Search Results (791)

Plant-derived nanocellulose particles, such as cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs), are becoming increasingly popular for a wide range of applications. In particular, when they are employed as rheology modifiers and/or fillers, a choice between CNFs and CNCs is often not obvious. Here, we present the results of a comparative study on the rheological properties of suspensions and gels of carboxymethylated CNFs and CNCs with the same surface chemistry, surface density of charged groups, and thickness. We demonstrate that, at the same weight concentration, CNF suspensions have much higher viscosity and storage modulus, which is due to their longer length providing many entanglements. However, when comparing at the same nanoparticle concentration relative to C*, the situation is reversed: viscosity and storage modulus of CNCs appear to be much higher. This may be due in particular to the higher rigidity and intrinsic strength of highly crystalline CNCs. The gel points for CNF and CNC suspensions (without crosslinker) were compared for the first time. It was found that in the case of CNFs, the gel point occurs at a 3.5-fold lower concentration compared to that of CNCs. Hydrogels were also obtained by crosslinking negatively charged nanocellulose particles of both types by divalent calcium cations. For the first time, the thermodynamic parameters of the crosslinking of carboxymethylated CNFs by calcium ions were determined. Isothermal titration calorimetry data revealed that, for both CNFs and CNCs, crosslinking is endothermic and driven by increasing entropy, which is most likely due to the release of water molecules surrounding the interacting nanoparticles and Ca²⁺ ions. The addition of CaCl₂ to suspensions of nanocellulose particles leads to an increase in the storage modulus; the increase being much more significant for CNCs. Physically crosslinked hydrogels of both CNFs and CNCs can be reversibly destroyed by increasing the shear rate and then quickly recover up to 85% of their original viscosity when the shear rate decreases. The recovery time for CFC networks is only 6 s, which is much shorter than that of CNC networks. This property is promising for various applications, where nanocellulose suspensions are subjected to high shear forces (e.g., mixing, stirring, extrusion, injection, coating) and then need to regain their original properties when at rest. Full article

Understanding groundwater quality and its controlling mechanisms is vital for the sustainable use of water resources in agriculturally intensive regions. This study evaluates the hydrochemical characteristics, controlling geochemical processes, and overall water quality of 226 groundwater samples collected from a typical agricultural reclamation area in the Sanjiang Plain, northeastern China. Major ion compositions indicate that groundwater is predominantly of the Ca–HCO₃ type, with bicarbonate, calcium, and magnesium as the dominant constituents. Spatial and statistical analyses reveal that rock weathering—particularly the dissolution of carbonates and silicates—is the primary natural process influencing groundwater chemistry, while cation exchange contributes moderately. Anthropogenic inputs, especially from fertilizers, livestock waste, and wastewater discharge, were found to elevate concentrations of NO₃⁻, Cl⁻, and SO₄²⁻ in localized zones. The entropy-weighted water quality index (EWQI) was applied to assess overall groundwater suitability. Results show that 89.8% of samples fall into “excellent” or “good” categories, though 6.6% of samples indicate poor to very poor water quality. This study identified the hydrochemical characteristics, sources of substances, and water quality of groundwater in the reclamation area, providing a basis for scientific prevention and control, rational utilization, and protection of groundwater resources. Full article

Soil salinity poses a critical threat to global agricultural productivity, exacerbating food security challenges in arid and semi-arid regions. This review synthesizes current knowledge on the physiological and biochemical impacts of salinity stress in plants, with a focus on the role of gibberellic acid (GA₃) in mitigating these effects. Salinity disrupts ion homeostasis, induces osmotic stress, and generates reactive oxygen species (ROS), leading to reduced chlorophyll content, impaired photosynthesis, and stunted growth across all developmental stages, i.e., from seed germination to flowering. Excess sodium (Na⁺) and chloride (Cl⁻) accumulation disrupts nutrient uptake, destabilizes membranes, and inhibits enzymes critical for carbon fixation, such as Rubisco. GA₃ emerges as a key regulator of salinity resilience, enhancing stress tolerance through various mechanisms like scavenging ROS, stabilizing photosynthetic machinery, modulating stomatal conductance, and promoting osmotic adjustment via osmolyte accumulation (e.g., proline). Plant hormone’s interaction with DELLA proteins and cross-talk with abscisic acid, ethylene, and calcium signaling pathways further fine-tune stress responses. However, gaps persist in understanding GA₃-mediated floral induction under salinity and its precise role in restoring photosynthetic efficiency. While exogenous GA₃ application improves growth parameters, its efficacy depends on the concentration- and species-dependent, with lower doses often proving beneficial and optimum doses potentially inhibitory. Field validation of lab-based findings is critical, given variations in soil chemistry and irrigation practices. Future research must integrate biotechnological tools (CRISPR, transcriptomics) to unravel GA₃ signaling networks, optimize delivery methods, and develop climate-resilient crops. This review underscores the urgency of interdisciplinary approaches to harness GA₃’s potential in sustainable salinity management, ensuring food security and safety in the rapidly salinizing world. Full article

