T. Kato

Gifu University Hospital, Gihu, Gifu, Japan

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Publications (315)631.41 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: Background and study aims: The aim of the current study was to assess the detection rate of the right adrenal gland and the diagnostic ability of endoscopic ultrasound (EUS) and fine-needle aspiration (FNA) for the diagnosis of adrenal metastasis in potentially resectable lung cancer.Patients and methods: This retrospective cohort study included a consecutive series of 150 patients undergoing EUS/EUS - FNA for staging of lung cancer. The detection rate of the right adrenal gland by EUS and the diagnostic accuracies of computed tomography (CT), positron emission tomography-CT (PET-CT), and EUS/EUS - FNA for the diagnosis of adrenal metastasis were evaluated.Results: The right adrenal gland was visualized by EUS in 131 patients (87.3 %); the left adrenal gland was visualized in all patients. Findings suggestive of metastasis in either one of the adrenal glands or in both were observed in 6 patients (4.0 %) by CT, in 5 patients (3.3 %) by PET-CT, and in 11 patients (7.3 %) by EUS. EUS - FNA was performed simultaneously in the 11 patients, and in 4 patients the diagnosis of metastasis was established. The accuracy for the diagnosis of adrenal metastasis was 100 % for EUS/EUS - FNA, 96.0 % for CT, and 97.0 % for PET-CT (P = 0.1146). Conclusions: As well as the left adrenal gland, the right adrenal gland was also usually visible by EUS. EUS/EUS - FNA provided an accurate diagnosis of adrenal metastasis, although the prevalence of adrenal metastasis was relatively low in these patients with potentially resectable lung cancer.
    Endoscopy 01/2013; · 5.74 Impact Factor
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    ABSTRACT: We propose a method to evaluate transport AC losses in Bi-2223 superconducting coils by integrating the local external-field losses of the stacked taped wires over the coil's windings. We measured the transport AC losses of a 16 double-pancake coil of twisted Bi-2223 Ag-sheathed tapes, in the frequency range from 0.1 to 10 Hz at liquid nitrogen temperature. We also measured the external-field losses of short specimens of 6-stack Bi-2223 wires both in perpendicular and parallel field configurations through a saddle-shaped pickup coil method. The external losses are mainly due to hysteresis losses in the superconducting filaments and coupling losses among the filaments. The local external-field loss in the test coil is approximately calculated as the sum of perpendicular- and parallel-field losses of the short specimen. In the calculation, geometrical effects because of the neighboring turns in the coil are also considered, in addition to the magnitude and direction distributions of the local magnetic field. We compared the numerically evaluated external-field losses to the measured transport AC losses, and discussed the applicability of the proposed method.
    IEEE Transactions on Applied Superconductivity 01/2013; 23(3):4700804-4700804. · 1.20 Impact Factor
  • T. Kato, K. Kawai, Y. Suzuoki
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    ABSTRACT: An electric power system containing high penetration photovoltaic power generation system (PVS) should employ a highly accurate day-ahead forecast method of aggregated power output of PVS in the generation scheduling so as to realize the economic load dispatching. Considering the load-following capability of utility generators, however, small forecast error is not so influential, while large forecast error should be avoided. By using a simplified unit commitment model, this study evaluates the forecast accuracy of aggregated PVS power output by means of the amount of shortage or surplus of power supply in the electric power system. As a result, the shortage occurs occasionally, requiring the increase in the operating reserve. The surplus occasionally occurs in spring even without the forecast error. Avoiding the large forecast error contributes to the decrease in the operating-reserve of utility generators as well as the suppressed PVS power output, even though the average forecast accuracy is not improved so much.
