Sodium N-lauroyl Research Articles

MECHANISM OF INHIBITION OF GALVANIC CORROSION BETWEEN CARBON STEEL AND STAINLESS STEEL BY SODIUM N-LAUROYL SARCOSINATE AND ZINC SULFATE

Inhibition effect of sodium [Formula: see text]-lauroyl sarcosinate and zinc sulfate on the galvanic corrosion between carbon steel and stainless steel in 1% NaCl solution was investigated. The results of electrochemical measurements revealed that anodic and cathodic inhibitors inhibited galvanic corrosion by reducing the potential difference between the electrodes in two different ways. The values of corrosion potential and corrosion resistance of carbon steel increased after adding sodium N-lauroyl sarcosinate. In contrast, corrosion potential of stainless steel was shifted to the more negative region after adding zinc sulfate. X-ray photoelectron spectroscopy and scanning electron microscopy were applied to investigate the chemical compositions and morphologies of the films.

1H and 13C NMR investigation of conformational and aggregation behavior of sodium N-lauroyl sarcosinate

Complementary experiments with NMR 1H and 13C spectroscopy, proton diffusometry, and relaxometry have been used to investigate the sodium N-lauroyl sarcosinate (SLS) micellar systems in aqueous solutions. The effects of concentration and temperature on molecular conformation, micellar structure, and molecular kinetic in the SLS solutions were studied. Each NMR spectral line of the SLS spectrum splits but there are two variants of the effect: (i) for the head-groups this effect exists in the whole concentration range and it is due to the presence of two conformational isomers, (ii) for the hydrophobic part the splitting of resonance lines is observed in certain concentration range and caused by the existence of two different realizations of micellar aggregates. The concentration of the cis-conformers is a bit higher in a “monomer” (diluted) solution as well as the trans-conformers are more favorable in the micellar state. The relation of cis- and trans-conformer fractions is nearly independent of temperature. The transient concentration range, where different types of micellar sub-structures co-exist, is discovered. Moreover, the SLS solutions are characterized by four kinetic processes with different time scale.

Hyperhydration Effect on Pharmacokinetic Parameters and Detection Sensitivity of Recombinant Human Erythropoietin in Urine and Serum Doping Control Analysis of Males

Excessive fluid intake, that is, hyperhydration, may be adopted by athletes as a masking method during antidoping sample collection to influence the excretion patterns of doping agents and, therefore, manipulate their detection. The aim of this exploratory study was to assess the hyperhydration effect on the detection sensitivity of recombinant human erythropoietin (rHuEPO) by sodium N-lauroyl sarcosinate (“sarkosyl”) polyacrylamide gel electrophoresis analysis. The influence of hyperhydration on the serum and urinary pharmacokinetic (PK) profiles of rHuEPO was also investigated. Seven healthy physically active nonsmoking Caucasian males participated in a 31-day clinical study comprising a baseline (days 0, 1-3, and 8-10) and a drug phase (days 15-17, 22-24, and 29-31). Epoetin beta was administered subcutaneously at a single dose of 3000 IU on days 15, 22, and 29. Hyperhydration was applied in the morning on 3 consecutive days (days 1-3, 8-10, 22-24, and 29-31), that is, 0, 24, and 48 h after first fluid ingestion. Water and a commercial sports drink were used as hyperhydration agents (20 mL/kg body weight). Serum and urinary concentration-time profiles were best described by a one-compartment PK model with zero-order absorption. Delayed absorption was observed after hyperhydration and, therefore, lag time was introduced in the PK model. Results showed no significant difference (p > 0.05) on serum or urinary erythropoietin concentrations under hyperhydration conditions. A trend for decreasing volume of distribution and increasing clearance after hyperhydration was observed, mainly after sports drink consumption. However, no significant differences (p > 0.05) due to hyperhydration for any of the serum PK parameters calculated by noncompartmental PK analysis were observed. Renal excretion of endogenous erythropoietin and rHuEPO, as reflected on the urinary cumulative amount, was increased approximately twice after hyperhydration and this supports the nonsignificant difference on the urinary concentrations. Analysis of serum and urine samples was able to detect rHuEPO up to 72 h after drug administration. The detection window of rHuEPO remained unaffected after water or sports drink ingestion. Hyperhydration had no effect on the detection sensitivity of EPO either in serum or urine samples.

