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Pannuru Venkatesu - One of the best experts on this subject based on the ideXlab platform.

  • Thermophysical Properties of Aqueous Solution of Ammonium-Based Ionic Liquids
    The journal of physical chemistry. B, 2014
    Co-Authors: Reddicherla Umapathi, Pankaj Attri, Pannuru Venkatesu
    Abstract:

    Experimental densities (ρ), ultrasonic sound velocities (u), viscosities (η), and refractive indices (nD) of binary mixtures of ammonium-based ionic liquids (ILs) such as Diethylammonium acetate (DEAA) [(CH3CH2)2NH][CH3COO], triethylammonium acetate (TEAA) [(CH3CH2)3NH][CH3COO], Diethylammonium hydrogen sulfate (DEAS) [(CH3CH2)2NH][HSO4], triethylammonium hydrogen sulfate (TEAS) [(CH3CH2)3NH][HSO4], trimethylammonium acetate (TMAA) [(CH3)3NH][CH3COO], and trimethylammonium hydrogen sulfate (TMAS) [(CH3)3NH][HSO4] with water are reported over the wide composition range at 25 °C under atmospheric pressure. The excess molar volumes (VE), deviation in isentropic compressibilities (Δκs), deviation in viscosities (Δη) and deviation in refractive indices (ΔnD) are calculated from experimental values and are correlated by Redlich–Kister polynomial equations. The VE and Δκs values for the aforesaid systems are negative over the entire composition range while the Δη and ΔnD values are positive under the same experi...

  • The solubility and stability of amino acids in biocompatible ionic liquids.
    Protein and peptide letters, 2013
    Co-Authors: T. Vasantha, Pankaj Attri, Pannuru Venkatesu, Awanish Kumar, R.s. Rama Devi
    Abstract:

    In recent years, ionic liquids (ILs) represent a new class of biocompatible co-solvents for biomolecules. In this work, we report the apparent transfer free energies (ΔG'tr) for six amino acids (AA) from water to aqueous solutions of six ammonium based ILs (Diethylammonium acetate (DEAA), Diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of ΔG'tr for AA from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the obtained results, we found that the selected ammonium based ILs act as stabilizers for the structure of AA.

  • Influence of biocompatible ammonium ionic liquids on the solubility of l-alanine and l-valine in water
    Fluid Phase Equilibria, 2012
    Co-Authors: T. Vasantha, Pankaj Attri, Pannuru Venkatesu, Awanish Kumar, R.s. Rama Devi
    Abstract:

    Abstract Understanding the folding process of proteins or polypeptides in co-solvents is a fascinating and critical issue in biophysical chemistry. In recent years, ionic liquids (ILs) represent a versatility of the new class of co-solvents. To quantify the bimolecular interactions of amino acids (AA), such as l -alanine (Ala) and l -valine (Val) with biocompatible ILs, we report the apparent transfer free energies ( Δ G ′ t r ) for AA from water to aqueous solutions of six ammonium based ILs (Diethylammonium acetate (DEAA), Diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of Δ G ′ t r for Ala and Val from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the solubility results, we envisage that the selected ammonium based-ILs provide stability to the structure of AA. Further, the stability of AA has been studied by means of the UV–vis spectroscopy.

  • Temperature dependence measurements and molecular interactions for ammonium ionic liquid with N-methyl-2-pyrrolidone
    The Journal of Chemical Thermodynamics, 2012
    Co-Authors: T. Kavitha, Pankaj Attri, Pannuru Venkatesu, R.s. Rama Devi, Tadeusz Hofman
    Abstract:

