Search Results (3,349)

To address the clinical urgency of simultaneously monitoring multiple biomarkers in chronic wound infections, this study presents the innovative development of an electrochemical sensor based on a MWCNTs/MXene/PVA composite hydrogel. A dual-channel conductive network is constructed via the electrostatic self-assembly of the two-dimensional material MXene and multi-walled carbon nanotubes (MWCNTs). This strategy not only enhances the charge transfer efficiency but also effectively suppresses the aggregation of MWCNTs and exposes the electrocatalytic active sites. Additionally, the thermal annealing process is incorporated to facilitate the ordered arrangement of polyvinyl alcohol (PVA) nanocrystalline domains, strengthening the hydrogen bond-mediated interfacial adhesion and resolving the issues of hydrogel swelling and delamination. The detection limit (LOD) of the optimized sensor (MWCNTs_0.6/MXene_0.4/PVA) for pyocyanin (PCN) within complex biological matrices, including phosphate-buffered saline (PBS), Luria–Bertani (LB) broth, and saliva, was decreased to a range of 0.84~0.98 μM. Leveraging the disparities in the characteristic oxidation potentials (ΔE > 0.3 V) of PCN, uric acid (UA), and histamine (HA) in simulated wound exudate (SWE), the multi-component synchronous detection functionality of the non-specific sensor was expanded for the first time. This study offers a high-precision and multi-parameter integrated approach for point-of-care testing (POCT) of wound infections. Full article

Sabkhas, hypersaline ecosystems along Kuwait’s coastal zone, are extreme environments that harbor diverse halophilic microorganisms with significant biotechnological potential. Despite this, they remain underexplored, particularly in the context of enzymes that can function under high salinity. The aim of this study is to identify bacterial isolates from Kuwait’s sabkhas that produce α-amylase under extreme environmental conditions and to purify and characterize the resulting halotolerant α-amylase. Among the seven α-amylase-producing isolates, Priestia sp. W243, isolated from Mina Abdullah, exhibited the highest enzyme production under optimal growth conditions of pH 9.0, 37 °C, and 7.5% NaCl. A novel halotolerant α-amylase with a remarkably high specific activity (8112.1 U/mg) was purified from this isolate using ultrafiltration, ion-exchange chromatography, and gel-filtration. The purified enzyme, with a molecular weight of 25 kDa, showed optimal activity at 40 °C, pH 8, and 3% NaCl. Notably, the enzyme remained active in the absence of salt and up to 15% NaCl, demonstrating exceptional halotolerance. Metal ion profiling revealed that enzyme activity was significantly enhanced by Co²⁺, whereas Ca²⁺ had a comparatively moderate effect on enzyme activity. When the effects of metal chelators were examined, EDTA, a strong metal chelator, inhibited the enzyme. However, the enzyme remained active when Ca²⁺ was specifically removed using EGTA, suggesting that this α-amylase may be a cobalt-dependent metalloenzyme, which is an unusual characteristic among known α-amylases. Additionally, the enzyme retained its catalytic activity under reducing conditions (e.g., in the presence of DTT and β-mercaptoethanol), indicating structural stability is independent of disulfide bonds. These unique properties distinguish this α-amylase from typical salt- or calcium-dependent counterparts and highlight its potential for industrial applications in high-salt food processing, baking, brewing, and environmental remediation. Full article

Hydrophobic bioactive compounds such as lutein exhibit poor water solubility and are prone to degradation. Liposomal delivery systems can enhance the solubility and physicochemical stability of lutein (LUT). Liposomes are primarily composed of phospholipids and cholesterol. Since phytosterol ester can reduce cholesterol levels and improve the performance of liposomes, this study used phytosterol oleate ester (POE) as a cholesterol substitute in the preparation of liposomes for delivering LUT (LUT-P-Lip). The physicochemical properties, microstructure, storage stability, antioxidant characteristics, and intermolecular interactions of the liposomes at different LUT concentrations were investigated. The results demonstrated that LUT-P-Lip had a size range of 50–100 nm, with intact morphology and uniform distribution. In vitro studies showed that LUT-P-Lip significantly enhanced the storage stability and antioxidant activity of LUT. The analysis of intermolecular interactions revealed that the enhanced stability was mediated by an increased number of hydrogen bonds and modulation of membrane fluidity. In conclusion, replacing cholesterol with POE during liposome formation enhances both the stability and antioxidant activity of the resulting liposomes. Full article

