Search Results (537)

Agriculture is one of the most important sectors of the global economy, but it increasingly faces sustainability challenges in meeting rising food demands. The intensive use of mineral fertilizers not only improves yields, but also causes negative environmental impacts such as increasing greenhouse gas emissions, water eutrophication, and soil degradation. To develop more sustainable solutions, the focus is on organic fertilizers, which are produced using waste and biostimulants such as amino acids. The aim of this study was to develop and characterize liquid nitrogen–calcium–magnesium fertilizers produced by decomposing dolomite with nitric acid followed by further processing and to enrich them with a powdered amino acid concentrate Naturamin-WSP and liquid extracts from digestate, a by-product of biogas production. Nutrient-rich extracts were obtained using water and potassium hydroxide solutions, with the latter proving more effective by yielding a higher organic carbon content (4495 ± 0.52 mg/L) and humic substances, which can improve soil structure. The produced fertilizers demonstrated favourable physical properties, including appropriate viscosity and density, as well as low crystallization temperatures (eutectic points from –3 to –34 °C), which are essential for storage and application in cold climates. These properties were achieved by adjusting the content of nitrogenous compounds and bioactive extracts. The results of the study show that liquid fertilizers enriched with organic matter can be an effective and more environmentally friendly alternative to mineral fertilizers, contributing to the development of the circular economy and sustainable agriculture. Full article

Cobalt and Nickel (Co, Ni) co-doped magnesium oxide (MgO) nanoparticles (NPs) have been synthesized using the coprecipitation method. The structural, chemical, and optical properties of the as-synthesized NPs are systematically investigated using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and UV-visible spectroscopy. It is found that the optical bandgap of co-doped MgO NPs reduces from 2.30 to 1.98 eV (14%) with increasing Ni dopant concentrations up to 7%. The Co_0.05Ni_0.07Mg_0.88O NPs exhibit a high photocatalytic degradation efficiency of 93% for methylene blue dye (MB) under natural sunlight irradiation for 240 min. Our findings indicate that the Co_0.05Ni_xMg_0.95−xO NPs have strong potential for use as photocatalysts in industrial wastewater treatment. Full article

In the process of the work of a coal power station is formed ash and slag, which, along with process water, are deposited in the dumps. Coal ash waste dumps significantly degrade the surrounding environment due to their unprotected surfaces, which are highly susceptible to wind and water erosion. This results in the dispersion of contaminants into adjacent ecosystems. Pollutants migrate into terrestrial and aquatic systems, compromising soil quality and water resources, and posing documented risks to the environment and human health. Primary succession on the coal ash dumps of the Apatity thermal power plant (Murmansk Region, NW Russia) was initiated by cyanobacterial colonization. We studied cyanobacterial communities inhabiting three spoil sites that varied in time since decommissioning. These sites are characterized by exceptionally high concentrations of calcium and magnesium oxides—levels approximately double those found in the region’s natural soils. A total of 18 cyanobacterial taxa were identified in disposal sites. Morphological analysis of visible surface crusts revealed 16 distinct species. Furthermore, 24 cyanobacterial strains representing 11 species were successfully isolated into unialgal culture and tested with a molecular genetic approach to confirm their identification from 16S rRNA. Three species were determined with molecular evidence. Cyanobacterial colonization of coal fly ash disposal sites begins immediately after deposition. Primary communities initially exhibit low species diversity (four taxa) and do not form a continuous ground cover in the early years. However, as succession progresses—illustrated by observations from a 30-year-old deposit—spontaneous surface revegetation occurs, accompanied by a marked increase in cyanobacterial diversity, reaching 12 species. Full article

