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Journal Articles

Discovery of a selective Cs$$^{+}$$ binding site of a $$beta$$-lactamase from the halophile by anomalous X-ray diffraction

Arai, Shigeki; Shibazaki, Chie; Shimizu, Rumi; Adachi, Motoyasu; Tamada, Taro; Tokunaga, Hiroko*; Ishibashi, Matsujiro*; Tokunaga, Masao*; Kuroki, Ryota

Kyushu Shinkurotoronko Kenkyu Senta Nempo, 2014, p.17 - 19, 2016/03

no abstracts in English

Journal Articles

Research of Takasaki Advanced Radiation Research Institute

Tamada, Masao

Genshiryoku Nenkan 2016, p.148 - 152, 2015/10

Takasaki Advanced Radiation Research Institute (TARRI) was established in April 1963. There are irradiation facilities of quantum beam such as ion, electron, Co-60 $$gamma$$-rays. TARRI has researched as complementary utilization together with other quantum beams such as neutron, synchrotron radiation, etc. as a part of the quantum beam platform. Recent technology transfer are outcomes of mutation-breeding sake yeast for quality sake brewed from the finest rice and cesium removal adsorbent for cartridge-type filters. Radiation-induced crosslinked resin was commercialized recently as a school teaching material. Dissemination of radiation technology has been continued through outreach activities.

Journal Articles

Radiation processing in my research life

Tamada, Masao

Hoshasen Kagaku (Internet), (100), P. 16, 2015/10

Collection of a rare metal form hot spring water attracted medias and had a public response by reports of numerous newspapers and television programs in my 35 years' research and development of radiation processing technologies and its technology management. Collection experiments of the rare metal were carried out in Kusatsu Onsen, Gunma prefecture, where discharge of hot spring water is the largest in Japan. We were on standby 6 am there when morning live broadcast started from 8 am. The invention of emersion grafting solved the problems in the cost reduction of adsorbent production owing to its high grafting yield and led the way for technology transfer of filter for the removal of metal ions in ppb level from semiconductor cleaning liquid and adsorbent for radio-active cesium.

Journal Articles

Promotion of cooperation for innovation

Tamada, Masao

Tokushima Daigaku Rikogakubu 100 Nenshi, p.454 - 455, 2015/10

Department of engineering, Gunma University in Kiryu city inherited plenty of expertise and experts in the research area of polymer chemistry from its historical background since the predecessor town of Kiryu city prospered in the trade and production of silk. Research cooperation and personnel exchanges between department of engineering, Gunma University and Takasaki advanced radiation research institute, Japan Atomic Energy Agency played important roles in the discovery of unknown phenomena, the clarification of mechanism, the creation of innovation and the human resource development in wide range of generations. The further cooperation with dense relationship will build the most advanced technology and novel industrial applications.

Journal Articles

Structure of a highly acidic $$beta$$-lactamase from the moderate halophile ${it Chromohalobacter}$ sp.560 and the discovery of a Cs$$^{+}$$-selective binding site

Arai, Shigeki; Yonezawa, Yasushi*; Okazaki, Nobuo*; Matsumoto, Fumiko*; Shibazaki, Chie; Shimizu, Rumi; Yamada, Mitsugu*; Adachi, Motoyasu; Tamada, Taro; Kawamoto, Masahide*; et al.

Acta Crystallographica Section D, 71(3), p.541 - 554, 2015/03

 Times Cited Count:7 Percentile:50.76(Biochemical Research Methods)

The crystal structure of halophilic $$beta$$-lactamase from ${it Chromohalobacter}$ sp.560 (HaBLA) was determined using X-ray crystallography. Moreover, the locations of bound Sr$$^{2+}$$ and Cs$$^{+}$$ ions were identified by anomalous X-ray diffraction. The location of one Cs$$^{+}$$ specific binding site was identified on HaBLA even in the presence of 9-fold molar excess of Na$$^{+}$$ (90 mM Na$$^{+}$$ /10 mM Cs$$^{+}$$). This Cs$$^{+}$$ binding site is formed by two main-chain O atoms and an aromatic ring of a side chain of Trp. An aromatic ring of Trp interacts with Cs$$^{+}$$ by the cation-$$pi$$ interaction. The observation of a selective and high-affinity Cs$$^{+}$$ binding site provides important information that is useful for designing artificial Cs$$^{+}$$ binding sites useful in bioremediation of radioactive isotopes.

Journal Articles

Uranium in seawater

Tamada, Masao

Genshiryoku, Ryoshi, Kakuyugo Jiten, 3, p.152 - 153, 2014/12

One ton of seawater contains 3.3 mg uranium. Total weight of the uranium in seawater is 4.5 billion tons which equals 75,000 times of annual uranium consumption in the nuclear plant all over the world. The uranium adsorbent with high mechanical strength has been successfully synthesized by radiation-induced graft polymerization. This uranium adsorbent was evaluated in the sea areas of Aomori and Okinawa, Japan. At Aomori, 1 kg uranium as yellow cake was collected by soaking the adsorbent cloths. To reduce the recovery cost, a braid type adsorbent was developed. By using new braid type adsorbent, 1.5 g-U/(kg-adsorbent) was achieved after 30 days' soaking in Okinawa. The attainable cost is estimated at 25,000 yen/kg-U.

