Search Results (1,269)

This paper presents the development and characteristics of geopolymer foams modified with paraffin-based phase change materials (PCMs) encapsulated in diatomite. The aim was to increase both the thermal insulation and heat storage capacity of the foams while maintaining sufficient mechanical strength for construction applications. Eleven variants of composites with different PCM fractions (5–10% by mass) and grain sizes (<1.6 mm to >2.5 mm) were synthesized and tested. The inclusion of PCM encapsulated in diatomite modified the porous structure: the total porosity increased from 6.6% in the reference sample to 19.6% for the 1.6–1.8 mm_10% wt. variant, with pore diameters ranging from ~4 to 280 µm. Thermal conductivity (λ) ranged between 0.090–0.129 W/m·K, with the lowest values observed for composites 2.0–2.5 mm_5–10% wt. (≈0.090–0.091 W/m·K), which also showed high thermal resistance (R ≈ 0.287–0.289 m²·K/W). The specific heat (Cp) increased from 1.28 kJ/kg·K (reference value) to a maximum value of 1.87 kJ/kg·K for the 2.0–2.5 mm_10% mass variant, confirming the effective energy storage capacity of PCM-modified foams. Mechanical tests showed compressive strength values in the range of 0.7–3.1 MPa. The best structural performance was obtained for the 1.6–1.8 mm_10% wt. variant (3.1 MPa), albeit with a higher λ (≈0.129 W/m·K), illustrating the classic trade-off between porosity-based insulation and mechanical strength. SEM microstructural analysis and mercury porosimetry confirmed the presence of mesopores, which determine both thermal and mechanical properties. The results show that medium-sized PCM fractions (1.6–2.0 mm) with moderate content (≈10% by weight) offer the most favorable compromise between insulation and strength, while thicker fractions (2.0–2.5 mm) maximize thermal energy storage capacity. These findings confirm the possibility of incorporating natural PCMs into geopolymer foams to create multifunctional materials for sustainable and energy-efficient building applications. A unique contribution to this work is the use of diatomite as a natural PCM carrier, ensuring stability, compatibility, and environmental friendliness compared to conventional encapsulation methods. Full article

This study reports on green-synthesized zinc oxide nanoparticles (ZnONPs), focusing on their physicochemical characterization, photocatalytic properties, and agricultural applications. Dynamic light scattering (DLS) analysis revealed a mean hydrodynamic diameter of 337.3 nm and a polydispersity index (PDI) of 0.400, indicating moderate polydispersity and nanoparticle aggregation, typical of biologically synthesized systems. High-resolution transmission electron microscopy (HR-TEM) showed predominantly spherical particles with an average diameter of ~28 nm, exhibiting slight agglomeration. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of zinc and oxygen, while X-ray diffraction (XRD) analysis identified a hexagonal wurtzite crystal structure with a dominant (002) plane and an average crystallite size of ~29 nm. Photoluminescence (PL) spectroscopy displayed a distinct near-band-edge emission at ~462 nm and a broad blue–green emission band (430–600 nm) with relatively low intensity. The ultraviolet–visible spectroscopy (UV–Vis) absorption spectrum of the synthesized ZnONPs exhibited a strong absorption peak at 372 nm, and the optical band gap was calculated as 2.67 eV using the Tauc method. Fourier-transform infrared spectroscopy (FTIR) analysis revealed both similarities and distinct differences to the pigeon extract, confirming the successful formation of nanoparticles. A prominent absorption band observed at 455 cm⁻¹ was assigned to Zn–O stretching vibrations. X-ray photoelectron spectroscopy (XPS) analysis showed that raw pigeon droppings contained no Zn signals, while their extract provided organic biomolecules for reduction and stabilization, and it confirmed Zn²⁺ species and Zn–O bonding in the synthesized ZnONPs. Photocatalytic degradation assays demonstrated the efficient removal of pollutants from sewage water, leading to significant reductions in total dissolved solids (TDS), chemical oxygen demand (COD), and total suspended solids (TSS). These results are consistent with reported values for ZnO-based photocatalytic systems, which achieve biochemical oxygen demand (BOD) levels below 2 mg/L and COD values around 11.8 mg/L. Subsequent reuse of treated water for irrigation yielded promising agronomic outcomes. Wheat and barley seeds exhibited 100% germination rates with ZnO NP-treated water, which were markedly higher than those obtained using chlorine-treated effluent (65–68%) and even the control (89–91%). After 21 days, root and shoot lengths under ZnO NP irrigation exceeded those of the control group by 30–50%, indicating enhanced seedling vigor. These findings demonstrate that biosynthesized ZnONPs represent a sustainable and multifunctional solution for wastewater remediation and agricultural enhancement, positioning them as a promising candidate for integration into green technologies that support sustainable urban development. Full article

