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.
Results
Showing 1 to 20 of 63 for “"Nitroxide"”.
-
Analysis of the microwave spectrum of the bis-trifluoromethyl nitroxide
… of the stable free radical bis-trifluoromethyl nitroxide was analyzed in the 20 to 26.5 GHz region. 39 transitions have been assigned. The rigid rotor rotational constants determined by calculation of the hypothetical unsplit rotational transitions are A= 2256.94 MHz, B= 1056.08 MHz, and …
-
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 …
-
Spin Chemistry of Guest@Host Systems: H₂@C₆₀ and Nitroxide@Octa Acid
… the electron spin chemistry of a paramagnetic nitroxide molecule incarcerated inside a capsule (nitroxide@octa acid) and presents supramolecular effects on paramagnetic interaction between the nitroxide incarcerated inside the capsuleplex with the nitroxide in bulk aqueous media studied by …
-
Nitroxides in Mechanistic Studies: Ageing of Gold Nanoparticles and Nitroxide Transformation in Acids
… in this thesis includes the applications of nitroxide in the mechanistic studies of two very different research topics. Chapter 2 describes the investigation of ageing of gold nanoparticles (AuNPs) and its mechanistic implications. By utilizing a customized bisnitroxide disulfide, ligand …
-
Investigation of nitroxide-mediated thermal and photochemical reactions of living free radical polymerization.
… reaction between a carbon centered radical and a nitroxide radical involved in LFRP. Typical values lay in the area of 108 M-1 s-1 and are influenced by the structure of the carbon centered radical and not that of the nitroxide. The rate constants were observed to be slower with more stable carbon …
-
Electron Spin Resonance Measurements and Studies of Intracellular Oxygen Concentrations and Nitroxide Metabolism
The concentration of molecular oxygen within cells plays a crucial role in many physiological and pathological processes. There are, however, very few data on actual intracellular oxygen concentrations, due largely to the lack of a suitable measurement technique. We have employed the techniques of …
-
Nitroxide Radical - Transition Metal Interactions and Mixed-Metal Complexes of Some Binucleating Ligands
Made available in DSpace on 2014-12-13T20:10:13Z (GMT). No. of bitstreams: 1 7804057.pdf: 5105683 bytes, checksum: 99854e44992c21abb80cfad6be6b9777 (MD5) Previous issue date: 1977
-
The 1H and 13C dynamic nuclear polarization (DNP) enhancement for novel silica phase immobilized nitroxide (SPIN) samples
… have established that silica phase immobilized nitroxide (SPIN) radical system are advantageous in the SLIT experiment. In favorable cases (e.g. DCCI₃/SPIN system) a ¹³C DNP enhancement 60 times in excess of the high magnetic field (4.7 T) magnetization has been achieved.¹² However a number of …
-
Advancements in branched bottlebrush polymers for responsive, targeted imaging
… rates. We reasoned that through the use of a nitroxide radical MRI contrast agent along with a NIR fluorophore it would be possible to study these phenomena along with nitroxide reduction in vivo. Thus, we have developed branched bottlebrush copolymers that display compensatory fluorescence …
-
Molecular dynamics simulation study of the stability and conformation of spin-probe labeled DNAs
Nitroxide based spin-probes, observable by ESR, have been used to study protein structure and protein-substrate interactions. More recently, spin-probe labeled DNAs have been introduced to study its structure and dynamics. Molecular modeling has proven to be an increasingly powerful tool for …
-
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 …
-
Metabolically Responsive Contrast or Imaging Agents for NMR or ESR Imaging: Metabolism of Nitroxides in Cells
The use of nitroxide spin labels in complex biological systems as biophysical tools to study molecular dynamics of membranes and cells and as contrast or imaging agents for NMR or ESR imaging and in vivo spectroscopy has led to a need to understand thoroughly the metabolism of nitroxides in cells. …
-
Synthesis and Characterization of Tailored Macromolecules via Stable Free Radical Polymerization Methodologies
… and the molar ratio of initiator to nitroxide demonstrated no significant control over the resulting polymer products. Analysis of the polymerization kinetics for a 2-vinylnaphthalene polymerization performed in the presence and absence of the free radical initiator revealed identical …
-
Lanthanide Functionalised gold nanoparticles as MRI contrast agents
… nanoparticles were also used as templates for nitroxide based redox sensitive MRI contrast agents. The reducing behaviour and relaxivity of nitroxide protected AuNPs was measured and found slightly better than that of free nitroxide. Finally other useful applications of nanoparticles protected …
-
Mapping viability and oxygen concentration in spheroids: A noninvasive approach with EPR imaging
… throughout the spheroid of an aqueous nitroxide with a lineshape (linewidth) responsive to local (O$\sb2$); and (2) the selective exclusion from cells with intact plasma membranes (viable cells) of a contrast agent which broadens the lineshape of the nitroxide. Therefore, it is …
-
Triplex formation as monitored by EPR spectroscopy and molecular dynamics studies of spin -probe -labeled DNAs
… important molecules. Since the advent of nitroxide based spin-probes the electron paramagnetic resonance (EPR) study of spin-labeled macromolecules has been able to provide insight into structural and dynamics properties of DNAs, proteins, and related systems. Spin labels have been …
-
Approaches to intermolecular structure elucidation utilizing NMR and DNP parameters
… of compounds with both a LSR moiety and a nitroxide radical moiety in the same molecule were examined. LLIT DNP transfer experiments for the intramolecular LSR-nitroxide radicals molecular system and the intermolecular LSR—radicals systems were studied. Conclusions based on this study …
-
Non-Covalent Interactions in Block Copolymers Synthesized via Living Polymerization Techniques
… via living polymerization techniques such as nitroxide mediated polymerization and anionic polymerization. The influence of non-covalent association on the structure/property relationships of these materials were studied in terms of physical properties (tensile, DMA, rheology) as well as …
-
Developing novel polymer architectures for applications In magnetic resonance imaging and self-assembly
… and sterically hindered bis(spirocyclohexyl) nitroxide free radicals. This approach enables facile tuning of nitroxide loading percentages and molecular size. Bottle-brush ORCAs displayed high r₁ and r₂ relaxivities suggesting that they have potential for further in vivo MRI studies. Next, …
-
Noninvasive Temperature Measurements Using Electron Paramagnetic Resonance Spectroscopy
… measurements in living systems. We use the nitroxide, 3-doxyl-5$\alpha$-cholestane, mixed in 1 mol% cholesterol and 99 mol% methyl docosanoate and encapsulated in proteinaceous microspheres (average diameter $<$2 $\mu$m). We have shown a dramatic and measurable change in the EPR spectral …
Page 1 of 4