Search Results (1,657)

Background and Objectives: The main neurodegenerative diseases (NDs)—Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS)—represent a growing global health burden with no available disease-modifying therapies. Curcumin, a polyphenol from Curcuma longa, is a promising candidate owing to its pleiotropic antioxidant, anti-inflammatory, and neuroprotective profile observed mainly in preclinical models, but the poor oral bioavailability (<1%) and negligible BBB penetration (<0.1%) have substantially limited curcumin’s clinical translation. The objective of this work was to critically examine the therapeutic potential of curcumin in NDs, focusing on advanced drug delivery systems (DDSs) designed to overcome its pharmacokinetic barriers. Methods: This is a narrative, non-systematic review of PubMed/MEDLINE, Scopus, and Web of Science. The review is organized around five complementary thematic areas selected to span the full translational pipeline of curcumin in neurodegeneration, from mechanistic rationale to clinical applicability: (1) molecular mechanisms, addressing the pleiotropic activities that justify therapeutic interest; (2) pharmacokinetic barriers, the principal obstacle to clinical translation; (3) the evolution of drug delivery systems (DDSs), documenting the technological strategies developed to overcome these barriers; (4) disease-specific applications, evaluating the available evidence across the four main NDs; and (5) translational limitations, identifying the methodological and regulatory gaps that must be closed to enable clinical implementation. Results: Curcumin exhibits neuroprotective activity in preclinical models of the four NDs analysed, acting on six interconnected mechanisms and the gut–brain axis. Four generations of DDSs have been developed, from phytosomes and clinically used lipid dispersions (Meriva^®, BCM-95^®, Longvida^®, and Theracurmin^®) to fourth-generation systems (biomimetic nanoparticles, MOFs, microneedles, 3D scaffolds, hydrogels, and carbon dots) that substantially increase the bioavailability in preclinical studies. Combination strategies, such as curcumin with resveratrol and dutasteride, show preliminary clinical signals in ALS. However, clinical translation remains limited: over 80% of positive animal findings have not been replicated in humans, formulation characterization is frequently incomplete, and most trials lack CNS-exposure biomarkers. Importantly, most of the reported bioavailability claims are based on total curcumin measurements (parent aglycone plus its inactive Phase II conjugates) rather than the active aglycone alone, a methodological limitation that should be considered when interpreting the magnitude of the bioavailability improvements reported for novel formulations. Conclusions: Curcumin exhibits pleiotropic neuroprotective activity in preclinical models of AD, PD, MS, and ALS, mediated by interconnected antioxidant, anti-inflammatory, anti-amyloidogenic, mitochondrial, and gut–brain axis mechanisms. However, its poor systemic bioavailability (<1%), minimal blood–brain barrier penetration, and extensive first-pass metabolism have limited clinical translation. Advanced drug delivery systems (including lipid-based carriers (liposomes, solid lipid nanoparticles, and nanostructured lipid carriers), polymeric nanoparticles (PLGA and chitosan), and bioinspired vesicles (exosomes)) are essential in order to overcome these barriers. Nevertheless, the formulation heterogeneity, limited long-term safety data, and reliance on preclinical models remain major obstacles; a definitive clinical translation will therefore require well-characterized formulations validated in phase II/III trials with cerebrospinal fluid exposure biomarkers, the pharmacokinetic monitoring of active aglycone (rather than total curcumin including inactive conjugates), and adaptive trial designs in neurological populations. Full article

