Дисертації з теми "Nuclear magnetic resonace spectroscopy"
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1
Patel, Sunil U. "Nuclear magnetic resonance spectroscopy and ultrasound." Thesis, Aston University, 1989. http://publications.aston.ac.uk/9708/.
Анотація:
The work described in this thesis is directed to the examination of the hypothesis that ultrasound may be used to perturb molecular motion in the liquid phase. These changes can then be detected by nuclear magnetic resonance (NMR) in spin-lattice and spin-spin relaxation times. The objective being to develop a method capable of reducing the pulsed NMR acquisition times of slowly relaxing nuclei. The thesis describes the theoretical principles underlying both NMR spectroscopy and ultrasonics with particular attention being paid to factors that impinge on testing the above hypothesis. Apparatus has been constructed to enable ultrasound at frequencies between 1 and 10 mega-hertz with a variable power up to 100W/cm-2 to be introduced in the NMR sample. A broadband high frequency generator is used to drive PZT piezo-electric transducer via various transducer to liquid coupling arrangements. A commercial instrument of 20 kilo-hertz has also been employed to test the above hypothesis and also to demonstrate the usefulness of ultrasound in sonochemistry. The latter objective being, detection of radical formation in monomer and polymer ultrasonic degradation. The principle features of the results obtained are: Ultrasonic perturbation of T1 is far smaller for pure liquids than is for mixtures. The effects appear to be greater on protons (1H) than on carbon-13 nuclei (13C) relaxation times. The observed effect of ultrasonics is not due to temperature changes in the sample. As the power applied to the transducer is progressively increased T1 decreases to a minimum and then increases. The T1's of the same nuclei in different functional groups are influenced to different extents by ultrasound. Studies of the 14N resonances from an equimolar mixture of N, N-dimethylformamide and deuterated chloroform with ultrasonic frequencies at 1.115, 6, 6.42 and 10 MHz show that as the frequency is increased the NMR signal to noise ratio decreases to zero at the Larmor frequency of 6.42 MHz and then again rises. This reveals the surprising indication that an effect corresponding to nuclear acoustic saturation in the liquid may be observable. Ultrasonic irradiation of acidified ammonium chloride solution at and around 6.42 MHz appears to cause distinctive changes in the proton-nitrogen J coupling resonance at 89.56 MHz. Ultrasonic irradiation of N, N-dimethylacetamide at 2 KHz using the lowest stable power revealed the onset of coalescence in the proton spectrum. The corresponding effect achieved by direct heating required a temperature rise of approximately 30oC. The effects of low frequency (20 KHz) on relaxation times appear to be nil. Detection of radical formation proved difficult but is still regarded as the principle route for monomer and polymer degradation. The initial hypothesis is considered proven with the results showing significant changes in the mega-hertz region and none at 20 KHz.
2
Norwood, Timothy John. "Nuclear magnetic resonance in inhomogeneous magnetic fields." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24875.
Анотація:
The work described in this thesis was initiated in an attempt to overcome the limitations imposed upon NMR spectroscopy by magnetic field inhomogeneity in two specific areas: high resolution spectroscopy in isotropic liquids, and chemical shift resolved NMR imaging in isotropic liquids.
In both cases magnetic field inhomogeneity may degrade the resolution of spectra to such an extent that no useful information can be obtained from them. In high resolution NMR spectroscopy it is necessary to be able to extract accurately the parameters present within the spectrum such as chemical shifts, coupling constants and peak areas. In chemical shift resolved imaging experiments the requirements are less stringent; and it is only necessary that the resonances of different chemical species be resolved. However, even the less stringent requirements of NMR imaging are often difficult to meet as the sample volumes required are often several orders of magnitude larger than those required in conventional high resolution NMR spectroscopy.
The use of zero-quantum coherence has been investigated as a potential solution to the magnetic field inhomogeneity problem in both of these areas. Zero-quantum coherences are independent of magnetic field inhomogeneity and contain the parameters desired in both cases, though they are displayed in a way which differs from conventional NMR spectra.
In this thesis, existing zero-quantum coherence experiments have been evaluated for use with inhomogeneous magnetic fields, and, where necessary, adapted for this purpose. Several completely new experiments have been developed for producing broad-band decoupled zero-quantum coherence spectra and also for presenting coupling constants and chemical shifts in a manner which is as close to conventional NMR spectra as possible, hence facilitating ease of use. Zero-quantum coherence has been evaluated as a tool for identifying unknown compounds and also for identifying the components of complex mixtures by "signature" recognition.
Both decoupled and non-decoupled zero-quantum coherence experiments are adapted to provide imaging experiments which allow the separation of the images of different chemical species in inhomogeneous magnetic fields. The two-dimensional J-resolved experiment is also adapted for this purpose.Science, Faculty of
Chemistry, Department of
Graduate
3
Wu, Xi-Li. "New techniques in nuclear magnetic resonance spectroscopy." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385872.
4
Claridge, Timothy David William. "Protein studies by nuclear magnetic resonance spectroscopy." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303628.
5
Wormald, Philip. "Nuclear magnetic resonance spectroscopy of vinylidenefluoride polymers." Thesis, Durham University, 2005. http://etheses.dur.ac.uk/2615/.
