  We review the Four-Dimensional-Formulation variant of the
Four-Dimensional-Helicity scheme, by showing two applications of this
regularisation scheme. The first one is the computation of one-loop helicity
amplitudes, for which we present preliminary results for the analytic
expressions of the one-loop Higgs plus five- gluon amplitudes. In the second
part, we study the Colour-Kinematics duality for off-shell diagrams in gauge
theories coupled to matter, showing in a diagrammatic way that the Jacobi
relations for the kinematic numerators of off-shell diagrams, built with
Feynman rules in axial gauge, reduce to definite set of violating terms due to
the contributions of sub-graphs only.
