Search Results (8,837)

The rapid rise of the silver economy in the new era has become a new driving force for socio-economic development. From the perspective of Marxist political economy theory, this paper analyzes the intrinsic logic of the silver economy’s development through three dimensions: surplus value, labor market, and capital. The study finds that the silver economy in the new era faces challenges such as insufficient supply of high-quality elderly care services, simultaneous shortages in both total talent quantity and structural imbalances, and contradictions between capital’s profit-seeking nature and social welfare. By introducing the multiple streams model, the paper elucidates the coupling process of these three streams and the timing of policy window openings. It proposes targeted strategies, including strengthening technological innovation, deepening labor market reforms, and optimizing capital allocation, to promote the robust development of China’s silver economy and inject strong momentum into sustainable and high-quality economic growth. Full article

In this study, a Ag/ZrO₂ hybrid coating prepared by the sol–gel method on a β-type Ti45Nb alloy was applied by the spin coating technique, and the microstructural, mechanical, electrochemical, and tribological properties of the surface were evaluated in a multi-dimensional manner. The hybrid solution was prepared using zirconium propoxide and silver nitrate and stabilized through a low-temperature two-stage annealing protocol. The crystal structure of the coating was determined by XRD, and the presence of dense tetragonal ZrO₂ phase and crystalline Ag phases was confirmed. SEM-EDS analyses revealed a compact coating structure of approximately 1.8 µm thickness with homogeneously distributed Ag nanoparticles on the surface. As a result of the electrochemical corrosion tests, it was determined that the open circuit potential shifted to more noble values, the corrosion current density decreased, and the corrosion rate decreased by more than 70% on the surfaces where the Ag/ZrO₂ coating was applied. In the tribological tests, a decrease in the coefficient of friction, narrowing of wear marks, and significant reduction in surface damage were observed in dry and physiological (HBSS) environments. The findings revealed that the Ag/ZrO₂ hybrid coating significantly improved the surface performance of the Ti45Nb alloy both mechanically and electrochemically and offers high potential for biomedical implant applications. Full article

Nanoparticles (NPs) synthesised through biogenic routes have emerged as a sustainable and innovative platform for biomedical applications such as antibacterial, anticancer, antiviral, anti-inflammatory, drug delivery, wound healing, and imaging diagnostics. Among these, silver nanoparticles (AgNPs) have attracted significant attention due to their unique physicochemical properties and therapeutic potential. This review examines the biogenic synthesis of AgNPs, focusing on microbial, plant-based, and biomolecule-assisted approaches. It highlights how reaction conditions, such as pH, temperature, and media composition, influence nanoparticle size, shape, and functionality. Particular emphasis is placed on microbial synthesis for its eco-friendly and scalable nature. The mechanisms of AgNP formation and their structural impact on biomedical performance are discussed. Key applications are examined including antimicrobial therapies, cancer treatment, drug delivery, and theranostics. Finally, the review addresses current challenges, such as reproducibility, scalability, morphological control, and biosafety, and outlines future directions for engineering AgNPs with tailored properties, paving the way for sustainable and effective next-generation biomedical solutions. Full article

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen capable of surviving and replicating within macrophages, which causes foodborne diseases such as gastroenteritis. To develop a strategy against intracellular bacteria in macrophages, we designed silver-loaded biodegradable polymer nanoparticles functionalized with S. Typhimurium membrane vesicles (MVs). Silver nanoparticles (Ag NPs) were initially encapsulated within biodegradable poly(lactic-co-glycolic) nanoparticles (Ag-P NPs), which were then surface-modified with polyethyleneimine to form Ag-PP NPs. These were subsequently fused with S. Typhimurium MVs via a sonication method to generate Ag-PP@MV NPs. The resulting MV-coated nanoparticles displayed a similar protein profile to that of native MVs and exhibited antibacterial activity against intracellular S. Typhimurium. Notably, the enhanced cellular uptake of the MV-modified NPs contributed to their intracellular bactericidal efficacy. This study highlights MV modification as a promising strategy to improve NP delivery to macrophages for treating persistent intracellular infections. Full article

