Search Results (1,408)

Amorphous cobalt-phosphorous (CoP) coatings are a candidate to replace hard chromium and other traditional coatings. Here, electrodeposition of both amorphous and crystalline CoP coatings was performed at room temperature and in an air environment. The bath composition and deposition conditions were optimized to offer a low cost, low maintenance, and safe process. The effects of various deposition variables such as solution composition, pH, duration, and mixing parameters were studied, and the reproducibility of the process was demonstrated. Selected coatings were then thoroughly characterized by a variety of techniques. The best amorphous/nanocrystalline coating contained ca. 6.4 wt.% P after 1.2 h of deposition, and 7.2 wt.% P after 4 h of deposition. The best crystalline coating contained ca. 2.7 wt.% P after 1.2 h of deposition and between 2.3 and 5.5 wt.% P after 4 h of deposition. The amorphous coating had excellent mechanical properties: a high hardness (7.8 ± 0.7 GPa), high Young’s modulus (153 ± 9 GPa), and surprisingly low coefficient of dry friction (between 0.11 ± 0.02 and 0.17 ± 0.01). The coating could not be scraped from the substrate using a diamond scalpel blade. In a standard adhesion test, the sample failed neither cohesively within the coating nor adhesively between the coating and the substrate. In the as-deposited conditions, the structure was uniform, nanocrystalline, or had nanocrystals embedded in an amorphous matrix. The crystallization temperature of the amorphous alloy was 284 °C, and the phase transformation occurred only between 300 and 400 °C. The coatings developed and comprehensively characterized herein may be considered for aerospace, magnetic storage, fuel cells, water splitting, and other applications. Full article

In this study, whey protein isolate–soybean lecithin-encapsulated vitamin A emulsion (V_A-WSE) with different oil-to-water ratios was prepared and characterized. The impact of V_A-WSE on the physicochemical characteristics of Nemipterus virgatus surimi at varying concentrations was determined. The V_A-WSE emulsion exhibited the best stability when the oil-to-water (O:W) ratio was 1:1 (w/w). Composite gels prepared by mixing V_A-WSE (O:W = 1:1, w/w) with surimi at different ratios showed significantly improved gel properties. In particular, the hardness, chewiness, gel strength, and water-holding capacity of the composite gel with a V_A-WSE concentration of 8% (w/w) reached the highest values of 2629.00 g, 2051.27 g, 292.16 g·cm, and 87.10%, respectively. Similarly, the observed voids in the microstructural images gradually decreased with rising V_A-WSE concentration and were the smallest in the 8% sample group. Surimi gels showed remarkably enhanced hydrogen bonds in the V_A-WSE concentration range of 0–8%, increasing from 0.001 to 0.025 mg/mL (p < 0.05). Furthermore, it was observed that the energy storage modulus (G′) was larger than the loss modulus (G″), suggesting the dominant elastic characteristics of the composite gels. The solubility and total sulfhydryl group contents significantly increased from 30.33 to 88.29% and from 4.90 to 28.19 nmol/mg, respectively. In summary, V_A-WSE can promote the unfolding of the myofibrillar protein (MP) structure and improve the gel properties of surimi gels. These results support the development of functional surimi products. Full article

In order to explore the influence of storage temperature and time on the quality of vacuum-packed water caltrop shell (WCS), this study investigated the changes in the quality of vacuum-packed WCS under different storage temperature (3 ± 1 °C, 5 ± 1 °C and 7 ± 1 °C) and time. The quality-related parameters of WCS, including sensory quality, moisture content, texture characteristics and microstructure, were examined. The results showed that at the storage temperature of 5 ± 1 °C, vacuum-packaged WCS could maintain high sensory quality within 21 days, while at 3 ± 1 °C and 7 ± 1 °C, the samples showed low sensory quality at 21 days and 14 days, respectively. For the same storage time, storage at 5 ± 1 °C resulted in the least significant decrease in elastic modulus and compressive strength of the samples. Among the three storage temperatures, storage at 7 ± 1 °C led to the most obvious change in pore structure, followed by storage at 3 ± 1 °C and then 5 ± 1 °C. The variance analysis suggested that storage time has significant effects on all the tested parameters, while storage temperature has significant effects on the sensory quality and texture characteristics of the samples but shows no significant effect on the moisture content. These findings provide a theoretical reference for the packaging and storage of WCS and the development of water caltrop sheller. Full article

