Search Results (294)

Background/Objectives: Ursodeoxycholic acid (UDCA) is a bile acid widely used for the treatment of cholestatic liver diseases; however, its poor aqueous solubility represents a major limitation for the development of oral liquid formulations, particularly in pediatric patients requiring accurate and flexible dosing. This study aimed to develop and characterize a fully solubilized extemporaneous UDCA oral formulation using the ready-to-use vehicle Wagner, with particular emphasis on the role of hydroxypropyl-β-cyclodextrin (HP-β-CD) as a solubilizing excipient. Methods: Phase-solubility studies, Job’s plot analysis, and ¹H NMR spectroscopy were performed to investigate the host–guest interaction between UDCA and HP-β-CD, confirming the formation of a stable 1:1 inclusion complex responsible for a marked increase in drug solubility. The aqueous solubility of UDCA increased from approximately 0.02 mg/mL in water to 31 ± 1 mg/mL in the Wagner base containing HP-β-CD, compared to ~10 mg/mL in the corresponding cyclodextrin-free vehicle. Chemical stability was evaluated using an HPLC method adapted from the European Pharmacopoeia, employing dual detection (refractive index and photodiode array detector) to ensure specificity and stability-indicating capability. Results: The UDCA solution (20 mg/mL) remained chemically stable for at least 4 months under refrigerated (4–8 °C) and room temperature (25 °C) conditions, with only moderate degradation observed at 40 °C. Physical stability studies confirmed the absence of precipitation, phase separation, or significant pH variations under all storage conditions. Conclusions: Wagner-based formulation enabled the development of a stable and homogeneous UDCA oral solution, providing a complementary formulation strategy to conventional suspension-based preparations. This approach represents a robust and patient-oriented strategy for extemporaneous compounding, particularly suitable for pediatric use. Full article

The Shuttleworth and Lippman equations are well-known equations used to link surface tension and stress (Shuttleworth) and surface tension and electric surface potentials (Lippmann). We show that the Shuttleworth and Lippman equations have a common thermodynamic basis, common to systems that possess a relatively large interfacial energy. This is relevant for problems of droplet stability, colloidal suspensions, electrode surfaces and more. Both equations are derived for systems that are not Euler homogeneous in the manner classical systems are. Hill’s thermodynamics for small systems is used to address this problem. Small in this context refers to systems with interfacial energies that are size- or shape-dependent. The resulting Hill–Gibbs–Duhem equation, an extension of the classical Gibbs–Duhem’s equation, gives the common basis for the Shuttleworth and Lippman equations. Hill’s thermodynamics enables us to rigorously define two types of surface tension, the differential surface tension and the integral surface tension. These surface tensions are linked by the system’s subdivision potential. From Helfrich’s equation we obtain a scaling law for the subdivision potential as function of the interfacial curvature. The dependence of the resulting subdivision potential on the system curvature is predicted. A critical analysis of the literature about the Shuttleworth and Lippman equations is given. Full article

Beauveria bassiana is one of the most widely used entomopathogenic fungi in insect pest management, and the need for rapid and reproducible quantification of fungal conidia to monitor process performance and to quality control products during biopesticide production is imperative. Conventional methodologies, such as hemocytometer counting and plate dilution assays, are time consuming, laborious and subject to significant operator-to-operator variability. Although optical methods have been increasingly explored for estimating fungal propagule concentrations, species-specific calibration, suspension stability, wavelength selection, and independent validation remain important for routine applications. In this study, we developed an agar–water-assisted UV–visible spectrophotometric calibration protocol for estimating conidial concentration using B. bassiana as a model entomopathogenic fungus. A 0.1% (w/v) agar–water suspension was used in order to get homogeneous, stable dispersions of conidia for optical measurements. Calibration of conidia concentration was accomplished through reliable optical density (OD) values measured at wavelengths 500 nm, 530 nm, 560 nm, 600 nm, and 650 nm. Linear correlations were observed across the tested wavelengths, with the highest goodness of fit for the model at 650 nm (R² = 0.9907). The resulting regression equation, conidia concentration (×10⁷ mL⁻¹) = 4.184 × OD₆₅₀—0.12450, has been independently verified with separate conidia batches, resulting in acceptable relative errors ranging from 13.78% and 18.98%. This agar–water-assisted OD₆₅₀ calibration model provides a practical and species-specific tool for the standardization of conidial dosages in biopesticide research, facilitating the reliable evaluation and application of entomopathogenic fungi within integrated pest management systems. Full article

