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In this work, a selection of the best features for multivariate forensic glass classification using Scanning Electron Microscopy coupled with an Energy Dispersive X-ray spectrometer (SEM-EDX) has been performed. This has been motivated by the fact that the databases available for forensic glass classification are sparse nowadays, and the acquisition of SEM-EDX data is both costly and time-consuming for forensic laboratories. The database used for this work consists of 278 glass objects for which 7 variables, based on their elemental compositions obtained with SEM-EDX, are available. Two categories are considered for the classification task, namely containers and car/building windows, both of them typical in forensic casework. A multivariate model is proposed for the computation of the likelihood ratios. The feature selection process is carried out by means of an exhaustive search, with an Empirical Cross-Entropy (ECE) objective function. The ECE metric takes into account not only the discriminating power of the model in use, but also its calibration, which indicates whether or not the likelihood ratios are interpretable in a probabilistic way. Thus, the proposed model is applied to all the 63 possible univariate, bivariate and trivariate combinations taken from the 7 variables in the database, and its performance is ranked by its ECE. Results show remarkable accuracy of the best variables selected following the proposed procedure for the task of classifying glass fragments into windows (from cars or buildings) or containers, obtaining high (almost perfect) discriminating power and good calibration. This allows the proposed models to be used in casework. We also present an in-depth analysis which reveals the benefits of the proposed ECE metric as an assessment tool for classification models based on likelihood ratios. © 2011 Elsevier B.V.

Zuba D.,Institute of Forensic Research | Byrska B.,Institute of Forensic Research
Forensic Toxicology | Year: 2013

"Herbal highs" are a group of products marketed in recent years as legal substitutes for marijuana. This article presents the results of examinations performed on samples seized in "head shops" and from individuals during a 3.5-year period, between mid-2008 and the end of 2011 in Poland. Of over 2000 samples delivered for analysis, 420 preparations were selected for this study. Gas chromatography-mass spectrometry and liquid chromatography-quadrupole-time-of-flight-mass spectrometry were used for identification of psychoactive components, and high-performance liquid chromatography was used for their quantitation. The most common ingredients of herbal highs were: JWH-081 (144 products), JWH-018 (103), RCS-4 (92), JWH-073 (89), JWH-250 (75), JWH-122 (69), cannabicyclohexanol (55), and JWH-210 (38). Over 50 % of the products contained two or more active ingredients; 136 products (32.4 %) contained two; 56 products (13.3 %) contained three; and 22 (5.2 %) contained more than three. Common combinations of ingredients were investigated by the graph method; substances coexisted mainly with those introduced into the drug market in a similar period of time. The most common dual combinations were JWH-081 + RCS-4 (18 products), JWH-073 + JWH-250 (16), and JWH-081 + JWH-250 (12). JWH-081 was blended with almost all detected synthetic cannabinoids. The main risks of the use of these substances were due to ignorance of great variation in the content and composition of synthetic cannabinoids even if the products had identical labels. This inconsistency could cause serious health damage to users, while ignorance of the fact that more than one third of the products being sold at head shops contain illicit compound(s) could result in unexpected arrest. © 2012 Japanese Association of Forensic Toxicology and Springer.

