The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Kazuya Saito - One of the best experts on this subject based on the ideXlab platform.
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effect of cis and trans double bonds on conformational disordering of the Hydrocarbon Chain of lipid unsaturated monoacylglycerols in the lamellar phase of a binary system with water
Journal of Physical Chemistry B, 2011Co-Authors: Yasuhisa Yamamura, Kazuya SaitoAbstract:To clarify the influence of cis and trans double bonds on conformational disordering of unsaturated Hydrocarbon-Chain of lipids in bilayer formed in the binary system with water, calorimetric study was conducted for systems of unsaturated monoacylglycerols; monoolein (MO), monovaccenin (MV), and monoelaidin (ME). Heat capacities of the binary systems were measured by adiabatic calorimetry. The observed entropies of transition (ΔtrsS) from lamellar phase (Lα) to fluid isotropic (FI) phase are very small and depend on lipids: ΔtrsS of MO/water, MV/water, and ME/water were ca. 0.8 J K–1 (mol of lipid) –1, ca. 0.9 J K–1 (mol of lipid) –1, and ca. 0.4 J K–1 (mol of lipid) –1, respectively. These show that the conformational disordering of the Hydrocarbon Chain over gauche and trans conformations is suppresed in Lα phase. Through the comparison of ΔtrsS among the binary systems, the suppresed conformational disordering of Hydrocarbon Chain in the bilayer is discussed.
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effect of cis and trans double bonds on conformational disordering of the Hydrocarbon Chain of lipid unsaturated monoacylglycerols in the lamellar phase of a binary system with water
Journal of Physical Chemistry B, 2011Co-Authors: Yasuhisa Yamamura, Kazuya SaitoAbstract:To clarify the influence of cis and trans double bonds on conformational disordering of unsaturated Hydrocarbon-Chain of lipids in bilayer formed in the binary system with water, calorimetric study was conducted for systems of unsaturated monoacylglycerols; monoolein (MO), monovaccenin (MV), and monoelaidin (ME). Heat capacities of the binary systems were measured by adiabatic calorimetry. The observed entropies of transition (ΔtrsS) from lamellar phase (Lα) to fluid isotropic (FI) phase are very small and depend on lipids: ΔtrsS of MO/water, MV/water, and ME/water were ca. 0.8 J K–1 (mol of lipid) –1, ca. 0.9 J K–1 (mol of lipid) –1, and ca. 0.4 J K–1 (mol of lipid) –1, respectively. These show that the conformational disordering of the Hydrocarbon Chain over gauche and trans conformations is suppresed in Lα phase. Through the comparison of ΔtrsS among the binary systems, the suppresed conformational disordering of Hydrocarbon Chain in the bilayer is discussed.
Santanu Bhattacharya - One of the best experts on this subject based on the ideXlab platform.
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effect of the Hydrocarbon Chain and polymethylene spacer lengths on gene transfection efficacies of gemini lipids based on aromatic backbone
Bioconjugate Chemistry, 2007Co-Authors: Avinash Bajaj, Bishwajit Paul, S S Indi, Paturu Kondaiah, Santanu BhattacharyaAbstract:Design, syntheses, and gene delivery efficacies of fifteen novel gemini (dimeric) and three monomeric cationic lipids anchored on an aromatic backbone have been described. Each new lipid has been used for liposome formation, and optimal formulations were used to determine the structure–activity correlation of the gene transfection efficacies of these lipids in HeLa and HT1080 cells. The results of the present investigation bring out the effect of Hydrocarbon Chain lengths and the length of the spacer between the headgroups on gene transfection efficiencies of the cationic gemini lipids based on aromatic backbone. The lipids bearing n-C14H29 Hydrocarbon Chain lengths have been found to be the best transfecting agents compared to their counterparts with n-C16H33 and n-C12H25 Chains in HeLa cells. On the other hand, in HT1080 cells, the lipids based on n-C12H25 and n-C14H29 Chains were found to be more potent transfecting agents than lipids possessing n-C16H33 Chains. Transmission electron microscopy examina...
