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Journal Articles

Design for detecting recycling muon after muon-catalyzed fusion reaction in solid hydrogen isotope target

Okutsu, Kenichi*; Yamashita, Takuma*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 170, p.112712_1 - 112712_4, 2021/09

A muonic molecule which consists of two hydrogen isotope nuclei (deuteron (d) or tritium (t)) and a muon decays immediately via nuclear fusion and the muon will be released as a recycling muon, and start to find another hydrogen isotope nucleus. The reaction cycle continues until the muon ends up its lifetime of 2.2 $$mu$$s. Since the muon does not participate in the nuclear reaction, the reaction is so called a muon catalyzed fusion ($$mu$$CF). The recycling muon has a particular kinetic energy (KE) of the muon molecular orbital when the nuclear reaction occurs. Since the KE is based on the unified atom limit where distance between two nuclei is zero. A precise few-body calculation estimating KE distribution (KED) is also in progress, which could be compared with the experimental results. In the present work, we observed recycling muons after $$mu$$CF reaction.

Journal Articles

Time evolution calculation of muon catalysed fusion; Emission of recycling muons from a two-layer hydrogen film

Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

Fusion Engineering and Design, 169, p.112580_1 - 112580_5, 2021/08

A muon ($$mu$$) having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion between deuteron (d) and triton (t). These two nuclei are bound by $$mu$$ and form a muonic hydrogen molecular ion, dt$$mu$$. Due to the short inter-nuclear distance of dt$$mu$$, the nuclear fusion, d +t$$rightarrow alpha$$ + n + 17.6 MeV, occurs inside the molecule. This reaction is called muon catalyzed fusion ($$mu$$CF). Recently, the interest on $$mu$$CF is renewed from the viewpoint of applications, such as a source of high-resolution muon beam and mono-energetic neutron beam. In this work, we report a time evolution calculation of $$mu$$CF in a two-layered hydrogen isotope target.

Journal Articles

Interaction of double-stranded DNA with polymerized PprA protein from ${it Deinococcus radiodurans}$

Adachi, Motoyasu; Hirayama, Hiroshi; Shimizu, Rumi; Sato, Katsuya; Narumi, Issey*; Kuroki, Ryota

Protein Science, 23(10), p.1349 - 1358, 2014/10

 Times Cited Count:9 Percentile:31.87(Biochemistry & Molecular Biology)

Pleiotropic protein promoting DNA repair A (PprA) is a key protein that facilitates the extreme radioresistance of ${it Deinococcus radiodurans}$. To clarify the role of PprA in the radioresistance mechanism, the interaction between recombinant PprA expressed in Escherichia coli with several double-stranded DNAs was investigated. In a gel-shift assay, the band shift of supercoiled pUC19 DNA caused by the binding of PprA showed a bimodal distribution, which was promoted by the addition of 1 mM Mg, Ca, or Sr ions. The dissociation constant of the PprA-supercoiled pUC19 DNA complex, calculated from the relative portions of shifted bands, was 0.6 $$mu$$M with a Hill coefficient of 3.3 in the presence of 1 mM Mg acetate. This indicates that at least 281 PprA molecules are required to saturate a supercoiled pUC19 DNA, which is consistent with the number of bound PprA molecules estimated by the UV absorption of the PprA-pUC19 complex purified by gel filtration. This saturation also suggests linear polymerization of PprA along the dsDNA. On the other hand, the bands of linear dsDNA and nicked circular dsDNA that eventually formed PprA complexes did not saturate, but created larger molecular complexes when the PprA concentration was greater than 1.3 $$mu$$M. This result implies that DNA-bound PprA aids association of the termini of damaged DNAs, which is regulated by the concentration of PprA.

Journal Articles

In-situ XAFS analysis of Y zeolite-supported Rh catalysts during high-pressure hydrogenation of CO$$_{2}$$

Bando, Kyoko*; Saito, Takeru; Sato, Koichi*; Tanaka, Tomoaki*; Dumeignil, F.*; Imamura, Motoyasu*; Matsubayashi, Nobuyuki*; Shimada, Hiromichi*

Topics in Catalysis, 18(1-2), p.59 - 65, 2002/01

no abstracts in English

Oral presentation

Analyses of DNA complex and crystallization of the DNA repair promoting protein PprA derived from Deinococcus Radiodurance

Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya*; Narumi, Issei; Kuroki, Ryota

no journal, , 

The resistance of Deinococcus radiodurans to $$gamma$$-ray is 1000 times higher than that of human cells. PprA is the novel protein which promotes repairing DNA, and play a key role in the ability to resist to the radiation. The characterization of PprA have showed: (1) that the expression of PprA is controlled under another novel protein of PprI (2) that PprA promotes ligase reaction: (3) that pprA exhibits the ability to bind on DNA. In this study, our objective is the crystal structure analysis of PprA to reveal its structure-function relationships and for application as genetic and clinical tools. Here, we constructed the E. coli expression and purification system of PprA. Using the purified PprA, some small crystals in size were obtained after screening of conditions for crystalization. Beased on the analyses of DNA-PprA interaction, we showed that 280 molecules of PprA at least can bind on a DNA molecule of pUC19 plasmid (2686bp). In addition, we indicated that several DNA-PprA complexes may form higher complex, when DNA includes terminal end or nick (the cleaved part on a DNA strand). These results are important knowledge in molecular assembly and function of PprA.

