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Organoids grow in vitro to reproduce structures and functions of corresponding organs in vivo. As diffusion delivers nutrients over only ∼200 µm, refreshing flows through organoids are required to avoid necrosis at their cores; achieving this is a central challenge in the field. Our general aim is to develop a platform for culturing micro-organoids fed by appropriate flows that is accessible to bioscientists. As organs develop from layers of several cell types, our strategy is to seed different cells in thin modules (i.e. extra-cellular matrices in stronger scaffolds) in standard Petri dishes, stack modules in the required order, and overlay an immiscible fluorocarbon (FC40) to prevent evaporation. As FC40 is denser than medium, one might expect medium to float on FC40, but interfacial forces can be stronger than buoyancy ones; then, stacks remain attached to the bottom of dishes. After manually pipetting medium into the base of stacks, refreshing upward flows occur automatically (without the need for external pumps), driven mainly by differences in hydrostatic pressure. Proof-of-concept experiments show that such flows support clonal growth of human embryonic kidney cells at expected rates, even though cells may lie hundreds of microns away from surrounding fluid walls of the two immiscible liquids.

Nowadays, immersion cooling-based battery thermal management systems have demonstrated their effectiveness in controlling the temperature of lithium-ion batteries. While previous scientific research has primarily concentrated on traditional dielectric fluids such as mineral oil, the current research investigates the effectiveness of the dielectric fluid FC-40. A three-dimensional Computational Fluid Dynamics model of an eight-cell 18650 battery system was constructed using ANSYS Fluent 19.2 to examine the effect of cooling fluids (air, mineral oil, and FC-40), velocity of flow (0.01 m/s to 0.15 m/s), discharge rate (1C to 5C), and inlet/outlet size (2.5 mm to 3.5 mm) on thermal efficiency as well as pressure drop. The findings indicate that employing FC-40 as the dielectric fluid significantly reduces the peak cell temperature, with an absolute decrease of 2.80 °C compared to mineral oil and 15.10 °C compared to air. Furthermore, FC-40 achieves the highest uniformity with minimal hotspot. On the other hand, as the fluid velocity increases, the maximum temperature of the battery drops, reaching a minimum of 26 °C at a velocity of 0.15 m/s. Otherwise, at lower flow velocities, the pressure drop remains minimal, thereby reducing the pumping power consumption. Additionally, increasing the inlet and outlet diameter of the fluid directly improves cooling uniformity. Consequently, the temperature dropped by up to 4.3%. Finally, the findings demonstrate that elevated discharge rates contribute to increased heat dissipation but adversely affect the efficiency of the thermal management system. This study provides critical knowledge for the enhancement of battery thermal management systems based on immersion cooling using FC-40 as a dielectric.

A systematic evaluation of the selection criteria of non-aqueous phases in two liquid phase bioreactors (TLPBs), also named two-phase partitioning bioreactors (TPPBs), was carried out using the biodegradation of α-pinene by Pseudomonas fluorescens NCIMB 11671 as a model process. A preliminary solvent screening was thus carried out among the most common non-aqueous phases reported in literature for volatile organic contaminants biodegradation in TLPBs: silicon oil, paraffin oil, hexadecane, diethyl sebacate, dibutyl-phtalate, FC 40, 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMS), and 2,2,4,4,6,8,8-heptamethylnonane (HMN). FC 40, silicone oil, HMS, and HMN were first selected based on its biocompatibility, resistance to microbial attack, and α-pinene mass transport characteristics. FC 40, HMS, HMN, and silicone oil at 10% (v/v) enhanced α-pinene mass transport from the gas to the liquid phase by a factor of 3.8, 14.8, 11.4, and 8.6, respectively, compared to a single-phase aqueous system. FC 40 and HMN were finally compared for their ability to enhance α-pinene biodegradation in a mechanically agitated bioreactor. The use of FC 40 or HMN (both at 10% v/v) sustained non-steady state removal efficiencies (RE) and elimination capacities (EC) approximately 7 and 12 times higher than those achieved in the system without an organic phase, respectively. In addition, preliminary results showed that P fluorescens could uptake and mineralize α-pinene directly from the non aqueous phase. (PUBLICATION ABSTRACT)