A new type of shotgun ammunition produces unique wound characteristics

The Tucson Police Department, Tucson, AZ, has begun using the Polyshok Impact Reactive Projectile (IRP), a new type of shotgun ammunition that includes a lead bead core that travels within single, plastic-encased projectile. On impact, the core is released to distribute over a small area, thereby disintegrating on impact to reduce the likelihood of exit or collateral damage on missed shots. After a brief review of shotgun slug ballistics and wound characteristics and a discussion of the mechanism of the Polyshok IRP, we report the first death in the United States from this ammunition. Findings included a single entrance wound with plastic ammunition components and small lead particles recovered from the body, the combination of which normally would suggest a close-range shooting with birdshot. However, the characteristics of this ammunition create different patterns than are found with slugs or shot, so that a medical examiner unfamiliar with the Polyshok IRP could draw inaccurate conclusions about ammunition and range of fire. Because the single projectile fired from this ammunition is composed of both plastic and lead, plastic components are likely to be found within the wound at any range of fire, unlike traditional shot or slug ammunition. Also, the small size of lead particles found spread through the wound cavity would ordinarily suggest a small-size shot, whereas the external appearance of the wound (a single entrance with no dispersion of shot) and the pattern of tissue destruction are more consistent with the patterns of injury associated with shotgun slugs.     

Mandibular morphology as an indicator of human subadult age: interlandmark approaches

The dentition is widely recognized as the set of developmental markers that appear to show the least variability against chronological age; these markers are thus widely used in forensic anthropological investigations. As a possible alternative, we investigate here the potential of mandibular morphology as a developmental marker for estimating age at death in subadults. The sample analyzed comprises 79 known age and sex subadult individuals of South African Bantu and African American origin. Linear measurements of ramus height were obtained from the mathematical conversion of three-dimensional landmark data. A series of regression analyses were then performed to predict age by using the measurement of ramus height; results were cross-validated using a jackknife procedure. Our results show that ramus height can be used to predict age in the subadult skeleton with accuracy, closely approaching that of standards based on the dentition (standard error rates are between +/-1.1 years and +/-2.4 years).     

Application of 3D documentation and geometric reconstruction methods in traffic accident analysis: with high resolution surface scanning, radiological MSCT/MRI scanning and real data based animation

The examination of traffic accidents is daily routine in forensic medicine. An important question in the analysis of the victims of traffic accidents, for example in collisions between motor vehicles and pedestrians or cyclists, is the situation of the impact. Apart from forensic medical examinations (external examination and autopsy), three-dimensional technologies and methods are gaining importance in forensic investigations. Besides the post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) for the documentation and analysis of internal findings, highly precise 3D surface scanning is employed for the documentation of the external body findings and of injury-inflicting instruments. The correlation of injuries of the body to the injury-inflicting object and the accident mechanism are of great importance. The applied methods include documentation of the external and internal body and the involved vehicles and inflicting tools as well as the analysis of the acquired data. The body surface and the accident vehicles with their damages were digitized by 3D surface scanning. For the internal findings of the body, post-mortem MSCT and MRI were used. The analysis included the processing of the obtained data to 3D models, determination of the driving direction of the vehicle, correlation of injuries to the vehicle damages, geometric determination of the impact situation and evaluation of further findings of the accident. In the following article, the benefits of the 3D documentation and computer-assisted, drawn-to-scale 3D comparisons of the relevant injuries with the damages to the vehicle in the analysis of the course of accidents, especially with regard to the impact situation, are shown on two examined cases.     

不同年龄下颌骨应力分布与骨折发病率的关系

目的分析不同年龄的下颌骨正中受力时,下颌骨三维有限元分布的差异。方法选用儿童、中年和老年的下颌骨,采用螺旋CT扫描,MIMICS软件建模,HYPERMESH软件划分单元,ANSYS进行三维有限元应力分布分析。结果三种年龄下颌骨最大的平均综合应力均出现在下颌角;中年的下颌颈有应力的分布,但老年和儿童的下颌颈几乎没有应力的分布。结论下颌骨应力的分布与骨折的发病率相关,不同年龄下颌骨应力的分布与骨折的高发年龄相关。     

