Degradation dynamics of cuticular hydrocarbons of empty puparia in forensically important blow fly Lucilia sericata in soil and under room conditions: Insights and machine learning applications

IF 2.6 3区 医学 Q2 CHEMISTRY, ANALYTICAL
Swaima Sharif , Cora Wunder , Mohd Kaleem Khan , Jens Amendt , Ayesha Qamar
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Abstract

Empty puparia, remnants of blow fly larvae cuticles, aid in estimating long-term post-mortem intervals. Assessing alterations in cuticular hydrocarbons (CHCs) composition provides insights into environmental effects on their degradation, enabling age estimation methods for empty puparia found at the crime scene. The current study aimed to investigate the temporal variations of five predominant CHCs of empty puparia of Lucilia sericata (Diptera: Calliphoridae). The study was conducted over six months (180 days) under controlled conditions, comparing the storage of puparia in soil and non-soil pupation medium (room conditions). The five CHCs investigated are- n-pentacosane, n-hexacosane, n-heptacosane, n-octacosane, and n-nonacosane. Gas chromatography-mass spectrometry (GC–MS) was used to analyze the cuticular hydrocarbons after they were extracted in hexane. The findings indicated that the degradation rate of CHCs was influenced by the surrounding environment, with more rapid degradation observed in soil conditions compared to room conditions. This suggests that soil can impact the weathering process of empty puparial cases. To predict the age of the puparial cases, a Support Vector Machine (SVM) analysis was conducted based on the concentrations of hydrocarbons. The SVM models demonstrated promising performance in age prediction, exhibiting high R-squared values and low prediction errors. By highlighting the influence of environmental factors on CHC degradation and demonstrating the efficacy of SVM models in age prediction, this study lays the groundwork for further exploration and development of CHCs as valuable tools in forensic and ecological research.

Abstract Image

在土壤和室内条件下,具有重要法医意义的丝光绿蝇空蛹表皮碳氢化合物的降解动力学:见解和机器学习应用
空的蝇蛹,残馀的蝇幼虫角质层,有助于估计死亡后的长期间隔。评估角质层碳氢化合物(CHCs)组成的变化,可以深入了解环境对其降解的影响,使犯罪现场发现的空蛹的年龄估算方法成为可能。本研究旨在研究绢绿蝇(双翅目:绢绿蝇科)空蛹5种主要CHCs的时间变化。研究在受控条件下进行了6个月(180 天),比较了蛹在土壤和非土壤化蛹介质(室内条件)中的储存情况。所研究的五种CHCs分别是-正五碳烷、正六碳烷、正七碳烷、正八碳烷和正壬碳烷。采用气相色谱-质谱联用(GC-MS)技术对正己烷提取后的表皮烃进行分析。结果表明,CHCs的降解速率受周围环境的影响,在土壤条件下比在室内条件下降解更快。这说明土壤对空蛹壳的风化过程有一定的影响。为了预测puparial病例的年龄,基于碳氢化合物的浓度进行了支持向量机(SVM)分析。支持向量机模型具有较高的r平方值和较低的预测误差,具有较好的年龄预测效果。通过突出环境因素对CHC降解的影响,并证明支持向量机模型在年龄预测中的有效性,为进一步探索和开发CHC作为法医和生态研究中有价值的工具奠定基础。
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来源期刊
Forensic Chemistry
Forensic Chemistry CHEMISTRY, ANALYTICAL-
CiteScore
5.70
自引率
14.80%
发文量
65
审稿时长
46 days
期刊介绍: Forensic Chemistry publishes high quality manuscripts focusing on the theory, research and application of any chemical science to forensic analysis. The scope of the journal includes fundamental advancements that result in a better understanding of the evidentiary significance derived from the physical and chemical analysis of materials. The scope of Forensic Chemistry will also include the application and or development of any molecular and atomic spectrochemical technique, electrochemical techniques, sensors, surface characterization techniques, mass spectrometry, nuclear magnetic resonance, chemometrics and statistics, and separation sciences (e.g. chromatography) that provide insight into the forensic analysis of materials. Evidential topics of interest to the journal include, but are not limited to, fingerprint analysis, drug analysis, ignitable liquid residue analysis, explosives detection and analysis, the characterization and comparison of trace evidence (glass, fibers, paints and polymers, tapes, soils and other materials), ink and paper analysis, gunshot residue analysis, synthetic pathways for drugs, toxicology and the analysis and chemistry associated with the components of fingermarks. The journal is particularly interested in receiving manuscripts that report advances in the forensic interpretation of chemical evidence. Technology Readiness Level: When submitting an article to Forensic Chemistry, all authors will be asked to self-assign a Technology Readiness Level (TRL) to their article. The purpose of the TRL system is to help readers understand the level of maturity of an idea or method, to help track the evolution of readiness of a given technique or method, and to help filter published articles by the expected ease of implementation in an operation setting within a crime lab.
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