Background/Objectives: Childhood is marked by frequent musculoskeletal injuries, with fractures representing a major cause of pediatric trauma admissions. Unstable long-bone fractures often require surgical stabilization, commonly achieved using elastic stable intramedullary nailing (ESIN). Although this method ensures effective fixation and early mobilization, concerns remain regarding potential metal ion release in growing children. This study aimed to assess changes in calcium, magnesium, copper, zinc, titanium, and aluminum concentrations in blood and material from the medullary cavity of forearm fractures following intramedullary fixation. Methods: A prospective study was conducted on 40 patients aged 4–15 years treated with ESIN at the University Children’s Hospital in Lublin. Peripheral blood and material from the medullary cavity were collected before implantation and at implant removal. Elemental concentrations were determined using high-resolution ICP-OES, and statistical analyses included paired comparisons, delta values, and multivariate methods. Results: No significant systemic changes were found for calcium, magnesium, copper, zinc, or aluminum. A modest but significant increase in blood titanium levels was observed after treatment (p = 0.0075), especially in patients with two rods. Multivariate analysis confirmed overall stability of elemental profiles, with titanium contributing most strongly to post-treatment variation. Conclusions: Intramedullary titanium fixation in children does not significantly disrupt systemic mineral homeostasis. The slight increase in circulating titanium reflects implant exposure rather than toxicity, supporting the safety of ESIN, although continued monitoring of metallic elements may be warranted. Full article

The poly-lactic acid (PLA) coating was widely applied to the WE43 alloy to modulate its degradation for biomedical implants, a strategy whose long-term efficacy is critically dictated by the coating’s protective and ion-permeation properties under dynamic physiological flow. This work systematically investigates the corrosion performance under the such flow condition using a novel in situ monitoring method. This method enables a direct, in situ assessment of both the ion-permeation rate across the PLA membrane acted as the coating and the concurrent evolution of the electrochemical properties of the membrane as well as the WE43 alloy substrate. Results revealed that the applied flow accelerated the formation of micro-cracks in the PLA membrane, which facilitated the permeation of Na⁺ and Cl⁻ ions and thereby intensified the corrosion of the underlying substrate. During the initial 15 days, the ion permeation rates for Na⁺ and Cl⁻ ions under the flow condition were 0.097 and 0.042 mmol/(L·h), respectively. The degradation rate of the substrate exhibited a strong positive correlation with the concentration of permeated Cl⁻ ions. In contrast, the deposition of calcium-containing compounds was identified as a time-dependent process, governed by the permeation kinetics of Ca²⁺ ions through the membrane. Full article

Hydrometallurgy is currently the mainstream industrial process for recovering valuable components (nickel, cobalt, manganese, lithium, etc.) from spent ternary lithium-ion battery cathode materials. During the crushing of lithium batteries, cathode materials, anode materials (graphite), and electrolytes become mixed. Consequently, fluoride ions inevitably enter the leaching solution during the hydrometallurgical recycling process, with concentrations as high as 100–300 mg/L. These fluoride ions not only adversely affect the quality of the recovered precursor products but also pose environmental risks. To address this issue, this study employs a synthesized lanthanum–zirconium (La@Zr) composite material, with a specific surface area of 67.41 m²/g and a pore size of 2–50 nm, which can reduce the fluoride ion concentration in the leaching solution to below 5 mg/L, significantly lower than the 20 mg/L or higher that is typically achieved with traditional calcium salt defluorination processes, without introducing new impurities. Under optimal adsorption conditions, the lanthanum–zirconium adsorbent exhibits a fluoride ion adsorption capacity of 193.4 mg/g in the leaching solution, surpassing that of many existing metal-based adsorbents. At the same time as the valuable metals, Li, Ni, and Co, are basically not adsorbed, the selective adsorption of fluoride ions can be achieved. Adsorption isotherm studies indicate that the adsorption process follows the Langmuir model, suggesting monolayer adsorption. The secondary adsorption process is primarily governed by chemical adsorption, and elevated temperatures facilitate the removal of fluoride ions. Kinetic studies demonstrate that the adsorption process is well described by the pseudo-second-order model. After desorption and regeneration with NaOH solution, the adsorbent still has a favorable fluoride removal performance, and the adsorption rate of fluoride ions can still reach 95% after four cycles of use. With its high capacity, rapid kinetics, and excellent selectivity, the adsorbent is highly promising for large-scale implementation. Full article

