Development of a harmonised method for the profiling of amphetamines VI: Evaluation of methods for comparison of amphetamine

Amphetamine samples were analysed by gas chromatography-mass spectrometry (GC-MS), and the peak areas of 33 target compounds were transformed by applying various pretreatment techniques. The objective was to optimise the ability of a number of distance metrics to establish links between samples of amphetamine originating from the same batch (henceforth referred to as linked distances). Furthermore, partial least squares discriminant analysis (PLS-DA) was used to evaluate the effects of various pretreatment methods on separation of amphetamine batches synthesised by the Leuckart reaction, reductive amination of benzyl methyl ketone, and the nitrostyrene route. The most efficient way to pretreat GC-MS data varied for the different distance metrics, although best results were obtained when data were normalised to the sum of peak areas, and either the fourth root or a logarithm was applied to the normalised data. When pretreating normalised data by fourth root transformation, Pearson correlation was the distance metric that was most successful at finding linked samples. Normalisation and the use of fourth root also represented the best method of pretreating data when employing PLS-DA to separate samples synthesised by different routes. To achieve a faster and more user-friendly procedure for evaluating chromatograms, experiments were performed in which the number of target compounds used to compare samples was reduced. The effect of each compound that was removed was studied by applying PLS-DA and by using Pearson correlation to calculate linked distances as well as unlinked distances (between samples from different batches of amphetamine). Considering both links between samples from the same batch and separation of samples synthesised by different routes, the best results were obtained with the data set comprising 26 compounds. Finally, it was found that the profiling method developed in this work was superior to an existing technique with respect to separating linked and unlinked distances.     

Schizophrenia, AIDS and the decision to prescribe HAART: results of a national survey of HIV clinicians

Individuals with schizophrenia are at risk of developing HIV and are known to experience barriers to optimal medical care. Our goal was to determine, among a cohort of HIV clinicians, whether or not the diagnosis of schizophrenia affected the clinical decision to offer highly active antiretroviral therapy (HAART) to AIDS patients. This is a cross-sectional study of a random, national sample of HIV experts drawn from the membership of the American Academy of HIV Medicine. Participants were mailed a self-administered questionnaire with a case vignette of a new onset AIDS patient and were specifically asked whether or not they would recommend HAART treatment. Vignettes were randomly assigned to include a diagnosis of schizophrenia or not. We located 649 clinicians (93%); 347 responded (53.4%). Responders and non-responders did not differ in demographics or work characteristics. Recommendation of antiretroviral treatment did not differ between those who received a case vignette with schizophrenia versus those who did not(95.8% vs. 96.6%, p=0.69). Compared to those who received a case vignette without schizophrenia, those who received vignettes with schizophrenia were more likely to avoid prescribing efavirenz, a medication with known neuropsychiatric side effects(17.7% vs. 45.5%, p < 0.01), more likely to agree to be helped by a specialist(34.5% vs. 12.9%, p < 0.01), and more likely to recommend directly observed therapy (20% vs.10%, p = 0.01). HIV clinicians recognize the importance of recommending HAART treatment to individuals with schizophrenia and AIDS and avoid using antiretroviral medication with known neuropsychiatric side effects.     

Retrospective and Prospective Performance Assessments during the 2004 Election Campaign: Tests of Mediation and News Media Priming

According to many theoretical accounts of the vote choice, distal determinants (e.g., party identification) influence proximal determinants (e.g., perceptions of candidates), which in turn shape candidate preferences. Yet almost no research on voting has formally tested such mediational hypotheses. Using national survey data collected between February and September of 2004, this paper begins by illustrating how to conduct such investigations. We explored whether public approval of President Bush’s handling of a series of specific national problems (e.g., the Iraq war) influenced overall assessments of his job performance and evaluations of his likely future performance versus John Kerry’s, which in turn shaped vote choices. The results are consistent with the claim of mediation and shed additional light on the impact of various issues on the 2004 election outcome. We also tested what we term the “dosage hypothesis,” derived from news media priming theory, which posits that changes in the amount of media coverage of an issue during the course of a campaign should precipitate changes in the weight citizens place on that issue when evaluating the president’s overall job performance, particularly among citizens most exposed to the news. Surprisingly, this analysis did not yield consistent support for the venerable dosage hypothesis, suggesting that the conditions under which priming occurs should be specified much more precisely in future work.

Characterization of the triacylglycerol crystal formation in adipose tissue during a vehicle collision

The unusual appearance of crystalline fat structures was observed during the postmortem examination of a motor vehicle accident victim. The crystal structures were characterized using Fourier transform infrared spectroscopy and x-ray diffractometry. The structures were found to be made of triacylglycerols, a dominant lipid structure found in human adipose tissue, capable of forming various polymorphic structures. The morphology of the crystalline material was found using both techniques to be predominantly the beta' form of triacylglycerols. The accelerated growth of such triacylglycerol morphology has been observed as a result of shear stresses in other studies involving edible fats. As a result of the findings of this study, it is proposed that increased shear forces may be responsible for the formation of the unusual fat structure found in the victim. An understanding of the effect of forces on the structure of body fat in high-impact collisions can potentially assist in verifying a high-velocity impact.