Search Results (1,084)

An efficient bacteriophage delivery system needs to be developed to overcome the challenges associated with phage instability, rapid diffusion, and loss of infectivity at the infection site. Hydrogels have been found to be potential carriers. Hydrogels have emerged as promising carriers due to their biocompatibility, tunable physicochemical properties and capacity for controlled release. However, the molecular factors that regulate phage–hydrogel interactions remain poorly understood. In this study, we employed an in silico framework combining molecular docking, molecular dynamics (MD) simulations, MM/PBSA binding energy calculations, machine learning-based adhesion prediction, and diffusion modeling to explore phage–hydrogel interactions at the molecular level. Surface-exposed bacteriophage proteins, such as capsid and tail proteins, were evaluated against eight different hydrogel polymers. Binding site analysis revealed the presence of multiple solvent-accessible pockets that can interact with the polymer. Docking studies showed favorable and stable interactions, with hyaluronic acid showing strong binding affinity to multiple phage proteins (−5.5 to −5.7 kcal/mol) and GelMA showing high affinity to the capsid gp10 protein (−5.6 kcal/mol). The integrity of the structural complexes was further confirmed by 100 ns MD simulations, stable RMSD and RMSF trajectories, compact structural conformations, and favorable MM/PBSA binding energies. Machine learning classification successfully differentiated high- and low-adhesion systems and identified hydrogen bonding and electrostatic interactions as key determinants of sustained yet reversible phage retention. Collectively, our findings suggest that the hydrogels enriched with charged and polar functional groups can facilitate stable but non-destructive phage binding, enabling controlled and sustained release. This study provides mechanistic insights into rational hydrogel design for phage delivery systems and highlights the potential of high-throughput computational strategies to accelerate the development of optimized phage therapeutics. Full article

A low-current compact extraction and matching system has been designed and experimentally tested to evaluate its capability for direct proton injection of 15 keV into a 750 MHz radiofrequency quadrupole for medical applications. The design methodology combined 2D and 3D layouts, supported by detailed electrostatic simulations. First experimental results are reported, including beam current characterization and irradiation measurements under varying operating conditions. These results are benchmarked against simulation data to provide a preliminary evaluation of system performance. Ongoing efforts focus on extending the experimental campaign to consolidate these findings. A comparative study with a gridded-lens-based extraction and transport system is also being conducted to achieve reliable matching of high-quality beams to high-frequency RFQs for clinical implementation. Full article

For a protein to perform its biological functions, it must adopt a specific three-dimensional conformation. In addition, many proteins require the assistance of other protein complexes known as chaperonins to fold —i.e., to acquire such a specific conformation—, although the exact mechanisms whereby the chaperonins act and assist the folding process have not been completely determined. In this work, we characterize the physical environment at the interior of the chaperonin HSP60/HSP10 via Molecular Dynamics Simulations. We found that, inside the cavity of the chaperonin (within a region covering much of the cavity’s volume), the long-range electrostatic potential presents a structured pattern that, except for small fluctuations, does not change in time. The electrostatic potential generates an electric field that can be modeled, as a first approximation, as constant and unidirectional $(\mathit{E}/\left(\mathrm{V}·{\AA }^{-1}\right)\approx -0.0054\widehat{𝚤}+0.010\widehat{\mathit{𝚥}}-0.162\widehat{k}$, here the chaperonin’s main axis is aligned along $\widehat{k})$, which can produce large deformations in the structure of a heated protein (Rhodanese); the long-range approximated $\mathit{E}\left(\mathit{r}\right)$ can in fact unfold the Rhodanese, when applied as an external field. Finally, we discuss the possible implications of such an electric field for the protein folding problem, within the context of proteins whose folding is assisted by chaperones. The existence and effects of the electric field are consistent with several theories and experimental observations related to the protein folding problem, in particular with the foldon view. Full article

