138 research outputs found

    A Singular Perturbation Analysis for \\Unstable Systems with Convective Nonlinearity

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    We use a singular perturbation method to study the interface dynamics of a non-conserved order parameter (NCOP) system, of the reaction-diffusion type, for the case where an external bias field or convection is present. We find that this method, developed by Kawasaki, Yalabik and Gunton for the time-dependant Ginzburg-Landau equation and used successfully on other NCOP systems, breaks down for our system when the strength of bias/convection gets large enough.Comment: 5 pages, PostScript forma

    The impact of economic crises on communicable disease transmission and control: a systematic review of the evidence.

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    There is concern among public health professionals that the current economic downturn, initiated by the financial crisis that started in 2007, could precipitate the transmission of infectious diseases while also limiting capacity for control. Although studies have reviewed the potential effects of economic downturns on overall health, to our knowledge such an analysis has yet to be done focusing on infectious diseases. We performed a systematic literature review of studies examining changes in infectious disease burden subsequent to periods of crisis. The review identified 230 studies of which 37 met our inclusion criteria. Of these, 30 found evidence of worse infectious disease outcomes during recession, often resulting from higher rates of infectious contact under poorer living circumstances, worsened access to therapy, or poorer retention in treatment. The remaining studies found either reductions in infectious disease or no significant effect. Using the paradigm of the "SIR" (susceptible-infected-recovered) model of infectious disease transmission, we examined the implications of these findings for infectious disease transmission and control. Key susceptible groups include infants and the elderly. We identified certain high-risk groups, including migrants, homeless persons, and prison populations, as particularly vulnerable conduits of epidemics during situations of economic duress. We also observed that the long-term impacts of crises on infectious disease are not inevitable: considerable evidence suggests that the magnitude of effect depends critically on budgetary responses by governments. Like other emergencies and natural disasters, preparedness for financial crises should include consideration of consequences for communicable disease control

    Abnormal ECG Findings in Athletes: Clinical Evaluation and Considerations.

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    PURPOSE OF REVIEW: Pre-participation cardiovascular evaluation with electrocardiography is normal practice for most sporting bodies. Awareness about sudden cardiac death in athletes and recognizing how screening can help identify vulnerable athletes have empowered different sporting disciplines to invest in the wellbeing of their athletes. RECENT FINDINGS: Discerning physiological electrical alterations due to athletic training from those representing cardiac pathology may be challenging. The mode of investigation of affected athletes is dependent on the electrical anomaly and the disease(s) in question. This review will highlight specific pathological ECG patterns that warrant assessment and surveillance, together with an in-depth review of the recommended algorithm for evaluation

    International criteria for electrocardiographic interpretation in athletes: Consensus statement.

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    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD

    Cardiac Sarcoidosis: When and How to Treat Inflammation

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    Sarcoidosis is a complex, multisystem inflammatory disease with a heterogeneous clinical spectrum. Approximately 25% of patients with systemic sarcoidosis will have cardiac involvement that portends a poorer outcome. The diagnosis, particularly of isolated cardiac sarcoidosis, can be challenging. A paucity of randomised data exist on who, when and how to treat myocardial inflammation in cardiac sarcoidosis. Despite this, corticosteroids continue to be the mainstay of therapy for the inflammatory phase, with an evolving role for steroid-sparing and biological agents. This review explores the immunopathogenesis of inflammation in sarcoidosis, current evidence-based treatment indications and commonly used immunosuppression agents. It explores a multidisciplinary treatment and monitoring approach to myocardial inflammation and outlines current gaps in our understanding of this condition, emerging research and future directions in this field

    Biophysical mechanisms of single-cell interactions with microtopographical cues

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    Biophysical cues encoded in the extracellular matrix (ECM) are increasingly being explored to control cell behavior in tissue engineering applications. Recently, we showed that cell adhesion to microtopographical structures (“micropegs”) can suppress proliferation in a manner that may be blunted by inhibiting cellular contractility, suggesting that this effect is related to altered cell-scaffold mechanotransduction. We now directly investigate this possibility at the microscale through a combination of live-cell imaging, single-cell mechanics methods, and analysis of gene expression. Using time-lapse imaging, we show that when cells break adhesive contacts with micropegs, they form F-actin-filled tethers that extend and then rupture at a maximum, critical length that is greater than trailing-edge tethers observed on topographically flat substrates. This critical tether length depends on myosin activation, with inhibition of Rho-associated kinase abolishing topography-dependent differences in tether length. Using cellular de-adhesion and atomic force microscopy indentation measurements, we show that the micropegs enhance cell-scaffold adhesive interactions without changing whole-cell elasticity. Moreover, micropeg adhesion increases expression of specific mechanotransductive genes, including RhoA GTPase and myosin heavy chain II, and, in myoblasts, the functional marker connexin 43. Together, our data support a model in which microtopographical cues alter the local mechanical microenvironment of cells by modulating adhesion and adhesion-dependent mechanotransductive signaling

    Paediatric acute hepatitis of unknown aetiology : a national investigation and adenoviraemia case-control study in the UK

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    Funding Information: This work was undertaken as part of a national enhanced incident by UK public health agencies. We thank the parents and guardians of the children who gave up their valuable time to speak to the public health investigation teams; without their support we could not have been able to undertake a thorough investigation. We are grateful to the many paediatricians and liver specialists who reported cases to us and responded to follow-up with further information. We also thank Ezra Linley and Simon Tonge of the UK Health Security Agency Seroepidemiology Unit for rapidly providing serum samples for testing. We would like to thank the Incident Management Teams of the UK nations, members of the incident cells, epidemiology, laboratory, and local Health Protection Teams who supported the investigations, in particular: Katy Sinka, Mike Gent, Suzanna Howes, Eileen Gallagher, Selene Corsini, Eleanor Clarke, Rajani Raghu, Kelsey Mowat, Iain Hayden, Matt Hibbert, Skye Firminger, Catriona Angel, Donna Haskins, Kay Ratcliffe, Hannah Emmett, Alex Elliot, Helen Hughes, Sarah Deeny, Sarah Garner, Sarah Gerver, Flora Stevens, Paula Blomquist, Gabriel Gurmail Kauffman, Kristine Cooper, Hannah Taylor, Giovanni Leonardi, Michelle Dickinson and Michelle Watson from England; Kimberly Marsh, Michael Lockhart, David Yirrell, Sandra Currie, Kate Templeton, Samantha Shepherd, Roisin Ure, Jim McMenamin, Rachel Tayler, Louisa Pollock, Antonia Ho, Chris Cunningham and Hayley Peacock from Scotland; and Katie Binley and Meg Wallace from Northern Ireland.Peer reviewe

    Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

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    Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio
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