A magnetic tape cartridge loader and unloader includes a platform positionable in front of a storage slot of a storage magazine and having a pivotable gripper that releases the cartridge from the storage slot, engages and pulls the cartridge from the slot onto the platform with a hook, engages a back edge of the cartridge with a second hook, and pushes the cartridge into a tape streaming device. An optical system including a plane parallel plate may be employed to change the system focal distance. The ring may be made of ferroelectric or magnetic material. Strategic placement of slots in the nozzle case that direct more flow at the portion of the injector body that houses the actuator and solenoid assembly may also be employed. Various types of agents that inhibit or otherwise hinder the production, release or activity of eotaxin may be used therapeutically in the treatment of asthma and other inflammatory diseases. A cutting corner is formed between a primary cutting edge and a secondary cutting edge.