An anti-tip system is provided for improving the stability of a powered vehicle, such as a powered wheelchair. The stent of the present invention has an elongated side aperture which is designed to be implanted next to the area of septal perforators to prevent covering of the orifices of the septal perforators. The image data may be expanded to exploit the dynamic range of the target display without affecting mid-tone values. Identified clones containing a biomolecule or bioactivity of interest can be further variegated or the DNA contained in the clone can be variegated to create novel biomolecules or bioactivities of interest.