 Cadmium can be used to block calcium channels in chicken neurons . Analytical methods for the determination of cadmium in biological samples have been reviewed . 
 Cadmium can be used to block calcium channels in chicken neurons . Analytical methods for the determination of cadmium in biological samples <a href='been_done' title='1'><mark>have</mark></a> been reviewed . 
Cadmium can be used to block calcium channels in chicken neurons . Analytical methods fir the determination of cadmium in biological samples done been reviewed .