青少年肩关节X线片的骨龄研究

目的探讨青少年肩关节X线影像与年龄间的关系。方法对太原地区267名年龄在12～22岁的青少年拍摄肩关节X线片,根据X线片上的不同年龄特征,筛选出5个与年龄变化密切相关的影像标志点,进行分级评分,提出了肩关节X线片判定年龄的观察指标及分级标准,并使用SPSS包进行数据处理,建立了利用肩关节X线片判定青少年年龄的判别方程。结果判别方程y=9.517+0.518x1+0.913x2+0.465x3+0.436x4经方差分析,F>0.01,回归高度显著。将全部样本进行计算机方程回代检验,符合率为±1S72.01%,±2S96.3%,其结果达到了设计与统计学要求。方程具有实用价值。结论本项研究证实了青少年肩关节X线影像与年龄之间存在相关关系,并为司法鉴定时根据肩关节X线片判断年龄提供依据,同时也为人类学研究积累了资料。     

Performance of the supervised learning algorithms in sex estimation of the proximal femur: A comparative study in contemporary Egyptian and Turkish samples

Sex estimation standards are population specific however, we argue that machine learning techniques (ML) may enhance the biological sex determination on trans-population application. Linear discriminant analysis (LDA) versus nine ML including quadratic discriminant analysis (QDA), support vector machine (SVM), Decision Tree (DT), Gaussian process (GPC), Naïve Bayesian (NBC), K-Nearest Neighbor (KNN), Random Forest (RFM) and Adaptive boosting (Adaboost) were compared. The experiments involve two contemporary populations: Turkish (n = 300) and Egyptian populations (n = 100) for training and validation, respectively. Base models were calibrated using isotonic and sigmoid calibration schemes. Results were analyzed at posterior probabilities (pp) thresholds >0.95 and >0.80. At pp = 0.5, ML algorithms yielded comparable accuracies in the training (90% to 97%) and test sets (81% to 88%) which are not modified after employing the calibration techniques. At pp >0.95, the raw RFM, LDA, QDA, and SVM models have shown the best performance however, calibration techniques improved the performance of various classifier especially NBC and Adaboost. By contrast, the performance of GPC, KNN, QDA models worsened by calibration. RFM has shown the best performance among all models at both thresholds whereas LDA benefited the best from using both calibration methods at pp >0.80. Complex ML models are not necessarily achieving better performance metrics. LDA and QDA remain the fastest and simplest classifiers. We demonstrated the capability of enhancing sex estimation using ML on an independent population sample however, differences in the underlying probability distribution generated by models were detected which warranted more cautious application by forensic practitioners.     

Sex Determination by Discriminant Function Analysis of Lumbar Vertebrae

Sex determination is critical for developing the biological profile of unidentified skeletal remains. When more commonly used elements (os coxa, cranium) for sexing are not available, methods utilizing other skeletal elements are needed. This study aims to assess the degree of sexual dimorphism of the lumbar vertebrae and develop discriminant functions for sex determination from them, using a sample of South African blacks from the Raymond A. Dart Collection (47 males, 51 females). Eleven variables at each lumbar level were subjected to univariate and multivariate discriminant function analyses. Univariate equations produced classification rates ranging from 57.7% to 83.5%, with the highest accuracies associated with dimensions of the vertebral body. Multivariate stepwise analysis generated classification rates ranging from 75.9% to 88.7%. These results are comparable to other methods for sexing the skeleton and indicate that measures of the lumbar vertebrae can be used as an effective tool for sex determination.     

Identification of Missing Norwegian World War II Soldiers,in Karelia Russia

This article presents the multidisciplinary effort in trying to identify the skeletal remains of 100 Norwegian soldiers serving in the German army, killed in Karelia Russia in 1944, from the recovery of the remains through the final identification using DNA. Of the 150 bone samples sent for DNA testing, 93 DNA profiles were obtained relating to 57 unique individuals. The relatives could not be directly contacted as the soldiers were considered as traitors to Norway; therefore, only 45 reference samples, relating to 42 cases of the missing, were donated. DNA matches for 14 soldiers and 12 additional body part re‐associations for these individuals were found. Another 24 bone samples were re‐associated with 16 individuals, but no familial match was found. More than six decades after the end of WWII, DNA analysis can significantly contribute to the identification of the remains.     

