Journal Cover Forensic Science International
  [SJR: 1.21]   [H-I: 88]   [446 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0379-0738
   Published by Elsevier Homepage  [3118 journals]
  • The cutting edge — Micro-CT for quantitative toolmark analysis of
           sharp force trauma to bone
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): D.G. Norman, D.G. Watson, B. Burnett, P.M. Fenne, M.A. Williams
      Toolmark analysis involves examining marks created on an object to identify the likely tool responsible for creating those marks (e.g., a knife). Although a potentially powerful forensic tool, knife mark analysis is still in its infancy and the validation of imaging techniques as well as quantitative approaches is ongoing. This study builds on previous work by simulating real-world stabbings experimentally and statistically exploring quantitative toolmark properties, such as cut mark angle captured by micro-CT imaging, to predict the knife responsible. In Experiment 1 a mechanical stab rig and two knives were used to create 14 knife cut marks on dry pig ribs. The toolmarks were laser and micro-CT scanned to allow for quantitative measurements of numerous toolmark properties. The findings from Experiment 1 demonstrated that both knives produced statistically different cut mark widths, wall angle and shapes. Experiment 2 examined knife marks created on fleshed pig torsos with conditions designed to better simulate real-world stabbings. Eight knives were used to generate 64 incision cut marks that were also micro-CT scanned. Statistical exploration of these cut marks suggested that knife type, serrated or plain, can be predicted from cut mark width and wall angle. Preliminary results suggest that knives type can be predicted from cut mark width, and that knife edge thickness correlates with cut mark width. An additional 16 cut marks walls were imaged for striation marks using scanning electron microscopy with results suggesting that this approach might not be useful for knife mark analysis. Results also indicated that observer judgements of cut mark shape were more consistent when rated from micro-CT images than light microscopy images. The potential to combine micro-CT data, medical grade CT data and photographs to develop highly realistic virtual models for visualisation and 3D printing is also demonstrated. This is the first study to statistically explore simulated real-world knife marks imaged by micro-CT to demonstrate the potential of quantitative approaches in knife mark analysis. Findings and methods presented in this study are relevant to both forensic toolmark researchers as well as practitioners. Limitations of the experimental methodologies and imaging techniques are discussed, and further work is recommended.

      PubDate: 2018-01-10T09:47:09Z
       
  • Dependence among randomly acquired characteristics on shoeprints and their
           features
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Naomi Kaplan Damary, Micha Mandel, Sarena Wiesner, Yoram Yekutieli, Yaron Shor, Clifford Spiegelman
      Randomly acquired characteristics (RACs), also known as accidental marks, are random markings on a shoe sole, such as scratches or holes, that are used by forensic experts to compare a suspect's shoe with a print found at the crime scene. This article investigates the relationships among three features of a RAC: its location, shape type and orientation. If these features, as well as the RACs, are independent of each other, a simple probabilistic calculation could be used to evaluate the rarity of a RAC and hence the evidential value of the shoe and print comparison, whereas a correlation among the features would complicate the analysis. Using a data set of about 380 shoes, it is found that RACs and their features are not independent, and moreover, are not independent of the shoe sole pattern. It is argued that some of the dependencies found are caused by the elements of the sole. The results have important implications for the way forensic experts should evaluate the degree of rarity of a combination of RACs.

      PubDate: 2018-01-10T09:47:09Z
       
  • Quantifying human decomposition in an indoor setting and implications for
           postmortem interval estimation
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Ann-Sofie Ceciliason, M. Gunnar Andersson, Anders Lindström, Håkan Sandler
      This study’s objective is to obtain accuracy and precision in estimating the postmortem interval (PMI) for decomposing human remains discovered in indoor settings. Data were collected prospectively from 140 forensic cases with a known date of death, scored according to the Total Body Score (TBS) scale at the post-mortem examination. In our model setting, it is estimated that, in cases with or without the presence of blowfly larvae, approximately 45% or 66% respectively, of the variance in TBS can be derived from Accumulated Degree-Days (ADD). The precision in estimating ADD/PMI from TBS is, in our setting, moderate to low. However, dividing the cases into defined subgroups suggests the possibility to increase the precision of the model. Our findings also suggest a significant seasonal difference with concomitant influence on TBS in the complete data set, possibly initiated by the presence of insect activity mainly during summer. PMI may be underestimated in cases with presence of desiccation. Likewise, there is a need for evaluating the effect of insect activity, to avoid overestimating the PMI. Our data sample indicates that the scoring method might need to be slightly modified to better reflect indoor decomposition, especially in cases with insect infestations or/and extensive desiccation. When applying TBS in an indoor setting, the model requires distinct inclusion criteria and a defined population.

      PubDate: 2018-01-10T09:47:09Z
       
  • Some inconsistencies in Demirjian’s method
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Giuseppe Quaremba, Claudio Buccelli, Vincenzo Graziano, Alberto Laino, Luigi Laino, Mariano Paternoster, Pierpaolo Petrone
      Nowadays, given the massive migration movements toward and across EU countries, age assessment can be highly useful for estimating the real age of asylum seekers or in medico-legal assessments of age-disputed children charged with criminal acts. Demirjian et al.’s dental maturity score is currently a dental scoring system universally adopted for age assessment of unidentified children. Here we explore the biological compatibility of Demirjian’s scores with respect to the estimation of certain chronological ages of forensic interest through an algorithm based on the theory of constrained graphs integrated with combinatory analysis. Rather than simply respect Demirjian’s indications (direct method) on a sample of children, we followed a reverse procedure (indirect method) as follows: i. chronological age selection and identification of the corresponding maturity score (MS); ii. determination of all the possible combinations of dental maturity stages whose sum of the scores is equal to the MS under consideration; iii. checking for all such possible combinations the biological congruity of the state of maturity of each tooth compared to the chronological age initially chosen. By evidencing dental development inconsistencies, our mathematical approach explains why Demirjian’s method typically overestimates age. Therefore, even if the method in question remains the recommended way to assess individual dental maturity, it should definitely be considered unsuitable for application in certain forensic scenarios, particularly as regards the most disputed age range 14–16 years.

      PubDate: 2018-01-10T09:47:09Z
       
  • Organic staining on bone from exposure to wood and other plant materials
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Corey R. Pollock, James T. Pokines, Jonathan D. Bethard
      Determining the depositional environment and the postmortem alterations to a set of remains are necessary aspects of a forensic investigation to explain the circumstances surrounding the death of an individual. The present study examines organic staining as a method for reconstructing the depositional environment of skeletal remains and the taphonomic agents with which they came into contact. Organic staining results largely from tannins leaching from plant materials and therefore can be seen on bone deposited in wooden coffin environments or on terrestrial surfaces. The present study examines the hypothesis that the degree of staining observed on skeletal elements would increase as the length of exposure to the organic matter increased and that different plant materials and environments would leave different patterns or colorations of staining. The sample consisted of 165 pig (Sus scrofa) femora divided into four groups exposed to differing experimental conditions, including burial in direct contact with soil or burial in a simulated coffin environment, immersion in water with wood samples, and surface deposition with plant matter contact. The bones were removed once a month from their experimental environments and the level of staining was recorded qualitatively using the Munsell Soil Color Chart. In all of the experimental environments, staining was present after two months of exposure, and the color darkened across the bone surface with each episode of data collection. The results from the present study indicate that staining can manifest on bone within a relatively short time frame once skeletonization occurs and a variety of colorations or patterns of staining can manifest based on the plant material. The present research also demonstrates the potential of organic staining to aid in estimations of the postmortem interval as well as a depositional environmental reconstruction through plant species identification.

      PubDate: 2018-01-10T09:47:09Z
       
  • Formation of phosphatidylethanol from endogenous phosphatidylcholines in
           animal tissues from pig, calf, and goat
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Marc Luginbühl, Sytske Willem, Stefan Schürch, Wolfgang Weinmann
      In the presence of alcohol, phosphatidylcholine (PC) is transformed to the direct alcohol biomarker phosphatidylethanol (PEth). This reaction is catalyzed by the enzyme phospholipase D (PLD) and dependent on substrate availability. As recent methods have solely focused on the determination of PEth, information about the PC composition was generally missing. To address this issue and monitor PC (16:0/18:1 and 16:0/18:2) and PEth (16:0/18:1 and 16:0/18:2) simultaneously, a reversed phase LC–MS/MS method based on a C8 core–shell column, coupled to a Sciex 5500 QTrap instrument was developed. By application of polarity switching, at first, PC was measured in ESI positive SRM mode, while PEth was determined at a later stage in ESI negative SRM mode. The PEth method was validated for human blood samples to show its robustness and subsequently applied for the investigation of systematic in vitro PEth formation in animal tissue samples (brain, kidney, liver, and blood) from a pig, a calf, and a goat. Homogenized tissue was incubated at 37°C with varying ethanol concentrations from 1 to 7g/kg (determined by HS-GC-FID) for 5h, whereby a sample was taken every 30min. For all tissue samples, an increase in PEth was measurable. PEth concentrations formed in blood remained below the LLOQ, in agreement with literature. Data analysis of Michaelis–Menten kinetics and PC within the tissue provided a detailed insight about PEth formation, as the occurrence of PEth species can be linked to the observed PC composition. The results of this study show that PEth formation rates vary from tissue to tissue and among different species. Furthermore, new recommendations for PEth analysis are presented.
      Graphical abstract image

