Search Results (5,762)

With the in-depth advancement of the “dual carbon” strategy, Proton Exchange Membrane Fuel Cells (PEMFCs), as efficient and clean energy conversion devices, show great potential in the fields of transportation power and stationary power generation. For multi-stack fuel cell systems, a hierarchical optimization strategy based on Pareto decoupling and real-time correction is presented to achieve system efficiency improvement and balanced management of stack aging. Firstly, the Forgetting Factor Recursive Least Square (FFRLS) method is adopted to online identify the parameters of the system’s net output power-efficiency curve. Furthermore, in the steady-state layer, the Arithmetic Optimization Algorithm (AOA) is used to construct an efficiency-optimal candidate solution set. The Dijkstra algorithm is combined to search for the optimal power gradient path, generating a reference power table. In the dynamic layer, with the reference power table as the basis, the AOA algorithm is used to take efficiency optimization as the goal. Load fluctuations are suppressed in real time through strong constraints, realizing the balance between dynamic efficiency and operational stability. This method ensures the stable operation of the system and significantly improves the overall economy and adaptability of power allocation. Simulation results show that this strategy can effectively improve the overall operating efficiency of the system, slow down the stack aging rate, and ensure the stable operation of the system. Full article

This study investigates the durability of silicone-based membranes in contact with hempcrete under combined moisture and temperature exposure. Membrane specimens were aged in contact with non-treated and treated hempcrete under dry and wet conditions at temperatures up to 90 °C. The evolution of chemical, thermal, and microstructural properties was characterized using FTIR, TGA, DSC, optical microscopy, and SEM–EDS analyses. Results show that dry exposure does not induce measurable changes in membrane structure or performance, confirming that temperature alone is not a critical degradation factor. In contrast, wet exposure leads to significant chemical, thermal, and microstructural changes in the membrane, including degradation of the siloxane network, reduced polymer chain mobility, and the formation of calcium-rich mineral deposits at the interface. These results indicate that membrane degradation is governed by a coupled moisture–ion mechanism involving ion transport, mineral deposition, and hydrolysis of the polymer network. Fiber treatment slightly reduces the aggressiveness of the leachate but does not prevent degradation under wet conditions. Overall, moisture availability and leachate chemistry are identified as key factors controlling the durability of silicone membranes in contact with bio-based materials. Full article

Polymeric membranes are widely investigated for CO₂ separation; however, their performance is often limited by the permeability–selectivity trade-off. Incorporating metal–organic frameworks (MOFs) and designing composite membrane architectures are promising strategies to overcome these limitations. This study aims to evaluate the effect of incorporating MOF-74 (Cu and Ni variants) into a polydimethylsiloxane (PDMS) selective layer supported on a polysulfone (PSF) membrane for enhanced CO₂/N₂ separation performance. Dual-layer PDMS/PSF composite membranes were fabricated via phase inversion for the PSF support, followed by solution casting of the PDMS/MOF layer. The developed membrane architecture introduces a synergistic design that combines the mechanical robustness of PSF with the selective transport capability of PDMS and the strong CO₂ affinity of MOF-74, offering an effective strategy for improving gas separation efficiency. Gas permeation performance was assessed using single-gas CO₂ and N₂ measurements at feed pressures of 2–5 bar. The incorporation of MOF-74 improved CO₂ transport properties, with the 1 wt.% Cu-MOF-74 composite membrane achieving a CO₂ permeance of 912.5 GPU and a CO₂/N₂ ideal selectivity of 94.75. The dual-layer configuration significantly enhanced permeance compared with unsupported mixed-matrix membranes while maintaining selectivity. Additionally, the composite membranes exhibited improved mechanical strength due to the PSF support layer. The findings demonstrate that dual-layer PDMS/PSF composite membranes incorporating MOF-74 provide a promising proof-of-concept approach for improving CO₂ separation performance. Further studies involving mixed-gas testing and long-term stability are required to assess their practical applicability. Full article

