Some of the most dangerous computer viruses have been spread by E-mail attachments, which are activated only upon opening.

Unlike previous games, power-ups are added to an inventory to be used when the player wishes, rather than activated immediately upon collection.

Satellite cells are normally activated upon injury or exercise.

It is activated by wetting, presumably upon administration, which requires moist contact.

They are often found within tissues where they can be activated by antigen-presenting cells upon infection.

In some cases, mines are automatically activated upon contact with the water.

"The fuse mechanism is activated upon impact," continued the officer.

"Sir, Project Colossus is completed, and can be activated upon your command."

I would like to begin by saying that the Community civil protection mechanism can be activated only upon a request by an affected country.

The provisions are activated upon a second conviction for a crime with a minimum sentence of three years imprisonment.