bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of alcohol‐free microemulsion systems containing fatty acids as cosurfactants
Authors: Lohateeraparp Prapas , Wilairuengsuwan Pongtai , Saiwan Chintana , Sabatini David A. , Harwell Jeffrey H. 
Published: November 2006

AbstractIn this study, fatty acids with carbon chains ranging in length from 3 to 8 (propyl to octyl) were used in place of alcohols to form microemulsion systems. The microemulsion systems contained sodium dodecyl sulfate (SDS), hexane, fatty acid, water, and NaCl. The phase behavior of these systems was examined using salinity scans at 25°C. The results showed that propanoic and butanoic acids promoted the formation of clear isotropic microemulsions, whereas the other fatty acids promoted a gel formation. High hexane solubilization was obtained with all of the systems. The optimum solubilization parameter (SP*) and optimum salinity (S*) decreased with increasing SDS concentration. With increasing fatty acid chain length, S* decreased but SP* increased. Conductivity meausrements showed that, during the salinity scan, the conductivity of the systems was relatively unchanged, gradually decreased, or was a maximum at a given value. Interfacial tension (IFT) measurements showed that ultralow IFT were realized between microemulsion and oil phases using the fatty acids and that SP* and IFT were inversely related. The results of this study confirm that microemulsions can be formulated without alcohols through replacement of the alcohols with the appropriate fatty acids.
Surface and thermodynamic properties of diquaternary bola‐form amphiphiles containing an aromatic spacer
Authors: Negm Nabel A. , Mohamed Ammona S. 
Published: November 2006

AbstractA series of diquaternary ammonium bromides having phenyl groups with different (CH2/N+) ratios were synthesized. The critical micelle concentration of each amphiphile was determined using equilibrium surface tension and equivalent conductance data. Air/water interfacial parameters were measured at 20, 35, and 50°C. The surface tension isotherms of the different diquaternary amphiphiles showed two region of discontinuity corresponding to two critical micelle concentrations. The first was related to the spherical nature of the micelles, whereas the second was related to the multiple loops of the lamellar aggregates. The prepared compounds were evaluated as a new class of diquaternary ammonium compounds for future application in protection of steel fabrics against aggressive media (2 N HCl). The results showed that the prepared amphiphiles offered good corrosion inhibition efficiency. Also, increasing the hydrophobic chain length and/or concentration increased their efficiency.
Surface properties of surfactants derived from natural products. Part 1: Syntheses and structure/property relationships—Solubility and emulsification
Authors: Piispanen Peter S. , Persson Marcus , Claesson Per , Norin Torbjörn 
Published: November 2006

AbstractSeveral novel and some previously known, mostly sugar‐based, surfactants have been synthesized and some of their surface properties have been characterized and compared with those of commercial nonylphenol ethoxylates. The surfactant solubility in water, ethanol, and dodecane was studied. The properties of these compounds as emulsification agents in systems composed of the surfactant with water/isopropyl myristate, water/rapeseed oil, and water/dodecane are presented. The aqueous solubility of the surfactants follows the general trend expected from their hydrophilic‐lipophilic balance according to Griffin (HLBG), but it is also clear that the nature of the headgroup and the structure of the nonpolar part affect the solubility in a manner not aptured in the standard HLBG concept. An ester or amine group as the connecting unit between the hydrophile and the hydrophobe produces a more water‐soluble surfactant than the corresponding amide derivative. Some effective emulsifiers were found. For instance, the surfactants with a dehydroabietic nonpolar group appear to be promosing emulsifiers. Most sugar‐based surfactants were able to form macroemulsions of up to around 2 wt/vol% of oil. The stability of many of these amulsions was very high, extending for months.
Glucamine‐based gemini surfactants I: Gemini surfactants from long‐chainN‐alkyl glucamines and α,ω‐diepoxides
Authors: Warwel S. , Brüse F. , Schier H. 
Published: November 2006

