Search Results (600)

Biodegradable magnesium implants offer significant clinical promise, but their safe use requires reliable real-time in vivo monitoring of coating integrity. Existing methods lack sufficient sensitivity and temporal resolution to detect degradation at early stages, and there are no computational tools able to predict the success of a given sensor design before animal experiments. In the present paper, we present BioElectroSynth—a digital simulator of an implantable zero-resistance ammetry (ZRA) corrosion sensor in a mouse model. The simulator combines electrochemical noise, cardiac and muscular bioelectric interference, and instrumental limitations into a unified model, enabling virtual experiments, which mimic the complexity of the in vivo system. Using Monte Carlo analysis, we establish that a 2% breach in a chitosan coating on an AZ91 magnesium alloy electrode is statistically detectable from approximately 30 recordings of 30 s each, and quantify how electrode area, its location, sampling rate, and coating quality jointly determine detection sensitivity. The framework provides the first quantitative tool for predicting in vivo experiment feasibility from standard in vitro electrochemical data alone. By identifying instrument and design configurations that are statistically underpowered before any animal use, the approach directly supports the 3R principles of humane research. Full article

Magnesium (Mg) reinforced polylactic acid (PLA) composites have attracted increasing interest for orthopedic implants to solve the insufficient strength of PLA and to utilize the bioactive advantages of Mg ions in promoting bone formation. However, the weak interfacial adhesion between the Mg and PLA limits the applications of the composite. In this study, a dual interfacial enhancement approach was designed to combine surface fluorination with perforation. During hot pressing, molten PLA infiltrates the pores to form a ‘rivet-like’ mechanical interlocking. This structure significantly alters the load transfer and degradation behaviors of the composite. Compared to pure PLA, the dual treatment significantly elevated the bending strength by 49%, alongside an increase in the bending strain from 15% to 25%. Moreover, in vitro degradation tests revealed that this strategy suppresses H₂-induced delamination, and stabilizes both pH and Mg²⁺ release. Consequently, the bending strength remained at 86% after six weeks of in vitro degradation. In addition, the composite exhibits excellent biocompatibility, with MC3T3-E1 cell viability exceeding 90% in 100% extract. These results demonstrate that the reinforced Mg/PLA composite exhibits excellent mechanical properties, degradation stability, and biocompatibility, showing high potential for load-bearing orthopedic fixation applications. Full article

This study demonstrates the application of Laser-Induced Breakdown Spectroscopy (LIBS) for the elemental analysis of agricultural soils in South Punjab, Pakistan. Soil degradation due to intensive farming, imbalanced fertilizer use, and declining organic matter has reduced crop productivity in the region. To address this, rapid and accurate soil diagnostics are essential. LIBS, coupled with Calibration-Free analysis (CF-LIBS), was employed to quantitatively determine the concentrations of major and trace elements—including calcium, silicon, iron, aluminum, magnesium, titanium, potassium, sodium, lithium, and barium—without requiring chemical standards. Plasma characterization was performed using the Boltzmann plot method, yielding temperatures between 7750 and 9000 K, and electron number densities were derived from Stark-broadened spectral profiles. The results reveal significant spatial variability in elemental composition, reflecting differences in land use and irrigation sources. This work confirms LIBS as a versatile, efficient, and reliable tool for soil health assessment, offering a practical solution for monitoring soil nutrients and supporting sustainable agricultural management in resource-limited settings. Full article

Wetland ecosystems have been a central focus of ecological research for an quite some time. Nevertheless, the degradation of wetland riparian zones has markedly accelerated due to anthropogenic activities, climate change, and habitat heterogeneity. The objective of this paper is to investigate the differences in functional traits of riparian plants under changing wetland environments on a karst plateau, as well as to elucidate the adaptive strategies of wetland plants across different habitats. This study examines the Caohai Wetland located on the Guizhou karst plateau, selecting the leaves of four dominant plant species (Phragmites australis, Onopordum acanthium, Galium odoratum, Paspalum distichum) in the Caohai Wetland lakeshore zone and analyzes the influence of soil factors on the variation of plant functional traits within the wetland riparian zone. The results reveal that: (1) significant differences exist in the functional traits of dominant plants in the riparian zones of karst plateau wetlands, with complex interrelationships among these traits; (2) the coefficients of variation for magnesium (Mg) and calcium (Ca) in the soil are notably high (79.53% and 67.21%, respectively), whereas soil oxidation-reduction potential (ORP) exhibits the lowest coefficient of variation (4.36%)—furthermore, the convergent variation in specific leaf area (SLA) and leaf dry matter content (LDMC) directly reflects the strong environmental filtering imposed by this habitat—and (3) redundancy analysis (RDA) indicates that leaf length (LL), specific leaf area (SLA), leaf area (LA), and plant carbon content (PCC) are particularly sensitive to environmental changes, while soil calcium (Ca), total nitrogen (TN), water-dispersible clay (WDR), soil organic matter (SOM), soil moisture content (SPMC), and total potassium (TK) constitute the principal soil factors influencing plant adaptive strategies in karst plateau wetlands. In conclusion, this study demonstrates that adaptation to karst wetland habitats is mediated through trade-offs in the allocation of photosynthetic products and the regulation of carbon (C), nitrogen (N), and phosphorus (P) nutrient balances under calcium-enriched and phosphorus-limited conditions, thereby reflecting the response characteristics of functional traits in karst plateau wetland plants to environmental changes. Full article

