Search Results (59)

Electroless nickel deposition (ELD) is an autocatalytic technique extensively used to impart conductive, protective, and mechanical functionalities to inherently non-conductive synthetic substrates. This review systematically explores the fundamental mechanisms of electroless nickel deposition, emphasising recent advancements in surface activation methods, solvent systems, and microstructural control. Critical analysis reveals that bio-inspired activation methods, such as polydopamine (PDA) and tannic acid (TA), significantly enhance coating adhesion and durability compared to traditional chemical etching and plasma treatments. Additionally, solvent engineering, particularly using polar aprotic solvents like dimethyl sulfoxide (DMSO) and ethanol-based systems, emerges as a key strategy for achieving uniform, dense, and flexible coatings, overcoming limitations associated with traditional aqueous baths. The review also highlights that microstructural tailoring, specifically the development of amorphous-nanocrystalline hybrid nickel coatings, effectively balances mechanical robustness (hardness exceeding 800 HV), flexibility, and corrosion resistance, making these coatings particularly suitable for wearable electronic textiles and smart materials. Furthermore, commercial examples demonstrate the real-world applicability and market readiness of nickel-coated synthetic fibres. Despite significant progress, persistent challenges remain, including reliable long-term adhesion, internal stress management, and environmental sustainability. Future research should prioritise environmentally benign plating baths, standardised surface activation protocols, and scalable deposition processes to fully realise the industrial potential of electroless nickel coatings. Full article

This study focuses on the evaluation of the effects of a natural treatment of limestone rock samples using microalgae known as diatoms. A total of 18 samples in the form of 50 mm cubes, carved from limestone rock from Boñar (Spain), were analyzed, divided into experimental and control groups with an equal number of samples. Through various tests evaluating porosity, water absorption, frost resistance, and salt crystallization, diatom-treated samples were found to show higher porosity and water absorption compared with the control samples, especially when the entire sample was analyzed as a whole. However, in tests focusing on the surface side most exposed to biodeposition, reduced water absorption was observed in the treated samples, suggesting an improvement in their antiabsorption properties. In addition, slightly higher frost resistance was detected in the treated samples. For this reason, this study provides valuable information on the potential of diatoms to influence the properties of limestone rocks, which can serve as a basis for future research in this field and for the development of more effective treatments to improve the characteristics of rocks used in various applications. Full article

Wood is a green and renewable bio-based building material, but its hygroscopicity affects its dimensional stability, limiting its use in construction. Chemical modification can improve its properties, yet its effectiveness depends on wood permeability and traditional modifiers. This study first used a deep eutectic solvent (DES) to boost the permeability of North American alder wood. Then, methyl trimethoxysilane was impregnated under supercritical carbon dioxide (SCI), pressure (PI), vacuum (VI), and atmospheric pressure (AI) conditions. DES treatment damaged the cell structure, increasing wood permeability. Silane was deposited and polymerized in the cell lumen, chemically bonding with cell-wall components, filling walls and pits, and thickening walls. The VI group had the highest absolute density (0.59 g/cm³, +36.6%) and the lowest moisture absorption (4.4%, −33.3%). The AI group had the highest ASE (25%). The PI group showed the highest surface hardness (RL, 2592 N) and a water contact angle of 131.9°, much higher than natural wood. Overall, the VI group had the best performance. Silane reacts with cellulose, hemicellulose, and lignin in wood via hydrolysis and hydroxyl bonding, forming stable bonds that enhance the treated wood’s hydrophobicity, dimensional stability, and surface hardness. Full article

Apatite and rare earth elements (REEs) are vital to the European Union’s economic growth and resource security, given their essential roles in fertilizers, green technologies, and high-tech applications. To meet rising demand and reduce reliance on imports, the exploitation of domestic deposits has become increasingly important. This study investigates the beneficiation potential of ore from a carbonatite complex (Finland), focusing on the recovery of fluorapatite concentrate through froth flotation. This research addresses two key objectives: evaluating the potential for REE enrichment alongside fluorapatite concentration using conventional anionic and amine-based reagents, and assessing separation efficiency when partially substituting the most effective conventional collectors with bio-based organosolv lignin nanoparticles. Adequate recovery rates for apatite and REEs were achieved using common anionic collectors, such as hydroxamate and sarcosine, yielding P grades of 23.4% and 21.5%, and recoveries of 96.4% and 89.2%, respectively. Importantly, concentrate quality remained stable with up to a 30% reduction in conventional collectors and the addition of organosolv lignin. Bench-scale trials further validated the approach, demonstrating that lanthanum and cerium recoveries exceeded 71%, alongside satisfactory apatite recovery. Lignin nanoparticles were observed to interact with both minerals; however, the interaction was more pronounced in the case of phlogopite, which exhibited a markedly greater increase in surface hydrophilicity following treatment, suggesting a stronger affinity or surface modification effect, which was beneficial to the performance of the separation process. Full article

