更糟糕的是这些电池会释放化学反应的副产品氢气，氢气会被身体吸收。

Unfortunately the batteries also gave off hydrogen gas as a chemical by-product, which diffused into the body.

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代谢组学研究代谢物，即人体细胞内持续进行的成千上万化学反应的副产品。

Metabolomics studies metabolites, the by-products of the hundreds of thousands of chemical reactions that continuously go on in every cell of the human body.

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每一次反应后产生的为数众多的副产品同样能得到充分地利用。

It makes use of the numerous by-products from each process.

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