Journal Articles

Structural characteristics of alkaline phosphatase from the moderately halophilic bacterium ${it Halomonas}$ sp.593

Arai, Shigeki; Yonezawa, Yasushi*; Ishibashi, Matsujiro*; Matsumoto, Fumiko*; Adachi, Motoyasu; Tamada, Taro; Tokunaga, Hiroko*; Blaber, M.; Tokunaga, Masao*; Kuroki, Ryota

Acta Crystallographica Section D, 70(3), p.811 - 820, 2014/03

 Times Cited Count:12 Percentile:63.07(Biochemical Research Methods)

In order to clarify the structural basis of halophilic characteristics of an alkaline phosphatase derived from the moderate halophile ${it Halomonas}$ sp.593 (HaAP), the tertiary structure of HaAP was determined to 2.1${AA}$ resolution by X-ray crystallography. Structural properties of surface negative charge and core hydrophobicity are shown to be intermediate between halophile and non-halophile characteristics, and may explain the unique functional adaptation to a wide-range of salt concentration.

Journal Articles

Present and future of R&D on radiation processing of polymers

Tamada, Masao

Hoshasen To Sangyo, (135), p.4 - 5, 2013/12

Polymer materials are available in body of electric appliance as well as versatile applications as functional polymers. There are radiation-induced graft polymerization and crosslinking as radiation processing technologies for functionalization of existing polymers. Radiation processing of polymers has big potential for the creation of new seeds which cannot be achieved with conventional chemical techniques. It is important for us to collect information on the originating seeds and the related needs, and to explore the industrial outputs quickly and accurately with collaborative work between users and experts.

Journal Articles

Preparation of polymer gel dosimeters based on less toxic monomers and gellan gum

Hiroki, Akihiro; Sato, Yuichi*; Nagasawa, Naotsugu; Ota, Akio*; Seito, Hajime; Yamabayashi, Hisamichi*; Yamamoto, Takayoshi*; Taguchi, Mitsumasa; Tamada, Masao; Kojima, Takuji

Physics in Medicine & Biology, 58(20), p.7131 - 7141, 2013/10

 Times Cited Count:17 Percentile:54.54(Engineering, Biomedical)

Journal Articles

Radiation processing using quantum beams

Tamada, Masao

Hoshasen Kagaku (Internet), (96), P. 1, 2013/09

Innovations in scientific technology are expected to revive the Japanese economy. Advantages of quantum beam technology are to be able to develop materials which have novel properties and superior functionality to those achieved by chemical methods. Such materials are favorable for technology transfer since they have higher potential than conventional products. This point is advantageous in quantum beam technology. Hence, it is extremely important that research and development of both new technology of quantum beams and new seeds aiming at industrial applications.

Journal Articles

Recovery of uranium from seawater

Tamada, Masao

Tokoton Yasashii Ion Kokan No Hon, p.130 - 131, 2013/06

One ton of seawater contains 3.3 mg uranium. Total weight of the uranium in seawater is 4.5 billion tons which equals 1,000 times of uranium in available uranium ore all over the world. The uranium adsorbent with high strength has been successfully synthesized by radiation-induced graft polymerization. This uranium adsorbent was evaluated in the sea areas of Aomori and Okinawa in Japan. At the sea area of Aomori, 1kg uranium as yellow cake was collected by ocean experiment. To reduce the recovery cost, a braid type adsorbent was developed. This new adsorbent realized 1.5g-U/(kg-adsorbent) in Okinawa. The practical technology of uranium recovery from seawater is expected since there is no big difference in the uranium costs from seawater and mine.

Journal Articles

Effect of partial delignification of kenaf bast fibers for radiation graft copolymerization

Mohamed, N. H.*; Tamada, Masao; Ueki, Yuji; Seko, Noriaki

Journal of Applied Polymer Science, 127(4), p.2891 - 2895, 2013/02

 Times Cited Count:13 Percentile:37.82(Polymer Science)

Changes in residual lignin of kenaf bast fiber with acidic chlorite using various parameters were conducted to produce partial delignified fiber for radiation graft copolymerization. The effect of delignification temperature, operating time as well as chlorite doses on the residual lignin of the fibers has been reported. Results obtained indicated that the optimal delignification was achieved at 80$$^{circ}$$C for 6h with 0.5% chlorite. The reduction in density, size and tensile strength were attributed to the increase of removal of lignin from the fiber. Radiation induced emulsion graft copolymerization of 4-chloromethyl styrene (CMS) on partial delignified kenaf with residual lignin $$<$$2% resulted in higher degree of grafting of about 143% as compared to the undelignified fiber, which showed the absence of grafting degree.

