Search

Your search keyword '"Blanchard, John"' showing total 1,167 results
Start Over Author "Blanchard, John"

Refine your results

more »

more »

more »

more »

more »
1,167 results on '"Blanchard, John"'

51. Solution‐state 2D NMR spectroscopy of mixtures hyperpolarized using optically polarized crystals

Author

Parker, Anna J., primary, Dey, Arnab, additional, Qureshi, Mohammed Usman, additional, Steiner, Jakob M., additional, Blanchard, John W., additional, Scheuer, Jochen, additional, Tomek, Nikolas, additional, Knecht, Stefan, additional, Josten, Felix, additional, Muller, Christoph, additional, Hautle, Patrick, additional, Schwartz, Ilai, additional, Giraudeau, Patrick, additional, Eichhorn, Tim, additional, and Dumez, Jean-Nicolas, additional

Published
2023
Full Text
View/download PDF

52. Parahydrogen‐Polarized [1‐13C]Pyruvate for Reliable and Fast Preclinical Metabolic Magnetic Resonance Imaging (Adv. Sci. 30/2023)

Author

Nagel, Luca, primary, Gierse, Martin, additional, Gottwald, Wolfgang, additional, Ahmadova, Zumrud, additional, Grashei, Martin, additional, Wolff, Pascal, additional, Josten, Felix, additional, Karaali, Senay, additional, Müller, Christoph A., additional, Lucas, Sebastian, additional, Scheuer, Jochen, additional, Müller, Christoph, additional, Blanchard, John, additional, Topping, Geoffrey J., additional, Wendlinger, Andre, additional, Setzer, Nadine, additional, Sühnel, Sandra, additional, Handwerker, Jonas, additional, Vassiliou, Christophoros, additional, van Heijster, Frits H.A., additional, Knecht, Stephan, additional, Keim, Michael, additional, Schilling, Franz, additional, and Schwartz, Ilai, additional

Published
2023
Full Text
View/download PDF

53. Long-lived heteronuclear spin-singlet states

Author

Emondts, Meike, Ledbetter, Micah. P., Pustelny, Szymon, Theis, Thomas, Patton, Brian, Blanchard, John W., Butler, Mark C., Budker, Dmitry, and Pines, Alexander

Subjects
Physics - Chemical Physics, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We report observation of long-lived spin-singlet states in a 13C-1H spin pair at zero magnetic field. In 13C-labeled formic acid, we observe spin-singlet lifetimes as long as 37 seconds, about a factor of three longer than the T1 lifetime of dipole polarization in the triplet state. We also observe that the lifetime of the singlet-triplet coherence, T2, is longer than T1. Moreover, we demonstrate that this singlet states formed by spins of a heteronucleus and a 1H nucleus, can exhibit longer lifetimes than the respective triplet states in systems consisting of more than two nuclear spins. Although long-lived homonuclear spin-singlet states have been extensively studied, this is the first experimental observation of analogous spin-singlets consisting of a heteronucleus and a proton., Comment: 5 pages, 4 figures

Published
2013

54. Stochastic fluctuations of bosonic dark matter

Author

Centers, Gary P., Blanchard, John W., Conrad, Jan, Figueroa, Nataniel L., Garcon, Antoine, Gramolin, Alexander V., Kimball, Derek F. Jackson, Lawson, Matthew, Pelssers, Bart, Smiga, Joseph A., Sushkov, Alexander O., Wickenbrock, Arne, Budker, Dmitry, and Derevianko, Andrei

Published
2021
Full Text
View/download PDF

55. Liquid-state nuclear spin comagnetometers

Author

Ledbetter, Micah, Pustelny, Szymon, Budker, Dmitry, Romalis, Michael, Blanchard, John, and Pines, Alexander

Subjects
Physics - Atomic Physics, Nuclear Experiment, Physics - Chemical Physics
Abstract

