In this study, we aimed to find out new indications of radon therapy and examined whether radon inhalation induced antidepressant-like effects in mice. First, we investigated the effects of radon inhalation on the forced swim stress-induced model of depression. We evaluated depression-like symptoms before and after forced swim test (FST). All mice were examined the locomotor activity and the responses to novel environments by open field test, and only depression groups performed depression-like behavior by FST. Pre-treated mice inhaled radon at background (BG) level, or at a concentration of 2,000 Bq/m³ for 24 h before FST, and post-treated mice inhaled similar levels of radon after the FST. Forced swim stress induced depression-like behavior, and 2,000 Bq/m³-radon inhalation alleviated depression-like symptoms compared to BG level concentration. Concurrently, Swim stress induced the decrease in norepinephrine and dopamine levels in brain tissue. Furthermore, swim stress-induced depression reduced superoxide dismutase activity in blood plasma and increased lipid peroxide content in brain tissue. Treatment with radon inhalation produced antidepressant-like effects, i.e., enhanced monoamines, including Serotonin, norepinephrine and dopamine levels in brain tissue, as well as depression-like behavior. These findings indicated that radon inhalation prevented and alleviated swim stress-induced depression-like symptoms in mice.

To elucidate the pathways for radioactive caesium contamination in persimmon fruit, we investigated the effects of radioactive caesium concentration on translocation via the calyx. The calyces were inoculated with water containing caesium-137 (10, 100, 1000 Bq/kg) and the caesium-137 concentration was measured using a germanium semiconductor detector. The translocation of caesium-137 via the calyx to the flesh was confirmed. The caesium-137 concentration in the flesh increased with proportionally increases in the caesium-137 concentration in the water. On the other hand, the transfer rate did not change with increases in the caesium-137 concentration in the water: it was 4.01％ at 1000 Bq/kg and 4.24％ at 100 Bq/kg. To evaluate the risk of contamination via the calyx, we measured amount of caesium-137 in the water falling from the surrounding environment (rain, forests, trees, etc.) onto a persimmon tree and the water which flowed along the branches. At orchard conducted the washing or scraping of bark, this environmental water was shown to be unlikely to influence the caesium-137 concentration in the fruit.

The recent development of selective in vivo tau PET imaging ligands including [¹¹C]PBB3, [¹⁸F]THK5351 and [¹⁸F]T807 (AV1451) has allowed exploration of the presence and extent of tau pathology in patients suspected of having tauopathies. In Alzheimer’s disease, [¹¹C]PBB3-PET data were closely consistent with the spreading of tau pathology with disease progression described as Braak staging. In non-Alzheimer’s disease tauopathies, such as progressive supranuclear palsy and corticobasal syndrome, tau PET imaging has made it possible to detect the deposition of aggregated tau in specific lesions. Selective tau imaging might be useful as a diagnostic and prognostic biomarker, and a surrogate marker for the evaluating of therapeutic efficacy and patient recruitment for trials of anti-tau disease modifying therapy.

Chopper-type neutron spectrometers at pulsed neutron sources can measure dynamics over a wide momentum-energy space, and are widely used in studies of liquids, soft mater, as well as solids. 4SEASONS is the first chopper spectrometer open for users among the four chopper spectrometers at J-PARC. It is designed for measurements of dynamics in the 10⁻¹–10² meV energy range with high flux and high efficiency. Examples of measurements on dynamics in single crystals performed at 4SEASONS are presented.

The High Resolution Chopper Spectrometer (HRC) is an inelastic neutron scattering instrument to study dynamics of materials in a wide energy space with high resolutions. Improvement of the HRC for realizing neutron Brillouin scattering experiments has enabled dynamical studies of polycrystalline and liquid samples. In high resolution experiments in a conventional energy momentum space, dynamics in numbers of strongly correlated electron systems have been revealed. In sub-eV neutron spectroscopy, studies of high energy magnetic excitations are in progress, and possibilities of observing electric excitations are discussed.