Search Results (473)

Access to clean water is a pressing global concern and membrane technologies play a vital role in addressing this challenge. Thin-film composite membranes prepared via interfacial polymerization (IPol) using meta-phenylenediamine (MPD) and trimesoyl chloride (TMC) exhibit excellent separation performance, but face limitations such as fouling and low hydrophilicity. This study investigated the interaction between MPD and sulfonated zinc phthalocyanine, Zn(SO₂⁻)₄Pc, as a potential strategy for enhancing membrane properties. Using Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT), we analyzed the optimized geometries, electronic structures, UV–Vis absorption spectra, FT-IR vibrational spectra, and molecular electrostatic potentials of MPD, Zn(SO₂⁻)₄Pc, and their complexes. The results show that MPD/Zn(SO₂⁻)₄Pc exhibits reduced HOMO-LUMO energy gaps and enhanced charge delocalization, particularly in aqueous environments, indicating improved stability and reactivity. Spectroscopic features confirmed strong interactions via hydrogen bonding and π–π stacking, suggesting that Zn(SO₂⁻)₄Pc can act as a co-monomer or additive during IPol to improve polyamide membrane functionality. A conformational analysis of MPD/Zn(SO₂⁻)₄Pc was conducted using density functional theory (DFT) to evaluate the impact of dihedral rotation on molecular stability. The 120° conformation was identified as the most stable, due to favorable π–π interactions and intramolecular hydrogen bonding. These findings offer computational evidence for the design of high-performance membranes with enhanced antifouling, selectivity, and structural integrity for sustainable water treatment applications. Full article

Hydrogen, as the smallest atom and a key component of water, can penetrate minerals in various forms (e.g., atoms, molecules), significantly influencing their properties. The hydrogen diffusion behavior in corundum (α-Al₂O₃) under high pressure was systematically investigated using the DFT + NEB method. The results indicate that H atoms tend to aggregate into H₂ molecules within corundum under both ambient and high-pressure conditions. However, hydrogen predominantly migrates in its atomic form (H) under both low- and high-pressure environments. The energy barriers for H and H₂ diffusion increase with pressure, and hydrogen diffusion weakens the chemical bonds nearby. Using the Arrhenius equation, we calculated the diffusion coefficient of H in corundum, which increases with temperature but decreases with pressure. On geological time scales, hydrogen diffusion is relatively slow, potentially resulting in a heterogeneous distribution of water in the lower mantle. These findings provide novel insights into hydrogen diffusion mechanisms in corundum under extreme conditions, with significant implications for hydrogen behavior in mantle minerals at high pressures. Full article

Cold environments challenge the structural and functional integrity of membrane proteins, requiring specialized adaptations to maintain activity under low thermal energy. Here, we investigate the molecular basis of cold tolerance in the peptide transporter PepT1 from the Antarctic icefish (Chionodraco hamatus, ChPepT1) using molecular dynamics simulations, binding free energy calculations (MM/GBSA), and dynamic network analysis. We compare ChPepT1 to its human ortholog (hPepT1), a non-cold-adapted variant, to reveal key features enabling psychrophilic function. Our simulations show that ChPepT1 displays enhanced global flexibility, particularly in domains adjacent to the substrate-binding site and the C-terminal domain (CTD). While hPepT1 loses substrate binding affinity as temperature increases, ChPepT1 maintains stable peptide interactions across a broad thermal range. This thermodynamic buffering results from temperature-sensitive rearrangement of hydrogen bond networks and more dynamic lipid interactions. Importantly, we identify a temperature-responsive segment (TRS, residues 660–670) within the proximal CTD that undergoes an α-helix to coil transition, modulating long-range coupling with transmembrane helices. Dynamic cross-correlation analyses further suggest that ChPepT1, unlike hPepT1, reorganizes its interdomain communication in response to temperature shifts. Our findings suggest that cold tolerance in ChPepT1 arises from a combination of structural flexibility, resilient substrate binding, and temperature-sensitive interdomain dynamics. These results provide new mechanistic insight into thermal adaptation in membrane transporters and offer a framework for engineering proteins with enhanced functionality in extreme environments. Full article