Climate change has intensified over recent decades, prompting shifts in forest management strategies, particularly in the Sudetes region of Poland, where native species like Norway spruce (Picea abies), European beech (Fagus sylvatica), and silver fir (Abies alba) have historically dominated. To address these changes, non-native species such as Douglas fir (Pseudotsuga menziesii) have been introduced as potential alternatives. This study, conducted in the Jugów and Świerki forest districts, compared the soil properties and water retention capacities of Douglas fir (Dg) and Norway spruce (Sw) stands (age classes from 8–127 years) in the Fresh Mountain Mixed Forest Site habitat. Field measurements included temperature, humidity, organic matter content, water capacity, and granulometric composition. Results indicate that, in comparison to Sw stands, Dg stands were consistently linked to soils that were naturally finer textured. The observed hydrological changes were mostly supported by these textural differences: In all investigated circumstances, Dg soils demonstrated greater water retention, displaying a water capacity that was around 5% higher. In addition to texture, Dg stands showed reduced soil water repellency and a substantially greater organic matter content (59.74% compared to 27.91% in Sw), which further enhanced soil structure and moisture retention. Conversely, with increasing climatic stress, Sw soils, with coarser textures and less organic matter, showed decreased water retention. The study highlights the importance of species selection in sustainable forest management, especially under climate change. Future research should explore long-term ecological impacts, including effects on microbial communities, nutrient cycling, and biodiversity, to optimize forest resilience and sustainability. Full article

This study presents a comprehensive evaluation and an equivalent circuit modeling of the skin–electrode impedance characteristics of three types of ultra-thin tattoo electrodes, all based on Parylene C nanofilms but with different active materials: Gold, Silver, and PEDOT:PSS. Their performance was compared to standard disposable Ag/AgCl electrodes. Impedance measurements were carried out on six human subjects under controlled conditions, assessing the frequency response in the range of 20 Hz to 1 kHz. For each subject, the impedance was recorded six times over one hour to investigate the stability and the temporal performance. The collected data were subsequently analyzed to model the electrical properties and interface behavior of each electrode type. The findings demonstrate that the tattoo electrodes offer impedance levels comparable to those of Ag/AgCl electrodes (in the order of tens of kΩ at 20 Hz), while providing additional benefits such as enhanced conformability, improved skin adhesion, and reduced skin irritation during use. Furthermore, the modeling of the skin–electrode interface through a more detailed equivalent circuit than the single time constant model enables a more detailed interface analysis and description, with fitting algorithm R² scores of about 0.999 and 0.979 for the impedance magnitude and impedance phase, respectively. The proposed equivalent circuit offers valuable insights for optimizing electrode design, supporting the potential of Parylene C-based tattoo electrodes as promising alternatives for next-generation wearable bioelectronic applications. Full article

Electrostatic separation is a promising technology for the recovery of valuable metals from electronic waste, particularly from printed circuit boards (PCBs). This study explores the application of electrostatic separation for the selective recovery of metallic and non-metallic fractions from crushed PCBs (PCBs). The process exploits the differences in electrical properties between conductive metals and non-conductive polymers and ceramics, facilitating their separation through applied electric fields. The raw materials were pre-treated via mechanical comminution using shredders and hammer mills to achieve an optimal particle size distribution (<3 mm), which enhances separation efficiency. Ferrous materials were removed prior to electrostatic separation to improve process selectivity. Key operational parameters, including particle size, charge accumulation, environmental conditions, and separation efficiency, were systematically analysed. The results demonstrate that electrostatic separation effectively recovers high-value metals such as copper and gold while minimizing material losses. Additionally, the process contributes to the sustainability of e-waste recycling by enabling the recovery of non-metallic fractions for potential secondary applications. This work underscores the significance of electrostatic separation as a viable technique for e-waste management and highlights optimization strategies for enhancing its performance in large-scale recycling operations. Full article

