Search Results (1,115)

Background: Root canal sealers may come into direct contact with periapical tissues, particularly in cases of apical extrusion, potentially influencing periapical healing and treatment outcomes. Cytotoxicity assessment represents a clinically relevant parameter when selecting endodontic sealers. However, evidence derived from in vitro studies remains heterogeneous and challenging to interpret from a clinical perspective. Therefore, the aim of this systematic review was to critically evaluate the in vitro cytotoxicity of all root canal sealers that have been commercially marketed over the years, excluding experimental materials, and to contextualize the findings in relation to clinically relevant experimental conditions. Methods: This systematic review was conducted according to PRISMA guidelines and preregistered on the Open Science Framework. PubMed, Scopus, and the Cochrane Library were searched up to 30 November 2025. In vitro studies evaluating the cytotoxicity of commercially available root canal sealers using validated cell viability or proliferation assays were included. Data extraction focused on sealer composition, setting condition, extraction protocols, exposure parameters, and cytotoxic outcomes. Due to marked methodological heterogeneity, a qualitative synthesis was performed. Results: Ninety-eight in vitro studies were included. All categories of root canal sealers demonstrated some degree of cytotoxicity, particularly when tested in freshly mixed conditions, at higher extract concentrations, or after prolonged exposure. Bioactive and calcium silicate-based sealers generally showed a more favorable cytotoxicity profile compared with conventional materials, especially after complete setting and at diluted concentrations, although cytotoxic effects were reported under specific experimental conditions. Resin-based sealers, including AH Plus, exhibited condition-dependent cytotoxicity, while zinc oxide–eugenol and glass ionomer sealers tended to display higher cytotoxic potential. Conclusions: In vitro cytotoxicity of root canal sealers varies according to material composition and experimental conditions. Bioactive sealers generally exhibit a more favorable biological profile, which may be clinically relevant in situations involving sealer extrusion or prolonged tissue contact. Standardized testing protocols and further translational studies are required to support evidence-based clinical material selection. Full article

Zinc (Zn) in excess is very toxic for plants and can limit agriculture. Carbon-based engineered nanomaterials with high electron mobility and electron-accepting capability may be essential for mitigating heavy metal stress. In the present study, the protective role of some fullerene C₆₀ derivatives (fullerenol [C₆₀(OH)_22–24] and the arginine C₆₀ [C₆₀(C₆H₁₃N₄O₂)₈H₈]) were tested for the first time against Zn toxicity in Cucumis sativus L. (cucumber). Plants were grown hydroponically at three concentrations of fullerenes (0, 2, and 10 mg L⁻¹) without or with 40 µM Zn for 17 days. Plant growth, leaf chlorosis, and nutritional imbalances in combination with a metabolomics approach were analyzed. The Zn-treated plants show chlorotic leaves, the retarded growth of shoots (−20%), and roots (−49%) and nutrient imbalance. Addition of fullerene C₆₀ derivatives suppressed loss in the dry biomass of leaves (15%) and roots (40%; fullerenol only) induced by high Zn. However, they did not alter leaf chlorophyll, shoot dry biomass, and elemental composition, including leaf Zn. Moreover, the Zn of xylem sup from roots remained unchanged by fullerenes. In an adsorption experiment, the amounts of Zn adsorbed by tested C₆₀ were below the detection limits. The addition of C₆₀ derivatives slightly changed the metabolite profiling in stressed plants. Nevertheless, in fullerene-treated plants, the abundance of some Zn-responsible metabolites tended to be altered in the opposite direction as compared with the metabolic responses to excessive Zn alone. There were several up-regulated metabolites protecting plants under oxidative stress. We speculate that fullerene C₆₀ derivatives have the ability to increase antioxidant non-enzyme activity at least, improving some growth parameters. However, fullerenes did not reduce Zn transport from the root to the shoots. We concluded that the low capacity of these compounds to buffer Zn in the root zone might limit the efficiency of fullerene derivatives against Zn toxicity. Our results provide new evidence for the crucial role of Zn–fullerene interactions in the amelioration of Zn toxicity in plants. Full article

