Search results for "Surfactant"

Goldschmidt Abstracts 2010 – J

2010

Glycolipid Biosurfactant Production from Waste Cooking Oils by Yeast: Review of Substrates, Producers and Products

2021

Biosurfactants are a microbially synthesized alternative to synthetic surfactants, one of the most important bulk chemicals. Some yeast species are proven to be exceptional biosurfactant producers, while others are emerging producers. A set of factors affects the type, amount, and properties of the biosurfactant produced, as well as the environmental impact and costs of biosurfactant’s production. Exploring waste cooking oil as a substrate for biosurfactants’ production serves as an effective cost-cutting strategy, yet it has some limitations. This review explores the existing knowledge on utilizing waste cooking oil as a feedstock to produce glycolipid biosurfactants by yeast. The review f…

Comparative assessment of a foam-based method for ISCO of coal tar contaminated unsaturated soils

2019

Abstract In situ delivery of liquid reagents in vadose zone is limited by gravity and soil anisotropy. A new foam-based delivery method of persulfate (PS) solutions in unsaturated soils was previously shown to overcome these limitations. The goal of this paper is to demonstrate the efficiency of this method regarding contaminant removal. Hence, the comparative oxidation of 200 mg.kg−1 coal tar artificially contaminated soils with thermally activated PS was carried out after PS-delivery using foam, surfactant solution and pure water. The foam-based method was compared in unfavorable conditions to the reference methods. Especially, in the latter, soil and oxidant solutions were thoroughly mix…

Physicochemical and Preclinical Evaluation of Spermine-Derived Surfactant Liposomes for in Vitro and in Vivo siRNA-Delivery to Liver Macrophages

2016

Herein we report on a liposomal system for siRNA delivery consisting of cholesterol (Chol), distearoylphosphatidylcholine (DSPC), and surfactant TF (1-hydroxy-50-amino-3,4,7,10,13,16,19,22-octaoxa-37,41,45-triaza-pentacontane), a novel spermine derivative (HO-EG8-C12-spermine) which has shown improved siRNA delivery to cells in vitro and in vivo. Predominantly single-walled liposomes with reproducible sizes and moderately broad size distributions were generated with an automated extrusion device. The liposomes remained stable when prepared in the presence of siRNA at N/P ratios of 17-34. However, when mixed with human serum in equal volumes, larger aggregates in the size range of several hu…

Role of pulmonary surfactant protein Sp-C dimerization on membrane fragmentation: An emergent mechanism involved in lung defense and homeostasis.

2020

Surfactant protein C (SP-C) is a protein present in the pulmonary surfactant system that is involved in the biophysical properties of this lipoprotein complex, but it also has a role in lung defense and homeostasis. In this article, we propose that the link between both functions could rely on the ability of SP-C to induce fragmentation of phospholipid membranes and generate small vesicles that serve as support to present different ligands to cells in the lungs. Our results using bimolecular fluorescence complementation and tunable resistive pulse sensing setups suggest that SP-C oligomerization could be the triggering event that causes membrane budding and nanovesiculation. As shown by flu…

Asthmatics with high levels of serum surfactant protein D have more severe disease.

2016

Pulmonary surfactant is a mixture of lipids and surfactant-specific proteins that covers the alveolar surface, as well as the terminal conducting airways, lowering the surface tension at the air–liquid interface during breathing. The involvement of pulmonary surfactant in the pathophysiology of asthma has been suggested. An interesting working hypothesis is that the surface tension of the peripheral airways is altered in asthma, because the inflammatory process affects the structure and function of surfactant, leading to excessive airway narrowing and features of air trapping. We explored whether serum levels of surfactant protein D (SP-D) in asthmatics are related to the severity of the di…

Palmitic Acid: Physiological Role, Metabolism and Nutritional Implications

2017

Palmitic acid (PA) has been for long time negatively depicted for its putative detrimental health effects, shadowing its multiple crucial physiological activities. PA is the most common saturated fatty acid accounting for 20–30% of total fatty acids in the human body and can be provided in the diet or synthesized endogenously via de novo lipogenesis (DNL). PA tissue content seems to be controlled around a well-defined concentration, and changes in its intake do not influence significantly its tissue concentration because the exogenous source is counterbalanced by PA endogenous biosynthesis. Particular physiopathological conditions and nutritional factors may strongly induce DNL, resulting i…

Development of a method to determine axitinib, lapatinib and afatinib in plasma by micellar liquid chromatography and validation by the European Medi…

2017

A method based on micellar liquid chromatography to quantify the tyrosine kinase inhibitors axitinib, lapatinib and afatinib in plasma is reported. The sample pretreatment was a simple 1/5-dilution in a pure micellar solution, filtration and direct injection, without requiring extraction or purification steps. The three drugs were resolved from the matrix in 17 min, using an aqueous solution of 0.07 M sodium dodecyl sulfate – 6.0% 1-pentanol, buffered at pH 7 with 0.01 M phosphate salt as mobile phase, running under isocratic mode at 1 mL/min through a C18 column. The detection was performed by absorbance at 260 nm. An accurate mathematical relationship was established between the retention…

Utilization of impedance spectroscopy to investigate the self-assembly behavior of amphiphiles soluble in supercritical carbon dioxide: Preliminary r…

2007

Abstract A mixture of CO 2 , water, methyl orange (MO) and Dynol 604 surfactant was analyzed at 309 K and 20 MPa simultaneously by impedance and UV–vis spectroscopy. A plot of the static dielectric constant as a function of the surfactant concentration was obtained using a suitable equivalent circuit to elaborate impedance data. Experimental points can be fitted by two different straight lines whose intersection occurs at about 0.13% (w/w) concentration of Dynol. When the surfactant concentration crossed the aforementioned value, a peak was detectable in the UV–vis spectrum at a wavelength range corresponding to the absorption of MO; absorbance of the peak increased with the surfactant conc…

Isocratic and gradient elution in micellar liquid chromatography with Brij-35

2015

Polyoxyethylene(23)lauryl ether (known as Brij-35) is a nonionic surfactant, which has been considered as an alternative to the extensively used in micellar liquid chromatography anionic surfactant sodium lauryl (dodecyl) sulfate, for the analysis of drugs and other types of compounds. Brij-35 is the most suitable nonionic surfactant for micellar liquid chromatography, owing to its commercial availability, low cost, low toxicity, high cloud temperature, and low background absorbance. However, it has had minor use. In this work, we gather and discuss some results obtained in our laboratory with several β-blockers, sulfonamides, and flavonoids, concerning the use of Brij-35 as mobile phase mo…