Urban parks are an integral component of cities; however, they are susceptible to heavy metal contamination from anthropogenic sources. Here, we investigated the moss Pleurozium schreberi and tree leaves as bioindicators for monitoring heavy metal contamination in urban parks. We determined heavy metal concentrations in P. schreberi, leaf tissues of selected tree species, and soil samples collected from various locations within a designated urban parks. The order of heavy metal accumulation was Zn > Pb > Cr > Cu > Ni > Cd > Hg in soil and Zn > Cu > Pb > Cr > Ni > Cd > Hg in P. schreberi. The order was Zn > Cu > Cr > Ni > Pb > Cd > Hg in linden and sycamore leaves, while birch leaves displayed a similar order but with slightly more Ni than Cr. The heavy metal concentration in the tested soils correlated positively with finer textures (clay and silt) and negatively with sand. The highest metal accumulation index (MAI) was noted in birch and P. schreberi, corresponding to the highest total heavy metal accumulation. The bioconcentration factor (BAF) was also higher in P. schreberi, indicating a greater ability to accumulate heavy metals than tree leaves, except silver birch for Zn in one of the parks. Silver birch displayed the highest phytoremediation capacity among the analysed tree species, highlighting its potential as a suitable bioindicator in heavy metal-laden urban parks. Our findings revealed significant variation in heavy metal accumulation, highlighting the potential of these bioindicators to map contamination patterns. Full article

This study evaluated the antimicrobial efficacy of cefiderocol and various forms of silver (ionic and nanoparticulate) as potential components of wound-dressing reagents against both reference and multidrug-resistant (MDR) Gram-negative bacteria. The anticipated synergistic effect between cefiderocol and nanosilver was not consistently observed; in fact, for reference strains, the combination was less effective than cefiderocol alone. However, in MDR and cefiderocol-resistant A. baumannii strains, combining both agents enhanced antibacterial efficacy. Notably, the effectiveness of silver did not increase with concentration, and low or medium nanosilver concentrations were often more effective. Mechanistically, high concentrations of silver may antagonize cefiderocol’s action by inhibiting bacterial surface proteins involved in siderophore-mediated uptake. Generalized linear modeling confirmed that the strain type, silver form, concentration, and their interactions significantly influenced inhibition zones. These findings highlight the importance of agent selection, concentration, and formulation in designing effective antimicrobial wound dressings. They also suggest that further research is needed to optimize such combination therapies for clinical use. Full article

This study investigates the development of silver (Ag)-doped zirconia (ZrO₂) coatings deposited on 316LVM stainless steel via the unbalanced magnetron sputtering technique. The oxygen content in the Ar/O₂ gas mixture was systematically varied (12.5%, 25%, 37.5%, and 50%) to assess its influence on the resulting coating properties. In response to the growing demand for biomedical implants with improved durability and biocompatibility, the objective was to develop coatings that enhance both wear and corrosion resistance in physiological environments. The effects of silver incorporation and oxygen concentration on the structural, tribological, and electrochemical behavior of the coatings were systematically analyzed. X-ray diffraction (XRD) was employed to identify crystalline phases, while atomic force microscopy (AFM) was used to characterize surface topography prior to wear testing. Wear resistance was evaluated using a ball-on-plane tribometer under simulated prosthetic motion, applying a 5 N load with a bone pin as the counter body. Corrosion resistance was assessed through electrochemical impedance spectroscopy (EIS) in a physiological solution. Additionally, tribocorrosive performance was investigated by coupling tribological and electrochemical tests in Ringer’s lactate solution, simulating dynamic in vivo contact conditions. The results demonstrate that Ag doping, combined with increased oxygen content in the sputtering atmosphere, significantly improves both wear and corrosion resistance. Notably, the ZrO₂-Ag coating deposited with 50% O₂ exhibited the lowest wear volume (0.086 mm³) and a minimum coefficient of friction (0.0043) under a 5 N load. This same coating also displayed superior electrochemical performance, with the highest charge transfer resistance (38.83 kΩ·cm²) and the lowest corrosion current density (3.32 × 10⁻⁸ A/cm²). These findings confirm the high structural integrity and outstanding tribocorrosive behavior of the coating, highlighting its potential for application in biomedical implant technology. Full article