Seasonal freeze–thaw cycles profoundly alter soil physical properties in cold-region agroecosystems, yet their effects on the mechanical behavior of the ice–soil interface remain poorly quantified. This interface plays a critical role in governing soil structural stability, detachment resistance, and subsequent erosion processes during thaw periods, particularly in the black soil region of Northeast China. In this study, controlled laboratory experiments were conducted to investigate the evolution of ice–soil interface mechanical properties under varying freeze–thaw conditions using cultivated black soils. Key parameters, including interface shear strength and bonding characteristics, were quantified across different freeze–thaw cycles. The results demonstrate that freeze–thaw action significantly weakens the mechanical integrity of the ice–soil interface, with pronounced reductions in shear strength observed after repeated cycles. This degradation is attributed to ice lens formation, pore structure disruption, and the redistribution of interfacial water films during freezing and thawing. Notably, the rate and magnitude of strength loss exhibit strong sensitivity to freeze–thaw frequency, highlighting the cumulative nature of freeze-induced damage at the interface scale. These findings provide mechanistic insights into how freeze–thaw processes modulate soil resistance to external forces during early thaw periods, offering an improved physical basis for understanding soil erosion vulnerability in cold agricultural regions. The results have direct implications for soil conservation strategies and erosion modeling under ongoing climate warming, which is expected to intensify freeze–thaw dynamics in seasonally frozen farmlands. Full article

To obtain data on the effects of ozonolysis on the structural and dynamic parameters of ultrafine fibers based on the binary compositions of poly-(3-hydroxybutyrate) (PHB) and polyvinylpyrrolidone (PVP) with varying ratios of polymer components ranging from 0/100 to 100/0 mass%, produced by electrospinning, a study was conducted. The morphology and structural–dynamic characteristics of the ultrafine fibers were examined. Comprehensive research was carried out, combining thermophysical measurements (DSC), dynamic measurements using an electron paramagnetic resonance (EPR) technique, scanning electron microscopy, and infrared spectroscopy. The influence of the mixture’s composition and ozonolysis on the degree of crystallinity of PHB and the molecular mobility of the TEMPO radical (tetramethylpiperidine-1-oxyl) in the amorphous regions of the PHB/PVP fiber material was demonstrated. The low-temperature maximum on the DSC thermograms provided information about the fraction of hydrogen bonds in the mixed compositions, allowing for the enthalpy of thermal destruction of these bonds in both the original and oxidized samples to be determined. The study showed significant changes in the degree of crystallinity of PHB, the enthalpy of hydrogen bond destruction, molecular mobility, moisture absorption of the compositions, and the activation energy of rotational diffusion in the amorphous regions of the PHB/PVP mixed compositions. It was established that within the 50/50% PHB/PVP ratio, an inversion transition occurs from the dispersion material to the dispersion medium. Ozonolysis induces a sharp change in the material’s structure. The conducted research provided the first opportunity to assess the impact of ozonolysis on the structural and dynamic characteristics of PHB/PVP ultrafine fibers at a molecular level. These materials may serve as a therapeutic system for controlled drug delivery. Full article

Electronic and spin structures of open-shell molecules and clusters were investigated as possible building blocks for the construction of one- and two-dimensional quantum spin alignment systems which exhibited several characteristic quantum properties of strongly correlated electron systems: high-T_c superconductivity, quantum spin coherence, entanglement, etc. Ab initio calculations were performed to elucidate effective exchange integrals (J) for 3d transition metal oxides, providing the J-model for high-T_c superconductivity. Theoretical investigations such as Monte Carlo simulation, molecular mechanics and quantum mechanical calculations were performed to elucidate effective chemical procedures for through-bond alignments of open-shell transition metal ions by organometallic conjugation and through-space confinements of molecular spins such as molecular oxygen by molecular confinement materials. Theoretical simulations have elucidated the importance of appropriate confinement materials for alignments of molecular spins desired for quantum coherence and quantum sensing. Equivalent transformations among coherent states of superconductors, trapped ion, neutral atom, molecular spin, molecular exciton, etc., are also discussed on theoretical and conceptual grounds such as quantum entanglement and decoherence. Full article

