##    D = 1.7e-9 / (1e-12) #um^2/sec
##    consump_rate = (4.0e-17)#*(10**6) mols/cell/sec #umols/cell/sec
##    #This value later gets normalized using the 
##    #set the outside concentration
##     outside_c = 1.04e-4*10**6 #(umol/L) or uM
    #from War-tenberg et al., 2001

    D = 10.0 # um^2/sec
    consump_rate = 2.0e-20 #mol/cell/sec
    production_rate = 2.0e-20
##    outside_c = .1 #umol/L or uM
    outside_c = 0.0 #umol/L
    tnf = Gradient("TNF", D, 700.0, 700.0, 700.0, 15, 15, 15,
                 outside_c = outside_c)
    #add this to the simulation
    sim.add_gradient(tnf)
    lif = Gradient("LIF", D, 700.0, 700.0, 700.0, 15, 15, 15,
                 outside_c = outside_c)
    #add this to the simulation
    sim.add_gradient(lif)
##    while(True):
##        print(struct_path)
##        print(sim_base_path)
##        print(sim_id)
    #find the only file in the dir
    f = os.listdir(struct_path)
##    while(True):
##        print(struct_path + f[0])
    #then load this file
    #open the input structure file
    net = nx.read_gpickle(struct_path + f[0])