Este trabalho é parte de um projeto destinado a criar um equipamento médico, para ser aplicado com o protocolo de crosslinking de colágeno corneano, para o tratamento do ceratocone, do qual resultou o desenvolvimento de um sistema de irradiação UV-A de córneas para a aplicação clínica oftalmológica. O sistema desenvolvido neste trabalho consiste de um circuito de malha fechada, que estabiliza a potência luminosa emitida (com erro global, após a calibração, menor que 20% durante a emissão), possibilita seu ajuste até 5 mW (6,366 mW/\'CM POT. 2\') e permite selecionar a duração da emissão entre 10 s - 30 min. O sistema irradia com pico em 365 nm \'+ OU -\' 15 nm sendo que o design óptico proporciona spots homogêneos para três diâmetros selecionáveis: 10 mm; 8 mm; e 6 mm. O software desenvolvido tem a função de controlar todo o procedimento médico do crosslinking corneano, além de detectar falhas no sistema. Os resultados obtidos neste trabalho possibilitaram a criação de um equipamento robusto, flexível e estável, capaz de competir diretamente com os produtos internacionais comercializados mundialmente. Até a presente data tem-se conhecimento de apenas dois produtos, para mesma finalidade, comercializados em todo mundo, sendo ambos de empresas européias. Desta maneira, o sistema descrito nesta dissertação integra hoje o único aparelho de crosslinking totalmente projetado e produzido com tecnologia nacional. / This work is part of a project to create a medical device to be applied with the protocol for corneal collagen crosslinking for the treatment of keratoconus, which resulted in the development of an UV-A system for corneas irradiation for ophthalmic clinical application. The developed system consists of a closed loop circuit, which stabilizes the emitted light power (with global error, after calibration, less than 20% over the issue), allows its adjust up to 5 mW (6.366 mW/\'CM POT.2\') and allows to select the emission duration between 10 s - 30 min. The system irradiates with a peak wave length at 365 nm \'+ OU -\' 15 nm and the optical design provides homogeneous spots for three selectable diameter: 10 mm, 8 mm and 6 mm. The developed software has the function of controlling the medical procedure of corneal crosslinking, and detect system failures. The results of this work enabled the creation of a robust equipment, flexible, and stable that can compete directly with international products marketed worldwide. Until the present date, there has been aware of only two products for the same purpose, marketed worldwide, both from European companies. Thus, the system described in this dissertation integrates now the only unit of crosslinking completely designed and produced with national technology.

Este trabalho é parte de um projeto destinado a criar um equipamento médico, para ser aplicado com o protocolo de crosslinking de colágeno corneano, para o tratamento do ceratocone, do qual resultou o desenvolvimento de um sistema de irradiação UV-A de córneas para a aplicação clínica oftalmológica. O sistema desenvolvido neste trabalho consiste de um circuito de malha fechada, que estabiliza a potência luminosa emitida (com erro global, após a calibração, menor que 20% durante a emissão), possibilita seu ajuste até 5 mW (6,366 mW/\'CM POT. 2\') e permite selecionar a duração da emissão entre 10 s - 30 min. O sistema irradia com pico em 365 nm \'+ OU -\' 15 nm sendo que o design óptico proporciona spots homogêneos para três diâmetros selecionáveis: 10 mm; 8 mm; e 6 mm. O software desenvolvido tem a função de controlar todo o procedimento médico do crosslinking corneano, além de detectar falhas no sistema. Os resultados obtidos neste trabalho possibilitaram a criação de um equipamento robusto, flexível e estável, capaz de competir diretamente com os produtos internacionais comercializados mundialmente. Até a presente data tem-se conhecimento de apenas dois produtos, para mesma finalidade, comercializados em todo mundo, sendo ambos de empresas européias. Desta maneira, o sistema descrito nesta dissertação integra hoje o único aparelho de crosslinking totalmente projetado e produzido com tecnologia nacional. / This work is part of a project to create a medical device to be applied with the protocol for corneal collagen crosslinking for the treatment of keratoconus, which resulted in the development of an UV-A system for corneas irradiation for ophthalmic clinical application. The developed system consists of a closed loop circuit, which stabilizes the emitted light power (with global error, after calibration, less than 20% over the issue), allows its adjust up to 5 mW (6.366 mW/\'CM POT.2\') and allows to select the emission duration between 10 s - 30 min. The system irradiates with a peak wave length at 365 nm \'+ OU -\' 15 nm and the optical design provides homogeneous spots for three selectable diameter: 10 mm, 8 mm and 6 mm. The developed software has the function of controlling the medical procedure of corneal crosslinking, and detect system failures. The results of this work enabled the creation of a robust equipment, flexible, and stable that can compete directly with international products marketed worldwide. Until the present date, there has been aware of only two products for the same purpose, marketed worldwide, both from European companies. Thus, the system described in this dissertation integrates now the only unit of crosslinking completely designed and produced with national technology.

