Advances in Dynamization of Plate Fixation to Promote Natural Bone Healing.

The controlled dynamization of fractures can promote natural fracture healing by callus formation, while overly rigid fixation can suppress healing. The advent of locked plating technology enabled new strategies for the controlled dynamization of fractures, such as far cortical locking (FCL) screws or active plates with elastically suspended screw holes. However, these strategies did not allow for the use of non-locking screws, which are typically used to reduce bone fragments to the plate.

The role of feedback in the formation of morphogen territories.

In this paper, we consider a mathematical model for the formation of spatial morphogen territories of two key morphogens: Wingless (Wg) and Decapentaplegic (DPP), involved in leg development of Drosophila. We define a gene regulatory network (GRN) that utilizes autoactivation and cros-sinhibition (modeled by Hill equations) to establish and maintain stable boundaries of gene expression. By computational analysis we find that in the presence of a general activator, neither autoactivation, nor cross-inhibition alone are sufficient to maintain stable sharp boundaries of morphogen production in the leg disc.