Search Results (34,220)

TiO₂ nanotubes were synthesized using the anodization method on Ti foils and decorated with PbS nanoparticles by the SILAR method at different cycle numbers (10, 15, 20, 25, and 30). These samples were characterized using SEM, TEM, XRD, and microhardness tests. Morphologically, the PbS nanoparticles were evenly dispersed on TiO₂ nanotubes in the shape of small spheres. With an increase in the number of cycles, the size and shape of the nanoparticles increased. This also affected the structure and crystallinity of the PbS NPs, as the crystallite size of PbS increased. The in-depth analysis of the tribological characteristics of the coatings conducted using the scratch test allowed us to evaluate the adhesion of the coatings, a crucial aspect in determining their effectiveness and durability. Furthermore, we found that the wear resistance of the coatings increased with the number of PbS cycles up to 15 cycles. However, for the samples with higher size distribution and crystallite size, such as those with more than 15 cycles, the microhardness continued to decrease. This indicates that the addition of PbS can improve the durability of TiO₂ coatings, making them a potential candidate for advanced surface coatings in demanding engineering applications. Electrochemical measurements were conducted to assess the corrosion resistance of the samples. The electrochemical impedance spectra (EIS) results revealed that the PbS/TiO₂ coatings with 15 deposition cycles exhibited the most effective corrosion resistance, with a dense and uniform distribution of PbS nanoparticles forming a compact barrier that effectively protects against corrosion. The charge transfer resistance (R_ct) and the absorption capacitance (Q_ab) values were higher for the 15-cycle sample (4.49 Ω·cm² and 0.9 Fsⁿ⁻¹cm⁻², respectively). Full article

In the biodegradable metal class, Mg-based alloys are considered the most promising candidates for temporary implant manufacture. However, their high corrosion rate in physiological media is considered a main drawback for clinical translation. Conversion coatings address the limitations of Mg-based alloys and provide a strategy to control corrosion and improve surface biocompatibility. In this review paper, a detailed analysis of various conversion coating techniques, including ceramic conversion coatings based on metals, polymeric conversion coatings, bioactive conversion coatings, and hybrid conversion coatings, is performed. Attention is devoted to the corrosion process and parameters, as well as to the biological response in relation to bioactivity or biocompatibility. The main angiogenic and osteogenic signaling pathways are described based on the analyzed conversion coatings, and the evolution of the cellular response is estimated. Although significant progress has been made in the field, there are still challenges associated with synchronizing Mg alloy degradation with new bone formation and with precisely guiding cell signaling responses to achieve a desired biological response. An overall conclusion of the paper consists of the fact that conversion coatings are an important topic, as they can enhance the surface of Mg-based alloys, making them prone to clinical translation. Full article

To improve the adhesion and tribological performance of diamond-like carbon (DLC) coatings on steel substrate, a Ti-enhanced plasma nitriding (PNTi) layer was formed on the surface of 38CrMoAl steel, followed by deposition of a Cr-based interlayer (mainly CrN) and then a W interlayer. Finally, a DLC coating was deposited, resulting in a novel PNTi/DLC coating. For comparison, a conventional PN/DLC coating was prepared under the same processing conditions. Optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, hardness tests, and tribological experiments were performed to systematically investigate the effect of TiN-enriched PNTi supporting layer on the performances of the PNTi/DLC composite coating. The results show that comparing with PN/DLC composite coating, the critical load (Lc₂) of the PNTi/DLC coating was increased from 28.89 N to 43.25 N—about a 50% enhancement. The microhardness was increased from 2650 HV_0.05 to 4400 HV_0.05 (corresponding to 28.2 GPa to 44.1 GPa). The friction coefficient was decreased from 0.28 to 0.11, about a 60% reduction, and the wear rate declined more than 40%, from 4.81 × 10⁻⁶ to 2.90 × 10⁻⁶ mm³·N⁻¹·m⁻¹. The introduction of Ti promoted the in situ formation of TiN phase in the nitrided layer, which significantly improved the compactness of the nitrided layer and the adhesion at the film–substrate interface. Consequently, the PNTi/DLC composite coating exhibited excellent wear resistance and friction stability under high-load and severe tribological conditions. This study provides a promising perspective for engineering applications of steel-based DLC coatings in harsh service environments. Full article

