44 research outputs found

    Magnetic field amplification and electron acceleration to near-energy equipartition with ions by a mildly relativistic quasi-parallel plasma protoshock

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    The prompt emissions of gamma-ray bursts are seeded by radiating ultrarelativistic electrons. Internal shocks propagating through a jet launched by a stellar implosion, are expected to amplify the magnetic field & accelerate electrons. We explore the effects of density asymmetry & a quasi-parallel magnetic field on the collision of plasma clouds. A 2D relativistic PIC simulation models the collision of two plasma clouds, in the presence of a quasi-parallel magnetic field. The cloud density ratio is 10. The densities of ions & electrons & the temperature of 131 keV are equal in each cloud. The mass ratio is 250. The peak Lorentz factor of the electrons is determined, along with the orientation & strength of the magnetic field at the cloud collision boundary. The magnetic field component orthogonal to the initial plasma flow direction is amplified to values that exceed those expected from shock compression by over an order of magnitude. The forming shock is quasi-perpendicular due to this amplification, caused by a current sheet which develops in response to the differing deflection of the incoming upstream electrons & ions. The electron deflection implies a charge separation of the upstream electrons & ions; the resulting electric field drags the electrons through the magnetic field, whereupon they acquire a relativistic mass comparable to the ions. We demonstrate how a magnetic field structure resembling the cross section of a flux tube grows in the current sheet of the shock transition layer. Plasma filamentation develops, as well as signatures of orthogonal magnetic field striping. Localized magnetic bubbles form. Energy equipartition between the ion, electron & magnetic energy is obtained at the shock transition layer. The electronic radiation can provide a seed photon population that can be energized by secondary processes (e.g. inverse Compton).Comment: 12 pages, 15 Figures, accepted to A&

    Community of Practice of Promotoras de Salud to address health inequities during and beyond the COVID-19 pandemic

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    Using principles of Community-Based Participatory Research, we describe a community of practice for community health workers and promotoras (CHW/Ps) to address COVID-19 inequities in the Latinx community. We offer a concrete example of how programs can engage CHW/Ps as full partners in the research process, and how programs can support CHW/Ps’ capacity and workforce development during implementation. We conducted four focus groups with CHW/Ps (n = 31) to understand needs and invited 15 participants to the community of practice to work on issues identified by the group. We examined impact according to number of community members reached, types of outreach activities, surveys, and online views of educational materials. Process evaluation involved two focus groups with seven organizations and a Ripple Effects Mapping session with the CHW/Ps. Our community of practice has built CHW/Ps’ capacity via 31 workshop and co-created culturally and linguistically relevant COVID-19 materials that have reached over 40,000 community members and over 3 million people online. The community of practice proved effective in supporting CHW/Ps to address COVID-19 inequities in the Latinx community. Our evaluations demonstrated benefits for community-academic partnerships, for CHW/Ps, and for the community. This model represents an innovative workforce training model to address health inequities and can be applied to other health topics

    Productivity links morphology, symbiont specificity, and bleaching in the evolution of Caribbean octocoral symbioses

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    Many cnidarians host endosymbiotic dinoflagellates from the genus Symbiodinium. It is generally assumed that the symbiosis is mutualistic, where the host benefits from symbiont photosynthesis while providing protection and photosynthetic substrates. Diverse assemblages of symbiotic gorgonian octocorals can be found in hard bottom communities throughout the Caribbean. While current research has focused on the phylo- and population genetics of gorgonian symbiont types and their photo-physiology, relatively less work has focused on biogeochemical benefits conferred to the host and how these benefits vary across host species. Here, we examine this symbiosis among 11 gorgonian species collected in Bocas del Toro, Panama. By coupling light and dark bottle incubations (P/R) with 13C-bicarbonate tracers, we quantified the link between holobiont oxygen metabolism with carbon assimilation and translocation from symbiont to host. Our data show that P/R varied among species, and was correlated with colony morphology and polyp size. Sea fans and sea plumes were net autotrophs (P/R > 1.5) while nine species of sea rods were net heterotrophs with most below compensation (P/R < 1.0). 13C assimilation corroborated the P/R results, and maximum δ13Chost values were strongly correlated with polyp size, indicating higher productivity by colonies with high polyp SA:V. A survey of gorgonian-Symbiodinium associations revealed that productive species maintain specialized, obligate symbioses and are more resistant to coral bleaching, whereas generalist and facultative associations are common among sea rods that have higher bleaching sensitivities. Overall, productivity and polyp size had strong phylogenetic signals with carbon fixation and polyp size showing evidence of trait covariance.published_or_final_versio

    Identification of unique neoantigen qualities in long-term survivors of pancreatic cancer

