Search Results (20,700)

Hydrogen is frequently incorporated in alkaline-earth oxides during crystal growth or post-deposition annealing. For MgO, several studies in the past showed that interstitial monatomic hydrogen can also favourably bind with oxygen vacancies to form stable substitutional defect complexes (substitutional hydrogen or U-defect centers). The present study reports first-principles density-functional calculations of the formation energies of both interstitial and substitutional forms of the hydrogen impurity in MgO. Determination of the site-resolved densities of electronic states allowed for a detailed identification of the nature of the impurity-induced levels, both in the valence-energy region and inside the band gap of the host. The stability and diffusion mechanisms of both hydrogen defects was also studied with the aid of nudged elastic-band (NEB) calculations. Interstitial hydrogen was found to be an amphoteric defect with the lower formation energy for any realistic environment conditions (temperature and oxygen partial pressure). The NEB calculations showed that it is a fast-diffusing species when it is thermodynamically stable as a positively-charged state (bare proton). In contrast, the hydrogen-vacancy complex is a shallow donor, extremely stable against dissociation and virtually immobile as an isolated defect. Its formation is found to be favoured for a range of mid-gap Fermi-level positions where positively-charged interstitial hydrogen and neutral oxygen vacancies (F centers) are both thermodynamically stable low-energy defects. The present findings are consistent with the established consensus on the electrical activity of hydrogen in MgO as well as with experimental observations reporting the remarkable thermal stability of substitutional hydrogen defects and their ability to act as electron traps. Full article

Cholinergic dysfunction is a hallmark of Alzheimer’s disease (AD), driven by elevated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity that depletes acetylcholine and contributes to amyloid pathology. Current AD treatments face major challenges, including poor brain penetration, short effect duration and safety concerns, highlighting the need for compounds suitable for preventive or earlier-stage intervention. This study investigated marine phytohormones as modulators of cholinergic imbalance, using an integrative strategy encompassing enzymatic assays, QSAR and DFT calculations, molecular docking, molecular dynamics (MD) simulations, and ADMET profiling. Among them, isopentenyl adenine (IPA) and abscisic acid (ABA) showed inhibitory activity against cholinesterases. IPA inhibited both AChE and BChE through distinct mechanisms with noncompetitive inhibition of AChE and competitive inhibition of BChE, while ABA showed selective noncompetitive inhibition of AChE. DFT-based analysis revealed distinct electronic properties supporting differential reactivity. Moreover, IPA interacted with both catalytic and peripheral residues in AChE, and aligned with BChE’s active site, while ABA was bound more peripherally. MD simulations confirmed complex-specific conformational stability based on RMSD, RMSF, Rg, and hydrogen bonding analysis. Both compounds showed low off-target potential against serine proteases and favorable predicted ADMET profiles. These results support the potential of marine phytohormones as preventive modulators of cholinergic dysfunction in AD. Full article

An alkali-activated slag binder based on biochar was developed in this research. The biochar was produced from waste wood and is referred to as biochar waste (BW). In the alkali-activated slag system, a small amount of biochar (up to 0.5%) was used as an additive, and a larger amount (from 1% to 25%) was used as a filler. The influence of the biochar powder on compressive strength was determined. The hydrated samples were investigated using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM), and the thermal, acoustical properties, and hydration temperature were also determined. The compressive strength of the alkali-activated slag composite, especially after 7 days, was found to increase slightly due to the introduction of a small amount (0.05–0.5%) of BW powder. The powder in the alkali-activated slag matrix was distributed homogenously, resulting in a reduction in the crack propagation. A larger amount of BW led to a non-homogeneous distribution, and this resulted in a gradual reduction in compressive strength with increasing BW. The highest values of compressive strength at 28 days of hydration (44.4 MPa) were recorded for samples with 0.25% of BW. According to mathematical analysis methods, the compressive strength is mainly influenced by the specific surface area of the initial mix ingredients and the amount of BW additive. In the alkali-activated slag matrix, BW acted as an inert micro-filler, with the dilution effect possibly being the reason for the decrease in the hydration temperature. SEM analysis demonstrated that the BW had a good adhesion with the alkali-activated slag matrix. The thermal and acoustic insulation performance of samples with BW improved. These investigations suggest that BW can be successfully incorporated in alkali-activated material, resulting in low thermal conductivity and adequate acoustic insulation performance. Full article

