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Tomita, Masanori*; Matsumoto, Hideki*; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke*; Maeda, Munetoshi*; Kobayashi, Yasuhiko
Life Sciences in Space Research, 6, p.36 - 43, 2015/07
A radiation-induced bystander response is generally known as a cellular response induced in unirradiated cell by receiving bystander signaling factors released from directly irradiated cells of a cell population. Bystander responses induced by high-LET heavy ions at low fluence are an important problem concerning the health of astronauts in the space environment. Here we set out NO-mediated bystander signal transductions induced by high-LET heavy-ion microbeam irradiation in normal human fibroblasts. Our findings suggest that Akt- and NF-
B-dependent signaling pathway involving COX-2 plays an important role in the NO-mediated high-LET heavy-ion-induced bystander responses. Additionally, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells, which are distinguish form directly irradiated cells.
Matsumoto, Hideki*; Tomita, Masanori*; Otsuka, Kensuke*; Hatashita, Masanori*; Maeda, Munetoshi*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Ikeda, Hiroko; et al.
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 76, 2015/03
The objective of this project is to elucidate molecular mechanisms for the induction of radioadaptive response through radiation-induced bystander responses induced by irradiation with heavy ion microbeams in JAEA. We found that the adaptive response was induced by Ar (520 MeV 
Ar
) microbeam-irradiation of a limited number of cells, followed by the broad beam-irradiation and that the adaptive response was almost completely suppressed by the addition of carboxy-PTIO, as a nitric oxide (NO) scavenger. In addition, we found several genes induced specifically and preferentially when radioadaptive response could be induced. We confirmed that 
expression was specifically induced only when radioadaptive response could be induced. Our findings strongly suggested that radioadaptive response can be induced by NO-mediated bystander responses evoked by irradiation with heavy ion microbeams.
Matsumoto, Fumiko; Maeda, Kayo*; Chatake, Toshiyuki*; Maeda, Yuichiro*; Fujiwara, Satoru
Biochemical and Biophysical Research Communications, 382(1), p.205 - 209, 2009/04
Times Cited Count：15 Percentile：37.83(Biochemistry & Molecular Biology)Two cardiomyopathy-causing mutations, E244D and K247R, in human cardiac troponin T (TnT) are located in the coiled-coil region of the Tn-core domain. To elucidate effects of mutations in this region on the regulatory function of Tn, we measured Ca
-dependent ATPase activity of myofibrils containing various mutants of TnT at these residues. The results confirmed that the mutant E244D increases the maximum ATPase activity without changing the Ca sensitivity. The mutant K247R was shown for the first time to have the effect similar to the mutant E244D. Furthermore, various TnT mutants (E244D, E244M, E244A, E244K, K247R, K247E, and K247A) showed various effects on the maximum ATPase activity while the Ca sensitivity was unchanged. Molecular dynamics simulations of the Tn-core containing these TnT mutants suggested that the hydrogen-bond network formed by the side chains of neighboring residues around residues 244 and 247 is important for Tn to function properly.
Si/Ge hybrid structures and its degradationMaeda, Yoshihito; Jonishi, Takafumi*; Narumi, Kazumasa; Ando, Yuichiro*; Ueda, Koji*; Kumano, Mamoru*; Sado, Taizo*; Miyao, Masanobu*
Applied Physics Letters, 91(17), p.171910_1 - 171910_3, 2007/10
Times Cited Count：31 Percentile：72.67(Physics, Applied)The axial orientation of molecular-beam-epitaxy (MBE)-grown FeSi(111)/Ge(111) hybrid structures was investigated by Rutherford backscattering spectroscopy. We confirmed that during MBE above 300
C, the interdiffusion of Fe and Ge atoms results in a composition change and the epitaxial growth of FeGe in FeSi. Low-temperature (
200 C) MBE can realize fully ordered DO-FeSi with highly axial orientation [minimum yield (
)=2.2%]. Postannealing above 400 C results in a composition change and the degradation of axial orientation in the off-stoichiometric FeSi. The significance of stoichiometry with regard to thermal stability and the interfacial quality of FeSi(111)/Ge(111) hybrid structures was also discussed.
Ando, Yuichiro*; Ueda, Koji*; Kumano, Mamoru*; Sado, Taizo*; Narumi, Kazumasa; Maeda, Yoshihito; Miyao, Masanobu*
Shingaku Giho, 107(111), p.221 - 224, 2007/06
Ferromagnetic silicide FeSi (Currie temperature: 840 K) has three phases (A2, B2, and DO3), where the DO3-type is an ordered phase and calculated to be spin-polarized at the Fermi level. In addition, the lattice constant (0.565 nm) of FeSi is almost completely equal to that (0.565 nm) of Ge. Therefore, atomically controlled epitaxial growth of FeSi is expected on Ge. This will be a powerful tool to realize Ge channel spin transistors with ultrahigh speed operation and ultralow power consumption. This paper reviews our recent progress in novel epitaxial growth of FeSi on Ge for spintronics application.
