384 research outputs found

    Multiobjective optimization of water distribution systems accounting for economic cost, hydraulic reliability, and greenhouse gas emissions

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    In this paper, three objectives are considered for the optimization of water distribution systems (WDSs): the traditional objectives of minimizing economic cost and maximizing hydraulic reliability and the recently proposed objective of minimizing greenhouse gas (GHG) emissions. It is particularly important to include the GHG minimization objective for WDSs involving pumping into storages or water transmission systems (WTSs), as these systems are the main contributors of GHG emissions in the water industry. In order to better understand the nature of tradeoffs among these three objectives, the shape of the solution space and the location of the Pareto-optimal front in the solution space are investigated for WTSs and WDSs that include pumping into storages, and the implications of the interaction between the three objectives are explored from a practical design perspective. Through three case studies, it is found that the solution space is a U-shaped curve rather than a surface, as the tradeoffs among the three objectives are dominated by the hydraulic reliability objective. The Pareto-optimal front of real-world systems is often located at the "elbow" section and lower "arm" of the solution space (i.e., the U-shaped curve), indicating that it is more economic to increase the hydraulic reliability of these systems by increasing pipe capacity (i.e., pipe diameter) compared to increasing pumping power. Solutions having the same GHG emission level but different cost-reliability tradeoffs often exist. Therefore, the final decision needs to be made in conjunction with expert knowledge and the specific budget and reliability requirements of the system. © 2013. American Geophysical Union. All Rights Reserved.Wenyan Wu, Holger R. Maier, and Angus R. Simpso

    The catalytic core of DEMETER guides active DNA demethylation in Arabidopsis.

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    The Arabidopsis DEMETER (DME) DNA glycosylase demethylates the maternal genome in the central cell prior to fertilization and is essential for seed viability. DME preferentially targets small transposons that flank coding genes, influencing their expression and initiating plant gene imprinting. DME also targets intergenic and heterochromatic regions, but how it is recruited to these differing chromatin landscapes is unknown. The C-terminal half of DME consists of 3 conserved regions required for catalysis in vitro. We show that this catalytic core guides active demethylation at endogenous targets, rescuing dme developmental and genomic hypermethylation phenotypes. However, without the N terminus, heterochromatin demethylation is significantly impeded, and abundant CG-methylated genic sequences are ectopically demethylated. Comparative analysis revealed that the conserved DME N-terminal domains are present only in flowering plants, whereas the domain architecture of DME-like proteins in nonvascular plants mainly resembles the catalytic core, suggesting that it might represent the ancestral form of the 5mC DNA glycosylase found in plant lineages. We propose a bipartite model for DME protein action and suggest that the DME N terminus was acquired late during land plant evolution to improve specificity and facilitate demethylation at heterochromatin targets

    Behavioural Informatics for Improving Water Hygiene Practice based on IoT Environment

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    The development of Internet of Things (IoT) and latest Information and Communication Technologies (ICT) have changed the nature of healthcare monitoring and health behaviour intervention in many applications. Water hygiene and water conservation behaviour intervention as important influence factors to human health are gaining much attentions for improving sustained sanitation practice. Based on face-to-face delivery, typical behaviour intervention method is costly and hardly to provide all day access to personalised intervention guidance and feedbacks. In this study, we presented a behavioural information system and water use behaviour model using IoT platform. Using Expanded Theory of Planned Behaviour (ETPB) and adopted structure equation model, this study offers a solution for understanding the behaviour intervention mechanism and methodology for developing empirical model. A case study of behaviour intervention model is presented by utilising residential water conservation behaviour data collected in China. Results suggested that cultural differences have significant influences on the understanding of intervention drivers, promoting projects and increasing awareness, which could improve the behaviour intervention efficiency and further facilitate the improvement of water hygiene practice. The performance evaluation of water saving dimension is discussed as well in the pape

    Neutralization of SARS-CoV-2 spike pseudotyped virus by recombinant ACE2-Ig

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, China, at the end of 2019, and there are currently no specific antiviral treatments or vaccines available. SARS-CoV-2 has been shown to use the same cell entry receptor as SARSCoV, angiotensin-converting enzyme 2 (ACE2). In this report, we generate a recombinant protein by connecting the extracellular domain of human ACE2 to the Fc region of the human immunoglobulin IgG1. A fusion protein containing an ACE2 mutant with low catalytic activity is also used in this study. The fusion proteins are then characterized. Both fusion proteins have a high binding affinity for the receptor-binding domains of SARS-CoV and SARS-CoV-2 and exhibit desirable pharmacological properties in mice. Moreover, the fusion proteins neutralize virus pseudotyped with SARS-CoV or SARS-CoV-2 spike proteins in vitro. As these fusion proteins exhibit cross-reactivity against coronaviruses, they have potential applications in the diagnosis, prophylaxis, and treatment of SARS-CoV-2

