ABSTRACT
Objective To investigate the biomechanical behavior of porous scaffold with different materials (Ti, Ta, PEEK, HA) for repairing rabbit femur defects under immediate loading by three-dimensional finite element analysis (FEA), so as to explore the best porous scaffold material from the perspective of biomechanics. Methods The CBCT combined with software such as Mimics, SolidWorks, Geomagic Studio, ANSYS were used to establish an immediate loading model for the repair of rabbit femur defects with porous scaffolds at different stages of bone healing. The stress and strain distributions on the scaffolds and the surrounding tissues were calculated. Results The maximum equivalent stress of porous scaffold decreased along with the bone healing. In the granulation tissue and fibrous tissue model, the ratio of the maximum equivalent stress to the yield strength of porous scaffold was: HA＞Ta＞PEEK＞Ti. The maximum equivalent stress of the HA porous scaffold was greater than its yield strength. The number of suitable strain elements in tissues around the porous scaffolds was: PEEK＞Ta＞Ti＞HA. The number of potential fracture strain elements in tissues around the porous scaffolds was: HA＞Ta＞PEEK＞Ti. Conclusions The HA porous scaffold could not bear the immediate load and guide bone healing well under immediate loading. The elastic modulus of PEEK porous scaffold was similar to that of bone tissues, which could preferably guide bone healing. PEEK was an ideal porous scaffold material under immediate loading. The research findings provide
ABSTRACT
Effects of yucca extract (YE) on feed efficiency, immune and antioxidative function in Arbor Acres broilers were studied. One hundred and twenty-eight fourteen-day-old broiler chickens were randomly divided into four treatments with four replicates of 8 birds each. These four diets were formulated by adding 0, 100, 200 and 300 mg/kg YE to the basal diet. The results showed that: diets supplemented with 100 and 200 mg/kg YE increased average body weight gain, feed efficiency, IgG, IgM, T-AOC, CAT and SOD levels, and have positive effects on inducing immune organs' maturation. In addition, 100 mg treatment mainly improved the feed efficiency whereas 200 mg treatment mainly acted on immunity and anti-oxidation. In conclusion, YE can be used as a feed additive due to its capability to improve feed efficiency, immune and antioxidative function in broilers.