The increasing presence of ECs in aquatic environments has drawn significant attention to the need for innovative, accessible, and sustainable solutions in wastewater treatment. This review provides a comprehensive overview of the use of agricultural residues—often discarded and undervalued—as raw materials for the development of efficient bioadsorbents. Based on a wide range of recent studies, this work presents various types of materials, such as rice husks, sugarcane bagasse, and açaí seeds, that can be transformed through thermal and chemical treatments into advanced bioadsorbents capable of removing pharmaceuticals, pesticides, dyes, and in some cases, even addressing highly persistent pollutants such as PFASs. The main objectives of this review are to (1) assess agricultural-residue-derived bioadsorbents for the removal of ECs; (2) examine physical and chemical modification techniques that enhance adsorption performance; (3) evaluate their scalability and applicability in real-world treatment systems. The review also highlights key adsorption mechanisms—such as π–π interactions, hydrogen bonding, and ion exchange—alongside the influence of parameters like pH and ionic strength. The review also explores the kinetic, isothermal, and thermodynamic aspects of the adsorption processes, highlighting both the efficiency and reusability potential of these materials. This work uniquely integrates microwave-assisted pyrolysis, magnetic functionalization, and hybrid systems, offering a roadmap for sustainable water remediation. Finally, comparative performance analyses, applications using real wastewater, regeneration strategies, and the integration of these bioadsorbents into continuous treatment systems are presented, reinforcing their promising role in advancing sustainable water remediation technologies. Full article

Given the adverse effects of organic dyes from aqueous solutions on human physiology and the ecological system, establishing an effective system for their elimination is imperative. This study employs the in situ thermal (IST) method to synthesize nanocomposites comprising zeolitic imidazole frameworks, specifically Fe-ZIF-8 and Fe-ZIF-67. The investigation offers a comprehensive evaluation of the properties of these nano-adsorbents for the removal of malachite green (MG). The results indicate a significantly increased adsorption capacity of up to 495 and 552 mg g⁻¹ for Fe-ZIF-8 and Fe-ZIF-67, respectively. Furthermore, they demonstrate removal efficiencies of up to 90% and 95% for MG, respectively. Parameters associated with the adsorption process are derived from isotherms and removal kinetics, specifically the Freundlich model and the pseudo-second-order kinetics model, respectively. The enhanced adsorption capacity observed in Fe-ZIF-8 and Fe-ZIF-67 can be attributed to π–π stacking interactions, hydrogen bonding, and electrostatic attraction. After undergoing three cycles, both adsorbents consistently exhibit a high removal efficiency of approximately 85%, indicating notable structural integrity and outstanding potential for repeated use. The examined adsorbents display exceptional efficacy, favorable stability, and substantial specific surface area, underscoring their remarkable adsorption capabilities. The nanocomposites comprising Fe-ZIF-8 and Fe-ZIF-67 demonstrate considerable potential as highly favorable options for the elimination of MG and other cationic organic dyes from aqueous environments. Full article

Studies have been conducted on the potential development of Hydrogenobacter thermophilus and Pseudomonas aeruginosa in an anaerobic environment, both in the presence and absence of molecular hydrogen (H₂). H. thermophilus developed better at 70 °C and pH 7.0 in the presence of molecular hydrogen. It also multiplied in its absence, but to a lesser extent. Dissolved hydrogen in an amount of 1 ppm is biologically active for this thermophilic chemolithotrophic species. The tested strains of P. aeruginosa also showed growth under anaerobic conditions in the presence of H₂ concentrations of 1 ppm and 2 ppm, which was ensured by adding Mg. The results indicate that not only the oldest microorganisms on our planet, archaebacteria, but also current species such as H. thermophilus and P. aeruginosa are capable of development under conditions characteristic of the ancient hydrosphere. DFT analyses showed that hydrogen water forms stable water clusters, whose hydrogen bond network retains and stabilizes reducing agents such as molecular hydrogen and magnesium (Mg⁰). This creates a microenvironment in which key redox processes associated with autotrophic growth and chemical evolution can occur. This is a realistic model of the Earth’s primordial hydrosphere’s conditions. Full article

