A novel approach using ATR-FTIR spectroscopy and chemometric analysis to distinguish male and female human hair samples.

This article presents an attempt to discriminate between human male and female hair samples using a single strand of scalp hair. The methodology involves the non-destructive application of ATR-FTIR spectroscopy coupled with chemometric analysis. A total of 96 hair samples, evenly distributed between 48 male and 48 female volunteers from India, were collected. Spectral analysis revealed subtle differences between the two groups, and reliance on visual interpretation might introduce biasness. To avoid subjective biases, chemometric techniques such as principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were employed for enhanced data visualization and separation. PCA results revealed that the first 10 principal components accounted for 93% of the total variance, with three significant PCs. The PLS-DA model demonstrated a remarkable sensitivity and specificity in sex discrimination from hair samples, establishing its efficacy as a robust classification tool. Furthermore, the proposed model exhibited 100% accuracy in predicting unknown samples, underscoring its potential applicability in real-world scenarios. These outcomes affirm the viability of our approach for non-invasive classification of human male and female hair based on single-strand scalp hair analysis.

Applications of MALDI mass spectrometry in forensic science.

Forensic chemistry literature has grown exponentially, with many analytical techniques being used to provide valuable information to help solve criminal cases. Among them, matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), particularly MALDI MS imaging (MALDI MSI), has shown much potential in forensic applications. Due to its high specificity, MALDI MSI can analyze a wide variety of compounds in complex samples without extensive sample preparation, providing chemical profiles and spatial distributions of given analyte(s). This review introduces MALDI MS(I) to forensic scientists with a focus on its basic principles and the applications of MALDI MS(I) to the analysis of fingerprints, drugs of abuse, and their metabolites in hair, medicine samples, animal tissues, and inks in documents.

Forensic Characterization, Genomic Variability and Ancestry Analysis of Six Populations from Odisha Using mtDNA SNPs and Autosomal STRs.

Located on India's eastern coast, Odisha is known for its diverse tribes and castes. In the early days of genome sequencing technology, researchers primarily studied the Austroasiatic communities inhabiting this region to reconstruct the ancient origins and dispersal of this broad linguistic group. However, current research has shifted towards identifying population and individual-specific genome variation for forensic applications. This study aims to analyze the forensic efficiency and ancestry of six populations from Odisha. We assessed the SF mtDNA-SNP60™ PCR Amplification Kit by comparing it with PowerPlex® Fusion 6C System, a widely used autosomal STR (aSTR) kit, in an Indian cohort. Although the mtDNA SNP kit showed low discriminating power for individuals of a diverse population, it could identify deep lineage divergence. Also, we utilized mitochondrial and autosomal variation information to analyze the ancestry of six endogamous ethnic groups in Odisha. We observe two extremities-populations with higher West Asian affinity and those with East Asian affinity. This observation is in congruence with the existing information of their tribal and non-tribal affiliation. When compared with neighbouring populations from Central and Eastern India, multivariate analysis showed that the Brahmins clustered separately or with the Gopala, Kaibarta appeared as an intermediate, Pana and Kandha clustered with the Gonds, and Savara with the Munda tribes. Our findings indicate significant deep lineage stratification in the ethnic populations of Odisha and a gene flow from West and East Asia. The artefacts of unique deep lineage in such a diverse population will help in improving forensic identification. In addition, we conclude that the SF mtDNA-SNP60 PCR Amplification Kit may be used only as a supplementary tool for forensic analysis.

Fingerprint Recognition in Forensic Scenarios.

Fingerprints are unique patterns used as biometric keys because they allow an individual to be unambiguously identified, making their application in the forensic field a common practice. The design of a system that can match the details of different images is still an open problem, especially when applied to large databases or, to real-time applications in forensic scenarios using mobile devices. Fingerprints collected at a crime scene are often manually processed to find those that are relevant to solving the crime. This work proposes an efficient methodology that can be applied in real time to reduce the manual work in crime scene investigations that consumes time and human resources. The proposed methodology includes four steps: (i) image pre-processing using oriented Gabor filters; (ii) the extraction of minutiae using a variant of the Crossing Numbers method which include a novel ROI definition through convex hull and erosion followed by replacing two or more very close minutiae with an average minutiae; (iii) the creation of a model that represents each minutia through the characteristics of a set of polygons including neighboring minutiae; (iv) the individual search of a match for each minutia in different images using metrics on the absolute and relative errors. While in the literature most methodologies look to validate the entire fingerprint model, connecting the minutiae or using minutiae triplets, we validate each minutia individually using n-vertex polygons whose vertices are neighbor minutiae that surround the reference. Our method also reveals robustness against false minutiae since several polygons are used to represent the same minutia, there is a possibility that even if there are false minutia, the true polygon is present and identified; in addition, our method is immune to rotations and translations. The results show that the proposed methodology can be applied in real time in standard hardware implementation, with images of arbitrary orientations.

