148 resultados para Plastic Injection Molding
Resumo:
BACKGROUND:
Plantar fasciitis is a common cause of heel pain. The aim of this study was twofold: to compare steroid injection with placebo injection and to compare ultrasound guided with unguided steroid injection in the management of this condition.
METHODS:
65 patients with inferior heel pain were recruited between November 2008 and June 2011. Heel pain was measured using a visual analogue scale (VAS) at baseline and follow-up 6 and 12 weeks after injection.
RESULTS:
22 patients were randomised to ultrasound guided steroid injection, 21 patients to palpation guided steroid injection and 22 to ultrasound guided placebo injection. There was a significant difference in VAS scores between the groups at 6 and 12 weeks (p=0.018 and p=0.004, respectively). There was a 19.7 (95% CI 2.5 to 37.0) difference in mean VAS scores at 6 weeks between the ultrasound guided steroid group and the placebo group and a 24.0 (95% CI 6.6 to 41.3) difference between the unguided steroid group and the placebo group at 6 weeks. At 12 weeks, the mean difference was 25.1 (95% CI 6.5 to 43.6) and 28.4 (95% CI 11.1 to 45.7) respectively between both steroid injection groups and the placebo group. There was no difference in VAS scores following steroid injection between the ultrasound guided and the unguided groups at either time point. Plantar fascia thickness was significantly reduced after injection in both active treatment groups (p=0.00).
CONCLUSIONS:
In this study, steroid injection showed a clear benefit over placebo at 6 weeks and this difference was maintained at 12 weeks.Trial Registration No ISRCTN79628180 (www.controlled-trials.com).
Resumo:
Sustained-release matrix tablets based on Eudragit RL and RS were manufactured by injection moulding. The influence of process temperature; matrix composition; drug load, plasticizer level; and salt form of metoprolol: tartrate (MPT), fumarate (MPF) and succinate (MPS) on ease of processing and drug release were evaluated. Formulations composed of 70/30% Eudragit RL/MPT showed the fastest drug release, substituting part of Eudragit RL by RS resulted in slower drug release, all following first-order release kinetics. Drug load only affected drug release of matrices composed of Eudragit RS: a higher MPT concentration yielded faster release rates. Adding triethyl citrate enhanced the processability, but was detrimental to long-term stability. The process temperature and plasticizer level had no effect on drug release, whereas metoprolol salt form significantly influenced release properties. The moulded tablets had a low porosity and a smooth surface morphology. A plasticizing effect of MPT, MPS and MPF on Eudragit RS and Eudragit RL was observed via DSC and DMA. Solubility parameter assessment, thermal analysis and X-ray diffraction demonstrated the formation of a solid solution immediately after production, in which H-bonds were formed between metoprolol and Eudragit as evidenced by near-infrared spectroscopy. However, high drug loadings of MPS and MPF showed a tendency to recrystallise during storage. The in vivo performance of injection-moulded tablets was strongly dependent upon drug loading. © 2012 American Association of Pharmaceutical Scientists.
Resumo:
It has been shown that mitomycin-C increases the success rate of trabeculectomy; however, a rise in the incidence of postoperative complications has also been reported. Consequently, the use of antimetabolite is usually reserved for patients who are at high risk of surgical failure or for patients with advanced glaucoma in whom low intraocular pressure is desired. This report describes a patient who suffered severe visual loss which was a direct result of hypotonous maculopathy after trabeculectomy with mitomycin-C and various other complications from the subsequent interventions.
Resumo:
Simulations of the injection stretch-blow moulding process have been developed for the manufacture of poly(ethylene terephthalate) bottles using the commercial finite element package ABAQUS/standard. Initially a simulation of the manufacture of a 330 mL bottle was developed with three different material models (hyperelastic, creep, and a non-linear viscoelastic model (Buckley model)) to ascertain their suitability for modelling poly(ethylene terephthalate). The Buckley model was found to give results for the sidewall thickness that matched best with those measured from bottles off the production line. Following the investigation of the material models, the Buckley model was chosen to conduct a three-dimensional simulation of the manufacture of a 2 L bottle. It was found that the model was also capable of predicting the wall thickness distribution accurately for this bottle. In the development of the three-dimensional simulation a novel approach, which uses an axisymmetric model until the material reaches the petaloid base, was developed. This resulted in substantial savings in computing time. © 2000 IoM Communication Ltd.
Resumo:
Ferroelectric domain wall injection has been demonstrated by engineering of the
local electric field, using focused ion beam milled defects in thin single crystal lamellae of KTiOPO4 (KTP). The electric field distribution (top) displays localized field hot-spots, which correlate with nucleation events (bottom). Designed local field variations can also dictate subsequent domain wall mobility, demonstrating a new paradigm in ferroelectric domain wall control.
Resumo:
Plastic wastes, and particularly plastic bags and sachets, are a major concern for urban and rural environment in African countries. In the last years some actions have been started for the plastic recycling like the artisanal production of paving blocks with melted plastic bags and sand, albeit with differences in production processes. Nevertheless, the environmental and economic impact of such activities is still to be confirmed. The aim of this study is to propose a methodology for assessing and comparing the environmental and energetic performances of artisanal methods, and for defining the overall quality of the produced blocks. This methodology has been shaped through the analysis of
production processes operated by artisans/small enterprises in West Africa and through physic-mechanical tests on the blocks. A questionnaire which allows an insight into the process and on the product has been developed and tested over five processes. Results show that a high input energy level is observed through all the processes, while considerable savings of energy could be achieved. Moreover, tests results confirmed the importance of the utilised plastic concerning thermal dilatation, mechanical resistance at higher temperature and cooling-shrinkage effects. In conclusion, doubts remain about the technical and environmental effectiveness of the sampled experiences, durability of the products and sustainability of this approach. Nevertheless, being the collection and recycling of plastic wastes a potential income generation activity for marginalised social groups in urban environment, a process optimisation could improve the impact of blocks production. Alternative recycling activities should also be considered.