The study of high-speed flows represents a challenging problem in the fluid dynamics field due to the presence of chemical reactions and non-equilibrium effects. Hypersonic flights, where speeds reach Mach 5 and above, are particularly influenced by these effects, resulting in a direct impact on the flow and consequently on the aerodynamic performance of a vehicle traveling at these speeds. The study of hypersonic flow conditions requires the experimental capability of determining local temperatures, pressures and velocities using non-intrusive techniques. Furthermore, the simultaneous measurement of two or more variables in a complex flow boosts the amount of information that is obtained since valuable correlations can be established. This research includes the design, construction and characterization of a hypersonic flow apparatus explicitly intended as a tool for advanced laser diagnostics development. This apparatus is characterized by its pulsed operation mode that translates into a significant reduction in mass flow rates and can be operated for long periods at Mach numbers ranging from 2.8 to 6.2. The flow conditions during the uniform flow time interval of each pulse vary by less than 1%, generating a flow of sufficient quality for quantitative measurements. The development of a laser diagnostic technique, the VENOM technique, which is a non-intrusive method to provide simultaneous 2-D measurements of the mean and instantaneous fluctuations in two-component velocity and temperature is also presented. This technique represents the first single diagnostic capable of instantaneous two-component velocimetry and thermometry in a gaseous flow field by combining two Nitric Oxide Planar Laser Induced Fluorescence methods: two-component Molecular Tagging Velocimetry and two-line thermometry, employing the nascent NO(v"=1) arising from the NO2 photodissociation as a molecular tracer. The VENOM technique is expected to be not only applicable to cold high-speed flows, which is the focus of the present work, but also to combustion and other reactive or high-enthalpy flow fields.

Lab-on-a-chip (LOC) biological assays have the potential to fundamentally reform healthcare. The move away from centralized facilities to Point-of-Care (POC) testing of biological assays would improve the speed and accuracy of these, thereby improving patient care. Before LOC can be realized, a number of challenges must be addressed: the need for expert users must be abstracted away; the manufacturing cost of $5 per test threshold must be met; and the supporting infrastructure must be integrated down to an easily portable size. These challenges can be addressed with the deposition of microfluidics on CMOS chips. By designing application specific integrated circuits (ASICs) much of the automation and the supporting infrastructure needed to run these assays can be integrated into the chip. Additionally, CMOS fabrication is some of the most optimized manufacturing in industry today. One of the central challenges with LOC on ASIC is the signal acquisition from the microfluidics into the CMOS. Optical sensing of fluorescence is one form of sensing used for LOC assays. Despite a large literature, there has not been a strong demonstration of monolithic LOC fluorescence detection (FD) for low concentration samples. This work explores the limit-of-detection (LOD) for LOC FD through analysis of the signal and noise of a proposed acquisition channel. The proposed signal acquisition channel consists of an on chip photodiode and integrator based amplification circuits. A hand analysis of the signal propagation through the channel and the noise sources introduced by the circuitry, is performed. This analysis is used to establish relationships between different circuit parameters and the LOD of a hypothetical LOC device. The hand analysis is verified through simulation and the acquisition channel is implemented in: (i) the Austrian Microsystems 350nm CMOS process, (ii) discrete components. Testing of the CMOS chip revealed several issues not identified in extracted simulation; however, the discrete integrator demonstrated many of the trends predicted by the hand analysis and simulations and achieved a LOD of 7.2$\mu M$. This analysis provides insight into the engineering trade-offs required to improve the LOD, to enable more wide spread application of LOC FD.

The interaction of different formulations of the antifungal drug amphotericin B (AmB) with model cell membranes was studied and new techniques of measuring this interaction using electrochemical and/or spectroscopic methods were developed. Two model cell membrane systems were used: sterol-free lipid monolayers adsorbed to a Hg electrode and sterol-free or sterol-containing floating lipid monolayers on a Langmuir trough. Electrochemical control over the adsorbed monolayer allowed the defectiveness of the layer to be varied and the interaction of AmB with both well-ordered and defective monolayers characterized. Measurements of monolayer capacitance and permeability were used to indicate the nature of the interaction. Capacitance provides a measure of the lipid organization, while permeability was measured via electro reduction of thallium (I)cation. The three AmB formulations and two control samples were examined and showed different interaction behaviour. The disruption of lipid order and permeabilization induced by the two commercial formulations correlated generally with in vivo studies of their toxicity. An experimental and possibly less toxic AmB formulation made monolayer significantly more permeable. In situ fluorescence microscopy of the monolayer on Hg was carried out after introducing a low concentration of fluorophore into the layer. Fluorescence intensity as a function of electrode potential was measured and was used to characterize the lipid on Hg model membrane system before we attempted to measure AmB's influence on the fluorescence. The fluorescence excitation and emission spectra of AmB itself were measured ex situ for two of the formulations. Using added surfactant to control AmB aggregation state, the relationship between AmB aggregation and its fluorescence properties was examined. We discovered AmB to have unusual dual fluorescence properties, the extent of which differed between formulations. We measured AmB's fluorescence in situ as the drug interacted with floating lipid monolayers on the Langmuir trough. Both the variation in fluorescence during compression of a mixed AmB/lipid monolayer and penetration of AmB into a phospholipid monolayer were measured. This experimental setup was configured to collect fluorescence only from AmB at the monolayer, and not from AmB in bulk solution. Fluorescence excitation was made using a laser diode extracted from a consumer electronics device.

It is well known that boronic acids can bind with diols and can be further applied as chemosensors for biomolecules such as carbohydrates and dopamine. Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents.

