Dissolved organic matter (DOM) is comprised of a complex array of molecular constituents that are linked to many globally-relevant processes and yet this material is still largely molecularly uncharacterized. Research presented here attempted to probe the molecular complexity of this material from both Arctic and temperate climates via multifaceted and novel approaches. DOM collected from remote Arctic watersheds provided evidence to suggest that permafrost-disturbed systems contain more photochemically- and biologically-labile material than undisturbed systems. These results have large implications for predicted increasing temperatures where widespread permafrost melt would significantly impact stores of organic carbon in polar environments. In attempting to address the complexities and reactivity of DOM within global environments, more information at the molecular-level is necessary. Further research sought to unravel the molecularly uncharacterized fraction via use of nuclear magnetic resonance (NMR) spectroscopy in conjunction with hyphenated and varied analytical techniques. Directly hyphenated high performance size exclusion chromatography (HPSEC) with NMR was explored. This hyphenation was found to separate DOM into structurally distinct fractions but proved limited at reducing DOM heterogeneity. Of the many high performance liquid chromatography (HPLC) techniques tested, hydrophilic interaction chromatography (HILIC) was found the most effective at simplifying DOM. HILIC separations utilizing a sample from Florida resulted in fractions with highly resolved NMR signals and substantial reduction in heterogeneity. Further development with a 2D-HILIC/HILIC system to achieve additional fractionation was employed. This method produced fractions of DOM that were homogenous enough to produce excellent resolution and spectral dispersion, permitting 2D and 3D NMR experiments to be performed. Extensive NMR analyses of these fractions demonstrated strong evidence for the presence of highly oxidized sterols. All fractions, however, provided 2D NMR spectra consistent with oxidized polycyclic structures and support emerging data and hypotheses suggesting that cyclic structures, likely derived from terpenoids, are an abundant, refractory and major component of DOM. Research presented within this thesis demonstrates that HILIC and NMR are excellent co-techniques for the analysis of DOM as well as that oxidized sterols and other cyclic components with significant hydroxyl and carboxyl substituents are major constituents in DOM.

Small molecule mediated chemical intervention of biological processes using nucleic acid targets has proven extremely successful and is continually providing exciting new avenues for the development of anti-cancer agents and molecular probes. Among the alternative DNA confrormations, G-quadruplexes has certainly garnered much recognition due to increase in evidences supporting their involvement in diverse biological process. The grooves of the quadruplexes offer an alternate recognition site for ligand interactions with potentially higher selectivity than the traditional terminal stacking sites. DB832, a bifuryl-phenyl diamidine, was recently reported to selectively recognize human telomeric G-quadruplex, as a stacked species, with significant selectivity over duplex sequences. A series of biophysical studies were conducted to test the groove-binding mode of DB832, along with the selectivity for diverse quadruplex forming sequences. To gain better understanding of quadruplex groove-recognition by DB832, a series of structurally similar heterocyclic diamidines were also evaluated. The unique binding mode of DB832 may allow it to serve as a paradigm for the design of new class of highly selective quadruplex groove-binding molecules. Beyond the alternative secondary structures, it is also becoming increasingly apparent that the structure and dynamics of the canonical Watson–Crick DNA double helix play pivotal roles in diverse biological functions. DB1878, a phenyl-furan-indole diamidine, was shown to recognize a mixed GC/AT motif as a stacked antiparallel dimer, and a detailed structural analysis is reported here. Interestingly, the DNA recognition is completely different from the reported molecules in literature, and represents an entirely new motif for DNA minor groove recognition.