Hepatitis A viral outbreaks continue to occur. It can be transmitted through aerosolized droplets and thus can contaminate surfaces and the environment. Ultraviolet light emitting diode (UV-C LED) systems are used for inactivation of microbes, though research is needed to determine optimal doses for aerosolized HAV inactivation. This study evaluates the UV-C LED doses for the inactivation of aerosolized hepatitis A virus (HAV) deposited on stainless-steel and glass discs. HAV was aseptically deposited onto stainless-steel or glass discs (1.27 cm diameter) using a nebulizer within a chamber followed by treatments for up to 1.5 min with 255 nm (surface dose = 0–76.5 mJ/cm²) or 279 nm (surface dose = 0–8.1 mJ/cm²) UV-C LED. Plaque assays were used to enumerate infectious titers of recovered viruses and data from three replicates were statistically analyzed. The calculated linear D₁₀-value (UV-C dose for a 1-log reduction in aerosolized deposits) for HAV by 255 nm UV-C LED was 47.39 ± 7.40 and 40.0 ± 2.94 mJ/cm² (R² = 0.94 and 0.91) and using 279 nm UV-C LED were 6.60 ± 0.27 and 5.57 ± 0.74 mJ/cm² (R² = 0.98 and 0.94) on stainless-steel and glass discs, respectively. The non-linear Weibull model showed δ (dose needed for a 1-log reduction in aerosolized HAV deposits) values for HAV of 29.69 ± 5.49 and 35.25 ± 15.01 mJ/cm² by 255 nm UV-C LED (R² = 0.99 and 0.92) and 6.67 ± 0.63 and 5.21 ± 1.25 mJ/cm² by 279 nm UV-C LED (R² = 0.98 and 0.95) on stainless-steel and glass discs, respectively. These data indicate that 279 nm UV-C LED showed higher efficiency for HAV inactivation than 255 nm UV-C LED, and that Weibull models were a better fit when tailing was observed. This study provides the inactivation data needed to aid in designing UV-C LED systems for delivering doses required to inactivate bio-aerosolized HAV deposits on stainless-steel and glass. Full article

As high-grade gold deposits are progressively depleted, the proportion of refractory gold ores in total reserves is continuously increasing, making gold recovery from refractory ores an inevitable trend in the future development of the gold industry. This study briefly analyzes the challenges faced during the leaching process of refractory gold ores under ambient conditions, and provides a detailed discussion on two acidic pretreatment technologies—pressure oxidation and bio-oxidation—as well as three acidic gold recovery technologies—thiosulfate leaching process, halogen leaching process, and thiocyanate leaching process. Additionally, this paper compares and analyzes the advantages and limitations of these acidic pretreatment and hydrometallurgical gold recovery technologies. The goal is to provide a comprehensive review of pretreatment technologies and leaching agents for refractory gold ores under acidic conditions (pH = 1–5), offering a reference for selecting appropriate treatment processes in the future, and to explore the potential development of acidic pretreatment and recovery technologies for refractory gold ores. Full article

This paper presents the role of soil nematodes as bio-indicators of the functioning of soil-plant beds in hydrophytic vertical-flow constructed wetland (VFCW) wastewater treatment plants. This study aimed to determine the abundance and trophic composition of nematode populations in seven soil-plant beds, the third component of plant-based wastewater treatment plants designed as Nature-Based Solutions (NBSs), in line with blue–green infrastructure and the closed-loop economy. The technology of this type of treatment plant is also in line with the idea of sustainability due to the very low energy requirements of the wastewater treatment system. In addition, soil nematodes were analysed in the soil adjacent to the WWTPs to assess the differences in trophic structure between these environments. The average nematode abundance in the soil-plant beds ranged from 606,000 [N·m⁻²] to 1,982,000 [N·m⁻²], with bacterivorous nematodes being the most abundant trophic group (61–73% of the population). This study’s results confirmed that soil-plant beds are abundantly populated by bacteria participating in key organic matter decomposition processes and nitrogen and phosphorus compound transformations, contributing to adequate wastewater treatment. The dominance of bacterivorous nematodes indicates a practical support of physicochemical and biological processes that reduce pollutant concentrations and eliminate pathogenic bacteria flowing into the deposits with the wastewater. Full article

