Forensic Analysis of Human Autopsy Tissue for the Presence of Polydimethylsiloxane (Silicone) and Volatile Cyclic Siloxanes using Macro FT‐IR,FT‐IR Spectroscopic Imaging and Headspace GC‐MS

This study describes effective and straightforward primary and secondary methods for the detection of silicone in human autopsy tissue. The primary method is polydimethylsiloxane (PDMS) specific and employs either macro‐attenuated total reflection Fourier transform infrared (ATR‐FT‐IR) spectroscopy for samples with a high PDMS concentration (relative to that of the matrix) or micro‐FT‐IR spectroscopic imaging in a reflection/absorption modality for samples with a low PDMS concentration. Although the secondary method is not PDMS specific, it employs headspace gas chromatography with mass spectrometric detection (HS/GC‐MS) for the detection of low molecular weight volatile cyclic siloxanes (VCS), which are characteristic marker compounds for PDMS. Overall, the combined results from the primary and secondary analyses provide reliable evidence for the presence of silicone.     

The Effect of Flunitrazepam (Rohypnol®) on the Development of Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) and its Implications for Forensic Entomology

This study investigated the potential effects of flunitrazepam (known as “date rape drug”) on the developmental cycle of Chrysomya megacephala, an important forensic species, and their possible implications for the calculation of the PMI. A 1050 C. megacephala eggs were divided into five groups with seven replications each. The eggs were placed on artificial diet prepared with four drug concentrations of flunitrazepam (4, 8, 16, and 32 ng/g), besides the control group (prepared with water). Were evaluated the potential effects on development time, weight gain, and mortality during the cycles. The drug had no significant effect on development time or mortality although it did affect the weight of the pupae and adults (Kruskal–Wallis, p < 0.05). The result can be deduced that the determination of the postmortem interval is not affected.     

Evaluation of Virulence Factors and Antifungal Susceptibility in Yeast Isolates from Postmortem Specimens

Invasive fungal infections are a leading cause of morbidity and mortality in immunocompromised patients, especially in cases requiring a prolonged stay in the intensive care unit. A total of 99 yeast strains were isolated from 42 postmortem cases. In this study, virulence factors and antifungal susceptibility of these species were evaluated. The isolates were identified as Candida albicans (54), C. tropicalis (15), C. glabrata (12), C. parapsilosis (6), C. lipolytica (3), C. utilis (3), C. krusei (2), C. kefyr (1), and Cryptococcus neoformans (3). The most commonly isolated species was C. albicans, and no resistant species were determined. Despite the equal number of specimens, no secretion of significant virulence factors was associated with the postmortem specimen in the Candida species. Postmortem fungal investigations in forensic autopsies are useful in explaining cause of death in such cases, also may lead to protocols for the treatment of fungal infections and contribute to fungal pathogenesis and epidemiological data.     

Homicidal Poisoning in China Using Several Anesthetic Drugs

The authors describe a case of a well‐designed homicidal poisoning in China. A male was treated with starvation, intravenous fluids and antibiotics while in the hospital for acute diarrhea. He suddenly suffered from shortness of breath and subsequently died. A forensic autopsy was carried out, and several specimens were collected for toxicological screening. Propofol was tentatively identified in the blood by GC‐MS. Based on the presence of propofol in the blood, a suspect confessed that two other drugs, namely midazolam and vecuronium, were involved in this murder. Analytical drug quantification was then performed by GC‐MS and LC‐MS/MS. Blood analysis revealed the following: propofol at 0.5 μg/mL, midazolam at 0.098 μg/mL, and vecuronium at 0.10 μg/mL. These results suggest that the cause of death was respiratory depression due to the acute combined effect of several anesthetic drugs administered by the victim's companion.     

Popliteal Vein Blood Sampling and the Postmortem Redistribution of Diazepam,Methadone, and Morphine

Postmortem redistribution (PMR) refers to the site‐ and time‐related blood drug concentration variations after death. We compared central blood (cardiac and subclavian) with peripheral blood (femoral and popliteal) concentrations of diazepam, methadone, and morphine. To our knowledge, popliteal blood has never been compared with other sites. Intracardiac blood (ICB), subclavian blood (SB), femoral blood (FB), and popliteal blood (PB) were sampled in 30 cases. To assess PMR, mean concentrations and ratios were compared. Influence of postmortem interval on mean ratios was also assessed. Results show that popliteal mean concentrations were lower than those for other sites for all three drugs, even lower than femoral blood; mean ratios suggested that the popliteal site was less subject to PMR, and estimated postmortem interval did not influence ratios except for diazepam and methadone FB/PB. In conclusion, our study is the first to explore the popliteal site and suggests that popliteal blood is less prone to postmortem redistribution.     

