To destroy snail mail: Is this the sole solution for anthrax contaminated letters?

Suspicious packages, strange addresses on envelopes and/or the presence of particular powders: these are the most popular aspects of letters containing Bacillus anthracis. Since the World Trade Center tragedy, alarmism about chemical or biological attacks is always in force. The Italian Ministry of Foreign Affairs introduced new procedures to be followed in case suspected anthrax letters are identified (Ministry of Health PROT. 400.3/120.33/4786 of 23/10/2001). Scientists have to collect samples from surfaces and infectious waste have to be placed in autoclavable bags for decontamination. After the sterilization, mails and packages are burnt thus eliminating every biological trace present on their surface. As a matter of fact, after sterilization, DNA is still present and can be analyzed for forensic purposes: for this reason, here we report on the importance of preserving sterilized substrates. We recreated false infected mails with biological traces on their surfaces, sterilized them and, subsequently, we took samples of biological stains and processed them for DNA quantification and typing. We recreate different time conditions consistent with those of the postal service too. Real-Time PCR and DNA typing showed that, even if sterilization destroys the bacillus, human genomic traces still persist and we obtained both complete and partial profiles of samples’ donors. To conclude, the problem of anthrax contaminated letter call for peculiar and standardized procedures; nonetheless, we show that burning evidences after the sterilization process does not appear to be the best solution since there is a loss of biological material which could be decisive for forensic purposes.     

The use of a quantitative structure-activity relationship (QSAR) model to predict GABA-A receptor binding of newly emerging benzodiazepines

The illicit market for new psychoactive substances is forever expanding. Benzodiazepines and their derivatives are one of a number of groups of these substances and thus far their number has grown year upon year. For both forensic and clinical purposes it is important to be able to rapidly understand these emerging substances. However as a consequence of the illicit nature of these compounds, there is a deficiency in the pharmacological data available for these ‘new’ benzodiazepines. In order to further understand the pharmacology of ‘new’ benzodiazepines we utilised a quantitative structure-activity relationship (QSAR) approach. A set of 69 benzodiazepine-based compounds was analysed to develop a QSAR training set with respect to published binding values to GABA_A receptors. The QSAR model returned an R² value of 0.90. The most influential factors were found to be the positioning of two H-bond acceptors, two aromatic rings and a hydrophobic group. A test set of nine random compounds was then selected for internal validation to determine the predictive ability of the model and gave an R² value of 0.86 when comparing the binding values with their experimental data. The QSAR model was then used to predict the binding for 22 benzodiazepines that are classed as new psychoactive substances. This model will allow rapid prediction of the binding activity of emerging benzodiazepines in a rapid and economic way, compared with lengthy and expensive in vitro/in vivo analysis. This will enable forensic chemists and toxicologists to better understand both recently developed compounds and prediction of substances likely to emerge in the future.     

生物科技相关法律问题与《禁止生物武器公约》

生物技术所具有的人为改变生物自然性状的能力,也对生物多样性的保护构成了前所未有的威胁,并与人类社会的伦理观念发生了冲突。在专家学者、政府部门和各界的共同努力之下,发达国家目前已初步建立了生物安全规范体系。在国际范围内,联合国环境规划署制定了《国际生物技术安全准则》。为此, 我们必须加强对生物科技相关法律问题的研究。科学上的任何一样进步,人类都可以拿来作为武器。随着生物技术的飞速发展,在不久的将来很有可能会研制出杀伤力更隐蔽的新一代生物武器——基因武器。《禁止生物武器公约》对于禁止生物武器、防止生物武器扩散发挥了积极作用,已成为国际军控条约体系和以联合国为中心的集体安全框架的重要组成部分。中国政府一贯主张全面禁止和彻底销毁包括生物武器在内的一切大规模杀伤性武器,高度重视公约在维护世界和平与安全方面的积极作用。     

痛经合剂治疗原发性痛经机制的实验研究

目的:探讨痛经合剂治疗原发性痛经的药理学机制。方法:观察痛经合剂对正常雌性大鼠体外子宫平滑肌和催产素所致的子宫平滑肌收缩的作用,及其对雌性小鼠痛经模型和醋酸所致小鼠疼痛和对小鼠的催眠作用。结果:痛经合剂能显著抑制正常大鼠体外子宫平滑肌和催产素所致的体外子宫平滑肌的收缩,明显减少雌性小鼠痛经模型和醋酸所致小鼠扭体反应次数,显著增加戊巴比妥阈下发生睡眠的小鼠个数。结论:痛经合剂具有的解痉、镇痛、镇静作用,是其治疗原发性痛经的药理学依据。     

技术侦查的认知模式研究

侦查现代化是一个内涵丰富的概念,侦查认知模式的现代化是题中应有之意。技术侦查是现代侦查的发展趋势,技术侦查的认知模式主要包括时空认知、信息认知、生物机能认知三种模式。在新的司法理念和证据观念下探讨这些认知模式,揭示其蕴涵的科学性和实践运用的局限对正确认识科技在侦查认识中的作用是十分重要的。     

