Presence Of Surface Active Agents Research Articles

Analytical application of the cobalt(II) catalytic pre-wave in the presence of thiamine in its disulphide form.

The cobalt catalytic pre-wave in the presence of thiamine in its disulphide form, and in a borate medium, was studied as a function of the thiamine (disulphide form) and cobalt(II) concentrations and of the pH of the solution. The effects of temperature, the addition of neutral salts and the presence of surface-active agents on the pre-wave are described. The effect of thiamine (disulphide form) is shown on the electrocapillary curves. The electrode process involves the formation of complexes between cobalt(II) and thiamine, in its thiolic form, adsorbed on the dropping-mercury electrode, and the electrochemical decomposition of these complexes with liberation of the catalytic ligand. The analytical application of this pre-wave was studied.

Aerobic bacterial counts on human skin after bathing.

SUMMARY Liquid-elution counts in a non-ionic surfactant and imprint replicate counts with velvet pads were used to investigate the changes in total bacterial and colony counts on normal skin surfaces after bathing with water, soap, or detergent. The experiments revealed that the total bacterial count on several skin sites was reduced soon after washing, returning in 24 hr to the pre-wash numbers. In contrast, the colonial count from the same sites increased considerably after washing, again returning to the pre-wash count. An explanation is offered that both kinds of counts were sampled from extremely large aggregates of bacteria on the skin surface, and that these aggregates could be segregated into very much smaller viable units, each still capable of originating individual colonies by either counting method. It is suggested that the extent of separation depended on the mechanical processes of washing, the presence of surface-active agents in the washing water, and the use of a non-ionic surfactant in the sampling and subsequent counting procedure.

The Polymerization of Vinyl Monomers in the Presence of Surface Active Agents. I. The Polymerization of Methyl Methacrylate

Abstract Methyl methacrylate polymerized in the presence of a surface active agent in an aqueous system without any ordinary initiators. Anionic surface active agents, such as sodium tetrapropylenebenzenesulfonate and sodium 2-dodecylbenzenesulfonate, markedly effected the polymerization of methyl methacrylate in the presence of water. The polymerization was inhibited by adding hydroquinone to the reaction system and was also affected adversely by oxygen. Water as a reaction medium was found to be indispensable. The polymerization in organic solvents afforded hardly any polymeric products.

The stability of hydrophobic sols in the presence of surface active agents

The stability of hydrophobic sols in the presence of surface active agents

Unsymmetrical drainage beneath a rigid sphere approaching a deformable liquid-liquid interface

The approach of rigid spheres of uniform and non-uniform density to deformable liquid-liquid interfaces has been studied photographically. Symmetrical drainage occurs beneath spheres of uniform density so that the profiles of the draining film are symmetrical about the vertical axis of the sphere. However unsymmetrical drainage occurs beneath spheres of non-uniform density due to rotation of the sphere so that the profiles of the draining film are unsymmetrical about the vertical axis of the sphere. The presence of surface active agent in the liquid-liquid interface reduces the rate of rotation so making the drainage more symmetrical.

The stability of hydrophobic sols in the presence of surface active agents

The zeta potential measurements were carried out in the presence of surface active agents under the conditions as described in Part I. The cell used in these measurements was similar to that described byMattson. The shape of zeta-potential-log10 concentration curves was found to be of S shaped. This behaviour was ascribed due to the strong adsorption of surface active agents at the solid-liquid interface. On the basis of these results changes in the charge density of the Gouy layer i.e. were calculated in the vicinity of the zero point of charge; these in turn led to computation of electro-chemical energy of adsorption. The magnitude of this energy varied from 5.730–6.160 cal per mole for different surface active agent used. An attempt has been made to give a physical picture of the mode of adsorption of these compounds on the surface of thorium dioxide particles.

Some Basic Concepts Regarding the Separation of Oily Water Mixtures

The various factors that determine the stability and separation rate of oil from oily water mixtures are reviewed. The effect of droplet size, viscosity and unique interfacial properties promoted by the presence of surface-active agents are considered. The appropriate means to handle the separation/removal of oil from waste water effluents, as influenced by these factors, will be discussed. Wherever possible, first principles are applied; conversely, other areas are indicated where the nature of the problem dictates the reliance on empirical results and test data. Specific problems, properties and equipment are used throughout the presentation to illustrate the various concepts.

The effect of surface active agents on the stability characteristics of falling liquid films

The effect of the presence of surface active agents on the stability characteristics of falling liquid films is considered. Using an asymptotic analysis based on the assumption of a large surface elasticity parameter, it is shown that: (1) the bifurcation Reynolds number which is obtained via a small wave number perturbation solution is indeed the critical Reynolds number for the system, and (2) that the presence of surfactants results in a large decrease in the growth rate and a large increase in the wave length of the most rapidly amplified disturbance.

