1,171 research outputs found

    The Two-Phase Arterial Blood Flow with or without a Catheter and in the Presence of a Single or Multi Stenosis

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    We consider the problem of blood flow in an artery with or without a catheter and in the presence of single or multi stenosis whose shape is based on the available experimental data for the stenosis in a human’s artery. The presence of stenosis in the artery, which locally narrows portion of the artery, can be a result of fatty materials such as cholesterol in the blood. The use of catheter is important as a standard tool for diagnosis and treatment in patience whose blood flow passage in the artery is affected adversely by the presence of the stenosis within the artery. The blood flow in the arterial tube is represented by a two-phase model composing a suspension of red cells in plasma. The governing equations for both fluid (plasma) and particles (red cells) are solved subject to reasonable modeling and approximations. The important quantities such as blood velocity, blood pressure gradient, impedance (blood flow resistance), wall shear stress and its surface integrated force are computed in the presence or absence of the catheter, and, in particular, effects of the stenosis, size of the catheter’s radius and the hematocrit due to the red cells-plasma combination of the blood flow are determined

    The Two-Phase Arterial Blood Flow with or without a Catheter and in the Presence of a Single or Multi Stenosis

    Get PDF
    We consider the problem of blood flow in an artery with or without a catheter and in the presence of single or multi stenosis whose shape is based on the available experimental data for the stenosis in a human’s artery. The presence of stenosis in the artery, which locally narrows portion of the artery, can be a result of fatty materials such as cholesterol in the blood. The use of catheter is important as a standard tool for diagnosis and treatment in patience whose blood flow passage in the artery is affected adversely by the presence of the stenosis within the artery. The blood flow in the arterial tube is represented by a two-phase model composing a suspension of red cells in plasma. The governing equations for both fluid (plasma) and particles (red cells) are solved subject to reasonable modeling and approximations. The important quantities such as blood velocity, blood pressure gradient, impedance (blood flow resistance), wall shear stress and its surface integrated force are computed in the presence or absence of the catheter, and, in particular, effects of the stenosis, size of the catheter’s radius and the hematocrit due to the red cells-plasma combination of the blood flow are determined

    COVID-19 Implications for Scenarios and Modelling and Considerations Moving Forward: Perspectives from the Integrated Assessment Modelling Community

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    Presentation given at the informal virtual meeting hosted by the SBSTA Chair with representatives from the research and systematic observation community and UNFCCC constituted bodies.The event aimed to provide an opportunity for discussing the impact of the COVID-19 crisis on climate research and systematic observation, new opportunities emerging from this crisis for recovering better and what has changed and what needs to change in scientific communication on climate change

    Comparison between seasonal pumped-storage and conventional reservoir dams from the water, energy and land nexus perspective

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    Renewable sources of energy are providing an increasing share of the electricity generation mix, but their intermittency drives a need for energy storage. At the same time, water resources are increasingly scarce due to changes in demand, such as from population growth, supply side pressures such as climate change and governance challenges relating to poor management. Large storage reservoirs are used for water management and for energy storage. However, some existing and proposed hydropower reservoirs require vast areas of land and have considerable social and environmental impacts. Growing concerns on water and energy storage from a water-energy-land nexus approach motivated this study. Our objective is to compare how energy and water storage services, such as hydropower generation, electricity grid and water management, are provided with Seasonal Pumped-Storage (SPS) and Conventional Reservoir Dams (CRD) plants. Our case study region is Brazil, a country with extensive hydropower capacity and development plans, for which we compare the cost, land requirement and social impacts between CRD and potential SPS plants. Whilst seasonal pumped-storage have higher capital costs than conventional reservoir dams, given the much lower land requirements and evaporative losses, they are a valuable water and energy storage alternative especially in locations with plain topography and high evaporation. Results show that if Sobradinho CRD was built today it would result in a USD1.46billionloss,ontheotherhand,MuqueˊmSPSplantwouldresultinaUSD 1.46 billion loss, on the other hand, Muquém SPS plant would result in a USD 0.67b revenue

