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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

LARGE AREA TUNABLE LIQUID CRYSTAL LENS

Jamali, Afsoon, Jamali 15 November 2018 (has links)
No description available.
142

Temporal Examination and Quantification of Fiber Cell Morphology and Arrangement in Chick and Mouse Lenses

Heimlich, Derek 01 October 2020 (has links)
No description available.
143

Impactinvesterares tillämpningar av en genuslins i investering

Ahlin, Martin, Miraglia, Andre January 2023 (has links)
Interviews with impact investors have been conducted to gain a clearer understanding of how socially sustainable investments are made taking into account the identity and gender views of impact investors. The gender lens applied to the study aimed to investigate how gender has been taken into account during company audits and before investment decisions by the impact investors. Furthermore, social identity theory has formed the basis for the deductive study that has been carried out. It has been used to study the impact investors' self-image and how they acted in their professional role in order to gain a deeper understanding of the origin of the impact investors' actions in relation to their identity. These actions have been thematised and examined in terms of criteria, actions, challenges and measures. The recurring factor that most influenced both the company assessment and investment decisions was the dual goals of impact investors, financial return and impact. The clearest contribution the study made was that there is a clearer link between impact investors' self-image and their profession compared to other professionals. How this affects impact investors' actions could not be discerned. Furthermore, the study also found that gender is not taken into account during company audits and investment decisions to the extent that previous research has shown. Risk understanding, potentially increased returns and social sustainability are possible outcomes that gender lens investments contribute to. The study's findings suggest that impact investors were aware of this, yet few of the study's respondents were willing to consider gender when making investment decisions. / Intervjuer med impact-investerare har genomförts för att skapa en tydligare förståelse för hur socialt hållbara investeringar sker med hänsyn till impact-investerarnas identitet och syn på genus. Den genuslins som applicerats på studien avsåg att undersöka hur genus har beaktats under företagsbesiktningar och inför investeringsbeslut av impact-investerarna. Vidare har social identitetsteori legat till grund för den deduktiva studie som gjorts. Den har nyttjats för att studera impact-investerarnas självbild och hur de agerade i sin yrkesroll för att få en djupare förståelse för härkomsten av impact-investerarens aktioner i relation till sin identitet. Dessa aktioner har tematiserats och undersökts utifrån kriterier, handlingar, effekter och åtgärder. Den återkommande faktorn som påverkade både företagsbesiktningen och investeringsbesluten i störst utsträckning var de dubbla målen impact-investerare arbetar mot, finansiell avkastning och impact. Det tydligaste bidraget studien medförde var att det fanns en tydlig koppling mellan impact- investerarnas självbild och förhållandet till deras yrkesgrupp och kultur. Hur det påverkar impact-investerarnas aktioner kunde inte urskiljas. Fortsättningsvis fann studien även att genus inte tas i beaktning under företagsbesiktningar och inför investeringsbeslut i den utsträckning som tidigare forskning visat. Riskförståelse, potentiellt ökad avkastning samt social hållbarhet är möjliga utfall som genuslinsinvesteringar bidrar till. Studiens resultat tyder på att impact-investerarna var medvetna om detta. Trots det var få av studiens respondenter villiga att beakta genus inför investeringsbeslut.
144

Comparison of the Ocular Surface in Adult and Pediatric Contact Lens Wearers

Bickle, Katherine Margaret 18 August 2022 (has links)
No description available.
145

The Longitudinal Analysis of Silicone Hydrogel Contact Lens Study

Szczotka-Flynn, Loretta B. 23 January 2010 (has links)
No description available.
146

Evaporative tear film and contact lens factors associated with dry eye symptoms in contact lens wearers

Nichols, Jason Jay 18 June 2004 (has links)
No description available.
147

Design and Fabrication of convex and concave Lenses made of Transparent Liquids

Saysupan, Sutthilak January 2020 (has links)
This report studies about optical convex and concavelenses, made of liquid materials. Design proposals of the liquidlenses and the required supporting structure (container), as wellas manufacturing method have been investigated. 8 lenses aredesigned: 4 convex and 4 concave. The theoretical expectationsare validated by simulation and experimental results. The methodhave both advantages and disadvantages. The materials in thelenses are water, syrup, benzyl benzoate and bromone naphtha-lene. / Undersökning gällande optiska linser konvexa och konkava, bestående av flytande material. Designförslag av linser och skall, samt tillverkningsmetod har undersökts. De teoretiska förväntningarna validerades genom simulering och experimentella resultat. Metoden visas har både fördelar och nackdelar. Material i de linserna som vi har undersökt är vatten, sockerlösning, bensylbensoat och Bromonaftalen. / Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
148

A Novel Use of Confocal Microscopy to Study Lysozyme Sorption to Silicone Hydrogel and Conventional Hydrogel Contact Lens Materials / Confocal Microscopy to Study Lysozyme Sorption

