Trends in explosive contamination

This study sought to assign a rough order of magnitude for the amount of explosive residue likely to be available in real-world searches for clandestine explosives. A variety of explosives (TNT, TATP, HMX, AN, RDX, PETN) in various forms (powder, flake, detonating cord, plastic) were carefully weighed or cut into containers, and the amount of residue inadvertently remaining on the work area, hands, or containers was quantified. This was used to evaluate the spillage potential of each explosive. The adhesion of each explosive to a glass surface was quantified from amount of explosive adhering to the inside of a glass vial into which the explosive had been placed and then removed by vigorous tapping. In powdered form, most of the explosives--TNT, PETN, RDX, HMX, and TATP--exhibited similar spillage and adhesion to glass. However, PETN as sheet explosive and plasticized RDX (C-4), showed very little potential to contaminate surfaces, either by spillage or adhesion to glass.     

The forensic analysis of thermal transfer printing

Thermal transfer printing refers to printing processes that utilize heat to produce an image by either physical or chemical means or by a combination of both. As the technology has improved and the supplies have become less expensive, the use of thermal printing in the personal and business markets has increased significantly. Specifically, dye diffusion thermal transfer and thermal mass transfer have become predominant in the production of counterfeit credit cards, drivers' licenses, and other types of documents produced on plastic media. Chemical analysis by means of thin layer chromatography (TLC) has proven to be useful in characterizing various types of inks (e.g., writing and inkjet inks). In this study, the authors examined 81 different samples that included a total of 54 printer samples (43 photographic prints on paper and eleven plastic card samples) and 27 printer ribbons. A new TLC method was developed and tested utilizing a solvent system (80% n-hexane, 3% methyl ethyl ketone, and 17% ethyl acetate) that is capable of producing excellent resolution.     

Measures of aggression and mood changes in male weightlifters with and without androgenic anabolic steroid use

Supraphysiologic doses of testosterone are associated with increased aggression that is hypothesized to be a function of testosterone serum concentrations, mood, and personality. The study attempted to characterize this relationship among weightlifters who were users (n = 10) and nonusers (n = 18) of anabolic steroids. Participants were interviewed using the Modified Mania Rating Scale and Hamilton Rating Scale for Depression to assess mood, the Buss-Durkee Hostility Inventory (BDHI) and Point Subtraction Aggression Paradigm (PSAP) to assess aggression, and the Personality Disorder Questionnaire (PDQ-R) to assess personality. Blood samples were obtained for the determination of total, free, and weakly bound testosterone. Comparisons of continuous variables between testosterone users and non-users were performed with a parametric (unpaired t-test) or non-parametric (Mann-Whitney) test where appropriate. Correlations with testosterone were examined separately for testosterone users and non-users, using Spearman rank correlation. The subjective (BDHI) and objective (PSAP) assessments of aggression found that supranormal testosterone concentrations were associated with increased aggression. However, the PDQ-R results suggest that this finding was confounded by the personality disorder profile of the steroid users, because steroid users demonstrated Cluster B personality disorder traits for antisocial, borderline, and histrionic personality disorder.     

Polydrug fatality involving metaxalone

A 29-year old female with a history of depression was found dead in a hotel room. The death scene investigation found empty pill bottles and an empty liter bottle of wine. Metaxalone, a centrally acting muscle relaxant, along with citalopram, ethanol, and chlorpheniramine were identified in the postmortem samples and quantitated by gas chromatography-mass spectrometry. The concentration of metaxalone in femoral vein blood was 39 mg/L. The heart blood concentration was 54 mg/L. Femoral vein blood concentrations of citalopram and chlorpheniramine were 0.77 mg/L and 0.04 mg/L, respectively. Ethanol levels were 0.13 g/dL in vitreous and 0.08 g/dL in heart blood. Other tissue samples were also analyzed. The authors consider the metaxalone concentrations toxic and potentially fatal. The citalopram concentrations were lower than those reported in fatal cases for this drug alone. Death was ascribed to polydrug abuse/overdose with metaxalone a major contributor. This represents the first reported case to our knowledge in which a metaxalone overdose significantly contributed to death.     

Characterization of surface organic components of human hair by on-line supercritical fluid extraction-gas chromatography/mass spectrometry: a feasibility study and comparison with human identification using mitochondrial DNA sequences

This paper discusses results of a supercritical fluid extraction-gas chromatography/mass spectrometry (SFE-GC/MS) study of small samples ( 100 microg to 1 mg) of human scalp hair. The method offers a number of benefits including greater sensitivity than liquid extraction methods because the entire extractable mass is transferred to the analytical system, compared with only a few percent from a conventional liquid extraction/injection. The project's goals were to determine if SFE-GC/MS analyses of the surface-extractable components of an individual's hair yield consistent chemical profiles and to investigate if the profiles are sufficiently different to distinguish them from those of other individuals. In addition, the mtDNA sequences from ten of the same individuals used in the SFE-GC/MS study from four family units were determined, and, while the families were distinguishable, the maternal relations yielded identical sequences. In tandem, SFE-GC/MS and mtDNA techniques may provide valuable complementary data from forensic hair samples.     

STR DNA typing: increased sensitivity and efficient sample consumption using reduced PCR reaction volumes

Improvements in detection limits/sensitivity and lower sample consumption are potential benefits of reducing PCR reaction volumes used in forensic DNA typing of crime scene samples. This premise was studied first with experimental mixtures and a nine-loci megaplex, which demonstrated stochiometric amplification and accurate detection. Next, adjudicated casework samples were subjected to amplification under 15 different template DNA to PCR reaction volume ratios. Reduction of PCR reaction volume and DNA down to 10 microL and 0.500 ng, respectively, produced identical profiles with the same signal intensity and heterozygous allele peak height ratio (HR). Reduction to 5 microL and 0.063 ng yielded HR values that were slightly affected in one to three STR loci. PCR reaction volume reduction can enhance detection and sensitivity while reducing the consumption of irreplaceable crime scene samples.     

Using Ecological Inference Point Estimates as Dependent Variables in Second-Stage Linear Regressions

The practice of using point estimates produced by the King ecologicalinference technique as dependent variables in second-stage linearregressions leads to second-stage results that, in general,are inconsistent. This conclusion holds even when all assumptionsbehind King's ecological technique are satisfied. Second-stageinconsistency is a consequence of the fact that King-based pointestimates of disaggregated quantities contain errors correlatedwith the true quantities the estimates measure. Our findingson second-stage inconsistency, as well as a fix that we propose,follow from econometric theory in conjunction with an analysisof simulated and real ecological data sets.