应用量子点探针观察粒子辐射细胞损伤动态过程

荧光量子点由于具有发射荧光效率高、光稳定性好、无光漂白等优良特性,因此在生物学研究中得到广泛应用。用量子点标记细胞,通过量子点荧光可以对细胞进行长时程观察,实现活细胞动态示踪。利用量子点和DiO荧光染料对A549细胞膜双染,直观展示了量子点优于有机荧光染料的抗光漂白特性,并阐述了一种利用量子点对细胞A549进行标记并观测在α粒子辐照下细胞损伤动态变化过程的方法,这种方法对于阐明粒子辐射作用细胞的过程、了解辐射损伤的机理有一定的优势。     

单粒子束精确定位照射装置在CR-39膜上刻蚀中国地图边界研究

采用自编写的图像处理程序把中国地图处理成为边界点阵图，并根据点阵图每点的坐标位置，利用中国第1台单粒子束精确定位照射装置提供的单质子束在CR-39膜上几百μm×几百μm的范围内辐照并刻蚀出中国地图边界. 研究表明，该单粒子束精确定位照射装置计数准确(98%)，定位精确(平均误差小于3 μm)，辐照路径算法选择合理(近邻法)，预测值和实测值吻合程度高，可以满足刻蚀CR-39膜微图像和生物细胞辐照实验的要求.     

Development of Accurate/Advanced Radiotherapy Treatment Planning and Quality Assurance System (ARTS)

A prototype of accurate/advanced radiotherapy treatment planning and quality assurance system (ARTS) is developed and key technical issues related to the improvement of the treatment accuracy is studied. After a brief introduction to the prototype of ARTS, the advanced development in key technical issues is presented, including image data processing and human body modeling, fast and accurate hybrid dose calculation, multi-objective optimization of inverse planning, intelligent patient positioning, and dose verification.     

CAS-LIBB单粒子微束装置的微束入射点位置确定和系统定位精度研究

中国科学院离子束生物工程学重点实验室建成了一台单离子微束装置(CAS-LIBB)。CAS-LIBB装置由一台van de Graaff 静电加速器产生能量在2.0-3.0 MeV 的离子。该微束系统主要用于实施对生长在一种薄塑料膜上的细胞核的指定位置投射预定个数离子的技术。系统采用安装在束流末端的石英毛细玻璃管作为瞄准器来实现束流的微化并截取微束。细胞辐射实验中对细胞的识别和定位由一套计算机集成控制程序来完成。本文将从对微束的捕捉和定位（确定离子出口的准确位置），以及该微束系统的定位精度测量方面进行研究和讨论。当采用内径为5 μm,长度为980 μm的毛细管作瞄准器时，系统的定位精度为：91％的实验对象定位在距离预定位置2.4μm的范围内，98％的实验对象定位在距离预定位置3.6μm的范围内。     

碳离子辐射诱导秀丽隐杆线虫生殖细胞凋亡研究

重离子辐射具有独特的深度剂量分布和较高的相对生物学效应,被认为是理想的放疗手段。重离子的生物学效应在径迹形成过程中由多个物理参量共同决定,而这些物理参量和离子入射深度紧密相关,因此明确离子不同入射深度的生物学效应对重离子肿瘤放疗方案的设计和优化有着重要的理论和应用价值。使用兰州重离子研究装置HIRFL-CSRe 终端的碳离子束作为辐射源,以活体模式动物线虫作为实验对象,以线虫生殖细胞的凋亡水平作为生物学检测终点,研究了10 和20 Gy 碳离子辐射在辐射的入口、坪区和峰区的当代生物学效应和对后代个体基因组不稳定性的影响。结果表明:10 和20 Gy 碳离子辐射在三个不同的辐照区域内均显著增加了辐射当代的线虫生殖腺细胞的凋亡水平,并表现出一定的辐射区域和辐射剂量依赖性。同时,辐射诱导的后代个体基因组不稳定性也表现出一定的辐射区域和辐射剂量相关性。Heavy ion irradiation is a perfect means in radio-therapy due to its special depth dose distribution and high relative biological effects. The biological effects of heavy ion irradiation are determined by some major physical parameters, and vary along the tracks of heavy ions. Therefore, it is very significant for the tumor radio-therapy to investigate the biological effects along whole range of heavy ion radiation. In the present study, Caenorhabditis elegans, a model in vivo, was irradiated by carbon ion beams from HCRFL-CSRe, The level of germ cell apoptosis of worms was used as a checking endpoint for DNA damage, the effects of carbon irradiation located in the entrance, plateau and peak regions on the genomic instability of the irradiated worm and their progeny were detected. The results showed that the 10 and 20 Gy of carbon ion radiations led to the increased germ cell apoptosis in irradiated worms and these effects depend on the worm location along the range of carbon ions and the irradiation dosage. The results also suggested that heavy ion irradiation induced the up-regulated genomic instability in their progeny, and might be related to both the irradiation dose and the irradiated location.     

