尸体腐败程度与死亡经过时间的实验研究

为了找出推测死亡经过时间的客观依据,应用健康的苏白猪为实验模型,进行尸体腐败程度与死亡经过时间研究,将模型分别放置在室内、室外及地下三个环境中,让尸体在自然的环境中发生腐败,详细记录尸体腐败所表现的现象,特别是腐败气体所产生的张力。实验发现,尸体腐败至软组织与骨骼全部分离、以及腐败残留物质的完全消失,与温度、湿度、降雨量、尸体与地面倾斜度、昆虫的寄生等有明显的关系。所得数据,为死亡经过时间的推测,积累了重要的参考依据。     

尸体腐败程序与死亡经过时间的实验研究

为了找出推测死亡经过时间的客观依据,应用健康的苏白猪为实验模型,进行了尸体腐败程度与死亡经过时间研究,将模型分别放置在室内、室外及地下三个环境中,让尸体在自然的环境中发生腐败,详细记录尸体腐败所表现的现象,特别是腐败气体所产生的张力。发现,尸体腐败至办组织与有骼全部分离、以及腐败残留物质的完全消失,与温度１温度、降雨量、尸体与地面倾斜度、昆虫的寄生等有明显的关系。所得数据,为死亡经过时间的推测,     

尸体腐败微生物的研究进展

法医学死亡时间的推断已从传统的病理学诊断转变为多证据佐证的模式。自然状态下尸体腐败过程受多因素影响,其中微生物是影响尸体腐败的敏感指标,因此,尸体上微生物群落的结构的变化有可能成为死亡时间推断的新依据。本文综述了自然状态下尸体上微生物群落的演替特征及影响因素,并列举了微生物的取样、储存及检测方法,希望能为法医微生物学的研究及实践提供参考。     

四季尸食性蝇类参与尸体软组织分解过程初探

目的观察了解四季尸食性蝇类参与尸体软组织分解过程的规律。方法在室外自然环境中设置尸体,分别在春、夏、秋、冬季节,用肉眼观察尸体每一时段的变化及尸食性蝇类参与尸体分解的现象。结果在4个不同的季节中,尸体软组织分解过程中尸食性蝇类参与种类及虫态各不相同。通过观察获得尸体变化各阶段的大体历期,尸体变化各阶段常见的尸食性蝇种及虫态资料。结论观察所得资料可为推测晚期尸体的死亡时间提供参考。     

尸体腐败研究亟待解决的几个问题

尸体腐败是指尸体受腐败菌作用，组织分解消失的过程。由于法医学对尸体腐败的研究不够多，尤其是实验性的研究不多，故腐败发展的程度与死后时间的相关规律还远未完全被人们所掌握，要据此推测出较准确的死后时间比较困难。尸体腐败最早的表现是在右下腹部皮肤出现污绿色斑，即腐败绿斑，简称尸绿。春秋季节的尸体，通常在死后24小时左右出现[1]，夏季10小时左右出现，春秋季节1～2天，冬季3～4天[2]；尸绿发展至全身（尸）有需要10～12天的[3]，也有仅需3~5天的[4]。腐败时产生气体，腐败气体在各组织器官中不断增多形成腐败气肿，使尸体…     

利用绯颜裸金蝇(双翅目,丽蝇科)在中国西南地区进行死亡时间推断1例（英文）

在人类尸体上发现的昆虫样本可为最短死亡时间(minimum postmortem interval,PMImin)推断提供重要信息。在中国重庆某废弃工厂里发现了一具女性尸体,经现场勘验和尸体检验确认为他杀死亡。由于死者不同部位的腐败程度不一致,难以确定死亡时间。通过形态学观察和线粒体DNA测序分析,确定尸体上的昆虫样本为绯颜裸金蝇。根据该种属的发育速度资料,尸体的PMImin推断为452 h。死亡时间的准确推断为案件侦查和犯罪嫌疑人起诉提供了重要的昆虫学证据,证实了在该区域特定种属的昆虫学证据对准确死亡时间的推断具有较高的实用价值,尤其适合晚期腐败尸体的PMI推断。     

根据超生反应推断死亡时间的研究概况

死亡时间推断是指通过一定的手段推测尸体从检查时距死亡时刻的间隔时间(postmortem interval),是法医实际工作中首先要解决的重要任务之一。准确推断死亡时间,在很大程度上能为刑事案件的侦破提供重要的线索,划定侦查范围,确定犯罪嫌疑人有无作案时间乃至确定案件性质和阐明作案过程均有重要意义。近年来,我国法医工作者在超生反应、法庭昆虫学、内皮细胞活性、核仁区噬银蛋白形态学变化、肌肉酶活性、骨骼肌运动终板乙酰胆碱酯酶活性、玻璃体液化学物质成分的改变、肝细胞自溶超微结构、家兔死后红细胞内钾离子含量、尸体腐败程度、植物根…     

根据食尸性蝇类推断死亡时间的研究进展

法医昆虫学是应用昆虫学知识解决法医实践中所遇到的相关问题的一门科学。食尸性蝇类在尸体的腐败分解中发挥着重要的作用,运用食尸性蝇类的特点可以更准确进行死亡时间推断,为侦查破案提供线索。本文对依据食尸性蝇类推断死亡时间的方法进行综述,以期为后续的研究与实践应用参考和借鉴。     

