  We have extracted QCD matrix elements from our data on double polarized
inelastic scattering of electrons on nuclei. We find the higher twist matrix
element \tilde{d_2}, which arises strictly from quark- gluon interactions, to
be unambiguously non zero. The data also reveal an isospin dependence of higher
twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The
fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied
at our low momentum transfer.
