Search Results (1,170)

The premature senescence of red raspberry leaves severely affects plant growth. In this study, the double-season red raspberry cultivar ‘Polka’ was used, with N₁₅₀ (0.10 g N·kg⁻¹) selected as the treatment group (T150) and N₀ (0 g N·kg⁻¹) set as the control (CK). This study systematically investigated the mechanism of premature senescence in red raspberry leaves under different nitrogen application levels by measuring physiological parameters and conducting a combined multi-omics analysis of transcriptomics and metabolomics. Results showed that T150 plants had 8.34 cm greater height and 1.45 cm greater ground diameter than CK. The chlorophyll, carotenoid, soluble protein, and sugar contents in all leaf parts of T150 were significantly higher than those in CK, whereas soluble starch contents were lower. Malondialdehyde (MDA) content and superoxide anion (O₂⁻) generation rate in the lower leaves of T150 were significantly lower than those in CK. Superoxide sismutase (SOD) and peroxidase (POD) activities in the middle and lower functional leaves of T150 were higher than in CK, while catalase (CAT) activity was lower. Transcriptomic analysis identified 4350 significantly differentially expressed genes, including 2062 upregulated and 2288 downregulated genes. Metabolomic analysis identified 135 differential metabolites, out of which 60 were upregulated and 75 were downregulated. Integrated transcriptomic and metabolomic analysis showed enrichment in the phenylpropanoid biosynthesis (ko00940) and flavonoid biosynthesis (ko00941) pathways, with the former acting as an upstream pathway of the latter. A premature senescence pathway was established, and two key metabolites were identified: chlorogenic acid content decreased, and naringenin chalcone content increased in early senescent leaves, suggesting their pivotal roles in the early senescence of red raspberry leaves. Modulating chlorogenic acid and naringenin chalcone levels could delay premature senescence. Optimizing fertilization strategies may thus reduce senescence risk and enhance the productivity, profitability, and sustainability of the red raspberry industry. Full article

Anion exchange membrane (AEM) water electrolysis is a potentially inexpensive and efficient source of hydrogen production as it uses effective low-cost catalysts. The catalytic activity and performance of nickel iron oxide (NiFeO_x) catalysts for hydrogen production in AEM water electrolyzers were investigated. The NiFeO_x catalysts were synthesized with various iron content weight percentages, and at the stoichiometric ratio for nickel ferrite (NiFe₂O₄). The catalytic activity of NiFeO_x catalyst was evaluated by linear sweep voltammetry (LSV) and chronoamperometry for the oxygen evolution reaction (OER). NiFe₂O₄ showed the highest activity for the OER in a three-electrode system, with 320 mA cm⁻² at 2 V in 1 M KOH solution. NiFe₂O₄ displayed strong stability over a 600 h period at 50 mA cm⁻² in a three-electrode setup, with a degradation rate of 15 μV/h. In single-cell electrolysis using a X-37 T membrane, at 2.2 V in 1 M KOH, the NiFe₂O₄ catalyst had the highest activity of 1100 mA cm⁻² at 45 °C, which increased with the temperature to 1503 mA cm⁻² at 55 °C. The performance of various membranes was examined, and the highest performance of the tested membranes was determined to be that of the Fumatech FAA-3-50 and FAS-50 membranes, implying that membrane performance is strongly correlated with membrane conductivity. The obtained Nyquist plots and equivalent circuit analysis were used to determine cell resistances. It was found that ohmic resistance decreases with an increase in temperature from 45 °C to 55 °C, implying the positive effect of temperature on AEM electrolysis. The FAA-3-50 and FAS-50 membranes were determined to have lower activation and ohmic resistances, indicative of higher conductivity and faster membrane charge transfer. NiFe₂O₄ in an AEM water electrolyzer displayed strong stability, with a voltage degradation rate of 0.833 mV/h over the 12 h durability test. Full article