Chronic kidney disease (CKD) is characterized by the progressive accumulation of uremic toxins (UTs), which contribute to systemic complications, increased cardiovascular risk, and disease progression. Epidemiological and experimental evidence demonstrate pronounced sex differences in CKD progression and outcomes, yet the mechanisms underlying sex-specific uremic toxicity remain unclear. This review synthesizes current knowledge on sex differences in the origin, metabolism, transport, and biological effects of UTs, with a focus on sex-dependent regulatory mechanisms along the gut–liver–kidney axis. Sex hormones influence key determinants of toxin handling, including gut microbiota composition, hepatic enzyme activity, plasma protein binding, membrane transporter expression, and intracellular signaling pathways. Together, these factors regulate systemic toxin exposure and tissue susceptibility to injury. CKD also disrupts endocrine homeostasis, creating bidirectional interactions between hormonal regulation and toxin accumulation. Experimental and limited clinical evidence suggest that sex may influence circulating toxin profiles and susceptibility to toxin-associated complications. Collectively, sex is an important modulator of uremic toxicity, with sex hormones mediating at least part of the sex differences. A sex-informed framework may improve fundamental understanding through mechanistic studies and future clinical research may help clarify its relevance for biomarker development and support the development of personalized therapeutic strategies for CKD. Full article

This study reports the intermediate-temperature proton exchange membrane (IT-PEM) based on an oligomeric vinyl sulfonic acid (OVS)-infiltrated crosslinked porous polybenzimidazole (cp-PBI) framework. The cp-PBI membrane, fabricated via ZIF-8-templated porosity and covalent crosslinking, provides a mechanically robust and chemically stable host matrix that enables high uptake and uniform distribution of OVS throughout the membrane bulk. In situ oligomerization of vinyl sulfonic acid yields a wax-like OVS ionomer with high proton density and reduced mobility, effectively suppressing ionomer leaching while maintaining efficient proton transport under anhydrous conditions. The resulting membrane exhibits high proton conductivity of 8.4 × 10⁻³ S cm⁻¹ at room temperature and 2.6 × 10⁻² S cm⁻¹ at 110 °C without any external humidification. Compared to dense PBI and conventional phosphoric acid (PA)-doped systems, the composite membrane demonstrates significantly enhanced ionomer retention, with only 2.3 wt% loss under compressive conditions and improved stability under humid environments. These results highlight the synergistic effect of a porous crosslinked host and viscous oligomeric ionomer, providing a promising strategy for designing stable, high-performance IT-PEMs. Full article

Background: Currently, increasing attention is being paid to the role of genes other than CFTR and their variants as factors modifying the course of cystic fibrosis (CF). One such gene is SLC26A9, which encodes a protein involved in chloride and bicarbonate transport across the epithelial cell membrane. Variants of SLC26A9, such as c.229G>A (p.Gly77Ser) and c.1885C>T (p.Pro629Ser), have been described in patients with severe and rapidly progressive CF. The aim of this study was to identify SLC26A9 variants in a group of 20 patients with CF. Methods: DNA was isolated from blood samples and collected from all patients. Fragments of exons 3 and 17 of the SLC26A9 gene were amplified by PCR and sequenced using the Sanger method. Results: An SLC26A9 variant was identified in two siblings. These patients were diagnosed with CF in adulthood and presented with moderate pulmonary symptoms without exocrine pancreatic insufficiency. In both siblings carrying the CFTR variants p.Phe508del and c.3140-26A>G, the SLC26A9 variant c.1847C>T (p.Pro616Leu) was detected. This variant has not been widely described in the literature and has not previously been associated with CF. Conclusions: The c.1847C>T (p.Pro616Leu) variant is located near a domain that may affect the transport function of the SLC26A9 protein. However, patients in whom the variant was identified did not present a severe disease phenotype. Further studies on larger patient cohorts are required, and at present this variant should be considered of uncertain significance in CF. Full article

