Errata In the list of patents which expired on October 18, 2000, due to failure to pay maintenance fees, listed in the Official Gazette of December 19, 2000, Patent Number 5,154,712 should not have appeared since the fee was timely paid. In the list of patents which expired on January 10, 2001, due to failure to pay maintenance fees, listed in the Official Gazette of March 13, 2001, Patent Number 5,591,191 should not have appeared since the fee was timely paid. In the list of patents which expired on January 10, 2001, due to failure to pay maintenance fees, listed in the Official Gazette of March 13, 2001, Patent Number 4,797,861 should not have appeared since the fee was timely paid. In the list of patents which expired on December 27, 2000, due to failure to pay maintenance fees, listed in the Official Gazette of February 27, 2001, Patent Number 5,172,498 should not have appeared since the fee was timely paid. In the list of patents which expired on September 17, 1997, due to failure to pay maintenance fees, listed in the Official Gazette of November 25, 1997, Patent Number 5,245,177 should not have appeared since the fee was timely paid. In the list of patents which expired on December 10, 1997, due to failure to pay maintenance fees, listed in the Official Gazette of February 17, 1998, Patent Number 5,268,170 should not have appeared since the fee was timely paid. In the list of patents which expired on October 22, 1997, due to failure to pay maintenance fees, listed in the Official Gazette of December 30, 1997, Patent Number 5,253,498 should not have appeared since the fee was timely paid.