      PubDate: 2018-01-10T09:47:09Z
       
  • Corrigendum to “Differences in combinations and concentrations of drugs
           of abuse in fatal intoxication and driving under the influence cases”
           [Forensic Sci. Int. 281 (2017) 127–133]
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Hilde Erøy Edvardsen, Torill Tverborgvik, Joachim Frost, Sidsel Rogde, Inge Morild, Helge Waal, Thomas Clausen, Lars Slørdal, Vigdis Vindenes


      PubDate: 2018-01-10T09:47:09Z
       
  • Dental age assessment: which is the most applicable method'
    • Abstract: Publication date: Available online 8 January 2018
      Source:Forensic Science International
      Author(s): Luciana Jácome Lopes, Helena Aguiar Ribeiro Nascimento, Giovanna Panebianchi Lima, Luís Antônio Nogueira dos Santos, Dagmar de Paula Queluz, Deborah Queiroz Freitas
      To evaluate which method is the most applicable for estimating estimate dental age in Brazilian children, Nolla or Demirjian. For this purpose, both methods were reviewed and the differences between them brought to light. A total of 403 healthy children between the ages of 7 and 13 years with satisfactory panoramic radiographs, similar socio-economic background and ethnic origin were included. Panoramic radiographs were examined by the Nolla and Demirjian methods. Dental age was calculated for both methods, and the differences between the dental age and the chronological age were compared with analysis of variance with post-hoc Dunnett. The Nolla method showed no significant difference in relation to chronological age in the majority of age groups for boys and girls, except for 12-year-old boys (over-estimation of 1.00) and between 11- and 12-year-old girls (over-estimation of 0.51 and 0.59, respectively). An over-estimation of the dental age was observed by using the Demirjian method (for boys 0.89-1.84 and for girls 0.69-1.97) for all age groups. The Nolla method is suitable for Brazilian children when it comes to age estimate with care to growth spurt beginning (around 11 and 12 years). However, the Dermijian method should not be used, because it over-estimated the age in both sexes.

      PubDate: 2018-01-10T09:47:09Z
       
  • Assessment of second (I2M) and third (I3M) molar indices for establishing
           14 and 16 legal ages and validation of the Cameriere’s I3M cut-off for
           18 years old in Chilean population
    • Abstract: Publication date: Available online 8 January 2018
      Source:Forensic Science International
      Author(s): Roberto Cameriere, Luz Andrea Velandia Palacio, Jorge Pinares, Fiorella Bettesti, Rossella Paba, Erminia Coccia, Luigi Ferrante
      This retrospective cross-sectional study has two-fold aims: the first is to assess new cut-offs at the legal age thresholds (LATs) of 14 and 16 years old and the second is to validate the cut-off of third molar index I3M =0.08 for 18 years of age in Chilean people. Orthopantomographs from 822 Chilean children aged from 11 to 22 (472 girls and 350 boys) were analysed. For LAT of 14 years, cut-offs were found using the ROC curves singly for boys and girls. The cut-offs for boys were I2M =0.16 and I3M =0.73 while for girls we obtained I2M =0.10 and I3M =0.77. For LAT of 16 years we obtained the same cut-offs regardless of gender, which were 0.06 and 0.36 for I2M and I3M respectively. Concerning the validity of I3M cut-off for 18 years old in Chilean population, the proportion of correctly classified individuals was 83% and estimated post-test probability, PPV, was 93.2%, with a 95% confidence interval equals to 91.3%, 94.6%. Hence, the probability that a subject positive on the test was 18 years of age or older was 93.2%, confirming the validation of the I3M cut-off for Chilean population.

      PubDate: 2018-01-10T09:47:09Z
       
  • Development and validation of rapid and simultaneous method for
           determination of 12 hair-growth compounds in adulterated products by
           UHPLC-MS/MS
    • Abstract: Publication date: Available online 8 January 2018
      Source:Forensic Science International
      Author(s): Han Na Park, Ji Hyun Lee, Sung-Kwan Park, Sun Young Baek, Yong-Moon Lee, Hoil Kang
      Synthetic hair-growth compounds have been illegally used in diverse products to enhance the short-term efficacy of these products. In this study, a rapid and simultaneous method for the determination of hair-growth compounds in adulterated products based on ultra high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. The limit of detection (LOD) and limit of quantitation (LOQs) of the method were 0.08–43.6ng/mL and 0.27–145ng/mL for the solid-, liquid-, and cream-type samples, respectively. Good calibration linearity for all compounds was demonstrated with a correlation coefficient (r2) higher than 0.997. The intra- and inter-assay precisions were within 11%. The corresponding accuracies were 86–117% and 81–113%, respectively. The mean recoveries obtained for the solid-, liquid, and cream-type samples ranged from 87 to 114%, with a relative standard deviation (RSD) within 6%. The RSD of the stability evaluated at 4°C for 48h was less than 6%. The established method was used to screen 76 samples advertised as hair- growth treatments, from online and offline markets, over the course of two years. In 10% of the samples, four compounds, including triaminodil, minoxidil, finasteride, methyltestosterone, and testosterone-propionate were detected. The concentrations were in the range of 0.5–16.4mg/g. This technique provides a reliable platform for technical analysis for continuous monitoring of adulterated products to protect public health.

      PubDate: 2018-01-10T09:47:09Z
       
  • Quantification of spheno-occipital synchondrosis fusion in a contemporary
           Malaysian population
    • Abstract: Publication date: Available online 8 January 2018
      Source:Forensic Science International
      Author(s): Salina Hisham, Ambika Flavel, Nurliza Abdullah, Mohamad Helmee Mohamad Noor, Daniel Franklin
      Timing of fusion of the spheno-occipital synchondrosis (SOS) is correlated with age. Previous research, however, has demonstrated variation in the timing of closure among different global populations. The present study aims to quantify the timing of SOS fusion in Malaysian individuals as visualised in multi-detector computed tomography (CT) scans and to thereafter formulate age estimation models based on fusion status. Anonymised cranial CT scans of 336 males and 164 females, aged 5 to 25 years, were acquired from the National Institute of Forensic Medicine, Hospital Kuala Lumpur and Department of Diagnostic Imaging, Hospital Sultanah Aminah. The scans were received in DICOM format and reconstructed into three-dimensional images using OsiriX. The SOS is scored as open, fusing endocranially, fusing ectocranially or completely fused. Statistical analyses are performed using IBM SPSS Statistics version 24. Transition analysis (Nphases2) is then utilised to calculate age ranges for each stage. To assess the reliability of an observation, intra- and inter-observer agreement is quantified using Fleiss Kappa and was found to be excellent (κ=0.785-0.907 and 0.812). The mean (SD) age for complete fusion is 20.84 (2.84) years in males and 19.78 (3.35) years in females. Transition ages between Stages 0 and 1, 1 and 2, and 2 and 3 in males are 12.52, 13.98 and 15.52 years, respectively (SD 1.37); in females, the corresponding data are 10.47, 12.26 and 13.80 years (SD 1.72). Complete fusion of the SOS was observed in all individuals above the age of 18 years. SOS fusion status provides upper and lower age boundaries for forensic age estimation in the Malaysian sample.

      PubDate: 2018-01-10T09:47:09Z
       
  • Forensic Genetic Analysis of Bone Remain Samples
    • Abstract: Publication date: Available online 8 January 2018
      Source:Forensic Science International
      Author(s): T. Siriboonpiputtana, T. Rinthachai, J. Shotivaranon, V. Peonim, B. Rerkamnuaychoke
      DNA typing from degraded human remains is still challenging forensic DNA scientists not only in the prospective of DNA purification but also in the interpretation of established DNA profiles and data manipulation, especially in mass fatalities. In this report, we presented DNA typing protocol to investigate many skeletal remains in different degrees of decomposing. In addition, we established the grading system aiming for prior determination of the association between levels of decomposing and overall STR amplification efficacy. A total of 80 bone samples were subjected to DNA isolation using the modified DNA IQ™ System (Promega, USA) for bone extraction following with STR analysis using the AmpFLSTR Identifiler® (Thermo Fisher Scientific, USA). In low destruction group, complete STR profiles were observed as 84.4% whereas partial profiles and non-amplified were found as 9.4% and 6.2%, respectively. Moreover, in medium destruction group, both complete and partial STR profiles were observed as 31.2% while 37.5% of this group was unable to amplify. Nevertheless, we could not purify DNA and were unable to generate STR profile in any sample from the high destroyed bone samples. Compact bones such as femur and humerus have high successful amplification rate superior than loose/spongy bones. Furthermore, costal cartilage could be a designate specimen for DNA isolation in a case of the body that was discovered approximately to 3 days after death which enabled to isolate high quality and quantity of DNA, reduce time and cost, and do not require special tools such as freezer mill.

