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Showing 1 to 20 of 21 for “"Overhauser effect"”.

  1. The feasibility of the use of Overhauser effect in a nuclear free precession magnetometer.

    Cooper, D. L.Monterey, CA; Naval Postgraduate School1959

    … possible solutions to the problem. By using the Overhauser effect, the population gain of favorable proton states may be obtained by exciting the electrons of the free radical ON(SO3)2—and then using the spin-spin coupling of energy to the proton of the aqueous solution. This will provide a large …

    nps Repository record

  2. New methods for dynamic nuclear polarization in insulating solids : the Overhauser effect and time domain techniques

    Can, Thach V. (Thach Van)Massachusetts Institute of Technology2017

    … that current DNP mechanisms, including the cross effect and solid effect, utilize continuous wave (CW) microwave irradiation, and scale unfavorably with B0. This has motivated us to develop new DNP methods that do not suffer from the same field dependences. Our first attempt resulted in the …

    mit Repository record

  3. Nuclear magnetic resonance studies of molecular interactions and structures

    Coupland, AndrewAston University1978

    … or deutero-chloroform has been added. The effect of the added polar molecule on the liquid structure has been studied using spin-lattice relaxation time, 1H chemical shift, and nuclear Overhauser effect measurements. The main purpose of the work has been to validate a model for molecular …

    aston Repository record

  4. High field dynamic nuclear polarization methods: Microwave sources and mechanisms

    Mardini, MichaelMassachusetts Institute of Technology2024

    … nitroxide-based biradicals exploiting the cross effect mechanism. In this thesis, I argue that this approach is not necessarily optimal and report progress towards arbitrary-waveform DNP, in the construction of a suitable solid-state microwave source, and the use of narrow-line monoradicals …

    mit Repository record

  5. NMR Applications in Soft Materials Science: Correlation of Structure, Dynamics, and Transport

    Chen, YingVirginia Tech2015

    … than cation relaxation. 2D ¹H-¹⁹F heteronuclear Overhauser effect spectroscopy (HOESY) and 1D ¹⁹F¹⁹F selective nuclear Overhauser effect (NOE) spectroscopy confirm our assumption of the formation of ion clusters at low water content in the ionomer. While we observe non-restricted diffusion …

    vt Repository record

  6. Coherent Dynamic Nuclear Polarization: Mechanistic Insights and Experimental Advances

    Ouyang, YifuMassachusetts Institute of Technology2025

    … DNP mechanisms, including a re-evaluation of the Overhauser effect in insulating solids and a foundational treatment of the chirped solid effect. We also identified a new transfer channel, termed Resonant Mixing, arising from interference effects under off-resonance driving. Building on these …

    mit Repository record

  7. Solid/liquid intermolecular transfer of dynamic nuclear polarization - enhanced flowing fluid ¹H NMR signals via immobilized spin labels

    Gitti, Rossitza KuzmanovaVirginia Polytechnic Institute and State University1988

    … The resulting ¹H DNP line shapes imply that both Overhauser effect and solid- state effect are effective mechanisms for the DNP enhancements. The results suggest that the relatively low magnitude of the enhancements can be attributed to the longer molecular correlation times of the solid/liquid …

    vt Repository record

  8. Probing regioselectivity in the Diels -Alder cycloadditions between *[60]fullerene and aryl substituted acenes

    Rainbolt, James Eric

    … NOESY (nuclear Overhauser effect spectroscopy) methods are especially useful for the discrimination of 5,12 and 6,11 cycloaddition regioisomers of 15 and 41-45, as well as select Diels-Alder cycloaddition regioisomers of 22. The Diels-Alder reactivities of …

    unh-thes Repository record

  9. Development of new methods in solid-state NMR

    Ball, Thomas JamesUniversity of Glasgow2008

    … 87Rb NMR of a wide range of solids. The nuclear Overhauser effect (NOE) is one of the most widely exploited phenomena in NMR and is now widely used for molecular structure determination in solution. NOEs in the solid state are rare and those to quadrupolar nuclei rarer still, this being due to …

    glasgow Repository record

  10. Exploring the Chemistry of Bis(azido)phosphine Chalcogenides and the Pursuit of Isolable Phosphinidene Chalcogenides

    Lortie, JohnThe University of Western Ontario2024

    … of species was analyzed by 31P-31P nuclear Overhauser effect spectroscopy (NOESY). Thermogravimetric analysis (TGA) provided insights into the thermal stability of these compounds. Density functional theory (DFT) suggested that the observed chemoselectivity was a result of energetically …

