突变致癌学说将化学致癌过程分为启动（initiation）、促进（promotion）和演变（progression）3个阶段。 启动阶段是致癌物直接作用于DNA初级序列，引起基因突变，使多个或少量细胞发生功能永久性的、不可逆的遗传性改变。具有这种作用的物质成为启动剂（initiator）。
结论桦木尘提取液可能为一启动剂，桦木尘水提取液的致癌性强于有机提取液。
Conclusion Both extracts of birch wood dust may be initiators, and carcinogenic effect of the water extract is stronger than that of the organic extract.
结论CSS和CH单独作用均为肿瘤启动剂；当二者联合作用时可协同启动肿瘤的发生。
Conclusion Both CSS and CH may act as initiator in carcinogenesis, and may synergistically initiate tumors when CSS and CH were exposed simultaneously.
对于还没有企业数据质量计划的组织，这可能是启动一个企业数据质量计划的催化剂。
This may be a catalyst for initiating an enterprise data quality initiative in the organization if one does not already exist.
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