178 research outputs found

    Development of in/outflow boundary conditions for MPM simulation of uniform and non-uniform open channel flows

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    This paper describes the development and application of inflow and outflow boundary conditions (BCs) for the material point method (MPM) in order to simulate fluid flow problems. This corresponds to velocity and pressure controlled BCs. Due to the coupled Lagrangian and Eulerian description of the fluid motion in MPM it is necessary to add and remove material points, with appropriate kinematic properties, to and from the computational domain. The newly-developed BCs have been used to simulate uniform open channel flow and the phenomenon of free overfall in open channels, which is transient conditions leading to non-uniform flow due to a sudden bed level drop. It is shown that the numerical results predict well the flow geometry including end depth ratio, pressure distribution and accelerations, therefore the velocities and displacements.Fundamental Research Funds for the Central Universities (2017B12214) of the Ministry of Education of China, NWO Project MPM-FLOW: Understanding flowslides in flood defences (Grant No. 13889

    Efficient [(18)F]AlF Radiolabeling of ZHER3:8698 Affibody Molecule for Imaging of HER3 Positive Tumors.

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    The human epidermal growth factor receptor 3 (HER3) is overexpressed in several cancers, being linked to a more resistant phenotype and hence leading to poor patient prognosis. Imaging HER3 is challenging owing to the modest receptor number (<50000 receptors/cell) in overexpressing cancer cells. Therefore, to image HER3 in vivo, high target affinity PET probes need to be developed. This work describes two different [(18)F]AlF radiolabeling strategies of the ZHER3:8698 affibody molecule specifically targeting HER3. The one-pot radiolabeling of ZHER3:8698 performed at 100 °C and using 1,4,7-triazanonane-1,4,7-triacetate (NOTA) as chelator resulted in radiolabeled products with variable purity attributed to radioconjugate thermolysis. An alternative approach based on the inverse electron demand Diels-Alder (IEDDA) reaction between a novel tetrazine functionalized 1,4,7-triazacyclononane-1,4-diacetate (NODA) chelator and the trans-cyclooctene (TCO) functionalized affibody molecule was also investigated. This method enabled the radiolabeling of the protein at room temperature. The [(18)F]AlF-NOTA-ZHER3:8698 and [(18)F]AlF-NODA-ZHER3:8698 conjugates showed a specific uptake at 1 h after injection in high HER3-expressing MCF-7 tumors of 4.36 ± 0.92% ID/g and 4.96 ± 0.65% ID/g, respectively. The current results are encouraging for further investigation of [(18)F]AlF-NOTA-ZHER3:8698 as a HER3 imaging agent

    High pressure gas flow, storage, and displacement in fractured rock-Experimental setup development and application.

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    This paper presents the design, development, and application of a laboratory setup for the experimental investigations of gas flow and reactions in a fractured rock. The laboratory facility comprises (i) a high pressure manometric sorption apparatus, where equilibrium and kinetic phenomena of adsorption and desorption can be examined, (ii) a high pressure triaxial core flooding system where the chemical reactive transport properties or processes can be explored, and (iii) an ancillary system including pure and mixed gas supply and analysis units. Underground conditions, in terms of pore pressure, confining pressure, and temperature, can be replicated using the triaxial core flooding system developed for depths up to 2 km. Core flooding experiments can be conducted under a range of gas injection pressures up to 20 MPa and temperatures up to 338 K. Details of the design considerations and the specification for the critical measuring instruments are described. The newly developed laboratory facility has been applied to study the adsorption of N2, CH4, and CO2 relevant to applications in carbon sequestration in coal and enhanced coalbed methane recovery. Under a wide range of pressures, the flow of helium in a core sample was studied and the evolution of absolute permeability at different effective stress conditions has been investigated. A comprehensive set of high resolution data has been produced on anthracite coal samples from the South Wales coalfield, using the developed apparatus. The results of the applications provide improved insight into the high pressure flow and reaction of various gas species in the coal samples from the South Wales coalfield