Background/Objectives: Vernal keratoconjunctivitis (VKC) is a chronic, recurrent allergic disease with the risk of permanent injury or visual disabilities. Tacrolimus (FK506) is a potent immunosuppressant with insoluble ability and a high molecular weight. Methods: To address this disease, we successfully prepared FK506-loaded polymeric micelles (0.01%, FK506-MS) by a simple, organic solvent-free method. The physicochemical properties of FK506-MS were characterized. Corneal permeability, biocompatibility, and bioavailability were evaluated in vitro and in vivo in comparison with a commercially available FK506 suspension (0.1%, FK506-Susp). Therapeutic efficacy was also assessed in a murine model of VKC. Results: FK506-MS exhibited a small, homogeneous particle size with near-neutral surface charge. FK506-MS displayed a rapid and sustained release, along with excellent biocompatibility and stability. Ocular pharmacokinetic studies in rabbits revealed that FK506-MS, despite being only one-tenth the concentration of FK506-Susp, could achieve sufficient concentration in the conjunctiva with a prolonged half-life (T1/2) while systemic exposure in blood was markedly reduced. FK506-MS elicited comparable therapeutic responses across evaluated parameters: clinical symptoms, molecular biomarkers of inflammation, and histopathological findings. Conclusions: The dose-sparing advantage of FK506-MS suggests that the conventional paradigm of concentration-dependent therapeutic efficacy may require further refinement. The nanomicellar delivery system not only overcomes the solubility limitation of FK506 but also exhibits a potential therapeutic paradigm: achieving comparable clinical efficacy with a lower dose and reduced systemic exposure. These results provide a promising preclinical basis for the potential development of a topical tacrolimus therapy that may offer improved safety, cost-effectiveness, and patient adherence. Full article

This study describes the development of an electrochemical sensor for quantitatively measuring acetaminophen (ACOP) in drug tablets. The sensor design is based on the modification of glassy carbon electrode (GCE) using zinc oxide nanoparticles (ZnONPs) embedded in a naturally occurring clay matrix (Sa) functionalized with phenylalanine (Phe). To ensure that the ZnONPs are homogeneously dispersed on the clay surface, the nanocomposite was synthesized using an impregnation approach and low-temperature heat treatment. The amino acid promotes specific interactions with ACOP through hydrogen bonding and π-π stacking, acting as both a stabilizing agent and a molecular recognition moiety. FTIR, UV-Vis, XRD, and FESEM/EDX mapping were employed to fully characterize the developed material (ZnONPs-Sa/Phe). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used for the electrochemical determination of ACOP using the modified electrode GCE/ZnONPs-Sa/Phe. Parameters susceptible to affecting the sensitivity of the developed sensor were optimized, revealing that 5 µL of the suspension ZnONPs-Sa/Phe immobilized on GCE was ideal for the sensing of ACOP in a phosphate buffer solution at pH 2.0. The calibration curve obtained by plotting peak current intensity against ACOP concentration exhibited linear behavior within the concentration range between 0.02 µM and 0.28 µM, enabling determination of the limits of detection (LOD) and quantitation (LOQ) at 8.54 × 10⁻⁹ M and 2.84 × 10⁻⁸ M, respectively. The reproducibility, stability, and selectivity of the sensor were evaluated, followed by its application to the nano-sensing of ACOP in Africure and Doliprane tablets, yielding satisfactory results. The simplicity, affordability, and high analytical sensitivity of the developed sensor make this sensing platform a promising tool for pharmaceutical quality control applications. Full article

