In this thesis, the potential of Chemical Exchange Saturation Transfer to image brain metabolites is presented. The Bloch-McConnell equations are simulated and the optimal parameters are found to...Show moreIn this thesis, the potential of Chemical Exchange Saturation Transfer to image brain metabolites is presented. The Bloch-McConnell equations are simulated and the optimal parameters are found to be 3.5uT, tsat = 1s for glutamate and 3uT, tsat = 1.5s for creatine. Furthermore, multiple quantification methods, including MTR asymmetry, Lorentzian fits and spinlock fits are evaluated for quantifying CEST signal from glutamate and creatine. The quantification methods are tested on the Bloch-McConnell simulations, 2-pool phantoms, 3-pool phantoms and in vivo.Show less
In this thesis, we investigate the mechanical interplay between a cell’s shape and its actin cytoskeleton organisation. We combine theoretical work with numerical simulations and experimental data...Show moreIn this thesis, we investigate the mechanical interplay between a cell’s shape and its actin cytoskeleton organisation. We combine theoretical work with numerical simulations and experimental data to investigate this behaviour. The actin cytoskeleton is modelled using a liquid crystal framework and is combined with a model for the cell contour that has stress fibers apply a directed stress on the edge. We describe a feedback mechanism where the orientation of stress fibers is a competition between alignment with the cell edge and with one another, and where the shape of the cell edge is dependent on the contractile force exerted along the direction of the nearby stress fibers. We show that we can accurately reproduce the shape and anisotropic actin cytoskeleton structure of cells on micropillar arrays, as well as the emergence of topological defects.Show less
This thesis is concerned with the design of numerical methods for solving the Schrödinger equation for a system of two-electrons in a double quantum dot. Theoretical background is presented for the...Show moreThis thesis is concerned with the design of numerical methods for solving the Schrödinger equation for a system of two-electrons in a double quantum dot. Theoretical background is presented for the physics of a two-electron quantum dot. Implementation of the double dot system is via the QuTiP library is discussed and a numerical approach for the treatment of the system using the density matrix formalism is presentedShow less
High-fidelity single photon sources are required for quantum information technologies and fundamental research. Recently near-unity single photon purity and near-unity indistinguishability have...Show moreHigh-fidelity single photon sources are required for quantum information technologies and fundamental research. Recently near-unity single photon purity and near-unity indistinguishability have been shown in resonantly pumped quantum dots embedded in an optical cavity. In this thesis we provide a theoretical framework and experimental results on polarization non-degenerate self-assembled InAs/GaAs quantum dots inside a polarization non-degenerate cavity, and show that by filtering the polarization the brightness of the single photon source can be enhanced. We furthermore describe the resulting output light analytically as a mixture of single photons and coherent light and derive a simple expression for the purity of the single photon source. Lastly we present pulsed measurements of this quantum dot-cavity system, and show that the purity of the single photon source is 98%.Show less
Metamaterials exhibit exotic properties derived from their geometric structures. A procedure has recently been developed to build reconfigurable structures from convex polyhedra. While initally...Show moreMetamaterials exhibit exotic properties derived from their geometric structures. A procedure has recently been developed to build reconfigurable structures from convex polyhedra. While initally characterized as rigid, we found that some of these structures possess multiple stable configurations. In the present study we develop numerical tools to simulate all possible deformations that can be applied to these structures, mapping the corresponding energy landscape. We use the simulation to identify the additional stable configurations and study their dependence on key physical parameters. Based on the results found, we explain the mechanism behind the observed multistability and suggest its validity as fundamental ingredient for a general designing rule. Finally, we explore the possibility of implementing our results into the development of a reconfigurable, multistable and multifunctional 3D material.Show less
