Cost of Using Laser Powder Bed Fusion to Fabricate a Molten Salt-to-Supercritial Carbon Dioxide Heat Exchanger for Concentrating Solar Power.

Advances in manufacturing technologies and materials are crucial to the commercial deployment of energy technologies. We present the case of concentrating solar power (CSP) with molten salt (MS) thermal storage, where low-cost, high-efficiency heat exchangers (HXs) are needed to achieve cost competitiveness. The materials required to tolerate the extreme operating conditions in CSP systems make it difficult or infeasible to produce them using conventional manufacturing processes. Although it is technically possible to produce HXs with adequate performance using additive manufacturing, specifically laser powder bed fusion (LPBF), here we assess whether doing so is cost-effective. We describe a process-based cost model (PBCM) to estimate the cost of fabricating a MS-to-supercritical carbon dioxide HX using LPBF. The PBCM is designed to identify modifications to designs, process choices, and manufacturing innovations that have the greatest effect on manufacturing cost. Our PBCM identified HX design and LPBF process modifications that reduced projected HX cost from $750 per kilo-Watt thermal (kW-th) ($8/cm3) to $350/kW-th ($6/cm3) using currently available LPBF technology, and down to $220/kW-th ($4/cm3) with improvements in LPBF technology that are likely to be achieved in the near term. The PBCM also informed a redesign of the HX design that reduced projected costs to $140-160/kW-th ($3/cm3).

Analysis on heat transfer performance of coaxial borehole heat exchanger in a layered subsurface with groundwater.

In the realm of ground source heat pump (GSHP) installations, the operational efficiency of borehole heat exchangers (BHEs) is heavily dependent on the complex configurations of geological formations, including soil stratification and the movement of underground water. Our research investigated the influences of ground structure characteristics on the heat transfer performance of coaxial BHEs. A coaxial borehole heat exchanger with a three-dimensional design was constructed, setting a typical geology from the Xiong'an New Region as the boundary condition. The homogenous model with equivalent physical properties overpredicted the water temperature exiting the coaxial BHE in the stratified ground with groundwater advection by 0.2 °C, while underpredicted the heat transfer rate by 10.8 % for the 24-h period; There exists an optimal inlet flow velocity to balance the heat injection and enhanced heat transfer for the optimal heat transfer rate, which was 0.4 m/s in this study; The increase of groundwater advection velocity decreased the outlet temperature by 0.5 %, enhanced the heat transfer per meter by 15.5 % and contributed to a smaller thermal influence radius during the 24-h period. This will contribute to the design of coaxial BHEs in complex geological structure.

Role of NHERF1 in MicroRNA Landscape Changes in Aging Mouse Kidneys.

MicroRNAs (miRNAs) play important roles in the regulation of cellular function and fate via post-transcriptional regulation of gene expression. Although several miRNAs are associated with physiological processes and kidney diseases, not much is known about changes in miRNAs in aging kidneys. We previously demonstrated that sodium hydrogen exchanger 1 (NHERF1) expression regulates cellular responses to cisplatin, age-dependent salt-sensitive hypertension, and sodium-phosphate cotransporter trafficking. However, the mechanisms driving these regulatory effects of NHERF1 on cellular processes are unknown. Here, we hypothesize that dysregulation of miRNA-mediated gene regulatory networks that induce fibrosis and cytokines may depend on NHERF1 expression. To address this hypothesis, we compared miRNA expression in kidneys from both male and female old (12-18-month-old) and young (4-7-month-old) wild-type (WT) and NHERF1 knockout (NHERF1-/-) mice. Our results identified that miRNAs significantly decreased in NHERF1-/- mice included miR-669m, miR-590-3p, miR-153, miR-673-3p, and miR-127. Only miR-702 significantly decreased in aged WT mice, while miR-678 decreased in both WT and NHERF1-/- old versus young mice. miR-153 was shown to downregulate transcription factors NFATc2 and NFATc3 which regulate the transcription of several cytokines. Immunohistochemistry and western blotting revealed a significant increase in nuclear NFATc2 and NFATc3 in old NHERF1-/- mice compared to old WT mice. Our data further show that expression of the cytokines IL-1ß, IL-6, IL-17A, MCP1, and TNF-α significantly increased in the old NHERF1-/- mice compared to the WT mice. We conclude that loss of NHERF1 expression induces cytokine expression in the kidney through interactive regulation between miR-153 and NFATc2/NFATc3 expression.