The demand for anion exchange membranes (AEMs) is growing due to their applications in water electrolysis, CO₂ reduction conversion and fuel cells, as well as water treatment, driven by the increasing energy demand and the need for a sustainable future. However, current AEMs still face challenges, such as insufficient permeability and stability in strongly acidic or alkaline media, which limit their durability and the sustainability of membrane fabrication. In this study, polyvinyl alcohol (PVA) and chitosan (CS) biopolymers are selected for membrane preparation. Zinc oxide (ZnO) and porous organic polymer (POP) nanoparticles are also introduced within the PVA-CS polymer blends to make mixed-matrix membranes (MMMs) with increased OH⁻ transport sites. The membranes are characterized based on typical properties for AEM applications, such as thickness, water uptake, KOH uptake, Cl⁻ and OH⁻ permeability and ion exchange capacity (IEC). The OH⁻ transport of the PVA-CS blend is increased by at least 94.2% compared with commercial membranes. The incorporation of non-porous ZnO and porous POP nanoparticles into the polymer blend does not compromise the OH⁻ transport properties. On the contrary, ZnO nanoparticles enhance the membrane’s water retention capacity, provide basic surface sites that facilitate hydroxide ion conduction and reinforce the mechanical and thermal stability. In parallel, POPs introduce a highly porous architecture that increases the internal surface area and promotes the formation of continuous hydrated pathways, essential to efficient OH⁻ mobility. Furthermore, the presence of POPs also contributes to reinforcing the mechanical integrity of the membrane. Thus, PVA-CS bio-based membranes are a promising alternative to conventional ion exchange membranes for various applications. Full article

This study discloses the noncovalent immobilization of a bienzyme cascade composed of glucose oxidase (GOx) and horseradish peroxidase (HRP) onto magnetically responsive polyamide microparticles (PA MPs). Porous PA6, PA4, and PA12 MPs containing iron fillers were synthesized via activated anionic ring-opening polymerization in suspension, alongside neat PA6 MPs used as a reference. Four hybrid catalytic systems (GOx/HRP@PA) were prepared through sequential adsorption of HRP and GOx onto the various PA MP supports. The initial morphologies of the supports and the hybrid biocatalysts were characterized by SEM, followed by evaluation of the catalytic performance using a two-step glucose oxidation cascade process. Among all systems, the GOx/HRP@PA4-Fe complex exhibited the highest activity, being approximately 1.5 times greater than the native enzyme dyad, followed by the PA6-supported system with slightly inferior performance. All systems obeyed Michaelis–Menten kinetics, with the immobilized cascades displaying higher Kₘ and Vₘₐₓ values than the non-immobilized enzyme pair while maintaining comparable catalytic efficiencies, CE (CE = k_cat/Kₘ). Subsequently, the immobilized and native enzyme systems were employed for the polymerization of aniline. According to UV–VIS, complete monomer conversion was achieved within 24 h for selected catalysts, and FTIR analysis confirmed the formation of polyaniline in the emeraldine base form without the use of template molecules. These findings highlight the potential of Fe-containing polyamide microparticles as efficient supports for the sustainable, enzyme-mediated synthesis of intrinsically conductive aromatic polymers. Full article

This work represents the first use of a phosphonium salt-functionalized β-Cyclodextrin polymer (β-CDP) as a highly selective sensing membrane for monitoring the safety of drinking water against perchlorate ions (ClO₄⁻) using electrochemical impedance spectroscopy (EIS). Structural confirmation via ¹H NMR, ¹³C NMR, ³¹P NMR, and FT-IR spectroscopies combined with AFM and contact angle measurements demonstrate how the enhanced solubility of modified cyclodextrin improves thin film quality. The innovation lies in the synergistic combination of two detection mechanisms: the “Host-Guest” inclusion in the cyclodextrin cavity and anionic exchange between the bromide ions of the phosphonium groups and perchlorate anions. Under optimized functionalization conditions, EIS reveals high sensitivity and selectivity, achieving a record-low detection limit (LOD) of ~10⁻¹² M and a wide linear range of detection (10⁻¹¹ M–10⁻⁴ M). Sensing mechanisms at the functionalized transducer interfaces are examined through numerical fitting of Cole-Cole impedance spectra via a single relaxation equivalent circuit. Real water sample analysis confirms the sensor’s practical applicability, with recoveries between 96.9% and 109.8% and RSDs of 2.4–4.8%. Finally, a comparative study with reported membrane sensors shows that β-CDP offers superior performance, wider range, higher sensitivity, lower LOD, and simpler synthesis. Full article