When increasing magnetic resonance imaging (MRI) resolution into the micron scale, image signal-to-noise ratio (SNR) can be maintained by using small radiofrequency (RF) coils in close proximity to the sample being imaged. Micro-scale RF coils (microcoils) can be easily fabricated on chip and placed adjacent to a sample under test. However, the high series resistance of microcoils limits the SNR due to the thermal noise generated in the copper. Cryo-cooling is a potential technique to reduce thermal noise in microcoils, thereby recovering SNR. In this research, copper microcoils of two different geometries have been cryo-cooled using liquid nitrogen. Quality-factor (Q) measurements have been taken to quantify the reduction in resistance due to cryo-cooling. Image SNR has been compared between identical coils at room temperature and liquid nitrogen temperature. The relationship between the drop in series resistance and the increase in image SNR has been analyzed, and these measurements compared to theory. While cryo-cooling can bring about dramatic increases in SNR, the extremely low temperature of liquid nitrogen is incompatible with living tissue. In general, the useful imaging region of a coil is approximately as deep as the coil diameter, thus cryo-cooling of coils has been limited in the past to larger coils, such that the thickness of a conventional cryostat does not put the sample outside of the optimal imaging region. This research utilizes a scheme of microfluidic cooling (developed in the Texas A&M NanoBio Systems Lab), which greatly reduces the volume of liquid nitrogen required to cryo-cool the coil. Along with a small gas phase nitrogen gap, this eliminates the need for a bulky cryostat. This thesis includes a review of the existing literature on cryo-cooled coils for MRI, as well as a review of planar pair coils and spiral microcoils in MR applications. Our methods of fabricating and testing these coils are described, and the results explained and analyzed. An image SNR improvement factor of 1.47 was achieved after cryo-cooling of a single planar pair coil, and an improvement factor of 4 was achieved with spiral microcoils.

Nuclear magnetic resonance (NMR) spectroscopy is capable to deliver a detailed information about the dynamics on molecular level in a wide range of time scales, especially if accompanied by suitably chosen theoretical tools. In this work, we employed a set of high-resolution NMR techniques to investigate dynamics processes in several weakly interacting molecular systems in solution. Van der Waals interactions play an important role in inclusion complexes of cryptophane-C with chloroform or dichloromethane. The complex formation was thoroughly investigated by means of 1H and 13C NMR experiments along with the quantum-chemical density functional theory (DFT) calculations. We characterized kinetics, thermodynamics, as well as fine details of structural rearrangements of the complex formation. Internal dynamics of oligo- and polysaccharides presents a considerable challenge due to possible coupling of internal and global molecular motions. Two small oligosaccharides were investigated as test cases for a newly developed integrated approach for interpreting the dynamics of the molecules with non-trivial internal flexibility. The approach comprised advanced theoretical tools, including stochastic modeling, molecular dynamics (MD) simulations, and hydrodynamic simulations. A biologically important bacterial O-antigenic polysaccharide from E. Coli O91 was addressed employing selective isotope labeling and multiple-field 13C relaxation experiments. The complex dynamics of the polysaccharide is characterized by the conformational motion of the exocyclic groups of the sugars, superimposed to the breathing motion of the polymeric chain. Hydrogen bonding is another major non-covalent interaction. Dilute solutions of ethanol were chosen as a model of liquid systems containing extensive hydrogen-bonded networks. We developed a new methodology consisting of NMR diffusion measurements, DFT calculations, and hydrodynamic modeling and utilized it to determine average size of the molecular clusters of ethanol at given conditions. / Nukleární magnetická rezonance (NMR) dokáže poskytnout detailní informace o dynamice na molekulární úrovni v širokém oboru časových škál, zejména pokud je doplněna vhodnými teoretickými nástroji. V této práci byla použita sada technik NMR spektroskopie vysokého rozlišení pro výzkum dynamických procesů slabě interagujících molekulárních struktur v roztoku. Van der Waalsovy interakce hrají důležitou roli v inkluzních komplexech kryptofanu-C s chloroformem nebo dichlormethanem. Tvorba komplexu byla podrobně zkoumána za použití 1H a13C NMR experimentů spolu s kvantově-chemickými výpočty. Byla charakterizována kinetika, termodynamika, jakož i detaily strukturních změn při tvorbě komplexu. Vnitřní dynamika oligo- a polysacharidů představuje velkou výzvu  kvůli možnému provázání lokálního a globálního molekulárního pohybu. Dva modelové oligosacharidy byly použity pro testování nově vyvinuté integrované metody pro popis dynamiky molekul s netriviální vnitřní flexibilitou. Tato metoda spojuje pokročilé teoretické výpočty včetně stochastického modelování, simulací molekulové dynamiky a hydrodynamiky. Antigenní bakteriální polysacharid z E. Coli O91, důležitý z biologického hlediska, byl studován za pomoci selektivního izotopového značení a NMR relaxačních experimentů ve více magnetických polích. Komplexní dynamika polysacharidu je charakterizována konformačními změnami exocyklických skupin cukerných reziduí a omezenou interní flexibilitou polymerního řetězce. Vodíkové vazby jsou další z důležitých nekovalentních interakcí. Zředěné roztoky ethanolu byly vybrány jako model kapalného systému obsahujícího rozsáhlou síť vodíkových vazeb. Vyvinuli jsme novou metodologii, složenou z NMR difúzních měření, kvantově-chemických výpočtů a hydrodynamického modelování a aplikovali ji pro zjištění průměrné velikosti molekulových klastrů ethanolu za specifických podmínek. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Accepted. Paper 5: Manuscript.</p>

