[ Eq(Derivative(x1, t), k25*x2 + k42*x12 + k40*x10 - (k10*x3*x1 - k10*k12*x5 + k14*x4*x1 - k15*x6)), Eq(Derivative(x2, t), k23*x6 - (k25*x2 + k30*x11*x2 - k31*x12 + k33*x9*x2 - k34*x10)), Eq(Derivative(x3, t), (-1)*(k6*x3*Piecewise((k2/(1 + exp((-80)*(t - k3 - 1/20))), And(Lt(t, k3 + 3/20), Ge(t, k3))), (k2, Ge(t, k3 + 3/20)), (0, True)) - k6*k8*x4 + k10*x3*x1 - k10*k12*x5)), Eq(Derivative(x4, t), k6*x3*Piecewise((k2/(1 + exp((-80)*(t - k3 - 1/20))), And(Lt(t, k3 + 3/20), Ge(t, k3))), (k2, Ge(t, k3 + 3/20)), (0, True)) - k6*k8*x4 + k23*x6 - (k14*x4*x1 - k15*x6)), Eq(Derivative(x5, t), k10*x3*x1 - k10*k12*x5 - (k17*Piecewise((k2/(1 + exp((-80)*(t - k3 - 1/20))), And(Lt(t, k3 + 3/20), Ge(t, k3))), (k2, Ge(t, k3 + 3/20)), (0, True))*x5 - k17*k19*x6)), Eq(Derivative(x6, t), k14*x4*x1 - k15*x6 - k21*x6 + k17*Piecewise((k2/(1 + exp((-80)*(t - k3 - 1/20))), And(Lt(t, k3 + 3/20), Ge(t, k3))), (k2, Ge(t, k3 + 3/20)), (0, True))*x5 - k17*k19*x6 - k23*x6), Eq(Derivative(x7, t), k21*x6), Eq(Derivative(x8, t), 1/(k54*3011/5)/(1/(k54*k55))*(k44*x9*k4/(k45/(1/(k54*3011/5)/(1/(k54*k55))) + k4) + k47*x10*k4/(k48/(1/(k54*3011/5)/(1/(k54*k55))) + k4)) - k50*x8), Eq(Derivative(x9, t), k27*x11*x13 - k28*x9 + k40*x10 - (k33*x9*x2 - k34*x10)), Eq(Derivative(x10, t), k33*x9*x2 - k34*x10 + k36*x12*x13 - k36*k38*x10 - k40*x10), Eq(Derivative(x11, t), k42*x12 - (k30*x11*x2 - k31*x12 + k27*x11*x13 - k28*x9)), Eq(Derivative(x12, t), k30*x11*x2 - k31*x12 - (k36*x12*x13 - k36*k38*x10 + k42*x12)), Eq(Derivative(x13, t), 1/(k54*3011/5)/(1/(k54*k55))*(-1)*(k27*x11*x13 - k28*x9 + k36*x12*x13 - k36*k38*x10)) ]