Predicting and verifying the tunable optical properties of metal nanostructures is central to designing materials optimized for specific applications. Chemically- deposited nanostructures have been well-studied near the percolation threshold, but at lower surface coverages they exhibit sample-to-sample variations in the optical response. We identify how these variations are driven by the high variability in the particle size distribution in a particular surface coverage range. We then explore film- coupled nanoparticle systems consisting of a silver nanoparticle, thin dielectric spacer layer, and flat silver film, to enable tuning toward the blue and green parts of the spectrum. We use the boundary element method to visualize charge distributions of various resonances. We fabricate samples using thermal evaporation and spin coating methods, and use polarized reflectance spectroscopy to measure their optical response at an ensemble level. We achieve a 532nm resonance for 80nm silver nanoparticles on 13nm PMMA spacers and 100nm silver thin films. The resulting design is a candidate for enhancing fluorescence in a new spectral range. This dissertation includes previously unpublished co-authored material.

Consideramos uma teoria escalar acoplada não minimamente à gravitação no contexto de alguns modelos inflacionários. Mostramos como esse acoplamento inviabiliza a inflação caótica. Analisamos em seguida um modelo proposto por Linde para contornar esses problemas. Mostramos que sua realização é trivial. / We consider a scalar theory non minimally coupled to gravitation in the context of some inflationary models. We show how this coupling prevents the chaotic inflation. Then analyzed a model proposed by Linde to avoid these problems. We show that its realization is trivial.

Neste trabalho apresentamos condições suficientes para a obtenção de taxas exponenciais de convergência na lei multidimensional dos grandes números para campos aleatórios definidos em R^Z_d. Dentre possíveis aplicações do resultado apresentamos medidas não-gibbsianas e não-FKG (limites de saturaçãoo de processos de estacionamento) e medidas estacionárias originárias de sistemas de partículas (rede com perdas, incluindo o caso onde há interação de longo alcance com cauda pesada). / We describe sufficient conditions for the occurrence of exponential rates of convergence in the multidimensional law of large numbers for random fields in RZd . Non-gibbsian and non-FKG measures from statistical mechanics (jamming limits of RSA models) and IPS (stationary measures of loss networks, including heavy-tail long-range interaction) are indicated as examples where the result applies.

Tsang Hing Wa = 梯度粒子系統的扭轉運動 / 曾慶華. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 66-68). / Text in English; abstracts in English and Chinese. / Tsang Hing Wa = Ti du li zi xi tong de niu zhuan yun dong / Zeng Qinghua. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Localization --- p.1 / Chapter 1.1.1 --- Localization by Potential Confinement --- p.1 / Chapter 1.1.2 --- Localization by Interference --- p.2 / Chapter 1.2 --- Graded Materials --- p.2 / Chapter 1.3 --- Rotational Motion --- p.3 / Chapter 2 --- Torsional Motion of Rotating Particles with Graded Couplings / Chapter 2.1 --- Linear Couplings --- p.5 / Chapter 2.1.1 --- Model and Formalism --- p.5 / Chapter 2.1.2 --- Gradient in Coupling Constant --- p.7 / Chapter 2.1.3 --- Gradient in Moment of Inertia --- p.8 / Chapter 2.1.4 --- Numerical Results --- p.9 / Chapter 2.1.5 --- Discussion and Conclusion --- p.14 / Chapter 2.2 --- Non-Linear Couplings --- p.14 / Chapter 2.2.1 --- Model and Formalism --- p.14 / Chapter 2.2.2 --- Gradient in Coupling Constant --- p.16 / Chapter 2.2.3 --- Gradient in Moment of Inertia --- p.16 / Chapter 2.2.4 --- Numerical Results --- p.17 / Chapter 2.2.5 --- Discussion and Conclusion --- p.29 / Chapter 3 --- Torsional Motion of Rotating Particles with graded potential --- p.30 / Chapter 3.1 --- Linear Interaction --- p.30 / Chapter 3.1.1 --- Model and Formalism --- p.30 / Chapter 3.1.2 --- Gradient in On-site Torsional Potential --- p.32 / Chapter 3.1.3 --- Numerical Results --- p.33 / Chapter 3.1.4 --- Discussion and Conclusion --- p.43 / Chapter 3.2 --- Non-linear Interaction --- p.43 / Chapter 3.2.1 --- Model and Formalism --- p.43 / Chapter 3.2.2 --- Numerical Results --- p.45 / Chapter 3.2.3 --- Chaotic Effect --- p.62 / Chapter 3.2.4 --- Discussion and Conclusion --- p.64 / Chapter 4 --- Conclusion --- p.65 / Bibliography --- p.66