The Zhurong rover of the Tianwen-1 mission has detected sulfates in its landing area. The analysis of these sulfates provides scientific evidence for exploring past hydration conditions and atmospheric evolution on Mars. As a non-contact technique with long-range detection capability, Laser-Induced Breakdown Spectroscopy (LIBS) is widely used for elemental identification on Mars. However, quantitative analysis of anionic elements using LIBS remains challenging due to the weak characteristic spectral lines of evaporite salt elements, such as sulfur, in LIBS spectra, which provide limited quantitative information. This study proposes a quantitative analysis method for sulfur in sulfate-containing Martian analogs by leveraging spectral line correlations, full-spectrum information, and prior knowledge, aiming to address the challenges of sulfur identification and quantification in Martian exploration. To enhance the accuracy of sulfur quantification, two analytical models for high and low sulfur concentrations were developed. Samples were classified using infrared spectroscopy based on sulfur content levels. Subsequently, multimodal deep learning models were developed for quantitative analysis by integrating LIBS and infrared spectra, based on varying concentrations. Compared to traditional unimodal models, the multimodal method simultaneously utilizes elemental chemical information from LIBS spectra and molecular structural and vibrational characteristics from infrared spectroscopy. Considering that sulfur exhibits distinct absorption bands in infrared spectra but demonstrates weak characteristic lines in LIBS spectra due to its low ionization energy, the combination of both spectral techniques enables the model to capture complementary sample features, thereby effectively improving prediction accuracy and robustness. To validate the advantages of the multimodal approach, comparative analyses were conducted against unimodal methods. Furthermore, to optimize model performance, different feature selection algorithms were evaluated. Ultimately, an XGBoost-based feature selection method incorporating prior knowledge was employed to identify optimal LIBS spectral features, and the selected feature subsets were utilized in multimodal modeling to enhance stability. Experimental results demonstrate that, compared to the BPNN, SVR, and Inception unimodal methods, the proposed multimodal approach achieves at least a 92.36% reduction in RMSE and a 46.3% improvement in R². Full article

Density functional theory calculations were performed to elucidate the mechanistic details and origins of the selectivity of the nickel-catalyzed hydroboration of vinylarenes using B₂pin₂/MeOH. The catalytic cycles involved four sequential elementary steps: hydronickelation, anion exchange, transmetalation, and reductive elimination. Kinetic analyses identified hydronickelation as the rate-determining step with an activation barrier of 19.8 kcal/mol, while transmetalation proceeded through a stepwise mechanism characterized by two distinct transition states. Comprehensive analyses of the relevant transition structures and energetics demonstrated that the observed R-enantioselectivity (94% ee) originated from favorable nonbonding interactions. Lastly, our calculations suggested that the Markovnikov regioselectivity was predominantly governed by steric factors rather than electronic effects. Full article