Cyclotides are exceptionally stable plant peptides whose biological activity is widely attributed to interactions with lipid membranes, yet the molecular mechanisms underlying these interactions remain incompletely resolved. Here, we employ microsecond-scale (1 μs) all-atom molecular dynamics simulations to investigate the membrane association of the cyclotide kalata B1 with phospholipid bilayers of distinct headgroup composition, including POPC, POPE, and POPG. This extended timescale enables full bilayer equilibration and allows observation of slower peptide-induced membrane responses that are not accessible in shorter simulations. Across all systems, kalata B1 rapidly adsorbs to the membrane surface and remains predominantly surface-associated throughout the simulations, while the cyclic cystine knot motif remains structurally intact, confirming the exceptional robustness of the cyclotide fold during membrane engagement. Lipid-dependent differences arise primarily from variations in peptide orientation, conformational flexibility, and interfacial dynamics rather than deep bilayer insertion or pore formation. Zwitterionic POPC membranes favor compact, upright peptide configurations, whereas POPE and POPG bilayers promote enhanced lateral spreading and dynamic reorganization driven by hydrogen bonding and electrostatic interactions, respectively. Leaflet-resolved analyses of lipid contacts, membrane thickness, and area per lipid reveal localized, asymmetric perturbations confined to the peptide-exposed leaflet, with no evidence of sustained bilayer thinning or global destabilization. Together, these results support an interfacial, headgroup-dependent mechanism of cyclotide membrane activity and reconcile previous experimental observations. This work provides molecular-level insight into lipid selectivity and early-stage cyclotide–membrane interactions that may inform future design of cyclotide-based bioactive agents. Full article

Managing excessive water production in oil fields during primary, secondary, or enhanced recovery remains challenging. It increases costs and reduces hydrocarbon recovery, particularly in reservoirs with high-conductivity pathways such as high-permeability zones and fractures. Hydrogels are commonly used for water blocking and retention; however, their effectiveness diminishes at higher flow rates due to mechanical weaknesses and structural limitations. These problems are intensified under harsh environmental conditions, including high temperatures, salinity, and hardness. In this study, we investigate how altering the molecular suprastructure of preformed particle gel (PPG) can improve its effectiveness in shear-responsive water-blockage treatments, particularly when traditional PPGs cannot control rising flow rates. We enhance the shear-responsive mechanical properties of a composite PPG by increasing the density and diversity of intermolecular interactions. We use two different strategies: first, incorporating cationic groups into the polymer backbone to form a polyampholyte network with stronger electrostatic interactions; second, adding a linear anionic polymer to generate a secondary interpenetrating network that can undergo a coil–stretch transition under thermal and shear stimuli, thereby enhancing its own solvation and whole-network expansion. Molecular simulations provide an interpretation of the experimentally observed shear-thickening response and enhanced disproportionate permeability reduction at high flow rates. The water residual resistance factor of the improved PPGs deviates from the typical shear-thinning power-law behavior (n < 1) observed in conventional PPG, showing shear-thickening (n > 1). Tests reveal a strong ability to preferentially reduce water flow over oil, with Disproportionate Permeability Reduction increasing from 8 to 117 in the high-flow-rate zone. The enhanced strength and thermal stability also improve resistance to washout under high-pressure gradients. This research provides a novel approach to tailoring the microscopic architecture of PPGs to achieve selective, robust water blockage, offering a high-efficiency solution for complex reservoir environments. Full article

Powder coatings, as a widely used green surface treatment material, face significant combustion and explosion risks due to the simultaneous presence of high-concentration combustible dust clouds and electrostatic ignition sources in their application environments. With the advancement of new materials and emerging industrial sectors, research on powder coating explosions has become increasingly interdisciplinary, resulting in a somewhat fragmented knowledge base. To systematically reveal the knowledge structure, research hotspots, and development trends in this field, this study employs bibliometric methods based on 857 relevant publications retrieved from the Web of Science (WOS) Core Collection database between 2015 and September 2025. Using VOSviewer (Version 1.6.20) and CiteSpace (Version 6.4), the analysis examines institutional collaboration, journal distribution, author collaboration patterns, regional differences, co-citation relationships, knowledge foundations, and research frontiers. The results indicate that powder coating explosion research has gradually developed an integrated knowledge system centered on materials science, chemical engineering, and combustion science. Institutions from China, Russia, and India represent some of the most productive contributors in this field. Current research hotspots focus on the explosion mechanisms of powder coatings, explosion-proof materials, risk assessment, numerical simulation, and protective measures for emerging industrial applications. Future trends are expected to focus increasingly on intelligent explosion suppression systems, multi-scale coupling mechanisms, and international collaborative governance. This study provides a comprehensive knowledge map to support scientific planning and safety strategy development in powder coating explosion research. Full article

