Highly water-soluble ubiquinone-0 (CoQ0) reacts with ascorbate monoanion (Asc) to mediate the production of ascorbyl free radicals (AFR). Using aqueous reaction mixture of CoQ0 and Asc, we obtained positively enhanced dynamic nuclear polarization (DNP)-magnetic resonance (MR) images of the AFR at low frequency (ranging from 515 to 530 MHz) of electron spin resonance (ESR) irradiation. The shape of the determined DNP spectrum was similar to ESR absorption spectra with doublet spectral peaks. The relative locational relationship of spectral peaks in the DNP spectra between the AFR (520 and 525 MHz), 14N-labeled carbamoyl-PROXYL (14N-CmP) (526.5 MHz), and Oxo63 (522 MHz) was different from that in the X-band ESR spectra, but were similar to that in the 300-MHz ESR spectra. The ratio of DNP enhancement to radical concentration for the AFR was higher than those for 14N-CmP, Oxo63, and flavin semiquinone radicals. The spectroscopic DNP properties observed for the AFR were essentially the same as those for AFR mediated by pyrroloquinoline quinone. Moreover, we made a success of in vivo DNP-MR imaging of the CoQ0-mediated AFR which was administered by the subcutaneous and oral injections as an imaging probe.
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A tailored multi-frequency EPR approach to accurately determine the magnetic resonance parameters of dynamic nuclear polarization agents: application to AMUPol #DNPNMR
From The DNP-NMR Blog:
A tailored multi-frequency EPR approach to accurately determine the magnetic resonance parameters of dynamic nuclear polarization agents: application to AMUPol #DNPNMR
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This is a very nice article illustrating the importance of understanding the EPR parameters of a polarizing agent used in DNP-NMR spectroscopy. Here the 9, 95 and 275 GHz EPR spectroscopy is used to characterize AMUPol and predict its performance in high-field DNP.
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06-05-2017 03:59 PM
Dissolution dynamic nuclear polarization–enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions #DNPNMR
From The DNP-NMR Blog:
Dissolution dynamic nuclear polarization–enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions #DNPNMR
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Lee, Y., Dissolution dynamic nuclear polarization–enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions. Applied Spectroscopy Reviews, 2015. 51(3): p. 210-226.
https://doi.org/10.1080/05704928.2015.1116078
nmrlearner
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12-30-2016 04:53 PM
Dynamic nuclear polarization in solid samples by electrical-discharge-induced radicals
From The DNP-NMR Blog:
Dynamic nuclear polarization in solid samples by electrical-discharge-induced radicals
Katz, I. and A. Blank, Dynamic nuclear polarization in solid samples by electrical-discharge-induced radicals. J Magn Reson, 2015. 261: p. 95-100.
http://www.ncbi.nlm.nih.gov/pubmed/26547016
Dynamic nuclear polarization enhancement of protons and vanadium-51 in the presence of pH-dependent vanadyl radicals
From The DNP-NMR Blog:
Dynamic nuclear polarization enhancement of protons and vanadium-51 in the presence of pH-dependent vanadyl radicals
Perez Linde, A.J., et al., Dynamic nuclear polarization enhancement of protons and vanadium-51 in the presence of pH-dependent vanadyl radicals. Magn Reson Chem, 2015. 53(2): p. 88-92.
http://www.ncbi.nlm.nih.gov/pubmed/25228149
Dynamic nuclear polarization-magnetic resonance imaging at low ESR irradiation frequency for ascorbyl free radicals
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