Orientador: Yuzo Iano / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-27T11:30:52Z (GMT). No. of bitstreams: 1 Higa_RogerioSeiji_D.pdf: 315857726 bytes, checksum: fc4b1a8ece5899c3242b8cde47a92645 (MD5) Previous issue date: 2015 / Resumo: Apesar da qualidade das imagens geradas pelas câmeras de segurança ter evoluído, muitas vezes não é suficiente para a identificação do sujeito de interesse. Nem sempre a capacidade do sensor, medida em megapixels, reflete a qualidade da câmera. O conjunto sensor e lente é que define sua real capacidade de captar imagens de qualidade. Eventualmente o foco da câmera não está sobre o objeto de interesse tornando mais difícil sua identificação. Existem, atualmente, as chamadas câmeras plenópticas, que capturam informação 4D da luz sobre a cena e permitem que o foco da imagem seja corrigido. Um software pode ser empregado para o ajuste do foco em regiões de interesse após a captura da imagem. Câmeras de abertura codificada também permitem a recuperação da nitidez da imagem por meio do uso de um padrão na abertura da lente. Essas duas câmeras fazem parte de uma área chamada fotografia computacional, que visa capturar mais informações sobre a distribuição de luz para a posterior visualização. Neste trabalho é proposto o uso de câmeras plenópticas no ambiente de vigilância, e também um novo padrão específico de abertura codificada. Os resultados obtidos revelam a maior eficiência do sistema proposto diante de aberturas apresentadas na literatura / Abstract: Even though the image quality of the surveillance cameras got better, many times the quality is not enough to identify the person of interest. The sensor resolution, measured in megapixels, does not always reflect the quality of the camera. The lens and sensor set defines its real capacity of capturing good images. Eventually the focus of the camera is not on the object of interest, making the identification very difficult. Nowdays there are the so called plenoptic cameras which captures 4D information about the light distribution of the scene. This allows the correction of the image focus. The focus of region of interest can be adjusted through software after the image capture. Coded aperture cameras also allows the sharpness recovery by using a pattern in the lens aperture plane. In this work it is proposed the employment of the plenoptic cameras in surveillance, e also a new specific pattern to coded aperture. The obtained results reveal the better efficiency of the proposed system compared to the ones presented in the literature / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

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Despite the effort to optimize soft contact lens performance, almost half of the 140 million contact lens wearers worldwide experience symptoms of ocular dryness and discomfort, especially towards the end of the day. These symptoms are attributed to reduced compatibility between the contact lens and the ocular surface and are the main reason for contact lens discontinuation. As the interactions of the contact lens-eye interface are dynamic, the surface properties play a key role in improving ocular compatibility, comfort and overall performance of contact lenses. One promising method to reduce adverse interfacial interactions between the contact lens and the ocular surface is to modify the contact lens surface with a biomimetic layer inspired by the ocular surface and the tear film. Hyaluronic acid (HA) is a non-sulfated glycosaminoglycan naturally found in the ocular environment providing ocular hydration and lubrication. Proteoglycan 4 (PRG4), a mucin-like glycoprotein naturally produced at the ocular surface contributes to natural lubrication during blinking and to tear film stability. Surface modification with HA or PRG4 has been shown to result in improved wetting, lubricating and antifouling properties. Moreover, HA and PRG4 have been previously found to interact and synergistically reduce friction further. In the current work, novel HA and PRG4-grafted soft contact lens surfaces were prepared, and the impact of the surface tethered layer on important contact lens properties was assessed. Furthermore, the potential synergistic effect between HA and rhPRG4 on the examined properties was evaluated. Surface immobilization of HA on model conventional (pHEMA) and silicone (pHEMA-co-TRIS) hydrogel contact lenses was achieved by thiol-ene “click” chemistry, while full-length recombinant human PRG4 (rhPRG4) was surface grafted via carbonyldiimidazole (CDI) linking chemistry respectively. The chemical structure after each modification step was determined by attenuated total reflectance FTIR (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS) analyses. HA-grafted model soft contact lenses were characterized by improved surface wettability, antifouling and water retentive properties, while a decreasing trend in boundary friction was observed but only for the HA-grafted pHEMA-co-TRIS materials. Surface-tethering of rhPRG4 was found to effectively enhance the surface wettability and boundary lubricating properties of pHEMA-co-TRIS hydrogels only, whereas both rhPRG4-grafted pHEMA and pHEMA-co-TRIS materials exhibited lower protein sorption and dehydration rate. Overall, the surface immobilization processes followed herein did not alter the optical transparency of the model soft contact lenses or their in vitro compatibility with human corneal epithelial cells. Finally, there was evidence that HA and rhPRG4 synergistically interacted, further improving the contact lens properties. However, the degree of HA/rhPRG4 synergy was found to be dependent on the configuration of the formed HA/rhPRG4 complex as well as the composition of the substrate hydrogel material, with the noted improvement being more significant for the model silicone hydrogels. This is the first study to examine surface grafted full-length rhPRG4 and the effect of this modification on contact lens properties. Moreover, the study is the first to investigate the interactions between covalently tethered rhPRG4 and solutions containing HA. The results of this thesis demonstrate that HA and rhPRG4 are good candidates for the development of novel biomimetic surfaces, especially for silicone hydrogel contact lenses. The potential for using these compounds in synergy was also demonstrated, with wetting solutions of HA showing promise for modifying rhPRG4 modified materials to improve symptoms of discomfort. These naturally occurring ocular agents have the potential to improve the management of ocular dryness and discomfort, thus optimizing the overall soft contact lens performance. / Thesis / Doctor of Philosophy (PhD)

