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Search Results: 1 - 10 of 6693 matches for " Hiroshi Yamada "
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A New Metal Tag for Highly Selective and Sensitive Analyses of Amino Acids and Dipeptides by HPLC/ICP-MS  [PDF]
Daigo Iwahata, Kazuki Nakamura, Rie Yamada, Hiroshi Miyano, Naoyuki Yamada
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2013, DOI: 10.4236/jasmi.2013.32010
Abstract:

We have developed a novel metal tag, bis(ethylenediamine)-4'-methyl-4-carboxybipyridine-ruthenium N-succinimidyl ester (ECRS) for sensitive analysis of amino acids using high performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS). ECRS is a functional reagent, containing an ester group at one end that can be activated to bind to amino group and a chelated ruthenium at the other. The activated ester was reacted briefly with amino groups under weakly alkaline conditions. The ruthenium was detected sensitively by ICP-MS. ECRS was reacted with 17 proteinogenic amino acids in borate buffer. The derivatives were separated by reversed phase HPLC and identified by quadrupole-based ICP-MS. ECRS was suitable for speciation; low molecular weight compounds containing amino groups. We have thus established a quantitative analytical method for amino acids and dipeptides. The detection limits of branched amino acids (signal-to-noise ratio of 3) were 1.5 nmol·L-1 in the standard solution (100 amol per injection).

Total Recovery of Sinker Weights from Lead-Core Fishing Nets  [PDF]
Masafumi Tateda, Hiroshi Yamada, Youngchul Kim
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.54038
Abstract:

The adverse effects of lead poisoning have long been of environmental concern. A large number of research papers have reported many routes of lead poisoning, of which lead sinkers used in fishing require urgent attention. Lead sinkers that are abandoned or scattered from individual fishing gear are notorious for environmental pollution and have been reported in many papers; moreover, lead-core “sinker rope” is used in fishery nets. This paper discusses the latter, which generally has limited public awareness. Preliminary work and field studies were conducted to develop a system for total treatment of lead from fishing nets with lead-cored sinker ropes, in order to prevent environmental pollution and conserve natural resources. Lead sinkers in fishing nets were successfully removed, yielding high-quality lead suitable for commercial purposes. Appropriate management of fishing nets is crucial for environmental protection and resource conservation.

Joint Coordination Organizes to Form the Task-Dependent Trajectory of the Body Center of Mass  [PDF]
Yoichiro Sato, Hiroshi Nagasaki, Norimasa Yamada
Journal of Behavioral and Brain Science (JBBS) , 2016, DOI: 10.4236/jbbs.2016.61001
Abstract: As the central nervous system controls whole-body motion, which involves multi-joint movement, certain problems with regard to the number of variables controlled by the central nervous system arise (i.e., the “degree of freedom problem”). The central nervous system solves these problems not by controlling joint movements, but rather by controlling only the task-dependent center of mass (COM) position of the whole body. Although uncontrolled joint movement should be organized in a coordinate manner to form the task-dependent COM position, it is unclear what kind of law joint coordination is organized by. Hence, in the present study, we aim to clarify the shape of joint coordination by elucidating the mutual relationship between the COM trajectory and joint movement during whole-body motion. Downward squatting motions with five trunk angles are recorded by using a 3-D motion analysis system in 8 healthy males. The COM trajectory shows a task-dependent path in all trunk conditions. The shank angle decreases with an increase in the trunk angle to produce the task-dependent COM trajectory, whereas the thigh showsd a constant angle. These findings demonstrate that the COM trajectory is constrained by biomechanical dynamics and minimum muscle torques, and that the joints are organized into a lawful coordinative structure to form the COM trajectory.
