Objective To investigate the loci in the STRtyper-21G kit that are prone to tolerance mismatches when compared with the GlobalFilerTM kit and the PowerPlex? 21 kit,and to analyze the underlying causes.Methods A total of 5,870 database comparison reports involving STRtyper-21G profiles and other autosomal STR kits were examined for identity alignment.Samples showing mismatched loci were re-tested using the STRtyper-21G,GlobalFilerTM,and PowerPlex? 21 kits.For loci with mismatches,primers were redesigned and sequencing was performed.Results Eight mismatched samples(8/5 870)were identified,involving the loci D18S51,D8S1179,and D2S1338.Sequencing revealed that the allele dropout at D18S51 was due to a G→A mutation at the 79th base upstream of the core sequence;at D8S1179,a C→A mutation at the 4th base upstream;and at D2S1338,a C→T mutation at the 22nd base downstream.Conclusion All mismatches were attributable to mutations in primer binding regions.These findings provide reference for interpreting mismatch results in the STRtyper-21G database.When mismatches occur at these loci and the profiles are homozygous,exclusion conclusions should be made with caution.

Objective To analyze changes in intestinal microbiota composition and metabolites in mice with nitrous oxide poisoning using 16S rDNA sequencing and metabolomics,and to examine correlations between gut microbes and metabolites in order to explore the mechanisms of nitrous oxide poisoning.Methods C57BL/6 mice were randomly divided into a control group and a nitrous oxide poisoning group(n=6).The poisoning group was exposed to 90,000 ppm nitrous oxide twice daily for 1 h over 28 days,while the control group was exposed to air.Fecal samples were collected 24 h after the last exposure.16S rDNA sequencing was used to analyze structural differences in microbial communities and identify significantly different taxa.Metabolomics analysis was performed to detect changes in fecal metabolites and identify differential metabolites.Correlation analysis was conducted between differential microbiota and metabolites.Results 16S rDNA sequencing showed that the poisoning group had increased microbial abundance compared with controls,while species diversity remained unchanged.Significant differences were observed in gut microbiota structure between groups.Metabolomics identified 112 differential metabolites related to nitrous oxide poisoning,mainly involving the cAMP signaling pathway and sphingolipid metabolism.Spearman correlation analysis revealed a strong association between differential microbiota and differential metabolites.Conclusion Nitrous oxide poisoning alters the structure and metabolic profiles of intestinal microbiota.Changes in microbial abundance affect multiple metabolic pathways,which may be related to damage to the nervous and hematological systems.These findings provide a basis for further research on the mechanisms of nitrous oxide poisoning and for clinical treatment.

Objective To identify key proteins associated with sudden cardiac death(SCD)caused by lethal arrhythmia and to explore their potential molecular mechanisms through integrated proteomic analysis,data mining,and bioinformatics.Methods A lethal arrhythmia model was established in 8-week-old male Sprague-Dawley rats,which were divided into an arrhythmia group and a control group.Proteomic techniques were applied to identify and quantify proteins in left ventricular myocardial tissue,and differentially expressed proteins related to arrhythmia were screened.Key proteins were further identified through comparison with target proteins in databases combined with joint analyses.Bioinformatics methods were then used to investigate potential molecular mechanisms.Results A total of 356 differentially expressed proteins were identified,including 189 upregulated and 167 downregulated.Association analysis with target gene proteins identified 71 key proteins,and a protein-protein interaction network was constructed.GO enrichment and KEGG pathway analyses indicated that these key proteins were primarily involved in ion channel dysfunction,enhanced oxidative stress,and autonomic nervous system imbalance.Conclusion This study,through the integration of proteomics,data mining,and bioinformatics,revealed critical molecular mechanisms underlying SCD associated with lethal arrhythmia.These findings provide new perspectives and potential biomarkers for forensic identification and research on the mechanisms of death.

This study introduces the development of a 96-channel genetic analyzer and its application in forensic medicine.The instrument integrates a fluorescence excitation system,a fluorescence spectral imaging system,and a data acquisition and analysis system,enabling the simultaneous detection of 96 DNA samples.Performance validation in forensic science demonstrated that the analyzer can resolve DNA fragments differing by 1 bp,with accurate DNA typing and a detection sensitivity of 0.125 ng,while maintaining good repeatability.The system can effectively process various forensic samples,including blood cards,saliva cards,and shed cell swabs.In practical applications,the analyzer has significantly improved detection efficiency and shown excellent performance.Looking forward,by broadening the detection range of the nine-color fluorescence spectrum and enhancing the level of data intelligence,the instrument is expected to further strengthen its high-throughput multi-locus detection capability and efficiency,providing more powerful technical support for forensic DNA analysis.

