  We present results of the linear and non-linear rheology of cubic blue phase
I (BPI). The elasticity of BPI is dominated by double-twist cylinders assembled
in a body-centered cubic lattice, which can be specified by disclination lines.
We find that the elasticity of BPI is enhanced by an order of magnitude by
applying pre-shear. The shear-enhanced elasticity is attributed to a
rearrangement of the disclination lines that are arrested in a metastable
state. Our results are relevant for the understanding of the dynamics of
disclinations in cubic blue phases.
