scholarly journals The effect of serum proteins on dynamic interfacial properties of silicone oils in vitrectomized eyes

2018 ◽  
Vol 2 (2) ◽  
pp. 52-57
Author(s):  
Irene Nepita ◽  
Libero Liggieri ◽  
Eva Santini ◽  
Francesca Ravera ◽  
Mario R. Romano ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Aqueous Humor ◽  
Serum Proteins ◽  
Silicone Oil ◽  
Interfacial Properties ◽  
Quantitative Information ◽  
Silicone Oils ◽  
Natural Surfactants ◽  
Viscoelastic Modulus

The formation and stability of emulsions in vitrectomized eyes is linked to the properties of the silicone oil-aqueous humor interface, in particular the surface tension. In the presence of natural surfactants, such as serum and plasma, the value of the surface tension is likely to change, but little quantitative information is presently available.To this end, we perform accurate experiments measuring the interfacialproperties of the Siluron 1000 (Fluoron GmbH, Ulm, Germany) silicone oil with an aqueous solution in the presence of endogenous-like proteins. It is found that the surface tension is significantly reduced when physiologically realistic concentrations are used. Moreover, the values obtained for the dilational viscoelastic modulus are compatible with the formation of stable emulsions.

scholarly journals The Role of Endogenous Proteins on the Emulsification of Silicone Oils Used in Vitreoretinal Surgery

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Irene Nepita ◽  
Rodolfo Repetto ◽  
Jan O. Pralits ◽  
Mario R. Romano ◽  
Francesca Ravera ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Serum Proteins ◽  
Vitreous Body ◽  
Vitreoretinal Surgery ◽  
It Value ◽  
Silicone Oils ◽  
Dilational Viscoelasticity ◽  
Endogenous Proteins ◽  
The Stability

The present work is aimed at investigating the chemicophysical properties of the interface between silicone oils (SOs) used in vitreoretinal surgery and aqueous solutions, in the presence of surfactant biomolecules. Such molecules are thought to play an important role in the formation of SO emulsions in vitrectomised eyes, in which the natural vitreous body has been replaced with a SO. In particular, we have measured the interfacial tension (IT) and the interfacial dilational viscoelasticity (DV) of the interface between SO (Siluron 1000) and serum proteins (albumin and γ-globulins) at various concentrations in a Dulbecco alkaline buffer. The equilibrium IT value is relevant for the onset of emulsification, and the DV influences the stability of an emulsion, once formed. The study is complemented by preliminary emulsification tests. The experimental results show that, when proteins are dissolved in the aqueous solution, the rheological properties of the interface change. The IT decreases significantly for physiological protein concentrations, and the DV modulus achieves high values, even for small protein concentrations. The emulsification tests confirm that, in the presence of proteins, emulsions are stable on the time scale of months. We conclude that the measured values of IT in the presence of serum proteins are compatible with the promotion of droplet formation, which, in addition, are expected to be stable against coalescence. Adsorption of biomolecules at the interface with the SO is, therefore, likely to play an important role in the generation of an emulsion in eyes subjected to vitrectomy. These findings are relevant to identify strategies to avoid or control the formation of emulsions in eyes.

scholarly journals Accelerated recombination of lophyl radicals and control of the surface tension with amphiphilic lophine dimers

2019 ◽  
Vol 55 (66) ◽  
pp. 9769-9772
Author(s):  
Masaaki Akamatsu ◽  
Kazuki Kobayashi ◽  
Kenichi Sakai ◽  
Hideki Sakai
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Interfacial Properties ◽  
Rapid Control ◽  
And Control

The accelerated photoisomerization of amphiphilic lophine dimers enabled rapid control of the interfacial properties of aqueous solution with photoirradiation.

scholarly journals Succinic acid in aqueous solution: connecting microscopic surface composition and macroscopic surface tension

2014 ◽  
Vol 16 (39) ◽  
pp. 21486-21495 ◽  
Author(s):  
Josephina Werner ◽  
Jan Julin ◽  
Maryam Dalirian ◽  
Nønne L. Prisle ◽  
Gunnar Öhrwall ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Succinic Acid ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Md Simulations ◽  
Vapor Interface ◽  
X Ray ◽  
Ph Values ◽  
Microscopic Surface

The water–vapor interface of aqueous solutions of succinic acid, where pH values and bulk concentrations were varied, has been studied using surface sensitive X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations.

