cat loop core

<div class="panel" id="cat-item-<?php echo $cat->term_id; ?>">
            <?php query_posts('category_name='.$cat->slug.'&posts_per_page='); ?>
               if(have_posts()) :
            <h1 class="page-title"><?php $catid = $cat->term_id; $cat_family = array_reverse(explode(',',get_category_parents($catid,false,','))); echo ($cat_family[2]) ? $cat_family[2].' ' : '';?><br />
                    <span class="bigga">
                        <?php echo $cat->name; ?>
                    </span></h1>

            <?php while (have_posts()) : the_post(); ?>
            <?php get_template_part( 'content' ); ?>
            <?php endwhile; // end of the loop. ?>
            <?php endif; ?>
       <?php wp_reset_query(); ?>
         </div>