A strobe offset control circuit is disclosed. In certain embodiments disclosed herein M is a group \u2014P-A-P\u2014 where A isCertain substituted aliphanes, cyclophanes, heteraphanes, heterophanes, hetero-heteraphanes and metallocenes disclosed herein are potent andor selective inhibitors of viral replication, particularly Hepatitis C virus replication. A firing recess just to the rear of a bore defined in a firearm barrel receives the topmost chamber tube and cartridge and is urged against a partially circular contour defined within the recess by a feed spring which contour center is aligned with the bore. Regeneration of the supervisory signal is provided in at least one device disposed along the optical link in order to counteract attenuation introduced on the supervisory signal by the co-propagating Raman amplifiers.