Search Results (5,031)

Alginate is an important natural biopolymer and metal ion-induced gelation is one of its most significant functional properties. Alginate-based hydrogels crosslinked with metal ions are commonly utilized in the food, biomedical, tissue engineering, and environment fields. The process of metal ion-induced alginate gelation has been the subject of thorough research over the last few decades. This review aims to summarize the mechanisms of alginate hydrogels induced by different cations (primarily including Ca²⁺, Ba²⁺, Cu²⁺, Sr²⁺, Fe²⁺/Fe³⁺, and Al³⁺). Metal ion-induced alginate gelation shows different preferences for α-L-guluronic acid (G), β-D-mannuronic acid (M), and GM blocks. Some metal ions can also selectively bind to the carboxyl groups of guluronic acid. The properties and applications of these alginate-based hydrogels are also discussed. The primary objective of this review is to provide useful information for exploring the practical applications of alginate. Full article

A stacked nanocomposite zinc-tin oxide/single-walled carbon nanotubes (ZTO/SWNTs) active layer was fabricated for thin-film transistors (TFTs) as an alternative to the conventional single-layer structure of mixed ZTO and SWNTs. The stacked nanocomposite of the solution-processed TFTs was prepared using UV/O₃ treatment and multiple annealing steps for each layer. The electrical properties of the stacked device were superior to those of the single-layer TFT. The ZTO/SWNT TFT, fabricated using a stacked structure with ZTO on the top and SWNT at the bottom layer, showed a significant improvement in the field-effect mobility of 15.37 ${\mathrm{cm}}^2/\mathrm{V}·\mathrm{s}$ (factor of three increase) and an I_on/I_off current ratio of 8.83 × ${10}^8$ with improved hysteresis. This outcome was attributed to the surface treatment and multiple annealing of the selected active layer, resulting in improved contact and a dense structure. This was also attributed to the controlled dispersion of SWNT, as electron migration paths without dispersants. This study suggests the potential expansion of applications, such as flexible electronics and low-cost fabrication of TFTs. Full article

Efficient removal of iron and aluminum impurities is critical for the extraction of lithium and rubidium from zinnwaldite, a lithium-bearing mineral. In this study, solvent extraction using P507 was employed to remove iron and aluminum from zinnwaldite leaching solutions. However, stripping iron from the organic phase proved challenging due to the strong interaction between iron ions and the extractant. To address this, a novel reduction stripping method was developed using ascorbic acid (AA) as a reductant. This method exploits the reduction of Fe³⁺ to Fe²⁺ in the aqueous phase, weakening the binding between iron ions and the organic phase, thus enabling efficient stripping. The optimized process achieved over 99.99% removal of iron and aluminum impurities. Subsequently, rubidium was selectively extracted using t-BAMBP, with a total recovery rate of 88.53%. Scaling-up experiments confirmed the feasibility of the process for industrial applications, demonstrating high efficiency and reagent recyclability. This study offers a promising approach for the efficient extraction and separation of valuable metals from zinnwaldite, with potential for broader applications in metal processing. Full article

A novel rhodamine-6G derivative RdN was synthesized by condensing rhodamine glyoxal and 3-hydroxy-2-naphthoic hydrazide using a microwave irradiation-assisted reaction. Colorimetric and photophysical studies have demonstrated that the molecule produced can selectively sense Pb²⁺ and Cu²⁺ ions in a solution of CH₃CN/H₂O (9:1, v/v). The spirolactam ring of RdN opens upon complexation with the cations, forming a highly fluorescent complex and a visible color change in the solution. The compound RdN was further studied with the help of computational methods such as the Density Functional Theory (DFT) method and time-dependent density theory (TD-DFT) calculations to study the binding interactions and properties of the molecule. DFT calculations and job plot data supported the 2:1 complex formation between RdN and Pb²⁺/Cu²⁺. The limit of detection for Pb²⁺ was determined to be 0.112 µM and 0.130 µM for Cu²⁺. The probe RdN was applied to the image of Pb²⁺ and Cu²⁺ ions in living cells and is safe for biomedical applications. It is used to monitor Pb²⁺ in environmental water samples. Full article