Background/Objectives: Knee osteoarthritis is one of the most significant diseases globally and in Portugal. Despite the availability of international guidelines, there is a lack of tailored, evidence-based recommendations specifically for Portuguese physiotherapists to manage their knee osteoarthritis patients with non-pharmacological and non-surgical interventions. This study aimed to develop a clinical practice guideline that integrates the latest international evidence with local clinical practice data to enhance patient outcomes. Methods: To achieve the objective, a comprehensive search was conducted in November 2024 across major health-related databases, to identify robust and recent evidence regarding the efficacy of non-pharmacological and non-surgical interventions, as well as their usage in the national context. Two key sources were identified: An umbrella and a mixed-methods study. Data from both sources were independently reviewed and integrated through a comparative analysis to identify interventions with robust scientific support and high local acceptability. Recommendations were then formulated and categorized into gold (strong), silver (moderate), and bronze (weak) levels based on evidence quality and clinical relevance. A decision-making flowchart was developed to support guideline implementation and clinical usage. Results: The integrated analysis identified three gold-level interventions, namely Nutrition/Weight Loss, Resistance Exercise, and Self-care/Education. Five silver-level recommendations were Aerobic Exercise, Balneology/Spa, Extracorporeal Shockwave Therapy, Electrical Stimulation, and Manual Therapy. Similarly, five bronze-level recommendations comprised Kinesio Taping, Stretching, Ultrasound Therapy, Thermal Agents, and Walking Aids. Conclusions: This clinical practice guideline provides a context-specific, evidence-based framework for Portuguese physiotherapists managing knee osteoarthritis. By bridging international evidence with local clinical practice, the guideline aims to facilitate optimal patient care and inform future research and guideline updates. Full article

The Qiubudong silver deposit on the western margin of the Fuping ore cluster in the central North China Craton is a representative breccia-type deposit characterized by relatively high-grade ores, thick mineralized zones, and extensive alteration, indicating considerable potential for economic resource development and further exploration. Previous studies on this deposit have not addressed its genetic mineralogical characteristics. This study focuses on pyrite and quartz to investigate their typomorphic features, such as crystal morphology, trace element composition, thermoelectric properties, and luminescence characteristics, and their implications for ore-forming processes. Pyrite crystals are predominantly cubic in early stages, while pentagonal dodecahedral and cubic–dodecahedral combinations peak during the main mineralization stage. The pyrite is sulfur-deficient and iron-rich, enriched in Au, and relatively high in Ag, Cu, Pb, and Bi contents during the main ore-forming stage. Rare earth element (REE) concentrations are low, with weak LREE-HREE fractionation and a strong negative Eu anomaly. The thermoelectric coefficient of pyrite ranges from −328.9 to +335.6 μV/°C, with a mean of +197.63 μV/°C; P-type conduction dominates, with an occurrence rate of 58%–100% and an average of 88.78%. A weak–low temperature and a strong–high temperature peak characterize quartz thermoluminescence during the main mineralization stage. Fluid inclusions in quartz include liquid-rich, vapor-rich, and two-phase types, with salinities ranging from 10.11% to 12.62% NaCl equiv. (average 11.16%) and densities from 0.91 to 0.95 g/cm³ (average 0.90 g/cm³). The ore-forming fluids are interpreted as F-rich, low-salinity, low-density hydrothermal fluids of volcanic origin at medium–low temperatures. The abundance of pentagonal dodecahedral pyrite, low Co/Ni ratios, high Cu contents, and complex quartz thermoluminescence signatures are key mineralogical indicators for deep prospecting. Combined with thermoelectric data and morphological analysis, the depth interval around 800 m between drill holes ZK3204 and ZK3201 has high mineralization potential. This study fills a research gap on the genetic mineralogy of the Qiubudong deposit and provides a scientific basis for deep exploration. Full article