      PubDate: 2018-01-10T09:47:09Z
       
  • The UK National DNA Database: implementation of the Protection of Freedoms
           Act 2012
    • Abstract: Publication date: Available online 5 January 2018
      Source:Forensic Science International
      Author(s): Aaron Opoku Amankwaa, Carole McCartney
      In 2008, the European Court of Human Rights, in S and Marper v the United Kingdom, ruled that a retention regime that permits the indefinite retention of DNA records of both convicted and non-convicted (“innocent”) individuals is disproportionate. The court noted that there was inadequate evidence to justify the retention of DNA records of the innocent. Since the Marper ruling, the laws governing the taking, use, and retention of forensic DNA in England and Wales have changed with the enactment of the Protection of Freedoms Act 2012 (PoFA). This Act, put briefly, permits the indefinite retention of DNA profiles of most convicted individuals and temporal retention for some first-time convicted minors and innocent individuals on the National DNA Database (NDNAD). The PoFA regime was implemented in October 2013. This paper examines ten post-implementation reports of the NDNAD Strategy Board (3), the NDNAD Ethics Group (3) and the Office of the Biometrics Commissioner (OBC) (4). Overall, the reports highlight a considerable improvement in the performance of the database, with a current match rate of 63.3%. Further, the new regime has strengthened the genetic privacy protection of UK citizens. The OBC reports detail implementation challenges ranging from technical, legal and procedural issues to sufficient understanding of the requirements of PoFA by police forces. Risks highlighted in these reports include the deletion of some “retainable” profiles, which could potentially lead to future crimes going undetected. A further risk is the illegal retention of some profiles from innocent individuals, which may lead to privacy issues and legal challenges. In conclusion, the PoFA regime appears to be working well, however, critical research is still needed to evaluate its overall efficacy compared to other retention regimes.

      PubDate: 2018-01-10T09:47:09Z
       
  • Corrigendum to “The presence of licit and illicit drugs in police
           stations and their implications for workplace drug testing” [Forensic
           Sci. Int. 278C (2017) 125–136]
    • Abstract: Publication date: Available online 5 January 2018
      Source:Forensic Science International
      Author(s): Gregory S. Doran, Ralph Deans, Carlo De Filippis, Chris Kostakis, Julia A. Howitt


      PubDate: 2018-01-10T09:47:09Z
       
  • Molecular identification of forensically important calliphoridae and
           sarcophagidae species using ITS2 nucleotide sequences
    • Abstract: Publication date: Available online 3 January 2018
      Source:Forensic Science International
      Author(s): Ji Hye Park, Yu-Hoon Kim, Chan Seon Ham, Sang Eon Shin, Hyun Ju Lee, Kwang Soo Ko, Jinhyuk Choi, Gi Hoon Son, Seong Hwan Park
      The application of insect evidence to forensic investigations is mainly based on the estimation of postmortem interval and the identification of insect species from samples that are collected from the crime scene. Due to the limited number of expert taxonomists, species identification is one of the major barriers for crime scene investigators to utilize forensic entomology. Therefore, the molecular identification of species, using mitochondrial cytochrome c oxidase subunit I (COI) gene, has been suggested as an alternative strategy. However, in some cases, these maternally inherited markers cause confusion; hence, nuclear DNA markers such as ITS2 are also required as supporting tools. Eleven Calliphoridae and 5 Sarcophagidae fly species collected from Korea were utilized for PCR amplification and nucleotide sequencing of ITS2 locus. Species Identifier software was used for sequence analysis and comparison. The results demonstrated that 11 Korean Calliphoridae and 5 Korean Sarcophagidae fly species could be distinguished using ITS2 nucleotide sequences. In particular, the sister species, Lucilia illustris and Lucilia caesar were also distinguished, despite the very low level of interspecific diversity. However, when compared with previously reported ITS2 nucleotide sequences, several identification failures were noted. This is the first study that widely analyzed nucleotide sequences of the ITS2 locus from Calliphoridae and Sarcophagidae fly species collected in Korea.

      PubDate: 2018-01-10T09:47:09Z
       
  • Characterising the online weapons trafficking on cryptomarkets
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Damien Rhumorbarbe, Denis Werner, Quentin Gilliéron, Ludovic Staehli, Julian Broséus, Quentin Rossy
      Weapons related webpages from nine cryptomarkets were manually duplicated in February 2016. Information about the listings (i.e. sales proposals) and vendors’ profiles were extracted to draw an overview of the actual online trafficking of weapons. Relationships between vendors were also inferred through the analysis of online digital traces and content similarities. Weapons trafficking is mainly concentrated on two major cryptomarkets. Besides, it accounts for a very small proportion of the illicit trafficking on cryptomarkets compared to the illicit drugs trafficking. Among all weapon related listings (n=386), firearms only account for approximately 25% of sales proposal since the proportion of non-lethal and melee weapons is important (around 46%). Based on the recorded pseudonyms, a total of 96 vendor profiles were highlighted. Some pseudonyms were encountered on several cryptomarkets, suggesting that some vendors may manage accounts on different markets. This hypothesis was strengthened by comparing pseudonyms to online traces such as PGP keys, images and profiles descriptions. Such a method allowed to estimate more accurately the number of vendors offering weapons across cryptomarkets. Finally, according to the gathered data, the extent of the weapons trafficking on the cryptomarkets appear to be limited compared to other illicit goods.

      PubDate: 2018-01-02T14:44:36Z
       
  • Fast screening tests for the simultaneous detection of 11 drugs of abuse
           in urine specimens. A forensic epidemiology study of 28,298 cases in
           Tunisia
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): B. Moslah, M. Araoud, M.A. Nouioui, S. Najjar, D. Amira, A. Hedhili, N. Ben Salah
      Forensic investigation performed on people suspected to be drug abusers covering all Tunisian cities was conducted by monitoring an epidemiological study of human urine samples surveying positive rates of consumption for drugs of abuse. The forensic investigations were conducted on a total of 28,298 arrested individuals suspected to be drug addicts during five years (January 2010–December 2015). An immunoassay screening tests to detect elevated levels of drugs classes in urine samples was performed. These screening assays provide a preliminary qualitative test result. Only positives urine specimens were analyzed with GC–MS for confirmation. Except for cannabis, the results showed insignificant number of positive cases for cocaine, ecstasy (MDMA) and amphetamine consumptions (<1%).

      PubDate: 2018-01-02T14:44:36Z
       
  • Sensitive and rapid determination of glyphosate, glufosinate, bialaphos
           and metabolites by UPLC–MS/MS using a modified Quick Polar Pesticides
           Extraction method
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Hao Guo, Huijun Wang, Jing Zheng, Wenwen Liu, Jian Zhong, Qingbiao Zhao
      Phosphoric acid-containing amino acid pesticides, including glyphosate, glufosinate, and bialaphos, have been frequently encountered in human poisoning and suicidal cases, thus a quick and sensitive determination method for these compounds is very important. Herein we report a sensitive and rapid method for the determination of glyphosate, glufosinate, bialaphos and their metabolites, aminomethylphosphonic acid (AMPA) and 3-methylphosphinicopropionic acid (MPPA) in human blood samples. The method involves extraction using a modified Quick Polar Pesticides Extraction (QuPPe) method, cleanup with the PRiME HLB sorbents and detection with ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). The LODs were 0.02mg/L for glyphosate, glufosinate and AMPA, 0.01mg/L for bialaphos and MPPA, with the analysis time as short as ∼6min. To the best of our knowledge, the LODs are lower and the analysis time is shorter than previous reports on determination of these compounds in blood and serum samples. The method was successfully applied to the detection and quantification of glyphosate and AMPA for blood samples from real forensic cases. This extremely rapid determination method with high sensitivity is of significant importance, particularly for forensic cases where quick determination is vital.

      PubDate: 2018-01-02T14:44:36Z
       
  • Effect of water immersion on multi- and mono-metallic VMD
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Romain Steiner, Andy Bécue
      The use of vacuum metal deposition (VMD) for fingermark detection has been known for almost 40 years. The technique is applicable on a wide variety of substrates and on wetted items. Several publications compare the relative efficiency of VMD (conventionally based on a successive vaporization of gold followed by zinc) with other detection techniques, or its ability to detect marks on difficult substrates, but few are known about the application of monometallic VMDs and about the impact of immersion on the detection performances. This study aims at partially filling that gap by offering a quantitative and qualitative glance at three VMD processes (i.e., gold/zinc, silver, and sterling silver) applied to dry and wetted substrates. The impact of immersion on the detection process has been studied by using split marks (one half kept dry, the other one wetted). On immersed substrates, a modification of colour shades has been observed with monometallic VMDs (on all substrates considered) and of contrast with conventional VMD (on polyethylene). In terms of ridge details, a relatively good resistance of secretion residue towards immersion has been emphasized (in regards with VMD). This study provides original data, which will hopefully help getting a better understanding of the VMD detection mechanism.
      Graphical abstract image

