S. Torii

Kyoto University, Kioto, Kyōto, Japan

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Publications (43)79.82 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Deuterated a -glycine was studied by high resolution neutron powder diffraction (NPD). We performed a careful data analysis by Rietveld refinement and compared the result with those of the previous neutron single crystal (NSD) studies. The comparison demonstrates that the deviation of NPD study is generally within 1.2% from the NSD studies, indicating high resolution NPD is by no means inferior to NSD in studying small organic molecular crystals.
    Journal of Physics Conference Series 04/2014; 502(1):012055.
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    ABSTRACT: SPICA, a new special environment powder neutron diffractometer was built at BL09 in the Material and Life science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). This is the first instrument dedicated solely to the study of next-generation batteries in J-PARC and is optimized for in situ measurements to clarify structural changes of materials in batteries. The basic design and instrumentation of SPICA have been completed. The highest Δd/d resolution achieved at the commissioning stage was 0.09% at the back scattering bank of SPICA. The reliability of the diffraction data has achieved a sufficiently high level for the structural analysis of materials using the Rietveld method. The air scattering banks with the blades made of B4C for in situ measurements also function very well.
    Journal of Physics Conference Series 04/2014; 502(1):012053.
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    ABSTRACT: Super High Resolution Powder Diffractometer SuperHRPD [1] at J-PARC have suffered damage by the Great East Japan Earthquake on 11 March 2011. After temporarily restoration work, the general user program has been started since April 2012. Full-fledged restoration of the temporarily restored devices is being carried out in 2013. The absorber materials for two disk choppers were replaced to 10B4C which improved quality of incident spectrum. The new detector system of 8 mm diameter position sensitive detectors was developed, and the test experiments showed excellent results.
    Journal of Physics Conference Series 04/2014; 502(1):012052.
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    ABSTRACT: In this work, spinel LiMn2O4 powder was synthesized from LiOH·H2O and MnOx by mechanical alloying (MA) for various MA times. The stoichiometry and crystal structure of the spinel were examined and their relation to the electrochemical behavior of the spinel was investigated. In this study, we find that, as a result of MA using stainless steel jar and balls, Fe and Cr contents increased and O content decreased with increasing MA time. The results from electrochemical study show that the stoichiometry of the spinel is closely related to the decreasing of initial discharge capacity and cyclic performance of the spinel.
    Solid State Ionics 01/2014; 262:83–87. · 2.05 Impact Factor
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    ABSTRACT: We present observations of a transient He-like Fe K alpha absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the start and the end of the episodic accretion phenomena or dips for the first time. We model the X-ray spectra during the event and trace their evolution. The absorption line is rather weak in the first half of the observation, but instantly deepens for ~10 ks, and weakens thereafter. The overall change in equivalent width is a factor of ~3, peaking at an orbital phase of ~0.08. This is evidence that the companion stellar wind feeding the black hole is clumpy. By analyzing the line with a Voigt profile, it is found to be consistent with a slightly redshifted Fe XXV transition, or possibly a mixture of several species less ionized than Fe XXV. The data may be explained by a clump located at a distance of ~10^(10-12) cm with a density of ~10^((-13)-(-11)) g cm^-3, which accretes onto and/or transits the line-of-sight to the black hole, causing an instant decrease in the observed degree of the ionization and/or an increase in density of the accreting matter. Continued monitoring for individual events with future X-ray calorimeter missions such as ASTRO-H and AXSIO will allow us to map out the accretion environment in detail and how it changes between the various accretion states.
    The Astrophysical Journal Letters 04/2013; 767(2). · 6.35 Impact Factor
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    ABSTRACT: Rapid spectral changes in the hard X-ray on a time scale down to ~0.1 s are studied by applying "shot analysis" technique to the Suzaku observations of the black hole binary Cygnus X-1, performed on 2008 April 18 during the low/hard state. We successfully obtained the shot profiles covering 10--200 keV with the Suzaku HXD-PIN and HXD-GSO detector. It is notable that the 100-200 keV shot profile is acquired for the first time owing to the HXD-GSO detector. The intensity changes in a time-symmetric way, though the hardness does in a time-asymmetric way. When the shot-phase-resolved spectra are quantified with the Compton model, the Compton y-parameter and the electron temperature are found to decrease gradually through the rising phase of the shot, while the optical depth appears to increase. All the parameters return to their time-averaged values immediately within 0.1 s past the shot peak. We have not only confirmed this feature previously found in energies below ~60 keV, but also found that the spectral change is more prominent in energies above ~100 keV, implying the existence of some instant mechanism for direct entropy production. We discuss possible interpretations on the rapid spectral changes in the hard X-ray band.