固相微萃取技术的进展

衍生化顶空固相微萃取是将样品衍生化和顶空固相微萃取结合,使顶空固相微萃取技术扩展到难挥发性样品分析中。作者就衍生化顶空固相微萃取的发展历史、衍生化反应类型,以及在生物基质、水基质内痕量物质检测研究中的应用进行了综述。     

生物组织检材内异烟肼的薄层色谱扫描检测研究──附1例异烟肼中毒死亡者体内分布报告

改进血清中异烟肼的提取方法，建立了生物组织检材内异胭肼的提取和薄层色谱扫描检测方法，线性范围为2～32ug／ml或g，检出限为0．5ug／ml或g。l例异烟擀中毒死亡者体内异烟肼分布：肾31．6mg／100g、肝26．6mg／100g、脾22．1mg／100g、心21．3mg／100g、胃16．6mg／100g、脑15．5mg／100m、肺12．6mm／100g、小脑11．7mm／100g和10.5mm／100ml。     

An innovative transfer DNA experimental design and qPCR assay: Protocol and pilot study

Forensic “touch” DNA samples are low-quantity samples that are recovered from surfaces that have been touched by single or multiple individuals. These samples can include DNA from primary contributors who directly touched the surface, as well as secondary contributors whose DNA was transferred to the surface through an intermediary. It is difficult to determine the type of transfer, or how often and under what conditions DNA transfer occurs. In this paper, we present an innovative protocol that combines (1) a paired male and female transfer DNA experimental design in which the presence of male DNA indicates secondary transfer and (2) a cost-effective quantitative PCR (qPCR) assay of a sex-specific region in the Amelogenin gene to detect male and female DNA. We evaluate the ability of the Amelogenin qPCR assay to detect low concentrations of male and female DNA in mixed samples. We also test experimental DNA samples using our transfer DNA protocol to differentiate primary and secondary DNA transfer. Male DNA was detected in the majority of known mixed samples, even in samples with 4× more female DNA—this result demonstrates the ability to detect low concentrations of male DNA and the presence of secondary transfer DNA in our experimental design. Primary DNA transfer was detected in 100% of our experimental trials and secondary DNA transfer was detected in 37.5% of trials. Our innovative protocol mimics realistic case scenarios to establish rates of primary and secondary DNA transfer in an inexpensive and simplified manner.     

Estimating the Number of Contributors to Forensic DNA Mixtures: Does Maximum Likelihood Perform Better Than Maximum Allele Count?

Abstract: Determining the number of contributors to a forensic DNA mixture using maximum allele count is a common practice in many forensic laboratories. In this paper, we compare this method to a maximum likelihood estimator, previously proposed by Egeland et al., that we extend to the cases of multiallelic loci and population subdivision. We compared both methods’ efficiency for identifying mixtures of two to five individuals in the case of uncertainty about the population allele frequencies and partial profiles. The proportion of correctly resolved mixtures was >90% for both estimators for two‐ and three‐person mixtures, while likelihood maximization yielded success rates 2‐ to 15‐fold higher for four‐ and five‐person mixtures. Comparable results were obtained in the cases of uncertain allele frequencies and partial profiles. Our results support the use of the maximum likelihood estimator to report the number of contributors when dealing with complex DNA mixtures.     

Evaluation and classification of fentanyl-related compounds using EC-SERS and machine learning

Multiple analytical techniques for the screening of fentanyl-related compounds exist. High discriminatory methods such as GC–MS and LC–MS are expensive, time-consuming, and less amenable to onsite analysis. Raman spectroscopy provides a rapid, inexpensive alternative. Raman variants such as electrochemical surface-enhanced Raman scattering (EC-SERS) can provide signal enhancements with 10¹⁰ magnitudes, allowing for the detection of low-concentration analytes, otherwise undetected using conventional Raman. Library search algorithms embedded in instruments utilizing SERS may suffer from accuracy when multicomponent mixtures involving fentanyl derivatives are analyzed. The complexing of machine learning techniques to Raman spectra demonstrates an improvement in the discrimination of drugs even when present in multicomponent mixtures of various ratios. Additionally, these algorithms are capable of identifying spectral features difficult to detect by manual comparisons. Therefore, the goal of this study was to evaluate fentanyl-related compounds and other drugs of abuse using EC-SERS and to process the acquired data using machine learning—convolutional neural networks (CNN). The CNN was created using Keras v 2.4.0 with Tensorflow v 2.9.1 backend. In-house binary mixtures and authentic adjudicated case samples were used to evaluate the created machine-learning models. The overall accuracy of the model was 98.4 ± 0.1% after 10-fold cross-validation. The correct identification for the in-house binary mixtures was 92%, while the authentic case samples were 85%. The high accuracies achieved in this study demonstrate the advantage of using machine learning to process spectral data when screening seized drug materials comprised of multiple components.