Search Results (948)

Machilus thunbergii Siebold & Zucc. is recognized as an excellent tree species for landscaping and shelter forest. Excessive drought can affect the changes of physiological and biochemical substances in plants. However, little is known at present regarding the drought stress of M. thunbergii seedlings. In this paper, matrix water content, the anatomical structure of leaves, relative water content of leaves, and physiological characteristics index of leaves under droughting stress were dynamically observed. Droughting stress led to the wilting of M. thunbergii leaves, gradual closure of stomata on leaf epidermis, increases in stomatal density, gradual loosening of leaf cell structure arrangement, a thickening in leaf palisade tissue, and reductions in spongy tissue. Droughting stress caused the relative water content of the cultivation substrate to decline, the cultivation substrate reached the moderate drought level, and the seedlings began to die. Droughting stress led to the destruction of activity and balance of the leaf protective enzyme system, excessive accumulation of free radicals, the destruction of enzyme structure and function, and the production of lipid peroxidation product MDA. Droughting stress reduced the relative water content of leaves as a whole, the content of osmotic adjustment substances proline and soluble protein continued to decline, and a large number of electrolyte leakage in cells, causing serious damage to seedlings. Full article

In this study, the electrochemical corrosion behavior of TiAlZrTaNb nitride thin films deposited on 304 stainless steel substrates was investigated. The thin films were synthesized using high-power impulse magnetron sputtering (HiPIMS) and are classified as high-entropy alloys (HEAs). The microstructure, morphology, and chemical composition of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS), respectively. Corrosion resistance was evaluated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests, employing tap water, acetic acid, and citric acid solutions at room temperature as electrolytes. The results demonstrated that the TiAlZrTaNbN coating exhibits a dense and homogeneous structure with a uniform elemental distribution. XRD analysis revealed the presence of face-centered cubic (FCC) crystalline phases, which significantly contribute to the coating’s corrosion resistance. Furthermore, the coating displayed exceptional corrosion performance in both acetic acid and citric acid electrolytes—simulating food environments with a pH ≤ 4.5—as revealed by a substantial reduction in corrosion current density and a positive shift in corrosion potential. These findings provide valuable insights into the properties of TiAlZrTaNbN coatings and underscore their potential for enhancing the durability of mechanical components employed in the food industry. Full article

Copper contamination in the environment poses significant risks to both soil and human health, making the need for reliable monitoring methods crucial. In this study, we report the use of the EmStat Pico module as potentiostat to develop a portable electrochemical biosensor for copper detection, utilizing yeast Saccharomyces cerevisiae cells immobilized on a polydopamine (PDA)-coated screen-printed electrode (SPE). By optimizing the sensor design with a horizontal assembly and the volume reduction in the electrolyte solution, we achieved a 10-fold increase in current density with higher range of copper concentrations (0–300 µM CuSO₄) compared to traditional (or previous) vertical dipping setups. Additionally, the use of genetically engineered copper-responsive yeast cells further improved sensor performance, with the recombinant strain showing a 1.7-fold increase in current density over the wild-type strain. The biosensor demonstrated excellent reproducibility (R² > 0.95) and linearity over a broad range of copper concentrations, making it suitable for precise quantitative analysis. To further enhance portability and usability, a Bluetooth-enabled electrochemical platform was integrated with a web application for real-time data analysis, enabling on-site monitoring and providing a reliable, cost-effective tool for copper detection in real world settings. This system offers a promising solution for addressing the growing need for efficient environmental monitoring, especially in agriculture. Full article

