Application of differential scanning calorimetry in hair samples as a possible tool in Forensic Science

A calorimetria Exploratória Diferencial (DSC) foi utilizada para estudar o comportamento térmico de amostras de cabelo e verificar a possibilidade de identificar um indivíduo com base nas curvas DSC de um banco de dados. Amostras de cabelo de estudantes e funcionários do Instituto de Química de Araraquara UNESP, foram obtidas para construir um banco de dados. Procurou-se assim identificar de um indivíduo sob incógnita, utilizando-se a curva DSC deste banco de dados.

The GHEP-EMPOP collaboration on mtDNA population data-A new resource for forensic casework

Mitochondrial DNA (mtDNA) population data for forensic purposes are still scarce for some populations, which may limit the evaluation of forensic evidence especially when the rarity of a haplotype needs to be determined in a database search. In order to improve the collection of mtDNA lineages from the Iberian and South American subcontinents, we here report the results of a collaborative study involving nine laboratories from the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) and EMPOP. The individual laboratories contributed population data that were generated throughout the past 10 years, but in the majority of cases have not been made available to the scientific community. A total of 1019 haplotypes from Iberia (Basque Country, 2 general Spanish populations, 2 North and 1 Central Portugal populations), and Latin America (3 populations from São Paulo) were collected, reviewed and harmonized according to defined EMPOP criteria. The majority of data ambiguities that were found during the reviewing process (41 in total) were transcription errors confirming that the documentation process is still the most error-prone stage in reporting mtDNA population data, especially when performed manually. This GHEP-EMPOP collaboration has significantly improved the quality of the individual mtDNA datasets and adds mtDNA population data as valuable resource to the EMPOP database (www.empop.org). (C) 2010 Elsevier B.V. All rights reserved.

Latin-American Society Of Forensic Genetics (SLAGF) results of the Interlaboratory Quality Control Exercise 2010-2011

Latin-American Society of Forensic Genetics (SLAGF) Interlaboratory Quality Control Exercise (2010-2011) included the analysis of three bloodstain samples in FTA Classic Card (three persons, biologically unrelated) and one theoretical exercise. There were 56 participating laboratories from 13 Latin-American countries that belong to society, were reported 70 STRs, including autosomal and sex chromosome markers with consensus in 53 STRs with a rate in reporting errors of 2.3%. Fifty-six laboratories reported results in theoretical exercise with mistakes in calculation of IP for each marker. It is necessary to hold meetings to discuss the results of this exercise to reach conclusions and recommendations on all aspects of DNA forensics analysis and paternity test, to improve results and quality in the results of each laboratory. © 2011 Elsevier B.V.

Is characterizing the digital forensic facial reconstruction with hair necessary? A familiar assessors' analysis

Background: In the international scientific literature, there are few studies that emphasize the presence or absence of hair in forensic facial reconstructions. There are neither Brazilian studies concerning digital facial reconstructions without hair, nor research comparing recognition tests between digital facial reconstructions with hair and without hair. The miscegenation of Brazilian people is considerable. Brazilian people, and, in particular, Brazilian women, even if considered as Caucasoid, may present the hair in very different ways: curly, wavy or straight, blonde, red, brown or black, long or short, etc. For this reason, it is difficult to find a correct type of hair for facial reconstruction (unless, in real cases, some hair is recovered with the skeletal remains). Aims and methods: This study focuses on the performance of three different digital forensic facial reconstructions, without hair, of a Brazilian female subject (based on one international database and two Brazilian databases for soft facial-tissue thickness) and evaluates the digital forensic facial reconstructions comparing them to photographs of the target individual and nine other subjects, employing the recognition method. A total of 22 assessors participated in the recognition process; all of them were familiar with the 10 individuals who composed the face pool. Results and conclusions: The target subject was correctly recognized by 41% of the 22 examiners in the International Pattern, by 32% in the Brazilian Magnetic Resonance Pattern and by 32% in the Brazilian Fresh Cadavers Pattern. The facial reconstructions without hair were correctly recognized using the three databases of facial soft-tissue thickness. The observed results were higher than the results obtained using facial reconstructions with hair, from the same skull, which can indicate that it is better to not use hair, at least when there is no information concerning its characteristics. © 2013 Elsevier B.V. All rights reserved.

