Search Results (2,046)

This study investigates the synthesis–structure relationships governing sol–gel-derived nanostructured MgFe₂O₄ ferrite powders for high-temperature thermochemical energy conversion applications. The effects of key processing parameters, including propylene oxide (PO) concentration, gel aging time, calcination temperature, and calcination duration, were systematically examined to tune the phase composition, specific surface area (SSA), pore volume, crystallite size, and nanoparticle morphology of MgFe₂O₄. Increasing the PO concentration from 5 to 20 mL shortened the gelation time from 585 to 323 s and increased the SSA from 5.30 to 17.88 m²/g, while the pore volume increased from 0.0074 to 0.0210 cm³/g. In contrast, gel aging time between 24 and 120 h produced negligible changes in SSA, pore volume, and crystallite size, indicating that extended aging is not required for microstructural control. Calcination temperature strongly influenced the nanostructure: increasing the temperature from 600 to 1000 °C decreased SSA and pore volume while increasing crystallite size from 21.33 to 48.76 nm. Longer calcination times produced a similar but less pronounced effect, decreasing SSA from 18.83 to 14.89 m²/g and increasing crystallite size from 17.55 to 30.12 nm. Overall, phase-pure MgFe₂O₄ with favorable textural properties was obtained using 20 mL of PO, 24 h of aging, and calcination in the 700–800 °C range. Under the identified synthesis conditions, namely 20 mL of PO, 24 h of aging, and calcination in the range of 700–800 °C for 2 h, phase-pure MgFe₂O₄ nanoparticles with particle sizes of approximately 10–50 nm were obtained. These results establish a processing–microstructure framework for engineering MgFe₂O₄ nanomaterials with tunable textural properties for solar thermochemical redox cycles and related high-temperature energy applications. Full article

To support the achievement of the carbon peaking and carbon neutrality goals and promote the resource utilization of industrial solid waste, a ternary solid waste composite cementitious material was prepared by blending ground granulated blast-furnace slag (GGBFS), fly ash (FA), and carbide slag (CS) with cement. The optimal mix ratio was determined through single-factor experiments and response surface methodology. The synergistic hydration mechanism was elucidated using microstructural characterization techniques, including XRD, FTIR, TG-DTG, and SEM. The composite material was then applied to a semirigid base course, and its mechanical properties and durability were systematically evaluated. The results indicate that the optimal levels of FA, GGBFS, and CS investigated in the single-factor experiments are 20–40%, 30–50%, and 2–6%, respectively. The optimal mix ratio of the ternary solid waste composite is 21.0% FA, 36.3% GGBFS, and 5.7% CS. The underlying microstructural mechanism is that carbide slag creates a highly alkaline environment, which activates the pozzolanic activity of GGBFS and fly ash, leading to the formation of hydration products dominated by C-(A)-S-H gel. With increasing curing age, the gel structure evolves from a loose and disordered state to a dense and ordered state, ultimately forming a compact microstructure based on a highly polymerized C-(A)-S-H gel matrix. The 7-day unconfined compressive strength of the stabilized gravel using the solid waste-based composite cementitious material reached 5.93 MPa, and the 28-day drying shrinkage coefficient was reduced by 18.3% compared with that of cement-stabilized gravel. After 18 freeze–thaw cycles, the compressive strength increased by 2.4%, with the pore structure characterized by a “macropores decreasing, micropores increasing” refinement pattern. After 18 wetting–drying cycles, the cumulative strength loss was 11.26%, outperforming cement-stabilized gravel. Combined with SEM observations, these performance improvements are attributed to the densely intertwined hydration products, particularly C-S-H gel, which effectively fill the voids between aggregate particles and significantly enhance the volume stability, freeze–thaw resistance, and wetting–drying durability of the stabilized gravel. The application of this cementitious material in a semirigid base course demonstrates excellent mechanical and durability properties, providing a theoretical basis and technical support for the widespread application of industrial solid waste in road engineering. Full article