Influence of container structures and content solutions on dispensing time of ophthalmic solutions
Keiji Yoshikawa, Hiroshi Yamada
Clinical Ophthalmology , 2010, DOI: http://dx.doi.org/10.2147/OPTH.S10804
Abstract: fluence of container structures and content solutions on dispensing time of ophthalmic solutions Original Research (3009) Total Article Views Authors: Keiji Yoshikawa, Hiroshi Yamada Published Date May 2010 Volume 2010:4 Pages 481 - 486 DOI: http://dx.doi.org/10.2147/OPTH.S10804 Keiji Yoshikawa1, Hiroshi Yamada2 1Yoshikawa Eye Clinic, Tokyo, Japan; 2Santen Pharmaceutical Co., Ltd., Osaka, Japan Purpose: To investigate the influence of container structures and content solutions on the time of dispensing from eye dropper bottles. Methods: Eye dropper bottle models, solution models (filtrate water/surfactant solution) and a dispensing time measuring apparatus were prepared to measure the dispensing time. Results: With filtrate water and pressure thrust load of 0.3 MPa, the dispensing time significantly increased from 1.1 ± 0.5 seconds to 4.6 ± 1.1 seconds depending on the decrease of inner aperture diameters from 0.4 mm to 0.2 mm (P < 0.0001). When using the bottle models with inner aperture diameters of 0.4 mm or larger, the dispensing time became constant. The dispensing time using surfactant solution showed the same tendency as above. When pressure thrust load was large (0.07 MPa), the solution flew out continuously with inner aperture diameters of 0.4 mm or larger and the dispensing time could not be measured. The inner aperture diameter most strongly explained the variation of the dispensing time in both the content solutions in the multiple linear regression analysis (filtrate water: 46%, R2 = 0.462, surfactant solution: 56%, R2 = 0.563). Conclusions: Among content solutions and container structures, the dispensing time was mostly influenced by the diameter of the inner aperture of bottles.
Influence of container structures and content solutions on dispensing time of ophthalmic solutions
Keiji Yoshikawa,Hiroshi Yamada
Clinical Ophthalmology , 2010,
Abstract: Keiji Yoshikawa1, Hiroshi Yamada21Yoshikawa Eye Clinic, Tokyo, Japan; 2Santen Pharmaceutical Co., Ltd., Osaka, JapanPurpose: To investigate the influence of container structures and content solutions on the time of dispensing from eye dropper bottles.Methods: Eye dropper bottle models, solution models (filtrate water/surfactant solution) and a dispensing time measuring apparatus were prepared to measure the dispensing time.Results: With filtrate water and pressure thrust load of 0.3 MPa, the dispensing time significantly increased from 1.1 ± 0.5 seconds to 4.6 ± 1.1 seconds depending on the decrease of inner aperture diameters from 0.4 mm to 0.2 mm (P < 0.0001). When using the bottle models with inner aperture diameters of 0.4 mm or larger, the dispensing time became constant. The dispensing time using surfactant solution showed the same tendency as above. When pressure thrust load was large (0.07 MPa), the solution flew out continuously with inner aperture diameters of 0.4 mm or larger and the dispensing time could not be measured. The inner aperture diameter most strongly explained the variation of the dispensing time in both the content solutions in the multiple linear regression analysis (filtrate water: 46%, R2 = 0.462, surfactant solution: 56%, R2 = 0.563).Conclusions: Among content solutions and container structures, the dispensing time was mostly influenced by the diameter of the inner aperture of bottles.Keywords: dispensing time, model eye dropper bottle, model ophthalmic solution, nozzle internal space volume, nozzle inner aperture diameter
Magnetic Susceptibility of the Orbitally Degenerate (J= 5/2) Periodic Anderson Model - Analysis on the Basis of the Fermi Liquid Theory
Hiroshi Kontani,Kosaku Yamada
Physics , 1996, DOI: 10.1143/JPSJ.65.172
Abstract: In the orbitally degenerate ($J=5/2$) Periodic Anderson Model, the magnetic susceptibility is composed of both the Pauli term and the Van Vleck term, as is well known. The former is strongly enhanced by the strong correlation between $f$-electrons. But, for the latter, the influence of the strong correlation has been obscure for years. In this paper we give the solution of the longstanding problem. With the aid of the $d=\infty$ approximation, we study this problem on the basis of the Fermi liquid theory with degenerate orbitals, taking account of all the vertex corrections in a consistent way. As a result, we obtain the simple expression for the magnetic susceptibility, and show unambiguously that the Van Vleck term is also highly enhanced} in the strong correlation regime. This fact explains naturally the enhanced magnetic susceptibility observed in many insulating systems (i.e., Kondo insulator). Moreover, we show that the Wilson ratio takes a value around 1 in the metallic system, in good agreement with experiments.