Zhang, Feng 09 1900 (has links)
The purpose of this study was to observe penetration profiles of lysozyme on a variety of contact lens materials by confocal microscopy, to analyze influential factors that are involved in these penetration curves and to suggest possible mechanisms related to the in-eye clinical performance of these materials. An FITC-lysozyme conjugate was synthesized in-house by amine reaction. Contact lenses were incubated in a lysozyme solution with a final concentration of 1.9 mg/mL for various periods before undergoing microscopic analysis. Optimal parameters for confocal scanning were successfully obtained to acquire desired fluorescence signals on various contact lenses. Measurement units were converted into absolute amounts of lysozyme using lysozyme data from ^(125)I gamma counting studies. A rhodamine labeled dextran solution was applied to distingush the surface of the contact lenses under examination. The data from these studies were then used to calculate the theoretical numbers of layers of adsorbed lysozyme on the lens surface. The results show that there were distinct differences in lysozyme penetration in the twelve hydrogel materials examined. A pure pHEMA lens, with a water content of 38%, deposited lysozyme primarily on the lens surface after 24 hours, with full penetration occurring after 4-weeks of incubation. Three types of non-ionic contact lens materials with water contents > 50% exibited rapid penetration within the lens bulk after 24-hours incubation, with increased deposition within the matrix after 4 weeks. Two ionic, high water content polymers (Acuvue 2 and Focus Monthly) exhibited markedly different penetration profiles, particularly after 24 hours, with very rapid and total penetration in Acuvue 2, as compared with partial penetration in Focus Monthly. Modern silicone hydrogel contact lenses can be nominally divided into first generation, plasma-modified materials and second generation materials which incorporate an internal wetting agent such as polyvinyl pyrrolidone (PVP). These materials exhibited different lysozyme deposition profiles. Lysozyme fully penetrated PureVision after 24 hours, whereas no lysozyme penetration occurred on lenses manufactured from Focus Night & Day or O_2Optix, even after 4 weeks. Lenses manufactured from Acuvue Advance and Acuvue OASYS, two second generation silicone hydrogel lenses, also displayed their own characteristic deposition profile. Acuvue Advance always exhibited a partial penetration of lysozyme within the matrix, even after 4 weeks of doping. Interestingly, Acuvue OASYS showed a similar profile to Focus Night & Day and O_2Optix, with predominantly surface deposition occurring. To confirm possible surface adsorption of lysozyme on surface-coated Focus Night & Day and O_2Optix, a rigid polymethylmethacrylate (PMMA) contact lens was used as a model of surface adsorption. A mounting medium containing rhodamine labeled dextran was scanned to distinguish the lens surface, as it was assumed that no surface penetration of the very high molecular weight dextran would occur. Using this model, it was confirmed that surface adsorption of lysozyme occurred on these plasmacoated lens materials, which is similar to that seen with PMMA. In a further experiment, it was seen that lysozyme sorption on Acuvue OASYS exhibits a penetration profile which is different to that seen in Focus Night & Day and O_2Optix, with lysozyme just penetrating the lens surface. The results from the studies described above demonstrated that in 24 hours lysozyme sorption did not achieve a complete monolayer. However, after 4 weeks multi-layer adsorption occurred, with the more hydrophilic materials depositing the most lysozyme. The quantitative measurement of lysozyme penetration on and into contact lens materials by confocal microscopy combined with ^(125)I labelling offers a valuable tool to discover the potential mechanisms of interactions between protein and polymer materials. This study reveals some important information that may be beneficial to contact lens development and will prove to be valuable in other more broad areas of biomedical research in which polymers and biological fluids come into contact. / Thesis / Master of Applied Science (MASc)
149

Dose Limit Changes to the Lens of the Eye & Its Regulatory Implications

Das, Ryan January 2018 (has links)
The commission on radiological protection through publication 118 decided to recommend a change to the eye dose limit in 2011. ICRP recommendations made in publications, especially ‘publication 60’ and its subsequent update ‘publication 103’ has served as standards for regulatory authorities worldwide in limiting ionizing radiation exposure both to workers and members of the public. For example in Canada, the Canadian Nuclear Safety Commission (CNSC) generally directly adopts recommendations from ICRP. The previous dose limit for the lens of the eye was 150 mSv year-1, based on Publication 60 and 103. Regulatory agencies worldwide have been using this value and subsequently nuclear facilities, hospitals and universities have designed their radiation protection program based on this dose limit for several decades. The new revised eye dose limit now being equivalent to the whole body dose limit will pose significant challenges for sectors where the eye exposure was not characterized as the limit was previously five times over the whole body exposure. A two-step approach was used in conducting this study, firstly a through literature search was conducted on the effects of ionizing radiation to the eye, its radiobiology, fundamentals in established both dose limits was analyzed. Secondly, the authors spent time researching institutions that use ionizing radiation and interviewed engineers, medical physicists, radiation safety officers and regulators from a wide array of fields and industries. Based on the ICRP publications, the review of the literature and the interviews conducted with the nuclear industry, there is consensus in Canada and among IAEA member states that the dose limit for the lens of the eye should be reduced from the original proposed limit of 150 mSv per year. However not to the recommendations suggested by ICRP 118, but, to a standard reasonable and an achievable limit that is 50 mSv per year. / Thesis / Master of Science (MSc) / The International Commission on Radiological Protection (“ICRP”), the independent governing body responsible for radiation protection, since the early 1950s has been issuing recommendations that are widely used as radiological protection standards by regulatory agencies worldwide, primarily UN member states. Since its inception in 1928, the ICRP has served as the basis for radiation protection and value based judgements in protecting both human and non-human biota. In 2011, the commission published (ICRP Pub. 118) its review of epidemiological studies and decided to recommend a change to the previously established eye dose limit. Based on the review of the literature and the research conducted within the academic, veterinary, nuclear and medical industry, there is general consensus in Canada and among IAEA members states that the dose limit for the lens of the eye should be reduced from the original proposed limit, but not to the recommendations suggested by ICRP 118.
150

Měření parametrů optických čoček / Measurement of optical lenses parameters

Wintr, Aleš January 2011 (has links)
This paper contains a basic overview and description of optical lenses. It introduces different types of optical lenses and shows how they influence the passing of light beams. It deals with the production of optical lenses and their practical use. It describes types of optical blemishes that exist in real optical systems. Particular attention is given to parameters of optical lenses and their measurement in practice. It includes a Matlab program to calculate parameters of optical lenses derived from the measurements.

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