688 research outputs found

    Sediment Transport Impacts Upon Culvert Hydraulics

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    Sedimentation buildup and accumulation can cause serious impediments to the hydraulic capacity of culvert systems. There has not been any significant research to date regarding the behavior of bed load transport nor the implications of bed forms upon the hydraulics associated with culvert flow. The primary objective of this study was to investigate how sediment transport occurs in a culvert and to then develop a methodology and test setup to successfully investigate this sediment transport. The investigation was limited to studying culvert and pipeline transport of alluvial material in sand and gravel sizes. This dissertation develops a semi-empirical bed load transport equation from existing open channel flow models to be used in predicting sediment yields in culvert applications. Incipient motion and critical shear stresses were investigated for application into eight empirically based models. The methods analyzed include the Meyer-Peter Müller, Engelund and Hansen, Shields, Toffaleti (as seen in the United States Army Corps of Engineers program HEC RAS), Schoklitsch, DuBoy, Yang, and Rottner methods. These methods were tested for predictive accuracy to physically modeled bed load transport data obtained from a 304.8 mm (11.89 in) diameter culvert. Tests involved fully pressurized, partially pressurized inlet controlled, and open channel flow regimes for a variety of bed elevations and bedforms. Bedform regime and associated resistance impacts on flow energy were presented to better understand their hydraulic consequence in culvert applications. An extensive literature review regarding sediment transport in both open channel and closed conduit applications is provided to develop a foundation of knowledge to pursue further research in this area. This literature review summarizes the current body of scientific knowledge that is applicable to sediment transport in culverts. Investigations into both historical and current works are cited throughout this studies literature review. A tested methodology is presented for the investigation of sediment bed load transport in culvert applications. Development of a procedure for the testing of critical shear limits and bed load transport is outlined. A detailed application example is provided. Recommended changes in testing techniques and physical model are made for the next generation of culvert sediment transport research

    Evaluating and Redesigning the Self-Monitoring Tool

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    In order to facilitate self-monitoring interventions designed by the Faculty of Computer Science Universitas Indonesia, a web-based self-monitoring tool was created. This paper aims to evaluate the tool regarding its usability and user-experiences prior to its wide adoption. The User-Experience Questionnaire (UEQ) and the System Usability Scale (SUS) were used to evaluate the self-monitoring tool. The tool was implemented in a Human-Computer Interaction course during odd semesters and the evaluations were taken by the participants of the course. The evaluation results were analyzed to help determine whether the tool needs to be enhanced or improved. Based the results, a new design of self-monitoring tool was developed using the interface design principles

    Evaluating and Redesigning the Self-Monitoring Tool

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    In order to facilitate self-monitoring interventions designed by the Faculty of Computer Science Universitas Indonesia a web-based self-monitoring tool was created. This paper aims to evaluate the tool regarding its usability and user-experiences prior to its wide adoption. The System Usability Scale (SUS) and the User-Experience Questionnaire (UEQ) were used to evaluate the self-monitoring tool. The tool was implemented in a Human-Computer Interaction course during odd semesters, and the evaluations were taken by the participants of the course. The evaluation results were analysed to help determine whether the tool needs to be enhanced or improved. Based on the results, a new design of self-monitoring tool was developed using the interface design principles

    Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'.

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    Innate immune cells must be able to distinguish between direct binding to microbes and detection of components shed from the surface of microbes located at a distance. Dectin-1 (also known as CLEC7A) is a pattern-recognition receptor expressed by myeloid phagocytes (macrophages, dendritic cells and neutrophils) that detects β-glucans in fungal cell walls and triggers direct cellular antimicrobial activity, including phagocytosis and production of reactive oxygen species (ROS). In contrast to inflammatory responses stimulated upon detection of soluble ligands by other pattern-recognition receptors, such as Toll-like receptors (TLRs), these responses are only useful when a cell comes into direct contact with a microbe and must not be spuriously activated by soluble stimuli. In this study we show that, despite its ability to bind both soluble and particulate β-glucan polymers, Dectin-1 signalling is only activated by particulate β-glucans, which cluster the receptor in synapse-like structures from which regulatory tyrosine phosphatases CD45 and CD148 (also known as PTPRC and PTPRJ, respectively) are excluded (Supplementary Fig. 1). The 'phagocytic synapse' now provides a model mechanism by which innate immune receptors can distinguish direct microbial contact from detection of microbes at a distance, thereby initiating direct cellular antimicrobial responses only when they are required

    Serum samples can be substituted by plasma samples for the diagnosis of paratuberculosis

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    Employing plasma samples rather than serum samples for serological paratuberculosis diagnosis is practical, especially when bovine TB is assessed in the same cattle herd with the gamma interferon bovine avian (IFN- BA) test. We demonstrate that antibody titers in serum and plasma samples, utilizing the PARACHECK® ELISA kit, are highly comparable (Cohen’s kappa test, k = 0.955). We conclude that serum can be replaced with plasma in this commercially available antibody detection assay resulting in working hour savings for sampling and blood sample work-up and cost reductions for materials and sample storage.Employing plasma samples rather than serum samples for serological paratuberculosis diagnosis is practical, especially when bovine TB is assessed in the same cattle herd with the gamma interferon bovine avian (IFN- BA) test. We demonstrate that antibody titers in serum and plasma samples, utilizing the PARACHECK® ELISA kit, are highly comparable (Cohen’s kappa test, k = 0.955). We conclude that serum can be replaced with plasma in this commercially available antibody detection assay resulting in working hour savings for sampling and blood sample work-up and cost reductions for materials and sample storage