Rapid porcine corneal decellularization through the use of sodium N-lauroyl glutamate and supernuclease

Corneal decellularization represents a promising alternative source of human donor with global shortage. Multiple methods have been developed for the preparation of decellularized porcine corneal stroma. However, most strategies relied on long-time treatment to facilitate the entry of detergents or nucleases, which may cause irreversible ultrastructural damage. Here, we developed a rapid decellularization method for porcine corneal stroma through the combined mild detergent sodium N-lauroyl glutamate (SLG) and supernuclease. Compared with traditional methods, the novel decellularization method allowed the efficient removal of xenoantigen DNA within 3 h, while retaining the ultrastructure, transparency, and mechanical properties of porcine corneas. When transplanted in rabbit model for 1 month, the decellularized porcine corneal grafts presented favorable transparency and biocompatibility without immune rejection. Therefore, the combined use of detergent SLG and supernuclease may serve as a promising method for the clinical use of decellularized porcine cornea.

A comparison of the self-assembly behaviour of sodium N-lauroyl sarcosinate and sodium N-lauroyl glycinate surfactants in aqueous and aqueo-organic media

Self-assembly of surfactants is influenced by various intermolecular interactions and molecular structure, which dictate packing of molecules in the aggregate and its microstructure. Hydrogen-bonding between amide groups plays a key role in the self-assembly process of N-acyl amino acid surfactants (NAAS). The self-assembly properties of two NAAS, sodium N-lauroyl sarcosinate (SLS) and sodium N-lauroyl glycinate (SLG) that differ only in the head-group structure were compared in aqueous and aqueo-organic media by using a number of methods, including surface tension fluorescence, dynamic light scattering, calorimetry, and microscopy. It was observed that aggregate formation is more favoured in SLG. Studies revealed that while SLS formed small spherical micelles, SLG produced unilamellar vesicles in pH 7 buffer above critical micelle concentration at 25 °C. The stability of SLG vesicles with respect to pH and temperature was also investigated. Furthermore, both SLG and SLS were found to gelify aquo-organic mixtures of varying composition upon heat-cool treatment. Their gelation behaviour was compared by measuring minimum gelation concentration, molecular packing, and morphology and mechanical stability of the thermoreversible gels. The difference in self-assembly behaviour in water as well as in aqueo-organic mixtures was attributed to the steric repulsion and hydrogen-bonding interaction at the head-group of the molecules.

New and Green Multi-component Scaling and Corrosion Inhibitor for the Cooling Water of Central Air Conditioners

A green multi-component inhibitor was developed in this study to obtain suitable scale and corrosion inhibitor for the cooling water treatment of central air conditioners. The inhibitor formulation consisted of hydrolyzed polymaleic anhydride/Tween-80/sodium N-lauroyl sarcosinate/tolyltriazole (named 4-HTSA). Weight loss test and electrochemical method were used to investigate the corrosion inhibition performance of 4-HTSA on A3 carbon steel and T2 red copper in synthetic cooling water, and the scale inhibition performance of 4-HTSA was studied by the calcium carbonate precipitation method. The influence of parameters, such as pH, temperature, scaling and corrosive ion, on 4-HTSA was researched. Scanning electron microscopy (SEM) and x-ray diffraction were used for examination of the scale, and corrosion coupons were analyzed by SEM/energy-dispersive x-ray spectroscopy. Results showed that 4-HTSA had excellent scale and corrosion inhibition performance and wide tolerance to pH, temperature and the concentration of scaling and corrosive ion. Polarization curves indicated that 4-HTSA was anodic inhibitor.

The method of appearing solvent: Extraction of metal ions from aqueous solutions into in situ forming ionic liquid

The simultaneous dissolution of tetraoctylammonium bromide and sodium N-lauroyl sarcosinate in water leads to the in situ formation of a water-immiscible ionic liquid, tetraoctylammonium N-lauroyl sarcosinate. The new phase formed can extract cadmium, cobalt, copper, nickel, lead, and zinc ions from aqueous solution in the presence of 4-(2-pyridylazo)resorcinol (PAR), while it can extract cadmium ions in the absence of PAR.

