In some cases the specific change triggers a signal - the folded or square position may activate some other enzyme, or open a channel in a cell.

在某些情况下特别的变化能触发一个信号——折叠的或方形的状态将激活一些其他的酶，或在细胞中打开一个通道。

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You can now easily activate a 30-second replay, for example, and you can change the replay speed (half-speed and double-speed).

你现在可以激活30秒的回放功能，你也可以改变回放的速度(半速和两倍速度)。

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A change was made so the extension showed just the view's title and icon, but it didn't activate the bundle that contributed the extension until the end user actually tried to view it.

后来把改扩展改为只显示视图的标题和图标，直到终端用户真的尝试看该视图时，才激活加入到扩展中的那个包。

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One application Sotzing has been working on is meat packaging with a built-in tongue that can taste the first signs of spoilage and activate a color change as a warning.

FORBES: Safer And Guilt-Free Nano Foods

It used a flashlight-like device to activate photo cells on the television set to change channels.

FORBES: Remembering Eugene Polley, an Inventor of the TV Remote

In iA mode users can automatically activate a suite of technologies to enhance photos without adjusting settings every time conditions change.

ENGADGET: Panasonic's Lumix line gets a lot more crowded