Tick infestation represents a significant constraint on livestock productivity in Saudi Arabia; however, there remains a substantial gap in research addressing tick species diversity, distribution, and their direct effects on milk production. This study aimed to morphologically and molecularly identify tick species infesting dairy cattle, quantify the impact of tick infestation on milk yield and composition, and contribute to the limited understanding of tick ecology and its economic implications in the region. Ticks were collected from infested cows and identified morphologically using taxonomic keys. Molecular identification was performed via PCR amplification of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Milk production and quality parameters were assessed in tick-infested and healthy cows in Hafar Al-Batin, Eastern Saudi Arabia. Morphological and genetic analyses confirmed Hyalomma anatolicum as the predominant tick species in the study area, with COI sequences showing high similarity to regional isolates. Tick-infested cows exhibited substantial reductions in milk yield, fat, calcium, and potassium levels, indicating significant metabolic disruptions. Blood biochemical analysis revealed elevated levels of liver enzymes [aspartate aminotransferase (AST) increased by 238.6%, gamma-glutamyl transferase (GGT) by 155.7%], renal markers [creatinine increased by 788.9%, urea by 130.0%], and electrolyte imbalances [serum calcium decreased by 39.5%, potassium by 45.2%]. Hematological findings included increased white blood cell (WBC) and red blood cell (RBC) counts by 44.9% and 124.7%, respectively, along with a 53.1% decrease in hemoglobin (HGB), suggesting a systemic inflammatory response and possible anemia. This study is among the first to genetically confirm the presence of H. anatolicum in Hafar Al-Batin using molecular tools, thereby enhancing the accuracy of species-level identification and highlighting the physiological impact of tick burden on dairy productivity. Full article

To develop a CO₂-free process for recovering Fe and Zn metals from electric arc furnace (EAF) dust, this study investigated the molten oxide electrolysis of various Fe₂O₃–ZnO mixtures in a B₂O₃–Na₂O electrolyte. Electrolysis was conducted using an Fe cathode and Pt anode at 1173 K by applying cell voltages that were determined based on thermodynamic calculations and cyclic voltammetry measurements. When electrolysis was conducted at a cell voltage of 1.1 V, the selective reduction of Fe oxide to Fe metal was observed without ZnO reduction. However, when 1.6 V was applied, the co-reduction of Fe oxide and ZnO to the Fe–Zn alloy was observed. In the vacuum distillation of the Fe–Zn alloy at 1000–1200 K, Zn metal with a purity of ≥99.996% was obtained with a recovery efficiency of ≥99.9%, under certain conditions. This study demonstrates the feasibility of recovering Fe and Zn from EAF dust using low-temperature molten oxide electrolysis and subsequent vacuum distillation. Full article

The advancement of efficient energy conversion and storage technologies is fundamentally linked to the development of electrochemical systems, including fuel cells, batteries, and electrolyzers, whose performance depends on key electrocatalytic reactions: hydrogen evolution (HER), oxygen evolution (OER), oxygen reduction (ORR), carbon dioxide reduction (CO₂RR), and nitrogen reduction (NRR). Beyond catalyst design, the electrolyte microenvironment significantly influences these reactions by modulating charge transfer, intermediate stabilization, and mass transport, making electrolyte engineering a powerful tool for enhancing performance. This review provides a comprehensive analysis of how fundamental electrolyte properties, including pH, ionic strength, ion identity, and solvent structure, affect the mechanisms and kinetics of these five reactions. We examine in detail how the electrolyte composition and individual ion contributions impact reaction pathways, catalytic activity, and product selectivity. For HER and OER, we discuss the interplay between acidic and alkaline environments, the effects of specific ions, interfacial electric fields, and catalyst stability. In ORR, we highlight pH-dependent activity, selectivity, and the roles of cations and anions in steering 2e⁻ versus 4e⁻ pathways. The CO₂RR and NRR sections explore how the electrolyte composition, local pH, buffering capacity, and proton sources influence activity and the product distribution. We also address challenges in electrolyte optimization, such as managing competing reactions and maximizing Faradaic efficiency. By comparing the electrolyte’s effects across these reactions, this review identifies general trends and design guidelines for enhancing electrocatalytic performance and outlines key open questions and future research directions relevant to practical energy technologies. Full article