This study systematically investigates the influence of CeO₂ content (0–0.6 wt.%) on the microstructure and mechanical properties of Stellite6/WC composite coatings fabricated by plasma spray welding. The phase composition and microstructure of the coatings were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), while microhardness and tribological performance were evaluated using a semi-automatic Vickers microhardness tester and a ball-on-disk tribometer. The results indicate that the coating with 0.4 wt.% CeO₂ exhibits the optimal combination of mechanical and tribological properties, achieving a maximum microhardness of 1107.62 HV_0.3—a 50.5% improvement over the unmodified coating—and a minimum wear mass loss of 1.4 mg, corresponding to a 78.1% reduction compared to the CeO₂-free counterpart. These findings demonstrate that appropriate CeO₂ addition significantly enhances both the microhardness and wear resistance of Stellite6/WC coatings, offering an effective strategy to mitigate surface degradation and extend the service life of 45 steel substrates under demanding operating conditions. Full article

Rakı, a traditional distilled beverage produced from grapes, holds significant economic importance in Türkiye; however, comprehensive consumer-focused sensory research remains limited. This study aims to determine the aroma profile, sensory characteristics, and consumer preferences of commercial rakı to guide producers in aligning product characteristics with consumer expectations. Nine commercial rakı samples were evaluated. The aroma composition was analyzed using SBSE-GC-MS. Sensory attributes were assessed by a trained panel through descriptive analysis (DA) and by 100 consumers utilizing the Check-All-That-Apply (CATA) method alongside a liking test. Eighty-one aroma compounds were identified, predominantly the phenylpropanoids trans-anethole and estragole, with monoterpenes and sesquiterpenes dominating the secondary profile. Integrating instrumental data with DA evaluations suggests that anethole and sesquiterpenes likely contribute to the attributes related to visual coating, body, creamy, mastic, persistency, and complexity. Consumer profiling revealed two distinct preference groups. Older, frequent consumers preferred complex, high-alcohol profiles with trigeminal harshness and visual glass coating, whereas younger, casual consumers preferred smoother rakı with a traditional white appearance, reacting negatively to “boiled aniseed” flavors and the yellowish tint of oak-aged versions. The CATA technique effectively distinguished these profiles. To enhance overall product quality, producers should eliminate “boiled” defects and adjust sensory profiles: complex products for experienced consumers and visually traditional, smooth profiles for younger consumers. According to current knowledge, this is the first study to employ the CATA method alongside consumer profiling and preference mapping in the sensory evaluation of rakı. Full article

Selenium nanoparticles (SeNPs) represent promising bioactive agents due to their reduced toxicity and multifunctional biological properties. In this study, SeNPs were synthesized via an eco-friendly phytosynthesis approach using Curcuma longa extract, yielding curcumin-functionalized selenium nanoparticles (cur–SeNPs). The composites (cur–SeNPs), either in native extract form or isolated, were incorporated into siloxane hybrid matrices prepared by the sol–gel method from tetraethyl orthosilicate: dimethyldimethoxysilane precursors, with polyvinylpyrrolidone (PVP) as a structural modifier. The host matrices were differentiated by the ratios between the precursors of the siloxane network, 3:1 for CS0–CS4, respectively, 1:1 for CS5, modified with PVP in the case of CS2 and CS3. These were loaded with cur–SeNPs–T in the cases of CS1, CS2, CS5 or with cur–SeNPs for CS3 and CS4. FTIR, XRD, SEM, and EDX analyses confirmed the formation of amorphous siloxane networks with well-dispersed SeNPs (up to ~12 wt%). PVP incorporation generated ordered mesoporous structures, increasing total pore volume sixfold and enlarging the average pore diameter to 9.26 nm. Studies about selenium ion release demonstrate that mesoporosity significantly enhances diffusion-controlled release. Antimicrobial assays against Staphylococcus aureus, Escherichia coli, and Candida albicans reveal a synergistic effect between curcuminoids and SeNPs, particularly in matrices with higher nanoparticle loading. The sol–gel technique for obtaining hybrid materials is very versatile regarding the supports on which the resulting materials or the compounds hosted in these host networks can be deposited. The dynamics of the development of hybrid materials is also reflected in the multitude of applications in various fields such as bio-medical, electronics, agriculture or food. Results obtained in this work highlight the potential of the developed systems for antimicrobial coatings on glass substrates and targeted delivery applications. Full article