This work aims to enhance the stability of the Mg/Al₃Y interface through first-principles investigations of low-cost dopants. Density functional theory calculations were employed to systematically examine the bulk properties of Mg and Al₃Y, as well as the structural stability, electronic characteristics, and alloying element effects at the Mg(0001)/Al₃Y(0001) interface. The calculated lattice parameters, elastic moduli, and phonon spectra demonstrate that both Mg and Al₃Y are dynamically stable. Owing to the similar hexagonal symmetry and a small lattice mismatch (~1.27%), a low-strain semi-coherent Mg(0001)/(2 × 2)Al₃Y(0001) interface can be constructed. Three representative interfacial stacking configurations (OT, MT, and HCP) were examined, among which the MT configuration exhibits significantly higher work of adhesion, indicating superior interfacial stability. Differential charge density and density of states analyses reveal pronounced charge transfer from Mg to Al/Y atoms and strong orbital hybridization, particularly involving Y-d states, which underpins the enhanced interfacial bonding. Furthermore, the segregation behavior and adhesion enhancement effects of typical alloying elements (Si, Ca, Ti, Mn, Cu, Zn, Zr, and Sn) were systematically evaluated. The results show that Mg-side interfacial sites, especially Mg₂ and Mg₃, are thermodynamically favored for segregation, with Zr and Ti exhibiting the strongest segregation tendency and the most significant improvement in interfacial adhesion. These findings provide fundamental insights into interfacial strengthening mechanisms and offer guidance for the alloy design of high-performance Mg-based composites. Full article

The interaction between small organic molecules and coal macerals plays a critical role in regulating fluid retention and transport in coal-related energy and environmental systems. However, the microscopic mechanisms governing adsorption selectivity and interfacial dynamics on different maceral surfaces remain insufficiently understood. In this study, molecular dynamics simulations were employed to investigate the adsorption and desorption behaviors of toluene (TOL) and tetrahydrofuran-2-ol (FUR) on inertinite (INE) and vitrinite (VIT) surfaces at the molecular level. Time-dependent variations in adsorption number, residence time, molecular mobility, interaction energies, and hydrogen-bond characteristics were systematically analyzed. The results reveal strong maceral- and molecule-dependent adsorption preferences. TOL exhibits the most stable adsorption on the INE surface, characterized by rapid surface accumulation, minimal desorption, and a long residence time of 0.43547 ns, which is mainly driven by strong van der Waals interactions and aromatic stacking effects. In contrast, TOL adsorption on VIT is highly dynamic, with frequent desorption events and a markedly reduced residence time of 0.1077 ns. FUR shows relatively weaker and more reversible adsorption on INE, accompanied by enhanced molecular mobility and a shorter residence time of 0.31354 ns. Notably, FUR demonstrates stronger surface retention on VIT, with an extended residence time of 0.34439 ns, which can be attributed to increased electrostatic contributions and intermittent hydrogen bonding. Hydrogen-bond analysis indicates that FUR forms longer-lived hydrogen bonds with VIT (22.05 ps) than with INE (17.86 ps), providing additional stabilization at the interface. These findings elucidate the distinct adsorption mechanisms of aromatic and polar molecules on heterogeneous coal macerals and offer molecular-scale insights into organic matter–coal interfacial processes relevant to energy extraction and subsurface transport. Full article

