Search Results (558)

Graphitic carbon nitride (g-C₃N₄), an emerging metal-free semiconductor material, has attracted considerable attention in the field of photoelectrochemical (PEC) sensing due to its unique electronic structure, excellent chemical stability, and visible-light responsiveness. This article systematically reviews recent advances in research on g-C₃N₄-based PEC sensors applied to water environment monitoring. First, the fundamental physicochemical properties of g-C₃N₄ are introduced, along with its advantages and limitations in PEC sensing applications. Subsequently, four main performance enhancement strategies are outlined: heterojunction construction (including type II, Z-scheme, and S-scheme heterojunction), elemental doping and defect engineering, morphology control and nanostructure design, as well as various signal amplification approaches such as self-powered systems, dual-mode detection, and cyclic amplification. Furthermore, the current application status of these sensors in detecting typical water pollutants, including heavy metal ions (e.g., Pb²⁺, Cu²⁺, Cd²⁺, Hg²⁺), antibiotics (e.g., tobramycin, norfloxacin, kanamycin), pesticide residues (e.g., chlorpyrifos, atrazine, glyphosate), and pathogenic microorganisms (e.g., Salmonella, Candida albicans), is comprehensively reviewed, with particular emphasis on detection sensitivity, selectivity, and real-sample performance. Finally, the remaining challenges in terms of long-term stability, anti-interference capabilities in complex matrices, portability, and multifunctional integration are analyzed, and future development directions are proposed, including smartphone-based intelligent sensing, CRISPR/Cas12a-assisted signal amplification, and multi-target high-throughput detection. This review aims to provide a reference for the rational design and practical application of g-C₃N₄-based PEC sensors in the field of water environment monitoring. Full article

Yttrium doping has been reported to be an effective approach to enhance the mechanical and protective properties of ZrN coatings by magnetron sputtering. Nitrogen (N₂) flow ratio during reactive magnetron sputtering is known to critically influence the stoichiometry, defect structure, and microstructure of nitride coatings. However, its systematic effect on Y-doped ZrN (ZrYN) coatings has remained unexplored. In this work, ZrYN coatings with a fixed Y content were deposited by reactive magnetron sputtering under varying N₂ flow ratios (0–10%). Their microstructure, mechanical properties, corrosion resistance in 3.5 wt% NaCl solution, and oxidation behavior at 650 °C were systematically investigated. Below 5% N₂ flow ratio, the coatings are metallic ZrY, showing very low hardness, poor corrosion resistance, and catastrophic oxidation failure. At N₂ flow ratio ≥ 5%, cubic ZrYN forms, with stoichiometry varying from sub-stoichiometric (5%) to near-stoichiometric (7.5%) to over-stoichiometric (10%). The near-stoichiometric coating at 7.5% exhibits the finest columnar grains and densest microstructure, leading to the highest hardness (32.2 ± 1.4 GPa) and an elastic modulus of (469.6 ± 24.5 GPa), as well as the best corrosion resistance (two orders of magnitude lower than bare 316 stainless steel). Upon oxidation, it forms a thin and dense epitaxial t-ZrO₂ scale stabilized by Y₂O₃, suppressing the destructive tetragonal to monoclinic transformation. Off-stoichiometric coatings at 5% and 10% develop thicker, cracked oxide scales and show inferior properties. Precise control of N₂ flow ratio is therefore essential to achieve a near-stoichiometric ZrYN coating with superior mechanical, anti-corrosion, and anti-oxidation performance. Full article