Treatment for large critical-sized bone defects and impaired fracture healing remain challenging. Clinically used protein-based osteoinductive factors, such as recombinant bone morphogenetic proteins (BMPs), can be effective; however, they are costly and limited by stability, dose-delivery issues, and safety concerns. Preclinical small molecules offer an alternative because they are chemically stable, scalable to manufacture, and readily integrated for systemic administration or localized release from scaffolds, hydrogels, cements, and implant coatings. With an emphasis on delivery formats and mechanistic themes, this review examines small molecules that have been shown to improve bone regeneration in preclinical models, contrasting those of biological origin with synthetic and repurposed compounds. Across studies, these selected compounds promote osteoblast commitment, differentiation, and matrix mineralization via BMP/Smad signaling and Wnt/beta-catenin (β-catenin) activation, often through glycogen synthase kinase-3 beta (GSK-3β) inhibition or relief of pathway antagonism or Hedgehog (Hh) pathway stimulation. Beyond osteoinduction, several candidates address issues that commonly limit repair, including angiogenesis, oxidative stress, inflammatory tone, osteoimmune regulation, and suppression of osteoclast-mediated resorption. Direct head-to-head comparisons are rare across both classes and reporting heterogeneity complicates interpretation. Key translational gaps include limited cytotoxicity and immunologic profiling, dose and release optimization, durability of benefit, and insufficient evaluation of rational combinations. More rigorous in vivo studies, including larger animal models and standardized outcome metrics, are needed to prioritize promising candidates and guide clinical development. Full article

Currently, the resource wastage and safety hazards caused by fruit and vegetable spoilage are becoming increasingly prominent. Developing green, efficient, and non-toxic novel preservation materials has emerged as a hot spot in fruit and vegetable research. Based on this, this study utilized pomegranate peel as a raw material to prepare spherical multifunctional carbon dots (P-CDs) with an average particle size of 1.98 ± 0.58 nm through a one-step hydrothermal reaction. Subsequently, P-CDs were co-incorporated with L-cysteine (L-Cys) into a polyvinyl alcohol (PVA) and chitosan (CS) matrix to construct a novel composite coating material with combined antibacterial, antioxidant, and preservation functions. Experimental results demonstrate that P-CDs exhibit outstanding antioxidant activity and antibacterial performance. Compared to PVA/CS film, the P-CDs/L-Cys/PVA/CS film exhibited a 6.55 MPa increase in tensile strength and significantly enhanced thermal stability. Furthermore, the incorporation of P-CDs and L-Cys markedly boosted the PVA/CS film’s antioxidant activity (97% for ABTS; 85.69% for DPPH), antibacterial performance, and ultraviolet (UV) shielding capability. Coating cherry tomatoes with the P-CDs/L-cysteine/PVA/CS composite extended their shelf life by 6 days. This composite coating material exhibits preliminary biocompatibility and eco-friendly properties, aligning with green sustainable development needs and offering a novel potential solution for food preservation technology, while its practical applicability to food safety requires further comprehensive verification. Full article

Hot-filament chemical vapor deposition (HFCVD) facilitates the realization of industrial mass production owing to its simple synthesis device, facile control of process conditions, and low preparation cost. Reactive pressure is one of the deposition parameters that exert a profound influence on the growth of HFCVD diamond films on polycrystalline diamond (PCD) substrates, primarily affecting the growth rate and grain size of the deposited diamond coating. A univariate experimental approach was employed to investigate the effects of reactive pressure (2 kPa, 3 kPa, 4 kPa, 5 kPa) on the properties of as-deposited diamond films. The results show that with the increase in reactive pressure, the growth rate increased first and then decreased, peaking at 5.366 μm/h at 3 kPa. The fractal dimension and grain size follow a similar variation trend, both decreasing first and then increasing. The grain size drops to 15.8 nm when the reactive pressure is 3 kPa, at which point the adhesive strength of the film is maximized. This phenomenon can be attributed to the fact that excessively low reactive pressure extends the mean free path of particles and active species, endowing them with higher kinetic energy and reducing collision-induced energy loss. This in turn significantly promotes diamond nucleation, secondary nucleation and grain refinement, thus facilitating the growth of nanocrystalline diamond. In contrast, an excessively high pressure yields the opposite effect, inhibiting nucleation and promoting grain coarsening. Full article