      PubDate: 2018-01-02T14:44:36Z
       
  • Validity and accuracy of three radiographic dental age estimation methods
           in Brazilians
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Eduardo Novaes Benedicto, Alana Cássia Silva Azevedo, Edgard Michel-Crosato, Maria Gabriela Haye Biazevic
      Objective To validate, analyse accuracy, and construct multiple regression formulae of three age estimation methods — Liliequist and Lundberg, Haavikko, and Mornstad — using mineralization stages of permanent teeth in Brazilians. Methods Panoramic radiographs of 1009 Brazilian children and adolescents (387 males and 622 females) aged 8–15.99 years were analysed using the aforementioned methodologies. Results The overall accuracy (absolute difference=AD and dental age–chronological age=DA–CA) of the methods was as follows: Liliequist and Lundberg, AD=0.97 and DA–CA=−0.58; Haavikko, AD=1.42 and DA–CA=−1.35; and Mornstad, AD=2.48 and DA–CA=0.78. After sex-based stratification, the values for males were as follows: Liliequist and Lundberg, AD=0.91 and DA–CA=−0.45; Haavikko, AD=1.80 and DA–CA=−1.75; and Mornstad, AD=2.74 and DA–CA=1.17. In females, the values were as follows: Liliequist and Lundberg, DA=1.01 and DA–CA=−0.67; Haavikko, AD=1.17 and DA–CA=−1.09; and Mornstad, AD=2.31 and DA–CA=0.53. The Liliequist and Lundberg technique predominated, followed by Haavikko and Mornstad when distinction was present between sex and age. Multiple regression formulae were constructed from the data presented for the Liliequist and Lundberg, Haavikko and Mornstad methodologies. Conclusions The validation of the methodologies in the Brazilian population is possible. The Liliequist and Lundberg method most closely represented the Brazilian sample.

      PubDate: 2018-01-02T14:44:36Z
       
  • Factors associated with trace evidence analyses and DNA findings among
           police reported cases of rape
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Camilla Forr, Berit Schei, Lise Eilin Stene, Kari Ormstad, Cecilie Therese Hagemann
      Objective The aim of this study was to examine the association between victim, suspect and assault characteristics and (1) forensic analysis of trace evidence, (2) detection of spermatozoa and (3) DNA match in police-reported cases of rape/attempted rape. In addition, we explored whether DNA findings were associated with legal outcome. Methods We conducted a retrospective, descriptive study based on police-reported rapes and attempted rapes of women  ≥16 years of age in Sør-Trøndelag Police District throughout 1997–2010. Police data were merged with information from the Sexual Assault Centre (SAC) at St. Olavs University Hospital, Trondheim, Norway. We used binary and multivariable logistic regression for the comparisons. Results We identified 324 victims (mean age 24 years). The police requested analysis in 135 (45%) of the 299 collected victim samples. The police decision to analyze was after adjustment associated with the victim being employed or under education, and a public venue, but not with interval from assault to sampling. Spermatozoa were detected in 79 (61%) of the analyzed cases, of which 71 were collected from victims within 24h. Interval from assault being <24h and reporting a penetrative assault remained associated with the findings of spermatozoa after adjustments. Forensic analyses of trace evidence collected from victim, suspect and/or venue disclosed matching DNA profiles in 57 (40%) of a total of 143 analyzed cases. Matching DNA profiles were associated with suspect being known to the victim and with the venue being private. A higher proportion of cases with a DNA match were prosecuted in court: 20 of the 29 cases prosecuted. However, despite a DNA match 35 cases were anyway dismissed because of insufficient evidence. Conclusions Although many of the associations in our study were expected, it is still important to report the actual numbers to gain insight into the importance of a DNA match in legal proceedings. A substantial proportion of cases with DNA match was dismissed because of insufficient evidence. To strengthen the justice response to sexual assault, it is essential to generate knowledge about the role of medico-legal evidence in such cases, and there are obviously other non-medical factors influencing the legal decisions.

      PubDate: 2018-01-02T14:44:36Z
       
  • Neither femur nor tooth: Petrous bone for identifying archaeological bone
           samples via forensic approach
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Elena Pilli, Stefania Vai, Marina Grazia Caruso, Giancarlo D’Errico, Andrea Berti, David Caramelli
      One of the major challenges of molecular biology in anthropological analysis is the identification via DNA typing of bone or teeth samples that can be collected from archaeological site in order to investigate kinship relationships. Due to the difficulties of isolating and analysing DNA from such samples, several efforts have been made to solve these problems, but less work has been conducted to identify the proper type of bone samples for the DNA analysis. Therefore, following the promising results obtained from the DNA analysis of petrous bones by different groups of researchers, for the first time, here we investigated the possibility of using petrous bones as skeletal elements useful for short tandem repeat (STR) typing via capillary electrophoresis technique in ancient bone samples. In order to compare the results from petrous bone, femur and tooth samples, a total of 39 skeletal elements were collected from 13 different individuals excavated from Italian archaeological sites, dating from the sixth to seventh century C.E. The DNA was extracted, quantified, and subsequently amplified using two STR multiplex kits. The presence of a good amount of genetic material, despite high degradation, allowed us to quantify and subsequently identify STR profiles via CE analysis from ancient petrous bones that were complete for four out of thirteen samples and higher than 11 autosomal loci for all samples. Our results indicated that petrous bone is the best skeletal element with regard to DNA conservation and is a valuable element from which it is possible to obtain a complete STR profile also when analysing ancient bones. The STR results showed the possibility to use the petrous bones for identification and matching purposes in cases in which the biological material is poor and highly degraded such as in archaeological studies. Therefore, STR typing could represent a time-saving and cheap chance to verify kinship relationships in archaeological sites and evaluate sex when skeletal material is not suitable for morphometric estimate as in case of infants.

      PubDate: 2018-01-02T14:44:36Z
       
  • Considerations regarding the validation of chromatographic mass
           spectrometric methods for the quantification of endogenous substances in
           forensics
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Cornelius Hess, Konrad Sydow, Theresa Kueting, Michael Kraemer, Alexandra Maas
      The requirement for correct evaluation of forensic toxicological results in daily routine work and scientific studies is reliable analytical data based on validated methods. Validation of a method gives the analyst tools to estimate the efficacy and reliability of the analytical method. Without validation, data might be contested in court and lead to unjustified legal consequences for a defendant. Therefore, new analytical methods to be used in forensic toxicology require careful method development and validation of the final method. Until now, there are no publications on the validation of chromatographic mass spectrometric methods for the detection of endogenous substances although endogenous analytes can be important in Forensic Toxicology (alcohol consumption marker, congener alcohols, gamma hydroxy butyric acid, human insulin and C-peptide, creatinine, postmortal clinical parameters). For these analytes, conventional validation instructions cannot be followed completely. In this paper, important practical considerations in analytical method validation for endogenous substances will be discussed which may be used as guidance for scientists wishing to develop and validate analytical methods for analytes produced naturally in the human body. Especially the validation parameters calibration model, analytical limits, accuracy (bias and precision) and matrix effects and recovery have to be approached differently. Highest attention should be paid to selectivity experiments.

      PubDate: 2018-01-02T14:44:36Z
       
  • Are we using the appropriate reference samples to develop juvenile age
           estimation methods based on bone size' An exploration of growth
           differences between average children and those who become victims of
           homicide
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Laure Spake, Hugo F.V. Cardoso
      The population on which forensic juvenile skeletal age estimation methods are applied has not been critically considered. Previous research suggests that child victims of homicide tend to be from socioeconomically disadvantaged contexts, and that these contexts impair linear growth. This study investigates whether juvenile skeletal remains examined by forensic anthropologists are short for age compared to their normal healthy peers. Cadaver lengths were obtained from records of autopsies of 1256 individuals, aged birth to eighteen years at death, conducted between 2000 and 2015 in Australia, New Zealand, and the U.S. Growth status of the forensic population, represented by homicide victims, and general population, represented by accident victims, were compared using height for age Z-scores and independent sample t-tests. Cadaver lengths of the accident victims were compared to growth references using one sample t-tests to evaluate whether accident victims reflect the general population. Homicide victims are shorter for age than accident victims in samples from the U.S., but not in Australia and New Zealand. Accident victims are more representative of the general population in Australia and New Zealand. Different results in Australia and New Zealand as opposed to the U.S. may be linked to socioeconomic inequality. These results suggest that physical anthropologists should critically select reference samples when devising forensic juvenile skeletal age estimation methods. Children examined in forensic investigations may be short for age, and thus methods developed on normal healthy children may yield inaccurate results. A healthy reference population may not necessarily constitute an appropriate growth comparison for the forensic anthropology population.

