164 research outputs found

    Graduates from a traditional medical curriculum evaluate the effectiveness of their medical curriculum through interviews

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    <p>Abstract</p> <p>Background</p> <p>In 1996 The University of Liverpool reformed its medical course from a traditional lecture-based course to an integrated PBL curriculum. A project has been underway since 2000 to evaluate this change. Part of this project has involved gathering retrospective views on the relevance of both types of undergraduate education according to graduates. This paper focuses on the views of traditional Liverpool graduates approximately 6 years after graduation.</p> <p>Methods</p> <p>From February 2006 to June 2006 interviews took place with 46 graduates from the last 2 cohorts to graduate from the traditional Liverpool curriculum.</p> <p>Results</p> <p>The graduates were generally happy with their undergraduate education although they did feel there were some flaws in their curriculum. They felt they had picked up good history and examination skills and were content with their exposure to different specialties on clinical attachments. They were also pleased with their basic science teaching as preparation for postgraduate exams, however many complained about the overload and irrelevance of many lectures in the early years of their course, particular in biochemistry. There were many different views about how they integrated this science teaching into understanding disease processes and many didn't feel it was made relevant to them at the time they learned it. Retrospectively, they felt that they hadn't been clinically well prepared for the role of working as junior doctor, particularly the practical aspects of the job nor had enough exposure to research skills. Although there was little communication skills training in their course they didn't feel they would have benefited from this training as they managed to pick up had the required skills on clinical attachments.</p> <p>Conclusion</p> <p>These interviews offer a historical snapshot of the views of graduates from a traditional course before many courses were reformed. There was some conflict in the interviews about the doctors enjoying their undergraduate education but then saying that they didn't feel they received good preparation for working as a junior doctor. Although the graduates were happy with their undergraduate education these interviews do highlight some of the reasons why the traditional curriculum was reformed at Liverpool.</p

    Views of junior doctors about whether their medical school prepared them well for work: questionnaire surveys

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    <p>Abstract</p> <p>Background</p> <p>The transition from medical student to junior doctor in postgraduate training is a critical stage in career progression. We report junior doctors' views about the extent to which their medical school prepared them for their work in clinical practice.</p> <p>Methods</p> <p>Postal questionnaires were used to survey the medical graduates of 1999, 2000, 2002 and 2005, from all UK medical schools, one year after graduation, and graduates of 2000, 2002 and 2005 three years after graduation. Summary statistics, chi-squared tests, and binary logistic regression were used to analyse the results. The main outcome measure was the level of agreement that medical school had prepared the responder well for work.</p> <p>Results</p> <p>Response rate was 63.7% (11610/18216) in year one and 60.2% (8427/13997) in year three. One year after graduation, 36.3% (95% CI: 34.6, 38.0) of 1999/2000 graduates, 50.3% (48.5, 52.2) of 2002 graduates, and 58.2% (56.5, 59.9) of 2005 graduates agreed their medical school had prepared them well. Conversely, in year three agreement fell from 48.9% (47.1, 50.7) to 38.0% (36.0, 40.0) to 28.0% (26.2, 29.7). Combining cohorts at year one, percentages who agreed that they had been well prepared ranged from 82% (95% CI: 79-87) at the medical school with the highest level of agreement to 30% (25-35) at the lowest. At year three the range was 70% to 27%. Ethnicity and sex were partial predictors of doctors' level of agreement; following adjustment for them, substantial differences between schools remained. In years one and three, 30% and 34% of doctors specified that feeling unprepared had been a serious or medium-sized problem for them (only 3% in each year regarded it as serious).</p> <p>Conclusions</p> <p>The vast knowledge base of clinical practice makes full preparation impossible. Our statement about feeling prepared is simple yet discriminating and identified some substantial differences between medical schools. Medical schools need feedback from graduates about elements of training that could be improved.</p

    Oxygen Activation and Energy Conservation by Cytochrome c Oxidase

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    This review focuses on the type A cytochrome c oxidases (C cO), which are found in all mitochondria and also in several aerobic bacteria. C cO catalyzes the respiratory reduction of dioxygen (O2) to water by an intriguing mechanism, the details of which are fairly well understood today as a result of research for over four decades. Perhaps even more intriguingly, the membrane-bound C cO couples the O2 reduction chemistry to translocation of protons across the membrane, thus contributing to generation of the electrochemical proton gradient that is used to drive the synthesis of ATP as catalyzed by the rotary ATP synthase in the same membrane. After reviewing the structure of the core subunits of C cO, the active site, and the transfer paths of electrons, protons, oxygen, and water, we describe the states of the catalytic cycle and point out the few remaining uncertainties. Finally, we discuss the mechanism of proton translocation and the controversies in that area that still prevail.Peer reviewe

    Structure of a bacterial cell surface decaheme electron conduit

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    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or participating in extracellular intercytochrome electron exchange along “nanowire” appendages. We present a 3.2-Å crystal structure of one of these decaheme cytochromes, MtrF, that allows the spatial organization of the 10 hemes to be visualized for the first time. The hemes are organized across four domains in a unique crossed conformation, in which a staggered 65-Å octaheme chain transects the length of the protein and is bisected by a planar 45-Å tetraheme chain that connects two extended Greek key split ß-barrel domains. The structure provides molecular insight into how reduction of insoluble substrate (e.g., minerals), soluble substrates (e.g., flavins), and cytochrome redox partners might be possible in tandem at different termini of a trifurcated electron transport chain on the cell surface

