scholarly journals Surface pressure of liquid interfaces laden with micron-sized particles

Soft Matter ◽  
2020 ◽  
Vol 16 (40) ◽  
pp. 9347-9356
Author(s):  
Rudi Mears ◽  
Iain Muntz ◽  
Job H. J. Thijssen
Keyword(s):  
Surface Pressure ◽  
Theoretical Framework ◽  
Liquid Interfaces ◽  
Langmuir Trough ◽  
Interparticle Interactions

Presenting a theoretical framework to understand the surface pressure of liquid interfaces laden with microparticles, the effect of interparticle interactions on measured surface pressures, and the features of Langmuir-trough surface-pressure graphs.

scholarly journals INTERACTION OF NANOSTRUCTURED LIPID CARRIERS WITH HUMAN MEIBUM

2019 ◽  
pp. 35-42
Author(s):  
Pattravee Niamprem ◽  
Thomas J. Milla ◽  
Burkhardt S. Schuett ◽  
S. P. Srinivas ◽  
Waree Tiyaboonchai
Keyword(s):  
Particle Size ◽  
Surface Pressure ◽  
Tear Film ◽  
Nanostructured Lipid Carriers ◽  
Langmuir Trough ◽  
Surface Activities ◽  
Lipid Films ◽  
Pressure Area ◽  
Surface Active ◽  
High Pressure Homogenizer

Objective: This study aimed to determine the possibility of nanostructured lipid carriers (NLCs) as a bionic tear film by determining the surface activities of the developed NLCs and their interaction with human meibomian lipid films. Methods: NLCs with different types of solid lipids and surfactants were prepared by a high-pressure homogenizer. The particle size was determined by dynamic light scattering. The surface activities of the NLCs and NLCs mixed with meibomian lipids were measured using a Langmuir trough and the resulting surface pressure area (Π-A) profiles were compared. These lipid films were further analyzed using fluorescence microscopy and scanning electron microscopy (SEM). Results: The particle size of prepared NLCs varied from 38–280 nm based on types of solid lipid and surfactant. All NLCs were highly surface active as indicated by their maximum surface pressure (Πmax). The Π-A profiles of meibum seeded with NLCs showed higher surface pressure than meibum alone and the shape of profiles were dominated by the meibomian lipids. These findings were in agreement with fluorescence and SEM micrographs, which revealed that the NLCs could adsorb and integrate to the meibomian lipid films as well as diffuse from the subphase to the lipid films. Conclusion: NLCs are surface active and can integrate with meibomian lipid films formed stable films. The type of interaction can be tailored by altering the solid lipids used in the formulation of the NLCs which could provide the means to develop efficient formulations for targeting dry eye disease related to a non-functional tear film lipid layer.

Synthese und Eigenschaften von Lipoaminosäuren und Lipodipeptiden des Ornithins / Synthesis and Properties of Lipo Amino Acids and Lipodipeptides of Ornithine

1991 ◽  
Vol 46 (8) ◽  
pp. 1098-1104 ◽  
Author(s):  
Gerhard Kellner ◽  
Manfred Liefländer
Keyword(s):  
Amino Acids ◽  
Surface Pressure ◽  
Amino Group ◽  
Carboxylic Group ◽  
Langmuir Trough ◽  
Monomolecular Films ◽  
Pressure Area

Lipo amino acids and α- as well as δ-connected lipodipeptides of ornithine were synthesized. The lipid portion was introduced to the amino group by acylating with hexadecanoyl chloride and to the carboxylic group by amidating with hexadecylamine or octadecylamine, respectively. Due to their amphiphilic properties these compounds were measured in a LANGMUIR-trough and thus their ability to form monomolecular films was examined. Dates from the surface pressure - area isotherms are listed in the following composition.

An automated Langmuir trough for systematic low surface pressure measurements

1990 ◽  
Vol 61 (10) ◽  
pp. 2640-2644 ◽  
Author(s):  
D. Poupinet ◽  
D. Detry ◽  
R. Vilanove ◽  
F. Rondelez
Keyword(s):  
Surface Pressure ◽  
Pressure Measurements ◽  
Langmuir Trough

Surface Pressure Hysteresis of Mixed Lipid/Protein Monolayers: Applications to the Alveolar Dynamics

1984 ◽  
Vol 39 (9-10) ◽  
pp. 965-972 ◽  
Author(s):  
Rada Mutafchieva ◽  
Ivan Panaiotov ◽  
Dimiter S. Dimitrov
Keyword(s):  
Surface Pressure ◽  
Marangoni Effect ◽  
Decisive Role ◽  
Hysteretic Behavior ◽  
Langmuir Trough ◽  
Pressure Surface ◽  
Protein Monolayers ◽  
Alveolar Surfactant ◽  
Alveolar Stability ◽  
Alveolar Surface

