Search Results (1,029)

Polyhydroxybutyrate (PHB) is considered a coating material capable of limiting the corrosion of biodegradable metallic implants due to its biocompatibility and ability to form a physical barrier. In this study, PHB was deposited on commercial AZ91D magnesium alloy using the spin coating technique. To improve adhesion at the polymer–substrate interface, the magnesium substrates were subjected to atmospheric pressure plasma treatment for different exposure times (5, 10, or 15 min) before coating. The optimal treatment time of 5 min significantly increased substrate wettability and surface free energy, facilitating stronger PHB adhesion. In addition, the PHB coatings were subjected to atmospheric pressure plasma treatment for 5, 10, or 15 s to evaluate potential surface modifications. Corrosion behavior under simulated physiological conditions was assessed via potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in HANK’s solution at 37 °C. Pull-off tests were used to evaluate the adhesion strength between the coating and the substrate under each treatment condition. The results showed a significant decrease in the corrosion rate (V_corr), from 4.083 mm/year for bare Mg-AZ91D to 0.001 mm/year when both the substrate and the polymer received plasma treatment. This indicates that the treatment modifies surfaces and improves interfacial bonding, enhancing polymer–metal interaction and producing durable, biocompatible coatings for medical implants. Full article

Heavy metals (arsenic, cadmium, and lead) remain one of the most common and complex environmental problems worldwide. Accordingly, there is a growing need for eco-friendly and affordable materials derived from agricultural waste for the removal of heavy metals from contaminated water. This study aims to demonstrate how biodegradable pineapple leaf cellulose (PLC) can be used effectively in the remediation of heavy metals. The PLC adsorbent was prepared by treating it with ethyl alcohol (EtOH, 99.5%), calcium chloride (CaCl₂), and 0.8 M sodium hydroxide. A scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) was used to investigate the surface of the adsorbent. Inductively coupled plasma mass spectrometry (ICP-MS) was employed to measure the concentration of metals before and after adsorption. Removal of metal ions (As⁵⁺, Cd²⁺, and Pb²⁺) by PLC was investigated under varying conditions, including pH, contact time, and adsorbent dosage. The analysis of cellulose composite revealed significant potential for adsorption of heavy metals such as As⁵⁺, Cd²⁺, and Pb²⁺. The highest removal efficiency of heavy metal ions was detected at a pH ranging from 3 to 7. The biosorption order of PLC at pH 6 was Pb²⁺ > Cd²⁺ > As⁵⁺ with 99.53% (63.45 mg/g), 98.44% (37.23 mg/g), and 42.40% (16.27 mg/g), respectively. After 120 min, the equilibrium of the adsorption process was reached for As⁵⁺, Cd²⁺, and Pb²⁺. FT-IR characterization discovered an increased abundance of functional groups on the adsorbent. The SEM-EDS analysis confirmed the occurrence of elements on the surface of PLC. The study revealed that the use of PLC is an innovative method for removing heavy metals from aquatic milieus, a potential resource for eco-friendly and affordable wastewater treatment. Full article

Active screen plasma nitriding (ASPN) of additively manufactured nickel-based superalloys represents an understudied surface enhancement pathway. This study presents the first systematic investigation of ASPN applied to additively manufactured Inconel 939 (IN 939), evaluating four distinct post-processing routes combining heat treatment atmospheres (argon versus air cooling), vibratory finishing, and lapping under identical nitriding parameters (450 °C, 8 h, 25% N₂ + 75% H₂, 3 hPa). Contrasting nitriding behaviours emerged as a function of the post-processing route: the air-cooled thermal treatment (HT-air-vibr-lap) promotes formation of a thick Al/Cr-rich oxide layer (10–15 µm) that substantially inhibits nitrogen diffusion, resulting in thin and discontinuous nitrided layers. Conversely, the inert atmosphere route (HT-Ar-vibr-lap) circumvents oxide formation, enabling continuous S-phase (expanded austenite, γN) layer development of a 6.4 ± 0.3 µm thickness with exceptional surface hardness (~1200 HV, representing 3–4× enhancement relative to base material). X-ray diffraction confirmed S-phase formation with refined lattice parameter (3.609 Å) and secondary nitride phases (CrN-type and NbN/TaN-type precipitates). The post-processing sequence—particularly heat treatment atmosphere and mechanical finishing methodology—emerged as a critical controlling parameter for S-phase formation efficiency and mechanical properties of nitrided layers in additively manufactured nickel-based superalloys. This work addresses a knowledge gap distinct from the existing literature on conventional Inconel systems, establishing that controlled surface modification through post-processing can achieve the required properties. Full article

