ABSTRACT
Aiming at the problem of the influence of preloading force on its mechanical response in soft tissue compression experiments, an elimination method of preloading force based on linear loading region is proposed. Unconfined compression experiments under a variety of different preloading forces are performed. The influence of the preloading force on the parameters of constitutive model is analyzed. In the preload phase, the mechanical response of the soft tissue is taken as a linear model. The preloading force is eliminated by taking the preloading phase into account throughout the response process. According to five different preloading forces of the unconfined compression experiments, the elimination method is validated with two different constitutive models of soft tissue, and the error between the models obtained by the preloading force elimination method and the traditional method with the experimental results is compared. The results show that the error obtained by preloading force elimination method is significantly smaller than the traditional method. The preloading force elimination method can eliminate the influence of preloading force on mechanical response to a certain extent, and constitutive model parameters which are closer to the true properties of soft tissue can be obtained.
Subject(s)
Elasticity , Linear Models , Models, Biological , Pressure , Stress, MechanicalABSTRACT
Objective To evaluate the effectiveness of several methods in eliminating Mycoplasma contamination in cell culture of human hepatoma-derived cell line C3A. Methods PCR was performed to detect the Mycoplasmas contamination in cell cultures. The contaminated samples were treated by ciprofloxa-cin, heating, Plasmocure or co-culturing with macrophages. Transmission electron microscope ( TEM) and Q-PCR were used to comparatively analyze the cell morphology and gene expression before and after Plas-mocure treatment. Results Plasmocure succeeded in eliminating Mycoplasma contamination, while cipro-floxacin showed temporary efficacy. Heating and co-culturing with macrophages failed to eliminate Mycoplas-ma contamination. No Mycoplasma contamination in the Plasmocure-treated group was observed under TEM and the expression of ALB, TF and CYP3A4 genes were higher than the genes expressed in the contaminated group (P<0. 01). Conclusion Plasmocure treatment was effective in eliminating Mycoplasma contamina-tion in cell culture. Moreover, the cell morphology and gene expression in Plasmocure-treated group were re-stored to normal.