Design of an injera baking system using parabolic trough solar collectors at Mekelle University cafeteria.

Injera baking poses a significant energy demand and strain on the national grid, requiring temperatures of 180-220 °C with traditional clay Mitads. This study aimed to design a solar thermal system to replace electrical baking energy at the Mekelle University student cafeteria. The system, designed for baking 11,000 Injera within a 6-h daily operation, comprises 92 Anodized aluminum plate Mitads heated by hot oil from an oil gallery, stored in a hot oil storage unit, and recharged via a parabolic trough solar collector. A heat exchanger and thermal storage system ensure efficient heat transfer and storage. Computational Fluid Dynamics (CFD) and Soltrace analyses were conducted to assess temperature distribution on the baking pan and oil gallery surfaces, as well as solar thermal heat flux. Results revealed a heating capacity of 2.11 kW per Mitad, meeting the required capacity, and a system energy consumption of 1216.5 MJ per hour, achieving a thermal efficiency of 57.4 %. Baking Injera at higher temperatures, enabled by a uniform temperature distribution, yielded uniformly textured Injera with an optimal number of eye bubbles and prevented sticking to the Mitad. Consequently, this design offers a viable alternative for the energy-intensive application at the Mekelle University student cafeteria, providing valuable insights for future solar thermal Injera baking system designers.

Numerical investigation of MHD mixed convection in an octagonal heat exchanger containing hybrid nanofluid.

Nowadays, the advancement of heat transmission for the heat exchanger device is an important field of research for many researchers. In this work, a numerical study has been conducted to investigate the thermal performance of a mixed convective flow through the octagonal heat exchanger covered by hybrid nanofluid (Cu-TiO2-H2O). A magnetic field has been introduced inside the cavity to investigate the mixed convective hydrodynamics heat flow characteristics. The nanofluid cores absorb/release energy to manage heat transmission by increasing or decreasing inside the cavity domain as the host fluid and dispersed hybrid nanofluid circulate within the cavity. After transforming the governing equations into a generalized, non-dimensional formulation, the finite element approach is utilized to solve the associated equations. Additionally, response surface methodology is also applied to test the responses of the associated factors. Heat transport was examined in relation to the effects of nanofluids fusion temperature, boundary wall properties, Reynolds number, Hartmann number and nanoparticle volume fractions. The outcomes of this study are analysed by measuring streamline profiles, isotherms, average Nusselt number, velocity profile, and 2D and 3D response surfaces of the computational domain. The underlying flow controlling parameters for instance Reynolds number (10 ≤ Re ≤ 200), Hartmann number (0 ≤ Ha ≤100), and nanoparticle volume fractions (0 ≤ Ï• ≤ 0.1), the influences have been considered. The findings also reveal that the thermal performance is being boosted due to augmentation of Re and ϕ, but reverse behavior is noticed for Ha. Furthermore, the response surfaces obtained from response surfaces methodology express that the Re and ϕ have shown positive influence, and Ha has shown negative influence on Nuav. Utilizing a hybrid nanofluid of Cu-TiO2-H2O increases the heat transfer capacity of water to 25.75 %. Moreover, the findings could guide to design of a mixed convective heat exchanger for industrial purposes.

Developmental Changes in the Excitation-Contraction Mechanisms of the Ventricular Myocardium and Their Sympathetic Regulation in Small Experimental Animals.

The developmental changes in the excitation-contraction mechanisms of the ventricular myocardium of small animals (guinea pig, rat, mouse) and their sympathetic regulation will be summarized. The action potential duration monotonically decreases during pre- and postnatal development in the rat and mouse, while in the guinea pig it decreases during the fetal stage but turns into an increase just before birth. Such changes can be attributed to changes in the repolarizing potassium currents. The T-tubule and the sarcoplasmic reticulum are scarcely present in the fetal cardiomyocyte, but increase during postnatal development. This causes a developmental shift in the Ca2+ handling from a sarcolemma-dependent mechanism to a sarcoplasmic reticulum-dependent mechanism. The sensitivity for beta-adrenoceptor-mediated positive inotropy decreases during early postnatal development, which parallels the increase in sympathetic nerve innervation. The alpha-adrenoceptor-mediated inotropy in the mouse changes from positive in the neonate to negative in the adult. This can be explained by the change in the excitation-contraction mechanism mentioned above. The shortening of the action potential duration enhances trans-sarcolemmal Ca2+ extrusion by the Na+-Ca2+ exchanger. The sarcoplasmic reticulum-dependent mechanism of contraction in the adult allows Na+-Ca2+ exchanger activity to cause negative inotropy, a mechanism not observed in neonatal myocardium. Such developmental studies would provide clues towards a more comprehensive understanding of cardiac function.