    Shark depredation: future directions in research and management

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    Shark depredation is a complex social-ecological issue that affects a range of fisheries worldwide. Increasing concern about the impacts of shark depredation, and how it intersects with the broader context of fisheries management, has driven recent research in this area, especially in Australia and the United States. This review synthesises these recent advances and provides strategic guidance for researchers aiming to characterise the occurrence of depredation, identify the shark species responsible, and test deterrent and management approaches to reduce its impacts. Specifically, the review covers the application of social science approaches, as well as advances in video camera and genetic methods for identifying depredating species. The practicalities and considerations for testing magnetic, electrical, and acoustic deterrent devices are discussed in light of recent research. Key concepts for the management of shark depredation are reviewed, with recommendations made to guide future research and policy development. Specific management responses to address shark depredation are lacking, and this review emphasizes that a “silver bullet” approach for mitigating depredation does not yet exist. Rather, future efforts to manage shark depredation must rely on a diverse range of integrated approaches involving those in the fishery (fishers, scientists and fishery managers), social scientists, educators, and other stakeholders

    The natural capital accounting opportunity: Let s really do the numbers

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    This work was conducted as a part of the “Accounting for U.S. Ecosystem Services at National and Subnational Scales” working group supported by the National Socio-Environmental Synthesis Center under funding received from the National Science Foundation (grant no. DBI-1052875) and the US Geological Survey John Wesley Powell Center for Analysis and Synthesis (grant no. GX16EW00ECSV00)

    Macrophage-derived IL-1β and TNF-α regulate arginine metabolism in neuroblastoma

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    © 2018 American Association for Cancer Research. Neuroblastoma is the most common childhood solid tumor, yet the prognosis for high-risk disease remains poor. We demonstrate here that arginase 2 (ARG2) drives neuroblastoma cell proliferation via regulation of arginine metabolism. Targeting arginine metabolism, either by blocking cationic amino acid transporter 1 (CAT-1)-dependent arginine uptake in vitro or therapeutic depletion of arginine by pegylated recombinant arginase BCT-100, significantly delayed tumor development and prolonged murine survival. Tumor cells polarized infiltrating monocytes to an M1-macrophage phenotype, which released IL1b and TNFa in a RAC-alpha serine/threonine-protein kinase (AKT)-dependent manner. IL1b and TNFa established a feedback loop to upregulate ARG2 expression via p38 and extracellular regulated kinases 1/2 (ERK1/2) signaling in neuroblastoma and neural crest-derived cells. Proteomic analysis revealed that enrichment of IL1b and TNFa in stage IV human tumor microenvironments was associated with a worse prognosis. These data thus describe an immune-metabolic regulatory loop between tumor cells and infiltrating myeloid cells regulating ARG2, which can be clinically exploited

    Experimental and computational studies of the production of 1,3-butadiene from 2,3-butanediol using SiO2-supported H3PO4 derivatives

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    Silica-supported phosphoric acid and metal phosphate catalyzed 1,3-butadiene (BDE) production from 2,3-butanediol (2,3-BDO) was studied using experimental and computational techniques. The catalyst was initially tested in a continuous flow reactor using commercially available 2,3-BDO, leading to maximum BDE yields of 63C%. Quantum chemical mechanistic studies revealed 1,2-epoxybutane is a kinetically viable and thermodynamically stable intermediate, supported by experimental demonstration that this epoxide can be converted to BDE under standard reaction conditions. Newly proposed E2 and SN2′ elementary steps were studied to rationalize the formation of BDE and all detected side-products. Additionally, using quantum mechanics/molecular mechanics (QM/MM) calculations, we modeled silica-supported phosphate catalysts to study the effect of the alkali metal center. Natural population analysis showed that phosphate oxygen atoms are more negatively charged in CsH2PO4/SiO2 than in H3PO4/SiO2. In combination with temperature-programmed desorption experiments using CO2, the results of this study suggest that the improved selectivity achieved when adding the metal center is related to an increase in the basicity of the catalyst.R.S.P. and J.V.A.-R. acknowledge the RMACC Summit supercomputer, supported by the NSF (ACI-1532235 and ACI1532236), and the Extreme Science and Engineering Discovery Environment (XSEDE) allocations TG-CHE180056 and TG-CHE200033. J.V.A.-R. acknowledges financial support through the Gobierno de Aragón-Fondo Social Europeo (Research Group E07_23R) and a Juan de la Cierva Incorporación contract from the Ministry of Science and Innovation (MCIN) and the State Research Agency (AEI) of Spain, and the European Union (NextGenerationEU/PRTR) under grant reference IJC2020-044217-I. S.K. acknowledges XSEDE allocation TG-CHE210034 and the National Renewable Energy Laboratory Computational Science Center. This work was authored in part by the National Renewable Energy Laboratory, managed and operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding was provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Bioenergy Technologies Office and in collaboration with the Consortium for Computational Physics and Chemistry (CCPC) and the Chemical Catalysis for Bioenergy Consortium (ChemCatBio). G.R.H., X.H., F.G.B, K.A.U., B.C.K., R.E.D., and D.R.V. acknowledge funding from the Chemical Catalysis for Bioenergy consortium by the Bioenergy Technologies Office in the DOE Office of Energy Efficiency and Renewable Energy. Microscopy was performed in collaboration with the Chemical Catalysis for Bioenergy Consortium under contract no. DE-AC05-00OR22725 with Oak Ridge National Laboratory (ORNL) and through a user project supported by ORNL’s Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Part of the microscopy research was also supported by the Office of Nuclear Energy, Fuel Cycle R&D Program and the Nuclear Science User Facilities. The results and analysis presented in this paper were partially possible thanks to the access granted to computing resources at the Galicia Supercomputing Center, CESGA, including access to the FinisTerrae supercomputer, the Red Española de Supercomputación (grant number QH-2023-1-0003) and the Drago cluster facility of SGAI-CSIC.Peer reviewe