Transition metal (TM)-doped zinc oxide (ZnO) and zirconium dioxide (ZrO₂) nanocrystals exhibit complex correlations between crystal structure, defect chemistry, vibrational properties, and magnetic behavior that are strongly governed by synthesis route and dopant incorporation mechanisms. This review critically summarizes recent progress on Fe-, Mn-, and Co-doped ZnO and ZrO₂ nanocrystals synthesized by wet chemical, hydrothermal, and microwave-assisted hydrothermal methods, with emphasis on synthesis-driven phase evolution and apparent solubility limits. ZnO and ZrO₂ are treated as complementary host lattices: ZnO is a semiconducting, piezoelectric oxide with narrow solubility limits for most 3d dopants, while ZrO₂ is a dielectric, polymorphic oxide in which transition metal doping may stabilize tetragonal or cubic phases. Structural and microstructural studies using X-ray diffraction, electron microscopy, Raman spectroscopy, and Mössbauer spectroscopy demonstrate that at low dopant concentrations, TM ions may be partially incorporated into the host lattice, giving rise to diluted or defect-mediated magnetic behavior. When solubility limits are exceeded, nanoscopic secondary oxide phases emerge, leading to superparamagnetic, ferrimagnetic, or spin-glass-like responses. Magnetic measurements, including DC magnetization and AC susceptibility, reveal a continuous evolution from paramagnetism in lightly doped samples to dynamic magnetic states characteristic of nanoscale magnetic entities. Vibrational spectroscopy highlights phonon confinement, surface optical phonons, and disorder-activated modes that sensitively reflect nanocrystal size, lattice strain, and defect populations, and often correlate with magnetic dynamics. Rather than classifying these materials as diluted magnetic semiconductors, this review adopts a synthesis-driven and correlation-based framework that links dopant incorporation, local structural disorder, vibrational fingerprints, and magnetic response. By emphasizing multi-technique characterization strategies required to distinguish intrinsic from extrinsic magnetic contributions, this review provides practical guidelines for interpreting magnetism in TM-doped oxide nanocrystals and outlines implications for applications in photocatalysis, sensing, biomedicine, and electromagnetic interference (EMI) shielding. Full article

One of the main obstacles to producing natural rubber-modified asphalt is the difficulty of mixing Technical Specification Natural Rubber (TSNR) or its compounds with asphalt, leading to long mixing times and high costs. This study aims to evaluate the use of 60/70 penetration asphalt as a plasticizer to accelerate the mixing process and improve the rheological properties of modified asphalt using Technical Specification Natural Rubber (TSNR). The production process for technical specification natural rubber-modified asphalt involves two stages: the production of the technical specification natural rubber compound (CTSNR) and the production of CTSNR-based modified asphalt (CTSNRMA). The CTSNR production process begins with mastication of technical specification natural rubber (TSNR), followed by the addition of activators (zinc oxide, stearic acid), accelerators (Mercaptobenzothiazole sulfenamide (MBTS)), antioxidants (2,2,4-Trimethyl-1,2-dihydroquinoline (TMQ)), and 60/70 penetration asphalt as a plasticizer (at concentrations of 30%, 40%, and 50%). After homogeneous mixing for 30–60 min, the CTSNR is diluted 5–10 mm for the next mixing stage with hot asphalt at 160–170 °C. The best results of this study showed that CTSNR-modified asphalt with 4% rubber content and 50% plasticizer (CTSNRM-450) successfully reduced the mixing time to 16 min, making it more efficient than the traditional method, which takes up to 180 min. The addition of asphalt plasticizer decreased penetration to 35.6 dmm and increased the softening point to 55.4 °C. The CTSNRMA-440 formula, with 4% rubber content and 40% plasticizer, produced the best results in terms of storage stability, meeting the ASTM D5892 standard with a softening-point difference of 0.95 °C, which is well below the threshold of 2.2 °C. The CTSNRMA-440 sample achieved a Performance Grade (PG) of 76, suitable for hot-climate conditions, with a significant reduction in mixing time, greater stability, and increased resistance to high temperatures. Full article

The proper course of pregnancy and fetal development depends, among other factors, on maintaining adequate levels of micronutrients in the maternal body. This integrative, concept-driven narrative review summarizes the current state of knowledge on the impact of selected elements, referred to as oncoelements, on placental function and obstetric outcomes. These include both potentially protective elements (selenium, zinc, copper) and toxic metals (cadmium, lead, arsenic), which, in excess may disrupt oxidative, hormonal, and epigenetic homeostasis. Rather than providing a quantitative synthesis, the article is structured around a four-level conceptual model integrating molecular mechanisms, placental protection, clinical outcomes, and umbilical cord blood as a biomarker of prenatal exposure. Mechanisms of toxicity include oxidative stress, mitochondrial dysfunction, DNA damage, and altered gene expression. Given the observational nature of most studies, clinical recommendations remain cautious. Micronutrient assessment may be useful in selected high-risk groups, but requires further validation. In environmentally burdened regions, screening for toxic metals may be considered. Future research should clarify dose–response relationships, define threshold concentrations, and explore molecular biomarkers of exposure. Umbilical cord blood offers a promising matrix for assessing fetal exposure, although interpretation is limited by methodological variability and the lack of reference values. Full article

