外泌体检测在肿瘤放化疗中的应用

本文就外泌体的提取、富集、追踪及其在放化疗中的应用进展进行综述。目前外泌体提取与富集的主要方法包括超速离心法,层析法和色谱法等,外泌体可通过荧光素酶标记进行追踪。由于外泌体具有特异的表面标志物及其在体液中广泛存在的特点,使其成为潜在的肿瘤标志物之一。此外,外泌体在肿瘤的辐射敏感性与辐射损伤、肿瘤的靶向治疗和多重耐药等放化疗中的作用也日益受到关注。     

外泌体—电离辐射诱导旁效应的另一种机制

采用条件培养液转移的方法,以微核形成和克隆形成为终点,检测X-射线在H460非小细胞肺癌细胞中诱导经培养液介导的旁效应;采用差速离心法从未受照射和受照H460细胞培养液中提取、纯化外泌体,用透射电镜观察其形态,激光粒度仪分析其粒径分布,并用Western blot检测其标志蛋白hsp90β的表达。通过荧光探针共定位实验观察外泌体进入接收细胞的情况,采用结晶紫实验检测外泌体对接收细胞增殖的影响。结果表明:X-射线可在H460细胞中诱导经培养液介导的旁效应,表现为旁效应细胞的微核增加和克隆存活率下降;未受照射和受照细胞均分泌外泌体,但不同条件下细胞分泌外泌体的尺寸分布不同;当将外泌体加入到接收细胞时,外泌体可能通过膜融合的方式很快进入接收细胞,进而促进接收细胞的增殖;受照射H460细胞分泌的外泌体不影响接收细胞的克隆存活率,但增加接收细胞的微核形成率,并且这种现象在用RNA酶处理外泌体后消失。以上结果表明,受照射H460细胞分泌的外泌体可能是介导电离辐射旁效应的机制之一,并且其中RNA可能是介导电离辐射诱导旁效应的一种重要信号分子。     

血红蛋白和肌红蛋白穆斯堡尔谱研究

本文综述了在不同配位体键合下的血红蛋白和肌红蛋白、分离为α和β亚基的血红蛋白、无水血红蛋白、外磁场作用下的血红蛋白及单晶肌红蛋白的穆斯堡尔谱特征、理论解释以及在生物化学中的意义,并介绍了关     

γ、β放射云外照剂量估算

一、引言核设施在正常运行或事故条件下都将释出大量放射性气体或气溶胶。这些放射性气团(烟柱、烟团,通称为放射云)将通过各种途径(直接外照射、沉积于地面后的外照射,吸入或经食物链形成的体内照射)对工作人员和周围居民造成辐射危害。本文试就γ、β放射云外照剂量估算方法作一综述,以供参考。关于建筑物在γ烟云剂量估算中所提供的几何防护和屏蔽效应以及地面沉积放射性物质的外照剂量,由于篇幅所限,本文就不论述了。     

切尔诺贝利核电站事故及其影响

本文对切尔诺贝利核电站发生核事故过程与原因分析,以及事故的后果处理,事故对外环境的影响与对核电事业发展产生的反响,进行较系统地综述。同时应用事故树分析方法,初步分析了切尔诺贝利核电站发生的前因与后果,进而探讨核电站安全可靠性及其事故经验教训。     

模拟高盐高碱低中水平放射性废液水泥固化工艺的研究

针对高盐高碱低中水平放射性废液的特性,通过在普通硅酸盐水泥中掺入矿渣粉、粉煤灰和沸石作为矿物掺合料进行优化,获得固溶度大、低泌水率、流动性好、低核素浸出率的工艺配方,着重研究了水泥基材料组成、液灰比、盐浓度和促凝剂对扩展流动度、泌水率、凝结时间的影响规律。研究结果表明:矿物掺合料替代部分水泥可以发挥火山灰效应、减水效应,从而提高固化体对废液的包容量,改善拌合物的泌水、盐析现象;矿渣粉和粉煤灰有利于获得较高流动度的水泥拌合物,沸石可显著延长拌合物的凝结时间;随着高盐高碱低中水平放射性废液盐浓度的增加,扩展流动度减小,泌水率减小,凝结时间延长;三乙醇胺能有效缩短水泥固化的施工作业时间,掺量为1%时,PSFZ配方拌合物的初凝时间为262 min,终凝时间为302 min,可以满足施工作业要求。     