TW2、TW3法腕骨骨龄评价方法的诊断性试验

目的比较TW2法英国人标准、TW2法中国人南方标准和TW3法测定腕骨骨龄对特发性性早熟(IPP)女孩的诊断价值。方法女性IPP患儿55例;对照组83例。回顾性分析初诊左腕X线片,用TW2法、TW2CHC中国人南方标准和TW3法盲法分期,分别测得其腕骨骨龄及其百分位,并分为5个连续性的工作点,即:>P97、>P90、>P75、>P50和、≤P50。结果敏感度(Sen)和特异度(Spe)都比较高的有以下3个工作点:TW2CH“>P90”点,TW3“>P90”点,TW2“>P90”点。结论TW系统3种腕骨骨龄对于IPP女孩都有诊断价值,TW3法和TW2法中国人南方标准诊断价值比较高,TW2法英国人标准的诊断价值为中等。     

大鼠皮肤切创愈合过程中泛素的表达及其法医学意义

目的观察大鼠皮肤切创后泛素(ubiquitin)表达的变化规律。方法应用免疫组化方法,观察大鼠皮肤切创后1、3、6、12h和1、3、6、10、14d ubiquitin的表达情况,并用图像分析系统进行图像分析。结果正常对照组大鼠皮肤有低水平ubiquitin表达,切创后ubiquitin表达增加,伤后6d达峰值,伤后10d开始下降,伤后14d恢复到正常水平。结论ubiquitin可作为法医学损伤时间推断的有效指标。     

A Review of Bomb Pulse Dating and its Use in the Investigation of Unidentified Human Remains

In cases where there is limited antemortem information, the examination of unidentified human remains as part of the investigation of long-term missing person's cases is a complex endeavor and consequently requires a multidisciplinary approach. Bomb pulse dating, which involves the analysis and interpretation of 14C concentration, is one technique that may assist in these investigations by providing an estimate of year of birth and year of death. This review examines the technique of bomb pulse dating and its use in the identification of differentially preserved unknown human remains. Research and case studies implementing bomb pulse dating have predominantly been undertaken in the Northern Hemisphere and have demonstrated reliable and accurate results. Limitations were, however, identified throughout the literature. These included the small sample sizes used in previous research/case studies which impacted on the statistical significance of the findings, as well as technique-specific issues. Such limitations highlight the need for future research.     

A Test of the Passalacqua Age at Death Estimation Method Using the Sacrum

A test of the accuracy of the Passalacqua (J Forensic Sci, 5, 2009, 255) sacrum method in a forensic context was performed on a sample of 153 individuals from the J.C.B. Grant Skeletal Collection. The Passalacqua (J Forensic Sci, 5, 2009, 255) method assesses seven traits of the sacrum using a 7‐digit coding system. An accuracy of 97.3% was achieved using the Passalacqua (J Forensic Sci, 5, 2009, 255) method to estimate adult skeletal age. On average each age estimate differed by 12.87 years from the known age. The method underestimated the age of individuals by an average of 4.3 years. An intra‐observer error of 6.6% suggests that the method can be performed with precision. Correlation and regression analysis found that the sacral traits used in the Passalacqua (J Forensic Sci, 5, 2009, 255) method did not have a strong relationship with age or an ability to strongly predict age. Overall, the method was not practical for use in a forensic context due to the broad age ranges, despite the high accuracy and low intra‐observer error.     

纤维联接蛋白的析出与大鼠皮肤早期损伤的时间关系

采用免疫组化(PAP)方法,检测大鼠皮肤损伤区的FN,发现在生前创伤后15min,创壁FN即呈明确阳性;随着伤后经历时间的延长,创壁FN逐渐增多,并滑创壁呈条带状沉积;而在死后5min的创伤,创壁FN则呈阴性。本文为区别生前与死后皮肤创伤提出了一种新的方法。     

第三磨牙萌出情况调查研究

目的为满足应用牙齿萌出时间推测年龄的需要。方法采用帕尔曼牙位标志法记录,对1582名16-23岁学生进行调查。结果随着年龄的增加,4枚第三磨牙均末萌出的呈递减状态,而4枚均萌出的则呈递增状态。萌出1枚的为10.11%,萌出2枚的为13.27%,萌出3枚的为7.96%,萌出4枚为18.90%,4枚均未萌出的为49.75%。结论本组调查数据填补了有关资料的不足,为法医学推测年龄提供参考资料。