Fluoride release from microporous poly(2-hydroxyethyl methacrylate) membranes

Akgol, Sinan/0000-0002-8528-1854; AKGOL, Sinan/0000-0003-2836-7181WOS: 000185837700002Fluoride ion is commonly used in the preventive treatment of tooth decay and when provided with extra fluoride, children living in regions that lack fluoride benefit from it. In the present study, the clinical properties of an intraoral controlled release fluoride delivery system were considered. Poly (2-hydroxyethyl methacrylate) (PHEMA) was examined as a fluoride carrier. Membranes were prepared by photopolymerization and then characterised. Contact angles and swelling ratios of fluoride-loaded membranes were determined. The surface morphology of the membranes were examined by using scanning electron microscopy. In vitro fluoride release studies were carried out in an artificial saliva medium. The concentration of fluoride was measured with a fluoride-specific electrode. The amount of released fluoride was determined and the effects of fluoride loading, medium pH and temperature on fluoride release were investigated. The swelling ratio of the PHEMA membrane was 58.5%, that of the fluoride-loaded PHEMA membrane was 17.8%. Increasing in the fluoride loading amount in the PHEMA membrane accelerated the fluoride release. The fluoride release ratio was increased with increasing pH and temperature. (C) 2003 Elsevier B.V. All rights reserved

Polyhydroxyethylmethacrylate/polyhydroxybutyrate composite membranes for fluoride release

Akgol, Sinan/0000-0002-8528-1854; AKGOL, Sinan/0000-0003-2836-7181WOS: 000179779900012Controlled release technology is a recent technology which has considerable potential in the fields of medicine, pharmacy, and agriculture. Fluoride ion is commonly used in the preventive treatment of decay, and when provided with extra fluoride, children living in regions that lack fluoride benefit from it. For the present study, clinical properties of an intraoral controlled release fluoride delivery system were considered. The preparation of a controlled release membrane system is described. Polyhydroxyethylmethacrylate/polyhydroxybutyrate composite systems were examined as fluoride carriers. Polymeric membranes were prepared by photopolymerization and then character-ized. Contact angles and swelling ratios of fluoride-loaded membranes were determined. The surface morphology of the microporous membranes were examined by using scanning electron microscopy (SEM). In vitro fluoride release studies were carried out in an artificial saliva medium. The amount of released fluoride was determined and the effect of medium pH and temperature on fluoride release was investigated. (C) 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 976-981,2003

Application of local search methods for solving a quadratic assignment problem: A case study

This paper discusses the design and application of local search methods to a real-life application at a steel cord manufacturing plant. The case study involves a layout problem that can be represented as a Quadratic Assignment Problem (QAP). Due to the nature of the manufacturing process, certain machinery need to be allocated in close proximity to each other. This issue is incorporated into the objective function through assigning high penalty costs to the unfavorable allocations. QAP belongs to one of the most difficult class of combinatorial optimization problems, and is not solvable to optimality as the number of facilities increases. We implement the well-known local search methods, 2-opt, 3-opt and tabu search. We compare the solution performances of the methods to the results obtained from the NEOS server, which provides free access to many optimization solvers on the internet