Numerical Investigation of Enhanced Heat Transfer with Micro Pin Fins in Heat Exchangers.

Pin-fin and flat-tube heat exchangers (PFFTHXs) offer a promising alternative to traditional louvered-fin and flat-tube heat exchangers (LFFTHXs), especially when used as evaporators. The streamlined structure of pin fins helps to effectively remove condensate and defrost water. In this study, we conducted a numerical analysis of 60 different pin-fin configurations across three pin diameters to enhance heat transfer in PFFTHXs. Our investigation focused on how pin pitch affects both airflow and heat transfer efficiency. The results show that a closer pin pitch increases both the heat transfer rate per unit area and the pressure drop for a given airflow velocity. We evaluated the overall performance of these configurations using the heat transfer rate per unit frontal area obtained at equivalent fan power levels. The analysis identified optimal configurations for each pin diameter, with the 0.2 mm diameter configuration demonstrating the highest heat transfer efficiency-this was on par with louvered fins but used fewer resources. This makes it an ideal choice for evaporative applications in PFFTHXs.

Effects of Dapagliflozin in Combination with Hydrochlorothiazide on Cardiac Remodeling in Rats with Heart Failure After Myocardial Infarction.

In addition to its antihypertensive and diuretic effects, hydrochlorothiazide also demonstrates additional cardioprotective properties; however, the existence of a synergistic interaction between dapagliflozin and hydrochlorothiazide remains unclear.To establish a rat model of heart failure for investigating the effects and mechanisms of dapagliflozin in combination with hydrochlorothiazide during early intervention, H9c2 cells were cultured to validate their in vitro efficacy. The combination group exhibits a synergistic improvement in hemodynamics, ejection fraction, and a reduction in plasma B-type natriuretic peptide concentration. This combination effectively decreases collagen volume fraction and the expression of collagen I and III, p47phox, p67phox, NF-κB p65, Bax, and caspase-3. The combination group demonstrates a synergistic effect in enhancing cardiac function, attenuating oxidative stress and inflammation. The in vitro effects of the combination were demonstrated in H9c2 cardiomyocytes. In addition, the combination exhibits a more pronounced inhibitory effect on NHE1 expression. The expression of NHE1 in H9c2 cells is inhibited by hydrochlorothiazide, thereby alleviating the consequences of NHE1 overexpression. The results of molecular docking and kinetic simulations indicate a strong binding affinity (-6.1 kcal/mol) between hydrochlorothiazide and NHE1, resulting in the formation of a stable conformation. This may elucidate the underlying mechanism responsible for the synergistic effects of drugs.The combination of dapagliflozin and hydrochlorothiazide has synergistic effects on improving cardiac function, oxidative stress, and inflammation in rats with heart failure. Hydrochlorothiazide binds to and inhibits the expression of NHE1, thereby enhancing dapagliflozin's inhibitory effect on NHE activity. This mechanism potentially elucidates its enhanced cardioprotective effects.

Heat transfer and friction factor analysis for tomato puree flowing in a concentric-tube heat exchanger.

The heat and momentum transfer of tomato puree through a concentric-tube heat exchanger over a range of generalized Reynolds number (0.05 < Re < 66.5) was experimentally and numerically analyzed. Thermophysical and rheological properties of tomato puree (12°Brix) were measured from 20 to 60°C. The velocity, pressure, and temperature were calculated using the computational fluid dynamics (CFD) software FLUENTTM with temperature-dependent transport properties. The thermal operation of the concentric-tube exchanger was satisfactorily predicted using CFD, indicating accurate measurement of tomato puree properties with temperature variations. A concordance was found between the calculated Fanning friction factor and generalized Reynolds with the experimental correlation. A modified Sieder-Tate correlation was established, which allows properly expressing the Nusselt number as a function of the Peclet number. Simple correlations for the mechanical work and the heat transfer rate as a function of the volumetric flow rate were derived. The thermal efficiency was high at low puree flow rates but decreased with higher rates. However, at high flow rates, ceased its decline, instead showing a slight improvement. The analysis confirmed higher heat transfer rates in the concentric-tube heat exchanger compared to a plain tube at low puree flow rates. The results offer valuable insights for assessing diverse operational conditions in dairy, beverage, sauce, and concentrated food industries. Additionally, they also enhance the analysis and design of concentric-tube heat exchangers. PRACTICAL APPLICATION: The knowledge of the rheological and hydrodynamical behavior of fluids in concentric-tube heat exchangers allows to explore a set of different operating conditions to improve the yield and effectiveness on the system heating/cooling design.

