Calm nerd ragers?

So after a particularly spirited whiner i was just wondering what methods people use to try and stop their teamates from tilting so much? In this case a top laner was losing and raging at the jungle, freaking out about ganks. Of course the jungle can't ALWAYS be there so he still died often. When he began to go full nerd rage i just said 'dude calm down' and he lost it even more. I muted him to avoid any more frustrations but i could hear my team freaking out at him as well. It was lots of poor plays and of course my teammates began doing more poorly as they spent more time keyboard warrioring. Even here on boards it seems people go full rage over things, whether they are correct on an issue or not they seem to simply want to bitch and infuriate others. So i ask other players, what is your method (besides the mute button that i favor) to try and calm down a teammate?