Dielectric characterization offers valuable insights into fruit structure, ripening, and storage stability. However, systematic studies on apples are still limited. This work elucidates the electrical and physicochemical properties of a specific variety of apples, Malus domestica, using Electrochemical Impedance Spectroscopy (EIS), a non-destructive, fast and cost-effective technique, suitable for real-time quality assessments. The apple samples were analyzed over the frequency range of 20 Hz–120 MHz at 25 °C, and impedance data were modeled using equivalent circuits and dielectric relaxation models. Physicochemical analyses confirmed a high moisture content (84%, wwb), pH 4.81, TSS 14.58 °Brix, and acidity 0.64%, which is typical of fresh Red Delicious apples. Impedance spectra revealed semicircular and Warburg elements in Nyquist plots, indicating resistive, capacitive, and diffusive processes. Equivalent circuit fitting with the proposed R-C-Warburg impedance model outperformed (R² = 0.9946 and RMSE = 6.610) the classical Cole and Double-Shell models. The complex permittivity (ε) represented a frequency-dependent ionic diffusion, space-charge polarization, and dipolar relaxation decay, while electrical modulus analysis highlighted polarization and charge carrier dynamics. The translational hopping of charge carriers was confirmed through AC conductivity following Jonscher’s power law with an exponent of ƞ = 0.627. These findings establish a comprehensive dielectric profile and advanced circuit fitting for biological tissues, highlighting a promising non-invasive approach using EIS for real-time monitoring of fruit quality, with direct applications in post-harvest storage, supply chain management, and non-destructive quality assurance in the food industry. Full article

This study examines how diabetes mellitus and physiological aging influence the nanomechanical behavior of rat rib cortical bone using combined static and dynamic nanoindentation. Ribs from young control, old, and streptozotocin-induced diabetic rats were analyzed to quantify both intrinsic and frequency-dependent mechanical properties. Static nanoindentation revealed markedly higher hardness and elastic modulus in the diabetic group (0.47 ± 0.22 GPa and 9.53 ± 3.03 GPa, respectively) compared to controls (0.11 ± 0.03 GPa and 3.21 ± 0.51 GPa; p < 0.001). The modulus-to-hardness ratio, an indicator of fracture toughness, was reduced from 30.34 in controls to 20.45 in diabetics, suggesting increased stiffness but greater brittleness. Dynamic nanoindentation (0–4.5 Hz) demonstrated significant aging-related changes in the storage and loss moduli (p < 0.001), while the loss factor (tan δ < 1) and viscosity remained similar across groups, indicating predominantly solid-like behavior. These results show that diabetes stiffens bone tissue through matrix-level alterations, whereas aging primarily affects its viscoelastic damping capacity. The combined static–dynamic nanoindentation protocol provides a robust framework for distinguishing disease- and age-related bone degradation at the tissue scale. Translationally, the findings help explain why bones in diabetic or elderly individuals may fracture despite normal mineral density, underscoring the need to assess bone quality beyond conventional densitometry. Full article

Shape memory polymer composites (SMPCs) are an intelligent class of materials capable of self-actuation, offering promising applications in diverse stimuli-responsive material systems. This study developed epoxy-based SMPCs reinforced with carbon–aramid fibers at a 15:85 ratio, with their glass transition temperature (T_g) tailored by incorporating 5 wt.% (SMPC-5) and 10 wt.% (SMPC-10) polyethylene glycol (PEG-600). Dynamic mechanical analysis (DMA) confirmed that PEG addition effectively reduced the T_g from 89.79 °C in the neat composite (SMPC-P) to 70.28 °C in SMPC-5 and 59.34 °C in SMPC-10. Incorporating 5 wt.% PEG enhanced storage and loss moduli, whereas excessive plasticization at 10 wt.% reduced stiffness. Infrared spectroscopy analysis revealed shifts and increased intensities in hydroxyl (OH), aliphatic C-H, and carbonyl (C=O) groups, indicating enhanced intermolecular interactions and bond formation. Tensile testing showed that the carbon–aramid filler significantly improved tensile strength and stiffness, with SMPC-10 achieving the highest tensile strength (233.59 MPa) and SMPC-5 the highest Young’s modulus (14.081 GPa). These results highlight the complementary role of carbon–aramid reinforcement and PEG plasticization in tuning thermomechanical behavior, providing baseline insights for designing SMPCs with tailored actuation and reliable structural performance. Full article