Polymers exhibiting ion-conduction capabilities are essential components of water-purifying devices. These polymers not only transport selective ions but are also mechanically robust; thus, they can be processed as membranes. In this review, we highlight major acidic polymers and their engineered morphologies and optimized properties, including metal selectivity and water permeation or retention. Crucial phenomena, such as self-assembly in acid-group-functionalized polymers for driving water transportation, are discussed. It was observed that the phosphonic acid groups containing polymers are rather suitable for the selective adsorption of toxic metals, and thus, are superior to their sulfonated counterparts. Additionally, due to their amphoteric nature, phosphonated polymers displayed several modes of metal complexations, which makes them appropriate for eliminating a wide range of metals. Further observation indicates that aromatic-acid-functionalized polymers are more durable. Temperature- and pH-responsive polymers were also found to be promising candidates for a controlled water-treatment process. Nevertheless, considering the morphology, water retention, and metal adsorption, acid-functionalized polymers, especially phosphonated ones, have the potential to remain as the materials of choice after additional advancements. Further perspectives regarding improvements in acidic polymers and their fabricated membranes for water treatment are presented. Full article

The early monitoring of cardiovascular biomarkers is essential for the prevention and management of some cardiovascular diseases. Here, we present a novel, compact, and highly integrated skin electrode as a mechanical–electrochemical dual-model E-skin, designed for the real-time monitoring of heart rate and sweat ion concentration, two critical parameters for assessing cardiovascular health. As a pressure sensor, this E-skin is suitable for accurate heart rate monitoring, as it exhibits high sensitivity (25.2 pF·kPa⁻¹), a low detection limit of 6 Pa, and a rapid response time of ~20 ms, which is attributed to the iontronic sensing interface between the skin and the electrode. Additionally, the electrode functions as a potassium ion-selective electrode based on chemical doping, achieving an enhanced response of 11 mV·mM⁻¹. A test based on the real-time monitoring of a subject riding an indoor bike demonstrated the device’s capability to monitor heart rate and sweat potassium ion levels reliably and accurately. This advancement in wearable technology offers significant potential for enhancing patient care based on the early detection and proactive management of cardiovascular conditions. Full article

To overcome the disadvantage of difficult recovery of powder catalysts and improve catalyst utilization, the selection of foam metal substrates as supports can reduce the difficulty of material recovery and effectively inhibit the leaching of metal ions. Herein, CoMnNi-layered double hydroxide (LDH) derived from Co-Mn ZIF was immobilized onto nickel foam (NF) through in situ synthesis. The results of XRD and SEM analyses of the samples indicated that the LDH was successfully grown on the nickel foam matrix, and the material could maintain its original morphology to the maximum extent after loading. By comparing the XPS of the material before and after the reaction, it was confirmed that the surface hydroxyl group and C=O of the material were involved in the activation of peroxymonosulfate (PMS). The results of the quenching reaction showed that SO₄^•− and ¹O₂ are the main active substances in the oxidation of enrofloxacin (ENR). When the dosage of NF@CoMnNi-LDH was 0.4 g/L, the pH of the solution was 6.82, and when the dosage of PMS was 2.0 mM, the degradation rate of ENR reached 82.6% within 30 min. This research offers novel insights into the degradation of antibiotics from water using a monolithic catalyst supported by metal foam. Full article

Citrus peel essential oils (CPEOs) have demonstrated substantial medicinal potential for glioblastoma treatment because of their extensive antitumor effects, low potential for drug resistance, and ability to cross the human blood–brain barrier. In this study, the chemical compositions of five CPEOs were analyzed via gas chromatography–mass spectrometry (GC-MS). CCK8 assays were used to evaluate the ability of five CPEOs to inhibit U251 human glioblastoma cells, and XLB and RA were selected for further investigation. Through wound healing assays and cell cycle and apoptosis analyses via flow cytometry, it was revealed that these CPEOs inhibited cell migration, arrested the cell cycle at G1/G0, and induced apoptosis with similar levels of inhibition. After CPEOs treatment, the intracellular Ca²⁺ content and reactive oxygen species levels in U251 cells increased significantly, whereas the mitochondrial membrane potential decreased. Additionally, the antioxidant enzyme system (SOD, POD, CAT, and GR) and the nonenzymatic defense system (GSH) were inhibited, leading to an increase in lipid peroxidation. qRT–PCR indicated the significant upregulation of intracellular calcium ion signaling pathways and the upregulation of mitochondrial apoptosis-related genes. Additionally, the activation of calcicoptosis-related indicators induced by the CPEOs could be reversed by inhibitor treatment, confirming that both of the selected CPEOs inhibit tumors by activating calcicoptosis-related pathways. These findings highlight the immense potential of CPEOs in healthcare and pharmaceutical applications by not only providing a scientific basis for the potential application of CPEOs in the treatment of glioblastoma but also offering new insights for the development of novel antitumor drugs. Full article

