Biomedical subjects

AS Heindrichs

Publications and source records attributed to AS Heindrichs.

2 recordsLinked to original sources

PubMed2000

MAS double-quantum filtered dipolar shift correlation spectroscopy

A carbon-13 magic angle spinning double-quantum filtered dipolar shift correlation NMR experiment which can be used to establish through-space connectivities in solids is analyzed. The main advantage of the double-quantum filtered approach is the removal of intensity arising from natural abundance background signals. The variation in intensity of the cross and diagonal peaks observed in the two-dimensional spectrum as a function of mixing time is investigated experimentally for model systems. The observed behavior is compared with analytical expressions derived for three coupled spins, as well as with simulations based on average Hamiltonian theory. Copyright 2000 Academic Press.

Journal Article↗

PubMed1999

Spin counting with fast MAS

A novel magic angle spinning (MAS) multiple-quantum spin counting experiment based on the C7 recoupling sequence of Lee et al. is described. In contrast to previous approaches the new experiment is applicable at fast MAS rates and can be used to follow the multiple-quantum excitation dynamics with fine time resolution. The new method is illustrated by experiments on adamantane at spinning speeds comparable to the nonspinning dipolar linewidth. The sizes of the clusters of dipolar-coupled spins measured using the new experiment are compared to those obtained using the original nonspinning spin counting technique of Baum et al. Copyright 1999 Academic Press.

Journal Article↗