Effects of Keratin and Lung Surfactant Proteins on the Surface Activity of Meibomian Lipids
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In vitro studies indicate that surface tension and surface viscosity of the tear film lipid layer (TFLL) are governed by interactions between meibomian lipids and proteins from the aqueous layer. The role of minor tear proteins with strong lipophilic properties or those correlated with pathological states is still unknown. The discovery of lung surfactant proteins (SPs) in tears and keratin in normal and abnormal meibomian gland excretions warrants investigation into their effects on the surface activity of meibomian lipid films.Commercial keratin and bovine lung SPs were used in vitro to assess the surface pressure of meibomian lipid films using a Langmuir trough.The pressure-area profiles of meibomian lipid films seeded with SPs (2.5 μL; 0.1 μg) demonstrated hybrid characteristics between meibomian lipid films alone and SPs alone but reached much higher maximum surface pressures (approximately 30 vs. 24 mN/m). Microscopically, the appearance of meibomian lipid films was not altered by SPs. Maximum surface pressure of meibomian films premixed with keratin was much higher than meibum alone. The pressure-area isocycles appeared more like those of meibomian lipids with a low concentration of protein and more like pure keratin films at a high concentration.The data strongly indicate that SPs and keratin likely interact with the TFLL. SPs are likely to act as strong surfactants and to reduce the surface tension of the lipid layer. Excess concentrations of keratin as identified in patients with meibomian gland dysfunction could disrupt the normal structure of the meibomian lipid film.Keywords:
Meibomian gland
Surface pressure
Nonionic surfactant
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Abstract Many of the lung’s mechanical properties are influenced by pulmonary surfactant physicochemical characteristics. Pulmonary surfactant is a complex lipid-protein mixture formed in the type II alveolar cells and secreted into the alveolar subphase [1]. These substances reduce the surface tension at the air-liquid interface of the lining fluid that coats the interior of the lung. At sufficiently high concentrations, pulmonary surfactant reduces the surface tension to near zero and. in the process, stabilizes the alveoli and small airways [2–4].
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Abstract Ionic liquids (ILs) have unique physicochemical properties. ILs with long carbon chains are called surface-active ILs, and they have surfactant properties. In this study, we synthesize (1-butyl-3-methylimidazolium lauroyl sarcosinate) [BMIM] [Lausar] IL that have surfactant properties. Nuclear magnetic resonance spectroscopy (NMR) was used to confirm the chemical structure of the synthesized IL. The surface tension of [BMIM] [Lausar] was determined that it was almost 37.1mN/m. Tween 80 is the most famous commercial surfactant, and we also determine the surface tension of Tween 80. Afterword, we make the binary mixture of Tween 80 and IL-based surfactants. Based on our results, we can conclude that Tween 80 and [BMIM] [Lausar] both reduced surface tension and have excellent surface properties when combining and can be used as surfactants in many sectors.
Carbon chain
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Abstract Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.
Cationic polymerization
Sodium dodecyl sulfate
Nonionic surfactant
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A method for treating both the equilibrium and dynamic surface tension of polydisperse surfactant solutions is introduced and explored. The model is expressed in terms of a pseudo-single-surfactant approximation, where the polydisperse mixture is treated as if it were a pure single-component surfactant. The theory presented is based on the Langmuir adsorption isotherm and suggests that polydisperse surfactants behave as pseudo-single surfactants at equilibrium but diverge from the pseudo-single approach under certain dynamic conditions. Parametric studies provide further insight, suggesting that the dynamic surface tension of polydisperse solutions approaches the pseudo-single-surfactant approximation when competition for interfacial area by surfactant molecules is absent. For systems where competitive adsorption is present, surface tension generally equilibrates more slowly. Finally, the static and dynamic surface tensions of the Tergitol 15-S-n series, an important commercial grade nonionic surfactant, are analyzed in terms of the pseudo-single-surfactant approach. It is observed that the Szyszkowski surface tension equation satisfactorily approximates the equilibrium surface tension for all Tergitols at concentrations below the critical micelle concentration. The pseudo-single-surfactant approach provides a good prediction of dynamic surface tension for the lower Tergitols (15-S-5, 15-S-7, and 15-S-9), but fails to capture the slow equilibration observed in higher Tergitols (15-S-12, 15-S-15, and 15-S-20). This observation is rationalized in terms of the expected lower surface activity of the higher Tergitols.