The accelerated hydrolytic degradation of poly(L-lactide) (PLA)/magnesium (Mg) composite films was investigated to elucidate the influence of surface modification of Mg particles on the degradation behavior and characteristics of PLA composites. Accelerated degradation studies were conducted at 60 °C in a pH 7.4 phosphate-buffered solution over 7 weeks, with degradation monitored using several techniques: mass loss, water absorption, thermal analysis, and Raman spectroscopy. The results indicated that all composite films experienced more than 90% mass loss at the end of experiment; however, PLA/5MgTT and PLA/5MgPEI exhibited the highest resistance to degradation, likely due to the protective effect of the surface modification induced by thermal treatment and polyethylenimine (PEI). Notably, these characteristics did not compromise the biocompatibility or osteogenic potential of the films, which remained comparable to the control samples when tested on human bone marrow multipotent mesenchymal/stromal cells. Full article

Magenta Cherry or Eugenia (Syzygium paniculatum Gaertn) is an underutilized berry species with an interesting source of functional components. This study aimed to evaluate these berries’ morphometric, nutritional, and phytochemical characteristics at two ripening stages, CM: consumer maturity (CM) and OM: over-maturity. Morphometric analysis revealed size and weight parameters comparable to commercial berries such as blueberries. Fresh fruits were processed into pulverized material, and in this, a proximate analysis was evaluated, showing high moisture content (88.9%), dietary fiber (3.56%), and protein (0.63%), with negligible fat, indicating suitability for low-calorie diets. Phytochemical screening by HPLC identified gallic acid, chlorogenic acid, hydroxycinnamic acid, ferulic acid, quercetin, rutin, and condensed tannins. Ethanol extracts showed stronger bioactive profiles than aqueous extracts, with significant antioxidant capacity (up to 803.40 µmol _Trolox/g via Ferric Reducing Antioxidant Power (FRAP assay). Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopic analyses established structural transformations of hydroxyl, carbonyl, and aromatic groups associated with ripening. These changes were supported by observed variations in anthocyanin and flavonoid contents, both higher at the CM stage. A notable pigment loss in OM fruits could be attributed to pH changes, oxidative degradation, enzymatic activity loss, and biotic stressors. Antioxidant assays (DPPH, ABTS, and FRAP) confirmed higher radical scavenging activity in CM-stage berries. Elemental analysis identified minerals such as potassium, calcium, magnesium, iron, and zinc, although in moderate concentrations. In summary, Syzygium paniculatum Gaertn fruit demonstrates considerable potential as a source of natural antioxidants and bioactive compounds. These findings advocate for greater exploration and sustainable use of this native berry species in functional food systems. Full article

Hybrid implants composed of magnesium and titanium are a promising direction in orthopaedics, as these implants combine the stability of titanium with the biological activity of magnesium. These partly soluble implants require careful investigation, as the degradation of magnesium releases hydrogen, which can enter the Ti matrix and thus alter the mechanical properties. To investigate this scenario and quantify the hydrogen uptake along with its structural impacts, we employed inert gas fusion, scanning electron microscopy, X-ray diffraction, and a combination of synchrotron absorption and X-ray diffraction tomography. These techniques enabled us to investigate the concentration and distribution of hydrogen and the formation of hydrides in the samples. Titanium hydride formation was observed in a region approximately 120 µm away from the titanium surface and correlates with the amount of absorbed hydrogen. We speculate that the degradation of magnesium at the magnesium/titanium implant interface leads to the penetration of hydrogen due to a combination of electrochemical and gaseous charging. Full article

