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Journal Articles

Conformational ensemble of a multidomain protein explored by Gd$$^{3+}$$ electron paramagnetic resonance

Saio, Tomohide*; Hiramatsu, Soya*; Asada, Mizue*; Nakagawa, Hiroshi; Shimizu, Kazumi*; Kumeta, Hiroyuki*; Nakamura, Toshikazu*; Ishimori, Koichiro*

Biophysical Journal, 120(15), p.2943 - 2951, 2021/08

 Times Cited Count:0 Percentile:0.01(Biophysics)

A rigid double-arm lanthanide tag was utilized in electron paramagnetic resonance spectroscopy to measure the distance between two specific points on a protein, and conformational states and distribution of a multi-domain protein enzyme MurD was investigated. Although the previous crystallographic and NMR studies have reported the three distinct conformational states of MurD, our data unveiled that the protein exists in much more variety of conformational states in the absence of the ligand. Given the fact that MurD is one of the potent drug target for infectious diseases, the finding in this study will provide important structural basis for drug development.

Journal Articles

Structural insight into proline cis/trans isomerization of unfolded proteins catalyzed by the Trigger Factor chaperone

Kawagoe, Soichiro*; Nakagawa, Hiroshi; Kumeta, Hiroyuki*; Ishimori, Koichiro*; Saio, Tomohide*

Journal of Biological Chemistry, 293(39), p.15095 - 15106, 2018/09

 Times Cited Count:14 Percentile:50.84(Biochemistry & Molecular Biology)

Molecular chaperones often possess functional modules that are specialized in assisting the formation of specific structural elements, such as a disulfide bridges and peptidyl-prolyl bonds in cis form, in the client protein. A ribosome-associated molecular chaperone Trigger Factor (TF), which has a peptidyl-prolyl cis/trans isomerase (PPIase) domain (PPD), acts as a highly efficient catalyst in the folding process limited by peptidyl-prolyl isomerization. Herein we report a study on the mechanism through which TF recognizes the proline residue in the unfolded client protein during the cis/trans isomerization process. The solution structure of TF in complex with the client protein showed that TF recognizes the proline-aromatic motif located in the hydrophobic stretch of the unfolded client protein through its conserved hydrophobic cleft, which suggests that TF preferentially accelerates the isomerization of the peptidyl-prolyl bond that is eventually folded into the core of the protein in its native fold. Molecular dynamics simulation revealed that TF exploits the backbone amide group of I195 to form an intermolecular hydrogen bond with the carbonyl oxygen of the amino acid residue preceding the proline residue at the transition state, which presumably stabilizes the transition state and thus accelerates the isomerization. The importance of such intermolecular hydrogen bond formation during the catalysis was further corroborated by the activity assay and NMR relaxation analysis.

Journal Articles

Three-dimensional electronic structures and the metal-insulator transition in Ruddlesden-Popper iridates

Yamasaki, Atsushi*; Fujiwara, Hidenori*; Tachibana, Shoichi*; Iwasaki, Daisuke*; Higashino, Yuji*; Yoshimi, Chiaki*; Nakagawa, Koya*; Nakatani, Yasuhiro*; Yamagami, Kohei*; Aratani, Hidekazu*; et al.

Physical Review B, 94(11), p.115103_1 - 115103_10, 2016/11

AA2016-0587.pdf:2.55MB

 Times Cited Count:17 Percentile:61.47(Materials Science, Multidisciplinary)

In this study, we systematically investigate three-dimensional(3D) momentum-resolved electronic structures of Ruddlesden-Popper-type iridium oxides Sr$$_{n+1}$$Ir$$_{n}$$O$$_{3n+1}$$ using soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES). Our results provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO$$_{2}$$-plane structure. This transition occurs when the spin-orbit-coupled $$j_{eff}$$ = 1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO$$_{3}$$ and $$k_{z}$$-dependent oscillations of photoelectron intensity in Sr$$_{3}$$Ir$$_{2}$$O$$_{7}$$. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole Brillouin zone and provides a panoramic view of electronic structures.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:176 Percentile:99.41(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:7 Percentile:49.81(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Degradation of hydroxymaleimide in 2-propanol by irradiation of energetic heavy ions, 2; N$$_{2}$$-saturated system

