call drupal 7 api outside drupal

<?php
define('DRUPAL_ROOT', dirname(__FILE__));
chdir(DRUPAL_ROOT);
require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

global $user;

if ($user->uid) {
    print "Logged in";
} else {
    print "Logged out";
}

echo '<hr />';

$nid = 2;
$node = node_load($nid);
echo '<pre><code>'.print_r($node, true).'</pre>';
$node->field_last_check_result['und'][0]['value'] = 20;

node_save($node);