Regex to change a word from lowercase to uppercase (same as substitution using "\U" in PCRE)

Hello,

I was wondering if anybody knew if there is a regex to change a word from lowercase to uppercase. 

Example:

Por favor, espera a que finalice la descarga.

I wanted to delete the "Por favor, "  and change the following word ("espera" in this case) to uppercase.

I was able to do it with the AutoHotkey regex flavor (PCRE, if I am not mistaken) with:

FIND WHAT: (Por favor, )(\w)

REPLACE WITH: \U\2

Where the "\U" turns the second capturing group (the "\w") into uppercase.

In fact, I think all I need is something that has the same effect as the  "\U" but for the Trados Studio regex flavor (I believe it is .NET, but I haven´t been able to either confirm this or find a good reference/tester website for it).

Any help much appreciated.