Blue honeysuckle is an emerging small berry with high nutritional value; However, the soft texture of its fresh fruit leads to poor storability and transportability, severely limiting its economic returns. Calcium is a key element in maintaining the structural integrity of plant cell walls and membranes, and plays a decisive role in fruit firmness and postharvest quality. To elucidate the effects of different calcium fertilizers on the fruit firmness, yield, and fruit quality of blue honeysuckle, a two-year field experiment was conducted using foliar application of 2 L of calcium fertilizer (CaC, CaA, CaL, SAC and AAC) at a concentration of 1 mg/L, with the control receiving an equal volume of water. The results showed that sugar alcohol calcium had the best effect on fruit firmness, fresh weight, yield, solid-acid ratio, total anthocyanins, and ascorbic acid, significantly improving yield and quality. Amino acid calcium was most effective in increasing fruit volume and fruit number per plant. Calcium acetate and calcium lactate showed balanced improvements across indicators. Calcium chloride significantly enhanced fruit shape index, total phenols, and total flavonoids. These findings elucidate the specific effects of various treatments on key fruit traits, providing a theoretical basis for precision cultivation and quality regulation, thereby facilitating the standardization and high-quality development of the industry. Full article

ATP-binding cassette (ABC) transporters are one of the largest superfamilies of membrane proteins, but little is known about the structural and evolutionary features of their non-domain regions. To clarify the diversity of these non-canonical regions across evolutionary lineages, we performed an analysis of intrinsically disordered regions, site-specific selection and predicted post-translational modification (PTM) sites among five architectural classes involving 1581 prokaryotic and eukaryotic sequences. Linker and flanking regions were more disordered than transmembrane and nucleotide-binding domains in all architectures. Disorder fraction was significantly different between region types after phylogenetic correction (Pagel’s λ ≈ 0.97). Predicted PTM sites are enriched in disordered non-domain segments, with N-linked glycosylation and phosphoserine showing the strongest positive enrichment. A total of 140 sites satisfied a tiered conservation criterion (MusiteDeep score ≥ 0.5; cross-species conservancy ≥ 30%), including 40 high-confidence or moderate-confidence sites (conservancy ≥ 50%) as well as novel phosphotyrosine candidates in half transporters and NBD-only proteins. Site-specific selection analyses showed pervasive purifying selection across domain cores and architecture-dependent enrichment of episodic positive selection in non-domain regions, with significant non-domain enrichment in full reverse and half forward transporters (Fisher’s exact, BH-adjusted p < 0.05). In summary, these findings establish that non-canonical regions of ABC transporters are evolutionarily dynamic and contain conserved predicted modification sites, supporting the idea that these regions are evolutionary dynamic segments that deserve experimental characterization as candidate regulatory interfaces. Full article

This study aimed to investigate the regulatory effect and cryoprotective mechanism of melatonin (MT) on the physiological functions of Lactobacillus plantarum FQR during freezing and freeze-drying. Results indicated that the addition of 5 mg/mL MT as a cryoprotectant maximized the freeze-drying survival rate to 32.04 ± 2.14%. MT effectively alleviated low-temperature and freeze-drying stress by reducing extracellular alkaline phosphatase activity, enhancing intracellular lactate dehydrogenase activity, and decreasing extracellular β-galactosidase activity without significant differences. Higher survival rates in defining medium further suggested that MT reduced damage to cell wall and membrane structures during lyophilisation, decreased membrane permeability, and preserved cellular physiological functions. In addition, MT supported cellular energy metabolism and protein synthesis, enhanced transmembrane potential to facilitate ATP transport, and helped maintain intracellular and extracellular pH balance. The prepared freeze-drying protectant containing 69.80 mg/mL exopolysaccharides (EPS) and 4.25 mg/mL MT showed better protective effects than the control group. MT also increased bound water content, lowered the freezing point of the solution, and inhibited ice crystal formation. Transcriptomic analysis revealed that amino acid biosynthesis, amino acid metabolism, and ABC transport systems were the primary pathways affected by MT treatment. These findings demonstrate that MT improves freeze-drying tolerance by maintaining membrane integrity, regulating cellular metabolism, and enhancing oxidative stress resistance. Given its natural biosynthetic origin, generally recognized as safe (GRAS) status, and absence of residual solvents or allergenic proteins, MT can be safely considered for incorporation into food and nutraceutical products. This study underscores the practical relevance of MT as a functional component in compound cryoprotectants, providing a feasible strategy to enhance the viability, stability, and industrial applicability of Lactobacillus plantarum during freeze-drying and storage. Full article