This study experimentally investigated the stabilization mechanisms and structure formation models of high-water-content soft soils (>70%) treated with ordinary Portland cement, sulfur aluminate cement, gypsum, and lime. Fifteen single- and composite-stabilizer systems were evaluated using unconfined compressive strength (UCS) tests and microstructural analyses, including SEM, XRD, TG–DTG, and FTIR analyses. The results show that stabilized soils containing cementitious components exhibit significantly higher strength due to the formation of calcium silicate hydrate (C–S–H) gel, which effectively binds soil particles. The addition of sulfur aluminate cement, gypsum, and lime promotes rapid hydration and generates abundant ettringite (AFt) crystals with strong water absorption capacity, contributing to early strength development. Based on these findings, a composite stabilizer (ECS) combining cement with appropriate proportions of sulfur aluminate cement, gypsum, and lime is proposed, achieving substantial improvements in both early and long-term strength. The stabilization process proceeds in two stages: rapid AFt formation absorbs free water and fills large pores to form a three-dimensional network, and then C–S–H gel cementation integrates the soil–AFt framework into a dense and coherent structure. The study provides mechanistic insight and a theoretical basis for stabilizing high-water-content soft soils in coastal and riparian engineering applications. Full article

Offshore high-temperature steam flooding suffers severe steam channeling, uneven steam intake and low thermal efficiency, while conventional profile control agents fail to adapt to coupled harsh environments of 200–350 °C high temperature, ultra-high salinity and continuous steam shear. Existing reviews mainly focus on onshore thermal reservoirs or single foam/gel materials, lacking a targeted, gel-oriented systematic review matching unique offshore platform constraints. Guided by the integrated framework of “flow control–diversion–enhanced sweep efficiency”, this work establishes a six-dimensional quantitative screening standard and unified performance comparison database to systematically review foam, gel, particle, thermo-responsive and composite profile control systems. Differing from petroleum engineering-oriented summaries, this paper subdivides high-temperature gels into six categories from a polymer material perspective, elaborating their crosslinking mechanisms, thermal rheology and cyclic steam degradation rules; the inherent advantages, limitations and offshore applicable boundaries of each medium are quantitatively compared, with special emphasis on the unique “deep migration followed by in situ thermal activation” mechanism of thermo-responsive materials. Composite systems relieve single-material defects via multi-mechanism synergy yet face complicated on-site deployment barriers. Three core bottlenecks restricting field application are identified: the irreconcilable trade-off between deep propagation and stable plugging, large deviation between static aging results and dynamic anti-scouring performance, and exclusive engineering limitations of offshore platforms. A dedicated standardized dynamic laboratory evaluation scheme for cyclic steam flooding is proposed to narrow lab-field performance gaps. Future research priorities include salt-resistant thermally responsive composite gel modification, low-cost multi-component compound formula optimization, unified dynamic evaluation criteria and staged material matching guidelines to realize balanced performance of high-temperature tolerance, deep delivery and offshore operability. Full article

