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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

When a biomaterial is inserted into the body, the interaction of the surface with the surrounding biological environment is crucial. Given the importance of the surface, the ability to alter the surface properties to support a compatible environment is therefore desirable. Silicone hydrogel contact lenses (CL) allow for improved oxygen permeability through the incorporation of siloxane functional groups. These groups however are extremely surface active and upon rotation, can impart hydrophobicity to the lens surface, decreasing lens wettability and increasing protein and lipid deposition. Lens biofouling may be problematic and therefore surface modification of these materials to increase compatibility is exceedingly recognized for importance in both industry and research. The current work focuses on the creation of a novel anti-fouling polymer surface by the incorporation of 2-methacryoyloxyethyl phosphorylcholine (MPC), well known for its biomimetic and anti-fouling properties. A controlled polymerization method was used to generate a unique double-grafted architecture to explore the effect of increasing surface density of polyMPC chains on corresponding anti-fouling properties. The novel free polymer was synthesized by a 3-step atom transfer radical polymerization (ATRP). First, poly(2-hydroxyethyl methacrylate) (polyHEMA) was polymerized by ATRP, where the hydroxyl (OH) groups of the polymer then underwent an esterification to create macroinitiating sites. From these sites, a second ATRP of poly(MPC) varying in length occurred, yielding the double-grafted polymer poly(2(2-bromoisobutyryloxy-ethyl methacrylate)-graft-poly(2-methacryloyloxyethyl phosphorylcholine (pBIBEM-g-pMPC). The polymer was designed for resistance to protein adsorption through a possible synergistic effect between the surface induced hydration layer by surrounding PC groups coupled with steric repulsion of the densely grafted chains. To test its potential as a surface modifier, the polymer was grafted from model silicone hydrogel CL through a 4-step surface initiated ATRP (SI-ATRP) in a similar manner to the free polymer. First, the ATRP initiator was immobilized from the HEMA OH groups of the unmodified CL, generating Intermedate-1. A polyHEMA brush was grafted from the initiating sites yielding pHEMA-50, followed by the generation of a second initiator layer (Intermediate- 2). A sequential ATRP of poly(MPC) then generated the target pMPC-50/pMPC-100 surfaces. For the free pBIBEM-g-pMPC polymer analysis, 1H-NMR and GPC determined polymers formed with a predictable MW and low polydispersity (PDI). For surface grafting, using a sacrificial initiator, 1H-NMR and GPC indicated that the pHEMA-50 and pMPC-50/pMPC-100 polymers were well-controlled, with a MW close to the theoretical and a low PDI. For surface chemical composition, ATR-FTIR showed the presence of the ATRP initiator (Intermediate-1 and 2) by the appearance of a C-Br peak and disappearance of the OH peak. XPS confirmed the chemical composition of the 4-step synthesis by a change in the fraction of expected surface elements. Both the surface wettability and EWC of the materials increased upon pMPC modification, further improving upon increasing pMPC chain length. The contact angle was as low as 16.04 ± 2.37º for pMPC-50 surfaces and complete wetting for pMPC-100. Finally, the single protein adsorption using lysozyme and bovine serum albumin (BSA) showed significantly decreased protein levels for pMPC-50/100 lenses, as much as 83% (p 0.00036) for lysozyme and 73% (p 0.0076) for BSA, with no significant difference upon chain length variation. The aforementioned data demonstrates that the novel polymer has potential in providing an anti-fouling and extremely wettable surface, specifically regarding silicone hydrogel CL surfaces. / Thesis / Master of Applied Science (MASc)

This research examined two issues. First, it tested whether accurate map position-finding could be performed in a photographically simulated environment. Test subjects were asked to locate map position sites represented by color 35mm slides encompassing a 360-degree panoramic view for the corresponding ground location. Second, it tested if the perspective imparted by the lens type used to photograph the panoramic views had a significant effect on the accuracy of location selection by the subjects. The two lenses tested were a 50mm (normal perspective) lens and a 28mm (moderately wide-angle) lens which distorted distance, but provided a wider field-of-view. Results indicated that: 1) subjects were able to locate a specific map position by viewing color slides; 2) map position-finding accuracy performance was more dependent on the site itself than on the 35mm slide presentation; and, 3) there appeared to be no significant difference in map position-finding accuracy performance between using views photographed with a 50mm lens and a 28mm lens. / M.S.

