Search Results (532)

Background: Local anesthesia is essential for most dental procedures, but its parenteral administration is often painful. Topical anesthetics are commonly used to minimize local anesthesia pain; however, commercial formulations fail to fully prevent the discomfort of local anesthetic injection. Methods: We developed and characterized a novel lidocaine and epinephrine co-loaded liquid crystalline precursor system (LCPS) for topical anesthesia. The formulation was structurally characterized using polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). Rheological behavior was assessed through continuous and oscillatory rheological analyses. Texture profile analysis, in vitro mucoadhesive force evaluation, in vitro drug release and permeation studies, and an in vivo toxicity assay using the chicken chorioallantoic membrane (CAM) model were also conducted. Results: PLM and SAXS confirmed the transition of the LCPS from a microemulsion to a lamellar liquid crystalline structure upon contact with artificial saliva. This transition enhanced formulation consistency by over 100 times and tripled mucoadhesion strength. The LCPS also provided controlled drug release, reducing permeation flow by 93% compared to the commercial formulation. Importantly, the CAM assay indicated that the LCPS exhibited similar toxicity to the commercial product. Conclusions: The developed LCPS demonstrated promising physicochemical and biological properties for topical anesthesia, including enhanced mucoadhesion, controlled drug delivery, and acceptable biocompatibility. These findings support its potential for in vivo application and future clinical use to reduce pain during dental anesthesia procedures. Full article

The cosmetic industry is growing at an impressive rate worldwide. In the cosmetic field, natural-origin ingredients represent the new frontier in this industry. Among the main components of cosmetics, lipids, emulsifiers, rheological modifiers, preservatives, colorants, and antioxidants can be found. These compounds form emulsions, which are among the main cosmetic formulations. An important aspect in this regard is the evaluation of emulsions’ stability over time and emulsions’ production methodology. In this paper, a comparison is made between two emulsion production technologies, the Standard and the “One-Pot” methods, through the characterization of the raw material ABWAX^® Revomul, a multifunctional wax for cosmetic use which consists of a low-melting structuring wax of vegetal origin (Rhus wax) and a natural emulsifier (Polyglyceril-3 Stearate). First, we evaluated the affinity between the wax raw materials and emollients of different chemical nature; then, we analyzed the impact of the production method on the emulsions to identify similarities and differences. ABWAX^® Revomul demonstrated a high level of effectiveness in regard to stabilizing water-in-oil emulsions. This study suggests that from an industrial point of view, the application of the two procedures allows products with different characteristics to be obtained, consequently allowing a specific method to be chosen to obtain the desired product. Full article

Magnetorheological fluids (MRFs) and elastomers (MREs) are two types of smart materials that exhibit modifiable rheological properties in response to an applied magnetic field. Although they share a similarity in their magnetorheological response, these two materials differ in their nature, structure, and mechanical behavior when exposed to a magnetic field. They also have distinct application differences due to their specific rheological properties. These fundamental differences therefore influence their properties and applications in various industrial fields. This review provides a synthesis of the distinct characteristics of MRFs and MREs. The differences in their composition, rheological behavior, mechanical properties, and respective applications are summarized and highlighted. This analysis will enable a comprehensive understanding of these differences, thereby allowing for the appropriate selection of the material based on the specific requirements of a given application and fostering the development of new applications utilizing these MR materials. Full article

