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Abstract: Compact layers are used in dye-sensitized solar cells (DSSCs) to passivate transparent conducting oxides (TCOs). TCO passivation increases DSSC performance by reducing electrical loss from recombination at the TCO-electrolyte interface and by improving electrical contact between the TCO and TiO2 photoelectrode. A novel process for synthesis of 4.5nm colloidal TiO2 compact layer particles via acid hydrolysis of titanium isopropoxide was developed. DSSCs fabricated with the colloidal TiO2 compact layer, with no compact layer, and those with an RF-sputtered compact layer were evaluated. Relative to a DSSC with no compact layer, the colloidal compact layer improved the short-circuit current density, fill factor, and solar energy conversion efficiency by 17.6%, 4.4%, and 25.3%, respectively. Relative to the sputtered compact layer, the colloidal compact layer improved the short-circuit current density and solar energy conversion efficiency by 5.5% and 5.3%, respectively, with no significant change in the fill factor. The improved DSSC characteristics were attributed to increased shunt resistance due to decreased electrolyte reduction at the TCO-electrolyte interface and decreased series resistance due to improved electrical contact between the TCO and the TiO2 photoelectrode. [Copyright &y& Elsevier]

Objective: Microfracture is used to treat articular cartilage injuries, but leads to the formation of fibrocartilage rather than native hyaline articular cartilage. Since bone morphogenetic protein 7 (BMP-7) induces cartilage differentiation, we hypothesized that the addition of the morphogen would improve the repair tissue generated by microfracture. We determined the effects of these two treatments alone and in combination on the quality and quantity of repair tissue formed in a model of full-thickness articular cartilage injury in adolescent rabbits.Design: Full-thickness defects were made in the articular cartilage of the patellar grooves of forty, 15-week-old rabbits. Eight animals were then assigned to (1) no further treatment (control), (2) microfracture, (3) BMP-7, (4) microfracture with BMP-7 in a collagen sponge (combination treatment), and (5) microfracture with a collagen sponge. Animals were sacrificed after 24 weeks at 39 weeks of age. The extent of healing was quantitated by determining the thickness and the surface area of the repair tissue. The quality of the repair tissue was determined by grading specimens using the International Cartilage Repair Society Visual Histological Assessment Scale.Results: Compared to controls, BMP-7 alone increased the amount of repair tissue without affecting the quality of repair tissue. Microfracture improved both the quantity and surface smoothness of repair tissue. Compared to either single treatment, the combination of microfracture and BMP-7 increased both the quality and quantity of repair tissue.Conclusions: Microfracture and BMP-7 act synergistically to stimulate cartilage repair, leading to larger amounts of repair tissue that more closely resembles native hyaline articular cartilage. [ABSTRACT FROM AUTHOR]

Abstract: Objective: In developing countries, tibial shaft fractures are frequently stabilised using Surgical Implant Generation Network (SIGN) nails. Despite widespread use throughout the world, little is known regarding their biomechanical properties. This study aimed to compare the mechanical stiffness of the SIGN tibial nail with a standard hollow tibial nail. Methods: A fracture gap model was created to simulate a comminuted mid-shaft tibia fracture (AO/OTA42-C3) using synthetic composite bones. The constructs were stabilised with either a 9mm solid SIGN nail or a 10mm hollow Russell–Taylor nail. Both nail systems were interlocked proximally and distally. Following fixation, the specimens were loaded in axial, torsional, and cyclical axial modes to calculate construct stiffness and irreversible (plastic) deformation. Results: The mean axial stiffness for the SIGN nail constructs was 47% higher than mean stiffness for the RT nail constructs (p <0.001). The difference in torsional stiffness was not statistically significant. However, the SIGN group demonstrated 159% more irreversible deformation than the Russell–Taylor group (p =0.006) for the loading parameters studied. Conclusion: The SIGN tibial nail, despite its slightly smaller diameter, can provide similar construct stiffness and stability, when compared to a larger hollow nail for stabilisation of tibial shaft fractures. [Copyright &y& Elsevier]