Search Results (1,817)

The antimicrobial effect of Eucalyptus radiata essential oil nanoemulsion (EON) on Staphylococcus aureus and spoilage microorganisms was evaluated on fresh beef chunks during cold storage at days 0, 2, 4, 6, and 8. For this purpose, nanoemulsion was prepared using 2% eucalyptus oil combined with high methoxyl pectin, glycerol, and Tween 80, employing high shear force. Then the following were evaluated: (1) the essential oil’s chemical profile and in vitro antioxidant and antimicrobial capacities; (2) the nanoemulsion characteristics; and (3) the microbial counts of the beef treatments. The results showed that the essential oil’s primary components were o-cymene (45.4%), 2-bornene (26.29%), 1,8-cineole (11.31%), and α-pinene (9.25%). The EON had a particle size of 52.04 nm and a zeta potential of −9.16 mV. The in vitro studies revealed that both the essential oil and its nanoemulsion demonstrated significant antibacterial activity. Similarly, in in situ examinations, when the meat samples were spiked with S. aureus (0.1 × 10⁸ CFU/mL), the EON-treated meat samples had significantly (p ≤ 0.05) lower microbial counts than the untreated meat samples throughout the storage period; the difference between the treatments ranged between 1.62 and 2.44 log CFU/g. Additionally, the EON exhibited excellent antimicrobial efficacy against spoilage microorganisms on beef pieces during shelf life. On day 4, the maximum inhibitory activity was observed against total coliform, Pseudomonas spp., and yeast in reductions of 1.96, 2.09, and 2.18 log CFU/g in microbial counts, respectively. Moreover, application of meat samples with the EON delayed spoilage by 4 days. Therefore, the results of this study showed that coating beef chunks with the EON enhanced both product safety and shelf life. Full article

To evaluate the potential of defatted and dephenolized walnut meal as a modified functional food ingredient, this study examined how ball milling and processing time affect its structural, physicochemical, and functional properties. Walnut meal was ball-milled for 5, 10, 15, and 20 h. Ball milling increased the lightness and whiteness, reduced particle size, and broadened the particle size distribution into a characteristic three-peak pattern. Scanning electron microscopy revealed the progressive formation of flake-like surface structures. With increasing milling duration, free sulfhydryl groups, surface hydrophobicity, and solubility were increased, while dynamic surface tension decreased, leading to improved foaming capacity and foaming stability. SDS-PAGE confirmed that the primary structure remained unchanged, while Fourier transform infrared spectroscopy indicated a decrease in α-helix and β-sheet contents and an increase in random coil structures. X-ray diffraction revealed a reduction in the diffraction peak at 2θ = 8.963°, and differential scanning calorimetry showed irregular changes in the thermal stability with ball milling time. Overall, increasing ball milling time is beneficial for improving the functional properties of walnut meal, providing a preliminary theoretical reference for the potential application of walnut powder in foods with specific functional properties, such as aerated foods. Full article

This study investigates the decay-like degradation mechanisms of the matrix material in composite insulators, focusing on the pronounced influence of humid environments on partial discharge (PD) characteristics and degradation pathways. A sealed chamber discharge platform was established, integrating PD signal monitoring, surface characterization, and gas chromatography-mass spectrometry (GC-MS) with molecular network analysis to examine the synergistic effects of thermal influences from PD and active atmospheric particles at humidity levels of 0% RH, 50% RH, and 100% RH. Results show that dry conditions favor high-energy, low-repetition-rate discharges, promoting cleavage and recombination of high-bond-energy bonds (e.g., benzene rings and (α)C–O), yielding primarily long-chain carboxylic acids (C9 and above). In contrast, humid conditions shift to low-energy, high-repetition-rate discharges, with water vapor decomposition generating highly oxidizing hydroxyl radicals (·OH). These facilitate selective scission of lower-bond-energy (β)C–O bonds and deep oxidation, significantly increasing short-chain dicarboxylic acids—especially oxalic acid—whose acidity and water solubility are nearly an order of magnitude higher than in dry environments, becoming the dominant acidic products. The work demonstrates that many PD-generated organic acids act as intrinsic corrosive agents in insulating systems, independent of ambient nitric acid. This elucidates, at the reaction pathway level, how high humidity modulates PD to enhance corrosive acid production, providing a microchemical basis for understanding regional decay-like failure patterns in composite insulators. Full article