Acoustic and elastic properties of silicone oil under high pressure

RSC Advances ◽  
2015 ◽  
Vol 5 (48) ◽  
pp. 38056-38060 ◽  
Author(s):  
Xiaoxia Wang ◽  
Chen Chen ◽  
Xiaoli Huang ◽  
Jiayu Wang ◽  
Mingguang Yao ◽  
...  
Keyword(s):  
High Pressure ◽  
Elastic Properties ◽  
Silicone Oil ◽  
Brillouin Scattering ◽  
Silicone Oils ◽  
Scattering Spectra

Brillouin scattering spectra of three silicone oils with different viscosity, including two polydimethylsiloxanes (PDMS) and one polyphenylmethylsiloxane (PPMS), have been studied under high pressure.

Silicone Oils and their Properties used in Rhegmatogenous Retinal Detachment Surgery

2019 ◽  
pp. 176-180
Keyword(s):  
Retinal Detachment ◽  
Rhegmatogenous Retinal Detachment ◽  
Silicone Oil ◽  
Chemical Properties ◽  
Retinal Tear ◽  
Giant Retinal Tear ◽  
Silicone Oils ◽  
Medical Indications ◽  
Physical And Chemical ◽  
And Chemical Properties

Silicone oils are polymer structures including siloxane repeats in the center. Copolymers formed by combining these polymers at different ratios constitute different silicone structures with different physical and chemical properties. The presence of several factors such as trauma, giant retinal tear, proliferative vitreoretinopathy and retinal tear in posterior localization is the main medical indications for the use of silicone oils in the surgery of rhegmatogenous retinal detachment. Problems associated with the need for a second surgical intervention to remove silicone oil, the emulsification of silicone oil with the problem this emulsification, and the presence of foreign structure in eye globe are the most important conditions limiting the use of silicone oil.

Natural-Convection Heat Transfer in Liquids Confined by Two Horizontal Plates and Heated From Below

1959 ◽  
Vol 81 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Samuel Globe ◽  
David Dropkin
Keyword(s):  
Heat Transfer ◽  
Silicone Oil ◽  
Convection Heat Transfer ◽  
Test Results ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Silicone Oils ◽  
Prandtl Numbers ◽  
The Relationship ◽  
Rayleigh Numbers

This paper presents results of an experimental investigation of convective heat transfer in liquids placed between two horizontal plates and heated from below. The liquids used were water, silicone oils of 1.5, 50, and 1000 centistoke kinematic viscosities, and mercury. The experiments covered a range of Rayleigh numbers between 1.51(10)5 and 6.76(10)8. and Prandtl numbers between 0.02 and 8750. Tests were made in cylindrical containers having copper tops and bottoms and insulating walls. For water and silicone oils the container was 5 in. in diam and 2 in. high. For mercury, two containers were used, both 5.28 in. in diameter, but one 1.39 in. high and another 2.62 in. high. In all cases the bottom plates were heated by electric heaters. The top plates were air-cooled for the water and silicone-oil experiments and water-cooled for the mercury tests. To prevent amalgamation, the copper plates of the mercury container were chromium plated. Surface temperatures were measured by thermocouples embedded in the plates. The test results indicate that the heat-transfer coefficients for all liquids investigated may be determined from the relationship Nu=0.069Ra13Pr0.074 In this equation the Nusselt and Rayleigh numbers are based on the distance between the copper plates. The results of this experiment are in reasonable agreement with the data reported by others who used larger containers and different fluids.

Surface Tension of Aqueous Humor

2010 ◽  
Vol 19 (7) ◽  
pp. 456-459 ◽  
Author(s):  
Andrew Ross ◽  
Robert C. Blake ◽  
Ramesh S. Ayyala
Keyword(s):  
Surface Tension ◽  
Aqueous Humor
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