The influence of some parameters on bubble average diameter in an electroflotation cell by laser diffraction method

The distribution of micro-bubbles generated by the electroflotation process has great importance in the flotation process for fine and ultrafine particles. The objective of this study was to evaluate the influence of some parameters on the average bubble size, generated in an electroflotation cell, on 316 stainless steel cathodes with different geometries, surface finishing, and a Ti/RuO2 mesh as an anode, by the laser diffraction method and image analysis. The average bubble size determination was conducted at different pH values, different cathode surfaces, and different types of collector. Results show that an increase in pH and current density led to a decrease of the bubble size, and that mesh electrodes and electrodes polished with coarser grit sandpaper give smaller gas bubbles. Conversely, when Flotigam EDA, sodium N-lauroyl sarcosinate or sodium oleate were added, larger bubbles were observed. Under the conditions of generation of small bubbles, higher recoveries of fine phosphate particles were observed.

Solubility enhancement of phenanthrene using novel chelating surfactant

AbstractA novel chelating surfactant denoted as sodium N-lauroyl ethylenediamine triacetate (N-LED3A) with both surface activity and chelation functions was studied for phenanthrene (PHE) solubilisation ability. The critical micelle concentration (CMC) of N-LED3A was measured, and the effects of the initial N-LED3A concentration, temperature, pH value and coexisting ions (Na

Potential of biocompatible regenerated silk fibroin/sodium N-lauroyl sarcosinate hydrogels

Hydrogels are becoming widely used in biomaterial applications. The available methods for the preparation of these materials are continually growing. The gelation time (GT) of silk protein fibroin is difficult to control by physical methods. The cross-linkers used in available chemical techniques are likely to impact the biocompatibility of the resultant materials. In this paper, we demonstrate that the addition of sodium N-lauroyl sarcosinate (an amino-acid-based surfactant) accelerates the formation of hydrogels from fibroin. GT, turbidity variations, changes of viscoelasticity during the gelation process, and the mechanical properties of the products are measured. The secondary structure was probed by Fourier transform infrared spectroscopy, X-ray diffraction and the morphologies of the products were investigated by scanning electron microscopy. Transformations in the β-sheet content were monitored by the fluorescence of Thioflavine T and circular dichroism measurements. The relationship between the surface tension of sodium N-lauroyl sarcosinate and the GT was also explained. To investigate cell compatibility, fibroblast cells were seeded onto the surface of the hydrogels. The results indicate that the sodium N-lauroyl sarcosinate/fibroin GT can be controlled. This blend-hydrogel demonstrates excellent cell compatibility, good compression strength, and outstanding compression-recovery characteristics. Sodium N-lauroyl sarcosinate/silk fibroin hydrogels containing β-sheets have considerable potential as replacement materials in addressing the tissue defects involved with repair surgery.

Excellent Cell Compatibility in Time Controlled Silk Fibroin Hydrogels

Various methods were developed to prepare hydrogels including photo-cross-linking, chemical cross-linking, enzymatic cross-linking, pH or temperature-induced gelation, ionic interaction, and hydrophobic interactions. Whereas silk fibroin gelation time was difficult to control by physical methods, the cross-linkers used in chemical technique were likely to reduce the cell biocompatibility. Sodium N-Lauroyl Sarcosinate (SNS), an amino acid-based surfactant, came into accelerate silk fibroin to form silk hydrogel. To monitor the gelation process and determine the gelation time, turbidity changes during gelation were measured by Synergy HT. Cylindrical gels have been measured with universal material experiment machine and KES for mechanical properties. Fibroblast (L929) cells were seeded on the surface of hydrogels to investigate the cell compatibility. The results show that the SNS/SF gelation time ranges from 20 min to 120 min, which is affected by environment temperature, the final concentrations of SF and SNS. Compared with pure silk fibroin hydrogels, the compression strength of SNS/SF gel is much stronger. SNS/SF gel has excellent compression-recovery performance in KES test as well. A logarithmic stable cell growth appears on the surface of SNS/SF hydrogels, which indicates that SNS/SF hydrogels have excellent cell compatibility. Therefore, the SNS/SF hydrogels have great potential in tissue repair for surgery.

