Search Results (668)

Accurate quantification of the apparent chloride diffusion coefficient is pivotal for predicting the service life and assessing the durability of coastal infrastructure. While existing empirical models are informative, they fundamentally overlook the influence of reinforcement. This study establishes an integrated computational framework combining XGBoost machine learning with finite element (FE) analysis to elucidate chloride transport mechanisms in reinforced concrete (RC), explicitly accounting for the presence of reinforcement. Based on 171 experimental datasets, this study developed a prediction model to estimate the apparent chloride diffusion coefficient in reinforced concrete subjected to dry–wet cycles. The diameter of rebar was innovatively incorporated as a parameter, systematically integrating seven other key influencing factors into the model. Shapley Additive Explanations (SHAP) analysis reveals that exposure duration, sampling depth, coarse-to-total aggregate ratio, and rebar diameter constitute the dominant influencing parameters. Furthermore, FE analysis reveals that the presence of rebar redistributes aggregates, forming preferential pathways that increase chloride concentration at the steel-concrete interface. This study shows that the influence of reinforcement on chloride diffusion cannot be ignored. The proposed methodology advances durability science by data-driven modeling with physics-based modeling, providing actionable strategies for marine infrastructure optimization. Full article

To accurately simulate the chloride ion diffusion process in concrete containing mineral admixtures under coupled multi-factor effects, a cellular automata (CA)-based numerical model is developed to predict the chloride ion concentration at different depths and exposure times. The proposed model incorporates the influences of spatiotemporal variability, stress state, and admixture replacement ratio into the evolution rules of chloride transport. Accordingly, the time-dependent chloride diffusion coefficient is modified to account for the effects of fly ash and slag, enabling a more realistic representation of chloride transport behavior in admixture-modified concrete. Long-term field exposure test data reported in the literature are adopted to validate the proposed model. The simulated chloride concentration profiles at various depths and exposure durations show good agreement with experimental measurements, particularly at medium-to-long exposure ages. The results demonstrate that the CA model provides a reasonable and effective way for simulating chloride ion ingress in concrete with mineral admixtures. Furthermore, under comparable strength conditions, an increase in slag replacement ratio leads to enhanced resistance against chloride ion ingress, highlighting the significant role of mineral admixtures in improving the durability performance of concrete structures. Full article

In conventional low-viscosity solvents, magnetic field effects (MFEs) in photoredox catalysis are often negligible because photogenerated radical ion pairs (RIPs) diffuse apart before significant spin evolution occurs. This study reports using ionic liquids (ILs) as a tunable homogeneous “solvent cage” to observe distinct low-field MFEs in the phenothiazine-mediated photoinduced reductive dechlorination of aryl chlorides. Experimental results demonstrate that MFEs increase significantly with bulk viscosity, reaching saturation at approximately 1000 Gs with a maximum enhancement of about 15%, consistent with the hyperfine coupling mechanism (HFCM). Femtosecond transient absorption spectroscopy (fs-TA) reveals that the ionic liquid environment effectively reduces the radical cage escape rate, matching it with the spin evolution rate. This allows the external magnetic field to intervene in the back electron transfer (BET) process. However, unlike strongly confined micellar systems, the contribution of the triplet charge recombination (TCR) pathway here is moderate, intrinsically limiting the magnetic enhancement amplitude. These findings establish that MFE magnitude is determined by both viscosity-controlled cage dynamics and the efficiency of the TCR channel, providing a mechanistic basis for designing spin-modulated homogeneous photoredox systems. Full article

The objective of this study was to experimentally quantify and analytically model chloride ion transport in high-performance concrete incorporating single and binary mineral admixtures under sustained compressive loading, thereby improving durability prediction for load-bearing concrete exposed to chloride environments. A series of accelerated chloride transport experiments was conducted on high-performance concrete subjected to sustained compressive loading. The surface strain evolution of concrete was investigated under different compressive stress ratios and admixture dosages. The effects of the admixture dosage and sustained compressive stress ratio on chloride distribution were analyzed. A chloride diffusion coefficient model that incorporated sustained compressive loading and composite mineral admixtures was established, and its validity was verified. The influences of key parameters on chloride transport in binary-blended high-performance concrete were further discussed. The results showed that the strain of ordinary concrete specimens was the largest, followed by that of high-performance concrete with a single admixture of fly ash or silica fume, and the strain of high-performance concrete with double admixtures of fly ash and silica fume was the smallest. The chloride concentration in concrete first decreased and then increased with the increase in compressive stress level. The largest change amplitude was observed in ordinary concrete, and the smallest was in high-performance concrete with double admixtures of fly ash and silica fume. An increase in the time decay coefficient caused the chloride concentration in binary-blended high-performance concrete to decrease first and then increase. When the fly ash content was kept constant, the chloride concentration gradually decreased with increasing silica fume content. When the silica fume content reached 17%, the chloride concentration at a diffusion depth of 11 mm approached zero. Full article

