  We discuss some recent results for the properties of doped antiferromagnets,
obtained within the planar t-J model mainly by the finite-temperature Lanczos
method, with the emphasis on the comparison with experimental results in
cuprates. Among the thermodynamic properties the chemical potential and entropy
are considered, as well as their relation to the thermoelectric power. At the
intermediate doping model results for the optical conductivity, the dynamical
spin structure factor and spectral functions reveal a marginal Fermi-liquid
behaviour, close to experimental findings. It is shown that the universal form
of the optical conductivity follows quite generally from the overdamped
character of single-particle excitations.
