Dublin City University

About: Dublin City University is a education organization based out in Dublin, Ireland. It is known for research contribution in the topics: Machine translation & Laser. The organization has 5904 authors who have published 17178 publications receiving 389376 citations. The organization is also known as: National Institute for Higher Education, Dublin & DCU.

Plasmonic enhancement of fluorescence for sensor applications

Abstract: In this work we report on the so-called plasmonic enhancement effect, whereby the presence of metallic surfaces or particles in the vicinity of a fluorophore can dramatically alter the fluorescence emission and absorption properties of a fluorophore. The effect, which is associated with the surface plasmon resonance of the metallic surface, depends on parameters such as metal type, particle size, fluorophore type, and fluorophore-particle separation. This work focuses on the creation of metal nanoparticle arrays by a lithographic process and on optimisation strategies to maximise the fluorescence enhancement of dyes in the vicinity of the nanoparticles, for important applications such as fluorescence-based biochip platforms. Ordered arrays of metallic nano-islands were fabricated on glass substrates by a process of natural lithography using monodisperse polystyrene nanospheres. The metal particle dimensions were tailored in order to tune the plasmon resonance wavelength to match the spectral absorption of the fluorophore. The fluorophore, Cy5 dye, which is widely used in optical immunoassays and has a medium quantum efficiency (∼0.3), was used in this preliminary study of the plasmonic enhancement effect. The morphology of the metallic arrays was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Absorption and emission spectroscopies were used to elucidate the enhancement effect and its dependence on metal island morphology. Results were correlated with existing theoretical models. The applicability of this important technique to sensor platforms, such as fluorescence-based biochips, is also discussed.

Teaching in the Age of Covid-19

Abstract: A collection of 84 author's testimonies and workspace photographs between 18 March and 5 May 2020

Green photochemistry: Production of fine chemicals with sunlight*

Abstract: Three photochemical reactions were investigated under solar irradiation conditions with moderately concentrated sunlight: the photoacylation of naphthoquinone with butyraldehyde and the dye-sensitized photooxygenations of citronellol and 1,5-dihydroxynaphthalene, respectively. All reactions were easily performed on multigram-to-kilogram scales using cheap and commercially available starting materials, and yielded important key intermediates for industrial applications.

A point mass in an isotropic universe: existence, uniqueness, and basic properties

Abstract: Criteria which a space-time must satisfy to represent a point mass embedded in an open Robertson-Walker (RW) universe are given. It is shown that McVittie's solution in the case $k=0$ satisfies these criteria, but does not in the case $k=\ensuremath{-}1.$ The existence of a solution for the case $k=\ensuremath{-}1$ is proven and its representation in terms of an elliptic integral is given. The following properties of this and McVittie's $k=0$ solution are studied; uniqueness, the behavior at future null infinity, the recovery of the RW and Schwarzschild limits, the compliance with energy conditions, and the occurrence of singularities. The existence of solutions representing more general spherical objects embedded in a RW universe is also proven.