In one embodiment, a memory that is delineated into transparent and non-transparent portions. The same source code and libraries are used for both modeling applications, allowing a user to see the impact of activating or deactivating specific software modules without affecting the actual node. A constraint component determines a constraint’s scope and variables upon which a constraint depends. The injectable formulation of polarized 129Xe gas is presented in small quantities of hyperpolarized 129Xe and can provide high-quality vasculature MRI images or NMR spectroscopic signals with clinically useful signal resolution or intensity.