This will print as xml
header("Content-type: text/xml; charset=utf-8");
$html = '<obj><p>Figure 1. different (<italic>p</italic>'. htmlspecialchars('< 0.05).') .'</p></obj>';
// Or else if you need this, then uncomment below line
//$html = htmlspecialchars('<obj><p>Figure 1. different (<italic>p</italic>< 0.05).</p></obj>');
$doc = new DOMDocument("1.0","UTF-8");
@$doc->loadHTML($html);
echo ($doc->saveHTML());