Background/Objectives: Micro- and nano-scale hydrogels (microgels and nanogels) have attracted increasing attention as carriers for drug delivery due to their high-water content, responsiveness to external stimuli, tunable properties, and versatility. In this work, gelatin methacryloyl (GelMA) with a medium degree of methacryloylation (DoM ca. 60%) was ad hoc synthesized as a constituent material for nanogel production. For the first time in the literature, GelMA-based nanogels (nanoGelMA) were developed through an optimized two-step desolvation method combined with photo-crosslinking. Methods: The influence of key process parameters, including the pH, volume of desolvating agent, photo-initiator concentration, and UV exposure time, was systematically investigated to identify optimal conditions for nanoGelMA preparation. To assess its potential as a drug delivery nanocarrier, the nanoGelMA was loaded with ibuprofen (IBU) as a model anti-inflammatory drug via in situ encapsulation during nanogel preparation. Results: The formulated nanoGelMA exhibited an average hydrodynamic diameter (d) of ca. 250 nm, a polydispersity index of 0.2, and a production yield of approximately 30%. The nanogels demonstrated stability in water and in phosphate buffer at pH 5 over 96 h, while exhibiting significant swelling in physiological-like conditions and enzymatic degradation (d of ca. 421 ± 91 nm and 609 ± 182 nm at 96 h, respectively). The cytocompatibility evaluation demonstrated high cell viability (86–96%) of the nanoGelMA at different concentrations (1–5 mg/mL). IBU-loaded nanoGelMA particles were successfully developed via direct drug encapsulation during nanogel formation, achieving a maximum encapsulation efficiency of ca. 30%, and exhibited environment-responsive release, with kinetics modulated by the ionic strength, pH, and enzymatic activity. Conclusions: Overall, the nanoGelMA developed herein represents a promising nanogel platform with great potential for the development of advanced and controlled drug delivery therapies. Full article

To comparatively evaluate the shear behavior of controlled low-strength materials (CLSM) prepared from different local soil sources, three representative soils from the Yellow River alluvial plain, namely, silt, silty clay, and sand, were used to prepare CLSM with a cement–slag–fly ash–gypsum blended cementitious binder. Triaxial shear tests and scanning electron microscopy (SEM) observations were conducted to compare the failure modes, stress–strain responses, strength characteristics, and hardened microstructures of the three CLSM types under different binder contents and confining pressures. The specimens generally exhibited inclined shear planes, conjugate shear planes, vertical cracks, and plastic bulging. Their stress–strain responses could generally be divided into four stages: linear elastic deformation, plastic yielding, strain softening, and residual stabilization. Within the tested binder-content ranges, the peak strength generally followed the order of sand-based CLSM > silt-based CLSM > silty clay-based CLSM. On average, the residual strength retained approximately 75% of the peak strength. The failure stress states of the tested CLSM could be reasonably represented by the Mohr–Coulomb criterion within the investigated confining-pressure range, and preliminary empirical relationships were established within the tested ranges to estimate peak strength, residual strength, and shear strength parameters. SEM observations suggested that C–S–H-like gel and needle-like products appeared to fill pores and form cemented connections between soil particles, providing a possible qualitative interpretation of the macroscopic strength differences among the three CLSM types. These findings provide a basis for shear strength evaluation and the mix design of CLSM prepared from Yellow River alluvial soils. Full article

While bacterial skin infections are highly prevalent worldwide, their eradication with conventional topical medications remains highly challenging. Cinnamic acid (CA) is a naturally occurring molecule with interesting antibacterial properties, but its efficacy is hindered by poor aqueous solubility and skin permeability. To overcome these challenges, CA was encapsulated within novasomes, which are multilamellar vesicles composed of fatty acids, cholesterol, and nonionic surfactants. The novasomes were optimized using a 2³ factorial design and the optimized formulation was incorporated in a carbopol gel base and evaluated for spreadability, rheological properties, drug release, ex vivo skin permeation and deposition, and antibacterial efficacy. The optimized novasomes featured desirable properties, including high drug entrapment (94.75 ± 0.05%), nanometric particle size (123.80 ± 1.44 nm), and negative zeta potential (−36.63 ± 0.61 mV). CA novasomal gel exhibited shear-thinning behavior, coupled with thixotropic properties. It also achieved approximately 1.7-fold higher flux through rat skin compared with the free CA gel. Moreover, the novasomes showed a two-fold reduction in the minimum inhibitory concentration of the drug against E. coli compared with the drug suspension. These findings support the potential of CA novasomal gel to enhance its antibacterial activity and skin permeability, making it a promising approach for topical delivery of this naturally occurring compound. Full article