Physical implementations of quantum computers will inevitably be subject to errors. However, provided that the error rate is below some threshold, it is theoretically possible to build fault tolerant quantum computers that are arbitrarily reliable. A particularly attractive fault tolerant proposal, due to its high threshold value, relies on Clifford group quantum computation and access to ancilla qubits. These ancilla qubits must be prepared in a particular state termed the 'magic' state. It is possible to distill faulty magic states into pure magic states, which is of significant interest for experimental work where perfect state preparation is generally not possible. This thesis describes a liquid state nuclear magnetic resonance based scheme for distilling magic states. Simulations are presented that indicate that such a distillation is feasible if a high level of experimental control is achieved. Preliminary experimental results are reported that outline the challenges that must be overcome to attain such precise control.

Quantum information processing has been the subject of countless discoveries since the early 1990's. It is believed to be the way of the future for computation: using quantum systems permits one to perform computation exponentially faster than on a regular classical computer. Unfortunately, quantum systems that not isolated do not behave well. They tend to lose their quantum nature due to the presence of the environment. If key information is known about the noise present in the system, methods such as quantum error correction have been developed in order to reduce the errors introduced by the environment during a given quantum computation. In order to harness the quantum world and implement the theoretical ideas of quantum information processing and quantum error correction, it is imperative to understand and quantify the noise present in the quantum processor and benchmark the quality of the control over the qubits. Usual techniques to estimate the noise or the control are based on quantum process tomography (QPT), which, unfortunately, demands an exponential amount of resources. This thesis presents work towards the characterization of noisy processes in an efficient manner. The protocols are developed from a purely abstract setting with no system-dependent variables. To circumvent the exponential nature of quantum process tomography, three different efficient protocols are proposed and experimentally verified. The first protocol uses the idea of quantum error correction to extract relevant parameters about a given noise model, namely the correlation between the dephasing of two qubits. Following that is a protocol using randomization and symmetrization to extract the probability that a given number of qubits are simultaneously corrupted in a quantum memory, regardless of the specifics of the error and which qubits are affected. Finally, a last protocol, still using randomization ideas, is developed to estimate the average fidelity per computational gates for single and multi qubit systems. Even though liquid state NMR is argued to be unsuitable for scalable quantum information processing, it remains the best test-bed system to experimentally implement, verify and develop protocols aimed at increasing the control over general quantum information processors. For this reason, all the protocols described in this thesis have been implemented in liquid state NMR, which then led to further development of control and analysis techniques.

Physical implementations of quantum computers will inevitably be subject to errors. However, provided that the error rate is below some threshold, it is theoretically possible to build fault tolerant quantum computers that are arbitrarily reliable. A particularly attractive fault tolerant proposal, due to its high threshold value, relies on Clifford group quantum computation and access to ancilla qubits. These ancilla qubits must be prepared in a particular state termed the 'magic' state. It is possible to distill faulty magic states into pure magic states, which is of significant interest for experimental work where perfect state preparation is generally not possible. This thesis describes a liquid state nuclear magnetic resonance based scheme for distilling magic states. Simulations are presented that indicate that such a distillation is feasible if a high level of experimental control is achieved. Preliminary experimental results are reported that outline the challenges that must be overcome to attain such precise control.