      PubDate: 2018-01-02T14:44:36Z
       
  • Alcohol and illicit drugs in drivers involved in road traffic crashes in
           the Milan area. A comparison with normal traffic reveals the possible
           inadequacy of current cut-off limits
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Davide Ferrari, Monica Manca, Giuseppe Banfi, Massimo Locatelli
      Background Driving under the influence of alcohol and/or illicit drugs in Italy is regulated by the articles 186 and 187 of the National Street Code. Epidemiological studies on drivers involved in road traffic crashes (RTC) provide useful information about the use/abuse of these substances in the general population. Comparison with case control studies may reveal important information like the cut-off limits adequacy. Methods Data from 1587 blood tests for alcohol and 1258 blood tests for illicit drugs on drivers involved in RTC around Milan between 2012 and 2016, were analyzed and compared with a published random survey (DRUID) from the European Community. Results Our data from RTC-involved drivers show that alcohol abuse is not age-related whereas illicit drugs are more common in young people. Cannabinoids are frequent among younger drivers (median age 27) whereas cocaine is more often detected in adults (median age 34). The calculated odds ratio after comparison with the DRUID survey shows that a blood alcohol concentration below the legal limit does not represent a risk factor in having a car accident whereas concentrations of cocaine and cannabinoids within the legal limits are associated with being involved in a car accident. Conclusions Despite authority efforts, the abuse of alcohol and illicit drugs is still common in young drivers. We suspect that the cut-off limits for cannabinoids and cocaine and/or the pre-analytical procedures for these substances are inadequate. We suggest a better standardization of the procedure by shortening the time interval between the request for investigation and blood collection and propose the adoption of more stringent cut-off limits.

      PubDate: 2018-01-02T14:44:36Z
       
  • Slight variations of breech face marks and firing pin impressions over
           3070 consecutive firings evaluated by Evofinder®
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Kaifeng Zhang, Yaping Luo
      To investigate if and how the breech face mark and firing pin impression change over repeated firings, we used an automated ballistic identification system Evofinder® to study cartridge cases fired from five Chinese Norinco QSZ-92 9×19mm pistols. Each pistol fired 3070 consecutive shots. The first 20 cartridge cases were all introduced into the system. From the 21st until the 3070th shot, every ten cartridge cases were collected and one random sample of each group was introduced as the 30th, 40th, …, 3070th round. Thus, we introduced 325 specimens for each pistol and established a database of 1625 specimens. We used the first and every 100th specimen of each firearm to start correlations in the database and analyzed the results, especially the results of specimen 0001, 1000, 2000, 3000. Consequently, specimens fired closer in sequence to the specimen under examination had higher similarity scores. In boxplots, the boxes of known match specimens were much higher than boxes of known non match specimens. The Evofinder® ranked nearly all known match specimens in the first position of either firing pin impression list or breech face mark list. In conclusion, the two marks changed over 3070 consecutive shots and cartridge cases of nearer shot numbers were more similar. However, the variations of marks from the same firearm have not exceeded the differences between marks of different firearms and have not hindered the Evofinder® to make nearly 100% correct correlations.

      PubDate: 2017-12-27T14:36:09Z
       
  • The relationship between cross-sectional shapes and FTIR profiles in
           synthetic wig fibers and their discriminating abilities — An evidential
           value perspective
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Theresa A. Joslin Yogi, Michael Penrod, Melinda Holt, Patrick Buzzini
      Wig fragments or fibers may occasionally be recognized as potential physical evidence during criminal investigations. While analytical methods traditionally adopted for the examination of textile fibers are utilized for the characterizations and comparisons of wig specimens, it is essential to understand in deeper detail the valuable contribution of features of these non-routine evidentiary materials as well as the relationship of the gathered analytical data. This study explores the dependence between the microscopic features of cross-sectional shapes and the polymer type gathered by Fourier transform infrared (FTIR) spectroscopy. The discriminating power of the two methods of cross-sectioning and FTIR spectroscopy was also investigated. Forty-one synthetic wigs varying in both quality and price were collected: twenty-three brown, twelve blondes and six black samples. The collected samples were observed using light microscopy methods (bright field illumination and polarized light), before obtaining cross-sections using the Joliff method and analyze them using FTIR spectroscopy. The forty-one samples were divided into ten groups based on one or more of the ten types of cross-sectional shapes that were observed. The majority of encountered cross-sectional shapes were defined as horseshoe, dog bone and lobular. Infrared spectroscopy confirmed modacrylic to be the most prevalent fiber type. Blends of modacrylic and polyvinyl chloride fibers were also observed as well as polypropylene wig samples. The Goodman and Kruskal lambda statistical test was used and showed that the cross-sectional shape and infrared profile were related. From an evidentiary value perspective, this finding has implications when addressing questions about a common source between questioned wig specimens and a wig reference sample.

      PubDate: 2017-12-27T14:36:09Z
       
  • Optimization analysis in reconstruction of vehicle collision accidents
           with deficient EDR data
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Inhwan Han
      This paper presents an efficient method of estimating preimpact and postimpact speeds of the vehicle without an EDR using only the velocity data obtained from a vehicle with an EDR. Using a large amount of data from vehicle collision experiments conducted in various settings, the limitations of collision models involved in optimization methods utilized in this study were found. The practicality of the proposed velocity estimation method was verified by referencing data from vehicle collision accident cases in Korea and America. Not only was the accuracy of the method verified, but the results also showed that the proposed method was applicable even when the EDR data was partially lost.

      PubDate: 2017-12-27T14:36:09Z
       
  • Assessment of the stability of DNA in specimens collected under conditions
           for drug testing—A pilot study
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Robert M. White, John M. Mitchell, E. Dale Hart, Amy Evans, Meredith Meaders, Sarah E. Norsworthy, Eugene D. Hayes, Ron Flegel, George C. Maha, Megan D. Shaffer, Erin M. Hall, Kelley Rogers
      For forensic biological sample collections, the specimen donor is linked solidly to his or her specimen through a chain of custody (CoC) sometimes referenced as a chain of evidence. Rarely, a donor may deny that a urine or oral fluid (OF) specimen is his or her specimen even with a patent CoC. The goal of this pilot study was to determine the potential effects of short-term storage on the quality and quantity of DNA in both types of specimen under conditions that may be encountered with employment-related drug testing specimens. Fresh urine and freshly collected oral fluid all produced complete STR profiles. For the “pad” type OF collectors, acceptable DNA was extractable both from the buffer/preservative and the pad. Although fresh urine and OF produced complete STR profiles, partial profiles were obtained after storage for most samples. An exception was the DNA in the Quantisal OF collector, from which a complete profile was obtained for both freshly collected OF and stored OF.

      PubDate: 2017-12-23T14:29:17Z
       
  • Internal validation of two new retrotransposons-based kits (InnoQuant® HY
           and InnoTyper® 21) at a forensic lab
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Cátia Martins, Paulo Miguel Ferreira, Raquel Carvalho, Sandra Cristina Costa, Carlos Farinha, Luísa Azevedo, António Amorim, Manuela Oliveira
      Obtaining a genetic profile from pieces of evidence collected at a crime scene is the primary objective of forensic laboratories. New procedures, methods, kits, software or equipment must be carefully evaluated and validated before its implementation. The constant development of new methodologies for DNA testing leads to a steady process of validation, which consists of demonstrating that the technology is robust, reproducible, and reliable throughout a defined range of conditions. The present work aims to internally validate two new retrotransposon-based kits (InnoQuant® HY and InnoTyper® 21), under the working conditions of the Laboratório de Polícia Científica da Polícia Judiciária (LPC-PJ). For the internal validation of InnoQuant® HY and InnoTyper® 21 sensitivity, repeatability, reproducibility, and mixture tests and a concordance study between these new kits and those currently in use at LPC-PJ (Quantifiler® Duo and GlobalFiler™) were performed. The results obtained for sensitivity, repeatability, and reproducibility tests demonstrated that both InnoQuant® HY and InnoTyper® 21 are robust, reproducible, and reliable. The results of the concordance studies demonstrate that InnoQuant® HY produced quantification results in nearly 29% more than Quantifiler® Duo (indicating that this new kit is more effective in challenging samples), while the differences observed between InnoTyper® 21 and GlobalFiler™ are not significant. Therefore, the utility of InnoTyper® 21 has been proven, especially by the successful amplification of a greater number of complete genetic profiles (27 vs. 21). The results herein presented allowed the internal validation of both InnoQuant® HY and InnoTyper® 21, and their implementation in the LPC-PJ laboratory routine for the treatment of challenging samples.
      Graphical abstract image

      PubDate: 2017-12-12T14:16:41Z
       
  • Quantitative analysis of drugs in hair by UHPLC high resolution mass
           spectrometry
    • Abstract: Publication date: February 2018
      Source:Forensic Science International, Volume 283
      Author(s): Robert Kronstrand, Malin Forsman, Markus Roman
      Liquid chromatographic methods coupled to high resolution mass spectrometry are increasingly used to identify compounds in various matrices including hair but there are few recommendations regarding the parameters and their criteria to identify a compound. In this study we present a method for the identification and quantification of a range of drugs and discuss the parameters used to identify a compound with high resolution mass spectrometry. Drugs were extracted from hair by incubation in a buffer:solvent mixture at 37°C during 18h. Analysis was performed on a chromatographic system comprised of an Agilent 6550 QTOF coupled to a 1290 Infinity UHPLC system. High resolution accurate mass data were acquired in the All Ions mode and exported into Mass Hunter Quantitative software for quantitation and identification using qualifier fragment ions. Validation included selectivity, matrix effects, calibration range, within day and between day precision and accuracy. The analytes were 7-amino-flunitrazepam, 7-amino-clonazepam, 7-amino-nitrazepam, acetylmorphine, alimemazine, alprazolam, amphetamine, benzoylecgonine, buprenorphine, diazepam, ethylmorphine, fentanyl, hydroxyzine, ketobemidone, codeine, cocaine, MDMA, methadone, methamphetamine, morphine, oxycodone, promethazine, propiomazine, propoxyphene, tramadol, zaleplone, zolpidem, and zopiclone. As proof of concept, hair from 29 authentic post mortem cases were analysed. The calibration range was established between 0.05ng/mg to 5.0ng/mg for all analytes except fentanyl (0.02–2.0), buprenorphine (0.04–2.0), and ketobemidone (0.05–4.0) as well as for alimemazine, amphetamine, cocaine, methadone, and promethazine (0.10–5.0). For all analytes, the accuracy of the fortified pooled hair matrix was 84–108% at the low level and 89–106% at the high level. The within series precisions were between 1.4 and 6.7% and the between series precisions were between 1.4 and 10.1%. From the 29 autopsy cases, 121 positive findings were encountered from 23 of the analytes in concentrations similar to those previously published. We conclude that the developed method proved precise and accurate and that it had sufficient performance for the purpose of detecting regular use of drugs or treatment with prescription drugs. To identify a compound we recommend the use of ion ratios as a complement to instrument software “matching scores”.