    Power and Energy Society General Meeting (PES), 2013 IEEE; 01/2013
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    ABSTRACT: High penetration photovoltaic power generation system (PVS) would cause some negative impacts on the stable operation of electric power system. On the other hand, when PVSs are widely dispersed, the total power output fluctuation would be smoothed. In order to evaluate the spatial average insolation fluctuation by using the insolation data observed at the limited number of points, we have developed the method to take the smoothing-effect around the observation point into account. Then, by using the insolation data observed at 61 points in the Chubu region in Japan, this study statistically evaluated the long-cycle fluctuation of the spatial average insolation. As the results, the absolute value of the maximum fluctuation width (MFW) of ensemble average insolation calculated with 120 min width window ranges mainly between 200 and 300 W/m2, while it is larger than 400 W/m2 in 6 days (1.7%). The results suggest that the reliable forecast method of spatial average insolation is needed to mitigate the impact of total power output change due to the insolation change of 400 W/m2 in 120 min.
    Power and Energy Society General Meeting, 2012 IEEE; 01/2012
  • T. Kato, Y. Suzuoki
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    ABSTRACT: The high penetration photovoltaic power generation systems (PVS) may cause the voltage rise of a power distribution system. As one of the measures, we focus on the daytime operation of heat pump water heater (HPWH). This study introduces the brief idea for scheduling the daytime operation so that the total electricity demand change of a number of HP follows the insolation change in a day. Then, this study demonstrates the effect of daytime operation using the electricity and hot-water demand observed in 10 households for a year. As the result, when the daytime operation is applied to HPWH in a household with PVS, the voltage rise can be mitigated without causing the under voltage condition due to the unnecessary daytime operation.
    Engineering and Technology (S-CET), 2012 Spring Congress on; 01/2012
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    ABSTRACT: We investigated the influence of AC voltage prestressing on the electrical-tree inception voltage in LDPE. When AC voltage prestress was not imposed, the impulse-tree inception voltage increased with the size of water tree due to the electrical field relaxation. On the other hand, when AC voltage prestress was imposed, the impulse-tree inception voltage did not change with the water-tree size and was lower than that without AC voltage prestressing. The FTIR absorption measurements showed several absorptions between 650 and 1500 cm-1, which did not exist in the sample without AC voltage prestressing. Besides, the TEM observation revealed that the AC voltage prestressing increased the density and size of micro voids and some of them were aligned in the direction of applied electric field. These results suggest that AC voltage prestressing causes structural change in the water tree and enhances material degradation, leading to lower tree-inception voltage.
    Electrical Insulation and Dielectric Phenomena (CEIDP), 2012 Annual Report Conference on; 01/2012
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    ABSTRACT: Changes in density and viscosity due to the post-spinel transformation have important effects on mantle flow across the 660-km seismic discontinuity and the style of mantle convection. In the present study, we have determined forward and backward reaction kinetics of the post-spinel transformation and examined evolution of transformation microstructures. Based on the experimental results, we suggest that the post-spinel transformation is delayed in both up- and down-going mantle flows due to the kinetic effects, which produces detectable topography of the 660-km discontinuity. We also discuss viscosity reduction in down-going material across the 660-km discontinuity due to the grain-size reduction. The transformation kinetics was investigated by time-resolved X-ray diffraction measurements in BL04B1 at SPring-8. In case of the forward reaction, the annealed polycrystalline Mg2SiO4 ringwoodite (Rw) was transformed to MgSiO3 perovskite (Pv) and MgO periclase (Pc). On the other hand, the annealed aggregate of Pv+Pc was transformed to Rw in case of the backward reaction. We analyzed the kinetic data obtained at various P-T conditions, and estimated nucleation and growth kinetics in each reaction. The rate of the forward reaction is much faster than that of the backward reaction mainly due to different growth mechanisms. Experimental results suggest that nucleation-controlled post-spinel transformation is dominant both in cold down-going and hot up-going flows across the 660-km discontinuity, in which the growth rate is fast enough compared to the flow speed but nucleation cannot occur resulting in the delay of the transformation. This inhibits the transfer of material across the discontinuity. We also suggest that the seismic discontinuity topography can be produced when material crosses the boundary. The magnitude of the topography, which corresponds to the overpressure needed for the nucleation, is estimated to be at least 15-20 km depths (0.6-0.8 GPa) in case of the forward reaction. That for the backward reaction has not quantitatively determined yet, but probably larger. Thus, it may be possible to detect the vertical flow across the upper and lower mantle boundary from the discontinuity topography. Weakening of slab materials in the lower mantle is controlled by grain-size evolution, which is very important to understand patterns of mantle convection. Microstructural observations revealed that the forward reaction occurs by grain-boundary nucleation and growth of the post-spinel eutectoid colony consisting of fine lamellae. The size of the colony and the lamellar spacing are rather different, more than 10 micron and less than 1 micron at the overpressure of about 1 GPa, respectively, and both decrease with overpressures. Preliminary optical microscopic observations suggest that each colony of fine lamellae behaves like a single crystal. The slab weakening has been suggested based on the presence of fine lamellae, however it may not be so simple when considering the larger size of single crystal-like eutectoid colony.