    uwo Repository record

  11. Structural And Mechanistic Elucidation Of The EF-hand In LETM1 Ca2+/H+ Antiporter Function

    Lin, Qi-TongThe University of Western Ontario2024

    … characterized isolated EF1 to probe the effects of Ca2+ binding and changes in pH and temperature on secondary, tertiary and quaternary structure, thermal stability and high-resolution structure. We discovered the LETM1 EF1 features weak (~mM) but specific Ca2+ binding affinity that is …

    uwo Repository record

  12. Re-evaluation of analytical chemistry techniques in studying DNA structures

    Vanloon, JesseBrock University2022

    … sequence) were used to study the conformational effects displayed by each type of oligonucleotide sequence. The structural changes adopted by DNA was examined using a variety of analytical techniques, such as: nuclear magnetic resonance imaging (NMR), differential scanning calorimetry (DSC), …

    brock Repository record

  13. Dynafold: A Dynamic Programming Approach to Protein Structure Calculation From Residual Dipolar Couplings

    Mukhopadhyay, Rishi

    … methods are based on the collection of nuclear overhauser effect (NOE) data. However, the set of proteins amenable to analysis by NOE-based methods and X-ray methods does not span the entire set of protein structures found in nature. In particular, transmembrane proteins, a large and important …

    south-carolina Repository record

  14. Novel Algorithms for Automated NMR Assignment and Protein Structure Determination

    Zeng, Jianyang2011

    … the assignment of chemical shifts and nuclear Overhauser effect (NOE) restraints from NMR spectra. The development of automated and efficient procedures for analyzing NMR data and assigning experimental restraints will thereby enable high-throughput protein structure determination and advance …

    duke Repository record

  15. Drug-cyclodextrin complexes: an approach to enhance the solubility and dissolution properties of poorly soluble drugs

    Rudrangi, Shashi Ravi SumanUniversity of Greenwich2015

    … properties of drugs. Specifically, the effectiveness of supercritical carbon dioxide processing for the preparation of solid drug-cyclodextrin inclusion complexes was investigated and compared to other preparation methods. Nitrate, besylate, sulfosalicylate dihydrate and maleate salts of …

    greenwich Repository record

  16. Modelling and validation of bacterial O-antigen conformations: ring puckering in Shigella flexneri 7a and 7b O-antigens as a case study

    Timol, ZaheerDepartment of Computer Science2024

    … β-D-GlcpNAc trisaccharides. 1H nuclear Overhauser effect spectroscopy experiments were used to calculate 1H-1H distances in S. flexneri 7a and 7b O-antigens. These experimentally derived distances match those calculated from the repeating unit simulations when a mix of 4C1 and boat/skew …

    cape-town Repository record

  17. Advances in Sensitivity and Resolution of Solid State Nuclear Magnetic Resonance and Dynamic Nuclear Polarization

    Golota, Natalie C.Massachusetts Institute of Technology2023

    … This thesis first describes the mechanism of Overhauser Effect (OE) sensitivity enhancements in insulating solids. We demonstrate the generation of strong positive OE with less than 200 mW of microwave power. We also employ selective deuteration to elucidate the role of individual …

    mit Repository record

  18. Linear, Branched and Crosslinked Polymers, Polyesters, Polyurethanes and Polymethacrylates Derived From Rotaxane Formation: Syntheses and Properties

    Gong, CaiguoVirginia Tech1999

    … as monomers or comonomers. Using these BG's effectively reduced or prevented dethreading and thus indeed increased threading efficiency (m/n, average number of cyclics per repeat unit). The study also brought about new evidences for the formation of the polyrotaxanes, i.e., the hydrolytic …

    vt Repository record

  19. Folding and aggregation of amyloid peptides

    Kittner, MadeleineUniversität Potsdam

    … caused by hydrophobic and electrostatic effects. In contrast to the transition towards fibril-like dimers the first step of aggregation is driven by entropy. Here, we compared structural and thermodynamic properties of the individual monomer, dimer and trimer ensembles to gain qualitative …

    potsdam-diss Repository record

  20. MRI and NMR Investigations of Transport in Soft Materials and Explorations of Electron-Nuclear Interactions for Liquid-State Dynamic Nuclear Polarization

    Wang, XiaolingVirginia Tech2015

    … polymer diffusion coefficients in solutions. The effective characterization of molecular weights of polyelectrolytes has been a general and growing problem for the polymer industry, with no clear solutions in sight. In this study, we obtained the molar masses (Mw) for two series of sulfonated …

    vt Repository record

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