A Particle Model for Prediction of Cement Infiltration of Cancellous Bone in Osteoporotic Bone Augmentation.

PMC3693961Femoroplasty is a potential preventive treatment for osteoporotic hip fractures. It involves augmenting mechanical properties of the femur by injecting Polymethylmethacrylate (PMMA) bone cement. To reduce the risks involved and maximize the outcome, however, the procedure needs to be carefully planned and executed. An important part of the planning system is predicting infiltration of cement into the porous medium of cancellous bone. We used the method of Smoothed Particle Hydrodynamics (SPH) to model the flow of PMMA inside porous media. We modified the standard formulation of SPH to incorporate the extreme viscosities associated with bone cement. Darcy creeping flow of fluids through isotropic porous media was simulated and the results were compared with those reported in the literature. Further validation involved injecting PMMA cement inside porous foam blocks - osteoporotic cancellous bone surrogates - and simulating the injections using our proposed SPH model. Millimeter accuracy was obtained in comparing the simulated and actual cement shapes. Also, strong correlations were found between the simulated and the experimental data of spreading distance (R2 = 0.86) and normalized pressure (R2 = 0.90). Results suggest that the proposed model is suitable for use in an osteoporotic femoral augmentation planning framework.JH Libraries Open Access Fun

The Amount and Timing of Foliar Urea Application Effect on Maize and Forage Sorghum Proteins

This study was carried out for investigating the effect of amount and timing of foliar urea in increasing silage yield and protein content of fodder, in a maize field in Neyshabour, Khorasan Razavi Province during 2011 summer crop season. A split plot design with factorial arrangement and three replications were used. Treatments were timing of foliar urea application (a week before tasselling, mid anthesis and early milk stage), urea levels (zero (check), five and 7.5 g.lit-1) and two hybrids of corn (Sc 704) and forage sorghum (speed feed). The results indicated that the concentration of nitrogen had significant effect to increase forage protein and silage yield (correcting by 280 g.kg-1 of dry matter). The highest forage protein concentrations for both crops and silage yield were achieved with 7.5 g.lit-1 of urea application, but the silage yield of sorghum was more than that of corn. The results showed that urea spraying can effectively increase the fodder nitrogen and silage protein, respectively, with the least possible cost, and in this respect it has an important role in providing quality and environmental safe forage for producer and consumer, meanwhile the adverse effects of excessive use of nitrogen fertilizer are reduced.   </div

Simultaneous Selection for Yield and Yield Stability with Different Stability Statistics

For decreasing the effects of Genotype ×Environment (GE) interaction and having more precise selection, the yield and yield stability of selected lines should be evaluated simultaneously. YSi statistic is one of the applied methods for simultaneous selection of yield and yield stability. The objective of this study was to compare result of YSi statistic with other statistics approach such as S2i, CVi, S2di and R2i.Twenty hulless barley lines were evaluated in a randomized complete block design with three replications and in three locations (Neyshabour, Isfahan and yazd) during 2007-2009 crop seasons. Results of combined ANOVA indicated significant effects for Ggenotype ×Environment × year interaction (p= 0.01). Nine lines were selected by YSi method with overall mean of 5.89 t ha-1 grain yield. Overall mean yield of selected lines using only grain yield, yield plus environmental variance (or environmental coefficient of variation) and yield plus coefficient of regression and deviations from regression mean squares were 5.86, 6.01 and 5.85 t ha-1, respectively. Based to the LSD value (LSD=0.87 t ha-1, p=0.05), differences among mean yield (or different selection approaches) were not significant. As a result, with using the YSi statistic (with more emphasis on stability), the cultivar selection process can be done with more confidence