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The dynamic interfacial tension in surfactant/alkali/acidic oil systems was investigated in a mode of three arylalkyl surfactant flooding. The results indicate that there exists an optimum range of alkali concentrations when the minimum interfacial tension value is below 10−2 mN/m (the ultra-low interfacial tension value) at certain surfactant concentrations. The minimum interfacial tension presents a similar parabolic relationship with alkali concentrations and also a similar hyperbolic relationship with surfactant concentrations as well. Thus, a convexity can be built by the results of three variables, i.e., the minimum interfacial tension, surfactant concentration, and alkali concentration. The capability of synthesized arylalkyl surfactants in reducing the interfacial tension can be expressed by the values of the volumes formed by the three variables. The higher value indicates the stronger capability of the surfactant in reducing the interfacial tension. This method for the capability of surfactant being quantified would offer a new way to choose the surfactants in enhanced oil recovery.
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Sodium dodecyl sulfate
Tension (geology)
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The sections in this article are: 1 Background 1.1 Early Contributors 1.2 Relevance of Alveolar Surface Film 1.3 Current Model of Lung Surfactant Action 2 Definition and Measurement of Surface Tension 2.1 Generation of Interfacial Tension 2.2 Methods 3 Adsorption and Spreading of Surfactant Films 3.1 Form of Surfactant 3.2 Factors Affecting Adsorption and Spreading 4 Properties of Films Related to Lung Surfactant 4.1 Low Surface Tension and Other Quasi-Static Film Properties 4.2 Dynamic Film Properties 5 Influence of Surface Tension on Lung Pressure-Volume Behavior 5.1 Static Properties 5.2 Dynamic Properties 6 Turnover and Recycling of Surfactant Components 6.1 Possible Recycling Paths 6.2 Local Monolayer Recycling 6.3 Extramonolayer Recycling Pathways 7 Summary of Lung Surfactant Properties 7.1 Rapid Adsorption and Spreading 7.2 Low Surface Tension When Film is Compressed 7.3 Stable Low Surface Tension 8 Future Considerations
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Abstract This paper presents the dependence of the surface tension on the surfactant concentration and on the temperature for anionic cetyltrimethylammonium bromide (CTAB) with a concentration of 1 mmol/L and two-ionic lauryl hydroxysultaine (LHS) with a concentration of 2.8 mmol/L. At a low concentration of the surfactant, the surface tension drops sharply at a certain temperature, and at a high concentration it changes slightly, much slower than surface tension of the pure water. Surface tension rapidly drops because micelles in the bulk become unstable and surfactant particles relocate to the interface.
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The influence of different kinds of surfactant on the surface tension of acid solution and the contact angle of rock is different.The relationship between the cleanup efficiency and the surface tension and the contact angle is studied.The surface tension and the contact angle and the cleanup efficiencies of nonionic surfactant,fluorcarbon surfactant and cationic surfactant are measured.The results indicate that and the increase of the contact angle has the same importance as the decrease of the surface tension to the cleanup efficiency of the acid containing surfactant.The quantitative relationship between the cleanup efficiency and the surface tension and the contact angle is presented.The study result of this paper is applied to the development of high-performance cleanup additive,and the optimized experiments show that the cleanup efficiency can reach to 90% when the mass ratio of FX-2 to CTAB to OP-8 is 1∶2∶2 and the concentration of surfactant is 800 mg/L.
Cationic polymerization
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