Search results for "Silicone Elastomers"
showing 10 items of 10 documents
Oxygen Transmissibility of Piggyback Systems With Conventional Soft and Silicone Hydrogel Contact Lenses
2006
To investigate the apparent oxygen transmissibility of various piggyback systems using conventional and silicone hydrogel soft contact lenses of different water content and permeability, rigid poly(methyl methacrylate), and rigid gas-permeable lenses of medium, high, and ultrahigh oxygen permeability. The aim of the study was to establish which material (rigid or hydrogel) is more representative of the resulting oxygen performance of piggyback systems. METHODS: The apparent oxygen transmissibility of 66 piggyback systems was measured with an electrochemical method. Eighteen of these combinations involved the use of silicone hydrogel contact lenses currently available. One hyperpermeable rig…
Silicone-Silver Penile Prosthesis: Description, Operative Approach and Results
1980
A silicone penile prosthesis in which silver wires are embedded to allow for voluntary bending of the penis for urination and resting position and for straightening for intercourse is described. The implantation is done via a hemicircular incision on the dorsum of the penis in the sulcus coronarius. Buck's fascia is identified and opened, and the corpora are dilated up to 30F. After the exact length is determined with a special sizer the prosthesis is slipped into each corpus cavernosum. The advantage of this approach is the optimal insertion of the prosthesis distal to the sulcus coronarius, thereby preventing kinking of the glans during intercourse. Our experiences with the implantation i…
Transrenal Ureteral Occlusion with a Detachable Balloon
1982
Transrenal ureteral occlusion using a detachable balloon was successfully employed to stop urinary flow in seven patients. The balloon was filled with low-viscosity silicone rubber and released in the distal ureter. Percutaneous nephrostomy provided external drainage. Indications were painful dysuria and large urinary fistulas in advanced pelvic malignancy. The method is preferable to ureteral embolization with tissue adhesive.
Comparison of the Ultraviolet Light Filtering across Different Intraocular Lenses.
2018
SIGNIFICANCE We have analyzed the ultraviolet transmittance of some commercial intraocular lenses (IOLs). The results show differences of wavelength cutoff among them. PURPOSE The purpose of this study was to measure and compare the ultraviolet light transmittance of different IOLs made out of acrylic hydrophobic, hydrophilic, and hydrophilic with hydrophobic surface materials from different manufacturers. METHODS The spectral transmission curves of eight monofocal IOLs with the same dioptric power of +20.0 diopters were measured using a PerkinElmer Lambda 35 ultraviolet/visible spectrometer. Two IOLs of each type were tested three times. The ultraviolet cutoff wavelength at 10% transmissio…
Resistance to disinfection of a polymicrobial association contaminating the surface of elastomeric dental impressions.
2009
The aim of this study was to evaluate the ability to resist disinfection of a polymicrobial association contaminating the surface of dental impressions obtained with two different elastomers: a polyether (Impregum) and an addition-polymerized silicone (Elite). Impressions were contaminated with a mixture of three biofilm-forming microorganisms (Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans) and disinfected immediately after contamination, or after microbial layers were allowed to develop during a six-hour storage. Two commercial disinfectants were tested: MD 520 containing 0.5% glutaraldehyde and Sterigum Powder without glutaraldehyde. Residual contamination was recover…
A free plate model can predict guided modes propagating in tubular bone-mimicking phantoms
2014
The goal of this work was to show that a non-absorbing free plate model can predict with a reasonable accuracy guided modes measured in bone-mimicking phantoms that have circular cross-section. Experiments were carried out on uncoated and coated phantoms using a clinical axial transmission setup. Adjustment of the plate model to the experimental data yielded estimates for the waveguide characteristics (thickness, bulk wave velocities). Fair agreement was achieved over a frequency range of 0.4 to 1.6 MHz. A lower accuracy observed for the thinnest bone-mimicking phantoms was caused by limitations in the wave number measurements rather than by the model itself.
Absorption of oxybutynin from vaginal inserts: drug blood levels and the response of the rabbit bladder.
2000
Abstract Objectives. Oxybutynin has been used for treatment of urge urinary incontinence for more than 20 years. However, one of the major problems with its use is uncomfortable anticholinergic side effects that can lead to discontinuation of treatment. Alternative forms of drug administration may reduce side effects and thus improve patient compliance. Methods. A cylinder-shaped, curved silicone elastomer insert containing oxybutynin was anchored in the vagina of female rabbits. The inserts were designed to release oxybutynin at rates of 0.5, 1.0, and 5.0 mg/day, respectively. Blood drug and metabolite levels were monitored for 1 to 7 days and cystometry was carried out after 7 days of tre…
Physicochemical Surface Properties of Various Intraocular Lenses
2001
<i>Purpose:</i> It is of major interest to understand how intraocular lens (IOL) surfaces interact with aqueous humor or tissues after implantation. Important parameters to describe the physicochemical surface properties are the contact angle and critical surface tension. Therefore, we performed measurements of the contact angle and critical surface tension of several commercially available IOLs. <i>Setting:</i> Department of Ophthalmology, Johannes Gutenberg University, Mainz, University Eye Hospital, Tübingen, and Max Planck Institute for Polymer Research, Mainz, Germany. <i>Methods:</i> A total of 17 commercially available standard quality IOL types (6…
Changes in higher-order aberrations after implantation of a foldable iris-claw lens in myopic phakic eyes
2006
Purpose To evaluate the change in higher-order aberrations (HOAs) after implantation of a foldable iris-claw phakic intraocular lens (pIOL) in myopic eyes. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods This prospective nonrandomized comparative self-controlled trial included 41 eyes that had implantation of a foldable iris-claw pIOL between July 2003 and November 2004. All patient data for HOAs (Zernike coefficient) were measured and calculated using the same pupil size preoperatively and postoperatively, and the root-mean-square (RMS) wavefront error was calculated. Examinations were performed preoperatively as well as 1 week and 3, 6, and 12 m…
The effect of immersion disinfection procedures on dimensional stability of two elastomeric impression materials
2008
The aim of this study was to determine the effect of immersion disinfection procedures on the dimensional stability of two elastomeric impression materials. Impressions of a stainless steel die were made with polyether (PE) and with additionpolymerized silicone rubber (PVS). The test specimens underwent disinfection treatment by immersion in two commercially available solutions containing quaternary ammonium compounds (Sterigum Powder, SP) and glutaraldehyde plus an amino derivative (MD520, MD), respectively. The impressions were measured at 4 different time points: before any disinfection treatment (T0); after the first disinfection (T1); 6 hours after the first disinfection (T2); after th…