基于现代光谱检测技术研究温度等关键因素对死亡时间推断的影响

受害人的死亡时间与案发时间直接关联，推断死者的确切死亡时间在法医学实践中有着非凡的侦查与破案价值，但该课题长期难以得到有效解决。本课题组先后在二个国家自然科学基金支持下，创新运用FTIR光谱及生物电阻抗探测技术，系统观察了大鼠死后一周时间内主要内脏组织于多个不同温度、湿度、死亡原因等可变条件下的光谱学变化规律，并已筛选出多个有价值的吸收峰比指标，据此建立的一系列多元回归方程已经完全可用于稳定环境条件下死亡时间的推断，但可变环境下的光谱变化至今仍然无法获得满意数据。本次申请项目将以影响光谱指标最主要的因素"温度变化"为突破口，结合已有的死亡时间推断方法，通过室外自然条件下小间隔连续性动物实验检测，找出可变温度环境下的生物光谱学变化规律及其发生机制；同时批量收集并检测来自现场的人尸体标本，以最终建立可用之于辅助法医学检案的人体死亡时间推断光谱数据库为目标，把死亡时间推断的研究工作向前推进一步。

The dead time of victims in a scene is associated tightly with the crime time, so it is a critical factor in the forensic practice and legal investigation. But for a long time, forensic pathologists have not figured out the correct way to judge the postmortem interval(PMI). Our team was funded twice successfully by the NSFC using innovatively the Fourier infrared spectroscopy and bio-electric impedance to detect the spectroscopic changes of 7 kinds of tissues in rats for 168 hours after the death at the three different temperature levels, two different humidity levels, three different causes of death. We have harvested a series of mathematical equations based on much valuable absorption peak ratios which can be used to judge the PMI in room temperature conditions. However, unstable environment is very complex, so far,even a lot of work was done,medicolegists can still not get the right data. This proposal will focus on the "temperature change" as a breakthrough, meanwhile combined with the traditional method, proceeding a large animal experiments in outdoor environment. Depending on the related theory of physics and chemistry, we try to find out the regular pattern of spectroscopic peak ratios related the temperature change and its mechanism. At the same time, batch collected and testing human specimens from crime scene and finally establish available database which will be used in medicolegal work. Hopefully the plan can promote strong progress of this field.