Quantum information processing has been the subject of countless discoveries since the early 1990's. It is believed to be the way of the future for computation: using quantum systems permits one to perform computation exponentially faster than on a regular classical computer. Unfortunately, quantum systems that not isolated do not behave well. They tend to lose their quantum nature due to the presence of the environment. If key information is known about the noise present in the system, methods such as quantum error correction have been developed in order to reduce the errors introduced by the environment during a given quantum computation. In order to harness the quantum world and implement the theoretical ideas of quantum information processing and quantum error correction, it is imperative to understand and quantify the noise present in the quantum processor and benchmark the quality of the control over the qubits. Usual techniques to estimate the noise or the control are based on quantum process tomography (QPT), which, unfortunately, demands an exponential amount of resources. This thesis presents work towards the characterization of noisy processes in an efficient manner. The protocols are developed from a purely abstract setting with no system-dependent variables. To circumvent the exponential nature of quantum process tomography, three different efficient protocols are proposed and experimentally verified. The first protocol uses the idea of quantum error correction to extract relevant parameters about a given noise model, namely the correlation between the dephasing of two qubits. Following that is a protocol using randomization and symmetrization to extract the probability that a given number of qubits are simultaneously corrupted in a quantum memory, regardless of the specifics of the error and which qubits are affected. Finally, a last protocol, still using randomization ideas, is developed to estimate the average fidelity per computational gates for single and multi qubit systems. Even though liquid state NMR is argued to be unsuitable for scalable quantum information processing, it remains the best test-bed system to experimentally implement, verify and develop protocols aimed at increasing the control over general quantum information processors. For this reason, all the protocols described in this thesis have been implemented in liquid state NMR, which then led to further development of control and analysis techniques.

Human thiopurine methyltransferase (TPMT) is an enzyme involved in the metabolism of thiopurine drugs, which are widely used in leukemia and inflammatory bowel diseases such as ulcerative colitis and Crohn´s disease. Due to genetic polymorphisms, approximately 30 protein variants are present in the population, some of which have significantly lowered activity. TPMT *5 (Leu49Ser) is one of the protein variants with almost no activity. The mutation is positioned in the hydrophobic core of the protein, close to the active site. Hydrogen exchange rates measured with NMR spectroscopy for N-terminally truncated constructs of TPMT *5 and TPMT *1 (wild type) show that local stability and hydrogen bonding patterns are changed by the mutation Leu49Ser. Most residues exhibit faster exchange rates and a lower local stability in TPMT *5 in comparison with TPMT *1. Changes occur close to the active site but also throughout the entire protein. Calculated overall stability is similar for the two constructs, so the measured changes are due to local stability. Protein dynamics measured with NMR relaxation experiments show that both TPMT *5 and TPMT *1 are monomeric in solution. Millisecond dynamics exist in TPMT *1 but not in TPMT *5, even though a few residues exhibit a faster dynamic. Dynamics on nanosecond to picosecond time scale have changed but no clear trends are observable.

In this study a hybrid Pore Network (PN) model that simulates two-phase (water-oil) drainage and imbibition mechanisms is developed. The developed model produces Nuclear Magnetic Resonance (NMR) T2 relaxation times using correlations available in the literature. The developed PN was calibrated using experimental relative permeability data obtained for Berea Sandstone, Kuzey Marmara Limestone, Yenik&ouml / y Dolostone and Dolomitic Limestone core plugs. Pore network body and throat parameters were obtained from serial computerized tomography scans and thin section images. It was observed that pore body and throat sizes were not statistically correlated. It was also observed that the developed PN model can be used to model different displacement mechanisms. By using the synthetic data obtained from PN model, an Artificial Neural Network (ANN) model was developed and tested. It has been observed that the developed ANN tool can be used to estimate oil &ndash / water relative permeability data very well (with less than 0.05 mean square error) given a T2 signal. It was finally concluded that the developed tools can be used to obtain multiphase flow functions directly from an NMR well log such as Combinable Magnetic Resonance (CMR).