Metal substrates were preprocessed via picosecond laser surface texturing (PLST, 532 nm) to fabricate interfacial microgrooves for tribological performance optimization prior to deposition of a magnesium silicate hydroxide (MSH)/graphite/MoS₂–PI solid lubricant coating. By tuning the PLST parameters (average laser power: 0.2–0.5 W, scan passes: 3–5, hatch spacing: 0.005–0.1 mm), three representative texture geometries (linear, circular, and square) were produced, and the resulting coating performance was compared with conventional mechanical polishing and sandblasting pretreatments. Among the three laser textures, the linear texture exhibited the most excellent tribological performance and interfacial adhesion, outperforming the circular and square counterparts. Ball-on-disk tests in a kerosene-contaminated environment (10 N, 800 rpm) showed that the linear-textured sample reached the lowest steady-state friction coefficient (0.038), lower than polished (0.048) and sandblasted (0.052) controls, together with reduced wear scar dimensions. Progressive-load scratch tests indicated a pronounced adhesion enhancement, with the critical failure load increasing from 7.05 N (polished) to 26.05 N for the linear-textured interface, which is higher than 21.21 N (circular) and 23.78 N (square) textures. Cross-sectional microscopy and EDS mapping reveal that the laser-defined microgrooves (~15 μm depth, ~120 μm width, ~500 μm spacing) act as a parameter-controlled interfacial architecture that promotes mechanical interlocking and provides lubricant-rich reservoirs. This laser-enabled interfacial design suppresses delamination, supports transfer film stability, and ultimately enhances the coating’s tribological performance by reducing friction and wear. Full article

Plant-derived antimicrobial compounds are emerging as promising alternatives to synthetic preservatives in the food industry due to their efficacy against a broad spectrum of pathogenic and spoilage microorganisms, as well as their consumer acceptance. This review critically examines the main classes of bioactive phytochemicals, including essential oils, polyphenols, alkaloids, terpenoids, and saponins, comparing their relative antimicrobial effectiveness and highlighting representative examples. Notably, essential oils rich in thymol or carvacrol have shown strong inhibitory activity against Listeria monocytogenes and Salmonella spp., while polyphenols and alkaloids exhibit moderate to strong activity depending on concentration and food matrix. Their mechanisms of action include cell membrane disruption, inhibition of key enzymes, and interference with DNA or protein synthesis. Applications in food systems (i.e., incorporation into coatings, emulsions, or controlled-release formulations) demonstrate potential for extending shelf life and enhancing safety. However, practical implementation is challenged by matrix-dependent efficacy, compound stability, sensory impact, and regulatory and toxicological considerations. By synthesizing current knowledge, identifying the most promising compound classes, and highlighting key limitations, this review provides a critical framework to guide future research and the development of effective, sustainable natural preservatives in the food industry. Full article

Gypsum-based materials are widely used in construction but suffer from poor water resistance and durability, limiting their application in moisture-prone environments. While fiber-reinforced modified gypsum (FRMG) improves mechanical performance, the lack of systematic research on waterproofing strategies and their influence on both durability and strength remains a key challenge. This study investigated three waterproofing methods: surface coating with paraffin emulsion, internal incorporation of paraffin emulsion, and internal incorporation of vinyl acetate ethylene (VAE) emulsion. The workability, water absorption, mechanical properties, contact angle, and microstructure of the FRMG matrix were analyzed. The results showed that surface coating provided only short-term waterproofing. Internal incorporation of paraffin emulsion reduced water absorption but weakened mechanical performance. In contrast, VAE emulsion formed continuous polymer films that filled pores, significantly reducing water absorption while improving flexural and compressive strength, with optimal performance observed at a 6% dosage. In addition, increasing emulsion content enhanced hydrophobicity. These results indicate that VAE-based internal modification is an effective approach to improving the durability and performance of gypsum-based materials, providing guidance for their application in interior wall systems and prefabricated building components. Full article