The increasing discharge of synthetic dyes into industrial wastewater necessitates sustainable and low-cost treatment strategies. This study valorizes orange seed powder (OSP), an abundant agro-food residue, as a novel biosorbent for Congo red (CR) removal through a combined experimental and molecular simulation approach. Raw OSP was prepared solely by drying and grinding, without chemical activation, emphasizing its practical applicability and environmental sustainability. Physicochemical characterization using FTIR, SEM, and EDX confirmed adsorption-induced structural and compositional changes. Batch experiments evaluated the effects of initial dye concentration, adsorbent dosage, pH, temperature, and contact time. Equilibrium data were well fitted by the Langmuir and Freundlich isotherm models (R² ≈ 0.99), with a maximum adsorption capacity of 258.39 mg g⁻¹ at 25 °C and pH 4, and a removal efficiency exceeding 99.55%. The adsorption kinetics followed a pseudo-second-order model, while intraparticle diffusion contributed to the rate-controlling mechanism, as indicated by the Weber–Morris model. OSP demonstrated excellent regeneration performance over five adsorption–desorption cycles, retaining more than 96% of its initial CR removal efficiency when regenerated with methanol. Grand Canonical Monte Carlo (GCMC) simulations revealed that adsorption is primarily driven by electrostatic interactions, hydrogen bonding, and π–π stacking interactions, in good agreement with the experimental findings. Overall, raw OSP represents an efficient, regenerable, and sustainable biosorbent, highlighting the originality of integrating experimental investigations with GCMC simulations for wastewater treatment applications. Full article

Acinetobacter baumannii (A. baumannii) represents a major threat because of its multidrug resistance, achieved through its ability to control virulence, and its mechanisms of drug efflux resistance. In this study, we used a combined experimental–computational approach to create and evaluate antimicrobial peptides that targeted the two essential pathogenic proteins, BfmR and AbaQ. The genomic analysis of a clinical isolate showed an extensive resistome and virulence profile, which matched high-risk global lineages. This study conducted molecular docking of an experimental AMP (cathelicidin KR-12 screened from the literature) and a rationally designed synthetic AMP (modified KR-12 analog) with pathogenic proteins, followed by 200 ns molecular dynamics simulations to evaluate both the binding stability and inhibitory potential of the compounds. The disk diffusion assay and microdilution assay were performed against A. baumannii. The study used comparative trajectory analyses, including RMSD, RMSF, radius of gyration, solvent-accessible surface area, principal component analysis, and MM-PBSA free energy calculations, to show that the synthetic AMP created stable electrostatic and hydrogen-bond networks, which caused conformational locking, and reached lower energy states than the experimental peptide. The synthetic AMP showed significant inhibition in validation in vitro. Contrastingly, the experimental AMP had transient interactions and no specificity. The study demonstrates that rationally designed AMPs have therapeutic potential, while the results create a reliable in silico framework to combat multidrug-resistant A. baumannii. Full article

Trichothecene mycotoxins, especially T-2 toxin, represent a significant threat to food safety and public health. Although the enzymatic degradation of deoxynivalenol has been extensively investigated, there are few reports of enzymes capable of efficiently degrading T-2 toxin. This study identified that the aldo-keto reductase AKR13B3 from Devosia A6-243 exhibits 3-keto-DON-degrading and a little T-2 toxin-degrading activity. To address this limitation, a rational design strategy targeting the substrate-binding pocket was employed to enhance its activity. Utilizing site-directed and combinatorial mutagenesis, a double mutant R134F/D217A was successfully screened. R134F/D217A retains catalytic activity towards 3-keto-DON while significantly enhancing its catalytic capacity for T-2. Specifically, the R134F/D217A variant exhibited a 2.88-fold increase in catalytic activity and a 3.15-fold enhancement in catalytic efficiency (k_cat/K_m) relative to the wild type enzyme. Notably, a substantial improvement in thermal stability was also observed. After incubation at 55 °C, the residual activity of the R134F/D217A mutant was 2.63 times that of the wild type. Molecular dynamics (MD) simulations and three-dimensional structural modeling suggested the mechanistic basis for the enhanced performance of the R134F/D217A double mutant. Catalytic enhancement stems from a shortened nucleophilic attack distance, a positively biased electrostatic environment, combined with an enlarged pocket and reduced binding free energy. Concurrently, the increased thermal stability results from decreased flexibility and a more rigid structural architecture. This work presents the first report of AKR13B3 as an effective enzyme for T-2 toxin transformation, and its catalytic activity was significantly enhanced through rational design. Thus, a novel enzymatic strategy was proposed, and could inform future approaches to study issues related to T-2 toxin contamination. Full article