Chitosan-based copper composites have attracted considerable interest for biomedical and antimicrobial uses due to their biocompatibility, adjustable dielectric characteristics, and ion-mediated antimicrobial effectiveness. In this study, chitosan films doped with Cu(NO₃)₂, containing 3, 6, and 9 wt% of copper nitrate were produced using a solution-casting method at room temperature. This was done to explore the relationship between structural interactions, dielectric relaxation, optical properties, and antimicrobial efficacy. The resulting composite has been investigated physically using FTIR, XRD, optical analysis, and dielectric spectroscopy, and biologically for its antimicrobial activity. FTIR revealed the molecular structure of Cs-Cu(NO₃)₂ and changes resulting from new bond(s) formation and/or decomposition. XRD indicated that there are no peaks assigned for CuO, which weakens the composite antimicrobial activity. Optical analysis showed an increase in the band gap with copper (II) nitrate concentration over 3%. Additionally, the electrical impedance of the resulting composite increased by approximately one decade. A detailed electrical analysis of the charge-carrier types is provided. Moreover, the antimicrobial activity of chitosan is slightly enhanced by the additive copper (II) nitrate in a dose-dependent manner. The current research offers a mechanistic understanding of the structure–property relationships that govern the behavior of Cu(NO₃)₂–chitosan composites, emphasizing the significant influence of processing conditions on adapting of their dielectric and biological properties. Full article

The performance requirements of wear-resistant and anti-corrosion coatings for marine equipment continue to increase. Diamond-like carbon (DLC) film has become a preferred protective material due to its high hardness, low friction and chemical inertia. To reveal the tribocorrosion mechanism of Si-doped DLC films in a seawater environment, a Cr-WC-WC/C transition layer and DLC-Si films with different Si contents were prepared by high-power pulsed magnetron sputtering (HiPIMS) technology on 304 stainless steel. The tribocorrosion tests were carried out under open-circuit potential and dynamic polarization conditions in seawater. The results show that Si doping improved the tribocorrosion resistance of the films. The sample with Si content of 9.26 at.% has the lowest self-corrosion current density, the smallest volume loss, complete wear scar morphology and no obvious substrate exposure. The strengthening mechanism is attributed to Si doping, which induces the formation of a SiO_x passivation film and a hydrated silica gel lubrication layer. This establishes a synergistic solid-chemical lubrication system, inhibits sp² cluster growth, prolongs the diffusion path of corrosive media, and mitigates the damaging wear–corrosion synergy. This study confirms that moderate Si doping can significantly improve the wear resistance and corrosion resistance of DLC films in a seawater environment, and provides a theoretical basis for the design and application of carbon-based protective coatings for marine equipment. Full article

Ecdysterone is a natural compound proposed as an alternative to anabolic-androgenic steroids (AAS) due to its comparable ergogenic potential and more favorable safety profile. This narrative review summarizes current evidence using a standardized search protocol. Although many plants synthesize ecdysteroids, only a few cultivated species—emphasizing quinoa and spinach—contribute meaningfully to dietary intake, while wild species such as those from the Ajuga genus contain substantially higher concentrations. Experimental studies indicate that ecdysterone enhances protein synthesis and physical performance through estrogen receptor-beta activation, avoiding the adverse effects typically associated with AAS. Additional pharmacological effects, including potential roles in breast cancer therapy and Alzheimer’s disease, have also been described. Ecdysteroids are generally considered non-toxic in humans; however, analysis of commercial supplements frequently reveals poor quality control and discrepancies between labeled and actual ecdysterone content. Although prevalence of use among athletes appears low, establishing urinary reference ranges to differentiate dietary exposure from supplement-derived intake is essential. Ecdysterone and its metabolites, 14-deoxy-ecdisterone and 14-deoxy-poststerone, are detectable in urine for more than two days depending on dosage. Given its ergogenic potential and detectability, ecdysterone may pose risks for unethical use and should be considered for inclusion in initial anti-doping testing procedures. Further research on ecdysteroids is required to elucidate their mechanisms of action, confirm the absence of adverse effects, and establish reference urinary concentration ranges that allow differentiation between diet-related metabolites and those derived from drug use. Full article