Hot-pressed peanut protein isolate (HPPI), severely denatured during oil extraction, exhibits limited interfacial functionality, restricting its application in structured emulsions. In this study, high-voltage pulsed electric field (PEF) was employed to modulate the structural and interfacial properties of HPPI, a sustainable food biopolymer. PEF treatment induced conformational rearrangement, including a shift in secondary structure from α-helix to β-sheet and increased exposure of hydrophobic residues. These structural changes reduced particle size and increased surface charge, with optimal modification at 2.5 kV/cm. Consequently, interfacial activity was significantly improved, as evidenced by decreased interfacial tension and increased dilatational modulus, indicating a more elastic interfacial film was formed. The modified protein (2.5 kV/cm) effectively stabilized high internal phase emulsions (HIPEs) with typical gel-like viscoelastic features, achieving optimal stability at 2.0 wt% protein concentration, 75% oil phase fraction, and NaCl concentrations below 100 mM. Overall, PEF treatment enhances the interfacial functionality of HPPI by modulating its structure and interfacial film properties, thereby facilitating the fabrication of biopolymer-based food-grade HIPEs for practical food applications. Full article

Background/Objectives: Antibiotics are commonly used for acne treatment. However, increasing bacterial resistance has prompted interest in natural antimicrobial agents, such as thymol (THY), as alternative therapies. This study investigated the effectiveness of Leciplex cationic nanovesicles encapsulating thymol (LPX-THY) as a promising topical acne management strategy. Methods: Leciplex nanovesicles were assembled using soy phosphatidylcholine (SPC) and cationic surfactants and characterized in terms of particle size, zeta potential, entrapment efficiency, morphology, in vitro release, and ex vivo skin permeation. The optimized formulation was subsequently incorporated into Carbopol/HPMC gel base and evaluated in terms of viscosity, in vitro release, ex vivo skin permeation, in vitro antimicrobial study, and in vivo assessment in a rat model. Results: Optimal THY-LPX nanovesicles made of SPC and Dimethyldidodecylammonium bromide DDAB in a 1:1 molar ratio showed circular outline with particle size, zeta potential, and entrapment efficiency of 187.7 ± 1.78 nm, 36.97 ±0.21 mV, and 60.5 ± 2.3%, respectively. THY-LPX gel demonstrated minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at a concentration of 156.25 µg·mL⁻¹ against Staphylococcus aureus, a clear absence of biofilm coating under SEM, and substantial red fluorescence, indicating reduction in viable bacteria under a confocal laser microscope. In vivo study showed enhanced anti-inflammatory effect evidenced by substantial ear skin thickness reduction; 72.7% for THY-LPX gel-treated rats compared to 41.7% and 20% for THY gel and blank LPX gel-treated groups, respectively. Histopathological investigation further confirmed reduced inflammatory response in rats treated with optimized THY-LPX gel. Conclusions: The developed THY-LPX gel serves as a potential topical delivery platform of THY for acne therapy. Full article

The growing volume of industrial waste and the need for sustainable material solutions drive the search for cost-effective fillers and energy-efficient processing methods for polymer composites. This study investigates the valorization of brick dust (BD), a fine ceramic waste, as a reinforcing filler for unsaturated polyester resin (UPR), combined with microwave (MW) treatment applied at different stages of composite fabrication. The brick dust was comprehensively characterized using laser diffraction, SEM, EDX, XRD, and FTIR, revealing an environmentally safe aluminosilicate powder with a mean particle size of 3–6 µm, plate-like morphology, and surface hydroxyl groups favorable for matrix interaction. The optimal filler content was found to be 50 phr, which increased flexural strength by 6.5%, flexural modulus by 134%, tensile strength by 11%, and impact strength by 40% compared to neat UPR. Among the MW strategies evaluated, post-curing of the fully polymerized composite for 120 s proved most effective, yielding further improvements in flexural strength (110 MPa, +34.1%), flexural modulus (8250 MPa, +49.7%), impact strength (13.8 kJ/m², +119%), and Shore D hardness (88). MW post-curing also increased the gel fraction from 95.0% to 97.8%, raised the thermal stability index (THRI) from 150.6 to 165.8, and reduced equilibrium water absorption from 0.62% to 0.47% with a reversibility index of 87.5%. Fracture surface analysis confirmed a transition from interfacial debonding to cohesive matrix failure, with ultra-thin polymeric veils replicating the scaly filler structure. These results demonstrate that microwave post-curing synergistically enhances the mechanical, thermal, and moisture-resistant properties of brick dust-filled polyester composites. Full article

