Search results for "capsule"

Effect of large positioning holes on capsule fixation of plate-haptic intraocular lenses

2000

Abstract Purpose To compare the centration and fixation of silicone plate-haptic intraocular lenses (IOLs) with different-sized positioning holes. Setting Eye Clinic of the Johannes Gutenberg-University Mainz, Mainz, Germany. Methods In a prospective randomized study, 51 Chiroflex C10 and 56 Chiroflex C11 IOLs were implanted under standardized conditions by the same surgeon. The IOL position was documented at the end of surgery and by retroillumination on the first day and 5 months postoperatively. The positioning-hole area was evaluated by ultrasound biomicroscopy (50 MHz) 5 months postoperatively. Results One day postoperatively, no IOL in either group was decentered more than 1.0 mm. Aft…

Human taeniasis diagnosed by radiography/endoscopy and morphology

2011

Capsule measuring ring to predict capsular bag diameter and follow its course after foldable intraocular lens implantation

2003

Purpose: To evaluate the extent of capsular bag shrinkage after cataract surgery with intraocular lens (IOL) implantation and develop a regression formula to predict postoperative capsular bag size. Setting: Eye Hospital, Johannes Gutenberg-University, Mainz, Germany. Methods: The axial length (AL), anterior chamber depth, and corneal radius in 58 eyes were measured preoperatively. Cataract surgery was by phacoemulsification followed by implantation of a 3-piece, acrylic, posterior chamber IOL. The capsular bag diameter and anterior capsulorhexis were measured intraoperatively and 1 day and 1, 3, and 6 months postoperatively using a Koch capsule measuring ring (HumanOptics). Results: The me…

Effect of a closed foldable equator ring on capsular bag shrinkage in cataract surgery.

2005

To evaluate the effect of a closed foldable equator ring (CFER) versus a conventional capsular tension ring (CTR) on capsular bag shrinkage.Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany.In this prospective study, 70 eyes of 70 patients were randomized to 2 groups using a 1:1 block scheme. After uneventful cataract surgery, a capsular measuring ring was implanted in all eyes to measure the capsular bag diameter in vivo. In Group 1, a CTR was implanted in the capsular bag. In Group 2, a CFER was inserted. Biometric characteristics such as axial length and the horizontal and vertical corneal radii were measured preoperatively. The capsular bag diameter and capsulor…

Mechanical and Structural Tuning of Reversible Hydrogen Bonding in Interlocked Calixarene Nanocapsules

2019

We present force probe molecular dynamics simulations of dimers of interlocked calixarene nanocapsules and study the impact of structural details and solvent properties on the mechanical unfolding pathways. The system consists of two calixarene "cups" that form a catenane structure via interlocked aliphatic loops of tunable length. The dimer shows reversible rebinding, and the kinetics of the system can be understood in terms of a two-state model for shorter loops (≤14 CH2 units) and a three-state model for longer loops (≥15 CH2 units). The various conformational states of the dimer are stabilized by networks of hydrogen bonds, the mechanical susceptibility of which can be altered by changi…

Effect of media composition on long-term in vitro stability of barium alginate and polyacrylic acid multilayer microcapsules.

2000

For a number of applications stability of microcapsules is a critical factor. Since the maintenance of polyelectrolyte complexes depends considerably on the ion composition we tested the physical properties of barium alginate capsules and searched for conditions to improve stability by a multilayer coating with polyethylenimine (PEI) and polyacrylic acid (PAA). Mechanical stability and diameters were determined in barium alginate capsules and compared with multilayer capsules. Multilayer coating resulted in smaller capsules than barium complexing alone. The difference was more pronounced when CaCl2 was used instead of NaCl during coating. Barium alginate capsules and application of CaCl2 du…

Tailoring the stealth properties of biocompatible polysaccharide nanocontainers.

2014

Fundamental development of a biocompatible and degradable nanocarrier platform based on hydroxyethyl starch (HES) is reported. HES is a derivative of starch and possesses both high biocompatibility and improved stability against enzymatic degradation; it is used to prepare nanocapsules via the polyaddition reaction at the interface of water nanodroplets dispersed in an organic miniemulsion. The synthesized hollow nanocapsules can be loaded with hydrophilic guests in its aqueous core, tuned in size, chemically functionalized in various pathways, and show high shelf life stability. The surface of the HES nanocapsules is further functionalized with poly(ethylene glycol) via different chemistri…

Nanocapsules with specific targeting and release properties using miniemulsion polymerization.

2013

The field of application for nanosized materials ranges from mere technical purposes to a growing field of applications in biomedicine. Among the different techniques and processes to produce these materials for encapsulation of reporter molecules and drugs, the miniemulsion process has been proven to be highly adaptable to these specific needs.The review covers the recent developments in the field of miniemulsion as a very powerful technique for the formation of complex carriers for the encapsulation of different kinds of reporter molecule and drugs. The use of a wide variety of polymerization techniques in the miniemulsion process and possible utilization of a wide range of monomers as re…

Magnetic polyorganosiloxane core–shell nanoparticles: Synthesis, characterization and magnetic fractionation

2010

Abstact Here, we present the synthesis, characterization and magnetic separation of magnetic polyorganosiloxane nanoparticles. Magnetic iron oxide nanoparticles with average particle radii of 3.2 nm had been synthesized by a simple coprecipitation process of iron(II) and iron(III) salt in basic solution. Afterwards, the particles were successfully incorporated into a polyorganosiloxane network via a polycondensation reaction of trimethoxymethylsilane (T), diethoxydimethylsilane (D) and the functional monomer (chloromethylphenyl)trimethoxysilane (ClBz-T) in aqueous dispersion. A core–shell system was chosen to increase the flexibility of the system concerning size, composition and functional…

Versatile preparation of silica nanocapsules for biomedical applications

2020

Core–shell nanocapsules are receiving increasing interest for drug delivery applications. Silica nanocapsules have been the focus of intensive studies due to their biocompatibility, versatile silica chemistry, and tunable porosity. However, a versatile one-step preparation of silica nanocapsules with well-defined core–shell structure, tunable size, flexible interior loading, and tailored shell composition, permeability, and surface functionalization for site-specific drug release and therapeutic tracking remains a challenge. Herein, an interfacially confined sol–gel process in miniemulsion for the one-step versatile preparation of functional silica nanocapsules is developed. Uniform nanocap…