749 research outputs found

    Antibiotic Resistance Gene Abundances Correlate with Metal and Geochemical Conditions in Archived Scottish Soils

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    The vast majority of antibiotic resistant genes (ARG) acquired by human pathogens have originated from the natural environment. Therefore, understanding factors that influence intrinsic levels of ARG in the environment could be epidemiologically significant. The selection for metal resistance often promotes AR in exposed organisms; however, the relationship between metal levels in nature and the intrinsic presence of ARG has not been fully assessed. Here, we quantified, using qPCR, the abundance of eleven ARG and compared their levels with geochemical conditions in randomly selected soils from a Scottish archive. Many ARG positively correlated with soil copper levels, with approximately half being highly significant (p<0.05); whereas chromium, nickel, lead, and iron also significantly correlated with specific ARG. Results show that geochemical metal conditions innately influence the potential for AR in soil. We suggest soil geochemical data might be used to estimate baseline gene presence on local, regional and global scales within epidemiological risk studies related to AR transmission from the environment

    Draft genome sequence of Neurospora crassa strain FGSC 73

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    Citation: Baker, S. E., Schackwitz, W., Lipzen, A., Martin, J., Haridas, S., LaButti, K., . . . McCluskey, K. (2016). Draft genome sequence of Neurospora crassa strain FGSC 73. Genome Announcements, 3(2). doi:10.1128/genomeA.00074-15Citation: Baker, S., Schackwitz, W., Lipzen, A., . . . McCluskey, K. (2015). Draft Genome Sequence of Neurospora crassa Strain FGSC 73. Genome Announcements, 3(2), e00074-15. https://doi.org/10.1128/genomeA.00074-15We report the elucidation of the complete genome of the Neurospora crassa (Shear and Dodge) strain FGSC 73, a mat-a, trp-3 mutant strain. The genome sequence around the idiotypic mating type locus represents the only publicly available sequence for a mat-a strain. 40.42 Megabases are assembled into 358 scaffolds carrying 11,978 gene models. © 2015 Baker et al

    A prototype personal aerosol sampler based on electrostatic precipitation and electrowetting-on-dielectric actuation of droplets

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    This is an Open Access article, distributed under the terms of the Open Government Licence. http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved. The version of record (T. G. Foat, et al, 'A prototype personal aerosol sampler based on electrostatic precipitation and electrowetting-on-dielectric actuation of droplets', Journal of Aerosol Science, Vol. 95, pp. 43-53, May 2016) is available online at doi: https://doi.org/10.1016/j.jaerosci.2016.01.007.An electrostatic precipitator (ESP) based personal sampler with a laboratory based electrowetting-on-dielectric (EWOD) concentrator could provide a high concentration rate personal aerosol sampler system. A prototype system has been developed based on the concept of a lightweight personal ESP collecting aerosol particles onto a hydrophobic surface followed by the use of an EWOD actuated droplet system to transfer the deposited sample into a microlitre size water droplet.A personal sampler system could provide military or civilian personnel with a wide area biological monitoring capability supplying information on who has been infected, what they have been infected with, how much material they were exposed to and possibly where and when they were infected. Current commercial-off-the-shelf (COTS) personal sampler solutions can be bulky and use volumes of water to extract the sample that are typically a thousand times greater than the proposed method.Testing of the prototype ESP at a sample flow rate of 5Lmin-1 demonstrated collection efficiencies greater than 80% for sodium fluorescein particles larger than 4μm diameter and of approximately 50% at 1.5μm. The ESP-EWOD system collection efficiency measured for Bacillus atrophaeus (BG) spores with an air sample flow rate of 20L min-1 was 2.7% with a concentration rate of 1.9×105 min-1. This was lower than expected due to the corona ions from the ESP affecting the hydrophobicity of the collection surface and hence the EWOD efficiency. However, even with this low efficiency the concentration rate is more than an order of magnitude higher than the theoretical maximum of the best current COTS personal sampler. For an optimised system, ESP-EWOD system efficiency should be higher than 32% with a comparable increase in concentration rate.Peer reviewe

    Ferromagnetism in Ga1-xMnxP: evidence for inter-Mn exchange mediated by localized holes within a detached impurity band

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    We demonstrate that in ferromagnetic Ga1-xMnxP exchange is mediated by holes localized in a Mn-derived band. For x<0.06, infrared absorption and photoconductivity spectra indicate the presence of a Mn impurity band which is not merged with the valence band. At temperatures above TC (<65 K) electrical transport is dominated by excitation across this energy gap while nearest neighbor hopping dominates below TC. Magnetization measurements reveal a moment of 3.5 Bohr magnetons per substitutional Mn, while the large anomalous Hall signal unambiguously demonstrates that the ferromagnetism is carrier-mediated.Comment: Equation 1 correcte

    Assessing competency in Evidence Based Practice: strengths and limitations of current tools in practice