We discuss nuclear spin comagnetometers based on ultra-low-field nuclear magnetic resonance in mixtures of miscible solvents, each rich in a different nuclear spin. In one version thereof, Larmor precession of protons and ${\rm ^{19}F}$ nuclei in a mixture of thermally polarized pentane and hexafluorobenzene is monitored via a sensitive alkali-vapor magnetometer. We realize transverse relaxation times in excess of 20 s and suppression of magnetic field fluctuations by a factor of 3400. We estimate it should be possible to achieve single-shot sensitivity of about $5\times{\rm 10^{-9} Hz}$, or about $5\times 10^{-11} {\rm Hz}$ in $\approx 1$ day of integration. In a second version, spin precession of protons and ${\rm ^{129}Xe}$ nuclei in a mixture of pentane and hyperpolarized liquid xenon is monitored using superconducting quantum interference devices. Application to spin-gravity experiments, electric dipole moment experiments, and sensitive gyroscopes is discussed., Comment: 5 pages 5 figures

Published
2012
Full Text
View/download PDF

56. Near-zero-field nuclear magnetic resonance

Author

Ledbetter, Micah, Theis, Thomas, Blanchard, John, Ring, Hattie, Ganssle, Paul, Appelt, Stephan, Bluemich, Bernhard, Pines, Alex, and Budker, Dmitry

Subjects
Physics - Atomic Physics
Abstract

We investigate nuclear magnetic resonance (NMR) in near-zero-field, where the Zeeman interaction can be treated as a perturbation to the electron mediated scalar interaction (J-coupling). This is in stark contrast to the high field case, where heteronuclear J-couplings are normally treated as a small perturbation. We show that the presence of very small magnetic fields results in splitting of the zero-field NMR lines, imparting considerable additional information to the pure zero-field spectra. Experimental results are in good agreement with first-order perturbation theory and with full numerical simulation when perturbation theory breaks down. We present simple rules for understanding the splitting patterns in near-zero-field NMR, which can be applied to molecules with non-trivial spectra., Comment: 5 pages, 5 figures

Published
2011
Full Text
View/download PDF

57. Fast Shimming Algorithm Based on Bayesian Optimization for Magnetic Resonance Based Dark Matter Search.

Author

Walter, Julian, Bekker, Hendrik, Blanchard, John, Budker, Dmitry, Figueroa, Nataniel L., Wickenbrock, Arne, Zhang, Yuzhe, and Zhou, Pengyu

Subjects
DARK matter, MAGNETIC resonance, MAGNETIC fields, ALGORITHMS, NUCLEAR magnetic resonance
Abstract

The sensitivity and accessible mass range of magnetic resonance searches for axion‐like dark matter depend on the homogeneity of applied magnetic fields. Optimizing homogeneity through shimming requires exploring a large parameter space, which can be prohibitively time consuming. The process of tuning the shim‐coil currents has been automated by employing an algorithm based on Bayesian optimization. This method is especially suited for applications where the duration of a single optimization step prohibits exploring the parameter space extensively or when there is no prior information on the optimal operation point. Using the cosmic axion spin precession experiment‐gradient low‐field apparatus, it is shown that for the setup this method converges after ≈30 iterations to a sub‐10 parts‐per‐million field homogeneity, which is desirable for our dark matter search. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

60. Checklists for Learning: When, Why and How to Pay Attention

Author

Blanchard, John

Abstract

This article gives an overview of the author's book "Inside Teaching: how to make a difference for every learner and teacher" (Routledge, 2017), and focuses on how checklist processes can be used to help clarify and guide purposes and ways of working. The intention is to be systematic and explicit without being bureaucratic and moribund. Effective decisionmaking in learning and teaching is seen to be associated with choosing when and how to pay attention to what matters most. Underpinning the discussion is a twin assumption: teachers also learn and learners teach. What applies to learners usually applies to teachers too, and vice versa.

