- Full Text
- View/download PDF
40. Effect of Continuous Feeding of Ayu-Narezushi on Lipid Metabolism in a Mouse Model of Metabolic Syndrome.
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Nishida T, Tsuneyama K, Tago Y, Nomura K, Fujimoto M, Nakajima T, Noguchi A, Minamisaka T, Hatta H, and Imura J
- Subjects
- Acyl-CoA Oxidase biosynthesis, Acyl-CoA Oxidase genetics, Animals, Body Weight, Carnitine O-Palmitoyltransferase biosynthesis, Carnitine O-Palmitoyltransferase genetics, Cholesterol blood, Dyslipidemias diet therapy, Dyslipidemias genetics, Enzyme Induction, Fatty Acids metabolism, Gene Expression Regulation, Intra-Abdominal Fat chemistry, Intra-Abdominal Fat pathology, Japan, Liver metabolism, Metabolic Syndrome blood, Metabolic Syndrome genetics, Mice, Mice, Obese, Obesity diet therapy, Obesity genetics, Oryza, Oxidation-Reduction, PPAR alpha biosynthesis, PPAR alpha genetics, Real-Time Polymerase Chain Reaction, Sodium Chloride, Triglycerides blood, Disease Models, Animal, Fermented Foods, Lipid Metabolism, Metabolic Syndrome diet therapy, Osmeriformes
- Abstract
Ayu-narezushi , a traditional Japanese fermented food, comprises abundant levels of lactic acid bacteria (LAB) and free amino acids. This study aimed to examine the potential beneficial effects of ayu-narezushi and investigated whether ayu-narezushi led to improvements in the Tsumura Suzuki obese diabetes (TSOD) mice model of spontaneous metabolic syndrome because useful LAB are known as probiotics that regulate intestinal function. In the present study, the increased body weight of the TSOD mice was attenuated in those fed the ayu-narezushi -comprised chow ( ayu-narezushi group) compared with those fed the normal rodent chow (control group). Serum triglyceride and cholesterol levels were significantly lower in the Ayu-narezushi group than in the control group at 24 weeks of age. Furthermore, hepatic mRNA levels of carnitine-palmitoyl transferase 1 and acyl-CoA oxidase, which related to fatty acid oxidation, were significantly increased in the ayu-narezushi group than in the control group at 24 weeks of age. In conclusion, these results suggested that continuous feeding with ayu-narezushi improved obesity and dyslipidemia in the TSOD mice and that the activation of fatty acid oxidation in the liver might contribute to these improvements., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Takeshi Nishida et al.)
- Published
- 2021
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41. Human amnion-derived mesenchymal stem cells attenuate xenogeneic graft-versus-host disease by preventing T cell activation and proliferation.
- Author
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Tago Y, Kobayashi C, Ogura M, Wada J, Yamaguchi S, Yamaguchi T, Hayashi M, Nakaishi T, Kubo H, and Ueda Y
- Subjects
- Animals, B7-H1 Antigen genetics, B7-H1 Antigen metabolism, CD8-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes metabolism, Cytokines metabolism, Disease Models, Animal, Disease Progression, Graft vs Host Disease etiology, Graft vs Host Disease pathology, Heterografts, Humans, Immunohistochemistry, Mesenchymal Stem Cell Transplantation methods, Mice, Programmed Cell Death 1 Ligand 2 Protein genetics, Programmed Cell Death 1 Ligand 2 Protein metabolism, Treatment Outcome, Amnion cytology, Graft vs Host Disease prevention & control, Lymphocyte Activation immunology, Mesenchymal Stem Cells cytology, Mesenchymal Stem Cells metabolism, T-Lymphocytes immunology, T-Lymphocytes metabolism
- Abstract
Acute graft-versus-host disease (GVHD) is characterized by severe tissue damage that is a life-threatening complication of allogeneic hematopoietic stem cell transplantation. Due to their immunosuppressive properties, mesenchymal stem cells (MSC) have been increasingly examined for the treatment of immune-related diseases. We aimed to assess the immunosuppressive effects of human amnion-derived MSC (AMSC) in a xenogeneic GVHD NOD/Shi-scid IL2rγnull mouse model using human peripheral blood mononuclear cells (PBMC). Additionally, we used human bone marrow-derived MSC (BMSC) as comparative controls to determine differences in immunomodulatory functions depending on the MSC origin. Administration of AMSC significantly prolonged survival, and reduced human tumor necrosis factor-α (TNF-α) concentration and percentage of programmed cell death protein-1 receptor (PD-1)
+ CD8+ T cell populations compared with in GVHD control mice. Furthermore, colonic inflammation score and percentage of human CD8+ T cell populations in AMSC-treated mice were significantly lower than in GVHD control and BMSC-treated mice. Interestingly, gene expression and protein secretion of the PD-1 ligands were higher in AMSC than in BMSC. These findings are the first to demonstrate that AMSC exhibit marked immunosuppression and delay acute GVHD progression by preventing T cell activation and proliferation via the PD-1 pathway.- Published
