If permitted measures fail, the operator may use a synthetic substance not included in the National List.

如果上述允许的措施无效，操作者可以使用全美允许物质列表以外的合成物质。

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Last week the issue was some leather cured with a known teratogenic substance, synthetic Nirret or something just as illegal that's still used in third world tanning.

上礼拜的问题是，部分皮革硫化时使用了致畸物质，某种非法但仍在第三世界用来硝制皮革的合成物质。

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"Food additive" means any synthetic compound or natural substance put into food to improve its quality, colour, fragrance or taste, or for the sake of preservation or processing.

食品添加剂：指为改善食品品质和色、香、味，以及为防腐和加工工艺的需要而加入食品中的化学合成或者天然物质。

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The researchers fired a beam of calcium ions, each containing 20 protons, into a target of californium, a highly radioactive synthetic substance with 98 protons.

ECONOMIST: Nuclear physics: Magical shell game | The

The faded, vintage-inspired logos give items the look of being around for decades while the silhouettes and fabric content have the style and substance that is in sharp contrast to the acres of brightly colored synthetic pieces found in most campus shops.

FORBES: Why American Eagle Makes the Back-to-School Grade