Wach W.,Institute of Forensic Research
SAE Technical Papers | Year: 2013

Critical Speed Formula (CSF) belongs to the canon of tools used in reconstruction of vehicle accidents. It is used to calculate vehicle speed at the beginning of tire yaw marks and, together with the entire methodology of processing the information contained in the marks into the data, is often referred to as the Critical Speed Method (CSM). Its great practical importance as well as recurring doubts as to the reliability make it one of the best experimentally and theoretically studied methods. Although the CSF applies in fact to a point mass, it is used with reference to a vehicle, i.e. an increasingly complicated multi-body system. Accident reconstruction experts point out the particular usefulness of Lambourn's research concerning the CSM in respect to a passenger car. Because his method by virtue of solid research basis is extensively applied in practice, the paper is focused specifically on Lambourn's methodology in terms of analysis of uncertainty and influence of vehicle properties. Regarding the first problem, sensitivity and uncertainty due to the parameters of the CSM was analyzed. Regarding the latter one, simulation tests using programs of different degrees of complexity were performed, taking into account criteria which were not considered in experimental tests. It has also been shown that in the case of unknown braking deceleration and large curvature of yaw mark, it will be desirable to shorten the chord c during the measurement and adjust the m/c (where m denotes the middle coordinate) ratio to the range from 0.01 to 0.03. This will ensure the reduction of calculation uncertainty to a level not exceeding ±10%, regardless of the torques applied to the wheels. The article presents the theoretical arguments supporting and extending Lambourn's thesis concerning error no greater than ± 10%, subject to the guidelines prescribed by Lambourn. Copyright © 2013 SAE International.

Czerederecka A.,Institute of Forensic Research
Z Zagadnien Nauk Sadowych | Year: 2013

Expert opinion is admissible as evidence in court and is therefore subject to evaluation. The question that immediately follows, however, is that of how and to what extent a court can control and evaluate the information provided by experts, whose knowledge is, by its very nature, specialised. The law lays down only general, formal requirements for expert opinions (Art. 200 and Art. 201 of the Code of Criminal Procedure and art. 285 § 1 of the Code of Civil Procedure) and, though methodological guidelines are given in a little more detail in the specialist legal literature, it would nevertheless appear essential to also consult the literature of the branches of learning the particular experts represent. In this way the specific nature of the data gathering, and of the grounds upon which the conclusions are drawn, can be taken into account. The aim of this article is to systematise the evaluation criteria for expert psychological opinions. It will first consider the American courts, where the evaluation criteria are distinguished by their orderliness and have a long tradition: the Frye standard of 1923, the Federal rules on the Admissibility of evidence of 1976 and the daubert standard of 1993. American forensic psychology takes into consideration guidelines specific to the conditions of the experts' work, which emphasise the specific nature of the interpersonal relationships involved and the ethical problems they entail: the Heilbrun model of 1992 and the Marlowe model of 1995. Polish court procedure does not yet possess such an homogenous system of evaluation and - considering the differences in legal systems and cultural conditioning - consideration is required in deciding which of the American experiences can be applied in Poland. The article then presents guidelines for the evaluation of expert evidence as they are found in the Polish legal literature (Tomaszewski, Widła, Wójcikiewicz), as well as ten psychological criteria formulated by the author in 2005 based on the methodological and ethical requirements obligatory in psychological research and on the guidelines found in the forensic psychology literature. These may serve as a starting point in the systematisation of expert psychological opinion in court and, therefore, be of use both to the agencies that request such opinions and to the experts who prepare them. © by the Institute of Forensic Research.

Zuba D.,Institute of Forensic Research
TrAC - Trends in Analytical Chemistry | Year: 2012

The supply of psychoactive substances has changed and users increasingly buy " legal highs" over the Internet or in specialized shops. Vast arrays of preparations are marketed as legal substitutes to controlled substances. Their analysis has revealed that the majority of active components belong to one of four chemical classes: phenethylamines, tryptamines, piperazines and cathinones, the last being novel.This article gives special attention to cathinone derivatives and certain characteristic fragmentations based on the GC-EI/MS and LC-ESI/QTOF-MS spectra. The parent ions of these substances are hard to obtain by EI/MS, whereas the protonated molecular ions can be observed clearly by ESI/QTOF-MS. Furthermore, two major characteristic α-cleavages are produced when the EI mode is used, leading to formation of iminium and acylium ions, respectively. These ions can process secondary and tertiary fragmentations, which are very useful in identification. In the case of ESI/QTOF-MS, characteristic fragments are produced via loss of water in cathinones, being secondary amines.The targeted MS/MS mode allows us to identify structures of many unknown substances with certainty. Nevertheless, in order to determine the location of a substituent in a molecule, it is sometimes necessary to use NMR or FTIR.Problems found in identifying novel recreational drugs sold as " legal highs" indicate the need for international collaboration and sharing knowledge and analytical data amongst experts from forensic and clinical laboratories. © 2011 Elsevier Ltd.