    Abstract We report the synthesis and characterisation of a series of ammonium ionic liquids (ILs) containing acetate and sulphate anions with alkyl ammonium cation. To understand the thermophysical properties of these synthesised ILs with polar solvent N-methyl-2-pyrrolidone (NMP), precise measurements such as densities (ρ), speed of sound (u), and viscosity (η) over the entire mole fraction range have been measured at 5 K intervals within the temperature range of (298.15 to 313.15) K under atmospheric pressure. The excess molar volume (VE), the deviation in isentropic compressibility (Δκs), and deviation in viscosity (Δη) were predicted using these temperature dependence properties as a function of the concentration of ILs. The Redlich–Kister polynomial was used to correlate the results. The ILs investigated in the present work included Diethylammonium acetate (DEAA) [(CH3CH2)2NH][CH3COO], triethylammonium acetate (TEAA) [(CH3CH2)3NH][CH3COO], Diethylammonium hydrogen sulphate (DEAS) [(CH3CH2)2NH][HSO4], and triethylammonium hydrogen sulphate (TEAS) [(CH3CH2)3NH][HSO4]. The intermolecular interactions and structural effects were analysed on the basis of the measured and the derived properties. The information reported here in terms of ion–dipole interactions, ion-pair interactions and hydrogen bonding between ILs and NMP, elucidates the influences of ions and also the temperature effects on the thermophysical properties.

  • Thermodynamic characterization of the biocompatible ionic liquid effects on protein model compounds and their functional groups
    Physical chemistry chemical physics : PCCP, 2011
    Co-Authors: Pankaj Attri, Pannuru Venkatesu
    Abstract:

    The stability of proteins under co-solvent conditions is dependant on the nature of the co-solvent; the co-solvent can alter a protein’s properties and structural effects through bimolecular interactions between its functional groups and co-solvent particles. Ionic liquids (ILs) represent a rather diverse class of co-solvents that are combinations of different ions, which are liquids at or close to room temperature. To quantify the bimolecular interactions of protein functional groups with biocompatible ILs, we report the systematic and quantitative apparent transfer free energies (ΔG′tr) of a homologous series of cyclic dipeptides (CDs) from water to aqueous solutions of ILs through solubility measurements, as a function of IL concentration at 25 °C under atmospheric pressure. The materials investigated in the present work included the CDs of cyclo(Gly-Gly), cyclo(Ala-Gly), cyclo(Ala-Ala), cyclo(Leu-Ala), and cyclo(Val-Val). The ILs used such as Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium acetate ([Et3NH][CH3COO], TEAA), Diethylammonium dihydogen phosphate ([Et3NH][H2PO4], DEAP), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), Diethylammonium sulfate ([Et3NH][HSO4], DEAS) and triethylammonium sulfate ([Et3NH][HSO4], TEAS). We observed positive values of ΔG′tr for CDs from water to ILs, indicating that interactions between ILs and CDs are unfavourable, which leads to stabilization of the native structure of CDs. The experimental results were further used for estimating the transfer free energies (Δg′tr) of the peptide bond (–CONH–), the peptide backbone unit (–CH2CONH–), and various functional groups from water to IL solutions. Our results explicitly elucidate that a series of all ammonium ILs act as stabilizers for tested model compounds through the exclusion of ILs from CDs surface.

Pankaj Attri - One of the best experts on this subject based on the ideXlab platform.

  • Thermophysical Properties of Aqueous Solution of Ammonium-Based Ionic Liquids
    The journal of physical chemistry. B, 2014
    Co-Authors: Reddicherla Umapathi, Pankaj Attri, Pannuru Venkatesu
    Abstract:

    Experimental densities (ρ), ultrasonic sound velocities (u), viscosities (η), and refractive indices (nD) of binary mixtures of ammonium-based ionic liquids (ILs) such as Diethylammonium acetate (DEAA) [(CH3CH2)2NH][CH3COO], triethylammonium acetate (TEAA) [(CH3CH2)3NH][CH3COO], Diethylammonium hydrogen sulfate (DEAS) [(CH3CH2)2NH][HSO4], triethylammonium hydrogen sulfate (TEAS) [(CH3CH2)3NH][HSO4], trimethylammonium acetate (TMAA) [(CH3)3NH][CH3COO], and trimethylammonium hydrogen sulfate (TMAS) [(CH3)3NH][HSO4] with water are reported over the wide composition range at 25 °C under atmospheric pressure. The excess molar volumes (VE), deviation in isentropic compressibilities (Δκs), deviation in viscosities (Δη) and deviation in refractive indices (ΔnD) are calculated from experimental values and are correlated by Redlich–Kister polynomial equations. The VE and Δκs values for the aforesaid systems are negative over the entire composition range while the Δη and ΔnD values are positive under the same experi...