This work presents a comparative study of micro- and nano-scale fillers in liquid composite molding processes, focusing on how particle size and morphology affect resin rheology, flow behavior, and filler filtration within fiber preforms. Glass microspheres and organo-modified montmorillonite were dispersed in epoxy resin and injected through glass-mat preforms at different fiber volume fractions (ranging from 0.27 to 0.47). Our study integrates rheological characterization, in situ flow-front tracking, unsaturated permeability analysis, thermogravimetric quantification of retained particles, and microstructural observations by SEM. Despite their smaller loading, nanoclay suspensions showed a markedly higher viscosity increase than microsphere systems, yet their permeability remained nearly unchanged. In contrast, microsphere-filled resins exhibited strong filtration at the flow inlet, density-driven settling near the lower tool face, and significant permeability loss. The results demonstrate that nano-fillers, although more viscous, maintain homogeneous distribution and flow continuity, whereas micro-fillers promote cake formation and local compaction. This controlled side-by-side comparison clarifies how filler size and shape govern filtration mechanisms in liquid composite molding (LCM), providing design guidelines for processing filled resin systems without compromising part quality. Full article

High-intensity conditioning (HIC) is a common pretreatment process for enhancing the flotation of fine-grained minerals. This study introduces fractal theory into the structural design of pulp conditioning impellers. A fractal blade with multi-scale fractal edge features was proposed, and its separation performance was evaluated in a fine-grained malachite (−20 μm) and quartz flotation system. Computational fluid dynamics simulation revealed that the fractal blade altered the energy dissipation pattern. Compared with conventional rectangular blades, it induced stronger fluid compression and collision effects in localized regions. These hydrodynamic changes improved the suspension homogeneity and dispersion efficiency of fine-grained malachite. Furthermore, the fractal blade reduced the scale of turbulent vortices while increasing local turbulent kinetic energy and shear rates. This optimized turbulent flow field effectively reduced mass-transfer resistance and promoted interfacial interactions between flotation reagents and mineral particles. Adsorption experiments and optical microscopy indicated that after conditioning at 1500 rpm for 3 min, the fractal blade increased sodium oleate adsorption on malachite compared to the conventional blade. This enhanced adsorption promoted the aggregation of fine-grained malachite, increasing its aggregate size by 15.52%, while no significant aggregation was observed for quartz particles. Consequently, the single mineral flotation recovery of fine-grained malachite increased by 4.13%. For artificial mixed minerals, the copper concentrate grade and recovery were improved by 2.28% and 1.04%, respectively. This study provides a theoretical basis for equipment optimization and structural innovation design in HIC processes. Full article

This study investigates the effect of a 30 wt.% solid-content colloidal nano-silica (CNS) suspension, incorporated at 0–6 wt.% of cement, on the early-age (7 and 14 days) and later-age (28 and 56 days) compressive strength and microstructure of pumice aggregate lightweight concrete (PALC). The corresponding effective solid nano-silica content ranges from 0 to 1.8 wt.% of cement. Compressive strength increased with CNS dosage up to 5 wt.%, after which a plateau behavior was observed. At 7 days, compressive strength increased from 19.93 MPa to 26.81 MPa, corresponding to an improvement of approximately 34.5%. Although the 6 wt.% mixture showed slightly higher strength at early age, this trend was not sustained at later ages. The highest compressive strength at 56 days was obtained at 5 wt.% CNS (39.68 MPa), with a slight decrease at 6 wt.% CNS. X-ray diffraction (XRD) analysis indicated a reduction in calcium hydroxide (CH) peak intensity with increasing CNS content, suggesting the occurrence of pozzolanic reactions; however, this interpretation remains qualitative. Scanning electron microscopy (SEM) observations revealed a denser and more homogeneous matrix structure at 5 wt.% CNS, corresponding to improved mechanical performance. Slump values decreased from 9.0 cm to 6.6 cm with increasing CNS dosage, indicating reduced workability, while water absorption values slightly decreased from 18.51% to 17.20%. Full article