模拟高盐高碱低中水平放射性废液水泥固化工艺的研究北大核心CSCD

针对高盐高碱低中水平放射性废液的特性,通过在普通硅酸盐水泥中掺入矿渣粉、粉煤灰和沸石作为矿物掺合料进行优化,获得固溶度大、低泌水率、流动性好、低核素浸出率的工艺配方,着重研究了水泥基材料组成、液灰比、盐浓度和促凝剂对扩展流动度、泌水率、凝结时间的影响规律。研究结果表明:矿物掺合料替代部分水泥可以发挥火山灰效应、减水效应,从而提高固化体对废液的包容量,改善拌合物的泌水、盐析现象;矿渣粉和粉煤灰有利于获得较高流动度的水泥拌合物,沸石可显著延长拌合物的凝结时间;随着高盐高碱低中水平放射性废液盐浓度的增加,扩展流动度减小,泌水率减小,凝结时间延长;三乙醇胺能有效缩短水泥固化的施工作业时间,掺量为1%时,PSFZ配方拌合物的初凝时间为262 min,终凝时间为302 min,可以满足施工作业要求。     

先进快堆外套管材料铁素体/马氏体钢研究进展

介绍了快堆外套管材料的使用要求以及国内外快堆外套管材料的选用情况,论述了快堆中中子辐照对铁素体/马氏体钢的微观结构和力学性能的影响,并介绍了国产快堆外套管材料铁索体/马氏体钢的研发计划.铁索体/马氏体钢具有优异的抗辐照肿胀性能,T92钢作为第三代铁索体/马氏体钢同时具有良好的高温强度,被作为国产快堆外套管的首要候选材料...     

辐照技术研究

本文综述了辐照技术概况,包括它的任务、装置结构形式、监测和控制方法以及堆外实验室建设,从中探索辐照技术发展脉络和动向,调查应建立的有关技术和装备,可供开展辐照技术研究工作的参考.     

中子探测用有机闪烁体的研究进展

中子探测中,由于存在非弹性散射和慢中子捕获等作用,形成了n/γ混合辐射场,增加了中子探测的复杂性。有机闪烁体因其闪烁效率高、衰减时间短、探测效率高被广泛应用于中子探测。脉冲形状甄别是根据有机闪烁体中粒子衰减时间不同引起的脉冲形状差异来甄别n/γ的关键技术。传统脉冲形状甄别方法包括时域和频域甄别方法;近年来,各种机器学习技术也相继应用于n/γ甄别,并取得较好效果。为了更好地使用有机闪烁体和n/γ甄别方法进行中子探测,我们从有机闪烁体的发光机理、脉冲形状甄别原理、有机闪烁体类型及n/γ甄别方法等方面进行了较为全面的分析和综述,并总结了有机闪烁体和n/γ甄别方法的各种性能评价指标。最后,对有机闪烁体和n/γ甄别方法的发展趋势提出了展望。     

人因可靠性分析技术的研究进展与发展趋势

本文对人因可靠性分析方法进行综述。分别对人因可靠性分析的理论基础——人因失误机理、人因可靠性分析方法的关键要素以及现有的人因可靠性分析方法的研究现状进行了介绍和评析,指出了这些研究方法的不足,以及目前研究的热点和难点问题。总结并展望了人因可靠性分析方法的发展趋势。     

Applications of fault detection and diagnosis methods in nuclear power plants: A review

Nuclear power industries have increasing interest in using fault detection and diagnosis (FDD) methods to improve safety, reliability, and availability of nuclear power plants (NPP). A brief overview of FDD methods is presented in this paper. FDD methods are classified into model-based methods, data-driven methods, and signal-based methods. While practical applications of model-based methods are very limited, various data-driven methods and signal-based methods have been applied for monitoring key subsystems in NPPs. In this paper, six areas of such applications are considered. They are: instrument calibration monitoring, instrumentation channel dynamic performance monitoring, equipment monitoring, reactor core monitoring, loose part monitoring, and transient identification. The principles of using FDD methods in these applications are explained and recent studies of advanced FDD methods are examined. Popularity of FDD applications in NPPs will continuously increase as FDD theories advance and the safety and reliability requirement for NPP tightens     

Progress and prospects of calculation methods for radiation shielding

Progress in calculation methods for radiation shielding are reviewed based on the activities of research committees related to radiation shielding fields established in the Atomic Energy Society of Japan. A technological roadmap for the field of radiation shielding; progress and prospects for specific shielding calculation methods such as the Monte Carlo, discrete ordinate Sn transport, and simplified methods; and shielding experiments used to validate calculation methods are presented in this paper.     

