function [rrsrev,yfitrev,residualrev] = fitrev(CrevnoxEox,xlow,ylow,handle)
nox=1;
yfitrev= 0.08+(CrevnoxEox(1)./[1+10.^(nox*(CrevnoxEox(2)-xlow)/0.06)]);
residualrev = ylow-yfitrev;
rrsrev = sum(residualrev.^2);

set(gcf, 'DoubleBuffer','on');
set(handle,'ydata',yfitrev)
drawnow
pause(.08)