Development and validation of a D-loop mtDNA SNP assay for the screening of specimens in forensic casework

Mitochondrial DNA (mtDNA) analysis is usually a last resort in routine forensic DNA casework. However, it has become a powerful tool for the analysis of highly degraded samples or samples containing too little or no nuclear DNA, such as old bones and hair shafts. The gold standard methodology still constitutes the direct sequencing of polymerase chain reaction (PCR) products or cloned amplicons from the HVS-1 and HVS-2 (hypervariable segment) control region segments. Identifications using mtDNA are time consuming, expensive and can be very complex, depending on the amount and nature of the material being tested. The main goal of this work is to develop a less labour-intensive and less expensive screening method for mtDNA analysis, in order to aid in the exclusion of non-matching samples and as a presumptive test prior to final confirmatory DNA sequencing. We have selected 14 highly discriminatory single nucleotide polymorphisms (SNPs) based on simulations performed by Salas and Amigo (2010) [1] to be typed using SNaPShotTM (Applied Biosystems, Foster City, CA, USA). The assay was validated by typing more than 100 HVS-1/HVS-2 sequenced samples. No differences were observed between the SNP typing and DNA sequencing when results were compared, with the exception of allelic dropouts observed in a few haplotypes. Haplotype diversity simulations were performed using 172 mtDNA sequences representative of the Brazilian population and a score of 0.9794 was obtained when the 14 SNPs were used, showing that the theoretical prediction approach for the selection of highly discriminatory SNPs suggested by Salas and Amigo (2010) [1] was confirmed in the population studied. As the main goal of the work is to develop a screening assay to skip the sequencing of all samples in a particular case, a pair-wise comparison of the sequences was done using the selected SNPs. When both HVS-1/HVS-2 SNPs were used for simulations, at least two differences were observed in 93.2% of the comparisons performed. The assay was validated with casework samples. Results show that the method is straightforward and can be used for exclusionary purposes, saving time and laboratory resources. The assay confirms the theoretic prediction suggested by Salas and Amigo (2010) [1]. All forensic advantages, such as high sensitivity and power of discrimination, as also the disadvantages, such as the occurrence of allele dropouts, are discussed throughout the article. © 2013 Elsevier B.V.

Dental fluorescence: Potential forensic use

In cases of identification of bones, skeletal segments or isolated bones, searching for biotypologic diagnostic data to estimate an individual's age enables comparing these data with those of missing individuals. Enamel, dentin and pulp undergo remarkable changes during an individual's life. The enamel becomes more mineralized, smoother and thinner, and deteriorates because of physiological and pathological factors. Dental pulp decreases in volume due to the deposition of secondary dentin; thus, the dentin becomes thicker with time. In natural teeth, the fluorescence phenomenon occurs in dentin and enamel and changes in those tissues may alter the expression of the natural tooth color. The aim of this study was to assess the correlation between age and teeth fluorescence for individuals from different age groups. The sample consisted of 66 randomly selected Brazilians of both genders aged 7-63 years old. They were divided into 6 groups: Group 1 - aged 7-12 years, Group 2 - aged 13-20 years, Group 3 - aged 21-30 years, Group 4 - aged 31-40 years, Group 5 - aged 41-50 years and Group 6 - aged between 51 and 63 years. Upper right or left central incisors were used for the study. Restored and aesthetic rehabilitated teeth were excluded from the sample. The measurement of tooth fluorescence was carried out via computer analysis of digital images using the software ScanWhite DMC/Darwin Systems - Brazil. It was observed that dental fluorescence decreases when comparing the age groups 21-30, 31-40, 41-50 and 51-63 years. The results also showed that there is a statistically significant difference between the groups 41-50 years and 21-30 years (p=. 0.005) and also among the group 51-63 years and all other groups (p< 0.005). It can be concluded that dental fluorescence is correlated with age and has a similar and stable behavior from 7 to 20 years of age. It reaches its maximum expected value at the age of 26.5 years and thereafter decreases. © 2013 Elsevier B.V.

Development of mev-eds methodology for forensic analysis on automotive headlights

A comparative study between three automotive headlights (conventional, halogen, and HID lamp) using scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS) is described. Results show the possibility of conducting topographic and qualitative analysis of automotive light bulbs from vehicles involved in traffic accidents on the basis of similarities between the waste glass material left on the filaments. This should provide evidence as to whether the bulbs were energized at the time of the accident.

Voltammetric determination of Δ 9-THC in glassy carbon electrode: an important contribution to forensic electroanalysis

A new voltammetric method for the determination of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) is described. The voltammetric experiments were accomplished in N-N dimethylformamide/water (9: 1, v/v), using tetrabutylammonium tetrafluoroborate (TBATFB) 0.1 mol/L as supporting electrolyte and a glassy carbon disk electrode as the working electrode. The anodic peak current was observed at 0.0 V (vs. Ag/AgCl) after a 30 s pre-concentration step under an applied potential of -1.2 V (vs. Ag/AgCl). A linear dependence of Delta(9)-THC detection was obtained in the concentration range 2.4-11.3 ng/mL, with a linear correlation coefficient of 0.999 and a detection limit of 0.34 ng/mL. The voltammetric method was used to measure the content of Delta(9)-THC in samples (hemp and hashish) confiscated by the police. The elimination of chemical interferences from the samples was promptly achieved through prior purification using the TLC technique, by employing methanol/water (4: 1, v/v) as the mobile phase. The results showed excellent correlation with results attained by HPLC.