    Exosomes: the next frontier in vaccine development and delivery

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    Exosomes are small disk-shaped extracellular vesicles (EVs) that are naturally released into the environment by different types of cells. Exosomes range from 30-150 nm in size and contain complex RNA and proteins. They are widely found in body fluids such as blood, saliva, urine and breast milk and participate in cell communication by functioning as cell messengers. Almost all cell types can transmit information and exchange substances through the production and release of exosomes to regulate proliferation, differentiation, apoptosis, the immune response, inflammation, and other biological functions. Because exosomes exist widely in various body fluids, they are easy to obtain and detect and have the potential for use in disease diagnosis and prognosis detection. Exosomes can be genetically fused with targeted proteins, enhancing their biocompatibility and immunogenicity. Therefore, exosomes are the preferred vector tools for vaccines. In this review, we describe the characteristics of exosomes and discuss their unique and ambiguous functions in the immune microenvironment after infection. In this regard, we explored the ability of exosomes to carry immunogenic virus antigens and to establish adaptive immune responses. Exosomes can provide an interesting platform for antigen presentation and since vaccines are a powerful method for the prevention of infectious diseases, we further review the advantages and disadvantages of the use of exosomes in vaccine preparation. Overall, exosomes are emerging as a promising avenue for vaccine development

    Effect of urban innovation on land finance dependence: evidence from 233 Chinese cities

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    Unlike most studies on urban innovation, which focus on the effects of land-use policies, this study investigates the effect of urban innovation (UI) on land finance dependence (LFD). In China, innovation-related policies are intended to create a shared business environment where new entrepreneurs can contribute to achieving sustainable economic growth. This study analyzes the spatiotemporal dynamics of LFD and UI from 2005 to 2019 using the spatial autocorrelation model and dynamic spatial Durbin model. It finds a positive spatial association between LFD and UI throughout the studied regions during the study period. It also reveals a significant inhibitory effect of UI on LFD and a negative impact on the LFD of neighbouring cities. Moreover, the inhibitory effects will increase over time. Lastly, this study shows varied impacts of UI on LFD in different regions, especially in eastern China. Important policy recommendations for high-quality development in China are provided

    Engineered soluble ACE2 receptor: Responding to change with change

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    SARS coronavirus 2 (SARS-CoV-2) invades the human body by binding to major receptors such as ACE2 via its S-spike protein, so the interaction of receptor-binding sites has been a hot topic in the development of coronavirus drugs. At present, the clinical progress in monoclonal antibody therapy that occurred early in the pandemic is gradually showing signs of slowing. While recombinant soluble ACE2, as an alternative therapy, has been modified by many engineering methods, both the safety and functional aspects are approaching maturity, and this therapy shows great potential for broadly neutralizing coronaviruses, but its progress in clinical development remains stalled. Therefore, there are still several key problems to be considered and solved for recombinant soluble ACE2 to be approved as a clinical treatment as soon as possible

    Crop growth inhibited by over-liming in tea plantations

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    Liming is a common strategy applied to attain optimal pH for tea growth in severely acidic soils. Tea however is a calciphobous plant, and the effects of liming on its growth and nutrient uptake remain poorly understand. Therefore, it is necessary to better understand the effects of liming on soil chemical properties and tea nutrient content. In this study, a tea plantation that had exhibited large variation in growth after liming was selected as a study site. We categorized plots into two growth condition groups: Plot 1 (poor growth) and Plot 2 (excellent growth). Tea nutrient levels, and soil chemical properties were then compared between the two groups. Normalized difference vegetation index (NDVI) and transformed vegetation index (TVI) values were significantly higher and lower, respectively, in Plot 2 than in Plot 1. Yield, number of buds per m2, and 100-bud weight were significantly higher in Plot 2. These results were attributed to higher N, K, and Al concentrations and lower Ca concentrations in leaves, and lower pH and available Ca and higher available Al in soil. Leaf concentrations of K and Al were significantly negatively correlated with leaf concentrations of Ca and soil pH. A positive relationship was observed between leaf concentrations of K and Al, indicating inhibited K and Al uptake due to over-liming, restricting tea growth. In conclusion, our results show that tea growth will be restricted by over-liming, as a result of the high soil pH and Ca concentration inhibiting the K and Al uptake
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