Si/SiGe]
(n = 1-2) multi-layered structures for spintronics applicationSado, Taizo*; Ueda, Koji*; Ando, Yuichiro*; Kumano, Mamoru*; Narumi, Kazumasa; Maeda, Yoshihito; Miyao, Masanobu*
ECS Transactions, 11(6), p.473 - 479, 2007/00
Our recent progresses in epitaxial growth of FeSi on Ge substrates are reviewed. Single crystalline FeSi layers with atomically flat interfaces were achieved on Ge(111) substrates by optimizing growth conditions at low temperatures (60
200 C). Thermal stability of it was guaranteed up to 400 C. In addition, epitaxial growth of mixed layers composed of FeSi, FeGe, and FeSi on Ge substrates at 400 C is reported. Finally, epitaxial growth of FeSi/Ge/FeSi/Ge structures is discussed. These results will be a powerful tool to open up SiGe related spintronics.
Si on Ge substrateKumano, Mamoru*; Ando, Yuichiro*; Ueda, Koji*; Sado, Taizo*; Narumi, Kazumasa; Maeda, Yoshihito; Miyao, Masanobu*
ECS Transactions, 11(6), p.481 - 485, 2007/00
The effects of the Fe/Si ratios on molecular beam epitaxy (MBE) of FeSi on Ge substrate have been investigated in a wide range of growth temperatures (60300 C). From XRD measurements, it was found that FeSi layers were epitaxially grown on Ge(111) substrates at 60200 C under the stoichiometric (Fe:Si = 3:1) and non-stoichiometric (Fe:Si = 4:1) conditions. From RBS measurement, it was found that atomic mixing of Fe and Ge at FeSi/Ge interfaces began at a growth temperature of 300 C. In the case of MBE under the stoichiometric condition, the crystallinity of FeSi is significantly improved compared to the non-stoichiometric condition. As a result, very low 
was obtained in a wide temperature (60200 C) under the stoichiometric condition. From the transmission electron microscopy measurements, it was shown that high-quality DO3-type FeSi/Ge structures with atomically flat interfaces were realized at a low temperature (200 C) under the stoichiometric condition.
Matsumoto, Fumiko*; Makino, Koji*; Maeda, Kayo*; Patzelt, H.*; Maeda, Yuichiro*; Fujiwara, Satoru
Journal of Molecular Biology, 342(4), p.1209 - 1221, 2004/09
Times Cited Count：19 Percentile：29.79(Biochemistry & Molecular Biology)Regulation of skeletal and cardiac muscle contraction is associated with the thin filament-based proteins, troponin C (TnC), TnI, TnT, tropomyosin, and actin. Knowledge of 
structures of these proteins is indispensable for elucidating the molecular mechanism of this Ca-sensitive regulation. Here the structure of TnC within the thin filaments was investigated with neutron scattering, combined with selective deuteration and the contrast matching technique. Deuterated TnC was prepared, reconstituted into the native thin filaments, and neutron scattering patterns of these reconstituted thin filaments containing deuterated TnC were measured under the condition where non-deuterated components were rendered 'invisible' to neutrons. The obtained scattering curves arising only from deuterated TnC were analyzed by model calculations using the Monte Carlo method. The results showed that upon binding of Ca, radius of gyration of TnC changed from 23 AA to 24 AA , and the radial position of TnC within the thin filament changed from 53 AA to 49 AA .
Tanaka, Tadao; Yamaguchi, Tetsuji; Iida, Yoshihisa; Kimura, Yuichiro; Taki, Hiroshi; Fujiwara, Takeshi; Ueda, Masato*; Mukai, Masayuki; Yamada, Fumika; Mizuno, Tsuyoshi; et al.
no journal, ,
no abstracts in English
sensitization in the myofibrilsMatsumoto, Fumiko; Maeda, Kayo*; Nitanai, Yasushi*; Oda, Toshiro*; Maeda, Yuichiro*; Fujiwara, Satoru
no journal, ,
Familial hypertrophic cardiomyopathy (HMC) has been reported to be caused by mutations in a regulatory protein, troponin (Tn). HMC is characterized by functional aberration on the force-pCa relationship. Only a few cardiomyopathy-causing mutations have been mapped on the coiled-coil region (IT-arm) in the Tn core domain. Here we focus on two mutations in the IT-arm, E244D and K247R of TnT. Whereas E244D has been reported to show an increase of the maximum level of ATPase activity, the functional consequence of K247R mutation has not been analyzed. In order to understand how these mutations cause functional aberrations, we measured ATPase activity of myofibrils containing various mutants of these residues (E244; D, M, A, K and K247; R, E, A). The maximum level of ATPase activity was found to increase in K247R, without changing the Ca ion sensitivity, as found in E244D. A close inspection of the crystal structure showed that the side chains of E244 and K247 form the triplet with that of E110 of TnI on the outside of the hydrophobic core of the coiled-coil. This triplet is thus likely to introduce flexibility into the IT-arm at this position. The mutations at the residues 244 and 247 could alter this flexibility. The results obtained here suggested that the proper flexibility of the IT-arm is important for the correct function of the myofibrils. The relationship between the IT-arm flexibility and functional aberration in the myofibril will be discussed.
