  The high parton density regime of the Quantum Chromodynamics (QCD), where the
physics of parton saturation is expected to be dominant, is briefly discussed.
Some phenomenological aspects of saturation are described, mainly focusing on
possible signatures of the non-linear QCD dynamics in the heavy quark
production in electron-proton/nucleus collisions. Implications of these effects
in the heavy quark production in ultraperipheral heavy-ion collisions are also
presented.