Анотація:
High-resolution solid- and solution state NMR techniques have been applied in the study of a Semi crystalline fluoropolymer Poly(vinylidienfluoride) (PVDF) and a vinylidienfluoride telomer. The application of standard solution-state experiments with high power decoupling and two-dimensional techniques has provided a greater understanding of the structure of these two fluoropolymers. Specifically, Cosy and Tocsy experiments gave information on signals normally related to end groups and to previously unidentified structures, which suggest the presence of at least a second major structure. 19F solid-state Magic Angle spinning Nuclear Magnetic Resonance (MAs- NMR) using relaxation filters in pulse sequences, has revealed fundamental differences relating to morphology and structure. The location of reverse units in the amorphous and crystalline domains is investigated by fluorine Tip filtered Radio Frequency Driven Recoupling (RFDR) and spin-diffusion experiments. These experiments proved that the reverse units are dominant in the amorphous phase, yet could have association with rigid species. Furthermore, signals generally associated with crystalline domains are not homogenie in character. The presence of a highly mobile species was detected and investigated using the delayed acquisition technique and T2 measurements. This showed the possibility of end-group signal in the spectral region normally associated with reverse groups. Furthermore, proton Tip measurements of nascent and annealed PVDF, recorded at variable temperature are related to molecular motion and debated with respect to the effect of spin diffusion on populations. The relationship between thermal events and thermal history of PVDF and its effect on molecular motion is debated.
6
Jones, David Nigel Mark. "Nuclear magnetic resonance spectroscopy of bacterial polysaccharides." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316713.
7
Xu, Ping. "New methods in nuclear magnetic resonance spectroscopy." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239177.
8
Cavanagh, John. "New techniques in nuclear magnetic resonance spectroscopy." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293707.
9
Barker, P. B. "New techniques in nuclear magnetic resonance." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375213.
10
Duce, Suzanne Louise. "Nuclear magnetic resonance imaging and spectroscopy of food." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240194.
11
Cousin, Samuel. "Two-field nuclear magnetic resonance : spectroscopy and relaxation." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066354/document.
Анотація:
Cette thèse traite de la RMN en phase liquide à champs multiples, pour la détermination de la structure et de la dynamique de petites molécules et de protéines. La dynamique ps-ns des chaînes latérales de la protéine ubiquitine a été étudiée par la relaxation du 13C des groupes méthyles δ1 des isoleucines, marqués sélectivement. Les vitesses de relaxation mesurées à plusieurs hauts champs magnétiques et les vitesses de relaxation longitudinale de 0.29 T à 9 T obtenues par relaxométrie haute résolution ont été analysées à l'aide du programme ICARUS, adapté à l’occasion pour les groupes méthyle. La matrice de relaxation a été calculée par un programme inédit, nommé RedKite. Un modèle de fonction de densité spectrale a été proposé pour prendre en compte les mouvements complexes des groupes méthyles. Nous avons ainsi pu accéder à une description de la dynamique des groupes méthyle sur trois ordres de grandeur d’échelles de temps. La spectroscopie RMN à deux champs magnétiques a été développée en collaboration avec Bruker. Le spectromètre à deux champs permet le contrôle des spins dans deux centres magnétiques avec une homogénéité suffisante et le transfert rapide de l’échantillon entre ces deux centres. Grâce à l'utilisation de cohérences à zéro-quantum, nous avons mesuré des spectres de corrélation homo- et hétéronucléaires à haute résolution dans lesquels les deux dimensions sont obtenues à deux champs très différents. Cette approche a été utilisée pour réduire considérablement la contribution de l’échange chimique à la relaxation transverse, permettant l’observation des signaux de noyaux en échange chimique invisibles à haut champWe present the development of multiple-field liquid-state NMR spectroscopy for the determination of the structure and dynamics of small molecules and proteins. Dynamics of proteins side-chains in the pico- to nanosecond range have been studied in the protein ubiquitin, by measuring the relaxation of carbon-13 nuclei in isoleucine-δ1 methyl groups, with site-specific isotope labelling. High-field relaxation rates and longitudinal relaxation rates obtained using high-resolution relaxometry have been analysed using a new version of the program ICARUS, adapted for methyl groups. The relaxation matrix has been calculated with a homemade program called RedKite. Models of spectral density function have been proposed to account for all motions of methyl groups. This unprecedented dataset allows for the description of motions in methyl groups over 3 orders of magnitudes of correlation times. Two-field NMR has been developed in collaboration with Bruker. The two-field NMR spectrometer allows for the control of nuclear spins in two magnetic centres with vastly different magnetic fields, coupled with a sample shuttle. Using zero-quantum coherences, homo and heteronuclear two-field high-resolution spectra have been obtained, where the two dimensions are acquired at very different magnetic fields. Such pulse sequences have been used to reduce the contribution of chemical exchange to transverse relaxation, even when this exchange makes signals invisible at high field. The reduced bandwidth of signals at low field has also been used to perform efficient isotropic mixing in a two-field TOCSY experiment. Correlations have been observed for carbon-13 signals separated by more than 150 ppm
12
Guitard, Pierre-André. "Local Nuclear Magnetic Resonance Spectroscopy with Giant Magnetoresistive Sensors." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS175/document.
