スペクトル取得型光学オゾンゾンデ用分光器の感度波長特性

第6回極域科学シンポジウム分野横断型セッション：[IM] 横断　中層大気・熱圏11月17日（火）　国立極地研究所１階交流アトリウ

Study on measuring device arrangement of array-type CdTe detector for BNCT-SPECT

AimTo design the measuring device arrangement of array-type CdTe detector for BNCT-SPECT.BackgroundIn a boron neutron capture therapy, a very serious unsolved problem exists, namely that the treatment effect for BNCT cannot be known during irradiation in real time. Therefore, we have been developing a so-called BNCT-SPECT with a CdTe detector, which can obtain a three-dimensional image for the BNCT treatment effect by measuring 478[[ce:hsp sp="0.25"/]]keV gamma-rays emitted from the excited state of 7Li nucleus created by the 10B(n,α) reaction. However, no practical uses were realized at present, because BNCT-SPECT requires very severe conditions for spatial resolution, measuring time, statistical accuracy and energy resolution.Materials and methodsThe design study was performed with numerical simulations carried out by a 3-dimenaional transport code, MCNP5 considering the detector assembly, irradiation room and even arrangement of arrayed CdTe crystals.ResultsThe estimated count rate of 478[[ce:hsp sp="0.25"/]]keV gamma-rays was sufficiently large being more than the target value of over 1000[[ce:hsp sp="0.25"/]]counts/h. However, the S/N ratio did not meet the target of S/N[[ce:hsp sp="0.25"/]]>[[ce:hsp sp="0.25"/]]1. We confirmed that deterioration of the S/N ratio was caused by the influence of Compton scattering especially due to capture gamma-rays of hydrogen. Theoretical calculations were thereafter carried out to find out whether anti-Compton measurement in an array-type CdTe detector could decrease the noise due to Compton scatterings.ConclusionsThe calculation result showed that the anti-coincidence would possibly increase the S/N ratio. In the next phase, an arrayed detector with two CdTe crystals will be produced to test removal possibility of the anti-coincident event

Production of C

Ethanol conversion to C3+ olefins, especially propylene, using Zr-modified H-ZSM-5 catalysts was investigated. Zr-modification to H-ZSM-5 zeolite could improve the initial yield of C3+ olefins and propylene and could reduce the initial yield of ethylene. In general, catalysts exhibiting the higher initial yield of propylene showed the steeper decrease in propylene yield as the reaction proceeded. However, Zr-modification to H-ZSM-5 could depress the decrease in propylene yield for aqueous ethanol. As cause of catalytic deactivation, carbon deposition on catalyst and framework collapse of zeolite support can be considered. The addition of water to Zr-modified H-ZSM-5 catalyst could depress carbon deposition in some degree, and, as a result, the decrease in propylene yield could be depressed

<ORIGINAL REPORT>X-ray scanning analytical microscopic and scanning electron microscopic studies of an unusual case of dens invaginatus

A mass was extirpated from the region of the maxillary right third molar of a 20 year-old patient. It was proved to be an extreme and unerupted case of dens invaginatus. The clinical and histopathological features have been presented in a previous paper. Ameloblasts and odontoblasts were noted along the surface of enamel or dentin. In the present study, X-ray scanning analytical microscopy (XSAM), a newly developed technique, together with scanning electron microscopy (SEM) was applied for the study of this malformed tooth. SEM study showed a strange arrangement of well-formed enamel and dentin in normal structures. The distribution of calcium (Ca) and phosphorus (P) was clearly observed by the XSAM method. It revealed that the bulk of dentin was composed of two kinds of dentin quite different in mineral content while their SEM appearances were similar. The part of the dentin near the dentinoenamel junction had much higher Ca and P concentrations than the outer parts. In conclusion, the disagreement between the microscopic findings and the XSAM findings suggests the importance of applying various methods in studies to obtain a comprehensive understanding of such malformation. In addition, the present investigation also points out the complexity of the disturbance ranging within the term dens invaginatus

Cost-effectiveness Analysis of Apixaban against Warfarin for Stroke Prevention in Patients with Nonvalvular Atrial Fibrillation in Japan

Abstract Purpose The aim of this study was to evaluate the cost-effectiveness of apixaban compared with to warfarin, current standard of care, for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF) in Japan. Methods A previously published lifetime Markov model was adapted to evaluate the cost-effectiveness of apixaban compared with warfarin in patients with NVAF in Japan. In the same model, the costs associated with each clinical event and background mortality were replaced with Japanese data. Whenever available, some of the utility parameters were derived from Japanese published literature. Lifetime horizon was selected to evaluate the value of the treatment benefit (stroke prevention) against potential risks (such as major bleedings) among patients with NVAF. Direct medical cost, long-term care cost, and quality-adjusted life years (QALYs) were calculated from the payers' perspective. Findings Compared with warfarin, treatment with apixaban was estimated to increase life expectancy by 0.231 year or 0.240 QALYs while treatment cost increased by ¥511,692 (US $5117 at an exchange rate of US$1 = ¥100). The incremental cost-effectiveness ratio was ¥2,135,743 per QALY (US $21,357 per QALY). On the basis of the results of the probabilistic sensitivity analysis, when the willingness-to-pay threshold was set at approximately ≥¥2,250,000 (US$22,500) per QALY, the probability of apixaban being cost-effective was ≥50%. Assuming a willingness-to-pay threshold of ¥5,000,000 (US $50,000) and ¥6,700,000 (US$67,000) in Japan, the probability of apixaban being cost-effective was 85% and 91%, respectively. Conclusion Although most participants in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial used for the efficacy data of apixaban in the model were non-Japanese patients, the impact of the limitations on our results was considered small, and our results were deemed robust because of the additional effect in Japanese patients compared with that in the global population according to the subanalysis of Japanese patients in the trial. Therefore, based on an adaptation of a published Markov model, apixaban is a cost-effective alternative to warfarin in Japan for stroke prevention among patients with NVAF