Published
2017
Full Text
View/download PDF

62. Parahydrogen-Polarized [1-13C]Pyruvate For Reliable and Fast Preclinical Metabolic Magnetic Resonance Imaging

Author

Nagel, Luca, primary, Gierse, Martin, additional, Gottwald, Wolfgang, additional, Ahmadova, Zumrud, additional, Grashei, Martin, additional, Wolff, Pascal, additional, Josten, Felix, additional, Karaali, Senay, additional, Müller, Christoph A., additional, Lucas, Sebastian, additional, Scheuer, Jochen, additional, Müller, Christoph, additional, Blanchard, John, additional, Topping, Geoffrey J., additional, Wendlinger, Andre, additional, Setzer, Nadine, additional, Sühnel, Sandra, additional, Handwerker, Jonas, additional, Vassiliou, Christophoros, additional, van Heijster, Frits H. A., additional, Knecht, Stephan, additional, Keim, Michael, additional, Schilling, Franz, additional, and Schwartz, Ilai, additional

Published
2023
Full Text
View/download PDF

66. Solution‐State 2D NMR Spectroscopy of Mixtures HyperpolarizedUsing Optically Polarized Crystals.

Author

Parker, Anna J., Dey, Arnab, Usman Qureshi, Mohammad, Steiner, Jakob M., Blanchard, John W., Scheuer, Jochen, Tomek, Nikolas, Knecht, Stephan, Josten, Felix, Müller, Christoph, Hautle, Patrick, Schwartz, Ilai, Giraudeau, Patrick, Eichhorn, Tim R., and Dumez, Jean‐Nicolas

Subjects
NMR spectrometers, CRYSTALS
Abstract

The HYPNOESYS method (Hyperpolarized NOE System), which relies on the dissolution of optically polarized crystals, has recently emerged as a promising approach to enhance the sensitivity of NMR spectroscopy in the solution state. However, HYPNOESYS is a single‐shot method that is not generally compatible with multidimensional NMR. Here we show that 2D NMR spectra can be obtained from HYPNOESYS‐polarized samples, using single‐scan acquisition methods. The approach is illustrated with a mixture of terpene molecules and a benchtop NMR spectrometer, paving the way to a sensitive, information‐rich and affordable analytical method. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

67. Parahydrogen‐Polarized [1‐13C]Pyruvate for Reliable and Fast Preclinical Metabolic Magnetic Resonance Imaging.

Author

Nagel, Luca, Gierse, Martin, Gottwald, Wolfgang, Ahmadova, Zumrud, Grashei, Martin, Wolff, Pascal, Josten, Felix, Karaali, Senay, Müller, Christoph A., Lucas, Sebastian, Scheuer, Jochen, Müller, Christoph, Blanchard, John, Topping, Geoffrey J., Wendlinger, Andre, Setzer, Nadine, Sühnel, Sandra, Handwerker, Jonas, Vassiliou, Christophoros, and van Heijster, Frits H.A.

Subjects
MAGNETIC resonance imaging, PYRUVATES, POLARIZATION (Nuclear physics), NUCLEAR spin, SPIN polarization, POLARIZERS (Light)
Abstract

Hyperpolarization techniques increase nuclear spin polarization by more than four orders of magnitude, enabling metabolic MRI. Even though hyperpolarization has shown clear value in clinical studies, the complexity, cost and slowness of current equipment limits its widespread use. Here, a polarization procedure of [1‐13C]pyruvate based on parahydrogen‐induced polarization by side‐arm hydrogenation (PHIP‐SAH) in an automated polarizer is demonstrated. It is benchmarked in a study with 48 animals against a commercial dissolution dynamic nuclear polarization (d‐DNP) device. Purified, concentrated (≈70–160 mM) and highly hyperpolarized (≈18%) solutions of pyruvate are obtained at physiological pH for volumes up to 2 mL within 85 s in an automated process. The safety profile, image quality, as well as the quantitative perfusion and lactate‐to‐pyruvate ratios, are equivalent for PHIP and d‐DNP, rendering PHIP a viable alternative to established hyperpolarization techniques. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