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incorporation of oxyethylene units between Hydrocarbon Chain and pseudoglyceryl backbone in cationic lipid potentiates gene transfection efficiency in the presence of serum
FEBS Letters, 2001Co-Authors: Padinjarae Vangasseri Dileep, Santanu Bhattacharya, A AntonyAbstract:Four novel cationic lipids with different numbers of oxyethylene units at the linkage region between the pseudoglyceryl backbone and the Hydrocarbon Chains have been synthesized and used as mixtures with 1,2-dioleoyl- -α-glycero-3-phosphatidyl ethanolamine (DOPE) for liposome-mediated gene transfection. Incorporation of different numbers of oxyethylene (–CH2CH2O–) units between long Hydrocarbon Chain at the C-1 and C-2 positions of the pseudoglyceryl skeleton improved the transfection efficiency considerably compared to the one in which the Chains were connected via simple ether links. A pronounced improvement in the gene transfer efficiency was observed with the unsymmetrical cationic lipid 3 in which the long Hydrocarbon at the C-1 position of the pseudoglyceryl segment is connected via two (–CH2CH2O–) units. Notably, the transfection ability of lipid 3 with DOPE in the presence of serum was significantly greater than LIPOFECTAMINE®. This suggests that introduction of oxyethylene units between long Hydrocarbon Chains at the C-1 and C-2 positions of the pseudoglyceryl skeleton provides a novel strategy to achieve efficient gene transfer, especially in conditions where the presence of serum is critical.
Yasuhisa Yamamura - One of the best experts on this subject based on the ideXlab platform.
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effect of cis and trans double bonds on conformational disordering of the Hydrocarbon Chain of lipid unsaturated monoacylglycerols in the lamellar phase of a binary system with water
Journal of Physical Chemistry B, 2011Co-Authors: Yasuhisa Yamamura, Kazuya SaitoAbstract:To clarify the influence of cis and trans double bonds on conformational disordering of unsaturated Hydrocarbon-Chain of lipids in bilayer formed in the binary system with water, calorimetric study was conducted for systems of unsaturated monoacylglycerols; monoolein (MO), monovaccenin (MV), and monoelaidin (ME). Heat capacities of the binary systems were measured by adiabatic calorimetry. The observed entropies of transition (ΔtrsS) from lamellar phase (Lα) to fluid isotropic (FI) phase are very small and depend on lipids: ΔtrsS of MO/water, MV/water, and ME/water were ca. 0.8 J K–1 (mol of lipid) –1, ca. 0.9 J K–1 (mol of lipid) –1, and ca. 0.4 J K–1 (mol of lipid) –1, respectively. These show that the conformational disordering of the Hydrocarbon Chain over gauche and trans conformations is suppresed in Lα phase. Through the comparison of ΔtrsS among the binary systems, the suppresed conformational disordering of Hydrocarbon Chain in the bilayer is discussed.
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effect of cis and trans double bonds on conformational disordering of the Hydrocarbon Chain of lipid unsaturated monoacylglycerols in the lamellar phase of a binary system with water
Journal of Physical Chemistry B, 2011Co-Authors: Yasuhisa Yamamura, Kazuya SaitoAbstract:To clarify the influence of cis and trans double bonds on conformational disordering of unsaturated Hydrocarbon-Chain of lipids in bilayer formed in the binary system with water, calorimetric study was conducted for systems of unsaturated monoacylglycerols; monoolein (MO), monovaccenin (MV), and monoelaidin (ME). Heat capacities of the binary systems were measured by adiabatic calorimetry. The observed entropies of transition (ΔtrsS) from lamellar phase (Lα) to fluid isotropic (FI) phase are very small and depend on lipids: ΔtrsS of MO/water, MV/water, and ME/water were ca. 0.8 J K–1 (mol of lipid) –1, ca. 0.9 J K–1 (mol of lipid) –1, and ca. 0.4 J K–1 (mol of lipid) –1, respectively. These show that the conformational disordering of the Hydrocarbon Chain over gauche and trans conformations is suppresed in Lα phase. Through the comparison of ΔtrsS among the binary systems, the suppresed conformational disordering of Hydrocarbon Chain in the bilayer is discussed.
Milton J. Rosen - One of the best experts on this subject based on the ideXlab platform.
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Synergism in the spreading of Hydrocarbon-Chain surfactants on polyethylene film-anionic and cationic mixtures by a two-step procedure.
Langmuir : the ACS journal of surfaces and colloids, 2005Co-Authors: Milton J. RosenAbstract:A study has been made of the adsorption, interaction, and spreading of mixtures of anionic and cationic surfactants at the aqueous solution/polyethylene (PE) interface. When a drop of an aqueous solution of an anionic or cationic Hydrocarbon-Chain surfactant is placed on a highly hydrophobic PE film (contact angle of water > 90 °), it spreads to an area very little larger than that of a drop of water of the same volume. If the anionic and cationic Hydrocarbon-Chain surfactant solutions are mixed prior to being applied to PE film, synergism is small, if any, and the reproducibility of the experimental results is poor. However, when the cationic and anionic aqueous solutions are applied on the PE film in a sequential manner, a remarkable synergism in spreading is observed and the results are very reproducible. The area spread by an aqueous solution of the anionic−cationic mixture may be more than 400 times that of aqueous solutions of the same volume and surfactant concentration of the individual surfactant...
