应用Percoll分离纯化组织工程用肌卫星细胞

目的 探讨应用改良Percoll非连续密度梯度离心法分离纯化培养组织工程用肌卫星细胞。方法 分别采用差速贴壁法和Percoll非连续密度梯度离心法进行兔肌卫星细胞的原代培养、光镜及扫描电镜检查细胞形态，通过免疫细胞化学染色方法鉴定培养细胞纯度，噻唑蓝法测定细胞生长曲线。结果 差速贴壁法所得细胞纯度为30％．40％，Percoll非连续密度梯度离心法所得细胞纯度在90％以上，两种方法光镜及电镜检查均符合卫星细胞形态，细胞生长曲线显示细胞生长状况良好。结论 应用Percoll非连续密度梯度离心法可以得到高纯度的肌卫星细胞，可以作为组织工程用种子细胞的培养方法。

Damage Studies of Brittle-Ductile Transition in PP EPDM Blends

Damage zones of brittle-ductile (B-D) transition in PP/EPDM blends are studied in this paper. The contribution of crazing and shear yielding zones in damage zones to energy dissipation of blends was measured with computer image analysis (CIA) and the transition of shear yielding zone (A_(sh)) with rubber volume fraction (V_f) was also manipulated. Results showed that the B-D transition of impact strength of blends corresponded to the fracture mechanism in PP/EPDM blends, from matrix crazing to matrix shear yielding. In addition, two new parameters, density of energy dissipation for crazing zone (F_(cz)) and for shear yielding zone (F_(sh)), are first obtained in this paper. The value of F_(sh) is about four times larger than that of F_(cz) for PP/EPDM blends, which confirmed that the matrix shear yielding is a more effective way of energy dissipation in blends.