This study presents a comprehensive comparative analysis of the performance, combustion, and emission characteristics of a single-cylinder, four-stroke spark-ignition engine fueled by commercial gasoline and raw biogas enhanced with cerium oxide (CeO₂) nanoparticles. Raw biogas containing 58% methane was tested without carbon dioxide removal to reflect practical rural applications, while CeO₂ nanoparticles were ultrasonically dispersed in the fuel to promote homogeneous suspension and catalytic activity. Experiments were conducted under wide-open and part-throttle conditions across a range of engine speeds, with simultaneous measurement of brake thermal efficiency, brake-specific fuel consumption, volumetric efficiency, in-cylinder pressure, heat release rate, combustion phasing, and regulated emissions. The results showed that while gasoline consistently outperformed biogas in torque and power due to its higher heating value and flame speed, the addition of CeO₂ significantly reduced the performance gap. For the biogas mode, CeO₂ addition increased brake thermal efficiency by up to 5%, lowered brake-specific fuel consumption by up to 8%, and shifted the start of main combustion to earlier crank angles, indicating faster and more complete combustion, particularly at high loads where higher temperatures activate CeO₂’s catalytic behavior. Emission analysis revealed that CeO₂-blended biogas reduced carbon monoxide emissions by approximately 25% and unburned hydrocarbons by up to 55% compared with gasoline, while nitrogen oxide emissions were consistently 15–22% lower. These reductions were observed across both wide-open and part-throttle conditions, confirming improved combustion completeness and lower peak flame temperatures. These improvements are attributed to CeO₂’s oxygen-storage capability, catalytic oxidation activity, and enhanced thermal conductivity, which collectively strengthen combustion completeness and cyclic stability. The findings demonstrate that nanoparticle-enhanced biogas can substantially improve the environmental and operational viability of spark-ignition engines, offering a practical pathway for integrating renewable gaseous fuels into existing transportation systems. Full article

Biological soil crusts (BSCs) are critical ecological components in arid lands. Their formation and stability hinge on the assembly and interactive networks of cyanobacteria-led bacterial communities. Yet, how different functional cyanobacteria shape the underlying microbial structure and assembly rules is poorly understood. Here, we cultivated artificial algal crusts using two representative cyanobacteria: the nitrogen-fixing Leptolyngbya sp. and the non-nitrogen-fixing Microcoleus vaginatus (M. vaginatus CM01). A total of six treatments were established based on the presence or absence of spraying with in situ BSCs leachate: a control group without inoculation of algae or bacteria (soil, S); a treatment group sprayed only with bacterial suspension (soil + bacteria, SB); a treatment group sprayed only with M. vaginatus CM01 (soil + M. vaginatus CM01, SM); a treatment group co-inoculated with both BSCs leachate and M. vaginatus CM01 (soil + M. vaginatus CM01 + bacteria, SMB); a treatment group inoculated only with Leptolyngbya sp. CT01 (soil + Leptolyngbya sp. CT01, SL); and a treatment group co-inoculated with Leptolyngbya sp. CT01 and biocrust leachate (soil + Leptolyngbya sp. CT01 + bacteria, SLB). By integrating 16S rRNA gene sequencing, neutral community modeling (NCM), and structural equation modeling (SEM), we dissected differences in Cyano-BSCs development, bacterial community composition, co-occurrence networks, and assembly mechanisms. Inoculation with M. vaginatus CM01 (SM, SMB) superiorly promoted Cyano-BSCs development: the SM group achieved the highest coverage (23.33%), while the SMB group showed marked increases in organic matter (OM, 4.10 g·kg⁻¹) and chlorophyll a (Chla, 13.40 μg·g⁻¹), alongside a >5-fold rise in bacterial, cyanobacterial, and nitrogen-fixation gene abundances versus controls. The mechanism centers on extracellular polymeric substances (EPS) secreted by M. vaginatus, which homogenized the microenvironment, suppressed stochastic bacterial dispersal (NCM, SM: R² = 0.698), and enhanced deterministic selection. This process forged a highly cooperative network (89.74% positive links, average degree 34.71) that directionally enriched Cyanobacteria (relative abundance 40.40%). The Shannon index of Cyano-BSCs from the group (SMB) reached 7.72 ± 0.09, reflecting high microbial community diversity. SEM confirmed M. vaginatus directly regulated bacterial assembly (path coefficient = 0.59, p < 0.05) and indirectly improved the soil environment (path coefficient = 0.64, p < 0.05), establishing a “cyanobacteria-community-environment” feedback loop. Conversely, the Leptolyngbya sp. groups (SL, SLB), despite enriching nitrogen-fixing bacteria and fungi, exhibited low carbon fixation efficiency (notably 1.26 g·kg⁻¹ OM in SL) and lack of EPS; communities remained stochastic (NCM, SL: R² = 0.751) with no effective regulatory pathway—a pattern mirrored in S and SB groups. Our findings demonstrate that M. vaginatus acts as a core engineer of biological soil Cyano-BSCs formation via an “EPS-mediated habitat filtering—functional group enrichment—cooperative network assembly” cascade, enforcing deterministic community construction. Leptolyngbya sp., with limited niche-constructing ability, fails to exert comparable control. This work provides a targeted framework for the artificial restoration of Cyano-BSCs in arid zones. Full article