This study presents a quantitative electrophysiological method to directly measure the passive transport of ammonium ions through bacterial outer membrane porins. Using a zero-current reversal potential assay in planar lipid bilayers under defined bi-ionic gradients, this study evaluates the permeability of ammonium salts through two general diffusion porins: Omp-Pst2 from Providencia stuartii and OmpF from Escherichia coli. Under matched ionic conditions, Omp-Pst2 exhibited significantly higher ammonium flux—approximately 6000 ions per second per monomer at a 1 µM gradient—compared to ~4000 ions per second for OmpF. Importantly, the identity of the accompanying anion (chloride vs. sulfate) modulated both the ion selectivity and flux rate, highlighting the influence of counterion interactions on porin-mediated transport. These findings underscore how structural differences between porins—such as pore geometry and charge distribution—govern ion permeability. The method applied here provides a robust framework for quantifying nutrient flux at the single-channel level and offers novel insights into how Gram-negative bacteria may adapt their membrane transport mechanisms under nitrogen-limited conditions. This work not only enhances our understanding of outer membrane permeability to small ions like ammonium, but also has implications for antimicrobial strategy development and biotechnological applications in nitrogen assimilation. Full article

Soybean (Glycine max L.) is grown worldwide to obtain edible oil, livestock feed, and biodiesel. However, drought and salt stress are becoming serious challenges to global soybean cultivation as they retard the growth of soybean plants and cause significant yield losses. Voltage-dependent anion-selective channel (VDAC) proteins are well-known for their role in drought and salt tolerance in crop plants. In this study, we identified 111 putative VDAC genes randomly distributed in genomes of 14 plant species, including cultivated soybean (Glycine max) and wild soybean (Glycine soja). The comparative phylogenetic studies classified these genes into six different clades and found the highest structural similarities among VDAC genes of G. max and G. soja. From the conserved domain database, porin-3 (PF01459) was found to be the conserved domain in all VDAC proteins. Furthermore, gene annotation studies revealed the role of GmaVDAC proteins in voltage-gated anion channel activity. These proteins were also found to interact with other proteins, especially mitochondrial receptors. A total of 103 miRNAs were predicted to target fifteen GmaVDAC genes. In G. max, these genes were found to be segmentally duplicated and randomly distributed on twelve chromosomes. Transcriptomic analysis revealed that the GmaVDAC18.2 gene showed overexpression in root nodules, whereas the GmaVDAC9.1, GmaVDAC18.1, and GmaVDAC18.2 genes showed overexpression under drought and salt stress conditions. Full article

Copper is essential for various biological functions, but elevated levels in water can pose serious health risks. In this work, we introduce a novel electrochemical sensor designed for the highly sensitive and selective detection of copper ions. The sensor is based on a screen-printed platinum working electrode coated with a solid-state Nafion layer. Compared to previous platinum-based sensors, this design demonstrates enhanced sensitivity, a wide linear detection range (1 µM to 10 mM), and an exceptionally low limit of detection (1 nM). It also offers a rapid response time of 3–6 s, strong selectivity, and excellent stability. Interference from common metal ions such as Cr²⁺, Zn²⁺, Mn²⁺, Pb²⁺, and Fe²⁺ was minimal, with signal deviations remaining below 2%, and performance remained consistent across varying anion concentrations, showing less than 1% deviation. The use of Nafion as a solid-state electrolyte successfully overcomes challenges typically associated with traditional silver-based reference electrodes. These characteristics make the sensor a reliable and practical tool for the rapid, on-site monitoring of water quality. Full article

Rare earth metals (REMs) are vital for high-tech industries, but their extraction from secondary sources is challenging due to environmental and technical constraints. This study investigates the ion-exchange extraction of light REMs (neodymium, praseodymium, and samarium) from sulfuric and phosphoric acid solutions, modeling industrial leachates from apatite concentrates and phosphogypsum. The study considers the use of anion- and cation-exchange resins with different functional groups for efficient and environmentally safe REM separation. Experimental sorption isotherms were obtained under static conditions at 298 K and analyzed using a thermodynamic model based on the linearization of the mass action equation. Equilibrium constants and Gibbs energy were calculated, which reveals the spontaneity of the processes. Cation-exchange resins demonstrated high selectivity towards individual REMs, while anion-exchange resins were suitable for group extraction. Infrared spectral analysis confirmed the presence of sulfate and phosphate complexes in the resin matrix, clarifying the ion-exchange mechanisms. Thermal effect measurements indicated exothermic sorption on anion-exchange resins with negative entropy and endothermic sorption on cation-exchange resins with positive entropy. The findings highlight the potential of ion-exchange resins for selective and sustainable REM recovery, offering a safer alternative to liquid extraction and enabling the valorization of industrial wastes like phosphogypsum for resource recovery. Full article