An efficient delivery system and patient compliance are two of the most important factors for any drug delivery system design to be successful. The current standard, particularly to the ocular anterior segment, are topical applications including eye drops. However, due to ocular physical barriers including blinking, the varying tear film layers, and the structure of the corneal epithelium, less that 5% of drug reach the target tissue from a single eye drop dose. While most treatment regiments combat this with increased frequency of dosage and higher than needed concentrations, the need for a more efficient and controlled system has been recognized to reduce the risk of possible side effects. Contact lenses (CL) have been a widely discussed potential drug delivery device given their accepted use in the population, their ability to hold drug, as well as their placement on the ocular surface. The current work focuses on testing a novel delivery system using CLs with the incorporation of drug specific oligonucleotide chains known as aptamers on the surface of the lenses. This application of contact lenses is aimed at capitalizing on the strong affinity of aptamers to hold drug on the surface of the lenses until they are applied to the eyes. The aptamers were covalently attached to the surface via the activation of the hydroxyl groups on pHEMA as a model lens material using 1’1-carbonyldiimidazone CDI chemistry and subsequent reaction with the amine group on the 5' end of the aptamer. The presence of aptamers was confirmed using 6-carbofluorescein (6-FAM) fluorescence detection and x-ray photoelectron spectroscopy (XPS). The release of kanamycin B in comparison to regular pHEMA gels using a soaking uptake method was assessed. In this work, aptamers were confirmed through fluorescence to have been successfully reacted onto the surface, however XPS was not able to confirm a consistent reading. This may have been due to low initial amounts of aptamer or uneven distributions along the surface. The efficiency of the aptamer reaction was not tested and would need to be further investigated. The contact angle had a significant change with increased hydrophilicity at 60.7 ± 1.55° compared to 66.6 ± 0.67°, however physically it should not affect wettability. The lower aptamer amounts resulted in no significant difference during drug release. Kanamycin B was detected using liquid chromatography mass spectroscopy (LCMS) with a reverse phase method using a C18 column however quite a few errors in the methodology led to the conclusion that this method of drug release requires further investigation. It is recommended an aptamer-surface reaction efficiency be determined with the use of a much larger starting aptamer amount, as well as a follow up drug release. / Thesis / Master of Applied Science (MASc)