La qualité de l’air est un enjeu environnemental majeur de notre société. Cette thèse se focalise sur l’observation depuis l’espace du polluant gazeux majeur, l’ozone troposphérique. Les instruments satellitaires de nouvelle génération permettent de le mesurer journalièrement aux échelles régionales à globale. Cependant, les mesures d’un seul domaine spectral n’amène pas d’information suffisante pour quantifier les concentrations de l’ozone dans la couche limite atmosphérique, où se situe l’air que nous respirons. Le couplage des mesures de multiples domaines spectraux offre un fort potentiel pour mieux caractériser la pollution à l’ozone. La première approche multispectrale à 2 bandes combinant les mesures de l’infrarouge (IR) de IASI et l’ultraviolet (UV) de GOME-2 a été développée au laboratoire LISA, que j’ai intégré dans le cadre de ma thèse. L’objectif de mon travail de thèse est de franchir un pas supplémentaire dans la quantification de la pollution à l’ozone en incluant la bande visible (VIS) de Chappuis, afin de développer un couplage multispectral inédit à trois bandes spectrales UV+VIS+IR. Premièrement, j’ai mis au point une approche pour extraire l’information sur l’ozone des spectres VIS de GOME-2, en sélectionnant les longueurs d’onde affectées majoritairement par l’absorption à l’ozone et rejetant celles avec des absorptions d’autres gaz, ainsi que déterminant les variables d’ajustement conjoint de l’approche (profil vertical d’ozone, albédo de surface, shifts spectraux, etc) et les bases de données nécessaires pour simuler les spectres VIS (albédo de surface, spectroscopie).Ensuite, j’ai mis en œuvre la méthode multispectrale à trois bandes UV+VIS+IR, premièrement sur des observations simulées défilantes de IASI et GOME-2 et géostationnaires de MAGEAQ afin d’estimer l’amélioration en terme de sensibilité et précision, par rapport aux méthodes existantes. Dernièrement, j’ai appliqué l’approche multispectrale à 3 bandes à des observations satellitaires réelles de IASI et GOME-2. Des comparaisons avec d’autres données montrent des meilleures performances des nouvelles observations UV+VIS+IR pour caractériser des évènements de pollution à l’ozone, par rapport à l’approche à 2 bandes / Air quality is a major environmental issue for our society. This PhD thesis focuses on space borne observation of the major gaseous pollutant. Tropospheric ozone. New generation satellite instruments allow measuring it daily at regional to global scales. However, single spectral domain measurements do not provide enough information for quantifying ozone concentrations at the atmospheric boundary layer, where the air we breathe is located. Synergism of measurements from multiple spectral domains offers a great potential for better characterizing ozone pollution. The first 2-band multispectral approach combining infrared (IR) measurements of IASI and the ultraviolet (UV) of GOME-2 was developed at LISA laboratory, where I conducted my thesis. The goal of my thesis is to go a step further in the quantification of ozone pollution by including the visible (VIS) Chappuis band, in order to develop an unprecedented 3-band multispectral synergism UV+VIS+IR. First, I developed a approach for extracting ozone information from GOME-2 VIS spectra, by selecting the wavelengths mostly affected by ozone absorption and rejecting those with absorptions from other gases, as well as determining the joint adjustment variables of the approach (vertical ozone profile, surface albedo, spectral shifts, etc) and the databases needed to simulate the spectra VIS (surface albedo, spectroscopy).Then, I implemented the multispectral method with three bands UV+VIS+IR, first on simulated low-orbit and geostationary observations from respectively IASI and GOME-2 and MAGEAQ to estimate the improvement in terms of sensitivity and precision, as compared to existing methods. Last, I applied the 3-band multispectral approach to real satellite observations of IASI and GOME-2. Comparisons with other data shows enhanced performances of the new UV+VIS+IR observations to characterize ozone pollution events, with respect to the 2-band approach