69. Parahydrogen-Polarized Fumarate for Preclinical in Vivo Metabolic Magnetic Resonance Imaging

Author

Gierse, Martin, primary, Nagel, Luca, additional, Keim, Michael, additional, Lucas, Sebastian, additional, Speidel, Tobias, additional, Lobmeyer, Tobias, additional, Winter, Gordon, additional, Josten, Felix, additional, Karaali, Senay, additional, Fellermann, Maximilian, additional, Scheuer, Jochen, additional, Müller, Christoph, additional, van Heijster, Frits, additional, Skinner, Jason, additional, Löffler, Jessica, additional, Parker, Anna, additional, Handwerker, Jonas, additional, Marshall, Alastair, additional, Salhov, Alon, additional, El-Kassem, Bilal, additional, Vassiliou, Christophoros, additional, Blanchard, John W., additional, Picazo-Frutos, Román, additional, Eills, James, additional, Barth, Holger, additional, Jelezko, Fedor, additional, Rasche, Volker, additional, Schilling, Franz, additional, Schwartz, Ilai, additional, and Knecht, Stephan, additional

Published
2023
Full Text
View/download PDF

70. Radio-Frequency Sweeps at Microtesla Fields for Parahydrogen-Induced Polarization of Biomolecules

Author

Marshall, Alastair, primary, Salhov, Alon, additional, Gierse, Martin, additional, Müller, Christoph, additional, Keim, Michael, additional, Lucas, Sebastian, additional, Parker, Anna, additional, Scheuer, Jochen, additional, Vassiliou, Christophoros, additional, Neumann, Philipp, additional, Jelezko, Fedor, additional, Retzker, Alex, additional, Blanchard, John W., additional, Schwartz, Ilai, additional, and Knecht, Stephan, additional

Published
2023
Full Text
View/download PDF

71. Correlation of high-field and zero- to ultralow-field NMR properties using 2D spectroscopy.

Author

Zhukov, Ivan V., Kiryutin, Alexey S., Yurkovskaya, Alexandra V., Blanchard, John W., Budker, Dmitry, and Ivanov, Konstantin L.

Subjects
NUCLEAR magnetic resonance, NMR spectrometers, CHEMICAL shift (Nuclear magnetic resonance), SPECTROMETRY, SIGNAL detection, ISOMERISM, NUCLEAR magnetic resonance spectroscopy
Abstract

The field of zero- to ultralow-field (ZULF) nuclear magnetic resonance (NMR) is currently experiencing rapid growth, owing to progress in optical magnetometry and attractive features of ZULF-NMR such as low hardware cost and excellent spectral resolution achieved under ZULF conditions. In this work, an approach is proposed and demonstrated for simultaneous acquisition of ZULF-NMR spectra of individual 13C-containing isotopomers of chemical compounds in a complex mixture. The method makes use of fast field cycling such that the spin evolution takes place under ZULF conditions, whereas signal detection is performed in a high-field NMR spectrometer. This method has excellent sensitivity, also allowing easy assignment of ZULF-NMR spectra to specific analytes in the mixture. We demonstrate that the spectral information is the same as that given by ZULF-NMR, which makes the method suitable for creating a library of ZULF-NMR spectra of various compounds and their isotopomers. The results of the field-cycling experiments can be presented in a convenient way as 2D-NMR spectra with the direct dimension giving the high-field 13C-NMR spectrum (carrying the chemical-shift information) and the indirect dimension giving the ZULF-NMR spectrum (containing information about proton–carbon J-couplings). Hence, the method can be seen as a variant of heteronuclear J-resolved spectroscopy, one of the first 2D-NMR techniques. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