Natural fibers are increasingly used as sustainable, lightweight, and low-cost alternatives to glass fibers in polymer composites. However, their inherent hydrophilicity and surface polarity limit compatibility with non-polar polymer matrices. Both gas/solid and plasma fluorination modify only the surface of lignocellulosic materials. Mild conditions are mild, with reactivity governed by fluorine concentration, temperature, and material composition. Surface energy is typically assessed through contact-angle measurements and surface analytical techniques that quantify changes in hydrophobicity and chemical functionalities. In wood, fluorination proceeds preferentially in lignin-rich regions, making lignin a key component controlling reactivity and the spatial distribution of fluorinated groups. Natural fibers follow the same logic as for flax, which is a representative example of lignin content. Applications of fluorinated bio-based materials include improved moisture resistance, enhanced compatibility in composites, and functional surfaces with tailored wetting properties. Scalability depends on safety, cost, and process control, especially for direct fluorination. Durability of the treatment varies with depth of modification, and environmental considerations include the potential release of fluorinated species during use or disposal. Full article

Inconel 718 is widely used in chloride-bearing environments where localized corrosion resistance is critical. This study assesses the effect of continuous low-temperature plasma nitriding (425 °C, 2 h) on the microstructure, hardness, and localized corrosion behavior of Inconel 718. The nitriding treatment produced a surface layer with hardness values up to three times higher than those of the untreated material, associated with a nitrided layer of thickness 6.1–6.7 µm. X-ray diffraction confirmed the precipitation of CrN without the formation of nitrogen-expanded phases. Cyclic polarization tests revealed non-significant changes in the corrosion parameters, except for a two-fold increase in the corrosion rate of nitrided samples. Also, the critical pitting temperature (CPT) decreased by more than 30 °C on average in the nitrided condition, falling below 10 °C. These findings indicate that, although continuous plasma nitriding enhances surface hardening, it significantly compromises the alloy’s resistance to localized corrosion in chloride-rich environments. Full article

Polyethylene (PE) films are widely used as waterproofing materials on the surfaces of metal pipelines. Poor adhesion of PE films to a metal substrate reduces durability, leading to shorter service life and higher economic costs. The current research aims to study the modification of PE films in atmospheric pressure gliding arc plasma (GAP). The adhesion properties of the modified films were investigated using the contact angle method and adhesion work calculations. During the modification process, the GAP treatment duration and deflector nozzle angle of attack were optimized to 10 s and 135°, respectively. It was established that the adhesion work increased from 62.1 to 141.3 mJ/m² after 10 s GAP modification compared to untreated PE. GAP modifying of PE films for 30 s or more is impractical, as the increase in the adhesion work ceases after that. It was found that surface roughness R_max increased by up to 4.1 times after 10 s GAP modification compared with nontreated PE. The PE films acquired hydrophilic properties after plasma modification, due to changes in the polymer surface’s chemical structure. The results of IR spectroscopy studies indicated oxidation of the film surface, an increase in the concentration of surface polar groups (-COOH, OH, C=O), and the formation of double bonds (C=C), which led to improved adhesive properties. A study of the electret properties showed that the observed decline and subsequent stabilization of values occurred within the first 24 h. Mechanical tests indicated improved performance of the GAP-modified PE films compared to the non-treated ones in the PE–mastic–PE and PE–mastic–steel systems. Due to their enhanced contact properties, the modified PE films are of interest as a base material for creating waterproofing materials. Full article

