Search results for "Silicone oil"
showing 8 items of 18 documents
Effect of head position on refraction in aphakic and phakic silicone-filled eyes.
1997
BACKGROUND The refraction of the eye is altered significantly after the instillation of silicone oil into the vitreous cavity because of the silicone oil's high refractive index. The degree of the refractive change shows diurnal variation and depends on the patient's head position. PATIENTS AND METHODS To analyze the degree and time course of refractive changes with respect to head position, the authors performed objective refraction in five aphakic and five phakic silicone oil-instilled eyes with attached maculae using an automatic hand-held refractometer. In each patient, 25 measurements were taken at short intervals using a hand-held autorefractometer with the patient in different positi…
Experimental and Theoretical Study of the Field Induced Phase Separation in Electro- and Magnetorheological Suspensions
1999
We present here the study of field induced phase separation in E.R. and M.R. fluids. Two thermodynamic models — one for the formation of chais of particles and the other for phase separation are presented and compared with experimental results obtained with two kinds of suspensions. One was made of silica particles in silicone oil and the other was made of magnetic polystyrene particles in water. In the presence of a flow the phase separation occurs with the dense phase forming a regular pattern of stripes. The dependence of the period of these stripes on the intensity of the magnetic field is well reproduced by the same kind of thermodynamic model if we add the effect of normal stresses i…
Adhesives and mounting media in aerobiological sampling
1989
Abstract Because microscopical identification and counting is vital in most aerobiological studies, pollen and spores are usually collected on some adhesive. The adhesives should not be water-soluble. For optically best results water-soluble mounting media with refractive indices about 1.40–1.45 are used. There are compatibility problems between water insoluble adhesives and watery mounting media. The former tend to move to stripes or droplets, distorting the image and moving the spores from their original positions. To solve this problem several adhesives based on silicone oils, silicone greases and vaseline or their mixtures were tested. The usual watery mounting media, glycerine gelatine…
Towards micrometer sized core-shell actuators from liquid crystalline elastomers by a continuous flow synthesis
2012
We present here the successful preparation of liquid crystalline core-shell elastomers via a microfluidic double-emulsion process. The customized set-up allows for a temperature-controlled fabrication of the core-shell particles from a thermoresponsive mesogenic monomer. The nematic liquid crystalline shell is filled with a non-mesogenic core of silicone oil. To verify the core-shell structure with optical microscopy, we prepared particles with a colored core using a red dye. We were also able to micro-manipulate the particles and penetrate them with a small glass capillary to extract the liquid core.
Postoperative Komplikationen nach Silikonölinstillation
1997
Die Verwendung von Silikonol beinhaltet verschiedene Komplikationen, die den Erfolg des vitreoretinalen Eingriffes oftmals reduzieren. In einer retrospektiven Studie analysierten wir den Krankheitsverlauf von insgesamt 511 Augen (503 Patienten) mit komplizierter NH-Amotio verschiedener Genese, bei denen eine Pars-plana-Vitrektomie mit Silikonoltamponade durchgefuhrt worden war, um Komplikationen nach Silikonoltamponade festzustellen. Bei den untersuchten Augen handelte es sich um 267 komplizierte PVR-Amotiones, 126 diabetische Traktionsamotiones, 74 Amotiones nach perforierender Bulbusverletzung, 27 Amotiones mit Riesenris und 17 Augen mit verschiedenen anderen Netzhauterkrankungen wie Endo…
The Use of Silicones as Extractants of Biologically Active Substances from Vegetable Raw Materials
2021
Based on theoretical studies, the authors of this paper propose the use of cosmetic organosilicon polymers (commonly called silicones) for the extraction of a complex of biologically active substances contained in vegetable raw materials. It is important to note that the biological molecules do not interact with the organosilicones and, therefore, their properties are not altered after the extraction. In this work, we investigate the efficiency of several polyorganosiloxanes as extractants of vegetable raw materials (Calendula Officialis L. and Artemisia Absinthium L.) useful for the preparation of cosmetic emulsions. Specifically, the extraction studies were conducted by using polyorganosi…
Preparation of actuating fibres of oriented main-chain liquid crystalline elastomers by a wetspinning process
2011
We present a versatile method to prepare oriented fibres with a defined thickness from main-chain liquid crystalline elastomers. A microfluidic setup is utilized to inject a solution of a photocrosslinkable smectic A main-chain polymer into a co-flowing stream of silicone oil. Diffusion of the solvent into the oil yields solid polymer filaments that are crosslinked in a continuous way by UV-irradiation. The obtained fibres are highly oriented and show a reversible and significant contraction during the liquid crystal's phase transition.
Optical quality of hyperopic and myopic phakic intraocular lenses
2013
Aims: To assess and compare the optical quality of the myopic and hyperopic implantable collamer lens (ICL) from its wavefront aberrations for different powers and pupil diameters. Settings and Design: Prospective study. Material and Methods: The wavefront aberrations of two myopic (−3 and −6 diopters (D)) and two hyperopic V4b ICLs (+3 and +6D) were measured in vitro . To assess and compare the optical quality of different powers of ICLs, we analyzed the root mean square (RMS) of total higher order aberrations (HOAs), trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration at 3- and 4.5-mm pupil. In addition, the point spread functions (PSFs) of each ICL evaluated were ca…