74. The meaning of curriculum development and the role of an outsider

Author

Blanchard, John Arthur

Subjects
370, Education & training
Abstract

The origin of this thesis is a curriculum development project - an enterprise which brought school teachers and advisory teachers together in attempts to improve means by which pupils' achievements are recorded. The thesis explores what one can be conscious of and articulate about in running and developing the curriculum: as a teacher, as an advisory teacher, as an administrator and manager. Throughout, aspects of learning, teaching and curriculum development are treated both at a theoretical level of general discussion and at a practical level of narrative or documentary exemplification. Facets of becoming conscious and articulate are further discussed through intermittent reflections on the thesis-writing process itself. Heuristic and hermeneutic actions are defined through the critical observation of gaps and tensions between intention and effect, participation and explanation, conception and apperception - in teaching, advising, and writing. Alternative attitudes to and motivations in teaching and the treatment of teachers are explored. Attention is paid to different perceptions of what might be regular and what not, what might be repeatable and reversible and what not, what might be a modification of and what a departure from precedents and conventions, and what might be explicit and what implicit, both in teaching and in attempts to change teaching. A crucial focus is predictability and time-dependence. Differences between teacher-practitioners' and non-practitioners' perspectives are discussed. Implications are pursued as far as administration and management are concerned. Practitioners are shown necessarily to operate, however tacitly, at a principled level in order to cope with the multifariousness of the particular situations they confront: what relation such general principles bear to the general principles promoted by non-practitioners needs to be made apparent through the latter's efforts in grasping the particulars of practitioners' experience. Appendices present both working papers intended to guide advisory teachers and material from publications which have informed the thesis and practices dealt with here.

Published
1990

79. Learning Awareness: Constructing Formative Assessment in the Classroom, in the School and across Schools

Author

Blanchard, John

Abstract

This article gives details of the Portsmouth Learning Community Assessment for Learning (AfL) project from 2002 to 2007. A context of research is given and a reframing of formative assessment suggested. Qualitative, positive effects are indicated resulting from teachers' collaborative action research and learners' involvement in classroom experimentation and curriculum design. Classroom and institutional cultures are characterised as more or less open to decision-making by learners and stakeholders. A heuristic, hermeneutic framework is presented, outlining what teachers and learners, as well as stakeholders, managers and leaders, can make explicit for any phase of activity. Conditions thought essential to sustainable development are noted.

Published
2008
Full Text
View/download PDF

80. Radio-Frequency Sweeps at μT Fields for Parahydrogen-Induced Polarization of Biomolecules

Author

Marshall, Alastair, Salhov, Alon, Gierse, Martin, Müller, Christoph, Keim, Michael, Lucas, Sebastian, Parker, Anna, Scheuer, Jochen, Vassiliou, Christophoros, Neumann, Philipp, Jelezko, Fedor, Retzker, Alex, Blanchard, John W., Schwartz, Ilai, and Knecht, Stephan

Subjects
Chemical Physics (physics.chem-ph), FOS: Physical sciences
Abstract

Magnetic resonance imaging of $^{13}$C-labeled metabolites enhanced by parahydrogen-induced polarization (PHIP) can enable real-time monitoring of processes within the body. We introduce a robust, easily implementable technique for transferring parahydrogen-derived singlet order into 13C magnetization using adiabatic radio-frequency sweeps at $μ$T fields. We experimentally demonstrate the applicability of this technique to several molecules, including some molecules relevant for metabolic imaging, where we show significant improvements in the achievable polarization, in some cases reaching above 60%. Furthermore, we introduce a site-selective deuteration scheme, where deuterium is included in the coupling network of a pyruvate ester to enhance the efficiency of the polarization transfer. These improvements are enabled by the fact that the transfer protocol avoids relaxation induced by strongly coupled quadrupolar nuclei.

Published
2022
Full Text
View/download PDF

83. Hyperpolarized Solution-State NMR Spectroscopy with Optically Polarized Crystals

Author

Eichhorn, Tim R., primary, Parker, Anna J., additional, Josten, Felix, additional, Müller, Christoph, additional, Scheuer, Jochen, additional, Steiner, Jakob M., additional, Gierse, Martin, additional, Handwerker, Jonas, additional, Keim, Michael, additional, Lucas, Sebastian, additional, Qureshi, Mohammad Usman, additional, Marshall, Alastair, additional, Salhov, Alon, additional, Quan, Yifan, additional, Binder, Jan, additional, Jahnke, Kay D., additional, Neumann, Philipp, additional, Knecht, Stephan, additional, Blanchard, John W., additional, Plenio, Martin B., additional, Jelezko, Fedor, additional, Emsley, Lyndon, additional, Vassiliou, Christophoros C., additional, Hautle, Patrick, additional, and Schwartz, Ilai, additional