- 2021
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- View/download PDF
42. High Li-Ion Conductivity in Li{N(SO 2 F) 2 }(NCCH 2 CH 2 CN) 2 Molecular Crystal.
- Author
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Tanaka K, Tago Y, Kondo M, Watanabe Y, Nishio K, Hitosugi T, and Moriya M
- Abstract
There is an urgent need to develop solid electrolytes based on organic molecular crystals for application in energy devices. However, the quest for molecular crystals with high Li-ion conductivity is still in its infancy. In this study, the high Li-ion conductivity of a Li{N(SO
2 F)2 }(NCCH2 CH2 CN)2 molecular crystal is reported. The crystal shows a Li-ion conductivity of 1 × 10-4 S cm-1 at 30 °C and 1 × 10-5 S cm-1 at -20 °C, with a low activation energy of 28 kJ mol-1 . The conductivity at 30 °C is one of the highest values attainable by molecular crystals, whereas that at -20 °C is approximately 2 orders of magnitude higher than previously reported values. Furthermore, the all-solid-state Li-battery fabricated using this solid electrolyte demonstrates stable cycling, thereby maintaining 90% of the initial capacity after 100 charge-discharge cycles. The finding of high Li-ion conductivity in molecular crystals paves the way for their application in all-solid-state Li-batteries.- Published
- 2020
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- View/download PDF
43. A chronic toxicity study of diphenylarsinic acid in the drinking water of C57BL/6J mice for 52 weeks.
- Author
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Yamaguchi T, Gi M, Fujioka M, Tago Y, Kakehashi A, and Wanibuchi H
- Abstract
Diphenylarsinic acid (DPAA), a neurotoxic organic arsenical, is present in the groundwater and soil in some regions of Japan due to illegal dumping. The purpose of the present study was to evaluate the potential toxicity of DPAA when administered to mice in their drinking water for 52 weeks. DPAA was administered to mice at concentrations of 0, 6.25, 12.5, and 25 ppm in their drinking water for 52 weeks. There were no significant differences in final body weights between the control groups and the DPAA treatment groups in male or female mice. Relative liver weights were significantly increased in males treated with 25 ppm DPAA, and absolute liver weights were significantly decreased in female mice treated with 25 ppm DPAA. In female mice, cholangitis and simple bile duct hyperplasia were observed in the 12.5 and 25 ppm DPAA groups, and focal necrosis of hepatocytes was observed in the 25 ppm DPAA group. Proteomic analysis and Ingenuity Pathway Analysis identified 18 proteins related to hepatotoxicity that were overexpressed in the female 25 ppm group. The phase I metabolic enzyme CYP2E1 was one of these overexpressed proteins. Immunostaining confirmed high expression of CYP2E1 in the livers of females in the 25 ppm group. These results suggest that DPAA is toxic to the intrahepatic bile duct epithelium and hepatocytes in female mice and that CYP2E1 might be involved in DPAA-associated toxicity. The no-observed-adverse-effect levels of DPAA were 12.5 ppm (1.6 mg/kg bw/day) for males and 6.25 ppm (1.1 mg/kg bw/day) for females under the conditions of this study.
