A riser support system for use in a body of water comprises a buoyant and ballastable support structure and a plurality of substantially vertical and rigid risers each of which is attached to the inside of the support structure at a location below the center of buoyancy of the support structure and below the surface of the body of water. 5% by weight of a ester-linked quaternary ammonium fabric softening material comprising at least one mono-ester linked component and at least one tri-ester linked component, and a fatty complexing agent wherein the weight ratio of the mono-ester linked component of compound to fatty complexing agent is from 5:1 to 1:5. The number of RF channels upon which measurements are performed may be determined adaptivelydynamically. the portion of the length of suture is retrieved through the wall of the graft to the opposite side of the wall. The optical bus can also be connected with a second transceiver that may be used to deliver optical power to the attached nodes. The Shore A hardness of the present polymer gel compositions at room temperature is preferably less than about 30.