Objective: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), a variant of zirconia (ZrO₂), has attracted interest as a substitute for titanium in dental and orthopedic implants, valued for its biocompatibility and aesthetics that resemble natural teeth. However, its bioinert surface limits osseointegration, making surface modifications such as calcium phosphate (CaP) coatings highly relevant. Materials and methods: The review process adhered to the PRISMA guidelines. Electronic searches of PubMed, Scopus, Web of Science, Embase, and Cochrane Library (July 2025) identified studies evaluating CaP-coated zirconia implants. Eligible studies included in vitro, in vivo, and preclinical investigations with a control group. Data on coating type, deposition method, and biological outcomes were extracted and analyzed. Results: A total of 27 studies were analyzed, featuring different calcium phosphate (CaP) coatings including β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), octacalcium phosphate (OCP), and various composites. These coatings were applied using diverse techniques such as RF magnetron sputtering, sol–gel processing, biomimetic methods, and laser-based approaches. In multiple investigations, calcium phosphate coatings enhanced osteoblast attachment, proliferation, alkaline phosphatase (ALP) expression, and bone-to-implant contact (BIC) relative to unmodified zirconia surfaces. Multifunctional coatings incorporating growth factors, antibiotics, or nanoparticles showed additional benefits. Conclusion: CaP coatings enhance the bioactivity of zirconia implants and represent a promising strategy to overcome their inertness. Further standardized approaches and long-term studies are essential to verify their translational relevance. Full article

The growing demand for lightweight and reliable structures across aerospace, automotive, marine, and civil engineering has driven significant advances in polymer adhesive technology. These materials serve dual roles, functioning as matrices in composites and as structural bonding agents, where they must balance strength, toughness, durability, and sometimes sustainability. Recent review efforts have greatly enriched understanding, yet most approach the topic from specialized angles—whether emphasizing nanoscale toughening, multifunctional formulations, sustainable alternatives, or microscopic failure processes in bonded joints. While such perspectives provide valuable insights, they often remain fragmented, leaving open questions about how nanoscale mechanisms translate into macroscopic reliability, how durability evolves under realistic service conditions, and how mechanical responses interact across different loading modes. To address this, the present review consolidates knowledge on the performance of polymer adhesives under tension, shear, fracture, fatigue, creep, and impact. By integrating experimental findings with computational modeling and emerging data-driven approaches, it situates localized mechanisms within a broader structure–performance framework. This unified perspective not only highlights persistent gaps—such as predictive modeling of complex failure, scalability of nanomodified systems, and long-term durability under coupled environments—but also outlines strategies for developing next-generation adhesives capable of delivering reliable, high-performance bonding solutions for demanding applications. Full article

Background/Objectives: Fetuin-A is a multifunctional glycoprotein involved in metabolic and inflammatory regulation. Although its role in insulin resistance, type 2 diabetes, and cardiovascular disease is well recognized, its relationship with pregnancy-related body mass changes remains unclear. This study aimed to explore associations between maternal BMI dynamics during and shortly after pregnancy and serum fetuin-A concentrations. Methods: Fifty-five healthy Caucasian women with term singleton pregnancies were enrolled. BMI was recorded at three time points: pre-pregnancy, before delivery, and 48 h postpartum. Based on ΔBMI (postpartum minus pre-pregnancy BMI), participants were divided into two groups: ΔBMI ≤ 1 kg/m² (n = 32) and ΔBMI > 1 kg/m² (n = 23). Serum fetuin-A levels were measured before delivery and postpartum using ELISA. Additional laboratory parameters and body composition were assessed postpartum via standard tests and bioelectrical impedance analysis (BIA). Results: No significant differences were found between groups in BMI at any single time point or in laboratory or BIA-derived parameters. However, all three BMI change indices (ΔBMI_gestational, ΔBMI_puerperal, and ΔBMI) differed significantly between groups. Fetuin-A concentrations did not differ significantly between groups. Importantly, fetuin-A levels decreased significantly after delivery in both groups, suggesting a potential role of the placenta in its regulation. A significant correlation was observed between pre-delivery fetuin-A and postpartum uric acid in Group ΔBMI > 1 kg/m² (p = 0.016), indicating a possible link in women with greater gestational weight gain. Conclusions: While fetuin-A was not directly associated with BMI changes, its peripartum dynamics and correlation with uric acid may reflect underlying metabolic-inflammation pathways. ΔBMI indices may offer a more individualized measure of weight dynamics in pregnancy research. Full article

