National Institutes for Quantum and Radiological Science and Technology
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37195 research outputs found
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A 3D-printed device for separating short-lived radioisotopes from target ion
No full textIn this study, a new disposable 3D-printed device was developed to rapidly handle practical solution volumes (~10 mL) containing dissolved metal RIs and targets. The overall separation process is carried out in three steps: selective chelation, target ion adsorption, and finally, UV-induced decomposition of the metal complex. All of these steps are achieved in-line within the developed device. The system performance was evaluated for two different metal RI/target combinations: Ga/Zn and Zr/Y. The results showed that the developed system is universally applicable for many types of nuclides.journal articl
Molecular dynamics study on clustered DNA damage: AP sites on the same strand
No full textAlthough radiation-induced clustered DNA damage can have critical biological consequences, the underlying molecular mechanisms remain unclear. To explore the effect of clustered DNA damage on DNA structure and dynamics, we performed molecular dynamics simulations on damaged DNA with two AP sites on the same strand, that is, a tandem AP cluster. The results showed that the cluster insertion of the two AP sites had a significant impact on the DNA’s local and global structures. Local structural deformations as well as the extrahelical form, AP-base pairs, and irregular base pairs were frequently observed. Unlike a single AP site, the tandem AP cluster revealed that these local structural features occurred simultaneously within a small separation. Moreover, we found that the presence of tandem AP sites induced global bending of DNA. This suggests that the present case with tandem AP sites may have a non-negligible impact on the biological function of damage repair.journal articl
Unveiling the impact of CD133 on cell cycle regulation in radio- and chemo-resistance of cancer stem cells
No full textThe adaptation of malignancy to therapy presents a significant challenge in cancer treatment. The cell cycle plays a crucial role in regulating the evolution of radio- and chemo-resistance in tumor cells. Cancer stem cells (CSCs) are the primary source of therapy resistance, with CD133 being one of the most recognized and valuable cell surface markers of CSCs. Evidence increasingly suggests that CD133 is associated with cancer resistance. The current understanding of the molecular biological function of CD133 is limited, leading to ongoing debates about its role in cancer biology. In this review, we explore recent research and emerging trends related to CD133 through extensive literature and content analysis. It was summarized that new insights into the relationships of CD133 and cell cycle signaling pathways in resistant CSCs. The aim of this review is to provide a foundational understanding of how these signaling pathways and their interactions impact cancer prognosis and inform treatment strategies.journal articl
Mechanochemical Synthesis of H? Materials: Hydrogen-Rich Perovskite Oxyhydride with Lattice Strain as Ammonia Synthesis Catalyst
No full textWe succeeded mechanochemical synthesis of hydrogen-rich oxyhydride BaTiO3?xHx wherein the hydrogen solubility limit is expanded up to ~1, and observed the Ru/BaTiO2H catalyst showed notable catalytic activity. Those findings should be correlated with lattice strain inside the crystal, that was uncovered by Bragg coherent X-ray diffraction imaging (Bragg-CDI) technique.journal articl
Nonthermal Effect of Microwave Irradiation on the Molecular Level: Emergence of Coherent Subterahertz Vibrations of Hydration Water in Reverse Micelles
No full textIt is believed that the effect of microwave irradiation on samples has a thermal
origin. Nevertheless, the nonthermal effect is often proposed and remains controversial because of incomplete experimental results such as the lack of local temperature around reactant molecules. We have conducted a new method of in situ terahertz (THz) time domain spectroscopy under microwave (MW) irradiation at 2.45 GHz for water in nanoscale reverse micelles, allowing one to determine the temperature of this water and its lowfrequency vibrations simultaneously. Comparison with the results of temperature-dependent
THz spectroscopy without MW irradiation has demonstrated that the water temperature in the reverse micelle is almost the same as the sample’s value measured by a thermographic camera under MW irradiation. In contrast, distinct sub-THz vibrational peaks of hydration water emerge nonthermally. Our findings provide a new aspect for understanding MW effects on the molecular level and may have biological implications.journal articl
A Phase I/II Study of Ultra-Hypofractionated Carbon-ion Radiation therapy for Low- and Intermediate-Risk Localized Prostate Cancer.
No full textWe report herein the 3-year results of a phase I/II prospective study of 4-fraction course of carbon-ion radiation therapy (CIRT) in patients with localized prostate cancer.journal articl
Multiple-Cell Upset Analysis on 16/12-nm Bulk FinFET SRAM Caused by Proton Irradiation
No full textThe effects of proton-induced multiple-cell upsets (MCUs) on 16 and 12-nm Fin Field Effect Transistor (FinFET) static random-access memories (SRAMs) were studied. Their dependence on incident angle and supply voltage is discussed in terms of the MCU size and the fail-bit map (FBM). For perpendicular proton irradiation, we compared the MCU characteristics of FinFET SRAMs with 20-nm bulk planar SRAMs. In the proton energy dependence of single event upset (SEU) cross section, peak structures caused by proton direct ionization (PDI) were observed. At the nominal voltage condition, the peak was observed in the 20-nm bulk planar SRAM, but not in the 16 and 12-nm FinFET SRAMs. At the low voltage condition, however, the peak was observed even in the FinFET SRAMs. For the 16 and 12-nm FinFET SRAMs, the maximum size of MCUs was 3-bits, whereas that was 7-bits for 20-nm bulk planar SRAMs. Furthermore, the differences of the physical pattern of MCUs is observed between 16-nm FinFET and 20-nm SRAMs in perpendicular proton irradiation, where the 16-nm FinFET SRAM tends to have a rectangular shape with longer side in the bit-line (BL) direction. This clearly suggests that multiple-bit upsets (MBUs), which is known as uncorrectable MCUs, hardly occur in the 16 and 12-nm FinFET SRAM. For the angular irradiation, MBU probability in all MCU events reached 73% when tilting the SRAM at 75o across the fin body direction. However, the observed MBU size was up to 2-bits, indicating bit-interleaves with more than 2-bits can be effective for mitigating MBUs in 16 and 12-nm FinFET SRAMs.journal articl
Human biodistribution and radiation dosimetry of two novel α-synuclein PET tracers, F-SPAL-T-06 and F-C05-05.
