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: RGPIN-2015-06100
• 负责人: JayGerin, JeanPaul
• 金额: $ 3.35万
• 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: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689375
• 关键词: Theoretical; studies; physical; chemical; aspects

An understanding of radiation-induced processes in aqueous systems is vital to many areas of basic and applied radiobiological physics and chemistry, medicine, and in a variety of technological and industrial applications. If, nowadays, a general understanding of the phenomena that underline the radiation chemistry of water and aqueous solutions has been obtained in many cases, it appears that certain quantitative aspects of this radiolysis are not yet fully resolved. This is especially true forultrafast processes that link chemistry and physics in the first few picoseconds following energy deposition. Understanding this interface between radiation physics and radiation chemistry (i.e., "breaking the picosecond barrier") is of obvious relevance to fundamental radiobiology and related science as liquid water is by far the most abundant constituent of biological cells and tissue (living cells contain ~70-85% water by weight). Most importantly, it is central to a reliable description of the chemical nature and highly nonhomogeneous spatial distribution of all reactive species created on the (sub) picosecond time scale and involved as precursors of radiobiological damage. This understanding is also critical to creating reliable predictive models. Of a theoretical nature, the present project will focus on the characterization of the physicochemical stage of radiation action (<1 ps). In particular, one difficult problem that we wish to address in the next five years under an NSERC Discovery Grant is the physical behavior of the numerous low-energy (<30 eV) secondary electrons generated in the slowing of primary ionizing radiations and the pivotal role they can have, as precursors of hydrated electrons, on the transient ensuing chemistry in the radiation track development. Another aera of great importance that we wish to examine is the fact that the aqueous medium itself is not continuous on a molecular scale (all track physics programs have hitherto considered water as a continuum). We will attempt to generate a track in a manner that recognizes the molecular nature of the target medium. 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 aims to design experiment-and-theory based models to advance our knowledge of the radiolysis of (dilute and concentrated) aqueous systems for which, we feel, an early-time, 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 where our long-term goal is to achieve a global comprehension of the effects of radiation in biological systems and to apply this knowledge to enhance the therapeutic and diagnostic efficiency of radiation.

对辐射系统中辐射诱导的过程的理解对于许多基本和应用放射生物学物理学和化学，医学以及各种技术和工业应用的领域至关重要。如今，在许多情况下已经获得了强调水和水溶液辐射化学的现象的一般理解，似乎该辐射溶解的某些定量方面尚未完全解决。对于能量沉积后的前几个皮秒上连接化学和物理学的超快过程尤其如此。了解辐射物理学和辐射化学之间的这种接口（即“打破皮秒屏障”）与基本放射性生物学和相关科学显然相关，因为液态水是迄今为止最丰富的生物细胞和组织（生物水的含量最丰富）（活细胞含有〜70-85％的水）。最重要的是，它是对化学性质的可靠描述和在（亚）皮秒级时量表上产生的所有反应性物种的高度非均匀空间分布的核心，并作为放射生物学损害的前体涉及。这种理解对于创建可靠的预测模型也至关重要。在理论性质中，本项目将集中于放射性动作的物理阶段（<1 ps）的表征。特别是，我们希望在未来五年内提出的一个困难问题是在NSERC发现赠款下要解决的一个问题是在降低初级电离辐射的减慢速度和它们可以具有的枢纽作用时，作为在辐射轨道开发的瞬态化学上，它们可以具有的临时电子的预电向作用，这些次要电子的物理行为和它们可以具有的关键作用。我们希望研究的另一个非常重要的AERA是，水介质本身在分子尺度上并不连续（所有轨道物理学计划都将水视为连续性）。我们将尝试以识别目标介质的分子性质的方式生成轨道。使用最先进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，拟议的研究计划旨在设计基于实验和理论的模型，以促进我们对（稀释和浓缩）水性系统的辐射分解的知识，为此，我们认为，早期，早期的分子表现效果的化学表现效果是必不可少的。毫无疑问，这是基本放射生物学的主要挑战的一部分，我们的长期目标是全球理解辐射在生物系统中的影响，并应用这些知识以提高辐射的治疗和诊断效率。