低剂量率下高线性能量转移碳离子束辐照人类唾液腺细胞的存活效应

利用日本千叶重离子医用加速器HIMAC提供的碳离子束,对人类唾液腺细胞(HSG)在剂量率为0.5Gy/h的低剂量率条件下进行了辐照,运用标准的克隆形成法得到了3种不同剂量平均线性能量转移(LET)碳离子束辐照HSG细胞的剂量存活效应.与先前HSG细胞在治癌剂量率(1￣5Gy/min)下对相近剂量平均LET碳离子束辐照的剂量存活效应数据相比,HSG细胞对高LET碳离子束辐射表现出明显的剂量率效应.为在相同条件下得到碳离子束对HSG细胞的相对生物学效应(RBE),利用60Co-#射线在剂量率为0.5Gy/h的条件下辐照了HSG细胞,得到该细胞系对低LET射线响应的剂量存活效应.与先前在治癌剂量率下得到的RBE值相比,低剂量率条件下得到的RBE值总体减小.由实验发现的剂量率效应及低剂量率条件下RBE值的减小,表明由高LET碳离子束造成的辐射损伤在低剂量率条件下也存在着显著的修复效应.据此,对辐射造成细胞致死的原因进行了探讨

A theoretical perspective of an e-diplomacy maturity framework

Diplomacy forms the basis of interaction for countries throughout the globe, while propelling cordial international relations in a wide array of socio-cultural and political. This research outlines an innovative conceptual structure for examining the maturity and feasibility of e-diplomacy. The proposed e-diplomacy maturity framework is a derivative of literary analysis on e-government maturity model, ICT growth of stage theories, coupled with theoretical information and practical features of diplomacy. The e-diplomacy maturity model constitutes variables like the degree of complexity and level of interactivity. Integration of the two variables results in varying phases of the framework. Challenges implicated in the e-diplomacy maturity framework include: sensitivity hence discretionary nature of diplomatic elements, setbacks in organizational structure, and communication impediments on the part of diplomats, as well as, politico-economic concerns and socio-cultural tendencies of various parties