Background/Objectives: We aimed to conduct a comprehensive assessment of how transient iatrogenic hypothyroidism, induced for diagnostic purposes during the follow up of patients with differentiated thyroid cancer, impacts both quantitative and qualitative lipid parameters. Methods: Blood samples were collected during continuous levothyroxine (LT4) supplementation and after four weeks of LT4 withdrawal. In addition to thyroid hormone levels and routine lipid parameters, LDL and HDL subfractions were analyzed using polyacrylamide gel electrophoresis (Lipoprint). Furthermore, the activities of HDL-associated human paraoxonase-1 (PON1) paraoxonase and arylesterase were measured spectrophotometrically, while the levels of myeloperoxidase and apolipoprotein M (ApoM) were determined using ELISA. The activity of key regulators in HDL remodeling was measured using activity assay kits. Results: In this prospective, single-center study, a total of 52 patients were enrolled (mean age 48 ± 15 years; 13 males and 39 females). Compared to values measured during continuous LT4 supplementation, total cholesterol, HDL-C, LDL-C, ApoA1, and ApoB100 levels were significantly elevated during iatrogenic hypothyroidism (p < 0.0001 for all parameters). Differences in lipoprotein subfraction patterns were also observed: in hypothyroidism, the mean LDL particle size decreased (p = 0.0007) and the proportion of HDL subfractions shifted to the larger HDL subfractions (p < 0.0001). The paraoxonase activity and ApoM level tended to be increased (p = 0.030 and p = 0.011, respectively). Conclusions: In short-term overt hypothyroidism, opposing changes were observed: the shift toward smaller, denser LDL subfractions is considered atherogenic, whereas the increased proportion of larger HDL subfractions, the trend for higher paraoxonase activity and apoM levels can be potentially anti-atherogenic. Our findings further characterize the functional alterations of lipoproteins in hypothyroidism. Full article

Perovskite manganites (AMnO₃) and perovskite-like manganites (A′_1−xA_xMnO₃) are complex oxide materials that have attracted significant attention from the scientific community in recent years due to their structural flexibility, mixed-valence state, tunable electronic configuration, and multifunctional properties. This review systematically analyzes the synthesis methods, structural classification, and physicochemical characterization of perovskite manganites, as well as their magnetic, optical, electrical, dielectric, and catalytic properties. The influence of solid-state reactions, sol–gel, Pechini, hydrothermal, co-precipitation, microwave, and other mild chemical approaches on phase purity, morphology, particle size, and oxygen stoichiometry was examined. The structural diversity of perovskite and perovskite-like manganites, including simple ABO₃, double perovskites, multilayer, and low-dimensional systems, was characterized in relation to their functional properties. The review discussed the capabilities of methods for synthesizing and analyzing morphological properties, demonstrating the role of doping, cation substitution, oxygen vacancies, and Jahn–Teller distortions in controlling material properties. Prospects for the application of perovskite manganites in spintronics, magnetocaloric cooling, photocatalysis, gas-sensing devices, and energy conversion and storage systems were analyzed. This review highlights the structure–property–application relationship in perovskite manganites. Full article