The effects of Mn/RE (Nd, Gd) multi-modification on the microstructure and high-temperature compressive creep properties of Mg–8.0Al alloys were investigated. The dominant intermetallic phases in the as-cast microstructure are β-Mg₁₇4Al₁₂, Al₂(Gd,Nd), Al₁₁(Gd,Nd)₃, Al₈(Gd,Nd)Mn₄, and Al₁₀Mn₂(Gd,Nd). The detailed structures of various intermetallics were revealed by TEM; the results indicate that Mn addition promotes grain refinement and facilitates the precipitation of lath-shaped and spherical β-Mg₁₇Al₁₂ in as-cast Mg–Al–RE alloys, resulting in increases in the tensile strength and elongation of the 1.0Mn alloy by 26.5% and 92.1%, respectively. Additionally, thermally stable micron-scale Al₈(Gd,Nd)Mn₄ and Al₁₂(Gd,Nd)₂Mn₅, along with dynamically precipitated spherical nano-sized AlGd and AlNd particles in the α-Mg matrix, were innovatively observed in compression-crept specimens tested at 200 °C and 60 MPa; these phases play a key role in improving high-temperature creep resistance. A significant finding is that excessive Mn addition deteriorates creep performance, which is attributed to excessive grain refinement and the consequent increase in the contribution of grain boundary sliding during creep. However, the negative effect of grain boundary sliding—caused by grain refinement—on creep performance can be balanced by the strengthening effect of Al–Mn–Gd phases and the dynamic precipitation of nanoscale Al–RE particles. This paper provides new insights for designing Mg–Al–Nd–Gd–Mn alloys with both excellent high-temperature creep resistance and significantly enhanced mechanical properties. Full article

PVP-stabilized silver nanoparticles (Ag NPs) were functionalized with sildenafil (Sil), leading to spherical NPs (Ag@Sil NPs) with a size of about 30 nm as observed through transmission electron microscopy and dynamic light scattering. Fourier-transformed IR spectroscopy confirmed the covering of the particles with Sil. The Ag@Sil NPs were incorporated into a 0.1 wt% ointment and tested for the treatment of acute anal fissures in a preliminary medical study involving 50 patients. Typical symptoms such as pain, bleeding, itching, and mass sensation were improved in the intervention group with no adverse effects. Molecular docking showed strong interactions with docking scores slightly above −10 kcal/mol between sildenafil and two different model complexes [Ag–Sil]⁺ for the Ag-bound sildenafil with either piperazine-N- or pyrazole-N-bound Ag⁺ ions and the muscarinic M2 and the nicotinic acetylcholine α3β4 receptor, which are both involved in anal sphincter regulation. All three showed superior binding compared with nitroglycerin and L-arginine. The residue analysis revealed a higher number of relevant interactions for the sildenafil and the two Ag⁺ complexes, compared to nitroglycerin and L-arginine, fully in line with the differences in the docking scores. Full article

Dietary fibers are valuable food components with documented health benefits, yet their native compact and highly crystalline structures often result in low water hydration, poor adsorption capacity, and limited bioactivity. Chemical modification offers a promising strategy to overcome these functional limitations by disrupting the dense structure and exposing active groups. This study aimed to investigate the effects of acid modification on the physicochemical properties of soybean and citrus dietary fibers and to evaluate the performance of the modified fibers in probiotic-fermented soy protein gels. Compared with native fibers, modified fibers exhibited reduced particle size, rougher and more porous microstructures, and increased exposure of hydroxyl groups. Consequently, they showed significantly (p < 0.05) enhanced hydration capacity (increased by 92–541%), antioxidant activity (increased by 15–65%), cholesterol adsorption (increased by 16–75%), and α-amylase inhibition (increased by 26–62%). When incorporated into soy protein-based gels, the modified fibers, particularly those from soybean, lowered gel pH, increased water holding capacity, gel strength, apparent viscosity, and storage modulus, while reducing strain, indicating improved gel network integrity. These findings indicate that acid modification effectively unlocks the functional potential of dietary fibers, positioning the modified fibers, especially from soybean, as promising prebiotic ingredients for plant-based fermented gel products. Full article