Water within coal reservoirs exerts dual effects on methane adsorption–desorption by competing for adsorption sites and reducing permeability. The bound water effect, caused by coal wettability, significantly constrains coalbed methane (CBM) production, rendering investigations into coal wettability crucial for efficient CBM development. Compared with other geological formations, coals are characterized by a highly developed microporous structure, making the CO₂ sequestration mechanism in coal seams closely linked to the microscale interactions among gas, water, and coal matrixes. However, the intrinsic mechanisms remain poorly understood. In this study, molecular dynamics simulations are employed to investigate the wettability behaviors of CO₂, CH₄, and water on different coal matrix surfaces under varying temperature and pressure conditions, for coal macromolecules representative of four coal ranks. The study reveals the evolution of water wettability in response to CO₂ and CH₄ injection, identifies wettability differences among coal ranks, and analyzes the microscopic mechanisms governing wettability. The results show the following: (1) The contact angle increases with gas pressure, and the variation in wettability is more pronounced in CO₂ environments than in CH₄. As pressure increases, the number of hydrogen bonds decreases, while the peak gas density of CH₄ and CO₂ increases, leading to larger contact angles. (2) Simulations under different temperatures for the four coal ranks indicate that temperature has minimal influence on low-rank Hegu coal, whereas for higher-rank coals, gas adsorption on the coal surface increases, resulting in reduced wettability. Interfacial tension analysis further suggests that higher temperatures reduce water surface tension, cause dispersion of water molecules, and consequently improve wettability. Understanding the wettability variations among different coal ranks under variable pressure–temperature conditions provides a fundamental model and theoretical basis for investigating deep coal seam gas–water interactions and CO₂ geological sequestration mechanisms. These findings have significant implications for the advancement of CO₂-ECBM technology. Full article

The fast-disintegrating capsules rapidly disintegrate in various physiological environments, ensuring therapeutic efficacy. The formulation of plant-based capsules with balanced mechanical and fast disintegration characteristics continues to present technical challenges in pharmaceutical development. In this study, natural marine polysaccharides were utilized to achieve both rapid disintegration and excellent mechanical properties by combining κ-Carrageenan (κ-C) and ι-Carrageenan (ι-C). Additionally, the selection of KCl + NaCl mixed coagulants, along with the evaluation of their types, mass fractions, and ratios, enhanced the mechanical properties and transmittance of the capsules. FTIR analysis revealed that the membrane with a 5:5 κ-C/ι-C ratio formed hydrogen bonds, which were beneficial to its fast disintegration. SEM analysis revealed a dense microstructure in this formulation, contributing to its improved mechanical properties. Finally, this study hypothesizes that the disintegration behaviors of the capsules exhibited significant pH dependence, with ion exudation predominating in pH 1.2 and pH 7.0 media, while swelling dominated under pH 4.5 and pH 6.8 media. The prepared carrageenan blend-based capsules exhibited fast disintegration properties while maintaining excellent mechanical and barrier properties, thereby broadening the application of plant-based capsules in the field of medicine. Full article

Hydrogel sensors show unique advantages in underwater detection, ocean monitoring, and human–computer interaction because of their excellent flexibility, biocompatibility, high sensitivity, and environmental adaptability. However, due to the water environment, hydrogels will dissolve to a certain extent, resulting in insufficient mechanical strength, poor long-term stability, and signal interference. In this paper, a double-network structure was constructed by polyvinyl alcohol (PVA) and poly([2-(methacryloyloxy) ethyl]7 dimethyl-(3-sulfopropyl) ammonium hydroxide) (PSBMA). The resultant PVA/PSBMA-PA hydrogel demonstrated notable swelling resistance, a property attributable to the incorporation of non-covalent interactions (electrostatic interactions and hydrogen bonding) through the addition of phytic acid (PA). The hydrogel exhibited high stretchability (maximum tensile strength up to 304 kPa), high conductivity (5.8 mS/cm), and anti-swelling (only 1.8% swelling occurred after 14 days of immersion in artificial seawater). Assembled as a sensor, it exhibited high strain sensitivity (0.77), a low detection limit (1%), and stable electrical properties after multiple tensile cycles. The utilization of PVA/PSBMA-PA hydrogel as a wearable sensor shows promise for detecting human joint movements, including those of the fingers, wrists, elbows, and knees. Due to the excellent resistance to swelling, the PVA/PSBMA-PA-based sensors are also suitable for underwater applications, enabling the detection of underwater mannequin motion. This study proposes an uncomplicated and pragmatic methodology for producing hydrogel sensors suitable for use within subaquatic environments, thereby concomitantly broadening the scope of applications for wearable electronic devices. Full article