Xylanase is an essential industrial enzyme for degrading plant biomass, pulp and paper, textiles, bio-scouring, food, animal feed, biorefinery, chemicals, and pharmaceutical industries. Despite its significant industrial importance, the extensive application of xylanase is hampered by high production costs and concerns regarding the safety of xylanase-producing microorganisms. The utilisation of renewable polymers for enzyme production is becoming a cost-effective alternative. Among the prospective candidates, non-pathogenic lactic acid bacteria (LAB) are promising for safe and eco-friendly applications. Our investigation revealed that Pediococcus pentosaceus G4, isolated from plant sources, is a notable producer of extracellular xylanase. Improving the production of extracellular xylanase is crucial for viable industrial applications. Therefore, the current study investigated the impact of various medium components and optimised the selected medium composition for extracellular xylanase production of P. pentosaceus G4 using Plackett–Burman Design (PBD) and Central Composite Design (CCD) statistical approaches. According to BPD analysis, 8 out of the 19 investigated factors (glucose, almond shell, peanut shell, walnut shell, malt extract, xylan, urea, and magnesium sulphate) demonstrated significant positive effects on extracellular xylanase production of P. pentosaceus G4. Among them, glucose, almond shells, peanut shells, urea, and magnesium sulphate were identified as the main medium components that significantly (p < 0.05) influenced the production of extracellular xylanase of P. pentosaceus G4. The optimal concentrations of glucose, almond shells, peanut shells, urea, and magnesium sulphate, as determined via CCD, were 26.87 g/L, 16 g/L, 30 g/L, 2.85 g/L, and 0.10 g/L, respectively. The optimised concentrations resulted in extracellular xylanase activity of 2.765 U/mg, which was similar to the predicted extracellular xylanase activity of 2.737 U/mg. The CCD-optimised medium yielded a 3.13-fold enhancement in specific extracellular xylanase activity and a 7.99-fold decrease in production costs compared to the commercial de Man, Rogosa and Sharpe medium, implying that the CCD-optimised medium is a cost-effective medium for extracellular xylanase production of P. pentosaceus G4. Moreover, this study demonstrated a positive correlation between extracellular xylanase production, growth, lactic acid production and the amount of sugar utilised, implying the multifaceted interactions of the physiological variables affecting extracellular xylanase production in P. pentosaceus G4. In conclusion, statistical methods are effective in rapidly assessing and optimising the medium composition to enhance extracellular xylanase production of P. pentosaceus G4. Furthermore, the findings of this study highlighted the potential of using LAB as a cost-effective producer of extracellular xylanase enzymes using optimised renewable polymers, offering insights into the future use of LAB in producing hemicellulolytic enzymes. Full article

Carboxylate (TCNF) and sulfonated (SCNC) cellulose nanofibers were synthesized and used as adsorbents for metallic cations in aqueous solutions: Na⁺ and Hg²⁺ (SCNC); Mg²⁺ and Hg²⁺ (TCNF). ICP-OES analysis of the liquid phase revealed metal removal efficiencies at room temperature of 89.3% (Hg²⁺) and 100% (Mg²⁺) for TCNF, 35.2% (Hg²⁺) and 63.3% (Na⁺) for SCNC after 3 h of contact. Interestingly, the nanofibers exhibited a distinct thermal degradation profile (characterized by two main events) compared to that of cellulose, suggesting that their nanostructured morphology and surface functionalization may enhance thermal instability. Additionally, the presence of metals at its surface notably altered the thermal degradation kinetics, as observed for mercury and magnesium in TCNF. Finally, the results for SCNC strongly suggest that the mechanism for thermal degradation can also change, as observed for mercury and sodium, expressed through the appearance of a new DTG peak located around 300 °C. Full article

Biodegradable magnesium alloys have emerged as promising alternatives to permanent metallic implants due to their unique combination of mechanical compatibility with bone and complete resorption, addressing the persistent issues of stress shielding and secondary removal surgeries. This review critically examines the historical development of magnesium-based biomaterials, highlighting advances in alloy design, manufacturing processes, and surface engineering that now enable tailored degradation and improved clinical performance. Drawing on recent clinical and preclinical studies, we summarize improvements in corrosion resistance, mechanical properties, and biocompatibility that have supported the clinical translation of magnesium alloys across a variety of orthopedic and emerging medical applications. However, challenges remain, including unpredictable in vivo degradation kinetics, limited long-term safety data, lack of standardized testing protocols, and ongoing regulatory uncertainties. We conclude that while magnesium-based biomaterials have advanced from experimental concepts to clinically validated solutions, further progress in personalized degradation control, real-time monitoring, and harmonized regulatory frameworks is needed to fully realize their transformative clinical potential. Full article