No description available.

Dengue virus (DENV) is a mosquito-transmitted flavivirus that threatens approximately half of the world's population. In this dissertation, the use of bioorthogonal chemistry as a tool for researching emerging viral diseases, including DENV is explored. To this end, a bioorthogonally-modified amino acid was successfully installed within the proteome of DENV, which was used for the pull down of a known virus-protein interaction. This technology is intended to be broadly used for the determination of any virus-host interaction, through the installment of a non-perturbing modification that 1) does not hinder viral infectivity and 2) can be selectively discriminated by any complimentary probe. En route to using this technology, a new viral purification strategy was developed for DENV that reduces the overall purification time by 10 hours, and improves retention of virion infectivity. This method and a survey of other viral purification methods used with DENV is contained herein. Furthermore, a chemical scaffold that was repurposed for exploration of protein-protein crosslinking, namely for release of a reactive chemical warhead under acidic conditions, was used for the surface modification of DENV. This triazabutadiene probe was found to be activated by light. In this dissertation is reported the first time aryl diazonium ions for protein crosslinking have been generated on a protein or viral surface through UV-irradiation. The advantages and limitations of this chemistry are presented herein.

Graduation date: 2003

Homogeneous catalysts demonstrate the ability to perform extremely selective organic syntheses with high yields. These catalysts are usually quite expensive and the commercial viability of processes that use homogeneous catalysts depends on the efficiency of catalyst recovery, which is normally quite complex. This obstacle often excludes the use of homogene-ous catalysts from commercial processes. This work investigates the implementation of mem-branes as the unit operation for catalyst recovery as a means to expand the use of homogeneous catalysis. The commercial polyimide, Matrimid, has been examined for its suitability as a membrane material for the homogeneous catalyst recovery of a 1-dodecene hydroformylation reaction, catalyzed by a rhodium-triphenylphosphine transition metal catalyst. This reaction occurs in the liquid phase in solution with toluene. Because of the aggressive environment of the reaction, blends of Matrimid with a crosslinkable, diacetylene-functionalized oligomer have been formed to promote polymer stability through network formation. The diacetylene groups on the oligomer and acetylene end groups can be thermally activated at 250 ??o form distributed polymer networks. Compatible blends of Matrimid and the crosslinking agent can be formed with up to 10% (w/w) crosslinking agent content. Matrimid and the blends have been investigated in the form of dense, nonporous films to evaluate their membrane performance. In terms of material stabilization, it has been found that heat treatment of the neat Matrimid at 250 ??esults in a significant suppression of the material plasticization when exposed to toluene. Addition of the crosslinking oligomer to Matrimid promotes further reduction in swelling and toluene sorption. Transport studies of the reaction components in the materials show that addition of the crosslinking oligomer results in reduced diffusion of the permeating components in the mem-brane materials. However, some increases in solute sorption occur and this is attributed to the oligomer chemistry. A 10% blend of crosslinking agent and Matrimid gave a superior catalyst rejection of 91.5%. The catalyst rejection system has been modeled using Maxwell-Stefan transport equa-tions. Through the model it was found the flux coupling significantly influences the separation characteristics, with sorption of both the solvent and solute as key factors.

No description available.

