Thanks to all that replied, the problem is solved (I hope).  Special
thanks for the completeness (methodology etc.) of the information sent
by Research Diagnostics.

My apologies for the belated thank you note.  We actually started (not
at this institution) with the information rec'd on 7-28 but I have been
too busy to write until now.  

best regards,
Bob
Robert Schoonhoven
Laboratory of Molecular Carcinogenesis and Mutagenesis
Dept. of Environmental Sciences and Engineering
University of North Carolina
CB#7400
Chapel Hill, NC 27599
Phone 
office 919-966-6343
   Lab 919-966-6140
   Fax 919-966-6123 

Don't go around saying the world owes you a living; the world owes you
nothing; it was here first. 
Mark Twain [Samuel Langhornne Clemens] (1835-1910)