  • The solubility and stability of amino acids in biocompatible ionic liquids.
    Protein and peptide letters, 2013
    Co-Authors: T. Vasantha, Pankaj Attri, Pannuru Venkatesu, Awanish Kumar, R.s. Rama Devi
    Abstract:

    In recent years, ionic liquids (ILs) represent a new class of biocompatible co-solvents for biomolecules. In this work, we report the apparent transfer free energies (ΔG'tr) for six amino acids (AA) from water to aqueous solutions of six ammonium based ILs (Diethylammonium acetate (DEAA), Diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of ΔG'tr for AA from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the obtained results, we found that the selected ammonium based ILs act as stabilizers for the structure of AA.

  • Influence of biocompatible ammonium ionic liquids on the solubility of l-alanine and l-valine in water
    Fluid Phase Equilibria, 2012
    Co-Authors: T. Vasantha, Pankaj Attri, Pannuru Venkatesu, Awanish Kumar, R.s. Rama Devi
    Abstract:

    Abstract Understanding the folding process of proteins or polypeptides in co-solvents is a fascinating and critical issue in biophysical chemistry. In recent years, ionic liquids (ILs) represent a versatility of the new class of co-solvents. To quantify the bimolecular interactions of amino acids (AA), such as l -alanine (Ala) and l -valine (Val) with biocompatible ILs, we report the apparent transfer free energies ( Δ G ′ t r ) for AA from water to aqueous solutions of six ammonium based ILs (Diethylammonium acetate (DEAA), Diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of Δ G ′ t r for Ala and Val from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the solubility results, we envisage that the selected ammonium based-ILs provide stability to the structure of AA. Further, the stability of AA has been studied by means of the UV–vis spectroscopy.

  • Temperature dependence measurements and molecular interactions for ammonium ionic liquid with N-methyl-2-pyrrolidone
    The Journal of Chemical Thermodynamics, 2012
    Co-Authors: T. Kavitha, Pankaj Attri, Pannuru Venkatesu, R.s. Rama Devi, Tadeusz Hofman
    Abstract:

    Abstract We report the synthesis and characterisation of a series of ammonium ionic liquids (ILs) containing acetate and sulphate anions with alkyl ammonium cation. To understand the thermophysical properties of these synthesised ILs with polar solvent N-methyl-2-pyrrolidone (NMP), precise measurements such as densities (ρ), speed of sound (u), and viscosity (η) over the entire mole fraction range have been measured at 5 K intervals within the temperature range of (298.15 to 313.15) K under atmospheric pressure. The excess molar volume (VE), the deviation in isentropic compressibility (Δκs), and deviation in viscosity (Δη) were predicted using these temperature dependence properties as a function of the concentration of ILs. The Redlich–Kister polynomial was used to correlate the results. The ILs investigated in the present work included Diethylammonium acetate (DEAA) [(CH3CH2)2NH][CH3COO], triethylammonium acetate (TEAA) [(CH3CH2)3NH][CH3COO], Diethylammonium hydrogen sulphate (DEAS) [(CH3CH2)2NH][HSO4], and triethylammonium hydrogen sulphate (TEAS) [(CH3CH2)3NH][HSO4]. The intermolecular interactions and structural effects were analysed on the basis of the measured and the derived properties. The information reported here in terms of ion–dipole interactions, ion-pair interactions and hydrogen bonding between ILs and NMP, elucidates the influences of ions and also the temperature effects on the thermophysical properties.

