Multiple DNA damages induced by water radiolysis demonstrated using a dynamic Monte Carlo code

Kai, Takeshi; Toigawa, Tomohiro; Matsuya, Yusuke*; Hirata, Yuho; Tsuchida, Hidetsugu*; Ito, Yuma*; Yokoya, Akinari*

Communications Chemistry (Internet), 8, p.60_1 - 60_9, 2025/03

https://doi.org/10.1038/s42004-025-01453-x

Radiation DNA damage is formed from direct and indirect effects. The direct effect is the interaction between DNA and a radiation, while the indirect effect is the chemical reaction between DNA and radiolytic chemical species. We believed that when the direct effect is induced, multiple lesions are formed within 10 base pairs (about 3.4 nm) of DNA. The damage reduces repair efficiency and induces biological effects. In this study, DNA damage induced by only indirect effects was quantitatively evaluated. Our results indicated that the multiple damage is formed when only 10s of eV energy is deposited to water in the vicinity of DNA, although its formation probability is less than 1%. In other words, the possibility of late biological effects cannot be excluded simply by imparting energy to water in the extreme vicinity of DNA without direct interaction between radiation and DNA. Our results are one of the most important findings for understanding low-dose radiation risk.

Application of diffusive gradients in thin films (DGT) for the dynamic speciation of radioactive cesium in Fukushima Prefecture, Japan

Tanaka, Takuro*; Fukuoka, Masafumi*; Toda, Kanako*; Nakanishi, Takahiro; Terashima, Motoki; Fujiwara, Kenso; Niwano, Yuma*; Kato, Hiroaki*; Kobayashi, Natsuko*; Tanoi, Keitaro*; et al.

ACS ES&T Water (Internet), 4(8), p.3579 - 3586, 2024/08

https://doi.org/10.1021/acsestwater.4c00453

Heterogeneity effects in micro-beam XRF scanning spectroscopy of binary powdered mixtures and lake sediments

Katsuta, Nagayoshi*; Umemura, Ayako*; Naito, Sayuri*; Masuki, Yuma*; Itayama, Yui*; Niwa, Masakazu; Shirono, Shinichi*; Yoshida, Hidekazu*; Kawakami, Shinichi*

Spectrochimica Acta, Part B, 210, p.106817_1 - 106817_11, 2023/12

https://doi.org/10.1016/j.sab.2023.106817

X-ray fluorescence (XRF) scanning of lacustrine sediments has been used to extend the approach to a wider range of elemental records in both ages and timescales of variations in past environments and climates. However, one of severe problems with effects of the XRF intensity by grain size and mineralogical composition known as "heterogeneity effects" have been pointed out. This study investigated the heterogeneity effect of Fe intensities on X-ray beam using several binary powder mixtures and lacustrine sediment cores.

Identification of advanced spin-driven thermoelectric materials via interpretable machine learning

Iwasaki, Yuma*; Sawada, Ryoto*; Stanev, V.*; Ishida, Masahiko*; Kirihara, Akihiro*; Omori, Yasutomo*; Someya, Hiroko*; Takeuchi, Ichiro*; Saito, Eiji; Yorozu, Shinichi*

npj Computational Materials (Internet), 5, p.103_1 - 103_6, 2019/10

https://doi.org/10.1038/s41524-019-0241-9

Flexible heat-flow sensing sheets based on the longitudinal spin Seebeck effect using one-dimensional spin-current conducting films

Kirihara, Akihiro*; Kondo, Koichi*; Ishida, Masahiko*; Ihara, Kazuki*; Iwasaki, Yuma*; Someya, Hiroko*; Matsuba, Asuka*; Uchida, Kenichi*; Saito, Eiji; Yamamoto, Naoharu*; et al.

Scientific Reports (Internet), 6, p.23114_1 - 23114_7, 2016/03

https://doi.org/10.1038/srep23114

Heat-flow sensing is expected to be an important technological component of smart thermal management in the future. Conventionally, the thermoelectric (TE) conversion technique, which is based on the Seebeck effect, has been used to measure a heat flow by converting the flow into electric voltage. However, for ubiquitous heat-flow visualization, thin and flexible sensors with extremely low thermal resistance are highly desired. Recently, another type of TE effect, the longitudinal spin Seebeck effect (LSSE), has aroused great interest because the LSSE potentially offers favourable features for TE applications such as simple thin-film device structures. Here we demonstrate an LSSE-based flexible TE sheet that is especially suitable for a heat-flow sensing application. This TE sheet contained a NiZnFeO film which was formed on a flexible plastic sheet using a spray-coating method known as ferrite plating. The experimental results suggest that the ferrite-plated film, which has a columnar crystal structure aligned perpendicular to the film plane, functions as a unique one-dimensional spin- current conductor suitable for bendable LSSE-based sensors. This newly developed thin TE sheet may be attached to differently shaped heat sources without obstructing an innate heat flux, paving the way to versatile heat-flow measurements and management.

Origin of arsenic in paleo-dammed lake sediments of Ane River, central Japan, inferred from the stable isotope compositions

Masuki, Yuma*; Katsuta, Nagayoshi*; Niwa, Masakazu; Naito, Sayuri*; Yoshimizu, Chikage*; Tayasu, Ichiro*

no journal, , 

In this presentation, we report origin of high arsenic concentration in paleo-dammed lake sediments in Ane River, central Japan.

In vitro rejoining of enzymatically induced double-strand breaks in EGFP expressing plasmid DNA

Eda, Shuma*; Ito, Yuma*; Obata, Yui*; Hirose, Eri; Yokoya, Akinari*

no journal, , 

None

Masuno, Yuma*; Namie, Masanari; Saito, Junichi; Kim, J.-H.*; Yonezawa, Susumu*

no journal, , 

no abstracts in English