    Making or breaking climate targets: The AMPERE study on staged accession scenarios for climate policy

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    This study explores a situation of staged accession to a global climate policy regime from the current situation of regionally fragmented and moderate climate action. The analysis is based on scenarios in which a front runner coalition -- the EU or the EU and China -- embarks on immediate ambitious climate action while the rest of the world makes a transition to a global climate regime between 2030 and 2050. We assume that the ensuing regime involves strong mitigation efforts but does not require late joiners to compensate for their initially higher emissions. Thus, climate targets are relaxed, and although staged accession can achieve significant reductions of global warming, the resulting climate outcome is unlikely to be consistent with the goal of limiting global warming to 2 degrees. The addition of China to the front runner coalition can reduce pre-2050 excess emissions by 20.30%, increasing the likelihood of staying below 2 degrees. Not accounting for potential co-benefits, the cost of front runner action is found to be lower for the EU than for China. Regions that delay their accession to the climate regime face a trade-off between reduced short term costs and higher transitional requirements due to larger carbon lock-ins and more rapidly increasing carbon prices during the accession period

    HERMIONE: a randomized Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician's choice plus trastuzumab in patients with previously treated, anthracycline-naĂŻve, HER2-positive, locally advanced/metastatic breast cancer.

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    BackgroundHuman epidermal growth factor receptor 2 (HER2)-positive breast cancer is a particularly aggressive form of the disease, and ultimately progresses in patients with metastases on standard therapies. Anthracyclines, such as doxorubicin, are an effective treatment for HER2-positive breast cancer, particularly when administered in combination with trastuzumab - however, doxorubicin-related cardiotoxicity has limited its use. Many patients are therefore never treated with anthracyclines, even upon disease progression, despite the potential for benefit. MM-302 is a novel, HER2-targeted antibody-liposomal doxorubicin conjugate that specifically targets HER2-overexpressing cells. Preclinical and Phase 1 data suggest that MM-302, as a monotherapy or in combination with trastuzumab, could be effective for managing previously treated, anthracycline-naïve, HER2-positive breast cancer, without the cardiotoxicity observed with free doxorubicin formulations.Methods/designHERMIONE is an open-label, multicenter, randomized (1:1) Phase 2 trial of MM-302 plus trastuzumab versus chemotherapy of physician's choice (gemcitabine, capecitabine, or vinorelbine) plus trastuzumab planned to enroll 250 anthracycline-naïve patients with locally advanced/metastatic HER2-positive breast cancer. Key inclusion criteria are: previous treatment with trastuzumab (with or without pertuzumab) in any setting; refractory or intolerant to pertuzumab (refractory to pertuzumab defined as progression in the locally advanced or metastatic setting, or disease recurrence during or within 12 months of completing pertuzumab-containing neoadjuvant and/or adjuvant therapy); and disease progression on, or intolerant to, ado-trastuzumab emtansine for locally advanced or metastatic disease. The trial is currently being conducted at sites in the USA, Canada, and Western Europe. Treatment will be administered in 21-day cycles, and will be continued until disease progression or unacceptable toxicity. The primary endpoint is independently assessed progression-free survival (PFS). Tumor response will be assessed every 6 weeks, and defined according to RECIST v1.1. Secondary endpoints include investigator-assessed PFS, overall survival (OS), OS rates at 6 months and 1 year, objective response rates, safety and tolerability, quality of life, and the pharmacokinetic profile of MM-302 plus trastuzumab.DiscussionThe HERMIONE study will evaluate the efficacy and safety of MM-302 plus trastuzumab in patients with refractory HER2-positive advanced/metastatic breast cancer for whom there are no standard of care therapies with a proven survival advantage.Trial registrationClinicaltrials.gov identifier: NCT02213744 . Registration date: 06AUG2014
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