Zuba D.,Institute of Forensic Research | Sekula K.,Institute of Forensic Research
Drug Testing and Analysis | Year: 2013

This publication reports analytical properties of three new hallucinogenic substances identified in blotter papers seized from the drug market, namely 25D-NBOMe [2-(2,5-dimethoxy-4-methylphenyl)-N-(2-methoxybenzyl)ethanamine], 25E-NBOMe [2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine] and 25G-NBOMe [2-(2,5-dimethoxy-3,4-dimethylphenyl)-N-(2-methoxybenzyl)ethanamine]. These substances are N-(2-methoxy)benzyl derivatives of the 2C-series of phenethylamine drugs. The applied procedure covered a variety of analytical methods, including gas chromatography with electron impact mass spectrometry (GC-EI-MS; without derivatization and after derivatization with trifluoroacetic anhydride (TFAA)), liquid chromatography-electrospray ionization-quadrupole time of flight mass spectrometry (LC-ESI-QTOF-MS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR), which made it possible to identify the active components unequivocally. The GC-MS spectra of analyzed compounds were very similar, with dominant ions observed at m/z=150, 121, and 91. The remaining ions were analogous to those observed for parent substances, namely 2C-D, 2C-E, 2C-G, but their intensities were low. Derivatization allowed determination of molecular masses of the investigated substances. Their exact masses and chemical formulas were confirmed by LC-QTOF-MS experiments and the fragmentation patterns of these compounds following ESI were determined. The tandem mass spectrometry (MS/MS) experiments confirmed that the studied substances were N-(2-methoxy)benzyl derivatives of the 2C-series compounds. Final elucidation of the structures was performed by NMR spectroscopy. The substances were also characterized by FTIR spectroscopy to corroborate the identity of the compounds. Copyright © 2012 John Wiley & Sons, Ltd. This publication reports the MS, IR and NMR spectroscopic data of three new hallucinogenic substances identified in blotter papers seized from the drug market, namely 25D-NBOMe [2-(2,5-dimethoxy-4-methylphenyl)-N-(2-methoxybenzyl)ethanamine], 25E-NBOMe [2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine] and 25G-NBOMe [2-(2,5-dimethoxy-3,4-dimethyl-phenyl)-N-(2-methoxybenzyl)ethanamine]. These substances are highly potent agonists of serotonin receptors (5-HT2A), with active doses at microgram levels. © 2012 John Wiley & Sons, Ltd..

Zieba-Palus J.,Institute of Forensic Research | Michalska A.,Institute of Forensic Research
Journal of Forensic Sciences | Year: 2014

Micro-Raman spectroscopy was applied to forensic identification of pigments in paint chips and provided differentiation between paint samples. Sixty-six blue automotive paint samples, 26 solid and 40 metallic were examined. It was found that the majority of the collected Raman spectra provided information about the pigments present. However, in some cases, fluorescence precluded pigment identification. Using laser excitation at longer wavelengths or pretreatment to effect photobleaching often resulted in reduced fluorescence, particularly for solid color samples, and allowed pigment identification. The examined samples were compared pairwise taking into account number, location, and intensity of absorption bands in their infrared spectra. The estimated discrimination power ranged from 97% for solid paint samples to 99% for metallic paint samples. © 2014 American Academy of Forensic Sciences.