      PubDate: 2017-12-12T14:16:41Z
       
  • Influence of alcohol containing and alcohol free cosmetics on FAEE
           concentrations in hair. A performance evaluation of ethyl palmitate as
           sole marker, versus the sum of four FAEEs
    • Abstract: Publication date: Available online 11 December 2017
      Source:Forensic Science International
      Author(s): C. Dumitrascu, R. Paul, R. Kingston, Rachel Williams
      Fatty acid ethyl esters (FAEE) are direct metabolites of ethanol and have been shown to be suitable markers for the evaluation of alcohol consumption. Previous research has suggested that the regular use of alcohol containing cosmetic products can influence the concentration of FAEE detected in hair. In this study we investigated the influence of alcohol containing and alcohol free hair cosmetics (hairspray and waxes) on the FAEE concentrations in hair. The effect of cosmetic treatment was measured against the impact on ethyl palmitate in isolation as compared to the sum of four esters. 10 volunteers treated part of their scalp with cosmetic products every day during a 2 month period (alcohol free hairspray n=2, hairspray containing alcohol (42% by volume) n=3, alcohol free wax n=2, wax containing alcohol (11% by volume) n=3. After the 2 month period of cosmetic application hair samples from volunteers were collected from both sides of the scalp. Hair samples were washed with n-heptane, and then cut finely into small pieces. All samples were subjected to clean-up by HS-SPME and then GC PCI-MS/MS for analysis of FAEEs. Comparison of FAEE concentrations between treated and untreated hair showed in some instances that application of hair spray or wax products caused an increase in FAEE levels. Products containing alcohol caused a more substantial increase in alcohol metabolite concentrations in hair when compared to alcohol free products. Three volunteers using an alcohol based hairspray in the study experienced a significant increase in FAEE levels (+27.4%, +205.5%, and +1287.5%), with one of the volunteers showing levels below the cut off for ‘abstinence’ in the untreated scalp portion, and levels above the cut off for ‘chronic excessive consumption’ in the treated scalp portion. Performance evaluation of ethyl palmitate as sole marker, compared to the sum of four esters approach suggested that the two quantification approaches react in a very similar manner to the application of hair sprays and waxes. We would suggest that the interpretative value of FAEE hair measurements from people reporting the use of alcohol based hairsprays are treated with caution.

      PubDate: 2017-12-12T14:16:41Z
       
  • Automatic estimation of a scale resolution in forensic images
    • Abstract: Publication date: Available online 11 December 2017
      Source:Forensic Science International
      Author(s): I. Gertsovich, M. Nilsson, J.S. Bartůněk, I. Claesson
      This paper proposes a new method for an automatic detection of a resolution of a scale or a ruler with graduation marks in the shoeprint images. The method creates a vector of the correlations estimated from the co-occurrence matrices for every row in a shoeprint image. The scale resolution is estimated from maxima in Fourier spectrum of the correlations’ vectors. The proposed method is evaluated on over 500 images taken at crime scenes and in a forensics laboratory. The experimental results indicate the possibility of applying the proposed method to automatically estimate the scale resolution in forensic images. The automatic detection of a scale resolution could be used to automatically rescale a forensic image before the printing this image in ”one-to-one” scale. Furthermore, the proposed method could be used to automatically rescale images to an equal scale thus allowing to compare the images digitally.

      PubDate: 2017-12-12T14:16:41Z
       
  • Detection of copy-move image modification using JPEG compression
           model
    • Abstract: Publication date: Available online 9 December 2017
      Source:Forensic Science International
      Author(s): Adam Novozámský, Michal Šorel
      The so-called copy-move forgery, based on copying an object and pasting in another location of the same image, is a common way to manipulate image content. In this paper, we address the problem of copy-move forgery detection in JPEG images. The main problem with JPEG compression is that the same pixels, after moving to a different position and storing in the JPEG format, have different values. The majority of existing algorithms is based on matching pairs of similar patches, which generates many false matches. In many cases they cannot be eliminated by postprocessing, causing the failure of detection. To overcome this problem, we derive a JPEG-based constraint that any pair of patches must satisfy to be considered a valid candidate and propose an efficient algorithm to verify the constraint. The constraint can be integrated into most existing methods. Experiments show significant improvement of detection, especially for difficult cases, such as small objects, objects covered by textureless areas and repeated patterns.

      PubDate: 2017-12-12T14:16:41Z
       
  • MDPV in forensic routine cases: Psychotic and aggressive behavior in
           relation to plasma concentrations
    • Abstract: Publication date: Available online 8 December 2017
      Source:Forensic Science International
      Author(s): Marco Diestelmann, Anna Zangl, Inge Herrle, Eva Koch, Matthias Graw, Liane D. Paul
      The new psychoactive substance 3,4-methylenedioxypyrovalerone (MDPV) belongs to the group of synthetic cathinones and is purchased mainly as “research chemical” or “bath salt” on the illegal drug market, also in South Bavaria. MDPV was detected in blood and urine samples from 2010 on in 50 authentic routine cases in a forensic setting. Plasma concentrations in 46 cases with available blood specimens ranged from approximately 1.0 to 301μg/L (median 23.7; mean 47.9μg/L), detected by a fully validated LC-MS/MS method. Subjects aged between 16 and 54 years (median 36; mean 35 years) and reflected experienced chronic drug users. Accused offences were mainly violent crimes such as bodily harm, robberies, homicides and acts of resistance. A lot of subjects showed highly aggressive and violent behavior with endangerment of self and others and/or psychotic symptoms as confusion, hallucinations or paranoia. The risk for such behavior rises with MDPV plasma concentrations above as low as 30μg/L, whereby a time interval of 1.5hours on average between incident and/or observation of impairment and blood sampling has to be taken into account. Comprehensive toxicological analysis proved poly-drug use in almost all cases including opiates/opioids, benzodiazepines and other sedatives, antidepressants and other stimulants, also other new psychoactive substances. Alcohol was detected only in three cases. Co-consumed benzodiazepines seem not be able to completely prevent psychotic effects despite their use as first-line treatment for patients with synthetic cathinone poisonings. The study demonstrates that relatively low plasma concentrations of MDPV could be associated with mental impairment which is relevant in the assessment of forensic cases.

      PubDate: 2017-12-12T14:16:41Z
       
  • Stability of postmortem methemoglobin: artifactual changes caused by
           storage conditions
    • Abstract: Publication date: Available online 8 December 2017
      Source:Forensic Science International
      Author(s): Vincent Varlet, Elenore Ryser, Marc Augsburger, Cristian Palmiere
      Hemoglobin is the protein in red blood cells that carries and distributes oxygen to the body. Methemoglobinemia is a blood disorder in which an abnormal amount of methemoglobin (MetHb), a form of hemoglobin (Hb), is produced from either inadequate MetHb reductase activity or too much MetHb production or by exposure to oxidizing agents. This could lead to anoxia and death if it is not treated. However, this parameter has not been investigated as a valid post-mortem indicator because random MetHb levels have been observed in various studies: MetHb increases can be observed due to autoxidation during storage, and MetHb decreases can be observed due to MetHb reductase or microbial activity in post-mortem samples. MetHb variations can also come from the blood state and can interfere in the optical measurements of MetHb. We have studied the post-mortem MetHb concentrations according to various storage conditions. Based on our results, both the post-mortem delay and the delay before analysis should be reduced whenever possible to avoid changes in MetHb. If the analysis is delayed for a short period of time (two weeks), the blood sample taken at autopsy should not be frozen but collected in EDTA preservative and stored under refrigeration (4–6°C) until analysis. If the analysis is delayed for a longer period (more than two weeks), the blood sample should be frozen with cryoprotectant at −80°C or −196°C.