In this study, niobium/zirconium dioxide/hydroxyapatite (Nb/ZrO₂/HA) composite coating was deposited on ZK60 magnesium alloy by the plasma spraying technique. The effects of spraying power and the powder feeding rate on the surface morphology, corrosion resistance, surface hardness, and surface roughness were investigated in this study. Tests were conducted through the optimal parameter combination obtained during the optimization process. The Nb/ZrO₂/HA coating consisted of α/β-TCP, TTCP, Nb₂O₅, HA, Nb, and t-ZrO₂ phases. The results suggest that the Ca/P ratio of the coating approached the ideal calcium-to-phosphorus ratio characteristic of bone implant material surfaces. Under the parameters of 33 kw and 18 g/min, the coating exhibited a dense, flattened morphology with significantly reduced roughness of Ra = 2.128 μm. Compared to the pure HA coating, the surface hardness and corrosion resistance of the Nb/ZrO₂/HA-coated sample increased by 28% and 56%, respectively. Furthermore, the mass loss rate in simulated body fluid (SBF) was considerably decreased by 33% compared to the HA coating. In vitro cytotoxicity assay reveals that the cell proliferation activity of the Nb/ZrO₂/HA composite coating was higher than that of the HA/ZrO₂ composite coating and the HA coating. Hence, the composite coating possessed favorable degradation controllability and biocompatibility. Full article

Bone tissue plays a vital role in the human body and possesses intrinsic self-repair mechanisms; however, large defects or pathological fractures may exceed its natural healing capacity. Bone tissue engineering provides promising strategies to restore bone integrity through the use of scaffolds, growth factors, and stem cells. While calcium phosphate (CaP)-based ceramics, such as hydroxyapatite (HAp) and tricalcium phosphate (TCP), represent the current benchmark, their limitations, including slow degradation (HAp) and limited osteoinductivity (TCP), have driven the development of alternative biomaterials. In this context, magnesium phosphate (MgP)-based materials have gained increasing attention due to their tunable resorption rate, improved biodegradability, and ability to stimulate osteogenesis and angiogenesis through the release of magnesium (Mg²⁺) ions. This study reports on composite scaffolds based on electrospun poly(ε-caprolactone) (PCL) fibres coated with MgP layers doped with lithium (Li) and zinc (Zn), designed to mimic the nanofibrous architecture of the extracellular matrix. Lithium and zinc were selected due to their known ability to modulate cellular response, with lithium promoting osteogenic activity and zinc contributing to improved cell proliferation and antibacterial potential. The phosphate phases obtained by coprecipitation were deposited onto the PCL fibres using Matrix-Assisted Pulsed Laser Evaporation (MAPLE), enabling controlled surface functionalization. Following thermal treatment, the formation of the crystalline magnesium pyrophosphate (Mg₂P₂O₇) phase was confirmed by chemical and structural characterization. The combination of a slowly degrading PCL matrix, providing sustained structural support, and a bioactive MgP coating, enabling rapid and controlled ion release, results in improved scaffold performance in terms of biocompatibility, biodegradability, and bioactivity. While the slow degradation rate of PCL ensures mechanical stability over an extended period, the surface-deposited MgP phase allows immediate interaction with the biological environment, facilitating faster ion release and enhancing cell–material interactions. These findings highlight the potential of the developed composites as promising candidates for trabecular bone regeneration and as viable alternatives to conventional CaP-based scaffolds in regenerative medicine. Full article