    Twin-S: A Digital Twin for Skull-base Surgery

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    Purpose: Digital twins are virtual interactive models of the real world, exhibiting identical behavior and properties. In surgical applications, computational analysis from digital twins can be used, for example, to enhance situational awareness. Methods: We present a digital twin framework for skull-base surgeries, named Twin-S, which can be integrated within various image-guided interventions seamlessly. Twin-S combines high-precision optical tracking and real-time simulation. We rely on rigorous calibration routines to ensure that the digital twin representation precisely mimics all real-world processes. Twin-S models and tracks the critical components of skull-base surgery, including the surgical tool, patient anatomy, and surgical camera. Significantly, Twin-S updates and reflects real-world drilling of the anatomical model in frame rate. Results: We extensively evaluate the accuracy of Twin-S, which achieves an average 1.39 mm error during the drilling process. We further illustrate how segmentation masks derived from the continuously updated digital twin can augment the surgical microscope view in a mixed reality setting, where bone requiring ablation is highlighted to provide surgeons additional situational awareness. Conclusion: We present Twin-S, a digital twin environment for skull-base surgery. Twin-S tracks and updates the virtual model in real-time given measurements from modern tracking technologies. Future research on complementing optical tracking with higher-precision vision-based approaches may further increase the accuracy of Twin-S

    Amplitude measurements of Faraday waves

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    A light reflection technique is used to measure quantitatively the surface elevation of Faraday waves. The performed measurements cover a wide parameter range of driving frequencies and sample viscosities. In the capillary wave regime the bifurcation diagrams exhibit a frequency independent scaling proportional to the wavelength. We also provide numerical simulations of the full Navier-Stokes equations, which are in quantitative agreement up to supercritical drive amplitudes of 20%. The validity of an existing perturbation analysis is found to be limited to 2.5% overcriticaly.Comment: 7 figure

    Microbial ligand costimulation drives neutrophilic steroid-refractory asthma

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    Funding: The authors thank the Wellcome Trust (102705) and the Universities of Aberdeen and Cape Town for funding. This research was also supported, in part, by National Institutes of Health GM53522 and GM083016 to DLW. KF and BNL are funded by the Fonds Wetenschappelijk Onderzoek, BNL is the recipient of an European Research Commission consolidator grant and participates in the European Union FP7 programs EUBIOPRED and MedALL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Innate Recognition of Fungal Cell Walls

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    The emergence of fungal infections as major causes of morbidity and mortality in immunosuppressed individuals has prompted studies into how the host recognizes fungal pathogens. Fungi are eukaryotes and as such share many similarities with mammalian cells. The most striking difference, though, is the presence of a cell wall that serves to protect the fungus from environmental stresses, particularly osmotic changes [1]. This task is made challenging because the fungus must remodel itself to allow for cell growth and division, including the conversion to different morphotypes, such as occurs during germination of spherical spores into filamentous hyphae. The cell wall also connects the fungus with its environment by triggering intracellular signaling pathways and mediating adhesion to other cells and extracellular matrices. Here, important facts and concepts critical for understanding innate sensing of the fungal cell wall by mammalian pathogens are reviewed

    Health-related quality of life in diabetic patients and controls without diabetes in refugee camps in the Gaza strip: a cross-sectional study

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    BACKGROUND: Prevalence of diabetes mellitus is increasing in developed and developing countries. Diabetes is known to strongly affect the health-related quality of life (HRQOL). HRQOL is also influenced by living conditions. We analysed the effects of having diabetes on HRQOL under the living conditions in refugee camps in the Gaza strip. METHODS: We studied a sample of 197 diabetic patients who were recruited from three refugee camps in the Gaza strip and 197 age- and sex-matched controls living in the same camps. To assess HRQOL, we used the World Health Organization Quality of Life questionnaire (WHOQOL-BREF) including four domains (physical health, psychological, social relations and environment). Domain scores were compared for cases (diabetic patients) and controls (persons without diabetes) and the impact of socio-economic factors was evaluated in both groups. RESULTS: All domains were strongly reduced in diabetic patients as compared to controls, with stronger effects in physical health (36.7 vs. 75.9 points of the 0–100 score) and psychological domains (34.8 vs. 70.0) and weaker effects in social relationships (52.4 vs. 71.4) and environment domains (23.4 vs. 36.2). The impact of diabetes on HRQOL was especially severe among females and older subjects (above 50 years). Low socioeconomic status had a strong negative impact on HRQOL in the younger age group (<50 years). CONCLUSION: HRQOL is strongly reduced in diabetic patients living in refugee camps in the Gaza strip. Women and older patients are especially affected
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