Zinc oxide nanoparticles (ZnO NPs) have attracted growing interest in several fields, including topical biomedical applications, due to their stability, biocompatibility and therapeutic potential. In this study, chitosan (Ch), gelatin (G) and arabic gum (AG) were combined to formulate hydrogels loaded with different ZnO NP concentrations. The main aim is to assess the synergy between the properties of biopolymers and ZnO moieties in terms of antiviral activity. ZnO NPs were synthesized via co-precipitation. Hydrogels were prepared using the freeze–thaw method, and the loading of 2.5, 5 and 7.5% w/w of ZnO NPs with respect to Ch was promoted by ultrasonication. The structural, morphological, surface and thermal properties of hydrogels loaded with ZnO NPs (HZ 2.5, HZ 5 and HZ 7.5) and the control matrix (H) were characterized using FTIR spectroscopy, confirming the successful incorporation and interaction of ZnO NPs with the polymeric network. Low ZnO NP concentrations enhanced the swelling degree of the hydrogels (from 1044% to 1253%), improving their thermal stability and solubility (96 h vs. 48 h HZ 7.5 and 14 h in the case of H). This behavior could be ascribed to the aggregation of ZnO NPs with increasing amounts, which was verified through FESEM. Virucidal activity was tested against herpes simplex virus type 1 (HSV-1) and bovine coronavirus (BCoV), demonstrating a substantial enhancement when the ZnO NPs are added independently of the concentration. An almost 100% viral inhibition was recorded when the HZs were analyzed, whereas the H matrix showed an inhibition of about 40% against the same virus. Antioxidant activity was evaluated via the DPPH free radical inhibition method, revealing an improvement with the loading of NPs. Full article

Zinc oxide (ZnO) is a widely studied photocatalyst for the degradation of organic pollutants in water, yet its conventional sol–gel synthesis often suffers from low yield and produces materials with low specific surface area. In this study, we tackled these limitations by synthesizing ZnO nanoparticles using a supercritical-CO₂-assisted sol–gel method (ZnO-scCO₂). The influence of the calcination temperature, precursor concentration, and solvent type on the synthesis of ZnO was systematically investigated, and the materials were characterized with a combination of techniques (XRD, SEM, N₂ physisorption, UV-Vis-DRS spectroscopy). The photocatalytic performance of the ZnO-scCO₂ materials was evaluated in the degradation of two probe pollutants (phenol and rhodamine B, 200 ppm), under UV and visible radiation. The scCO₂-assisted method in ethanol as the solvent allowed achieving at least a four-fold higher ZnO yield and two-fold higher surface area compared to the materials prepared with a conventional sol–gel route without scCO₂. These ZnO-scCO₂ nanoparticles consistently showed enhanced photocatalytic activity in the removal of phenol and rhodamine B compared to their counterparts synthesized without scCO₂ and compared to commercial ZnO. Among the screened synthetic parameters, the solvent in which ZnO was prepared proved to be the one with the strongest influence in determining the ZnO yield and its photocatalytic activity. The optimum results were obtained using 0.50 M zinc acetate as the precursor in 1-butanol as the solvent, and calcination at 300 °C. Full article

Dynamic environmental changes significantly affect trace element balance and exposure to toxic metals, influencing vascular homeostasis. The endothelium, as a key regulator of vascular tone and inflammation, is highly sensitive to fluctuations in micronutrient and heavy metal concentrations. This review summarizes current evidence on the molecular mechanisms by which essential trace elements, such as zinc, selenium, copper, and magnesium, support endothelial function through antioxidant defense, nitric oxide regulation, and anti-inflammatory signaling. Conversely, exposure to heavy metals including cadmium, lead, mercury, and arsenic induces oxidative stress, disrupts nitric oxide bioavailability, and promotes endothelial dysfunction, accelerating the pathogenesis of many diseases. The paper examines how these alterations contribute to the development of major cardiovascular diseases and outlines preventive measures to reduce associated risks. Understanding these interactions is crucial for society’s health amid growing environmental challenges. Full article