No / Following aberroscopy, aspheric front surface soft contact lenses (SCLs) were custom-made to correct spherical refractive error and ocular spherical aberration (SA) of 18 myopic and five hypermetropic subjects (age, 20.5 . 5 yr). On-eye residual aberrations, logMAR visual acuity, and contrast sensitivity were compared with the best-correcting spectacle lens, an equally powered standard SCL, and an SCL designed to be aberration free in air. Custom-made and spherical SCLs reduced SA ( p . 0.001; p . 0.05) but did not change total root-meansquare (rms) wave-front aberration (WFA). Aberration-free SCLs increased SA ( p . 0.05), coma ( p . 0.05), and total rms WFA. Visual acuity remained unchanged with any of the SCL types compared with the spectacle lens correction. Contrast sensitivity at 6 cycles/degree improved with the custom-made SCLs ( p . 0.05). Increased coma with aspheric lens designs and uncorrected astigmatism limit the small possible visual benefit from correcting ocular SA with SCLs.

Yes / We thank Professors Evans and Wilkins for their interest in our systematic review.(1) We have reached the same conclusion as previous systematic reviews published in 2008(2) and 2014(3) and a review prepared for the New Zealand Ministry for Health in 2009.(4) Even the ‘alternative systematic review’ prepared by Professors Evans and Allen about which we have significant misgivings concludes that ‘larger and rigorous randomised controlled trials of interventions for visual stress are required’.(5) / A response to Professors Evans and Wilkins regarding the systematic review: Griffiths PG, Taylor RH, Henderson LM and Barrett BT (2016) The effect of coloured overlays and lenses on reading: a systematic review of the literature. Ophthalmic & Physiological Optics. 36: 519–544.

Time is gaining recognition as an important research perspective, yet the assumptions, concepts, and boundaries of this perspective vary greatly across different fields. This diversity suggests that time offers both significant depth and relevance as a lens for research. However, the diversity of approaches also harbors ambiguity and a lack of coherence, hindering scholars’ ability to integrate insights and harness the full potential of time as a research lens. To address this issue, we review the diverse time-based assumptions, domains, and concepts in extant research. Our review reveals three dominant manifestations of the temporal lens: time as resource, time as structure, and time as process. We analyze and synthesize insights of the three lenses to offer an integrative framework to support future research. The framework informs and reveals opportunities for time-based research by foregrounding connections and contrasts among the lenses. Building on this framework, we discuss two principal pathways for future research: connecting the three lenses through the study of tensions at their interfaces, and enhancing the three lenses through the study of more complex conceptions of time.