    The Astrophysical Journal Letters 04/2013; 767(2). · 6.35 Impact Factor
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    ABSTRACT: Astro-H is the sixth Japanese X-ray space observatory which will be launched in 2014. Two of onboard instruments of Astro-H, Hard X-ray Imager and Soft Gamma-ray Detector are surrounded by many number of large Bismuth Germanate (Bi4Ge3O12; BGO) scintillators. Optimum readout system of scintillation lights from these BGOs are essential to reduce the background signals and achieve high performance for main detectors because most of gamma-rays from out of field-of-view of main detectors or radio-isotopes produced inside them due to activation can be eliminated by anti-coincidence technique using BGO signals. We apply Avalanche Photo Diode (APD) for light sensor of these BGO detectors since their compactness and high quantum efficiency make it easy to design such large number of BGO detector system. For signal processing from APDs, digital filter and other trigger logics on the Field-Programmable Gate Array (FPGA) is used instead of discrete analog circuits due to limitation of circuit implementation area on spacecraft. For efficient observations, we have to achieve as low threshold of anti-coincidence signal as possible by utilizing the digital filtering. In addition, such anti-coincident signals should be sent to the main detector within 5μs to make it in time to veto the A–D conversion. Considering this requirement and constraint from logic size of FPGA, we adopt two types of filter, 8 delay taps filter with only 2 bit precision coefficient and 16 delay taps filter with 8 bit precision coefficient. The data after former simple filter provides anti-coincidence signal quickly in orbit, and the latter filter is used for detail analysis after the data is down-linked.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2013; 699:112–115. · 1.14 Impact Factor
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    ABSTRACT: We analyzed high-quality broadband (0.5--300 keV) Suzaku data of Cyg X-1, acquired on 25 occasions in its low/hard state from 2005 to 2009 with a total exposure of ~ 450 ks. Unified spectral and timing analyses of these data sets revealed convincing evidence for a stable accretion disk and inhomogeneous coronae, reinforcing the view described in Makishima et al. (2008). Specifically, we found three different types of spectral changes on distinct time scales: (1) a clear enhancement of soft X-ray signals over 2-10 on long time scales (> days), (2) a sharp decrease of variability in energies of 0.5-2 keV on a short (~1s) time scale, and (3) a rapid decrease of electron temperature and/or optical depth of the corona on an even shorter time scales (<<1s). Among them, (1) means the presence of a softer Compton component and its long-term evolution. This implies that the overall corona is inhomogeneous, and is characterized by multiple values of optical depths and/or temperatures. In contrast, (2) can be interpreted as clear evidence for the presence of a stable disk emission at the softest end of the Suzaku spectra. The result (3) also provides some clues to the property of the corona.
    09/2012;
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    ABSTRACT: Osteoarthritis patients may exhibit different kinematics according to the disease stage. However, changes in the frontal and horizontal planes in each stage remain unclear. The purpose of this study was to investigate changes in the knee kinematic gait variables of osteoarthritis patients, including the frontal and horizontal planes, with respect to the severity of the disease. Forty-five patients with knee osteoarthritis and 13 healthy young subjects were recruited for the experiment. All subjects were examined while walking on a 10-m walkway at a self-selected speed. In each trial, we calculated the angular displacements of flexion/extension, abduction/adduction, and external/internal tibial rotation. We also measured muscle strength, range of motion (ROM), and alignment. We compared the differences in osteoarthritis severity and knee kinematic variables between osteoarthritis patients and normal subjects. The flexion angle at the time of foot contact was significantly less in patients with severe and moderate osteoarthritis than in normal subjects (both p<0.01). The abduction angle at the 50% stance phase was significantly less in patients with severe osteoarthritis than in normal subjects (p<0.05). The excursion of axial tibial rotation was significantly less in patients with early osteoarthritis than in normal subjects (p<0.05). Osteoarthritis patients had different knee kinematics during gait, depending on the progress of osteoarthritis. Early-stage patients exhibit decreased axial tibial rotation excursion, while severe-stage patient exhibit increased knee adduction.
    The Knee 12/2011; 19(5):628-32. · 2.01 Impact Factor
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    ABSTRACT: We examined muscle-specific ubiquitin ligases MAFbx/Atrogin-1 and MuRF1 gene expression resulting from immobilization-induced skeletal muscle atrophy of slow-twitch soleus and fast-twitch plantaris muscles. Male C57BL/6 mice were subjected to hindlimb immobilization, which induced similar percentage decreases in muscle mass in the soleus and plantaris muscles. Expression of MAFbx/Atrogin-1 and MuRF1 was significantly greater in the plantaris muscle than in the soleus muscle during the early stage of atrophy. After a 3-day period of atrophy, total FOXO3a protein level had increased in both muscles, while phosphorylated FOXO3a protein had decreased in the plantaris muscle, but not in the soleus muscle. PGC-1α protein expression did not change following immobilization in both muscles, but basal PGC-1α protein in the soleus was markedly higher than that in plantaris muscles. These data suggest that although soleus and plantaris muscles atrophied to a similar extent and that muscle-specific ubiquitin protein ligases (E3) may contribute more to the atrophy of fast-twitch muscle than to that of slow-twitch muscle during immobilization.