In response to the growing demand for improving the nutritional profile of widely consumed products, such as cookies, there has been an increasing interest in fat replacers that preserve sensory attributes and have a more positive health effect. Among the novel fat replacement strategies, the incorporation of bigels into food formulations has been studied; however, the impact of Arabic gum hydrogel-based bigels on microstructural properties and their correlation with the texture and quality of bakery products remains underexplored. In this study, cookies were formulated using a plant-based bigel (canola oil-carnauba wax oleogel mixed with Arabic gum hydrogel) as a fat substitute, and their microstructural, textural, and quality parameters were compared with those of commercial butter-based cookies. Compared to butter (firmness of 29,102 g, spreadability of 59,624 g∙s, and adhesiveness of 2282 g), bigel exhibited a softer (firmness of 576 g), more spreadable (spreadability of 457 g∙s), and less adhesive texture (adhesiveness of 136 g), while its rheological properties showed similar behavior but at a lower magnitude. Bigel exhibited high thermal stability and good elastic and thixotropic behaviors, indicating reversible structural breakdown and recovery. Cookies prepared with bigels instead of butter exhibited a similar proximate composition, with a slight increase in lipid content (11.7%). The physical dimensions and density were similar across the formulations. However, the microstructural analysis revealed differences when bigels were incorporated into cookies, reducing porosity (55%) and increasing the mean pore size (1781 µm); in contrast, mean wall thickness remained unaffected. Despite these structural modifications, the potential of bigels as viable and nutritionally enhanced substitutes for conventional fats in bakery products was demonstrated. Full article

The physical and rheological properties of mucilage hydrogels derived from the cladodes of Opuntia ficus-indica (L. Mill) were compared with those of commercial pectin for potential applications in the food industry. All hydrogels—formulated by incorporating sucrose and either calcium chloride or calcium carbonate to promote favorable gel network formation—exhibited pseudoplastic (shear-thinning) behavior. The flow characteristics of the hydrogels prepared with mucilage or pectin conformed to the Casson fluid model. Moreover, all samples consistently displayed loss modulus (G″) values exceeding their corresponding storage modulus (G′) values, indicating a dominant viscous behavior over elastic properties. The ζ-potential of all samples was negative across the pH range studied. Mucilage-based samples exhibited lower ionizability per unit mass and reduced phase stability compared to those containing pectin. Principal component analysis (PCA) revealed that mucilage hydrogels exhibited multivariate profiles similar to pectin hydrogels containing calcium carbonate, though the latter demonstrated greater polydispersity than standard pectic gels. Infrared spectroscopy further highlighted distinct spectral differences between pectins and mucilages, offering valuable insights into their respective functional characteristics. Collectively, these findings underscore the potential of Opuntia ficus-indica mucilages as viable additives in food formulations. Full article

This study investigates cement–bentonite slurries with hydration accelerators for borehole backfilling applications in infrastructure reconstruction projects. Two formulations with different accelerator dosages (5 and 10 kg/m³) were evaluated through combined experimental testing and Moving Particle Semi-implicit (MPS) numerical modeling to optimize material performance. The research focuses on time-dependent rheological evolution and its impact on construction performance, particularly bleeding resistance and workability retention. Experimental flow tests revealed that both formulations maintained similar initial flowability (240–245 mm spread diameter), but the higher accelerator dosage resulted in 33% flow reduction after 60 min compared to 12% for the lower dosage. Bleeding tests demonstrated significant improvement in phase stability, with bleeding rates reduced from 2.5% to 1.5% when accelerator content was doubled. The MPS framework successfully reproduced experimental behavior with prediction accuracies within 3%, enabling quantitative analysis of time-dependent rheological parameters through inverse analysis. The study revealed that yield stress evolution governs both flow characteristics and bleeding resistance, with increases several hundred percent over 60 min while plastic viscosity remained relatively constant. Critically, simulations incorporating time-dependent viscosity changes accurately predicted bleeding behavior, while constant-viscosity models overestimated bleeding rates by 60–130%. The higher accelerator formulation (10 kg/m³) provided an optimal balance between initial workability and long-term stability for typical borehole backfilling operations. This integrated experimental–numerical approach provides practical insights for material optimization in infrastructure reconstruction projects, particularly relevant for aging infrastructure requiring proper foundation treatment. The methodology offers construction practitioners a robust framework for material selection and performance prediction in borehole backfilling applications, contributing to improved construction quality and reduced project risks. Full article

