大型核融合試験施設におけるメガワットミリ波ジャイロトロン発振器周辺の電磁環境調査

将来のエネルギー源として開発が進められている磁場閉じ込め方式の核融合研究では，高温プラズマの生成や制御，プラズマ加熱及び計測のために大電力高周波発振機器が利用されている．本論文では，核融合科学研究所の大型ヘリカル装置で使用されているメガワットミリ波ジャイロトロン発振器(周波数: 77 GHz，最大出力: 1～1.5 MW/2秒)を対象とし，作業従事者の安全管理を目的に，ホーンアンテナを用いて機器周辺での電磁環境を定点調査した．その結果，77 GHz発振器からおよそ30 m離れた場所で観測された漏洩電界の周波数は，77 GHzが最も強く，そこから数GHz離れた両側の周波数領域にも微弱なスプリアススペクトルが確認された．また，同じ場所で，数十秒から数百秒の発振運転に伴う漏洩電界(最大実効値: 数V/m)が観測された．電界の漏洩箇所は，ジャイロトロン発振器を構成する接地電位の電子ビームコレクターと，その他の部位とを電気的に絶縁するために具備された窒化ケイ素製絶縁部と推定された．本研究により，大型核融合試験施設におけるメガワットジャイロトロン発振器周辺のミリ波帯での漏洩電界の実態を初めて明らかにした

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways

Water Vapor Adsorption Properties of Honeycomb-Type Zeolites for Tritium Removal Systems

We have proposed the application of a honeycomb-type adsorbent and catalyst for an advanced tritium removal system. Honeycomb-type materials exhibit a much lower pressure drop than pellet-type materials. In this study, the water vapor adsorption properties of various types of honeycomb adsorbents were evaluated using the breakthrough method at a constant flow rate of 307 cm3/min under various temperature and water vapor partial pressure conditions. The results revealed that the adsorption capacity of water vapor on the honeycomb-type zeolite increased with the water vapor partial pressure and the zeolite content of the honeycomb adsorbents. Furthermore, the honeycomb-type zeolite was found to have a higher adsorption rate than the pellet-type zeolite, and the temperature required for regeneration of the honeycomb-type zeolite was at least 450 K. From the viewpoint of practical use, the honeycomb-type adsorbent that contained 50% zeolite with 200 cells per square inch was considered to have superior adsorption properties and a lower pressure drop among a series of honeycomb-type adsorbents