Uncertainty analysis of system reliability and availability assessment

Uncertainty analysis of system reliability assessments with particular emphasis on commercial nuclear power generation stations have been investigated. Sources of uncertainty in reliability assessments are identified, and methods to account for their treatment are discussed. Available methods for determining uncertainties in system characteristics (such as unavailability) by synthesizing the known or assumed uncertainties in component characteristics (propagation of errors) are presented and compared.New or improved codes developed in this study are compared with previous methods. The use of a data base management system, common cause failure analysis and the influence of noncoherent structures in minimizing uncertainty in reliability assessment are discussed.     

Non-destructive detection and analysis of residual and loading stresses in thick-walled components

Components and systems are designated to withstand loads. These loads are primarily mechanical ones, additionally thermal, chemical and other ones. The constructed part has to support these loads with safety margins. Additionally, peak values for stresses have to be avoided. During the last ten years the theoretical background as well as the numerical evaluation were developed and introduced in practice. Especially finite-element methods at least for loading stresses are the common aid of the designing engineer. The experimental verification of calculated stresses and stress distributions fails up to now. There is no experimental measurement of stress at all. For strain measurements - restricted to elastic strains and to the surface region, not exceeding some ten micrometres - only the X-ray technique allows static and dynamic measurements. Strain variations by changes of loads or stresses can be measured with strain gages, optical holographical interferometry and other methods - also restricted to the surface only. Nothing is known about the volume-distribution of strains and stresses, and for scientists and engineers it is a surprising phenomenon how practicians here rely on theories and calculations. During the last five years several approaches were developed as non-destructive methods for strain/stress-measurements not only on the surface but in the interior, too. The state of the art is described in this contribution covering ultrasonic as well as micromagnetic methods. Examples are given from research results and applications in practice. The most important literature differentiated referring to physics, review contributions and applications is listed in an appendix.     

微波技术在碳纳米管合成与修饰中的应用

与传统方法相比，在碳纳米管合成、纯化及修饰中应用微波技术可以有效地促进反应，提高反应收率，缩短反应时间，抑制副反应的发生。本工作综述了微波技术在碳纳米管合成、纯化及修饰中的应用研究进展，并指出微波技术相对传统方法的优点。最后展望了今后的研究方向。     

核能公众接受性研究进展及发展趋势

在从美国三哩岛事故到日本福岛核事故的30多年时间里,世界各国研究人员一直在对核能公众接受性进行研究。本文对核能公众接受性的研究方法进行了梳理,分别对核能公众接受性研究方法的理论基础——社会调查方法、结构方程模型,以及现有的不同阶段核能公众接受性研究方法与其心理学本质进行了介绍和评析,按照研究深度及起始时间综合考虑,将现有研究方法分为3个阶段,并指出了这些研究方法对当下研究工作的意义,总结并展望了核能公众接受性研究方法的发展趋势。     

Design and analysis of multicavity prestressed concrete reactor vessels

A critical state-of-the-art review of multicavity prestressed concrete reactor vessel (PCRV) design and analysis practice is presented. Included are discussions of basic design concepts, the behavior of liners and penetrations, and the various tests required and/or employed to demonstrate acceptance of new vessel geometries and innovations. Brief reviews are given of the influences of design codes such as ACI/ASME Section III, Division 2, and BS4975; analysis methods including elastic, inelastic, and time-dependent techniques; the constituve equations that are essential to the satisfactory use of these techniques; and semi-empirical methods for calculating ultimate strengths of multicavity vessels.Tests conducted on liner plates, liner anchorage systems, and cooling tubes are reviewed together with the methods of analysis used in the design of anchorage systems. The adequacy and economy of present liner systems are considered and possible modifications in design are suggested.Design code requirements and methods of analysis for penetrations are discussed. The various types of closure designs that have been proposed and in some cases employed are evaluated on the basis of overall PCRV design philosophy. Several methods of prestressing PCRVs are considered with respect to relative advantages and disadvantages; existing overall vessel in-service inspection requirements are evaluated.