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Eduardo J M Filipe - One of the best experts on this subject based on the ideXlab platform.
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from nano emulsions to phase separation evidence of nano segregation in alkane perfluoroalkane mixtures using 129xe nmr spectroscopy
Physical Chemistry Chemical Physics, 2019Co-Authors: Pedro Morgado, Luis F G Martins, Eduardo J M FilipeAbstract:In this work we demonstrate that mixtures of (hexane + Perfluorohexane) above the upper critical solution temperature segregate by forming domains at the nanometric scale. 129Xe NMR spectra obtained for solutions of xenon in liquid mixtures of (hexane + Perfluorohexane) as a function of temperature suggest the existence of domains richer in the hydrogenated component, in which xenon “prefers” to be solvated. The average local concentration within the xenon coordination sphere is at least 0.05 higher in hexane mole fraction than the nominal concentration of the mixture. Atomistic molecular dynamics simulations support this analysis in excellent agreement with the experimental data. Additionally, 129Xe NMR spectra in pure perfluoroalkanes allow a detailed analysis of the liquid structure, continuing that previously reported for the liquid alkanes. It should be emphasised that nano-segregation is here observed in fluids governed exclusively by dispersion interactions, in contrast to other examples in which hydrogen bonding and polarity play important roles. Given its simplicity, this case study is thus prone to have a general impact in understanding the early mechanisms of segregation, phase separation and self-assembly.
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viscosity of liquid systems involving hydrogenated and fluorinated substances liquid mixtures of hexane Perfluorohexane
Fluid Phase Equilibria, 2013Co-Authors: Pedro Morgado, Clare Mccabe, Jana E Black, Ben J Lewis, Christopher R Iacovella, Luis F G Martins, Eduardo J M FilipeAbstract:Abstract The viscosity of (hexane + Perfluorohexane) mixtures has been measured at 298 K, 303 K and 308 K, over the whole composition range. The results show large negative deviations from the arithmetic mean of the viscosities of the pure components, reaching −17% at x(Perfluorohexane) = 0.7. To obtain molecular level insight into the behaviour of the system, all-atom molecular dynamics simulations have been performed and used to calculate the viscosities, radial distribution functions, and rotational relaxation times of the studied (hexane + Perfluorohexane) mixtures. This is the first effort to assess the effect of mixing hydrogenated and fluorinated molecules in the viscosity.
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predicting the solubility of xenon in n hexane and n Perfluorohexane a simulation and theoretical study
Molecular Physics, 2002Co-Authors: Rui P Bonifacio, Clare Mccabe, Eduardo J M Filipe, Margarida Costa F Gomes, Agilio A H PaduaAbstract:The solubility of xenon in n-hexane and n-Perfluorohexane has been studied using both molecular simulation and a version of the SAFT approach (SAFT-VR). The calculations were performed close to the saturation line of each solvent, between 200 K and 450 K, which exceeds the smaller temperature range where experimental data are available in the literature. Molecular dynamics simulations, associated with Widom's test particle insertion method, were used to calculate the residual chemical potential of xenon in n-hexane and n-Perfluorohexane and the corresponding Henry's law coefficients. The simulation results overestimate the solubility of xenon in both solvents when simple geometric combining rules are used, but are in good agreement if a binary interaction parameter is included. With the SAFT-VR approach we are able to reproduce the experimental solubility for xenon in n-hexane, using simple Lorentz-Berthelot rules to describe the unlike interaction. In the case of n-Perfluorohexane as a solvent, a binary ...
Pedro Morgado - One of the best experts on this subject based on the ideXlab platform.
