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High Frequency Ultrasound (high + frequency_ultrasound)
Selected AbstractsEffect of surfactant type on the synthesis of PMMA using redox initiation and high frequency ultrasoundPOLYMER ENGINEERING & SCIENCE, Issue 10 2008Cristina Parra In the present work, a study of the effect of the surfactant nature on the synthesis of polymethylmethacrylate (PMMA) obtained by high frequency ultrasonic radiation and redox initiation is presented. The surfactants used were an anionic: sodium lauryl sulfate (SLS) and a nonionic: nonylphenol etoxilated. Different morphologies, particle size, and microstructures were obtained depending on the surfactant concentration (0.5, 1.0, 1.5, and 2.0)%. The highest conversion values of PMMA were obtained with SLS, resulting in a highly syndiotactic polymer. High frequency ultrasound is very efficient when ionic surfactants are used. However, for nonionic surfactants ultrasonic irradiation is very inefficient to initiate polymerization, in this case the effect of redox initiation was very marked increasing polymerization conversion. For this, surfactant blends of PMMA/PEO were obtained when redox initiation was used together with high frequency ultrasound. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers. [source] 006 Efficacy of photochemotherapy and UVA-1 therapy in patients with morphea or lichen sclerosusPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 2 2002K. Ghoreschi Morphea and lichen sclerosus are inflammatory skin diseases of unknown aetiology. Morphea can be subdivided into plaque morphea, linear morphea and disabling or generalized morphea. In most patients morphea leads to superficial or deep sclerosis of the skin. The characteristic features of lichen sclerosus which often affects the genital area are edema of upper dermis, inflammatory infiltration and hyalinisation to the dermis at advanced stages. Patients with morphea or lichen sclerosus suffer especially from scar formation and morphea may lead to severe disfigurement, contractures and reduction of quality of life. Skin sclerosis seems to be the result of vascular damage, T cell activation and altered connective tissue production. Various therapies have been reported for lichen sclerosus and morphea. Whereas the topical use of ultrapotent corticosteroids is well established for genital lichen sclerosus, immunosuppressive agents are normally not successful in resolving extragenital skin sclerosis. In a retrospective study we confirmed the efficacy of phototherapy in more than 50 patients with morphea. Fourty treatments with 30 J/cm2 UVA-1 or PUVA-bath photochemotherapy resulted in a significant improvement, reduced skin thickness, as determined by high frequency ultrasound and reconstitution of functional mobility of the skin and even the underlying fasciae. In lichen sclerosus phototherapy was successful only in some patients. Thus for lichen sclerosus the use of topical corticosteroids is the first choice therapy, while phototherapy using either PUVA-bath or medium dose UVA-1 are the most effective treatments for morphea. [source] Effect of surfactant type on the synthesis of PMMA using redox initiation and high frequency ultrasoundPOLYMER ENGINEERING & SCIENCE, Issue 10 2008Cristina Parra In the present work, a study of the effect of the surfactant nature on the synthesis of polymethylmethacrylate (PMMA) obtained by high frequency ultrasonic radiation and redox initiation is presented. The surfactants used were an anionic: sodium lauryl sulfate (SLS) and a nonionic: nonylphenol etoxilated. Different morphologies, particle size, and microstructures were obtained depending on the surfactant concentration (0.5, 1.0, 1.5, and 2.0)%. The highest conversion values of PMMA were obtained with SLS, resulting in a highly syndiotactic polymer. High frequency ultrasound is very efficient when ionic surfactants are used. However, for nonionic surfactants ultrasonic irradiation is very inefficient to initiate polymerization, in this case the effect of redox initiation was very marked increasing polymerization conversion. For this, surfactant blends of PMMA/PEO were obtained when redox initiation was used together with high frequency ultrasound. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers. [source] Noninvasive diagnostic tools for nonmelanoma skin cancerBRITISH JOURNAL OF DERMATOLOGY, Issue 2007M. Ulrich Summary Minimally invasive diagnostic tools have received increased attention for diagnosis, screening and management of nonmelanoma skin cancer (NMSC). Several modalities are commercially available, including high frequency ultrasound, optical coherence tomography and confocal microscopy. While systematic clinical analyses are often lacking, recent reports have shown promising results for reflectance confocal microscopy (RCM) for diagnosis of actinic keratoses and basal cell carcinoma. [source] 2465: Phenotype/genotype evolution in corneal embryologic malformationsACTA OPHTHALMOLOGICA, Issue 2010KK NISCHAL Purpose To describe the evolution of a clinically useful classification of corneal developmental anomalies which has also allowed more accurate phenotype/genotype correlation. Methods The use of clinical documentation using anterior segment photography, normal ultrasound of the eyeball, and high frequency ultrasound and where available histology of host tissue has allowed detailed phenotypes to be developed . Intraoperative recordings of phenotype have also been noted. Genotyping of specific patterns groupings of corneal developmental anomaly phenotypes. Retrospective analysis of clnical outcome with or without surgical intervention. Results Corneal developmental anomalies are best considered in terms of primary corneal disease and secondary corneal disease. The former includes dystophies ( CHED, PPCD and X-L ECD) , corneal dermoids and isolated sclerocornea ( CNA 1 and 2 ).Secondary corneal disease includes secondary to, iridotrabecular anomalies ( eg congenital glaucoma, aniridia, axenfeld -rieger anomaly), kerato-irido-lenticular dysgenesis ( iridolenticular adhesions( Peters type I), failure of lens to form,separate or move away from the cornea). Conclusion Using this classification prognosis for intervention can be shown to be mor successful in primary corneal developmental anomalies. Also by considering groups of patients with similar disease eg primary aphakia, appropriate genotyping can be done eg FOXE3 analysis for children with primary aphakia . More acccurate phenotype allows better clinical classification and ultimately better genotyping of corneal developmental anomalies [source] Recent developments of glaucoma in childrenACTA OPHTHALMOLOGICA, Issue 2009KK NISCHAL Pediatric glaucoma can be a very challenging area of practice. There have been four areas of advances in the last 5-10 years to help improve the outcomes of treatment. Improved pharmacological agents available have been developed for adult glaucoma some of which have been safely used in children , the exception being brimonidine. A better understanding of the dynamics of aqueous flow and how to harness this have led to a safer filtration methodology with the use of antimetabolites especially Mitomycin C. Tubes or setons have been improved in terms of design with valved tubes eg the Ahmed tube , becoming more popular. Lastly, high frequency ultrasound has led to a better understanding and also better delievery of cyclodiode laser ab externo. Endophotocycloablation has also offered increased efficacy of cyloablation. [source] | ||||||||||