Mutação na proteína <font face = \"symbol\">b-glucuronidase Klotho tem sido associada com envelhecimento prematuro e disfunção cognitiva. Embora altamente expressa em regiões específicas do encéfalo, as funções da proteína Klotho no sistema nervoso central ainda são desconhecidas. Aqui, mostramos que animais com gene mutado e hipomórfico para a proteína Klotho possuem regulação glicêmica alterada, sugerindo maior sensibilidade à insulina. No sistema nervoso central, vias relacionadas à sinalização intracelular de insulina apresentam-se mais ativadas no hipocampo, com maior ativação de AKT e mTOR e inativação dos fatores de transcrição FOXO. Neurônios hipocampais em cultura parecem responder à estimulação por insulina e glutamato aumentando os níveis de Klotho. De forma coerente, antagonismo de receptor AMPA ou NMDA suprime a expressão neuronal de Klotho. Também mostramos aqui que a forma solúvel da Klotho é capaz de induzir a glicólise aeróbica de astrócitos impedindo a metabolização do piruvato pela mitocôndria, e estimulando seu processamento pela lactato desidrogenase. Inibição farmacológica de FGFR1, fosforilação da ERK e de transportadores de ácidos monocarboxílicos previne a liberação de lactato induzida por Klotho em astrócitos. Inibição da AKT pelo tratamento com Klotho induz a atividade transcricional dos fatores de transcrição FOXO e promove proteção antioxidante em astrócitos pelo aumento de expressão de catalase. De forma similar, tratamento com a Klotho apresentou propriedades antiinflamatórias em astrócitos, impedindo ativação do fator de transcrição NF-<font face = \"symbol\">kB após estímulo com LPS. Em neurônios, tratamento com a proteína Klotho induz ubiquitiniação e degradação proteassomal de PFKFB3. Por fim, provamos que a quantidade de Klotho diminui em hipocampo de animais envelhecidos. Genes e proteínas relacionados ao metabolismo energético e ao acoplamento metabólico de neurônios e astrócitos tem padrão de expressão alterados no hipocampo com o envelhecimento, mostrando que essa pode ser uma característica importante para explicar o declínio cognitivo comum ao processo de envelhecimento. Em conjunto, esses dados sugerem que a Klotho pode ser um novo participante do acoplamento metabólico entre neurônios e astrócitos. / Mutations in the <font face = \"symbol\">b-glucuronidase protein Klotho have been associated with premature aging and cognitive dysfunction. Although highly expressed in specific regions of the brain, Klotho actions in the central nervous system are still largely unknown. Here we show that animals with a mutated hypomorphic Klotho gene have altered glycemia regulation, suggestive of a higher insulin sensitivity. In the central nervous system, pathways related to insulin intracellular signaling were shown to be up-regulated in the hippocampus, with higher AKT and mTOR activation, and inactivation of transcription factor FOXO. Here, we show that cultured hippocampal neurons respond to insulin and glutamate stimulation by elevating Klotho protein levels. Conversely, APA and NMDA antagonism suppress neuronal Klotho expression. We also provide evidence that soluble Klotho enhances astrocytic aerobic glycolysis by hindering pyruvate metabolism through the mitochondria, and stimulating its processing by lactate dehydrogenase. Pharmacological inhibition of FGFR1, ERK phosphorylation, and monocarboxylic acid transporters prevents Klotho-induced lactate release from astrocytes. AKT inhibition by Klotho treatment induces transcriptional activity of FOXO transcription factors and promote antioxidant defense in astrocytes by inducing catalase expression. Similarly, Klotho treatment has anti-inflammatory properties, as shown by its ability to hinder NF-<font face = \"symbol\">kB activation in astrocytes after LPS stimulation. In neurons, Klotho treatment induces PFKFB3 ubiquitination and degradation through the proteasome. Lastly, in the hippocampus, we show that Klotho is less present in hippocampi of aged mice. Genes and proteins related to energy metabolism and metabolic coupling between neurons and astrocytes show an altered expression pattern with aging, suggesting that this could be a crucial characteristic that explains cognitive decline commonly seen during the aging process. Taken together these data suggest Klotho as a potential new player in the metabolic coupling between neurons and astrocytes.