    The Journal of Physiological Sciences 09/2011; 61(6):537-46. · 1.09 Impact Factor
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    ABSTRACT: The present study was performed to develop regression-based prediction equations for fat mass by ultrasound in Japanese children and to investigate the validity of these equations. A total of 127 healthy Japanese pre-pubertal children aged 6-12 years were randomly separated into two groups: the model development group (fifty-four boys and forty-four girls) and the validation group (eighteen boys and eleven girls). Total body, trunk, arm and leg fat masses were initially determined by dual-energy X-ray absorptiometry (DXA, Delphi A-QDR whole-body scanner; Hologic, Inc., Bedford, MA, USA). Then, fat thickness was measured by B-mode ultrasound (5 MHz scanning head) at nine sites (arm: lateral forearm, anterior and posterior upper arm; trunk: abdomen and subscapular; leg: anterior and posterior thigh, anterior and posterior lower leg). Regression analyses were used to describe the relationships between the site-matched fat masses (total body, arm, trunk and leg) obtained by DXA and ultrasound in the development group. When these fat mass prediction equations were applied to the validation group, the measured total and regional fat mass was very similar to the predicted fat mass (mean difference calculated as predicted - measured fat mass ± 2 SD; total body 0·1 (SD 0·5) kg, arm 0·1 (SD 0·3) kg, trunk - 0·1 (SD 0·3) kg, leg 0·1 (SD 0·5) kg for boys; total body 0·5 (SD 1·3) kg, arm 0·0 (SD 0·3) kg, trunk 0·1 (SD 0·8) kg, leg 0·3 (SD 0·6) kg for girls), and the Bland-Altman analysis did not indicate a bias. These results suggest that ultrasound-derived prediction equations for boys and girls are useful for estimating total and regional fat mass.
    The British journal of nutrition 05/2011; 106(6):944-50. · 3.45 Impact Factor
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    ABSTRACT: The present study was performed to develop regression based prediction equations for fat mass from skinfold thickness in Japanese children, and to investigate the cross-sectional and longitudinal validity of these equations. A total of 127 healthy Japanese prepubertal children aged 6-12 years were randomly separated into two groups: the model development group (54 boys and 44 girls) and the cross-sectional validation group (18 boys and 11 girls). Fat mass was initially determined by using DXA (Hologic Delphi A-QDR whole-body scanner) to provide reference data. Then, fat thickness was measured at triceps and subscapular using an Eiken-type skinfold calipers. Multiple anthropometric and DXA measures were obtained one year later for 28 of the original 127 subjects (longitudinal validation group: 14 boys and 14 girls). Strong significant correlations were observed between total fat mass by DXA measurement and the skinfold thickness × height measures by caliper in the model development group of boys and girls (R2=0.91-0.92, p<0.01). When these fat mass prediction equations were applied to the cross-sectional and longitudinal validation groups, the measured total fat mass was also very similar to the predicted fat mass. In addition, there were significant correlations between the measured and predicted total fat mass for boys and girls, respectively, although Bland-Altman analysis indicated a bias in cross-sectional validation group. Skinfold-derived prediction equations underestimate for obese children but are generally useful for estimating total fat mass in field research.
    Asia Pacific Journal of Clinical Nutrition 01/2011; 20(3):426-31. · 1.06 Impact Factor
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    ABSTRACT: Over the past 3 decades, the Low/Hard state of black hole binaries has remained rather poorly understood. This limitation is now being overcome by the wide-band capability of Suzaku. In fact, a Suzaku observation of Cyg X-1 in the Low/Hard state led to a view that an optically- thick disk partially intrudes into a hot corona, the disk is truncated at 10 gravitational radii, and the corona is highly inhomogeneous (Makishima+08). From 2005 to 2009, Cyg X-1 was observed 25 times with Suzaku. The source meanwhile stayed mostly in the Low/Hard state, but approached the Soft state on June 2009. We applied a unified spectral and timing analysis to all these data sets. The results suggest that, as the 2-10 keV luminosity increases, (1) the corona shrinks, (2) the inner radius of the optically-thick disk decreases, and (3) the disk intrudes deeper into the corona. These results will be much enhanced through a collaboration between MAXI and Suzaku. For example, we may select a transition phase from the Low/Hard state to the High/Soft state, and examine how the Comptonized hard continuum in the former state turns into the enigmatic steeper hard-tail emission which is seen in the latter state.
    12/2010;
  • Zeitschrift fur Kristallographie Supplements. 09/2009; 2009(30).