Wound infection is one of the most critical factors affecting the healing process. Therefore, the development of wound dressings with excellent antibacterial effects has become a research hotspot in the current academic field. We prepared AgNPs (silver nanoparticles) via a redox method, combined them with Poly(vinyl alcohol)/chitosan (PVA/CS), and dried the mixture into a film to fabricate a silver-loaded hydrogel film dressing with excellent antibacterial properties. Uniaxial tensile tests on the samples revealed that the prepared film dressings exhibited good mechanical properties, preventing fracture caused by external forces. Protein adsorption experiments indicated their favorable protein adsorption performance, which can adsorb microorganisms on the external surface of the dressing. By leveraging the bactericidal mechanism of AgNPs, the dressing achieves efficient antibacterial effects. Additionally, the dressing prepared by this method features good transparency, facilitating routine observation of the wound area without removing the dressing and maintaining a sterile environment for an extended period. Finally, we verified the drug loading and drug release capabilities of the dressing, and found that it has good drug loading capacity and drug release effect. This preliminarily proves its effectiveness and provides more possibilities for subsequent research on composite drugs. This study provides new insights for exploring the clinical application of multifunctional silver-loaded wound dressings. Full article

This study presents a green, single-step method for synthesizing nanocomposites based on reduced graphene oxide (RGO) and gold nanoparticles (AuNPs), using sodium citrate as a mild reducing and stabilizing agent. AuNPs were generated from chloroauric acid (HAuCl₄) directly on the surface of graphene oxide (GO), which was simultaneously reduced to RGO. Structural characterization via Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM) and Selected Area Electron Diffraction (SAED) confirms spherical AuNPs (10–60 nm) distributed on RGO sheets, with indications of nanoparticle aggregation. Dynamic Light Scattering (DLS) and zeta potential analysis support these findings, suggesting colloidal instability with higher RGO content. Biological evaluation demonstrates dose-dependent cytotoxicity in HaCaT keratinocytes, with IC₅₀ values (half maximal inhibitory concentration) decreasing as RGO content is increased. At moderate dilutions (1–25 µL/100 µL), the composites show acceptable cell viability (>70%). Antibacterial assays reveal strong synergistic effects against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, with sample RGO/Au 0.500/0.175 g/L showing complete E. coli inhibition at low Au content (0.175 g/L). The composite retained activity even in protein-rich media, suggesting potential for antimicrobial applications. These findings highlight the potential of RGO/AuNPs composites as multifunctional materials for biomedical uses, particularly in antimicrobial coatings and targeted therapeutic strategies. Full article

With rising living standards, consumer demand for fresher food continues to increase. Consequently, the development of multifunctional packaging materials that enable real-time freshness monitoring, delay spoilage, and ensure environmental sustainability has become a central research focus. The present study developed an antibacterial and pH-responsive smart packaging film, formulated from a κ-carrageenan/gelatin (CG) matrix. This film incorporated anthocyanins extracted from red onion skin (ROSA) and citronella essential oil encapsulated in β-cyclodextrin (OBDs) as functional additives, herein referred to as the CGR/OBDs composite film. The composite films exhibited strong pH sensitivity, ammonia responsiveness, color stability, effective barrier properties, and notable antioxidant activity (96.4% ABTS and 79.3% DPPH radical scavenging rates). The sustained release of citronella essential oil over approximately 40 h conferred excellent antibacterial performance, with inhibition rates of 94.8% against Staphylococcus aureus (S. aureus) and 91.6% against Escherichia coli (E. coli). Application in shrimp preservation further demonstrated an extended shelf life and real-time freshness monitoring through distinct colorimetric shifts. The findings highlight the potential of CGR/OBDs films as visual indicators for food freshness in intelligent packaging, offering a promising strategy to enhance food safety and reduce waste. Full article