Forensic significance of VOCs profiling in decayed ante- and post-mortem injuries by GC×GC-TOF/MS.

Accurately identifying and differentiating the types of injuries in decomposed corpses is a major challenge in forensic identification. Forensic investigations involving decomposed cadavers pose challenges in determining the cause of death. Traditional methods often lack conclusive evidence. However, the implementation of advanced analytical techniques, such as comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOF/MS), shows promise in overcoming these limitations, but the potential in this area remains limited. Therefore, this study aims to bridge this gap by exploring the potential of GC × GC-TOF/MS in the analysis of volatile organic compounds (VOCs) changes within decaying ante- and post-mortem injuries.The research emphasizes the forensic significance of VOCs changes in decomposed cadavers. We used GC × GC-TOF/MS analysis to identify the specific volatile compounds in putrefied corpse tissue samples from mice. The GC × GC-TOF/MS analysis results showed that under winter conditions, PC1 explained 57.16% of the variance, and PC2 explained 25.23% of the variance; while under summer conditions, PC1 explained 71.89% of the variance, and PC2 explained 24.49% of the variance. This demonstrates the potential of GC × GC-TOF/MS in identifying specific VOCs present in tissue samples that can serve as potential biomarkers for distinguishing between antemortem and postmortem injury. GC × GC-TOF/MS analysis revealed distinct VOC patterns in both conditions. Comprehensive use of GC × GC-TOF/MS analysis enhances accuracy in identifying and characterizing ante- and post-mortem injuries in decomposed cadavers. This study can significantly contribute to the field of forensic medicine and improve the accuracy of forensic investigations.

Impact on touch DNA of an alcohol-based hand sanitizer used in COVID-19 prevention.

In the last years, forensic research has been focused on touch DNA in order to improve its evidential value in criminal activity investigations as well as to understand the variables impacting touch DNA. One of the emerging variables is represented by the use of alcohol-based sanitizers, which was suggested for hand hygiene during the COVID-19 pandemic. The aims of the present study were to assess the effect of a hand sanitizer on touch DNA deposition, transfer, and recovery and also to evaluate STR typing success, quality of DNA profiles, and personal identification. Before and after the use of an alcohol-based hand sanitizer, 20 volunteers deposited on glass surfaces 120 fingerprints, containing skin-derived or salivary DNA. Samples were quantified by real-time quantitative PCR (q-PCR), and 76 samples yielding > 15 pg/µl were typed for 21 autosomal STRs by GlobalFiler® PCR Amplification Kit. DNA profiles were classified into single source, mixed, and inconclusive profiles, and a LR assessment was performed by comparison to the reference samples using LRmix Studio software. After the use of hand sanitizer, samples yielded lower quantities of recovered transferred DNA, especially considering samples containing salivary DNA (p < 0.05 by Friedman test). All the 76 amplified samples (63.3% of the total) showed at least 10 typed loci, and 83-100% of profiles were consistent with the reference ones on the basis of a LR value ≥ 106. Results showed that, although the hand sanitizer reduces the DNA recovering, touch DNA samples might still be useful for forensic personal identification even when hand sanitizers are used.

Concurrent determination of cyanide and thiocyanate in human and swine antemortem and postmortem blood by high-performance liquid chromatography-tandem mass spectrometry.

