[ Eq(Derivative(x1, t), ((-1)*k33*x12*x1*k26 + 1*(k12*166112956810631/100000000000000000*x2*x6 + (-k12*k13*x1))*k26)/k26),
  Eq(Derivative(x2, t), (1*k33*x12*x1*k26 + (-1)*(k12*166112956810631/100000000000000000*x2*x6 + (-k12*k13*x1))*k26 + (-1)*k27*(k22*166112956810631/100000000000000000*x13*166112956810631/100000000000000000*x2 + (-k22*k23*166112956810631/100000000000000000*x5))*1*1/k1)/k27),
  Eq(Derivative(x3, t), (-1)*k26*(Piecewise((581/1000*k3*((-1) + exp((k2 + (-x7))*1/k2)), Lt(x7, k2)), (0, True)) + Piecewise((k4*exp(-(t + (-k5))*1/k6), Gt(t, k5)), (0, True)))*x3/k26),
  Eq(Derivative(x4, t), 0),
  Eq(Derivative(x5, t), 1*k27*(k22*166112956810631/100000000000000000*x13*166112956810631/100000000000000000*x2 + (-k22*k23*166112956810631/100000000000000000*x5))*1*1/k1/k27),
  Eq(Derivative(x6, t), ((-1)*k30*x6*x12*k26 + (-1)*(k12*166112956810631/100000000000000000*x2*x6 + (-k12*k13*x1))*k26 + 1*k26*(Piecewise((581/1000*k19*((-1) + exp((k18 + (-x6))*1/k18)), Lt(x6, k18)), (0, True)) + Piecewise((k15*exp(-(t + (-k16))*1/k17), Gt(t, k16)), (0, True)))*x7)/k26),
  Eq(Derivative(x7, t), (1*k26*(Piecewise((581/1000*k3*((-1) + exp((k2 + (-x7))*1/k2)), Lt(x7, k2)), (0, True)) + Piecewise((k4*exp(-(t + (-k5))*1/k6), Gt(t, k5)), (0, True)))*x3 + (-1)*k26*(Piecewise((581/1000*k19*((-1) + exp((k18 + (-x6))*1/k18)), Lt(x6, k18)), (0, True)) + Piecewise((k15*exp(-(t + (-k16))*1/k17), Gt(t, k16)), (0, True)))*x7)/k26),
  Eq(Derivative(x8, t), (1*k30*x6*x12*k26 + 1*k33*x12*x1*k26)/k26),
  Eq(Derivative(x9, t), 0),
  Eq(Derivative(x10, t), 0),
  Eq(Derivative(x11, t), (-1)*k26*(k31*x11*k36*Piecewise((exp(-(t + (-k9))*1/k10), Gt(t, k9)), (0, True)) + (-k32*x12))/k26),
  Eq(Derivative(x12, t), 1*k26*(k31*x11*k36*Piecewise((exp(-(t + (-k9))*1/k10), Gt(t, k9)), (0, True)) + (-k32*x12))/k26),
  Eq(Derivative(x13, t), (1*k30*x6*x12*k26 + 1*k33*x12*x1*k26 + (-1)*k27*k35*(166112956810631/100000000000000000*x13 + (-k34))*1*1/k1 + (-1)*k27*(k22*166112956810631/100000000000000000*x13*166112956810631/100000000000000000*x2 + (-k22*k23*166112956810631/100000000000000000*x5))*1*1/k1)/k27) ]