144 research outputs found

    Quality Legume-Based Forage Systems for Contrasting Environments: COST Action 852

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    Agricultural systems that reduce environmental degradation, sustain agricultural productivity and economic viability, maintain stable rural communities, enhance the quality of life and respond to increasing demand for livestock products are promoted in developed countries. Though major challenges exist, forage legumes, adapted to a wide range of soil types, climatic conditions and management systems, will become increasingly important components of sustainable agricultural production systems in Europe. Temporal and spatial variation in legume performance often occurs. Compared to pure grass systems, legume-based systems may lead to increased N losses. To what extent ruminants can use the protein from forage legumes, and whether there are differences among species and cultivars are unknown. To improve reliability and the range of forage legumes, we must understand the constraints of environment, the reasons for divergence between species potential and actual performance and the most efficient way to use the herbage. The COST Action 852 - Quality legume-based forage systems for contrasting environments was set up to help resolve some of these questions

    Perspective on Coarse-Graining, Cognitive Load, and Materials Simulation

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    The predictive capabilities of computational materials science today derive from overlapping advances in simulation tools, modeling techniques, and best practices. We outline this ecosystem of molecular simulations by explaining how important contributions in each of these areas have fed into each other. The combined output of these tools, techniques, and practices is the ability for researchers to advance understanding by efficiently combining simple models with powerful software. As specific examples, we show how the prediction of organic photovoltaic morphologies have improved by orders of magnitude over the last decade, and how the processing of reacting epoxy thermosets can now be investigated with million-particle models. We discuss these two materials systems and the training of materials simulators through the lens of cognitive load theory. For students, the broad view of ecosystem components should facilitate understanding how the key parts relate to each other first, followed by targeted exploration. In this way, the paper is organized in loose analogy to a coarse-grained model: The main components provide basic framing and accelerated sampling from which deeper research is better contextualized. For mentors, this paper is organized to provide a snapshot in time of the current simulation ecosystem and an on-ramp for simulation experts into the literature on pedagogical practice

    Lytic activity by temperate phages of Pseudomonas aeruginosa in long-term cystic fibrosis chronic lung infections

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    Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of cystic fibrosis (CF) patients. The transmissible Liverpool epidemic strain (LES) harbours multiple inducible prophages (LESϕ2; LESϕ3; LESϕ4; LESϕ5; and LESϕ6), some of which are known to confer a competitive advantage in an in vivo rat model of chronic lung infection. We used quantitative PCR (Q-PCR) to measure the density and dynamics of all five LES phages in the sputa of 10 LES-infected CF patients over a period of 2 years. In all patients, the densities of free-LES phages were positively correlated with the densities of P. aeruginosa, and total free-phage densities consistently exceeded bacterial host densities 10–100-fold. Further, we observed a negative correlation between the phage-to-bacterium ratio and bacterial density, suggesting a role for lysis by temperate phages in regulation of the bacterial population densities. In 9/10 patients, LESϕ2 and LESϕ4 were the most abundant free phages, which reflects the differential in vitro induction properties of the phages. These data indicate that temperate phages of P. aeruginosa retain lytic activity after prolonged periods of chronic infection in the CF lung, and suggest that temperate phage lysis may contribute to regulation of P. aeruginosa density in vivo

    Ecological and evolutionary mechanisms driving within-patient emergence of antimicrobial resistance

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    The ecological and evolutionary mechanisms of antimicrobial resistance (AMR) emergence within patients and how these vary across bacterial infections are poorly understood. Increasingly widespread use of pathogen genome sequencing in the clinic enables a deeper understanding of these processes. In this Review, we explore the clinical evidence to support four major mechanisms of within-patient AMR emergence in bacteria: spontaneous resistance mutations; in situ horizontal gene transfer of resistance genes; selection of pre-existing resistance; and immigration of resistant lineages. Within-patient AMR emergence occurs across a wide range of host niches and bacterial species, but the importance of each mechanism varies between bacterial species and infection sites within the body. We identify potential drivers of such differences and discuss how ecological and evolutionary analysis could be embedded within clinical trials of antimicrobials, which are powerful but underused tools for understanding why these mechanisms vary between pathogens, infections and individuals. Ultimately, improving understanding of how host niche, bacterial species and antibiotic mode of action combine to govern the ecological and evolutionary mechanism of AMR emergence in patients will enable more predictive and personalized diagnosis and antimicrobial therapies