Анотація:
La Spectroscopie par Résonance Magnétique Nucléaire (NMRS) est une technique largement connue pour l'analyse de molécules chimique et biologiques. Cependant, en raison de la faible intensité des signaux de RMN, il est très difficile de travailler sur des volumes inférieurs à un mm³. Cette limitation a conduit à la mise au point de capteurs miniaturisés tels que les microbobines, les centres NV et des magnétomètres atomiques. Au cours de cette thèse nous avons développé une approche basée sur l'utilisation de capteurs à MagnétoRésistance Géante (GMR), capteurs magnétiques à large de la bande, capable de détecter localement le signal RMN. Les capteurs GMR, sur différents substrats tels que le silicium, le verre et l’alumine, ainsi que la configuration du montage RMN ont été spécifiquement conçus pour avoir une détectivité dans la gamme de 20pt/sqrt(Hz) et capable de travailler avec un champ magnétique externe jusqu'à 1 Tesla. Nous allons d’abord présenter les résultats obtenus à 0.3T sur de l’eau, dans la configuration où la RMN locale est effectuée dans un grand volume, mettant en évidence le caractère fonctionnel du montage. Puis les résultats obtenus, également à 0.3T, de la spectroscopie RMN de liquides modèle comme l'éthanol où le volume sondé estimé est de l’ordre de 20x20x20μm³. Finalement un résultat à un champ magnétique plus élevé, 0.6T, a également été montré sur de l’eauNuclear Magnetic Resonance Spectroscopy (NMRS) is a widely known technique for chemical and biological molecule analysis. However due to the weakness of the NMR signals, it is very difficult to work on volumes lower than a mm³. That limitation has led to the development of miniaturized sensors such as microcoils, NV centers and atomic magnetometers. We will present our approach based on the use of Giant Magnetoresistive sensors (GMR) as wide band magnetic sensors to detect locally the NMR signal. GMR sensors and NMR set up have been specifically designed to have a detectivity in the range of 20pt/sqrt(Hz) and able to work with external magnetic field up to 1T. We will first present the results obtained at 0.3T on water, in the configuration where the local NMR is done on a high volume, highlighting the functionality of the set-up. Then we will show the results obtained also at 0.3T, of NMR spectroscopy of model liquids like Ethanol on a volume of the order of 20x20x20μm³. Finally, a result at a higher magnetic field, 0.6T, has also been obtained on water
13
Clarke, William. "Human cardiac magnetic resonance spectroscopy." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b75351dc-e4eb-4856-b901-4ba486ffe175.
Анотація:
The status of the myocardial 'high energy phosphate' metabolism is a sensitive marker of the occurrence and progression of heart failure. Magnetic resonance spectroscopy enables non-invasive, direct and potentially quantitative measurements of the phosphate containing metabolites present in the human myocardium. This thesis is primarily concerned with the creation of measurement techniques for cardiac phosphorus magnetic resonance spectroscopy (31P-MRS) at the 7 tesla field strength. Chapter 1 provides an overview of the physical basis of magnetic resonance spectroscopy, the myocardial high energy phosphate metabolism, and the clinical relevance of the technique. Chapter 2 describes the advantage of 7 tesla scanners over lower field strengths. The radio frequency coil hardware is characterised experimentally. The multivoxel spectroscopy methods used throughout the thesis are described. Chapter 3 details the implementation of an open source spectroscopy fitting program. It is validated against previous closed-source implementations. The program's use is demonstrated in several clinical studies of heart failure, and to improve a previously implemented 1H spectroscopy coil combination method. In Chapter 4 the measurement of inorganic phosphate in the presence of overlapping peaks is attempted. Suppression of overlapping peaks, originating from the blood, is tried using Bo gradients, then saturation transfer. The myocardial pH of hypertrophic cardiomyopathy patients is measured. Chapter 5 describes the effect of creatine kinase catalysed chemical exchange on the 31P-MRS spectrum. A survey of methods suitable for measuring creatine kinase kinetics at 7 tesla is made. Multi-parametric fitting of variable repetition time saturation transfer data is explored in simulation and experiment. Chapter 6 describes the re-implementation and extension, for dynamic measurements, of the triple repetition time saturation transfer method for two clinical studies at 3 tesla. The creatine kinase forward rate constant is measured in heart failure and healthy cohorts, at rest, and during cardiac stress. In Chapter 7 a Bloch-Siegert B1 mapping sequence is implemented for 31P-MRS. An optimal Bloch-Siegert method for X-nuclear spectroscopy is calculated. B1maps are validated in skeletal muscle and collected in 5 volunteer's hearts. Chapter 8 uses the Bloch-Siegert B1 mapping sequence and the four angle saturation transfer method to implement creatine kinase rate measurement at 7 tesla. The first 3D localised creatine kinase rate measurements in the human myocardium are achieved in 10 volunteers.
14
Borisov, Alexey S., and University of Lethbridge Faculty of Arts and Science. "Solid-state nuclear magnetic resonance spectroscopy of phosphazene polymers." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, c2009, 2009. http://hdl.handle.net/10133/1305.
Анотація:
High-resolution one-dimensional 1H, 19F, 31P and 13C MAS NMR experiments
were used in a morphological study of solvent-cast and heat-treated
poly[bis(trifluoroethoxy)phosphazene] (PBFP). Deconvolution analyses performed on all
Nuclear Magnetic Resonance (NMR) spectra are presented. These results suggest the
presence of broad and narrow overlapping components at ambient temperature, which
were assigned to the crystalline, amorphous and the mesophase regions within the
polymer, respectively. The number of signals in the spectra was independently verified
using 1H, 19F and 13C Discrimination Induced by Variable Amplitude Minipulses
(DIVAM) nutation experiments. Deconvolution analyses showed that heat-treatment
increases the overall crystallinity of the solvent-cast PBFP. Further studies conducted on
two preparations of the polymer showed significant differences in crystallinity due to
variations in the reaction conditions. Magic-Angle Spinning (MAS) NMR spectra of
PBFP obtained via living cationic polymerization at ambient temperature indicated that
the polymer contains mostly amorphous and mesophase regions with only a small
contribution from the crystalline domain.