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from nano emulsions to phase separation evidence of nano segregation in alkane perfluoroalkane mixtures using 129xe nmr spectroscopy
Physical Chemistry Chemical Physics, 2019Co-Authors: Pedro Morgado, Luis F G Martins, Eduardo J M FilipeAbstract:In this work we demonstrate that mixtures of (hexane + Perfluorohexane) above the upper critical solution temperature segregate by forming domains at the nanometric scale. 129Xe NMR spectra obtained for solutions of xenon in liquid mixtures of (hexane + Perfluorohexane) as a function of temperature suggest the existence of domains richer in the hydrogenated component, in which xenon “prefers” to be solvated. The average local concentration within the xenon coordination sphere is at least 0.05 higher in hexane mole fraction than the nominal concentration of the mixture. Atomistic molecular dynamics simulations support this analysis in excellent agreement with the experimental data. Additionally, 129Xe NMR spectra in pure perfluoroalkanes allow a detailed analysis of the liquid structure, continuing that previously reported for the liquid alkanes. It should be emphasised that nano-segregation is here observed in fluids governed exclusively by dispersion interactions, in contrast to other examples in which hydrogen bonding and polarity play important roles. Given its simplicity, this case study is thus prone to have a general impact in understanding the early mechanisms of segregation, phase separation and self-assembly.
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viscosity of liquid systems involving hydrogenated and fluorinated substances liquid mixtures of hexane Perfluorohexane
Fluid Phase Equilibria, 2013Co-Authors: Pedro Morgado, Clare Mccabe, Jana E Black, Ben J Lewis, Christopher R Iacovella, Luis F G Martins, Eduardo J M FilipeAbstract:Abstract The viscosity of (hexane + Perfluorohexane) mixtures has been measured at 298 K, 303 K and 308 K, over the whole composition range. The results show large negative deviations from the arithmetic mean of the viscosities of the pure components, reaching −17% at x(Perfluorohexane) = 0.7. To obtain molecular level insight into the behaviour of the system, all-atom molecular dynamics simulations have been performed and used to calculate the viscosities, radial distribution functions, and rotational relaxation times of the studied (hexane + Perfluorohexane) mixtures. This is the first effort to assess the effect of mixing hydrogenated and fluorinated molecules in the viscosity.
Luis F G Martins - One of the best experts on this subject based on the ideXlab platform.
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from nano emulsions to phase separation evidence of nano segregation in alkane perfluoroalkane mixtures using 129xe nmr spectroscopy
Physical Chemistry Chemical Physics, 2019Co-Authors: Pedro Morgado, Luis F G Martins, Eduardo J M FilipeAbstract:In this work we demonstrate that mixtures of (hexane + Perfluorohexane) above the upper critical solution temperature segregate by forming domains at the nanometric scale. 129Xe NMR spectra obtained for solutions of xenon in liquid mixtures of (hexane + Perfluorohexane) as a function of temperature suggest the existence of domains richer in the hydrogenated component, in which xenon “prefers” to be solvated. The average local concentration within the xenon coordination sphere is at least 0.05 higher in hexane mole fraction than the nominal concentration of the mixture. Atomistic molecular dynamics simulations support this analysis in excellent agreement with the experimental data. Additionally, 129Xe NMR spectra in pure perfluoroalkanes allow a detailed analysis of the liquid structure, continuing that previously reported for the liquid alkanes. It should be emphasised that nano-segregation is here observed in fluids governed exclusively by dispersion interactions, in contrast to other examples in which hydrogen bonding and polarity play important roles. Given its simplicity, this case study is thus prone to have a general impact in understanding the early mechanisms of segregation, phase separation and self-assembly.
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viscosity of liquid systems involving hydrogenated and fluorinated substances liquid mixtures of hexane Perfluorohexane
Fluid Phase Equilibria, 2013Co-Authors: Pedro Morgado, Clare Mccabe, Jana E Black, Ben J Lewis, Christopher R Iacovella, Luis F G Martins, Eduardo J M FilipeAbstract:Abstract The viscosity of (hexane + Perfluorohexane) mixtures has been measured at 298 K, 303 K and 308 K, over the whole composition range. The results show large negative deviations from the arithmetic mean of the viscosities of the pure components, reaching −17% at x(Perfluorohexane) = 0.7. To obtain molecular level insight into the behaviour of the system, all-atom molecular dynamics simulations have been performed and used to calculate the viscosities, radial distribution functions, and rotational relaxation times of the studied (hexane + Perfluorohexane) mixtures. This is the first effort to assess the effect of mixing hydrogenated and fluorinated molecules in the viscosity.