Hexagonal boron nitride (h-BN) possesses a unique combination of a wide bandgap, high thermal conductivity, and chemical inertness, making it a key insulating and thermal management material for advanced electronics and nanocomposites. However, its intrinsic hydrophobicity and strong interlayer van der Waals forces severely limit exfoliation efficiency and dispersion stability, particularly in scalable liquid-phase processes. Here, we report a synergistic exfoliation strategy that integrates acid-induced hydroxylation with gallium (Ga) intercalation to achieve high-yield (>80%) production of ultrathin (<4 nm) hydrophilic h-BN nanosheets. Hydroxylation introduces abundant -OH groups, expanding interlayer spacing and significantly increasing surface polarity, while Ga intercalation leverages its native Ga₂O₃ shell to form strong interfacial interactions with hydroxylated basal planes. This oxide-mediated adhesion facilitates efficient layer separation under mild sonication, yielding nanosheets with well-preserved lateral dimensions and exceptional dispersion stability in polar solvents. Comprehensive characterization confirms the sequential chemical and structural modifications, revealing the crucial roles of hydroxylation-induced activation and Ga₂O₃ assisted wettability enhancement. This combined chemical activation–soft metallic intercalation approach provides a scalable, solution-processable route to high-quality h-BN nanosheets, opening new opportunities for their integration into dielectric, thermal interface, and multifunctional composite systems. Full article

Global waste generation is a ubiquitous challenge, driving a paradigm shift towards viewing waste as a valuable resource for a circular economy across diverse sectors. While innovative waste-to-resource pathways are crucial, rigorous Life Cycle Assessment (LCA) is essential to ensure the pathways are an important part of current practices. However, LCA application to waste valorization varies, leading to incomparable results due to differing methodological choices. This paper examines three key nuances in waste-as-resource LCAs: the zero-burden assumption, the biogenic carbon neutrality assumption, and the benchmark assumption for emissions avoidance. Using a waste gasification to hydrogen case study, we demonstrate how these methodological decisions impact LCA outcomes. Our findings reveal that waste composition significantly influences the results and highlight challenges associated with biogenic carbon accounting under various system boundary assumptions. Emissions avoidance accounting requires multi-functional unit perspectives and robust benchmark selection. This paper clarifies these accounting approaches, empirically illustrates their influence, and discusses broad implications for accurate sustainability assessment, emphasizing the critical role of transparent LCA choices for effective policy and investment in circular economy solutions. Full article

Wound healing is a complex, multifaceted biological process that plays a vital role in recovery and overall quality of life. However, conventional wound care methods often prove insufficient, resulting in delayed healing, higher infection risk, and other complications. In response, biomaterials—especially hydrogels—have gained attention for their advanced wound management capabilities, which support wound healing by maintaining moisture, mimicking the extracellular matrix (ECM), and enabling targeted drug delivery triggered by wound-specific signals. They frequently carry antimicrobial or anti-inflammatory agents, promote blood vessel and nerve regeneration, and are biocompatible with customizable properties suited to different healing stages. Natural hydrogels, derived from polysaccharides, proteins, and peptides, offer several advantages over synthetic options, including inherent bioactivity, enzymatic degradability, and cell-adhesive qualities that closely resemble the native ECM. These features facilitate cell interaction, modulate inflammation, and speed up tissue remodeling. Moreover, natural hydrogels can be engineered as delivery systems for therapeutic agents like antimicrobial compounds, nanoparticles, growth factors, and exosomes. This review discusses recent advances in the use of natural hydrogels as multifunctional wound dressings and delivery platforms, with a focus on their composition, mechanisms of action, and potential for treating chronic and infected wounds by incorporating antimicrobial and regenerative additives such as silver and zinc oxide nanoparticles. Full article