This study presents a sustainable approach for synthesizing high-performance activated carbon from Spirulina Alga through hydrothermal carbonization followed by chemical activation using potassium hydroxide. The resulting activated carbon exhibited a high Brunauer–Emmett–Teller (BET) surface area of 1747 m²/g and a total pore volume of 1.147 cm³/g, with micropore volume accounting for 0.4 cm³/g. Characterization using Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS), X-ray Photoelectron Spectroscopy (XPS), and gas adsorption analyses confirmed the presence of hierarchical micro- and mesoporosity as well as favorable surface functional groups. The synthesized carbon was used to fabricate electrodes for membrane capacitive deionization (MCDI) along with cation and anion-selective membranes, which were then tested with saline water (500–5000 ppm) and synthetic hard water (898 ppm of total salts). The salt adsorption capacity (SAC) reached 25 (batch) to 40 (continuous) mg/g, while rapid adsorption rates with average salt adsorption rates (ASARs) values exceeding 10 (batch) to 30 (continuous) mg·g⁻¹·min⁻¹ during early stages were obtained. Batch MCDI experiments demonstrated a higher SAC compared to continuous operation, with non-monotonic trends in SAC observed as a function of feed concentration. Ion adsorption kinetics were influenced by ion valency, membrane selectivity, and pore structure. The specific energy consumption (SEC) was calculated as 8–21 kJ/mol for batch and 0.1–0.5 kJ/mol for continuous process. These performance metrics are on par with or surpass those reported in the recent literature for similar single-electrode CDI configurations. The results demonstrate the viability of using Alga-derived carbon as an efficient and eco-friendly electrode material for water desalination technologies. Full article

Background: Under oxidative stress conditions, the increased levels of reactive oxygen species (ROS) within cells disrupt the intracellular homeostasis. Tartary buckwheat peptides exert their effects by scavenging oxidative free radicals, such as superoxide anion and hydrogen peroxide, thereby reducing oxidative damage within cells. Meanwhile, these peptides safeguard mitochondria by maintaining the mitochondrial membrane potential, decreasing the production of mitochondrial oxygen free radicals, and regulating mitochondrial biogenesis and autophagy to preserve mitochondrial homeostasis. Through these mechanisms, Tartary buckwheat peptides restore the intracellular redox balance, sustain cellular energy metabolism and biosynthesis, and ensure normal cellular physiological functions, which is of great significance for cell survival and adaptation under oxidative stress conditions. Objectives: In this experiment, a classical cellular oxidative stress model was established. Indicators related to antioxidant capacity and mitochondrial membrane potential changes, as well as pathways associated with oxidative stress, were selected for detection. The aim was to elucidate the effects of Tartary buckwheat oligopeptides on the metabolism of cells in response to oxidative stress. Methods: In this study, we established an oxidative damage model of mouse skeletal muscle myoblast (SOL8) cells using hydrogen peroxide (H₂O₂), investigated the pre-protective effects of Tartary buckwheat oligopeptides on H₂O₂-induced oxidative stress damage in SOL8 cells at the cellular level, and explored the possible mechanisms. The CCK-8 method is a colorimetric assay based on WST-8-[2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodiumsalt], which is used to detect cell proliferation and cytotoxicity. Results: The value of CCK-8 showed that, when the cells were exposed to 0.01 mmol/L H₂O₂ for 1 h and 10 mg/mL Tartary buckwheat oligopeptides intervention for 48 h, these were the optimal conditions. Compared with the H₂O₂ group, the intervention group (KB/H₂O₂ group) showed that the production of ROS was significantly reduced (p < 0.001), the malondialdehyde (MDA) content was significantly decreased (p < 0.05), and the activity of catalase (CAT) was significantly increased (p < 0.01); the mitochondrial membrane potential in the KB/H₂O₂ group tended to return to the level of the control group, and they all showed dose-dependent effects. Compared with the H₂O₂ group, the mRNA expression of KEAP1 in the KB/H₂O₂ group decreased, while the mRNA expression of NRF2α, HO-1, nrf1, PGC-1, P62, and PINK increased. Conclusions: Therefore, Tartary buckwheat oligopeptides have a significant pre-protective effect on H₂O₂-induced SOL8 cells, possibly by enhancing the activity of superoxide dismutase, reducing ROS attack, balancing mitochondrial membrane potential, and maintaining intracellular homeostasis. Full article