Neuromorphic computing, an emerging computational paradigm, aims to overcome the bottlenecks of the traditional von Neumann architecture. Two-dimensional materials serve as ideal platforms for constructing artificial synaptic devices, yet existing devices based on these materials face challenges such as insufficient stability. Indium selenide (InSe), a two-dimensional semiconductor with unique properties, demonstrates significant potential in the field of neuromorphic devices, though its application research remains in the initial stage. This study presents an artificial synaptic device based on the InSe/Charge Trapping Layer (CTL)/h-BN heterojunction. By applying oxygen plasma treatment to h-BN to form a controllable charge-trapping layer, efficient regulation of carriers in the InSe channel is achieved. The device successfully emulates fundamental synaptic behaviors including paired-pulse facilitation and long-term potentiation/inhibition, exhibiting excellent reproducibility and stability. Through investigating the influence of electrical pulse parameters on synaptic weights, a structure–activity relationship between device performance and structural parameters is established. Experimental results show that the device features outstanding linearity and symmetry, realizing the simulation of key synaptic behaviors such as dynamic conversion between short-term and long-term plasticity. It possesses a high dynamic range ratio of 7.12 and robust multi-level conductance tuning capability, with stability verified through 64 pulse cycle tests. This research provides experimental evidence for understanding interfacial charge storage mechanisms, paves the way for developing high-performance neuromorphic computing devices, and holds broad application prospects in brain-inspired computing and artificial intelligence hardware. Full article

Background and Objectives: The aim of this study is to employ quantitative proteomics to elucidate the molecular mechanism and signaling pathways modulated by plasma rich in growth factors (PRGF) in a murine model of geographic atrophy (GA)-like retinal degeneration. Materials and Methods: C57BL/6J mice were used as a model GA-like retinal degeneration by a single systemic NaIO₃ administration. Animals were divided into three groups: Control (PBS), Disease (NaIO₃ + PBS), and PRGF-treated (NaIO₃ + PRGF). After 7 days, retinas and retinal pigment epithelium were collected for proteomic analysis. Proteins were extracted, digested using the FASP method, and analyzed by Data-Independent Acquisition (DIA-PASEF) mass spectrometry; data were processed with DIA-NN and statistically analyzed with Perseus. Functional pathway analysis was performed using Ingenuity Pathway Analysis. Results: A total of 6511 proteins were identified. The Disease model showed the expected deregulation of pathways related to oxidative stress, inflammation, and fibrosis. Comparison between the PRGF and Control groups showed that PRGF significantly reduced oxidative and cellular stress proteins/pathways. In the same way, when PRGF and Disease groups were compared, PRGF treatment showed a significant reduction in pathways associated with inflammation, oxidative stress, and cellular stress. PRGF also activated several homeostatic pathways not only related to neuroprotective pathways but also with the lipid deposition (drusen) reduction. All these results suggest that PRGF treatment exerts a protective effect against NaIO₃-induced retinal damage. Conclusions: These findings suggest that PRGF effectively mitigates the degenerative effects of NaIO₃ by activating specific protective and compensatory signaling pathways in the retina. PRGF is indicated as a promising new therapeutic option for ameliorating age-related macular degeneration progression. Full article