Variable-temperature 31P NMR experiments suggested that the thermotropic
transition occurs in a temperature range of 80ºC to 90ºC, where the crystalline signal
disappears and a new signal due to a liquid crystalline phase emerges. Spin-lock 31P
experiments provided rates of the transverse relaxation in the rotating frame for each
signal, showing that the crystalline and the amorphous regions within the polymer are
characterized by significantly different mobilities at ambient temperatures, while the
v
comparable degree of motion occurs between the amorphous and mesophase
environments at temperatures above 90ºC.
The process of thermal ring-opening polymerization of
hexachlorocyclotriphosphazene was monitored using one-dimensional 31P MAS NMR at
different stages of the reaction. The ratio between cyclic species and the high molecular
weight poly(dichlorophosphazene) was seen to change over time. 31P NMR was seen to
be a potentially valuable tool in monitoring rates of chain propagation, branching and
cross-linking. Two-dimensional 31P homonuclear Radio-Frequency Driven Recoupling
(RFDR) and Incredible Natural Abundance Double Quantum Transfer (INADEQUATE)
MAS NMR experiments were first tested on the partially phenoxy-substituted
hexachlorocyclotriphosphazene, and subsequently applied in the study of a preparation of
the partially trifluoroethoxy-substituted poly(dichlorophosphazene). Very high resolution
was obtained in the direct dimension due to the presence of low molecular weight
species. Preliminary spectral assignments of all of the observed signals were made on the
basis of both known chemical shifts of the related species, and the through-space and
through-bond phosphorous-phosphorous connectivities.xiii, 188 leaves : ill. ; 29 cm
15
Friedrich, J. O. "Frequency and spatial selectivity in nuclear magnetic resonance spectroscopy." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234964.
16
Wijeyesekera, Anisha Dimanthi. "Nuclear magnetic resonance spectroscopy based metabolic profiling of ageing." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520984.
17
Stourton, E. C. "Anisotropic interactions in solid-state nuclear magnetic resonance spectroscopy." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243269.
18
Champion, de Crespigny Alexander James Stephen. "Spatial localisation in nuclear magnetic resonance imaging and spectroscopy." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386006.
19
Zhang, Yang 1964. "Radio frequency gradient high resolutions nuclear magnetic resonance spectroscopy." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39054.
20
Stonehouse, Jonathan. "New techniques in NMR spectroscopy." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360628.
21
Almond, Graham G. "A nuclear magnetic resonance study of hydrous layer silicates." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5096/.
Анотація:
This is a study of five silicates, namely makatite, kanemite, octosilicate, magadiite and kenyaite. The silicates have been analysed using a range of techniques, principally solid-state NMR spectroscopy. High-quality (^29)Si NMR spectra have been obtained for samples of all five layered sodium polysilicate hydrates. Amongst other findings, these have revealed four crystallographically distinct sites in makatite and a Q(^4):Q(^4) site ratio in kenyaite of ca. 5. Proton MAS NMR studies can produce well-resolved spectra, particularly for carefully-dried samples. Distinct water and strongly hydrogen-bonded proton species have been detected. The latter are particularly noteworthy and they are present in kanemite, octosilicate, magadiite and kenyaite, but not in makatite or layered silicic acids. Interactions between the resolved proton species have been investigated with a series of 1- and 2-dimensional experiments resulting in the detection of mixing, via spin-diffusion or chemical exchange. Sodium-23 NMR studies were complicated by second-order effects from strong quadrupolar interactions and the presence of a significant signal from a sodium chloride contamination in many samples. The latter had fooled previous authors. Acidification products of kanemite, octosilicate and magadiite were characterised by (^29)Si CP NMR, thermogravimetric analysis, 1H MAS NMR and powder X-ray diffraction. A single H-kanemite sample proved to be H(_2)Si(_2)O(_5), but two types of H-octosilicate and H-magadiite sample were prepared. These differed in the presence of interlayer water. Several CP experiments were used to investigate the relationship between (^29)Si and (^23)Na nuclei and protons in the silicates. Cross-polarisation mechanisms tended to involve magnetisation transfer from the H-bonded protons only. Their determination was possible with a consideration of the extent of spin-diffusion or chemical exchange over the time-scale of the relevant experiments. Finally, new model structures for kanemite and the interlayer space in kanemite, octosilicate, magadiite and kenyaite have been suggested, while previously- proposed silicate layers have been reconsidered.
22
Wang, Yue. "Investigations of RNA pseudoknot structures and dynamics by nuclear magnetic resonance spectroscopy /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992935.
23
Iannaccone, Gennaro A. "The development of laboratory sessions for a introductory course in nuclear magnetic resonance spectroscopy." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01202010-020241/.
24
Jones, Jonathan A. "Nuclear magnetic resonance data processing methods." Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:7df97c9a-4e65-4c10-83eb-dfaccfdccefe.
Анотація:
This thesis describes the application of a wide variety of data processing methods, in particular the Maximum Entropy Method (MEM), to data from Nuclear Magnetic Resonance (NMR) experiments. Chapter 1 provides a brief introduction to NMR and to data processing, which is developed in chapter 2. NMR is described in terms of the classical model due to Bloch, and the principles of conventional (Fourier transform) data processing developed. This is followed by a description of less conventional techniques. The MEM is derived on several grounds, and related to both Bayesian reasoning and Shannon information theory. Chapter 3 describes several methods of evaluating the quality of NMR spectra obtained by a variety of data processing techniques; the simple criterion of spectral appearance is shown to be completely unsatisfactory. A Monte Carlo method is described which allows several different techniques to be compared, and the relative advantages of Fourier transformation and the MEM are assessed. Chapter 4 describes in vivo NMR, particularly the application of the MEM to data from Phase Modulated Rotating Frame Imaging (PMRFI) experiments. In this case the conventional data processing is highly unsatisfactory, and MEM processing results in much clearer spectra. Chapter 5 describes the application of a range of techniques to the estimation and removal of splittings from NMR spectra. The various techniques are discussed using simple examples, and then applied to data from the amino acid iso-leucine. The thesis ends with five appendices which contain historical and philosophical notes, detailed calculations pertaining to PMRFI spectra, and a listing of the MEM computer program.