Rationally designing and synthesizing chemosensors capable of simultaneously detecting both anions and cations via water content modulation is challenging. In this study, we synthesized and characterized a novel triazine calixarene derivative-based iodide and copper ion-selective fluorescent “turn-off” sensor. This dual-channeled fluorescent probe is able to recognize Cu²⁺ and I⁻ ions simultaneously in aqueous systems. The fluorescent sensor s4 was synthesized by displacement reaction of acridine with 1, 3-bis (dichloro-mono-triazinoxy) benzene in acetonitrile. Mass spectrometry (MS), UV-vis, and fluorescence spectra were acquired to characterize the fluorescence response of s4 to different cations and anions, while infrared (IR) spectroscopy and isothermal titration calorimetry (ITC) were employed to study the underlying selectivity mechanism of s4 to Cu²⁺ and I⁻. In detail, s4 displayed extremely high sensitivity to Cu²⁺ with over 80% fluorescence decrement caused by the paramagnetic nature of Cu²⁺ in the aqueous media. The reversible fluorescence response to Cu²⁺ and the responses to Cu²⁺ in the solution of other potential interferent cations, such as Li⁺, Na⁺, K⁺, Ca²⁺, Cd²⁺, Zn²⁺, Sr²⁺, Ni²⁺, Co²⁺ were also investigated. Probe s4 also exhibited very good fluorescence selectivity to iodide ions under various anion (F⁻, Cl⁻, Br⁻, NO₃⁻, HSO₄⁻, ClO₄⁻, PF₆⁻, AcO⁻, H₂PO₄⁻) interferences. In addition to the fluorescent response to I⁻, s4 showed a highly selective naked-eye-detectable color change from colorless to yellow with the other tested anions. Full article

Organic anion transporting polypeptide 1B1 (OATP1B1) is selectively expressed at the basolateral membrane of human hepatocytes and plays a crucial role in the absorption of various xenobiotic compounds, including many important clinical drugs. Oligomerization with regulatory proteins is a common mechanism for regulating membrane protein functions. In the present study, we found that knocking down the scaffold protein radixin, which is the major member of the ERM family expressed in the liver, significantly enhanced the uptake function of OATP1B1. On the other hand, the overexpression of the phospho-mimic form of radixin (radixin-D) reduced the uptake function and cell surface level of OATP1B1, while the wild-type and phospho-dormant form of radixin (radixin-A) did not exhibit the same effect. Further investigation revealed that radixin interacts with OATP1B1. Activation of protein kinase C (PKC), which our previous study showed accelerates the internalization of OATP1B1, was found to increase the phosphorylation level of radixin associated with OATP1B1. The knockdown of radixin significantly diminished the suppressive effect of PKC on the function and cell surface levels of OATP1B1. These results suggested that OATP1B1 forms complexes with radixin, which may be phosphorylated by PKC, leading to reduced cell surface expression and activity of the transporter. Full article