A mathematical model for photoreceptor interactions.

The interactions between rods and cones in the retina have been the focus of innumerable experimental and theoretical biological studies in previous decades yet the understanding of these interactions is still incomplete primarily due to the lack of a unified concept of cone photoreceptor organization and its role in retinal diseases. The low abundance of cones in many of the non-primate mammalian models that have been studied make conclusions about the human retina difficult. A more complete knowledge of the human retina is crucial for counteracting the events that lead to certain degenerative diseases, in particular those associated with photoreceptor cell death (e.

Mechanical and thermal properties of novel polymerized NDGA-gelatin hydrogels.

Nordihydroguaiaretic acid (NDGA), an antioxidant with two functional ortho-catechols from the creosote bush, has been shown to increase the mechanical properties of synthetic collagen fibers, producing biologically based, biocompatible fibers with material properties in uniaxial tensile tests to failure that are comparable to those of native tendon (Koob and Hernandez, Biomaterials 23 (2002) 203; Koob et al., J Biomed Mater Res, 56 (2001) 31; 56 (2001) 40). The NDGA polymerization scheme was applied to gelatin hydrogels to determine whether it could provide a viable approach for producing gelatin based biological materials with advantageous mechanical and thermal properties.

Material properties of polymerized NDGA-collagen composite fibers: development of biologically based tendon constructs.

Methods for stabilizing collagen-based materials with catechol containing monomers were developed in order to produce fibers with mechanical properties in tension comparable to those of normal tendon. Fibers produced from pepsin solubilized, bovine tendon type I collagen were polymerized with the di-catechol nordihydroguaiaretic acid (NDGA). Polymerization was based on the chemical oxidation of the constituent o-catechols to reactive o-quinone functionalities.