Ti–6Al–4V is the primary titanium alloy for aerospace, biomedical, and additive manufacturing applications; however, the high cost of powders produced by atomization limits their widespread adoption. This study aims to develop a cost-effective method for producing chemically homogeneous pre-alloyed Ti–6Al–4V powders from titanium sponge. A combined process is proposed, involving the hydrogenation of titanium sponge, mechanical alloying of the hydride phase with Al and V powders, and subsequent vacuum dehydrogenation. The formation of the brittle δ-TiH₂ phase facilitated intensive material comminution and effective distribution of the alloying elements. According to laser diffraction data, the median particle size decreased from 450 to 30–35 µm. X-ray diffraction (XRD) analysis confirmed the sequential α-Ti → δ-TiH₂ transition and the formation of a stable α + β two-phase structure characteristic of Ti–6Al–4V following dehydrogenation. SEM observations demonstrated that the final powders predominantly consist of individual fractured particles with limited hard agglomeration, favorable for powder flowability and compaction behavior. EDS analysis indicated a relatively homogeneous microscale distribution of Al and V without observable large-scale segregation. The synthesized powders exhibited low impurity levels, with O < 0.07 wt.% and H < 0.02 wt.%. The developed approach represents a promising and economical alternative to expensive atomization techniques for powder metallurgy and additive manufacturing. Full article

We present the results of applications of ATLAS2.0 to experimental data in this final part of our series of publications. ATLAS2.0 retrieves particle microphysical parameters from multiwavelength Raman and high-spectral-resolution lidar measurements of backscatter (β) coefficients at three wavelengths, i.e., λ = 355, 532, and 1064 nm, extinction (α) coefficients at two wavelengths, i.e., 355 and 532 nm, and particle linear depolarization ratios (PLDR, δ) at three wavelengths, i.e., 355, 532, and 1064 nm, so-called 3β + 2α + 3δ datasets. The explicit use of PLDRs is a novel feature compared to all previously developed lidar data retrieval algorithms. For the tests of ATLAS2.0, we use data that were taken with NASA Langley Research Center’s airborne high-spectral-resolution lidar 2 (HSRL-2). We show the results of two case studies. We compare the particle microphysical parameters and single-scattering albedo (SSA) retrieved with ATLAS2.0 to results obtained with the first version of ATLAS, our Tikhonov regularization algorithm (TiARA), and in situ observations carried out aboard an aircraft that followed the airborne HSRL-2 instrument. The solutions converge within the retrieval uncertainties of these techniques. The discrepancy between the measured and backcalculated, i.e., retrieved 3β + 2α + 3δ data on average stays below 10%. The difference between the retrieved and measured PLDRs is, on average, even less. This comparably good convergence of the optical datasets (experimental versus backcalculated) of both measurement cases can only be achieved if the investigated aerosol particles are analyzed on the basis of a sphere-spheroid mixture. Full article

This study presents a novel in situ reinforcement strategy for 17-4PH stainless steel by using Nb and Cr₃C₂ powders as precursors, addressing the challenge of poor particle dispersion and interfacial bonding in conventional ex situ ceramic additions. The coatings were systematically compared with 17-4PH coatings without the addition of a reinforcing phase. The results show that the coating without Nb addition is dominated by α-Fe martensite, exhibiting a coarse columnar/dendritic microstructure. After adding Nb and Cr₃C₂, the coating successfully forms in situ face-centered cubic NbC, with a significantly refined and uniformly distributed microstructure. The 10 wt.% Nb+Cr₃C₂ coating exhibits a refined microstructure with an average grain size reduced from 1.12 μm to 0.85 μm and a microhardness of 495.5 HV, representing an 86% increase over the substrate and a 34% improvement compared to the unreinforced coating. Friction–wear tests demonstrate that the composite coating reduces wear track width and depth by approximately 50% and 45%, respectively, compared to the substrate, with the wear mechanism transitioning from severe adhesive and fatigue wear to mild abrasive wear and localized micro-delamination. In situ synthesized NbC effectively optimizes the coating microstructure, enhances interfacial bonding, and markedly improves the hardness and wear resistance of 17-4PH coatings, providing theoretical and technical support for their engineering application under severe service conditions. Full article

The microstructural characteristics and precipitate features of titanium matrix composites (TMCs) are critical to tribological performance. In this study, TiCp/TA15 composites were fabricated via laser powder bed fusion (LPBF). The as-built composite was then heat-treated at 750 °C for 2 h to obtain a uniform duplex (α + β) microstructure with enhanced TiC precipitation, which was labeled as HT-750. The influence of the microstructural evolution on the tribological performance was systematically investigated. Compared to the as-built composite, the HT-750 composite exhibited a microhardness increase from 360.2 ± 6.4 HV to 459.2 ± 3.1 HV, a reduction in the friction coefficient from 0.649 ± 0.167 to 0.581 ± 0.111, and a decrease in the wear rate from 8.24 ± 0.44 × 10⁻⁴ mm³/(N·m) to 4.81 ± 0.39 × 10⁻⁴ mm³/(N·m), indicating a significant enhancement in wear resistance. This improvement is primarily attributed to the synergistic strengthening effect of the duplex matrix and TiC particles, which enhanced the load-bearing capability and suppressed surface plastic deformation. During the friction process, the dominant wear mechanisms of as-built and HT-750 composites evolved over time but exhibited distinct differences. The as-built composites were prone to continuous plastic deformation and damage accumulation, resulting in severe delamination, oxidative, and abrasive wear. Conversely, the HT-750 composites demonstrated higher resistance to plastic deformation and crack propagation, effectively mitigating interfacial shear and inhibiting damage evolution, with the wear mechanism being dominated by oxidative wear accompanied by abrasive wear and minor delamination. This work provides deep insights into the wear mechanisms of additively manufactured TMCs. Full article