In the medical industry, strong disinfectants are used to limit bacterial proliferation on the surface of polymer-based materials; however, they may leave hazardous residues. To prevent potential harm to human health, safer disinfection substitutes are continuously searched. This study evaluates the effect of a natural biocidal modifier, geraniol (GR), on the properties of flax-reinforced biocomposites. Biocomposites containing 80 wt% polylactide (PLA) and 20 wt% flax fibres were prepared, and fibres were modified with 1%, 5%, 10%, or 20% GR. The materials were examined using tensile tests, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetry (TG), contact angle measurements, scanning electron microscopy (SEM), and antibacterial activity tests. The incorporation of flax fibres increased the storage modulus from 2730 MPa (PLA) to 3447 MPa, while GR-modified fibres further enhanced stiffness up to 3769 MPa for the 20% GR sample. Strong antibacterial activity against Escherichia coli and Staphylococcus aureus was achieved in biocomposites containing ≥10% GR, with R = 5 and R ≥ 6, respectively. Surface hydrophobicity also improved progressively, and a water contact angle of 92° was obtained at 20% GR. These results demonstrate that geraniol-modified flax fibres effectively impart antibacterial activity and hydrophobicity to PLA biocomposites, indicating their potential for use in sustainable packaging applications and materials for the medical sector. Full article

To address the lack of inertia in full-power converter wind turbines and the inability of existing mechanical speed regulation technologies to achieve power smoothing without converters, this paper proposes a novel hybrid wind energy storage system integrating a Continuously Variable Transmission (CVT) and an electromechanical flywheel. This system establishes a cascaded topology featuring “CVT-based source-side speed regulation and electromechanical flywheel-based terminal power stabilization.” By utilizing the CVT for speed decoupling and introducing the flywheel via a planetary differential branch, the system retains physical inertia by eliminating large-capacity converters and overcomes the bottleneck of traditional mechanical transmissions, which struggle to balance constant frequency with stable power output. Simulation results demonstrate that the proposed system reduces the active power fluctuation range by 47.60% compared to the raw wind power capture. Moreover, the required capacity of the auxiliary motor is only about 15% of the rated power, reducing the reliance on power electronic converters by approximately 85% compared to full-power converter systems. Furthermore, during a grid voltage dip of 0.6 p.u., the system restricts rotor speed fluctuations to within 0.5%, significantly enhancing Low Voltage Ride-Through (LVRT) capability. Full article

This work examines resistance drift in FPGA I/O paths subjected to combined electrical and thermal stress, using a Xilinx Spartan-6 device as a representative platform. A multiplexed measurement approach was employed, in which multiple I/O pins were externally shorted and sequentially activated, enabling precise tracking of voltage, current, and effective series resistance over time, under controlled bias conditions. Two accelerated stress modes were investigated: high-temperature dwell in the range of 80–120 °C and thermal cycling between 80 and 140 °C. Both stress modes exhibited similar sub-linear (power-law) time dependence on resistance change, indicating cumulative degradation behavior. However, Arrhenius analysis revealed a strong contrast in effective activation energy: approximately 0.62 eV for high-temperature dwell and approximately 1.3 eV for thermal cycling. This divergence indicates that distinct physical mechanisms dominate under each stress regime. The lower activation energy is consistent with electrically and thermally driven on-die degradation within the FPGA I/O macro, including bias-related aging of output drivers and pad-level structures. In contrast, the higher activation energy observed under thermal cycling is characteristic of diffusion- and creep-dominated thermo-mechanical damage in package-level interconnects, such as solder joints. These findings demonstrate that resistance-based monitoring of FPGA I/O paths can discriminate between device-dominated and package-dominated aging mechanisms, providing a practical foundation for reliability assessment and self-monitoring methodologies in complex electronic systems. Full article

Directed Energy Deposition-Laser (DED-L) enables high-performance coatings through melting and successive powder deposition. Its compositional flexibility suits functionally graded layers that enhance corrosion and wear resistance. This study aimed to improve parameters for producing dense, defect-free, graded Ni- and Fe-based coatings by varying the scanning speed and deposition strategy (monodirectional versus bidirectional, with/without layer rotation), while keeping the power and hatch distance constant. Laser and electron microscopy were used to link parameters to porosity and uniformity. Optimal settings minimized pores, improved interlayer bonding and preserved geometry; inadequate parameters yielded porous, irregular deposits. A bidirectional path with 90° rotation appeared best. Ongoing research activities are needed to assess its properties. Full article

