摘要:

The influence that 1,3-butyleneglycol incorporated as polar cosolvent in the aqueous phase determine on the O/ W micromulsion region of the classical system water/ sodium dodecyl sulfate/ pentanol/ heptane, has been studied. Phase diagrams corresponding to aqueous phases made of water/ butyleneglycol in ratios 907sol; 10 and 75/ 25 are compared with the typical system with water.The resulting increase on the OAV microemulsion region for the systems including the glycol, provides a security margin to prepare such compositions with respect to the narrow channel of solubility described for the conventional system. Although the presence of butyleneglycol lead to a shift in the optimal ratio between the aqueous phase and SDS from the 85/ 15 described for the typical system to higher proportions in surfactant, the simplicity of preparation of such O/W microemulsions could compensate the higher amount of SDS required

ISSN:0193-2691    

DOI:10.1080/01932699908943837

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The domains of homogeneity for the systems containing styrene - alcohol (methanol, isopropanol, t-butanol) - water are investigated. These ones represent the reaction medium of dispersion polymerization The domains of homogeneity increase with increasing the hydrocarbon chain of the cosurfactant and in the presence of surfactants. Conductometric and refractometric studies have established that the homogeneous systems obtained in the presence of monomaleate of nonylphenol ethoxylated with 25 moles ethylene oxide, in a concentration of 10% based on the above-mentioned mixture, are microemulsions with oil-in-water (o/ w) bicontinuous or water-in-oil (w/ o) structure. In the presence of 10% bismethacrylate of PEG 1500 or 5% bismethacrylate of PEG 1500 and 5% acrylic acid, based on styrene, the domains of homogeneity are smaller, but the character of microemulsion is preserved. The latexes prepared by polymerizing styrene dispersed in microemulsions display larger particle diameter in case of isopropanol, owing to partial swelling.

ISSN:0193-2691    

DOI:10.1080/01932699908943838

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699908943839

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The strength of attachment of adsorbed bovine β-lactoglobulin (βlg) and acetylated β-lactoglobulin (Ac-βlg) has been studied by comparing the elution profiles of the adsorbed proteins. βlg binds very loosely to alumina at pH 4.2 and both βlg and Ac-βlg bind very tightly to alumina at pH 5.1 where the proteins showed highest adsorption at alumina/ water interface [ Bhaduri, A & Das, K. P., J. Disp. Sci. Technol., 15, 165-188 (1994)]. Adsorbed protein can only be eluted out if the pH of the elution buffer is raised to 7.6. βlg elutes as a single peak whereas Ac-βlg as two peaks indicating the later is adsorbed to alumina with different affinities. Elution profile of adsorbed βlg at pH 6.3 shows that adsorbed βlg population consists of partly folded elutable fraction and partly unfolded resistant one. The interaction of first layer of protein with the silica surface at pH 5.1 is primarily hydrophobic for βlg and electrostatic for Ac-βlg.

ISSN:0193-2691    

DOI:10.1080/01932699908943840

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Several representative systems of surfactant + alkaline combination flooding are chosen to study in this paper, these systems are characterized in two points: The first: oil is miscible with water only by reversing them five to ten times, this miscible process is close to spontaneous. Interfacial tension between oil and aqueous is ultra-low. The second: this type of systems is high dispersion and can be stabilized in a period of time. These systems are observed by inicroscopy, polarizing microscopy, microcalorimetry, laser particles analysis instrument and interfacial tension meter, it is found that small particles are main constituent and special liquid crystals distributed on the surface of small particles exist. Small particles and special liquid crystals are responsible for producing ultra-low interfacial tension. The middle phase microemulsion of sodium dodecylsulfate is studied. By comparing difference and similarity between middle phase microemulsion and miscible system, mechanisms of forming low interfacial tension in miscible system and middle phase microemulsion are discussed initially.

ISSN:0193-2691    

DOI:10.1080/01932699908943841

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Molecular chaperones prevent protein aggregation. Understanding of their mechanism of actions remains obscured by the complexity of their three dimensional structure. Surfactants are much simpler molecules and can also inhibit protein aggregation. In the present work, prevention of aggregation by ionic and non-ionic surfactants during thermal and non-thermal unfolding and refolding of a number of proteins are studied. Attempts have been made to compare the dose dependence of surfactants with that of molecular chaperone a-crystallin in preventing various protein aggregations. Conformational features of proteins whose aggregation have been prevented by surfactants and a-crystallin are compared with each other. It has been found that in terms of conformation of the substrate protein, chaperones restrict the bound protein in a conformation not far from that of the native protein, whereas ionic surfactants may lead to considerably different substrate protein conformation. Non-ionic surfactants, though slow in solubilising protein aggregates, do not cause great changes in protein conformation.

ISSN:0193-2691    

DOI:10.1080/01932699908943842

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Adsorption of Methylene Blue ( MB) on Na-, Fe- and Al-montmorillonite suspensions at 298.15 K were studied. The effect of different exchangeable cation on the adsorption amount of MB was determined. The results show that methylene blue cations( MB+) replace Na* more easily than they do Fe3+and Al3 +The adsorption isotherms on the three montraorillonites were all of Langmuir type, except that the isouHerm of MB on Na-montmorillonite presents nonmonotonic curve at low surface coverage. The specific surface areas in suspension were calculated by( MB3 +)method, and Na−is more effective to determine the specific surface area by MB method in suspension than Fe3 +and A3 +The discrepancy of the specific surface area measured by MB and BET method was discussed.

ISSN:0193-2691    

DOI:10.1080/01932699908943843

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Liposomes are microscopic vesicles composed of phospholipid bilayers surrounding discrete aqueous compartment. Eventhough phospholipid bilayers are formed spontaneously in water, their conventional preparation methods involve either organic solvents or detergent molecules. Organic solvents may create a serious safety problem during liposome manufacturing especially on a large scale and can cause denaturation of proteins and affect the membrane properties. Liposomes are very promising carriers for protein drugs which have aroused great interests in the field of pharmaceutics in these recent years.

ISSN:0193-2691    

DOI:10.1080/01932699908943844

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The diffusion coefficient of the micelle, the first CMC and the second CMC of Triton X-100 are determined by cyclic voltammetry without any probe. The first CMC and the second CMC of Triton X-100 are 3.1x lO−1and 1.3× 10−1respectively. The viscosity of the micelle solution, the micellar aggregation number and the micellar size increase but the diffusion coefficient decreases with Triton X-100 concentration increasing. The mechanism of the electrochemical reaction of Triton X-100 at platinum electrode is deduced by measurements of conductivity, pH and cyclic voltammetry.

ISSN:0193-2691    

DOI:10.1080/01932699908943845

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The phase diagram of the dodecyl dimethyl ammonium hydroxyl propyl sulfonate( DDAHPS)/ l-pentanol(C5HnOH)/ water ternary system has been established. It contains two isotropic monophase regions(Li and L:) and a liquid crystalline region( L.C.). The isotropic phase regions have been investigated by means of Raman spectroscopy and conductivity.

ISSN:0193-2691    

DOI:10.1080/01932699908943846

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor