Characteristics and Frequency of Chipping Effects in Near‐Contact Gunshot Wounds

The presence of “chipping” or “flaking” around the edges of gunshot entry wounds has been described among the characteristics of gunshot wounds in bone. In this study, the real frequency of such a peculiar feature was investigated. The presence of “chipping” was assessed on 22 gunshot wounds fired at a near‐contact range on bovine ribs with 9‐mm bullets. As controls, five samples were shot with a 3 cm range, and five from 40 cm. In 77% of cases shot at near‐contact range, a detachment of small fragments of the upper layers of bone was detected, mainly with a circumferential disposition, whereas this feature was lacking in control samples. The study demonstrated the frequency of “chipping” and that it may probably be due to a combined ballistic effect of impact of the bullet itself and expansion of gases. It may be thus considered indicative of close‐range shots.     

Sex Assessment from the Volume of the First Metatarsal Bone: A Comparison of Linear and Volume Measurements

Sexual dimorphism is a crucial characteristic of skeleton. In the last years, volumetric and surface 3D acquisition systems have enabled anthropologists to assess surfaces and volumes, whose potential still needs to be verified. This article aimed at assessing volume and linear parameters of the first metatarsal bone through 3D acquisition by laser scanning. Sixty‐eight skeletons underwent 3D scan through laser scanner: Seven linear measurements and volume from each bone were assessed. A cutoff value of 13,370 mm³ was found, with an accuracy of 80.8%. Linear measurements outperformed volume: metatarsal length and mediolateral width of base showed higher cross‐validated accuracies (respectively, 82.1% and 79.1%, raising at 83.6% when both of them were included). Further studies are needed to verify the real advantage for sex assessment provided by volume measurements.     

The Micro‐Taphonomy of Cold: Differential Microcracking in Response to Experimental Cold‐Stresses

Cold is a central feature of environments at higher latitudes and elevations. Thus, cold‐induced taphonomic changes are relevant in many forensic contexts. Fifty‐two lamb bone segments were used to assess the impact of cold, freeze‐thaw cycles, freeze‐drying, and water immersion on microstructural cracking of bone in a series of controlled exposure experiments. For each bone segment, three thin sections were examined under a light microscope. Cold exposure caused taphonomic changes in the form of microscopic cracking. Transverse cracks occurred in all treatments, whereas osteonal cracks were restricted to rapid freezing treatments. Type of cold exposure had a statistically significant effect on both the total number of cracks and each type of crack observed. Skeletal microcracking could potentially be used as a taphonomic indicator of postmortem bone exposure to sub‐zero temperatures. The type and prevalence of this damage could also be used to distinguish between different types of cold exposure.     

A Simple and Efficient Method of Extracting DNA from Aged Bones and Teeth

DNA is often difficult to extract from old bones and teeth due to low levels of DNA and high levels of degradation. This study established a simple yet efficient method for extracting DNA from 20 aged bones and teeth (approximately 60 years old). Based on the concentration and STR typing results, the new method of DNA extraction (OM) developed in this study was compared with the PrepFiler? BTA Forensic DNA Extraction Kit (BM). The total amount of DNA extracted using the OM method was not significantly different from that extracted using the commercial kit (p > 0.05). However, the number of STR loci detected was significantly higher in the samples processed using the OM method than using the BM method (p < 0.05). This study aimed to establish a DNA extraction method for aged bones and teeth to improve the detection rate of STR typing and reduce costs compared to the BM technique.     

An Analysis of Systematic Elemental Changes in Decomposing Bone

The aim of this pilot study was to investigate compositional changes in bone during decomposition. Elemental concentrations of barium, calcium, iron, potassium, magnesium, zinc and phosphorus in porcine bone (as an experimental analog for human bone) were analyzed by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The samples were taken from porcine bone subjected to shallow burial and surface depositions at 28‐day intervals for a period of 140 days. Results indicated that ICP‐OES elemental profiling has potential to be developed as a forensic test for determining whether a bone sample originates from the early stages of soft tissue putrefaction. Significant changes in iron, sodium and potassium concentrations were found over 140 days. These elements are known to be primarily associated with proteins and/or tissue fluids within the bone. Changes in their respective concentrations may therefore be linked to dehydration over time and in turn may be indicative of time since deposition.     

