I don't think I posted this one already.
Tayler, M.C.D., et al., Direct Enhancement of Nuclear Singlet Order by Dynamic Nuclear Polarization. J. Am. Chem. Soc., 2012. 134(18): p. 7668-7671.
Hyperpolarized singlet order is available immediately after dissolution DNP, avoiding need for additional preparation steps. We demonstrate this procedure on a sample of [1,2?13C2]pyruvic acid.