Published
2022
Full Text
View/download PDF

84. Targets, Assessment for Learning, and Whole-School Improvement.

Author

Blanchard, John

Abstract

Develops the idea that there is a gap in theory and practice regarding the relationship between whole-school targets and individual targets. Argues that all of the work in schools concerning use of targets for school improvement, for performance management, and for individual pupils' progress, rests on effective assessment for learning. (BT)

Published
2003

86. Polarization transfer via field sweeping in parahydrogen-enhanced nuclear magnetic resonance.

Author

Eills, James, Blanchard, John W., Wu, Teng, Bengs, Christian, Hollenbach, Julia, Budker, Dmitry, and Levitt, Malcolm H.

Subjects
*NUCLEAR magnetic resonance, *MALEIC acid, *DICARBOXYLIC acids, *MAGNETIC fields, *MAGNETIZATION, *NUCLEAR magnetic resonance spectroscopy
Abstract

We show that in a spin system of two magnetically inequivalent protons coupled to a heteronucleus such as 13C, an adiabatic magnetic field sweep, passing through zero field, transfers the proton singlet order into magnetization of the coupled heteronucleus. This effect is potentially useful in parahydrogen-enhanced nuclear magnetic resonance and is demonstrated on singlet-hyperpolarized [1-13C]maleic acid, which is prepared via the reaction between [1-13C]acetylene dicarboxylic acid and para-enriched hydrogen gas. The magnetic field sweeps are of microtesla amplitudes and have durations on the order of seconds. We show a polarization enhancement by a factor of 104 in the 13C spectra of [1-13C]maleic acid in a 1.4 T magnetic field. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

90. Parahydrogen-Polarized Fumarate for Preclinical in VivoMetabolic Magnetic Resonance Imaging

Author

Gierse, Martin, Nagel, Luca, Keim, Michael, Lucas, Sebastian, Speidel, Tobias, Lobmeyer, Tobias, Winter, Gordon, Josten, Felix, Karaali, Senay, Fellermann, Maximilian, Scheuer, Jochen, Müller, Christoph, van Heijster, Frits, Skinner, Jason, Löffler, Jessica, Parker, Anna, Handwerker, Jonas, Marshall, Alastair, Salhov, Alon, El-Kassem, Bilal, Vassiliou, Christophoros, Blanchard, John W., Picazo-Frutos, Román, Eills, James, Barth, Holger, Jelezko, Fedor, Rasche, Volker, Schilling, Franz, Schwartz, Ilai, and Knecht, Stephan

Abstract

We present a versatile method for the preparation of hyperpolarized [1-13C]fumarate as a contrast agent for preclinical in vivoMRI, using parahydrogen-induced polarization (PHIP). To benchmark this process, we compared a prototype PHIP polarizer to a state-of-the-art dissolution dynamic nuclear polarization (d-DNP) system. We found comparable polarization, volume, and concentration levels of the prepared solutions, while the preparation effort is significantly lower for the PHIP process, which can provide a preclinical dose every 10 min, opposed to around 90 min for d-DNP systems. With our approach, a 100 mM [1-13C]-fumarate solution of volumes up to 3 mL with 13–20% 13C-hyperpolarization after purification can be produced. The purified solution has a physiological pH, while the catalyst, the reaction side products, and the precursor material concentrations are reduced to nontoxic levels, as confirmed in a panel of cytotoxicity studies. The in vivousage of the hyperpolarized fumarate as a perfusion agent in healthy mice and the metabolic conversion of fumarate to malate in tumor-bearing mice developing regions with necrotic cell death is demonstrated. Furthermore, we present a one-step synthesis to produce the 13C-labeled precursor for the hydrogenation reaction with high yield, starting from 13CO2as a cost-effective source for 13C-labeled compounds.