Optimizing stirring methods is crucial for enhancing the efficiency of the Electric Arc Furnace (EAF) production process. This study explores the mixing characteristics of a 150-ton Consteel EAF. The similarity ratio between the water model and the prototype is 1:8. The average mixing time (AMT) was employed as the criterion to evaluate various stirring methods, including the horizontal deflection angle of side-blowing, non-uniform bottom-blowing layouts, and their combinations. A new ice whose composition was a 35 wt% sugar solution was used to simulate the movement and bonding of scrap steel. The melting and temperature difference were compared in this way. The conclusions are as follows: (1) The side blowing lances with a certain angle of horizontal deflection are more conducive to the mixing of the molten pool. The preferred side-blowing lances’ horizontal deflection angle is 10°. (2) The preferred bottom blowing layout is EKO. The bottom blowing layout needs to pay attention to the offset between the bottom blowing nozzles. Bottom blowing nozzles cannot be too far or too close. Rational non-uniform layout of bottom blowing is better than uniform. (3) The preferred combined stirring layout is the EKN, combined with side blowing, with counterclockwise deflection of 10° in the horizontal direction. Gas injection of side blowing and bottom blowing exhibits complementary action zones, thereby achieving enhanced stirring uniformity in the molten bath. But it is necessary to consider the bottom-blowing and side-blowing positions to avoid the local kinetic energy loss caused by airflow offset. At the same time, the deflection angle of the side-blowing lances should be consistent with the direction of the circulation formed by the non-uniform bottom blowing. (4) Under the rational combined stirring method, the scrap steel moved faster, and the bonding phenomenon was significantly reduced. And the temperature difference decreased the fastest. In summary, the rational combined stirring method is the most preferred method for mixing. Full article

This study investigates the flexural behavior and practical application of Reinforced Concrete (RC) beams strengthened with Ultra-High Performance Concrete (UHPC). Flexural tests were conducted on ten beam specimens to systematically analyze the effects of steel fiber dosage, reinforcement ratio, and beam height on the failure modes, load-bearing capacity, and deformation characteristics of the strengthened beams. The results were compared with those of unstrengthened control beams (CB). Experimental observations indicated excellent interfacial bonding between the UHPC layer and the RC beam, with no debonding failure occurred. All specimens exhibited typical under-reinforced flexural failure characteristics, and their load–deformation curves displayed three distinct stages. Compared to the control beams, the ultimate load-bearing capacities of the strengthened beams increased by 9.5–15.7% with varying steel fiber dosages, 16.4–110.2% with varying reinforcement ratios, and 6.2–518.8% with varying beam heights. Furthermore, the UHPC layer significantly enhanced the flexural stiffness of the beams. Although ductility was slightly reduced, all strengthened beams demonstrated clear yield characteristics prior to failure, avoiding brittle fracture. Additionally, nonlinear numerical simulations performed using MATLAB R2020a showed high agreement with the experimental results, verifying the accuracy of the analytical procedure. Based on the validated model, a parametric study was conducted to further investigate the influence of beam height, reinforcement ratio, and interface coefficients on flexural performance. The findings confirm the reliability and effectiveness of the UHPC strengthening technique. Full article

Cellulose nanofiber (CNF) has attracted increasing attention as a sustainable nanomaterial for high-performance films due to its renewability and outstanding mechanical properties. However, the practical applications of CNF films are largely hindered by their insufficient tensile flexibility and gas barrier performance. In the present work, a reinforced, multifunctional nanocomposite film was prepared via the solution casting method by incorporating CNF with poly(butylene adipate-co-terephthalate) (PBAT). The influence of PBAT loading on the mechanical flexibility and barrier performance of the nanocomposite film was investigated, and the interfacial bonding characteristics were also studied. As a result, the composite film containing 40 wt% PBAT (denoted as CNF-PBAT40) exhibited a tensile strength of 49.6 MPa, which is generally seven times higher than that of the pristine CNF film. Moreover, its flexibility was notably enhanced, reaching an elongation at break of 7.8%. Additionally, the CNF-PBAT40 composite film showed a markedly reduced air permeability of 2.6 μm·Pa⁻¹·s⁻¹, compared with 9.5 μm·Pa⁻¹·s⁻¹ for the pristine CNF film. Therefore, these synergistically enhanced properties render CNF-PBAT composite films promising candidates for advanced applications in next-generation sustainable packaging. Full article

