Figure 1

Calculated oxygen concentration for three islets (with diameters of ɸ = 100, 150, and 200 μ m) in standard culture conditions after steady state conditions have been reached ( h = 1 mm assumed) presented as a colour-coded surface with red corresponding to higher and blue to lower concentrations. Green arrows represent oxygen flux. Areas with oxygen concentrations below a critical value ( < 10^-4 mol·m^-3), where hypoxia is predicted to result in necrosis after a sufficiently long exposure, are coloured in white.