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Bystander effect in human hepatoma HepG2 cells caused by medium transfers at different times after high-LET carbon ion irradiation
No full textAlthough radiation-induced bystander effects have been well documented in a variety of biological systems, whether irradiated cells have the ability to generate bystander signaling persistently is still unclear and the clinical relevance of bystander effects in radiotherapy remains to be elucidated. This study examines tumor cellular bystander response to autologous medium from cell culture irradiated with high-linear energy transfer (LET) heavy ions at a therapeutically relevant dose in terms of clonogenic cell survival. In vitro experiments were performed using human hepatoma HepG2 cell line exposed to 100 key/mu m carbon ions at a dose of 2 Gy. Two different periods (2 and 12 h) after irradiation, irradiated cell conditioned medium (ICCM) and replenished fresh medium were harvested and then transferred to unirradiated bystander cells. Cellular bystander responses were measured with the different medium transfer protocols. Significant higher survival fractions of unirradiated cells receiving the media from the irradiated cultures at the different times post-irradiation than those of the control were observed. Even replenishing fresh medium for unirradiated cells which had been exposed to the ICCM for 12 h could not prevent the bystander cells from the increased survival fraction. These results suggest that the irradiated cells could release unidentified signal factor(s), which induced the increase in survival fraction for the unirradiated bystander cells, into the media sustainedly and the carbon ions triggered a cascade of signaling events in the irradiated cells rather than secreting the soluble signal factor(s) just at a short period after irradiation. Based on the observations in this study, the importance of bystander effect in clinical radiotherapy was discussed and incorporating the bystander effect into the current radiobiological models, which are applicable to heavy ion radiotherapy, is needed urgently. (C) 2010 Elsevier B.V. All rights reserved
Particle-in-cell mode beam dynamics simulation of the low energy beam transport for the SSC-linac injector
No full textA new SSC-linac system (injector into separated sector cyclotron) is being designed in the HIRFL (heavy ion research facility of Lanzhou). As part of SSC-Linac, the LEBT (low energy beam transport) consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIG (particle-in-cell) code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ (radio frequency quadrupole) for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.National NatuLanzhou Univ, Sch Nucl Sci & Technol, Lanzhou 730000, Peoples R Chinaral Science Foundation of Chin
高频变谐波同步加速的方法及其控制装置
No full text本发明涉及质子-重离子治癌同步加速器中加速离子的方法技术领域，具体涉及一种高频变谐波同步加速的方法及其控制装置。其采用与高频变谐波同步加速相对应的控制装置，并利用同步加速器中的高频腔首先采用频率等于储存离子回旋频率的高次谐波(2次或4次)的高频电场加速离子，当加速至一定的中间能量时，将高频腔的高频电场频率改变为储存离子回旋频率的低次谐波(1次或2次)，继续加速离子直至临床所需要的能量。在高频腔工作频率范围内，采用高频变谐波加速技术，避免了铁氧体加载高频系统宽频带加速时低端扩展的困难。其在较窄的高频腔工作频率范围的基础上，拓宽俘获和加速离子的能量范围，实现人体不同深度肿瘤的离子束照射治疗对束流能量的要求
EXPERIENCE OF CYCLOTRON OPERATION WITH BEAM SHARING AT TSL
No full textFollowing a reorientation in 2005/2006, the focus of<br />activities at TSL was shifted from nuclear physics to<br />proton therapy and radiation testing with protons and<br />neutrons. In order to use the beam as efficient as possible<br />beam sharing is employed. The paper describes the<br />development of a range of control system utilities, for<br />example switching of the beam between users by the<br />principal user instead of being controlled via a cyclotron<br />operator.IMP;Chinese Academy of Science
重离子治癌相关研究；Researches Related to Heavy Ion Cancer Therapy
No full text癌症是现代医学的难题,一直危害着人类的健康。放射治疗是癌症治疗的有效手段之一。由于重离子束在物理学和生物学性质上所具有的优势,它已成为放疗用的最佳射线。简述了重离子治癌的发展历程、现状以及特点,详细讨论了在医学物理和放射生物学研究领域值得关注的若干热点问题
在核实验仪器中的嵌入式微机选型
No full text简要介绍了在核物理实验设备研制和改进项目中,采用嵌入式微机的必要性和优点。根据系统改进的具体要求,调研并在实验室对几款市场上的嵌入式微机进行了具体性能测试,从而选择了具有超低功耗的x86架构嵌入式微机作为物理实验仪器中的控制器核心部件,并期望在高速数据采集和电控系统中得到应用
双奇核~(170)Re高自旋转动带分析(英文)；Analysis of High-spin Rotational Band in Odd-odd ~(170)Re
No full text通过重离子熔合蒸发反应142Nd(32S,1p3nγ)170Re布居了缺中子双奇核170Re的高自旋激发态,识别出了该核的一条转动带并建议了其组态为πh1/2 νi13/2。基于对同中子素能级系统性、旋称反转系统性、带内B(M1)/B(E2)、准粒子Routhians、动力学转动惯量和Total Routhian Surface(TRS)等带结构特征的详细分析和讨论,进一步确认了对A=170核区目前最缺中子双奇核高自旋转动带组态、宇称和自旋值的指定
兰州重离子加速器团簇内靶装置控制系统设计；Design of a Control System for HIRFL-CSRe Internal Target Facility in Lanzhou
No full text介绍了兰州重离子加速器冷却储存环(HIRFL-CSR)的实验环(CSRe)团簇内靶装置控制系统的设计。该内靶系统由多种设备构成,包括喷嘴测温与加热控制子系统、真空与阀门监测/控制子系统、分子泵监测与控制子系统、数据处理与流程软件子系统等部分。该系统在内靶实验中工作状态良好,满足了内靶实验的需求。在该控制系统的支持下,2010年1月第一轮辐射电子俘获物理实验顺利完成
空间辐射生物学研究进展；Research Progress on Space Radiation Biology
No full text空间电离辐射尤其是高能带电粒子辐射可造成生物机体的严重损伤,是载人航天飞行的关键性限制因素之一。研究表明,带电粒子的生物学效应与其性质、剂量以及不同生物学终点有关;此外,微重力环境可能会影响空间辐射生物学效应。从多年来的空间搭载实验研究和地基模拟实验研究两个方面,综述了空间辐射的生物损伤效应及其与微重力环境复合作用的生物效应