* There appears to be a redundant space right after the opening parenthesis, and a missing space just before the seconds parameter ;)
* No need for double quotes as string delimiter, so I'd switch them for single quotes (which are, in fact, faster as PHP will not parse them for variables)
* Personally, I'm no big fan of using ` as regex delimiter (I'd go for the ubiquitous /)

-- yes, I'm a whiner ;)