- Published
- 2019
- Full Text
- View/download PDF
44. On-site fabrication of Bi-layered adhesive mesenchymal stromal cell-dressings for the treatment of heart failure.
- Author
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Kobayashi K, Ichihara Y, Sato N, Umeda N, Fields L, Fukumitsu M, Tago Y, Ito T, Kainuma S, Podaru M, Lewis-McDougall F, Yamahara K, Uppal R, and Suzuki K
- Subjects
- Animals, Bioengineering methods, Blotting, Western, Cardiomyopathies metabolism, Cardiomyopathies pathology, Cells, Cultured, Female, Flow Cytometry, Humans, Hydrogen Peroxide pharmacology, Mesenchymal Stem Cell Transplantation, Mesenchymal Stem Cells drug effects, Myocardium cytology, Myocardium metabolism, Pregnancy, Rats, Reverse Transcriptase Polymerase Chain Reaction, Tissue Scaffolds, Heart Failure therapy, Mesenchymal Stem Cells cytology
- Abstract
Mesenchymal stromal/stem cell (MSC)-based therapy is a promising approach for the treatment of heart failure. However, current MSC-delivery methods result in poor donor cell engraftment, limiting the therapeutic efficacy. To address this issue, we introduce here a novel technique, epicardial placement of bi-layered, adhesive dressings incorporating MSCs (MSC-dressing), which can be easily fabricated from a fibrin sealant film and MSC suspension at the site of treatment. The inner layer of the MSC dressing, an MSC-fibrin complex, promptly and firmly adheres to the heart surface without sutures or extra glues. We revealed that fibrin improves the potential of integrated MSCs through amplifying their tissue-repair abilities and activating the Akt/PI3K self-protection pathway. Outer collagen-sheets protect the MSC-fibrin complex from abrasion by surrounding tissues and also facilitates easy handling. As such, the MSC-dressing technique not only improves initial retention and subsequent maintenance of donor MSCs but also augment MSC's reparative functions. As a result, this technique results in enhanced cardiac function recovery with improved myocardial tissue repair in a rat ischemic cardiomyopathy model, compared to the current method. Dose-dependent therapeutic effects by this therapy is also exhibited. This user-friendly, highly-effective bioengineering technique will contribute to future success of MSC-based therapy., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2019
- Full Text
- View/download PDF
45. Chronic dietary toxicity and carcinogenicity studies of dammar resin in F344 rats.
- Author
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Gi M, Fujioka M, Yamano S, Kakehashi A, Oishi Y, Okuno T, Yukimatsu N, Yamaguchi T, Tago Y, Kitano M, Hayashi SM, and Wanibuchi H
- Subjects
- Animals, Apoptosis drug effects, Body Weight drug effects, Carcinogenicity Tests methods, Chemical and Drug Induced Liver Injury etiology, Chemical and Drug Induced Liver Injury pathology, Dose-Response Relationship, Drug, Female, Food Additives administration & dosage, Hemoglobins metabolism, Liver pathology, Liver Neoplasms chemically induced, Liver Neoplasms pathology, Male, Oxidative Stress drug effects, Rats, Rats, Inbred F344, Resins, Plant administration & dosage, Sex Factors, Toxicity Tests, Chronic methods, Toxicity Tests, Subacute methods, DNA Damage drug effects, Food Additives toxicity, Liver drug effects, Resins, Plant toxicity
- Abstract
Dammar resin is a natural food additive and flavoring substance present in many foods and drinks. The present study evaluates the chronic toxicity and carcinogenicity of dietary dammar resin in F344 rats. Dietary concentrations in the 52-week chronic toxicity study were 0, 0.03, 0.125, 0.5, or 2%. The major treatment-related deleterious effects were body weight suppression, increased relative liver weight, and low hemoglobin levels in males and females. Foci of cellular alteration in the liver were observed in the male 2% group, but not in any other group. The no-observed-adverse-effect level for chronic toxicity was 0.125% for males (200.4 mg/kg b.w./day) and females (241.9 mg/kg b.w./day). Dietary concentrations in the 104-week carcinogenicity study were 0, 0.03, 0.5, or 2%. Dammar resin induced hemorrhagic diathesis in males and females, possibly via the inhibition of extrinsic and intrinsic coagulation pathways. Incidences of hepatocellular adenomas and carcinomas were significantly increased in the male 2% group, but not in any other group. In the 4-week subacute toxicity study, the livers of male rat-fed diet-containing 2% dammar resin had increased levels of protein oxidation and increased the expression of two anti-apoptotic and seven cytochrome P450 (CYP) genes. There was also an increased tendency of oxidative DNA damage. These findings demonstrate that dammar resin is hepatocarcinogenic in male F344 rats and underlines the roles of inhibition of apoptosis, induction of CYP enzymes, and oxidative stress in dammar resin-induced hepatocarcinogenesis.