To address the limited constraints of ground-based lidar with few channels in retrieving aerosol microphysical parameters in urban atmospheres, this study developed a method to retrieve aerosol volume size distribution and effective radius from a 355/532/1064 nm triple-wavelength elastic-scattering, single-polarization lidar system. The method uses 3β + 2α optical quantities as input constraints, applies Mie scattering theory as the forward model, parameterizes the volume size distribution with B-spline functions, and achieves stable solutions through Tikhonov regularization and cross-validation. To reduce uncertainties in prior parameters, including the complex refractive index, particle size range, and lidar ratio, an optimization strategy based on parameter search, retrieval reconstruction, and error minimization was introduced. Numerical simulations showed that the method reproduced the main features of a bimodal lognormal aerosol volume size distribution with good feasibility and stability. Two case studies further showed fine-mode dominance and decreasing extinction coefficient, depolarization ratio, and effective radius with height under good air quality conditions, but enhanced coarse-mode contribution and effective radius in the upper cloud-influenced layer under lightly polluted conditions, as inferred from the combined variations in RSCS, extinction coefficient, depolarization ratio, and effective radius. Full article

We present a novel algorithm for the retrieval of non-spherical particle microphysical parameters (PMP) from 3β + 2α + 3δ optical data taken with multiwavelength lidar. The 3β + 2α + 3δ optical datasets describe particle backscatter coefficients (β) at three wavelengths, λ = 355, 532, and 1064 nm, particle extinction coefficients (α) at two wavelengths, λ = 355 and 532 nm, and particle linear depolarization ratios (PLDR, δ) at three wavelengths, λ = 355, 532, and 1064 nm. The algorithm can be used for retrieving bimodal particle size distributions (PSDs). The PSDs can comprise mixtures of spheres and spheroids (SS). One or both modes can comprise spheroid-shaped particles or spherically shaped particles. The spheroids are used for approximating an arbitrary ensemble of non-spherical particles. The algorithm works on the basis of a combination of direct and analytical inversion methods. The algorithm uses the spheroid reference look-up table (RLUT) we developed and presented in part 1 of our research work. The algorithm uses constraints regarding the particle complex refractive index (CRI) and information on relative humidity (RH) in the atmosphere (in the case of aerosol lidar observation) for suppressing retrieval uncertainties. We carried out a numerical simulation study to evaluate the algorithm’s performance. In these numerical simulations, we considered perturbed synthetic 3β + 2α + 3δ optical data that mimic different organic carbon (OC)–dust (D) mixtures. Such mixtures are suitable examples for describing bimodal PSDs that consist of a fine mode of spherical particles and a coarse mode of non-spherical particles. The results of the numerical simulation show that (1) the PMPs of each mode of these particle mixtures can be found separately, (2) the mean retrieval errors of the effective radius, number, surface-area, and volume concentrations of these mixtures are 25%, 52%, 9%, and 28%, respectively, and (3) the mean retrieval error of single-scattering albedo (SSA) at 355 nm of these mixtures is as low as ±0.02. SSA retrieval accuracies at 532 and 1064 nm degrade because the complex refractive index (CRI) of OC and D particles depends on the measurement wavelength. In future studies, we will upgrade the algorithm such that it takes into account a spectrally dependent CRI. We also compare the results of our novel algorithm with our TiARA2.1 algorithm. The errors obtained from the TiARA2.1 algorithm are approximately three times larger compared to the errors we obtain with our novel ATLAS algorithm for the case of the OC-D mixtures considered in the present study. We explain the higher accuracy of the PMP retrievals by the use of three PLDRs and the extra constraints placed on CRI and RH. Full article