手腕部桡、尺骨骺线消失作为推测18岁年龄的指征

目的探讨手腕部桡、尺骨骺线消失是否可以作为推测青少年18岁年龄的指征。方法研究样本为15～20岁的中国5城市4492名（男1942,女2550）汉族健康青少年。在受试者出生日前后15d内拍摄左手腕正位X线片。根据骺线是否可辨评价桡、尺骨远侧骺的发育,计算年龄组骺线不可辨的例数及其构成比。结果在18岁以下,男、女青少年桡骨骺线不可辨等级出现的构成比分别为0.9%和4.9%,尺骨骺线不可辨等级出现的构成比分别为13.1%和69.2%。结论手腕部桡骨骺线消失可作为推测青少年18岁年龄的指征。     

应用Young-Burgess分型推断交通事故受伤人员骨盆损伤机制

目的根据骨盆骨折X线片Young-Burgess分型推断道路交通事故致死者（roadtrafficfatalities,RTFs）骨盆损伤机制,并探讨其法医学应用价值。方法回顾性分析128例车外成人RTFs尸体骨盆X线片的Young-Burgess分型,根据分型推断骨盆损伤机制,对照真实案情进行统计分析。结果可区分APC、LC亚型的推断骨盆损伤机制正确率（94.1%、92.9%）明显高于不区分亚型的（63.6%、70.7%）（P〈0.05）;区分LC亚型还能进一步推断后侧方、前侧方或是持续、较大的前侧方外力。结论综合各种影像手段区分Young-Burgess亚型可较好地推断骨盆损伤机制,为道路交通事故现场重建提供可靠依据。     

Determining Volumetric Shrinkage Trends of Burnt Bone Using Micro-CT

Understanding the degree and pattern of shrinkage undergone by bone when subjected to heating is crucial to accurately deduce a biological profile from incinerated remains. X-ray microtomography (micro-CT) enables a nondestructive insight into hard tissue structural changes, while allowing for an accurate documentation of volumetric and trabecular shrinkage. Sheep ribs were experimentally burned at temperatures between 400 and 1000°C in 100°C increments and their volumetric shrinkage was calculated. Observed shrinkage ranged from 14.0% at 400°C to 45.5% at 1000°C. Bones burned at temperatures up to 600°C showed no significant difference, whereas the 700 and 800°C samples exhibited higher shrinkage. Bones burnt at 900 and 1000°C showed significantly higher shrinkage than the other temperature groups. Findings signify the potential of micro-CT in research on the effects of factors such as diagenesis or burning on the bone density, morphology and microarchitecture.     

A Method to Interpolate Osteon Volume Designed for Histological Age Estimation Research

Aging adult skeletal material is a crucial component of building the biological profile of unknown skeletal remains, but many macro- and microscopic methods have challenges regarding accuracy, precision, and replicability. This study developed a volumetric method to visualize and quantify histological remodeling events in three dimensions, using a two-dimensional serialized approach that applied circular polarizing microscopy and geographic information systems protocols. This approach was designed as a tool to extend current histological aging methodologies. Three serial transverse sections were obtained from a human femoral midshaft. A total sample size of 6847 complete osteons from the three sections was identified; 1229 osteons connected between all sections. The volume of all connected osteons was interpolated using ArcGIS area calculations and truncated cone geometric functions. Each section was divided into octants, and two random samples of 100 and of 30 connected osteons from each octant were generated. Osteon volume was compared between the octants for each random sample using ANOVA. Results indicated that the medial aspect had relative uniformity in osteon volume, whereas the lateral aspect showed high variability. The anterolateral–lateral octant had significantly smaller osteon volume, whereas the posterior–posterolateral octant had significantly larger osteon volume. Results also indicated that a minimum of 100 osteons is statistically more robust and more representative of normal osteon distribution and volume; the use of 30 osteons is insufficient. This research has demonstrated that osteon volume can be interpolated using spatial geometry and GIS applications and may be a tool to incorporate into adult age-at-death estimation techniques.     

基于数据挖掘实现成人喉软骨和舌骨CT图像重组的年龄推断

目的 运用数据挖掘技术探索喉软骨和舌骨CT图像重组用于成人年龄推断的可行性.方法 收集413例颈部薄层CT图像,样本年龄范围18～<80岁,将样本随机分为测试集和训练集.参照TURK等的分级方法,对所有样本进行全方位综合阅片分级,将甲状软骨骨化过程分为6级,环状软骨骨化过程分为5级,舌骨大角和舌骨体的骨性结合分为3级....