Magnesium alloys are promising materials for orthopedic applications due to their biodegradability and mechanical properties compatible with bone. However, their rapid degradation in physiological environments limits clinical use. In this study, WE43B magnesium alloy was coated with a PEO layer followed by a P(L/G/TMC) polymer applied via ultrasonic spraying. The influence of polymer layer number (10, 20, 30) on coating properties was systematically investigated. Scanning electron microscopy (SEM) analysis revealed an approximately fourfold reduction in porosity after polymer deposition, with progressive pore filling at higher layer numbers, while Fourier transform infrared spectroscopy (FT-IR) mapping indicated uniform polymer coverage. Compared to PEO alone, polymer-modified samples exhibited an approximately 7-fold increase in water contact angle, a ~50% reduction in surface roughness, and improved adhesion. Degradation-related analyses, including ion release, post-immersion SEM, and scanning acoustic microscopy (SAM), indicated that increasing polymer thickness effectively limited degradation processes. Ion release decreased by ~40–50% for the 30-layer coating compared to PEO, with the most pronounced reduction observed between the uncoated PEO and polymer-modified samples. These results demonstrate that the number of polymer layers plays a key role in controlling the barrier properties and stability of hybrid PEO/polymer coatings under simulated physiological conditions. Full article

Background/Objectives: Biodegradable magnesium (Mg)-based biomaterials release Mg²⁺ ions during degradation and may promote vascular-related regeneration. However, their effects on lymphatic endothelial cells (LECs) and lymphangiogenesis remain unclear. This study investigated whether magnesium powder-derived ionic extracts could enhance lymphangiogenesis-related behaviors of LECs in vitro. Methods: Mg powder extracts were prepared and diluted for in vitro treatment. After viability screening, Mg (1:10), Mg (1:100), and Mg (1:1000) were selected for further analysis. LEC proliferation, migration, and tube formation were assessed, together with intracellular reactive oxygen species (ROS) levels and the expression of VEGFA, VEGFC, and VEGFR3. Results: Mg (1:10) and Mg (1:100) showed good cytocompatibility and significantly promoted LEC proliferation, migration, and tube formation compared with the control and Mg (1:1000) groups. These effects were accompanied by reduced intracellular ROS levels and increased expression of VEGFA, VEGFC, and VEGFR3. Conclusions: Magnesium powder-derived ionic extracts enhance lymphangiogenesis-related responses of LECs in vitro, particularly at the 1:10 and 1:100 dilutions. These findings support the potential of Mg-based biodegradable biomaterials for lymphatic tissue regeneration. Full article

Conventional electrochemical evaluation methods in liquid electrolytes often do not accurately replicate in vivo degradation processes, thereby posing a significant challenge in translating biodegradable magnesium-based materials from laboratory research to practical use. To address this challenge, we have developed a new in vitro analysis method using a chitosan/glycerol/Ringer’s gel that closely resembles biological tissue in terms of elemental composition and three-dimensional structure. We examined the degradation of the AZ31 magnesium alloy in both Ringer’s solution and the gel electrolyte using potentiodynamic polarization and periodic surface morphology imaging. Our results indicate that the corrosion rates and morphological features obtained from the gel electrolyte better correspond to in vivo data from animal studies, suggesting that the method can be used to accurately evaluate the corrosion resistance of magnesium alloys in vivo. Full article

This study investigates the dual mechanisms by which SiO₂ deteriorates magnesium phosphate cement (MPC) performance. MgO-SiO₂ clinkers were prepared using lightly calcined magnesia (MgO) with SiO₂ additions ranging from 1% to 9%, followed by calcination at temperatures between 1100 °C and 1500 °C. Through XRD–Rietveld refinement, workability, compressive strength, and hydration heat analyses, the damaging effects of SiO₂ were systematically evaluated. Results reveal that SiO₂ degrades MPC through two concurrent mechanisms: chemical consumption and physical deactivation of reactive MgO. Chemically, SiO₂ reacts with MgO during calcination to form inert forsterite (Mg₂SiO₄), irreversibly reducing reactive MgO content. Physically, SiO₂ and its reaction products lower the crystallinity and reactivity of remaining MgO while diluting reactive components. A calcination temperature of 1200 °C was optimal, yielding the highest compressive strength (3 d strength > 30 MPa). Increasing SiO₂ dosage monotonically reduced strength; at 1200 °C, 9% SiO₂ reduced 3 d strength by ~40% compared to 1%. Hydration heat analysis showed that both heat flow rate and cumulative heat release increased with SiO₂ content due to enhanced heterogeneous nucleation from Mg₂SiO₄. Critically, this increased heat output did not translate into higher strength, indicating that microstructural quality—not reaction extent—governs mechanical performance. Rietveld quantification confirmed that Mg₂SiO₄ formation increased linearly with SiO₂ dosage and temperature (reaching 72.24% at 1500 °C with 9% SiO₂), providing the material basis for dual damage. This work offers mechanistic insights and experimental support for utilizing low-grade magnesite and optimizing MPC performance. Full article

