RESUMO
Objective To simulate the dynamic procedure of bullet damage to the three-dimensional(3D) finite element(FE) model of mandible from different angle with computer-aided engineering.Methods A mandible was scanned by thin-layer CT,and then CT images were analyzed and managed with Dicom standard and Mimics software.At the same time,a simulation of the 3D FE model penetrated by a 7.62-mm bullet was carried out through LS-DYNA software from different angle.Results A 3D FE model of human mandible was established with highly-identical geometric size,and the dynamic process of bullet damage to the model was successfully simulated.The results of this work indicated that the exit wounds in model tended to be larger than the entrances resulting from the same shot.Conclusion Thin-layer CT and Dicom standard can improve the efficiency of establishment of a more precise 3D FE model of mandible.The procedure of bullet damage to the mandible can be simulated by the finite element.
RESUMO
Objective To explore the effects of psoralen(PSO)and long-wave ultraviolet chemical therapy(PUVA) on cell apoptosis and expressions of FasL in HL-60,K562,and NB4 leukemia cells.Methods The cells were taken as the studying objects and their apoptosis ratios,ultrastructure changes and the expressions of FasL were detected in or- der to observe the effects of PSO extracted from Chinese medicine and ultraviolet at 360 nm on human leukemia cells.The factor design and analysis of variance were used to analyze the interaction among the factors.Results(1)PSO,UVA and PUVA all induced the apoptosis and the effects of PUVA were stronger than the other two.(2)Obvious changes of ultra- structure of leukemia cells were found under electron microscope after treatment with PUVA.(3)PSO,UVA and PUVA down-regulated FasL gene and protein expression levels,and the effects of PUVA are the strongest.Conclusion PUVA can induce the apoptosis of human leukemia cells and its effects are the strongest.One of the pathway of PUVA to induce apoptosis is by down-regulating the expression of FasL gene.