25
Talagala, Sardha Lalith. "Aspects of NMR imaging and in vivo spectroscopy." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27550.
Анотація:
The work described in this thesis deals mainly with aspects related to two- and three-dimensional NMR imaging.
A detailed discussion on frequency-selective excitation using amplitude modulated rf pulses in relation to slice selection in NMR imaging has been presented. This includes the analysis and implementation
of the method as well as illustrative experimental results.
Several radiofrequency probe designs suitable for high field NMR imaging have been experimentally evaluated and their modification and construction are also described. The comparative results obtained indicate the merits and demerits of different designs and provide necessary guidelines for selecting the most suitable design depending on the application.
Practical aspects of two- and three-dimensional imaging have been discussed and NMR images of several intact systems have been presented.
Experimental methods which enable slice selection in the presence of chemically shifted species and two-dimensional chemical shift resolved imaging have "been described and illustrated using phantoms. The use of three-dimensional chemical shift resolved imaging as a potential method to map the pH and temperature distribution within an object has also been demonstrated.
A preliminary investigation of the application of ³¹P NMR spectroscopy
to study the biochemical transformations of the rat kidney during periods of ischemia and reperfusion has been presented.Science, Faculty of
Chemistry, Department of
Graduate
26
Keevil, Stephen Frederick. "Experimental techniques to characterise localisation in nuclear magnetic resonance spectroscopy." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268303.
27
Bilinovich, Stephanie M. "Nuclear Magnetic Resonance Spectroscopy in the Study of Protein Complexes." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1396871078.
28
Chiu, Pui-wai, and 趙沛慧. "¹H and ³¹P brain magnetic resonance spectroscopy in aging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47170505.
Анотація:
Magnetic Resonance Spectroscopy (MRS) was used to study the relationship between brain regional concentrations of metabolites and normal aging in Chinese. Our goal in this study is to create a database of normal aging and hence enhance further understanding on the degenerative process leading to dementia and related neurodegenerative diseases.
Thirty cognitively normal healthy volunteers of age 22-82 years were recruited and the bias on gender effect in data sampling was minimized by recruiting 15 females and 15 males. In the first part of the study, 1H MRS was obtained using single-voxel-spectroscopy (SVS). Offline software java-based version of Magnetic Resonance User Interface (jMRUI) was employed for data analysis. Cerebrospinal fluid was normalized using software voxel based morphormetry (VBM). Brain morphometry data was also analyzed. Brain metabolites choline (Cho), creatine (Cr) and N-acetyl aspartate (NAA) were quantified using internal water as reference. It was found that brain metabolite concentrations of Cr, Cho and NAA increase significantly with age. Gender effect on metabolite concentrations were also discovered, being higher in the female group. For brain morphometry, white matter and grey matter volumes and fractions all reveal a siginificant negative correlation with age, whereas CSF volume and fraction show a significant positive correlation with age. Gender effect was found on grey matter, white matter and intracranial volume, being higher in the male group.
In the second part of the study, 31P SVS MRS was performed on the same population of volunteers. jMRUI was also employed for data analysis. Metabolic ratios were obtained. Similar to the 1H MRS study, apart from creating a database in studying normal aging, an additional aim of this 31P MRS study is to correlate with 1H MRS and assist in interpreting the corresponding metabolic activity. Brain metabolite concentrations were found to increase significantly with age. The increase of PCr (phosphocreatine)/Ptot (total phosphorus content) in posterior cingulate suggests lower metabolic activity throughout the course of aging. The strong evidence of PDE (phosphodiester) increase with age in left hippocampus proposes the fact that phospholipid membrane breakdown will be enhanced by aging.
In conclusion, MRS can act as a non-invasive tool to study aging at molecular level. Metabolite levels are significant means to investigate the metabolic change in the human brain during the process of aging as the variations in metabolite levels are believed to be footprints of biochemical changes.published_or_final_version
Diagnostic Radiology
Master
Master of Philosophy
29
Woodruff, Nicholas D. "Investigation of protein structure and folding by NMR spectroscopy." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302124.
30
Halse, Meghan Eileen. "Multi-acquisition and multi-dimensional Earth's field nuclear magnetic resonance spectroscopy : a thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy in Physics /." ResearchArchive@Victoria e-Thesis, 2009. http://hdl.handle.net/10063/1198.
31
Staudacher, Tobias [Verfasser]. "Nuclear magnetic resonance spectroscopy on a nanoscopic sample volume / Tobias Staudacher." München : Verlag Dr. Hut, 2015. http://d-nb.info/1071513168/34.
32
Edlich, Christian. "Structural studies of the pleckstrin protein by nuclear magnetic resonance spectroscopy." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973963123.
33
Lee, Sangwon. "Applications of nuclear magnetic resonance spectroscopy to membrane protein structure determination." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3258823.
Анотація:
Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed June 8, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 123-137).
34
Campbell, Susan Christina. "Pharmaceutical polymorphism : an investigation using solid-state nuclear magnetic resonance spectroscopy." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/5021/.
