National Institutes for Quantum and Radiological Science and Technology
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ダイヤモンドナノブリッジ共振器中のフォノンモードによるSiV中心の変調
No full textダイヤモンドPhC上にLN片をピックアンドプレイスしたデバイスに、MWを印加して機械振動を生成し、PhC内のSiV中心の光学遷移を変調したことについて発表する2025年度 量子情報関東・関西合同 Student Chapterconference poste
Survey of the international situation of education and training for industrial X-ray radiation workers
No full textIn May 2021, a big accident occurred in Japan in which radiation workers were exposed toindustrial X-ray. IAEA categorized this accident into Level 3 by the International Nuclear andRadiological Event Scale (INES).Considering the latest X-ray device conditions and accident examples, the Japanesegovernment has started to improve the national radiation control regulation for the use ofindustrial X-ray equipment. The authors are officially supporting this movement as an expertteam through their research.The targets of the governmental improvement are the structural standards for automaticwarning and safety devices of X-ray equipment, the duties of X-ray safety supervisors,education for X-ray radiation workers and supervisors, practical identification of controlledareas for X-ray equipment, and support for business operators and industry groups.The authors are now focusing on safety education for X-ray radiation workers and planned andcontinue questionnaire and interview surveys to know the domestic and international situationrelating to the stakeholders. The main purposes of our surveys are to know the system of safetyeducation and training on industrial X-rays in each country, and to know the way to manageindustrial X-ray irradiators for safety in each country.The contents of the questionnaire survey include regulations of X-ray, initial education andtraining for X-ray radiation workers, periodic education and training for X-ray radiation workers,X-ray safety supervisors without a national license, and international perspectives. We identifiedsome countries had unique situations and characteristics through our survey. We found severaldifferences depending on the country’s safety management history and culture:Log inTerms of usePrivacy policy© Fourwaves 2026, all rights reserved-Differences in the regulatory system and competent ministries for industrial X-ray equipment-Differences in the categorization of X-ray equipment-Differences in the requirements for initial and periodic education for X-ray workers-Differences in the management of students-Differences in the educational content-Differences in the requirements for X-ray safety supervisorsIn the presentation, the authors will introduce the current situation and plans for X-ray safetyeducation in Japan and share the latest results of our survey.We hope to discuss these topics with experts and stakeholders from various countries at thevenue8th International Symposium on the System of Radiological Protectionconference presentatio
A hidden property of the iron-sulfur protein in the mononuclear iron-bound state: species-dependent structural ordering induced by magnetic fields
No full textThe iron-sulfur (Fe-S) cluster assembly homolog 1 (ISCA1) is a ubiquitous protein conserved in various organisms. Previous work has shown that a pigeon ISCA1 (clISCA1) forms columnar oligomers in the 2Fe-2S cluster-bound state, the length of which has been known to change in response to magnetic fields. However, whether this unique property is conserved in ISCA1 proteins of other species, particularly humans (hsISCA1), is unclear. Moreover, a recent study revealed that clISCA1 binds to not only Fe-S clusters but also mononuclear iron atoms, which may impart some magnetic properties to clISCA1. In this study, the electron spin resonance revealed that hsISCA1 also binds to mononuclear iron atoms. Moreover, the magnetic responses of Fe-S cluster-unbound ISCA1s (Fe-ISCA1s), which bind only mononuclear iron atoms, were inspected by small-angle X-ray scattering analyses for pigeon (Fe-clISCA1) and human (Fe-hsISCA1). The results indicated that Fe-hsISCA1 formed columnar oligomers under geomagnetic conditions, whereas Fe-clISCA1 formed dumbbell-like oligomers. When a magnetic field (180 mT) was applied, the Fe-hsISCA1 oligomer was shortened within 1 min and gradually elongated again after 10 min. This result indicates that mononuclear iron atoms contribute to the magnetically induced structural ordering of ISCA1, whereas the contribution of the Fe-S clusters to the columnarization of ISCA1 varies among species. Although the physiological role of the magnetic properties of ISCA1 is not yet elucidated, this study demonstrated that the magnetic field responsiveness of ISCA1 is conserved in humans. The magnetic field responsiveness may be a hidden fundamental property of ISCA1 that is maintained even if the Fe-S cluster is released.journal articl
