From molecular quantum electrodynamics at finite temperatures to nuclear magnetic resonance

The algebraic reformulation of molecular Quantum Electrodynamics ( mQED ) at fi nite temperatures is applied to Nuclear Magnetic Resonance ( NMR ) in order to provide a foundation for the reconstruction of much more detailed molecular structures, than possible with current methods. Conventional NMR theories are directly related to the effective spin model, which idealizes nuclei as fi xed points in a lattice 3 . However, the delocalization of spins due to the thermal energy is more realistically described by the amplitude square of the nuclear wave function |Ψ β ( X )| 2 with Î X n3 , instead of fi xed points in 3 . In addition, the phenomenological integration of thermalization only allows an investigation of the molecular structure based on the position of the punctiform center of an NMR signal, but not based on the width and shape of NMR signals. Hence, a lot information on molecular structures remain hidden in experimental NMR data. In this document it is shown how |Ψ β ( X )| 2 , Î X n3 can be reconstructed from NMR data. To this end, it is shown how NMR spectra can be calculated directly from mQED at fi nite temperatures without involving the effective description. The new method connects all data points — the positions, widths, heights and shapes —description. The new method connects all data points — the positions, widths, heights and shapes — of NMR signals directly with the molecular structure, which allows more detailed investigations of the underlying system. Furthermore, it is shown that the presented method corrects wrong predictions of the effective spin model. The fundamental problem of performing numerical calculations with the in fi nite-dimensional radiation fi eld is solved by using a puri fi ed representation of a KMS state on a W * -algebra

Performance and reproducibility of 13C and 15N hyperpolarization using a cryogen-free DNP polarizer

The setup, operational procedures and performance of a cryogen-free device for producing hyperpolarized contrast agents using dissolution dynamic nuclear polarization (dDNP) in a preclinical imaging center is described. The polarization was optimized using the solid-state, DNP-enhanced NMR signal to calibrate the sample position, microwave and NMR frequency and power and flip angle. The polarization of a standard formulation to yield ~ 4 mL, 60 mM 1-13C-pyruvic acid in an aqueous solution was quantified in five experiments to P(13C) = (38 ± 6) % (19 ± 1) s after dissolution. The mono-exponential time constant of the build-up of the solid-state polarization was quantified to (1032 ± 22) s. We achieved a duty cycle of 1.5 h that includes sample loading, monitoring the polarization build-up, dissolution and preparation for the next run. After injection of the contrast agent in vivo, pyruvate, pyruvate hydrate, lactate, and alanine were observed, by measuring metabolite maps. Based on this work sequence, hyperpolarized 15N urea was obtained (P(15N) = (5.6 ± 0.8) % (30 ± 3) s after dissolution)

Homage to Professor INUZUKA Susumu

千葉大学「人文研究」第41

Parahydrogen and Radiofrequency Amplification by Stimulated Emission of Radiation Induce Through-Space Multinuclear NMR Signal Enhancement

Hyperpolarized (i.e., polarized far beyond the thermal equilibrium) nuclear spins can result in radiofrequency amplification by stimulated emission of radiation (RASER) effect. Here, we show the utility of RASER to amplify NMR signals of solute and solvent molecules in the liquid state. Specifically, parahydrogen-induced RASER was used to spontaneously enhance nuclear spin polarization of protons and heteronuclei (here 19F and 31P) in a wide range of molecules. The magnitude of the effect correlates with the T1 relaxation time of the target nuclear spins. A series of control experiments validates the through-space dipolar mechanism of RASER-assisted polarization transfer between parahydrogen-polarized compound and to-be-hyperpolarized nuclei of the target molecule. Frequency-selective saturation of RASER-active resonances was used to control the RASER and the amplitude of spontaneous polarization transfer. Spin dynamics simulations support our experimental RASER studies

MR imaging parameters.

<p>MR imaging parameters.</p