两种骨龄标准推断女性14岁年龄的准确度

目的研究李果珍百分计数法和中国人手腕骨发育标准CHN法在推断女性14岁年龄时的准确度。方法在湖南娄底三所中学随机选择51名14岁女生,同一条件下拍摄左手腕X线片;按照上述两种方法由专业人员阅片;对比两种方法所得结果及其与真实年龄间的差异。结果计数法和CHN法测得的骨龄与研究对象的实际年龄间无显著性差异(P>0.05),两种方法比较也未见明显差异(P>0.05)。结论计数法和CNH法可用于湖南地区女性14岁年龄的推断。     

Metric assessment of the "mastoid triangle" for sex determination: a validation study

Recently, a metric approach to skeletal sex determination was published by Paiva and Segre which is based on the summation of two triangular areas defined by three distinct craniometric landmarks: Porion, Mastoidale, and Asterion. According to the authors, values for the total triangle > or =1447.40 mm(2) are characteristic for male crania, while values < or =1260.36 mm(2) are indicative of female skulls (95% confidence). In order to evaluate the method's validity, two sex- and age-documented samples of different provenience were analyzed (N=197). The results show that while the indicated measurements display significant sex differences, the technique is of little practical meaning where a single individual must be independently classified. It is hypothesized that differences in the expression of sexual dimorphism as well as a population-specific variability of the asterion location undermine the value of the mastoid triangle as a sex determinant.     

Humeral and femoral head diameters in recent white American skeletons

Osteologists often rely on single measurements, such as humeral and femoral head diameters, to estimate sex, especially when skeletons are incomplete. Measurements of 237 Bass Donated Collection skeletons provide a means of distinguishing white American females from males based on a modern sample: humeral head, female mean 42.1 mm, male mean 49.0 mm; and femoral head, female mean 42.2 mm, male mean 48.4 mm. Probabilities that bones at 1-mm increments came from females (p(f)) are estimated (p(m) = 1 - p(f)). An overrepresentation of one sex in the skeletons that are examined influences the probability that a bone of a certain size is from a female or male. So, probabilities are also estimated for samples consisting of an unequal number of males and females. Sample composition has its greatest effect when one sex dominates the remains that are the subject of investigation.     

Comparison of two methods for isolating DNA from human skeletal remains for STR analysis

Abstract: The quality and efficiency of a standard organic DNA isolation method and a silica‐based method using the QIAGEN Blood Maxi Kit were compared to obtain human DNA and short tandem repeats (STRs) profiles from 39 exhumed bone samples for paternity testing. DNA samples were quantified by real‐time PCR, and STR profiles were obtained using the AmpFlSTR^® Identifiler^® PCR amplification kit. Overall, the silica‐based method recovered less DNA ranging from 0 to 147.7 ng/g (average 7.57 ng/g, median = 1.3 ng/g) than did the organic method ranging from 0 to 605 ng/g (average 44.27 ng/g, median = 5.8 ng/g). Complete profiles (16/16 loci tested) were obtained from 37/39 samples (95%) using the organic method and from 9/39 samples (23%) with the silica‐based method. Compared with a standard organic DNA isolation method, our results indicate that the published silica‐based method does not improve neither the quality nor the quantity of DNA for STR profiling.     

Pubic Symphyseal Age Estimation from Three‐Dimensional Reconstructions of Pelvic CT Scans of Live Individuals

Skeletal age estimation using the pubic symphysis is a reliable and popular practice among forensic anthropologists. In instances in which accessing the skeleton is impossible, such as in the case of living individuals, three‐dimensional (3D) reconstructions of computed tomography (CT) scans can be created and analyzed for aspects of the biological profile. This study examined 3D reconstructions of pelvic CT scans of a sample of 44 live adults to estimate age using the Suchey–Brooks J Hum Evol 1990;5(3):227‐38 method. Images were created using OsiriX software (Pixmeo, Geneva, Switzerland). Estimated age ranges based on the 3D‐CT images captured the true age of the individual at the time of the CT scan 79.5% of the time with good intra‐observer reliability. The features best visualized on the 3D images included the ossific nodule and the pubic symphyseal rim. This study shows that clinical CT scanning parameters are adequate for creating 3D images to be analyzed for age using the pubic symphysis.     

Examination of Hacking and Blunt Force Skeletal Trauma

Hacking trauma is prevalent in forensic cases involving genocide and dismemberment, but research into the identification of this type of trauma is lacking. The present study examines characteristics of hacking and blunt force skeletal trauma in order to determine if there is a point at which blunt force trauma becomes distinguishable from hacking trauma. Ten implements with a range of blade angles (i.e., the striking surface of the implement) were used in conjunction with a controlled-force hacking device to impact 100 limb bones of white-tailed deer (Odocoileus virginianus). Observations of the trauma included the occurrence and degree of fragmentation, the entrance widths of the impacts, and composite scores of six hacking characteristics, especially the distinctive V-shaped kerf. ANOVA tests and regression analyses were used to assess the relationships between these characteristics and the blade angles. A significant relationship (p-value = 0.011) was found between the composite hacking scores and the blade angles, indicating that blunt force and hacking trauma can be distinguished. The entrance widths of the impacts exhibited a significant relationship with the blade angles (p-value = 0.037). There was also a significant relationship between the visibility of a V-shaped kerf in the bones (p-value = 0.003), with visibility decreasing around the 60° blade angle. These data should assist in establishing guidelines to differentiate hacking and blunt force skeletal trauma in cases where the implement is on a spectrum between sharp and blunt.