      PubDate: 2017-12-12T14:16:41Z
       
  • Visualization of old bruises in children: Use of violet light to record
           long-term bruises
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Sohtaro Mimasaka, Toru Oshima, Maki Ohtani
      When a child consultation center evaluates abused children, evidence of the abuse must be documented. Children who have suffered physical abuse often have bruises, which cannot be confirmed by visualization when the bruise has healed. In forensics, a method to confirm an old bruise by ultraviolet radiation is possible. However, long-term ultraviolet exposure can be harmful. In this study, we observed 15 bruises on healthy volunteer children using four kinds of light sources, including ultraviolet radiation, over time. The violet light source enabled observation of a bruise for a longer time than ultraviolet radiation. Although other studies have shown that violet light is superior for enhancing bruises, this is the first report to evaluate data concerning the ability to identify bruises over time in living children. These results might help to identify evidence of past violence suffered by children.

      PubDate: 2017-11-27T19:29:21Z
       
  • Multi-spectral imaging for the estimation of shooting distances
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Félix Zapata, María López-López, José Manuel Amigo, Carmen García-Ruiz
      Multispectral images of clothing targets shot at seven different distances (from 10 to 220cm) were recorded at 18 specific wavelengths in the 400–1000nm range to visualize the gunshot residue (GSR) pattern. Principal component analysis (PCA) showed that the use of violet-blue wavelengths (430, 450 and 470nm) provided the largest contrast between the GSR particles and the white cotton fabric. Then, the correlation between the amount of GSR particles on clothing targets and the shooting distance was studied. By selecting the blue frame of multispectral images (i.e. the blue frame in the red-green-blue (RGB) system which falls at 470nm), the amount of pixels containing GSR particles was accounted based on the intensity of pixels in that frame. Results demonstrated that the number of pixels containing GSR exponentially decreases with the shooting distance from 30 to 220cm following a particular exponential equation. However, the targets shot at the shortest distance (10cm) did not satisfy the above equation, probably due to the noticeable differences of the GSR-pattern of these targets (e.g. high presence of soot). Then, the equation was applied to validation samples to estimate the shooting distances, obtaining results with an error below 10%.
      Graphical abstract image

      PubDate: 2017-11-27T19:29:21Z
       
  • Comparison and evaluation of the quick purification methods of
           methamphetamine hydrochloride from dimethyl sulfone for spectroscopic
           identification
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Hiroki Segawa, Kento Kumisaka, Ritsuko Sugita, Yuko T. Iwata, Tadashi Yamamuro, Kenji Kuwayama, Kenji Tsujikawa, Tatsuyuki Kanamori, Hiroyuki Inoue
      Methods to quickly purify methamphetamine hydrochloride from the cutting agent dimethyl sulfone for subsequent identification of confiscated crystalline samples using infrared absorption spectroscopy were compared and evaluated. Although sequential solvation and reprecipitation methods were simple, spectral contamination from dimethyl sulfone was inevitable and might affect the interpretation of the spectra. In addition, methamphetamine hydrochloride and dimethyl sulfone could form a solid solution because of solvation of both crystals into a single solution layer. By contrast, sublimation was an effective method for separation of methamphetamine hydrochloride and dimethyl sulfone. Sublimation combined with infrared absorption spectroscopy enabled rapid identification of crystalline methamphetamine hydrochloride.
      Graphical abstract image

      PubDate: 2017-11-27T19:29:21Z
       
  • Ankle fracture — Correlation of Lauge-Hansen classification and patient
           reported fracture mechanism
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Andrzej Boszczyk, Marcin Fudalej, Sławomir Kwapisz, Urszula Klimek, Marta Maksymowicz, Bartłomiej Kordasiewicz, Stefan Rammelt
      Introduction The genetic Lauge-Hansen classification is used for reconstruction of the mechanism of ankle injury. In this study, we addressed the question of agreement between the mechanism of the fracture as postulated by the Lauge-Hansen classification and mechanism reported by the patient in rotational ankle fractures. Material and methods Radiographs of 78 patients with acute malleolar fractures were analyzed and compared with fracture mechanisms reported by these patients. Results The patient reported mechanisms were in concordance with the mechanism deducted from the X-rays in 49% of cases. Only 17% of patients who recalled a pronation trauma actually had radiographs classified as pronation fractures while 76% of patients who recalled a supination trauma were also radiographically classified as having sustained supination type fractures. Conclusion The Lauge-Hansen classification should be used with caution for determining the actual mechanism of injury as it was able to predict the patient reported fracture mechanism in less than 50% of cases. A substantial percentage of fractures appearing radiographically as supination type injuries may have been actually produced by a pronation fracture mechanism.

      PubDate: 2017-11-27T19:29:21Z
       
  • Assessment of signature handwriting evidence via score-based likelihood
           ratio based on comparative measurement of relevant dynamic features
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Xiao-hong Chen, Christophe Champod, Xu Yang, Shao-pei Shi, Yi-wen Luo, Nan Wang, Ya-chen Wang, Qi-meng Lu
      This paper extends on previous research on the extraction and statistical analysis on relevant dynamic features (width, grayscale and radian combined with writing sequence information) in forensic handwriting examinations. In this paper, a larger signature database was gathered, including genuine signatures, freehand imitation signatures, random forgeries and tracing imitation signatures, which are often encountered in casework. After applying Principle Component Analysis (PCA) of the variables describing the proximity between specimens, a two-dimensional kernel density estimation was used to describe the variability of within-genuine comparisons and genuine–forgery comparisons. We show that the overlap between the within-genuine comparisons and the genuine–forgery comparisons depends on the imitated writer and on the forger as well. Then, in order to simulate casework conditions, cases were simulated by random sampling based on the collected signature dataset. Three-dimensional normal density estimation was used to estimate the numerator and denominator probability distribution used to compute a likelihood ratio (LR). The comparisons between the performance of the systems in SigComp2011 (based on static features) and the method presented in this paper (based on relevant dynamic features) showed that relevant dynamic features are better than static features in terms of accuracy, false acceptance rate, false rejection rate and calibration of likelihood ratios.
      Graphical abstract image

      PubDate: 2017-11-27T19:29:21Z
       
  • Individual human scent as a forensic identifier using mantrailing
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Leif Woidtke, Jan Dreßler, Carsten Babian
      Specially trained dogs have long been used by law enforcement agencies to help in criminal investigations and in searching for missing persons. Still, it is unclear which components of human scent released into the environment contribute to successful searches of individuals. In this study, saliva and axillary sweat samples were taken from a total of 190 people. Additionally, DNA was extracted from whole blood of seven different people and used as an odour sample as well. Overall 675 tests (trails) were performed during a period of 18 months. The ability to track individuals with the odour samples mentioned above was examined with seven dogs, four of which were specially-trained dogs (mantrailer) from the Saxony Police. Results indicated that specially-trained police dogs can track a person with an average success rate of 82% and correctly identify the absence of an odour track with an average success rate of 97% under various conditions. Private rescue dogs were less successful with an average success rate of 65% and 75% respectively. These data suggest that the potential error rate of a well-trained handler team is low and can be a useful tool for law enforcement personnel. Saliva, as a reference odour source, was found to be particularly suitable for the search. The results of the study suggest that the components contained in axillary sweat, saliva and DNA extracted from whole blood are sufficient, serving as a key stimulus for individualized searches.

      PubDate: 2017-11-27T19:29:21Z
       
  • Unintentional mortality associated with paracetamol and codeine
           preparations, with and without doxylamine, in Australia
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Ria E. Hopkins, Malcolm Dobbin, Jennifer L. Pilgrim
      Introduction Misuse of paracetamol, codeine and doxylamine combination analgesics may lead to addiction and mortality. This study aimed to (1) identify unintentional deaths in Australia associated with use of combination analgesic products containing paracetamol, codeine and doxylamine; (2) describe cases characteristics, including demographics and additional medication use; and (3) identify common factors associated with misuse and mortality of these medicines in Australia. Design This retrospective case series analysed National Coronial Information System data to identify cases of unintentional death attributable to paracetamol, codeine and doxylamine products between 2002 and 2012. Setting Three Eastern Australian states: New South Wales, Queensland, Victoria, comprising a population of approximately 18.6 million people. Results 441 unintentional deaths attributed to paracetamol/codeine products were identified; doxylamine was detected in 102 cases (23%). Overall unintentional death rates rose from 0.9-per-million in 2002 to 3.6-per-million in 2009, declining to 1.9-per-million in 2012. Median age at time of death was 48, half of all cases occurred between 35-54 years of age, and 57% were female. Concomitant medication use was detected in 79% of cases, including benzodiazepines, other opioids, psychiatric medications, alcohol and illicit drugs. Behaviours consistent with drug misuse including doctor/pharmacy shopping, excessive dosages and extended use, were identified in 24% of cases. Conclusions This study identified 441 deaths associated with codeine-combination analgesic products across three Australian states; with an average of 40 deaths per year. Death commonly involved multiple substance use and abuse behaviours indicative of misuse and dependence.