“破溃点”——尸体腐败过程中腹腔自然破裂时刻的实验研究

目的 本文聚焦腐败这一重要晚期尸体现象,以期找到更客观的晚期尸体现象关键事件或特征节点,为准确评估尸体腐败程度、进而推断死亡时间（PMI）提供有力依据。方法 本研究通过对晚期尸体现象进行观测,对尸体腐败过程中肠道和尸坑土微生物菌群结构变化,以及尸坑土理化性质的检测,从宏观和微观两个层面,分析尸体腐败过程中腹腔自然破裂这一关键事件发生的时刻前后变化。结果 研究发现尸体腹腔自然破裂前后,腐败现象和相关微生物菌群结构以及环境理化性质三方面均有显著差异,且可观测性强,可以通过法医学观察、生物学和理化相关检测手段准确判断。本研究将这一关键事件发生时刻命名为“破溃点”。结论 本文认为“破溃点”可以作为法医实践中尸体腐败程度评估的重要节点,也可以作为基于微生物菌群结构变化等表征构建PMI推断模型时的分界点,分段构建模型以提升PMI推断模型的准确度。     

13例腐败尸体死亡时间推断错误原因分析

死亡时间推断有十分重要的法医学意义,对查明案件真相常常起到关键作用。在实践中,腐败尸体的死亡时间推断历来是法医学的难点,推断的死亡时间同实际死亡时间存在误差常是难以避免的,但若误差较大,对案件的侦办就失去了实际意义,甚至会误导案件的侦查方向,产生冤假错案。此时的“误差”就应称为错误。本文对13例腐败尸体死亡时间错误推断的原因进行回顾性分析,并就腐败尸体死亡时间推断应注意的问题进行讨论,旨在提高基层法医工作者对腐败尸体某些尸体现象的认识和重视。1案例资料1.1一般资料13例腐败尸体案例来自于南京市公安局法医中心199…     

Mapping the lateral extent of human cadaver decomposition with soil chemistry

Soil below decomposing cadavers may have a different lateral spatial extent depending upon whether scavengers have access to the human cadaver or not. We examined the lateral spatial extent of decomposition products to a depth of 7cm of soils beneath two decomposing corpses, one in which the subject was autopsied, unclothed and placed under a wire cage to restrict scavenger access and one in which the subject was not autopsied, unclothed and exposed to scavengers. The two bodies had accumulated degree days (ADD) of 5799 and 5469 and post mortem interval (PMI) of 288 and 248d, respectively. The spatial extent for dissolved organic carbon (DOC) and organic nitrogen (DON) for both bodies was large but similar suggesting some movement off site for both compounds. Mean DOC was 1087±727 and 1484±1236μgg(-1) dry soil under the two corpses relative to 150±68μgg(-1) in upslope control soils. Sulfate tended to have 'hot spots' of lower values relative to the control soils indicative of anaerobic respiration. pH was lower and electrical conductivity was higher in the soil under both decomposing cadavers relative to control soils. Some of the nutrients examined downslope of the human remains were significantly higher than control soils upslope suggesting movement of decomposition products off-site which could be an important factor when using human remains detector dogs.     

A method of retrospective determination of the onset of the development of insects on the corpse

Calculation method of retrospective determination of insect development onset in a cadaver is based on temperature parameters which regulate insect growth. Method contributes to reliable scientific estimation of postmortem interval on the basis of entomologic studies performed.     

Decomposing Human Blood: Canine Detection Odor Signature and Volatile Organic Compounds

The admissibility of human “odor mortis” discrimination in courts depends on the lack of comprehension of volatile organic compounds (VOCs) during the human decay process and of the lack in standardized procedures in training cadaver dogs. Blood was collected from four young people who died from traffic accidents and analyzed using HS‐SPME/GC‐MS at different decompositional stages. Two dogs, professionally trained, were tested to exactly locate blood samples, for each time point of the experiment. We found a long list of VOCs which varied from fresh to decomposed blood samples, showing differences in specific compounds. Dog performance showed a positive predictive value between 98.96% and 100% for DOG A, and between 99.47% and 100% for DOG B. Our findings demonstrated that decomposing human blood is a good source of VOCs and a good target for canine training.     