Spatiotemporal temperature control by holographic heating microscopy unveils cellular thermosensitive calcium signalling
No full textOptical microheating technologies have revealed how biological systems sense heating and cooling at the microscopic scale. Sensing is based on thermosensitive biochemical reactions that frequently engage membrane proteins, Ca2+ channels, and pumps to convert sensing information as the Ca2+ signalling in cells. These findings highlight the feasibility of thermally manipulating intracellular Ca2+ signalling. However, how the thermosensitive Ca2+ signalling would behave, particularly in multicellular systems, remains elusive. In this study, to extend the ability of the spatiotemporal temperature control by optical microheating technologies, we propose holographic heating microscopy. Water-absorbable infrared (IR) laser light is modulated by a reflective liquid crystal on a silicon spatial light modulator (LCOS-SLM). A computer-generated hologram displayed on the LCOS-SLM modulates the spatial phase pattern of the IR laser light to generate predesigned temperature gradients at the microscope focal plane. The holographic heating microscopy visualises how thermosensitive Ca2+ signalling is generated and propagated in MDCK cells, rat hippocampal neurons, and rat neonatal cardiomyocytes. Moreover, the optical control of the temporal temperature gradient reveals the cooling-rate dependency of Ca2+ signalling in HeLa cells. These findings demonstrate the extended ability of holographic heating microscopy in investigating cellular thermosensitivities and thermally manipulating cellular functions.journal articl
Ion irradiation induced microstructural development of polycrystalline double-thick-walled silicon carbide nanotubes
No full textIn this study, ion irradiation induced microstructural development of olycrystalline double-thick-walled (DTW) silicon carbide (SiC) nanotubes are investigated. In-situ transmission electron microscopy (TEM) observations of two kinds of olycrystalline DTW SiC nanotubes with a wide and narrow spacing between the outer and inner nanotubes are carried out under the ion irradiation with 200-keV Si+ ions at room temperature. The critical doses of amorphization for both DTW SiC nanotubes are larger than those of SiC bulk materials in the previous tudies. Amorphous DTW SiC nanotubes are successfully synthesized for the first time via the ion irradiation of both polycrystalline DTW SiC nanotubes. From in-situ TEM observation results, all of outer, inner diameters and length of both inner and outer nanotubes increase with increasing the irradiation dose till around complete amorphization of SiC crystals, and then decrease. After ion irradiation of more than 20 dpa, polycrystalline DTW SiC nanotubes with a wide and narrow spacing between the outer and inner nanotubes are transformed to amorphous SiC nanotube and SiC nanowire, respectively.journal articl
不足ドープ銅酸化物超伝導体における電荷励起
No full text不足ドープ域にある銅酸化物超伝導体La2-xSrxCuO4 (x = 0.075、0.12)について酸素K吸収端の共鳴非弾性Ｘ線散乱用いて電荷励起を観測し、その温度依存性を調べた。測定した波数の範囲では、明確な温度依存性は観測されなかった。当初目的とした強相関金属特有の電荷ダイナミクスにおけるスピンとの関係に関する議論を進めるためには、より広範かつ系統的なホール濃度、波数依存性の測定が必要である。journal articl
Thermal transport and confinement improvements with a high power and high energy neutral beam in JT-60U ELMy H-mode plasmas
No full textプラズマ中の高速イオンによる熱化プラズマの熱輸送の改善が、実験と理論の両方から報告されている。本研究では、JT-60において、より高いエネルギーを有する負イオン中性粒子ビーム（0.4 MeV）を入射した際のエネルギー閉じ込めと熱輸送特性を調べた。負イオン中性粒子ビームにより加熱パワーを増加させた際に、エネルギー閉じ込めの改善と、内部輸送障壁での熱輸送の改善（イオン温度勾配の増加）が見られた。journal articl
Supramolecular Conductive Hydrogels With Homogeneous Ionic and Electronic Transport