Some interesting, biologically active natural products have been found to contain poly-azole fragments within their core. These fragments are linked through the 2- position of one azole and the 4-position of its neighbour. Decarboxylative cross-coupling methodology may provide a route to these desired linked azoles through cross-coupling of azole-4-carboxylic acids with azole-2- halides or with azoles containing no substitution at the 2-position. Investigations into the silver-mediated decarboxylation, and subsequent coupling potential, of thiazole and oxazole-4-carboxylic acids are reported. Methods towards the synthesis of novel chlorinated thiazole and oxazole acids and their precursors are also described. A method to successfully couple these acids to aryl iodides has been developed and the scope of this reaction extended to a variety of functionalised azole-4-carboxylic acids. Attempts to extend this methodology and combine the decarboxylative coupling with CH activation of a second azole are also described.

Au Yuen-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 140-152). / Abstracts in English and Chinese. / Abstract --- p.iii / Acknowledgements --- p.v / Chapter Chapter One: --- General Background and Introduction --- p.1 / Chapter 1 -1 --- Introduction --- p.1 / Chapter 1-2 --- Three-Bond Coupling Constants (3J) --- p.1 / Chapter 1-2-1 --- Development of the Karplus Equation --- p.1 / Chapter 1-2-2 --- Application of3J in the Conformational Analysis of Nucleic Acid --- p.4 / Chapter 1-2-3 --- Problem of Accuracy for3 J Measurement --- p.7 / Chapter 1-3 --- Two-Bond Coupling Constants (2J) --- p.7 / Chapter 1-3-1 --- The Use of the Projection Method --- p.7 / Chapter 1-3-2 --- 2J Coupling Constant Involving Hydrogen Bonds --- p.8 / Chapter 1-4 --- One-Bond Coupling Constants (1J) --- p.10 / Chapter 1-5 --- Conclusion --- p.11 / Chapter Chapter Two: --- Experimental Section / Chapter 2-1 --- Introduction --- p.12 / Chapter 2-2 --- Heteronuclear Multiple-Quantum Coherence (HMQC) Experiment --- p.12 / Chapter 2-3 --- Experimental Section --- p.15 / Chapter 2-3-1 --- Sample Preparation --- p.15 / Chapter 2-3-2 --- NMR Spectroscopy --- p.16 / Chapter Chapter Three: --- Theory of Nuclear Spin-Spin Coupling Constants --- p.18 / Chapter 3-1 --- Introduction --- p.18 / Chapter 3-2 --- Application of Finite Perturbation Theory on Nuclear Spin-Spin Coupling --- p.18 / Chapter 3-3 --- Methodology --- p.22 / Chapter Chapter Four: --- DFT and NMR Study of1JCH Coupling Constants --- p.28 / Chapter 4-1 --- Introduction --- p.28 / Chapter 4-2 --- Nomenclature and Definition of Structural Parametersin DNA and RNA --- p.28 / Chapter 4-2-1 --- "Nomenclature, Symbols and Atomic Numbering Schemes" --- p.28 / Chapter 4-2-2 --- Definition of Torsion Angles and their Rangesin Nucleotides --- p.31 / Chapter 4-2-3 --- Description of the Furanose Ring --- p.31 / Chapter 4-3 --- Results and Discussion --- p.37 / Chapter 4-3-1 --- Basis Set Effect --- p.37 / Chapter 4-3-2 --- Relative Conformational Energy Profiles --- p.37 / Chapter 4-3-3 --- Comparison of the Dependence of 1JCH Coupling Constants on Conformational Changes With and Without the DNA Backbone --- p.40 / Chapter 4-3-4 --- Effect of Backbone 3'- and 5'-Phosphate --- p.42 / Chapter 4-3-5 --- Effect of Glycosidic Torsion Anglex --- p.49 / Chapter 4-3-6 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.52 / Chapter 4-3-7 --- Effect of Torsion Angle α --- p.52 / Chapter 4-3-8 --- Effect of Torsion Angle β --- p.53 / Chapter 4-3-9 --- Effect of Torsion Angle γ --- p.56 / Chapter 4-3-10 --- Effect of Torsion Angle ε --- p.59 / Chapter 4-3-11 --- Effect of Torsion Angle ζ --- p.61 / Chapter 4-3-12 --- Effect of Base Pairing --- p.65 / Chapter 4-3-13 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.65 / Chapter 4-3-14 --- Comparison of Experimental and Theoretical Data --- p.68 / Chapter 4-4 --- Conclusion --- p.74 / Chapter Chapter Five: --- DFT Study of 2JCH and 3JCH Coupling Constants --- p.79 / Chapter 5-1 --- Introduction --- p.79 / Chapter 5-2 --- Results and Discussion on 2JCH Coupling Constants --- p.79 / Chapter 5-2-1 --- Effect of Backbone 3'- and 5'-Phosphate --- p.79 / Chapter 5-2-2 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.82 / Chapter 5-2-3 --- Effect of Glycosidic Torsion Anglex --- p.87 / Chapter 5-2-4 --- Effect of Torsion Angleγ --- p.87 / Chapter 5-2-5 --- Effect of Torsion Angle ε --- p.90 / Chapter 5-2-6 --- Effect of Base Pairing --- p.90 / Chapter 5-2-7 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.90 / Chapter 5-3 --- Results and Discussion on 3JCH Coupling Constants --- p.95 / Chapter 5-3-1 --- Effect of Backbone 3'- and 5'-Phosphate --- p.95 / Chapter 5-3-2 --- Effect of Ring Conformation with Fixed Glycosidic Torsion Anglex --- p.95 / Chapter 5-3-3 --- "Effect of Different Torsion Angles (X,α,β,γ,ε,and ζ)" --- p.100 / Chapter 5-3-4 --- Effect of Base Pairing --- p.100 / Chapter 5-3-5 --- Effect of Base Stacking from the (n-1) and (n+1) Base --- p.105 / Chapter 5-4 --- Conclusion --- p.105 / Chapter Chapter Six: --- Conclusion --- p.111 / Appendix A Product Operator Formalism on HMQC Pulse Scheme --- p.113 / Appendix B Finite Perturbation Theory --- p.115 / Appendix C Supplementary Figures of Chapter Four --- p.118 / Appendix D Some of the NMR Spectra --- p.134 / References --- p.140

