Development and validation of a next generation STR ESS-pentaplex

We constructed a simple STR pentaplex of new loci recommended as next generation markers for the European Standard Set (ESS) comprising normal-amplicon STRs: D12S391 and D1S1656, plus mini-amplicon STRs: D2S441, D10S1248 and D22S1045. Validation of the pentaplex included evaluation of its ability to amplify DNA from a variety of degraded forensic casework samples. Although the ESS-pentaplex was designed in the first instance to generate allele frequency data to supplement existing databases of established STRs, the multiplex proved to be a valuable tool for the analysis of challenging DNA when certain markers of Identifiler or MiniFiler occasionally failed.     

Variability of the Entire Mitochondrial DNA Control Region in a Human Isolate from the Pas Valley (Northern Spain)

Abstract: In this study, we analyzed the entire mtDNA control region in 61 unrelated individuals from the Pas Valley (Cantabria), a human isolate from northern Spain, to evaluate the suitability of this analysis to increase the power of discrimination of this locus for forensic purposes in human isolates. Low values obtained for the diversity parameters confirmed the relative isolation of this human group. The main findings of this study indicated that even the analysis of the entire mtDNA control region may have important limitations for use in forensic casework when dealing with human isolates: none of the 44 individuals who exhibited identical HVI‐HVII haplotypes could be further differentiated by analysis of segment HVIII. Nevertheless, analysis of the entire mtDNA control region proved to be useful to determine the ancestry of the samples examined, by contributing to the confirmation, and, on occasion, even to the refinement of the haplogroup assignment.     

Color Stability of Dental Restorative Materials Submitted to Heat Sources,for Forensic Purposes

During postmortem examination of the dental arches of carbonized victims, dental restorative materials may be found. The aim of this study was to evaluate the effect of heat source action on the color stability of composite resin (CR) and glass ionomer cement (GIC) restorations, to discriminate between them and compare with antemortem dental data. Sixty bovine teeth (30 CR and 30 GIC) were prepared (6 × 6 × 2 mm) and separated into groups (n = 10). The color readouts were taken by spectrophotometer, before and after heat action (100°C, 200°C, 300°C), in an oven for 15 min. There were color alterations for all coordinates (ΔE, ΔL*, Δa* eΔb*) for both materials. GIC presented greater change. The authors concluded that it is possible to distinguish between the materials by the color changes analyzed by instrumental method, helping victim identification.     

Bayesian framework for the evaluation of fiber evidence in a double murder--a case report

Fiber evidence found on a suspect vehicle was the only useful trace to reconstruct the dynamics of the transportation of two corpses. Optical microscopy, UV-Vis microspectrophotometry and infrared analysis were employed to compare fibers recovered in the trunk of a car to those of the blankets composing the wrapping in which the victims had been hidden. A "pseudo-1:1" taping permitted to reconstruct the spatial distribution of the traces and to further strengthen the support to one of the hypotheses. The Likelihood Ratio (LR) was calculated, in order to quantify the support given by forensic evidence to the explanations proposed. A generalization of the Likelihood Ratio equation to cases analogous to this has been derived. Fibers were the only traces that helped in the corroboration of the crime scenario, being absent any DNA, fingerprints and ballistic evidence.     

Quantitative analysis of multiple illicit drugs in preserved oral fluid by solid-phase extraction and liquid chromatography–tandem mass spectrometry

We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC–MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept^®, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC–MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2–200 μg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 μg/L. Limits of quantitation were estimated to be at 2 μg/L with limits of detection ranging from 0.2 to 0.5 μg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept^® samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study.     

Intellectual property strategies for US security and privacy

Legal context. Some state legislatures are considering billswhich would require those applying for a driver’s licenceto provide one or more biometric identifiers. The US federalgovernment is tending towards eavesdropping on conversationsand investing in data mining efforts while on the other handanti "big-brother" technologies are also emerging to counterthis trend and protect privacy. The demand for technology toprotect privacy will no doubt increase as the demand for defenceand security spending increases. We also live in a world wherebioterrorist acts are a constant threat and therefore demandfor biological detection devices and nanotechnology is growingdaily. Key points. Current technology advances in biometrics, surveillance,biological detection and nanotechnology can be used both toprotect and to jeopardize the security and privacy of individuals.As such, the importance of intellectual property in these areascannot be underestimated. Practical significance. Companies are advised to ‘go onthe offensive’. All companies should aggressively protecttheir core technology in numerous facets such as patent protection,copyright, trade marks and trade secrets. In the high tech arenathis is especially important because the demand for securityand privacy necessitates the development of advanced applicationsand in turn the quality of protectable IP for the companiesthat develop the technology increases. Additionally, companiesshould also pursue an offensive strategy that includes analyzingemerging standards and competitor focus so that they can acquirea competitive advantage or secure cross-licensing of another’stechnology.     

Correlation of Delta9-tetrahydrocannabinol concentrations determined by LC-MS-MS in oral fluid and plasma from impaired drivers and evaluation of the on-site Dräger DrugTest

Oral fluid (collected with the Intercept((R)) device) and plasma samples were obtained from 139 individuals suspected of driving under the influence of drugs and analyzed for Delta(9)-tetrahydrocannabinol (THC), the major psychoactive constituent of cannabis, using a validated quantitative LC-MS-MS method. The first aim of the study was to investigate the correlation between the analytical data obtained in the plasma and oral fluid samples, to evaluate the use of oral fluid as a 'predictor' of actual cannabis influence. The results of the study indicated a good accuracy when comparing THC detection in oral fluid and plasma (84.9-95.7% depending on the cut-off used for plasma analysis). ROC curve analysis was subsequently used to determine the optimal cut-off value for THC in oral fluid with plasma as reference sample, in order to 'predict' a positive plasma result for THC. When using the LOQ of the method for plasma (0.5 ng/mL), the optimal cut-off was 1.2 ng/mL THC in oral fluid (sensitivity, 94.7%; specificity, 92.0%). When using the legal cut-off in Belgium for driving under the influence in plasma (2 ng/mL), an optimal cut-off value of 5.2 ng/mL THC in oral fluid (sensitivity, 91.6%; specificity, 88.6%) was observed. In the second part of the study, the performance of the on-site Dr?ger DrugTest for the screening of THC in oral fluid during roadside controls was assessed by comparison with the corresponding LC-MS-MS results in plasma and oral fluid. Since the accuracy was always less than 66%, we do not recommend this Dr?ger DrugTest system for the on-site screening of THC in oral fluid.     

A quantitative differentiation method for acrylic fibers by infrared spectroscopy

Absorbance peak areas of nitrile (2240 cm(-1)), carbonyl (1730 cm(-1)) and CH (1370 cm(-1)) groups were obtained for 48 colorless acrylic fibers by infrared (IR) microspectroscopy. The carbonyl signal, related to the comonomers most commonly used in acrylic fibers, was ratioed against the nitrile and CH bands, pertaining to the backbone of the polymer chains. The ratios A1730/A2240 and A1730/A1370, a relative measure of the comonomer content in the fiber, were used to differentiate the samples. A decrease in the crystallinity of fibers has been noted with increasing comonomer content. Relative standard deviation (R.S.D.) of the ratios were 1 and 3% for repetitive analyses on the same location and along the length of the same single fiber, respectively. When different fibers of the same sample were examined, results were reproducible within 6%. This simple method can greatly enhance the evidential value of colorless acrylic fibers, being able to discriminate them and thus helping the Court to better assess their significance.