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-07-19T18:28:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) colacao - cecilia escariao.pdf: 1217403 bytes, checksum: 5bc515a017c6ca8024249a926f827192 (MD5) / Made available in DSpace on 2016-07-19T18:28:21Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) colacao - cecilia escariao.pdf: 1217403 bytes, checksum: 5bc515a017c6ca8024249a926f827192 (MD5) Previous issue date: 2012-09-03 / Objetivo: Avaliar o efeito do crosslinking (CXL) no tratamento de ceratite infecciosa, resistente ao tratamento clínico, e investigar a relação com o agente etiológico. Métodos: Foram incluídos 11 pacientes com diagnóstico de ceratite infecciosa de etiologia bacteriana (sete olhos) e fúngica (quatro olhos) na Fundação Altino Ventura (FAV) no período de outubro de 2011 a maio de 2012. Os pacientes incluídos estavam em uso de colírios há pelo menos sete dias e não apresentavam melhora da infecção. Estes foram avaliados antes da realização do CXL e no período pós-operatório, até cicatrização da úlcera. Para realização do CXL foram instilados gotas de riboflavina a 0,1% e dextrano a 20%, a cada cinco minutos em um período de 30 minutos antes do procedimento, e durante a aplicação da luz ultravioleta A (UVA). A córnea foi exposta a UVA com comprimento de onda de 370m ± 5m e uma irradiância de 3mW/cm². Resultados: Os pacientes com infecção bacteriana obtiveram cura do processo infeccioso após o CXL e nenhum paciente com ceratite fúngica apresentou cicatrização. Observou-se associação significante (p=0,003) entre o agente etiológico e a cicatrização. Conclusão: O CXL mostrou-se eficaz no tratamento de ceratite bacteriana resistente ao tratamento clínico, evitando a realização de transplante tectônico. Em relação a ceratite fúngica, o este procedimento não influenciou para a melhora do processo infeccioso. / Purpose: To evaluate the effect of corneal crosslinking (CXL) in the treatment of infectious keratitis resistant to medical treatment, and investigate the relation with the CXL outcome to the etiologic agent. Methods: The study included 11 patients who were diagnosed with bacterial (seven eyes) or fungal keratitis (four eyes) at Fundação Altino Ventura from October 2011 to May 2012. All patients were using antibiotic eye drops for at least 7 days and have had no infection improvement. Patients were evaluated prior to CXL and the postoperative period until healing of the keratitis. For CXL, eyes were first instilled with a solution containing 0.1% riboflavin and 20% dextran for 30 min at a 5-minutes interval. Riboflavin-soaked eyes were then irradiated with UVA light (370 ± 5m) at 3mW/cm² for 30 minutes. Results: Eyes with bacterial infection exhibited improvement of infectious symptoms after CXL whereas eyes with fungal keratitis showed no improvement. Thus, there was a statistically significant correlation (p = 0.003) between the etiologic agent and the effectiveness of healing. Conclusion: CXL was effective in the treatment of bacterial keratitis resistant to clinical treatment, eliminating the need for surgery. However, CXL was not effective in managing fungal keratitis.

No description available.

There has been widespread interest in corneal biomechanics over recent years, driven largely by the advancements in, and the popularity of refractive surgery techniques and subsequent concerns over their safety. Lately there has been interest into whether crosslinking, which is currently used for the treatment of keratoconus, could be developed as a minimally invasive technique to change the refractive power of the cornea by selectively changing the corneal biomechanics in specific regions to induce a shape change. Successful application of this technique requires a detailed understanding of corneal biomechanics and so far, little is known about the biomechanics of this complex tissue. The current lack of understanding can be mostly attributed to the absence of a suitable measurement technique capable of examining the dynamic behaviour of the cornea under physiological loading conditions. This thesis describes the development of a novel full-field, ex vivo, measurement method incorporating speckle interferometric techniques, to examine the biomechanics of the cornea before and after crosslinking in response to hydrostatic pressure fluctuations representative of those that occur in vivo during the cardiac cycle. The eventual measurement system used for the experiments detailed in this thesis incorporated; an Electronic Speckle Pattern Interferometer (ESPI), a Lateral Shearing Interferometer (LSI) and a fringe projection shape measurement system. The combination of these systems enabled the 3-dimensional components of surface displacement and the 1st derivative of surface displacement to be determined in response to small pressure fluctuations up to 1 mmHg in magnitude. The use of both ESPI and LSI together also enabled the applicability of LSI for measurement of non-flat surfaces to be assessed, and limitations and error sources to be identified throughout this work. To enable the measurement of corneal biomechanics, part of this thesis was concerned with the design of a bespoke loading rig. A chamber was designed that could accommodate tissue of both porcine and human origin. This chamber was linked to a hydraulic loading rig, whereby the cornea could be held at a baseline pressure representative of normal intraocular pressure and small pressure variations could be introduced by the automated vertical movement of the reservoir supplying the chamber. Experiments were conducted on a range of non-biological samples with both flat and curved surface topography, and both uniform and non-uniform mechanical properties, to determine if the measurement configuration was giving the expected measurement data and the loading rig was stable and repeatable. Following experiments on non-biological samples, a range of experiments were conducted on porcine corneas to develop a suitable testing methodology and address some of the challenges associated with corneal measurement, including transparency and hydration instability. During these investigations, a suitable surface coating was identified to generate an adequate return signal from the corneal surface, while not interfering with the response. Alongside this, the natural variation in the response of the cornea was investigated over the total experimental time, and a range of data was presented on corneas before and after crosslinking, which confirmed the suitability of the measurement methods for the assessment of crosslinking. Ultimately, a small sample size of six human corneas were investigated before and after crosslinking in specific topographic locations. From the experiments on human and porcine corneas, full-field maps of surface deformation have been presented, and a compliant region incorporating the peripheral and limbal areas has been identified as being fundamental to the response of the cornea to small pressure fluctuations. In addition to this, the regional effects of crosslinking in four different topographic locations on corneal biomechanics have been evaluated. From this, it has been demonstrated that crosslinking in specific regions in isolation can influence the way the cornea deforms to physiological-scale fluctuations in hydrostatic pressure and this could have implications for refractive correction.