This work provides theoretical calculations of fluorescence angular distribution and polarization within an XUV pump–XUV probe scheme designed for determining ultra-short lifetimes of highly charged heavy ions. The initial pumping leads to a non-zero alignment in the excited levels. After the probing stage, the anisotropies in angular distribution and polarization of subsequent fluorescence are significantly enhanced due to the existence of a previous alignment. Furthermore, two-photon sequential excitation from a ground state with zero angular momentum to a level with angular momentum one by two aligned linearly polarized photon beams is strictly prohibited by the selection rules and may be used as a diagnostic tool to determine beam misalignment. The present approach is based on the density matrix and statistical tensor framework. We provide the analytical form for the alignment parameters caused by successive photoexcitation either with linearly polarized photon beams, or with unpolarized photons. The analytical results can generally be used to compute angular distribution asymmetry parameters and linear polarization of subsequent fluorescence for a large array of atomic systems used in pump–probe experiments. Full article

Background: Drosophila suzukii is a worldwide invasive species with serious economic impacts. Herein, we are presenting the first project of sequencing and assembling the whole genomes of two lines of D. suzukii derived from Romanian local populations using exclusively Oxford Nanopore Technologies data. Methods: We implemented both MinION and Flongle flow-cells and tested the impact of various basecalling models and assembly strategies on the quality of the sought-after representative genome assemblies. Results: We demonstrate that the sup-basecalling model significantly improved the read quality and that adding a relatively small collection of reads had a significant positive impact over the assembly quality. The novel dScaff bioinformatics prototype tool allowed us to perform sequence-level quality tests, as well as to represent assembly selections and display both the contig redundancy and the repeats-enriched genomic sub-sequences. Moreover, we used dScaff to propose a minimal assembly variant corresponding to one of our lines, GB-ls-coga4, which assured a basic linear coverage of the genome and exhibited quality parameters comparable with those particular to the current reference genome assembly. Conclusions: The study presents the first sequencing and assembly of a D. suzukii line in Romania and argues the efficiency of long-read sequencing strategies. Full article

This article proposes various new approximate analytical solutions of the boundary value problem for the non-stationary system of Nernst–Planck–Poisson (NPP) equations in the diffusion layer of an ideally selective ion-exchange membrane at overlimiting current densities. As is known, the diffusion layer in the general case consists of a space charge region and a region of local electroneutrality. The proposed analytical solutions of the boundary value problems for the non-stationary system of Nernst–Planck–Poisson equations are based on the derivation of a new singularly perturbed nonlinear partial differential equation for the potential in the space charge region (SCR). This equation can be reduced to a singularly perturbed inhomogeneous Burgers equation, which, by the Hopf–Cole transformation, is reduced to an inhomogeneous singularly perturbed linear equation of parabolic type. Inside the extended SCR, there is a sufficiently accurate analytical approximation to the solution of the original boundary value problem. The electroneutrality region has a curvilinear boundary with the SCR, and with an unknown boundary condition on it. The article proposes a solution to this problem. The new analytical solution methods developed in the article can be used to study non-stationary boundary value problems of salt ion transfer in membrane systems. The new analytical solution methods developed in the article can be used to study non-stationary boundary value problems of salt ion transport in membrane systems. Full article

This work focuses on the preparation and application of silver nanoparticles/organophilic clay/polyethylene glycol for the catalytic reduction of the contaminants methylene blue (MB) and 4-nitrophenol (4-NP) in a simple and binary system. Algerian clay was subjected to a series of treatments including acid treatment, ion exchange with the surfactant hexadecyltrimethylammonium bromide (HTABr), immobilization of polyethylene glycol polymer, and finally dispersion of AgNPs. The molecular weight of polyethylene glycol was varied (100, 200, and 4000) to study its effect on the stabilization of silver nanoparticles (AgNPs) and the catalytic activity of the resulting samples. The results showed that the catalyst with the highest molecular weight of polyethylene glycol had the highest AgNP content. Catalyst mass, NaBH₄ concentration, and type of catalyst were shown to have a significant influence on the conversion and rate constant. The material with the highest silver nanoparticle content was identified as the optimal catalyst for the reduction of both pollutants. The measured rate constants for the reduction of methylene blue (MB) and 4-nitrophenol (4-NP) were 164 × 10⁻⁴ s⁻¹ and 25 × 10⁻⁴ s⁻¹, respectively. The reduction of MB and 4-NP in the binary system showed high selectivity for MB dye, with rate constants of 64 × 10⁻⁴ s⁻¹ and 9 × 10⁻⁴ s⁻¹ for MB and 4-NP, respectively. The reuse of the best catalyst via MB dye reduction for four cycles showed good results without loss of performance. Full article

