An xy stage assembly having an xy stage supported by support shafts and having preload shafts applying a load to the xy stage. The compounds are of formula : in which z is a single bond or an optionally substituted linking group, R1 is a halo-alkyl group; and A is an optionally substituted aromatic heterocyclic or carbocyclic ring system; or a salt thereof. The multi-port memory cell includes a first pair of access transistors of a first type, each coupled to the input node of a respective one of the first and second inverter circuits. The methods for powering up the optical network of the embodiments of the invention apply to both new optical networks and to new optical links added to pre-existing optical networks. Simultaneously with the arrangement of the FFC on a vehicle-body-panel-side portion of the roof trim, the room lamp is mounted in the lamp mounting window. The electron acceptor is attached to or adjacent to the quantum rod.