function [Td] = find_Td (t,x)
% this function is used to find the time cPARP reaches half its maximum
% concentration

% t is the time vector corresponding to x
% x is the reagent values at a given time.

% Td is the time of half maximum cPARP concentration [s]
x = x/(max((x)));
Td = 0;
for i = 1:length(x)-1
    if x(i)<.5 && x(i+1)>.5
        Td = (t(i+1)-t(i))/(x(i+1) - x(i))*(.5 - x(i)) + t(i);
    elseif x(i) == .5
        Td = t(i);
    end
end

end