This study investigates the microstructural, tribological, and corrosion properties of electrodeposited Zn-Co nanocomposite coatings reinforced with graphene and TiO₂ nanoparticles on Selective Laser-Melted (SLM) Ti6Al4V alloy. Systematic characterization using XRD, SEM, and Raman spectroscopy revealed that the incorporation of graphene and TiO₂ significantly refined the grain structure, resulting in a dense and defect-free surface morphology. Reciprocating wear tests demonstrated that the optimized hybrid coating (Zn-Co-GTi) exhibited superior tribological performance. Electrochemical impedance spectroscopy (EIS) tests conducted in simulated body fluid (SBF) at 37 °C demonstrated that the optimized hybrid coating (Zn-Co-GTi) also provided enhanced corrosion resistance. Specifically, the coefficient of friction decreased from 0.79 to 0.24, while the wear rate was reduced to 5.1 × 10⁻⁴ mm³/Nm. Electrochemical evaluations further confirmed a significant improvement in corrosion resistance, with the Zn-Co-GTi coating exhibiting the lowest corrosion current density (0.0059 μA cm⁻²) and the highest charge transfer resistance (Rct). However, increasing the reinforcement content beyond the optimum level resulted in partial nanoparticle agglomeration, leading to a slight deterioration in both tribological and corrosion performance. Overall, the optimized Zn-Co-Graphene-TiO₂ nanocomposite coating provides an effective and scalable surface engineering strategy for improving the durability and corrosion resistance of SLM-produced Ti6Al4V components for advanced engineering and biomedical applications. Full article

Ti6Al7Nb biomedical alloy is difficult to machine because its low thermal conductivity and high chemical reactivity promote heat accumulation, high cutting loads, and poor surface quality. This study evaluated the side milling performance of Ti6Al7Nb under dry machining, vortex tube cooling, and MWCNT-assisted nanoparticle minimum quantity lubrication (NMQL) to identify a more sustainable and effective machining strategy. Experiments were conducted using two cutting speeds and three feed rates, and machinability was assessed in terms of cutting temperature, resultant cutting force, surface roughness, Tol wear and tool life, chip morphology, and multi-criteria ranking. Compared with dry machining, vortex tube cooling provided the strongest thermal control, reducing cutting temperature by 25–36% compared with dry conditions, owing to the cold air stream generated by the Ranque–Hilsch effect. MWCNT-NMQL produced the greatest reductions in cutting force and surface roughness, with improvements of 7–28% and 10–20%, respectively, compared with dry conditions, due to improved lubrication, reduced adhesion, possible tribofilm formation, rolling/sliding effects of MWCNTs, and enhanced heat transfer. Chip morphology observations confirmed that both assisted environments improved chip formation compared with dry machining. The overall ranking identified vortex tube cooling at Vc = 30 m/min and f = 0.08 mm/rev as the best overall condition, while NMQL was more favorable for force reduction and surface finish improvement. The findings of this study provide practical guidance for the selection of sustainable and effective cutting strategies in the precision machining of biomedical titanium alloys. Full article

In this work, 1%Pd/γ-Al₂O₃ catalysts modified with poly(4-vinylpyridine) (P4VP), polyacrylamide (PAM), and polyacrylic acid (PAA) were synthesized and evaluated for allyl alcohol hydrogenation. The effect of P4VP content was systematically investigated by varying the polymer loading, followed by comparison of the catalytic properties of the modified catalysts with that of the unmodified 1%Pd/γ-Al₂O₃ catalyst. The synthesized catalysts were characterized by TGA, IR spectroscopy, XRD, TEM, XPS, SEM/EDS, and viscosimetry to evaluate their structural, morphological, surface, and elemental properties. TEM analysis revealed that low P4VP loading preserved small Pd nanoparticles (3.9 nm), whereas higher polymer loadings promoted particle growth to 7.7 nm. All catalysts achieved complete conversion of allyl alcohol. At 5 wt.% polymer loading, the P4VP-modified catalyst exhibited a slightly higher hydrogenation rate than the PAA- and PAM-modified catalysts. Decreasing the P4VP content from 5 to 3 and 1 wt.% increased the hydrogenation rate from 8.3 × 10⁻⁶ to 13.9 × 10⁻⁶ and 22.9 × 10⁻⁶ mol/s, respectively, while propanol selectivity increased from 64 to 65 and 71%. The 1%Pd–P4VP(1%)/γ-Al₂O₃ catalyst exhibited higher catalytic activity than the unmodified 1%Pd/γ-Al₂O₃ catalyst and maintained good stability over 20 consecutive substrate additions. These findings demonstrate that the catalytic behavior of polymer-modified 1%Pd/γ-Al₂O₃ catalysts depends on the balance between polymer loading, Pd nanoparticle size, and active site accessibility. Full article