Chloride-induced deterioration is a major threat to the durability of marine concrete structures, especially in tidal and submerged zones. This study simulated these environments by immersing C45 concrete specimens in NaCl solutions (5%, 10%, 15%) under both constant immersion and wet–dry cycles. Compressive strength tests, low-field NMR for pore structure, chloride ion profiling, and SEM-EDS analyses were conducted. A modified chloride diffusion model was developed based on Fick’s second law, incorporating time- and concentration-dependent parameters. The results showed that higher NaCl concentrations and tidal zone exposure significantly accelerated concrete degradation. In the tidal zone, wet–dry cycles led to larger macropore formation, higher chloride penetration, and more severe microstructural damage compared to the submerged zone. Compressive strength initially increased and then declined in high-salinity environments, with strength losses reaching up to 25% under 15% NaCl after 120 days. NMR data confirmed the transformation of micropores and mesopores into macropores, especially in the tidal zone. SEM-EDS analysis revealed decalcification, gypsum formation, and Friedel’s salt accumulation on eroded surfaces. It was determined that chloride ion diffusion behavior in concrete is significantly influenced by the chloride content and diffusion concentration, as well as the exposure zone. The developed model indicates that depth increased over time and with concentration. The proposed diffusion model achieved high fitting accuracy (R² > 0.97), effectively capturing the effects of erosion age and salt; this makes it a reliable tool for predicting chloride ion ingress in marine concrete, and for supporting service life evaluation and durability design. Full article

Catheter-associated urinary tract infections are often caused by biofilm formation on device surfaces. This paper presents an antimicrobial catheter-coating hydrogel comprising p(HEMA) and carboxyl-functionalized p(HEMA-co-MA), loaded with benzalkonium chloride (BAC) to increase hydrophilicity, pH responsiveness, and antibiofilm activity. Hydrogels were prepared by free-radical polymerization, loaded with BAC via swelling, and their physicochemical properties were characterized. Furthermore, microbiological assessment focused on the detection of MIC/MBC/MFC, disk diffusion, biofilm assays, SEM imaging, and RT-qPCR sequencing were used to determine the impact on biofilm-related gene expression to evaluate antimicrobial activity against major catheter-associated urinary tract infection (CAUTI)-associated pathogens and identify the higher BAC loading p(HEMA) and enhanced hydrophilicity and pH-responsive swelling (p(HEMA-co-MA)). The two hydrogels exhibited a wide range of antimicrobial activity and provided lasting inhibition for up to 8 days. It is worth noting that the MA-functionalized hydrogel exhibited a high intrinsic antifouling property, and biofilm development was reduced by more than 85% in BAC-loaded formulations. SEM and gene-expression studies showed reduced microbial adhesion and substantial repression of virulence and biofilm-associated genes. In summary, BAC-loaded p(HEMA) and p(HEMA-co-MA) coatings exhibit strong antimicrobial and antiadhesive properties, and the incorporation of MA results in more effective biofilm suppression, which supports their future use as advanced catheter coatings to prevent the development of device-related infections. Full article