This study provides a comprehensive evaluation of the phytochemical composition, antioxidant capacity, antibacterial activity, and mineral content of Trigonella foenum-graecum, Linum usitatissimum, and Panicum miliaceum extracts obtained using aqueous, ethanolic, and methanolic solvents. An integrated analytical strategy combining LC–MS/MS-based metabolite profiling, mineral analysis, and multivariate statistical tools (PCA) was applied to investigate the relationships between chemical composition and biological activities. The ethanolic extract of P. miliaceum showed the highest total phenolic content (TPC: 157.438 ± 0.521 µg GAE/mg extract), whereas L. usitatissimum exhibited the strongest antioxidant activity (IC₅₀ ≈ 65 µg/mL). Trigonella foenum-graecum displayed the most significant antibacterial activity, with a minimum inhibitory concentration (MIC) of 62.5 mg/mL against Staphylococcus aureus. LC–MS/MS analysis allowed the identification and structural characterization of more than twenty bioactive compounds through multiple reaction monitoring (MRM), including flavonoids, phenolic acids, and anthocyanins. Principal Component Analysis indicated that sample discrimination was mainly driven by solvent polarity rather than plant species, underlining the critical influence of extraction conditions on phytochemical profiles and associated bioactivities. These findings highlight the relevance of combining analytical and statistical approaches to better understand the interplay between plant origin, extraction conditions, and biological properties, and support the potential of these species as promising sources of nutraceutical and pharmaceutical compounds. Full article

Doping remains a major threat to athlete health and sport integrity. Although anti-doping efforts have traditionally focused on athletes, increasing attention has turned to Athlete Support Personnel (ASP) due to their influence on athletes’ decisions, behaviors and involvement in anti-doping rule violations. This narrative review aimed to synthesize the existing literature on the role of ASP (including coaches, physicians, pharmacists, sport psychologists, nutritionists, physiotherapists, parents and other family members) in anti-doping, with particular attention to their influence on athletes’ knowledge, attitudes, behaviors, education and decision-making related to doping. Coaches, physicians, and pharmacists are among the ASP groups most frequently examined in the literature, although substantial knowledge gaps remain across all groups. Coaches shape motivational climates and ethical norms but often lack adequate understanding of anti-doping regulations and supplement risks. Physicians and pharmacists play key roles in medication management and Therapeutic Use Exemptions procedures, though incomplete regulatory knowledge may contribute to inadvertent violations. Nutritionists are central in preventing supplement-related doping, while research on sport psychologists and physiotherapists remains limited despite their preventive potential. Parents significantly shape athletes’ moral development and susceptibility to doping, acting as protective or risk factors depending on family dynamics. Overall, anti-doping education for ASP remains inconsistent. In conclusion, ASP plays an essential yet heterogeneous role in influencing doping-related behaviors. Strengthening role-specific and interdisciplinary anti-doping education, particularly within university programs and professional development, appears critical for enhancing ASP competence and promoting a sustainable culture of clean sport. Full article

Developing an ultrasensitive electrochemiluminescence (ECL) detection platform remains challenging due to the limited enrichment efficiency of ECL emitters and co-reactants at the electrode interface, as well as the insufficient catalytic enhancement of co-reactant conversion. Moreover, simultaneous in situ analyte enrichment and efficient anti-interference capability are often difficult to achieve in a single sensing interface. Herein, a new ECL platform was developed based on nanocatalyst-supported nanochannel-confined surfactant micelle (SM) system, which integrates an enhanced luminol-dissolved oxygen (DO) ECL response for the ultrasensitive detection of antibiotic rifampicin (RIF). A nanocomposite comprising nitrogen-doped graphene quantum dots and a molybdenum disulfide nanosheet (NGQDs@MoS₂) was modified on an indium tin oxide (ITO) electrode. This nanocomposite layer catalyzed the oxygen reduction reaction (ORR), boosting the co-reactant efficiency of DO. Vertically ordered mesoporous silica film filled with surfactant micelles (SM@VMSF) was subsequently grown in situ on the NGQDs@MoS₂ surface. The hydrophobic micelles enable the simultaneous enrichment of luminol, DO, and RIF. Integrating the triple-enrichment effect of surfactant micelles with the high electrocatalytic effect of NGQDs@MoS₂ nanocomposite results in significant ECL enhancement of the luminol–DO. SM@VMSF also provides an excellent molecular sieving effect, endowing the sensor with high anti-interference capability and stability. RIF quenches the ECL signal by consuming superoxide anion radicals, enabling sensitive detection. Detection of RIF was established with a high sensitivity (2927 a.u. per nM) wide linear range (10 pM to 10 μM) and a low limit of detection (LOD, 2.5 pM). The fabricated sensor exhibits good selectivity and high fabrication reproducibility (relative standard deviation, RSD, of 1.9%). Additionally, the determination of RIF in eye drops and seawater samples was realized. This work offers new insights for the design of high-performance ECL sensing interfaces and sensitive detection of RIF. Full article