This study presents an enantiomeric-ratio-driven strategy for constructing mechanically robust supramolecular gels using cyclohexane bisurea derivatives. By employing non-equimolar enantiomeric mixtures, we achieved an ultralow critical gelation concentration (CGC < 2 mg/mL) in toluene, representing a reduction of more than fivefold compared to homochiral single-enantiomer systems. Rheological measurements revealed substantially enhanced mechanical properties in the non-equimolar gels, with yield stress and storage modulus values up to 17 and 20 times higher, respectively, than those of single-enantiomer gels. Morphological analyses (SEM and POM) indicated that pure enantiomers form isolated crystalline fibers with limited connectivity, whereas racemic mixtures yield disordered amorphous aggregates. In contrast, non-equimolar mixtures self-assemble into hierarchical “sea urchin-like” architectures, wherein crystalline fibers radiate from central cores to form densely interconnected networks. This unique structural motif underpins both the ultralow CGC and superior mechanical performance. Complementary FT-IR, XRD, and DSC analyses demonstrated that chiral imbalance modulates hydrogen-bonding interactions and structural order, while molecular dynamics (MD) simulations provided insight into the divergent self-assembly pathways among homochiral, racemic, and non-equimolar systems. This work provides a stereochemically guided approach for designing high-performance supramolecular gels with tailored hierarchical structures and enhanced functionality. Full article

This study aimed to minimize the amount of gelator used in oleogel preparation and enhance the valorization of rubber seeds. Cellulose extracted from rubber seed shells was modified via high-pressure microfluidization (HPM), which significantly enhanced its specific surface area from 0.92 m²/g (CL) to 6.47 m²/g (MCL), along with markedly improved water-holding capacity (WHC increased from 4.92 to 29.37 g/g) and swelling capacity (SC increased from 0.65 to 3.38 mL/g). The modified cellulose (MCL) served as the gelator, while rubber seed oil bodies (OBs), isolated through sucrose-assisted extraction, functioned as the oil phase. A series of OB emulsions containing 0% to 0.75% MCL were prepared and subsequently converted into oleogels by freeze-drying and shearing. Oleogels containing ≥0.45% MCL exhibited excellent oil binding capacity (OBC > 98.6%) and strong gel strength (storage modulus G′ > 10⁵ Pa). Texture profile analysis further confirmed significant improvements in the textural properties of the oleogels with increasing MCL content. These findings demonstrate that MCL, combined with rubber seed OBs, enables the development of high-performance oleogels with minimal gelator requirements. This approach not only reduces gelator usage but also provides a novel strategy for the upcycling of rubber seed shells, offering valuable insights for the design of nutrient-rich functional oleogels. Full article

The aim of this study is to evaluate the mechanical properties and long-term stability of 3D-printable resins for permanent fixed dental prostheses (FDPs), focusing on whether material performance is influenced by 3D-printer type or by differences in resin formulations. Specimens (N = 621) were printed. CAD/CAM blocks (BRILLIANT Crios) served as control. Flexural strength (FS) with elastic modulus (E_calc), Weibull modulus (m), Martens’ hardness (HM), indentation modulus (EIT), elastic modulus (E_RFDA), shear modulus (G_RFDA), and Poisson’s Ratio (ν) were measured initially, after water storage (24 h, 37 °C), and after thermocycling (5–55 °C, 10,000×). SEM analysis assessed microstructure. Data were analyzed using Kolmogorov–Smirnov, ANOVA with Scheffe post hoc, Kruskal–Wallis with Mann–Whitney U, and Weibull statistics with maximum likelihood (α = 0.05). A ceramic crown printed with Midas showed higher FS, HM, and EIT values after thermocycling than with Pro55s, and higher E_calc scores across all aging regimes. A Varseo Smile Crown Plus printed with VarseoXS and AsigaMax showed a higher FS value than TrixPrint2, while AsigaMax achieved the highest initial E_calc and E_RFDA values, and VarseoXS did so after thermocycling. HM, EIT, and G_RFDA were higher for TrixPrint2 and AsigaMax printed specimens, while ν varied by system and aging. 3Delta Crown, printed with AsigaMax, showed the highest FS, E_calc, HM, EIT, and m values after aging. VarseoSmile triniQ and Bridgetec showed the highest E_RFDA and G_RFDA values depending on aging, and Varseo Smile Crown Plus exhibited higher ν initially and post-aging. Printer system and resin formulation significantly influence the mechanical and aging behaviors of 3D-printed FDP materials, underscoring the importance of informed material and printer selection to ensure long-term clinical success. Full article

