No abstract

This study investigated the use of a prototype expanded polytetrafluoroethylene membrane attached to bone with butyl-cyanoacrylate, in facilitating guided bone regeneration into bone defects and around titanium screws in rabbit femora. Two experimental models were used to assess bone growth. The first model investigated two unicortical defects in each femora. The second was bone growth in a 500-micron engineered space around one transcortical titanium screw. In the first model there was a significant increase in bone formation at 1 and 2 months in the membrane groups (p < 0.01) as compared to the controls. In the second model the percentage of bone in contact with the implant was significant at 1 and 2 months in the defects covered with membrane compared to the uncovered defects. The uncovered defects had fibrous tissue adherent to the implant continuous with the overlying soft tissue. Our study demonstrated three points: this membrane can be used to increase bone regeneration into defects, this technique allows bone to grow directly around an implant, and butyl-cyanoacrylate can be used in deep soft tissue and bone applications without any apparent deleterious effects.

This paper presents a design study of the geometry of the ports on a layered core heat exchanger, which is used in automotive engines. Using fluid dynamics, and fluid computational programs, the performance characteristics of a double boss port design was obtained as well as a single boss port design. The two designs were compared, and an optimized design shall be proposed. This optimization study compares the fluid flow and overall heat transfer of the layered core heat exchanger.