The chromium-free oxide precursor strategy effectively avoids chromium volatilization and electrode contamination in metal-supported solid oxide fuel cells (MS-SOFCs), while enabling high-temperature co-sintering in air to simplify the fabrication process. However, the drastic microstructural coarsening, dimensional shrinkage, and thermal expansion mismatch with adjacent components of such substrates during high-temperature sintering, reduction, and thermal cycling collectively contribute to the interfacial instability and structural degradation of MS-SOFCs. Herein, we address these issues by incorporating a small amount of Gd_0.1Ce_0.9O_1.95 (GDC) to the NiO-Fe₂O₃ (NFO) substrate. The incorporation of GDC significantly enhances the sintering compatibility and reduction stability of the MS-SOFCs, alleviating the stress-induced warping and distortion. Moreover, the GDC phase has a pinning effect to suppressing the coarsening of the substrates during high-temperature sintering and reduction processes, enhancing mechanical integrity and structural robustness of the single cell. With 15 wt% GDC incorporated into the NiFe substrate, the corresponding MS-SOFC with GDC electrolyte film achieves a peak power density of 0.56 W cm⁻² at 600 °C, along with markedly improved structural integrity and operational reliability. This work demonstrates a viable pathway for designing heterophase-engineered supports with matched thermomechanical properties, offering promising prospects for enhancing the durability of MS-SOFCs. Full article

Background: Hyperventilation Syndrome (HVS) is a well-recognized physiological consequence of acute anxiety, often resulting in respiratory alkalosis and subsequent electrolyte imbalances. Among these, a reduction in ionized calcium levels can lead to neuromuscular irritability and electrocardiographic abnormalities such as QTc prolongation. Although well-documented in specific settings, including autism spectrum disorders and drug-induced crises, such complications are rarely described in otherwise healthy pediatric patients presenting with isolated anxiety episodes. This report aims to raise awareness of anxiety-driven somatic manifestations, particularly in the context of the rising prevalence of mental health disorders among children and adolescents. Methods: We report the case of a previously healthy 10-year-old girl presenting to the emergency department with acute agitation and hyperventilation. Clinical examination revealed neuromuscular symptoms, including Trousseau’s sign and flexion posture. Initial laboratory testing and arterial blood gas analysis indicated respiratory alkalosis with decreased ionized calcium levels, and a resting ECG showed QTc prolongation (510 ms). Treatment included intravenous midazolam, a balanced electrolyte solution, and oral bromazepam during intensive observation with cardiac monitoring. Results: The patient’s symptoms progressively improved following anxiolytic and supportive therapy. Electrolyte abnormalities normalized within 48 h, with complete resolution of the prolonged QTc (430 ms). No arrhythmias or other complications occurred. Outpatient psychological follow-up was arranged upon discharge. Conclusions: This case underscores the importance of considering anxiety as a primary etiology in pediatric patients with apparent metabolic or cardiac abnormalities. Early psychiatric recognition and targeted supportive care can prevent overtreatment and reduce the burden on emergency and cardiologic resources. Full article

In this paper, 8 mol% yttria cubic stabilized zirconia (8YCSZ) composites with reduced graphene oxide (rGO) contents up to 10 vol% were consolidated by spark plasma sintering (SPS) at two different temperatures with the aim of evaluating the relationship of their electrical properties with the graphene content, the rGO crystallinity, and the microstructural features. Successful in situ reduction of GO was accomplished during SPS, and highly densified composites with homogeneous rGO distribution, even at the highest contents, were obtained. The electrical properties were analyzed using impedance spectroscopy. Measurements were taken up to 700 °C, revealing an inductive response for the composites with 5 and 10 vol% rGO and a capacitive response for the composites with 1 and 2.5 vol% rGO. The results indicate that, along with the ionic conduction typical of zirconia, there are additional polarization mechanisms associated with the presence of graphene at ceramic grain boundaries that substantially modify the impedance response. A minor electronic conductivity contribution was identified in the composites below the percolation threshold. These characteristics make the 8YCSZ composites promising candidates for application as SOFC components, as ceramic interconnects when the graphene content is above the percolation threshold, or as electrolytes when the graphene content is below this limit. Full article