This paper presents the results of numerical and experimental studies of forced convection of water/EG-Al₂O₃ nanofluids through a horizontal stainless steel tube (8 mm inner diameter; 2000 mm length). As a base fluid, distilled water/EG mixture of three volume ratios (90:10, 80:20, and 60:40) is used. Nanoparticle mass concentrations are 0.1%, 1%, and 5%. The tested nanofluids are prepared by use of the two-step method. No dispersant is used to stabilize the suspension. Transition and turbulent flow regimes are tested. The commercial code Ansys Fluent 19.3 is used to conduct numerical simulations. A k-ε turbulence model with an expanded boundary layer function is adopted. A homogeneous nanofluid model is assumed, with thermophysical properties depending on the mean fluid temperature and nanoparticle concentration. The nanofluids are treated as incompressible Newtonian fluids. Both experimental and numerical studies showed an increase in the average Nusselt number with the addition of Al₂O₃ nanoparticles to each of the water/EG mixtures. However, the experimental results indicated that, at the maximum mass nanoparticle concentration of 5%, the Nusselt number increased by 42%, whereas the numerical simulations showed an increase of only 16% compared with the base fluid. Both experimental studies and numerical simulations show the flow resistance of the nanofluid increases with increasing nanoparticle concentration. Similarly to heat transfer, the numerical calculations predict lower pressure drops than those observed experimentally. For the maximum nanoparticle mass concentration of 5%, the experimental results indicate an increase in nanofluid flow resistance of about 95%, while numerical simulations predict an increase of about 50%, compared to the base liquid. The generalized correlation equations are proposed to calculate the average Nusselt number and the friction factor valid for the turbulent flow of water-based nanofluids and water/EG mixtures with a volumetric water fraction above 60% and a mass concentration of nanoparticles in the range of 0.1% ≤ φ_m ≤ 5%. Full article

Eggs are nutrient-dense yet recognized vehicles for Salmonella transmission. Because eggshells are easily contaminated during production and handling, washing is critical to reduce microbial load. Here, we evaluated the bactericidal efficacy of 150 ppm sodium hypochlorite (NaOCl) against Salmonella enterica subsp. enterica serovar Enteritidis (S. Enteritidis), serovar Typhimurium (S. Typhimurium), and serovar Thompson (S. Thompson) across washing temperatures and exposure times. Eggs were inoculated by immersion in 100 mL of a Salmonella suspensions (approximately 8 log CFU/mL) prepared separately for each serovar, air-dried for 1 h, and subsequently washed in 150 ppm NaOCl for 35, 40, 45, or 50 °C. Following washing, eggs were transferred to buffered peptone water, homogenized, and plated on xylose lysine deoxycholate agar to quantify the residual Salmonella populations on the eggshells. Washing with 150 ppm NaOCl significantly reduced counts (3–5 log) under all conditions versus unwashed eggs (p < 0.001). Maximum inactivation for S. Enteritidis occurred at 35 °C for 45 s (4.95 log), whereas S. Typhimurium was greatest at 45 °C for 45 s (5.48 log). In contrast, S. Thompson showed a nonmonotonic, time-dependent pattern, with maximum inactivation occurring at 40 °C for 45 s (5.17 log). Overall, 150 ppm NaOCl effectively reduced S. Enteritidis, S. Typhimurium, and S. Thompson on eggshells. Efficacy appeared to be serovar dependent, with maximal reduction occurring at different temperatures for each serovar. These findings support standardized egg-washing guidelines to minimize Salmonella transmission across the food supply chain. Full article