- Published
- 2018
- Full Text
- View/download PDF
46. Polymer-brush-afforded SPIO Nanoparticles Show a Unique Biodistribution and MR Imaging Contrast in Mouse Organs.
- Author
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Chen T, Mori Y, Inui-Yamamoto C, Komai Y, Tago Y, Yoshida S, Takabatake Y, Isaka Y, Ohno K, and Yoshioka Y
- Subjects
- Animals, Injections, Intravenous, Male, Mice, Mice, Inbred C57BL, Tissue Distribution, Contrast Media administration & dosage, Ferric Compounds administration & dosage, Kidney diagnostic imaging, Liver diagnostic imaging, Magnetic Resonance Imaging methods, Nanoparticles administration & dosage, Polymers administration & dosage
- Abstract
Introduction: To investigate the biodistribution and retention properties of the new super paramagnetic iron oxide (new SPIO: mean hydrodynamic diameter, 100 nm) nanoparticles, which have concentrated polymer brushes in the outer shell and are difficult for phagocytes to absorb, and to compare the new SPIO with clinically approved SPIO (Resovist: mean hydrodynamic diameter, 57 nm)., Materials and Methods: 16 male C57BL/6N mice were divided in two groups according to the administered SPIO (n = 8 for each group; intravenous injection does, 0.1 ml). In vivo magnetic resonance imaging (MRI) was performed before and one hour, one day, one week and four weeks after SPIO administration by two dimensional-the fast low angle shot (2D-FLASH) sequence at 11.7T. Ex vivo high-resolution images of fixed organs were also obtained by (2D-FLASH). After the ex vivo MRI, organs were sectioned and evaluated histologically to confirm the biodistribution of each particle precisely., Results: The new SPIO was taken up in small amounts by liver Kupffer cells and showed a unique in vivo MRI contrast pattern in the kidneys, where the signal intensity decreased substantially in the boundaries between cortex and outer medulla and between outer and inner medulla. We found many round dark spots in the cortex by ex vivo MRI in both groups. Resovist could be detected almost in the cortex. The shapes of the dark spots were similar to those observed in the new SPIO group. Transmission electron microscopy revealed that Resovist and the new SPIO accumulated in different cells of glomeruli, that is, endothelial and mesangial cells, respectively., Conclusion: The new SPIO was taken up in small amounts by liver tissue and showed a unique MRI contrast pattern in the kidney. The SPIO were found in the mesangial cells of renal corpuscles. Our results indicate that the new SPIO may be potentially be used as a new contrast agent for evaluation of kidney function as well as immunune function.
- Published
- 2017
- Full Text
- View/download PDF
47. Pueraria mirifica Exerts Estrogenic Effects in the Mammary Gland and Uterus and Promotes Mammary Carcinogenesis in Donryu Rats.
- Author
-
Kakehashi A, Yoshida M, Tago Y, Ishii N, Okuno T, Gi M, and Wanibuchi H
- Subjects
- 9,10-Dimethyl-1,2-benzanthracene pharmacology, Animals, Female, Mammary Glands, Animal pathology, Mammary Neoplasms, Animal chemically induced, Mammary Neoplasms, Animal pathology, Methylnitronitrosoguanidine analogs & derivatives, Methylnitronitrosoguanidine pharmacology, Rats, Uterus pathology, Carcinogens pharmacology, Estrogens pharmacology, Mammary Glands, Animal drug effects, Phytoestrogens pharmacology, Plant Preparations pharmacology, Pueraria, Uterus drug effects
- Abstract
Pueraria mirifica (PM), a plant whose dried and powdered tuberous roots are now widely used in rejuvenating preparations to promote youthfulness in both men and women, may have major estrogenic influence. In this study, we investigated modifying effects of PM at various doses on mammary and endometrial carcinogenesis in female Donryu rats. Firstly, PM administered to ovariectomized animals at doses of 0.03%, 0.3%, and 3% in a phytoestrogen-low diet for 2 weeks caused significant increase in uterus weight. Secondly, a 4 week PM application to non-operated rats at a dose of 3% after 7,12-dimethylbenz[a]anthracene (DMBA) initiation resulted in significant elevation of cell proliferation in the mammary glands. In a third experiment, postpubertal administration of 0.3% (200 mg/kg body weight (b.w.)/day) PM to 5-week-old non-operated animals for 36 weeks following initiation of mammary and endometrial carcinogenesis with DMBA and N -ethyl- N '-nitro- N -nitrosoguanidine (ENNG), respectively, resulted in significant increase of mammary adenocarcinoma incidence. A significant increase of endometrial atypical hyperplasia multiplicity was also observed. Furthermore, PM at doses of 0.3%, and more pronouncedly, at 1% induced dilatation, hemorrhage and inflammation of the uterine wall. In conclusion, postpubertal long-term PM administration to Donryu rats exerts estrogenic effects in the mammary gland and uterus, and at a dose of 200 mg/kg b.w./day was found to promote mammary carcinogenesis initiated by DMBA., Competing Interests: The authors declare no conflict of interest.
