in find_BG_parameters.py : 

    N_A = 6.022140857e23
    x_LCC = 50000/N_A*1e15 # unit fmol
    V['x_LCC'] = x_LCC
    
    ## Define volumes
    V_myo = 34.4 # pL
    V_e = 5.182
    V['V_myo'] = V_myo
    V['V_e'] = V_e