Identification of decomposition volatile organic compounds from surface-deposited and submerged porcine remains

Cadaver dogs are routinely used internationally by police and civilian search organisations to locate human remains on land and in water, yet little is currently known about the volatile organic compounds (VOCs) that are released by a cadaver underwater; how this compares to those given off by a cadaver deposited on land; and ultimately, how this affects the detection of drowned victims by dogs. The aim of this study was to identify the VOCs released by whole porcine (Sus scrofa domesticus) cadavers deposited on the surface and submerged in water using solid phase microextraction gas chromatography mass spectrometry (SPME GC–MS) to ascertain if there are notable differences in decomposition odour depending on the deposition location.For the first time in the UK, the volatile organic compounds (VOCs) from the headspace of decomposing porcine cadavers deposited in both terrestrial and water environments have been detected and identified using SPME-GCMS, including thirteen new VOCs not previously detected from porcine cadavers. Distinct differences were found between the VOCs emitted by porcine cadavers in terrestrial and water environments. In total, seventy-four VOCs were identified from a variety of different chemical classes; carboxylic acids, alcohols, aromatics, aldehydes, ketones, hydrocarbons, esters, ethers, nitrogen compounds and sulphur compounds. Only forty-one VOCs were detected in the headspace of the submerged pigs with seventy detected in the headspace of the surface-deposited pigs. These deposition-dependent differences have important implications for the training of cadaver dogs in the UK. If dog training does not account for these depositional differences, there is potential for human remains to be missed.Whilst the specific odours that elicit a trained response from cadaver dogs remain unknown, this research means that recommendations can be made for the training of cadaver dogs to incorporate different depositions, to account for odour differences and mitigate the possibility of missed human remains operationally.     

A diagnostic program for estimating the time of death using microcalculators MK-61 and B3-34

The programme design is based on the process of changes in dead body temperature. Specific features of the process of changes in temperature values of a dead body are characterized by a parameter which involves process sample obtained by temperature measurements in diagnostical area of a cadaver at the accident scene during 1 hour. Programme provides for estimation of postmortem interval within the first 60 h after death occurrence. Diagnostical deviations don't exceed +/- 3% as compared to the real time of death.     

An analytical evaluation of eight on-site oral fluid drug screening devices using laboratory confirmation results from oral fluid

A decaying cadaver emits volatile organic compounds that are used by necrophilous and necrophagous insects in order to find their brood substrate. Although volatile organic compounds (VOCs) that are released by carcasses have been identified, little is known about the specific compounds that are used by these insects while searching for a brood substrate. Therefore, we have investigated the chemical ecology involved in the attraction of the necrophagous hide beetle Dermestes maculatus, which feeds as an adult and larva upon decomposing carcasses. Our aims have been to identify the responsible compounds in the odours of the carcass that are important for the attraction of the beetles. Furthermore, we have studied sex- and age-related differences in beetle attraction and tested whether the hide beetle can distinguish between various stages of decomposition by means of the emitted odours. Headspace collection of volatiles released from piglet carcasses (bloated stage, post-bloating stage, advanced decay and dry remains), coupled gas chromatography-mass spectrometry (GC-MS), gas chromatography with electroantennographic detection (GC-EAD) and bioassays were conducted to identify the volatiles responsible for the attraction of the beetles. Freshly emerged male beetles were attracted by the odour of piglets in the post-bloating stage (9 days after death; T(mean) = 27 °C) and the EAD-active compound benzyl butyrate. Statistical analysis revealed a higher relative proportion of benzyl butyrate in the odour bouquet of the post-bloating stage in comparison with the other stages. We therefore conclude that this compound plays an important role in the attraction of hide beetles to carcass odour. This underlines the potential use of D. maculatus for the estimation of the post mortem interval. The decomposition stage at which the female beetles are attracted to the odour of a cadaver remains unknown, as does the nature of this attraction. Pheromones (sexual or aggregation pheromones) might play an essential role correlated with their attraction to carrion and consequently with their attraction to the substrate for mating and ovipositioning.     

Postmortem interval estimation by creatinine levels in human psoas muscle.

A new method was tested for estimating time after death in the middle range of postmortem interval (weeks). Creatinine muscular concentration in human cadaver is positively correlated to postmortem estimation. Temperature should be mainly related to the creatinine transformation rate. A stronger correlation was found at 11 degrees C up to 30 days and at 20 degrees Celsius up to 15 days.     

Application of forward‐looking infrared (FLIR) imaging from an unmanned aerial platform in the search for decomposing remains

Traditional methods of cadaver detection in outdoor environments include manual ground search, cadaver dogs, and manned aerial reconnaissance during daylight. These methods have limitations; however, a potential low‐cost alternative may be to employ thermal imaging equipment mounted on an unmanned aerial vehicle (UAV) to detect heat emitted by insect and bacterial activity on the decomposing remains. No studies have addressed the influence of wrappings on detection of maggot mass thermal signatures nor assessed thermal detection of smaller body fragments. We addressed these knowledge gaps by utilizing a two‐phase experimental approach to explore thermal detection of carcasses using UAV‐mounted infrared imaging. In Phase 1, pig body fragments were deposited on the surface or shallow buried. In Phase 2, whole pig carcasses were deposited in four conditions: on the surface uncovered, wrapped in plastic or carpet, or buried. Our results demonstrated that observable heat emissions from remains corresponded to peak insect activity during active decay and could be readily detected in uncovered whole carcasses and fragments. Although plastic and carpet wrappings partly impeded detection of insect heat signatures, these materials were clearly detectable themselves because of their contrast to the background ground surface. Thermal signatures of buried partial remains and disturbed gravesoil were also observed; however, the buried whole carcass transitioned to adipocere prior to the decay stage and without any insect colonization or heat signature. These data can inform operational implementation of this technique to complement existing search strategies to offer a robust, low‐cost alternative for use where scene characteristics allow.