Aluminum nanoparticles (ANPs) possess a core–shell structure, yet the coupled roles of atomic stress and interfacial charge transfer in their slow-heating oxidation remain elusive. This study employs ReaxFF molecular dynamics simulations to investigate the oxidation of six core–shell ANPs with different particle sizes (5–10 nm) and shell thicknesses (0.5–2.0 nm) from 300 K to 1400 K. Results reveal that the stress evolution dictates the oxidation pathway. Thin shells (0.5–1.0 nm) undergo a compressive-to-tensile stress transition, leading to shell rupture at ~1060 K and subsequent outflow and rapid oxidation of Al into clusters, while thick shells (1.5–2.0 nm) maintain compressive confinement, preventing rupture but resulting in incomplete oxidation (58–84%). Mean squared displacement indicates earlier atomic diffusion onset for thin-shell particles (~7 ps) compared to thick-shell ones (~15 ps). Significantly, interfacial charge redistribution provides the electronic driving mechanism: thin shells facilitate charge homogenization and electron loss, lowering diffusion barriers, whereas thick shells sustain distinct charge separation, impeding atomic migration. These findings provide a theoretical basis for the atomic-scale stress–charge–diffusion coupling mechanism, offering crucial insights for the safety assessment and structural design of oxidation-resistant ANPs. Full article

This study aimed to develop polymer matrix nanocomposites reinforced with Al₂O₃ nanoparticles to enhance the mechanical properties of PMMA. The composite was fabricated via friction stir processing (FSP) to ensure the homogenous dispersion of Al₂O₃ nanoparticles in the polymer. A grid of 5 holes in a 7 × 7 mm² area was made in which the hole diameter was varied from 1.77 mm to 2.28 mm to obtain different volume fractions of reinforcement ranging from 15% to 25%. The holes were made with a depth of 3 mm in a 4 mm-thick PMMA sheets. After packing the Al₂O₃ powder in the holes, a 2 mm-thick PMMA sheet was used as a cover to prevent the sputtering of nanoparticles. A number of FSP parameters were examined. The tool rotation rates ranged from 800 to 1200 rpm, traverse speeds of 25 and 50 mm/min, and tool tilts of 1 and 2° were used. A soft paraffin (Vaseline) layer was used on the top surface to prevent severe shoulder friction with the PMMA plate, which caused severe wear and thinning on the surface. For the developed PMMA/Al₂O₃ nanocomposites, the surface quality, SEM microstructure, impact energy, and transverse hardness were investigated. Good surface quality and dispersion of nanoparticles were attained by employing adequate processing conditions. The experimental results indicated that as the nanoparticle percentage increased, impact energy, hardness, and tensile strength increased, reaching 2 kJ/m², 14.7 HV, and 52.1 MPa at a nanoparticle concentration of 25%. This means that the polymer ceramic composite’s toughness, hardness, and tensile strength are higher than those of unprocessed PMMA by 66%, 33%, and 23%, respectively. Full article