    AGU Fall Meeting Abstracts. 12/2011;
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    ABSTRACT: Phase transformations of minerals have an important role on the rheology of earth's crust and mantle. Flow properties and the dominant mechanism of deformation are possibly affected through changes of the crystal structure, grain size and polycrystalline texture during the transformation. In this study, we have carried out in-situ X-ray diffraction experiments on the high-pressure decomposition reaction from albite, one end member of plagioclase, into jadeite and quartz under uniaxial differential stress. High-pressure deformation experiments were conducted using multi-anvil type deformation apparatus D-CAP 700 installed at the NE-7 beamline of PF-AR, KEK. The synthesized polycrystalline albite was annealed at the P-T conditions near the equilibrium phase boundary of albite decomposition. Then, the sample was deformed with the constant strain rates of 0.3-6.1×10-5/s at 1-4 GPa and 673-1073 K. Confining pressure increased during the deformation. The plastic deformation and high-pressure transformation processes were simultaneously observed by time-resolved two-dimensional X-ray diffraction (2DXRD) measurements using monochromatic X-ray (energy 50 keV) and imaging plate (IP). 2DXRD patterns were used to obtain the transformed fraction and the differential stress of the sample that was estimated from the distortion of the Debye ring (azimuthal angle-dependence of d-values) on IP. Plastic strain of the sample was measured from the X-ray radiography image. Deformation mechanism of polycrystalline albite was investigated from the results of 7 samples deformed at about 2.5 GPa and 873-1073K. Constant flow stress of albite was obtained after 5 percent axial strain. The stress exponent n was estimated to be 2.3 from the relationships of the steady-state flow stress and strain rate. The n-value and the elongated shape of albite grains suggest that the dominant deformation mechanism is dislocation creep. The six samples decomposed into jadeite and quartz during deformation experiments at 873-1073K. The decomposition started when overpressure from the phase boundary reached 0.4-1.4 GPa. FE-SEM observations of recovered samples revealed that the high-pressure phases nucleate at grain boundaries of parental albite and form colonies having a eutectoid structure. The eutectoid colonies are connected each other after about 50 % transformation. These changes in transformation textures affect the flow strength of each phase significantly. The flow stress of albite did not reach constant but increased with the transformed fraction, suggesting that strain hardening occurred in the parental phase during the transformation. On the other hand, the flow stress of newly formed jadeite rapidly dropped by one order of magnitude when the transformed fraction reached about 80 %. We will discuss about the relationship between the flow strength and the microstructural changes due to the transformation.
    AGU Fall Meeting Abstracts. 12/2011;
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    ABSTRACT: Recently, transesophageal endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been evaluated for mediastinal nodal staging (N staging) of lung cancer, as this technique is less invasive than mediastinoscopy and possibly more accurate than 18F-fluorodeoxyglucose positron emission tomography with computed tomography (PET-CT). However, EUS-FNA does not provide access to pretracheal and hilar lymph nodes. More recently, endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been introduced as a novel technique for accessing pretracheal and hilar lymph nodes. Although the combined endoscopic approach of EUS-FNA and EBUS-TBNA is presumably more accurate than PET-CT, only a few reports have quantitatively evaluated its diagnostic ability. Therefore, we prospectively assessed the diagnostic yield of this combined endoscopic approach for mediastinal N staging of lung cancer. A consecutive series of 120 patients with suspected resectable lung cancer on CT findings underwent PET-CT and combined EUS-FNA/EBUS-TBNA. The accuracy and other diagnostic indices of the combined approach in mediastinal N staging were compared with those of PET-CT. Among the enrolled patients, a final pathological N stage was established in 110 patients. The accuracy of the combined approach using EUS-FNA and EBUS-TBNA was significantly higher than that of PET-CT (90.0 % vs. 73.6 %; P < 0.0001). The sensitivity, specificity, and positive and negative predictive values were respectively 71.8 %, 100 %, 100 %, and 86.6 % for the combined approach vs. 47.4 %, 87.5 %, 66.7 %, and 75.9 % for PET-CT. The combined endoscopic approach using EUS-FNA and EBUS-TBNA provided excellent diagnostic performance. Therefore, this approach is strongly recommended before surgery or mediastinoscopy to avoid futile thoracotomy and surgical intervention.
