Relative abundances of Ti and Ni with respect to Zn against [Zn/Fe] (top). Dust depletion of Ti and Ni against [Zn/Fe] and the linear fits for the QSO-DLAs (black triangles and black dashdotted line) for the Milky Way (green points and dashed green line), for the LMC (purple stars and dash-dot-dotted purple densely line), for the SMC (blue triangles and dash-dotted blue line), and for the GRB-DLAs (orange diamonds and dotted orange line; bottom). The 3σ upper limits are shown with gray arrows. The solid red line shows the linear fit to the merged data.