Examination of adipocere formation in a cold water environment

An investigation of the inter and intra post-mortem microstructural change seen in an experimental series of pigs exposed to a marine environment

The identification of marine post-mortem microstructural change in human bone tissue is valuable in forensic casework as evidence of an individual's burial history. This study examined micro-tunneling in pig-bone tissue microstructure that had been submerged in a marine environment. The objective of the experiment was to assess total distribution of post-mortem microstructural change and degree of preservation within and between individual submerged pig skeletons. 14 juvenile pig carcasses were submerged in British Columbia at 92-300 m depths, between four to eight months. Seven pigs were individually submerged within caged platforms, seven were tied to open platforms. Six bones were selected from each carcass: first rib, radius, ulna, middle-rib, tibia, and femur. Two transverse thin sections were sampled at each bone mid-shaft (n = 148) and examined using circularly polarized transmitted light. The distribution of tunnels was assessed by measuring tunnel maximum ingress and diameter at 40 locations of the peripheral cortex. All element types were impacted by peripheral tunneling from the periosteum to the central cortex. Tunnels were observed as radiating, bifurcating with no remineralization boundary, isolated and in clusters. Tunnel diameters ranged between 2.00 μm and 12.8 μm, with a 3.7 μm mean. Ingress measurements ranged between 7.5 μm and 435.8 μm with a 93.0 μm mean. Distribution of post-mortem microstructural change across skeletal elements showed the averaged maximum ingress was deeper in the uncaged (99.6 μm), when compared to caged material (78.5 μm). The averaged tunnel ingress had statistically significant differences between uncaged and caged carcasses overall (p-value=0.02). Results of the study indicate microboring is present in marine submersed mammalian bone microstructure in as little as 134 days. This informs forensic investigators of the rate of skeletal destruction and of the narrow window for forensic recoveries, particularly in an enclosed environment. Furthermore, the presence of marine microboring in bone can assist forensic practitioners to histologically interpret the environmental history of a corpse.

Function, life histories, and biographies of Lower Paleolithic patinated flint tools from Late Acheulian Revadim, Israel

Flint tools exhibiting modified patinated surfaces ("double patina", or post-patination flaked items) provide a glimpse into Paleolithic lithic recycling, stone economy, and human choices. Different life cycles of such items are visually evident by the presence of fresh new modified surfaces alongside old patinated ones (according to color and texture differences). New modifications testify to a gap in time between the previous life cycle of the patinated flaked item and its new one. The aim of the current study is to reconstruct the functional properties and life cycles of a sample of modified patinated flaked tools from Late Acheulian Revadim, Israel by applying use-wear and residue analyses. The results of the functional study allow a better understanding of the practical reasoning behind the collection and recycling of old flint tools, while additional inputs from theoretical and methodological advancements assist in reconstructing their probable role in the worldviews of the site's inhabitants.

Outdoor human decomposition in Sweden: A retrospective quantitative study of forensic-taphonomic changes and postmortem interval in terrestrial and aquatic settings

This paper presents a quantitative retrospective study of gross human decomposition in central and southeastern Sweden. The applicability of methods developed abroad for postmortem interval (PMI) estimation from decomposition morphology and temperature are is evaluated. Ninety-four cases were analyzed (43 terrestrial and 51 aquatic) with a median PMI of 48 days. The results revealed differences in decomposition patterns between aquatic, surface, hanging, and buried remains. While partial saponification and desiccation occurred in cases of surface remains, complete skeletonization was observed in all cases with a PMI over two years. Aquatic skeletonization was slower due to extensive saponification in cases with PMI higher than one year. Formulae for assessing accumulated degree-days (ADD) from the original methods did not fit the study material. However, a regression analysis demonstrated that 80% of decomposition variance in surface remains could be explained by ADD, suggesting that a geographically adapted equation holds promise for assessing PMI. In contrast, the model fit was poor for aquatic cases (43%). While this may be explained by problems in obtaining reliant aquatic temperature data or an insufficient scoring system, aquatic decomposition may be highly dependent on factors other than ADD alone. This study evaluates the applicability of current PMI methods on an outdoor sample from a previously unpublished region, and represents the first scientific publication of human outdoor decomposition patterns in Sweden. Suggestions for future research are provided, including that scoring methods should incorporate saponification to fit forensic taphonomy in Swedish environments.