Black spot disease substantially impairs both the aesthetic quality and commercial viability of affected Pingguoli pears. Previous studies have shown that Alternaria alternata and A. tenuissima are the pathogens that cause black spot disease. Essential oils represent novel alternatives to synthetic fungicides to control these pathogens. This study extracted Artemisia sieversiana essential oil (AsEO) by hydro-distillation using a crystal tower pure dew essential oil machine. The chemical compositions of AsEO were analyzed via gas chromatography–mass spectrometry (GC–MS). A total of 42 compounds were detected. 1,8-cineole, trans-caryophyllene, (1R,4S)-1,7,7-trimethylbicyclo [2.2.1] heptan-2-yl acetate, (±)-camphor, and β-myrcene were identified as the five main constituents. Moreover, the antifungal activity of AsEO was assessed against black spot on Yanbian Pingguoli pear in China. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were determined as 0.10% (v/v) and 0.12% (v/v), respectively. Scanning electron microscopy (SEM) analysis revealed that treatment with AsEO induced significant morphological aberrations in A. alternata and A. tenuissima mycelia, including surface roughening, hyphal collapse, and loss of structural integrity. Concurrently, a marked increase in alkaline phosphatase (AKP) enzyme activity and electrical conductivity was observed, a key indicator of cell wall and plasma membrane permeabilization and damage. When the concentration of AsEO was less than 120 µg/mL, there was no toxicity to keratinocytes (HaCaTs) and skin fibroblasts (NHSFs). In summary, this study provides a theoretical basis for the development of AsEO as a fungicide against black spot disease on Pingguoli pear in China. Full article

Although carbon filters (CF) can exhibit limited adsorption/selectivity for certain emerging pollutants and operating conditions, incorporating carbon–metal-oxide composites provides a platform to study how surface chemistry, charge distribution and oxide dispersion influence adsorption behavior. This study investigates the incorporation of metal oxides (Fe₃O₄, TiO₂ and CaO) into a commercial carbon filter via mechanical milling, focusing on fundamental changes in surface properties and methylene blue (MB) adsorption mechanisms. The synthesized oxides were characterized by X-ray diffraction and scanning electron microscopy, confirming crystalline structures with crystalline sizes between 11 and 23 nm. Composite filters with varying oxide contents (10–30 wt%) were evaluated for point of zero charge (PZC), surface charge distribution and methylene blue (MB) adsorption. The kinetic experiments were adjusted to pseudo-second order (PSO). Although the maximum adsorption capacity (2.75 mg·g⁻¹ for CaO-modified filters) is lower than commercially activated carbons, this work clarifies how oxide type and dispersion control adsorption performance and interaction mechanisms. Langmuir and Freundlich models revealed monolayer adsorption with favorable dye-surface interactions. These models provide key insights into the role of oxide type and pH in the dye removal process. Full article

Stropharia rugosoannulata is a widely cultivated edible mushroom known for its nutritional value and umami flavour. Electronic tongue technology and metabolomics revealed that glutamic acid (Glu) and aspartic acid (Asp) levels were positively correlated with umami in the fruiting body developmental stages. Subsequent investigations found that overexpression of SrCS within the TCA cycle resulted in decreased levels of Glu and Asp. Integrating TF-gene-metabolite network modelling with experiments identified SrELT1 as a transcriptional regulator of SrCS. Different temperatures, cultivation substrates and genetics significantly impacted SrELT1 and SrCS expression, thereby affecting Glu and Asp synthesis. The findings suggest that increased Citrate synthase (CS) activity channelled citrate into glycolysis and oxidative phosphorylation without excessive accumulation; in contrast, decreased CS activity shifted metabolism toward the production of metabolites like Glu and Asp. This study provides insights for enhancing the umami of S. rugosoannulata, thereby substantially increasing its market competitiveness in the premium food segment. Full article

Efficient conversion of biomass-based platform molecules into high-value derivatives is recognized as one formidable challenge in biomass upgrading. In this work, a one-pot deep eutectic solvents-assisted solvothermal method was developed for the modification of the commercial Pt/C catalysts by introducing a secondary metal (M = Sn, Bi, Ge, Sb, Pb). The structural and electronic properties of the catalysts were precisely tuned. Among the screened metals, the addition of Sn yielded the most significant improvement in catalytic activity. The optimized PtSn_0.5/C-140 catalyst achieved superior furfural (FAL) conversion and furfuryl alcohol (FOL) selectivity under mild conditions (20 °C, 2 MPa H₂). Comprehensive characterizations, including XRD, HRTEM, XPS, and H₂-TPD, confirmed the formation of Pt-Sn solid-solution phase. Furthermore, Characterization and reaction results revealed that the electronic and geometric effects induced by Sn modulated Pt active sites, significantly enhancing the adsorption of the active H species. Additionally, the SnO_x species adjacent to the Pt-Sn sites served as hydrogen spillover acceptors, further accelerating the hydrogenation process. The synergy between the Pt-Sn solid-solution phase and SnO_x species is identified as the origin of the superior performance at room temperature. These findings provide a new strategy for the design of high-performance biomass conversion catalysts by upgrading commercial noble metal catalysts. Full article