This study explored the chloride binding characteristics and mechanisms of sulphoaluminate cement (SAC) by isolating its principal mineral component, anhydrous calcium sulphoaluminate (${\mathrm{C}}_4{\mathrm{A}}_3\stackrel{\mathrm{-}}{\mathrm{S}}$), as the research object. Chloride ingress was investigated under external penetration and internal incorporation conditions, with gypsum dosage varied at molar ratios of 1:0, 1:1, and 1:2 relative to ${ \mathrm{C}}_4{\mathrm{A}}_3\stackrel{\mathrm{-}}{\mathrm{S}}$. Through chloride binding experiments and hydration product analysis performed by XRD and TG, the following findings were obtained: under external chloride exposure, the binding capacity increased with rising solution concentration and immersion time. External chloride binding was attributed to SO₄²⁻/Cl⁻ ion exchange in AFm to generate Friedel’s salt and was complemented by physical adsorption of chloride in AH₃ gel. Under internal chloride incorporation, binding capacity increased progressively with curing age. Internal chloride binding involved the direct participation of Cl⁻ in hydration reactions to form Friedel’s salt in addition to the chemical reaction of AFm and the physical adsorption of AH₃. Gypsum dosage critically regulates the AFm/AFt ratio, which in turn governs chloride binding efficiency under both external and internal chloride scenarios (e.g., after immersion in 1 mol/L NaCl solution, the bound chloride content for ${\mathrm{C}}_4{\mathrm{A}}_3\stackrel{\mathrm{-}}{\mathrm{S}}$/gypsum ratios of 1:0, 1:1, and 1:2 was 50.94, 27.28, and 13.47 mg/g, respectively). Full article

Calcium (Ca²⁺ ions) is one of the dominant elements that contribute to water hardness, scaling in pipes, bathroom faucets, and kitchen utensils. Herein, we report on the development of poly(vinylidene fluoride-co-hexafluoropropylene) cellulose acetate (PVDF-HFP/CA) films for the treatment of Ca²⁺ ions as one of the constituents that causes water hardness. CA and PVDF-HFP polymers, and their blend consisting of 3 wt.% PVDF-HFP/CA, were effectively synthesised through the phase inversion technique. Analysis using thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) confirmed the effective incorporation of 3 wt.% PVDF-HFP into the cellulose acetate film. Parameters such as temperature, initial concentration, pH, adsorbent dosage and contact time were investigated in batch studies during the removal of Ca²⁺ ions in synthetic water samples. Under optimal conditions (pH 7, adsorbent dosage of 0.5 mg/L, and concentration of 120 mg/L), the 3 wt.% PVDF-HFP/CA film achieved a 99% adsorption efficiency for Ca²⁺ ions in 90 min. The adsorption process adhered to pseudo-second-order and Freundlich isotherm models, which suggest that the adsorption of Ca²⁺ ions is heterogeneous. The maximum adsorption efficiency achieved was 56 mg/g, indicating an endothermic physisorption process. The 3 wt.% PVDF-HFP/CA film maintained higher adsorption in the presence of counter ions and in a binary system, and it could be recycled at least three times. Thus, the findings demonstrated that the 3 wt.% PVDF-HFP/CA film could be a valuable material for Ca²⁺ ions removal to acceptable drinking water levels. Full article

Microsomal fractions from yeast Δale1 cells harbouring the empty plasmid pYES2/CT and from yeast cells overexpressing PtATS2a (Phatr3_J11916) or PtATS2b (Phatr3_J43099) were used in the studies. When sn-1-18:1-LPA and [¹⁴C]16:0-CoA were used as exogenous substrates, both PtATS2a and PtATS2b showed the highest activity at 23 °C in the range of temperatures tested from 10 to 60 °C. Both enzymes showed the highest activity in alkaline pH. For PtATS2a, it was pH 10 while for PtATS2b, it was pH 11. At pH 6 and pH 12, the activities of both enzymes were very low. The calcium ions at concentrations of 0.05–1 mM drastically decreased the activity of both enzymes. The magnesium ions at a concentration of 0.05 mM had a little effect on the activity of both enzymes, while higher concentrations (0.5 mM and 1 mM) significantly inhibited their activity. To study the substrate specificity, seventeen different acyl-CoAs in combinations with sn-1-[¹⁴C]18:1-LPA were used. PtATS2a showed the highest preference for 18:4-CoA n-3 while PtATS2b for 18:1-CoA. The pattern of utilisation of other acyl-CoAs tested also differed between the two enzymes. The presented studies, for the first time, characterised LPAAT type enzymes from diatoms, organisms that naturally produced very-long-chain polyunsaturated fatty acids (VLC-PUFA). Full article