Background and Objectives: IgA nephropathy represents the most prevalent form of primary glomerulonephritis around the world, with significant heterogeneity in management strategies and outcomes. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of pharmacological interventions for IgA nephropathy. Materials and Methods: We searched multiple databases through June 2025, identifying randomized controlled trials and observational studies evaluating pharmacological treatments in biopsy-proven IgA nephropathy. Primary outcomes included proteinuria reduction and estimated glomerular filtration ration (eGFR) preservation. Secondary outcomes included hard kidney endpoints and safety parameters. Random-effects meta-analyses were performed with comprehensive risk–benefit assessments. Results: Twenty-five studies were included. B-cell/plasma-cell-targeted therapies showed significant proteinuria reduction (−34.0% [95% CI: −45.7, −22.3%]), complement pathway inhibitors demonstrated superior eGFR preservation (+5.8 mL/min/1.73 m²/year [95% CI: 2.4, 9.2]). Systemic corticosteroids showed observed hard outcome benefits (HR 0.37 [95% CI: 0.26, 0.52]) but highest adverse event risk (RR 3.28 [95% CI: 2.11, 5.09]). Novel agents showed projected favorable effects (B-cell: HR 0.38; complement: HR 0.42) pending validation. Conclusions: Novel targeted therapies, especially B-cell/plasma-cell-targeted agents and complement pathway inhibitors, show promising risk–benefit profiles. However, longer-term data and standardized eGFR slope reporting are needed to confirm these findings compared to other immunosuppressive agents. Full article

Embedding flexible electronic circuits into a sustainable polymer is an emerging and significant topic in the field of in-mold electronics (IME). Ensuring strong adhesion between the flexible circuit and the molded polymer is critical for the durability of IME products. In this study, three different types of etched copper polyimide (PI) foils were used as the substrate of electronic components. Two bio-based and biodegradable polymers of polylactic acid (PLA) and polyhydroxybutyrate (PHB) served as the overmolding material. Four different surface pretreatments: drying, polydopamine (PDA) coating, PDA coating followed by thermal treatment under vacuum, oxygen plasma, and 3-aminopropyltriethoxysilane (APTES) were applied to the PI surface prior to the overmolding process to investigate the influence on the adhesive strength. Additionally, a thermoplastic polyurethane (TPU) adhesive layer was introduced via vacuum lamination to further improve adhesion. The main objective of this study was to evaluate the adhesive strength between etched PI and overmolded biopolymers before and after surface modifications. The loci of failure were analyzed using scanning electron microscopy (SEM). The results indicate that laminated TPU is the most effective approach for improving adhesion between polyimide foils and biopolymers. Full article

Microwave heating technology has gained extensive application in various fields, including food processing and drying, material synthesis, and waste treatment, due to its advantages of high efficiency, selectivity, and rapid response. However, the inherent non-uniform electromagnetic field distribution within metallic microwave cavities leads to uneven heating. This issue severely constrains the large-scale industrial application of microwave heating, particularly its extension into high-precision, high-value-added industrial sectors like 3D printing, curing, and microwave plasma micro/nano-fabrication. To address this challenge, extensive research efforts have been undertaken in both academia and industry, focusing on improving microwave heating uniformity, resulting in the proposal of various methods. This review summarizes these methods for enhancing microwave heating uniformity and specifically outlines recent research progress on novel techniques based on artificial electromagnetic surfaces. It aims to offer valuable references and guidance for the broader application of microwave heating technology. Full article

