2,286 research outputs found

    Virus Sharing, Genetic Sequencing, and Global Health Security

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    The WHO’s Pandemic Influenza Preparedness (PIP) Framework was a milestone global agreement designed to promote the international sharing of biological samples to develop vaccines, while that ensuring poorer countries would have access to those vaccines. Since the PIP Framework was negotiated, scientists have developed the capacity to use genetic sequencing data (GSD) to develop synthetic viruses rapidly for product development of life-saving technologies in a time-sensitive global emergency—threatening to unravel the Framework. Access to GSD may also have major implications for biosecurity, biosafety, and intellectual property (IP). By rendering the physical transfer of viruses antiquated, GSD may also undermine the effectiveness of the PIP Framework itself, with disproportionate impacts on poorer countries. We examine the changes that need to be made to the PIP Framework to address the growing likelihood that GSD might be shared instead of physical virus samples. We also propose that the international community harness this opportunity to expand the scope of the PIP Framework beyond only influenza viruses with pandemic potential. In light of non-influenza pandemic threats such as the Middle East Respiratory Syndrome (MERS) and Ebola, we call for an international agreement on the sharing of the benefits of research – such as vaccines and treatments – for other infectious diseases to ensure not only a more secure and healthy world, but also a more just world, for humanity

    Calculation of coercivity of magnetic nanostructures at finite temperatures

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    We report a finite temperature micromagnetic method (FTM) that allows for the calculation of the coercive field of arbitrary shaped magnetic nanostructures at time scales of nanoseconds to years. Instead of directly solving the Landau-Lifshitz-Gilbert equation, the coercive field is obtained without any free parameter by solving a non linear equation, which arises from the transition state theory. The method is applicable to magnetic structures where coercivity is determined by one thermally activated reversal or nucleation process. The method shows excellent agreement with experimentally obtained coercive fields of magnetic nanostructures and provides a deeper understanding of the mechanism of coercivity.Comment: submitted to Phys. Rev.

    The Global Health System: Strengthening National Health Systems as the Next Step for Global Progress

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    In the second in a series of articles on the changing nature of global health institutions, Julio Frenk offers a framework to better understand national health systems and their role in global health

    Niche inheritance: a cooperative pathway to enhance cancer cell fitness though ecosystem engineering

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    Cancer cells can be described as an invasive species that is able to establish itself in a new environment. The concept of niche construction can be utilized to describe the process by which cancer cells terraform their environment, thereby engineering an ecosystem that promotes the genetic fitness of the species. Ecological dispersion theory can then be utilized to describe and model the steps and barriers involved in a successful diaspora as the cancer cells leave the original host organ and migrate to new host organs to successfully establish a new metastatic community. These ecological concepts can be further utilized to define new diagnostic and therapeutic areas for lethal cancers.Comment: 8 pages, 1 Table, 4 Figure

    "The difference that makes a difference": highlighting the role of variable contexts within an HIV Prevention Community Randomised Trial (HPTN 071/PopART) in 21 study communities in Zambia and South Africa.

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    This paper explores contextual heterogeneity within a community randomised trial HPTN 071 (Population Effects of Antiretroviral Treatment to Reduce HIV Transmission) carried out in 21 study communities (12 Zambian, 9 South African). The trial evaluates the impact of a combination HIV prevention package (including household-based HIV counselling and testing and anti-retroviral treatment (ART) eligibility regardless of CD4-count) on HIV incidence. The selection, matching and randomisation of study communities relied on key epidemiological and demographic variables and community and stakeholder support. In 2013, following the selection of study communities, a "Broad Brush Survey" (BBS) approach was used to rapidly gather qualitative data on each study community, prior to the implementation of the trial intervention. First-year process indicator intervention data (2014-2015) were collected during the household-based intervention by community lay workers. Using an open/closed typology of urban communities (indicating more or less heterogeneity), this qualitative inquiry presents key features of 12 Zambian communities using a list of four meta-indicators (physical features, social organisation, networks and community narratives). These indicators are then compared with four intervention process indicators in a smaller set of four study communities. The process indicators selected for this analysis indicate response to the intervention (uptake) amongst adults. The BBS qualitative data are used to interpret patterns of similarity and variability in the process indicators across four communities. We found that meta-indicators of local context helped to interpret patterns of similarity and variability emerging across and within the four communities. Features especially significant for influencing heterogeneity in process indicators include proportion of middle-class residents, proximity to neighbouring communities and town centre, the scale of the informal economy, livelihood-linked mobility, presence of HIV stakeholders over time and commitment to community action. Future interdisciplinary analysis is needed to explore if these patterns of difference continue to hold up over the full intervention period and all intervention communities

    Multiscale nature of hysteretic phenomena: Application to CoPt-type magnets

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    We suggest a workable approach for the description of multiscale magnetization reversal phenomena in nanoscale magnets and apply it to CoPt-type alloys. We show that their hysteretic properties are governed by two effects originating at different length scales: a peculiar splitting of domain walls and their strong pinning at antiphase boundaries. We emphasize that such multiscale nature of hysteretic phenomena is a generic feature of nanoscale magnetic materials.Comment: 4 pages (revtex 4), 2 color EPS figure

    HIV cure research in the time of COVID-19 - Antiretroviral therapy treatment interruption trials: A discussion paper

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    This discussion paper addresses the safety of HIV cure studies, particularly those involving stopping antiretroviral therapy, known as an analytic treatment interruption (ATI) in the context of the SARS-CoV-2 pandemic. More than 30 studies listed on ClinicalTrials.gov include an ATI and many others were planned to begin over the next 12 months but most were halted due to the COVID-19 pandemic. We consider the ethics, risks and practical considerations to be taken into account before re-opening HIV cure clinical trials, noting the specific risks of ATI in the context of circulating SARS-CoV-2

    The Suprafroth (Superconducting Froth)

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    The structure and dynamics of froths have been subjects of intense interest due to the desire to understand the behaviour of complex systems where topological intricacy prohibits exact evaluation of the ground state. The dynamics of a traditional froth involves drainage and drying in the cell boundaries, thus it is irreversible. We report a new member to the froths family: suprafroth, in which the cell boundaries are superconducting and the cell interior is normal phase. Despite very different microscopic origin, topological analysis of the structure of the suprafroth shows that statistical von Neumann and Lewis laws apply. Furthermore, for the first time in the analysis of froths there is a global measurable property, the magnetic moment, which can be directly related to the suprafroth structure. We propose that this suprafroth is a new, model system for the analysis of the complex physics of two-dimensional froths
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