An Aquatic Decomposition Scoring Method to Potentially Predict the Postmortem Submersion Interval of Bodies Recovered from the North Sea

This study aimed to develop an aquatic decomposition scoring (ADS) method and investigated the predictive value of this method in estimating the postmortem submersion interval (PMSI) of bodies recovered from the North Sea. This method, consisting of an ADS item list and a pictorial reference atlas, showed a high interobserver agreement (Krippendorff's alpha ≥ 0.93) and hence proved to be valid. This scoring method was applied to data, collected from closed cases—cases in which the postmortal submersion interval (PMSI) was known—concerning bodies recovered from the North Sea from 1990 to 2013. Thirty‐eight cases met the inclusion criteria and were scored by quantifying the observed total aquatic decomposition score (TADS). Statistical analysis demonstrated that TADS accurately predicts the PMSI (p < 0.001), confirming that the decomposition process in the North Sea is strongly correlated to time.     

Application of Enhanced Point Estimators to a Sample of In Vivo CT‐derived Facial Soft Tissue Thicknesses

Facial approximations based on facial soft tissue depth measurement tables often utilize the arithmetic mean as a central tendency estimator. Stephan et al. (J Forensic Sci 2013;58:1439) suggest that the shorth and 75‐shormax statistics are better suited to describe the central tendency of non‐normal soft tissue depth data, while also accommodating normal distributions. The shorth, 75‐shormax, arithmetic mean, and other central tendency estimators were evaluated using a CT ‐derived facial soft tissue depth dataset. Differences between arithmetic mean and shorth mean for the tissue depths examined ranged from 0 mm to +2.3 mm (average 0.6 mm). Differences between the arithmetic mean plus one standard deviation (to approximate the same data points covered by the 75‐shormax) and 75‐shormax values ranged from ?0.8 mm to +0.7 mm (average 0.2 mm). The results of this research suggest that few practical differences exist across the central tendency point estimators for the evaluated soft tissue depth dataset.     

Application of MALDI‐TOF MS for Estimating the Postmortem Interval in Rat Muscle Samples

Estimating the postmortem interval (PMI) is very important in the forensic sciences. Although many approaches have been used for estimating the PMI, accurate PMI calculations are still difficult. In this study, four Sprague Dawley (SD) rats were sacrificed by suffocation, and muscle samples were collected by dissection at various time intervals (0, 48, 96, and 144 h) after death. All samples were probed using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to obtain molecular images and data for principal component analysis (PCA). The results showed that the peaks at m/z 1511, 1543, 1564, 1586 clearly decreased in intensity from 0 to 144 h postmortem and that the time groups were separated from each other on the PCA score plot. The prediction model showed high recognition capability (95.93%) and cross‐validation (83.72%). Our work suggests that MALDI‐TOF MS can be used to determine the PMI.     

A Computational Framework for Age‐at‐Death Estimation from the Skeleton: Surface and Outline Analysis of 3D Laser Scans of the Adult Pubic Symphysis

In forensic anthropology, age‐at‐death estimation typically requires the macroscopic assessment of the skeletal indicator and its association with a phase or score. High subjectivity and error are the recognized disadvantages of this approach, creating a need for alternative tools that enable the objective and mathematically robust assessment of true chronological age. We describe, here, three fully computational, quantitative shape analysis methods and a combinatory approach that make use of three‐dimensional laser scans of the pubic symphysis. We report a novel age‐related shape measure, focusing on the changes observed in the ventral margin curvature, and refine two former methods, whose measures capture the flatness of the symphyseal surface. We show how we can decrease age‐estimation error and improve prior results by combining these outline and surface measures in two multivariate regression models. The presented models produce objective age‐estimates that are comparable to current practices with root‐mean‐square‐errors between 13.7 and 16.5 years.     

The Reliability of Facial Recognition of Deceased Persons on Photographs

In humanitarian emergencies, such as the current deceased migrants in the Mediterranean, antemortem documentation needed for identification may be limited. The use of visual identification has been previously reported in cases of mass disasters such as Thai tsunami. This pilot study explores the ability of observers to match unfamiliar faces of living and dead persons and whether facial morphology can be used for identification. A questionnaire was given to 41 students and five professionals in the field of forensic identification with the task to choose whether a facial photograph corresponds to one of the five photographs in a lineup and to identify the most useful features used for recognition. Although the overall recognition score did not significantly differ between professionals and students, the median scores of 78.1% and 80.0%, respectively, were too low to consider this method as a reliable identification method and thus needs to be supported by other means.     