Анотація:
The study of two pharmaceutically active systems that each display polymorphism has provided a platform upon which to develop and apply solid-state NMR techniques in order to increase the understanding of the solid-state structure of small organic molecules. The multidisciplinary approach adopted has highlighted the advantages of solid-state NMR as a non-invasive probe of molecular conformation and crystallographic packing.Carbon-13 CP/MAS spectra of the two polymorphs of BRL55834 - a fluorinated benzopyran derivative - immediately suggest the presence of one and three molecules in the asymmetric unit. A lack of crystals suitable for single-crystal XRD has catalysed the application of high-power powder X-ray diffraction studies. Subsequent attempts at structure solution using Genetic Algorithm techniques are showing preliminary results that reinforce predictions made from solid-state NMR. Novel triple-channel techniques have aided assignment and resolution of die complex (^13)C CP/MAS spectra. Enrichment of the (^15)N site appears to have resulted in the formation of a new polymorph. Techniques for the analysis of detection Units have been developed using solid-state Raman spectroscopy and chemometric analysis. The aminoxanthine derivative, BRL61063, provides interesting inter-form variations in molecular disorder, solid-state packing, and hydrogen bonding. A previously basic understanding of the single-crystal XRD data has been further evaluated through the course of this Ph.D. and solid-state NMR spectral editing techniques have been developed and applied to identify these phenomena. Recrystallisation studies have produced two samples that appear to exist in an intermediate state between the rigid and mobile structural limits. Temperature variation causes interesting changes in the relaxation characteristics and natural abundance (^15)N and (^13)C CP/MAS spectra. Residual dipolar coupling effects vary in their manifestation within the (^13)C CP/MAS spectra of the polymorphic systems studied and comparison with the literature yields important information regarding molecular conformation. Nitrogen-15 enrichment and operation at higher magnetic field have been applied to reduce these second order effects. Finally, some distance has been travelled along the path towards decoupling (^14)N. Future development of this technique holds potential for resolution enhancement in the solid state spectra of most naturally occurring, nitrogen-containing molecules.
35
Wasim, Mohammad. "Application of chemometrics to liquid chromatography with nuclear magnetic resonance spectroscopy." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412363.
36
Yao, Hongyang. "Microstructures of poly(vinyl acetate) studied by nuclear magnetic resonance spectroscopy." W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539623911.
Анотація:
Carbon-13 NMR spectroscopy was used to investigate the microstructures of poly(vinyl acetate) prepared by solution polymerization in benzene. A series of aromatic compounds was synthesized in order to model the structures formed via chain transfer to solvent. The peaks near 126.5 and 128.5 ppm in the spectra of the polymer samples were assigned to a 1-phenyl-(2n + 1)-multi-acetoxyalkane (where n = 1, 2, 3, etc.) microstructure. The concentration of that structure obtained from NMR spectra was correlated with the concentration calculated from reported kinetic data.;Chain transfer to benzene was shown to occur by addition of the macroradical to benzene, followed by rearomatization involving loss of a hydrogen atom. No evidence was obtained for a transfer mechanism involving hydrogen abstraction from benzene, and the copolymerization of benzene with vinyl acetate also was shown to be absent. The transfer mechanism actually established accounts for the unexpectedly large transfer constant of benzene in vinyl acetate polymerization. General mechanisms are proposed for the solution polymerization of vinyl acetate in aromatic solvents.
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Chong, Geokmei. "Nuclear magnetic resonance spectroscopy based metabolomics of breast cancer in hypoxia." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6198/.
Анотація:
Hypoxia has emerged as a crucial part of the aetiology of tumours. It is a negative prognostic factor which is associated to chemoresistance, invasiveness and metastasis. There is a strong association between hypoxia and metabolic transformation in breast cancer due to the alterations of multiple metabolic pathways. However, the current understanding of the nature of metabolic alterations in hypoxia is insufficient. This thesis uses NMR as a tool to investigate both the static metabolome by measuring metabolite concentrations, as well as to determine \(^1\)\(^3\)C metabolic fluxes using stable isotope tracers to reveal metabolic pathway alterations by hypoxia in vitro and by tumour growth in vivo. Firstly, we developed the \(^1\)\(^3\)C isotopomer distribution (CID) analysis to quantify metabolic fluxes by following the evolution of specific isotopomers of specific pathways of interests. MCF7 breast cancer cells were analysed in hypoxia using an integrated approach using gene expression, steady-state metabolite levels and \(^1\)\(^3\)C metabolic flux analysis to pinpoint hypoxia induced metabolic alterations. These most significant alterations were an up-regulation of the pentose phosphate pathway and a down-regulation of mitochondrial oxidative metabolism by lowering the PDH flux. The latter was partially compensated by carbon entry into the mitochondria by increasing flux through pyruvate carboxylase (PC). Further attention was focused towards identifying the shifts in metabolic activity in PC altered cells using [1,2-\(^1\)\(^3\)C]glucose and [3-\(^1\)\(^3\)C]glutamine as precursor nutrients correlated to cellular transformation potential accessed by cell viability. Finally, the \(^1\)\(^3\)C labelled glucose strategy was applied to a cancer model in mice model by infusing mice with [1,2-\(^1\)\(^3\)C]glucose. \(^1\)\(^3\)C glucose administration protocol was optimised in order to enable an investigation of \(^1\)\(^3\)C metabolic fluxes in tumour tissue to identify metabolic pathway differences between earlier stage and advanced stage of mammary gland tumours. In conclusion, an NMR based metabolomics analysis is suitable for discovering metabolic pathway alterations using both in vitro and in vivo models.
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Bennett, Andrew E. (Andrew Ernest). "Dipolar recoupling and decoupling in solid state nuclear magnetic resonance spectroscopy." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37016.
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Itin, Boris. "Structure and dynamics studies by solid-state nuclear magnetic resonance spectroscopy." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8051.
Анотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2002.Vita.
Includes bibliographical references.
The major goal of this work is the development of high resolution solid state 205T1 NMR techniques and their application to the elucidation of the mechanism and dynamics of ion exchange in biological solids. The thesis starts with a review of recent progress in solid state NMR spectroscopy. The importance of directly observing ions in biological systems is discussed, and the advantages of 205T1 spectroscopy are noted of. Theoretical framework of the NMR experiments is described in chapter 2. The third chapter presents the development of methodology for solid state 205T1 NMR. The difficulties of 205T1 NMR are identified, and ways to circumvent the limitations are discussed. Several model compounds convenient for calibration of the key experimental parameters are discussed. The 205T1 direct excitation and H-205T1 cross polarization experiments are demonstrated. The fourth chapter describes the application of 205T1 high resolution solid state NMR to the investigation of the behavior of a small ion channel in the liquid crystalline phase. Here, thallium binding to gramicidin A in DMPC bilayers has been studied. Additional applications of 205T1 NMR to study liquid crystalline phases are also discussed. A summary and the future directions of the 205T1 NMR spectroscopy are presented in chapter 5.
(cont.) The sixth chapter describes a 129Xe-19F high resolution solid state NMR study of crystalline XeF2. The absence of trapped Xe gas in crystalline XeF2 has been demonstrated. The 129Xe chemical shift anisotropy parameters have been extracted, and 19F-129Xe J-coupling has been measured. Progress in NMR spectroscopy is largely dependent on the capabilities and limitations of the experimental hardware. Chapter 7 presents a brief review of the development of probes for solid state NMR experiments. A triple channel H-13C-15N transmission line probe designed and constructed by the author is described.
by Boris Arkadievich Itin.
Ph.D.
40
Morris, Daniel L. "NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY IN THE STUDY OF PROTEIN-LIGAND INTERACTIONS." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1524681449524557.
41
Maus, Douglas C. (Douglas Charles). "Molecular and spin dynamics in solid state nuclear magnetic resonance spectroscopy." Thesis, Massachusetts Institute of Technology, 1996.
Анотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Dept. of Chemistry, 1996Cataloged from PDF of thesis. Microfiche contains the reproduction of the print thesis.
Includes bibliographical references (page 152).
Nuclear Magnetic Resonance (NMR) spectroscopic data often involve spatial and spin dynamics and interference phenomena between the two. Experimental results are presented which demonstrate several of these phenomena and exploitation of these anomalies to acquire and improve knowledge regarding relevant chemistry. In some cases numerical analysis of such data are illustrated for obtaining quantitative rates of molecular dynamics. First, the dynamics of methyls bonded to the metals Tungsten and Tantalum are examined. In the case of Tungsten. an interference between methyl dynamics and proton decoupling is studied, whereas in the Tantalum instance, interference between molecular dynamics and Magic Angle Spinning (MAS) is examined. Agostic interactions had been hypothesized to exist in both compounds, but the unusual molecular dynamics are explainable without invoking a relation to such interactions. Further, no evidence is found to support the existence agostic bonds from examination of X-ray crystal data. Next. the spin dynamics in high resolution solid state proton systems diluted by deuterium is examined. In this case techniques such as Rotational Resonance and Radio-Frequency driven Dipolar Recoupling (RFDR) are employed to counteract the averaging of dipole couplings induced by MAS. The numerical analysis of such data in systems in which internuclear distances of interest are not identical but rather statistically distributed is discussed. Finally, a technique which may improve the sensitivity of NMR experiments is demonstrated. Dynamic Nuclear Polarization (DNP) is adapted to solid state MAS experiments and shown to enhance the signal intensity of a biomolecule, T4-lysozyme, by a factor of ~50. The necessary conditions for application of this technique to solid state NMR is discussed.
by Douglas C. Maus.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Dept. of Chemistry
42
Goodwin, Matthew Ian. "Towards high-throughput fragment screening by microlitre nuclear magnetic resonance spectroscopy." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.723484.
43
Krishnan, Mangala Sunder. "Applications of irreducible spherical tensor operators to NMR and NQR spectroscopy." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75771.
Анотація:
The thesis extends the concept of Irreducible Spherical Tensor Operators to spin dynamics problems in Nuclear Magnetic and Quadrupole Resonance Spectroscopy. NQR and solid state NMR deal with spin systems which behave as effective single spins in many, pulsed experiments, or as multispin systems when the dipolar interactions among spins cannot be neglected. The thesis considers problems in both areas. New analytic results are derived in the thesis for pure NQR spectroscopy and for the effect of radiofrequency fields in the presence of electric quadrupolar interaction. Three-pulse experiments are proposed for a spin-5/2 system and quantitative calculations are done for the indirect detection of new observables. Attention is focussed on the usefulness of the full-spin density matrix in all these calculations. In addition the concept of multispin tensors is applied to a system of spin-1/2 nuclei with strong dipolar interactions. This leads to coupled differential equations for correlations among spins for which an iterative solution can be obtained. The solutions are discussed in relation to Free Induction Decay experiments available for $ sp{19}$F nuclei in CaF$ sb2$ crystal.
44
Barrett, Tina Alexandra. "Experimental considerations for the development of a nuclear magnetic resonance force microscope /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
45
Schachter, Joyce. "Application of surface coils to in-vivo studies using ³¹P-NMR spectroscopy." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24914.
Анотація:
The work described in this thesis is divided into two parts: testing and evaluation of some surface coils, and application of the surface coils to in-vivo studies. In particular, the localization properties of surface coils were examined and optimized using the highest performance coil geometry and wire. Application of the surface coil technique to in-vivo studies involved measuring changes in metabolic status of muscle and brain tissue in rats using ³¹P spectroscopy.
