43 research outputs found

    Colloid-oil-water-interface interactions in the presence of multiple salts: charge regulation and dynamics

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    We theoretically and experimentally investigate colloid-oil-water-interface interactions of charged, sterically stabilized, poly(methyl-methacrylate) colloidal particles dispersed in a low-polar oil (dielectric constant ϵ=510\epsilon=5-10) that is in contact with an adjacent water phase. In this model system, the colloidal particles cannot penetrate the oil-water interface due to repulsive van der Waals forces with the interface whereas the multiple salts that are dissolved in the oil are free to partition into the water phase. The sign and magnitude of the Donnan potential and/or the particle charge is affected by these salt concentrations such that the effective interaction potential can be highly tuned. Both the equilibrium effective colloid-interface interactions and the ion dynamics are explored within a Poisson-Nernst-Planck theory, and compared to experimental observations.Comment: 13+2 pages, 5+3 figures; V2: small clarifications in the tex

    О финансово-экономическом кризисе

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    У статті для визначення позиції молодих учених, стосовно фінансово-економічної кризи 2008–2010 р. використаний метод нечіткої кластеризації даних, що працює в режимі паралельної їхньої обробки. Наведено заходи щодо зниження наслідків кризи для України.В статье для определения позиции молодых ученых, применительно к финансово-экономическому кризису 2008—2010 гг. использован метод нечеткой кластеризации данных, который работает в режиме параллельной их обработки. Приведены мероприятия по снижению последствий кризиса для Украины.In an article for determining the position of young scientists, in relation to financial and economic crisis, 2008— 2010. used the method of fuzzy clustering, which operates in parallel processing. Shows the measures to reduce the impact of the crisis in Ukraine

    In situ single particle characterization of the themoresponsive and co-nonsolvent behavior of PNIPAM microgels and silica@PNIPAM core-shell colloids

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    Poly(N-isopropylacrylamide) (PNIPAM) microgels and PNIPAM colloidal shells attract continuous strong interest due to their thermoresponsive behavior, as their size and properties can be tuned by temperature. The direct single particle observation and characterization of pure, unlabeled PNIPAM microgels in their native aqueous environment relies on imaging techniques that operate either at interfaces or in cryogenic conditions, thus limiting the observation of their dynamic nature. Liquid Cell (Scanning) Transmission Electron Microscopy (LC-(S) TEM) imaging allows the characterization of materials and dynamic processes such as nanoparticle growth, etching, and diffusion, at nanometric resolution in liquids. Here we show that via a facile post-synthetic in situ polymer labelling step with high-contrast marker core–shell Au@SiO2 nanoparticles (NPs) it is possible to determine the full volume of PNIPAM microgels in water. The labelling allowed for the successful characterization of the thermoresponsive behavior of PNIPAM microgels and core shell silica@PNIPAM hybrid microgels, as well as the co-nonsolvency of PNIPAM in aqueous alcoholic solutions. The interplay between electron beam irradiation and PNIPAM systems in water resulted in irreversible shrinkage due to beam induced water radiolysis products, which in turn also affected the thermoresponsive behavior of PNIPAM. The addition of 2-propanol as radical scavenger improved PNIPAM stability in water under electron beam irradiation

    Cost Analysis From a Randomized Comparison of Immediate Versus Delayed Angiography After Cardiac Arrest

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    Background In patients with out‐of‐hospital cardiac arrest without ST‐segment elevation, immediate coronary angiography did not improve clinical outcomes when compared with delayed angiography in the COACT (Coronary Angiography After Cardiac Arrest) trial. Whether 1 of the 2 strategies has benefits in terms of health care resource use and costs is currently unknown. We assess the health care resource use and costs in patients with out‐of‐hospital cardiac arrest. Methods and Results A total of 538 patients were randomly assigned to a strategy of either immediate or delayed coronary angiography. Detailed health care resource use and cost‐prices were collected from the initial hospital episode. A generalized linear model and a gamma distribution were performed. Generic quality of life was measured with the RAND‐36 and collected at 12‐month follow‐up. Overall total mean costs were similar between both groups (EUR 33 575±19 612 versus EUR 33 880±21 044; P=0.86). Generalized linear model: (β, 0.991; 95% CI, 0.894–1.099; P=0.86). Mean procedural costs (coronary angiography and percutaneous coronary intervention, coronary artery bypass graft) were higher in the immediate angiography group (EUR 4384±3447 versus EUR 3028±4220; P<0.001). Costs concerning intensive care unit and ward stay did not show any significant difference. The RAND‐36 questionnaire did not differ between both groups. Conclusions The mean total costs between patients with out‐of‐hospital cardiac arrest randomly assigned to an immediate angiography or a delayed invasive strategy were similar during the initial hospital stay. With respect to the higher invasive procedure costs in the immediate group, a strategy awaiting neurological recovery followed by coronary angiography and planned revascularization may be considered. Registration URL: https://trialregister.nl; Unique identifier: NL4857

