scholarly journals Some Properties of Polyoxyethylene Dodecyl Ether over a Wide Range of Polyoxyethylene Chain-lengths

1964 ◽  
Vol 37 (12) ◽  
pp. 1837-1841 ◽  
Author(s):  
Fumikatsu Tokiwa
Keyword(s):  
Polyoxyethylene Chain ◽  
Wide Range ◽  
Chain Lengths ◽  
Dodecyl Ether

Controlling the size of Pt nanoparticles with a cationic surfactant, CnTABr

CrystEngComm ◽  
2018 ◽  
Vol 20 (14) ◽  
pp. 2010-2015 ◽  
Author(s):  
Jongsu Seo ◽  
Siwon Lee ◽  
Bonjae Koo ◽  
WooChul Jung
Keyword(s):  
Cationic Surfactant ◽  
Pt Nanoparticles ◽  
Particle Growth ◽  
Colloidal Synthesis ◽  
Chemical Affinity ◽  
Organic Complex ◽  
Wide Range ◽  
Chain Lengths

We report how the size of Pt nanoparticles varies by using a wide range of chain lengths and concentrations of CnTABr, a cationic surfactant, in aqueous-based colloidal synthesis and confirm that the chemical affinity between the organic complex formed in the solution and the aggregate of the surfactant is an important factor for Pt particle growth.

Aqueous foam stabilized by polyoxyethylene dodecyl ether

2009 ◽  
Vol 63 (5) ◽  
Author(s):  
Xi-An Li ◽  
Jian-Bing Peng ◽  
Yong-Li Yan
Keyword(s):  
Aqueous Solutions ◽  
Nonionic Surfactant ◽  
Liquid Crystalline ◽  
Foaming Properties ◽  
Crystalline Phases ◽  
Aqueous Foam ◽  
Liquid Crystalline Phases ◽  
Aqueous Foams ◽  
Chain Lengths ◽  
Dodecyl Ether

AbstractFoaming properties of aqueous solutions of the nonionic surfactant polyoxyethylene dodecyl ether (C12EOn) were studied at 298 K. Four different EO chain lengths, namely C12EO3, C12EO5, C12EO7, and C12EO9, were considered. The foams obtained from C12EO3 or C12EO5 were extraordinary stable retaining a constant volume for more than 20 h. The presence of lamellar liquid crystalline phases was mainly responsible for the super-stable aqueous foams.

Intestinal absorption of 25-hydroxyvitamin D3 in unanesthetized rat.

1979 ◽  
Vol 236 (4) ◽  
pp. E441 ◽  
Author(s):  
D Hollander ◽  
E Rim ◽  
D Morgan
Keyword(s):  
Fatty Acids ◽  
Bile Acid ◽  
Acid Concentration ◽  
Diffusion Mechanism ◽  
Water Layer ◽  
Bile Acid Concentration ◽  
Unstirred Water Layer ◽  
Wide Range ◽  
Bile Drainage ◽  
Chain Lengths

We investigated the mechanism and characteristics of 25-hydroxyvitamin D3 (25-OH-D3) absorption in the unanesthetized rat by using a single-pass intestinal perfusion technique. The rate of 25-OH-D3 absorption remained linear for a wide range of concentrations (2-900 nM). Absorption rate of 25-OH-D3 increased as the pH, the bile acid concentration, and thickness of the unstirred water layer were decreased. Absorption did not change after the additions of fatty acids of varied chain lengths and degrees of saturation. In rats with lymph and bile fistulas, 18.5% and 16.3% of the infused radio-activity appeared in the lymph and bile drainage, respectively. These experiments indicate that 25-OH-D3 is absorbed by a passive diffusion mechanism that is influenced by the intestinal pH, bile acid concentration, and thickness of the unstirred water layer, but not by the presence of fatty acids. Approximately equal fractions of the infused hydroxylated vitamin are recovered from the lymphatic and biliary fluids.

