National Institutes for Quantum and Radiological Science and Technology
National Institute of Radiological Science: NIRS-Repository / 放射線医学総合研究所 学術機関リポジトリNot a member yet
37195 research outputs found
Sort by
Development of a scanning NV probe microscope with multiple near-surface NV centers
No full textIn this study, we expect that a probe with a small number of NV centers adjacent within a hundred-nanometer distance can give us additional useful information for the target sample. To fabricate the near-surface multiple NV centers, a study reported that the diamonds were implanted with C32N8H18 molecules, having formed multiple adjacent NV centers3). In this study, we examined the C32N8H18 molecules implanted sample to observe one and two NV centers in a photoluminescence for the development of a scanning NV probe containing multiple proximate NV centers.EM-NANO 2025conference poste
Alterations of striatal phosphodiesterase 10?A and their association with recurrence rate in bipolar I disorder
No full textPhosphodiesterase 10 A (PDE10A), a pivotal element of the second messenger signaling downstream of the dopamine receptor stimulation, is conceived to be crucially involved in the mood instability of bipolar I disorder (BD-I) as a primary causal factor or in response to dysregulated dopaminergic tone. We aimed to determine whether striatal PDE10A availability is altered in patients with BD-I and assessed its relationship with the clinical characteristics of BD-I. This case-control study used positron emission tomography (PET) with 2-(2-(3-(4-(2-[18F]fluoroethoxy)phenyl)-7-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)ethyl)-4- isopropoxyisoindoline-1,3-dione ([18F]MNI-659), a radioligand that binds to PDE10A, to examine the alterations of the striatal PDE10A availability in the living brains of individuals with BD-I and their association with the clinical characteristics of BD-I. [18F]MNI- 659 PET data were acquired from 25 patients with BD-I and 27 age- and sex-matched healthy controls. Patients with BD-I had significantly lower PDE10A availability than controls in the executive (F = 8.86; P = 0.005) and sensorimotor (F = 6.13; P = 0.017) subregions of the striatum. Lower PDE10A availability in the executive subregion was significantly associated with a higher frequency of mood episodes in patients with BD-I (r = ?0.546; P = 0.007). This study provides the first evidence of altered PDE10A availability in patients with BD-I. Lower PDE10A availability in the executive subregion of the striatum is associated with an increased recurrence risk, suggesting that PDE10A may prevent BD-I relapse. Further studies are required to elucidate the role of
PDE10A in BD-I pathophysiology and explore its potential as a treatment target.journal articl
Entanglement in 2p atom pairs in H2 photodissociation as studied with measuring the angular correlation function of Lyman-α photon pairs on a whole sphere
No full textAn angular correlation function (ACF) of a pair of Lyman-α photons produced in photodissocia- tion of H2 with linearly polarized incident light is measured on a whole sphere at a 33.66-eV photon energy so that we may distinctly substantiate that the 2p atom pairs are in the state previously identified by Torizuka et al. as the 2p atom-pair state [Phys. Rev. A 99, 063426 (2019)], who measured the ACF only on a circle in the plane perpendicular to the incident light beam. The 2p atom-pair state determined with much less uncertainty than before is investigated in terms of whether or not the state is entangled. We discover that the pair of fragment H(2p) atoms is certainly entangled in terms of the electron-electron entanglement, and obtain the entanglement entropy of the 2p atom-pair state. The similar discussion is made in terms of the electronic spatial-spin en- tanglement too, where the spatial motion and spin motion of electrons are considered non-identical partial systems at variance with the former electron-electron entanglement. It turns out that the pair of fragment H(2p) atoms is entangled in terms of the electronic spatial-spin entanglement as well as the electron-electron entanglement.journal articl
Clinical and Pathological Features of FTDP-17 with MAPT p.K298_H299insQ Mutation
No full textBackground: MAPT is a causative gene in frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), a hereditary degenerative disease with various clinical manifestations, including progressive supranuclear palsy, corticobasal syndrome, Parkinson's disease, and frontotemporal dementia.
