Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time‐dependent changes in melanin‐derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20–22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time‐dependent decay of melanin‐derived radicals. The half‐life of eumelanin‐derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non‐invasive, non‐destructive, and highly specific EPR technique.     

Fetal Age Estimation Using Orbital Measurements: 3D CT-Scan Study Including the Effects of Trisomy 21

Abstract:  This study evaluates a new method of fetal age estimation based on orbital measurement and including the potential trisomy 21 of the fetus. Six orbital and one facial CT-scan measurements were taken on 71 fetuses ranging from 14 to 41 weeks of gestational age. Forty-eight fetuses were "normal" and 23 fetuses presented the Down syndrome (trisomy 21). The anatomy/imagery correspondence was evaluated comparing our results to those obtained by direct bone measurements on the same fetuses and revealed no significant differences between the two kinds of measurements. Moreover, a multiple linear stepwise regression was realized to estimate fetal age and showed that the "trisomy 21 parameter" is not conserved in the final determination model. Therefore, we conclude that the good radio-anatomical correspondence offers an interesting alternative to direct bone measurement (necessitating dissections) and allows a reliable fetal age determination, whatever is the trisomy 21 condition of the fetus.     

Ethyl glucuronide: unusual distribution between head hair and pubic hair

Ethyl glucuronide (EtG) is a minor metabolite of ethanol that can be detected in hair. In some specific situations, head hair can be missing, and therefore, alternative anatomical locations of hair are of interest. In this study, paired hair specimens (head hair and pubic hair) from eight social drinkers were analyzed for EtG. Each sample was decontaminated by two dichloromethane bathes (5 ml) for 2 min. After cutting into small pieces, about 50 mg of hair was incubated in 2 ml water in the presence of 10 ng of EtG-d5, used as internal standard and submitted to ultra-sonication for 2 h. The aqueous phase was extracted by SPE using Oasis MAX columns. The hair extract was separated on an ACQUITY BEH HILIC column using a gradient of acetonitrile and formate buffer. Detection was based on two daughter ions: transitions m/z 221-85 and 75 and m/z 226-75 for EtG and the IS, respectively. This laboratory is using a positive cut-off at 50 pg/mg. All eight head hair specimens were negative for EtG at a limit of quantitation fixed at 10 pg/mg. Surprisingly, EtG was identified at high concentrations in pubic hair, in the range 12-1370 pg/mg. It appears, therefore, that it is not possible to document the drinking status of a subject by simply switching from head hair to pubic hair.     

Policing Australia’s ‘heroin drought’: using an agent-based model to simulate alternative outcomes

Our paper examines how street-level drug markets adapt to a macro-level disruption to the supply of heroin, under three experimental conditions of street-level drug law enforcement: random patrol, hot-spot policing and problem-orientated policing. We utilize an agent-based model to explore the relative impact of abstractions of these three law enforcement strategies after simulating an ‘external shock’ to the supply of heroin to the street-level drug market. We use 3 years of data, which include the period of the ‘heroin drought’ in Melbourne (Australia) that commenced in late 2000 and early 2001, to measure changes in a selected range of crime and harm indicators under the three policing conditions. Our results show that macro-level disruptions to drug supply have a limited impact on street-level market dynamics when there is a ready replacement drug. By contrast, street-level police interventions are shown to vary in their capacity to alter drug market dynamics. Importantly, our laboratory abstraction of problem-orientated policing is shown to be the optimal strategy to disrupt street-level injecting-drug markets, reduce crimes and minimize harm, regardless of the type of drug being supplied to the market.

体系、社会和国家:理解《美韩自由贸易协定》

2007年6月,美韩双方签署了《美韩自由贸易协定》。美韩之间为什么要签署该协定?该协定对两国国内分别产生了哪些影响?该协定为何至今没能获得美国国会的通过?针对上述问题,本文结合美国贸易政策理论,从体系、国家和社会三个层面对其进行了分析。《美韩自由贸易协定》的签署及其实施,在体系层面上将会为双方带来经济、政治和战略上的多重收益,而在社会层面上却产生了不同的反应。尽管由于国内经济困难和利益集团的掣制使得协定的通过还面临不小的阻力,但基于协定所蕴含的重要价值和两国政府对此认识的高度一致,协定获得通过只是时间上的问题。     

东亚-北美经济失衡与再平衡分析

本文从国别结构和产品结构分析了20世纪90年代以来东亚—北美经济失衡的变化,认为美国贸易逆差不断扩大是其对外产业转移的结果,东亚地区贸易顺差与日俱增是其承接产业转移的结果。其中,东亚内部再次产业转移导致中国顺差迅速膨胀。为了实现东亚—北美经济再平衡,美国需要采取一些措施扩大出口,控制过度的信贷消费,并对美元采取更加负责的政策;东亚地区需要努力实现由外需驱动型向内需驱动型增长方式的转变,加快产业调整与升级,并把产业链向其他地区延伸。     

Evaluation and applicability of Alere iCup DX 14 for rapid postmortem urine drug screening at autopsy

