病原体必须逃过宿主免疫系统的重重防御，直至能够在宿主细胞内复制及扩散到其它细胞中，才算侵染成功。

To be successful, a pathogen must escape the many defenses of the host immune system until it can replicate and spread to another host.

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在无反应发生条件下进行固定化细胞内组分有效扩散系数测定时，常常要使细胞失去活性。

There exist different methods of inactivating cells which give a non-reaction-occurring condition under which the effective diffusivity of a substrate in the immobilized cell matrix is often measured.

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In general, inside of a cell molecules move by a process called diffusion.

总的来说,细胞内的分子通过扩散作用来移动

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