No full textF-SPAL-T-06 and F-C05-05 are two novel positron emission tomography (PET) radioligands targeting α-synuclein fibrils. Our study aimed to evaluate the biodistribution, safety, and radiation dosimetry of each tracer in humans. Biodistribution and radiation dosimetry studies were carried out with two healthy volunteers for each tracer, F-SPAL-T-06 (one female and one male volunteer, both aged 63 years) and F-C05-05 (one female and one male volunteer, aged 63 and 73 years, respectively). After injection of either tracer, dynamic PET images were acquired from head to upper thigh. Effective dose of each tracer was estimated using OLINDA/EXM Version 2.2. Injection of either of the tracers caused no adverse effects. Greatest uptake of both tracers was observed in the liver and small intestine. The estimated absorbed doses were highest in the biliary tract, followed by the lower large intestinal wall. Effective doses were 35.9 μSv/MBq for F-SPAL-T-06 and 30.5 μSv/MBq for F-C05-05. F-SPAL-T-06 and F-C05-05 are safe for in vivo PET imaging of humans. Their mean effective doses were 6.6 mSv for F-SPAL-T-06 and 5.6 mSv for F-C05-05 when 185 MBq of either tracer was given to a subject, and they were comparable to other amyloid and tau PET tracers labelled with F.Trial registration Trial registration number: jRCTs031210180, Registered date: 2nd July 2021 (F-SPAL-T-06) https://jrct.niph.go.jp/en-latest-detail/jRCTs031210180 and Trial registration number: jRCTs031220123, Registered date: 9th June 2022 (F-C05-05) https://jrct.niph.go.jp/en-latest-detail/jRCTs031220123 .journal articl
X-ray photolysis of a hypervalent iodine compound, 4-carboxy-2-iodosobenzoic acid, via iodine K-shell excitations and ionizations
No full textWe examined decomposition reactions of a hypervalent iodine compound, 4-carboxy-2-iodosobenzoic acid (IBA-COOH), induced by monochromatic X-ray irradiations around the iodine K-edge energy region in a phosphate buffer. A decomposition product, 2-iodoterephthalic acid (ITPA), was identified by liquid chromatography-mass spectrometry for all experiments, indicating the I-O bond breakages were induced by the X-ray irradiations. The ITPA production to IBA-COOH decomposition ratio for the second iodine K-shell resonant excitation (33.22 keV irradiation) was higher than that for the first excitation (33.18 keV irradiation). Those findings suggest that the iodine K-shell resonant excitations can induce selective bond breakages of IBA-COOH, and therefore the IBA-COOH could be a promising protecting group of caged compounds activated by the X-ray irradiations.journal articl
Cooperative inhibition in cytochrome P450 between a substrate and an apparent non-competitive inhibitor
No full textCytochrome P450 (CYP) enzymes bind a heme group that acts as a catalytic center. Inhibition mechanisms in CYP enzymes have been studied extensively by biochemical and structural analyses. Non-competitive inhibitors are generally believed to bind to allosteric sites remote from the active site to form enzyme-substrate-inhibitor (ESI) complexes. Docking simulations predict the binding sites of non-competitive inhibitors to CYP enzymes, but to date there has been no experimental structural verification of ESI complexes formed by CYP enzymes. We performed biochemical and structural analyses of CYP105A1 using the imidazole-containing inhibitors ketoconazole, lanoconazole, and miconazole. Spectroscopic analyses showed that ketoconazole and miconazole act as competitive inhibitors, whereas lanoconazole acts as a non-competitive inhibitor of CYP105A1. The obtained X-ray structures of enzyme-inhibitor (EI) complexes showed that lanoconazole can bind in various orientations to the heme iron compared with ketoconazole and miconazole. We also determined the X-ray structure of an ESI complex comprising CYP105A1, diclofenac, and lanoconazole. This structure shows that lanoconazole binds to the heme iron and that diclofenac closely interacts with the bound lanoconazole but it is positioned distant from the heme group. Quantum mechanical calculations indicate that Cl-π and electrostatic interactions between diclofenac and lanoconazole, and electrostatic interactions between diclofenac and positively charged arginine residues, stabilize formation of the ESI complex. Based on these results, we propose a mechanism for cooperative inhibition between a substrate and an apparent non-competitive inhibitor.journal articl