Alternative energies have become relevant in global strategies to address climate change, and third-generation biodiesel derived from the generation of lipids from microalgae represents a viable option. This process can also be coupled with wastewater treatment to remove organic matter. To determine the effects of two catalyst levels (1 and 1.5% KOH) and two molar ratios of alcohol (methanol) with oil (1:6 and 1:9) on the conversion of lipids into FAMEs and the quality of the biodiesel produced, this work suggests a method for the ultrasonication-based extraction of lipids from C. vulgaris. It also employs an experimental 2² design and three replicates. It was found that with a molar ratio of 1:9 and a 1% catalyst, the highest yield of 98.48 ± 1.13% was achieved. The FAME profile was similar to the profiles obtained in cultures with bold basal medium or INETI. The quality of the biodiesel met ASTM standards, achieving refractive indices of 1.435–1.478. The flash point (FP) was 165 ± 18 °C, and the acid number was 0.31 ± 0.17 mg KOH/g. The viscosity ranged from 4.33 to 4.87 mm²/s. However, the rheological behavior was correlated with the Ostwald–de Waele model with pseudoplastic behavior. Full article

This study investigates the mechanical properties of double hydrophilic block copolymers (DHBCs) based on poly[oligo(ethylene glycol) methacrylate] (POEGMA) and poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC) blocks by employing small amplitude oscillatory shear (SAOS) rheological measurements. We report that the mechanical properties of DHBCs are governed by the interfacial glass transition temperature (T_g^inter), verifying the disordered state of these copolymers. An increase in zero shear viscosity can be observed by increasing the VBTMAC content, yielding a transition from liquid-like to gel-like and finally to an elastic-like response for the PVBTMAC homopolymer. By changing the block arrangement along the backbone from statistical to sequential, a distinct change in the viscoelastic response is obvious, indicating the presence/absence of bulk-like regions. The tunable viscosity values and shear-thinning behavior achieved through alteration of the copolymer composition and block arrangement along the backbone render the studied DHBCs promising candidates for drug delivery applications. In the second part, the rheological data are analyzed within the framework of the classical free volume theories of glass formation. Specifically, the copolymers exhibit reduced fractional free volume and similar fragility values compared to the PVBTMAC homopolymer. On the contrary, the activation energy increases by increasing the VBTMAC content, reflecting the required higher energy for the relaxation of the glassy VBTMAC segments. Overall, this study provides information about the viscoelastic properties of DHBCs with densely grafted macromolecular architecture and shows how the mechanical and dynamical properties can be tailored for different drug delivery applications by simply altering the ratio between the two homopolymers. Full article

In recent years, there has been a surge in the extrusion-based 3D printing of materials for various biomedical applications. This work presents a novel methodology for optimizing extrusion-based 3D bioprinting of a gelatin/siloxane hybrid material for biomedical applications. A systematic approach integrating rheological characterization, computational fluid dynamics simulation (CFD), and machine-learning-based image analysis, was employed. Rheological tests revealed a shear stress of 50 Pa, a maximum viscosity of 3 × 10⁵ Pa·s, a minimum viscosity of 0.089 Pa·s, and a shear rate of 15 rad/s (27G nozzle, 180 kPa pressure, 32 °C temperature, 30 mm/s velocity) for a BIO X bioprinter. While these parameters yielded constructs with 54.5% similarity to the CAD design, a multi-faceted optimization strategy was implemented to enhance fidelity, computational fluid dynamics simulations in SolidWorks, coupled with a custom-develop a binary classifier convolutional neuronal network for post-printing image analysis, facilitated targeted parameter refinement. Subsequent printing optimized parameters (25G nozzle, 170 kPa, 32 °C, 20 mm/s) achieved a significantly improved similarity of 92.35% CAD, demonstrating efficacy. The synergistic combination of simulation and machine learning ultimately enabled the fabrication of complex 3D constructs with a high fidelity of 94.13% CAD similarity, demonstrating the efficacy and potential of this integrated approach for advanced biofabrication. Full article