  • Thermodynamic characterization of the biocompatible ionic liquid effects on protein model compounds and their functional groups
    Physical chemistry chemical physics : PCCP, 2011
    Co-Authors: Pankaj Attri, Pannuru Venkatesu
    Abstract:

    The stability of proteins under co-solvent conditions is dependant on the nature of the co-solvent; the co-solvent can alter a protein’s properties and structural effects through bimolecular interactions between its functional groups and co-solvent particles. Ionic liquids (ILs) represent a rather diverse class of co-solvents that are combinations of different ions, which are liquids at or close to room temperature. To quantify the bimolecular interactions of protein functional groups with biocompatible ILs, we report the systematic and quantitative apparent transfer free energies (ΔG′tr) of a homologous series of cyclic dipeptides (CDs) from water to aqueous solutions of ILs through solubility measurements, as a function of IL concentration at 25 °C under atmospheric pressure. The materials investigated in the present work included the CDs of cyclo(Gly-Gly), cyclo(Ala-Gly), cyclo(Ala-Ala), cyclo(Leu-Ala), and cyclo(Val-Val). The ILs used such as Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium acetate ([Et3NH][CH3COO], TEAA), Diethylammonium dihydogen phosphate ([Et3NH][H2PO4], DEAP), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), Diethylammonium sulfate ([Et3NH][HSO4], DEAS) and triethylammonium sulfate ([Et3NH][HSO4], TEAS). We observed positive values of ΔG′tr for CDs from water to ILs, indicating that interactions between ILs and CDs are unfavourable, which leads to stabilization of the native structure of CDs. The experimental results were further used for estimating the transfer free energies (Δg′tr) of the peptide bond (–CONH–), the peptide backbone unit (–CH2CONH–), and various functional groups from water to IL solutions. Our results explicitly elucidate that a series of all ammonium ILs act as stabilizers for tested model compounds through the exclusion of ILs from CDs surface.

Marcos Marques Da Silva Paula - One of the best experts on this subject based on the ideXlab platform.

  • inflammatory cytokines content in achilles tendinopathy after phonophoresis treatment combined with gold nanoparticles and diclophenac Diethylammonium in rats
    Inflammation, 2015
    Co-Authors: Marcelo B Dohnert, Gabriela K Ferreira, Paulo Cesar Lock Silveira, Elton Torres Zanoni, Luciana H Dohnert, Claudio T De Souza, Marcos Marques Da Silva Paula
    Abstract:

    Tendinitis is a painful condition that occurs in tendons in response to repetitive use or direct trauma. The therapeutic approaches commonly employed to modulate inflammation have not achieved complete success in chronic cases of tendinitis. In this scenario, considering the anti-inflammatory properties of pulsed therapeutic ultrasound and gold nanoparticles (GNPs), this study assesses the possible therapeutic effects of phonophoresis in association with diclophenac Diethylammonium and GNPs by measuring the inflammatory parameters interleukin 1β and tumor necrosis factor alpha in acute tendinous injury. Wistar rats were randomly divided into three groups and were treated with phonophoresis and diclophenac Diethylammonium, GNP gel, and a combination thereof. A significant decrease in interleukin 1β and tumor necrosis factor alpha occurred in tendons treated with phonophoresis + diclophenac + GNPs. The content of both cytokines were similar after combined treatment with phonophoresis + diclophenac + GNPs. Apart from the anti-inflammatory effect, GNPs transported and enhanced drug action when used with phonophoresis.