Experimental study on the impact of indoor unit airflow velocity on the performance of an automotive heat pump system with a suction line heat exchanger.

This study aimed to investigate the effect of changing the indoor unit air flow rate on the performance of an automobile heat pump with a suction line heat exchanger. Using a four-way valve, the automotive heat pump system was developed by reversing the refrigerant direction in the automobile air conditioning system, excluding the compressor. A suction line heat exchanger was added to the test system to enhance heat transfer between the liquid and suction lines of the automotive heat pump system. Performance comparisons were first performed for R134a and R1234yf by disabling the suction line heat exchanger. Then, the suction line heat exchanger was activated for R1234yf, and the tests were repeated. Performance comparisons were made for two different compressor speeds and three different indoor unit airflow speeds. It was found that using the heat exchanger in R1234yf operations improved the heating capacity, compressor discharge temperature and coefficient of performance by approximately 1.8 %, 5.1 % and 5.9 %, respectively. The heating capacity of the heat pump system using R134a, R1234yf, and R1234yf with the suction line heat exchanger was determined to be in the range of 2.46-3.29 kW, 2.35-3.04 kW, and 2.39-3.11 kW, respectively. An increase in the airflow speed of the indoor unit from 1.4 m s-1 to 3.2 m s-1 resulted in an average decrease of approximately 12.3 % in the compressor discharge temperature. In contrast, the heating capacity and coefficient of performance increased by approximately 11.8 % and 14.4 % on average, respectively, for R1234yf operations with the heat exchanger. This study revealed that by optimizing the air flow rate in the R1234yf heat pump system with a suction line heat exchanger, improvements in the heating capacity and coefficient of performance can be achieved, thus providing better thermal comfort in the passenger compartment.

Optimization of the thermal performance of a lobed triplex-tube solar thermal storage system equipped with a phase change material.

The thermal performance of a PCM-based triple-tube lobed heat exchanger storage system is here simulated and optimized, including performance improvements via lobed surfaces, Y-shaped fins, dispersed multi-walled carbon nanotubes, and metal foams, to be used in combination, or singly. Such computations are done with the finite volume method under different operating conditions. The reason behind this study is to look for solutions to improve the poor thermal performance of phase change materials (PCMs) as thermal energy storage materials, that limits their compactness and instantaneous heat stored/released. This is the first time that a throughout analysis of this aspect is presented. The result showed that higher modified Stefan number allow to improve melting time of a 50.88 %. The inclusion of lobes and fins resulted in a reduction of roughly 30.54 % in time needed for melting completion, compared to straight tubes. This reduction increases to 74.26 % when lobes are combined with both nanoparticles and metal foam, and to 73.60 % with just foam. The best solution also provides a 228.34 W mean heat rate. This study becomes an option to design tube-in-tube energy storage systems, where the best improvement is achieved by considering a lobed surface together with nano/PCM and foam, whereas the highest enhancement comes from using a metal foam.

Anti-Frosting and Defrosting Fins with Hierarchical Interlocking Structure for Enhancing Energy Utilization Efficiency of Heat Exchanger.

Air conditioners, being an indispensable component of contemporary living, consume a significant amount of electricity every year. The accumulation of frost, dust, and water on the fins surface hinders the efficiency of the heat exchange process, thereby reducing the effectiveness of the air conditioning system. To address these limitations, this paper proposes a large-scale and cost-effective method combining compression molding, chemical etching, and spray coating to fabricate aluminum fins (HMNA) with hierarchical interlocking structures. The HMNA exhibits outstanding durability, passive and active anti-icing, anti-frosting and defrosting, and self-cleaning capabilities associated with the robust super-hydrophobicity. The hierarchical interlocking structure effectively enhances the physical and environmental durability of the HMNA. Most significantly, the frost time of the HMNA fins assembled heat exchanger is significantly delayed by ≈700% compared to the traditional Al fins heat exchanger, while the frost layer thickness is reduced by ≈75%. This greatly reduces the frequency with which the defrosting cycle is started, thus effectively improving the efficiency of the air conditioning system. The proposed method for economical and mass production of the HMNA fins can be an excellent candidate for the development of low energy consumption air conditioning system.

