Scandium 45 in meteoritic irons

This report presents the results of determinations of cosmogenic ^Sc and light noble gases in iron meteorites. Sc and REE were simultaneously determined using radiochemical neutron activation method. This method is sensitive enough for detection of as little as lower than 10^gSc/g, compared to the level of cosmic ray effects in irons which are usually in the range of 10^-10^gSc/g. The lowest concentration found in irons was 2×10^gSc/g in the Campo del Cielo and similar contents were observed in the Gibeon, DRP-78008 (and Brenham-metal). Even at these low levels, Sc seems mostly attributable to cosmic ray production. The Sc content in irons is best compared with cosmogenic ^4He. The ratio of Sc to ^4He, approximately 1×10^gSc/1×10^cc ^4He, or an average atomic ratio of 1 : 19±3,was observed independent of shielding. Technical aspects of metal phase separation from ordinary chondrites were studied. In one Peace River metal sample, 0.9 ppbSc was found. This number corresponds to 0.01% of the stone phase in the metal. This level of contamination seems still higher than the cosmogenic level of 0.2 ppbSc expected in the metal phase of this meteorite

精神疾患におけるマイクログリア由来ニューレグリン発現

Several studies have revealed that neuregulins (NRGs) are involved in brain function and psychiatric disorders. While NRGs have been regarded as neuron- or astrocyte-derived molecules, our research has revealed that microglia also express NRGs, levels of which are markedly increased in activated microglia. Previous studies have indicated that microglia are activated in the brains of individuals with autism spectrum disorder (ASD). Therefore, we investigated microglial NRG mRNA expression in multiple lines of mice considered models of ASD. Intriguingly, microglial NRG expression significantly increased in BTBR and socially-isolated mice, while maternal immune activation (MIA) mice exhibited identical NRG expression to controls. Furthermore, we observed a positive correlation between NRG expression in microglia and peripheral blood mononuclear cells (PBMCs) in mice, suggesting that NRG expression in human PBMCs may mirror microglia-derived NRG expression in the human brain. To translate these findings for application in clinical psychiatry, we measured levels of NRG1 splice-variant expression in clinically available PBMCs of patients with ASD. Levels of NRG1 type III expression in PBMCs were positively correlated with impairments in social interaction in children with ASD (as assessed using the Autistic Diagnostic Interview-Revised test: ADI-R). These findings suggest that immune cell-derived NRGs may be implicated in the pathobiology of psychiatric disorders such as ASD.博士（医学）・乙第1404号・平成29年6月28日Copyright © 2017 Elsevier Inc. All rights reserved