- Published
- 2016
- Full Text
- View/download PDF
48. Role of deltaNp63(pos)CD44v(pos) cells in the development of N-nitroso-tris-chloroethylurea-induced peripheral-type mouse lung squamous cell carcinomas.
- Author
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Yamano S, Gi M, Tago Y, Doi K, Okada S, Hirayama Y, Tachibana H, Ishii N, Fujioka M, Tatsumi K, and Wanibuchi H
- Subjects
- Animals, Carcinogens toxicity, Carcinoma, Squamous Cell immunology, Carmustine analogs & derivatives, Carmustine toxicity, Disease Models, Animal, Disease Progression, Female, Hyaluronan Receptors biosynthesis, Hyaluronan Receptors immunology, Immune Tolerance immunology, Immunohistochemistry, Lung Neoplasms immunology, Macrophages pathology, Mice, Phosphoproteins biosynthesis, Phosphoproteins immunology, Trans-Activators biosynthesis, Trans-Activators immunology, Tumor Escape immunology, Carcinoma, Squamous Cell pathology, Lung Neoplasms pathology, Neoplastic Stem Cells pathology, Precancerous Conditions pathology, Tumor Microenvironment immunology
- Abstract
The role of cells expressing stem cell markers deltaNp63 and CD44v has not yet been elucidated in peripheral-type lung squamous cell carcinoma (pLSCC) carcinogenesis. Female A/J mice were painted topically with N-nitroso-tris-chloroethylurea (NTCU) for induction of pLSCC, and the histopathological and molecular characteristics of NTCU-induced lung lesions were examined. Histopathologically, we found atypical bronchiolar hyperplasia, squamous metaplasia, squamous dysplasia, and pLSCCs in the treated mice. Furthermore, we identified deltaNp63(pos)CD44v(pos)CK5/6(pos)CC10(pos) clara cells as key constituents of early precancerous atypical bronchiolar hyperplasia. In addition, deltaNp63(pos)CD44v(pos) cells existed throughout the atypical bronchiolar hyperplasias, squamous metaplasias, squamous dysplasias, and pLSCCs. Overall, our findings suggest that NTCU induces pLSCC through an atypical bronchiolar hyperplasia-metaplasia-dysplasia-SCC sequence in mouse lung bronchioles. Notably, Ki67-positive deltaNp63(pos)CD44v(pos) cancer cells, cancer cells overexpressing phosphorylated epidermal growth factor receptor and signal transducer and activator of transcription 3, and tumor-associated macrophages were all present in far greater numbers in the peripheral area of the pLSCCs compared with the central area. These findings suggest that deltaNp63(pos)CD44v(pos) clara cells in mouse lung bronchioles might be the origin of the NTCU-induced pLSCCs. Our findings also suggest that tumor-associated macrophages may contribute to creating a tumor microenvironment in the peripheral area of pLSCCs that allows deltaNp63(pos)CD44v(pos) cancer cell expansion through activation of epidermal growth factor receptor signaling, and that exerts an immunosuppressive effect through activation of signal transducer and activator of transcription 3 signaling., (© 2015 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)