AbstractN‐Alkyl glucamines can be reacted with α,ω‐diepoxides to yield gemini (dimeric) surfactants similarly to the reaction of glucamine with terminal epoxides. Under the conditions chosen for this work, epoxides were quantitatively converted in the presence of an equimolar amount of amine to gemini surfactants. Reactions could be carried out under mild conditions (70°C) in methanol, and products were obtained quantitatively by removing the solvent. The combination ofN‐octyl glucamine,N‐decyl glucamine, orN‐dodecyl glucamine with diepoxides of α,ω‐diolefins having chain lengths of C8, C9, C10, or C14resulted in gemini surfactants differing in spacer length and length of hydrophobic alkyl chains. Surface‐active properties were studied by measuring surface tension and evaluating foaming properties. Tensiometric studies showed the reduction of surface tension down to 29–33 mN/m and critical micelle concentrations often in the range of 3–150 mg/L. Comparison of a selected gemini surfactant [1,8‐bis(N‐dodecyl glucamino‐2,7‐octane diol] with its corresponding “single surfactant” demonstrated the enhancement of surface‐active properties afforded by the gemini structure.
Surfactant properties of low molecular weight phospholipids
Authors: Weschayanwiwat Punjaporn , Scamehorn John F. , Reilly Peter J. 
Published: November 2006

AbstractSurface tensions, critical micelle concentrations (CMCs), contact angles on hydrophobic polyethylene, and foaming characteristics of phosphatidic acids, phosphatidylcholines, phosphatidylethanolamines, and phosphatidylglycerols were measured to determine their suitability as substitutes for traditional surfactants. These phospholipids have fatty acid chains of 5 to 12 carbon atoms, a range over which they are soluble at room temperature. Their surface tensions decrease with increasing concentrations until their CMCs are reached, above which their plateau surface tensions are as low as 21 mN/m, indicating excellent surface activities. In general, plateau surface tensions decrease with increasing chain length within each phospholipid type. The classical relationship for In CMC vs. chain length is followed with slopes typical of anionic surfactants for phosphatidic acids and phosphatidylglycerols and resembling zwitterionic surfactants for phosphatidylcholines and phosphatidylethanolamines, consistent with the charge on the hydrophilic group. The wetting capabilities of aqueous solutions on polyethylene are good and foam heights and stabilities are high, the latter two properties being comparable to traditional anionic (sodium dodecylsulfate) and nonionic (octylphenol polyethoxylate) surfactants. Some anomalies are observed regarding the effect of chain length on wetting and foaming, probably due to the depletion effect. Many phospholipids slowly degrade in aqueous solution. We conclude that short‐chain phospholipids exhibit excellent surfactant properties and may be useful in many applications.
Synthesis and properties of new cationic surfactants: 1‐Alkylthiomethyl‐3‐carbamoylpyridinium chlorides
Authors: Pernak Juliusz , Zygadło Małgorzata , Cieniecka‐Rosłonkiewicz Anna 
Published: November 2006

Abstract1‐Alkylthiomethyl‐3‐carbamoylpyridinium and 1‐alkylthiomethyl‐4‐carbamoylpyridinium chlorides were prepared by the reaction of nicotinamide or isonicotinamide with chloromethyl alkyl sulfides. The obtained chlorides were examined for their antimicrobial activities. 4‐Carbamoyl‐1‐dodecylthiomethylpyridinium chloride exhibited strong antimicrobial activity, similar to the activity of benzalkonium chloride. All synthesized chlorides underwent hydrolysis in aqueous solutions at temperatures higher than 70–75°C. In aqueous solution 1‐alkylthiomethyl‐3‐carbamoylpyridinium chlorides reacted with ozone. A new generation of cationic surfactants that were hydrolyzed and ozone‐reactive in an aqueous solution was synthesized during this study.
Role of partitioning site in producing viscoelasticity in micellar solutions
Authors: Kumar Sanjeev , Sharma Damyanti , Kabir‐ud‐Din  
Published: November 2006

AbstractThe effect of the addition of four aromatic compounds (anthranilic acid, benzoic acid, sodium anthranilate, and sodium benzoate) to 10 mM cetyltrimethylammonium bromide solutions is investigated by 1H nuclear magnetic resonance spectroscopy. The site of solubilization of these molecules inside the micelle is inferred. It is shown that sodium anthranilate, which partitions near the head group region together with the external part of the micellar palisade layer (in Rosen's terminology), is most effective in producing micellar growth (or viscoelasticity). In this context a deeper penetration of an additive inside the micelle disqualifies it to produce viscoelasticity in the system. Furthermore, interior or palisade region solubilization depends on the nature of groups attached to the main benzene ring.
Determination of average molecular weight of commercial surfactants: Alkylpolyglucosides and fatty alcohol ethoxylates
Authors: Bravo Rodriguez V. , Jurado Alameda E. , Reyes Requena A. , García López A. I. , Bailón‐Moreno R. , Cuevas Aranda M. 
Published: November 2006