No full textMechanically resilient hydrogels with ion-electron mixed transport properties effectively bridge biology with electronics. An ideal bioelectronic interface can be realized through introducing electronically conductive polymers into supramolecular hydrogels. However, inhomogeneous morphologies of conducting polymers, such as poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), have limited mechanical properties and ion-electron interactions. Here, supramolecular conductive hydrogels that possess homogeneous ionic and electronic transport are achieved. The materials demonstrate high toughness (620 kJ m−3), stretchability (>1000%), softness (10.5 kPa), and conductivity (5.8 S cm−1), which surpasses commonly used inhomogeneous PEDOT:PSS-based hydrogels. The homogeneous network leads to higher charge injection capacitance and lower skin impedance compared to commercial electrodes or commonly used inhomogeneous PEDOT:PSS conducting networks. This significant advance arises from the homogeneous incorporation of the hydrophilic self-doped conducting polymer S-PEDOT, which has polymerized within a supramolecular polymer network template mediated by high-binding affinity host-guest crosslinks. Furthermore, the compatibility of S-PEDOT with hydrophilic secondary networks enables the realization of fully dryable and reswellable electronic devices, facilitating reusability and improving their ease of handling. It is anticipated that achieving such material architectures will offer a promising new direction in future synthesis and implementation of conductive hydrogels in the field of bioelectronics.journal articl
Trans-Scale Insights into Variability in Radiation Cancer Risk Across Tissues, Individuals, and Species
No full textDiversity is evident in various aspects of life and the human population. The current radiological protection system considers the diversity in disease susceptibility and incorporates some of it to provide a unified risk model for the human population. This paper focuses on variability in cancer risk among cells/tissues, individuals, and animal species. At the cell/tissue level, radiation cancer risk per unit dose varies among tissues, as indicated by epidemiological and animal studies. This variation is most likely due to the epigenetics of cells. At the individual level, radiation risks vary considerably depending on physiological, environmental, and genetic factors. At the species level, epidemiology is considered the most relevant source of radiological information, and limitations have been recognized in extrapolating animal data to human risks. A recent study demonstrated a fundamental relationship between cancer risk and somatic mutation rate in humans and mice. This relationship could lead to a new extrapolation method, which could be used to protect a wider range of species, including humans and other mammals. Thus, considering diversity in radiation cancer risk provides insight into the underlying aspects of radiobiology of radiological protection.journal articl
Environmental and biological drivers of 137Cs accumulation in freshwater fish across forested and downstream sites in Fukushima
No full textTo elucidate the ecological factors governing 137Cs accumulation in freshwater fish, we examined 10 species collected from forested headwater streams and downstream reaches of river systems flowing through the Fukushima evacuation zone. Fish collected from sites with higher forest cover in the upstream catchment exhibited consistently elevated 137Cs concentrations, indicatingthat forested environments serve as persistent sources of radiocesium to aquatic food webs more than a decade after the nuclear accident. Stable isotope analysis of δ13C further suggested that individuals assimilating more terrestrial-derived carbon tended to accumulate higher 137Cs levels. A positive relationship was also observed between relative body size, standardized within each species, and 137Cs concentration, suggesting that growth-related traits influence radiocesium accumulation. These results indicate that forest connectivity, dietary reliance on allochthonous resources, and individual growth characteristics jointly affect 137Cs accumulation in freshwater fish. In addition, migratory behavior may contribute to variation in 137Cs concentrations through shifts in foraging habitats and diet sources, as suggested for particular species. By integrating catchment-scale land cover data with individual isotopic and morphological indicators, our study clarifies the ecological mechanisms shaping radiocesium distribution across fish communities in post-accident environments. The approach and findings contribute to a broader understanding of long-term radiocesium dynamics in forested river networks and inform ecological risk assessment and fisheries management in radiologically impacted landscapes.journal articl