Innovations are the driving force of change and are essential even in traditional activities such as regional food production. This is especially important considering that locally produced food can be a healthier, more organic, and sustainable alternative to mass-produced food. In this context, the research aims to identify the characteristics of innovative producers and their implications for creating effective policies in the rural regional food sector in Poland. A survey research study using an electronic questionnaire was conducted among a group of 400 regional food producers in Poland in July 2024. Differences between the groups analyzed of regional food producers were examined using a series of non-parametric tests. The results indicate that innovative regional food producers differ significantly from non-innovative producers in many aspects. In terms of raw materials, finance, knowledge, and skills, the differences concern the greater reliance on external resources, as well as a weaker connection with family knowledge and skills, compared to non-innovative producers. The contribution of the research includes the identification of conditions that facilitate the innovativeness of regional food producers, as well as the features that enable or hinder this process. The dissemination of innovations among regional food producers in Poland requires financial and non-financial support. Support for innovation is a crucial component of an effective rural development policy in Poland. Full article

Bacterial spores, as one of the most resistant microbial forms, are difficult to completely eliminate through conventional heat treatments such as pasteurization, allowing them to persist in food and pose a significant threat to microbial safety. This study employed a “germination–inactivation” strategy to inactivate Alicyclobacillus acidoterrestris (AAT) spores using a germinant under low-intensity pulsed electric fields (PEFs). Analysis of germination curves identified 40 mM L-valine as the most effective germinant. Results showed that after 4-h incubation with 40 mM L-valine followed by 210 s of 0.18 kV/cm PEF treatment, the synergistic effect of electric field and ohmic heating (OH) reduced AAT spore counts by 1.73 log units. In contrast, the control group treated with the same PEF parameters without a germinant showed only a 0.54 log unit reduction. These findings indicate that germination agents significantly reduce spore resistance. Subsequent experiments confirmed that L-valine-treated AAT spores underwent pronounced structural disruption under the combined effects of the electric field and OH, leading to leakage of intracellular components such as nucleic acids and proteins. This phenomenon was verified via scanning electron microscopy (SEM) and laser confocal microscopy. Additionally, both ROS levels and ATPase activity in spores were substantially reduced, further indicating that the combined electric field and OH synergistically disrupted the spore’s external structure and internal macromolecules, leading to spore death. Thus, low-intensity PEF assisted by spore germination agents offers an energy-efficient and effective inactivation method, opening new avenues for spore inactivation research. Full article

Cadmium sulfide is an important II-VI semiconductor known for its valuable photocatalytic properties ascribable to its band gap energy, which allows light absorption in the visible domain. Nonetheless, the application of cadmium sulfide in wastewater organic pollutant degradation is restricted due to its high toxicity to humans, soil, and marine life. To address this issue, we developed new composite materials by depositing CdS on a bentonite support in a 1:9 mass ratio to develop a photocatalyst with lower toxicity. In the first step, bentonite was activated using an aqueous HCl solution; for the deposition of CdS powder, we proposed the trituration method and compared it with chemical precipitation and hydrothermal synthesis, using thioacetamide as a sulfide ion source. The modified bentonite underwent characterization using X-ray diffraction, scanning electron microscopy, X-ray fluorescence, UV-Vis, and FTIR spectroscopy. The photocatalytic activity was tested in the degradation of Congo red (CR), a persistent diazo dye. The efficiency of removing CR with CdS–bentonite composites depended on the deposition method of CdS, and it was higher than that of pristine CdS and of only adsorption onto acid-activated bentonite. The photocatalytic degradation mechanism was estimated by the scavenger test using ethylenediaminetetraacetic acid disodium salt, ascorbic acid, ethanol, and silver nitrate as radical scavengers. Full article

Metalloporphyrin-based covalent organic frameworks (MPor-COFs) are emerging porous crystalline materials that combine the optoelectronic properties of metalloporphyrins with the highly ordered structure of COFs. Such a combination not only extends the light absorption spectrum of COFs by incorporating porphyrins but also improves the separation and transport capabilities of photo-generated electrons and holes by leveraging the structural advantages of organic frameworks. At the same time, the metal ions embedded in the porphyrin ring provide abundant active sites and optimize charge transfer channels, showing particular advantages in photocatalysis. The molecular design, construction, and photocatalytic application of MPor-COFs were reviewed in this paper. The intrinsic relationship among the structure, optoelectronic properties, and specific photocatalytic application received special attention. First, the role of the metal center in regulating the electronic structure and photophysical property of porphyrin monomers was introduced, as well as the impact of bond type on framework stability and charge transport efficiency. Then, the synthesis strategies for MPor-COFs were summarized. Finally, the applications of these materials in photocatalysis were critically reviewed, and their prospects and challenges in energy conversion and environmental remediation were also discussed. Full article