Magnesium (Mg) alloys have demonstrated tremendous potential in biomedical applications, emerging as promising metallic biomaterials due to their biocompatibility, degradability, and favorable mechanical properties. However, their practical implementation faces significant limitations stemming from mechanical performance degradation and premature fracture failure caused by complex physiological interactions, including flow erosion, corrosion fatigue, stress coupling effects, and dynamic wear under bodily conditions. Surface coating technology has been recognized as an effective strategy to prevent direct contact between magnesium substrates and corrosive media. This review systematically examines the fundamental degradation mechanisms of magnesium alloys in both vivo and vitro environments, presents recent advances in surface modification coatings for magnesium alloys, and critically analyses the interaction mechanisms between modified layers and electrolyte solutions. Special emphasis is placed on revealing the formation mechanisms, structural characteristics, and fracture behaviors of conversion coatings. Furthermore, the study discusses the current challenges in biomedical surface modification of magnesium alloys, proposes potential solutions to enhance their clinical applicability, and outlines future research directions to fully exploit the development potential of these advanced biomaterials. Full article

The aim of this study is to evaluate the effectiveness of deacidifying treatments for the restoration of textiles used as supports for works of art, with particular attention to the chemical stability, colour variation and mechanical resistance of the materials over time. The present study involved the analysis of two products: Bookkeeper^TM, containing magnesium oxide, and Nanorestore^TM, a dispersion of calcium hydroxide in alcoholic solutions of ethanol and 2-propanol. The products were applied to a series of tests on cotton, linen and jute fabrics. The experimental approach comprised an artificial degradation process of the fabrics, followed by the application of the treatments and an accelerated ageing cycle. A series of parameters were monitored throughout the experiment, encompassing surface pH, chromatic shifts ascertained through colorimetric measurements and the morphological transformations of the fabrics, as elucidated by scanning electron microscopy (SEM-EDS). The findings yielded from this study have enabled the delineation of the behaviour exhibited by the treated materials over an extended timeframe. This underscores the significance of a judicious selection of treatments, contingent upon the particular chemical and physical attributes inherent to the fabrics in question. Full article

The cointercalation of solvated Mg²⁺ ions into graphite has typically been considered challenging because of concerns regarding the instability of the electrolyte and the potential for structural degradation. However, recent developments in electrolyte design suggest that this process may be reversible under appropriate conditions. In this study, the interfacial behavior of graphite in a magnesium-ion system was investigated using in situ electrochemical atomic force microscopy. Electrochemical tests in a triglyme-based electrolyte revealed a reversible capacity of 158 mAh g⁻¹, attributed to the insertion of triglyme-solvated Mg²⁺ ions. Real-time surface imaging of highly oriented pyrolytic graphite revealed the formation of a passivating surface film during the initial cycle, along with nanoscale hill-like (~1 nm) and blister-like (~5 nm) structures, which were partially reversible and showed good correlation with the redox peaks observed in the cyclic voltammetry experiments, suggesting that the surface film enables Mg²⁺ transport while mitigating electrolyte decomposition. These findings demonstrate that stable co-intercalation of solvated Mg²⁺ ions is achievable in the early cycles in graphite and highlight the importance of interfacial engineering and solvation structures in the development of magnesium-ion batteries. Full article

Corrosion, combined with cyclic loading, is inevitable and becomes a challenging problem, even when inherently corrosion-protected materials have been selected and applied based on established in-house experience. Aero engine mount structures are exposed to dusty and salty environmental conditions during both operational and non-operational periods. It is becoming tough to predict the remaining useful corrosion fatigue life due to the unascertainable material strength degradations under service conditions. As such, a rationalized approach is currently being used to assess their structural integrity, which produces more wastages of the flying parts. This paper presents a novel approach for predicting corrosion fatigue by proposing a random-parameter model in combination with validated experimental data. The two-random-parameter model is employed here with the probability method to determine the time-independent corrosion fatigue life of a magnesium structural casting, which is used heavily in engine front-mount aircraft systems. This is also correlated with experimental data from the literature, validating the proposed stochastic corrosion fatigue model that addresses the technical variances that occur during service to increase optimal mount structure usage using an automated data system. Full article

