We review the transport properties of different
nanostructures produced by ion- and electron-beam
deposition, as prepared as well as after certain treatments.
In general, the available literature indicates that the
transport properties are determined by conduction
processes typical for disordered metallic grains embedded
in a carbon-rich matrix, including intergrain tunneling and
variable range hopping mechanisms. Special emphasis is
given to the superconducting behavior found in certain
Tungsten-Carbide nanostructures that, in a certain field
and temperature range, is compatible with that of granular
superconductivity. This granular superconductivity leads
to phenomena like magnetic field oscillations as well as
anomalous hysteresis loops in the magnetoresistance.