In recent years, high temperature and drought have severely impacted the growth and development of loquat [Eriobotrya japonica (Thunb.) Lindl.] plants. Although dopamine can improve the stress resistance of plants, its role in combined stress requires further exploration. This study investigated the alleviative effect and mechanism of exogenous dopamine on loquat seedlings subjected to the combined stress of high temperature and drought. The combined stress significantly reduced root viability, photosynthetic pigment content, and net photosynthetic rate (Pn) while markedly increasing reactive oxygen species (ROS) levels, thiobarbituric acid-reactive substances (TBARS) content, and electrolyte leakage (EL). The seedlings exhibited pronounced wilting symptoms, along with markedly reduced root surface area and volume. Dopamine treatment significantly alleviated combined stress-induced damage. This mitigation was manifested through substantially enhanced root viability, photosynthetic pigment content, Pn, antioxidant enzyme activities, and osmotic adjustment substances concomitantly with marked reductions in ROS, TBARS content, and EL. Dopamine significantly reduced seedling wilting severity and improved root morphological parameters. This study demonstrates that dopamine enhances loquat seedlings’ tolerance to combined stress through coordinated mechanisms: maintaining photosynthetic pigments and improving stomatal conductance to sustain photosynthetic efficiency, enhancing antioxidant enzyme activity and ROS scavenging capacity to mitigate oxidative damage, and promoting osmotic solute accumulation for osmotic potential regulation. Full article

Soybean (Glycine max (L.) Merrill) is highly sensitive to water deficit, particularly during the vegetative phase, when morphological and metabolic plasticity support continued growth and photosynthetic efficiency. We applied eleven water regimes, from full irrigation (W100) to total water withholding (W0), to plants grown under controlled conditions. After 14 days, we quantified morphophysiological, biochemical, leaf optical, gas exchange, and chlorophyll a fluorescence traits. Drought induces significant reductions in leaf area, biomass, pigment pools, and photosynthetic rates (A, g_s, ΦPSII) while increasing the levels of oxidative stress markers (electrolyte leakage, ROS) and proline accumulation. OJIP transients and JIP test metrics revealed reduced electron-transport efficiency and increased energy dissipation for many parameters under severe stress. Principal component analysis (PCA) clearly separated those treatments. PC1 captured growth and water status variation, whereas PC2 reflected photoprotective adjustments. These data show that progressive drought limits carbon assimilation via coordinated diffusive and biochemical constraints and that the accumulation of proline, phenolics, and lignin is associated with osmotic adjustment, antioxidant buffering, and cell wall reinforcement under stress. The combined use of hyperspectral sensors, gas exchange, chlorophyll fluorescence, and multivariate analyses for phenotyping offers a rapid, nondestructive diagnostic tool for assessing drought severity and the possibility of selecting drought-resistant genotypes and phenotypes in a changing stress environment. Full article

The dual benefit of wastewater and microalgal biomass is a major advantage of high-rate algal ponds, enabling the environmental valorization of these byproducts. This research explored the effect of treated wastewater on the agri-food species Hordeum vulgare (L.) and its associated weed, Emex spinosa (L.) Campd., along with the effects of algal biomass (primarily composed of Closterium, Chlorella, and Scenedesmus spp.) and Diplotaxis harra leaf powder. Initial pot trials applied microalgae and D. harra at 2, 4, and 6 g·kg⁻¹ soil, also confirming that the treated wastewater met reuse standards and did not affect plant growth. The combined treatment at 4 g·kg⁻¹ led to the highest H. vulgare increases in fresh weight (162.71%), root length (73.75%), and shoot length (72.87%), while reducing E. spinosa shoot and root lengths by 30.79% and 52.18%, and fresh weight by 68.24%. Subsequent field experiments using 1.26 t ha⁻¹ of 0.5-cm-applied D. harra and microalgae powders enhanced H. vulgare growth, while reducing the growth of E. spinosa. The reduction in E. spinosa growth was associated with increased electrolyte leakage and malondialdehyde content. These results support the integration of high-rate algal ponds into agriculture, promoting water reuse and reducing reliance on synthetic fertilizers and herbicides in barley production. Full article