This review summarizes recent advances in multifunctional metamaterials (MF-MMs) for electromagnetic (EM) wave absorption. MF-MMs overcome the key limitations of conventional absorbers—such as narrow bandwidth, limited functionality, and poor environmental adaptability—offering enhanced protection against EM security threats in radar, aerospace, and defense applications. This review focuses on an integrated structure-material-function co-design strategy, highlighting advances in three-dimensional (3D) lattice architectures, composite laminates, conformal geometries, bio-inspired topologies, and metasurfaces. When synergized with multicomponent composites, these structural innovations enable the co-regulation of impedance matching and EM loss mechanisms (dielectric, magnetic, and resistive dissipation), thereby achieving broadband absorption and enhanced multifunctionality. Key findings demonstrate that 3D lattice structures enhance mechanical load-bearing capacity by up to 935% while enabling low-frequency broadband absorption. Composite laminates achieve breakthroughs in ultra-broadband coverage (1.26–40 GHz), subwavelength thickness (<5 mm), and high flexural strength (>23 MPa). Bio-inspired topologies provide wide-incident-angle absorption with bandwidths up to 31.64 GHz. Metasurfaces facilitate multiphysics functional integration. Despite the significant potential of MF-MMs in resolving broadband stealth and multifunctional synergy challenges via EM wave absorption, their practical application is constrained by several limitations: limited dynamic tunability, incomplete multiphysics coupling mechanisms, insufficient adaptability to extreme environments, and difficulties in scalable manufacturing and reliability assurance. Future research should prioritize intelligent dynamic response, deeper integration of multiphysics functionalities, and performance optimization under extreme conditions. Full article

Veneer-based wood composites are widely used for interior applications, yet their high flammability and smoke emission significantly limit their safe use in buildings. In this study, a multifunctional flame-retardant polyethylene adhesive film was developed via melt blending and hot pressing of a mixture of amino trimethylene phosphonic acid (ATMP), hydroxyethylidene diphosphonic acid (HDEP), melamine (MEL), and sodium alginate (SA). This film was laminated onto veneers to fabricate flame-retardant decorative plywood. Simultaneously, wood scrimber units for structural applications were prepared by impregnating wood with a flame-retardant system consisting of sodium silicate (Ss) and sodium tetraborate (St). These treated components were integrated to form a flame-retardant wood scrimber/plywood composite (AHM-S), with the wood scrimber as the core layer and the treated plywood as surface layers. Compared to the control, the AHM-S composite showed a 44.1% reduction in the second peak heat release rate (pk-HRR2), a 22.6% decrease in total heat release (THR), and a 12.7% reduction in maximum flame spread distance (MD_300°C). Moreover, the time to reach 275 °C on the unexposed side (T_275°C) was extended by 90.2%. These improvements are attributed to the synergistic flame-retardant effects of the surface film and impregnated core, which jointly suppress flame spread and delay thermal degradation. The composite demonstrates promising fire safety and mechanical performance for engineered wood applications. Full article

Polymer network-based nanogels (NGs) and microgels (MGs) have emerged as highly versatile platforms for advanced drug delivery, owing to their tunable architecture, biocompatibility, and responsiveness to diverse stimuli. This review presents a comprehensive and structured analysis of NG/MGs, encompassing their classification based on polymer origin, crosslinking mechanisms, composition, charge, stimuli-responsiveness, and structural architecture. We detail synthesis strategies—including inverse microemulsion and radiation-induced polymerization—and highlight key characterization techniques essential for evaluating physicochemical and functional properties. Emphasis is placed on the design-driven applications of NG/MGs in overcoming biological barriers and enabling targeted therapies, particularly in cancer, inflammation, diabetes, and viral infections. Multifunctional NGs integrating therapeutic and diagnostic capabilities (theranostics), as well as emerging platforms for immunotherapy and personalized medicine, are critically discussed. Finally, we address translational challenges and future directions, including scalable manufacturing, regulatory considerations, and integration with smart diagnostics. This review aims to serve as a foundational resource for researchers and clinicians developing next-generation NG/MG-based therapeutics. Full article

The (AlFeCoNi)C high-entropy alloy carbide films (HECFs) with tunable carbon contents were fabricated by magnetron sputtering to investigate the carbon-driven structural evolution and its coupling effects on mechanical and chemical properties. With increasing carbon incorporation (0–47.6 at.%), the HECFs formed a composite structure of amorphous phase and BCC nanocrystalline phase, as evidenced by XRD and TEM. Atom probe tomography (APT) reveals Al segregation in the film. Remarkably, the wear rate decreases exponentially from 4.8 × 10⁻⁵ to 6.7 × 10⁻⁶ mm³/N·m, attributed to the amorphous carbon phase acting as solid lubricant. Simultaneously, the corrosion current density reduces by two orders of magnitude (7.2 × 10⁻⁸ A/cm² in 3.5% NaCl), benefiting from the amorphous network inhibiting ion diffusion pathways. This work establishes a carbon-content–property correlation paradigm for designing multifunctional HEA films in extreme environments. Full article