Performing point‐of‐care urine drug screen testing at autopsy by a forensic pathologist may provide an early indication of the presence of analytes of interest during autopsy. An evaluation for the screening of 14 classes of common drugs of abuse in postmortem urine by the point‐of‐care screening device, Alere iCup DX 14, is presented. One hundred ninety postmortem urine samples were screened with the iCup occurring at autopsy by the forensic pathologist. Positive and negative results obtained from the screening kit were evaluated against confirmatory test results obtained using routine forensic toxicology analyses that employed LC‐MS/MS and GC‐MS to detect a combination of over 85 common drugs of abuse and medications. Sensitivity for each respective iCup drug class ranged from 66% (buprenorphine) to 100% (methadone, tricyclic antidepressants). Specificity for each respective iCup drug class ranged from 89% (benzodiazepines) to 100% (amphetamines, barbiturates, buprenorphine, 3,4‐methylenedioxymethamphetamine, methadone). Positive predictive values ranged from 44% (benzodiazepines) to 100% (amphetamines, barbiturates, buprenorphine, methylenedioxymethamphetamine, methadone), while negative predictive values ranged from 96% (methamphetamine) to 100% (barbiturates, methadone, tricyclic antidepressants). A high false‐positive rate was yielded by the benzodiazepine class. The lack of fentanyl screening in the point‐of‐care device is a significant limitation considering its prolific prevalence in forensic casework. The results obtained in the study should be acknowledged when considering the use of the Alere iCup DX 14 in the context of postmortem casework to help indicate potential drug use contemporaneously with autopsy and when requiring such preliminary results prior to the release of a final forensic toxicology report.     

Homicide by unusual‐edged weapons: Forensic considerations of two cases

Homicide by stab wound is common worldwide. However, the use of unusual edged weapons is rarely reported in the forensic literature. Here, we report two cases of homicide involving a Japanese sword, or katana, and a sickle. Both of these weapons can create either stab or incised wounds with some particularities. In our cases, characteristics of the external wounds, internal injuries, and the depth of penetration raised the possibility of an unusual weapon. Meticulous forensic examination of these injuries (morphological characteristics, depth of penetration, trajectories, and cut marks in the bone) may allow the forensic expert to determine the type of weapon used.     

Identification of furosemide in hair in a post‐mortem case by UHPLC‐MS/MS with guidance on interpretation

Testing for drugs in hair raises several difficulties. Among them is the interpretation of the final concentration(s). In a post‐mortem case, analyses revealed the presence of furosemide (12 ng/mL) in femoral blood, although it was not part of the victim's treatment. The prosecutor requested our laboratory to undertake an additional analysis in hair to obtain information about the use of furosemide. A specific method was therefore developed and validated to identify and quantify furosemide in hair by UHPLC‐MS/MS. After decontamination of 30 mg of hair, incubation in acidic condition, extraction with ethyl acetate, the samples were analyzed by UHPLC‐MS/MS. Furosemide was found in the victim's hair at 225 pg/mg. However, it was not possible to interpret this concentration due to the absence of data in the literature. Therefore, the authors performed a controlled study in two parts. In order to establish the basis of interpretation, several volunteers were tested (four after a single 20 mg administration and twenty‐four under daily treatment). The first part indicated that a single dose is not detectable in hair using our method. The second part demonstrated concentrations ranging from 5 to 1110 pg/mg with no correlation between dosage and hair concentrations. The decedent's hair result was interpreted as repeated exposures. In the case of furosemide analysis, hair can provide information about its presence but cannot give information about dosage or frequency of use.     

Characterization and differentiation of aluminum powders used in improvised explosive devices – Part 1: Proof of concept of the utility of particle micromorphometry

Aluminum (Al) powders are commonly used in improvised explosive devices as metallic fuels, a component of explosive mixtures. These powders can be obtained readily from industrial‐scale and consumer products, and produced using unsophisticated “kitchen chemistry” techniques. This research demonstrates the potential of automated particle micromorphometry for comparisons between known source and questioned Al powders recovered from IEDs, as well as for insight into the method of Al powder manufacture. Al powder samples were obtained from legitimate manufacturers, and 56 samples were produced “in‐house” from Al‐containing spray paints and ball‐milled Al foils. Transmitted light microscope images of Al powder particles were acquired using an automated stage with automated z‐focus; 17 size and shape parameters were measured for all particles. Approximately 37,000–2,500,000 particles/sample were analyzed using an open‐source statistical package with customized code. Dimensionality reduction was required for processing the large datasets: eight of the 17 measured variables were selected based on inspection of the correlation matrix. Data from four subsamples from each of the 56 samples produced using “in‐house” methods were analyzed using ANOVA to assess the within‐ and between‐sample variation. High within‐sample variation was noted; however, ANOVA and post‐hoc Tukey's honestly significant difference (HSD) tests demonstrated that the between‐sample variation was substantially larger than the within‐sample variation. Each sample could be differentiated from all other samples in the test set. Future experiments will focus on ways to reduce the within‐sample variation, and additional statistical and microanalytical methods to classify sources and confidently constrain the method of Al powder manufacture.