In the context of chlorate’s application as a cathodic reagent of power sources, the mechanism of its electroreduction has been studied in electrochemical cells under diffusion-limited current conditions with operando spectrophotometric analysis. Prior to electrolysis, the electrolyte is represented as an aqueous mixed NaClO₃ + H₂SO₄ solution (both components being non-electroactive within the potential range under study), without addition of any external electroactive catalyst. In the course of potentiostatic electrolysis, both the cathodic current and the ClO₂ concentration demonstrate a temporal evolution clearly pointing to an autocatalytic mechanism of the process (regions of quasi-exponential growth and of rapid diminution, separated by a narrow maximum). It has been substantiated that its kinetic mechanism includes only one electrochemical step (chlorine dioxide reduction), coupled with two chemical steps inside the solution phase: comproportionation of chlorate anion and chlorous acid, as well as chlorous acid disproportionation via two parallel routes. The corresponding set of kinetic equations for the concentrations of Cl-containing solute components (ClO₃⁻, ClO₂, HClO₂, and Cl⁻) has been solved numerically in a dimensionless form. Optimal values of the kinetic parameters have been determined via a fitting procedure with the use of non-stationary experimental data for the ClO₂ concentration and for the current, taking into account the available information from the literature on the parameters of the chlorous acid disproportionation process. Predictions of the proposed kinetic mechanism agree quantitatively with these experimental data for both quantities within the whole time range, including the three characteristic regions: rapid increase, vicinity of the maximum, and rapid decrease. Full article

Metal–air batteries have excellent theoretical energy density and economic advantages through abundant anode materials and open cathode structures. However, the actual energy efficiency of metal–air batteries is much lower than the theoretical value due to the effect of polarization voltage during battery operation, limiting the power output and thus hindering their practical application. This review systematically dissects the origins of polarization: slow oxygen reduction/evolution reaction (ORR/OER) kinetics, interfacial resistance, and mass transfer bottlenecks. We highlight cutting-edge strategies to mitigate polarization, including atomic-level engineering of air cathodes (e.g., single-atom catalysts, low Pt catalysts), biomass-derived 3D porous electrodes, and electrolyte innovations (additives to inhibit corrosion, solid-state electrolytes to improve stability). In addition, breakthroughs in metal–H₂O₂ battery design using concentrated liquid oxygen sources are discussed. Together, these advances alleviate the battery polarization bottleneck and pave the way for practical applications of metal–air batteries in electric vehicles, drones, and deep-sea devices. Full article

In this study, cerium with different ratios (x = 0 (zero), 0.1, 0.15, 0.5) was added to the PrMn structure as an A-site material to evaluate characteristic behavior as a potential cathode material for solid oxide fuel cells. The Pr_xCe_1−xMnO_3−δ electrocatalysts were synthesized using the sol–gel combustion method and were assessed for their electrochemical, phase, and structural properties, as well as desorption and reducibility capabilities. Phase changes, from orthorhombic to cubic structures observed upon cerium additions, were evaluated via the X-Ray diffraction method. X-Ray photoelectron spectroscopy (XPS) showed the valence states of the surface between the Ce⁴⁺/Ce³⁺ and Pr⁴⁺/Pr³⁺ redox pairs, while oxygen temperature programmed desorption (O₂-TPD) analysis was used to evaluate the oxygen adsorption and desorption behavior of the electrocatalysts. Redox characterization, evaluated via hydrogen atmosphere temperature-programmed reduction (H₂-TPR), revealed that a higher cerium ratio in the structure lowered the reduction temperature, suggesting a better dynamic oxygen exchange capability at a lower temperature for the Pr_0.5Ce_0.5MnO_3−δ catalyst compared to the electrochemical behavior analysis by the electrochemical impedance spectroscopy method. Moreover, the symmetrical cell tests with Pr_0.5Ce_0.5MnO_3−δ electrodes showed that, when combined with scandia-stabilized zirconia (ScSZ) electrolyte, the overall polarization resistance was reduced by approximately 28% at 800 °C compared to cells with yttria-stabilized zirconia (YSZ) electrolyte. Full article