Upper airway function has received limited attention as a potentially relevant component of respiratory physiology in aquatic athletes. Repeated exposure to chlorinated indoor environments, combined with high ventilatory demand during training, may contribute to the development of chronic irritant rhinitis characterized by nasal obstruction and mucosal hyperreactivity. Although often perceived as a minor inconvenience, increased nasal resistance may influence breathing comfort, perceived exertion, and recovery stability in swimmers and other aquatic athletes. In addition to environmental exposure, the widespread use of topical nasal decongestants may result in rebound congestion and rhinitis medicamentosa, thereby contributing to a self-reinforcing cycle of airway dysfunction. Performance-related pressure and uncertainty related to anti-doping regulations may further shape medication behavior within athletic environments. This narrative review integrates environmental exposure mechanisms, mucosal pathophysiology, and behavioral medication patterns to provide a unified conceptual framework for understanding upper airway dysfunction in aquatic athletes. Particular emphasis is placed on nasal airflow stability as a potentially relevant factor in breathing comfort, sleep quality, and training consistency. Given that the available evidence is predominantly mechanistic and observational, the proposed relationships should be interpreted as hypothesis-generating and translational rather than as evidence of direct causal effects on athletic performance. Full article

Photo-Fenton technology is considered an effective method for removing organic pollutants from water. In this work, a novel Mn-doped FeWO₄ (Mn-FeWO₄) photocatalyst was synthesized via a one-step hydrothermal method and applied for the photo-Fenton degradation of tetracycline (TC). The optimal Mn-FeWO₄-0.05 achieved 100% removal of TC within 60 min under visible light irradiation with a degradation rate constant of 0.0793 min⁻¹, which is 4.5 times higher than that of pristine FeWO₄. Systematic characterization revealed that Mn²⁺ ions were successfully incorporated into the FeWO₄ lattice, inducing lattice expansion and narrowing the bandgap from 2.37 eV to 2.25 eV, while also adjusting the conduction and valence band positions. This modulation significantly enhanced visible light absorption and promoted the separation and migration of photogenerated electron–hole pairs. In addition, the Mn²⁺/Mn³⁺ and Fe²⁺/Fe³⁺ dual redox cycles ensure the continuous generation of reactive oxygen species. Radical trapping experiments and electron paramagnetic resonance (EPR) spectroscopy demonstrated that superoxide radicals (•O₂⁻) and photogenerated holes (h⁺) were the dominant reactive species, while singlet oxygen (¹O₂) and hydroxyl radicals (•OH) played auxiliary roles. Moreover, Mn-FeWO₄-0.05 exhibited excellent stability, strong anti-interference ability against common anions, and high degradation efficiency toward various pollutants. Full article