Nakagawa, Seiko*; Taguchi, Mitsumasa; Hirota, Koichi; Murakami, Takeshi*

Radiation Physics and Chemistry, 79(8), p.890 - 893, 2010/08

 Times Cited Count:3 Percentile:24.16(Chemistry, Physical)

Hydroxymaleimide was irradiated in N$$_{2}$$-saturated 2-propanol solutions by high-energy heavy ions over a wide range of LET values. The differential G-values of the degradation of hydroxymaleimide by irradiation with the heavier ions were lower than those of the lighter ions for the same LET value. It was opposite result obtained in the air-saturated system. The degradation efficiency was 1.5 times higher, when the dose rate was 1/10 times lower. When irradiated at an LET value lower than 8 eV/nm, the G-values converged to a value less than that obtained by $$gamma$$-irradiation.

JAEA Reports

Conceptual study for new $$^{99}$$Mo-production facility in JMTR

Kimura, Akihiro; Iimura, Koichi; Hosokawa, Jinsaku; Izumo, Hironobu; Hori, Naohiko; Nakagawa, Tetsuya; Kanno, Masaru; Ishihara, Masahiro; Kawamura, Hiroshi

JAEA-Review 2009-072, 18 Pages, 2010/03

JAEA-Review-2009-072.pdf:9.29MB

JAEA has a plan to produce $$^{99}$$Mo, a parent nuclide of $$^{99m}$$Tc. At present, radioisotopes are indispensable for a diagnosis and treatment in the medical field. Demand of $$^{99m}$$Tc (half life 6h) used as a radiopharmaceutical increases up year by year. Moreover, the expansion of demand will be expected in future. However, the supply of $$^{99}$$Mo in Japan depends fully on the import from foreign countries. Therefore, it is necessary to supply $$^{99}$$Mo stably by the domestic production. There are two methods of $$^{99}$$Mo (half life 65.9h) production; the one is the nuclear fission (n,fiss) method, and the other is the (n,$$gamma$$) method using the $$^{98}$$Mo target. $$^{99}$$Mo production in the JMTR with the (n,$$gamma$$) method was studied and evaluated. As a result, it was found that the partial amount of $$^{99}$$Mo demand is possible to supply stably if a new hydraulic-rabbit-irradiation-facility (HR) is used.

Journal Articles

Thermal-hydraulic research in JAEA; Issues and future directions

Akimoto, Hajime; Ohshima, Hiroyuki; Kamide, Hideki; Nakagawa, Shigeaki; Ezato, Koichiro; Takase, Kazuyuki; Nakamura, Hideo

Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 7 Pages, 2009/09

Thermal-hydraulics researches at JAEA are performed in many nuclear R&D areas that investigate fusion reactor, fast reactors (FR), high temperature gas cooled reactors (HTGR), and light water reactors (LWRs). These researches are composed of both experimental and analytical efforts. Experimental efforts cover from small-scale fundamental works to large-scale system-integrated tests. Analytical efforts cover both so-called one-dimensional system analysis codes and detailed three-dimensional CFD codes. The thermal-hydraulic phenomena dealt at JAEA cover both normal operation conditions and accident conditions including severe accidents in LWR and FR. The phenomena include single phase flow of water, supercritical water, helium and sodium, two-phase flow of steam-water or sodium-argon, and multi-phase flows encountered in severe accidents. In this paper, we will summarize current status and future directions of thermal-hydraulic researches at JAEA.

JAEA Reports

Investigation and design of the dismantling process of irradiation capsules containing tritium, 2; Detailed design and trial fabrication of capsule dismantling apparatus and investigation of glove box facility

Hayashi, Kimio; Nakagawa, Tetsuya; Onose, Shoji; Ishida, Takuya; Nakamichi, Masaru; Katsuyama, Kozo; Iwamatsu, Shigemi; Hasegawa, Teiji; Kodaka, Hideo; Takatsu, Hideyuki; et al.