    Ultrafast Light-Driven Electron Transfer in a Ru(II)tris(bipyridine)-Labelled Multiheme Cytochrome

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    Multiheme cytochromes attract much attention for their electron transport properties. These proteins conduct electrons across bacterial cell walls, along extracellular filaments, and when purified can serve as bionanoelectronic junctions. Thus, it is important and necessary to identify and understand the factors governing electron transfer in this family of proteins. To this end we have used ultra-fast transient absorbance spectroscopy, to define heme-heme electron transfer dynamics in the representative multiheme cytochrome STC from Shewanella oneidensis in aqueous solution. STC was photo-sensitized by site-selective labelling with a Ru(II)(bipyridine)3 dye and the dynamics of light-driven electron transfer described by a kinetic model corroborated by molecular dynamics simulation and density functional theory calculations. With the dye attached adjacent to STC Heme IV, a rate constant of 87 x 106 s-1 was resolved for Heme IV → Heme III electron transfer. With the dye attached adjacent to STC Heme I, at the opposite terminus of the tetraheme chain, a rate constant of 125 x 106 s-1 was defined for Heme I → Heme II electron transfer. These rates are an order of magnitude faster than previously computed values for unlabeled STC. The Heme III/IV and I/II pairs exemplify the T-shaped heme packing arrangement, prevalent in multiheme cytochromes, whereby the adjacent porphyrin rings lie at 90o with edge-edge (Fe-Fe) distances of ≈6 (11) Å. The results are significant in demonstrating the opportunities for pump-probe spectroscopies to resolve inter-heme electron transfer in Ru-labeled multiheme cytochromes

    Detecting natural disasters, damage, and incidents in the wild

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    Responding to natural disasters, such as earthquakes, floods, and wildfires, is a laborious task performed by on-the-ground emergency responders and analysts. Social media has emerged as a low-latency data source to quickly understand disaster situations. While most studies on social media are limited to text, images offer more information for understanding disaster and incident scenes. However, no large-scale image datasets for incident detection exists. In this work, we present the Incidents Dataset, which contains 446,684 images annotated by humans that cover 43 incidents across a variety of scenes. We employ a baseline classification model that mitigates false-positive errors and we perform image filtering experiments on millions of social media images from Flickr and Twitter. Through these experiments, we show how the Incidents Dataset can be used to detect images with incidents in the wild. Code, data, and models are available online at http://incidentsdataset.csail.mit.edu.Comment: ECCV 202

    Biochemical properties of Paracoccus denitrificans FnrP:Reactions with molecular oxygen and nitric oxide

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    In Paracoccus denitrificans, three CRP/FNR family regulatory proteins, NarR, NnrR and FnrP, control the switch between aerobic and anaerobic (denitrification) respiration. FnrP is a [4Fe-4S] cluster containing homologue of the archetypal O2 sensor FNR from E. coli and accordingly regulates genes encoding aerobic and anaerobic respiratory enzymes in response to O2, and also NO, availability. Here we show that FnrP undergoes O2-driven [4Fe-4S] to [2Fe-2S] cluster conversion that involves up to 2 O2 per cluster, with significant oxidation of released cluster sulfide to sulfane observed at higher O2 concentrations. The rate of the cluster reaction was found to be ~6-fold lower than that of E. coli FNR, suggesting that FnrP can remain transcriptionally active under microaerobic conditions. This is consistent with a role for FnrP in activating expression of the high O2 affinity cytochrome c oxidase under microaerobic conditions. Cluster conversion resulted in dissociation of the transcriptionally active FnrP dimer into monomers. Therefore, along with E. coli FNR, FnrP belongs to the subset of FNR proteins in which cluster type is correlated with association state. Interestingly, two key charged residues, Arg140 and Asp154, that have been shown to play key roles in the monomer-dimer equilibrium in E. coli FNR are not conserved in FnrP, indicating that different protomer interactions are important for this equilibrium. Finally, the FnrP [4Fe-4S] cluster is shown to undergo reaction with multiple NO molecules, resulting in iron nitrosyl species and dissociation into monomers

    Molecular dysfunction associated with the human mitochondrial 3302A>G mutation in the MTTL1 (mt-tRNA(Leu(UUR))) gene

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    The gene encoding mt-tRNA(Leu(UUR)), MT-TL1, is a hotspot for pathogenic mtDNA mutations. Amongst the first to be described was the 3302A>G transition which resulted in a substantial accumulation in patient muscle of RNA19, an unprocessed RNA intermediate including mt-16S rRNA, mt-tRNA(Leu(UUR)) and MTND1. We have now been able to further assess the molecular aetiology associated with 3302A>G in transmitochondrial cybrids. Increased steady-state levels of RNA19 was confirmed, although not to the levels previously reported in muscle. This data was consistent with an increase in RNA19 stability. The mutation resulted in decreased mt-tRNA(Leu(UUR)) levels, but its stability was unchanged, consistent with a defect in RNA19 processing responsible for low tRNA levels. A partial defect in aminoacylation was also identified, potentially caused by an alteration in tRNA structure. These deficiencies lead to a severe defect in respiration in the transmitochondrial cybrids, consistent with the profound mitochondrial disorder originally associated with this mutation
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