Dextrin-based nanosponges (D-NS) are promising candidates for oral drug delivery due to their biocompatibility, mucoadhesive properties, and tunable swelling behavior. In this study, pH-sensitive nanosponges were synthesized using β-cyclodextrin (β-CD), GluciDex^®2 (GLU2), and KLEPTOSE^® Linecaps (LC) as building blocks, crosslinked with pyromellitic dianhydride (PMDA) and citric acid (CA). The nanosponges were mechanically size-reduced via homogenization and ball milling, and characterized by FTIR, TGA, dynamic light scattering (DLS), and zeta potential measurements. Swelling kinetics, cross-linking density (determined using Flory–Rehner theory), rheological behavior, and mucoadhesion were evaluated under simulated gastric and intestinal conditions. The β-CD:PMDA 1:4 NS was selected for drug studies due to its optimal balance of structural stability, swelling capacity (~863% at pH 6.8), and highest apomorphine (APO) loading (8.23%) with 90.58% encapsulation efficiency. All nanosuspensions showed favorable polydispersity index values (0.11–0.30), homogeneous size distribution, and stable zeta potentials, confirming suspension stability. Storage at 4 °C for six months revealed no changes in physicochemical properties or apomorphine (APO) degradation, indicating protection by the nanosponge matrix. D-NS exhibited tunable swelling, pH-responsive behavior, and mucoadhesive properties, with nanoparticle–mucin interactions quantified by the rheological synergism parameter (∆G′ = 53.45, ∆G″ = −36.26 at pH 6.8). In vitro release studies demonstrated slow, sustained release of APO from D-NS in simulated intestinal fluid compared to free drug diffusion, highlighting the potential of D-NS as pH-responsive, mucoadhesive carriers with controlled drug release and defined nanoparticle–mucin interactions. Full article

Cracks inevitably develop in the pylon structures of suspension bridges due to external forces such as wind loads. Cracks are a primary cause of torsional damage to the key supporting structures of suspension bridges. Therefore, torsional fracture analyses are vitally important for evaluating the safety of bridge structures. In this study, we simplified the tower structure of a suspension bridge as a homogenous cylinder. We then employed the boundary integral equations for a cylinder with edge cracks to investigate the singularity features at the crack tip. The boundary element-based method was subsequently used to divide the boundary into several elements, and different interpolation functions were adopted to compute the stress intensity factor at the crack tip. Torsional stiffness and stress intensity factor calculations were conducted for cylinders with straight and polyline edge cracks. The results were compared with the results reported in the existing literature, and the accuracy and reliability of the calculation method were validated. Finally, the numerical simulation of the torsional fracture behavior of cylinders with edge cracks under various wind loads was conducted. The maximum allowable crack lengths of a cylinder under different wind grades were acquired, further demonstrating the feasibility and practicality of the boundary element calculation method for practical applications in bridge engineering. Full article

Alginate aerogels are attractive candidates for biomedical scaffolds because they combine high mesoporosity with biocompatibility and can be processed into open, interconnected macroporous networks suitable for tissue engineering. Here, we systematically investigate how CO₂-induced foaming parameters govern the hierarchical pore structure of alginate aerogels produced by subsequent supercritical CO₂ drying. Sodium alginate–CaCO₃ suspensions are foamed in a CO₂ atmosphere at 50 or 100 bar, depressurization rates of 50 or 0.05 bar·s⁻¹, temperatures of 5 or 25 °C, and, optionally, under pulsed pressure or with Pluronic F-68 as a surfactant. The resulting gels are dried using supercritical CO₂ and characterized by micro-computed tomography and N₂ sorption. High pressure combined with slow depressurization (100 bar, 0.05 bar·s⁻¹) yields a homogeneous macroporous network with pores predominantly in the 200–500 µm range and a mesoporous texture with 15–35 nm pores, whereas fast depressurization promotes bubble coalescence and the appearance of large (>2100 µm) macropores and a broader mesopore distribution. Lowering the temperature, applying pulsed pressure, and adding surfactant enable further tuning of macropore size and connectivity with a limited impact on mesoporosity. Interpretation in terms of Peclet and Deborah numbers links processing conditions to non-equilibrium mass transfer and gel viscoelasticity, providing a physically grounded map for designing hierarchically porous alginate aerogel scaffolds for biomedical applications. Full article