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    <p>Abstract</p> <p>Background</p> <p>Evidence Based Practice (EBP) involves making clinical decisions informed by the most relevant and valid evidence available. Competence can broadly be defined as a concept that incorporates a variety of domains including knowledge, skills and attitudes. Adopting an evidence-based approach to practice requires differing competencies across various domains including literature searching, critical appraisal and communication. This paper examines the current tools available to assess EBP competence and compares their applicability to existing assessment techniques used in medicine, nursing and health sciences.</p> <p>Discussion</p> <p>Only two validated assessment tools have been developed to specifically assess all aspects of EBP competence. Of the two tools (<it>Berlin </it>and <it>Fresno </it>tools), only the <it>Fresno </it>tool comprehensively assesses EBP competency across all relevant domains. However, both tools focus on assessing EBP competency in medical students; therefore neither can be used for assessing EBP competency across different health disciplines. The Objective Structured Clinical Exam (OSCE) has been demonstrated as a reliable and versatile tool to assess clinical competencies, practical and communication skills. The OSCE has scope as an alternate method for assessing EBP competency, since it combines assessment of cognitive skills including knowledge, reasoning and communication. However, further research is needed to develop the OSCE as a viable method for assessing EBP competency.</p> <p>Summary</p> <p>Demonstrating EBP competence is a complex task – therefore no single assessment method can adequately provide all of the necessary data to assess complete EBP competence. There is a need for further research to explore how EBP competence is best assessed; be it in written formats, such as the <it>Fresno </it>tool, or another format, such as the OSCE. Future tools must also incorporate measures of assessing how EBP competence affects clinician behaviour and attitudes as well as clinical outcomes in real-time situations. This research should also be conducted across a variety of health disciplines to best inform practice.</p

    Development and psychometric testing of an instrument to evaluate cognitive skills of evidence based practice in student health professionals

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    <p>Abstract</p> <p>Background</p> <p>Health educators need rigorously developed instruments to evaluate cognitive skills relating to evidence based practice (EBP). Previous EBP evaluation instruments have focused on the acquisition and appraisal of the evidence and are largely based in the medical profession. The aim of this study was to develop and validate an EBP evaluation instrument to assess EBP cognitive skills for entry-level health professional disciplines.</p> <p>Methods</p> <p>The Fresno test of competence in evidence based medicine was considered in the development of the 'Knowledge of Research Evidence Competencies' instrument (K-REC). The K-REC was reviewed for content validity. Two cohorts of entry-level students were recruited for the pilot study, those who had been exposed to EBP training (physiotherapy students, n = 24), and who had not been exposed to EBP training (human movement students, n = 76). The K-REC was administered to one cohort of students (n = 24) on two testing occasions to evaluate test-retest reliability. Two raters independently scored the first test occasion (n = 24) to evaluate the inter-rater reliability of the marking guidelines. Construct validity was assessed by comparison of the two groups, 'exposed' and 'non-exposed', and the percentage of students achieving a 'pass' score in each of these groups. Item difficulty was established.</p> <p>Results</p> <p>Among the 100 participants (24 EBP 'exposed', and 76 EBP 'non-exposed' students), there was a statistically significant (<it>p </it>< 0.0001) difference in the total K-REC scores. The test-retest and inter-rater reliability of the individual items and total scores ranged from moderate to excellent (measured by Cohen's Kappa and ICC, range: 0.62 to perfect agreement).</p> <p>Conclusions</p> <p>The K-REC instrument is a valid and reliable evaluation instrument of cognitive skills of EBP in entry-level student health professionals. The instrument is quick to disseminate and easy to score, making it a suitable instrument for health educators to employ to evaluate students' knowledge of EBP or in the evaluation of entry-level EBP training.</p

    Natural HLA Class I Polymorphism Controls the Pathway of Antigen Presentation and Susceptibility to Viral Evasion

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    HLA class I polymorphism creates diversity in epitope specificity and T cell repertoire. We show that HLA polymorphism also controls the choice of Ag presentation pathway. A single amino acid polymorphism that distinguishes HLA-B*4402 (Asp116) from B*4405 (Tyr116) permits B*4405 to constitutively acquire peptides without any detectable incorporation into the transporter associated with Ag presentation (TAP)-associated peptide loading complex even under conditions of extreme peptide starvation. This mode of peptide capture is less susceptible to viral interference than the conventional loading pathway used by HLA-B*4402 that involves assembly of class I molecules within the peptide loading complex. Thus, B*4402 and B*4405 are at opposite extremes of a natural spectrum in HLA class I dependence on the PLC for Ag presentation. These findings unveil a new layer of MHC polymorphism that affects the generic pathway of Ag loading, revealing an unsuspected evolutionary trade-off in selection for optimal HLA class I loading versus effective pathogen evasion

    Killer whales and marine mammal trends in the North Pacific : a re-examination of evidence for sequential megafauna collapse and the prey-switching hypothesis

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    This paper is not subject to U.S. copyright. The definitive version was published in Marine Mammal Science 23 (2007): 766–802, doi:10.1111/j.1748-7692.2006.00093.x.Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling's removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem
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