  • Gold nanoparticles and diclofenac Diethylammonium administered by iontophoresis reduce inflammatory cytokines expression in Achilles tendinitis
    International journal of nanomedicine, 2012
    Co-Authors: Marcelo B Dohnert, Luciana H Dohnert, Claudio T De Souza, Marcos Marques Da Silva Paula, Mirelli Venâncio, Jonathann Corrêa Possato, Rodrigo C Zeferino, Alexandra I Zugno, Thais F. Luciano
    Abstract:

    Introduction: Tendinitis affects a substantial number of people in several occupations involving repetitive work or direct trauma. Iontophoresis is a therapeutic alternative used in the treatment of injury during the inflammatory phase. In recent years, gold nanoparticles (GNP) have been studied due to their therapeutic anti-inflammatory capacity and as an alternative to the transport of several proteins. Purpose: This study evaluates the therapeutic effects of iontophoresis using GNPs and diclofenac Diethylammonium on inflammatory parameters in rats challenged with traumatic tendinitis. Methods: Wistar rats were divided in three treatment groups (n = 15): (1) iontophoresis + diclofenac Diethylammonium; (2) iontophoresis + GNP; and (3) iontophoresis + diclofenac Diethylammonium + GNP. External control was formed by challenged tendons without treatment (n = 15). Iontophoresis was administered using 0.3 mA direct current on 1.5 cm² electrodes. Results: The levels of both inflammatory cytokines were significantly higher in untreated challenged rats, when compared with the control (5.398 ± 234 for interleukin 1 beta and 6.411 ± 432 for tumor necrosis factor alpha), which confirms the occurrence of an inflammatory stage in injury (P  0.05). A significant decrease was observed in expression of cytokines interleukin 1 beta in the three treatment groups, in comparison with untreated challenged tendons, although, in the group treated with diclofenac and GNP, results were similar to the control (1.732 ± 239) (P  0.05). Concerning tumor necrosis factor alpha, only the group treated with the association diclofenac and GNPs presented decreased levels, compared with the control (3.221 ± 369) (P  0.05). Conclusion: The results show the efficacy of drug administration using direct current to treat tendinitis in an animal model, and the potential anti-inflammatory, carrier, and enhancing effects

Shigeyoshi Miyagishi - One of the best experts on this subject based on the ideXlab platform.

  • Solubilization of octafluoronaphthalene by mixed micelles of fluorocarbon and hydrocarbon surfactants in aqueous solutions
    Journal of the American Oil Chemists’ Society, 1996
    Co-Authors: Tsuyoshi Asakawa, Junichiro Ikehara, Shigeyoshi Miyagishi
    Abstract:

    Solubilization of octafluoronaphthalene (OFN) by fluorocarbon and hydrocarbon surfactants in aqueous solutions has been examined to investigate the effects of mixing surfactants and added salt. Diethylammonium perfluoronanoate (DEAPFN) micelles have the most solubilization power toward OFN. The difference in micellar solubilization power will be caused by the hydrophobicity of ionic groups and micellar size. Large positive synergistic effects on solubilization behavior were observed in the DEAPFN-Diethylammonium tetradecyl sulfate mixed micellar systems. Solubilization of OFN depended on the concentrations of added salt and the aggregation number, that is, the micellar size.

  • critical demicellization concentration of Diethylammonium perfluorononanoate and Diethylammonium tetradecyl sulfate mixture in aqueous solution
    Bulletin of the Chemical Society of Japan, 1995
    Co-Authors: Tsuyoshi Asakawa, Tsugunori Shiraishi, Shinichi Sunazaki, Shigeyoshi Miyagishi
    Abstract:

    The micellar pseudophase diagram of Diethylammonium perfluorononanoate (DEAPFN) and Diethylammonium tetradecyl sulfate (DEATS) was determined by both conductivity and fluorescence probe methods. The conductivity measurements gave unusually low dissociation degrees of counter ion for DEAPFN-rich regions in contrast to those for DEATS-rich region. The micelles in a DEAPFN-rich region have high microviscosities, suggesting a micellar growth. The existence of the second cmc indicated the presence of two types of mixed micelles, but the mutual solubility of fluorocarbon and hydrocarbon surfactants in micellar pseudophase showed significant differences between DEAPFN–DEATS and LiPFN–LiTS systems. Third inflection points on both conductivity and fluorescence intensity curves were observed for DEAPFN–DEATS system. This suggests the presence of a critical demicellization concentration (CDC).

