title: Recycling and imaging of nuclear singlet hyperpolarization.
abstract: The strong enhancement of NMR signals achieved by hyperpolarization decays, at best, with a time constant of a few minutes. Here, we show that a combination of long-lived singlet states, molecular design, magnetic field cycling, and specific radiofrequency pulse sequences allows repeated observation of the same batch of polarized nuclei over a period of 30 min and more. We report a recycling protocol in which the enhanced nuclear polarization achieved by dissolution-DNP is observed with full intensity and then returned to singlet order. MRI experiments may be run on a portion of the available spin polarization, while the remaining is preserved and made available for a later use. An analogy is drawn with a "spin bank" or "resealable container" in which highly polarized spin order may be deposited and retrieved.
authors.affiliation: Department of Chemistry, University of Southampton , Southampton SO17 1BJ, United Kingdom.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pileio
authors.forename: Sean
authors.initials: S
authors.lastname: Bowen
authors.forename: Christoffer
authors.initials: C
authors.lastname: Laustsen
authors.forename: Michael C D
authors.initials: MC
authors.lastname: Tayler
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Hill-Cousins
authors.forename: Lynda J
authors.initials: LJ
authors.lastname: Brown
authors.forename: Richard C D
authors.initials: RC
authors.lastname: Brown
authors.forename: Jan H
authors.initials: JH
authors.lastname: Ardenkjaer-Larsen
authors.forename: Malcolm H
authors.initials: MH
authors.lastname: Levitt
mesh_terms: D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy
chemical_list: D002247:Carbon Isotopes