Forensic electrochemistry: indirect electrochemical sensing of the components of the new psychoactive substance Synthacaine

Synthacaine is a New Psychoactive Substance which is, due to its inherent psychoactive properties, reported to imitate the effects of cocaine and is therefore consequently branded as legal cocaine. The only analytical approach reported to date for the sensing of Synthacaine is mass spectrometry. In this paper, we explore and evaluate a range of potential analytical techniques for its quantification and potential use in the field screening Synthacaine using Raman spectroscopy, presumptive (colour) testing, High Performance Liquid Chromatography (HPLC) and electrochemistry. HPLC analysis of street samples reveals that Synthacaine comprises a mixture of methiopropamine (MPA) and 2-aminoindane (2-AI). Raman spectroscopy and presumptive (colour) tests, the Marquis, Mandelin, Simon's and Robadope test, are evaluated towards a potential in-the-field screening approach but are found to not be able to discriminate between the two when they are both present in the same sample, as is the case in the real street samples. We report for the first time a novel indirect electrochemical protocol for the sensing of MPA and 2-AI which is independently validated in street samples with HPLC. This novel electrochemical approach based upon one-shot disposable cost effective screen-printed graphite macroelectrodes holds potential for in-the-field screening for Synthacaine.

Book Review of Entomology at the Land Grant University: Perspectives from the Texas A&M University Department Centenary Edited by Kevin M. Heinz, Raymond Frisbie, and Carlos Bogran

This book offers the texts of twenty-four presentations given in a series of mini symposia organized to commemorate the centennial of Texas A&M's Department of Entomology. Although not stated explicitly by the editors, the central theme for these symposia seems to be the contributions of the discipline of entomology to modern society. The presentations cover a wide range of topics dealing with the importance of insects in both natural ecosystems and agricultural systems; insects as models for scientific research; challenges associated with effective management of those species that are pests in systems designed for food and fiber production; and the role of entomology departments within academic institutions, particularly land-grant universities. The list of contributors to these symposia is impressive, as are the universities and other institutions they represent across the United States as well as in Europe and Africa.

A forensic study: Lead determination in gunshot residues

Electrochemical lead analyses of gunshot residues (GSRs) were performed using an acidic solution with a bare gold microelectrode in the presence of chloride ions. GSRs from four different guns (0.38 in. revolver, 12 caliber pump-action shotgun, 0.38 repeating rifle, and a 0.22 caliber semi-automatic rifle) and six different types of ammunition (CleanRange (R), normal, semi-jacketed, especial 24g (R), 3T (R), CBC (R), and Eley (R)) were analyzed. Results obtained with the proposed methodology were compared with those from an atomic absorption spectrometry analysis, and a paired Student's t-test indicated that there was no significant difference between them at the 95% confidence level. With this methodology, a detection limit of 1.7 nmol L-1 (3 sigma/slope), a linear range between 10 and 100 nmol L-1, and a relative standard deviation of 2.5% from 10 measurements were obtained. (C) 2011 Elsevier B.V. All rights reserved.

Pharmacogenetics and forensic toxicology

Large inter-individual variability in drug response and toxicity, as well as in drug concentrations after application of the same dosage, can be of genetic, physiological, pathophysiological, or environmental origin. Absorption, distribution and metabolism of a drug and interactions with its target often are determined by genetic differences. Pharmacokinetic and pharmacodynamic variations can appear at the level of drug metabolizing enzymes (e.g., the cytochrome P450 system), drug transporters, drug targets or other biomarker genes. Pharmacogenetics or toxicogenetics can therefore be relevant in forensic toxicology. This review presents relevant aspects together with some examples from daily routines.

[Analysis of clinical forensic examination reports on sexually abused children]

Clinical forensic examinations of children suspected of having been sexually abused are increasingly part of the routine of medicolegal institutes. The findings collected from 2005 until 2007 at the Institute of Legal Medicine of the Hanover Medical School were analysed retrospectively. Altogether, 91 children (74 females, 17 males, mean age 8.7 years) were examined. In 87.9% of the cases, the examination had been ordered by the police. In 73.6%, the victim knew the suspected perpetrator well or he was a family member. 40.7% of the children were seen within 72 hours after the alleged abuse. 12.1% of the children had extragenital lesions. In 27% of the victims, marked anogenital injuries were found, which were characteristic of sexual abuse in 9%. In 18 cases (20.2%), swabs were taken for spermatozoa detection. 3 of 17 vaginal smears showed positive test results for sperm up to 21 hours after the incident. No spermatozoa could be detected in 4 anal and 2 oral swabs as well as in one swab taken from the skin of the victim's thigh. In summary, the evaluation shows that early clinical forensic examination of children suspected of having been sexually abused is crucial to document evidence that is highly significant for the investigation and court proceedings. Often suspected sexual child abuse cannot be proved by medical findings alone. Of course, the absence of anogenital injuries does nor rule out sexual abuse.