空间辐射环境模拟装置与空间辐射生物效应研究进展

空间环境中宇航员受到的高能辐射主要来源于太阳粒子事件、银河宇宙射线和地球捕获带中的高能离子及其次生放射性粒子。太空辐射暴露具有低剂量率、多品质辐射和高线性能量传递(LET)等特点,是宇航员在深空执行长时间太空探索任务时面临的主要风险因素。基于地面高能加速器的空间辐射模拟装置及空间辐射生物效应研究是空间辐射风险评估科学依据的关键。单离子微束技术作为一种先进的能提供精确至单离子精准辐照的辐照装置,是真实模拟空间高能辐射条件开展生物效应研究的独特平台。本文首先介绍了近地任务以及深空探索中的辐射环境以及世界各国可供开展空间辐射地基模拟的粒子加速器设施,以及近年来的空间辐射效应研究进展,最后介绍了兰州重离子研究装置的高能微束装置及其在空间辐射生物学研究中的应用。

Low Energy Heavy Ion Irradiation of Diamond Generates Nitrogen-vacancy Color Centers

Nitrogen-vacancy(NV)defect center with negative charge in diamond is an important solid-state doping system with wide applications in quantum computing,quantum sensing,and other fields.CVD diamond(nitrogen concentration of 10 ppm)and HPHT diamond(nitrogen concentration of 150 ppm)were irradiated by Ar^(11+)ions with 2.97 MeV,followed by vacuum annealing at 850℃for 1 h.

Design of 50 MeV Proton Microbeam Based on Cyclotron Accelerator

A 50 MeV proton microbeam facility that can provide accurate irradiation dose delivery is a powerful tool in space science,biology and cancer therapy studies.However,the poor beam quality of the cyclotron and the intense scattering at the slit position are the main challenges of the 50 MeV proton microbeam system.We present the optical design for a cyclotron-based 50 MeV proton microbeam system with a micro-sized resolution.Figure 1 shows the scheme of the 50 MeV proton microbeam system.Due to the large emittance and momentum spread of the beam provided by the cyclotron.

Chromatin Decompaction Induced by Histone Acetylation Inuences the Sensitivity of DNA to Ionizing Radiation

The DNA molecules of eukaryotes are densely packed and exist within the nucleus as chromatin.Chromatin organization is highly dynamic and plays a crucial role in the repair of DNA damage caused by ionizing radiation,associating with acetylation of lysine residues in histones H3 and H4.

Study on the Single Event Reliability of PAVLOV Neuron System

The reliability of the AI systems to the harsh space radiation is of great concerns with the increasing application in aerospace.Because of its neuromorphic device architecture and operation mode,low-power neuron chips have enormous potentials in resistance of single event effect,which is one of the most important failures of spacecraft caused by space radiation.In this work,a mixed-signal spiking neuron chip,named PAVLOV^([1]),has been studied at circuit and chip level with respect to its response to single event errors.

电离辐射诱导组蛋白乙酰化引起的染色质结构解聚研究

真核生物的DNA分子经高度压缩以染色质形式存在于细胞核中,染色质动态结构在DNA复制、基因转录和DNA修复等过程中起着重要的调控作用。核内染色质结构的原位高分辨解析和其结构变化定量表征一直受困于显微成像观测分辨率的限制。通过点击化学荧光标记EdU和STORM单分子定位显微成像,实验得到了细胞核内超分辨率染色质结构图像。基于提出的单分子团簇分析和最近邻距离算法分析发现,X射线辐照和TSA处理后的细胞核内核小体团簇数量显著增多,核小体团簇所占细胞核内的面积比相对于对照组增加,且团簇内平均EdU分子数降低。同时,重离子辐照活细胞在线成像实验获得的XRCC1招募动力学速率常数表明乙酰化处理使得DNA损伤密度降低。这些结果表明电离辐射和乙酰化处理均导致了染色质结构的松散化。STORM超分辨成像方法和分析算法及其获得的核小体团簇分布规律为染色质结构的松散提供了直接的定量表征数据支持。