      PubDate: 2017-11-27T19:29:21Z
       
  • Cranial trauma in handgun executions: Experimental Data Using Polyurethane
           Proxies
    • Abstract: Publication date: Available online 27 November 2017
      Source:Forensic Science International
      Author(s): Seth Taylor, Elena F. Kranioti
      Gun violence is a global phenomenon with regional variation in frequency and severity. Handguns are often used in violent deaths such as suicides and homicides. Hence, ballistic trauma is a critical subject of forensic investigations. Trauma patterns are fundamental evidence for the reconstruction of the incident and for the determination of the manner of death. This study investigated the differences in trauma patterns with a series of experiments using six different calibers (.22 LR, .38 Special, .380 ACP, 9×19mm, .40 S&W, and .45 ACP) and four different bullet types. Synbone® spheres (polyurethane bone proxies) were used for close range 30centimeter (cm) simulated executions. The polyurethane spheres constitute an excellent proxy for human crania at the macroscopic level as suggested by other studies. The results showed that the radius of the entrance wound is positively correlated (Pearson’s correlation coefficient R=0.846, p <0.05) with the caliber dimension. As muzzle velocity increased, endocranial beveling increased. Bullet weight, conversely, does not seem to have an effect on the size of the endocranial beveling present in Synbone® spheres. The ballistic experiments exhibited similarities in entrance wound morphology; radial and concentric fracture patterns, hydraulic burst effect, circumferential delamination, and endocranial beveling with that of documented forensic cases with corresponding caliber shot. Synbone spheres seem appropriate for ballistic simulations of cranial injuries; yet, more research is needed to verify these observations.

      PubDate: 2017-11-27T19:29:21Z
       
  • Using handwriting to infer a writer’s country of origin for forensic
           intelligence purposes
    • Abstract: Publication date: Available online 24 November 2017
      Source:Forensic Science International
      Author(s): Anna Agius, Marie Morelato, Sébastien Moret, Scott Chadwick, Kylie Jones, Rochelle Epple, James Brown, Claude Roux
      Forensic science has traditionally focused the majority of its resources and objectives towards addressing Court-related questions. However, this view restricts the contribution of forensic science to one process and results in a loss of information as the investigative and intelligence roles are largely neglected. A change of perspective and expansion of the contributions of forensic science is required to take advantage of the benefits of abductive and inductive thought processes at the initial stages of the investigation. A forensic science discipline suffering from this imbalance is handwriting examination, which may be characterised as a time consuming and subjective process that is mostly carried out towards the end of the investigation for the purpose of judicial proceedings. Individual and habitual characteristics are the major handwriting features exploited, however alternate information concerning the author’s native language could potentially be used as a key element in an intelligence framework. This research focussed on the detection of characteristics that differentiate Vietnamese and English Australian writers based on their English handwriting. The study began with the extraction of handwriting characteristics from the writing of people from the two populations. The data was analysed using a logistic regression model and a classification and regression tree (CRT). Each recognised four class characteristics that were capable of distinguishing between the two nationalities. The logistic regression and CRT models were both capable of correctly predicting 93% of cases. Their predictive capabilities were then tested and supported using blind exemplars in order to mirror casework settings. It appeared that when using their respective class characteristics, the two models were capable of differentiating English Australians from Vietnamese in the data set. This proof of concept research demonstrated the plausibility of exploiting this additional information from a handwriting trace and taking advantage of it in an intelligence-led framework.

      PubDate: 2017-11-27T19:29:21Z
       
  • Combining Benford’s Law and machine learning to detect money laundering.
           An actual Spanish court case
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Elena Badal-Valero, José A. Alvarez-Jareño, Jose M. Pavía
      Objectives This paper is based on the analysis of the database of operations from a macro-case on money laundering orchestrated between a core company and a group of its suppliers, 26 of which had already been identified by the police as fraudulent companies. In the face of a well-founded suspicion that more companies have perpetrated criminal acts and in order to make better use of what are very limited police resources, we aim to construct a tool to detect money laundering criminals. Methods We combine Benford’s Law and machine learning algorithms (logistic regression, decision trees, neural networks, and random forests) to find patterns of money laundering criminals in the context of a real Spanish court case. Results After mapping each supplier’s set of accounting data into a 21-dimensional space using Benford’s Law and applying machine learning algorithms, additional companies that could merit further scrutiny are flagged up. Conclusions A new tool to detect money laundering criminals is proposed in this paper. The tool is tested in the context of a real case.

      PubDate: 2017-11-16T11:20:53Z
       
  • Simultaneous drug identification in urine of sexual assault victims by
           using liquid chromatography tandem mass spectrometry
    • Abstract: Publication date: January 2018
      Source:Forensic Science International, Volume 282
      Author(s): Hei Hwa Lee, Suen Chi Chen, Jong Feng Lee, Hsin Yu Lin, Bai Hsiun Chen
      According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid–liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

      PubDate: 2017-11-16T11:20:53Z
       
  • The correlation between concentrations of zolpidem and benzodiazepines in
           segmental hair samples and use patterns
    • Abstract: Publication date: Available online 7 November 2017
      Source:Forensic Science International
      Author(s): Hyojeong Kim, Sangeun Lee, Sanghwan In, Meejung Park, Sungnam Cho, Junguk Shin, Hunjoo Lee, Eunyoung Han
      The aim of this study was to investigate the correlation between histories of zolpidem and benzodiazepines use and their concentrations in hair as determined by segmental hair analysis, that is, by analyzing hair samples taken 0-1, 1-2, 2-3, 3-4, 4-5, and 5–6cm etc. and 0–3cm from the scalp, and whole hair. Of the 23 hair samples examined, 18 were collected from patients in a rehabilitation program and five were from patients that had taken zolpidem only once by prescription. All 23 patients provided written informed consent after reviewing the research plan, described their zolpidem and benzodiazepines use histories accurately, and provided hair samples, which were weighed, washed, cut into lengths of <1mm, and extracted in 100% methanol for 16h (diazepam-d5 was used as an internal standard). Extracts were evaporated under reduced pressure and reconstituted with aqueous methanol (1:1v/v). These extracts (10μL) were analyzed by Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS). The method used was validated by determining LOD, LOQ, calibration curves, intra- and inter-accuracies, precisions, matrix effects, process efficiencies, extraction efficiencies, and processed sample stabilities. Five hundred and ninety-five 1cm hair segments showed 61.59% positive probability and 86.71% negative probability of quality correlation between zolpidem and benzodiazepines use and concentrations in hair. Good qualitative correlations were observed between drug use and detection in hair. False positivity and false negativity were very low. Of the hair samples taken from patients in a rehabilitation program, subject nos. 4, 5, and 12 had correlation coefficients of 0.68, 0.54 and 0.71, respectively, for relationships between zolpidem use and concentration of zolpidem in hair. For the 5 patients taking only a single dose of zolpidem (10mg), the average zolpidem concentrations in hair were 20, 15 and 40pg/mg after 5, 30 and 60 days, respectively. This study shows a relationship between history of zolpidem and benzodiazepines use and their concentrations in 1cm hair segment.

      PubDate: 2017-11-10T12:41:06Z
       
  • Investigation of various factors influencing Raman spectra interpretation
           with the use of likelihood ratio approach
    • Abstract: Publication date: Available online 3 November 2017
      Source:Forensic Science International
      Author(s): Aleksandra Michalska, Agnieszka Martyna, Grzegorz Zadora
      The main aim of this study was to verify whether selected analytical parameters may affect solving the comparison problem of Raman spectra with the use of the likelihood ratio (LR) approach. Firstly the LR methodologies developed for Raman spectra of blue automotive paints obtained with the use of 785nm laser source (results published by the authors previously) were implemented for good quality spectra recorded for these paints with the use of 514.5nm laser source. For LR models construction two types of variables were used i.e. areas under selected pigments bands and coefficients derived from discrete wavelet transform procedure (DWT). Few experiments were designed for 785nm and 514.5nm Raman spectra databases after constructing well performing LR models (low rates of false positive and false negative answers and acceptable results of empirical cross entropy approach). In order to verify whether objective magnification described by its numerical aperture affects spectra interpretation, three objective magnifications − 20×(N.A=0.4), 50×(N.A=0.75) and 100×(N.A=0.85) within each of the applied laser sources (514.5nm and 785nm) were tested for a group of blue solid and metallic automotive paints having the same sets of pigments depending on the applied laser source. The findings obtained by two types of LR models indicate the importance of this parameter for solving the comparison problem of both solid and metallic automotive paints regardless of the laser source used for measuring Raman signal. Hence, the same objective magnification, preferably 50×(established based on the analysis of within- and between-samples variability and F-factor value), should be used when focusing the laser on samples during Raman measurements. Then the influence of parameters (laser power and time of irradiation) of one of the recommended fluorescence suppression techniques, namely photobleaching, was under investigation. Analysis performed on a group of solid automotive paint samples showed that time of irradiation upon established laser power does not affect solving the comparison problem with the use of LR test. Likewise upon established time of irradiation 5% or 10% laser power could be used interchangeably without changing conclusions within this problem. However, upon the established time of irradiation changes in laser power between control and recovered sample from 5% or 10% to 50% may cause erroneous conclusions. Additionally it was also proved that prolonged irradiation of paint does not quantitatively affect pigments bands areas revealed after such a pre-treatment.
      Graphical abstract image

      PubDate: 2017-11-10T12:41:06Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.227.104.40
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016