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.

了解水系统中辐射引起的过程对于基础和应用放射生物物理和化学、医学以及各种技术和工业应用的许多领域至关重要。在许多情况下已经获得了水和水溶液的化学性质，但似乎这种辐射分解的某些定量方面尚未完全解决，对于在能量沉积后的最初几皮秒内将化学和物理联系起来的超快过程尤其如此。辐射物理学和辐射化学之间的界面（即“突破皮秒屏障”）与基础放射生物学和相关科学具有明显的相关性，因为液态水是迄今为止生物细胞和组织中最丰富的成分（活细胞含有约 70-85最重要的是，它对于可靠地描述在（亚）皮秒时间尺度上产生并作为放射性生物损伤前体的所有反应物质的化学性质和高度不均匀的空间分布至关重要。这种理解对于创建可靠的预测模型也至关重要，本项目将重点关注辐射作用的物理化学阶段（<1 ps）的表征，特别是我们希望解决的一个难题。在 NSERC 发现资助下的未来五年，研究人员将研究在初级电离辐射减慢过程中产生的大量低能（<30 eV）二次电子的物理行为以及它们可以发挥的关键作用，例如我们希望研究的另一个非常重要的领域是水介质本身在分子尺度上不连续（迄今为止所有轨道物理程序都考虑了水）。作为一个连续体）。我们将尝试使用最先进的随机蒙特卡罗方法和分子动力学来生成一条能够识别目标介质分子性质的轨迹。结合当前实验工作中获得的知识进行计算，拟议的研究计划旨在设计基于实验和理论的模型，以增进我们对（稀释和浓缩）水系统辐射分解的了解，我们认为，早期-现在，基础化学的分子水平表征对于产生这种放射分解的完整、准确的图像至关重要，毫无疑问，这是基础放射生物学的一项重大挑战的一部分，我们的长期目标是实现全球对放射分解的理解。效果辐射在生物系统中的应用，并应用这些知识来提高辐射的治疗和诊断效率。