Concrete structures are vulnerable to sulfate attacks during their service life, as sulfate ions react with cement hydration products to form expansive phases, generating internal stresses that cause mechanical degradation. In this study, a cementitious capillary crystalline waterproofing material (CCCW) was incorporated into concrete to mitigate sulfate ingress and enhance sulfate resistance. The evolution of compressive strength, ultrasonic pulse velocity, dynamic elastic modulus, and the microstructure of concrete was investigated in sulfate-exposed concretes with varying CCCW dosages and strength grades; the sulfate ion concentration profiles were also analyzed. The results indicate that the enhancement effect of CCCW on sulfate resistance declines progressively with increasing concrete strength. The formation of calcium silicate hydrate and calcium carbonate fills the pores of concrete, hindering the intrusion of sulfate solution. Moreover, the self-healing effect of concrete further inhibits the diffusion of sulfate ions through cracks, improving the sulfate resistance of concrete. These findings provide critical insights and practical guidance for improving concrete resistance to sulfate-induced deterioration. Full article

Calcium is an essential macronutrient for plant growth and development, and there is an optimal calcium concentration for plant growth. Calcium ion concentration changes create “calcium signals” that regulate plant growth through perception, decoding, transduction, and response processes. However, the mechanisms by which calcium signaling regulates photosynthesis are still not fully understood. In this study, Quercus acutissima seedlings were used to investigate the inhibitory effects of different concentrations of the calcium channel blocker lanthanum chloride (LaCl₃) on photosynthesis and the underlying mechanisms. The results show that increasing LaCl₃ concentration significantly decreased photosynthetic parameters, photosynthetic pigment contents, and photosynthetic product accumulation. Long-term water use efficiency decreased with increasing LaCl₃ concentration, while instantaneous water use efficiency initially increased and then decreased. Structural equation modeling analysis indicated that LaCl₃ concentration was significantly positively correlated with leaf calcium concentration in Quercus acutissima seedlings, while it was significantly negatively correlated with stomatal conductance, carotenoids, and soluble sugar content. The study concludes that LaCl₃ directly inhibits the photosynthetic physiological processes of Quercus acutissima seedlings by blocking calcium signaling, providing insights into the regulatory mechanisms of calcium signaling in plant photosynthesis and a theoretical basis for the cultivation and application of Quercus acutissima under varying environmental conditions. Full article

This study comprehensively evaluated the antimicrobial performance of copper ions against three bacterial species relevant to water systems: E. coli (ATCC 25922), P. aeruginosa (ATCC 27853), and S. epidermidis (ATCC 12228). Disinfection kinetics were determined at three copper concentrations (0.5, 1.5, and 3.3 mg/L) using the Gard model. E. coli exhibited the highest susceptibility, with inactivation rate constants of 0.63, 3.27, and 9.83, achieving complete inactivation at 3.3 mg/L. P. aeruginosa was the most resistant, showing values below 1.0 across all concentrations, while S. epidermidis displayed intermediate responses. Selected experiments further examined the influence of growth phase, temperature, and water chemistry. Exponential-phase cells were more sensitive than stationary-phase cultures, and higher temperatures (37 °C vs. 5 °C) significantly enhanced inactivation. Moderate bicarbonate (50 mg/L) improved bacterial removal by stabilizing soluble Cu²⁺ ions (2.60 lg reduction), whereas elevated calcium and magnesium (Ca²⁺ 100 mg/L, Mg²⁺ 50 mg/L) reduced effectiveness (≤2.10 lg reduction) through competitive interactions. In addition to culture-based methods, adenosine triphosphate (ATP) bioluminescence assays and flow cytometry (FCM) provided complementary insights, confirming early metabolic disruption and membrane damage prior to culturability loss in selected experiments. Full article

