415 research outputs found

    Staged inertial microfluidic focusing for complex fluid enrichment

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    Microfluidic inertial focusing reliably and passively aligns small particles and cells through a combination of competing inertial fluid forces. The equilibrium behavior of inertially focused particles in straight channels has been extensively characterized and has been shown to be a strong function of channel size, geometry and particle size. We demonstrate that channels of varying geometry may be combined to produce a staged device capable of high throughput particle and cell concentration and efficient single pass complex fluid enrichment. Straight and asymmetrically curved microchannels were combined in series to accelerate focusing dynamics and improve concentration efficiency. We have investigated single and multiple pass concentration efficiency and results indicate that these devices are appropriate for routine cell handling operations, including buffer exchange. We demonstrate the utility of these devices by performing a ubiquitous fluorescence staining assay on-chip while sacrificing very little sample or processing time relative to centrifugation. Staged concentration is particularly desirable for point of care settings in which more conventional instrumentation is impractical or cost-prohibitive.United States. Department of Defense (Congressionally Directed Medical Research Program, Prostate Cancer Research Program Award number W81XWH-13-1-0272)University of Wyoming. IDeA Networks of Biomedical Research Excellence (program P20RR016474)University of Wyoming. IDeA Networks of Biomedical Research Excellence (program P20GM103432)United States. Department of Defense (Congressionally Directed Medical Research Program, Prostate Cancer Research Program Award number W81XWH-13-1-0273)United States. National Aeronautics and Space Administration (Wyoming NASA Space Grant Consortium (NASA Grant #NNX10A095H))National Science Foundation (U.S.) (Wyoming Experimental Program to Stimulate Competitive Research (Grant EPS-0447681)

    High quality care following orthopaedic injury in Zambia:A qualitative, patient-centred study

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    Background: Injuries are a significant cause of mortality and morbidity, particular in low- and middle-income countries (LMICs). While there is a focus on increasing injury care capacity, less attention is given to assessing, improving, and understanding the quality of care provided, especially from a patient perspective. This study therefore aims to understand what patients from a Zambian orthopaedic ward believe good quality care to be, to identify its key components, and contribute to better understanding what patients believe local healthcare priorities could be.Methods: Patients admitted to the orthopaedic ward of a Zambian tertiary care hospital were invited to take part in-depth face-to-face interviews. Interviews were continued until thematic saturation was achieved. Interviews were recorded and transcribed. Analysis was done using an inductive grounded theory approach.Results: Of 13 patients approached, 12 consented to take part. Analysis of the themes from the transcripts led to the emergence of four core categories of quality care which are important to the patient: i) restoring the patient to normality (category: ‘restoring normality’), ii) establishing trust between patients and providers (‘trusting the provider’), iii) respecting the patient and allowing them to maintain autonomy (‘autonomy and respect’) iv) finding ways for patients to enjoy their time in the hospital (‘enjoying life’). From these results, a patient perspective theory of quality care emerged. This theory posits the idea that high-quality care in this context needs to fulfil these four core categories. Additionally, these core categories were ranked on significance and priority.Conclusion: The hierarchy of core categories could help to identify areas to improve care quality in this setting. Not only has this study helped to determine local priorities for achieving high-quality care but can encourage others to test injured patient perceptions of care quality in comparable settings

    Optimality of broken extremals

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    In this paper we analyse the optimality of broken Pontryagin extremal for an n-dimensional affine control system with a control parameter, taking values in a k- dimensional closed ball. We prove the optimality of broken normal extremals when n = 3 and the controllable vector fields form a contact distribution, and when the Lie algebra of the controllable fields is locally orthogonal to the singular locus and the drift does not belong to it. Moreover, if k = 2, we show the optimality of any broken extremal even abnormal when the controllable fields do not form a contact distribution in the point of singularity.Comment: arXiv admin note: text overlap with arXiv:1610.0675

    Interleukin 15 Is Required for Proliferative Renewal of Virus-specific Memory CD8 T Cells

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    The generation and efficient maintenance of antigen-specific memory T cells is essential for long-lasting immunological protection. In this study, we examined the role of interleukin (IL)-15 in the generation and maintenance of virus-specific memory CD8 T cells using mice deficient in either IL-15 or the IL-15 receptor α chain. Both cytokine- and receptor-deficient mice made potent primary CD8 T cell responses to infection with lymphocytic choriomeningitis virus (LCMV), effectively cleared the virus and generated a pool of antigen-specific memory CD8 T cells that were phenotypically and functionally similar to memory CD8 T cells present in IL-15+/+ mice. However, longitudinal analysis revealed a slow attrition of virus-specific memory CD8 T cells in the absence of IL-15 signals.This loss of CD8 T cells was due to a severe defect in the proliferative renewal of antigen-specific memory CD8 T cells in IL-15−/− mice. Taken together, these results show that IL-15 is not essential for the generation of memory CD8 T cells, but is required for homeostatic proliferation to maintain populations of memory cells over long periods of time

    Smets-Wouters '03 model revisited - an implementation in gEcon

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    This paper presents an implementation of the well-known Smets-Wouters 2003 model for Euro Area using the gEcon package - what we call the ``third generation'' DSGE modelling toolbox. Our exercise serves three goals. First, we show how gEcon can be used to implement an important - from both applications and historical perspective - model. Second, through rigorous exposition enforced by the gEcon’s block-agent paradigm we analyse all the Smets-Wouters model’s building blocks. Last, but not least, the implementation presented here serves as a natural starting point for important from applications point of view extensions, like opening the economy, introducing non-lump-sum taxes, or adding sectors to the model economy. Full model implementation is attached