Bufalin CaCO3 Nanoparticles Triggered Pyroptosis through Calcium Overload via Na+/Ca2+ Exchanger Reverse for Cancer Immunotherapy.

Bufalin is a promising active ingredient in traditional Chinese medicine but has shown limited anticancer applications due to its toxicity. Here, we report BCNPs@gel, a bufalin-containing CaCO3 nanoparticle hydrogel, for enhancing cancer treatment through inducing cellular pyroptosis. Under the tumor microenvironment's low pH conditions, bufalin and Ca2+ are released from the delivery system. Bufalin serves as a direct anticancer drug and a Na+/K+-ATPase inhibitor by forcing the Na+/Ca2+ exchanger to reverse its function, which transfers Ca2+ into cytoplasm and ultimately causes Ca2+ overload-triggered pyroptosis. Meanwhile, we found that bufalin can upregulate PD-L1 in tumor cells. In combination with the PD-1 antibody, the delivery system showed a greater performance during the cancer treatment. BCNPs@gel enhances antitumor efficiency, reduces systemic side effects, extends antitumor mechanism of bufalin, and provides new strategies for inducing pyroptosis and calcium overload in cancer immunotherapy via Na+/K+-ATPase inhibitor. This work provides an application model for numerous other traditional Chinese medicine ingredients.

Enhanced Late INa Induces Intracellular Ion Disturbances and Automatic Activity in the Guinea Pig Pulmonary Vein Cardiomyocytes.

The effects of enhanced late INa, a persistent component of the Na+ channel current, on the intracellular ion dynamics and the automaticity of the pulmonary vein cardiomyocytes were studied with fluorescent microscopy. Anemonia viridis toxin II (ATX- II), an enhancer of late INa, caused increases in the basal Na+ and Ca2+ concentrations, increases in the number of Ca2+ sparks and Ca2+ waves, and the generation of repetitive Ca2+ transients. These phenomena were inhibited by eleclazine, a blocker of the late INa; SEA0400, an inhibitor of the Na+/Ca2+ exchanger (NCX); H89, a protein kinase A (PKA) inhibitor; and KN-93, a Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor. These results suggest that enhancement of late INa in the pulmonary vein cardiomyocytes causes disturbance of the intracellular ion environment through activation of the NCX and Ca2+-dependent enzymes. Such mechanisms are probably involved in the ectopic electrical activity of the pulmonary vein myocardium.

Experimental study of dual-cycle thermal management system for engineering radiator.

With the increasing demand for heat dissipation of engineering vehicles, a dual-cycle cooling system is introduced in this paper to prevent the adverse effects of engineering vehicles' equipment when operating at the overheating temperature. The performance of the new system is analyzed through tests, and the results show that the dual-cycle cooling system can meet the thermal balance requirements of the engineering vehicle during the shovel operation. Compared with the traditional cooling system, the new cooling system improved performance in terms of volume, engine energy consumption and working oil efficiency. The oil consumption of a wheel loader using the dual-cycle cooling system is reduced by 1% per hour, and the temperature of its transmission oil and hydraulic oil is reduced by more than 10 °C. The new cooling system has bright future in energy saving and emission reduction of engineering vehicles.

Transformation of Cu2O into Metallic Copper within Matrix of Carboxylic Cation Exchangers: Synthesis and Thermogravimetric Studies of Novel Composite Materials.