Oral presentation

Analyses on interactions of DNA with the novel DNA repairing protein of PprA derived from Deinococcus radiodurans

Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya; Yura, Kei; Narumi, Issei; Kuroki, Ryota

no journal, , 

Deinococcus radiodurans exhibits 1000 times higher radiation resistance than human cells. PprA is cloned from the bacteria and the novel DNA repair protein that plays an important role in the resistance. This study is aimed to reveal the structure function relationship of PprA. The recombinant PprA protein was purified from E. coli. The interactions of PprA with DNA were analyzed by gel shift assay and gel filtration. The results showed that (1) at least 280 molecules of PprA can bound to a DNA molecule of pUC19 composed of 2686bp (2) the formation the complex of PprA and DNA depends on Mg, Ca and Sr ions at low concentration (3) the formation the complex of PprA and DNA depends on the concentration of the salt at the range of 0 to 0.4M sodium acetate. In addition, the result indicated that the complexes of PprA and DNA can form larger complex depending on the concentration of PprA molecule, when using linear double stranded DNA. This suggests that PprA may locate two terminals of a DNA molecule damaged by radiation at near distance for DNA repairing.

Oral presentation

Analyses in interaction between DNA and PprA of the novel DNA repair protein derived from Deinococcus radiodurans

Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya; Yura, Kei; Narumi, Issei; Kuroki, Ryota

no journal, , 

no abstracts in English

Oral presentation

Analysis on interactions of DNA with the novel DNA repairing protein PprA derived from Deinococcus radiodurans

Adachi, Motoyasu; Tamada, Taro; Sato, Katsuya; Yura, Kei; Narumi, Issei; Kuroki, Ryota

no journal, , 

PprA is cloned from the bacteria and the novel DNA repair protein that plays an important role in the resistance. This study is aimed to reveal the structure function relationship of PprA. The recombinant PprA protein was purified from E. coli. The interactions of PprA with DNA were analyzed by gel shift assay and gel filtration. The results showed that (1) at least 280 molecules of PprA can bound to a DNA molecule of pUC19 composed of 2686bp (2) the formation the complex of PprA and DNA depends on Mg, Ca and Sr ions at low concentration (3) the formation the complex of PprA and DNA depends on the concentration of the salt at the range of 0 to 0.4M sodium acetate. In addition, the result indicated that the complexes of PprA and DNA can form larger complex depending on the concentration of PprA molecule, when using linear double stranded DNA. This suggests that PprA may locate two terminals of a DNA molecule damaged by radiation at near distance for DNA repairing.

Oral presentation

Structural and functional analysis of PprA from Deinococcus radiodurans

Yamada, Mitsugu; Adachi, Motoyasu; Sato, Katsuya; Tamada, Taro; Yura, Kei*; Kuroki, Ryota; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

Thermodynamic interaction between cold shock protein from extreme thermophile and single stranded DNA and the three-dimensional structure of their complex

Yoshimura, Naoki*; Sato, Rena*; Adachi, Motoyasu; Kuroki, Ryota; Kato, Etsuko*; Kidokoro, Shunichi*

no journal, , 

The change of the thermodynamic functions accompanying the binding of a single stranded oligo-DNA with a sequence of TCTTTTT to cold shock protein from ${it Thermus thermophiles}$ HB8 was evaluated by isothermal titration calorimetry, and the three-dimensional structure of the complex was determined by X-ray crystallography. The binding was almost approximated by a two-state model and found to be stabilized by large negative enthalpy change due to the stacking interaction between the bases of the DNA and the aromatic side chains of the protein.

Oral presentation

Time evolution calculation of muon catalyzed fusion by the Runge-Kutta method

Yamashita, Takuma*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

A muon ($$mu$$) having 207 times larger mass of electron and the same charge as the electron has been known to catalyze a nuclear fusion ($$mu$$CF) between deuteron (d) and triton (t). In this work, we have solved simultaneous reaction rate equations by the 4th-order Runge-Kutta method for the jointed $$mu$$CF cycles in the two layers (H$$_{2}$$/D$$_{2}$$ and D$$_{2}$$/T$$_{2}$$). The T$$_{2}$$ concentration to maximize the intensities of fusion neutrons and muons emitted to the vacuum will be discussed.