Ferulic acid (FA) exhibits beneficial properties in ulcerative colitis (UC) pathogenesis, while sensitivity to the environment and enzymes limits its use in UC therapy. Therefore, this study aims to develop a colon-targeted nanocomplex delivery system using FA and investigate its protective effects and underlying regulatory mechanisms in UC mice. A novel Zein/FA–pectin (PEC)/chitosan (CS) nanocomplex was successfully fabricated in this study. Through systematic adjustment of the PEC/CS-to-Zein/FA ratio, optimal encapsulation efficiency (60.1%) and loading capacity (26.2%) were achieved. The characterized data indicated that hydrogen bonds, electrostatic interactions, and hydrophobic forces were the main driving forces maintaining the formation of the nanocomplexes, accompanied by alterations in the secondary structure of Zein. The Zein/FA–PEC/CS nanocomplexes demonstrated excellent thermal/storage particle size stability and exhibited both protective and sustained-release effects of FA during simulated gastrointestinal digestion. Furthermore, the results demonstrated that the nanocomplexes potentially alleviate UC by regulating inflammatory cytokines, oxidative stress, and gut microbiota. Compared to unencapsulated FA, the nanocomplexes have a better effect on alleviating UC symptoms. In summary, Zein/FA–PEC/CS nanocomplexes have promising prospects in alleviating colitis in UC mice. Full article

This research represents the first application of the MOLS method to characterize the conformational energy landscape of an antimicrobial peptide within a solvent environment, providing a novel approach to understanding peptide behavior in solution. This method’s exhaustive nature ensures that all minimum-energy conformations for a given amino acid sequence are sampled. In this work, we employed a combination of MOLS and VMD software to generate structural models of a cyclic peptide, both solvated and non-solvated, and then utilized the CHARMM force field to conduct energy calculations throughout the sampling process. In the presence of a solvent, this method predicted a structure close to the experimental crystal structure. A significant reduction was observed in gamma turn motifs in the presence of water. The solvent molecules also favored different hydrogen bonding patterns in the peptide by orchestrating an intermolecular interaction with the peptide atoms. This intermolecular interaction involves an ARG side chain and further stabilizes the backbone. It is evident that solvent interactions are key in designing antimicrobial peptides. This study will help in designing and understanding peptides for use as therapeutic agents like antibacterial or antimicrobial peptides. Each conformer obtained from the MOLS method would be one of the best starting points for molecular dynamic simulation to further explore the landscape. Full article

The persistent contamination of aquatic environments by heavy metals, particularly Pb²⁺, Cd²⁺, and Cu^2+, poses a serious global threat due to their toxicity, persistence, and bioaccumulative behavior. In response, low-cost and eco-friendly adsorbents are being explored, among which CaCO₃-based biocomposites derived from mollusk shells have shown exceptional performance. In this study, a hybrid biocomposite composed of poly(vinyl alcohol) (PVA) and oyster shell-derived CaCO₃ was computationally investigated using Density Functional Theory (DFT) to elucidate the electronic and structural basis for its high metal-removal efficiency. Calculations were performed at the B3LYP/6-311++G(d,p), M05-2X/6-311+G(d,p), and M06-2X/6-311++G(d,p) levels using GAUSSIAN 16. Among them, B3LYP was identified as the most balanced in terms of accuracy and computational cost. The hybridization with CaCO₃ reduced the HOMO-LUMO gap by 20% and doubled the dipole moment (7.65 Debye), increasing the composite’s polarity and reactivity. Upon chelation with metal ions, the gap further dropped to as low as 0.029 eV (Cd²⁺), while the dipole moment rose to 17.06 Debye (Pb²⁺), signaling enhanced charge separation and stronger electrostatic interactions. Electrostatic potential maps revealed high nucleophilicity at carbonate oxygens and reinforced electrophilic fields around the hydrated metal centers, correlating with the affinity trend Cu²⁺ > Cd²⁺ > Pb²⁺. Fukui function analysis indicated a redistribution of reactive sites, with carbonate oxygens acting as ambiphilic centers suitable for multidentate coordination. Natural Bond Orbital (NBO) analysis confirmed the presence of highly nucleophilic lone pairs and weakened bonding orbitals, enabling flexible adsorption dynamics. Furthermore, NCI/RDG analysis highlighted attractive noncovalent interactions with Cu²⁺ and Pb²⁺, while FT-IR simulations demonstrated the formation of hydrogen bonding (O–H···O=C) and Ca²⁺···O coordination bridges between phases. Full article