JAEA-Technology 2009-007, 168 Pages, 2009/03

JAEA-Technology-2009-007.pdf:31.88MB

In-pile functional tests of breeding blankets have been planned by Japan Atomic Energy Agency (JAEA), using a test blanket module (TBM) which will be loaded in the International Thermonuclear Experimental Reactor (ITER). In preparation for the in-pile functional tests, JAEA has been being performed irradiation experiments of lithium titanate (Li$$_{2}$$TiO$$_{3}$$), which is the first candidate of solid breeder materials for the blanket of the demonstration reactor (DEMO) under designing in Japan. The present report describes (1) results of a detailed design and trial fabrication tests of a dismantling apparatus for irradiation capsules which were used in irradiation experiments by the Japan Materials Testing Reactor (JMTR) of JAEA, and (2) results of a preliminary investigation of a glove box facility for post-irradiation examinations (PIEs). In the detailed design of the dismantling apparatus, datailed specifications and the installation methods were examined, based on results of a conceptual design and basic design. In the trial fabrication, cutting tests were curried out by making a mockup of a cutting component. Furthermore, a preliminary investigation of a glove box facility was carried out in order to secure a facility for PIE work after the capsule dismantling, which revealed a technical feasibility.

Journal Articles

Development and design for Mo-production facility in JMTR

Iimura, Koichi; Hosokawa, Jinsaku; Izumo, Hironobu; Hori, Naohiko; Nakagawa, Tetsuya; Kanno, Masaru; Kawamura, Hiroshi

JAEA-Conf 2008-010, p.251 - 258, 2008/12

At Oarai Research and Development Center, Japan Atomic Energy Agency (JAEA) being advanced is the plan of refurbishing Japan Materials Testing Reactor (JMTR) to start the operation in FY 2011. As one of effective use of the JMTR, JAEA has a plan to product $$^{99}$$Mo, a parent nuclide of $$^{99m}$$Tc. $$^{99m}$$Tc is most commonly used as a radiopharmaceutical in the field of nuclear medicine. Currently the supplying of $$^{99}$$Mo depends only on imports from foreign countries, therefore JAEA is aiming at domestic production of a part of $$^{99}$$Mo in cooperation with industrial users. As JAEA's activities, mentioned are the process, the selection and fabric of the irradiation facilities for $$^{99}$$Mo production, the technical study of commercializing equipment after irradiation, and the cost evaluation for $$^{99}$$Mo production.

Journal Articles

Analysis on temperature distribution of reactor vessel cooling system during loss of coolant flow in HTTR

Takeda, Tetsuaki*; Ichimiya, Koichi*; Nishio, Hitoshi*; Nakagawa, Shigeaki; Takamatsu, Kuniyoshi

Proceedings of 7th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-7) (CD-ROM), 11 Pages, 2008/10

Safety demonstration tests using the HTTR (High Temperature Engineering Test Reactor) are being performed to verify the inherent safety features and to validate the numerical code for the safety assessment of the VHTR (Very High Temperature Reactor). The partial loss of coolant flow test was performed under the condition of the ATWS (Anticipated Transient without Scram). We are planning to perform the test of loss of coolant flow and stopping the vessel cooling system (VCS). The test of the loss of coolant flow as one of safety demonstration tests is carried out by tripping all gas circulators, and the stopping VCS test is performed continuously after the loss of coolant flow. The objective of this study is to evaluate the temperature distribution of the reactor pressure vessel (RPV) and the VCS during the tests. It is necessary to consider the effect of thermal radiation from the RPV for evaluation of temperature of the VCS and concrete vessel.

Journal Articles

Degradation of hydroxymaleimide in 2-propanol by irradiation of energetic heavy ions, 1; Air-saturated system

Nakagawa, Seiko*; Taguchi, Mitsumasa; Ota, Nobuaki*; Hirota, Koichi

Radiation Physics and Chemistry, 77(10-12), p.1230 - 1232, 2008/10

 Times Cited Count:4 Percentile:29.54(Chemistry, Physical)

Hydroxymaleimide was irradiated in air-saturated 2-propanol solution by high-energy heavy ions. The differential ${it G}$-values of the degradation of hydroxymaleimide was smaller than the ${it G}$-value obtained by $$gamma$$-irradiation, and decreased with increasing LET value for the same kind of ions. The fitting curve of the differential ${it G}$-values obtained for He ion is shifted from that for heavier ions. The irradiation effects of the kind and LET value of ions were observed on the degradation of hydroxymaleimide.