Clare Mccabe - One of the best experts on this subject based on the ideXlab platform.
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viscosity of liquid systems involving hydrogenated and fluorinated substances liquid mixtures of hexane Perfluorohexane
Fluid Phase Equilibria, 2013Co-Authors: Pedro Morgado, Clare Mccabe, Jana E Black, Ben J Lewis, Christopher R Iacovella, Luis F G Martins, Eduardo J M FilipeAbstract:Abstract The viscosity of (hexane + Perfluorohexane) mixtures has been measured at 298 K, 303 K and 308 K, over the whole composition range. The results show large negative deviations from the arithmetic mean of the viscosities of the pure components, reaching −17% at x(Perfluorohexane) = 0.7. To obtain molecular level insight into the behaviour of the system, all-atom molecular dynamics simulations have been performed and used to calculate the viscosities, radial distribution functions, and rotational relaxation times of the studied (hexane + Perfluorohexane) mixtures. This is the first effort to assess the effect of mixing hydrogenated and fluorinated molecules in the viscosity.
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measurement and prediction of high pressure vapor liquid equilibria for binary mixtures of carbon dioxide n octane methanol ethanol and Perfluorohexane
Journal of Supercritical Fluids, 2010Co-Authors: Katsumi Tochigi, Hiroyuki Matsuda, Kiyofumi Kurihara, Tooru Namae, Tooru Suga, Carolina Dos M Ramos, Clare MccabeAbstract:Abstract We report the measurement of high-pressure vapor–liquid equilibrium data for binary mixtures of carbon dioxide + n -octane, +methanol, and +ethanol systems at 313.14 K and carbon dioxide + Perfluorohexane at 303.15–323.15 K. The experimental data were collected using a new simple apparatus for measuring high-pressure vapor–liquid equilibria and correlated using a modified SRK equation with the three-parameter conventional mixing rule proposed by Adachi and Sugie. The SAFT-VR equation of state has also been used to predict the phase behavior and found to be in good agreement with experimental data. For the carbon dioxide + methanol, carbon dioxide + ethanol and carbon dioxide + perfluorhexane systems simple Lorentz–Berthelot combining rules can be used to determine the cross interactions and predict the phase behavior. For the carbon dioxide + n -octane system cross interaction parameters fitted to experimental data are needed in order to capture the non-ideal phase behavior exhibited by this system.
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predicting the solubility of xenon in n hexane and n Perfluorohexane a simulation and theoretical study
Molecular Physics, 2002Co-Authors: Rui P Bonifacio, Clare Mccabe, Eduardo J M Filipe, Margarida Costa F Gomes, Agilio A H PaduaAbstract:The solubility of xenon in n-hexane and n-Perfluorohexane has been studied using both molecular simulation and a version of the SAFT approach (SAFT-VR). The calculations were performed close to the saturation line of each solvent, between 200 K and 450 K, which exceeds the smaller temperature range where experimental data are available in the literature. Molecular dynamics simulations, associated with Widom's test particle insertion method, were used to calculate the residual chemical potential of xenon in n-hexane and n-Perfluorohexane and the corresponding Henry's law coefficients. The simulation results overestimate the solubility of xenon in both solvents when simple geometric combining rules are used, but are in good agreement if a binary interaction parameter is included. With the SAFT-VR approach we are able to reproduce the experimental solubility for xenon in n-hexane, using simple Lorentz-Berthelot rules to describe the unlike interaction. In the case of n-Perfluorohexane as a solvent, a binary ...
Thea Koch - One of the best experts on this subject based on the ideXlab platform.