Cellulose insulation paper used in oil-immersed power transformers is vulnerable to molecular chain loosening and aging-product transport under thermal and electrical stresses. Nanomodification is a promising route for improving insulation-paper stability, but the atomistic mechanisms by which KH550-grafted oxide nanoparticles regulate cellulose structure and aging-molecule mobility under an external electric field remain insufficiently clarified, particularly when the role of oilpaper insulation aging and oil-contact environments is considered. In this work, pristine cellulose and cellulose modified with KH550-grafted SiO₂ and Al₂O₃ nanoparticles were investigated using molecular dynamic simulations at 343 K under a uniform electric field of 0.01 V/Å (100 kV/mm) applied along the Z-axis. Based on the MSD and apparent transport-parameter results, nanomodification reduced the MSD-derived apparent coefficients of H₂O and CO₂ by 33.7–51.9%. The external field produced apparent directional transport bias, with Z/X apparent-coefficient ratios of 2.21 for H₂O and 2.02 for CO₂ in pristine cellulose. These ratios decreased to 1.62 and 1.51, respectively, in the KH550–Al₂O₃ model. Interfacial interaction energy analysis showed that the KH550–SiO₂ interface became more strongly bound under the field (−240.50 to −252.13 kcal/mol), whereas the KH550–Al₂O₃ interface remained nearly unchanged (−541.65 to −538.81 kcal/mol). Because the two nanomodified systems use different nanoparticle loadings and KH550 grafting ratios, cross-system differences are interpreted as model-specific outcomes rather than effects attributable only to nanoparticle chemistry. These results indicate that KH550-grafted nanoparticles may help maintain cellulose packing under the modeled conditions and suppress aging-molecule mobility in the simulated cellulose matrix, while the conclusions should be interpreted as atomistic simulation evidence rather than direct proof of long-term transformer reliability. Full article

Inorganic nanofillers have been incorporated to enhance the electrical treeing resistance of polymers. However, the influence of nanofiller shape and distribution remains not fully understood, thereby limiting the advancement of new insulation design strategies. This work presents a phase-field model to simulate the propagation of electrical tree in nanocomposites and quantitatively compare the effectiveness of different filling schemes. The damage status of insulation is described with a spatially and time dependent continuous variable, and the evolution of damage phase is modeled with the kinetic equation. The results indicate that nanofillers act as physical barriers to electrical-tree growth. Due to the competition between the hindrance effect and electric-field enhancement of nanofillers, the nanocomposite containing 8 vol% Al₂O₃ nanoparticles exhibits the optimal electrical-treeing resistance, with the breakdown time increasing from 767.5 s for neat PE to 827.1 s, corresponding to an improvement of 7.77%. The electrical-tree resistance is closely related to the shape and orientation of the nanofillers. Compared with neat PE, randomly distributed and parallel nanosheets increase the breakdown time by 12.04% and 27.00%, respectively, and exhibit stronger inhibition of electrical-tree growth than nanoparticles and nanofibers. High-throughput computations are further performed to analyze the effects of nanofiller shape and orientation on electrical-tree characteristics. When the electrical-tree propagation direction is perpendicular to the nanosheets, increasing the aspect ratio from 2 to 12 raises the normalized breakdown time from 1.07 to 1.36. Full article

Background/Objectives: Nanotechnology has become a transformative area in modern dentistry, providing new opportunities for better diagnosis, targeted drug delivery, improved restorative materials, antimicrobial treatments, and tissue regeneration. This scoping review outlines the scope, key developments, and future directions of nanotechnology use across all dental specialties, highlights emerging innovations, and identifies major translational challenges and research priorities. Methods: This review followed the Joanna Briggs Institute (JBI) methodology for scoping reviews and adhered to the PRISMA-ScR guidelines. These guidelines, originally by Arksey and O’Malley (2005) and later updated by Levac et al. (2010) and Peters et al. (2020, 2021), guided the process. The Population, Concept, and Context (PCC) framework guided the eligibility criteria. Included studies were primary research or reviews reporting nanotechnology applications in any dental specialty, published in English, with no date restriction. Excluded were non-peer-reviewed sources, conference abstracts without full text, studies unrelated to dental applications, and non-English publications. A comprehensive literature search was conducted across PubMed/MEDLINE, Scopus, and Web of Science. After screening titles and abstracts and reviewing full texts, 133 studies were included. Results: The included studies covered a wide range of fields such as restorative dentistry, implantology, periodontology, endodontics, drug delivery, tissue regeneration, oral diagnostics, antimicrobial applications, prosthodontics, orthodontics, and emerging technologies like nanorobotics and graphene-based systems. The most commonly reported nanomaterials were silver nanoparticles (AgNPs), calcium phosphate nanoparticles (CaP NPs), and polymeric nanoparticles such as PLGA and chitosan. Additionally, there was a notable increase in publications starting from 2019. Conclusions: Nanotechnology offers transformative possibilities in every area of dentistry. Nonetheless, challenges such as nanotoxicology safety, regulatory alignment, and effective clinical application need resolution. Essential steps include standardized characterization, gathering long-term safety data, and establishing international regulatory standards to ensure safe adoption of nano dentistry. Full article