不同温度下大鼠脑组织RNA降解与早期PMI的相关性

目的探讨大鼠脑组织8种RNA指标,在不同温度下的表达水平与早期死亡时间(PMI)的相关性。方法将222只SD大鼠随机分为对照组(死后0 h)和4个实验组,实验组断颈处死后分别置于5℃、15℃、25℃和35℃的环境中,于死后1~24 h内9个时间点提取脑组织RNA,利用实时荧光定量PCR技术检测8种RNA指标(β-actin、GAPDH、RPS29、18S rRNA、5S rRNA、U6 snRNA、miRNA-9及mi RNA-125b)的表达水平,ge Norm软件选取合适内参,SPSS软件对内参标准化RNA指标进行回归分析,R软件构建推断PMI的数学模型,另选6只已知PMI的SD大鼠予以验证。结果 5S rRNA、miR-9和mi R-125b表达稳定,可作为内参指标。β-actin和GAPDH具有良好的时序性降解规律,在24 h内随PMI延长不断降解。R软件拟合得ΔCt值随PMI和温度变化的数学模型可用以推断PMI。运用β-actin和GAPDH验证模型的平均误差率分别为14.1%和22.2%。结论β-actin和GAPDH表达水平与PMI和环境温度相关性良好。本研究建立的数学模型可为温度变化条件下的早期PMI推断提供参考。     

Classical stimulants in Dallas County: A retrospective review of toxicological,seized drug,and demographical data from 2017 to 2022

Cocaine and methamphetamine remain highly abused drugs in the United States due to their euphoric effects. This study examines classical stimulant casework, defined as cases positive for methamphetamine and/or cocaine, received by the Toxicology Laboratory and the Drug Analysis Laboratory at the Dallas County Southwestern Institute of Forensic Sciences from local law enforcement agencies and/or the Office of the Medical Examiner (OME) between January 1, 2017, and December 31, 2022. Methamphetamine positivity increased from 10.4% to 20.3% in the Toxicology Laboratory over the 6 years, whereas cocaine positivity remained relatively stable at approximately 17%. Similarly, in the Drug Analysis Laboratory, the methamphetamine positivity rate changed from 24.8% to 33.2%, whereas cocaine identification remained stable at approximately 20%. Blood concentrations of methamphetamine in OME cases ranged from 10.1–42,740.0 ng/mL while they were lower in DWI casework ranging from 10.2–2385.0 ng/mL. The blood concentration trends of cocaine were similar to methamphetamine, with OME casework ranging higher (10.0–24,501.0 ng/mL) than DWI casework (10.2–371.6 ng/mL). Polydrug use was evident for both methamphetamine and cocaine in postmortem cases, and the top three most frequently co-occurring drug/drug class were opioids/opiates, cannabinoids, and ethanol. The results from this study aid in the understanding of historical usage trends of cocaine and methamphetamine in Dallas County and how those trends have changed over time as newer stimulant drugs have emerged.     

Hyperspectral imaging in forensic science: An overview of major application areas

Analysis of evidence is a challenge. Crime scene materials are complex, diverse, sometimes of an unknown nature. Forensic science provides the most critical applications for their examination. Chemical tests, analytical methods, and techniques to process the evidence must be carefully selected by the forensic scientist. Ideally, it may be interpreted, analyzed, and judged in the original context of the crime scene. In this sense, hyperspectral imaging (HSI) has been employed as an analytical tool that maintains the integrity of the samples/objects for multiple and sequential analysis and for counter-proof exams. This paper is an overview of forensic science trends for the application of HSI techniques in the last ten years (2011–2021). The examination of documents was the main area of exploration, followed by bloodstain analysis aging process; trace analysis of explosives and gunshot residue. Chemometric tools were also addressed since they are crucial to obtain the most important information from the samples. There are great challenges in applying HSI in forensic science, but there have been clear technological and scientific advances, and a solid foundation has been built for the use of HSI in real-life cases.     

骨折经过时间推断的研究现状与展望

Gong Wei;Wang Yantao(The PublicSecurity Bureau of Shiyan,Shiyan,Hubei,442000)     

Report of Increasing Overdose Deaths that include Acetyl Fentanyl in Multiple Counties of the Southwestern Region of the Commonwealth of Pennsylvania in 2015–2016

Acetyl fentanyl is a Schedule I controlled synthetic opioid that is becoming an increasingly detected “designer drug.” Routine drug screening procedures in local forensic toxicology laboratories identified a total of 41 overdose deaths associated with acetyl fentanyl within multiple counties of the southwestern region of the state of Pennsylvania. The range, median, mean, and standard deviation of blood acetyl fentanyl concentrations for these 41 cases were 0.13–2100 ng/mL, 11 ng/mL, 169.3 ng/mL, and 405.3 ng/mL, respectively. Thirty‐six individuals (88%) had a confirmed history of substance abuse, and all but one case (96%) were ruled multiple drug toxicities. This report characterizes this localized trend of overdose deaths associated with acetyl fentanyl and provides further evidence supporting an alarmingly concentrated opiate and opioid epidemic of both traditional and novel drugs within this region of the United States.