Tesis por compendio / [ES] La necesidad de confinar y manipular micro-objetos tiene aplicaciones en múltiples áreas de la ciencia y tecnología. Actualmente, existen diversas técnicas para lograr este objetivo, y una de las más destacadas es el uso de las llamadas pinzas ópticas, que se han convertido en una herramienta ampliamente utilizada en laboratorios de todo el mundo. Este trabajo de investigación se centra en el fascinante campo del atrapamiento y manipulación de micro-objetos, con un enfoque destacado en la combinación de elementos ópticos difractivos y la técnica de pinzas ópticas. Esta combinación permite un aumento de la versatilidad de los sistemas experimentales de pinzas ópticas. Los avances presentados en esta tesis tienen aplicaciones en una amplia gama de campos, desde la nanotecnología hasta la biología celular. Como lentes difractivas implementadas en los sistemas de pinzas ópticas, se introducen las lentes difractivas Kinoform basadas en la secuencia aperiódica m-Bonacci. Estas lentes permiten atrapar múltiples partículas simultáneamente y manipularlas tridimensionalmente en dos planos focales diferentes, lo que amplía significativamente las posibilidades de investigación y desarrollo en diversas disciplinas. Además, se aborda la generación de múltiples trampas ópticas mediante lentes Kinoform cuadrifocales basadas en otra secuencia aperiódica conocida como Silver Mean, permitiendo atrapar partículas en cuatro planos focales de manera simultánea. Este avance mejora significativamente la versatilidad de los sistemas de pinzas ópticas. Adicionalmente el uso de vórtices multiplexados en un sistema de pinzas ópticas, permite atrapar de manera independiente múltiples partículas y transferir momento angular. Estos avances abren nuevas posibilidades en la construcción de micromotores y aplicaciones de micro-ensamblaje. Un efecto asociado a las trampas ópticas es la generación de microburbujas, en la actualidad estas se han convertido en objeto de estudio debido a la facilidad de generación y a sus posibles aplicaciones como agentes de transporte de partículas o micro-objetos. Aprovechando este efecto en esta tesis se implementa una técnica de atrapamiento que emplea fuerzas termoforéticas en la captura y manipulación de microburbujas en líquidos. Esto constituye otro avance importante en el campo del atrapamiento tridimensional. Por último, se desarrolla un laboratorio virtual utilizando COMSOL Multiphysics para simular el atrapamiento acústico, lo que permite a los estudiantes interactuar con el sistema y comprender mejor este fenómeno. Este enfoque educativo proporciona herramientas valiosas para la comprensión y análisis de la manipulación de partículas, lo que beneficia a los estudiantes de pre-grado y grado interesados en este campo. En conjunto, todos estos avances representan contribuciones significativas en el campo del atrapamiento y manipulación de partículas, en particular a través de las pinzas ópticas, promoviendo el progreso tecnológico y científico en diversas disciplinas y brindando oportunidades educativas para futuras generaciones de investigadores y científicos. A lo largo del desarrollo de esta tesis, se han creado nuevos elementos difractivos que superan ciertas limitaciones y aumentan las capacidades de las pinzas ópticas, abriendo nuevas perspectivas de aplicación para tecnologías preexistentes. / [CA] La necessitat de confinar i manipular microobjectes té aplicacions a múltiples àrees de la ciència i la tecnologia. En l'actualitat, hi ha diverses tècniques per assolir aquest objectiu, i una de les més destacades és l'ús de les anomenades pinces òptiques, que han esdevingut una eina molt utilitzada en laboratoris de tot el món. Aquest treball de recerca se centra en el fascinant camp de la captura i la manipulació de microobjectes, destacant la combinació d'elements òptics difractius i la tècnica de les pinces òptiques. Aquesta combinació permet augmentar la versatilitat dels sistemes experimentals de pinces òptiques. Els avenços presentats en aquesta Tesi tenen aplicacions en una àmplia gamma de camps, des de la nanotecnologia a la biologia cel·lular. Com a lents difractives implementades en sistemes de pinces òptiques, es presenten les lents difractives Kinoform basades en la seqüència aperiòdica m-Bonacci. Aquestes lents permeten atrapar simultàniament múltiples partícules i manipular-les tridimensionalment en dos plans focals diferents, fet que amplia significativament les possibilitats de recerca i desenvolupament en diverses disciplines. A més, s'aborda la generació de múltiples trampes òptiques utilitzant lents Kinoform quadrifocals basades en una altra seqüència aperiòdica coneguda com a Silver Mean, que permet atrapar partícules en quatre plans focals simultàniament. Aquest avenç millora significativament la versatilitat dels sistemes de pinces òptiques. A més, l'ús de vòrtexs multiplexats en un sistema de pinces òptiques permet atrapar múltiples partícules de manera independent i transferir el moment angular. Aquests avenços obren noves possibilitats en la construcció de micromotors i aplicacions de microassemblatge. Un efecte associat a les trampes òptiques és la generació de microbombolles, actualment aquestes s'han convertit en objecte d'estudi a causa de la facilitat de generació i de les seves potencials aplicacions com a agents de transport de partícules o microobjectes. Aprofitant aquest efecte, aquesta Tesi implementa una tècnica d'atrapament que utilitza forces termoforètiques en la captura i manipulació de microbombolles en líquids. Això constitueix un altre avenç important en el camp de l'atrapament tridimensional. Finalment, es desenvolupa un laboratori virtual utilitzant COMSOL Multiphysics per simular l'atrapament acústic, cosa que permet als estudiants interactuar amb el sistema i comprendre millor aquest fenomen. Aquest enfocament educatiu proporciona eines valuoses per a la comprensió i l'anàlisi de la manipulació de partícules, cosa que beneficia els estudiants de grau i postgrau interessats en aquest camp. En conjunt, tots aquests avenços representen contribucions significatives al camp de l'atrapament i la manipulació de partícules, particularment a través de pinces òptiques, promovent el progrés tecnològic i científic en diverses disciplines i proporcionant oportunitats educatives per a futures generacions d'investigadors i científics. Al llarg del desenvolupament d'aquesta Tesi, s'han creat elements difractius nous que superen certes limitacions i augmenten les capacitats de les pinces òptiques, obrint noves perspectives d'aplicació per a tecnologies preexistents. / [EN] The need to confine and manipulate micro-objects has applications in multiple areas of science and technology. Currently, there are several techniques to achieve this goal, and one of the most prominent is the use of the so-called optical tweezers, which have become a widely used tool in laboratories around the world. This research work focuses on the fascinating field of micro-object capture and manipulation, highlighting the combination of diffractive optical elements and the optical tweezers technique. This combination allows to increase the versatility of the experimental optical tweezers systems. The advances presented in this thesis have applications in a wide range of fields, from nanotechnology to cell biology. As diffractive lenses implemented in optical tweezers systems, Kinoform diffractive lenses based on the aperiodic m-Bonacci sequence are presented. These lenses allow multiple particles to be trapped simultaneously and manipulated three-dimensionally in two different focal planes, which significantly expands the possibilities for research and development in various disciplines. In addition, the generation of multiple optical traps is addressed using quadrifocal Kinoform lenses based on another aperiodic sequence known as Silver Mean, which allows particles to be trapped in four focal planes simultaneously. This advance significantly improves the versatility of optical tweezer systems. In addition, the use of multiplexed vortices in an optical tweezer system allows multiple particles to be trapped independently and angular momentum to be transferred. These advances open up new possibilities in micromotor construction and microassembly applications. One effect associated with optical traps is the generation of microbubbles, currently these have become an object of study due to the ease of generation and their potential applications as transport agents for particles or micro-objects. Taking advantage of this effect, this thesis implements an trapping technique that employs thermophoretic forces in the capture and manipulation of microbubbles in liquids. This constitutes another important advance in the field of three-dimensional trapping. Finally, a virtual laboratory is developed using COMSOL Multiphysics to simulate acoustic trapping, allowing students to interact with the system and better understand this phenomenon. This educational approach provides valuable tools for the understanding and analysis of particle manipulation, benefiting undergraduate and graduate students interested in this field. Taken together, all of these advances represent significant contributions to the field of particle trapping and manipulation, particularly through optical tweezers, promoting technological and scientific progress in various disciplines and providing educational opportunities for future generations of researchers and scientists. Throughout the development of this thesis, new diffractive elements have been created that overcome certain limitations and increase the capabilities of optical tweezers, opening new application perspectives for pre-existing technologies. / We acknowledge the financial support from Ministerio de Ciencia e Innovación (grants PID2019-107391RB-I00 and PID2022-1142407NB-I00), Generalitat Valenciana (grant PROMETEO/2019/048 and CI-PROM/2022/30), and Universitat Politècnica de València (PAID-01-20-25), Spain. We acknowledge the financial support from CONACyT (grant A1-S-28440). / Muñoz Pérez, FM. (2024). Diseño y caracterización experimental de sistemas de atrapamiento y manipulación de micro-objetos mediante técnicas ópticas, térmicas y acústicas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203436 / Compendio

