The valorization of lignocellulosic waste for biomedical applications has attracted considerable interest due to its sustainability and cost-effectiveness. In this study, lignin was extracted from spent coffee grounds using the soda pulping method and employed as a raw material for the preparation of methylene blue (MB)-loaded nanoparticles. The nanoparticles were fabricated via nanoprecipitation which a simple, scalable, and drug delivery-compatible method, using different lignin concentrations and volume ratios to identify the formulation that achieves the smallest particle size with maximum drug loading. Characterization results revealed that the nanoparticles were spherical, monodisperse, with an average size of 160 nm, and formed a stable aqueous suspension due to a zeta potential of-33.5 mV. Drug release studies indicated slower release under acidic conditions compared to neutral pH. Despite limited release, the nanoparticles retained the ability to generate reactive oxygen species (ROS) under light irradiation, as confirmed by the time-dependent decrease in DPBF absorbance. These findings suggest that lignin nanoparticles derived from coffee waste are promising candidates as photosensitizer carriers, and future studies are planned to evaluate their biocompatibility and in vitro therapeutic efficacy.
Background: Despite growing interest in artificial intelligence (AI)-mediated second or foreign language (L2) learning, little is known about the role of AI-driven informal digital learning of English (AI-IDLE) in shaping learners' communicative intention and motivation. Furthermore, how L2 learner traits such as grit may influence the relationship between AI-IDLE and communicative outcomes remains largely underexplored.Purpose: This study examined the association between AI-IDLE and two communicative variables - L2 willingness to communicate (WTC) and speaking motivation - with a particular focus on the mediating role of L2 grit.Methods: Participants were 244 English as a foreign language (EFL) learners (123 males, 121 females). Structural equation modeling was employed to examine the direct and indirect associations among AI-IDLE, L2 grit, WTC, and L2 speaking motivation.Results: Findings revealed that AI-IDLE significantly and directly predicted grit and WTC but not speaking motivation. L2 grit emerged as a strong predictor of both WTC and speaking motivation, and functioned as a full mediator in the relationships between AI-IDLE and the two communicative outcomes.Conclusion: These results highlight L2 grit as a key factor linking AI-driven informal learning with learners' communicative readiness and motivation, suggesting that fostering grit may maximize the benefits of AI tools for L2 learning.
LuFeO3 (LFO) is a perovskite oxide with promise for optical and electroceramic applications. In the present study, LFO and Co-substituted compositions (LFO, LuFe0.95Co0.05O3, and LuFe0.90Co0.10O3) were synthesized by a conventional solid-state route and characterized by SEM, Raman spectroscopy, diffuse reflectance, and broadband dielectric/impedance measurements. Co substitution alters the powder microstructure, yielding more irregular agglomerates composed of finer sub-units than undoped LFO. Dielectric spectra showed that the loss tangent (tanδ), the dissipation factor, of investigated samples was below 1 over the studied temperature–frequency window. It was seen that Co substitution decreased dielectric loss in the mid-to-high frequency region but raised low-frequency loss at advanced temperatures. The real part of impedance Z^' declined with both temperature and frequency, and Nyquist plots displayed depressed arcs, indicating non-Debye behavior with distributed grain and grain-boundary contributions. Arrhenius analysis of relaxation maxima yielded activation energies of ∼ 0.32–0.76 eV, consistent with oxygen-vacancy energies. Raman spectra revealed Co-induced lattice perturbations, including mode broadening/attenuation and red-shifts in the 200–600 cm− 1 range, together with a strengthened stretching feature near 600–650 cm− 1. Kubelka–Munk analysis was utilized to determine the band gaps of the studied samples, 2.19 eV (LFO), 2.29 eV (5
Co0.25Ni0.25Zn0.25Cu0.25AgxFe2-xO4 (0.00 ≤ x ≤ 0.10) nanospinel ferrites (Ag → CoNiZnCu (x ≤ 0.10) NSFs) have been synthesized via a one-pot sol–gel method. XRD analysis was applied to prove the phase formation for each product. The morphologies were confirmed via SEM/TEM. This study introduced a detailed analysis of the electrical and dielectric properties of ion-substituted spinel ferrites. AC/DC conductivity and complex impedance spectroscopy were both used to understand how substitution of Ag+ affects the charge-transport properties of these (NSFs). The unsubstituted NSF (x = 0.00) had very high resistivity (GΩ range) and was found to be mainly affected by one process of relaxation that occurred due to high resistive grain boundaries. After substitution with Ag, the DC conductivity increased dramatically by several orders of magnitude, which correlated with a massive reduction in resistance of the grain boundaries. The overall electrostatic and dielectric properties of these NSFs changed drastically with Ag+ ion substitution as well; this change was due to the presence of the effect known as colossal permittivity (ϵ′ > 104), which is explained by the Maxwell–Wagner theory of interfacial polarization. All types of analysis (using both the complementary impedance and electric modulus formalisms, including Nyquist plots) proved that by separating the different electrical responses from the grains and grain boundaries of the substituted NSFs, these materials are heterophase-natured. Therefore, it can be concluded that Ag + ion substitution is a very effective way to tune the properties of grain boundaries, resulting in a measurable difference in the total electrical/dielectric response of the NSFs.
Fatty acids have been linked to attention-deficit/hyperactivity disorder (ADHD), but the biological basis of this association remains unclear. This study examined dietary and plasma fatty acid profiles and fatty acid desaturase-2 (FADS2) in children with ADHD. This cross-sectional study included 85 children with ADHD and 85 controls aged 6–12 years. ADHD symptoms were assessed using the Conners’ Parent Rating Scale-Revised: Short Form (CPRS-R: S). Dietary fatty acid intake was estimated from three non-consecutive 24-hour recalls. Plasma fatty acids were measured by GC-MS. Plasma FADS2 protein levels were quantified by ELISA, and FADS2 mRNA expression was assessed by real-time PCR. Principal component analysis (PCA) was used to derive fatty acid components, followed by structural equation modeling (SEM) to evaluate associations with ADHD symptom severity. Children with ADHD showed a greater relative dietary contribution of omega-6 fatty acids and total PUFAs, higher plasma LA levels and omega-6/omega-3 ratio, and lower plasma MUFAs, GLA, and docosanoic acid than controls. Plasma FADS2 protein levels were numerically higher but not significantly different, whereas relative FADS2 mRNA expression was lower in the ADHD group. In SEM, greater ADHD symptom severity was associated with a PCA-derived component characterized by higher LA and omega-6/omega-3 ratio together with lower nervonic acid. Children with ADHD differed from controls across multiple dietary, plasma, and FADS2-related fatty acid measures, particularly those related to omega-6 balance. ADHD symptom severity was also associated with a multivariable fatty acid profile.