The treatment of bone cancer often necessitates the surgical removal of affected tissues, with artificial implants playing a critical role in replacing lost bone structure. Functionalized implants represent an innovative approach to improve bio-integration and the long-term effectiveness of surgery in treating cancer-damaged bones. In this study, nickel-substituted hydroxyapatite (Ni:HAp) nanoparticles were deposited as thin films using laser pulses in the range of 30,000–60,000. Comprehensive structural, infrared, optical, morphological, surface, and magnetic evaluations were conducted on the synthesized Ni:HAp thin films. The magnetic hysteresis (M-H) loop demonstrated an increase in the saturation magnetization of the films with a higher number of laser pulses. A minimum squareness ratio of 0.7 was observed at 45,000 laser pulses, and the M-H characteristics indicated a shift toward ferromagnetic behavior, achieving the desired thermal response through an alternating magnetic field application within 80 s. Thermogravimetric analysis revealed distinct thermal stability, with the material structure exhibiting 46% degradation at 800 °C. The incorporation of bioactive magnetic nanoparticles in the thin film holds significant promise for magnetic hyperthermia treatment. Using HDOCK simulations, the interactions between ligand molecules and proteins were also explored. Strong binding affinities with a docking score of −67.73 were thus observed. The presence of Ca²⁺ ions enhances electrostatic interactions, providing valuable insights into the biochemical roles of the ligand in therapeutic applications. Intravenous administration of magnetic nanoparticles, which subsequently aggregate within the tumor tissue, combined with an applied alternating magnetic field, enable targeted heating of the tumor to 45 °C. This focused heating approach selectively targets cancer cells while preserving the surrounding healthy tissue, thereby potentially enhancing the effectiveness of hyperthermia therapy in cancer treatment. Full article

The viability of using Juncus acutus fibers as reinforcement material for developing lightweight sustainable non-structural construction materials in compliance with the valorization of local by-products has been investigated in this work. This study aims to investigate the effect of the chemical treatment of Juncus acutus fibers on the mechanical and hygric properties of bio-sourced clay–sand–Juncus acutus fiber composite. This lightweight specimen has been produced from a mixture of 60% natural clay and 40% sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers. The fibers were used as a partial replacement of sand in the mixture by volume at 0% (control specimen), 5%, 10%, and 20%. In order to enhance interfacial bonding between the fibers and the binder matrix, which seriously limits the strength development of the composite, the fibers have undergone an NaOH alkali treatment with different concentrations of 1 and 2 wt. %. Morphological and elementary chemical component evaluations based on SEM micrographs and EDX analyses revealed that the 1 wt. % NaOH alkali treatment exhibited the most beneficial effect due to the removal of impurity deposits without significant surface damage to the fibers. This finding was highlighted through the tensile tests carried out which showed the tensile stress value of 81.97 MPa compared to those of the treated fibers with 2% NaOH (74.45 MPa) and the untreated fibers (70.24 MPa). However, mechanical test results, carried out according to the European Standard EN 196-1, highlighted the beneficial effect of the fiber alkali treatment on both the compressive and flexural strengths, particularly for the fiber contents of 5% and 10%, which corresponds to a strengthening rate of 25% and 30%, respectively. The examination of the hygroscopic properties of the samples, including capillary water absorption, water diffusivity, and moisture buffering capacity under the dynamic conditions have indicated that the specimen containing treated fibers exhibited a better moisture regulating property than that obtained with untreated fibers. However, the specimens with treated fibers are classified as excellent hygric regulators based on their moisture buffer values (MBV > 2 g/(m².%RH)), according to the NORDTEST classification. The results also indicated that the capillary water absorption and the apparent moisture diffusivity of composites were lowered due to high fiber-matrix interfacial bond after fiber treatment. Consequently, the composite with treated fibers is less diffusive compared to that with untreated fibers, and thus expected to be more durable in a humid environment. Full article