scholarly journals Antimicrobial Evaluation of N-Alkyl Betaines and N-Alkyl-N,N-Dimethylamine Oxides with Variations in Chain Length

2000 ◽  
Vol 44 (9) ◽  
pp. 2514-2517 ◽  
Author(s):  
Christine R. Birnie ◽  
Daniel Malamud ◽  
Roger L. Schnaare
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activity ◽  
Chain Length ◽  
Amine Oxide ◽  
Molar Ratio ◽  
Microdilution Method ◽  
Wide Range ◽  
Broth Microdilution Method ◽  
Antimicrobial Evaluation ◽  
Chain Lengths

ABSTRACT Alkyl betaines and alkyl dimethylamine oxides have been shown to have pronounced antimicrobial activity when used individually or in combination. Although several studies have been conducted with these compounds in combinations, only equimolar concentrations of the C12/C12 and C16/C14chain lengths for the betaine and the amine oxide, respectively, have been investigated. This study investigates the antimicrobial activity of a wide range of chain lengths (C8 to C18) for both the betaine and amine oxide and attempts to correlate their micelle-forming capabilities with their biological activity. A broth microdilution method was used to determine the MICs of these compounds singly and in various molar ratio combinations. Activity against bothStaphylococcus aureus and Escherichia coli was investigated. Antimicrobial activity was found to increase with increasing chain length for both homologous series up to a point, exhibiting a cutoff effect at chain lengths of approximately 16 for betaine and 14 for amine oxide. Additionally, the C18 oleyl derivative of both compounds exhibited activity in the same range as the peak alkyl compounds. Critical micelle concentrations were correlated with MICs, inferring that micellar activity may contribute to the cutoff effect in biological activity.

Effects of Temperature on the Oxidation of Fatty Acids, Acyl Carnitines, and Ketone Bodies by Mitochondria Isolated from the Liver of the Lake Charr, Salvelinus namaycush

1989 ◽  
Vol 46 (6) ◽  
pp. 950-954 ◽  
Author(s):  
J S. Ballantyne ◽  
D. Flannigan ◽  
T. B. White
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Low Temperatures ◽  
Acyl Chain ◽  
Salvelinus Namaycush ◽  
Acid Oxidation ◽  
Wide Range ◽  
Chain Lengths ◽  
Lake Charr

Mitochondria isolated from the liver of the Lake Charr Salvelinus namaycush oxidize a wide range of acyl chain lengths of fatty acids and acyl carnitines at 1, 10, and 20 °C. For most carbon chain lengths the relative importance of carnitine-dependent fatty acid oxidation increases with increasing temperature due to greater thermal enhancement of carnitine-dependent oxidation. At low temperatures the rate of carnitine-independent fatty acid oxidation rivals that of carnitine-dependent oxidation. Therefore, acute temperature shifts during excursions above the thermocline would have important effects on the oxidation of dietary and depot lipids. Temperature does not substantially affect the chain length preference for fatty acid oxidation either in the presence or absence of carnitine, suggesting acclimation-induced changes in substrate specificity of fatty acid oxidation may not be necessary. The importance of β-hydroxybutyrate as an oxidative substrate increases at low temperatures relative to other substrates while acetoacetate oxidation is greater than that of β-hydroxybutyrate at 10 and 20 °C. Altered ketone body metabolism may play a role in regulating cholesterol levels to alter membrane fluidity.

scholarly journals Assessing the use of ellipsoidal microparticles for determining lipid membrane viscosity

2021 ◽  
Author(s):  
Philip E. Jahl ◽  
Raghuveer Parthasarathy
Keyword(s):  
Lipid Membranes ◽  
Lipid Membrane ◽  
Translational Diffusion ◽  
Lipid Domains ◽  
Giant Vesicles ◽  
Membrane Viscosity ◽  
Cellular Processes ◽  
Wide Range ◽  
Chain Lengths ◽  
Good Agreement