Glyphosate is widely used for weed control in coffee but can induce physiological alterations due to its lack of selectivity, and indirect spray drift can cause adverse effects, potentially increasing biological impacts upon exposure. In this study, we evaluated the attenuating effect of foliar-applied zinc oxide nanoparticles (ZnO NPs) on C. arabica var. Geisha seedlings exposed to simulated spray concentrations of glyphosate (3.6 and 17.9 g ae L⁻¹). Exposure caused a marked reduction in chlorophyll content, stomatal conductance, and net photosynthesis, while simultaneously promoting an increase in H₂O₂, MDA, and proline accumulation, reflecting a pronounced redox imbalance and oxidative damage associated with the production of reactive oxygen species (ROS). In contrast, the application of ZnO NPs improved photosynthetic efficiency, increased chlorophyll content, stabilized stomatal aperture, and reduced H₂O₂ and MDA levels in both leaves and roots. Moreover, it enhanced nutrient accumulation, ensuring greater membrane integrity and more efficient ion transport systems under glyphosate exposure. Overall, the ZnO NPs exhibited a notable protective effect by reducing glyphosate-induced phytotoxicity and strengthening the physiological tolerance of C. arabica. These findings support their potential as a sustainable tool to protect coffee crops from glyphosate exposure. Full article

Erosion wear represents a significant issue in piping systems across energy and chemical industries, particularly in elbows. This study develops a prediction model for erosion wear based on tangential and normal impact energy for elbow tubes fabricated from zinc oxide-modified bidirectional E-glass fiber-reinforced epoxy resin composites (ZnO-BE-GFRP). Using a combined CFD-DEM approach, the wear characteristics under gas–solid two-phase flow conditions were systematically investigated. The model quantifies the contributions of tangential and normal impact energy to material removal through the specific energy for cutting wear (e_t) and the specific energy for deformation wear (e_n), with key parameters calibrated against experimental data from ZnO-BE-GFRP. This study shows that the increase in gas velocity significantly intensifies wear, and the wear area extends towards the middle of the elbow as the gas velocity increases. The 40–45° area of the elbow is a high-risk wear zone due to the concentration of particle kinetic energy and high-frequency collisions. The particle size distribution has a significant impact on wear: as the degree of particle dispersion increases, the wear on the elbow extrados decreases. Full article

High-performance piezoelectric poly(vinylidene fluoride) (PVDF) has great application potential in the field of microsensors, but achieving efficient polarization remains a challenge. Here, the in situ doping electrospinning technique is employed to enhance the piezoelectric properties by introducing a single dose of zinc oxide (ZnO) or barium titanate (BaTiO₃,BTO) dopants. The effects of key processing parameters on the morphology of nanofiber membranes were systematically investigated. In addition, the influence of zinc oxide (ZnO) or barium titanate (BTO) dopant concentrations on the piezoelectric properties of PVDF was examined. The microstructure, electrical performance, and β-phase content of the composite membranes were characterized. Results indicate that the composite film with a doping formulation of 16 wt% PVDF and 10 wt% ZnO exhibits optimal overall performance: the β-phase content of PVDF reaches 52.8%, and the output voltage reaches 1.5 V, which is 2.5 times higher than that of the undoped PVDF nanofiber membranes. This study provides an effective doping strategy for the fabrication of high-performance piezoelectric nanofiber membranes. Full article

Efficient synthesis routes for zinc oxide nanoparticles (ZnO NPs) that are rapid and non-toxic and operate at room temperature (RT) are essential to expand accessibility, minimize environmental impact, and enable integration with temperature-sensitive substrates. In this work, ZnO NPs were synthesized by probe ultrasonication at RT for durations from 30 s to 10 min and benchmarked against our previously reported water bath sonication method. A 10-min probe treatment yielded highly uniform ZnO NPs with particle sizes of 60–550 nm and a specific surface area of up to 75 m² g⁻¹, compared to ~38 m² g⁻¹ for bath sonication. These features were largely preserved after calcination at 500 °C. When integrated into chemiresistive devices, the resulting ZnO (P(10))-based sensors exhibited pronounced selectivity toward styrene, showing reversible responses at low concentrations (10–50 ppm) and stronger signals at higher levels (up to 200 ppm, with resistance changes reaching 2930%). The sensors demonstrated stable operation across 10–90% relative humidity, and consistent performance from −20 °C to 180 °C. Flexibility tests confirmed reliable sensing after 100 bending cycles at 30°. Overall, RT-probe ultrasonication offers a rapid, scalable, and eco-friendly route to ZnO NPs with tunable properties, opening new opportunities for flexible gas sensing. Full article