The effect of surface active agents on convection cells induced by surface tension

Numerous experiments have indicated that surface active agents exert a profound stabilizing effect on convection induced by surface tension. The stabilization is predicted theoretically here by extending P earson's stability analysis of surface tension induced convection to account for the presence of surface active agents.

Crystal Growth of Sodium Acid Urate

Symptoms of gouty arthritis are caused by the deposition of needle crystals of sodium acid urate in intrasynovial fluids. Since only the needle habit causes the inflammatory reaction, any compound that retards needle axis growth may be a potential drug for this disease. This study was designed to test a number of compounds for their inhibitory effect on the needle axis growth rate of sodium acid urate crystals. Instrumentation for single crystal alignment and crystal growth measurement is described. Growth data are presented as a function of the degree of supersaturation. The inhibitory effect of benzalkonium chloride was measured. Photomicrographs of crystals, grown in the presence of surface-active agents, show the habit changes which can be obtained. Symptoms of gouty arthritis are caused by the deposition of needle crystals of sodium acid urate in intrasynovial fluids. Since only the needle habit causes the inflammatory reaction, any compound that retards needle axis growth may be a potential drug for this disease. This study was designed to test a number of compounds for their inhibitory effect on the needle axis growth rate of sodium acid urate crystals. Instrumentation for single crystal alignment and crystal growth measurement is described. Growth data are presented as a function of the degree of supersaturation. The inhibitory effect of benzalkonium chloride was measured. Photomicrographs of crystals, grown in the presence of surface-active agents, show the habit changes which can be obtained.

Availability of Drugs in the Presence of Surface-Active Agents I: Critical Micelle Concentrations of Some Oxyethylene Oxypropylene Polymers

The critical micelle concentrations (CMC's) of the three nonionic surface-active agents—oxyethylene oxypropylene polymers known as Pluronic L 62, Pluronic L 64, and Pluronic F68—were determined by the surface-tension method and two spectral absorption methods—one employing iodine and the other benzopurpurine 4B. The CMC's for these agents were found to be 2.40 Gm./dl., 2.20 Gm./dl., and 0.1 Gm./dl., respectively.

The stability of hydrophobic sols in the presence of surface-active agents. Part 2.—The stability of silver iodide sols in the presence of cationic surface-active agents

The stability of hydrophobic sols in the presence of surface-active agents. Part 2.—The stability of silver iodide sols in the presence of cationic surface-active agents

The stability of hydrophobic sols in the presence of surface-active agents. Part 3.—An examination by microelectrophoresis of the behaviour of silver iodide sols in the presence of cationic surface-active agents

The first page of this article is displayed as the abstract.

The stability of hydrophobic sols in the presence of surface-active agents. Part 1.—Theoretical treatment

The first page of this article is displayed as the abstract.

The Kinetics of Rectal Absorption II. : The Absorption of Anions

The rectal absorption rates of sodium iodide and the sodium salt of 2,4,6-triiodophenol in suppository bases at various pH values and in the presence of surface-active agents and polyethylene glycol additives were determined by continuous external detection at the site of insertion. The rate of sodium iodide absorption is accelerated in the presence of surfactants and appears to be proportional to the surface tension lowering and the peptizing action of their surface active components. The rate of absorption of the phenolate is retarded by the presence of surfactants. Hydrolysis and subsequent solubilization of the free phenol is postulated to explain this effect.

The Electrokinetic Behavior of Inorganic Substances in the Presence of Surface Active Agents

The Electrokinetic Behavior of Inorganic Substances in the Presence of Surface Active Agents

(7)界面活性剤の存在における塩酸による酢酸ブチルの加水分解反応,その他の関連反応

(7)界面活性剤の存在における塩酸による酢酸ブチルの加水分解反応,その他の関連反応

A Suspension Bath for the Study of Isolated Tissues in the Presence of Surface Active Agents

A Suspension Bath for the Study of Isolated Tissues in the Presence of Surface Active Agents

The Effects of Surface-Active Agents on Bacitracin Activity in Vitro*

The antibacterial action of bacitracin is significantly and selectively affected by the presence of surface-active agents as determined by the paper-disk assay, using Micrococcus flavus as the test organism. Potency is enhanced by cationic and nonionic compounds and is decreased by anionic. This effect with benzethonium chloride can be shown in the case of other organisms, namely, Staphylococcus aureus, Streptococcus pyogenes, and Neisseria catarrhalis. Because of the potent antiseptic action of the quaternary ammonium agents, it is suggested that combinations of these with bacitracin may be well suited to the local treatment of infections where greater penetration of the tissue is desired.