Marcelo B Dohnert - One of the best experts on this subject based on the ideXlab platform.

  • inflammatory cytokines content in achilles tendinopathy after phonophoresis treatment combined with gold nanoparticles and diclophenac Diethylammonium in rats
    Inflammation, 2015
    Co-Authors: Marcelo B Dohnert, Gabriela K Ferreira, Paulo Cesar Lock Silveira, Elton Torres Zanoni, Luciana H Dohnert, Claudio T De Souza, Marcos Marques Da Silva Paula
    Abstract:

    Tendinitis is a painful condition that occurs in tendons in response to repetitive use or direct trauma. The therapeutic approaches commonly employed to modulate inflammation have not achieved complete success in chronic cases of tendinitis. In this scenario, considering the anti-inflammatory properties of pulsed therapeutic ultrasound and gold nanoparticles (GNPs), this study assesses the possible therapeutic effects of phonophoresis in association with diclophenac Diethylammonium and GNPs by measuring the inflammatory parameters interleukin 1β and tumor necrosis factor alpha in acute tendinous injury. Wistar rats were randomly divided into three groups and were treated with phonophoresis and diclophenac Diethylammonium, GNP gel, and a combination thereof. A significant decrease in interleukin 1β and tumor necrosis factor alpha occurred in tendons treated with phonophoresis + diclophenac + GNPs. The content of both cytokines were similar after combined treatment with phonophoresis + diclophenac + GNPs. Apart from the anti-inflammatory effect, GNPs transported and enhanced drug action when used with phonophoresis.

  • Gold nanoparticles and diclofenac Diethylammonium administered by iontophoresis reduce inflammatory cytokines expression in Achilles tendinitis
    International journal of nanomedicine, 2012
    Co-Authors: Marcelo B Dohnert, Luciana H Dohnert, Claudio T De Souza, Marcos Marques Da Silva Paula, Mirelli Venâncio, Jonathann Corrêa Possato, Rodrigo C Zeferino, Alexandra I Zugno, Thais F. Luciano
    Abstract:

    Introduction: Tendinitis affects a substantial number of people in several occupations involving repetitive work or direct trauma. Iontophoresis is a therapeutic alternative used in the treatment of injury during the inflammatory phase. In recent years, gold nanoparticles (GNP) have been studied due to their therapeutic anti-inflammatory capacity and as an alternative to the transport of several proteins. Purpose: This study evaluates the therapeutic effects of iontophoresis using GNPs and diclofenac Diethylammonium on inflammatory parameters in rats challenged with traumatic tendinitis. Methods: Wistar rats were divided in three treatment groups (n = 15): (1) iontophoresis + diclofenac Diethylammonium; (2) iontophoresis + GNP; and (3) iontophoresis + diclofenac Diethylammonium + GNP. External control was formed by challenged tendons without treatment (n = 15). Iontophoresis was administered using 0.3 mA direct current on 1.5 cm² electrodes. Results: The levels of both inflammatory cytokines were significantly higher in untreated challenged rats, when compared with the control (5.398 ± 234 for interleukin 1 beta and 6.411 ± 432 for tumor necrosis factor alpha), which confirms the occurrence of an inflammatory stage in injury (P  0.05). A significant decrease was observed in expression of cytokines interleukin 1 beta in the three treatment groups, in comparison with untreated challenged tendons, although, in the group treated with diclofenac and GNP, results were similar to the control (1.732 ± 239) (P  0.05). Concerning tumor necrosis factor alpha, only the group treated with the association diclofenac and GNPs presented decreased levels, compared with the control (3.221 ± 369) (P  0.05). Conclusion: The results show the efficacy of drug administration using direct current to treat tendinitis in an animal model, and the potential anti-inflammatory, carrier, and enhancing effects