Abstract: There are disclosed processes for preparing biodegradable collagen-based matrices in sponge or sheet form wherein in one embodiment a collagen-based material including a collagen selected from the group consisting of types I, II and II collagens is freeze dried to form a collagen-based sponge which is contacted with a cross-linking agent selected from the group consisting of a carbodiimide or a succinimidyl active ester to form an intermediate collagen-based matrix which is subsequently subjected to conditions of severe dehydration to form the collagen-based matrix in sponge or sheet form. In another embodiment, a collagen-based sponge or sheet is first subjected to conditions of severe dehydration followed by contacting the thus formed intermediate collagen-based matrix with a carbodiimide crosslinking compound to form the collagen-based matrix in sponge or sheet form.

Abstract: A light powered rotating detection mirror includes a detection mirror formed of two back-to-back convex mirrors; a motor having a rotatable shaft from which the detection mirror is supported by a first interconnecting chain; a housing and a second interconnecting chain for supporting the motor from a ceiling; a sleeve positioned in surrounding relation to a fluorescent bulb; a solar cell positioned between the sleeve and the fluorescent bulb for converting light energy to electrical energy; and electrical wires connecting the solar cell to the motor for actuating the motor to rotate the detection mirror.