Abstract Mixed Lipid/Protein Monolayers, Alveolar Surfactant, Monolayer Models Experimental data on surface pressure-surface area hysteresis of mixed serum albumin/dipal-mitoyl lecithin/sphingomyelin monolayers in the Langmuir trough are presented. Several possible physicochemical mechanisms of the hysteresis are discussed: Marangoni effect, surface pressure relaxations, bulk-to-surface diffusion interchange, and collapse. Depending on the concrete conditions each of these mechanisms can be important. Possible applications of these results to the alveolar dynamics are presented and discussed on the basis of the balloon model of the alveolus. The main conclusions of biological importance are that 1) the alveolar stability depends on the DPL/SM ratio as well as on the protein content. Under normal breathing conditions the surface pressure hysteresis is small and does not play a decisive role in the alveolar dynamics. 2) At large extent of compression the collapse predominates in determining the hysteretic behavior of the alveolar surface.

scholarly journals Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines

2015 ◽  
Vol 6 ◽  
pp. 2154-2160 ◽  
Author(s):  
Simona Bettini ◽  
Emanuela Maglie ◽  
Rosanna Pagano ◽  
Victor Borovkov ◽  
Yoshihisa Inoue ◽  
...  
Keyword(s):  
Surface Pressure ◽  
Aromatic Amines ◽  
Spectral Response ◽  
Pure Water ◽  
Langmuir Trough ◽  
Reflection Spectroscopy ◽  
Conformational Switching ◽  
Porphyrin Derivative ◽  
Clear Cut ◽  
Copper Porphyrin

Cu,H2-bis-porphyrin (Cu,H2-Por2), in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions.

scholarly journals Soft electrostatic repulsion in particle monolayers at liquid interfaces: surface pressure and effect of aggregation

2016 ◽  
Vol 374 (2072) ◽  
pp. 20150130 ◽  
Author(s):  
Peter A. Kralchevsky ◽  
Krassimir D. Danov ◽  
Plamen V. Petkov
Keyword(s):  
Theoretical Model ◽  
Surface Pressure ◽  
Charged Particles ◽  
Interparticle Distance ◽  
Electrostatic Repulsion ◽  
Water Interface ◽  
Liquid Interfaces ◽  
Polar Fluid ◽  
Air Water Interface ◽  
Oil Water

Non-densely packed interfacial monolayers from charged micrometre-sized colloid particles find applications for producing micropatterned surfaces. The soft electrostatic repulsion between the particles in a monolayer on an air/water (or oil/water) interface is mediated by the non-polar fluid, where Debye screening is absent and the distances between the particles are considerably greater than their diameters. Surface pressure versus area isotherms were measured at the air/water interface. The experiments show that asymptotically the surface pressure is inversely proportional to the third power of the interparticle distance. A theoretical model is developed that predicts not only the aforementioned asymptotic law but also the whole surface pressure versus area dependence. An increase in the surface pressure upon aggregation of charged particles in the interfacial monolayers is experimentally established. This effect is explained by the developed theoretical model, which predicts that the surface pressure should linearly increase with the square root of the particle mean aggregation number. The effect of added electrolyte on the aggregation is also investigated. The data lead to the conclusion that ‘limited aggregation’ exists in the monolayers of charged particles. In brief, the stronger electrostatic repulsion between the bigger aggregates leads to a higher barrier to their coalescence that, in turn, prevents any further aggregation, i.e. negative feedback is present. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.

scholarly journals pH- and surface pressure-dependant adsorption of human apolipoprotein A1 at solid/liquid and gas/liquid interfaces

2016 ◽  
Vol 72 (a1) ◽  
pp. s222-s222
Author(s):  
Susanne Dogan ◽  
Michael Paulus ◽  
Paul Salmen ◽  
Yury Forov ◽  
Christopher Weis ◽  
...  
Keyword(s):  
Surface Pressure ◽  
Apolipoprotein A1 ◽  
Liquid Interfaces ◽  
Human Apolipoprotein ◽  
Solid Liquid

Mind wandering as data augmentation: How mental travel supports abstraction

2020 ◽  
Vol 43 ◽  
Author(s):  
Myrthe Faber
Keyword(s):  
Machine Learning ◽  
Data Augmentation ◽  
Mental Content ◽  
Mind Wandering ◽  
Theoretical Framework ◽  
Important Addition

Abstract Gilead et al. state that abstraction supports mental travel, and that mental travel critically relies on abstraction. I propose an important addition to this theoretical framework, namely that mental travel might also support abstraction. Specifically, I argue that spontaneous mental travel (mind wandering), much like data augmentation in machine learning, provides variability in mental content and context necessary for abstraction.

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