In this Medical Physics M.Sc. project, a near-infrared (NIR) fluorescence imaging system was built for in-vivo diagnosis and evaluation of pigmented skin abnormalities and diseases. Light coming from a 785 nm diode laser is coupled into a ring light guide to uniformly illuminate the skin surface with a field-of-view (FOV) of 25 mm diameter. The diffuse reflectance and emitted fluorescence photons are collected by an NIR-sensitive CCD camera, with computer-controlled filter switch to select between reflectance mode and fluorescence mode. Both reflectance and fluorescence images of skin disorders were obtained with an exposure time of 2 seconds. The results show that cutaneous melanin in pigmented skin disorders emits higher NIR autofluorescence (AF) than surrounding normal tissue. This finding challanged the conventional concept that melanin is a non-fluorescence substance. The developed NIR autofluorescence imaging method also provided a new and direct way to characterize cutaneous melanin and can potentially be used for evaluation and diagnosis of pigmented skin diseases and skin cancers, such as melanoma.

In this Medical Physics M.Sc. project, a near-infrared (NIR) fluorescence imaging system was built for in-vivo diagnosis and evaluation of pigmented skin abnormalities and diseases. Light coming from a 785 nm diode laser is coupled into a ring light guide to uniformly illuminate the skin surface with a field-of-view (FOV) of 25 mm diameter. The diffuse reflectance and emitted fluorescence photons are collected by an NIR-sensitive CCD camera, with computer-controlled filter switch to select between reflectance mode and fluorescence mode. Both reflectance and fluorescence images of skin disorders were obtained with an exposure time of 2 seconds. The results show that cutaneous melanin in pigmented skin disorders emits higher NIR autofluorescence (AF) than surrounding normal tissue. This finding challanged the conventional concept that melanin is a non-fluorescence substance. The developed NIR autofluorescence imaging method also provided a new and direct way to characterize cutaneous melanin and can potentially be used for evaluation and diagnosis of pigmented skin diseases and skin cancers, such as melanoma.

Le besoin de concevoir des systèmes de détection efficaces de diverses substances afin d'améliorer le contrôle de qualité et la sécurité environnementale, nous amène à chercher de nouvelles approches pour contourner les problèmes reliés aux systèmes de détection actuels, tels leur taille, coût, sélectivité et consommation d'énergie. Il est aussi souhaitable de définir un modèle de développement qui ne soit pas contraint par le besoin d'une connaissance précise des processus physiques sous-jacents, souvent inconnus. Ce mémoire décrit la mise en oeuvre partielle d'un dispositif permettant d'identifier et de mesurer la concentration de substances fluorophoriques dans un milieu optique typique (Solution liquide ou suspension dans un fluide). La méthode est basée sur des mesures de fluorescence multispectrales, réalisées en excitant une substance inconnue avec une ou plusieurs diodes électroluminescentes qui couvrent un intervalle de longueurs d'ondes donné. La conception du détecteur photoélectrique repose sur la propriété inhérente des diodes électroluminescentes d'agir comme détecteurs photoélectriques quand elles sont polarisées à l'envers, et cela en offrant une réponse spectrale qui dépend de leur couleur. Dans ce mémoire, on propose un système dont l'entrée est composée d'une diode excitatrice et d'un ensemble de diodes électroluminescentes de différentes couleurs qui détectent la lumière à différentes longueurs d'ondes. Les données acquises par les photodiodes sont transmises à un système d'amplification puis à un convertisseur analogique numérique avant d'être acheminées vers un microcontrôleur implémenté sur une puce FPGA. Ce dernier permet de commander le processus de saisie des données et l'affichage des résultats obtenus quant au type et à la concentration des données obtenues. Un réseau de neurones artificiel (RNA) codé en logiciel réalise le traitement des données requis. Ce mémoire couvre tous les aspects du design sauf celui du RNA. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Mesure de fluorescence, Photodiode, FPGA, MicroBlaze.

The present work utilizes single molecule methods and analysis to investigate soft and hard substrates. First, the effect of charged hard surfaces on charged probes were evaluated, as the soft surfaces were built upon such a structure. Then, selected polymers were selected according to their importance in smart surface technology. The extent of interaction of the selected probes with the array of soft surfaces gives insight to the potential tunability of these surfaces. The three distinct polymers range from ubiquitous usage to advancements in current technology. The studies presented here are needed to characterize, on the nanoscale, the Coulombic interactions of these polymers.

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The optical properties of transparent chromium-doped glass-ceramics with the chemical composition similar to that of cunyite (Cr 4+ :Ca 2 GeO 4 ) crystal were investigated. Room temperature absorption, DTA, XRD as well as fluorescence were measured. Parent (as quenched) glass does not exhibit any fluorescence; after the heat treatment Cr 4+ fluorescence band appears at 1280 nm, very similar to the emission of Cr 4+ :Ca 2 GeO 4 bulk crystals. Optical properties of nanocrystals formed in the glass-ceramics. The size of crystallites is below 600nm. glass-ceramics we concluded that the nanocrystal phase is a modified Ca 2 GeO 4 structure. In order to increase the fluorescence and synthesis more small crystals, we doped TiO 2 and ZrO 2 as nucleating agents, glass does not exhibit any fluorescence when glass-ceramics does not heat treatment ; after the heat treatment Cr 4+ fluorescence band appears at 1280 nm too. The crystals formed in glass media after heat-treatment have spherulitic shape with the size up to 300-500nm, and there are more nanocrystals distribute the surface, especially doped TiO 2 we found the more smaller crystals in it. We expect that crystallites with the size below 100 nm may be formed by adjustment of initial glass composition with nucleating agents and optimization of heat-treatment procedure parameters.