    Sex differences in patients with out-of-hospital cardiac arrest without ST-segment elevation:A COACT trial substudy

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    Background: Whether sex is associated with outcomes of out-of-hospital cardiac arrest (OHCA) is unclear. Objectives: This study examined sex differences in survival in patients with OHCA without ST-segment elevation myocardial infarction (STEMI). Methods: Using data from the randomized controlled Coronary Angiography after Cardiac Arrest (COACT) trial, the primary point of interest was sex differences in OHCA-related one-year survival. Secondary points of interest included the benefit of immediate coronary angiography compared to delayed angiography until after neurologic recovery, angiographic and clinical outcomes. Results: In total, 522 patients (79.1% men) were included. Overall one-year survival was 59.6% in women and 63.4% in men (HR 1.18; 95% CI: 0.761.81;p = 0.47). No cardiovascular risk factors were found that modified survival. Women less often had significant coronary artery disease (CAD) (37.0% vs. 71.3%; p < 0.001), but when present, they had a worse prognosis than women without CAD (HR 3.06; 95% CI 1.31-7.19; p = 0.01). This was not the case for men (HR 1.05; 95% CI 0.67-1.65; p = 0.83). In both sexes, immediate coronary angiography did not improve one-year survival compared to delayed angiography (women, odds ratio (OR) 0.87; 95% CI 0.58-1.30;p = 0.49; vs. men, OR 0.97; 95% CI 0.45-2.09; p = 0.93). Conclusion: In OHCA patients without STEMI, we found no sex differences in overall one-year survival. Women less often had significant CAD, but when CAD was present they had worse survival than women without CAD. This was not the case for men. Both sexes did not benefit from a strategy of immediate coronary angiography as compared to delayed strategy with respect to one-year survival

    Data on sex differences in one-year outcomes of out-of-hospital cardiac arrest patients without ST-segment elevation

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    Sex differences in out-of-hospital cardiac arrest (OHCA) patients are increasingly recognized. Although it has been found that post-resuscitated women are less likely to have significant coronary artery disease (CAD) than men, data on follow-up in these patients are limited. Data for this data in brief article was obtained as a part of the randomized controlled Coronary Angiography after Cardiac Arrest without ST-segment elevation (COACT) trial. The data supplements the manuscript "Sex differences in out-of-hospital cardiac arrest patients without ST-segment elevation: A COACT trial substudy" were it was found that women were less likely to have significant CAD including chronic total occlusions, and had worse survival when CAD was present. The dataset presented in this paper describes sex differences on interventions, implantable-cardioverter defibrillator (ICD) shocks and hospitalizations due to heart failure during one-year follow-up in patients successfully resuscitated after OHCA. Data was derived through a telephone interview at one year with the patient or general practitioner. Patients in this randomized dataset reflects a homogenous study population, which can be valuable to further build on research regarding long-term sex differences and to further improve cardiac care. (C) 2020 The Authors. Published by Elsevier Inc

    Coronary Angiography After Cardiac Arrest Without ST Segment Elevation:One-Year Outcomes of the COACT Randomized Clinical Trial