Journal Articles

Pb(II) adsorption performance of fibrous graft adsorbent having phosphate groups

Ueki, Yuji; Dafader, N. C.*; Seko, Noriaki; Tamada, Masao

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 41, 2013/01

no abstracts in English

Journal Articles

Emulsion graft polymerization of 4-chloromethylstyrene on kenaf fiber by pre-irradiation method

Mohamed, N. H.*; Tamada, Masao; Ueki, Yuji; Seko, Noriaki

Radiation Physics and Chemistry, 82, p.63 - 68, 2013/01

 Times Cited Count:12 Percentile:67.14(Chemistry, Physical)

no abstracts in English

Journal Articles

Development of soil amendment by radiation processing and its application to sandy soil

Inoue, Mitsuhiro*; Nagasawa, Naotsugu; Tamada, Masao

Nohon Sakyu Gakkai-Shi, 59(2), p.61 - 70, 2012/11

no abstracts in English

Journal Articles

Metal adsorbent for alkaline etching aqua solutions of Si wafer

Tamada, Masao; Ueki, Yuji; Seko, Noriaki; Takeda, Toshihide*; Kawano, Shinichi*

Radiation Physics and Chemistry, 81(8), p.971 - 974, 2012/08

 Times Cited Count:7 Percentile:48.31(Chemistry, Physical)

In the fabrication process of semiconductor, Si wafer surface is etched by strong-alkaline aqua solutions such as 48 % NaOH and KOH. If the etchant is contaminated by Ni and Cu, smalls pits which appeared on Si surface in the process of surface polishing caused poor production yield of the Si wafers. Available commodity adsorbent resins shrink in the high concentration of alkaline aqua solutions and bias flow occurred in the case of their column packing. Hence, novel fibrous adsorbent was synthesized by radiation-induce graft polymerization on nonwoven materials composed of pure polyethylene fibers. The obtained fibrous adsorbent module (TM: Metolate) had practical cost and performance that flow rate is ten times and effective capacity is some tens times higher than commercialized adsorbent resins and fibers.

Journal Articles

Study and optimization on graft polymerization under normal pressure and air atmospheric conditions, and its application to metal adsorbent

Ueki, Yuji; Dafader, N. C.*; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

Radiation Physics and Chemistry, 81(7), p.889 - 898, 2012/07

 Times Cited Count:9 Percentile:56.92(Chemistry, Physical)

Journal Articles

R&D for graft adsorbents by radiation processing

Seko, Noriaki; Tamada, Masao

Nihon Ion Kokan Gakkai-Shi, 23(2), p.51 - 58, 2012/05

no abstracts in English

Journal Articles

A Structural mechanism for dimeric to tetrameric oligomer conversion in ${it Halomonas}$ sp. nucleoside diphosphate kinase

Arai, Shigeki; Yonezawa, Yasushi; Okazaki, Nobuo; Matsumoto, Fumiko; Tamada, Taro; Tokunaga, Hiroko*; Ishibashi, Matsujiro*; Blaber, M.; Tokunaga, Masao*; Kuroki, Ryota

Protein Science, 21(4), p.498 - 510, 2012/04

 Times Cited Count:14 Percentile:34.5(Biochemistry & Molecular Biology)

In order to clarify the oligomer state of nucleoside diphosphate kinase (NDK) from moderately halophilic ${it Halomonas}$ sp. 593 (HaNDK), the crystal structure of HaNDK was determined by X-ray crystallography. The crystal structures of the wild-type HaNDK and the mutant HaNDK (E134A) showed a dimer and a tetramer, respectively. The higher ordered association of proteins usually contributes to an increase in thermal stability and substrate affinity. The change in the assembly form by a minimum mutation may be an effective way for NDK to acquire molecular characteristics suited to various circumstances.

Journal Articles

Surface modification of vulcanized rubber by radiation grafting, 2; Improvement in performance of wiper rubber

Mizote, Norihito*; Katakai, Akio; Tamada, Masao

Journal of Applied Polymer Science, 123(4), p.2172 - 2176, 2012/02

 Times Cited Count:5 Percentile:16.89(Polymer Science)

Surface of natural rubber was modified by radiation-induced grafting of 2-hydroxyethyl methacrylate (HEMA) to improve the properties of surface hardness, dry friction, wiping performance, and wear duration. The composition ration of HEMA to rubber was controlled from 0.29 to 0.93 by changing HEMA concentration and dose in graft polymerization. When this composition ration was higher than 0.7, the surface hardness was higher than 64 and the coefficient of dry friction lower than 0.65. Those values became better than those of commercially available chlorinated-rubber in terms of wear and friction against glass. The resulting wear resistance was 10 times higher than chlorinated rubber. However, the surface hardness in wet state was 62.5 since grafted-HEMA gave the hydrophilicity to the rubber. As a result, the grafted-HEMA rubber realized 95% and higher wiping performance of water on glass.

451 (Records 1-20 displayed on this page)