Thermochemical heat storage technology serves as an effective approach for efficient recovery and cross-seasonal storage of low-grade waste heat. However, traditional packed-bed heat exchange methods in industrial applications are prone to material contamination and performance degradation due to impurities in waste heat gases. To address this, this study proposes and constructs a thermochemical heat storage system based on moving-bed indirect heat exchange, using magnesium sulfate heptahydrate (MgSO₄·7H₂O) as the heat storage medium. The system investigates its desorption and heat storage characteristics within the moving bed. A small-scale moving-bed experimental platform was established, incorporating a vacuum-assisted system to promptly remove water vapor generated during desorption. The experimental system examines the effects of different operating parameters (e.g., inlet water temperature and flow rate) on particle temperature fields, desorption rates, and overall heat transfer performance. Results demonstrate that MgSO₄·7H₂O exhibits excellent heat storage stability and reaction controllability in the medium-low temperature range (60–95 °C). Increasing inlet water temperature and flow rate enhances desorption processes, but high temperatures also lead to increased temperature gradients, reducing waste heat recovery rates. Practical applications require optimizing the balance between heat transfer enhancement and desorption time. Compared to conventional heat storage particles, the moving-bed system using magnesium sulfate heptahydrate achieves approximately 30% higher overall heat transfer coefficient. Compared to traditional packed beds, the moving-bed heat exchange method demonstrates superior heat transfer uniformity and storage efficiency. This study validates the feasibility of the “moving-bed + thermochemical heat storage + vacuum desorption” technology under non-clean heat source conditions, providing experimental evidence and technical references for efficient industrial waste heat recovery and high-density storage. Full article

This study evaluates the impact of four drying methods—open sun drying, solar drying, infrared drying, and microwave drying—on the quality attributes and elemental retention of apricots (Prunus armeniaca L.). Experimental trials were conducted in June 2024 at the Tashkent Institute of Chemical-Technology using equal quantities of fresh apricots. Drying was continued until the moisture content, measured gravimetrically, dropped below 20% (wet basis), followed by spectroscopic analysis to determine macro- and microelement concentrations. Solar-dried apricots showed higher retention of essential nutrients in this experimental trial: potassium (2.37%), silicon (0.538%), magnesium (0.145%), calcium (0.176%), and sulfur (0.152%). In contrast, open sun drying led to significant nutrient degradation and poor visual quality. Microwave drying preserved some micronutrients but resulted in surface scorching due to uneven heating. Infrared drying yielded acceptable results but required substantial energy input. Among all methods, solar drying provided the optimal balance of high product quality and energy efficiency. The drying process required negligible electrical energy owing to exclusive reliance on solar radiation. This method supports sustainable food processing by reducing energy demand and greenhouse gas emissions while preserving nutritional quality. The results highlight solar drying as a promising, eco-friendly technique for preserving the nutritional integrity of agricultural products. These findings offer valuable scientific guidance for selecting appropriate drying technologies in the food processing industry, especially in regions with high solar potential. However, the study is limited to a single fruit variety and seasonal conditions. Full article

The present study examines the physicochemical degradation and elemental contamination of marine distillate diesel fuels, which were stored in land-based tanks in operational conditions. Forty-one (41) samples, in compliance with ELOT ISO 8217:2024 were analyzed for crucial physicochemical properties. Stepwise regression identified magnesium (Mg) (positive) and chromium (Cr) (negative) as significant viscosity predictors (R² = 0.269, p = 0.003, VIF < 2), while calcium (Ca), Phosphorus (P), zinc (Zn), copper (Cu), lead (Pb) and Ferrous (Fe) were excluded due to multicollinearity. Strong correlations (r > 0.85) between element pairs (Cu-Pb) (r = 0.996), Ca-Zn (r = 0.897), and P-Ca (r = 0.888) indicate common sources from lubricant additives (ZDDP) and brass corrosion, with individual correlations recorded for Ca (showing r = 0.679, p < 0.001), P (r = 0.722, p < 0.001), and Zn (r = 0.595, p < 0.001). The results revealed that fuels stored in carbon steel tanks under high-humidity conditions for over six (6) months recorded higher metal loads than those in stainless steel tanks with regular periodic supply. The FAME content in the studied samples ranged from 6.7 to 7.1% v/v and showed no significant correlation with degradation indicators (p > 0.05). The narrow FAME range examined precludes definitive conclusions regarding specific biodiesel effects. The threshold of 0.2 mg/kg, as set by manufacturers’ guidelines to protect injectors, was exceeded in the coastal carbon steel tank samples with eight (8) months of storage under high-humidity conditions and in the coastal carbon steel tank samples with nine (9) months of storage under high-humidity conditions examined. The current study offers a systematic correlation between viscosity and elemental contamination for marine distillate fuels under operational storage conditions regarding real-world samples. Full article