Wach W.,Institute of Forensic Research
Forensic Science International | Year: 2013

Reconstruction of road accidents combines objective and subjective action. The former concerns science, the latter assessment of human behavior in the context of objective findings. It is not uncommon for experts equipped with an arsenal of tools to obtain similar results of calculations, but to present radically different conclusions about the cause of the accident. The use of sophisticated methods of uncertainty analysis does not guarantee improvement in quality of reconstruction, because, increasingly, the most serious source of reduced reliability of reconstruction is problems in logical inference. In the article the structure of uncertainty and reliability of accident reconstruction was described. A definition of reliability of road accident reconstruction based on the theory of conditional probability and Bayesian network, as a function of modeling, data and expert reliability (defined in the text) was proposed. The uncertainty of reconstruction was made dependent only on the uncertainty of the data. This separation makes it possible to conduct a qualitative and quantitative analysis of reconstruction reliability and to analyze its sensitivity to component parameters, independently of the uncertainty analysis. An example of calculation was presented. The proposed formalism constitutes a tool helpful to explain, among other things, the paradox of reliable reconstruction despite its uncertain results or unreliable reconstruction despite high precision of results. This approach is of great importance in the reconstruction of road accidents, which goes far beyond the analysis of a single, homogeneous subsystem. © 2013 Elsevier Ireland Ltd.

Zuba D.,Institute of Forensic Research | Byrska B.,Institute of Forensic Research
Drug Testing and Analysis | Year: 2013

The results of a study performed on samples of 'legal highs' seized in head shops by law enforcement and health services in Poland between mid-2008 and mid-2011 are presented. In total, 449 preparations which differed in labelling, net masses, forms of distribution, etc., were analyzed. A variety of sophisticated analytical methods, including gas chromatography-mass spectrometry (GC-MS), liquid chromatography-quadropole time-of-flight mass spectrometry (LC-QTOF-MS), high performance liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) were applied for component identification and quantification. The most common ingredients of legal highs were (in descending order): MPDV, caffeine, butylone, TFMPP, lidocaine, 4-MEC, mephedrone, pFPP, BZP, and MDPBP. The scatter of substances changed over time, and piperazines were often ousted by cathinones. Most of the preparations were composed of two or more ingredients. Cathinones and piperazines were mixed mainly within the chemical classes (77.6% and 56.1% of dual links, respectively), caffeine was mixed both with piperazines (24 products) and cathinones (22 products), whereas lidocaine only with the latter class (47 products). A great inconsistency in the qualitative and quantitative composition of products with identical labelling was shown in an example of Coco products seized after August 2010; we found 10 different single component or mixture preparations, and the content of individual ingredients varied from several to hundreds of mgs. This paper summarizes potential dangers connected with the uncontrolled sale of psychoactive substances, and indicates important issues concerning the analysis of legal highs. © 2012 John Wiley & Sons, Ltd.

Sekula K.,Institute of Forensic Research
Journal of mass spectrometry : JMS | Year: 2012

'Herbal highs' have been advertised as legal and natural substitutes to cannabis, but a detailed examination of these products has revealed that the herbal matrix is laced with synthetic substances that mimic the effects of marijuana. Producers select the ingredients based on the results of scientific studies on the affinities of different chemicals to cannabinoid receptors. Naphthoylindoles have turned out to be the most popular class of substances identified in the products. Legal actions taken in order to tackle the problem of uncontrolled access to one substance have usually resulted in the marketing of derivatives or analogues. In the study, the mass spectral behavior of twelve synthetic cannabinoids from the naphthoylindole family under electrospray ionization (ESI) was investigated. LC-QTOFMS experiments were performed in three modes (low fragmentor voltage, high fragmentor voltage with/without collision energy), and they enabled the identification of protonated molecules and main ions. A general fragmentation pattern under this ionization method was proposed, and mechanisms of ion formation were discussed. The developed procedure allowed the determination of substituent groups of the core naphthoylindole structure and distinction between positional isomers. The obtained results were used for the prediction of the ESI-MS spectra for many naphthoylindoles with a high affinity to cannabinoid receptors. Similarities and differences between ESI-MS and electron impact-MS spectra of naphthoylindoles were discussed. The developed identification process was presented on an example of an analysis of an unknown herbal material, in which JWH-007 was finally identified. Knowledge of the fragmentation mechanisms of naphthoylindoles could also be used by other researchers for identification of unknown substances in this chemical family. Copyright © 2012 John Wiley & Sons, Ltd.

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