Published
2023
Full Text
View/download PDF

93. Teachers' Motivations and Satisfactions in Developing Their Own Curricula.

Author

Schamroth, Norman and Blanchard, John

Abstract

Uses examples of curriculum development efforts undertaken within a government-funded pilot project to illustrate how teachers can take advantage of curriculum development resources and opportunities. Addresses teacher motives and satisfactions in curriculum development and ways in which administrators might take account of those feelings to improve the development process. (SG)

Published
1990

96. Photochemically Induced Dynamic Nuclear Polarization of Heteronuclear Singlet Order

Author

Sheberstov, Kirill F., primary, Chuchkova, Liubov, additional, Hu, Yinan, additional, Zhukov, Ivan V., additional, Kiryutin, Alexey S., additional, Eshtukov, Artur V., additional, Cheshkov, Dmitry A., additional, Barskiy, Danila A., additional, Blanchard, John W., additional, Budker, Dmitry, additional, Ivanov, Konstantin L., additional, and Yurkovskaya, Alexandra V., additional

Published
2021
Full Text
View/download PDF

98. Search for Axionlike Dark Matter Using Solid-State Nuclear Magnetic Resonance

Author

Aybas, Deniz, primary, Adam, Janos, additional, Blumenthal, Emmy, additional, Gramolin, Alexander V., additional, Johnson, Dorian, additional, Kleyheeg, Annalies, additional, Afach, Samer, additional, Blanchard, John W., additional, Centers, Gary P., additional, Garcon, Antoine, additional, Engler, Martin, additional, Figueroa, Nataniel L., additional, Sendra, Marina Gil, additional, Wickenbrock, Arne, additional, Lawson, Matthew, additional, Wang, Tao, additional, Wu, Teng, additional, Luo, Haosu, additional, Mani, Hamdi, additional, Mauskopf, Philip, additional, Graham, Peter W., additional, Rajendran, Surjeet, additional, Kimball, Derek F. Jackson, additional, Budker, Dmitry, additional, and Sushkov, Alexander O., additional

Published
2021
Full Text
View/download PDF

99. Zero and Ultra-Low-Field Nuclear Magnetic Resonance Spectroscopy Via Optical Magnetometry

Author

Blanchard, John Woodland

Subjects
Chemistry, Atomic physics, J-Coupling, J-Spectroscopy, Nuclear Magnetic Resonance, Optical Magnetometry, Spin Dynamics, Zero-Field NMR
Abstract

Nuclear magnetic resonance (NMR) is among the most powerful analytical tools available to the chemical and biological sciences for chemical detection, characterization, and structure elucidation. NMR experiments are usually performed in large magnetic fields in order to maximize sensitivity and increase chemical shift resolution. However, the high magnetic fields required for conventional NMR necessitate large, immobile, and expensive superconducting magnets, limiting the use of the technique. New hyperpolarization and non-inductive detection methods have recently allowed for NMR measurements in the inverse regime of extremely low magnetic fields. Whereas a substantial body of research has been conducted in the high-field regime, taking advantage of the efficient coherent control afforded by a spectroscopy dominated by coupling to the spectrometer, the zero- and ultra-low-field (ZULF) regime has remained mostly unexplored. In this dissertation, we investigate the applicability of ZULF-NMR as a novel spectroscopic technique complimentary to high-field NMR.In particular, we consider various aspects of the ZULF-NMR experiment and the dynamics of nuclear spins under various local spin coupling Hamiltonians. We first survey zero-field NMR experiments on systems dominated by the electron-mediated indirect spin-spin coupling (J-coupling). The resulting J-spectra permit precision measurement of chemically relevant information due to the exquisite sensitivity of J-couplings to subtle changes in molecular geometry and electronic structure. We also consider the effects of weak magnetic fields and residual dipolar couplings in anisotropic media, which encode information about nuclear magnetic moments and geometry, and further resolve topological ambiguities by lifting degeneracies. By extending the understanding of the interactions that contribute to ZULF-NMR spectra, this work represents a significant advancement towards a complete description of zero- and ultra-low-field nuclear magnetic resonance spectroscopy.

Published
2014

Catalog

Books, media, physical & digital resources
See catalog results