Impact of vasopressin analogues on the gut mucosal microcirculation

Given the controversial experimental and clinical data reported in the literature, up to now it is rather difficult to draw a definitive conclusion on the effects of V1 agonists on splanchnic haemodynamics. Nevertheless, it must be underscored that most of the experimental studies assessing the effects of low dose V1 agonist infusion in hyperdynamic models did not demonstrate any detrimental effect on splanchnic haemodynamics both at macro- and microcirculatory levels. Interestingly, all the reported studies focused on macro- and microcirculatory haemodynamics, while only some also addressed the local oxygenation and metabolism. In clinical studies in patients with septic shock, data are accumulating regarding the absence of clinically relevant side effects in the splanchnic region when vasopressin is used, but conversely little is known about the safety of terlipressin, mainly because of the small number of patients studied. Thus, the absence of clinically harmful effect does not exclude covert splanchnic ischaemia, which may counterbalance the beneficial systemic effects

CFD-based Analysis & Correlation Development for a Novel Multi-furcating Heat Exchanger for High Temperature, High Pressure Applications

The thermal efficiency of indirectly heated power cycles such as supercritical carbon dioxide (sCO2) closed Brayton cycles are typically limited by their heat exchangers (HXs), which require high heat transfer effectiveness while operating for tens of thousands of hours under high temperature (\u3e800°C) and pressure (\u3e80 bar) conditions. Previous literature has shown that the use of nature-inspired furcating flow channels represents an exciting opportunity to improve HX thermal-hydraulic performance. In this paper, we analyze the novel multi-furcating HX manifold concept, that was previously shown experimentally to reduce HX volume and mass compared to a baseline oil cooler by 50% and 67%, respectively. Computational fluid dynamics (CFD) simulations are utilized to analyze thermal-hydraulic performance and fluid flow development. CFD-based correlations of Nusselt number and friction factor are developed for performance prediction of a full, additively manufactured HX. The developed Nusselt number and friction factor correlations predict unit cell thermal-hydraulic performance within ±3% and ±5% for all simulated Reynolds numbers, respectively. The full HX would enable increased thermal efficiency of indirectly heated power cycles to reduce both energy consumption and emissions while also allowing opportunities in advanced aerospace applications