In order to systematize and expand knowledge about copper-containing composite materials as hybrid ion exchangers, in this study, fine metallic copper particles were dispersed within the matrix of a carboxyl cation exchanger (CCE) with a macroporous and gel-type structure thanks to the reduction of Cu2O particles precipitated within the matrix earlier. It was possible to introduce as much as 22.0 wt% Cu0 into a gel-type polymeric carrier (G/H#Cu) when an ascorbic acid solution was used to act as a reducer of Cu2O and a reagent transforming the functional groups from Na+ into the H+ form. The extremely high shrinkage of the porous skeleton containing -COOH groups (in a wet and also dry state) and its limited affinity for water protected the copper from oxidation without the use of special conditions. When macroporous CCE was used as a host material, the composite material (M/H#Cu) contained 18.5 wt% Cu, and copper particles were identified inside the resin beads, but not on their surface where Cu2+ ions appeared during drying. Thermal analysis in an air atmosphere and under N2 showed that dispersing metallic copper within the resin matrix accelerated its decomposition in both media, whereby M/H#Cu decomposed faster than G/H#Cu. It was found that G/H#Cu contained 6.0% bounded water, less than M/H#Cu (7.5%), and that the solid residue after combustion of G/H#Cu and M/H#Cu was CuO (26.28% and 22.80%), while after pyrolysis the solid residue (39.35% and 26.23%) was a mixture of carbon (50%) and metallic copper (50%). The presented composite materials thanks to the antimicrobial, catalytic, reducing, deoxygenating and hydrophobic properties of metallic copper can be used for point-of-use and column water/wastewater treatment systems.

Calcium Deregulation in Neurodegeneration and Neuroinflammation in Parkinson's Disease: Role of Calcium-Storing Organelles and Sodium-Calcium Exchanger.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that lacks effective treatment strategies to halt or delay its progression. The homeostasis of Ca2+ ions is crucial for ensuring optimal cellular functions and survival, especially for neuronal cells. In the context of PD, the systems regulating cellular Ca2+ are compromised, leading to Ca2+-dependent synaptic dysfunction, impaired neuronal plasticity, and ultimately, neuronal loss. Recent research efforts directed toward understanding the pathology of PD have yielded significant insights, particularly highlighting the close relationship between Ca2+ dysregulation, neuroinflammation, and neurodegeneration. However, the precise mechanisms driving the selective loss of dopaminergic neurons in PD remain elusive. The disruption of Ca2+ homeostasis is a key factor, engaging various neurodegenerative and neuroinflammatory pathways and affecting intracellular organelles that store Ca2+. Specifically, impaired functioning of mitochondria, lysosomes, and the endoplasmic reticulum (ER) in Ca2+ metabolism is believed to contribute to the disease's pathophysiology. The Na+-Ca2+ exchanger (NCX) is considered an important key regulator of Ca2+ homeostasis in various cell types, including neurons, astrocytes, and microglia. Alterations in NCX activity are associated with neurodegenerative processes in different models of PD. In this review, we will explore the role of Ca2+ dysregulation and neuroinflammation as primary drivers of PD-related neurodegeneration, with an emphasis on the pivotal role of NCX in the pathology of PD. Consequently, NCXs and their interplay with intracellular organelles may emerge as potentially pivotal players in the mechanisms underlying PD neurodegeneration, providing a promising avenue for therapeutic intervention aimed at halting neurodegeneration.

A new theoretical approach to determine the air outlet temperature of an air-to-ground heat exchanger.

In this study, the control volume method is used to determine the air temperature at the outlet of an air-to-ground heat exchanger. Its implementation consists in dividing the duct of the ground-air heat exchanger into micro-volumes of identical size. An energy balance is then established for each micro-volume. The input parameters used to implement this model are related to the city of Yaoundé in the equatorial zone. The results show that when the total length of the air-to-ground heat exchanger duct varies between 0 and 100 m, the air temperature at the outlet also varies between 34.5 and 24 °C. The air-to-ground heat exchanger operates in cooling mode. As the length of the air-to-ground heat exchanger duct increases, the temperature of the air at the outlet of the air-to-ground heat exchanger decreases, approaching that of the ground. Based on the results obtained using the control volume model, the minimum total length of air-to-ground heat exchanger duct recommended for this zone is 40 m. Admittedly, air pressure drops, air humidity and the geometry of the air-to-ground heat exchanger are aspects that have not yet been taken into account in the implementation of this model. Nevertheless, the control volume method can be used to optimise the parameters influencing the thermal performance of an air-to-ground heat exchanger.•The control volume method is implemented here by dividing the air-to-ground heat exchanger duct into identical micro-volumes and then establishing an energy balance for each micro-volume;•In this work, the control volume method was used to optimise the total length of the duct of a ground air heat exchanger installed in an equatorial zone;•Some important aspects such as air pressure drops, air humidity, and the geometry of the air-to-ground heat exchanger are not yet taken into account in the implementation of the control volume method.