To address performance limitations in proton exchange membrane fuel cells (PEMFCs), this work proposes and numerically investigates a cathode gas diffusion layer (GDL) with conical frustum grooves. A systematic comparison is performed across three GDL configurations: a baseline structure without grooves, a design with cylindrical grooves, and the proposed conical frustum grooves. The results demonstrate that the conical frustum grooves effectively enhance liquid water removal, oxygen mass transport, membrane current density, and peak power density. This improvement arises as the grooves expand transport pathways for both liquid water and oxygen, facilitating more robust electrochemical reactions. A parametric analysis is further conducted to evaluate the effects of groove spacing, depth, top radius, and bottom radius. Reduced groove spacing, together with increased groove depth, top radius, and bottom radius, consistently improves water management and oxygen delivery. However, membrane current density and power density do not vary monotonically with groove depth and bottom radius. The optimal values for these two parameters are identified as 0.3 mm and 0.5 mm, respectively. Full article

Sialic acids are a diverse class of widely distributed monosaccharides that are engaged in a wide range of biological processes. Sialin, a sialic acid/proton symporter, transports sialic acid across membranes between the lysosomal lumen and cytosol, playing a critical role in sialin metabolism. Taking advantage of recently published experimental structures of sialin, we report here the first computational study that probes the molecular mechanism of ligand transport through sialin, which is yet to be fully understood. In particular, we carry out steered molecular dynamics simulations of the transport of N-acetylneuraminic acid, the most widely spread natural derivative of sialic acids, through sialin with two key glutamate residues (E171 and E175) in various protonation states. The previously proposed model is refined with enriched atomistic details from this study for the cotransport of sialic acid and proton. With additional quantum calculations, our data suggest a possible explanation for why mutation R168A retains most of the transport activities, but R168K does not. Full article

Heavy metals in the soil inhibit plant growth, which significantly reduce the crop yield and quality. Natural Resistance-Associated Macrophage Proteins (NRAMP) are widely distributed on the plasma and vacuolar membranes of plant roots, stems, and leaves. The NRAMP gene family plays a crucial role in modulating plant heavy-metal uptake, sequestration, distribution, and translocation, while the molecular evolution and mechanisms underlying these processes remain unclear. Here, we reviewed recent progress on plant NRAMP genes, focusing on their structural characteristics and functions in the absorption, transport, accumulation, and detoxification of various heavy metals. Furthermore, we performed an evolutionary analysis of NRAMP in green plants, indicating expansion and tandem duplication in ferns. In addition, their key amino acid sequences and secondary structures were highly conserved across plant species. The expression of diverse tissue showed that NRAMP genes displayed distinct spatial regulation in the leaves and roots. We also explored the underlying molecular mechanisms and regulatory pathways by which NRAMP genes influence heavy metal uptake. Therefore, by integrating structural conservation, molecular evolution, tissue- and single-cell expression patterns, ion-stress-responsive expression, regulatory pathways, and the Cd–Mn nutrient–toxin trade-off, this review provides a framework for identifying unresolved NRAMP functions and for guiding future strategies in low-heavy-metal crop breeding, metal homeostasis engineering, and phytoremediation. Full article

