Ex parte BENE - Page 7

          Appeal No. 95-3830                                                          
          Application No. 07/942,460                                                  

          deduced from the fresh and used liquid pressure measured by                 
          sensors 94 and 96, the above-quoted text of Shouldice et al.                
          merely suggests calculating the actual transmembrane pressure and           
          then comparing it with a predetermined transmembrane pressure to            
          see if it is too high.                                                      
               Based on the foregoing, we find that the examiner has                  
          equated determining the general transmembrane pressure to                   
          calculating an actual clearance of the artificial kidney for a              
          type of impurity.  That is erroneous.                                       
               Consistent with the appellant's specification (see pages 14-           
          15), regarding artificial kidneys the "clearance" for a type of             
          impurity is based on the concentration of substances in the                 
          blood, on the flow rates of blood and the dialysis liquid in the            
          exchanger, and on the membrane characteristics of the exchanger.            
          It concerns the efficiency for removing the type of impurity.               
          For instance, in the appellant’s preferred embodiment (pages 14-            
          15), conductivity of the dialysis liquid is measured, based on              
          which the concentration of ionized substances, predominantly                
          sodium, is calculated, and then through extrapolation and known             
          rules of correspondence the "clearance" of urea is determined               
          based in part on the characteristics of the exchanger and the               
          flow rates of the blood and dialysis liquid.  Alternatively, the            


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