法医学杂志最新文献

Objectives: To evaluate the forensic application value of used dental floss as a source of biological evidence for individual identification by analyzing the effects of dental floss sample collection methods, DNA extraction methods, preservation conditions, and sampling sites on the success rate of STR typing.

Methods: Dental floss samples were collected using three techniques: direct cutting, cotton swab wiping, and flocked swab wiping, respectively. DNA was extracted respectively by the Chelex, spin column-based and magnetic bead-based methods. DNA quantification and STR typing were performed using the Qubit kit and FGI HumDNA Typing kit (Platinum), respectively. Storage environments (temperature and humidity, ultraviolet radiation) and sampling locations (the floss part, the handle part) on DNA quantity and STR typing were evaluated.

Results: Through conducting a statistical analysis of three key indicators of average DNA mass concentration, STR locus detection rate, and typing accuracy rate, the direct cutting method demonstrated the highest efficacy, followed by cotton swab wiping mothed, and the flocked swab wiping method had the lowest efficacy. Direct cutting yielded an average DNA mass concentration greater than (4.94±1.87) ng/μL, with STR locus detection and accuracy rates of 100%. Bead-based DNA extraction method produced superior DNA concentration and quality compared to spin column-based and Chelex methods, regardless of whether the sampling technique used. Preservation conditions had a significant impact on the DNA analysis of samples. Particularly, the STR typing accuracy of samples preserved at 55 ℃/50%RH for 35 days dropped to (81.82±12.31)%, and that of samples exposed to ultraviolet radiation for 12 h dropped to (55.46±34.31)%. DNA concentration from the handle part of dental floss was extremely low, with an STR typing accuracy of only (30.91±27.35)%.

Conclusions: Using cotton swabs to wipe or directly cutting the thread of dental floss samples, and combining this approach with the magnetic bead method for DNA extraction, can best guarantee the concentration and quality of DNA. In addition, samples should be stored in low-temperature, low-humidity environment, protected from light and ultraviolet radiation.

At present, the drug substitutes represented by new psychoactive substances are gradually becoming popular, leading to an increasing demand for identifying novel drugs with unknown structures in drug investigation. Nuclear magnetic resonance (NMR) spectroscopy is an important tool for analyzing molecular structures. In the absence of standard substances, quantitative NMR (qNMR) can undertake the quantitative analysis of target substances in complex mixtures and has unique advantages in the research of new drugs and their precursor drugs. Due to the limitations of the site and maintenance costs, as well as relatively complex operation, high-field superconducting NMR is less commonly applied in drug research. The desktop low‑field NMR developed in recent years provides a new alternative solution. Due to the use of permanent magnets, its size is reduced, and the operation and maintenance costs are lowered. It has been widely used in various research fields. This article reviews the development of low-field NMR technology, summarizes the application of desktop low-field NMR in screening and identification of suspicious substances, rapid content determination, analysis of drug manufacturing processes and synthetic routes, and correlation traceability. It also looks forward to the prospects and development directions of this technology in drug research, aiming to provide a reference for researchers who work in analytical chemistry and drug research.

Objectives: To analyze the literature in the field of body fluid identification collected in the Web of Science Core Collection (WoSCC) database from 2000 to 2023, and explore the research status, hotspots and development trends in this field.

Methods: The CiteSpace software was utilized to conduct a visual analysis of the literature in the field of body fluid identification included in the WoSCC database from 2000 to 2023. Meanwhile, a bibliometric analysis of the annual publication volume, journal distribution, national contribution, research institutions, author collaboration, and keywords of the literature was conducted.

Results: A total of 715 papers on forensic body fluid identification were included, and the annual publication volume showed a continuous and stable growth. Among the 55 countries (regions) that published papers, the United States ranked first with 174 papers, followed by China with 107 papers. In terms of journal distribution, Forensic Science International: Genetics had the largest number of papers, which accounted for 20% of the total papers. In terms of author collaboration, a total of 2 079 authors participated in body fluid identification research, and the author collaboration network showed a clearly clustered distribution. The keywords analysis revealed that research hotspots focused on traditional methods, specific RNA molecular markers, DNA methylation, spectroscopy, and the application of microbiomics.

Conclusions: Research in the field of forensic body fluid identification is thriving, and research institutions and teams should strengthen their collaboration. Establishing unified result interpretation standards and systems and exploring the multiple biomarkers combined application methods will be the research hotspots and important directions for future research in this field.

Caenorhabditis elegans, as an emerging model organism, has been widely used in multiple disciplines such as medicine, life science, and environmental science in recent years, due to its characteristics of short life cycle, clear genetic background, highly conserved evolution, complete genome analysis and excellent fitting between experimental data and human results. It also shows unique advantages in the field of toxicology. This paper summarizes its advantages in toxicological research starting from the biological characteristics of C. elegans, introduces the toxicological research methods and progress based on the C. elegans model, focuses on demonstrating its applications in environmental forensic medicine and forensic toxicology, and looks forward to the application of the relevant results in the field of forensic science.