3D组织培养模型及其在辐射诱导旁效应研究中的应用

综述了3D细胞培养技术（TDCC）的发展, 3种主要的体外组织构建方法; 辐射诱导2D细胞产生旁效应的现象与机理; 人工构建的3D组织辐射后诱导的旁效应及其细胞间信号传导机理。 重离子（C离子）辐照作为一种重要的放疗工具, 对其辐射处理3D组织后诱导产生的旁效应进行了展望。 由于3D组织更接近人体细胞生长的真实环境, 因而以3D组织作为模型研究辐射诱导的旁效应, 对于辐射旁效应的防护和治疗可能具有重要的指导意义。 Compared with the cultured monolayer (2D) cells, three dimensional (3D) tissue could be more similar to the environment in vivo including the physical support, chemical factors, cell cell and cell matrix interaction and so on. With the development of three dimensional cell culture techniques (TDCC), 3D tissue is widely used in the areas of bystander effect research. This review focuses on introducing the TDCC method and its application in bystander effect research. First, the development process of 3D tissue culture method was introduced. Secondly, the induction of radiation induced bystander effects both in 2D cell and 3D tissue and its mechanisms were reviewed. Finally, because heavy ion (carbon ion beam) has been developed as a useful tool to cure solid cancer ,and the 3D tissue model is an ideal material to study the damages on body after being irradiated and to understand the underlying mechanisms, future study about heavy ion radiation inducing bystander effect in 3D tissue was discussed.     

Elaborate calibration procedure for cell irradiation at the CAS-LIBB single-particle microbeam

Single-particle microbeam is uniquely capable of precisely delivering a preset number of charged particles to individual cells or sub-cellular targets to be determined in vitro. It is crucial to find a reference point that relates the microbeam's location to the microscope's plane, and align individual targets at this reference point for cell irradiation. To choose an appropriate reference point, an approach based on analysing the intensity distribution of fluorescence in a thin scintillator excited by traversing particles is newly developed using the CAS-LIBB single-particle microbeam,which features decisive physical signification and sufficient resolution. As its bonus, this on-line analysis provides precise and fast response to the determination of beam profile and potentially optimizes the microbeam quality by further adjusting hardware setup.     

Single long-polymer translocation through a long pore

This paper theoretically studies the free energy and conformational entropy of a long polymer threading a long nanopore (n₀/N \ge 0.1) on external electric field. The polymer expanded model is built in this paper, that is, a single long polymer chain with N monomers (each of size a) threading a pore with n₀ monomers can be regarded as polymer with N+n_{0} monomers translocating a 2-dimension hole embedded in membrane. A theoretical approach is presented which explicitly takes into account the nucleation theory. Our calculations imply that, the structure of polymer changes more acutely than other situation, while its leading monomer reaches the second vacuum and its end monomer escapes the first vacuum. And it is also shown that the length scale of polymer and pore play a very important role for polymer translocation dynamics. The present model predicts that the translocation time depends on the chemical potential gradient and the property of the solvent on sides of pore to some extent.     

单粒子束细胞定位照射装置中微图像处理系统的设计

为了适应细胞辐射生物学基础研究的需要 ,按照生物实验的要求和装置的物理指标设计了实验室单粒子束装置的微图像处理系统。设计中遵循了科学性和经济性的原则 ,结构紧凑 ,性能稳定。结果表明 ,该系统达到了预期指标 ,解决了单粒子束装置精确定位辐射的这一关键技术 ,为细胞核的辐射实验提供了有力的工具     

植物个体远程辐射信号早期传递过程的研究体系创建

自2005年以来,活体中的远程辐射旁效应逐渐成为辐射生物学的研究热点,然而其早期信号传递过程的相关研究却鲜见报道,主要原因是由于早期信号传递过程研究所需的旁区与辐射区的自由分离与组合在动物模型上无法实现。本研究是基于植物个体可以切割和嫁接的特性,借鉴离体细胞培养基转移方法研究旁效应早期过程的思想,在植物个体上实现旁区与辐照区的"分离"与"组合",构建了一种研究个体远程辐射信号早期传递过程的植物实验体系。具体是以模式植物拟南芥菜转基因系(AtRAD54promoter∶∶GUS)为材料,同源重组修复相关基因AtRAD54表达水平为生物学检测终点,人为地将辐照区的组织(或器官)与旁区部分"分离"或"嫁接",通过测定旁区组织(或器官)的AtRAD54基因表达水平变化,研究其辐射信号传递的早期过程。该研究体系的创建为活体旁效应早期过程的研究提供了一种可行的研究方法。