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Kinetic Studies of the Sulfoxidation of Aryl Methyl Sulfides by Trans-Dioxoruthenium(VI) Porphyrin ComplexesAbebrese, Chris 01 December 2009 (has links)
The development of an efficient, catalytically active, biomimetic model for cytochrome P-450 enzymes has been an area of intense research activity. Ruthenium porphyrin complexes have been the center of this research and have successfully been utilized, as catalysts, in major oxidation reactions such as the hydroxylation of alkanes, the epoxidation of alkenes and aromatic rings, and the N-oxidation of amines, among others. In this project, the kinetics of two-electron sulfoxidation of para-substituted phenyl methyl sulfides to the corresponding sulfoxides with well-characterized trans-dioxoruthenium(VI) porphyrin complexes were studied by rapid stopped-flow spectroscopy. The substituent effect in sulfides and in dioxoruthenium(VI) complexes were also kinetically investigated. The low-reactive trans-dioxoruthenium(VI) porphyrin complexes (3a-b) were synthesized from the oxidation of their carbonylruthenium(II) porphyrin precursors with m-chloroperoxybenzoic acid (m-CPBA) and characterized spectroscopically by 1H-NMR, IR, and UV-vis. The low-reactivity of these complexes makes them suitable for kinetic studies. The sulfoxidation with the trans-dioxoruthenium(VI) species followed a pseudo-first order kinetic decay from RuVI to RuIV species with no accumulation of intermediates. The reactivity order in the series of dioxoruthenium(VI) complexes follows 3b > 3a >3c, which is consistent with expectations based on the electrophilic nature of high-valent metal-oxo species. Steric effect of the substituents on the complexes also affected the reactivity order. The kinetic results revealed that the sulfoxidation reaction with these well-characterized dioxoruthenium(VI) complexes is 3 – 4 orders of magnitude faster than the epoxidation reaction with the same complexes under similar conditions.
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Multiplexed antibody kinetics using the Interferometric Reflectance Imaging SensorNeedham, James William 13 June 2019 (has links)
Label free detection of biologically relevant binding pairs has provided critical insight into the characterization of reagents used in both therapeutic and diagnostic applications. The Interferometric Reflectance Imaging Sensor (IRIS) platform has been developed for the multiplexed, real-time detection of such binding interactions. Improvements to experimental methodology and analysis applied to the latest iteration of the IRIS provided heretofore unseen binding characterizations with this multiplexed platform. Here, we extend and demonstrate the utility of the IRIS system to (1) evaluate and compare kinetic parameters to those obtained with more traditional label free methods (2) characterize multiple, disease relevant antibodies in multiple disease systems (anthrax, Zika, dengue and plague) (3) determine appropriate binding pairs in multiplexed label free formats and (4) obtain 10-fold improvements to the limits of detection for analyte in solution over previous IRIS iterations. Applications to immunoassay development are discussed throughout with exemplary datasets provided. Observations regarding additional IRIS utilities are also discussed, including qualifications of genetically engineered ligands, evaluating subcloned antibodies and screening unpurified antibody supernatants.
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Physico-chimie d'adhésifs polymérisés par voie non conventionnelle et adhérence sur alliage base aluminium / Physical chemistry of adhesives cured on demand and adhesion on aluminum alloysGenty, Sébastien 30 November 2018 (has links)
L’utilisation d’adhésifs polyépoxy et plus particulièrement de pâte de calage dans l’aéronautique est chose très courante. L’augmentation des cadences de production des aéronefs poussent les fournisseurs à adapter les temps technologiques de ces produits (temps d’application et de complète polymérisation) : ainsi, la cinétique de réticulation des adhésifs de demain devra être lente à température ambiante et pouvant être accélérée à tout moment. Pour cela, la piste envisagée pour ces tra-vaux est la polymérisation sous rayonnement infrarouge. La cinétique de ré-action a été évaluée par analyse thermique (DSC) ou par analyse spectrosco-pique (MIR ou PIR). Les résultats obtenus ont mis en évidence un effet thermique et non thermique du rayonnement infrarouge. Grâce à plusieurs expérimentations, les résultats montrent que le rayonnement infrarouge interagit avec les groupe-ments époxydes dont l’énergie d’activation de la réaction avec les amines primaires diminue. Par ailleurs, l’utilisation d’un plan d’expérience a permis de montrer que l’adhérence et les propriétés mécaniques de ces adhésifs augmentaient suite à l’utilisation du rayonnement infrarouge. / The use of polyepoxy adhesives and more particularly of liquid shim in aero-nautics is very common. The increase in aircraft production rates is pushing suppli-ers to adapt the technological times of these sort of products (application and complete curing times): thus, the curing kinetics of tomorrow's adhesives must be slow at room temperature and can be accelerated at any time. For this purpose, this work paves the way of an infrared curing. The reaction kinetics were evalu-ated by thermal analysis (DSC) or spectroscopic analysis (MIR or NIR). The results obtained showed a thermal and non-thermal effects of infrared radiation. Thanks to several experiments, the results show that infrared radiation interacts with epoxide groups whose activation energy with primary amines reaction decreas-es. In addition, by the use of Design of Experiment (DoE) showed that the ad-hesion and mechanical properties of these adhesives increased as a result of the use of infrared radiation.
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