The widespread abuse and high fatality rate of fentanyl and its analogs have posed a severe threat to global public health and safety.Metabolomics has emerged as a research hotspot in forensic science,as it enables the construction of in vivo models of drug toxicity mechanisms at the molecular level without direct drug detection,thereby elucidating metabolic pathways and evaluating toxic effects.Based on recent studies,this paper reviews commonly used strategies for metabolomics research and summarizes advances regarding endogenous biomarkers,metabolites,and toxicity mechanisms of fentanyl analogs,providing a reference for the application of metabolomics in the detection and control of these substances.

In the judicial appraisal of medical injury related to retinopathy of prematurity(ROP),evaluating the loss of visual rehabilitation opportunities for premature infants is crucial for determining liability.Based on the pathogenesis and progression of ROP,and with reference to diagnostic and treatment standards such as the Chinese Guidelines for Screening Retinopathy of Premature Infants(2014),we attempted to establish a multidimensional quantitative analysis framework that incorporates high-risk factor identification,fault-causation analysis,and loss-of-chance quantification.This framework provides a standardized and quantifiable technical pathway for the rational evaluation of rehabilitation opportunity loss in ROP-related medical injury identification.

Objective To identify the key points of forensic appraisal in ophthalmic medical-injury compensation cases and propose targeted measures to prevent disputes.Methods A retrospective analysis was conducted of the appraisal conclusions from 15 ophthalmology medical-injury liability lawsuits handled at a single tertiary hospital over the past five years.We summarized the constitutive characteristics of liability cases,causes of medical injury,and issues encountered during appraisal.Results Among cases undergoing medical-injury liability appraisal,retinal diseases and ocular tumors predominated.The main issues included inadequate informed consent,failure to exercise due care during surgery/treatment,non-standard medical record documentation,insufficient attention to medical risks,and inadequate clinical assessment.Conclusions By summarizing common faults in ophthalmic disputes and problems revealed by forensic appraisal,targeted responses can be implemented to ensure patient safety and promote high-quality medical services.

Objective Piperazine derivatives are a group of emerging psychoactive substances with excitatory and hallucinogenic effects on the central nervous system.This study established a high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)screening method for the detection of 40 piperazine compounds in urine.Methods A 200 μL urine sample(spiked with an internal standard at 1 ng/mL)was subjected to liquid-liquid extraction with ethyl acetate.After nitrogen evaporation,the residue was redissolved in 200 μL methanol and injected for analysis.Separation was performed on a Waters Acquity UPLC? HSS T3 column(100 mm × 2.1 mm,1.8 μm).The mobile phase consisted of(A)20 mmol/L ammonium acetate buffer containing 0.1％formic acid and 5％acetonitrile,and(B)acetonitrile.Gradient elution was applied,and detection was carried out in multiple reaction monitoring(MRM)mode.Quantification was achieved using an internal standard calibration curve.Results The 40 piperazine substances demonstrated good linearity within the range of 1-50 ng/mL,with correlation coefficients of 0.995-0.998.The extraction recovery ranged from 51.51％to 104.1％.Intra-day precision was below 5％,while inter-day precision ranged from 1.61％to 10.17％.Accuracy was between-7.84％and 8.77％.The limits of detection were 0.2-1 ng/mL,and the limit of quantification was 1 ng/mL.Conclusion The proposed method requires only a small sample volume,exhibits high sensitivity,selectivity,and stability,and offers short run times.It is suitable for the qualitative and quantitative determination of piperazine derivatives in urine in forensic toxicology practice.

Objective To establish a rapid on-site detection method for methamphetamine(MA)based on surface-enhanced Raman spectroscopy(SERS).Methods Laboratory-synthesized colloidal silver nanoparticles(AgNPs)were employed as SERS substrates to rapidly detect methamphetamine in typical crime scene matrices,including beer,cigarette ash,and plastic containers.Results The method requires no sample pretreatment,is simple to operate,and offers high sensitivity with fast detection speed.The limit of detection(LOD)reached 10 ppb(signal-to-noise ratio,S/N＞3).The qualitative results of methamphetamine analysis from forensic case samples were highly consistent with gas chromatography-mass spectrometry(GC-MS)findings.Conclusion Methamphetamine is frequently encountered in illicit settings and criminal activities.This study achieved rapid detection of methamphetamine in complex matrices(beer,cigarette ash,and plastic containers),demonstrating good application prospects in practice and providing important value for law enforcement,public safety,and criminal investigation.

Meat food is an important part of people's dietary supplements,but in recent years,meat adulteration cases are hidden and frequent,which seriously affects people's health and destroys the fairness of the market.Based on this,this paper analyses the development trend of meat adulteration and the current meat adulteration detection technology is summarized,combed in detail the use of the most widely used real-time fluorescence quantitative PCR technology application of the status quo and challenges to help real-time fluorescence quantitative PCR technology testing in meat adulteration evidence testing to the direction of more high detection efficiency and higher accuracy development.