Cyanide (in the form of cyanide anion (CN-) or hydrogen cyanide (HCN), inclusively represented as CN) can be a rapidly acting and deadly poison, but it is also a common chemical component of a variety of natural and anthropogenic substances. The main mechanism of acute CN toxicity is based on blocking terminal electron transfer by inhibiting cytochrome c oxidase, resulting in cellular hypoxia, cytotoxic anoxia, and potential death. Due to the well-established link between blood CN concentrations and the manifestation of symptoms, the determination of blood concentration of CN, along with the major metabolite, thiocyanate (SCN-), is critical. Because currently there is no method of analysis available for the simultaneous detection of CN and SCN- from blood, a sensitive method for the simultaneous analysis of CN and SCN- from human ante- and postmortem blood via liquid chromatography-tandem MS analysis was developed. For this method, sample preparation for CN involved active microdiffusion with subsequent chemical modification using naphthalene-2,3-dicarboxaldehyde (NDA) and taurine (i.e., the capture solution). Preparation for SCN- was accomplished via protein precipitation and monobromobimane (MBB) modification. The method produced good sensitivity for CN with antemortem limit of detection (LODs) of 219 nM and 605 nM for CN and SCN-, respectively, and postmortem LODs of 352 nM and 509 nM. The dynamic ranges of the method were 5-500 µM and 10-500 µM in ante- and postmortem blood, respectively. In addition, the method produced good accuracy (100 ± 15%) and precision (≤ 15.2% relative standard deviation). The method was able to detect elevated levels of CN and SCN- in both antemortem (N = 5) and postmortem (N = 4) blood samples from CN-exposed swine compared to nonexposed swine.

Introducing protein deamidation: Landmark discoveries, societal outreach, and tentative priming workflow to address deamidation.

Our current knowledge on protein deamidation results from a journey that started almost 100 years ago, when a handful of researchers first described the non-enzymatic "desamidation" of glutamine, and the effect of different anions on the catalytic rate of the reaction. Since then, the field has tremendously expended and now finds outreach in very diverse areas. In light of all the recent articles published in these areas, it seemed timely to propose an integrated review on the subject, including a short historical overview of the landmark discoveries in the field, highlighting the current global positioning of protein deamidation in biology and non-biology fields, and concluding with a workflow for those asking if a protein can deamidate, and identify the residues involved. This review is essentially intended to provide newcomers in the field with an overview of how deamidation has penetrated our society and what tools are currently at hand to identify and quantify protein deamidation.

Non-psychoactive cannabinoids identification by linear retention index approach applied to a hand-portable capillary liquid chromatography platform.

The aim of the present research was the application of the linear retention index (LRI) system for the identification of non-psychoactive cannabinoids using a portable LC instrument. The miniaturization, viz. the use of very low quantities of mobile phase, enabled the development of a compact mobile system to be used for in situ analysis, also according to a green and cost-saving approach. In particular, new capillary LC (cap-LC) methods coupled with UV detection were developed for the analysis of extracts of Cannabis sativa L. Two setups were explored to achieve the efficient separation of twenty-four cannabinoids: a single column setup which exploited a sub-2 µm packing to increase the chromatographic resolution, and a dual-column setup based on the serial connection of two different stationary phases, each coupled to an UV detector. The latter allowed the determination of two LRI values for each analyte, thus increasing the identification power. Moreover, since two different wavelengths were used on the LED-based UV detectors, the ratio of the absorbances measured on each chromatographic trace represented a third identification criterion, thus fulfilling the recommendations of the Scientific Working Group for The Analysis of Seized Drugs (SWDRUG) about the categories of analytical techniques to be used and the minimum number of parameters required for the unambiguous identification of drugs. The obtained results could be used for the development of a novel analytical method for fast and automatic in situ forensic investigations and hemp breeding programs, also minimizing the consumption of both sample and solvent.

Use of micro, capillary, and nano liquid chromatography for forensic analysis.

The use of micro, capillary, and nano liquid chromatography systems for forensic analysis has excellent potential. In a field where sample size is often limited, several studies have presented the viability of capillary columns with microflow and nanoflow, and when using mass spectrometric analysis limits of detection can be improved. Reduction in flow rates result in significant reduction in operating costs. Recent advances in miniaturized liquid chromatography systems also aim at in-laboratory and on-site detection, which have already been applied to forensic drug cases. This critical review will discuss the advantages, disadvantages, and applicability of microflow and nano liquid chromatography. In this regard, included in this article is a discussion of some promising areas not yet applied to forensic research.