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

基础放射生物学中初级过程的物理和化学方面的理论研究

• 批准号: RGPIN-2022-03972
• 负责人: JayGerin, JeanPaul
• 金额: $ 2.04万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760618
• 关键词: Theoretical; studies; physical; chemical; aspects

Understanding radiation-induced processes in water is of crucial importance to many areas of basic/applied radiobiological physics and chemistry, medicine, and a variety of technological/industrial applications, including the nuclear industry. Despite decades of efforts to better understand the basic phenomena underlying the radiation chemistry of water, certain quantitative aspects of this radiolysis remain unresolved. This is especially true for ultrafast processes that link chemistry and physics following the initial energy deposition. Since water is by far the most abundant component of biological cells, understanding the interface between radiation physics and radiation chemistry of water is of obvious relevance to fundamental radiobiology. In fact, a detailed knowledge of the early physical and chemical stages of radiation action (e.g., "breaking the picosecond barrier") is of utmost importance for a reliable description of the chemical nature and the highly nonhomogeneous spatial distribution of all reactive species that are created on the (sub-) picosecond timescale and are involved as precursors to radiobiological damage     Theoretical in nature, this project, therefore, focuses primarily on the characterization of the "physicochemical stage" of radiation action. There are, in particular, three open questions that we wish to investigate over the next five years under an NSERC Discovery Grant: (i) the physical behavior of the numerous low-energy (<30 eV) electrons, generated as the radiation passes through, and their pivotal role as precursors of hydrated electrons on the transient subsequent chemistry in the radiation track development; (ii) high-dose-rate effects in the face of the considerable challenges in finding the mechanisms of the "FLASH effect", a new revolutionary modality in radiotherapy; and (iii) the fact that the aqueous medium itself is not continuous at the molecular level (all track physics programs have so far viewed water as a continuum). For this, we will attempt to generate a track in a way that recognizes the molecular nature of the target medium.     Taken together, the proposed research program will use state-of-the-art Monte Carlo methods and molecular dynamics calculations in combination with the findings from current experimental efforts to design experiment-and-theory based models to advance our knowledge of the radiolysis of (dilute and concentrated) aqueous systems. We strongly believe that early-time characterization of the underlying chemistry at the molecular level is crucial to get a complete and accurate picture of this radiolysis. It is, without a doubt, part of a major challenge in fundamental radiobiology with the long-term goal of gaining a global understanding of the effects of radiation in biological systems and using this knowledge to increase the therapeutic and diagnostic efficiency of radiation.

对于许多基本/应用放射生物学物理学和化学，医学以及包括核工业在内的许多技术/工业应用，了解辐射引起的水的过程至关重要。尽管几十年来，要更好地理解水的辐射化学基础的基本现象，但这种放射分解的某些定量方面仍未解决。对于在初始能量沉积后连接化学和物理的超快过程尤其如此。由于水是生物细胞中最丰富的成分，因此了解辐射物理学和水的辐射化学之间的界面与基本放射生物学显然相关。实际上，对辐射动作的早期物理和化学阶段的详细知识（例如，“破坏皮秒障碍物”）对于可靠的化学性质和高度非综合性空间分布的可靠描述至关重要放射性的“物理化学阶段”。特别是，我们希望在未来五年内根据NSERC Discovery Grant进行三个空旷的问题：（i）随着辐射通过时产生的众多低能量（<30 eV）电子的身体行为，以及它们作为在辐射轨迹开发中暂时性化学上的水合电子的前体的关键作用； （ii）面对考虑挑战的高剂量率效应在寻找“闪光效应”的机制，这是一种新的放射疗法的革命性方式； （iii）水培养基本身在分子水平上不是连续的事实（迄今为止，所有轨道物理学计划都将水视为连续性）。为此，我们将尝试以识别目标介质的分子性质的方式生成轨道。综上所述，拟议的研究计划将使用最先进的蒙特卡洛方法和分子动力学计算，并结合当前实验努力的发现，以设计基于实验和理论的模型，以促进我们对（稀释和浓缩）水性系统的放射分解的了解。我们坚信，分子水平的基础化学的早期表征对于获得这种辐射溶解的完整而准确的情况至关重要。毫无疑问，这是基本放射生物学的主要挑战的一部分，其长期目标是全球了解辐射在生物系统中的影响，并利用这些知识来提高辐射的治疗和诊断效率。