In situ cancer vaccines activate antitumor immune responses by locally capturing and presenting tumor-derived antigens, in which polymers play a key role as antigen-capturing materials. However, the influence of polymer composition and degree of polymerization (DP) on antigen capture efficiency and protection mechanisms remains insufficiently understood. In this study, the tumor-specific antigen MAGE-A3, highly expressed in esophageal squamous cell carcinoma (ESCC), was employed to investigate antigen capture and stabilization by five representative polymers—chitosan, polyethyleneimine (PEI), alginate, polycaprolactone (PCL), and poly (lactic-co-glycolic acid) (PLGA)—with different DPs, using molecular dynamics simulations and in vitro experiments. All-atom simulations revealed that hydrophobic interactions dominate polymer–antigen binding, while electrostatic interactions from cationic polymers synergistically enhance binding affinity and capture efficiency. Binding free energy analysis showed that van der Waals and electrostatic contributions stabilize the complexes, whereas polar solvation partially counteracts these effects. Experimentally, low-DP chitosan exhibited the highest antigen-capture efficiency (38.9%), attributed to its small molecular size, enabling multipoint binding across the antigen surface. In contrast, high-DP polymers generated pronounced steric hindrance that suppressed antigen–enzyme interactions and inhibited hydrolysis. These findings clarify how polymer composition and chain length jointly regulate antigen capture and protection, providing mechanistic guidance for the rational design of polymer-based in situ cancer vaccines. Full article

In recent years, microelectromechanical systems (MEMS) filters exploiting structural nonlinearity and coupled resonance have enabled programmable passband shaping beyond traditional single-peak designs, yet they still face low operating frequencies and limited electrical tuning range. Here, leveraging 1:1 internal resonance, we propose a gate-programmable tuning strategy for two-dimensional (2D) material-based nanoelectromechanical systems (NEMS), enabling high-frequency operation and wide-range reconfigurability. Benefiting from the high resonant frequency and wide electrostatic tunability of 2D materials such as MoS₂, our theoretical analysis indicates wide-range programmability up to $f/f_0\approx 200\%$. Sweeping $V_{g1}=V_{g2}$ from 9 to 16 V while maintaining $\approx 1:1$ frequency matching shifts the passband upward quasi-linearly at $4.4~\mathrm{MHz}/\mathrm{V}$. In contrast, with the coupling strength nearly unchanged, mV-level bias mismatch perturbs the frequency ratio by ${10}^{-5}$, enabling highly sensitive bandwidth trimming from 3.18 to 5.20 kHz, supporting a two-step strategy of coarse center-frequency tuning followed by fine bandwidth control. To broaden the bandwidth, we further analyze a three-drum case: with $V_{g1}=V_{g2}=V_{g3}=16 \mathrm{V}$, the bandwidth reaches 21.79 kHz with a 5056.05 dB/MHz transition slope and 0.95 dB ripple, which is nearly 4 times wider than the two drum case with the same gate voltage. This study shows that 1:1 internal resonance can be used to tune the bandpass response of NEMS resonators. All results are obtained from theoretical modeling and numerical simulations. Full article

Rising atmospheric CO₂ levels have increased the demand for robust, scalable adsorbents for practical CO₂ capture and separation. Porous organic polymers (POPs) are attractive candidates because their pore architecture and binding site properties can be precisely tuned via building blocks and linkage formation. This review summarizes experimental and computational studies of azo-linked POPs and, more broadly, nitrogen–nitrogen (N–N) linked systems, emphasizing how synthetic routes, building blocks, and framework topology govern CO₂ uptake. We highlight key synthetic strategies and representative systems, including porphyrin–azo networks, and discuss the relatively sparse experimental literature on alternative N–N linked POPs incorporating azoxy and azodioxy motifs. Emphasis is placed on reversible nitroso/azodioxide chemistry as a potential pathway to ordered porous organic materials. Computational studies provide a practical route to connect structure with adsorption behavior in largely amorphous or partially ordered networks. We review hierarchical workflows combining periodic DFT and electrostatic potential properties, grand canonical Monte Carlo (GCMC) simulations, and binding energy calculations to rationalize trends and identify favorable binding environments. Computational findings demonstrate that pore accessibility and stacking models can strongly influence predicted CO₂ adsorption. This review provides guidelines for designing POPs with enhanced CO₂ adsorption, offering an outlook and discussing challenges for future studies. Full article