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    Pancreatic ductal adenocarcinoma is a lethal cancer with fewer than 7% of patients surviving past 5 years. T-cell immunity has been linked to the exceptional outcome of the few long-term survivors1,2, yet the relevant antigens remain unknown. Here we use genetic, immunohistochemical and transcriptional immunoprofiling, computational biophysics, and functional assays to identify T-cell antigens in long-term survivors of pancreatic cancer. Using whole-exome sequencing and in silico neoantigen prediction, we found that tumours with both the highest neoantigen number and the most abundant CD8+ T-cell infiltrates, but neither alone, stratified patients with the longest survival. Investigating the specific neoantigen qualities promoting T-cell activation in long-term survivors, we discovered that these individuals were enriched in neoantigen qualities defined by a fitness model, and neoantigens in the tumour antigen MUC16 (also known as CA125). A neoantigen quality fitness model conferring greater immunogenicity to neoantigens with differential presentation and homology to infectious disease-derived peptides identified long-term survivors in two independent datasets, whereas a neoantigen quantity model ascribing greater immunogenicity to increasing neoantigen number alone did not. We detected intratumoural and lasting circulating T-cell reactivity to both high-quality and MUC16 neoantigens in long-term survivors of pancreatic cancer, including clones with specificity to both high-quality neoantigens and predicted cross-reactive microbial epitopes, consistent with neoantigen molecular mimicry. Notably, we observed selective loss of high-quality and MUC16 neoantigenic clones on metastatic progression, suggesting neoantigen immunoediting. Our results identify neoantigens with unique qualities as T-cell targets in pancreatic ductal adenocarcinoma. More broadly, we identify neoantigen quality as a biomarker for immunogenic tumours that may guide the application of immunotherapies

    Symbiotic Futures: Health, Well-being and Care in the Post-Covid World

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    The "Symbiotic Futures: Health, Well-being and Care in the Post-Covid World" project was jointly conceived by the Innovation School at Glasgow School of Art and the Institute of Cancer Sciences at the University of Glasgow. The project partnership involved a community of experts working across both organisations including the University of Glasgow’s new Mazumdar-Shaw Advanced Research Centre (ARC). Future experiences is a collaborative, futures-focused design project where students benefit from the input of a community of experts to design speculative future worlds and experiences based on research within key societal contexts. This iteration of the project asked the students to consider what happens in the Post-Covid landscape ten years from now, where symbiotic experiences of health, well-being and care have evolved to the extent that new forms of medical practice, health communities and cultures of care transform how we interact with each other, with professionals and the world around us. The GSA Innovation School’s final year BDes Product Design students and faculty formed a dynamic community of practice with health, wellbeing and care practitioners and researchers from The University of Glasgow and beyond. This gave the students the opportunity to reflect on the underlying complexities of the future of health, well-being and care, technological acceleration, human agency and quality of life, to envision a 2031 blueprint as a series of six future world exhibits, and design the products, services and system experiences for the people and environments within it. In the first part of the project (Stage 1), Future worlds are groups of students working together on specific topics, to establish the context for their project and collaborate on research and development. In this iteration of Future Experiences, the "Health, Well-being and Care" worlds were clustered together around ‘People focused’ and ‘Environment focused’, but also joined up across these groups to create pairs of worlds, and in the process generate symbiosis between the groups. These worlds were then the starting points which the students explored in their individual projects. The second part of the project (Stage 2) saw individual students select an aspect of their Future World research to develop as a design direction, which they then prototyped and produced as products, services, and/or systems. These are designed for specific communities, contexts or scenarios of use defined by the students to communicate a future experience. These Future experiences reflect the societal contexts explored during the research phase, projected 10 years into the future, and communicated in a manner that makes the themes engaging and accessible. The deposited materials are arranged as follows: 1. Project Landscape Map - A report and blueprint for the project that gives a visual overview of the structure and timeline of the project. 2. Stage one data folders - the data folders for stage one of the project are named after the themes the groups explored to create their Future Worlds. 3. Stage two data folders - the data folders for stage two of the project are named after the individual students who created the project

    Outcome of the First wwPDB/CCDC/D3R Ligand Validation Workshop.

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    Crystallographic studies of ligands bound to biological macromolecules (proteins and nucleic acids) represent an important source of information concerning drug-target interactions, providing atomic level insights into the physical chemistry of complex formation between macromolecules and ligands. Of the more than 115,000 entries extant in the Protein Data Bank (PDB) archive, ∟75% include at least one non-polymeric ligand. Ligand geometrical and stereochemical quality, the suitability of ligand models for in silico drug discovery and design, and the goodness-of-fit of ligand models to electron-density maps vary widely across the archive. We describe the proceedings and conclusions from the first Worldwide PDB/Cambridge Crystallographic Data Center/Drug Design Data Resource (wwPDB/CCDC/D3R) Ligand Validation Workshop held at the Research Collaboratory for Structural Bioinformatics at Rutgers University on July 30-31, 2015. Experts in protein crystallography from academe and industry came together with non-profit and for-profit software providers for crystallography and with experts in computational chemistry and data archiving to discuss and make recommendations on best practices, as framed by a series of questions central to structural studies of macromolecule-ligand complexes. What data concerning bound ligands should be archived in the PDB? How should the ligands be best represented? How should structural models of macromolecule-ligand complexes be validated? What supplementary information should accompany publications of structural studies of biological macromolecules? Consensus recommendations on best practices developed in response to each of these questions are provided, together with some details regarding implementation. Important issues addressed but not resolved at the workshop are also enumerated.The workshop was supported by funding to RCSB PDB by the National Science Foundation (DBI 1338415); PDBe by the Wellcome Trust (104948); PDBj by JST-NBDC; BMRB by the National Institute of General Medical Sciences (GM109046); D3R by the National Institute of General Medical Sciences (GM111528); registration fees from industrial participants; and tax-deductible donations to the wwPDB Foundation by the Genentech Foundation and the Bristol-Myers Squibb Foundation.This is the final version of the article. It first appeared from Cell Press via https://doi.org//10.1016/j.str.2016.02.01
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