1,969 research outputs found

    Detection of trends in the 7-day sustained low-flow time series of Irish rivers

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    A combination of statistical hypothesis testing methods (Mann-Whitney, Mann-Kendall and Spearman’s rho) and visual exploratory analysis were used to investigate trends in Irish 7-day sustained low-flow (7SLF) series possibly driven by changes in summer rainfall patterns. River flow data from 33 gauging stations covering most major Irish rivers were analysed, after excluding catchments where low flows are influenced by significant human interventions. A statistically significant increasing trend in the 7SLF series was identified by all three tests at eight gauging stations; in contrast, a statistically significant decreasing trend was identified by all three tests at four stations. The stations with increasing trends are mainly located within the western half of the country, while there is no particular spatial clustering of the stations showing a decreasing trend. Further analysis suggests that the increasing trend in the 7SLF time series persists regardless of the starting year of analysis. However, the decreasing trend occurs only when years prior to 1970 are included in the analysis, and disappears, or is reversed, if only the data from 1970 and onwards are considered. There is strong evidence that the direction of the trends in the 7SLF series is determined mainly by trends in total summer rainfall amounts, i.e. is linked to weather

    Derivation of a Fuzzy National Phosphorus Export Model using 84 Irish Catchments

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    Implementation of appropriate management strategies to mitigate diffuse phosphorus (P) pollution at the catchment scale is vitally important for the sustainable development of water resources in Ireland. An important element in the process of implementing such strategies is the prediction of their impacts on P concentrations in a catchment using a reliable mathematical model. In this study, a state-of-the-art adaptive neuro-fuzzy inference system (ANFIS) has been used to develop a new national P model capable of estimating average annual ortho-P concentrations at un-gauged catchments. Data from 84 catchments dominated by diffuse P pollution were used in developing and testing the model. Six different split-sample scenarios were used to partition the total number of the catchments into two sets, one to calibrate and the other to validate the model. The k-means clustering algorithm was used to partition the sets into clusters of catchments with similar features. Then for each scenario and for each cluster case, 11 different models, each of which consists of a linear regression sub-model for each cluster, were formulated by using different input variables selected from among six spatially distributed variables including phosphorus desorption index (PDI), runoff risk index (RRI), geology (GEO), groundwater (GW), land use (LU), and soil (SO). The success of the new approach over the conventional lumped, empirical, modelling approach was evident from the improved results obtained for most of the cases. In addition the results highlighted the importance of using information on PDI and RRI as explanatory input variables to simulate the average annual ortho-P concentrations

    Microstructure-specific Hardening of Ferritic-Martensitic Steels pre and post 15 dpa Neutron Irradiation at 330°C: A Dislocation Dynamics Study

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    In this work, we used Dislocation Dynamics (DD) simulations to investigate the role of the hierarchical defects microstructure of ferritic-martensitic steel Eurofer97 in determining its hardening behavior. A Representative Volume Element (RVE) for DD simulation is identified based on the typical martensitic lath size. Material properties for DD simulations in b.c.c Eurofer97 are determined, including the dislocation mobility parameters. The dependence of material parameters on temperature is fitted to experimental yield strength measurements carried out at room temperature and 330 °C, respectively. Voids and precipitates observed in the microstructure, such as M23C6 and Tantalum-rich MX, are considered in our DD simulations as inclusions with realistic size distribution and volume density, while 〈1 1 1〉 -and 〈1 0 0〉 -type irradiation loops are included directly in the DD simulations. The lath structure, together with its typical precipitates arrangement and the different crystallographic orientation of the martensitic blocks can also be captured in the simulations. DD simulations are used to extract microstructure-specific hardening parameters, which can be used to simulate the properties of Eurofer97 at the engineering scale

    Co-Delivery of mRNA and pDNA Using Thermally Stabilized Coacervate-Based Core-Shell Nanosystems

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    Co-delivery of different species of protein-encoding polynucleotides, e.g., messenger RNA (mRNA) and plasmid DNA (pDNA), using the same nanocarrier is an interesting topic that remains scarcely researched in the field of nucleic acid delivery. The current study hence aims to explore the possibility of the simultaneous delivery of mRNA (mCherry) and pDNA (pAmCyan) using a single nanocarrier. The latter is based on gelatin type A, a biocompatible, and biodegradable biopolymer of broad pharmaceutical application. A core-shell nanostructure is designed with a thermally stabilized gelatin–pDNA coacervate in its center. Thermal stabilization enhances the core’s colloidal stability and pDNA shielding effect against nucleases as confirmed by nanoparticle tracking analysis and gel electrophoresis, respectively. The stabilized, pDNA-loaded core is coated with the cationic peptide protamine sulfate to enable additional surface-loading with mRNA. The dual-loaded core-shell system transfects murine dendritic cell line DC2.4 with both fluorescent reporter mRNA and pDNA simultaneously, showing a transfection efficiency of 61.4 ± 21.6% for mRNA and 37.6 ± 19.45% for pDNA, 48 h post-treatment, whereas established commercial, experimental, and clinical transfection reagents fail. Hence, the unique co-transfectional capacity and the negligible cytotoxicity of the reported system may hold prospects for vaccination among other downstream applications