Atmospheric plasma spraying (APS) represents a critical solution for enhancing the durability of agricultural components, such as harrow discs, which are subjected to synergistic wear and corrosion during soil cultivation. This study presents experimental results evaluating the electrochemical corrosion behavior and thermal shock resistance of discs coated via atmospheric plasma thermal spraying. Both metallic and ceramic materials, in powder form, from established manufacturers were used to produce the coatings, and the three types of coatings (two metallic and one ceramic) have the following chemical compositions and trade names: W₂C/WC12Co (Metco71NS), Cr₂O₃-4SiO₂-3TiO (Metco136F) and Co25.5Cr10.5Ni7.5W0.5C (Metco45C-NS). The coatings were analyzed using electron microscopy to evaluate the surfaces following corrosion testing. The ceramic coating based on the Cr₂O₃-4SiO₂-3TiO demonstrated the highest protective efficiency by increasing the charge transfer resistance from 307 Ω/cm² to 2213 Ω/cm² for the ceramic coating. It provided a superior physical barrier, reducing the corrosion current density from 0.140 mA/cm² for unprotected substrate to 0.004 mA/cm², representing an improvement of nearly two orders of magnitude. These findings demonstrate that implementing Cr₂O₃-4SiO₂-3TiO ceramic systems can significantly extend the operational lifespan of soil-engaging components, providing a cost-effective strategy for reducing maintenance intervals and material loss in aggressive agricultural environments. Full article

The practical application of inorganic ferroelectric fillers in flexible piezoelectric composites is critically constrained by low polarization efficiency and severe interfacial incompatibility with polymer matrices. Herein, we report a multi-level in situ surface modification strategy that simultaneously addresses both limitations. High-purity one-dimensional tetragonal barium titanate nanofibers (BTO NFs) are first synthesized via sol–gel electrospinning combined with a two-step gradient annealing process, which precisely controls phase evolution and preserves structural continuity. To overcome the detrimental acid-induced degradation of BTO NFs during functionalization, a polydopamine (PDA) buffer layer is first conformally coated, followed by the liquid-phase deposition of a conductive polypyrrole (PPy) shell, forming a robust core–shell PPy@PBT NFs architecture. Incorporating only 4 wt% of these multifunctional fillers into a poly(vinylidene fluoride) (PVDF) matrix yields a dramatic enhancement in electromechanical performance. The resulting flexible piezoelectric energy harvesters achieve a piezoelectric coefficient (d₃₃) of 28.7 pC/N, an output voltage of 13 V, and an output current of 0.7 μA, representing substantial improvements over unmodified filler systems. This synergistic enhancement originates from the PDA-mediated interfacial stress transfer and the PPy-induced Maxwell–Wagner polarization intensification, establishing a robust and generalizable paradigm for high-performance flexible piezoelectric composites in self-powered wearable electronics. Full article

This study investigated the biosynthesis of magnetite nanoparticles mediated by chia mucilage (CM-Fe₃O₄ NPs) and their application in the co-encapsulation of Lactobacillus rhamnosus GG (LGG) using spray drying. CM-Fe₃O₄ NPs were synthesized by combining CM extract with iron salts, in which hydroxyl and carbonyl groups of CM acted as natural ligands for Fe²⁺/Fe³⁺ ions. A response surface design was applied to optimize synthesis parameters, focusing on size distribution and zeta potential, and confirming the influence of pH on colloidal stability. Characterization by FE-SEM, DLS, XRD, UV-Vis, and FTIR revealed spherical particles with an inorganic core (50–300 nm) and a hydrated organic coating (600–900 nm), consistent with a spinel structure functionalized by CM. Spray-drying encapsulation tests showed that incorporating CM-Fe₃O₄ NPs did not compromise bacterial viability, maintaining optimal moisture content and survival. Growth curves and confocal microscopy corroborated the physiological compatibility of the nanoparticles, with no alterations in LGG morphology or growth dynamics. Under simulated gastrointestinal conditions, co-encapsulated microcapsules exhibited slightly improved survival in the gastric phase and significantly greater viability in the initial intestinal phase. These results suggest that CM-Fe₃O₄ NPs modulate matrix degradation and promote controlled release, ensuring therapeutic concentrations of LGG in the intestine. Overall, the CM-Fe₃O₄ nanocomposite system integrates the protective properties of biopolymers with the functional advantages of iron nanoparticles, offering dual functionality: probiotic stabilization and potential iron supplementation. This innovative, food-grade approach supports the development of next-generation functional foods with combined therapeutic and nutritional benefits. Full article