Dietary fibers are valuable food components with documented health benefits, yet their native compact and highly crystalline structures often result in low water hydration, poor adsorption capacity, and limited bioactivity. Chemical modification offers a promising strategy to overcome these functional limitations by disrupting the dense structure and exposing active groups. This study aimed to investigate the effects of acid modification on the physicochemical properties of soybean and citrus dietary fibers and to evaluate the performance of the modified fibers in probiotic-fermented soy protein gels. Compared with native fibers, modified fibers exhibited reduced particle size, rougher and more porous microstructures, and increased exposure of hydroxyl groups. Consequently, they showed significantly (p < 0.05) enhanced hydration capacity (increased by 92–541%), antioxidant activity (increased by 15–65%), cholesterol adsorption (increased by 16–75%), and α-amylase inhibition (increased by 26–62%). When incorporated into soy protein-based gels, the modified fibers, particularly those from soybean, lowered gel pH, increased water holding capacity, gel strength, apparent viscosity, and storage modulus, while reducing strain, indicating improved gel network integrity. These findings indicate that acid modification effectively unlocks the functional potential of dietary fibers, positioning the modified fibers, especially from soybean, as promising prebiotic ingredients for plant-based fermented gel products. Full article

Silicon (Si) is a leading anode candidate for next-generation lithium-ion batteries owing to its high theoretical capacity (~4200 mAh/g), but its >300% volumetric expansion during lithiation causes particle pulverization, loss of electrical contact, and continuous solid electrolyte interphase (SEI) reformation, resulting in rapid capacity fade. Here, we report a single-walled carbon nanotube (SWNT)-templated porous Si/SiO₂ core–shell cylindrical hybrid anode synthesized by combining block copolymer-directed sol–gel assembly with controlled magnesiothermic reduction. SWNT bundles act as a three-dimensional structural template that directs the formation of a continuously interconnected cylindrical porous network, a geometry difficult to obtain by conventional particle-based compositing. The controlled, partial magnesiothermic reduction intentionally preserves residual amorphous SiO₂ within the porous shell as an electrochemically inactive mechanical buffer that suppresses Si volume expansion and stabilizes the electrode. A side-by-side comparison with a fully reduced, SiO₂-free counterpart of identical architecture isolates the role of the SiO₂ buffer in achieving long-term cycling stability. The SWNT-porous Si/SiO₂ hybrid delivers a reversible capacity of 1133 mAh/g in the first cycle and retains 90% of its initial capacity after 200 cycles at 1 C with 99.7% Coulombic efficiency, together with a rate capability of 482 mAh/g at 5 C. Post-cycling cross-sectional analysis confirms minimal electrode-level swelling (~2 μm) after 200 cycles, demonstrating the structural efficacy of the SWNT-templated porous architecture combined with the SiO₂ buffer for structurally stable Si anodes. Full article

Reservoir conformance control is a necessary production measure in the oil field, which significantly impacts the efficiency of enhanced oil recovery (EOR). Polymers, hydrophobic associating polymers (HAPs), polymer microgels (MGs), and preformed particle gel (PPG) are typical polymer/gel dispersion fluids that are widely used as conformance control agents. Currently, there is still no combined conformance control method to realize the equilibrium production of the reservoir. This paper first evaluates the reservoir adaptability of polymers, HAPs, and MGs by the three-parallel core displacement experiments. Then, the displacement equilibrium factor (DEF) was established by comprehensively considering the profile improvement, oil increment, and oil recovery to optimize the fluid switching time. Based on the above oil displacement experiments, a scatter plot of the DEF with respect to the ultimate recovery of each layer can be plotted, which has an inflection point when the DEF is 45%. When the DEF is lower than 45%, the difference in the oil displacement effect of each layer is enhanced. Therefore, the best time to switch the injection fluid is when the DEF is reduced to 45%. Finally, based on the above results, a graph guiding the combined conformance control method under different reservoir variation coefficients and reservoir median permeability was established, and an equilibrium production method for heterogeneous reservoirs was developed. The five-parallel core flooding experiments with the DEF < 45% as the switching guidance can increase the oil recovery by 17.79% based on association polymer flooding, which is 9.68% higher than that of the conventional conformance control method. This paper can provide theoretical and experimental support for the optimal design of conformance control in oilfields. Full article