上颌中切牙牙根直径及根管管径与年龄的关系

目的探讨汉族人上颌中切牙牙根直径及根管管径与年龄的关系。方法 2014年11月~2015年11月间,在一家三甲医院数据库中选择420例汉族人的口腔锥形束CT资料,根据年龄将所有研究对象分为6个组别(8~12岁、13~17岁、18~22岁、23~27岁、28~32岁、33~37岁,每组70例,男女各15例。对所有研究对象上颌中切牙牙根直径及根管管径进行测量,取釉牙骨质界距根尖3/4处,分析上颌中切牙牙根直径及根管管径与年龄的关系,比较男女上颌中切牙牙根直径。结果男性与女性上颌中切牙牙根直径比较具有差异显著性(P0.05);男性与女性上颌中切牙牙根管径比较具有差异显著性(P0.05);男性与女性上颌中切牙牙根直径与牙根管径之比比较具有差异显著性(P0.05);不同性别间上颌中切牙牙根直径与牙根管径之比与年龄具有一定的相关性(R~2=0.623,P0.05)。结论汉族人上颌中切牙牙根直径及根管管径与年龄的变化具有相关性,且男性根管管径减小趋势比女性更高。     

应用膝关节MRI T_2加权脂肪抑制像推断活体年龄

目的探索膝关节MRI T2加权脂肪抑制像(T2-FS)在法医年龄推断中的应用价值,建立安全可靠的四川汉族年龄推断方法。方法收集膝关节MRI 324例(男性170例,女性154例),年龄范围为10~30岁。采用西门子1.5T磁共振仪摄片,MRI参数:T2-FS TSE序列,矢状位。将股骨远端、胫骨近端骨骺发育分为6个等级并赋分,分析各指标性别差异及年龄相关性,建立年龄推断回归模型。结果男女性股骨远端、胫骨近端MRI等级与年龄呈正相关性,股骨远端与年龄的相关性男性0.687,女性0.661;胫骨近端与年龄的相关性男性0.684,女性0.488。股骨远端骨骺完全闭合,骺线消失的最小年龄男性18.42岁,女性19.36岁;胫骨近端男性骺线消失的最小年龄为16.93岁,女性为14.68岁。股骨远端等级1~3、5、6和胫骨近端等级1~3、5年龄分布性别差异不显著。分别建立男女年龄推断模型,男性年龄推断平均绝对误差(MAD)=2.90岁;女性年龄推断MAD=3.30岁。结论膝关节MRI T2-FS影像可作为活体年龄推断的指标之一,股骨远端等级6可作为判断18岁的指标之一。     

阿维菌素在急性中毒死家兔体内的再分布研究

目的考察阿维菌素在急性中毒死家兔体内的再分布。方法按最小致死量一次性灌胃250mg/kg阿维菌素,HPLC法检测家兔死后0h、24h、48h和72h中阿维菌素的含量。结果给家兔一次性灌胃250mg/kg阿维菌素的临床死亡时间为120.6±9.2min(±s,n=10);测定了阿维菌素的致死血浓度和致死组织浓度;家兔死后0h~72h心血和各主要脏器组织中阿维菌素含量存在体内再分布现象;确定肝、肾、肺为最佳组织检材。结论阿维菌素在急性中毒死家兔体内的再分布数据,对法医办理此类案件具有重要参考价值。     

Algor mortis: an erroneous measurement following postmortem refrigeration

Determination of the time of death is one goal of medicolegal death investigations. Algor mortis has been used as a measure of the postmortem interval (PMI). We prospectively recorded the core temperatures of 19 adult bodies entering our morgue cooler and at 3, 6, and 9 h of refrigeration. We then compared the cooling rate with the calculated body mass index (BMI). For each individual body, the rate of cooling was fairly linear with no evidence of a plateau. There was fair to moderate correlation between the BMI and the cooling rate: cooling rate = -0.052 (BMI) + 3.52. The probability of linearity in any given case was 36%. Variables affecting this correlation included the presence and the layers of clothing and if the clothing was wet. Our data confirm that algor mortis is of very limited utility in determining the PMI in bodies that have been refrigerated.     

Age estimation and the developing third molar tooth: an analysis of an Australian population using computed tomography

The third molar tooth is one of the few anatomical sites available for age estimation of unknown age individuals in the late adolescent years. Computed tomography (CT) images were assessed in an Australian population aged from 15 to 25 years for development trends, particularly concerning age estimation at the child/adult transition point of 18 years. The CT images were also compared to conventional radiographs to assess the developmental scoring agreement between the two and it was found that agreement of Demirjian scores between the two imaging modalities was excellent. The relatively wide age ranges (mean ± 2SD) indicate that the third molar is not a precise tool for age estimation (age ranges of 3-8 years) but is, however, a useful tool for discriminating the adult/child transition age of 18 years. In the current study 100% of females and 96% of males with completed roots were over 18 years of age.