    Endoscopy 12/2011; 43(12):1082-9. · 5.74 Impact Factor
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    ABSTRACT: A search for neutron-antineutron (n - nbar) oscillation, a process with |\DeltaB| = 2 that has been predicted by right-left (R-L) symmetric gauge theories, was undertaken using the 24.5\times10^33 neutron-yrs exposure of Super- Kamiokande I, in an analysis that included the significant sources of experimental uncertainties. No evidence for n - nbar oscillation was found, the lower limit of the lifetime for neutrons bound in ^16 O was determined to be 1.89 \times 10^32 yrs at the 90% confidence level (C.L.), and the corresponding limit for the oscillation time for free neutrons was calculated to be 2.44 \times 10^8 sec using a theoretical suppression factor of 1.0 \times 10^23 sec^-1.
    09/2011;
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    ABSTRACT: The improvement of critical current density properties of REBCO coated conductors for applications in superconducting power devices is desired. It is known that the critical current density J<sub>c</sub> of REBCO thin films made by the TFA-MOD method in a magnetic field is greatly improved by the introduction of BZO-nanoparticles of a non-superconducting phase as artificial pinning centers. In addition, the field angle anisotropy can also be reduced by isotropic flux pinning interactions of nanoparticles. However, a detailed report on the mechanism of flux pinning with a quantitative investigation in such coated conductors has not been given. In this study, the field angle dependence of the critical current density is measured for TFA-MOD-processed YGdBCO coated conductor with a superconducting layer of 0.65 μm thick, and the results are theoretically analysed to clarify the flux pinning mechanism.
    IEEE Transactions on Applied Superconductivity 07/2011; · 1.20 Impact Factor
  • 06/2011: pages 23 - 32; , ISBN: 9781118144121
  • T. Kato, T. Inoue, Y. Suzuoki
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    ABSTRACT: This study proposes a method to estimate the standard deviation (STD) of total power output fluctuation of high penetration photovoltaic power generation system (HP- PVS) dispersed in large area, so that the impact of HP-PVS on the load frequency control is discussed. First, by using the data of horizontal global insolation observed at 5 points in 25 km x 25 km area, the practical usefulness of STD is evaluated by comparing the STD with the maximum fluctuation width. Then, two key factors of the proposed model are discussed; the distance with which the insolation fluctuations at two points can be considered as independent, and the practical usefulness of the central limit theorem to estimate the STD of ensemble average fluctuation of insolation. Finally, assuming the geographical distribution of residential PVS, the STD of total power output fluctuation of HP-PVS dispersed in the service area of electric power utility is evaluated.
    01/2011;
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    ABSTRACT: BaZrO3 doped GdBa2Cu3O7−δ superconductor was prepared by pulsed layer deposition using a KrF excimer laser, which showed isotropic characteristics of critical current density, JC, for magnetic-field orientations, ∼ 4.0×109 A m−2 at 1.0 T. Microstructural and morphological characterization of resulting artificial pinning centers were conducted by transmission electron microscopy and electron tomography, which confirmed the presence of one-dimensional artificial pinning centers, BaZrO3 nanorods. Since there is noticeable anisotropy from GdBa2Cu3O7−δ superconductor without doping BaZrO3, the pinning observed for all magnetic-field orientations are due to the high density and high dispersion of these BaZrO3 nanorods with very wide angular distributions.