Zinc oxide nanoparticles (ZnO NPs) have garnered increasing attention in agriculture due to their potential to enhance plant growth and nutrient use. This research investigates the concentration-dependent effects of ZnO NPs on young crabapple (Malus robusta) plants, addressing gaps in understanding how different concentrations influence plant development. A hydroponic experiment was conducted, applying foliar treatments of 200 mg L⁻¹ ZnSO₄ (S200) and 200, 500, and 1000 mg L⁻¹ ZnO NPs (N200, N500, N100). The control group (CK) was treated with deionized water (dH₂O). Growth parameters, antioxidant enzyme activity, and nutrient contents were measured to evaluate the impact of ZnO NPs on plant development and nutrient uptake. The results showed that N200 enhanced growth, increasing plant height by 22.64%, total dry weight by 49.36%, and root length by 116.07%. In contrast, N500 and N1000 induced oxidative stress, elevating H₂O₂ and MDA by 32.02~54.43% and inhibiting growth. N200 also improved nutrient uptake, increasing K, Ca, Fe, and Zn uptake fluxes by 84.92%, 112.12%, 185.15%, and 149.92%, respectively, whereas N1000 suppressed overall nutrient uptake but increased root Ca accumulation by 64.59%. These findings suggest that ZnO NPs can enhance plant growth and nutrient utilization at low concentrations, with potential implications for agricultural practices involving nanoparticle (NP)-based fertilizers. Full article

Rechargeable zinc–air batteries (ZABs) are promising candidates for sustainable energy storage owing to their high theoretical energy density, safety, and environmental compatibility. However, their practical application is hindered by sluggish oxygen evolution reaction (OER) kinetics and the high charging voltage required, which reduce energy efficiency and accelerate electrode degradation. Here, we report for the first time the beneficial role of potassium iodide (KI) as a reaction modifier in ZABs employing manganese dioxide (MnO₂) as a bifunctional catalyst. MnO₂ not only exhibits remarkable electrocatalytic activity toward the oxygen reduction reaction (ORR) but also catalyzes the iodide oxidation reaction (IOR), which proceeds at significantly lower potentials than the OER. As a result, KI-modified MnO₂ ZABs achieve a remarkably low charging voltage of ≈1.8 V and an energy efficiency of 69.9% at 5 mA/cm². Although the IOR is not fully reversible in alkaline media and its effectiveness depends on the iodide concentration in the electrolyte—which may decrease upon repeated discharge–charge cycling—the suppression of electrode degradation enables stable operation for more than 200 charge–discharge cycles. These findings demonstrate the synergistic effect of KI and MnO₂ in enabling an efficient ORR/IOR pathway, providing a sustainable and cost-effective alternative to noble metal catalysts and opening new perspectives for the practical development of high-performance ZABs. Full article

Magnetic soft manganese–zinc ferrite in a concentration scale ranging from 100 to 500 phr was incorporated into acrylonitrile-butadiene rubber. The work was focused on the investigation of manganese–zinc ferrite content on electromagnetic interference shielding effectiveness and mechanical properties of composites. The rubber-based products used in industrial practice should not only provide good utility and functional properties but should also exhibit good stability towards degradation factors, like oxygen and ozone. Therefore, the samples were exposed to the thermo-oxidative and ozone ageing conditions, and the influence of both factors on the composites’ properties was evaluated. The results demonstrated that the incorporation of ferrite into the rubber matrix resulted in the fabrication of composites with absorption-shielding performance. It was demonstrated that the higher the ferrite content, the lower the absorption-shielding ability. Electrical and thermal conductivity showed an increasing trend with increasing content of ferrite. On the other hand, the study of mechanical properties implied that ferrite acts as a non-reinforcing filler, leading to a decrease in tensile characteristics. Thermo-oxidative ageing tests revealed that ferrite, mainly in high amounts, could accelerate the degradation processes in composites. Though the absorption-shielding performance of composites after ageing corresponded to that of their equivalents before ageing, it can also be concluded that the higher the amount of ferrite in the rubber matrix, the lower the composites’ stability against ozone ageing. Full article