Additive manufacturing (AM) is a rapidly developing technical field that is becoming an irreplaceable tool to fabricate unique complex-shaped parts in aerospace, the automotive industry, medicine, and so on. One of the most promising directions for AM application is the design and production of multi-material components with different types of chemical, structural, and architectural gradients that also promote a breakthrough in bio-inspired approaches. At the moment there are a lot of different AM techniques involving various types of materials. This paper represents a review of extrusion-based AM techniques using metal-polymer composites for structural metal parts fabrication. These methods are significantly cheaper than powder bed fusion (PBF) and directed energy deposition (DED) techniques, though have a lower degree of part detail. Thus, they can be used for low-scale production of the parts that are not rentable to produce with PBF and DED. Multi-material structures application in machinery, main aspects of feedstock preparation, the subsequent steps of extrusion-based 3D printing, and the following treatment for manufacturing single-metallic and multi-metallic parts are considered. Main challenges and recommendations are also discussed. Multi-metallic extrusion-based 3D printing is just a nascent trend requiring further wide investigation, though even now it shows pretty interesting results. Full article

The goal of this research work was to investigate the improvement of bio-oil issued from beechwood biomass through catalytic de-oxygenation. Pyrolysis was conducted in an auger reactor and the catalytic treatment was performed in a fluidized catalytic bed reactor. Lab-synthesized Fe-HZSM-5 catalysts with different iron concentrations were tested. BET specific surface area, BJH pore size distribution, and FT-IR technologies were used to characterize the catalysts. Thermogravimetric analysis was used to measure the amount of coke deposited on the catalysts after use. Gas chromatography coupled to mass spectrometry (GC-MS), flame ionization detection (GC-FID), and thermal conductivity detection (GC-TCD) were used to identify and quantify the liquid and gaseous products. The pyrolysis temperature proved to be the most influential factor on the final products. It was observed that a pyrolysis temperature of 500 °C, vapor residence time of 18 s, and solid residence time of 2 min resulted in a maximum bio-oil yield of 53 wt.%. A high percentage of oxygenated compounds, such as phenolic compounds, guaiacols, and the carboxylic acid group, was present in this bio-oil. Catalytic treatment with the Fe-HZSM-5 catalysts promoted gas production at the expense of the bio-oil yield, however, the composition of the bio-oil was strongly modified. These properties of the treated bio-oil changed as a function of the Fe loading on the catalyst, with 5%Fe-HZSM-5 giving the best performance. A higher iron loading of 5%Fe-HZSM-5 could have a negative impact on the catalyst performance due to increased coke formation. Full article

Background/Objectives: The intrinsic molecular heterogeneity of glioblastoma (GBM) is one of the main reasons for its resistance to conventional treatment. Mesenchymal GBM niches are associated with hypoxic signatures and a negative influence on patients’ prognosis. To date, competing endogenous RNA (ceRNA) networks have been shown to have a broad impact on the progression of various cancers. In this study, we decided to construct hypoxia-specific microRNA/ messengerRNA (miRNA/mRNA) networks with a putative circular RNA (circRNA) regulatory component using available bioinformatics tools. Methods: For ceRNA network construction, we combined publicly available data deposited in the Gene Expression Omnibus (GEO) and interaction pairs obtained from miRTarBase and circBank; a differential expression analysis of GBM cells was performed with limma and deseq2. For the gene ontology (GO) enrichment analysis, we utilized clusterProfiler; GBM molecular subtype analysis was performed in the Glioma Bio Discovery Portal (Glioma-BioDP). Results: We observed that miR-26b-5p, generally considered a tumor suppressor, was upregulated under hypoxic conditions in U-87 MG cells. Moreover, miR-26b-5p could potentially inhibit TRIB3, a gene associated with tumor proliferation. Protein-protein interaction (PPI) network and GO enrichment analyses identified a hypoxia-specific subcluster enriched in collagen-associated terms, with six genes highly expressed in the mesenchymal glioma group. This subcluster included hsa_circ_0001081/miR-26b-5p-affected COL15A1, a gene downregulated in hypoxic U-87 MG cells yet highly expressed in the mesenchymal GBM subtype. Conclusions: The interplay between miR-26b-5p, COL15A1, and TRIB3 suggests a complex regulatory mechanism that may influence the extracellular matrix composition and the mesenchymal transformation in GBM. However, the precise impact of the hsa_circ_0001081/miR-26b-5p axis on collagen-associated processes in hypoxia-induced GBM cells remains unclear and warrants further investigation. Full article