    Potential applications of nanotechnology in thermochemical conversion of microalgal biomass

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    The rapid decrease in fossil reserves has significantly increased the demand of renewable and sustainable energy fuel resources. Fluctuating fuel prices and significant greenhouse gas (GHG) emission levels have been key impediments associated with the production and utilization of nonrenewable fossil fuels. This has resulted in escalating interests to develop new and improve inexpensive carbon neutral energy technologies to meet future demands. Various process options to produce a variety of biofuels including biodiesel, bioethanol, biohydrogen, bio-oil, and biogas have been explored as an alternative to fossil fuels. The renewable, biodegradable, and nontoxic nature of biofuels make them appealing as alternative fuels. Biofuels can be produced from various renewable resources. Among these renewable resources, algae appear to be promising in delivering sustainable energy options. Algae have a high carbon dioxide (CO2) capturing efficiency, rapid growth rate, high biomass productivity, and the ability to grow in non-potable water. For algal biomass, the two main conversion pathways used to produce biofuel include biochemical and thermochemical conversions. Algal biofuel production is, however, challenged with process scalability for high conversion rates and high energy demands for biomass harvesting. This affects the viable achievement of industrial-scale bioprocess conversion under optimum economy. Although algal biofuels have the potential to provide a sustainable fuel for future, active research aimed at improving upstream and downstream technologies is critical. New technologies and improved systems focused on photobioreactor design, cultivation optimization, culture dewatering, and biofuel production are required to minimize the drawbacks associated with existing methods. Nanotechnology has the potential to address some of the upstream and downstream challenges associated with the development of algal biofuels. It can be applied to improve system design, cultivation, dewatering, biomass characterization, and biofuel conversion. This chapter discusses thermochemical conversion of microalgal biomass with recent advances in the application of nanotechnology to enhance the development of biofuels from algae. Nanotechnology has proven to improve the performance of existing technologies used in thermochemical treatment and conversion of biomass. The different bioprocess aspects, such as reactor design and operation, analytical techniques, and experimental validation of kinetic studies, to provide insights into the application of nanotechnology for enhanced algal biofuel production are addressed

    Anaerobic digestion and gasification of seaweed

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    The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, with over 70 years of sometimes intensive research and considerable financial investment. A wide range of unit operations can be combined to produce algal biofuel, but as yet there is no successful commercial system producing such biofuel. This suggests that there are major technical and engineering difficulties to be resolved before economically viable algal biofuel production can be achieved. Both gasification and anaerobic digestion have been suggested as promising methods for exploiting bioenergy from biomass, and two major projects have been funded in the UK on the gasification and anaerobic digestion of seaweed, MacroBioCrude and SeaGas. This chapter discusses the use of gasification and anaerobic digestion of seaweed for the production of biofuel
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