Collaborative Research: Experimental determination of trace element diffusion rates in tooth enamel

合作研究：牙釉质中微量元素扩散速率的实验测定

• 批准号: 1561027
• 负责人: Matthew Kohn
• 金额: $ 17.07万
• 依托单位: Boise State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1561027&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; determination; trace

This project will investigate the rate of uptake of trace elements like barium, strontium, lead and the rare-earth elements (selected elements from lanthanum to lutetium) into tooth enamel. This project requires a key analytical technique "Secondary Ion Mass Spectrometry (SIMS)" because the spatial scale of measurement is so small. This research is important for understanding how trace elements are taken up in the human body and their fidelity in distinguishing individuals on timescales ranging from years to millions of years. The work will have implications for paleontology, archeology, toxicology and forensics, including the litigation of fossil theft. This funding will support the research and training of a PhD student. This research will be used to leverage educational opportunities for non-scientists in the Boise region and connect researchers unaware of how all areas of microchemical research can benefit from SIMS, a tool that is most commonly applied to semiconductors.The central focus of this project is to critically evaluate rates of diffusion of numerous trace elements in natural dental enamel. The research has been formulated to answer three main questions: How do diffusivities (D's) of trace elements in enamel depend on 1) charge vs. ionic radius and partitioning? 2) enamel orientation and enamel type? 3) fossilization state? To address these questions, uptake experiments will be conducted over a range of temperatures (4°, 20° and 37 °C) for a range of ions and ionic radii. D's will be measured in different directions for the two main enamel types in mammals - radial and decussate. Measurements in fossil enamel will be compared with similar measurements we make in modern enamel. The data will be inverted using standard diffusion equations, and natural datasets will be evaluated for their consistency (or not) with diffusion-limited uptake. The results will broadly constrain REE, uranium and alkaline element partition coefficients, which will improve models of diffusion rate and uptake of these geochemically- and toxicologically important elements. All data will be published rapidly in accessible international journals and/or archived in on-line geochemical databases. A PhD student will participate in a SIMS workshop, helping develop a community of SIMS users and present her work on fossils and fossilization to elementary school children and the public through established outreach programs.

该项目将研究痕量元素的吸收速率，例如钡，锶，铅和稀土元素（从兰萨姆到lutetium的选定元素）进入牙齿搪瓷。该项目需要一种关键的分析技术“次级离子质谱法（SIMS）”，因为测量的空间尺度太小。这项研究对于了解如何在人体中占据痕量要素及其在分区的时间尺度范围从年到数百万年的时间表上的忠诚元素很重要。这项工作将对古生物学，考古学，毒理学和取证，包括化石盗窃案的诉讼。这笔资金将支持博士生的研究和培训。这项研究将用于利用博伊西地区的非科学家的教育机会，并将研究人员不知道微化学研究的所有领域如何受益于SIMS，该工具最常用于该项目的主要重点。该项目的主要重点是严格评估天然牙齿牙釉质中众多微量元素差异的差异。该研究已被制定为回答三个主要问题：搪瓷中微量元素的差异（D的差异（D）如何取决于1）电荷与离子半径和分区？ 2）搪瓷方向和搪瓷类型？ 3）聚焦状态？为了解决这些问题，将在一系列离子和离子半径的一系列温度（4°，20°和37°C）上进行吸收实验。 D的哺乳动物和决定的两种主要牙釉质类型将以不同的方向测量。化石搪瓷的测量将与我们在现代搪瓷中进行的类似测量进行比较。数据将使用标准扩散方程倒置，并且将对它们的一致性（或不使用扩散限制的摄取）进行评估。结果将广泛限制REE，铀和酒精元素元素分区系数，这将改善这些地球化学上重要和毒理学重要元素的扩散速率的模型。所有数据将在可访问的国际期刊和/或在线地球化学数据库中迅速发布。博士生将参加模拟人生的研讨会，帮助开发模拟人生的用户社区，并通过既定的外展计划向小学生和公众展示她的化石工作。