After the period of halogenated compounds, the period of nano-structured systems, and that of phosphorus (and nitrogen)-based additives (still in progress), following the increasingly demanding circular economy concept, about ten years ago the textile flame retardant world started experiencing the design and exploitation of bio-sourced products. Indeed, since the demonstration of the potential of such bio(macro)molecules as whey proteins, milk proteins (i.e., caseins), and nucleic acids as effective flame retardants, both natural and synthetic fibers and fabrics can take advantage of the availability of several low-environmental impact/“green” compounds, often recovered from wastes or by-products, which contain all the elements that typically compose standard flame-retardant recipes. The so-treated textiles often exhibit flame-retardant features that are similar to those provided by conventional fireproof treatments. Further, the possibility of using the same deposition techniques already available in the textile industry makes these products very appealing, considering that the application methods usually do not require hazardous or toxic chemicals. This review aims to present an overview of the development of bio-sourced flame retardants, focusing attention on the latest research outcomes, and finally discussing some current challenging issues related to their efficient application, paving the way toward further future implementations. Full article

The production of mineral fertilisers relies heavily on mineral deposits that are becoming depleted or is based on processes that are highly energy demanding. In this context, and in line with the circular economy and the European Green Deal, the recovery of nitrogen (N), phosphorus (P), and potassium (K) from organic wastes using chemical technologies is an important strategy to produce secondary raw materials for incorporation into mineral fertilisers, partially replacing the traditional sources of N, P, and K. However, there are very few studies on the agronomic and environmental effects of such substitution. The aim of this work was to evaluate plant growth under microcosm conditions and the effect on the soil microbiome of mineral fertilisers in which part of the N, P, or K content comes from bio-based materials (BBMFs), namely ash, struvite, and a patented chemical process. The crop was maize, and a metataxonomic approach was used to assess the effect on the soil microbiome. The BBMF treatments were compared with a control treated with a conventional mineral fertiliser. The conventional fertiliser performed significantly better than the bio-based fertilisers in terms of maize biomass production at the first sampling point 60 days after sowing (DAS), but at the last sampling point, 90 DAS, the BBMFs showed comparable or even better biomass production than the conventional one. This suggests that BBMFs may have a slightly slower nutrient release rate. The use of fertiliser, whether conventional or BBMF, resulted in a significant increase in microbiome biodiversity (Shannon index), while it did not affect species richness. Interestingly, the use of fertilisers modulated the composition of the bacterial community, increasing the abundance of beneficial bacterial taxa considered to be plant-growth-promoting bacteria, without significant differences between the conventional mineral fertilisers and the BBMFs. The predominance of PGPRs in the rhizosphere of crops when BBMFs are used could be part of the reason why BBMFs perform similarly or even better than conventional fertilisers, even if the rate of nutrient release is slower. This hypothesis will be tested in future field trials. Thus, BBMFs are an interesting option to make the food chain more sustainable. Full article

Poly(lactic) acid (PLA) is a bio-compatible polymer widely used in additive manufacturing, and in the form of cellular foam it shows excellent mechanical and piezoelectric properties. This type of structure can be easily 3D-printed by Fusion Deposition Modelling (FDM) with commercially available composite filaments. In this work, we present mechanical and electrical investigations on 3D-printed low-cost and eco-friendly foamed PLA. The cellular microstructure and the foaming degree were tuned by varying extrusion temperature and flowrate. The maximum surface potential and charge stability of disk samples were found in correspondence of extrusion temperature between 230 and 240 °C with a flowrate of 53–44% when charging on a heated bed at 85 °C. The cells’ morphology and correlated mechanical properties were analyzed and the measured piezoelectric $d_{33}$ coefficient was found to be 212 pC/N. These findings show the importance of printing parameters and thermal treatment during the charging process in order to obtain the highest charge storage, stability and material flexibility. These results suggest that 3D-printed cellular PLA is a promising sustainable material for sensing and energy-harvesting applications. Full article