Oleate

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Allan Holmgren - One of the best experts on this subject based on the ideXlab platform.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Abstract Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01–0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm−1 assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k1 = 0.030 ± 0.002 min−1. Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1–5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide.

  • Competition between sodium Oleate and sodium silicate for a silicate/Oleate modified magnetite surface studied by in-situ ATR-FTIR Spectroscopy
    Journal of colloid and interface science, 2009
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

Xiaofang Yang - One of the best experts on this subject based on the ideXlab platform.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Abstract Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01–0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm−1 assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k1 = 0.030 ± 0.002 min−1. Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1–5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide.

  • Competition between sodium Oleate and sodium silicate for a silicate/Oleate modified magnetite surface studied by in-situ ATR-FTIR Spectroscopy
    Journal of colloid and interface science, 2009
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

Payman Roonasi - One of the best experts on this subject based on the ideXlab platform.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

  • competition between sodium Oleate and sodium silicate for a silicate Oleate modified magnetite surface studied by in situ atr ftir spectroscopy
    Journal of Colloid and Interface Science, 2010
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Abstract Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01–0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm−1 assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k1 = 0.030 ± 0.002 min−1. Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1–5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide.

  • Competition between sodium Oleate and sodium silicate for a silicate/Oleate modified magnetite surface studied by in-situ ATR-FTIR Spectroscopy
    Journal of colloid and interface science, 2009
    Co-Authors: Payman Roonasi, Xiaofang Yang, Allan Holmgren
    Abstract:

    Attenuated Total Reflection (ATR) IR spectroscopy was utilized to monitor adsorption of sodium Oleate and sodium silicate onto synthetic magnetite at pH = 8.5, both individually and in a competitive manner. Oleate was adsorbed within a concentration range of 0.01-0.5 mM. It was observed that adsorption of Oleate increased linearly with increasing concentration of Oleate in solution up to a concentration of 0.1 mM. The infrared spectrum of Oleate showed a broad single band at 1535 cm(-1) assigned to the asymmetric stretching vibration of carboxylate, implying chemisorption of Oleate to the magnetite surface. The kinetics of Oleate adsorption followed a pseudo first-order reaction with an apparent rate constant of k(1) = 0.030 +/- 0.002 min(-1). Competitve adsorption of silicate and Oleate was performed either by adding silicate solution to a magnetite film initially equilibrated with 0.1 mM Oleate or adding Oleate solution to magnetite treated with silicate solutions in the concentration range 0.1-5 mM. It was shown that silicate, within reasonable time, had only minor effect on the amount of Oleate already adsorbed on magnetite. On the other hand, Oleate did not efficiently compete with silicate if the latter substance was already adsorbed on the iron oxide. (C) 2009 Elsevier Inc. All rights reserved.

Andre Brodkorb - One of the best experts on this subject based on the ideXlab platform.

  • Formation of cytotoxic α-lactalbumin / sodium Oleate complexes: Concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Nora Mary O’ Brien, Alan L. Kelly, Andre Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and sodium Oleate. However, some of the structural changes brought about by the binding of the sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • formation of cytotoxic α lactalbumin sodium Oleate complexes concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Alan L. Kelly, Nora M Obrien, Andre Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and sodium Oleate. However, some of the structural changes brought about by the binding of the sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • interactions between sodium Oleate and α lactalbumin the effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, Andre Brodkorb
    Abstract:

    Abstract Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble sodium Oleate and complexes of α-lactalbumin and sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when sodium Oleate was added up to a molar ratio of 8–11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0. The results obtained here suggest that α-lactalbumin can bind at least a 20 fold molar excess of Oleate, most likely in a non-specific manner.

Joseph J. Kehoe - One of the best experts on this subject based on the ideXlab platform.

  • Formation of cytotoxic α-lactalbumin / sodium Oleate complexes: Concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Nora Mary O’ Brien, Alan L. Kelly, Andre Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and sodium Oleate. However, some of the structural changes brought about by the binding of the sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • formation of cytotoxic α lactalbumin sodium Oleate complexes concentration and temperature effects
    International Dairy Journal, 2014
    Co-Authors: Joseph J. Kehoe, Kamila Lišková, Alan L. Kelly, Nora M Obrien, Andre Brodkorb
    Abstract:

    Abstract Cytotoxic complexes may be formed by mixing whey proteins and oleic acid or sodium Oleate. The present study investigated the kinetics of complex formation when the whey protein α-lactalbumin (α-LA) is mixed with sodium Oleate. Intrinsic fluorescence showed that the complex formed at room temperature during the mixing of α-LA and sodium Oleate. However, some of the structural changes brought about by the binding of the sodium Oleate can be reversed by dialysis, when loosely bound Oleate is removed. During dialysis, solutions with lower protein concentrations had reduced buffering capacity, and so the pH decreased more; this decrease in pH was correlated with a loss of Oleate from the complex. The cytotoxicity of all the samples produced in this study was strongly correlated with the amount of Oleate bound in the complex, confirming previous studies that suggested that oleic acid is the cytotoxic agent in the complex.

  • interactions between sodium Oleate and α lactalbumin the effect of temperature and concentration on complex formation
    Food Hydrocolloids, 2014
    Co-Authors: Joseph J. Kehoe, Andre Brodkorb
    Abstract:

    Abstract Complexes of α-lactalbumin and oleic acid have previously been shown to be cytotoxic to cancer cells. In this study oleic acid is replaced by the more soluble sodium Oleate and complexes of α-lactalbumin and sodium Oleate are formed. Dynamic light scattering results showed that there was a small linear increase in the particle size of α-lactalbumin when it was titrated with sodium Oleate. The fluorescence spectra of α-lactalbumin showed a linear increase in the emission maximum when sodium Oleate was added up to a molar ratio of 8–11 Oleate molecules per α-lactalbumin. Differential scanning calorimetry results show that the thermal unfolding of α-lactalbumin is altered by the presence of the sodium Oleate. There is a decrease in size of the endothermic peak of apo α-lactalbumin when sodium Oleate is added. The temperature at which unfolding occurred decreased for both apo and holo α-lactalbumin. FTIR measurements showed no significant effect of sodium Oleate in the amide I region of the α-lactalbumin spectrum indicating the presence of Oleate has little or no effect on the secondary structure of α-lactalbumin. The interactions between α-lactalbumin and sodium Oleate/oleic acid are pH dependent, turbidity and dynamic light scattering measurements showed that the association between the two was optimal between pH 6.0 and 8.0. The results obtained here suggest that α-lactalbumin can bind at least a 20 fold molar excess of Oleate, most likely in a non-specific manner.