Extracting DNA from within intact foraminiferal shells

Abstract Here we present an evaluation of several methods for extracting DNA from within intact foraminiferal shells. We tested 12 lysis buffers under carefully optimised incubation conditions, evaluating their success in terms of efficiency in evacuating cellular material, crude DNA yield, PCR success, and final shell integrity. A number of the buffers tested produced excellent results. The most successful method utilized a lysis buffer containing Sodium N-lauroyl sarcosine, Guanidinium isothiocyanate, Isopropanol, TRIS and NaCl, incubated at 75 °C for 24 h, followed by chloroform extraction and ethanol precipitation. High yields of DNA were produced, with no signs of PCR inhibition, and the foraminiferal shells were left completely intact. Retaining the shell of individual specimens presents a significant advance, allowing for direct comparisons between shell morphology and genotype data, which could greatly enhance the utility of foraminifera as palaeoproxies of past climate change.

Phosphorylation of Thyroid Hormone Receptor-associated Nuclear Receptor Corepressor Holocomplex by the DNA-dependent Protein Kinase Enhances Its Histone Deacetylase Activity

It is well documented that unliganded thyroid hormone receptor (TR) functions as a transcriptional repressor of specific cellular target genes by acting in concert with a corepressor complex harboring histone deacetylase (HDAC) activity. To fully explore the cofactors that interact with the transcriptionally repressive form of TR, we biochemically isolated a multiprotein complex that assembles on a TR.retinoid X receptor (RXR) heterodimer in HeLa nuclear extracts and identified its polypeptide components by mass spectrometry. A subset of TR.RXR-associated polypeptides included NCoR, SMRT, TBL1, and HDAC3, which represent the core components of a previously described NCoR/SMRT corepressor complex. We also identified several polypeptides that constitute a DNA-dependent protein kinase (DNA-PK) enzyme complex, a regulator of DNA repair, recombination, and transcription. These polypeptides included the catalytic subunit DNA-PKcs, the regulatory subunits Ku70 and Ku86, and the poly(ADP-ribose) polymerase 1. Density gradient fractionation and immunoprecipitation analyses provided evidence for the existence of a high molecular weight TR.RXR.corepressor holocomplex containing both NCoR/SMRT and DNA-PK complexes. Chromatin immunoprecipitation studies confirmed that unliganded TR.RXR recruits both complexes to the triiodothyronine-responsive region of growth hormone gene in vivo. Interestingly, DNA-PKcs, a member of the phosphatidylinositol 3-kinase family, was found to phosphorylate HDAC3 when the purified TR.RXR.corepressor holocomplex was incubated with ATP. This phosphorylation was accompanied by a significant enhancement of the HDAC activity of this complex. Collectively, our results indicated that DNA-PK promotes the establishment of a repressive chromatin at a TR target promoter by enhancing the HDAC activity of the receptor-bound NCoR/SMRT corepressor complex.

Bacterial Decolorization of Acid Orange 7 in the Presence of Ionic and Non-Ionic Surfactants

The effects of the non-ionic surfactant Triton X-100, the cationic surfactant cetyltri-methylammonium bromide (CTAB) and the anionic surfactant sodium N-lauroyl sarcosinate (SLS) on the decolorization of the reaction medium containing the monoazo dye Acid Orange 7 (AO7) by Alcaligenes faecalis and Rhodococcus erythropolis were studied. It was found that the surfactants influenced in different ways the rate of decolorization. At all concentrations tested the non-ionic surfactant Triton X-100 decreased the decolorization rate of R. erythropolis. At concentrations above the critical micelle concentration (CMC) Triton X-100 upset the usually observed exponential decay of the dye with A. faecalis due probably to the existence of an outer membrane in this organism. In concentrations above the CMC the anionic surfactant SLS inhibited the decolorization and, at prolonged incubation, caused partial release of the bound dye. The cationic surfactant CTAB in concentrations above and below the CMC accelerated drastically the binding of AO7 to the cells causing a rapid staining of the biomass and complete decolorization of the reaction medium. An attempt was made for explanation of the observed differences by the negative electrostatic charge of the living bacterial cell.