Background and Objectives: Magnesium (Mg)-based materials, such as the WE43 alloy, show potential in biomedical applications owing to their advantageous mechanical properties and biodegradability; however, their quick corrosion rate and hydrogen release restrict their general clinical utilization. This study aimed to develop a novel Mg-Zn-Ca alloy system based on WE43 alloy, evaluating the influence of Zn and Ca additions on microstructure, mechanical properties, cytocompatibility, and electrochemical behavior for potential use in biodegradable orthopedic applications. Materials and Methods: The WE43-Zn-Ca alloy system was developed by alloying standard WE43 (Mg–Y–Zr–RE) with 1.5% Zn and Ca concentrations of 0.2% (WE43_0.2Ca alloy) and 0.3% (WE43_0.3Ca alloy). Microstructural analysis was performed utilizing scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS), while the chemical composition was validated through optical emission spectroscopy and X-ray diffraction (XRD). Mechanical properties were assessed through tribological tests. Electrochemical corrosion behavior was evaluated using potentiodynamic polarization in a 3.5% NaCl solution. Cytocompatibility was assessed in vitro on MG63 cells using cell viability assays (MTT). Results: Alloys WE43_0.2Ca and WE43_0.3Ca exhibited refined, homogeneous microstructures with grain sizes between 70 and 100 µm, without significant structural defects. Mechanical testing indicated reduced stiffness and an elastic modulus similar to human bone (19.2–20.3 GPa), lowering the risk of stress shielding. Cytocompatibility tests confirmed non-cytotoxic behavior for alloys WE43_0.2Ca and WE43_0.3Ca, with increased cell viability and unaffected cellular morphology. Conclusions: The study validates the potential of Mg-Zn-Ca alloys (especially WE43_0.3Ca) as biodegradable biomaterials for orthopedic implants due to their favorable combination of mechanical properties, corrosion resistance, and cytocompatibility. The optimization of these alloys contributed to obtaining an improved microstructure with a reduced degradation rate and a non-cytotoxic in vitro outcome, which supports efficient bone tissue regeneration and its integration into the body for complex biomedical applications. Full article

Magnesium-based biomaterials have emerged as highly promising candidates in the realm of biomedical engineering due to certain unique properties. However, their widespread application has been limited by a number of challenges, such as insufficient mechanical strength and rapid degradation rates. This study sought to advance the development of high-performance magnesium alloys by examining the microstructural evolution and associated strengthening mechanisms of Mg-Zn alloys modified with varying Nd contents. Comprehensive characterization techniques—including optical microscopy, XRD, and SEM/EDS—were employed to explain the influence of Nd additions on the microstructures. Mechanical performance was assessed through hardness testing, the RFDA method for elastic modulus, and tensile testing. The microstructural analysis of the as-cast Mg-Zn-Nd alloys revealed a complex phase composition comprising dendritic α-Mg, Mg₄₁Nd₅, and a Mg₃Nd binary phase enriched with rare earth elements. Notably, increasing the Nd content from 0.5% to 5% by weight resulted in a significant enhancement of hardness, reaching 59 HV compared to 42 HV in the base alloy. The tensile strength increased significantly from 62.9 MPa in the Mg-2.5Zn-0.5Nd alloy to 186.8 MPa in the Mg-2.5Zn-5Nd alloy. The elastic modulus values across all investigated alloys remained consistently comparable, which is expected as the elastic modulus is primarily determined by atomic bonding and is not significantly affected by alloying additions. These findings underscore the potential of Nd-alloyed Mg-Zn systems as viable, mechanically robust alternatives for next-generation biodegradable orthopedic implants. Full article