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    Importance: Ischemic heart disease is a common cause of cardiac arrest. However, randomized data on long-term clinical outcomes of immediate coronary angiography and percutaneous coronary intervention (PCI) in patients successfully resuscitated from cardiac arrest in the absence of ST segment elevation myocardial infarction (STEMI) are lacking. Objective: To determine whether immediate coronary angiography improves clinical outcomes at 1 year in patients after cardiac arrest without signs of STEMI, compared with a delayed coronary angiography strategy. Design, Setting, and Participants: A prespecified analysis of a multicenter, open-label, randomized clinical trial evaluated 552 patients who were enrolled in 19 Dutch centers between January 8, 2015, and July 17, 2018. The study included patients who experienced out-of-hospital cardiac arrest with a shockable rhythm who were successfully resuscitated without signs of STEMI. Follow-up was performed at 1 year. Data were analyzed, using the intention-to-treat principle, between August 29 and October 10, 2019. Interventions: Immediate coronary angiography and PCI if indicated or coronary angiography and PCI if indicated, delayed until after neurologic recovery. Main Outcomes and Measures: Survival, myocardial infarction, revascularization, implantable cardiac defibrillator shock, quality of life, hospitalization for heart failure, and the composite of death or myocardial infarction or revascularization after 1 year. Results: At 1 year, data on 522 of 552 patients (94.6%) were available for analysis. Of these patients, 413 were men (79.1%); mean (SD) age was 65.4 (12.3) years. A total of 162 of 264 patients (61.4%) in the immediate angiography group and 165 of 258 patients (64.0%) in the delayed angiography group were alive (odds ratio, 0.90; 95% CI, 0.63-1.28). The composite end point of death, myocardial infarction, or repeated revascularization since the index hospitalization was met in 112 patients (42.9%) in the immediate group and 104 patients (40.6%) in the delayed group (odds ratio, 1.10; 95% CI, 0.77-1.56). No significant differences between the groups were observed for the other outcomes at 1-year follow-up. For example, the rate of ICD shocks was 20.4% in the immediate group and 16.2% in the delayed group (odds ratio, 1.32; 95% CI, 0.66-2.64). Conclusions and Relevance: In this trial of patients successfully resuscitated after out-of-hospital cardiac arrest and without signs of STEMI, a strategy of immediate angiography was not found to be superior to a strategy of delayed angiography with respect to clinical outcomes at 1 year. Coronary angiography in this patient group can therefore be delayed until after neurologic recovery without affecting outcomes

    Data on sex differences in one-year outcomes of out-of-hospital cardiac arrest patients without ST-segment elevation

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    Sex differences in out-of-hospital cardiac arrest (OHCA) patients are increasingly recognized. Although it has been found that post-resuscitated women are less likely to have significant coronary artery disease (CAD) than men, data on follow-up in these patients are limited. Data for this data in brief article was obtained as a part of the randomized controlled Coronary Angiography after Cardiac Arrest without ST-segment elevation (COACT) trial. The data supplements the manuscript “Sex differences in out-of-hospital cardiac arrest patients without ST-segment elevation: A COACT trial substudy” were it was found that women were less likely to have significant CAD including chronic total occlusions, and had worse survival when CAD was present. The dataset presented in this paper describes sex differences on interventions, implantable-cardioverter defibrillator (ICD) shocks and hospitalizations due to heart failure during one-year follow-up in patients successfully resuscitated after OHCA. Data was derived through a telephone interview at one year with the patient or general practitioner. Patients in this randomized dataset reflects a homogenous study population, which can be valuable to further build on research regarding long-term sex differences and to further improve cardiac care

    Climate control of terrestrial carbon exchange across biomes and continents

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    Peer reviewe

    Electric-Field-Induced Lock-and-Key Interactions between Colloidal Spheres and Bowls

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    To realize new and directed self-assembly (SA) pathways, the focus in colloid science and nanoscience has shifted from spherical particles and interactions to increasingly more complex shapes and interparticle potentials. This field is fueled by recent breakthroughs in particle synthesis, such as particles with complementary shapes that allow for specific lock-and-key interactions induced by depletants. Here, we show that electric fields form an alternative route for directing the SA of convex and concave colloids, with the additional advantage that the system now becomes switchable by external conditions. Both experimental and theoretical results are presented that validate the electric-field-induced assembly mechanism and show that even irreversibly bound composites can be generated by tuning the force balance. The successful isolation of the irreversible composite particles, in combination with generalization to different materials, shows that the current mechanism provides a versatile new path not only toward complex-particle synthesis but also toward directed self-assembly
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