    Assessment of Industrial Load for Demand Response across Western Interconnect

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    Demand response (DR) has the ability to both increase power grid reliability and potentially reduce operating system costs. Understanding the role of demand response in grid modeling has been difficult due to complex nature of the load characteristics compared to the modeled generation and the variation in load types. This is particularly true of industrial loads, where hundreds of different industries exist with varying availability for demand response. We present a framework considering industrial loads for the development of availability profiles that can provide more regional understanding and can be inserted into analysis software for further study. The developed framework utilizes a number of different informational resources, algorithms, and real-world measurements to perform a bottom-up approach in the development of a new database with representation of the potential demand response resource in the industrial sector across the U.S. This tool houses statistical values of energy and demand response (DR) potential by industrial plant and geospatially locates the information for aggregation for different territories without proprietary information. This report will discuss this framework and the analyzed quantities of demand response for Western Interconnect (WI) in support of evaluation of the cost production modeling with power grid modeling efforts of demand response

    Bioresorbable Composite Polymeric Materials for Tissue Engineering Applications

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    This review covers the development of bioresorbable polymeric composites for applications in tissue engineering. Various commercially available bioresobable polymers are described, with emphasis on recent bioresorbable composites based on natural and synthetic polymers. Bioresorbable polymers contain hydrolyzable bonds, which are subjected to chemical degradation via either reactive hydrolysis or enzyme-catalyzed active hydrolysis. For synthetic polymers, chemical hydrolysis is the most important mode of degradation. The degradation rate can be controlled by varying the molecular weight and crystallinity. Examples of bioresorbable polymers are: polyurethane, poly(D,L)lactide, poly(lactic-co-glycolic) acid, poly(α-hydroxy acids), cross-linked polyester hydrogels, poly(orthoesters), polyanhydrides and polyethylene glycol

    Pandemic (H1N1) 2009 and Hajj Pilgrims Who Received Predeparture Vaccination, Egypt

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    In Egypt, vaccination against pandemic (H1N1) 2009 virus was required of pilgrims departing for the 2009 Hajj. A survey of 551 pilgrims as they returned to Egypt found 542 (98.1% [weighted]) reported receiving the vaccine; 6 (1.0% [weighted]) were infected with influenza virus A (H3N2) but none with pandemic (H1N1) 2009 virus

    Correlation between mechanical dissipation and improved X-band electromagnetic shielding capabilities of amine functionalized graphene/thermoplastic polyurethane composites

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    The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.eurpolymj.2017.08.038 © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Graphene-based polymer nanocomposites have demonstrated significant promise to create commercially viable electromagnetic interference (EMI) shielding to protect the next-generation of electronic materials from radiative pollution. In the present study, we carry out a systematic analysis of the dynamic mechanical, dielectric, electrical and X-band shielding properties of thermoplastic polyurethane (TPU) elastomer filled with amine functionalized graphene obtained by the rapid thermal expansion of graphite oxide. By preparation of nanocomposites based on modified and unmodified graphene using solution mixing and hot compression moulding, we demonstrate that the modification with 2-aminoethyl methacrylate enhances the EMI shielding from 14 to 25 dB. We also show by fracture analysis, cross-sectional transmission electron microscopy and dynamic mechanical analysis that the modification significantly strengthens the interfacial interactions between TPU and the functionalized graphene at the same filler loading. We find that the dominant shielding mechanism is through absorption and discuss the correlation between the viscoelastic mechanical loss tangent and the more effective dissipation of absorbed EM radiation which might account for the discrepancy between the theoretically predicted and experimentally observed EMI SE.NSERC Discover

    18Fluorodeoxyglucose Accumulation in Arterial Tissues Determined by PET Signal Analysis

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    BACKGROUND: Arterial 18fluorodeoxyglucose (FDG) positron emission tomography (PET) is considered a measure of atherosclerotic plaque macrophages and is used for quantification of disease activity in clinical trials, but the distribution profile of FDG across macrophages and other arterial cells has not been fully clarified. OBJECTIVES: The purpose of this study was to analyze FDG uptake in different arterial tissues and their contribution to PET signal in normal and atherosclerotic arteries. METHODS: Wild-type and D374Y-PCSK9 transgenic Yucatan minipigs were fed a high-fat, high-cholesterol diet to induce atherosclerosis and subjected to a clinical FDG-PET and computed tomography scan protocol. Volumes of arterial media, intima/lesion, macrophage-rich, and hypoxic tissues were measured in serial histological sections. Distributions of FDG in macrophages and other arterial tissues were quantified using modeling of the in vivo PET signal. In separate transgenic minipigs, the intra-arterial localization of FDG was determined directly by autoradiography. RESULTS: Arterial FDG-PET signal appearance and intensity were similar to human imaging. The modeling approach showed high accuracy in describing the FDG-PET signal and revealed comparable FDG accumulation in macrophages and other arterial tissues, including medial smooth muscle cells. These findings were verified directly by autoradiography of normal and atherosclerotic arteries. CONCLUSIONS: FDG is taken up comparably in macrophage-rich and -poor arterial tissues in minipigs. This offers a mechanistic explanation to a growing number of observations in clinical imaging studies that have been difficult to reconcile with macrophage-selective FDG uptake.This study was supported by the Danish Council for Independent Research/Medical Sciences, Lundbeck Foundation, Danish Heart Foundation, and Aarhus University Research Foundation (AU IDEAS). The CNIC is supported by the Ministerio de Ciencia, Innovación y Universidades, and the Pro CNIC Foundation; and is a Severo Ochoa Center of Excellence (SEV-2015-0505). Dr. Bentzon has served as a consultant for Novo Nordisk A/S; and has within the last 5 years received an investigator-initiated preclinical research grant from Regeneron PharmaceuticalsS
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