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effect of Perfluorohexane on the expression of cellular adhesion molecules and surfactant protein a in human mesothelial cells in vitro
Artificial Cells Blood Substitutes and Biotechnology, 2011Co-Authors: Dirk Haufe, Klaus G Dahmen, Oliver Tiebel, Matthias Hubler, Thea KochAbstract:Abstract: The intraperitoneal instillation of perfluorocarbons augmented systemic oxygenation and was protective in mesenteric ischemia-reperfusion and experimental lung injury. To study biocompatibility and potential anti-inflammatory effects of intraperitoneal perfluorocarbons, we evaluated the influence of Perfluorohexane and/or inflammatory stimuli on human mesothelial cells in vitro. Perfluorohexane exposure neither impaired cell viability nor induced cellular activation. TNFα enhanced ICAM-1 expression, which was not attenuated by simultaneous Perfluorohexane treatment. Concentration of intracellular surfactant protein A tended to be higher in Perfluorohexane treated cells compared to controls. Our in vitro data add further evidence that intraperitoneal perfluorocarbon application is feasible without adverse local effects.
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effects of Perfluorohexane vapor in the treatment of experimental lung injury
Pulmonary Pharmacology & Therapeutics, 2010Co-Authors: Jorg U Bleyl, Matthias Hubler, Marcelo Gama De Abreu, Peter M Spieth, Axel R Heller, Manuel Heintz, Matthias Schlemmer, Roland Koch, Thea KochAbstract:Abstract Rationale We investigated the effects of vaporized Perfluorohexane (PFH) on pulmonary vascular tone, pulmonary vascular resistance and peak inspiratory pressure as well as lipid mediator formation in the treatment of calcium ionophore induced lung injury in a model of the isolated perfused and ventilated rabbit lungs. Methods Lung injury was induced in isolated perfused and ventilated rabbit lungs by calcium ionophore A23187. Lungs were treated with either 4.5 vol.% (4.5 vol.% PFH; n = 6) or 18 vol.% (18 vol.% PFH; n = 6) PFH. Six lungs remained untreated (Control). In addition 5 lungs (PFH-sham) remained uninjured receiving 18 vol.% PFH only. Mean pulmonary artery pressure (mPAP), peak inspiratory pressure ( P max ), and lung weight (weight) were monitored for 120 min. Experiments were terminated before when the increase in lung weight exceeded 40 g. Perfusate samples were taken at regular intervals for analysis of TXB 2 , 6-keto-PGF 1 and LTB 4 . Results Controls reached the study end point significantly earlier than both PFH groups. Significant differences were found for a weight gain of 10 g and 20 g between the control and the 4.5 vol.% PFH and the 18 vol.% PFH. Differences in mPAP were more pronounced in the 4.5 vol.% PFH. However increases in P max were more marked in 4.5 vol.% PFH. TXA 2 -, PGI 2 -, and LTB 4 -levels were significantly lower in PFH groups. Uninjured lungs remained unaffected by the presence of 18 vol.% PFH. Conclusion Inflammatory lung injury was attenuated by the treatment with 4.5 vol.% PFH and 18 vol.% PFH vapor in the isolated perfused rabbit lung. Therapeutic effects were more pronounced with a concentration of 4.5 vol.% PFH.
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effects of vaporized Perfluorohexane and partial liquid ventilation on regional distribution of alveolar damage in experimental lung injury
Intensive Care Medicine, 2007Co-Authors: Peter M Spieth, Matthias Hubler, Thea Koch, Lilla Knels, Michael Kasper, Andre Domingues Quelhas, Barbel Wiedemann, Amelie Lupp, Antonio Giannella Neto, Marcelo Gama De AbreuAbstract:Objective To determine whether the patterns of distribution of histological effects of vaporized Perfluorohexane (PFH) and partial liquid ventilation (PLV) differ significantly in acute lung injury.