AbstractA quick and simple method, based on elemental and moisture analyses, is proposed for estimating the mean molecular weight of alkylpolyglucosides and fatty alcohol ethoxylates, which are nonionic surfactants that are attracting growing interest for their ease of biodegradation. Analyses for the water content and the elemental composition were carried out for three alkylpolyglucosides (Henkel‐Cognis): Glucopon 215, Glucopon 600, and Glucopon 650, as well as for five fattyalcohol ethoxylates (Kao Corporation): FINDET 10/15, FINDET 10/18, FINDEt 1214N/16, FINDET 1214N/23, and FINDET 1618/A18. Application of the method requires knowing the mean number of carbons in the fatty acid chains of the surfactant. This number, in the case of the alkylpolyglucosides assayed here, has been determined experimentally by high‐performance liquid chromatography.
Mechanism of the enhanced spreading of some mixtures of anionic and cationic hydrocarbon chain surfactants on a highly hydrophobic polyethylene surface
Authors: Rosen Miltion J. 
Published: November 2006

AbstractThe objective of this investigation was to measure the interfacial properties and interactions among mixtures of different cationic and anionic surfactants at the hydrophobic solid/aqueous solution interface to explain the different spreading factors or behavior of the mixed surfactants on a highly hydrophobic polyethylene (PE) film. A synergistic effect in the spreading of the mixed surfactant solutions on the PE film was observed when the surfactants were added sequentially. Other interfacial phenomena related to this surfactant spreading, such as interaction parameters at the solid/liquid (S/L) and liquid/air (L/A) interfaces in the mixtures adsorbed at various interfaces and dynamic contact angles of the mixed surfactant solutions during the process of spreading on the PE substrate, were investigated to obtain insight into this enhanced spreading. All the interaction parameters were more negative than −20, indicating very strong interaction between these cationic and anionic surfactants. The interaction parameters at the S/L interface were more negative than at the L/A interface, showing that the attractive interaction at the S/L interface was stronger than at the L/A interface. The spreading was related to the difference in the interaction parameters at the S/L and L/A interfaces and to the dynamic contact angle.
Phase behavior of a fragrance compound system: Water/phenethyl alcohol/laureth 4/glycerol
Authors: Friberg Stig E. , Al‐Bawab Abeer , Sandburg Joel D. , Barber Jennifer L. , Yin Qi , Aikens Patricia A. 
Published: November 2006

AbstractThe phase diagram of the system water/phenethyl alcohol (PEA)/Laureth 4 (L4)/glycerol was determined using visual observation, optical microscopy, small‐angle X‐ray diffractometry, and the vapor pressure of phenethyl alcohol measured by gas chromatographic analysis of headspace vapor at equilibrium. The phase diagram was shown to be dominated by three narrow isotropic liquid solubility regions along the water/glycerol, glycerol/PEA, and PEA/L4 axes. Vapor pressure measurements and tie‐line determinations showed the final state of formulations after evaporation of water to be emulsions of glycerol/PEA‐in‐L4/PEA or L4/PEA‐in‐glycerol/PEA. PEA was predominantly dissolved in the L4/PEA phase because the chemical potential of PEA in glycerol was high, even at modest concentrations.
Soil release polymers
Authors: O'Lenick Anthony J. 
Published: November 2006

AbstractCleaning today's fabrics requires a sophisticated formulated product that is (i) consumer friendly, (ii) environmentally friendly, (iii) effective with a broad range of fabrics, (iv) effective at accepted wash temperatures, (v) effective with a variety of washing machines, and (vi) cost effective. Today “cleaning” includes not only removal of soils but also provision to the consumer of an appropriate hand and improved fabric cleanability in subsequent washings. It is therefore not surprising that the complexity of today's detergents has increased significantly over the last generation. Antiredeposition agents and soil release polymers have become important additives to today's laundry products.
Method to produce 9(S)‐hydroperoxides of linoleic and linolenic acids by maize lipoxygenase
Authors: Gardner Harold W. , Grove Marilyn J. 
Published: November 2006

AbstractSeed from maize (corn) Zea mays provides a ready source of 9‐lipoxygenase that oxidizes linoleic acid and linolenic acid into 9(S)‐hydroperoxy‐10(F), 12(Z)‐octadecadienoic acid and 9(S)‐hydroperoxy‐10(E), 12(Z), 15(Z)‐octadecatrienoic acid, respectively. Corn seed has a very active hydro‐peroxide‐decomposing enzyme, allene oxide synthase (AOS), which must be removed prior to oxidizing the fatty acid. A simple pH 4.5 treatment followed by centrifugation removes most of the AOS activity. Subsequent purification by ammonium sulfate fractional precipitation results in negligible improvement in 9‐hydroperoxide formation. This facile alternative method of preparing 9‐hydroperoxides has advantages over other commonly used plant lipoxygenases.
Inhibition of purified pig and human liver retinyl ester hydrolase by pharmacologic agents
Authors: Schindler Rainer 
Published: November 2006

