This invention relates to a fastener driving device including a variable ratio gear mechanism that enables the ratio of the rotation of the handle to the rotation of a driving bit extending from the handle to be varied to allow the bit to rotate at different speeds from the handle. An urging force for urging moving members toward an interlocking movement member that is moved along the optical axis by a feed screw is cut off by regulating portions. Under ordinary conditions, the structure still has sufficient stiffness for loading goods. In another embodiment, the nuclear core is separated from an outer sheath of the bioincorporable fabric by an intermediate ligament encasement that surrounds the purely polymeric core In either embodiment, each edge of the outer fabric that interfaces a vertebral end plate is impregnated with an agent to stimulate osseus incorporation and anchoring. The invention can involve obtaining a plurality of sequence reads from a sample, identifying one or more sets of duplicative sequence reads within the plurality of sequence reads, and storing only one of the sequence reads from each set of duplicative sequence reads in a text file using nucleotide characters.