Neste trabalho apresentamos condições suficientes para a obtenção de taxas exponenciais de convergência na lei multidimensional dos grandes números para campos aleatórios definidos em R^Z_d. Dentre possíveis aplicações do resultado apresentamos medidas não-gibbsianas e não-FKG (limites de saturaçãoo de processos de estacionamento) e medidas estacionárias originárias de sistemas de partículas (rede com perdas, incluindo o caso onde há interação de longo alcance com cauda pesada). / We describe sufficient conditions for the occurrence of exponential rates of convergence in the multidimensional law of large numbers for random fields in RZd . Non-gibbsian and non-FKG measures from statistical mechanics (jamming limits of RSA models) and IPS (stationary measures of loss networks, including heavy-tail long-range interaction) are indicated as examples where the result applies.

Organometallic compounds derived from tin, boron, and zinc, have been used extensively in transition metal-catalysed cross-coupling, and continue to hold status as the go-to reagents to form new carbon-carbon bonds. Recently, organosilicon compounds have emerged as an attractive alternative to these established reagents, benefitting from low toxicity, low cost, and general ease of handling. While the fundamental reactivity of arylsilane reagents (Ar-SiR3) is well known, their role in transition metal-catalysed reactions is generally less well studied. This thesis comprises an investigation into the effect of ortho-substitution of these arylsilane reagents, and specifically, their application in gold-catalysed direct arylation. In Chapter 2, the transmetalation of these reagents to gold(III) is assessed using a combination of in situ reaction monitoring coupled with kinetic simulations. This allowed a scale of reactivity to be constructed for a range of structurally diverse arylsilanes, and uncovered that more sterically hindered arylsilanes actually exhibit accelerated rates of transmetalation. In Chapter 3, the reactivity of ortho-substituted arylsilanes in gold-catalysed arylation is addressed. The majority of arylsilanes tested in the previous chapter were found to be unable to undergo coupling, despite the viability of transmetalation having been demonstrated. Slight modification of the ortho-substituent, to incorporate a tethered ligand, was found to have a dramatic effect on reactivity, and allowed the coupling of a variety of substrates. The nature of the ligand, as well as the substitution of the tether was found to have a significant impact on the rate of coupling. Chapter 4 describes the way in which the reactivity of ortho-substituted arylsilanes might be exploited in a 'Catch and Release' protocol for catalyst recovery. This aims to combine the established benefits of homogeneous and heterogeneous catalysis to offer an alternative to current methods of catalyst recycling in industrial chemistry. A number of different 'Catch and Release' mechanisms were considered, and the validity of the concept was demonstrated in a monophasic system.