This study investigated the effects of calcium carbide slag (CCS) (0–12 wt%) incorporation on the workability, electrochemical properties, durability, and microstructure evolution of sulfoaluminate cement (SAC) mortar. Results showed that increasing CCS content reduced mortar fluidity and shortened setting time, indicating that CCS accelerates early hydration. A 9% CCS content was determined to be the optimal dosage; at 28 days, compared to the control group, this dosage group exhibited a 6.53% increase in compressive strength, a 22.47% decrease in drying shrinkage, and a 0.279% decrease in mass loss. These performance improvements stemmed from CCS’s ability to inhibit pore connectivity and limit moisture migration. Electrochemical analysis further revealed that the 9% CCS dosage group had the highest charge transfer resistance and resistivity (30.00% higher than the control group), reflecting a denser matrix and greater ion transport resistance. Consequently, chloride ion permeability was significantly reduced, with electrical flux and diffusion coefficient decreasing by 39.98% and 28.89%, respectively. Microstructural observations confirmed that CCS promotes the formation and densification of hydration products, effectively improving the internal pore structure. While 9% CCS can serve as an effective functional supplementary material, its long-term durability and sustainability still face practical application challenges. Future research should focus on establishing predictive models for chloride ion permeation lifetime and conducting quantitative sustainability assessments of CCS-SAC composites, particularly evaluating material cost, energy consumption, and carbon dioxide emissions. Full article

Concrete is widely employed in structural engineering; however, its porous nature renders it vulnerable to chloride ingress and salt freezing cycles, ultimately compromising its durability. To address this, a penetrating primer based on tetraethyl orthosilicate (TEOS) was prepared in an ethanol-water co-solvent system, and a hydrophobic topcoat of isooctyltriethoxysilane (IOTES) was obtained via emulsification. A layered application on concrete surfaces yielded a TEOS–IOTES dual-coating protection system designed to enhance water repellency and thereby improve resistance to chloride penetration and salt freeze–thaw damage. Test results show that the dual coating markedly increased hydrophobicity, giving a water contact angle of 130° and reducing water absorption rate to below 0.01 mm/min^0.5. Compared with single-layer treatments, the dual coating significantly lowered the free chloride diffusion coefficient (reached 83.74%). In terms of salt freezing cycle resistance, the dual-coating protection delayed surface scaling and increased the critical number of freeze–thaw cycles required for damage by 40%. Microstructural analyses indicate that the TEOS primer generates nano-SiO₂ and C-S-H gels, refining pores and densifying the matrix, while the IOTES topcoat forms a durable hydrophobic layer that suppresses moisture and deleterious ion transport. The synergistic “densification–hydrophobization” mechanism substantially enhances concrete durability, offering a cost-effective and efficient surface-protection strategy with promising application potential. Full article

Chloride diffusivity of concrete is essentially determined by its microstructural parameters. Establishing a reliable and accurate prediction model for chloride diffusion has become a research hotspot. In this study, a database containing 144 sets of macro–micro property parameters of concrete is established to train a Multilayer Perceptron (MLP) model. Taking the original collected data as a benchmark, data are randomly missing to simulate data incompleteness, and the models are trained using data filled by the Lagrange, K-Nearest Neighbor (KNN), and Miceforest methods. Moreover, the original data is expanded by the virtual sample generation (VSG) algorithm, based on a Gaussian mixture model (GMM) that fits the joint probability distribution of the original data to generate virtual samples preserving statistical (mean, standard deviation) and physical (e.g., porosity range, pore size ratio) consistency, thus mitigating the randomness caused by small sample sizes. Results indicate that the MLP model demonstrates excellent predictive performance: among schemes handling missing data, the model preprocessed by normalization with KNN imputation yields the best results with testing R² of 0.78; the baseline model (without missing value filling, normalized) achieves testing R² of 0.83, MAE of 0.572, and MSE of 0.424. VSG-expanded data significantly enhances the MLP model’s prediction accuracy. When expanding to 3000 groups, the testing R² reaches 0.85, a 2.4% increase compared to 1000 groups, with further improvements as the dataset expands, confirming the feasibility of the VSG algorithm for small-sample scenarios. Full article

Benzalkonium chloride (BC) is widely used as a disinfectant in the food industry; however, increasing reports of Listeria innocua isolates exhibiting tolerance to this compound highlight the need to better understand their adaptive mechanisms. This study aimed to evaluate BC tolerance in 51 L. innocua isolates originating from raw and processed meat products (n = 32) and meat-processing environments in Poland (n = 19). Phenotypic tolerance was assessed using the agar diffusion method on two media: Brain Heart Infusion (BHI) agar and Mueller–Hinton (M-H) agar supplemented with 1.2% sheep blood, across BC concentrations of 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 µg/mL, allowing the determination of minimum inhibitory concentrations (MICs). Genotypic analysis of tolerance determinants (brcABC, ermC, qacE, qacF, qacG, qacH, and qacJ) was performed by PCR. On BHI agar, MIC values ranged from 15 to 30 µg/mL, with 15 µg/mL most frequently observed, whereas on blood-supplemented M-H agar, MICs were lower (5–20 µg/mL), most commonly 10 µg/mL. Among tolerance-associated genes, qacH was the most prevalent (29% of isolates), followed by brcABC (4%) and ermC (2%), while the remaining genes were absent. These findings suggest that food products may serve as a reservoir for L. innocua isolates harboring tolerance to BC and contribute to a deeper understanding of how this species adapts to quaternary ammonium compounds. Full article