AbstractIdentification of inhibitors of retinyl ester hydrolase (RFH) would help to elucidate its role in vitamin A metabolismin vivo. By using standard incubation conditions, the effects of 215 drugs as potential inhibitors of purified pig and human liver REH when acting on micellar substrate retinyl palmitate were evaluated at 16.7, 167, and 1670 μM. Out of the compounds tested, 103 were inhibitors of the pig liver enzyme. The most potent compounds, in order of decreasing activity, were chloral hydrate, lovastatin, phytomenadione, alimemazine, physostigmine, thioridazine, phenoxybenzamine, probucol, cinnarizine, cyclandelate, amiodarone, flupenthixol, and naftidrofuryl; this order is roughly similar to that of their inhibition of human liver REH. Of the 10 tricyclic ring‐containing drugs tested, alimemazine was the most potent enzyme inhibitor. The concentrations necessary for 50% enzyme inhibition ranged from <2.6 up to >540 μM. Moreover, inhibitory kinetic studies showed that at least two pharmaceutica's, chloral hydrate and amiodarone, are potent REH inhibitors at therapeutically achievable serum concentrations. First‐pass metabolites were inactive as REH inhibitors compared to that of the parent compounds, in the cases of chloral hydrate, lovastatin, and cyclandelate.
Necrosis and apoptosis in lymphoma cell lines exposed to eicosapentaenoic acid and antioxidants
Authors: Heimli Hilde , Finstad Hanne S. , Drevon Christian A. 
Published: November 2006

AbstractThe present study is focused on the role of oxidative stress in the induction of either necrosis or apoptosis by eicosapentaenoic acid (EPA) in the lymphoma cell lines Raji and Ramos, respectively. To investigate the different death modes induced by EPA, we assessed the importance of some antioxidants and reactive oxygen species in the two cell lines. We observed that different antioxidants counteracted the necrotic effect of EPA on Raji cells to a different extent, and that vitamin E counteracted EPA‐induced accumulation of superoxide anion in this cell line. On the contrary, no effects of antioxidants were observed on development of apoptosis induced by EPA in Ramos cells, and vitamin E did not counteract EPA‐induced accumulation of superoxide anions in Ramos cells. Moreover, apoptosis was partly inhibited by transcription inhibitors (actinomycin D) and protein synthesis inhibitors (cycloheximide), suggesting dependency upon new protein synthesis prior to apoptosis. Kinase inhibitors (staurosporin and calphostin C) did not alter the EPA‐induced apoptosis. The observed cellular accumulation of superoxide anion following EPA incubation may be important for induction of necrosis in Raji cells. In contrast, none of the other investigated parameters indicated a role of oxidative stress promoted by EPA in the induction of apoptosis in Ramos cells.
Effect of 4‐hydroxy‐2(E)‐nonenal on soybean lipoxygenase‐1
Authors: Gardner Harold W. , Deighton Nigel 
Published: November 2006

AbstractThe oxidation of linoleic acid by soybean lipoxygenase‐1 (LOX‐1) was inhibited in a time‐dependent manner by 4‐hydroxy‐2‐(E)‐nonenal (HNE). Kinetic analysis indicated the effect was due to slow‐binding inhibition conforming to an affinity labeling mechanism‐based inhibition. After 25 min of preincubation of LOX‐1 with and without HNE, Lineweaver‐Burk reciprocal plots indicated mixed noncompetitive/competitive inhibition. Low concentrations of HNE influenced the electron paramagnetic resonance (EPR) signal of 13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid (13‐HPODE)‐generated Fe3+‐LOX‐1 slightly, but higher concentrations completely eliminated the EPR signal indicating an active site hindered from access by 13‐HPODE. HNE may compete for the active site of LOX‐1 because its precursor, 4‐hydroperoxy‐(2E)‐nonenal, is a product of LOX‐1 oxidation of (3Z)‐nonenal. Also, it was an attractive hypothesis to suggest that HNE may disrupt the active site by forming a Michael adduct with one or more of the three histidines that ligate the iron active site of LOX‐1.
Transformations of DHEA and its metabolites by rat liver
Authors: Lardy Henry , Marwah Ashok , Marwah Padma 
Published: November 2006

