National Institutes for Quantum and Radiological Science and Technology
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Resonant inelastic x-ray scattering reveals spin flipping mediated by copper-amino acid interaction
No full text本研究では、共鳴非弾性X線散乱を用いて、銅アミノ酸錯体がもつ不対電子スピンにおけるスピン反転の観察について発表を行う。第39回日本放射光学会年会・放射光科学合同シンポジウムconference poste
Soft x-ray high harmonic generation using an infrared light source and its application to the measurements of x-ray absorption near-edge structure at the oxygen K edge
No full textWe demonstrate high harmonic generation beyond the water window using an intense infrared light source operating at 2000 nm in lithium niobate-based optical parametric chirped-pulse amplification by using an Yb:YAG thin-disk laser as a pump. The output pulses from the parametric amplifier (pulse energy: 1.68 mJ, wavelength: 1750–2500 nm, repetition rate: 5 kHz) are temporally compressed with an efficiency of 79% (1.32-mJ compressed pulse) down to 19.5 fs, which corresponds to the 2.9-cycle duration. The generated soft x-ray harmonics have been employed to measure x-ray absorption near-edge structure around the K edges of carbon, nitrogen, and oxygen, with acquisition times short enough to enable practical applications in time-resolved soft x-ray spectroscopy.journal articl
Dichloromethane decomposition by electron beam under nitrogen, oxygen, and a mixture of nitrogen and oxygen atmospheres
No full textGaseous dichloromethane was irradiated with an electron beam under nitrogen, oxygen, and a mixture of nitrogen and oxygen atmospheres with and without moisture. Experiments using radical scavengers of N2O and cyclohexene showed that the dominant active species that decompose dichloromethane differ depending on the atmosphere. Under dry conditions, N atoms and O2- produced by the irradiation of nitrogen and oxygen oxidize dichloromethane. When moisture is present, the decomposition of dichloromethane by N atoms and O2- is inhibited and OH radicals produced by the irradiation of water decompose dichloromethane. Required absorbed dose for the dichloromethane decomposition strongly depends on the atmospherejournal articl
Reflection Soft X-ray Fine Structure Spectroscopy Using an Ultrashort Laser-based Light Source
No full textWe present reflection measurements performed with a compact soft X-ray light source based on high-order harmonic generation, driven by an intense optical parametric chirped pulse amplifier operating at a central wavelength of 2000 nm and a repetition rate of 5 kHz.レーザー学会学術講演会第46回年次大会conference presentatio
BLOC: Buildable and Linkable Organ on a Chip
No full textPreclinical drug testing in animals is costly, raises ethical concerns, and often fails to predict human responses, highlighting the need for alternatives. Microphysiological systems (MPSs) have emerged as alternatives to animal experiments in physiology and drug development. However, conventional MPSs are designed for specific applications and lack versatility and scalability, limiting broader adoption. In this study, we developed a “Buildable and Linkable Organ on a Chip” (BLOC) that enables flexible construction of diverse MPS configurations. In this system, Culture, Control, and Analysis BLOCs have been standardized to the same size and linked using inlet/outlet joints for perfusion. Radiation-induced chemical reactions are used to suppress the adsorption and absorption of small hydrophobic molecules by BLOCs composed of polydimethylsiloxane. BLOCs for 2D/3D culture can also encapsulate radiation-crosslinked protein hydrogels with designed stiffness and microtopography to mimic the microenvironment in vivo. A perfusion device connecting Culture BLOCs is designed for a toxicity assay mimicking systemic circulation using six types of organoids. An automatic enzyme-linked immunosorbent assay device connecting Culture, Control, and Analysis BLOCs detects proteins released from organoids. BLOCs, which users can freely configure to suit their needs, are expected to emerge as powerful tools in basic research and preclinical trials using MPSs.journal articl
Integration of Active Personal Dosimeters, Videos from In-Room Monitors, and Videos from the Surgeon’s Main Panel Reveal Pitfalls in Radiation Protection
No full textWe examined whether synchronizing and analyzing three data sources, active personal dosimeter (APD) information, in-room monitoring camera footage, and the operator’s main angiography panel video, could identify opportunities to reduce occupational radiation exposure during cerebral angiography without therapeutic intervention. We analyzed the behavior of eight physicians and radiation doses measured outside the lead apron during 12 diagnostic cerebral angiography procedures performed between January and April 2024. Appropriate use of a ceiling-suspended radiation protective shield (CSRPS) was associated with approximately 70% exposure reduction. In addition, exposure during femoral arteriography (catheter advancement from femoral artery puncture to the aortic arch) accounted for approximately 50% of the total exposure, identifying both as effective intervention points. This approach identified operators’ incorrect use of radiation protection equipment and enabled clear feedback to operators on areas for improvements in radiation protection practices.journal articl