In response to the challenge of achieving highly reliable interface fabrication in the fields of microelectronics and micro-electromechanical system (MEMS) packaging, this study harnesses the superior characteristics of solid-state bonding inherent in explosive welding (EXW) technology. This study investigates the precise EXW of milligram-scale metallic foils by employing focused laser energy to control the explosion behavior of liquid energetic materials, thereby generating shockwaves that induce high-velocity oblique collisions between metallic foils and base plates. Laser-focused energy was utilized to regulate energetic materials for conducting precision EXW experiments on Al/Cu couples. The technical feasibility and interfacial quality of this method for fabricating Al/Cu bonding interfaces were systematically evaluated through in situ observation of the dynamic welding process, comprehensive analysis of interfacial microstructures, and numerical simulations. The results reveal distinct Al/Cu elemental diffusion at the bonding interface, confirming the technical viability of the approach. However, an unloading rebound phenomenon is observed at the interface, which is inherently associated with the dynamic impact process, indicating the need for further optimization in the precise control of impact loading. Full article

As the importance of emotional interaction between humans and robots continues to gain attention, numerous studies have been conducted to identify the characteristics and effects of emotional HRI (Human–Robot Interaction) elements applied to robots. However, no study has yet combined various HRI elements into a single robot and conducted large-scale user experiments to determine which HRI element users prefer the most. This study selected four characteristics that facilitate attachment and emotional bonding between humans and animals: grooming, emotional transfer, imprinting, and cooperative hunting (play). These four characteristics were incorporated into the design and behavioral patterns of the robot EDIE as HRI elements. To allow users to effectively experience these elements, a 30 min runtime robot performance content featuring EDIE as the main character was developed. This large-scale experiment in the form of a performance enabled participants to engage with all four HRI elements and then respond to a survey identifying their most preferred element. Over two experiments involving a total of 3760 participants, this study examined trends in user preferences regarding the robot’s characteristics. By identifying the most effective HRI elements for fostering user attachment to robots, the findings aim to contribute to the harmonious coexistence of humans and robots. Full article

Basalt Fiber Reinforced Polymer (BFRP) bolts offer a high mechanical performance, yet their non-destructive evaluation in anchorage systems remains scarcely investigated. This work examines guided wave propagation in BFRP bolt anchorage structures through a combined experimental and numerical analysis. Optimal excitation within 35–100 kHz was determined experimentally, revealing 40 kHz as the most stable mode, with a pronounced bottom reflection and a peak-to-peak amplitude of 0.31 V. Numerical simulations explored the influence of anchorage medium properties, bolt characteristics, and de-bonding defect locations and lengths on dispersion, attenuation, velocity, radial energy distribution, and echo response. The results indicate that denser anchorage media reduce velocity and attenuation but enhance radial nonuniformity, whereas a higher elastic modulus decreases amplitude and increases attenuation; a larger Poisson’s ratio elevates both velocity and attenuation. For the bolt, a higher density lowers velocity and attenuation, while a greater modulus amplifies both; Poisson’s ratio exerts a minor positive effect. Defect echo time varies linearly with defect position, and increasing the defect length elevates velocity yet diminishes amplitude. These findings elucidate the interplay between material parameters, defect geometry, and guided wave behavior, offering a basis for the optimized non-destructive testing (NDT) of BFRP bolts and facilitating their deployment in engineering applications. Full article

Hydrogels are 3D networks of hydrophilic crosslinked polymers, which are synthesized from synthetic or natural sources such as chitosan and alginic acid derived from shrimp shell and brown seaweed, respectively. These materials exhibit biodegradability, biocompatibility, and non-cytotoxic properties to be used as scaffolds for tissue engineering applications. In this study, four types of alginic acid hydrogels were chemically synthesized using spermidine as a crosslinking agent with concentrations ranging from 5% (w/w) to 100% (w/w). The results of scanning electron microscopy (SEM) revealed a small average pore size (≤5 μm), while electrospray ionization mass spectrometry (ESI-MASS) and Fourier transform infrared spectroscopy (FT-IR) showed the characteristic vibrations and formed bonds between alginic acid and spermidine, respectively. Finally, the alginic acid hydrogels demonstrated potential ability for tissue regeneration treatments. Full article