Electron Transport in Tissue-Like Material

类组织材料中的电子传输

• 批准号: 6745625
• 负责人: LARRY H TOBUREN
• 金额: $ 19.56万
• 依托单位: EAST CAROLINA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6745625
• 关键词: DNA damage; bioenergetics; biophysics; biotransformation; cytotoxicity; electrical measurement; electron transport; electronic spectra; high energy particle; hydrogen ions; ionizing radiation; mass spectrometry; radiobiology; radiological health

DESCRIPTION (provided by applicant): This study will provide experimental data for understanding electron transport in the heterogeneous cellular environment and enable stringent tests of charged-particle track-structure simulation at the level of the underlying physics of energy transport, i.e., prior to assumptions of the nature of chemical and bio-chemical pathways leading to biological alterations. Much of our knowledge of the biological effectiveness of radiation to create DNA damage and cellular mutagenesis is based on Monte Carlo based simulations of the initial patterns of energy deposition. Because of a lack of detailed information on cross sections for interactions in the condensed phase, Monte Carlo simulations often use interaction cross sections derived from gas phase data, or from largely untested theoretical techniques. Uncertainties in these data might have detrimental effects on the accuracy by which patterns of energy deposition can be determined at microscopic dimensions such as are involved in the production of multiply damaged sites, damage clusters, in DNA. Since these codes provide the data upon which radiobiologic interpretations of dose-response relationships are based, they are a direct link to understanding the biological effects of radiation exposures, whether these exposures are environmental, diagnostic, or therapeutic. This work focuses on measurement of the spectra of electrons produced in thin films of condensed phase material by the transit of fast protons. Spectra, differential in ejected electron energy and emission angle, are measured following electron transport and their emergence from the material surface. The transport media of interest include water, hydrocarbons, oligonucleotides, oligopeptides and DNA in thin films and/or frozen as ices. The spectra will be compared to predictions of Monte Carlo codes that incorporate gas and/or condensed phase interaction cross sections to test the sensitivity and reliability of the codes to the details of the input data. This, the first direct test of the fundamental physics of electron transport in track simulation codes commonly used in radiobiology, will provide guidance for the application of these codes in radiobiology and strengthen confidence in our evolving understanding of the energy transport pathways leading to cellular damage and mutagenesis by ionizing radiation.

描述（由申请人提供）：本研究将为理解异质细胞环境中的电子传输提供实验数据，并在能量传输的基础物理水平上对带电粒子轨迹结构模拟进行严格的测试，即在假设导致生物改变的化学和生化途径的性质之前。我们对辐射产生DNA损伤和细胞突变的生物有效性的大部分知识都是基于基于蒙特卡罗的能量沉积初始模式的模拟。由于缺乏凝聚态相互作用截面的详细信息，蒙特卡罗模拟通常使用从气相数据导出的相互作用截面，或者使用未经测试的理论技术。这些数据中的不确定性可能会对能量沉积模式的准确性产生不利影响，这种模式可以在微观尺度上确定，例如涉及DNA中多个损伤位点和损伤簇的产生。由于这些代码提供了剂量-反应关系的放射生物学解释所依据的数据，因此它们是了解辐射照射的生物效应的直接联系，无论这些照射是环境的、诊断的还是治疗的。