Oral presentation

Detection of neutron detection of dd-$$mu$$CF experiment at J-PARC MLF

Natori, Hiroaki*; Doiuchi, Shogo*; Ishida, Katsuhiko*; Kino, Yasushi*; Miyake, Yasuhiro*; Miyashita, Konan*; Nakashima, Ryota*; Nagatani, Yukinori*; Nishimura, Shoichiro*; Oka, Toshitaka; et al.

no journal, , 

A muonic molecule which consists of muon and two hydrogen isotope nuclei (deuteron (d) or tritium (t)) decays immediately via nuclear fusion ($$mu$$CF) and the muon will be released as a recycling muon. We attempted to use these muons to develop the scanning muon microscope. In this work, we will report the detection of neutron which emits during the $$mu$$CF reaction.

Oral presentation

Observation of released muon after intramolecular nuclear reaction, 1; Development of detection method using muonic X-ray

Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

Muon catalized fusion ($$mu$$CF) is expected to be a high-quality muon beam source for undestructive measurement and a monoenergetic neutron source. In this work, we attemped to observe a released muon after intermolecular nuclear reaction using muonic X-ray.

Oral presentation

Observation of released muon using muonic X-ray in dd-$$mu$$CF experiment at J-PARC MLF

Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

Muon catalized fusion ($$mu$$CF) is expected to be a high-quality muon beam source for undestructive measurement and a monoenergetic neutron source. In this work, we discussed how to observe a kinetic energy distribution of a recycling muon emitted after $$mu$$CF reaction.

Oral presentation

Observation of released muon after intermolecular nuclear reaction, 2; Transport simulation of particles

Miyashita, Konan*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

To observe a kinetic energy distribution of a recycling muon emitted after $$mu$$CF reaction, it is necessary to guide the recycling muons to a detector. In this work, we simulated the muon transportation using PHITS code and designed an experimental system.

Oral presentation

Observation of released muon after intramolecular nuclear reaction, 3; Electric field design

Nakashima, Ryota*; Okutsu, Kenichi*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

The recycling muon emitted after the muon catalized fusion ($$mu$$CF) has a kinetic energy between a few keV to 10 keV. To observed the kinetic energy distribution of the recycling muon, we have to guide and inject muons to Ti foil, and measure the muonic X-ray. In this work, we utilized SIMION code to calculate the electric field and the trajectory of muons from deuteron target to Ti foil.

Oral presentation

Numerical simulation and design for momentum distribution measurement of muon released from muon-catalyzed fusion

Miyashita, Konan*; Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

To measure the kinetic energy of a recycling muon, we discussed how to reduce the background radiation and the trajectory of the transported recycling muons by simulation code.

Oral presentation

Particle transport simulation of kinetic energy selection and detection of muon after muon catalyzed fusion reaction

Nakashima, Ryota*; Okutsu, Kenichi*; Kino, Yasushi*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

To detect a recycling muon emitted after muon catalyzed fusion reaction, it is necessary to guide the recycling muons from the target to a detector in a low background area. In this work, we simulated the muon transportation using SIMONS and PHITS codes and designed an experimental system.

Oral presentation

Development of muon detecting system for revealing muon catalyzed fusion elementary processes

Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

A muon is one of elementary particles which is known to weight 207 times more than an electron. A nuclear fusion reaction occurs in a muonic molecule which consists of two hydrogen isotope nuclei and a muon because the muon binds more tightly than electron. Since the muon does not directly participate in the fusion reaction, the reaction is called muon catalyzed fusion ($$mu$$CF). The muon released after the reaction is called a "recycling muon", and maintains the molecular orbital information when the muonic molecule formed. Therefore, information of the muon wavefunction can be investigated by observing the energy distribution of the recycling muon. We will report the experimental setup for measuring the energy distribution of the recycling muons after the nuclear reaction.

Oral presentation

Solid hydrogen target for muon catalyzed fusion elementary process measurement

Okutsu, Kenichi*; Kino, Yasushi*; Nakashima, Ryota*; Miyashita, Konan*; Yasuda, Kazuhiro*; Yamashita, Takuma*; Okada, Shinji*; Sato, Motoyasu*; Oka, Toshitaka; Kawamura, Naritoshi*; et al.

no journal, , 

Muon catalyzed fusion ($$mu$$CF) is a cyclic reaction where a negatively charged muon itself acts like a catalyst of nuclear fusion between hydrogen isotopes, such as $$mathrm{dd}mu rightarrow {}^{3}mathrm{He} + mathrm{n} + mu + 3.27~mathrm{MeV}$$ or $$mathrm{t} + mathrm{p} + mu + 4.03~mathrm{MeV}$$. In this work, we have investigated the shape and characteristic of solid hydrogen isotope target.

22 (Records 1-20 displayed on this page)