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vaporized Perfluorohexane attenuates ventilator induced lung injury in isolated perfused rabbit lungs
Anesthesiology, 2005Co-Authors: Marcelo Gama De Abreu, Matthias Hubler, Beate Wilmink, Thea KochAbstract:Background: The authors tested the hypothesis that administration of vaporized Perfluorohexane may attenuate ventilator-induced lung injury. Methods: In isolated, perfused rabbit lungs, airway pressure-versus-time curves were recorded. At baseline, peak inspiratory pressure and positive end-expiratory pressure of mechanically ventilated lungs were set to obtain straight pressure-versus-time curves in both the lower and upper ranges, which are associated with less collapse and overdistension, respectively. After that, peak inspiratory pressure and positive end-expiratory pressure were set at 30 cm H 2 O and 0, respectively, and animals were randomly assigned to one of two groups: (1) simultaneous administration of 14% Perfluorohexane vapor in room air (n = 7) and (2) control group-ventilation with room air (n = 7). After 20 min of cycling collapse and overdistension, tidal volume and positive end-expiratory pressure were set back to baseline levels, administration of Perfluorohexane in the therapy group was stopped, and mechanical ventilation was continued for up to 60 min. Lung weight, mean pulmonary artery pressure, and concentration of thromboxane B 2 in the perfusate were measured. In addition, the distribution of pulmonary perfusate flow was assessed by using fluorescent-labeled microspheres. Results: Significantly higher peak inspiratory values developed in control lungs than in lungs treated with Perfluorohexane. In addition, upper ranges of pressure-versus-time curves were closer to straight lines in the Perfluorohexane group. Lung weight, mean pulmonary arterial pressure, and release of thromboxane B 2 were significantly higher in controls than in Perfluorohexane-treated lungs. Also, redistribution of pulmonary perfusate flow from caudal to cranial zones was less important in the treatment group. Conclusion: The authors conclude that the administration of Perfluorohexane vapor attenuates the development of ventilator-induced lung injury in isolated, perfused rabbit lungs.
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Perfluorohexane attenuates proinflammatory and procoagulatory response of activated monocytes and alveolar macrophages
Anesthesiology, 2001Co-Authors: Thea Koch, Dirk Haufe, M Ragaller, A Hofer, Marianne Grosser, D M Albrecht, Matthias Kotzsch, Thomas LutherAbstract:BACKGROUND A number of studies have demonstrated the effectiveness of liquid ventilation with perfluorocarbons in improving pulmonary function in acute respiratory distress syndrome. Although it is known that perfluorocarbon-associated gas exchange facilitates lung mechanics and oxygenation, the complete mechanism by which perfluorocarbons exert their beneficial effects in acute lung injury still remains unclear. Possibly, an influence of perfluorocarbons on proinflammatory and procoagulant features of monocytic cells present in the alveolar space, such as alveolar macrophages (AMs), may be involved. Therefore, we examined in an in vitro model the effects of perfluorocarbon on both activated mononuclear blood cells (MBCs) and AMs by monitoring the expression of interleukin (IL)-1 beta, tumor necrosis factor (TNF)alpha, and tissue factor (TF). METHODS Mononuclear blood cells, obtained from peripheral blood of healthy volunteers, or AMs from diagnostic bronchoalveolar lavage were stimulated by incubation with lipopolysaccharide in the presence of different amounts of Perfluorohexane, which was devoid of cytotoxicity. RESULTS Using both video-enhanced contrast and electron microscopy, the authors observed that Perfluorohexane droplets were phagocytosed by activated monocytes as well as by in vitro--cultured AMs within 1--3 h. After lipopolysaccharide stimulation of monocytes or AMs, we observed a down-regulation of TF mRNA and a significant inhibition (P < 0.05) of cellular TF antigen by Perfluorohexane. In addition, the concentration of both IL-1 beta and TNF alpha in the supernatant of lipopolysaccharide-stimulated MBC was significantly decreased (P < 0.01) by Perfluorohexane compared with controls without Perfluorohexane. By preincubation of lipopolysaccharide-containing medium with Perfluorohexane, the authors could exclude that the inhibitory effect of Perfluorohexane was caused by binding or sequestering limited amounts of lipopolysaccharide. CONCLUSION Taken together, our results demonstrate an interference of Perfluorohexane with the expression of the procoagulant protein TF on monocytes and AMs as well as with the release of proinflammatory cytokines by MBCs. These effects may contribute to the protective role of liquid ventilation with perfluorocarbons in injuries associated with local activation of inflammatory processes.