Bismuth oxide (Bi₂O₃) nanoparticles are attractive for biomedical and radiation-shielding technologies and can be further tailored through the addition of other metal oxides to address emerging needs such as antimicrobial resistance. This study investigated the effects of incorporating Fe₂O₃ and La₂O₃ on the structure, morphology, and antimicrobial performance of Bi₂O₃-based nanocomposites synthesized via a plant extract-assisted microwave–hydrothermal route using soapnut extract. XRD indicated that pure Bi₂O₃ (100B) comprised predominantly monoclinic α-Bi₂O₃ with coexisting metastable tetragonal β-Bi₂O₃. The addition of Fe (3F; Fe:Bi = 30:70) promoted β- Bi₂O₃ and formed BiFeO₃, while increasing La substitution (3L–20L) reduced the BiFeO₃ intensity and, beyond a threshold (≥7L), yielded distinct La₂O₃ peaks consistent with a La₂O₃–BiFeO₃–Bi₂O₃ composite. Crystallite size decreased from ~46 nm (100B) to ~25 nm (3F), varying with La between 33 and 25 nm. SEM/TEM revealed a reflection in morphology and size with composition from disk-like particles to petal-like spherical aggregates. Antimicrobial screening revealed composition-dependent inhibition: against S. aureus, 20L was the most potent (~94%). Overall, La/Fe tuning under a plant extract-assisted microwave–hydrothermal route enabled phase- and morphology-controlled Bi₂O₃-based nanocomposites with enhanced antimicrobial activity, with ultrafine, high-surface-area architectures emerging as promising antibacterial candidates. Full article

Background/Objectives: Natural macromolecule-based drug delivery carriers have gained extensive attention for biomedical applications. This study aimed to construct an efficient oral delivery system for the widely used antitumor drug docetaxel (DTX) by utilizing natural nanoparticles derived from Ganoderma (LZ-Nnps). Methods: LZ-Nnps loaded with DTX (LZ-Nnps-DTX) were fabricated via an optimized heat-induced self-assembly approach and characterized for morphology, particle size, zeta potential, stability, drug loading, encapsulation efficiency, and molecular interactions with DTX. Intestinal absorption, pharmacokinetics, and tissue distribution were respectively assessed, while antitumor efficacy, macrophage internalization mechanisms, and immunomodulatory activation were further investigated. Results: The optimized formulation showed a particle size of 361.3 ± 5.3 nm, zeta potential of −39.55 ± 1.31 mV, drug loading of 1.51 ± 0.08%, and near-complete encapsulation efficiency (99.97 ± 0.02%), with favorable stability in gastrointestinal fluids. Hydrogen bonding and hydrophobic interactions effectively kept DTX in a stable amorphous state. LZ-Nnps-DTX markedly improved DTX aqueous solubility, dissolution, and intestinal absorption. In vivo assays showed oral LZ-Nnps-DTX achieved 34-fold higher C_max and 7.8-fold larger plasma AUC_0-t than free DTX, and mainly accumulated in the liver and lung. The nanoparticles entered Caco-2 cells via macropinocytosis and mainly accumulated in the liver. LZ-Nnps-DTX exerted strong cytotoxicity against HepG2, A549, and HCT116 cells, was internalized by RAW264.7 macrophages through caveolae-mediated endocytosis and phagocytosis, and stimulated TNF-α and NO production to suppress tumor growth. Conclusions: These findings demonstrate that LZ-Nnps-DTX effectively enhances oral bioavailability, exerts potent antitumor effects, and activates macrophage-mediated immunity, supporting its promise as an oral DTX delivery system. Full article

This study aimed to investigate the repair performance of these materials subjected to different surface treatment protocols using combined mechanical and optical evaluations. Four resin-matrix materials were evaluated: two CAD/CAM materials (HIPC Plus and GC Cerasmart) and two additively manufactured resins (VarseoSmile TriniQ and CrownTec). Standardized disc specimens were fabricated and thermocycled prior to repair. Three surface treatments were applied: airborne particle abrasion (APA), tribochemical silica coating (TSC) with silane, and laser treatment (LT). Micro-shear bond strength (µSBS) was measured using composite cylinders bonded to treated surfaces. For optical evaluation, standardized cavities were restored with composite resin, and color measurements were obtained at baseline (T0) and after aging (T1) using a spectrophotometer. Color mismatch and color stability were calculated. Data were analyzed using two-way ANOVA and Tukey tests (α = 0.05). Material type and surface treatment significantly affected µSBS (p < 0.001). CAD/CAM materials had higher bond strength than additively manufactured ones. The TSC group showed the highest µSBS. Aging increased color mismatch, with post-aging ΔE00 values surpassing clinical thresholds. Additively manufactured materials experienced greater color changes. Repair performance depends on manufacturing method and surface treatment. The higher bond strength in the TSC group likely results from silica coating and silanization. CAD/CAM materials showed better optical stability. Full article