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Johnson D.J.,California State University, Los Angeles | Andersen C.,Scientific Services Bureau | Scriven K.A.,800 Paseo Rancho Castilla | Klein A.N.,OC Crime Laboratory | And 3 more authors.
Journal of Forensic Sciences | Year: 2014

Bloodstain pattern analysis to determine the wound-of-origin of bloodstains is problematic with nonspecific patterns. In this proof-of-concept study, the authors examined a molecular approach to correlate bloodstains with injuries using the rat as a model. Specifically, investigations were conducted on the rat brain marker, rno-miR-124-3p, with the QIAGEN miScript System and real-time PCR analysis. Rno-miR-124-3p was detected in brain homogenates diluted 100,000 in 3-week-old, room temperature stored, simulated brain-blood stains; and in bloodstains from head gunshot wounds collected with swabs and subsequently frozen for 9-18 months; however, rno-miR-124-3p was not detected in whole blood. Proof-of-principle was demonstrated by the ability to distinguish bloodstains from a gunshot wound to the head versus bloodstains from a gunshot wound to the chest, by the testing of otherwise identical bloodstains from the two patterns for the presence of the marker. The results suggest a viable approach to a longstanding problem in casework. © 2014 American Academy of Forensic Sciences. Source


Oostdik K.,Promega Corporation | Lenz K.,Promega Corporation | Nye J.,Michigan State Police | Schelling K.,Michigan State Police | And 26 more authors.
Forensic Science International: Genetics | Year: 2014

The original CODIS database based on 13 core STR loci has been overwhelmingly successful for matching suspects with evidence. Yet there remain situations that argue for inclusion of more loci and increased discrimination. The PowerPlex® Fusion System allows simultaneous amplification of the following loci: Amelogenin, D3S1358, D1S1656, D2S441, D10S1248, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D7S820, D5S818, TPOX, DYS391, D8S1179, D12S391, D19S433, FGA, and D22S1045. The comprehensive list of loci amplified by the system generates a profile compatible with databases based on either the expanded CODIS or European Standard Set (ESS) requirements. Developmental validation testing followed SWGDAM guidelines and demonstrated the quality and robustness of the PowerPlex® Fusion System across a number of variables. Consistent and high-quality results were compiled using data from 12 separate forensic and research laboratories. The results verify that the PowerPlex® Fusion System is a robust and reliable STR-typing multiplex suitable for human identification. © 2014 The Authors. Source


Nguyen Q.,800 Paseo Rancho Castilla | Mckinney J.,SALt Inc | Johnson D.J.,California State University, Los Angeles | Roberts K.A.,California State University, Los Angeles | And 2 more authors.
Journal of Forensic Sciences | Year: 2012

In this proof-of-concept study, high-resolution melt curve (HRMC) analysis was investigated as a postquantification screening tool to discriminate human CSF1PO and THO1 genotypes amplified with mini-STR primers in the presence of SYBR Green or LCGreen Plus dyes. A total of 12 CSF1PO and 11 HUMTHO1 genotypes were analyzed on the LightScanner HR96 and LS-32 systems and were correctly differentiated based upon their respective melt profiles. Short STR amplicon melt curves were affected by repeat number, and single-source and mixed DNA samples were additionally differentiated by the formation of heteroduplexes. Melting curves were shown to be unique and reproducible from DNA quantities ranging from 20 to 0.4ng and distinguished identical from nonidentical genotypes from DNA derived from different biological fluids and compromised samples. Thus, a method is described which can assess both the quantity and the possible probative value of samples without full genotyping. 2012 American Academy of Forensic Sciences. 2012 American Academy of Forensic Sciences. Published 2012. This article is a U.S. Government work and is in the public domain in the U.S.A. Source


McElrea A.,800 Paseo Rancho Castilla | Su C.,800 Paseo Rancho Castilla | Smith L.,800 Paseo Rancho Castilla
Journal of the Canadian Society of Forensic Science | Year: 2011

An intra-subject comparative study was performed using breath analysis to assess the forensic implications of data truncation on peak blood alcohol concentrations (Cmax). Accordingly, several other forensically relevant pharmacokinetic parameters associated with Cmax were investigated, including the time-to-peak (Tmax), plateau (PLAT) duration, and the rise in blood alcohol concentration (BAC) following the end of drinking (EOD). The study consisted of three drinking sessions, nine subjects per session, with drinking intervals of 30, 90, and 180 minutes, and ethanol doses of 1.0, 1.1, and 1.6 g/kg, respectively. Three-digit breath measurements were collected in duplicate at 10, 30, 45, 60, 75, 90, 105, 120, 135, 195, and 255 minutes following EOD using a fuel-cell based breath instrument (Intox ECIR®). Breath results were then computed using two different data treatment methods. The first method averaged duplicate three-digit breath measurements and reported results to the third digit. The second method used the lower of the two duplicate measurements and reported results to the truncated second digit. The results of the two data treatment methods were then compared using general statistics and alcohol concentration-time profiles. The overall rise in BAC following EOD for three-digit results was 0.009 g/210L with a range of 0.000-0.030 g/210L (standard deviation 0.008 g/210L). When breath measurements where truncated, 25 of the 27 subjects had a rise in BAC of 0.02 g/210L or less. In total, 6 subjects had no rise in BAC following the EOD when evaluating the three-digit results. In contrast, when BAC results were truncated, 11 subjects exhibited no increase in BAC following EOD. The overall Tmax was reduced from 41 minutes to 26 minutes, and overall PLAT durations were extended from 22 to 39 minutes, when the breath measurements were truncated. Source

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