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191.
Wood M Laloup M Ramirez Fernandez Mdel M Jenkins KM Young MS Ramaekers JG De Boeck G Samyn N 《Forensic science international》2005,150(2-3):227-238
We present a validated method for the simultaneous analysis of basic drugs which comprises a sample clean-up step, using mixed-mode solid-phase extraction (SPE), followed by LC-MS/MS analysis. Deuterated analogues for all of the analytes of interest were used for quantitation. The applied HPLC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions for the non-deuterated analogues. Oral fluid was collected with the Intercept, a FDA approved sampling device that is used on a large scale in the US for workplace drug testing. However, this collection system contains some ingredients (stabilizers and preservatives) that can cause substantial interferences, e.g. ion suppression or enhancement during LC-MS/MS analysis, in the absence of suitable sample pre-treatment. The use of the SPE was demonstrated to be highly effective and led to significant decreases in the interferences. Extraction was found to be both reproducible and efficient with recoveries >76% for all of the analytes. Furthermore, the processed samples were demonstrated to be stable for 48 h, except for cocaine and benzoylecgonine, where a slight negative trend was observed, but did not compromise the quantitation. In all cases the method was linear over the range investigated (2-200 microg/L) with an excellent intra-assay and inter-assay precision (coefficients of variation <10% in most cases) for QC samples spiked at a concentration of 4, 12 and 100 microg/L. Limits of quantitation were estimated to be at 2 microg/L with limits of detection ranging from 0.2 to 0.5 microg/L, which meets the requirements of SAMHSA for oral fluid testing in the workplace. The method was subsequently applied to the analysis of Intercept samples collected at the roadside by the police, and to determine MDMA and MDA levels in oral fluid samples from a controlled study. 相似文献
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The importance of identification using the frontal sinus has been previously demonstrated in case reports. In this study, 39 cases of identification using frontal sinus comparison from the Ontario Chief Coroner's Office were reviewed and differences between antemortem and postmortem radiographs examined. All cases involved decedents older than twenty years. Three cases were rejected due to poor antemortem and postmortem film quality. One subject had no frontal sinus. Thirty-five cases provided conclusive postmortem to antemortem pattern matches. Sixteen cases also yielded metric (quantitative) matches. Duration between antemortem and postmortem radiographic examinations, age, gender, and cause of death did not affect the ability to obtain a match. This is the largest study undertaken on actual cases and demonstrates the validity of frontal sinus pattern matching for forensic identification. 相似文献
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Susanne Wood 《The Political quarterly》1974,45(2):251-251
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The changing role of tutorials and tutors in an age of mass higher education is sketched. The differing purposes of small group teaching are explored; small groups are shown to have a variety of academic and pastoral functions. The mechanics of tutorial organisation are explored and the range of teaching formats examined. 相似文献
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In this paper we develop a model to examine the extent to which bureaucrats are maximizing their own utility. In the spirit of Williamson (1964) and Simon (1957), we assume that bureaucrats are utility maximizers but not necessarily cost minimizers and we investigate how well the bureaucrat is doing in relation to his own goals. First, we hypothesize a utility function for the bureaucrat — we assume that the bureaucrat gains utility from producing municipal services as well as from hiring additional labor and capital. Then, using the concept of money metric utility, we determine the minimum expenditure necessary to achieve the same level of utility actually observed. Secondly, we determine the bureaucrat's distance from the utility maximizing choice of resources for a given level of expenditure. Finally, using a sample of public sector bureaucrats we attempt to explain the variation in wasted expenditure across municipalities and why bureaucrats might be underutilizers of each input relative to their own utility maximizing point. 相似文献