Yes / A recent randomised controlled trial indicated that providing long-term multifocal wearers with a pair of distance single-vision spectacles for use outside the home reduced falls risk in active older people. However, it also found that participants disliked continually switching between using two pairs of glasses and adherence to the intervention was poor. In this study we determined whether intermediate addition multifocals (which could be worn most of the time inside and outside the home and thus avoid continual switching) could provide similar gait safety on stairs to distance single vision spectacles whilst also providing adequate ‘short-term’ reading and near vision. Methods: Fourteen healthy long-term multifocal wearers completed stair ascent and descent trials over a 3-step staircase wearing intermediate and full addition bifocals and progression-addition lenses (PALs) and single-vision distance spectacles. Gait safety/caution was assessed using foot clearance measurements (toe on ascent, heel on descent) over the step edges and ascent and descent duration. Binocular near visual acuity, critical print size and reading speed were measured using Bailey-Lovie near charts and MNRead charts at 40 cm. Results: Gait safety/caution measures were worse with full addition bifocals and PALs compared to intermediate bifocals and PALs. The intermediate PALs provided similar gait ascent/descent measures to those with distance single- vision spectacles. The intermediate addition PALs also provided good reading ability: Near word acuity and MNRead critical print size were better with the intermediate addition PALs than with the single-vision lenses (p < 0.0001), with a mean near visual acuity of 0.24 0.13 logMAR (~N5.5) which is satisfactory for most near vision tasks when performed for a short period of time. Conclusions: The better ability to ‘spot read’ with the intermediate addition PALs compared to single-vision spectacles suggests that elderly individuals might better comply with the use of intermediate addition PALs outside the home. A lack of difference in gait parameters for the intermediate addition PALs compared to distance single-vision spectacles suggests they could be usefully used to help prevent falls in older well-adapted full addition PAL wearers. A randomised controlled trial to investigate the usefulness of intermediate multifocals in preventing falls seems warranted.