This study explores the development and optimization of TiO₂-based photoactive coatings enhanced with silver (Ag)—to boost photocatalytic performance—for application on glass-fiber-reinforced polyester (GFRP) and epoxy (GFRE) composites. The influence of Ag content on the structural, physicochemical, and functional properties of the coatings was evaluated. The TiO₂-Ag coating showed the best performance and was tested under UV-A irradiation and visible light (Vis), with high efficiency in VOC degradation, self-cleaning, and microbial activity. The tests were repeated in multiple runs, showing high reproducibility in the results obtained. In GFRP, pollutant and microorganism removal ratios of more than 90% were observed. In contrast, GFRE showed a lower adhesion and stability of the coating. This result is attributed to incompatibility problems with the epoxy matrix, which significantly limited its functional performance. The results highlight the feasibility of using the TiO₂-Ag coating on GFRP substrates, even under visible light. Under real-world conditions for 351 days, the coating on GFRP maintained its stability. This type of material has high potential for application in modular building systems using sandwich panels, as well as in facades and automotive components, where self-cleaning and contaminant-control properties are essential. Full article

Marine algae offer environmentally friendly platforms for green nanoparticle synthesis. This study reports the biosynthesis of silver nanoparticles using polysaccharides isolated from the brown alga Chnoospora minima (PAgNPs) and evaluates their therapeutic potential. Fourier Transform Infrared Spectroscopy (FTIR) confirmed algal polysaccharide functional groups. Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis characterized the nanoparticles as spherical (~84 nm average size), stable (zeta potential −18.5 mV), and containing elemental silver without nitrogen. The PAgNPs exhibited potent antioxidant activity (~100% DPPH scavenging) and significant antimicrobial efficacy, particularly against Staphylococcus aureus and Candida species. Crucially, PAgNPs displayed potent antiproliferative activity against human lung cancer cells (A549, IC₅₀: 13.59 µg/mL). In contrast, toxicity to normal Vero cells was significantly lower (IC₅₀: 300.2 µg/mL), demonstrating notable cancer cell selectivity (SI 22.1). Moderate activity was observed against MCF-7 breast cancer cells (IC₅₀: 100.7 µg/mL). These results demonstrate that C. minima polysaccharide facilitates the synthesis of biocompatible AgNPs with promising antimicrobial and selective anticancer capabilities, highlighting their potential for further development as nanotherapeutics. Full article

This study investigates the antioxidant, antimicrobial, and antitumor activities of Taraxacum officinale (Dandelion) and Artemisia annua (Sweet Wormwood) extracts, along with their role in the green synthesis of gold (AuNPs) and silver nanoparticles (AgNPs). Bioreduction was achieved using aqueous and ethanolic extracts (100 mg/mL), enabling solvent-dependent comparisons. Nanoparticles were characterized using ultraviolet–visible spectroscopy (UV–Vis), fluorescence spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Each technique revealed complementary aspects of nanoparticle morphology, size, and stability, with UV–Vis indicating aggregation states and DLS confirming solvent-related size variation even at 3–5% ethanol. Gold nanoparticles synthesized from Dandelion showed strong antibacterial activity against Staphylococcus aureus, while silver nanoparticles from both plants were effective against Escherichia coli. Cytotoxicity assays indicated that silver nanoparticles obtained from ethanolic Dandelion extract containing 3% ethanol in aqueous solution (AgNPsE_ETOH3%-D) significantly reduced LoVo (p = 4.58 × 10⁻³) and MDA-MB-231 (p = 7.20 × 10⁻⁵) cell viability, with high selectivity indices (SI), suggesting low toxicity toward normal cells. Gold nanoparticles synthesized from aqueous Dandelion extract (AuNPsEaq-D) also showed favorable SI values (2.16 for LoVo and 8.41 for MDA-MB-231). Although some formulations demonstrated lower selectivity (SI < 1.5), the findings support the therapeutic potential of these biogenic nanoparticles. Further in vivo studies and pharmacokinetic evaluations are required to validate their clinical applicability. Full article