<?php
$inp = '\u0412\u0440\u0435\u043c\u044f \u043f\u0440\u0438\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u0439. \u041a\u0430\u0440\u0442\u043e\u0447\u043d\u044b\u0435 \u0432\u043e\u0439\u043d\u044b. \u0424\u0438\u043d\u043';
$s = preg_replace('/\\\u0([0-9a-fA-F]{3})/','&#x\1;',$inp);
echo html_entity_decode($s, ENT_NOQUOTES, 'UTF-8');
?>