The properties of surface coils have been studied by evaluating their excitation patterns with ¹H and ³¹P NMR spectroscopy. Surface coils, manufactured in different sizes, geometries, and materials were tested for Q factors, signal-to-noise ratios, and pulse widths required for excitation of the sample. A silver plating on the copper wire used to fabricate the surface coils was found to increase the Q and signal-to-noise of the coil. Examination of the excitation patterns of the surface coils with point samples characterized the B₁ field of the coils as decreasing axially and radially from the coil. Calculations of the magnitude of the B₁ field reveal that its dome-like shape extends to approximately one coil radius above the surface coil. It was found that samples lying outside the domain of this "sensitive volume" did not contribute to a spectrum. These data were all correlated and the "0.9" silver plated coil was deemed to be the most efficient coil with which to pursue further in-vivo studies.
In-vivo ³¹P studies of rat tissues were preceded by in-vitro spectral measurements of various metabolites at physiological concentrations. These standards were used to aid in the identification of resonances in the in-vivo spectra. Metabolic changes such as artificially induced ischemia in muscle, deceased brain, and artificially induced brain dementia were compared with "normal" ³¹P spectra of anaesthetized rat tissues. It was found that oxygen deprivation is readily observed with this technique whereas the preparation of brain dementia cannot be diagnosed with ³¹P NMR spectroscopy.Science, Faculty of
Chemistry, Department of
Graduate
46
Yang, Yinhua. "Application of biomolecular NMR spectroscopy for protein structure determination." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42182013.
47
Marsih, I. Nyoman. "A mechanistic study of the Fischer-Tropsch reaction by '1'3C NMR spectroscopy." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370074.
48
Eyles, Stephen J. "Studies of protein folding by NMR spectroscopy." Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:06b8fb16-790c-4b72-80d0-8317920655fe.
Анотація:
This thesis describes an investigation of the folding and stability of a series of derivatives of the proteins lysozyme and α-lactalbumin which lack one or more of their four native disulphide bridges. Removal of the disulphide bridge which links the N- and C-termini from hen lysozyme results in a three-disulphide derivative (CM6,127-lysozyme). This has a profound effect on its stability against thermal denaturation, the Tm for unfolding being reduced by 25°C at pH 3.8. Calorimetric measurements performed on this three-disulphide derivative indicate that this reduction in stability may be attributed entirely to an increase in the entropy difference between the native and denatured states. Kinetic refolding studies of CM6,127-lysozyme using stopped flow optical methods and hydrogen exchange pulse labelling in conjunction with NMR and electrospray ionisation mass spectrometry (ESI-MS) suggest that this reduced stability manifests itself primarily in the α-domain of the protein. A transient intermediate populated during refolding of the unmodified protein can no longer be detected during folding of the derivative resulting in highly cooperative folding under the conditions investigated. The structure and stability of a three- and two-disulphide derivative of the homologous protein, α-lactalbumin have been investigated by NMR spectroscopy. The three-disulphide species, like its lysozyme counterpart, can adopt native structure but this is much more unstable than the intact protein. Removal of a second disulphide bridge, however, destabilises α-lactalbumin to the extent that the native state is no longer formed. Instead, in the presence of Ca2+ and high concentrations of salt, a partially structured state is induced which has some elements of tertiary structure present. Novel techniques of ESI-MS have been developed to study protein folding and stability using hydrogen exchange techniques. Applications to the investigation of cooperativity in protein folding, stability in native, partially folded and unfolded states, and the interactions of a partially folded protein with the chaperone GroEL are described.
49
Mingione, Velia. "Characterization of carotenoid pigments in Atlantic salmon using Nuclear Magnetic Resonance spectroscopy." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Анотація:
La Norvegia è il leader mondiale per la produzione di salmone dell’Atlantico (Salmo salar). Il salmone norvegese è la specie più commercializzata in Europa e la terza specie ittica più consumata nel mondo (EUMOFA, 2016).
La qualità del pesce è un concetto complesso che coinvolge diversi fattori come sicurezza, qualità nutrizionale, disponibilità, convenienza e altri attributi come colore e freschezza (Botta, 1995; Cardello, 1995).
La pigmentazione muscolare nei salmonidi d'allevamento è considerata il parametro di qualità più importante dopo la freschezza (García-Chavarría et al., 2013).
Studi sul comportamento del consumatore hanno dimostrato che la colorazione di questo prodotto viene inconsciamente relazionata con valore nutritivo, salubrità, freschezza e gusto. Difatti, al momento dell’acquisto, i consumatori hanno affermato che il colore è un parametro molto influente e sono disposti a pagare di più per un salmone più “rosso” (Anderson, 2000; García-Chavarría et al., 2013).
La tipica colorazione rosata che caratterizza i salmonidi è dovuta ai carotenoidi (Shahidi et al., 1998). L’alimentazione con questi pigmenti è considerata la pratica di allevamento più importante per il salmone (Moe, 1990). Per questo motivo, ci sono diversi studi al riguardo.
Lo scopo di questa tesi è sviluppare una metodologia per estrarre ed analizzare i principali carotenoidi presenti nel tessuto muscolare e negli organi dei salmonidi, tramite l’utilizzo della Risonanza Magnetica Nucleare ad alta risoluzione (HR 1H-NMR).
50
Potwarka, John J. "A proton decoupled phosphorus-31 nuclear magnetic resonance spectroscopy study of schizophrenia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0019/MQ58006.pdf.