Non-thermal plasma (NTP) is a fast, reagent-free technology for dye removal, yet its performance is highly dependent on the operating conditions and on plasma–catalyst interactions. In this work, a coaxial falling-film dielectric barrier discharge (DBD) reactor was optimized for the degradation and decolorization of organic dyes, with ceria (CeO₂) employed as a catalyst. For the first time, CeO₂ prepared via a supercritical antisolvent (SAS) micronization route was tested in plasma-assisted dye decolorization and directly compared with its non-micronized counterpart. Optimization of plasma parameters revealed that oxygen feeding, an input voltage of 12 kV, a gas flow of 0.2 NL·min⁻¹, and an initial dye concentration of 20 mg·L⁻¹ resulted in the fastest decolorization kinetics. While the anionic dye Acid Yellow 36 exhibited electrostatic repulsion and negligible plasma–ceria synergy, the cationic dyes Crystal Violet and Methylene Blue showed strong adsorption on the negatively charged CeO₂ surface and pronounced plasma–catalyst synergy, with SAS-derived CeO₂ consistently outperforming the non-micronized powder. The SAS catalyst, characterized by a narrow particle size distribution (DLS) and spherical morphology (SEM), ensured improved dispersion and interaction with plasma-generated species, leading to significantly shorter decolorization radiation times compared to the literature benchmarks. Importantly, this enhancement translated into higher energy efficiency, with complete dye removal achieved at a lower specific energy input than both plasma-only operation and non-micronized CeO₂. Scavenger tests confirmed •OH radicals as the dominant oxidants, while O₃, O₂•⁻, and e⁻_a played secondary roles. Tests on binary dye mixtures (CV + MB) revealed synergistic decolorization under plasma-only conditions, and the CeO₂-SAS catalyst maintained high overall efficiency despite competitive adsorption effects. These findings demonstrate that SAS micronization of CeO₂ is an effective material-engineering strategy to unlock plasma–catalyst synergy and achieve rapid, energy-efficient dye abatement for practical wastewater treatment. Full article

In this work, plasma nitriding was carried out to improve the corrosion resistance of API 5L X70 steel. The process was conducted at different treatment times, 4, 6, 8, and 10 h, to determine which one provides greater resistance to corrosion. The conditions under which the nitriding was carried out were as follows: a mixture of 20% N₂ and 80% H₂ at 3 torr pressure, a current of 2.6 × 10⁻⁶ A, a voltage of 360 V, and the temperature inside the plasma chamber was 550 °C. The blank and nitrided materials were characterized using dispersive energy spectroscopy and scanning microscopy to study their morphology and chemical composition. In addition, open potential circuit, electrochemical impedance spectroscopy, and potentiodynamic polarization curves in simulated soil solution were performed to evaluate the materials’ corrosion resistance. The treatment achieved at 10 h presented the greatest corrosion resistance, reducing the corrosion current density up to three orders of magnitude. The thickness reached 678.75 µm for this condition. Full article

The growing demand for sustainable, high-performance, and structurally reliable construction materials has intensified research on natural fibre-reinforced composites (NFCs). Among these, hemp stands out due to its high cellulose content, low density, excellent tensile strength, and renewability, making it a promising reinforcement for cementitious and other inorganic matrices, including lime- and geopolymer-based systems. This review focuses exclusively on structural and civil engineering applications, while polymer-based composites are mentioned only for comparative context regarding adhesion and durability. A comprehensive bibliometric and technical analysis was conducted to evaluate the effectiveness of hemp fibre treatment methods in improving fibre–matrix adhesion, mechanical performance, and long-term durability. A systematic search covering major scientific databases from 2014 to 2024 identified global research trends, key treatment techniques, and their performance outcomes. Both chemical (alkaline, silane, acetylation, alkyl ketene dimer—AKD) and physical (plasma, ozone) modification strategies were critically assessed for adhesion, mechanical strength, hydrophobicity, and resistance to environmental cycling. Quantitative results indicate that combined alkaline–AKD treatments produce the most consistent improvement, increasing compressive strength by approximately 30% and flexural strength by up to 25% compared with untreated composites. Physical surface treatments were also found to enhance roughness and interfacial bonding without degrading fibre integrity. Unlike previous reviews that address natural fibres in general, this article specifically targets hemp fibre treatments for inorganic matrices, correlating modification mechanisms with the structural performance indicators relevant to civil engineering. By integrating bibliometric mapping of research evolution, keyword networks, and technological gaps, this review provides a quantitative and engineering-oriented synthesis that highlights its original contribution to sustainable and resilient construction materials. The findings emphasise the need for standardised testing protocols and performance-based evaluations to enable the broader structural application of hemp-based composites in modern construction. Full article