Yuanjiang Miscanthus lutarioriparius, which is rich in various bioactive components, exhibits significant potential in the development of functional foods. However, research on its application in dairy products remains relatively limited. This study fermented yogurt using different concentrations of Yuanjiang Miscanthus lutarioriparius water extract (0%, 0.1%, 0.2%, and 0.4%) as a functional additive, investigating its effects on the rheological properties, oxidative capacity, sensory quality, and volatile components of yogurt during storage. The results showed that during storage, the rheological properties (such as moisture content, apparent viscosity, storage modulus, etc.), the viable counts of Streptococcus thermophilus and Lactobacillus bulgaricus, and the DPPH/ABTS/FRAP radical scavenging rates of asparagus yogurt were significantly superior to those of the control group (p < 0.05), indicating that the lactic yogurt exhibited better texture, stability, and overall sensory acceptance. The 0.2% addition group exhibited the best inhibitory effect on lactic acid bacteria after acidification and the most stable acidity changes. The 0.4% addition group achieved an ABTS radical scavenging rate of 58.4% on the 7th day of storage, significantly higher than other groups (p < 0.05). The asparagus yogurt contained 64 volatile flavor compounds (20.31% alcohols and 21.88% ketones), which was higher than the control group (45 compounds), and introduced new aldehydes (tridecanal) and esters (methyl salicylate, ethyl palmitate), imparting a mild sourness and spicy flavor. Sensory evaluation results indicated that the 0.2% addition group scored the highest in texture, flavor, and taste, aligning with its rheological properties and color. This provides a theoretical basis for the development of highly stable and active functional asparagus yogurt. Full article

This study investigated the effects of homolactic fermentation on the rheological, viscoelastic, and starch structural properties of quinoa–chickpea flour-based beverages. Three formulations with increasing proportions of chickpea flour (10, 25, and 50%) were fermented for 10 h with Lactobacillus acidophilus LA-5. Apparent viscosity, deformation capacity, storage modulus (G′), and pasting behavior were measured along with FTIR-based analysis of the starch molecular structure. All fermented samples reached pH values < 4.5 and exhibited improved rheological properties with significant increases in viscosity and storage modulus (G′), particularly in the 50:50 blend. These enhancements were attributed to the synergistic effects of homolactic fermentation and inherent properties of chickpea starch, particularly its high amylose content, large granule size, and long amylopectin chains. FTIR analysis revealed that the short-range molecular order of starches was preserved after fermentation in all beverages, except for the 50:50 blend, as evidenced by the increased degree of order (DO) and double helix (DD) ratios. Overall, these findings demonstrate that integrating chickpea flour and controlled homolactic fermentation is an effective strategy for tailoring the viscosity and stability of plant-based probiotic beverages, providing a theoretical basis for the development of clean-label and functional fermented plant-based systems. Full article

The harsh conditions of the space environment necessitate advanced materials capable of withstanding extreme temperature fluctuations and ultraviolet (UV) radiation. While epoxy-based composites are widely utilized in aerospace due to their favorable strength-to-weight ratio, they are prone to degradation, especially under prolonged high-energy UV-C exposure. This study investigated the mechanical and chemical stability of epoxy composites reinforced with nanosilica at 0, 2, 5, and 10 wt% before and after UV-C irradiation. Dynamic mechanical analysis (DMA) revealed that increased nanosilica content enhanced the storage modulus below the glass transition temperature (Tg) but reduced both Tg and the damping factor. Following UV-C exposure, all samples showed a decrease in storage modulus and Tg; however, composites with higher nanosilica content maintained better property retention. Frequency sweeps corroborated these findings, indicating improved instantaneous modulus but accelerated relaxation with increased nanosilica. Fourier-transform infrared (FTIR) spectroscopy of UV-C-exposed samples demonstrated significant oxidation and carboxylic group formation in neat epoxy, contrasting with minimal spectral changes in nanosilica-modified composites, signifying improved chemical resistance. Overall, nanosilica incorporation substantially enhances the thermomechanical and oxidative stability of epoxy composites under simulated space conditions, highlighting their potential for more durable performance in low Earth orbit applications. Full article

