3 resultados para Maximum contrast analysis

em Aston University Research Archive


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Our object was to describe the process of coping in King-Kopetzky syndrome and hypothesise how the process is mediated. We used a qualitative study using open-ended interviews. The data were gathered purposefully from 19 cases in the first phase of the study. Accounts were then compared deductively with six accounts from a previous interview-based study. Maximum contrast was sought in cases and in experience of clinical interventions. Participants were recruited from Hearing Therapy services in Bath and North East Somerset Primary Care Trust and The Welsh Hearing Institute. Interviews were conducted in participants’ homes or clinic setting. Coping was determined by the concept that the individual developed about their hearing difficulties. The process of conceptualizing involves reconciling the symptoms experienced with the information obtained from clinicians. The process is mediated by the context in which hearing difficulties occur and the interventions that are received. Forming a coherent concept of hearing difficulties facilitates coping. Clinicians can assist this process by giving patients with King-Kopetzky Syndrome an explanation of the condition.

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Liposomes due to their biphasic characteristic and diversity in design, composition and construction, offer a dynamic and adaptable technology for enhancing drug solubility. Starting with equimolar egg-phosphatidylcholine (PC)/cholesterol liposomes, the influence of the liposomal composition and surface charge on the incorporation and retention of a model poorly water soluble drug, ibuprofen was investigated. Both the incorporation and the release of ibuprofen were influenced by the lipid composition of the multi-lamellar vesicles (MLV) with inclusion of the long alkyl chain lipid (dilignoceroyl phosphatidylcholine (C 24PC)) resulting in enhanced ibuprofen incorporation efficiency and retention. The cholesterol content of the liposome bilayer was also shown to influence ibuprofen incorporation with maximum ibuprofen incorporation efficiency achieved when 4 μmol of cholesterol was present in the MLV formulation. Addition of anionic lipid dicetylphosphate (DCP) reduced ibuprofen drug loading presumably due to electrostatic repulsive forces between the carboxyl group of ibuprofen and the anionic head-group of DCP. In contrast, the addition of 2 μmol of the cationic lipid stearylamine (SA) to the liposome formulation (PC:Chol - 16 μmol:4 μmol) increased ibuprofen incorporation efficiency by approximately 8%. However further increases of the SA content to 4 μmol and above reduced incorporation by almost 50% compared to liposome formulations excluding the cationic lipid. Environmental scanning electron microscopy (ESEM) was used to dynamically follow the changes in liposome morphology during dehydration to provide an alternative assay of liposome stability. ESEM analysis clearly demonstrated that ibuprofen incorporation improved the stability of PC:Chol liposomes as evidenced by an increased resistance to coalescence during dehydration. These finding suggest a positive interaction between amphiphilic ibuprofen molecules and the bilayer structure of the liposome. © 2004 Elsevier B.V. All rights reserved.