Electronic State and Magnetic Susceptibility in Orbitally Degenerate (J=5/2) Periodic Anderson Model
Hiroshi Kontani,Kosaku Yamada
Physics , 1997, DOI: 10.1143/JPSJ.66.2232
Abstract: Magnetic susceptibility in a heavy fermion systemis composed of the Pauli term (\chi_P) and the Van-Vleck term (\chi_V). The latter comes from the interband excitation, where f-orbital degeneracy is essential. In this work, we study \chi_P and \chi_V in the orbitally degenerate (J=5/2) periodic Anderson model for both the metallic and insulating cases. The effect of the correlation between f-electrons is investigated using the self-consistent second-order perturbation theory. The main results are as follows. (i) Sixfold degenerate model: both \chi_P and \chi_V are enhanced by a factor of 1/z (z is the renormalization constant). (ii) Nondegenerate model: only \chi_P is enhanced by 1/z. Thus, orbital degeneracy is indispensable for enhancement of \chi_V. Moreover, orbital degeneracy reduces the Wilson ratio and stabilizes a nonmagnetic Fermi liquid state.
Neutrino - nucleon reaction rates in the supernova core in the relativistic random phase approximation
Shoichi Yamada,Hiroshi Toki
Physics , 1999, DOI: 10.1103/PhysRevC.61.015803
Abstract: In view of the application to supernova simulations, we calculate neutrino reaction rates with nucleons via the neutral and charged currents in the supernova core in the relativistic random phase approximation (RPA) and study their effects on the opacity of the supernova core. The formulation is based on the Lagrangian employed in the calculation of nuclear equation of state (EOS) in the relativistic mean field theory (RMF). The nonlinear meson terms are treated appropriately so that the consistency of the density correlation derived in RPA with the thermodynamic derivative obtained from EOS by RMF is satisfied in the static and long wave length limit. We employ pion and rho meson exchange interactions together with the phenomenological Landau-Migdal parameters for the isospin-dependent nuclear interactions. We find that both the charged and neutral current reaction rates are suppressed from the standard Bruenn's approximate formula considerably in the high density regime. In the low density regime, on the other hand, the vector current contribution to the neutrino-nucleon scattering rate is enhanced in the vicinity of the boundary of the liquid-gas phase transition, while the other contributions are moderately suppressed there also. In the high temperature regime or in the regime where electrons have a large chemical potential, the latter of which is important only for the electron capture process and its inverse process, the recoil of nucleons cannot be neglected and further reduces the reaction rates with respect to the standard approximate formula which discards any energy transfer in the processes. These issues could have a great impact on the neutrino heating mechanism of collapse-driven supernovae.
From Kondo Effect to Fermi Liquid
Hiroshi Kontani,Kosaku Yamada
Physics , 2004, DOI: 10.1143/JPSJ.74.155
Abstract: The Kondo effect has been playing an important role in strongly correlated electon systems. The important point is that the magnetic impurity in metals is a typical example of the Fermi liquid. In the system the local spin is conserved in the ground state and continuity with respect to Coulomb repulsion $U$ is satisfied. This nature is satisfied also in the periodic systems as far as the systems remain as the Fermi liquid. This property of the Fermi liquid is essential to understand the cuprate high-Tc superconductors (HTSC). On the basis of the Fermi liquid theory we develop the transport theory such as the resistivity and the Hall coefficient in strongly correlated electron systems, such as HTSC, organic metals and heavy Fermion systems. The significant role of the vertex corrections for total charge- and heat-currents on the transport phenomena is explained. By taking the effect of the current vertex corrections into account, various typical non-Fermi-liquid-like transport phenomena in systems with strong magnetic and/or superconducting flucutations are explained within the Fermi liquid theory.
Research on the Deformation of Turbine Blades at Machining  [PDF]
Masu Yamada, Keiji Sonoya, Takahito Sobayashi, Hiroshi Satoh
Energy and Power Engineering (EPE) , 2016, DOI: 10.4236/epe.2016.81001
Abstract: Along with the recent expansion of demand for electricity, the production of steam turbine blades has increased, and various materials forged of 12Cr ferritic heat-resistant types of steel have become widely used for this purpose. Although this material seems to be an excellent choice as heat-resistant steel, it requires a post-correction process for deformation after machining and thus lowers productivity. Therefore, we started basic experimental research, and through a series of tests, we found that 12Cr steel is a sticky material; the residual stresses after machining concentrate in the vicinity of the surface; and this influences the deformation of blades.
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