Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 16 of 16 for “"Nitroxides"”.
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Nitroxides in Mechanistic Studies: Ageing of Gold Nanoparticles and Nitroxide Transformation in Acids
… inhibition mechanism and associated chemistry of nitroxides in self-initiated polymerization of acrylic acid was investigated. The synergism of nitroxides with other types of inhibitors was proposed. An unusual decay of nitroxide radicals in acid at high temperature was observed. Following Chapter …
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Metabolically Responsive Contrast or Imaging Agents for NMR or ESR Imaging: Metabolism of Nitroxides in Cells
… need to understand thoroughly the metabolism of nitroxides in cells. A fundamental investigation of the metabolism of nitroxide in cells is presented in this thesis.
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Effect of Nitroxides and Molecular Oxygen on Proton Relaxation Rates in Aqueous Systems and in Lipids
A fundamental investigation of the potential of nitroxides and O$\sb2$ for enhancement of magnetic resonance imaging (MRI) contrast in vivo is presented. The effect of these species on proton relaxation in both aqueous systems and in lipids is studied. The basic experimental approach for this study …
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Nitroxide Spin Labels as NMR Contrast Agents: Delivery, Metabolism and Relaxation
In this project, the potential of nitroxides as contrast agents for magnetic resonance imaging (MRI) has been studied. The difficulties involved in using nitroxides as in vivo MRI contrast agents, such as premature metabolic convertion of nitroxides to their nonparamagnetic state, lack of tissue …
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Electron Spin Resonance Studies of the Addition of Nitrogen Dioxide to Alkenes
… alkyl-substituted alkenes to produce dialkyl nitroxides, and react with a, β-unsaturated carbonyl compounds to produce iminoxy radicals. Most of these reaction mixtures when kept unexposed to air, and light over a period of time showed the decay of nitroxides, and iminoxy radicals, and the …
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Dinitroxides in Rapid Scan Electron Paramagnetic Resonance Imaging
… such as triarylmethyl (Trityl) radicals or nitroxides. Attention is given here to an example of a nitroxide that has been structured to provide longer intercellular retention time. In addition to the use of nitroxides as probes, they can also be utilized as nuclear magnetic resonance imaging …
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Applications of fluorescence spectroscopy to environmental chemistry
… dissolved organic matter (DOM) fluorescence by nitroxides is employed to investigate the electrostatic propertie~ of DOM in aqueous solution, with the goal of elucidating the apparent ionic strength and pH dependence of metal-fulvic acid binding constants. In part three, the intrinsic optical …
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Cyclodextrin-based rotaxanes for material science applications
… were explored. Encapsulation of profluorescent nitroxides through rotaxane formation demonstrated the use of CD-based rotaxanes to change the reactivity of CD guests and therefore preserve their properties. In Chapter 2, the rotaxane 1.17 having a stilbene-based axle and 3,5-dimethylaniline …
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Cyclodextrin-based rotaxanes for material science applications
… were explored. Encapsulation of profluorescent nitroxides through rotaxane formation demonstrated the use of CD-based rotaxanes to change the reactivity of CD guests and therefore preserve their properties. In Chapter 2, the rotaxane 1.17 having a stilbene-based axle and 3,5-dimethylaniline …
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The synthesis of a ferromagnetic polymer
… of phenylacetylenes bearing nitronyl nitroxides and nitro/cyano groups. The magnetic properties of the materials were determined using a SQUID magnetometer. A novel rhodium catalyst, Rh(NBD)(NH3)Cl, was prepared in order to obtain good yields of polymerisation. A wide range of …
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Molecular dynamics simulation study of the stability and conformation of spin-probe labeled DNAs
… and Sybyl programs lack suitable parameters for nitroxides. These force fields were modified to contain new types of atoms designated as N.rad and O.rad with slightly different values than those reported by Barone, et al. for MM3 and MM+ force fields (Barone et al., J. Am. Chem. Soc. 1998, 120, …
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Rapid Scan Electron Paramagnetic Resonance (EPR) and Digital EPR Development
… scan to wider spectra, such as for immobilized nitroxides, spin-labeled proteins, irradiated tooth and fingernail samples were demonstrated in this dissertation. The scan width has been increased from 55 G to 160 G. The signal to noise (<em>S/N</em>) improvement for slowly tumbling spin-labeled …
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Controlled Radical Polymerization: Towards Industrially Relevant Conditions
… barrier to commercialization. Indeed, certain nitroxides are currently produced at pilot scale. However, limited research has been conducted into continuous operation which is commonly used in industry to improve productivity. A batch NMP study at elevated temperatures demonstrates the …
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Redox Mediators and Electrolytes for High-Performance Li-O₂ Batteries
… of the imidazole ring, and phenyl nitronyl nitroxides (RPTIOs) with varied substituents on the benzene ring. The compounds were characterized using NMR and FTIR together with elemental analysis, TGA, DSC and EIS for TEMPOImILs. Redox processes were studied using cyclic voltammetry and, for …
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Applications of EPR with an Emphasis on Tau Fibril Structure
… from 0.25-34 GHz, guiding synthesis of improved nitroxides for <em>in vivo</em> imaging experiments. Processes contributing to T<sub>1</sub> of DPPH in polystyrene were found through variable temperature measurements at X- and Q-band, resolving previously-reported discrepancies in relaxation …
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Spin Chemistry of Guest@Host Systems: H₂@C₆₀ and Nitroxide@Octa Acid
This thesis describes the nuclear and electronic spin chemistry of incarcerated guest molecules to form a guest@host complex in conjunction with the utility of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy. The first chapter describes the background and …