Soil degradation remains a major challenge in sub-Saharan Africa, particularly within smallholder farming systems characterized by low-input agriculture and unsustainable land use practices. Sustainable agriculture production requires a good understanding of soil characteristics across diverse farming contexts. This study assessed soil health and microbial diversity across three contrasting systems: long-term fallow (aggregated farm A), high-input (aggregated farm B), and conventional smallholder (non-aggregated farm C) farms experiencing declining productivity. Soil samples collected from the three contrasting systems were analyzed for physicochemical properties and microbial communities using high-throughput DNA sequencing. Microbial communities were characterized by using amplicon sequencing targeting bacterial 16S rRNA and fungal ITS gene regions, allowing taxonomic profiling and inference of microbial diversity patterns. The two aggregated farms predominantly had clay soils, with pH values ranging from 6.78 to 7.39 and organic carbon content from 1.17% to 1.64%. In contrast, conventional farms had loamy to clayey soils with a pH value of 5.88 and an organic carbon content of 1.25%. Both types of aggregated farms showed moderate to high concentrations of total nitrogen (0.12–0.13%), phosphorus (38.79–151.36 mg/kg), and potassium (548.84–943.52 mg/kg), along with elevated levels of calcium and magnesium, though fertilizer application was inconsistent across the sites. Microbial diversity analysis revealed significant differences among the systems. The dominant bacterial phyla were Pseudomonadota (48.5%), Acidobacteriota (34.2%) and Actinomycetota (19.6%), while the primary fungi included Ascomycota, Basidiomycota and Mortierellomycota. Functional profiling using COG and KEGG databases showed distinct variations in microbial potentials, with a high diversity of Actinobacteria, Acidobacteria and Proteobacteria. Functional profiles inferred from amplicon-based predictions represent potential metabolic capabilities and should be interpreted cautiously as indicative rather than direct functional gene quantification. Correlation analyses between soil and microbial communities provided essential baseline data to support the development of sustainable farming practices and land restoration strategies aimed at improving soil fertility and agricultural productivity in these degraded landscapes. Full article

Marine concrete is often exposed to multiple aggressive ions, so mechanical deterioration cannot be reliably interpreted using single-ion durability concepts. This study investigates ocean-oriented concretes incorporating high contents of mineral admixtures under coupled sulfate/chloride/carbonate/magnesium actions and develops a pore-structure-based D–P dual-parameter framework linking microstructural descriptors to macroscopic peak stress and peak strain. Three binder systems were designed: ordinary Portland cement concrete (OPC), cement–silica fume concrete (CSC, 20% silica fume), and cement–silica fume–fly ash concrete (CSFC, 20% silica fume + 50% fly ash). Specimens were immersed for 12 and 24 months in four representative binary-salt solutions. Porosity evolution and pore-size-class distributions were quantified by low-field NMR, while pore complexity was characterized using multi-scale fractal dimensions. The results show that mineral admixtures generally refine the pore system and improve the integrity of fine pores; CSFC exhibits the most robust microstructural stability across the tested environments, whereas CSC shows a pronounced degradation of fine-pore structure under CE4. A second-order response surface model built on Z-score normalized fractal dimension (D) and porosity (P) achieves reliable predictability for peak strain (R² = 0.85) and peak stress (R² = 0.79). Global Sobol sensitivity analysis reveals distinct controlling mechanisms: peak strain is predominantly governed by porosity (S_P = 85.9%), whereas peak stress is controlled by the combined effects of porosity, pore complexity, and their interaction (S_P = 42.4%, S_D = 19.8%, S_{D × P} = 37.8%). Local sensitivity mapping further identifies high-sensitivity regimes at extreme pore states, providing mechanistic guidance for mixture optimization. Overall, the proposed D–P framework quantitatively bridges pore volume/geometry evolution and mechanical degradation, offering a practical predictive tool for durability-oriented design of marine concretes under multi-ionic attack. Full article