Direct lithium extraction from unconventional resources requires the development of effective adsorbents. Crown ether-containing materials have been reported as promising structures in terms of lithium selectivity, but data on adsorption in real, highly saline brines are scarce. Crown ether-grafted graphene oxides were synthesized using 2-hydroxymethyl-12-crown-4, hydroxy-dibenzo-14-crown-4 and epichlorohydrin as a source of anchoring groups. The obtained carbonaceous materials were used to prepare chitosan–polyvinyl alcohol composites. The prepared materials (and intermediate products) were characterized using FTIR, XRD, Raman spectroscopy and SEM-EDS methods. Adsorption tests were performed in a pure diluted LiCl solution ([Li] = 200 mg/kg) as well as in a real, highly saline oilfield brine ([Li] ≈ 220 mg/kg), and the distribution coefficients (K_d) were determined. The obtained results show that K_d in pure LiCl solution was in the range of 0.9–75.6, while in brine it was in the range of 0.2–2.3. The study indicates that the high affinity for lithium in pure LiCl solution is mostly associated with the non-selective interaction of lithium ions with the graphene oxide matrix (COOH groups). It was also shown that the application of dibenzo-14-crown-4 moiety to graphene oxide modification groups increases the affinity of the composite material for lithium ions compared to an analogous material containing 12-crown-4-ether groups. Full article

An accurate prognosis of the marine lithium-ion battery capacity is significant in guiding electric ships’ optimal operation and maintenance. Under real-world operating conditions, lithium-ion batteries are exposed to various external factors, making accurate capacity prognostication a complex challenge. The paper develops a marine lithium-ion battery capacity prognostic method based on ICPO-Bi-LSTM under dynamic operating conditions to address this. First, the battery is simulated according to the actual operating conditions of an all-electric ferry, and in each charge/discharge cycle, the sum, mean, and standard deviation of each parameter (current, voltage, energy, and power) during battery charging, as well as the voltage difference before and after the simulated operating conditions, are calculated to extract a series of features that capture the complex nonlinear degradation tendency of the battery, and then a correlation analysis is performed on the extracted features to select the optimal feature set. Next, to address the challenge of determining the neural network’s hyperparameters, an improved crested porcupine optimization algorithm is proposed to identify the optimal hyperparameters for the model. Finally, to prevent the interference of test data during model training, which could lead to evaluation errors, the training dataset is used for parameter fitting, the validation dataset for hyperparameter adjustment, and the test dataset for the model performance evaluation. The experimental results demonstrate that the proposed method achieves high accuracy and robustness in capacity prognostics of lithium-ion batteries across various operating conditions and types. Full article

The contamination of water by heavy metals poses an escalating risk to human health and the environment, underscoring the critical need for efficient removal methods to secure safe water resources. This study evaluated the performance of four cationic exchange materials (labeled “PS—DVB”, “PA—DVB”, “TFSA”, and “OGL”) in removing or harvesting metals such as copper, silver, lead, cobalt, and nickel from aqueous solutions, several of which are precious and/or classified as Critical Raw Materials (CRMs) due to their economic importance and supply risk. The objective was to screen and benchmark the four ion exchange materials for water treatment applications by investigating their metal sequestration capacities. Experiments were conducted using synthetic solutions with controlled metal concentrations, analyzed through ICP-OES, and supported by kinetic modeling. The adsorption capacities (qe) obtained experimentally were compared with those predicted by pseudo-first-order and pseudo-second-order models. This methodology enables high precision and reproducibility, validating its applicability for assessing ion exchange performance. The results indicated that PS—DVB and PA—DVB resins proved to be of “wide range”, exhibiting high efficacy for most of the metals tested, including CRM-designated ones, and suggesting their suitability for water purification. Additionally, the second-life Nafion-based “TFSA” material demonstrated commendable performance, highlighting its potential as a viable and technologically advanced alternative in water treatment. Lastly, the lignin-based material, “OGL”, representing the most innovative and sustainability apt option, offered relevant performance only in selected cases. The significant differences in performance among the resins underscore the impact of structural and compositional factors on adsorption efficiency. This study offers valuable insights for investigating and selecting new sustainable materials for treating contaminated water, opening new pathways for targeted and optimized solutions in environmental remediation. Full article