Conductive polymer hydrogels have attracted extensive attention in wearable devices, soft machinery, and energy storage due to their excellent mechanical and conductive properties. However, their preparation is often complex, expensive, and time-consuming. Herein, we report a facile precipitation method to prepare conductive polymer composite hydrogels composed of poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), and poly(3,4-ethylenedioxythiophene) (PEDOT) via straightforward solution blending and centrifugation. During the preparation, PEDOT, grown along the PAA template, is uniformly dispersed in the hydrogel matrix. After shaping and rinsing, the PEDOT/PAA/PVA hydrogel shows good mechanical and electrical properties, with a conductivity of 4.065 S/m and a Young’s modulus of 311.6 kPa. As a strain sensor, it has a sensitivity of 1.86 within 0–100% strain and a response time of 400 ms. As a bioelectrode, it exhibits lower contact impedance than commercially available electrodes and showed no signs of skin irritation in the test. The method’s versatility is confirmed by the observation of similar performance of hydrogels with different compositions (e.g., polyaniline (PANI)/PAA/PVA). These results demonstrate the broad applicability of the method. Full article

This study introduces a single-step method to synthesize guar gum-based interpenetrating polymer network (IPN) hydrogels, achieving simultaneous Diels–Alder crosslinking and amoxicillin (AMOX) encapsulation under mild conditions. To evaluate the influence of porogen addition on IPN structure, drug loading and release, twenty-one formulations were developed, including AMOX loading (25% or 40% w/w relative to the polymer) and biocompatible porogens incorporation [polyethylene glycol (PEG) or sucrose at 5%, 10%, or 50% w/w]. All crosslinked IPN hydrogels formed robust gels, unlike non-crosslinked controls. Porogen choice strongly influenced hydrogel performance: PEG quadrupled the swelling index while enhancing storage modulus (up to 10,054 Pa) and complex viscosity (up to 1302 Pa·s), whereas high sucrose concentrations produced soft, ductile networks with critical strains above 20% and swelling indices up to 1895%. All hydrogels released AMOX at levels above MIC₅₀ for H. pylori. PEG-based IPN provided superior drug delivery profiles, with extended AMOX release (t₅₀ up to 15.5 h at pH 5.0), while sucrose-rich matrices exhibited faster burst release and disintegration. Single-step (pre-loading) AMOX during synthesis improved release control compared to post-loading. These findings highlight the potential of one-pot IPN synthesis with porogen modulation offering a promising gastroretentive platforms for sustained AMOX delivery against H. pylori. Full article

This study elucidates the mechanisms through which hydrocolloids inhibit oil penetration and improve the sensory quality of batter-coated fried fish cubes. Specifically, guar gum (GuG), linseed gum (LG), acacia senegal gum (AS), and gellan gum (GeG) were individually incorporated into the batter coating system at an addition level of 0.1%. The results indicated that the 0.1% LG-supplemented group significantly increased batter viscosity by 74.9% compared to the control, which in turn improved batter pickup by 26.1% and frying yield by 8.1%. Rheological analysis revealed that hydrocolloid-incorporated batters exhibited markedly higher storage modulus and loss modulus compared to the control group, with a lower loss tangent. Experimental results indicated that hydrocolloids effectively reduced oil absorption and mitigated the rate of lipid oxidation in fried fish cubes while promoting the release of key flavor compounds. Notably, fried fish cubes coated with GuG, when fried at 170 °C, not only reduced oil absorption but also facilitated the formation of critical flavor compounds. These findings provide a theoretical foundation for optimizing fried food processing and flavor control. Full article