A high-speed digital level shifter is described. That supply rail is formed of first segments located on a first metallization level and second segments located on a second metallization level with at least one conductor element extending between the first and second segments to electrically connect successive segments of the supply rail. Unlike classical steroid receptors, SXR heterodimerizes with RXR and binds to directly repeated sequences related to the half-site, AGTTCA. In still another embodiment, two end caps are provided that may nest with each other.