Objectives: To analyze genetically, biochemically, and pathologically multiple members of two families who exhibited various phenotypes of the disease.
Methods: Genetic analysis included linkage analysis, homozygosity haplotyping, and exome sequencing. We conducted tau protein microtubule polymerization assay, heparin-induced tau aggregation, and western blotting with brain lysate from an autopsy case. We also evaluated abnormal tau aggregation by using anti-tau antibody and PM-PBB3.
Results: We identified a variant, c.896_897insACA, p.K298_H299insQ, in the MAPT gene of affected patients. Similar to previous reports, most patients presented with atypical parkinsonism. Biochemical analysis revealed that the mutant tau protein had a reduced ability to polymerize microtubules and formed abnormal fibrous aggregates. Pathological study revealed frontotemporal lobe atrophy, midbrain atrophy, depigmentation of the substantia nigra, and four-repeat tau-positive inclusions in the hippocampus, brainstem, and spinal cord neurons. The inclusion bodies also stained positively with PM-PBB3.
Conclusions: This study confirmed that the insACA mutation caused FTDP-17. The affected patients showed symptoms resembling Parkinson's disease initially and symptoms of progressive supranuclear palsy later. Despite the initial clinical diagnosis of frontotemporal dementia in the autopsy case, the spread of lesions could explain the process of progressive supranuclear palsy. The study of more cases in the future will help clarify the common pathogenesis of MAPT mutations or specific pathogeneses of each mutation.journal articl
Significant Effect of Carbon-Ion Radiation Therapy Combined With Androgen Deprivation on Biochemical Recurrence Rates in High-Risk Prostate Cancer Patients: A Two-Center Controlled Trial Compare With X-Ray External Beam Radiation Therapy.
No full textTo compare the effects of carbon-ion radiation therapy (CIRT) and external beam radiotherapy (EBRT) on the prognosis of patients with prostate cancer.journal articl
Homogeneous spin-dephasing time of NV- centre in millimetre-scale 12C- enriched high-pressure high-temperature diamond crystals
No full textNegatively charged nitrogen vacancy (NV ) centres in diamond crystals are promising colour centres for high-sensitivity quantum sensors. A long dephasing time (T > 10 μs) is essential for achieving increased sensitivity and higher uniformity of T in millimetre- scale diamond is strongly desired for femto-tesla weak magnetic field detection. High uniformity of T for NV centres is achieved herein. The median value of T , , in the C-enriched high-pressure, high-temperature (HPHT) grown diamond with a nitrogen concentration of 1.3 ± 0.4 ppm is 4.5 μs. The variance of T is only 10% over a millimetre-scale region (1.1 × 1.1 mm ) within the 0.4 mm thick {111} growth sector. is ~2/3 times the value limited by the dipole-dipole interaction from the electron-spin bath of nitrogen impurities, suggesting that the residual strain gradient in the HPHT diamond crystal partially limits T . Reducing the strain gradient in diamond crystals provide a pathway to achievement of high sensitivity magnetometry using NV quantum sensing.journal articl
New Approach to Evaluate Joint Delamination Mechanism of Divertor by Finite Element Analysis Applying Cohesive Zone Model (CZM); Parametric Study on the Maximum Traction under Heating
No full textTo evaluate the delamination mechanism of the joint interfaces of a plasma-facing component, a new approach using the finite element analysis (FEA) applying the cohesive zone model (CZM) is proposed. The parametric study on the maximum traction τmax, which is one of the principal CZM parameters, was conducted for compensating the lack of material data. Monotonic heat loading was applied to the surface up to 20 MW/m2 in 1 second. The traction- separation law was assumed to be bilinear, which represents the relation between the representative crack stress and its opening displacement used for CZM. In the parametric study, three assumptions of τmax were defined, (1) equal to the weaker bulk strength (Copper), (2) considering temperature dependency, and the average value of the strength ratio of the interface to bulk copper, and (3) considering as well as (2) but the lowest value of the ratio. Results of the parametric study suggest shear stress-governed (mode II) delamination without vertical crack propagation in tungsten monoblock. Meanwhile, the joint interface shows compression, which means the interface remains in contact. Therefore, it is suggested that the degradation of cooling capability does not happen during the heating process unless vertical cracks in tungsten do not propagate into the interface.journal articl