    Journal of Applied Physics 09/2010; 108(6):063901-063901-4. · 2.21 Impact Factor
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    ABSTRACT: In this study, we investigated the magnetization response of the polycrystalline magnetic garnet film for stress. The calculation suggests that the balance of the magnetic anisotropic energy under magnetic field is an essential factor to modulate the magnetization by stress. We fabricated the magnetophotonic crystal based voltage driven type magneto-optic spatial light modulator, and measured the magneto-optic response for stress. The experimental results had a good agreement with our calculation. In our results, the magnitude and linearity of the modulation by stress was depending on static bias field, stress, and magnetostriction constant. The obtained results implied that the calculation could estimate the device performance by deciding material composition and prepare stress inside garnet.
    Journal of Applied Physics 06/2010; · 2.21 Impact Factor
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    ABSTRACT: We prepared the reflection type magnetophotonic crystals (R-MPC) to enhance the magneto-optic property of magneto-optic spatial light phase modulator (MOSLM). Magnetophotonic crystals have a localized wavelength by using a defect layer in which the magneto-optic property can be increased tremendously. By the calculation, it was revealed clearly that Kerr rotation can be enhanced with increasing the repetition number (k) which is the number of dielectric layer. In this study, Dy <sub>1.0</sub> Bi <sub>1.5</sub> Y <sub>1.0</sub> Fe <sub>3.8</sub> Al <sub>1.2</sub> O <sub>12</sub> (DyBi:YIG) garnet material, of which Faraday rotation angle is about -3 deg /μ m , was utilized as a defect layer. At the designed wavelength of 532 nm and k =5 , SGGG /[ SiO <sub>2</sub>/ Ta <sub>2</sub> O <sub>5</sub>]<sub>2</sub>/ DyBi : YIG /[ SiO <sub>2</sub>/ Ta <sub>2</sub> O <sub>5</sub>]<sub> k </sub> structure fabricated with garnet thickness of 347.6 nm showed Kerr rotation angle of 26° and reflectivity of 0.2% which is coincident considerably with the results ( θ<sub> k </sub>=30° and R =0.59 % ) calculated by the matrix approach method. The fabricated R-MPC-MOSLM structure exhibited the magneto-optic property of about 25 times higher than single garnet film in consideration of the thickness of magneto-optic material.
    Journal of Applied Physics 06/2010; · 2.21 Impact Factor
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    ABSTRACT: Time-resolved two-dimensional X-ray diffraction method has been applied to observe kinetic properties of polycrystalline high-pressure ices in diamond anvil cell. The relationships between the number of diffraction spots and the number of grains per radiated volume were calibrated at several beamlines of SPring-8 and Photon Factory. Based on the relationships, we examined kinetics of grain growth in ice VI and VII, and kinetics of the ice VI-VII and VI-VIII transformations, from the evolution of the number of diffraction spots. Preliminary results on these kinetic experiments are presented in this paper.
    Journal of Physics Conference Series 04/2010; 215(1):012022.
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    ABSTRACT: On constructing a microgrid, it is essential to balance capacity of photovoltaic power generation (PV) systems and storage batteries in accordance with a control target. In the present study, we constructed a simulation model of energy control system in the microgrid. By using this model, we investigated the acceptable capacity of PV systems according the capacity of NaS battery for keeping the target supply-demand power imbalance over 30-min. within ±3 %. Under keeping the control target of power imbalance over 30 min. within ±3 %, we verified the relation between acceptable capacity of PV systems and NaS battery in a microgrid as follows. (1) the minimum required capacity of NaS battery in relation to the capacity of installed PV systems (330 kW) is of the order of ±20 kW, (2) the acceptable capacity of PV systems in relation to the capacity of installed NaS battery (±500 kW) is of the order of 890 kW. Moreover, we clarified the constrained conditions which impact to the power balancing in the microgrid according to the acceptable capacity of the PV systems.