レーザープラズマにおける原子過程・量子プロセス
No full textレーザー駆動金イオン加速における電離・加速プロセスの紹介を通して、レーザープラズマ科学に関連する量子プロセスや原子過程について概観する。2025年度学際的量子プロセス研究会conference presentatio
Coherent Transverse Oscillation of Coulomb Crystals in a Linear Paul Trap
No full textA Coulomb crystal formed in a linear Paul trap by Doppler cooling with a single axial laser often shows undesired oscillatory behavior in the direction perpendicular to the trap axis. This transverse oscillation is found to include two distinct coherent motions; in addition to the well-known micromotion driven by external error fields, there exists another natural oscillatory component. The latter oscillation is a kind of statistical phenomenon that takes place even in the absence of any mechanical errors. A detailed theoretical study is performed to clarify the basic characteristics of these overlapping coherent motions. A simple cooling scheme is proposed to minimize the transverse oscillation amplitude of a Coulomb crystal without use of extra lasers. The validity of theoretical predictions made in the present paper is confirmed through molecular dynamics simulations assuming the three-dimensional electrode geometry of a typical Paul trap.journal articl
Quantifying upright positioning accuracy with optical surface tracking in radiotherapy
No full textPurpose: This study quantified inter- and intra-fractional setup accuracies in the upright posture and compared them among setups with different immobilization methods.Methods: Two and four setups were examined for abdominal and head and neck (HN) cancer treatments, respectively. Fifteen asymptomatic volunteers were positioned to a replicated chair of an upright radiotherapy platform with leg immobilization devices, backrest attachments, thermoplastic masks, and vacuum cushions. The 3D positions of the subject body and masks were monitored by calculating 3D point clouds of 26 surface markers from three camera images. The inter-fractional setup errors were calculated by repeating the same setup five times. The intra-fractional displacements were evaluated while the subjects remained in the setups for 20 min. These setup errors and displacements were compared among the setups with different immobilization methods. The intra-fractional displacements were also compared between this study and previous studies in the supine posture.Results: Inter-fractional setup errors in the abdominal setups were reduced from 6.6 ± 3.3 to 3.9 ± 1.7 mm by using the masks. The HN setup using both the leg immobilization devices and backrest attachments had the setup errors of 2.9 ± 1.7 mm. This was smaller than the setup errors observed in three other HN setups that did not use either or both of the devices together. Intra-fractional displacements of these abdominal and HN setups with the immobilization devices were 1.9 ± 1.1 and 1.8 ± 1.5 mm, respectively, which were smaller than those in the other setups. These displacements were equivalent to those in the previous studies. Conclusions: Utilizing the masks increased upright setup accuracy in the abdominal setup. The leg immobilization devices and backrest attachments provided the highest setup accuracy in the upright HN setup. These findings will be useful to expand the applicability of upright radiotherapy for various cancer treatments.journal articl
Cancer in disguise: parasite within
No full textCancer does not simply develop unchecked-it strategically exploits its host with parasitic precision. From immune evasion to tissue remodeling, cancer cells mirror the survival strategies of parasitic helminths. This resemblance suggests that malignant cells have co-opted deeply conserved, evolutionarily honed tactics used by parasites to persist within their hosts. By mimicking helminths, cancer cells may also engage type-2 immune responses, traditionally associated with anti-parasitic defense, as part of the host's attempt to control their expansion. Such parallels could also help explain why type-2 immunity, once considered tumor-promoting, has recently emerged as a potential source of tumoricidal activity. In this Perspective, we explore mechanistic parallels between cancer and helminth infection. Recognizing the parasitic nature of cancer cells not only challenges established models of oncogenesis but also reveals mechanisms that could be leveraged for therapy.journal articl