{ diff(x1, t) = (1*k23*k3*x1*piecewise(1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22, 1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22 > 0, 0) + (-1)*k23*k13*x7*x1*(1 + k14*x4)*x6^2/(x6^2 + k16^2))/k23,
  diff(x2, t) = (1*k23*2^k1*k13*x7*x1*x6^2/(x6^2 + k16^2)*(1 + k14*x4) + (-1)*k23*k8*x2)/k23,
  diff(x3, t) = (1*k23*k4*x3*piecewise(1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22, 1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22 > 0, 0) + (-1)*k23*k15*x7*x3*x6^2/(x6^2 + k16^2))/k23,
  diff(x4, t) = (1*k23*2^k1*k15*x7*x3*x6^2/(x6^2 + k16^2) + (-1)*k23*k9*x4)/k23,
  diff(x5, t) = (1*k23*k12 + 1*k23*k5*x5*piecewise(1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22, 1 - (x7 + x2 + x1 + x4 + x3 + x5)/k22 > 0, 0) + (-1)*k23*k10*x5)/k23,
  diff(x6, t) = (1*k23*k11*x7*(x2 + x4) + (-1)*k23*k7*x6 + (-1)*k23*x8 + 1*k23*k21)/k23,
  diff(x7, t) = (1*k23*k2*x7*(1 - x7/k18) + (-1)*k23*k6*x7*x2)/k23,
  diff(x8, t) = 0/k23 }