    Clinical trial protocol of the ASTER trial: a double-blind, randomized, placebo-controlled phase III trial evaluating the use of acetylsalicylic acid (ASA) for enhanced early detection of colorectal neoplasms

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    Immunochemical fecal occult blood tests (iFOBTs) are increasingly used for colorectal cancer (CRC) screening. In our preceding observational study, sensitivity for detecting advanced colorectal neoplasms by iFOBT was 70.8% among users of low-dose acetylsalicylic acid compared with 35.9% among non-users (p = 0.001), whereas there were only very small differences in specificity. In receiver operating characteristics (ROC) analyses, the area under the curve (AUC) was much higher for acetylsalicylic acid users than for non-users, with particularly strong differences in men (0.87 versus 0.68, p = 0.003). These findings suggested that use of acetylsalicylic acid before conduct of iFOBT might be a promising approach to improve non-invasive screening for CRC. Methods/design: In this randomized, double-blind, placebo-controlled trial, the diagnostic performance of two iFOBTs for detecting advanced colorectal neoplasms after a single low-dose of acetylsalicylic acid (300 mg) compared to placebo is evaluated. Acetylsalicylic acid or placebo is administered at least 5 days before a planned, study-independent colonoscopic screening in 2400 participants aged 40 to 80 years. Stool samples are obtained before and on three different days after the single dose of acetylsalicylic acid or placebo. In addition, optional blood samples are taken for future biomarker analyses. The diagnostic performance of the iFOBTs will be compared to the results of the colonoscopy as a gold standard for the diagnosis of colorectal neoplasms. Additionally, gender-specific performance of the tests and gain in diagnostic performance by test application on multiple days will be evaluated. Discussion: If the findings from our preceding observational study will be confirmed in this large trial, the proposed low-risk, inexpensive intervention would considerably improve the diagnostic accuracy of iFOBTs and thus lead to enhanced early detection of colorectal neoplasms. Thus, the results of this trial may have a large public health impact. Trial registration This trial was registered before recruitment of the participants in www.clinicaltrialsregister.eu on the 30th of May 2012: EudraCT No.: 2011–005603-32 and in www.drks.de on 13th of March 2012: German Clinical Trials Register DRKS-ID: DRKS00003252

    The full health, economic, and social benefits of prospective Strep A vaccination.

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    Recent research has documented a wide range of health, economic, and social benefits conferred by vaccination, beyond the direct reductions in morbidity, mortality, and future healthcare costs traditionally captured in economic evaluations. In this paper, we describe the societal benefits that would likely stem from widespread administration of safe and effective vaccines against Streptococcus pyogenes (Strep A), which was estimated to be the fifth-leading cause of infectious disease deaths globally prior to the COVID-19 pandemic. We then estimate the global societal gains from prospective Strep A vaccination through a value-per-statistical-life approach. Estimated aggregate lifetime benefits for 30 global birth cohorts range from 1.7to1.7 to 5.1 trillion, depending on the age at which vaccination is administered and other factors. These results suggest that the benefits of Strep A vaccination would be large and justify substantial investment in the vaccines' development, manufacture, and delivery

    Modeling the potential health impact of prospective Strep A vaccines

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    The World Health Organization published the preferred product characteristics for a Group A Streptococcus (Strep A) vaccine in 2018. Based on these parameters for the age of vaccination, vaccine efficacy, duration of protection from vaccine-derived immunity, and vaccination coverage, we developed a static cohort model to estimate the projected health impact of Strep A vaccination at the global, regional, and national levels and by country-income category. We used the model to analyse six strategic scenarios. Based on Strep A vaccine introduction between 2022 and 2034 for the primary scenario, we estimated vaccination at birth for 30 vaccinated cohorts could avert 2.5 billion episodes of pharyngitis, 354 million episodes of impetigo, 1.4 million episodes of invasive disease, 24 million episodes of cellulitis, and 6 million cases of rheumatic heart disease globally. Vaccination impact in terms of burden averted per fully vaccinated individual is highest in North America for cellulitis and in Sub-Saharan Africa for rheumatic heart disease

    Pathogenic Activation and Therapeutic Blockage of FcαR-Expressing Polymorphonuclear Leukocytes in IgA Pemphigus

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    Pathomechanisms in IgA pemphigus are assumed to rely on Fc-dependent cellular activation by antigen-specific IgA autoantibodies; however, models for the disease and more detailed pathophysiologic data are lacking. In this study, we aimed to establish in vitro models of disease for IgA pemphigus, allowing us to study the effects of the interaction of anti-keratinocyte IgA with cell surface FcαRs. Employing multiple in vitro assays, such as a skin cryosection assay and a human skin organ culture model, in this study, we present mechanistic data for the pathogenesis of IgA pemphigus, mediated by anti–desmoglein 3 IgA autoantibodies. Our results reveal that this disease is dependent on FcαR-mediated activation of leukocytes in the epidermis. Importantly, this cell-dependent pathology can be dose-dependently abrogated by peptide-mediated inhibition of FcαR:IgA-Fc interaction, as confirmed in an additional model for IgA-dependent disease, that is, IgA vasculitis. These data suggest that IgA pemphigus can be modeled in vitro and that IgA pemphigus and IgA vasculitis are FcαR-dependent disease entities that can be specifically targeted in these experimental systems
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