The viscosity of lipid membranes sets the timescales of membrane-associated flows and therefore influences the dynamics of a wide range of cellular processes. Techniques to measure membrane viscosity remain sparse, however, and reported measurements to date, even of similar systems, give viscosity values that span orders of magnitude. To address this, we improve a method based on measuring both the rotational and translational diffusion of membrane-anchored microparticles and apply this approach and one based on tracking the motion of phase-separated lipid domains to the same system of phase-separated giant vesicles. We find good agreement between the two methods, with inferred viscosities within a factor of two of each other. Our technique uses ellipsoidal microparticles, and we show that the extraction of physically meaningful viscosity values from their motion requires consideration of their anisotropic shape. The validation of our method on phase-separated membranes makes possible its application to other systems, which we demonstrate by measuring the viscosity of bilayers composed of lipids with different chain lengths ranging from 14 to 20 carbon atoms, revealing a very weak dependence of two-dimensional viscosity on lipid size. The experimental and analysis methods described here should be generally applicable to a variety of membrane systems, both reconstituted and cellular.

scholarly journals Charge Density and Hydrophobicity-Dominated Regimes in the Phase Behavior of Complex Coacervates

2021 ◽  
Author(s):  
Jun Huang ◽  
Jennifer Laaser
Keyword(s):  
Charge Density ◽  
Phase Behavior ◽  
Complex Salt ◽  
Side Chain ◽  
Charge Densities ◽  
Wide Range ◽  
Optical Turbidity ◽  
Chain Lengths ◽  
Coacervate Phase

<div>The role of hydrophobicity, and particularly nonionic hydrophobic comonomers, on the phase behavior of polyelectrolyte complex coacervates is not well-understood. Here, we address this problem by synthesizing a library of polymers with a wide range of charge densities and nonionic hydrophobic side chain lengths, and characterizing their phase behavior by optical turbidity. The polymers were prepared by post-polymerization modification of poly(N-acryloxy succinimide), targeting charge densities between 40 and 100% and nonionic aliphatic sidechains with lengths from 0 to 12 carbons long. Turbidity measurements on pairs of polycations and polyanions with matched charge densities and nonionic sidechain lengths revealed a complex salt response with distinct charge density-dominated and hydrophobicity-dominated regimes. The polymer solubilities were not directly correlated with the phase behavior of the coacervates, indicating the difficulty of understanding the coacervate phase behavior in terms of the polymer-water interaction parameter. This result suggests that there is significant room for further work to understand the mechanisms by which specific molecular-scale interactions moderate the phase behavior of complex coacervates.</div>

scholarly journals Enzyme–Catalysed Synthesis of Palm-Based Wax Esters-A Kinetic Study

2012 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Erin Ryantin Gunawan ◽  
Mahiran Basri ◽  
Dedy Suhendra
Keyword(s):  
Palm Oil ◽  
Oleyl Alcohol ◽  
Wax Esters ◽  
Alcoholysis Reaction ◽  
Ping Pong ◽  
Wide Range ◽  
Chain Lengths ◽  
Menten Constant ◽  
Long Chain ◽  
Mechanism Of The Reaction

Wax esters are long chain esters that are derived from fatty acids and alcohols with chain lengths of 12 carbons or more. Wax esters havea wide range of application in industrial especially in cosmetics. The present work focuses on the synthesis of wax esters by alcoholysisreaction from palm oil and oleyl alcohol in hexane by lipase from Rhizomucor meihei (Lipozyme IM). Effect of various concentrations ofpalm oil and oleyl alcohol were studied to deduce the kinetics and mechanism of the reaction. The alcoholysis reaction followed Michaelis-Menten kinetics. The reaction follows a Ping-pong Bi-Bi mechanism. The maximum rate was estimated to be 6 x 10 -3 mmol/h. mg catalystand the Michaelis-Menten constant for palm oil and oleyl alcohol were 4.145 M and 6.120 M, respectively.

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