China is the world’s largest producer of hydrogen, and it has the potential to export renewable hydrogen and its derivatives. Japan has set ambitious targets for developing a hydrogen-based society but is facing cost challenges. There is strong potential for China and Japan to cooperate regarding renewable hydrogen across the value chain. This study evaluates the cooperation opportunities from the 3E perspective (energy security, economics, and the environment). It estimates the renewable hydrogen production potential in both countries, as well as the economics and greenhouse gas (GHG) emissions associated with the production and export of renewable hydrogen from China to Japan using proton exchange membrane (PEM) technology. The renewable hydrogen production potential in China is estimated to be 12.00 Mt/year by 2035 in the base case of this study, providing a strong foundation for exports to Japan. The levelized cost of hydrogen (LCOH) using PEM technology and onshore wind is estimated at 4.27 USD/kg H₂ in China and 11.01 USD/kg H₂ in Japan for projects built in 2025. Even after accounting for liquefaction costs in China, transport costs from China to Japan (Chifeng—Dalian—Kobe) and regasification costs in Japan, renewable hydrogen produced in China remains more cost-effective than that produced in Japan. In terms of GHG emissions, when renewable hydrogen is produced using wind power, and wind power is also used for liquefaction and other electricity-consuming processes, the total emissions within the case study boundary amount to 2.24 kg CO₂-eq/kg H₂, below Japan’s low-carbon hydrogen threshold of 3.4 CO₂-eq/kg H₂. This study also discusses the challenges which are critical to facilitating cooperation, particularly in regards to coordinating standards and certification systems between the two countries. Full article

A multilayer gradient composite membrane was fabricated on a PES ultrafiltration substrate through layer-by-layer assembly of chitosan (CS) and montmorillonite (MMT), followed by Ca²⁺ crosslinking. The designed architecture forms a multi-layer gradient composite membrane through successive self-assembly, aiming to balance adsorption, interfacial transport and structural stability. SEM observations showed a clear stratified configuration with relatively uniform thickness distribution, including a relatively dense MMT-rich surface layer and a porous PES support that preserved mass-transfer channels. FTIR confirmed the introduction of hydroxyl/amino-containing CS and aluminosilicate-related MMT species onto the membrane surface, indicating successful incorporation of both organic and inorganic components. TG–DTG results further suggested enhanced thermal stability arising from the cooperative effect of the inorganic lamellae and the polymer framework. In dynamic tests, the membrane displayed concentration-responsive adsorption behavior toward gatifloxacin, ciprofloxacin and ofloxacin, and different pollutants reached equilibrium or quasi-steady states at different rates. Comparative kinetic results at the same initial concentration showed that diclofenac, gatifloxacin and ciprofloxacin approached stable plateaus much faster, whereas ofloxacin increased slowly and did not reach an obvious plateau within the tested period. These results indicate that pollutant removal was jointly governed by interfacial interactions, gradient-layer diffusion resistance and overall transport behavior rather than by concentration alone. Overall, the layer-by-layer strategy provided a controllable route for constructing gradient functional layers on PES membranes, demonstrating potential for advanced treatment of antibiotic-containing wastewater and related pharmaceutical effluents. Full article

Serotonin (5-HT) signaling is strictly controlled by the serotonin transporter (SERT). The present study aims to establish optogenetic approaches for the control of SERT localization and function by modulating the interaction between SERT and its regulatory protein, soluble guanylate cyclase (sGC). We generated several cell lines that stably express blue light-inducible optogenetic elements fused to sGC or the fourth internal loop (IL4) motif of SERT. Our results indicated that blue light-induced SERT-sGC interaction by heterodimerizing SsrA embedded in the membrane-associated improved light-induced dimer (iLID) and SspB-sGCβ1 decreased SERT localization in the plasma membrane, thus reducing the maximum transport velocity of SERT without affecting its K_m for substrate. The light-induced subcellular redistribution of SERT was shown to be attributable to an interference of the SERT-sGC interaction with SERT trafficking but not PKC-mediated internalization. In addition, the light-induced SERT-sGC interaction was blocked by the IL4 peptide or a mutation in the IL4 motif. Furthermore, light-induced exposure of the IL4 motif in iLID decreased the SERT-sGC interaction by displacing SERT from the SERT-sGC complex, thus increasing SERT localization in the membrane and elevating its ability for substrate uptake. This study achieved light-inducible modulation of the protein–protein interaction that allows for the study of biochemical and cellular processes in live cells. Full article