Suzuki, Masao*; Furusawa, Yoshiya*; Tsuruoka, Chizuru*; Kobayashi, Katsumi*; Usami, Noriko*; Maeda, Munetoshi*; Funayama, Tomoo; Sakashita, Tetsuya; Yokota, Yuichiro; Fukamoto, Kana; et al.
no journal, ,
no abstracts in English
Matsumoto, Fumiko; Maeda, Kayo*; Piroddi, N.*; Belus, A.*; Poggesi, C.*; Maeda, Yuichiro*; Fujiwara, Satoru
no journal, ,
Hypertrophic cardiomyopathy (HCM) is an autosomal dominant cardiac disease resulting from mutations in genes encoding contractile proteins, including troponin. HMC is characterized by functional aberration on the force-pCa relationship. Only a few HMC-causing mutations have been mapped on the coiled-coil region in the Tn core. Here we focus on two mutations in this region, E244D and K247R of TnT. Whereas E244D has been reported to show an increase of the maximum level of ATPase activity without changing the Ca sensitivity (Yanaga et. al., 1999), the functional consequence of K247R mutation has not been analyzed. We showed from the ATPase measurements of myofibrils containing the mutants K247R that this mutation exhibits similar functional consequences to the mutation E244D. Moreover, in order to understand how the mutations at these residues cause functional aberrations, we prepared various mutants of TnT (E244D, E244M, E244A, E244K, K247R, K247E, and K247A), having various volumes and charges, and measured ATPase activity of myofibrils containing these mutants TnT. The effect of mutations on the maximum ATPase activity level was different from each other while the Ca sensitivity was unchanged. To gain insight into the relationship between the ATPase activity and (possible) structural changes caused by these mutations, we carried out energy minimization/molecular dynamics calculations based on the crystal structure of the Tn-core. The results suggested that the stable hydrogen bond network at this region is important for the "proper" function of Tn.
Matsumoto, Fumiko; Piroddi, N.*; Belus, A.*; Scellini, B.*; Maeda, Kayo*; Tesi, C.*; Poggesi, C.*; Maeda, Yuichiro*; Fujiwara, Satoru
no journal, ,
We showed that two Hypertrophic Cardiomyopathy -associated mutations of TnT, E244D and K247R, increase the maximum ATPase activity without any change in Ca ion sensitivity in BSJ 2007. It is, however, still not clear if the mutations have direct effects on the muscle. We thus examined the maximal isometric tension and kinetics of Tn-exchanged myofibrils by use single myofibril. The results indicate that the effects of the mutations on the physiological function of the myofibrils are directly coupled with the effects on the ATPase activity. And the mutant TnT exchanged myofibrils had similar kinetics as the wild type.
Hayashi, Takehiro; Sasaki, Shinji; Mashiko, Shinichi; Yamagata, Ichiro; Ogawa, Ryuichiro; Inoue, Masaki; Yamashita, Shinichiro; Maeda, Koji
no journal, ,
no abstracts in English
Sekio, Yoshihiro; Yamagata, Ichiro; Yamashita, Shinichiro; Sasaki, Shinji; Ogawa, Ryuichiro; Mashiko, Shinichi; Hayashi, Takehiro; Inoue, Toshihiko; Inoue, Masaki; Maeda, Koji
no journal, ,
Corrosion and mechanical property tests utilizing spent fuel cladding made of zircaloy-2 were performed as a tentative test of the project for the purpose of simulating an environment at the very early stage after the accident in the SFP of unit 4 in the Fukushima Dai-ichi Nuclear Power Plant. The result of metallurgical investigation after corrosion test showed that no obvious changes in oxide film formed on the outer surface of cladding such as stripping occurred. In addition to that, the ring-tensile test results of samples after corrosion test was obtained and compared with that of samples before corrosion test, indicating that no significant degradation in mechanical property was confirmed. These results would have indicated that integrity of FAs was kept to be high as same as what it was before conducting corrosion test.
Shobu, Takahisa; Tominaga, Aki; Kisohara, Naoyuki; Maeda, Toshio*; Yamagishi, Ryuichiro*; Okihara, Shinichiro*; Tsuboi, Akihiko
no journal, ,
In this study, the internal defects and strain distribution in metal additive manufacturing and their changes by laser peening were evaluated. These studies using X-ray computed tomography and diffraction technique were carried out at BL22XU in synchrotron radiation facility SPring-8. As a result, it was confirmed that a large number of voids existed inside the additive manufacturing. However, almost no difference due to laser peening was confirmed. On the other hand, it was confirmed that the strain inside the additive manufacturing was almost