This study investigates the consistent and uniform movement of two spherical particles within an infinite porous medium saturated with a couple stress fluid, with a particular focus on the effects of surface slippage. The research reveals that surface slippage significantly reduces the drag force experienced by the particles, thereby influencing their hydrodynamic interactions. Conversely, increases in permeability and particle size similarity tend to enhance both the drag force and the inter-particle interaction forces, affecting the overall dynamics of particle motion. The analysis is conducted within the low-Reynolds-number regime, characteristic of laminar flow dominated by viscous forces, and employs boundary collocation methodologies to derive semi-analytical solutions to the governing differential equations. This approach enables a detailed characterization of the flow behavior and inter-particle forces in intricate fluid environments, including those with porous matrices and complex rheological properties. The findings from this investigation are consistent with prior numerical analyses, notably those conducted by Alotaibi and El-Sapa (2025), and corroborate earlier studies by Shehadeh and Ashmawy (2019), which examined cases of no slippage and permeability effects. Additionally, the results align with earlier research by Shreen et al. (2018) concerning viscous fluids, thereby reinforcing the validity of the conclusions. Overall, the study enhances the understanding of particle-fluid interactions in porous, couple stress-rich media, providing valuable insights into the roles of surface slippage, permeability, and particle size in determining hydrodynamic forces. Full article

Background/Objectives: The similarities and differences from a rheological perspective between significant short focal and mild long coronary lesions warrant investigation to elucidate wall shear stress (WSS) angiographic discrepancies. Methods: Patients who underwent coronary computed tomography angiography (CCTA) between 1 January 2023 and 1 September 2024 were selected for computational fluid dynamics (CFD) analysis. The selection criteria included either a focal (≤20 mm) hemodynamically significant stenosis, defined as ≥75% lumen narrowing, or a long (30–40 mm) non-hemodynamically significant lesion showing ≤50% stenosis of the left anterior descending (LAD) artery. Patient-specific models were reconstructed from ECG-gated CCTA images. Wall shear stress (WSS, measured in Pascals) and residence time (RT) were evaluated for each patient. Results: The LAD arteries of 30 patients (mean age 54 years, 63.3% men) were evaluated: 16 with focal, hemodynamically significant coronary stenosis, while 14 with diffuse, long, non-hemodynamically significant coronary lesions. Both groups exhibited a lower mean WSS compared to the non-stenosed segment, with no significant difference in mean WSS between the two groups (p = 0.84). Conversely, both groups demonstrated a higher mean residence time (RT) compared to the non-stenosed segments (0.2 ± 0.06 vs. 0.60 ± 0.03, p < 0.001 and 0.2 ± 0.006 vs. 0.59 ± 0.02, p < 0.001, respectively), and no significant difference in mean RT (p = 0.82). Conclusions: Long, angiographically mild coronary stenoses show similar WSS and RT characteristics compared to short hemodynamically significant coronary stenosis. Full article

Fats play a key role in the rheological and textural properties of meat products. However, growing awareness of the link between diet and disease has stimulated research on fat replacers that can replicate these functional properties. Inulin, a β-D-fructose polymer available in various degrees of polymerization (DP), is promising as a fat replacer due to its gel-forming ability in aqueous systems and its neutral sensory profile. This study focused on optimizing the formulation of inulin gel-based fat replacers for producing reduced-fat beef burgers. A D-optimal mixture-process design was employed, considering inulin with high-DP (HDP) and low-DP (LDP). The aim was to determine the optimal amount of inulin, water, and guar gum to achieve gels with rheological properties (η, shear viscosity; K, consistency index) similar to beef fat. The optimal formulations consisted of 51.52% inulin, 48.48% water, 1.50% guar gum for LDP gel, and 39.12% inulin, 60.88% water, 1.50% guar gum for HDP gel. These gels demonstrated shear viscosity and consistency indices comparable to beef fat. While rheological behavior at constant temperatures was similar, inulin gels showed increasing viscoelastic moduli (G′ and G″) with temperature, in contrast to the melting behavior of animal fat. When used in beef burger formulations, the optimized gels resulted in improved cooking yields, reduced shrinkage, and better dimensional stability compared to conventional controls. These benefits are attributed to the hydrophilic and stabilizing properties of inulin. The findings support the use of inulin-based gels as effective fat replacers, offering a promising strategy to reduce fat content in meat products without compromising functional quality. Full article