- Published
- 2016
- Full Text
- View/download PDF
49. From cartoon to real time MRI: in vivo monitoring of phagocyte migration in mouse brain.
- Author
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Mori Y, Chen T, Fujisawa T, Kobashi S, Ohno K, Yoshida S, Tago Y, Komai Y, Hata Y, and Yoshioka Y
- Subjects
- Animals, Brain drug effects, Brain immunology, Cell Movement drug effects, Cell Tracking instrumentation, Contrast Media administration & dosage, Ferric Compounds administration & dosage, Genes, Reporter, Green Fluorescent Proteins metabolism, Inflammation chemically induced, Inflammation diagnosis, Inflammation immunology, Inflammation pathology, Injections, Intraperitoneal, Injections, Intravenous, Lipopolysaccharides toxicity, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Microglia drug effects, Microglia immunology, Microglia pathology, Phagocytes drug effects, Phagocytes immunology, Single-Cell Analysis instrumentation, Time-Lapse Imaging, Video Recording, Brain pathology, Cell Tracking methods, Magnetic Resonance Imaging methods, Phagocytes pathology, Single-Cell Analysis methods
- Abstract
Recent studies have demonstrated that immune cells play an important role in the pathogenesis of many neurological conditions. Immune cells constantly survey the brain microvasculature for irregularities in levels of factors that signal homeostasis. Immune responses are initiated when necessary, resulting in mobilisation of the microglial cells resident in the central nervous system (CNS) and/or of infiltrating peripheral cells. However, little is known about the kinetics of immune cells in healthy and diseased CNS, because it is difficult to perform long-term visualisation of cell motility in live tissue with minimal invasion. Here, we describe highly sensitive in vivo MRI techniques for sequential monitoring of cell migration in the CNS at the single-cell level. We show that MRI combined with intravenous administration of super-paramagnetic particles of iron oxide (SPIO) can be used to monitor the transmigration of peripheral phagocytes into healthy or LPS-treated mouse brains. We also demonstrate dynamic cell migration in live animal brains with time-lapse MRI videos. Time-lapse MRI was used to visualise and track cells with low motility in a control mouse brain. High-sensitivity MRI cell tracking using SPIO offers new insights into immune cell kinetics in the brain and the mechanisms of CNS homeostasis.
- Published
- 2014
- Full Text
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50. Genotoxicity and subacute toxicity studies of a new astaxanthin-containing Phaffia rhodozyma extract.
- Author
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Tago Y, Fujii T, Wada J, Kato M, Wei M, Wanibuchi H, and Kitano M
- Subjects
- Administration, Oral, Animals, Dose-Response Relationship, Drug, Female, Humans, Male, Mice, Mice, Inbred ICR, Micronucleus Tests, Mutagenicity Tests, Mutation drug effects, No-Observed-Adverse-Effect Level, Rats, Rats, Sprague-Dawley, Salmonella typhimurium drug effects, Salmonella typhimurium genetics, Xanthophylls administration & dosage, Xanthophylls isolation & purification, Xanthophylls toxicity, Basidiomycota chemistry
- Abstract
Experimental and clinical studies demonstrate that astaxanthin (AXN), a xanthophyll carotenoid, has protective effects against oxidative damage. Because most of these studies assessed AXN derived from Haematococcus pluvialis that were cultivated at industrial scales, few studies have examined the toxicity of AXN derived from Phaffia rhodozyma. To evaluate the safety of astaxanthin-containing P. rhodozymaextract (AXN-PRE), genotoxicity was assessed in bacterial reverse mutation test and mouse bone marrow micronucleus test, and general toxicity was assessed in 4-week repeated oral toxicity study in rats. AXN-PRE did not induce reverse mutations in the Salmonella typhimurium strains TA98 or TA100 at concentrations of 5,000 µg/plate with or without S9 mix, and no chromosome damage was observed at a dose of 2,000 mg/kg in mouse micronucleus test. In the subacute toxicity study, male and female Sprague-Dawley rats were given AXN-PRE at doses of 0, 500, and 1,000 mg/kg by gavage for 4 weeks. Body weights, urinalysis, hematology, serum biochemistry, organ weights, or histopathological lesions indicated no distinct toxicity. In conclusion, AXN-PRE had no effect in bacterial reverse mutation test and mouse bone marrow micronucleus test. The no-observed-adverse-effect level for AXN-PRE in 4-week repeated oral toxicity study in rats was determined to be greater than 1,000 mg/kg (corresponding to dose of 50 mg/kg AXN) regardless of gender.
- Published
- 2014
- Full Text
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