AbstractBecause dehydroepiandrosterone (DHEA) has a wide variety of weak beneficial effects in experimental animals and humans, we searched for metabolites of this steroid in the hope of finding more active compounds that might qualify for the title “steroid hormone”. Incubation of DHEA with rat liver homogenate fortified with energy‐yielding substrates resulted in rapid hydroxylation at the 7α‐position of the molecule and subsequent conversion to other 7‐oxygenated steroids in the sequence DHEA»7α‐hydroxyDHEA»7‐oxoDHEA»7β‐hydroxyDHFA, with branching to diols, triols, and sulfate esters. The ability of these metabolites to induce the formation of liver thermogenic enzyme activity increased from left to right in that sequence. A total of 25 different steroids were characterized, and at least six additional structures that are currently under study were produced from DHEA. 7‐OxoDHEA is more effective than DHEA in enhancing memory performance in old mice and in reversing the amnesic effects of scopolamine.
Hepatic Δ9, Δ6, and Δ5 desaturations in non‐insulin‐dependent diabetes mellitus eSS rats
Authors: Montanaro Mauro A. , Rimoldi Omar J. , Igal R. Ariel , Montenegro Silvana , Tarres María C. , Martínez Stella M. , Brenner Rodolfo R. 
Published: November 2006

AbstractBoth diabetes mellitus type 1 and diabetes mellitus type 2 are widespread diseases that alter carbohydrate and lipid metabolism. e Stilmann‐Salgado (eSS) rats are experimental animals that spontaneously evolve to a state similar to that of young people affected by non‐insulin‐dependent diabetes mellitus (NIDDM; type 2). Using 6‐mon‐old eSS rats that, according to the literature [Martinez, S.M., Tarrés, M.C., Montenegro, S, Milo, R., Picena, J.C., Figueroa, N., and Rabasa, S.R. (1988) Spontaneous Diabetes in eSS Rats, Acta Diabetol. Lat. 25, 303–313], had already developed insulin resistance, we investigated the changes evoked on Δ9, Δ6, and Δ5 liver desaturases. The abundance of mRNA and enzymatic activities were measured, as well as the FA composition of liver microsomal lipids. Compared to control rats, the mRNA content and activity of SCD‐1 (stearoyl CoA‐desaturase, isoform of the Δ9 desaturase) were significantly higher, urase, isoform of the Δ9 desaturase) were significantly higher, whereas the mRNA and activities of Δ6 and Δ5 desaturases were not significantly modified. Correspondingly, the proportion of 18∶1n−9 and the ratios of 18∶1n−9/18∶0 and 16∶1/16∶0 in lipids were significantly increased, whereas the proportion of 20∶4n−6 was unaltered. These effects were found while glycemia was constant or increased. The results are completely opposite those described in insulin‐dependent diabetes mellitus (type 1), in which a depression of all the desaturases is found. They suggest that in eSS rats, the activities of the desaturases were not modified by an insulin‐resistance effect. Moreover, we suggest that the enhancement of SCD‐1 activity might be considered as another typical sign of the NIDDM syndrome, because it has also been found in other animal models of NIDDM, for example, the ones evoked by the sucrose‐rich diet and in the Zucker rat.
Comparison of effects of U18666A and enantiomeric U18666A on sterol synthesis and induction of apoptosis
Authors: Cenedella Richard J. , Sexton Patricia S. , Krishnan Kathiresan , Covey Douglas F. 
Published: November 2006

AbstractTreatment of animals or cells with the amphipathic tertiary amine U18666A {3β‐[2‐(diethylamino) ethoxy]androst‐5‐en‐17‐one} provides models for several human diseases (e.g., cataracts, Niemann‐Pick disease, and epilepsy). Although U18666A can inhibit several enzymes in the cholesterol synthesis pathway, we hypothesized that induction of these varied conditions was due to physical effects of the amine rather than to inhibition of specific proteins. To test this possibility we compared the capacity of U18666A and its enantiomer, ent‐U18666A, to inhibit net sterol synthesis and induce apoptosis in cultured bovine lens epithelial cells. Nonenantiospecific actions dependent on the physical properties of these mirror image molecules would be identical, but effects dependent upon enantiospecific interactions would be different for the enantiomers. At the same concentrations, both forms of the compound equally inhibited sterol synthesis and induced apoptosis. These observations supported a generalized mechanism of enzyme inhibition such as perturbation of the microenvironment of endoplasmic enzymes and alteration of membrane order, perhaps of the mitochondrial membrane, to explain induction of apoptosis.