<p dir="ltr">Though vat photopolymerization-based Additive manufacturing (AM) technology shows potential in fabricating complex optical components rapidly, its poor surface quality and dimensional accuracy render it unqualified for industrial optics applications. The layer steps in the building direction and the pixelated steps on each layer’s contour result in inevitable microscale defects on the 3D-printed surface, far away from the nanoscale roughness required for optics.</p><p dir="ltr">To tackle the lateral stair-stepping issue caused by the pixelated projection pattern, we propose to defocus the curing image pattern by increasing the gap between the light source and the resin vat. This gap intentionally blurs the disconnected pixels to create a continuous and smooth projection pattern. Experiments verified that the smoothened image pattern led to an average 81.2% reduction in surface roughness, which was much more effective than grayscale pixels. The gap between the light source screen and the resin vat also enabled blowing air to dissipate the heat from the resin polymerization, reducing the part distortion and printing failure due to the thermal stress.</p><p dir="ltr">The precision spin coating process is reported to solve vertical stair-stepping defects. We establish a mathematical model to predict and control the spin coating process on 3D-printed surfaces precisely. In this work, a precision aspherical lens is demonstrated with less than 1 nm surface roughness and 1 µm profile accuracy. The 3D-printed convex lens achieves a maximum MTF resolution of 347.7 lp/mm.</p><p dir="ltr">Leveraging this low-cost yet highly robust and repeatable 3D printing process, we showcase the precision fabrication of multi-scale spherical, aspherical, and axicon lenses with sizes ranging from 3 mm to 70 mm using high clear photocuring resins. Additionally, molds were also printed to form multi-scale PDMS-based lenses. Following precision polishing, precision machining, and precision molding, we anticipate that precision spin coating will empower 3D printing as the fourth generation of lens making and unleash the power of 3D-printed lenses in rapid and massive customization of high-quality optical components and systems.</p>

A novel method of fabricating low reflectance mirrors has been developed based on the photosensitivity of hydrogen-loaded, germanium-doped optical fibers. Using a side-writing technique, point-wise refractive index changes have been induced in the core of Ge-doped optical fibers via ultraviolet light from a high power excimer laser. These refractive index changes cause Fresnel reflections at the boundary of the higher photoinduced index change and the lower index in the unexposed core. The boundary of the two refractive indices may be considered a low reflectance mirror. Several techniques have been explored to characterize the Fresnel reflectors including optical time domain reflectometry (OTDR) and spectral analysis. In-line, optical fiber Fresnel reflectors have applications as internal mirrors in intrinsic Fabry-Perot interferometric (IFPI) sensors and OTDR distributed strain sensors. Photoinduced IFPI sensors have performed well as temperature sensors, strain sensors, and vibration sensors. Improved manufacturing techniques are also discussed for future developments. The photoinduced IFPI sensor is inexpensive to manufacture and involves little skill, in contrast to the labor-intensive fabrication techniques of conventional IFPI sensors. The IFPI sensor has commercial applications in embedded structures, high temperature environments, and situations with large EMI conditions. / Master of Science

Yes / Purpose: There are many anecdotal claims that coloured lenses and overlays improve reading performance and there is a substantial literature on the topic of whether reading performance is enhanced through the use of colour. Here we present the results of a systematic review of this literature and examine the quality of the evidence concerning the assertion that reading can benefit from use of coloured overlays or lenses. Methods: We systematically reviewed the literature concerning the effect of coloured lenses or overlays on reading performance by searching the PsychInfo, Medline and Embase databases. Our searches revealed 51 published items (containing 54 data sets). Different systems are in use for issuing coloured overlays or lenses and we reviewed the evidence under four separate system headings (Intuitive, Irlen, Harris/Chromagen and Other). We classified each published item using the Cochrane Risk of Bias tool. Results: Although the different colour systems have been subjected to different amounts of scientific scrutiny, the results do not differ according to the system type, or whether the sample under investigation have been classified as having visual stress (or a similarly defined condition), reading difficulty, or both. The majority of studies are subject to ‘high’ or ‘uncertain’ risk of bias in one or more key aspects of study design or outcome. Studies at lower risk from bias offered less support for the benefit of colour on reading ability. Whilst many studies report improvements with colour, the effect size is generally small and/or similar to the improvement found with a placebo condition. We discuss the strengths and shortcomings of the published literature and, whilst acknowledging the difficulties associated with conducting trials of this type, offer some suggestions about how future trials might be conducted. Conclusions: Consistent with previous reviews and advice from several professional bodies, we conclude that the use of coloured lenses or overlays to ameliorate reading difficulties cannot be endorsed and that any benefits reported by individuals in clinical settings are likely to be the result of placebo, practice or Hawthorne effects.