Plastic streams dominated by polyethylene (PE) including PE HD/MD (High Density/Medium Density) and PE LD/LLD (Low Density/Linear Low Density), polypropylene (PP), and polyvinyl chloride (PVC) across Europe demand a design framework that links synthesis with end of life reactivity, supporting circular economic goals and European Union waste management targets. This work integrates polymerization derived chain architecture and depolymerization mechanisms to guide selective valorization of commercial plastic wastes in the European context. Catalytic topologies such as Bronsted or Lewis acidity, framework aluminum siting, micro and mesoporosity, initiators, and strategies for process termination are evaluated under relevant variables including temperature, heating rate, vapor residence time, and pressure as encountered in industrial practice throughout Europe. The analysis demonstrates that polymer chain architecture constrains reaction pathways and attainable product profiles, while additives, catalyst residues, and contaminants in real waste streams can shift radical populations and observed selectivity under otherwise similar operating windows. For example, strong Bronsted acidity and shape selective micropores favor the formation of C₂ to C₄ olefins and Benzene, Toluene, and Xylene (BTX) aromatics, while weaker acidity and hierarchical porosity help preserve chain length, resulting in paraffinic oils and waxes. Increasing mesopore content shortens contact times and limits undesired secondary cracking. The use of suitable initiators lowers the energy threshold and broadens processing options, whereas diffusion management and surface passivation help reduce catalyst deactivation. In the case of PVC, continuous hydrogen chloride removal and the use of basic or redox co catalysts or ionic liquids reduce the dehydrochlorination temperature and improve fraction purity. Staged dechlorination followed by subsequent residue cracking is essential to obtain high quality output and prevent the release of harmful by products within European Union approved processes. Framing process design as a sequence that connects chain architecture, degradation chemistry, and operating windows supports mechanistically informed selection of catalysts, severity, and residence time, while recognizing that reported selectivity varies strongly with reactor configuration and feed heterogeneity and that focused comparative studies are required to validate quantitative structure to selectivity links. In European post consumer sorting chains, PS and PC are frequently handled as separate fractions or appear in residues with distinct processing routes, therefore they are not included in the polymer set analyzed here. Polystyrene and polycarbonate are outside the scope of this review because they are commonly handled as separate fractions and are typically optimized toward different product slates than the gas, oil, and wax focused pathways emphasized here. Full article

Atomic layer deposition (ALD) was employed to fabricate single-layer Al₂O₃, single-layer ZrO₂, and Al₂O₃/ZrO₂ nanolaminate coatings on SUS304 to enhance corrosion protection in chloride-containing environments. All coatings were deposited at 250 °C using optimized self-limiting ALD processes, and the total film thickness was controlled at approximately 54 nm for a fair comparison. Structural characterization revealed that Al₂O₃ films remained amorphous, whereas ZrO₂ films exhibited a thickness-dependent transition from amorphous to crystalline phases. In the nanolaminate structures, thinner ZrO₂ sublayers (<9 nm) retained amorphous or locally nanocrystalline characteristics, while thicker ZrO₂ sublayers (15 nm) developed polycrystalline features with increased grain boundary density. Electrochemical corrosion tests conducted in 3.5 wt% NaCl solution demonstrated that the Al₂O₃/ZrO₂ nanolaminate coatings exhibited significantly lower corrosion current densities and delayed pitting corrosion compared to single-layer coatings. Among all samples, the [Al₂O₃ (15 nm)/ZrO₂ (3 nm)] × 3 nanolaminate showed the best corrosion resistance, with the lowest corrosion current density (I_corr = 6.20 nA/cm²) and the highest protective efficiency (98.34%). These results highlight the critical role of nanolaminate architecture and sublayer crystallinity in suppressing ionic diffusion and provide an effective strategy for designing ultrathin, high-performance corrosion barrier coatings for stainless steel. Full article

