Theoretical studies of physical and chemical aspects of primary processes in fundamental radiobiology

基础放射生物学初级过程的物理和化学方面的理论研究

• 批准号: 9020-2010
• 负责人: JayGerin, JeanPaul
• 金额: $ 1.97万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=544584
• 关键词: Theoretical; studies; physical; chemical; aspects

If, nowadays, a panorama of the phenomena that underly the radiation chemistry of aqueous systems has reasonably been obtained in a number of cases, it appears that certain key aspects of this radiolysis are not yet fully resolved. This is especially true for the fundamental processes that link chemistry with the early physical interactions initiated by radiation. For example, recent fascinating observations have suggested the existence of new mechanisms in liquid-water radiolysis at very short times that now have to be identified and quantified. Bridging the gap in our understanding of this physicochemical interface is of obvious relevance to radiobiology and related science (e.g., free-radical biology) as liquid water is by far the most abundant constituent of biological cells. Knowledge of this "physicochemical" stage of radiolysis is central to a reliable description of the chemical nature and spatial distribution of the reactive species produced initially and precursors of radiobiological damage. This is also true for the radiolysis due to high linear energy transfer (LET) radiations, where it is critical to understand the complex nature of heavy-ion tracks (i.e., the "track structure") and their chemical effects (such as multiple ionization, Coulomb explosion, and thermal spike) for a number of practical reasons (e.g., hadrontherapy, space radiation effects). This is true as well when we want to account for the pivotal role played in the early stages of radiation chemistry by the numerous low-energy secondary electrons generated in the slowing of primary ionizing radiations, or for the fact that the aqueous medium itself is not continuous on a molecular scale. Using state-of-the-art stochastic Monte-Carlo methods and molecular dynamics calculations in combination with the knowledge gained from current experimental efforts, the proposed research program is aimed at designing experiment-and-theory based models to help advance our understanding of those challenging areas of the radiolysis of aqueous systems for which, we feel, a molecular-level characterization of the underlying chemistry is essential to produce a complete, accurate picture of this radiolysis. It is, without doubt, part of a major challenge in fundamental radiobiology.

如果如今，在许多情况下已经合理地获得了水性系统辐射化学基础的现象的全景，则似乎尚未完全解决这种辐射分解的某些关键方面。 对于将化学反应与辐射引发的早期物理相互作用联系起来的基本过程尤其如此。 例如，最近的引人入胜的观察表明，在很短的时间内，必须识别和量化液 - 水辐射溶解中存在新机制。在我们对这种理化界面的理解中弥合差距与放射生物学和相关科学（例如自由基生物学）显然是相关的，因为液态水是迄今为止最丰富的生物细胞组成的。对这种“物理化学”辐射分解阶段的了解对于最初产生的反应性物种的化学性质和空间分布的可靠描述和放射生物学损害的前体是至关重要的。由于高线性能量传递（LET）辐射引起的辐射溶解也是如此，在这种情况下，重要的是，了解重离子轨道（即“轨道结构”）的复杂性质及其化学作用（例如多种实际原因（例如，Hadrontherpherpherapy，Space Hadiation效果），这一点至关重要。当我们想通过在辐射化学的早期阶段来说明在辐射化学的早期阶段所起的关键作用，这也是正确的，这是在初级电离辐射放慢的速度下产生的许多低能二级电子，或者因为水培养基本身不是在分子尺度上连续的事实。使用最新的随机蒙特卡洛方法和分子动力学计算，结合当前实验努力所获得的知识，旨在设计基于实验和理论的模型，以帮助我们对水面系统的辐射分析的理解，以帮助我们对水平系统的辐射范围进行挑战，使我们感到，我们感觉到了综合化学效果的精确性，这些化学效果是一项完整的化学效果。毫无疑问，这是放射生物学基本挑战的一部分。