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Synergism in the Spreading of Hydrocarbon-Chain Surfactants on Polyethylene FilmAnionic and Cationic Mixtures by a Two-Step Procedure
Langmuir : the ACS journal of surfaces and colloids, 2005Co-Authors: Milton J. RosenAbstract:A study has been made of the adsorption, interaction, and spreading of mixtures of anionic and cationic surfactants at the aqueous solution/polyethylene (PE) interface. When a drop of an aqueous solution of an anionic or cationic Hydrocarbon-Chain surfactant is placed on a highly hydrophobic PE film (contact angle of water > 90 °), it spreads to an area very little larger than that of a drop of water of the same volume. If the anionic and cationic Hydrocarbon-Chain surfactant solutions are mixed prior to being applied to PE film, synergism is small, if any, and the reproducibility of the experimental results is poor. However, when the cationic and anionic aqueous solutions are applied on the PE film in a sequential manner, a remarkable synergism in spreading is observed and the results are very reproducible. The area spread by an aqueous solution of the anionic−cationic mixture may be more than 400 times that of aqueous solutions of the same volume and surfactant concentration of the individual surfactant...
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Surfactant-surfactant molecular interactions in mixed monolayers at a highly hydrophobic solid/aqueous solution interface and their relationship to enhanced spreading on the solid substrate
Langmuir, 2003Co-Authors: Qiong Zhou, Yongfu Wu, Milton J. RosenAbstract:Spreading of mixed aqueous Hydrocarbon-Chain surfactant solutions on the solid polyethylene (PE) surface has been studied. Synergistic effect on the spreading of the mixed surfactant solution on the PE film has been observed, and the obtained spreading is comparable to superspreading normally obtainable from trisiloxane-based surfactants. Some other interfacial phenomena related to surfactant spreading, such as surfactant−surfactant molecular interactions in the mixtures adsorbed at various interfaces, dynamic contact angle change of the mixed surfactant solutions during the process of spreading on the hydrophobic PE substrate, and surfactant adsorption at the solid/liquid and air/liquid interfaces have been investigated. It is suggested that stronger surfactant−surfactant attractive interactions and greater adsorption at the PE powder/aqueous solution interface than at the air/aqueous solution interface account for the observed spreading enhancement in the mixed Hydrocarbon-Chain surfactant systems, whic...
Frédéric Guittard - One of the best experts on this subject based on the ideXlab platform.
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Effect of Hydrocarbon Chain branching in the elaboration of superhydrophobic materials by electrodeposition of conducting polymers
Surface and Coatings Technology, 2014Co-Authors: Mélanie Wolfs, Thierry Darmanin, Frédéric GuittardAbstract:Here, we study for the first time the influence of Hydrocarbon Chain branching on the formation of surface structures and on superhydrophobic properties obtained by electrodeposition of conducting polymers. Two series of 3,4-ethylenedioxythiophene (EDOT) derivatives with branched Hydrocarbon Chains were synthetized and the surface properties were compared with linear Hydrocarbon Chains. We show that Hydrocarbon Chain branching reduces the intrinsic hydrophobicity of the substituent. As a consequence, the branching can lead to smoother films, due to the increase in solubility of the oligomers formed in the first instances of the polymerization, than that obtained with linear Hydrocarbon Chains. Here, highly structured films with non-wetting properties close to superhydrophobic properties are obtained with linear Hydrocarbon Chains from a total number of carbon of 8 while relatively smooth hydrophobic films are obtained with branched Hydrocarbon Chains. This work is extremely important in the control of the surface properties of electrodeposited conducting polymers.
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Effect of Hydrocarbon Chain branching in the elaboration of superhydrophobic materials by electrodeposition of conducting polymers
Surface and Coatings Technology, 2014Co-Authors: Mélanie Wolfs, Thierry Darmanin, Frédéric GuittardAbstract:Abstract Here, we study for the first time the influence of Hydrocarbon Chain branching on the formation of surface structures and on superhydrophobic properties obtained by electrodeposition of conducting polymers. Two series of 3,4-ethylenedioxythiophene (EDOT) derivatives with branched Hydrocarbon Chains were synthetized and the surface properties were compared with linear Hydrocarbon Chains. We show that Hydrocarbon Chain branching reduces the intrinsic hydrophobicity of the substituent. As a consequence, the branching can lead to smoother films, due to the increase in the solubility of the oligomers formed in the first instances of the polymerization, than that obtained with linear Hydrocarbon Chains. Here, highly structured films with non-wetting properties close to superhydrophobic properties are obtained with linear Hydrocarbon Chains from a total number of carbon of 8 while relatively smooth hydrophobic films are obtained with branched Hydrocarbon Chains. This work is extremely important in the control of the surface properties of electrodeposited conducting polymers.