    Temperate phages enhance pathogen fitness in chronic lung infection

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    The Liverpool Epidemic Strain (LES) is a polylysogenic, transmissible strain of Pseudomonas aeruginosa, capable of superinfecting existing P. aeruginosa respiratory infections in individuals with cystic fibrosis (CF). The LES phages are highly active in the CF lung and may have a role in the competitiveness of the LES in vivo. In this study, we tested this by competing isogenic PAO1 strains that differed only by the presence or absence of LES prophages in a rat model of chronic lung infection. Lysogens invaded phage-susceptible populations, both in head-to-head competition and when invading from rare, in the spatially structured, heterogeneous lung environment. Appreciable densities of free phages in lung tissue confirmed active phage lysis in vivo. Moreover, we observed lysogenic conversion of the phage-susceptible competitor. These results suggest that temperate phages may have an important role in the competitiveness of the LES in chronic lung infection by acting as anti-competitor weapons

    Temperate phages both mediate and drive adaptive evolution in pathogen biofilms

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    Temperate phages drive genomic diversification in bacterial pathogens. Phage-derived sequences are more common in pathogenic than non-pathogenic taxa, and are associated with changes in pathogen virulence. High abundance and mobilisation of temperate phages within hosts suggests that temperate phages could promote within-host evolution of bacterial pathogens. However,their role in pathogen evolution has not been experimentally tested. We experimentally evolved replicate populations of Pseudomonas aeruginosa with or without a community of three temperate phages active in cystic fibrosis (CF) lung infections, including the transposable phage, ɸ4, which is closely related to phage D3112. Populations grew as free-floating biofilms in artificial sputum medium, mimicking sputum of CF lungs where P. aeruginosa is an important pathogen and undergoes evolutionary adaptation and diversification during chronic infection. While bacterial populations adapted to the biofilm environment in both treatments, population genomic analysis revealed that phages altered both the trajectory and mode of evolution. Populations evolving with phages exhibited a greater degree of parallel evolution and faster selective sweeps than populations without phages. Phage ɸ4, integrated randomly into the bacterial chromosome but integrations into motility-associated genes and regulators of quorum sensing systems essential for virulence were selected in parallel, strongly suggesting that these insertional inactivation mutations were adaptive. Temperate phages, and in particular transposable phages, are therefore likely to facilitate adaptive evolution of bacterial pathogens within hosts

    Equipping Health Professions Educators to Better Address Medical Misinformation

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    As part of a cooperative agreement with the US Centers for Disease Control and Prevention (Federal Award Identification Number [FAIN]: NU50CK000586), the Association of American Medical Colleges (AAMC) began a strategic initiative in 2022 both to increase confidence in COVID-19 vaccines and to address medical misinformation and mistrust through education in health professions contexts. Specifically, the AAMC solicited proposals for integrating competency-based, interprofessional strategies to mitigate health misinformation into new or existing curricula. Five Health Professions Education Curricular Innovations subgrantees received support from the AAMC in 2022 and reflected on the implementation of their ideas in a series of meetings over several months. Subgrantees included the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Florida International University Herbert Wertheim College of Medicine, the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, the Maine Medical Center/Tufts University School of Medicine, and the University of Chicago Pritzker School of Medicine. This paper comprises insights from each of the teams and overarching observations regarding the challenges and opportunities involved with leveraging health professions education to address medical misinformation and improve patient health

    Route of drug administration in out-of-hospital cardiac arrest: A protocol for a randomised controlled trial (PARAMEDIC-3)

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    © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).AIMS: The PARAMEDIC-3 trial evaluates the clinical and cost-effectiveness of an intraosseous first strategy, compared with an intravenous first strategy, for drug administration in adults who have sustained an out-of-hospital cardiac arrest. METHODS: PARAMEDIC-3 is a pragmatic, allocation concealed, open-label, multi-centre, superiority randomised controlled trial. It will recruit 15,000 patients across English and Welsh ambulance services. Adults who have sustained an out-of-hospital cardiac arrest are individually randomised to an intraosseous access first strategy or intravenous access first strategy in a 1:1 ratio through an opaque, sealed envelope system. The randomised allocation determines the route used for the first two attempts at vascular access. Participants are initially enrolled under a deferred consent model.The primary clinical-effectiveness outcome is survival at 30-days. Secondary outcomes include return of spontaneous circulation, neurological functional outcome, and health-related quality of life. Participants are followed-up to six-months following cardiac arrest. The primary health economic outcome is incremental cost per quality-adjusted life year gained. CONCLUSION: The PARAMEDIC-3 trial will provide key information on the clinical and cost-effectiveness of drug route in out-of-hospital cardiac arrest.Trial registration: ISRCTN14223494, registered 16/08/2021, prospectively registered.Peer reviewe
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