JP-10 is a pivotal high-density hydrocarbon fuel for advanced aerospace propulsion systems. Doping aluminum nanoparticles to prepare nanofluid fuels is a promising route to enhance its energy density and combustion performance, yet the droplet formation mechanism of such multiphase fuels remains poorly understood, hindering single-droplet combustion research and atomization system optimization. This work constructed a piezoelectric drop-on-demand (DOD) monodisperse droplet generation platform integrated with phase Doppler anemometry (PDA) and high-speed imaging. Using Al/JP-10/OA nanofluids with aluminum mass fractions of 0.1 wt. %, 0.5 wt. % and 1.0 wt. %, we systematically explored the effects of liquid flow rate, driving frequency and particle concentration on droplet size, size uniformity and ejection velocity. In this work, Al/JP-10/OA nanofluids with aluminum mass fractions of 0.1 wt. %, 0.5 wt. % and 1.0 wt. % were tested under liquid flow rates of 1.1–1.5 mL/min and driving frequencies of 10–50 kHz, with measured droplet diameter ranging from 241.04 μm to 292.26 μm and ejection velocity ranging from 1.65 m/s to 2.45 m/s. The results demonstrate that average droplet diameter increases linearly with flow rate and decreases monotonically with driving frequency. Compared with the 0.1 wt. % nanofluid, the 1.0 wt. % nanofluid shows a 4.4% larger droplet diameter and 12.1% lower ejection velocity, while the 0.1 wt. % sample retains excellent monodispersity with a size Span below 0.098. The multi-scale regulation mechanisms involving viscous variation, shear-thinning rheology and particle agglomeration are further clarified. This study provides fundamental data and theoretical support for atomization design of nanofluid aviation fuels. Full article

This reply presents a point-by-point response to the comments received from Pantokratoras in our previously published research article. The comments highlighted that the values of electrical conductivity assigned to alumina (Al₂O₃), silicon dioxide (SiO₂), and titanium dioxide (TiO₂) nanoparticles were not appropriate and the experimental value of the Prandtl number for blood should remain within the range of 29–32. In response the electrical conductivity values for each nanoparticle were corrected and revised the Prandtl number values accordingly. The recomputed findings revealed that only small changes appeared in quantitative results while the overall trends and insights remained same. Full article

Phosphorus is recognized as one of the primary contributors to eutrophication in freshwater ecosystems. Among the various strategies proposed to mitigate its impact, adsorption-based removal has emerged as one of the most widely adopted and effective approaches globally. In this study, Zn/Al-layered double hydroxides (LDHs) were synthesized by varying the molar ratio of cations to obtain materials with different cationic densities. The materials were additionally modified via a co-precipitation method to incorporate titanium dioxide (TiO₂) or zinc oxide (ZnO) nanoparticles to synthesize novel composite nanomaterials aimed at phosphate species removal from aqueous solutions. The resulting materials demonstrated orthophosphate adsorption capacities exceeding 45 mg/g in most cases. Adsorption kinetics were evaluated using pseudo-first order and pseudo-second order models, while equilibrium data were fit to the Langmuir and Freundlich isotherms. The results indicated that the pseudo-second order model and the Langmuir isotherm provided the best fit, suggesting that the adsorption process is predominantly chemisorption occurring on a homogeneous monolayer. These findings highlight the potential of TiO₂/ZnO–LDH composites as efficient adsorbents for phosphorus remediation in aquatic environments. Full article