Synergistic fungicidal activity of Cu 2+ and allicin, an allyl sulfur compound from garlic, and its relation to the role of alkyl hydroperoxide reductase 1 as a cell surface defense in Saccharomyces cerevisiae

Cu 2+ showed a dose-dependent fungicidal activity against Saccharomyces cerevisiae cells, and its lethal effect was extremely enhanced in the presence of allicin, an allyl sulfur compound from garlic. The fungicidal activity of Cu 2+ was unaffected or rather attenuated by other sulfur-containing compounds such as N-acetyl-cysteine, l-cysteine or dithiothreitol. Ca 2+ could absolutely protect against the lethal effect of Cu 2+ itself, but showed no protection against the fungicidal activity of Cu 2+ newly generated in combination with allicin. Cu 2+ accelerated an endogenous generation of reactive oxygen species (ROS) in S. cerevisiae cells at a lethal concentration, but such intracellular oxidative stress induction was not observed during cell death progression upon treatment with Cu 2+ and allicin. A surfactant, sodium N-lauroyl sarcosinate (SLS), enhanced the solubilization of a few proteins including alkyl hydroperoxide reductase 1 (AHP1) in intact cells, accounting for the absence of this protein in the extract from allicin-treated cells. Allicin-treated cells were rendered extremely sensitive to the subsequent Cu 2+ treatment as in the case of SLS-treated cells. Allicin-treated cells and SLS-treated cells similarly showed an increased sensitivity to exogenously added tert-butyl hydroperoxide ( t-BOOH), an organic peroxide that is detoxified by the action of AHP1. Our study suggests that allicin influences the mode of cell surface localization or the related function of AHP1 as a defense against phospholipid peroxidation by the external action of Cu 2+.

Conformational change, aggregation and fibril formation induced by detergent treatments of cellular prion protein

The conversion of protease-sensitive prion protein (PrP-sen) to a high beta-sheet, protease-resistant and often fibrillar form (PrP-res) is a central event in transmissible spongiform encephalopathies (TSE) or prion diseases. This conversion can be induced by PrP-res itself in cell-free conversion reactions. The detergent sodium N-lauroyl sarkosinate (sarkosyl) is a detergent that is widely used in PrP-res purifications and is known to stimulate the PrP-res-induced conversion reaction. Here we report effects of sarkosyl and other detergents on recombinant hamster PrP-sen purified from mammalian cells under oxidizing conditions that maintain the single native disulfide bond. Low concentrations of sarkosyl (0.001-0.1%) induced aggregation of PrP-sen molecules, increased light scattering, altered fluorescence excitation and emission spectra, and enhanced the proportion of beta-sheet secondary structure according to circular dichroism and infrared spectroscopies. An enhancement of beta-sheet content was also seen with 0.001% sodium dodecyl sulfate (SDS) but not several other types of detergents. Electron microscopy revealed that sarkosyl induced the formation of both amorphous and fibrillar aggregates. The fibrils appeared to be constructed from spherical bead-like protofibrils. Neither TSE infectivity nor the characteristic partial proteinase K resistance of PrP-res was detected in the sarkosyl-induced PrP aggregates. We conclude that certain anionic detergents can disrupt the conformation of PrP-sen and induce high beta-sheet aggregates that are distinct from scrapie-associated PrP-res in terms of protease-resistance, infrared spectrum and infectivity. These results reinforce the idea that not all high-beta aggregates of PrP are equivalent to the pathologic form, PrP-res.

