  Experimental data on the F2 structure functions of the proton and deuteron,
including recent results from CLAS at Jefferson Lab, have been used to
construct their n<=12 moments. A comprehensive analysis of the moments in terms
of the operator product expansion has been performed to separate the moments
into leading and higher twist contributions. Particular attention was paid to
the issue of nuclear corrections in the deuteron, when extracting the neutron
moments from data. The difference between the proton and neutron moments was
compared directly with lattice QCD simulations. Combining leading twist moments
of the neutron and proton we found the d/u ratio at x->1 approaching 0,
although the precision of the data did not allow to exclude the 1/5 value. The
higher twist components of the proton and neutron moments suggest that
multi-parton correlations are isospin independent.