This paper presents a validated, data-driven framework for the sustainable rehabilitation of corrosion-damaged marine infrastructure, demonstrated through a comprehensive study on a historic coastal structure. The implemented three-phase methodology—integrating advanced condition assessment, evidence-based intervention design, and rigorous performance validation—successfully addressed severe chloride-induced deterioration. Diagnostic quantification revealed that 30% of the primary substructure was severely compromised, with chloride concentrations reaching 1.94% by weight (970% above the corrosion threshold) and half-cell potential mapping confirming a >90% probability of active corrosion in critical elements. Guided by this data, a synergistic intervention combining galvanic cathodic protection, high-performance coatings, and structural strengthening was deployed. Post-repair validation confirmed exceptional outcomes: a complete electrochemical repassivation (potential shift from −385 mV to −185 mV), a 97.3% reduction in chloride diffusion rates, a 250% increase in surface resistivity, and the restoration of structural capacity to 115% of design specifications. The framework achieved a 65% reduction in projected lifecycle costs while establishing a new paradigm for preserving marine infrastructure through evidence-based, multi-mechanism strategies that ensure long-term durability and economic viability. Full article

Gliomas are the most common malignant primary brain tumors in adults. The treatment of high-grade gliomas is very limited due to their diffuse infiltration, high plasticity, and resistance to conventional therapies. Although they were long considered passive massive lesions, they are now regarded as functionally integrated components of neural circuits, as they form authentic electrochemical synapses with neurons. This allows them to mimic neuronal activity to drive tumor growth and invasion. Ultrastructural studies show presynaptic vesicles in neurons and postsynaptic densities in glioma cell membranes, while electrophysiological recordings detect postsynaptic currents in tumor cells. Tumor microtubules (TMs), dynamic cytoplasmic protrusions enriched in AMPA receptors, are the structures responsible for glioma–glioma and glioma–neuron connectivity, also contributing to treatment resistance and tumor network integration. In these connections, neurons release glutamate that mainly activates their AMPA receptors in glioma cells, while gliomas release excess glutamate, causing excitotoxicity, altering the local excitatory-inhibitory balance, and promoting a hyperexcitable and pro-tumorigenic microenvironment. In addition, certain gliomas, such as diffuse midline gliomas, have altered chloride homeostasis, which makes GABAergic signaling depolarizing and growth promoting. Synaptogenic factors, such as neuroligin-3 and BDNF, further enhance glioma proliferation and synapse formation. These synaptic and paracrine interactions contribute to cognitive impairment, epileptogenesis, and resistance to surgical and pharmacological interventions. High functional connectivity within gliomas correlates with shorter patient survival. Therapies such as AMPA receptor antagonists (perampanel), glutamate release modulators (riluzole or sulfasalazine), and chloride cotransporter inhibitors (NKCC1 blockers) aim to improve outcomes for patients. Full article

Thick (900–1500 µm), crack-free lithium manganese oxide (LMO) electrodes with a polyvinylidene fluoride (PVDF)-based polymer electrolyte were prepared using an innovated slurry casting method. The selectivity and intercalation capacity of the thick electrodes of 900–1500 μm were evaluated in aqueous chloride solutions containing main cations in synthetic Salar de Atacama brine using cyclic voltammetry (CV) measurements. The CV data indicated that a high Li⁺ selectivity of Li/Na = 152.7 could be achieved under potentiostatic conditions. With the thickest electrode, while the mass specific intercalation capacity was 6.234 mg per gram of LMO, the area specific capacity was increased by 3–11 folds compared to that for conventional thin electrodes to 0.282 mg per square centimeter. In addition, 82% of capacity was retained over 30 intercalation/dis-intercalation cycles. XRD and electrochemical analyses revealed that both Faradaic diffusion-controlled or battery-like intercalation and Faradaic non-diffusion controlled or pseudocapacitive intercalation contributed to the capacity and selectivity. This work demonstrates a practical technology for thick electrode fabrication that promises to result in a significant reduction in manufacturing and operational costs for lithium extraction from brines. Full article