This study aimed to elucidate the physiological, biochemical, and transcriptional regulatory responses of potato plants to iron deficiency stress. Two potato varieties were selected for analysis: 05P (high tuber iron content) and CI5 (low tuber iron content). Tissue culture seedlings of both varieties were subjected to iron deficiency, and the effects on stem length, root length, fresh weight, soluble sugar and protein contents, as well as the activities of superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), and leaf chlorophyll content (SPAD) values were evaluated. Additionally, the impact of iron deficiency on zinc (Zn), magnesium (Mg), calcium (Ca), manganese (Mn), and copper (Cu) concentrations in different tissues were analyzed. Transcriptomic sequencing and quantitative real-time PCR (qRT-PCR) were performed on various seedling tissues. The results showed that iron deficiency significantly inhibited seedling growth and development, resulting in reduced plant height and fresh weight, increased root length, decreased leaf SPAD content, and elevated soluble sugar and protein concentration. SOD, POD, and MDA activities were also significantly increased. Elemental analysis revealed that iron deficiency enhanced the uptake and accumulation of Zn, Mg, Ca, Mn, and Cu across different tissues. Transcriptomic analysis identified differentially expressed genes (DEGs) significantly enriched in pathways related to photosynthesis, carbon metabolism, and ribosome function in roots, stems, and leaves. Iron deficiency induced the upregulation of H⁺-ATPase genes in roots (PGSC0003DMG400004101, PGSC0003DMG400033034), acidifying the rhizosphere to increase active iron availability. Subsequently, this was followed by the upregulation of FRO genes (PGSC0003DMG400000184, PGSC0003DMG400010125, PGSC0003DMG401009494, PGSC0003DMG401018223), which reduce Fe³⁺ to Fe²⁺, and activation of IRT genes, facilitating Fe²⁺ transport to various tissues. Iron deficiency also reduced SPAD content in leaves, negatively impacting photosynthesis and overall plant growth. In response, the osmotic regulation and antioxidant defense systems were activated, enabling the plant to mitigate iron deficiency stress. Additionally, the absorption and accumulation of other metal ions were enhanced, likely as a compensatory mechanism for iron scarcity. At the transcriptional level, iron deficiency induced the expression of genes involved in metal absorption and transport, as well as those related to photosynthesis, carbon metabolism, and ribosomal function, thereby supporting iron homeostasis and maintaining metabolic balance under stress conditions. Full article

A thermodynamically consistent model framework to describe ion transport in nanopores is presented. The continuum model unifies electro-diffusion and selective ion transport and extends the classical Poisson–Nernst–Planck (PNP) system for an idealized incompressible mixture by including finite ion size and solvation effects. Special emphasis is placed on the consistent modeling of the selectivity filter within the pore. It is treated as an embedded domain in which the constituents can change their chemical properties and mobility. Using this framework, we achieve good agreement with an experimentally observed current–voltage (IV) characteristic for an L-type selective calcium ion channel for a range of ion concentrations. In particular, we show that the model captures the experimentally observed anomalous mole fraction effect (AMFE). As a result, we find that calcium and sodium currents depend on the surface charge in the selectivity filter, the mobility of ions and the available space in the channel. Our results show that negative charges within the pore have a decisive influence on the selectivity of divalent over monovalent ions, supporting the view that AMFE can emerge from competition and binding effects in a multi-ion environment. Furthermore, the flexibility of the model allows its application in a wide range of channel types and environmental conditions, including both biological ion channels and synthetic nanopores, such as engineered membrane systems with selective ion transport. Full article

This study introduces a two-step treatment method for synthetic and real electric arc furnace dust (EAFD) wastewater, integrating sorption with Mg–Al layered double hydroxides (LDHs) and electrodialysis (ED). The hydrotalcite (LDH), mainly Mg₆Al₂(CO₃)OH₁₆·4H₂O (hydrotalcite-2H), was characterized by XRD, FTIR, SEM, and EDX, confirming its layered structure and ion-exchange capacity. Calcination at 550 °C was identified as optimal, enhancing sorption efficiency while retaining rehydration potential. Sorption tests demonstrated high effectiveness in removing multivalent ions, achieving over 99% elimination of Ca²⁺, SO₄²⁻, and Pb²⁺ ions and Cr from both synthetic and real wastewater. In contrast, monovalent ions such as Na⁺ and K⁺ were not effectively removed, except for partial removal of Cl⁻. To overcome this limitation, electrodialysis was applied in the second step, successfully targeting the remaining monovalent ions and achieving more than 95% conductivity reduction. A key challenge of ED, salt precipitation caused by calcium and sulphate in the concentrate, was effectively mitigated by the prior LDH treatment. The combined process minimized scaling risks, improved overall ion removal (above 97% for Na⁺ and K⁺), and produced low-salinity effluents (0.84 mS cm⁻¹), suitable for reuse in hydrometallurgical operations. These findings demonstrate that coupling LDH sorption with electrodialysis provides a sustainable and efficient strategy for treating high-salinity industrial wastewaters, particularly those originating from EAFD processes. Full article