Characterization of chemical selectivity in micellar electrokinetic chromatography: V. The effect of the surfactant hydrophobic chain

The influence of the surfactant hydrophobic chain on selectivity in micellar electrokinetic chromatography was investigated using two sets of surfactants. A series of three sarcosinate surfactants (sodium N-lauroyl sarcosinate, sodium n−myristoyl sarcosinate, and sodium N-parmitoyl sarcosinate) with C11, C13, and C15 hydrocarbon tails were compared. In addition, sodium dodecyl sulfate and sodium tetradecyl sulfate were investigated to determine the chain length effect for sodium sulfate surfactants. Linear solvation energy relationships as well as free energy of transfer studies were used to predict the selectivity differences. The results suggest that although the surfactant chain length can have some effect, the magnitude of this influence seems to be dependent on the head group. © 2000 John Wiley & Sons, Inc. J Micro Sep 12: 433–441, 2000

Use of several anionic surfactants for the separation of aniline derivatives in micellar electrokinetic chromatography

The separation of 13 aniline derivatives by micellar electrokinetic chromatography (MEKC) with four anionic surfactants was demonstrated. We used sodium dodecyl sulfate (SDS), sodium N-lauroyl- N-methyl-β-alaninate (ALE), sodium N-lauroyl- N-methyltaurate (LMT) and sodium laurylsulfoacetate (LSA) as surfactants. The first application of LSA to MEKC was described. The surfactants having amido linkages, ALE and LMT, gave better separation than SDS. LSA has an ester linkage and its ionic group is sulfonate. Separation with LSA was also better than that with SDS. LSA showed different selectivity from the other surfactants. The effect of the linkages on migration behavior was investigated.

The contribution of cytotoxicity to DNA-effects in the single cell gel test (comet assay)

We evaluated genotoxic and cytotoxic effects of the three non-mutagenic and non-carcinogenic compounds p-nitrophenol, d-menthol and sodium N-lauroyl sarcosine which have previously been shown to induce DNA double strand breaks (DNA dsb) secondary to induced cytotoxicity. We tested wheter genotoxic effects in the alkaline single cell gel test (comet assay) may be confounded by cytotoxicity-induced DNA dsb. Cell viability was determined at the end of the treatment using the fluorescein diacetate/ethidium bromide-assay and plating efficiency was used as an indicator of long-term survivability. Experiments with V79 Chinese hamster cells and human white blood cells revealed negative results in the comet assay despite strong cytotoxic effects. However, cells with extremely fragmented DNA (‘clouds’) occured but were excluded from the evaluation under the principle that they represent dead cells. We also noticed a significant loss of cells at cytotoxic concentrations that might be attributed to the induction of highly fragmented DNA which is lost during electrophoresis. Since the comet assay allows the determination of DNA effects on the single cell level, a confounding effect of cytotoxicity on test results can be avoided.

Characterization of a serum factor that decreases albumin mRNA in cultured hepatocytes.

When primary cultures of hepatocytes are exposed to media containing fetal bovine serum (FBS) there is a rapid decrease in levels of tissue-specific mRNAs such as albumin mRNA. We used Northern blot analysis to examine mRNA levels in cultured hepatocytes, and characterized the factor in FBS that significantly reduces the steady state albumin mRNA level. Neonatal bovine serum or serum derived from platelet-poor calf plasma proved as potent as did FBS, but commercial bovine serum albumin did not exhibit this inhibitory activity. Inhibitory activity of FBS was not removed by moderate heat treatment, dialysis, or extraction with organic solvents. However, incubation of FBS with a highly anionic detergent such as 0.1% sodium dodecyl sulfate or N-lauroyl sarcosine, followed by extensive dialysis, resulted in sera that did not inhibit expression of albumin mRNA. These sera supported cell attachment and seemed non-toxic toward the cells. Ammonium sulfate fractionation of FBS showed the activity was present in the 45 to 70% fraction, and trypsin digestion destroyed the inhibitory activity. Gel exclusion chromatography gave a molecular weight of 60,000 to 70,000. Fractionation of serum proteins by DEAE-Sephacel or Cibacron blue-agarose showed enrichment for albumin in the most active fractions. Interestingly, metabolic labeling of secreted and cellular proteins with 35S-methionine and cysteine showed no significant difference between hepatocytes maintained for 2 days beforehand in serum-free or serum-supplemented media, and no difference between detergent-treated FBS and control FBS.(ABSTRACT TRUNCATED AT 250 WORDS)