Visualization of heavy ion particle Bragg peaks in water by ultrasound imaging
No full textMethods for visualizing charged particles in water have been extensively studied, whether for observing subatomic particles originating from space or monitoring charged particle beams used in radiation therapy. At the Heavy Ion Medical Accelerator in Chiba (HIMAC) facility of the National Institute of Radiological Sciences, we conducted ultrasound echo imaging of a water volume irradiated with 500 MeV n?1 Fe ions using an ultrasound imaging device. The resulting ultrasound echo images revealed microbubble-like signals near the Fe ion Bragg peak. Although the
intensity of the Fe ion beam pulses was insufficient to boil the water, and the ultrasound device did not generate sound pressure levels high enough to induce cavitation, microbubbles were nonetheless observed in the ultrasound echo images. These microbubbles likely formed through a mechanism in which microscopic cavities (bubble nuclei) created by individual Fe ions aggregated to form larger cavities, leading to the appearance of microbubbles.journal articl
Research on pebble characterizations and gas pressure in Li2TiO3 pebbles bed
No full textLi2TiO3 pebbles fabricated by an emulsion process are one of the most promising candidate materials as tritium breeders for fusion applications. In order to understand relation between the packing fraction and pebbles properties, it is essential to investigate the fundamental properties of the pebbles. In this study, it was found out that Li2TiO3 pebbles fabricated by the emulsion process contain single phases and have an average diameter of 0.99 mm with a significantly narrow size distribution. These pebbles exhibited the following fundamental
properties: average grain size of less than 5 μm, porosity of about 15 %, closed porosity of 0.75 %, sphericity of 0.985, specific surface area of 0.4078 m2/g, average surface roughness of about 0.434 μm. In parallel with the characterization, the gas pressure variation in the Li2TiO3 pebble bed was investigated. The measured value was found to be in good agreement with the calculated value based on the Kozeny-Carman equation.journal articl
Identification of a Functional Flavanone 3-Hydroxylase Gene in a Fragrant Wild Cyclamen Species (Cyclamen purpurascens)
No full textAlthough the fragrant wild cyclamen, Cyclamen purpurascens, is widely used as a parent plant for breeding of fragrant cyclamen cultivars, the color variety of fragrant cyclamen is limited. To develop cultivars with a wider range of flower colors, it is crucial to understand the flavonoid biosynthetic pathway involved in flower color in C. purpurascens as a crossbreeding parent. In this study, we isolated the gene (CpurF3H) encoding flavanone 3-hydroxylase, a key enzyme in determining flower color in cyclamen, from C. purpurascens for the first time and investigated its expression and function. The full-length cDNA sequence of CpurF3H obtained from young petals contained a 1,113-bp open reading frame (ORF) encoding 371 amino acids, showing 82.1? 88.0% amino acid sequence identity with F3Hs from other plant species. The expression analysis showed that CpurF3H is strongly expressed in young petals, but rapidly decreases in petals following anthesis, suggesting that it functions during the early stages of flower development. Next, in vitro assays showed that recombinant CpurF3H proteins can convert naringenin to dihydrokaempferol. In addition, a complementation assay using the Arabidopsis thaliana f3h mutant confirmed the accumulation of anthocyanins in CpurF3H-transformed plant. Overall, these results strongly suggest that CpurF3H participates in flavonoid biosynthesis and flower coloration in C. purpurascens.journal articl