JAEA Reports

Conceptual study of $$^{99}$$Mo production facility in JMTR

Iimura, Koichi; Hosokawa, Jinsaku; Kanno, Masaru; Kitajima, Toshio; Nakagawa, Tetsuya; Sakamoto, Taichi; Hori, Naohiko; Kawamura, Hiroshi

JAEA-Technology 2008-035, 47 Pages, 2008/06

JAEA-Technology-2008-035.pdf:7.91MB

At Oarai Research and Development Center, Japan Atomic Energy Agency (JAEA) advances the plan of refurbishing Japan Materials Testing Reactor (JMTR) to start the operation in fiscal 2011. As part of effective use for JMTR, JAEA is planning to product $$^{99}$$Mo, which is a parent nuclide of $$^{rm 99m}$$Tc. $$^{rm 99m}$$Tc is most commonly used as a radiopharmaceutical in the field of nuclear medicine. Currently the supplying of $$^{99}$$Mo is only depend on imports from foreign countries, so JAEA is aiming at domestic production of a part of $$^{99}$$Mo in cooperation with the industrial circles. In this article, JAEA described the process, the choice and fabric of the irradiation facilities for $$^{99}$$Mo production, the technical study of commercializing equipment after irradiation, and the cost study for $$^{99}$$Mo production.

Journal Articles

LET effect on irradiation of hydroxymaleimide in alcohol solution

Nakagawa, Seiko*; Ota, Nobuaki*; Taguchi, Mitsumasa; Hirota, Koichi

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 159, 2008/03

no abstracts in English

Journal Articles

Measurement of residual stress on a unidirectional solidified Al$$_{2}$$O$$_{3}$$/YAG eutectic composite using synchrotron and neutron diffraction

Suzuki, Hiroshi; Waku, Yoshiharu*; Nakagawa, Narihito*; Akita, Koichi*; Moriai, Atsushi; Morii, Yukio

Journal of Neutron Research, 15(2), p.113 - 120, 2007/06

The residual stress in only YAG phase was measured on the surface of the Al$$_{2}$$O$$_{3}$$-Y$$_{3}$$Al$$_{5}$$O$$_{12}$$(YAG) eutectic composite(Al$$_{2}$$O$$_{3}$$/YAG MGC) using the low energy synchrotron X-rays. The residual stresses in plane stress condition were significantly different between top and side surfaces of the specimen. Therefore, an anisotropic triaxial residual stress probably exists within the MGC. The residual stress within the MGC was also measured using a neutron diffraction. The residual stress in the YAG phase rose from compression in the solidification direction to tension in perpendicular direction. The residual stress in the Al$$_{2}$$O$$_{3}$$ phase was anisotropic compression and there was no tension in all directions. This anisotropic residual stress could be explained by the crystallographic anisotropy of thermal expansion in the Al$$_{2}$$O$$_{3}$$ phase. However, both phase stresses were not balanced, so that it is expected that there would be the stress distribution in MGC sample used in this study.

Journal Articles

Coolant chemistry of the High Temperature Gas-Cooled Reactor 'HTTR'

Sakaba, Nariaki; Nakagawa, Shigeaki; Furusawa, Takayuki*; Emori, Koichi; Tachibana, Yukio

Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.388 - 395, 2004/12

Chemistry control is important for the helium coolant of High Temperature Gas-cooled Reactors (HTGRs) because impurities cause oxidation of the graphite used in the core and corrosion of high temperature materials used in the heat exchanger. In the High Temperature Engineering Test Reactor (HTTR) which is the first HTGR in Japan, the chemical impurity concentration is restricted and its behaviour is monitored during reactor operations. The impurity is reduced by the helium purification system and the concentration is measured by the helium sampling system installed to the primary and secondary helium system, continuously. This paper describes the impurity behaviour during the rise-to-power test which is the initial power-up of the HTTR. Also, the amount of the emitted impurity to the primary circuit from the graphite component and insulator used at the concentric hot gas duct are evaluated. During the power up, any abnormal impurity increases were not obtained and the chemical composition of the primary circuit is sufficiently in the stability area to avoid carbon deposition.