Phytoecdysteroids have garnered increasing interest due to their broad biological and pharmacological properties. The present study reports on the development and validation of a reliable liquid chromatography–mass spectrometry method for the detection and quantification of 20-hydroxyecdysone, turkesterone, and ponasterone. The optimized procedure improved ionization efficiency and chromatographic resolution through gradient elution using 0.1% formic acid in water and acetonitrile. Data acquisition in selective ion monitoring modes ensured high analytical precision, reproducibility, and sensitivity. The method demonstrated excellent linearity, accuracy, repeatability, and low detection limits, making it suitable for routine phytochemical and quality control applications. Application of the method to extracts from nutrient-rich superfoods, including kaniwa, spinach, quinoa, and asparagus, confirmed these plants as natural sources of phytoecdysteroids. Additionally, thirteen commercially available dietary supplements labeled as containing extracts of Rhaponticum carthamoides, Cyanotis arachnoidea, Ajuga turkestanica, or ecdysteroids were analyzed. Several products standardized to 80–95% ecdysterone contained substantially lower amounts than declared, with measured 20-hydroxyecdysone levels ranging from below the limit of detection to approximately 50 mg per capsule, whereas some non-standardized products exhibited moderate to high levels, reaching up to approximately 105 mg per capsule. Variability in turkesterone content was also observed among products marketed as standardized extracts. The method provides a simple, reliable, and accessible approach for the quantitative analysis of major phytoecdysteroids in complex plant matrices and dietary supplements. Its implementation may support phytochemical research, routine quality control, and anti-doping monitoring of ecdysteroid-containing products. Full article

Background: The incremental model of doping behavior (IMDB) posits that doping develops over time through the habit of using performance enhancers such as dietary supplements. We investigated the association between dietary supplement use and beliefs and doping attitudes among Norwegian sportspersons. Methods: A total of 1441 subjects (females: 44%; age 31.3 ± 11.6 years) responded to an online questionnaire including measures of dietary supplement use and beliefs, performance enhancement attitude (PEAS), and a doping likelihood vignette. Data were analyzed using descriptive statistics, correlations, and multiple regression analysis. Results: 58% used dietary supplements. Dietary supplement beliefs were positively correlated with doping attitudes (r = 0.27 (PEAS) and r = 0.16 (vignette), p < 0.001). Among non-competitive respondents, younger respondents were more likely to endorse supplement use (r = −0.08, p = 0.073 vs. r = −0.30, p < 0.001) and doping use (r = −0.17, p < 0.001 and r = −0.21, p < 0.001). Males endorsed supplement use (Welch’s t tests > 5.19, p < 0.001) and doping (Welch’s t tests > 4.08, p < 0.001) more than females. Norwegian sportspersons are generally ambivalent about dietary supplements but opposed to doping practices in sport. Results of multiple regression analysis indicated that younger, male, non-competitive, and supplement-endorsing participants were more likely to endorse doping likelihood. However, these differences were small, and participants were generally against doping. Conclusions: The associations between dietary supplement use and beliefs and doping attitudes are weak but compatible with the IMDB. The differences between groups are small; however, focusing on beliefs about dietary supplements in young, male, non-competitive persons may improve the effectiveness of anti-doping interventions. Full article

