In many countries, lemons are waxed for post-harvest protection. However, in Japan, lemons are typically sold unwaxed because they are a special domestic product whose peels are often consumed directly or used in cooking. This practice poses issues for Japanese-island-grown lemons, which may require a minimum of one week for transport. Unwaxed lemons are generally susceptible to mold contamination and have a short shelf life of only two weeks, making their transportation from the island to the mainland impractical. To address these issues, we developed an irradiation-based method that uses soft (low-energy) electron beams (EBs) to exclusively sterilize mold on lemon peels. Thereafter, we investigated the effect of the treatment on the shelf life of the lemons by uniformly irradiating them with EBs. The results revealed that while the proposed electron irradiation sterilized the mold, it triggered the browning of the lemon peel, rendering the method unsuitable for long-term storage.

To improve the measurement accuracy of the Compton camera system mounted on the unmanned helicopter, the scintillator coordinates fixed in the previous analysis were replaced with those corrected for ever-changing positions and tilts for each event. As a result of evaluating the accuracy of the reconstructed gamma-ray images, improved correlations with the ground-measured values certainly indicated the effectiveness of this method.

線量評価は，核医学治療の安全性や有効性を評価するために必要不可欠である。線量評価には，複数回の画像収集による標的組織内のTime-integrated Activity（TIA）が必要となる。TIAは画像の定量性およびフィッティング法で精度が変化する可能性がある。本稿では，線量評価に必要なイメージング及びTIAについて基本から最新の動向まで解説する。

Silver iodide (AgI) is an ice-nucleating substance because its crystal is structurally analogous to ice crystal. To extend the application of AgI as a supercooling breaker, we immobilized AgI precipitates onto an anion-exchange fiber prepared by radiation-induced graft polymerization. The AgI-immobilized fiber was immersed in water in a plastic tube before the temperature of the tube-placed water bath was decreased from 1 to −4°C. In the presence of the AgI-immobilized fiber, the breaking of supercooling of water was demonstrated by direct observation of the phase transition of water and by measuring the temperature of water.

近年，深層学習を用いた画像解析が注目されている。放射線生物学分野への応用可能性の検討を目的として，本研究では深層学習に基づく細胞セグメンテーションアルゴリズムCellpose 2.0を用いて，細胞周期を同調させたヒト子宮頸がん由来HeLa細胞において放射線被ばく後の細胞接着面積の変化を詳細に解析した。その結果，G1期細胞ではX線被ばく後に細胞接着面積が増加するのに対し，G2期細胞では減少することを新たに見出した。今後，このような人工知能利用による放射線生物学研究のさらなる進展が期待される。

Neutron capture therapy (NCT) uses secondary particle to treat tumor. Boron has been applied to NCT in clinics, and gadolinium has also attracted the attention. Our group attempted a new candidate element, rhodium, because of its advantages, such as 100% natural abundance, long range (beta ray), neutron cross-section peak, and fitness to accelerator-based neutrons. To reduce toxicity and increase tumor accumulation, rhodium encapsulated liposomes (Rh-Lip) were synthesized. After 24 h exposure to rhodium solution, the cell viability increased to 90% when the rhodium concentration was diluted to 0.063 mg/mL; in contrast, it was up to 90% when rhodium concentration was diluted to 0.25 mg/mL in the Rh-Lip group. Moreover, in the Rh-Lip group, 387.3 ppm rhodium remained in the tumor 3 h after administration, but only 42.6 ppm remained in the rhodium solution group. After neutron irradiation, Rh-Lip showed a slower tumor growth rate and damage to tumor cells from pathological analysis, suggesting that rhodium is a potential element for NCT.

Sodium (Na) exclusion is vital for plants to cope with salt stress, and the plasma membrane Na + /H + antiporter, SALT OVERLY SENSITIVE 1 (SOS1), has been known to play a central role in this process although the function of this molecule is not completely understood. In this study, we performed 22 Na + radiotracer experiments to investigate the function of SOS1 in the mature root zone. Arabidopsis thaliana seedlings were placed on the gel medium, which had air gaps to separate the medium at the mature root zone from that at the root apex zone. Then, 22 Na + was added to the root apex zone for 4 h, and the radioactivity in the mature root zone with 5 mm in length and in the mature root zone gel was measured. As a result, we found that knock-out of SOS1 caused 22 Na + accumulation in the mature root zone and reduction of 22 Na + exclusion to the gel, demonstrating that Na + delivered via the xylem is excluded to the rhizosphere by SOS1 in the mature root zone.

再生医療の活性化に伴い，幹細胞などの再生医療製品の国際搬送の必要性が高まっている。現状の国際搬送は航空機搬送が主体であるが，空港におけるセキュリティ検査のX線や宇宙放射線による被ばくの影響が懸念される。日本発着国際便による1回の輸送で宇宙放射線が細胞核にヒットする確率は高くはないが，細胞死や癌化といった問題だけでなく，幹細胞に求められる分化能に対する影響を否定することができない。そこで，航空機輸送に伴う低線量被ばくが与える影響の解明と併せて，宇宙放射線を効果的に遮蔽できる搬送容器や搬送システムの開発が必要である。

交換性カリウム濃度がイネの放射性セシウム吸収に影響を与えない程度に高い条件では、玄米の放射性セシウム濃度は，土壌中の溶存態放射性セシウム量から精度よく予測できる。しかし，溶存態放射性セシウム量の実測には，大量の土壌溶液採取やろ過・濃縮等の多大な労力が必要である。そこで，亜鉛置換型プルシアンブルーを担持した吸着シートで土壌中の溶存態放射性セシウムを吸着し，シートに吸着した溶存態放射性セシウム量から玄米放射性セシウム濃度を簡易に予測することが可能か否かを検討した。表面をメンブランフィルターで被覆することにより土壌粒子の付着を防ぐ加工をしたセシウム吸着ディスクを現地水田の作土に2週間埋設し，溶存態放射性セシウムを回収した。吸着シートに回収された放射性セシウム量は，玄米放射性セシウム濃度と高い正の相関があった。分げつ期に吸着シートを埋設し，回収された放射性セシウム濃度を分析することで，大量の土壌溶液の採取や土壌理化学性の分析を必要とせず，玄米中放射性セシウム濃度を予測出来る可能性が示された。