Anion exchanger1 (AE1/SLC4A1) function is impaired in red blood cells from prediabetic subjects: Potential benefits of finger lime (Citrus australasica, Faustrime cultivar) juice extract.

Prediabetes is a risk state that defines a high chance of developing diabetes and cardiovascular disease. Oxidative stress mediated by hyperglycemia-induced production of reactive species could play a crucial role in this context. In the present study, we investigated whether the anion exchange capability mediated by AE1 (SLC4A1), which is sensitive to oxidative stress, was altered in human red blood cells (RBCs) obtained from prediabetic volunteers. In addition, we assessed the precise composition of bioactive compounds and the potential benefits of finger lime juice extract (Citrus australasica, Faustrime cultivar) in counteracting oxidative stress-related functional alterations. Human RBCs from normal and prediabetic volunteers were incubated with 50 µg/mL juice extract for 2 h at 25°C. Juice extract restored alterations of the anion exchange capability mediated by AE1 and prevented the structural rearrangements of AE1 and α/ß-spectrin in prediabetic RBCs. AE1 functional and structural alterations were not associated with an increase in lipid peroxidation or protein oxidation at the level of the plasma membrane. An increased production of intracellular ROS, which provoked the oxidation of hemoglobin to methemoglobin, both reverted by juice extract, was instead observed. Importantly, juice extract also induced a reduction in glycated hemoglobin levels in prediabetic RBCs. Finally, juice extract blunted the overactivation of the endogenous antioxidant enzymes catalase and superoxide dismutase and prevented glutathione depletion in prediabetic RBCs. These findings contribute to clarifying cellular and molecular mechanisms related to oxidative stress and glycation events that may influence RBC and systemic homeostasis in prediabetes, identify AE1 as a sensitive biomarker of RBC structural and function alterations in prediabetes and propose finger lime juice extract as a natural antioxidant for the treatment and/or prevention of the complications associated with the prediabetic condition.

Selective inhibitor of sodium-calcium exchanger, SEA0400, affects NMDA receptor currents and abolishes their calcium-dependent block by tricyclic antidepressants.

The open-channel block of N-methyl-D-aspartate receptors (NMDARs) and their calcium-dependent desensitization (CDD) represent conventional mechanisms of glutamatergic synapse regulation. In neurotrauma, neurodegeneration, and neuropathic pain the clinical benefits of cure with memantine, ketamine, Mg2+, and some tricyclic antidepressants are often attributed to NMDAR open-channel block, while possible involvement of NMDAR CDD in the therapy is not well established. Here the effects of selective high-affinity sodium-calcium exchanger (NCX) isoform 1 inhibitor, SEA0400, on NMDA-activated whole-cell currents and their block by amitriptyline, desipramine and clomipramine recorded by patch-clamp technique in cortical neurons of primary culture were studied. We demonstrated that in the presence of extracellular Ca2+, 50 nM SEA0400 caused a reversible decrease of the steady-state amplitude of NMDAR currents, whereas loading neurons with BAPTA or the removal of extracellular Ca2+ abolished the effect. The decrease did not exceed 30% of the amplitude and did not depend on membrane voltage. The external Mg2+ block and 50 nM SEA0400 inhibition of currents were additive, suggesting their independent modes of action. In the presence of Ca2+ SEA0400 speeded up the decay of NMDAR currents to the steady state determined by CDD. The measured IC50 value of 27 nM for SEA0400-induced inhibition coincides with that for NCX1. Presumably, SEA0400 effects are induced by an enhancement of NMDAR CDD through the inhibition of Ca2+ extrusion by NCX1. SEA0400, in addition, at nanomolar concentrations could interfere with Ca2+-dependent effect of tricyclic antidepressants. In the presence of 50 nM SEA0400, the IC50s for NMDAR inhibition by amitriptyline and desipramine increased by about 20 folds, as the Ca2+-dependent NMDAR inhibition disappeared. This observation highlights NCX1 involvement in amitriptyline and desipramine effects on NMDARs and unmasks competitive relationships between SEA0400 and these antidepressants. Neither amitriptyline nor desipramine could affect NCX3. The open-channel block of NMDARs by these substances was not affected by SEA0400. In agreement, SEA0400 did not change the IC50 for clomipramine, which acts as a pure NMDAR open-channel blocker. Thus, NCX seems to represent a promising molecular target to treat neurological disorders, because of the ability to modulate NMDARs by decreasing the open probability through the enhancement of their CDD.