An integrated study discloses chopping tools use from Late Acheulean Revadim (Israel)

Chopping tools/choppers provide one of the earliest and most persistent examples of stone tools produced and used by early humans. These artifacts appeared for the first time ~2.5 million years ago in Africa and are characteristic of the Oldowan and Acheulean cultural complexes throughout the Old World. Chopping tools were manufactured and used by early humans for more than two million years regardless of differences in geography, climate, resource availability, or major transformations in human cultural and biological evolution. Despite their widespread distribution through time and space in Africa and Eurasia, little attention has been paid to the function of these items, while scholars still debate whether they are tools or cores. In this paper, we wish to draw attention to these prominent and ubiquitous early lithic artifacts through the investigation of 53 chopping tools retrieved from a specific context at Late Acheulean Revadim (Israel). We combined typo-technological and functional studies with a residue analysis aimed at shedding light on their functional role within the tool-kits of the inhabitants of the site. Here we show that most of the chopping tools were used to chop hard and medium materials, such as bone, most probably for marrow extraction. A few of the tools were also used for cutting and scraping activities, while some also served as cores for further flake detachment. The chopping tools exhibit extraordinarily well-preserved bone residues suggesting they were used mainly for bone-breaking and marrow acquisition. We discuss the data and explore the tool versus core debate also in light of a sample of 50 flake cores made on pebbles/cobbles retrieved from the same archeological layer. The results add further pieces to the puzzle of activities carried out at Revadim and add to our knowledge of the production and use of these enigmatic tools and their role in human evolutionary history.

A practical review of adipocere: Key findings, case studies and operational considerations from crime scene to autopsy

After death, the body begins decomposition, a process that starts with the breakdown of organic matter and typically leads to the complete degradation of a body. Such a process is highly affected by (micro and macro) environmental factors of intrinsic and extrinsic nature. Adipocere is a substance formed from the decomposition of adipose tissue and represents a disruption to the typical decomposition process. Such disruption causes decomposition to slow or arrest completely, placing a body into a state of preservation, and determines complications in the estimation of the time since death (Post-Mortem Interval, PMI). While several studies have been performed on the nature, the formation and the degradation of adipocere, there is still no reliable model to assess the PMI of a body exhibiting it. Case studies are an important source to aid pathologists and investigators during a case. This review presents a summary and an update on the knowledge surrounding the chemistry and the factors affecting adipocere formation and degradation, the timing and the distribution of adipocere throughout a body, and the techniques used to investigate it. Furthermore, a table of the most important case studies involving adipocere since 1950, several images and descriptions of recent cases and operational considerations for the best practice at the crime scene and autopsy are presented to be used as a reference to facilitate forensic professionals in adipocere cases.

Understanding clothed buried remains: the analysis of decomposition fluids and their influence on clothing in model burial environments

Previous studies of fabric degradation have shown promising results for post-mortem interval estimations based on differences in the degradation states of clothing in the presence of decomposing remains. It is crucial to determine if a body was present when using the degradation state as an indicator of time since death. For this study, fabric samples from buried pig remains were collected and analyzed using attenuated total reflectance Fourier transform infrared spectroscopy and chromatography- mass spectrometry. Three different fabrics were investigated; 100% cotton, 100% polyester and a polyester-cotton blend. Distinct visual changes were observed between the experimental and control graves, with the fabrics in the control grave degrading more rapidly. There was also a difference between the fabric types, whereby the natural fabrics degraded much faster than the synthetic ones. Principal component analysis was used to determine that the cotton control samples could be statistically separated based on their degradation state. The presence of lipids and proteins were useful for separating "wetter" graves from those drier in nature as well as the control graves. Clothing evidence was demonstrated to provide quantitative time since death information, as well as indicating the decomposition site in the event of intentional or unintentional movement.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300cm(-1) increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A1172/A1126, A1456/A1403, and A2925/A2957 were significantly increased, whereas the A1652/A1541 ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737cm(-1) were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.