This study presents the engineering design and system-level modeling of a high-frequency power supply architecture for electrostatic precipitators intended to improve particulate removal efficiency and operational stability. Atmospheric air pollution by fine particulate matter (PM2.5) remains one of the most critical challenges in environmental protection and public health. Although electrostatic precipitators (ESPs) are widely used for industrial gas cleaning, the efficiency and stability of conventional 50 Hz power supplies are limited under conditions of strongly nonlinear corona discharge and high-resistivity dust. This paper presents the development and investigation of an advanced high-frequency power supply system for electrostatic precipitators based on a coupled electrical–electrophysical mathematical model. The work follows an engineering design methodology that integrates converter topology selection, electrophysical modeling of corona discharge, and control-oriented system optimization. The proposed model provides a unified description of electric field formation, space charge accumulation, ion transport, and particle motion in the corona discharge region. The simulation results show that in the operating voltage range of 10–100 kV, the electric field strength reaches (2–5)·10⁶ V/m, the ion concentration stabilizes in the range of 10¹³–10¹⁵ m⁻³, and the particle drift velocity increases from approximately 0.05 to 0.3 m/s, leading to an increase in collection efficiency from about 55% to 93%. It is demonstrated that the proposed system ensures stable output voltage regulation within ±2.5–5% even under strongly nonlinear load conditions. The use of an LC output filter (C = 1–10 nF, L = 10–100 mH) reduces the voltage ripple from about 14% to 1.4–4.8% and significantly improves the transient response. In addition, adaptive adjustment of the pulse repetition frequency in the range of 10–200 kHz makes it possible to reduce energy consumption by 12–18% while simultaneously increasing the collection efficiency by 8–15%. The obtained results confirm that the proposed high-frequency power supply architecture provides a physically well-founded and energy-efficient solution for improving the environmental performance and operational stability of electrostatic precipitators. Full article

Addressing the insufficient sensitivity of typical Archimedean spiral antennas for detecting partial discharge (PD) in electrical equipment, this paper proposes a high-sensitivity regulation technique for PD Archimedean antennas based on rotating unit-cell reflective metasurfaces. First, a finite element model of the ultra-high-frequency Archimedean antenna was constructed. Then, employing metasurface electromagnetic wave reflection technology and phase compensation principles, a rotating-unit reflective metasurface was designed to optimize its full-bandwidth gain. A multi-parameter joint optimization method was used to obtain the optimal data for the antenna and metasurface parameters. Finally, simulations and experimental analyses of the super-surface-controlled Archimedean antenna revealed the following: The gain of the Archimedean antenna controlled by the rotating-unit super-surface increases by up to 15.61 dB in the 0.3–1.5 GHz band, with an average full-band gain enhancement of 3.42 dB. During electrostatic discharge (ESD), the amplitude of UHF signals detected by the Archimedean antenna increases by approximately 88.9%, and the amplitude detection of UHF signals during GIS discharges increases by approximately 138.6–150%. These results demonstrate that the metasurface significantly enhances the antenna’s gain performance, providing a reference for highly sensitive control technologies in detecting discharges in electrical equipment. Full article

Bacteriophages (phages) offer a targeted biocontrol solution, but their direct application is hampered by environmental instability. To address this, we developed a novel, food-grade microcapsule system for phage delivery using layer-by-layer (LbL) self-assembly of zein and carboxymethyl chitosan (CMCS). Lytic phages targeting specific spoilage bacteria were successfully encapsulated via electrostatic interactions. Characterization confirmed the formation of a multilayer structure, driven primarily by hydrogen bonding and electrostatic forces between the wall materials. The microencapsulation markedly enhanced phage stability against thermal (60 °C and 70 °C) and extreme pH (2.0, 12.0) stresses and provided a controlled release profile in a simulated fish exudate. When applied to fresh-cut sea bass (Lateolabrax japonicus), the phage-loaded microcapsules (CMCS3), constructed via a three-layer zein/CMCS LbL assembly, significantly delayed the pH rise during refrigerated storage, maintaining a final pH of 6.28 compared to 7.28 in the control group after 5 days. The microcapsules also effectively suppressed microbial growth (total viable count (TVC) was maintained below 6 log CFU/g) and controlled lipid oxidation (thiobarbituric acid reactive substances (TBARS) values were kept at 0.62 mg malondialdehyde/kg) while better preserving texture and color stability compared to free phages. This zein/CMCS-based LbL system presents a promising strategy for advancing phage-based biopreservation in aquatic products through enhanced physical protection, sustained release, and improved stress tolerance. Full article