Tetracycline (TC) is widely used in medicine and livestock farming. TC is difficult to degrade and tends to persist and accumulate in aquatic environments, and it has gradually become an emerging pollutant. Biochar (BC) has strong potential for removing TC from water. This potential arises from its excellent surface properties, low-cost raw materials, and renewable nature. However, raw biomass materials are highly diverse, and their preparation conditions vary significantly. Modification methods differ in specificity and the application scenarios are complex. These factors collectively cause unstable TC removal efficiency by biochar. The chemical activation process using KOH/H₃PO₄ significantly enhanced porosity and surface functionality, transforming raw biochar into an activated carbon material with targeted adsorption capacity. Adjusting the application dosage and environmental factors (particularly pH) further enhanced the removal performance. Solution pH critically governs the adsorption efficiency: optimal conditions (pH 5–7) increased removal by 35–40% through strengthened electrostatic attraction, whereas acidic/alkaline extremes disrupted ionizable functional groups. The dominant adsorption mechanisms of biochar involved π–π interactions, pore filling, hydrophobic interactions, hydrogen bonding, electrostatic interactions, and surface complexation. In addition, the main challenges currently hindering the large-scale application of biochar for the removal of TC from water are highlighted: (i) secondary pollution risks of biochar application from heavy metals, persistent free radicals, and toxic organic leaching; (ii) economic–environmental conflicts due to high preparation/modification costs; and (iii) performance gaps between laboratory studies and real water applications. Full article

Infectious wounds pose formidable clinical challenges due to hypoxia, exacerbated inflammation, and persistent microbial colonization. To address this, we developed a bioinspired multifunctional hydrogel (PTDPs) through the in situ freeze-thaw co-assembly of polyvinyl alcohol (PVA), tea polyphenols (TP), polydopamine (PDA), and marine-derived self-assembling peptides (AAPs). The resultant PTDP hydrogel formed an intricate hydrogen-bonded network that enhanced mechanical robustness and substrate adhesion. TP and PDA synergistically confer potent antioxidant properties: TP scavenges radicals via phenolic hydroxyl groups while PDA enhances responsiveness to diverse radicals in hypoxic environments. Integrated with AAPs’ pro-regenerative functions and PDA’s broad-spectrum antimicrobial efficacy, this system generates therapeutic synergy. Characterization revealed outstanding physicochemical properties including tunable plasticity, high swelling ratios, and sustained hydration retention. In vitro studies demonstrated potent antioxidant activity, efficient inhibition of Staphylococcus aureus and Escherichia coli proliferation, and cytocompatibility facilitating endothelial cell migration/proliferation. In murine full-thickness infected wound models, the PTDP hydrogel significantly accelerated wound closure, enhanced neovascularization, and improved collagen deposition, underscoring its potential as an innovative therapeutic platform for infected and chronic wounds with strong translational prospects. Full article

Proteins are inherently dynamic entities that rely on flexibility across multiple timescales to perform their biological functions. The surrounding environment plays a critical role in modulating protein dynamics by exerting plasticizing or stabilizing effects. In order to characterize the conformational dynamics of Water-Soluble Chlorophyll-Binding Protein (WSCP), we measured Quasielastic Neutron Scattering (QENS) spectra over a wide temperature range between 100 and 300 K. The impact of glycerol, a common stabilizer, is investigated by comparing WSCP dissolved in a glycerol–water-containing buffer (WSCP^W+G) with WSCP in a water-containing buffer (WSCP^W). The results indicate that conformational protein dynamics are widely suppressed below 200 K but increase above this threshold, with the appearance of localized protein motions on the picosecond timescale. Glycerol appears to limit protein mobility between 280 and 300 K due to its high viscosity and hydrogen bonding in contrast to WSCP in water. Inelastic Neutron Scattering (INS) reveals the vibrational dynamics of WSCP with pronounced low-energy protein vibrations observed at about 2.5 and 6 meV. In the presence of glycerol, however, a stiffening of the vibrational motions which shifts the vibrational peaks to higher frequencies is observed. Full article