To improve the recycling content of Reclaimed Asphalt Pavement (RAP), this paper utilizes the characteristic of aged and hardened asphalt in RAP materials by adopting the High-modulus Asphalt Mixture design method for high-RAP-content recycling. First, the basic technical performance, fatigue properties, rheological characteristics, and chemical functional groups of reclaimed asphalt, 30# hard asphalt, and Styrene-Butadiene-Styrene (SBS)-modified asphalt were analyzed. The results revealed significant similarities in various metrics between reclaimed and hard asphalt, demonstrating the feasibility of replacing hard asphalt with reclaimed asphalt in a High-modulus Asphalt Mixture design. Next, High-modulus Asphalt Mixtures, EME13, with different RAP contents (0%, 20%, 40%, 60%) were designed and compared with SBS-modified Sup13 mixtures. The results indicated that (1) as the RAP content increased, the high-temperature performance of EME13 improved by 20~60%, while its low-temperature and intermediate-temperature crack resistance slightly declined by 10~20%. The dynamic modulus in the low-frequency region increased by 3~6 times, whereas the high-frequency dynamic modulus decreased by 20~30%. RAP enabled EME13 to meet the modulus design requirements more readily for High-modulus Asphalt Mixtures. (2) Although the SBS-modified Sup13 exhibited superior pavement performance compared to EME13, its cost was significantly higher. EME13 with high RAP content demonstrated notable economic advantages despite slightly lower pavement performance than Sup13. This research provides a new technical approach for the high-content recycling of RAP materials. Full article

The influence of biopolymer–biopolymer chain interactions on selected rheological properties of aqueous solutions from konjac (KG), xanthan gum (XG), and carboxymethyl cellulose (CMC) was investigated using viscosity measurements in extensional and shear flow, as well as normal force ($F_N$) measurements generated in shear flow. It was found that a KG solution of 0.05% behaves as a Newtonian fluid. Other solutions of KG (0.1, 0.2%), XG, and CMC revealed a non-linear dependence of viscosity on the shear rate. The extensional viscosity dependence on the elongation rate was non-linear and indicated shear-thinning over the entire KG concentration range, with the lowest values noted at 0.05% (0.5–0.8 Pas) and the highest at 0.2% (1.0–1.3 Pas). Similar observations were obtained with 0.1% XG and CMC solutions. Analysis regarding the shear rate dependence of the $F_N$ showed that hysteresis was observed for all KG concentrations tested. Only for the 0.2% KG solution were the $F_N$ values negative over the entire range of shear rates estimated, as in the case of the XG and CMC solutions. The obtained time constants from the DeKee model indicate the dominance of elastic contributions for the XG and CMC solutions and viscous contributions for the CMC solutions in the case of an extensional flow. Full article

As health concerns and regulatory pressures over saturated and trans fats grow, there is a growing need for healthier alternatives to traditional solid fats, such as butter and hydrogenated oils, that are still widely used in the food system. In this study, cellulose particle-based Pickering emulsions (CP-PEs) were prepared from microcrystalline cellulose and ethylcellulose and then foamed to obtain edible oleofoams (CP-EOs) as a solid-fat replacer. The average size of CP-PE droplets without surfactant was 598 ± 69 nm, as confirmed by confocal and transmission electron microscopy. Foaming with citric acid/NaHCO₃ and structuring with ≥6% glyceryl monostearate resulted in CP-EOs with an overrun of 147 ± 4% and volumetric stability for 72 h. Micro-computed tomography showed a uniform microcellular network, while the rheological analysis showed solid-like behavior with a storage modulus higher than butter. Differential scanning calorimetry showed a melting enthalpy similar to unsalted butter (10.1 ± 0.9 J/g). These physicochemical properties demonstrate that CP-EOs can closely mimic the firmness, thermal profile, and mouth-feel of conventional solid fats and may provide a promising solid-fat replacer. Full article