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    ABSTRACT: During thunderstorms on 20 September 2008, a simultaneous detection of gamma rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 sec, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung gamma rays arriving from a source which is 60-130 m in distance at 90% confidence level. The observed electrons are likely to be dominated by a primary population escaping from an acceleration region in the clouds.
    Physical Review Letters 07/2009; 102(25):255003. · 7.73 Impact Factor
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    ABSTRACT: The purpose of this study was to investigate the effect of intensive eccentric exercise on hamstring muscles by using magnetic resonance imaging (MRI) and to elucidate the relationships between the changes in the electromyographic (EMG) parameters and in the transverse relaxation time (T2) of the hamstring muscles. Seven male volunteers performed eccentric knee flexion exercise, and the EMG activity of the hamstring muscles was simultaneously measured. Before and immediately after the exercise, the maximum isometric knee flexion torque was measured and MR images of the hamstring muscles were obtained. For all hamstring muscles, the EMG activity of the fifth set was significantly lower than that of the first set. For each subject, a significant correlation was detected between the percentage change in the value of the post-exercise T2 value and those of EMG signals during the exercise only for the semitendinosus (ST) muscle and not for the biceps femoris (BF) and the semimembranosus (SM) muscles. These results suggested that the EMG-activity reductions in the BF, ST, and SM muscles were due to neuromuscular fatigue, and moreover the reduction in the ST muscle was due to a failure in the E-C coupling, which was caused by excessive muscle-fiber damage.
    International Journal of Sports Medicine 04/2009; 30(7):533-7. · 2.27 Impact Factor
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    ABSTRACT: The semitendinosus (ST) muscle has a tendinous intersection within the muscle belly that separates the ST muscle into distinct proximal and distal compartments. Thus far, no study has compared the electromyographic (EMG) activities between the proximal and distal compartments of the human ST muscle. This study aimed to investigate the intramuscular EMG activity patterns of the proximal and distal compartments of the ST muscle by altering the hip and knee joint positions. The study population comprised eight healthy male volunteers. They performed ramp isometric knee flexion tasks form the relaxed state to the maximal voluntary contraction (MVC) state with (1) the hip and knee at 90 degrees and 0 degrees, respectively (90-0 position), (2) both the hip and knee at 00 (0-0 position), and (3) the hip and knee at 0 degrees and 90 degrees, respectively (0-90 position). Fine-wire electrodes were inserted into the proximal and distal compartments of the ST muscle and the individual EMG activities were recorded. In the 90-0 position, the EMG activity of the distal compartment was higher than that of the proximal compartment at 60%, 80%, and 90% MVC. Moreover, in the 0-90 position, the EMG activity of the proximal compartment was higher than that of the distal compartment at 60% MVC. These results indicated that the lengthened or shortened muscle conditions induced regional differences in the EMG activity patterns, while the two compartments showed equivalent activity when the muscle length was moderate.
    Electromyography and clinical neurophysiology 01/2009; 49(4):149-54.
  • Medicine and Science in Sports and Exercise - MED SCI SPORT EXERCISE. 01/2009; 41.
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    ABSTRACT: During thunderstorms on 20 September 2008, a simultaneous detection of gamma rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 sec, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung gamma rays arriving from a source which is 60-130 m in distance at 90% confidence level. The observed electrons are likely to be dominated by a primary population escaping from an acceleration region in the clouds.
    Physical Review Letters - PHYS REV LETT. 01/2009; 102(25).
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    ABSTRACT: A new analysis software suite, Z-Code, is under development for powder diffraction data analyses in the Materials and Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC). This software suite comprises data processing, data analyses, graphical user interface and visualization software. As a part of Z-Code, a Rietveld analysis program for neutron (TOF and angle dispersive) and X-ray data, Z-Rietveld, has been developed. Here we report the basic traits and some significant features of Z-Rietveld.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2009; 600(1):94-96. · 1.14 Impact Factor

Publication Stats

166 Citations
79.82 Total Impact Points

Institutions

  • 2014
    • Kyoto University
      • Research Reactor Institute
      Kioto, Kyōto, Japan
  • 2009–2014
    • High Energy Accelerator Research Organization
      • Institute of Materials Structure Science
      Tsukuba, Ibaraki, Japan
  • 2009–2013
    • The University of Tokyo
      • Department of Physics
      Edo, Tōkyō, Japan
  • 2011
    • Niigata University of Health and Welfare
      Niahi-niigata, Niigata, Japan
  • 2005–2011
    • Waseda University
      • • Faculty of Sport Sciences
      • • Graduate School of Human Sciences
      Edo, Tōkyō, Japan
  • 2007
    • National Rehabilitation Center for Persons with Disabilities
      Tokorozawa, Saitama, Japan
  • 2006
    • Ibaraki University
      • Graduate School of Science and Engineering
      Mito-shi, Ibaraki, Japan