The congener profiles of polybrominated diphenyl ethers (PBDEs) in human and wildlife samples are dominated by brominated diphenyl ether (BDE) congeners 47, 99, 100, 153, and 154, all of which are components of the commercial pentaBDE mixtures commonly used in a variety of flammable consumer products. Very little information is available on the toxicokinetics of these congeners and no studies are available directly comparing these BDE congeners in mice. Therefore, the objective of this study was to compare the distribution, metabolism, and excretion of BDEs 47, 99, 100 and 153. Female C57BL/6 mice were administered a single dose of BDE (1 mg/kg: 2.1, 1.9, 1.9, and 1.8 mumol/kg, respectively) intravenously. Excretion was monitored daily, and terminal tissue disposition was examined 5 days following exposure. All BDE congeners in this study distribute with similar patterns into lipophilic tissues; however, tissue concentrations 5 days following exposure were much higher for BDE-153 than for 100, 99, and 47, respectively. Excretion rates were inversely related to tissue concentrations as BDE-47 was the most rapidly excreted congener, followed by BDE-99, -100, and -153. Differences in tissue concentrations were largely driven by congener-specific urinary elimination rates which were associated with protein binding in the urine. While the overall rate of metabolism appeared to be low, analysis of metabolites in daily feces samples revealed that BDE-99 was the most rapidly metabolized congener in this study. The results of this study demonstrate that congener substitution plays a role in the distribution, metabolism, and excretion of PBDEs in mice and it is therefore important to consider the differential toxicokinetic parameters associated with each congener when assessing the risk to human health from these PBDE congeners.
To compare different scoring algorithms for Pick-N multiple correct answer multiple-choice (MC) exams regarding test reliability, student performance, total item discrimination and item difficulty. Data from six 3rd year medical students' end of term exams in internal medicine from 2005 to 2008 at Munich University were analysed (1,255 students, 180 Pick-N items in total). Scoring Algorithms: Each question scored a maximum of one point. We compared: (a) Dichotomous scoring (DS): One point if all true and no wrong answers were chosen. (b) Partial credit algorithm 1 (PS(50)): One point for 100% true answers; 0.5 points for 50% or more true answers; zero points for less than 50% true answers. No point deduction for wrong choices. (c) Partial credit algorithm 2 (PS(1/m)): A fraction of one point depending on the total number of true answers was given for each correct answer identified. No point deduction for wrong choices. Application of partial crediting resulted in psychometric results superior to dichotomous scoring (DS). Algorithms examined resulted in similar psychometric data with PS(50) only slightly exceeding PS(1/m) in higher coefficients of reliability. The Pick-N MC format and its scoring using the PS(50) and PS(1/m) algorithms are suited for undergraduate medical examinations. Partial knowledge should be awarded in Pick-N MC exams.
BackgroundIn the past decades, various frameworks, methods, indicators, and tools have been developed to assess the needs as well as to monitor and evaluate (needs assessment, monitoring and evaluation; “NaME”) health research capacity development (HRCD) activities. This systematic review gives an overview on NaME activities at the individual and organizational level in the past 10 years with a specific focus on methods, tools and instruments. Insight from this review might support researchers and stakeholders in systemizing future efforts in the HRCD field.MethodsA systematic literature search was conducted in PubMed and Google Scholar. Additionally, the personal bibliographies of the authors were scanned. Two researchers independently reviewed the identified abstracts for inclusion according to previously defined eligibility criteria. The included articles were analysed with a focus on both different HRCD activities as well as NaME efforts.ResultsInitially, the search revealed 700 records in PubMed, two additional records in Google Scholar, and 10 abstracts from the personal bibliographies of the authors. Finally, 42 studies were included and analysed in depth. Findings show that the NaME efforts in the field of HRCD are as complex and manifold as the concept of HRCD itself. NaME is predominately focused on outcome evaluation and mainly refers to the individual and team levels.ConclusionA substantial need for a coherent and transparent taxonomy of HRCD activities to maximize the benefits of future studies in the field was identified. A coherent overview of the tools used to monitor and evaluate HRCD activities is provided to inform further research in the field.
BackgroundPrevious studies have shown medical students in Germany to have little interest in research while at the same time there is a lack of physician scientists. This study’s aim is to investigate factors influencing publication productivity of physicians during and after finishing their medical doctorate.MethodsWe conducted a PubMed search for physicians having received their doctoral degree at Ludwig-Maxmilians-University Munich Faculty of Medicine between 2011 and 2013 (N = 924) and identified the appropriate impact factor (IF) for each journal the participants had published in. Gender, age, final grade of the doctorate, participation in a structured doctoral study program and joint publication activities between graduate and academic supervisor were defined as factors. For analyses we used nonparametric procedures.ResultsMen show significantly more publications than women. Before their doctoral graduation men publish 1.98 (SD ± 3.64) articles on average, women 1.15 (±2.67) (p < 0.0001, d = 0.27). After completion of the doctorate (up to 06/2015), 40 % of men still publish, while only 24.3 % of women (p < 0.0001, φ = 0.17) continue to publish. No differences were found concerning the value of IFs. Similar results were found regarding the variable ‘participation in a structured doctoral study program’. Until doctoral graduation, program participants publish 2.82 (±5.41) articles, whereas participants doing their doctorate individually only publish 1.39 (±2.87) articles (p < 0.0001, d = 0.46). These differences persist in publication activities after graduation (45.5 vs. 29.7 %, p = 0.008, φ = 0.09). A structured doctorate seems to have positive influence on IFs (4.33 ± 2.91 vs. 3.37 ± 2.82, p = 0.006, d = 0.34). Further significant results concern the variables ‘final grade’ and ‘age’: An early doctoral graduation and an excellent or very good grade for the doctoral thesis positively influence publication productivity. Finally, joint publication activities between the graduate and his/her academic supervisor result in significantly higher IFs (3.64 ± 3.03 vs. 2.84 ± 2.25, p = 0.007, d = 0.28).ConclusionsThe study’s results support the assumption about women’s underrepresentation in science as well as the relevance of structured doctoral study programs for preparing and recruiting young academics in medicine for scientific careers. Promoting women and further development of structured doctoral study programs are highly recommended.
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