    01/2010;
  • T. Kato, T. Inoue, Y. Suzuoki
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    ABSTRACT: Power output fluctuation of photovoltaic power generation systems (PVSs) may cause negative impact on the load frequency control of existing electric power system when the penetration of PVSs is quite large. For the cost-effective mitigation, the proper evaluation of apparent electricity load fluctuation property is very important, taking PVSs power output into account as negative load. Considering the independency of fluctuation patterns of insolation among various locations, this study evaluates the standard deviation of total power output fluctuation of PVSs by using the multi-point observation data of insolation. The diversity of PVSs penetration in the wide area is taken into account based on the statistical data of distribution of residences. Then, by taking the standard deviation of electricity load into account, this study discusses the impact of large-scale penetration of PVSs on the load frequency control.
    01/2010;
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    ABSTRACT: We have been developing a light weight and high efficiency superconducting traction transformer for railway rolling stock. We designed and fabricated a prototype superconducting traction transformer of a floor-mount type for Shinkansen rolling stock in 2004. We performed the type-test, the system-test, and the vibration-test. Consequently, we could verify that the transformer satisfied the requirement almost exactly as initially planned. However, there have been raised some problems to be solved to put superconducting traction transformer into practical use such that AC loss of the superconducting tape must be lower and the capacity of the refrigerator must be larger. Especially it is the most important to reduce the AC loss of superconducting windings for lightweight and high efficiency. The AC loss must be reduced near the theoretical value of superconducting tape with multifilament. In this study, we fabricated and evaluated the Bi2223 tapes as introduced various measures to reduce the AC loss. We confirmed that the AC loss of the narrow type of Bi2223 tapes with twist of filaments is lower, and we fabricated windings of this tape for use in superconducting traction transformer.
    Journal of Physics Conference Series 01/2010; 234(3).

Publication Stats

2k Citations
631.41 Total Impact Points

Institutions

  • 1991–2013
    • Gifu University Hospital
      Gihu, Gifu, Japan
  • 1993–2012
    • Nagoya University
      • • Department of Electrical Engineering and Computer Science
      • • Center for Integrated Research in Science and Engineering (CIRSE)
      Nagoya, Aichi, Japan
    • Toshiba Corporation
      Edo, Tōkyō, Japan
  • 2004–2010
    • Kyushu University
      • Department of Earth and Planetary Sciences
      Fukuoka-shi, Fukuoka-ken, Japan
    • University of California, Irvine
      • Department of Physics and Astronomy
      Irvine, CA, United States
    • University of Leicester
      • Department of Engineering
      Leicester, ENG, United Kingdom
  • 2001–2010
    • Japan Fine Ceramics Center
      Nagoya, Aichi, Japan
    • Nagoya Second Red Cross Hospital
      Nagoya, Aichi, Japan
  • 2009
    • Kyoto University
      Kioto, Kyōto, Japan
    • Fujikura Ltd.
      Edo, Tōkyō, Japan
  • 2003–2008
    • State University of New York
      New York City, New York, United States
  • 1995–2006
    • The University of Tokyo
      • • Institute for Cosmic Ray Research
      • • Faculty & Graduate School of Medicine
      Tokyo, Tokyo-to, Japan
  • 2003–2004
    • Niigata University
      • Division of Digestive and General Surgery
      Niahi-niigata, Niigata, Japan
  • 2002
    • Sumitomo Heavy Industries, Ltd
      Edo, Tōkyō, Japan
    • Japan Atomic Energy Agency
      • Quantum Beam Science Directorate
      Muramatsu, Niigata, Japan
    • Aichi Cancer Center
      Ōsaka, Ōsaka, Japan
  • 1998–2002
    • University of Tsukuba
      • Institute of Internet Science
      Tsukuba, Ibaraki, Japan
  • 1990–2000
    • Nagoya City University
      • Medical School
      Nagoya, Aichi, Japan
  • 1995–1999
    • Tohoku University
      • Graduate School of Science
      Japan
    • St. Marianna University School of Medicine
      • • Institute of Medical Science
      • • Department of Medicine
      Japan
  • 1997
    • Kyushu Institute of Technology
      Иидзука, Fukuoka, Japan
  • 1985
    • Nihon University
      Edo, Tōkyō, Japan
    • Obninsk Institute of Atomic Energy
      Moskva, Moscow, Russia