Journal Articles

Fundamental experiments of Microwave thruster

Matsui, Makoto*; Mihara, Yorichika*; Nakagawa, Tatsuo*; Mori, Koichi*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi

Uchu Yuso Shimpojiumu (Heisei-14-Nendo) Koenshu, p.300 - 303, 2003/00

no abstracts in English

JAEA Reports

Investigation research of core-basic information associated with the coupling analysis; Outline report

Kataoka, Shinichi*; Kawahara, Kenichi*; Matsunaga, Kenichi*; Ishihara, Yoshinao*; Neyama, Atsushi*; Nakagawa, Koichi*; Iwata, Hiroshi*; Mori, Koji*

JNC TJ8400 2001-037, 33 Pages, 2001/03

JNC-TJ8400-2001-037.pdf:2.02MB

no abstracts in English

JAEA Reports

Investigation research of core-basic information associated with the coupling analysis; result report

Kataoka, Shinichi*; Kawahara, Kenichi*; Matsunaga, Kenichi*; Ishihara, Yoshinao*; Neyama, Atsushi*; Nakagawa, Koichi*; Iwata, Hiroshi*; Mori, Koji*

JNC TJ8400 2001-036, 202 Pages, 2001/03

JNC-TJ8400-2001-036.pdf:7.58MB

The newest literature information in the foreign countries was researched, and this research showed the basic concept of the coupling analysis code to realize coupling analysis in near field of the geological disposal system. The outline of this research is shown in the following. (1)The combination of M (Mechanical) and (Chemistry) is placed on the weak relations, Because coupling analysis of the United States Yucca Mountain limits a site and the specifications of engineered barrier. (2)One of the purposes of this research is information collecting about coupling analysis code NUFT-C adopted in the United States Yucca Mountain. Therefore, we carried out an information exchange with the United States Lawrence Livermore National Laboratory. We could collect the development purpose of analysis code, key function, and information such as a test case analysis. (3)The investigation of the analysis code concerned with the newest information of coupling analysis which contains the geochemistry process and 2 phase system was done based on the public information for the purpose of building some concept of the coupling analysis code, the extraction of the development issues. It could be understood about the future development strategy and the precaution in addition to a phenomenon to deal with, the current status of the coupling analysis technique as a result of the investigation. (4)It was cleared about the mission of the coupling analysis code and the requirement items (function, quality) by this research. Then, some development options were presented. (5)It was studied about the procedure of developing it to satisfy the above requirement toward the conditions that a site isn't selected, the short development. The tool (Diffpack) which could cope with the speed-up of the calculation time and visualization flexibly was effective, and it was summarized about the test case by using this tool, the key function of this tool as that result.

JAEA Reports

Development of the evaluation methodology for earthquake resistance of the engineered barrier system (III)

Mori, Koji*; Neyama, Atsushi*; Nakagawa, Koichi*

JNC TJ8400 2000-064, 175 Pages, 2000/03

JNC-TJ8400-2000-064.pdf:5.23MB

In this study, the following tasks have been performed in order to evaluate the stability of earthquake resistance for the engineered barrier system(EBS) of High Level Waste (HLW) geological isolation system. (1)validation studies for the liquefaction model. The function of single-phase analysis without interaction between soil and pore water in three-dimensional effective stress analysis code, which had been developed in this study, have been verified using by actual vibration test data. This fiscal year, some validation studies for the function of liquefaction analysis was conducted usig by actual measured data through the laboratory liquefaction test. (2)Supplemental Studies for JNC Second Progress Report. Through the JNC second progress report, it was considered that the stability of earthquake resistance of the engineered barrier system would be maintained under the major seismic event. At the same time we have recognized that several model parameters for joint-crack element, which takes into account for the response behavior of material discontinuous surface such as between overpack and buffer material, will become important in the response behavior of the whole EBS. This year, we have studied about several topics, which arise from technical discussion on JNC second progress report and we have discussed about total seismic stability of EBS. (3)Supplemental Studies for joint study with NRIDP. At this fiscal year, the joint study with National Research Institute for Disaster Prevention (NRIDP) will be final stage. UP to this day, incremental validation studies had been continued using by mesuared data obtained from vibration test. In this final stage, validation analysis has been conducted again using by current version new analysis code and maintained the validation data which will be contribute to the joint study mentioned above.

31 (Records 1-20 displayed on this page)