Background/Objectives: Nanostructured biomaterials based on natural polymers have gained increasing attention in pharmaceutics due to their biocompatibility, multifunctionality, and diverse biomedical applications. This novel study aimed to biofabricate chitosan-doped zinc oxide nanocomposites (CS-ZnONCs) using Leucas aspera leaf extract and to evaluate their physicochemical properties and in vitro biomedical performance. Methods: CS-ZnONCs were synthesized using L. aspera leaf extract through a green precipitation approach, and the resulting nanocomposites were characterized by various spectroscopic techniques. The in vitro antioxidant, antibacterial, and anti-inflammatory activities were evaluated, while wound-healing potential was assessed using L929 fibroblast cell migration assays. Results: UV–visible analysis confirmed the formation of CS-ZnONCs, with a characteristic absorption peak at 362 nm, and FTIR spectra indicated the presence of various important functional groups. XRD results demonstrated the crystalline nature of ZnO within the chitosan matrix. Well-dispersed, quasi-spherical nanoparticles with an average size of 44 ± 3.1 nm were identified by HR-TEM, and a positive zeta potential (+9 mV) suggested considerable colloidal stability. CS-ZnONCs showed a high swelling capacity (88 ± 2.75% for 2%) and significant phytocompound release (65.38 ± 2.79% at pH 7.4). The CS-ZnONCs showed significant antioxidant activity (ABTS of 88.19 ± 1.59%), notable antibacterial efficacy against Staphylococcus aureus (18.78 ± 0.98 mm) and Escherichia coli (17.14 ± 0.96 mm), and significant anti-inflammatory activity (82.12 ± 1.47% membrane stabilization). In vitro biocompatibility and wound-healing assays revealed significant cytocompatibility in Vero cells, with 98.75 ± 1.17% cell viability observed, whereas the fibroblast migration assay demonstrated near-complete wound closure (96.55 ± 6.46%). Conclusions: The green-synthesized CS-ZnONCs exhibit favorable physicochemical properties, biocompatibility, and multifunctional biological activities, supporting their potential as a promising sustainable biomaterial nanomedicine for pharmaceutical formulations, wound healing, and regenerative medicine applications. Full article

Dopamine (DA) plays an extremely crucial role in the metabolic processes of the human body. Accurate detection of DA is of great significance for many major diseases. This study reports an innovative synthesis method for composite material in which sulfur (S) and nitrogen (N) are incorporated into multi-walled carbon nanotubes (MWCNTs), and platinum (Pt) nanoparticle sensors (Pt/CNTs-N-S) are loaded for the highly sensitive and selective electrochemical detection of DA. The linear range of this sensor is from 0.0078 to 2 mM, and the limit of detection (LOD) is 0.73 μM (S/N = 3) for DA detection. The outstanding detection performance exhibited by Pt/CNTs-N-S is mainly attributed to the co-doping of N and S, which improves the surface properties of MWCNTs, and the dispersion of Pt nanoparticles (5.22 nm), which significantly increases the electrochemically active surface area (ESCA). In addition, the Pt/CNTs-N-S sensor also exhibits excellent stability and anti-interference performance. Overall, this study provides a simple and practical strategy for the potential application of Pt-based sensors in the detection of DA. Full article

Steroid hormones exert diverse and tissue-specific biological effects despite sharing a conserved tetracyclic scaffold. Among these, anabolic–androgenic steroids (AAS) present a longstanding paradox: structurally related compounds can elicit markedly different anabolic, androgenic, and cardiovascular outcomes. This narrative review integrates advances in steroid structural chemistry, androgen receptor (AR) biology, and intracellular signaling to elucidate the molecular mechanisms underlying anabolic–androgenic dissociation. We summarize classical genomic and emerging non-genomic modes of steroid action, emphasizing how receptor conformation, ligand-binding domain architecture, co-regulator recruitment, and signaling bias shape downstream biological responses. Particular focus is placed on the structure–activity relationships of endogenous and synthetic androgens, with C17-substitution chemistry highlighted as a central determinant of receptor affinity, metabolic stability, pharmacokinetics, and tissue selectivity. By linking molecular structure to receptor-level mechanisms, we contextualize the physiological and pathophysiological effects of major AAS classes used clinically and non-medically, including testosterone esters, 19-nor derivatives, 17α-alkylated steroids, heterocyclic compounds, and halogenated compounds. While much of the mechanistic evidence derives from preclinical models, the integrated framework presented here provides a coherent basis for interpreting divergent anabolic, androgenic, and cardiovascular effects observed in humans. Collectively, this review bridges fundamental steroid biology with applied physiology and sports medicine, offering mechanistic insight relevant to therapeutic development, anti-doping science, and risk assessment of supraphysiological androgen exposure. Full article