University of Miskolc

Magnetic iron oxide nanoparticles are frequently utilized as contrast agents in magnetic resonance imaging (MRI). However, the release of iron ions leads to the formation of reactive oxygen species (ROS), resulting in cell damage. In this study, we developed MRI contrast agents containing amine-functionalized MnFe2O4 nanoparticles with a Prussian blue (PB) surface coating to enhance their biocompatibility. The prepared MNPs were embedded in polyvinylpyrrolidone and dried. The resulting crystals can be redispersed in water immediately before use, forming a stable colloid. The particle size of nanoparticles (43 ± 13 nm) is suitable for the intended application. The values of Hc (52 Oe) and Mr (3.7 emu/g) for the particles indicate a soft ferromagnetic nature. The coating of the particles with PB results in a significant reduction of their toxicity, as evidenced by a toxicological test on HEK293 cells. This colloid was tested in vitro as an MRI contrast agent as well as in healthy animal. The longitudinal relaxivity (r1) of the PB-MnFe2O4-NH2 sample was determined to be 0.01 (mg/mL)⁻¹ms− 1. The transversal relaxivity was measured as well (r2: 0.77 (mg/mL)⁻¹ms− 1 and r2*: 1.48 (mg/mL)⁻¹ms− 1, which were in the same range as Feraheme and Endorem. Prussian blue-coated MnFe2O4 emerges as a promising T2-weighted contrast material, representing a novel combination of two well-known contrast-capable materials.

The in-plane tensile-compressive test is a key method for studying plastic behavior under complex loading. This study presents a novel anti-buckling fixture designed for cyclic testing. The device can conduct monotonic tensile-compressive tests with deformations of up to 10%. The specimen is encased in an acrylic block for structural stability and to prevent buckling. Its application and impact on the force-displacement curve have been addressed. The AutoGrid optical strain measurement system was integrated with the fixture for strain analysis, and its accuracy was systematically evaluated. The developed fixture is well-suited for accurately describing the plastic behavior of materials under complex loading paths and it aids in precisely determining the kinematic hardening characteristics.

In this study, pristine TiO2 and Copper (Cu)-doped TiO2 nanopowders were synthesized using two sol-gel methods: conventional sol-gel (SG) and microwave-assisted sol-gel (MW). The aim was to investigate the effect of the synthesis route and Cu doping on the structural, optical, and photocatalytic properties of TiO2. X-ray diffraction (XRD) analysis confirmed the formation of anatase TiO2 in all samples, with a minor presence of rutile observed in the samples obtained by the MW method. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray analysis (EDX) showed that the nanopowders obtained by the MW method exhibited a greater tendency for particle aggregation compared to those obtained through the SG method. The presence of Cu²⁺/Cu⁺ species in the samples was confirmed by X-ray photoelectron spectroscopy (XPS). UV-Vis reflectance measurements revealed a shift in the absorption edge of the 5% Cu-doped samples toward the visible light range, significantly reducing the band gap. Evaluation of photocatalytic activity demonstrated that doping TiO2 with 5% Cu enhanced the degradation of Congo Red dye under visible light. Graphical Abstract

Today's supply chains are facing serious challenges. The ever-changing environment, economic situation, and differentiating customer needs make it difficult for chains to operate. To produce a product or service that meets customer needs, it is necessary to work with the right partners. But this is not enough. A dynamic and changing environment also requires flexibility and adaptability, not just for one company but for the whole chain. This is resilience. This study aims to examine which factors determine the choice of supplier in a supplier-customer partnership and how flexible these factors are. The research was carried out using an online questionnaire among Hungarian enterprises.

The present study uses three mathematical approaches to analyze the dual-purpose solar collector, making it a novel contribution. Three MATLAB codes (C1, C2, and C3), each with its mathematical model, are developed. The effectiveness- number of transfer unit method is used in C1. The heat removal term is used in C2. In C3, the effectiveness term of the parallel flow heat exchanger is used. Mathematical modeling, simulation, and experimental validation are conducted for each code. The calculated numerical-experimental errors revealed excellent convergence. The root mean square error and the mean absolute error for C3 are 1.8 and 1.5, respectively, which are less than for C2 and C3. This indicates that C3 is a reliable approach and can assist researchers in future analysis of the dual-purpose solar collector.

Photoremovable protecting groups (PPGs) offer a straightforward solution for the temporary inactivation of biologically active substrates and their subsequent controlled release by light irradiation. Their relatively easy design and mode of application have made them useful tools for studying dynamic biological processes in vitro and in vivo. Recently, there has been a growing body of data investigating their potential application in the development of drug delivery systems. Of the various PPG scaffolds in use, quinoline photocages have a history of about 20 years. The structure‐property relationships of quinoline PPGs, as well as alternative multibranch designs based on quinoline monomers have been thoroughly studied both experimentally and theoretically. Therefore, quinoline PPGs serve as a representative study of PPG development, showing how the various applications of quinoline photocages followed the chemical optimization or how the applications drove the chemical design. Since the raison d’être of PPGs lies in their application for light‐activated release of various substrates or performing light‐activated structural changes in materials, it is crucial to understand how PPGs are selected and utilized by their end‐users, who are often not chemists themselves. Therefore, we discuss whether the conclusions drawn from the selected quinoline PPG family could lead to more general insights for the field as whole. As PPG‐related applications still rely heavily on a limited number of chemical scaffolds, it is worth considering, what could be the reasons for the slow uptake of novel chemical scaffolds.

Natural rutile is a widely available titanium mineral which shows great potential as a photocatalyst for environmental remediation when processed correctly. Industries invest large sums in the transformation of the rutile mineral into pure, synthetic nano titania. Still, the present study proves that bare natural rutile with trace element content can also be applied as a photocatalyst, without harsh chemical interventions, simply by processing via nano grinding. Samples with different mean primary particle size values were obtained by wet stirred media milling, their compositional and structural properties were investigated, and their photocatalytic properties were evaluated under both visible- and UV-light illumination for the degradation of phenol and ibuprofen. By changing the grain size and the particle size distribution, and due to the doping effect of impurities present in the mineral, the band gap values of the samples and their photocatalytic activities changed as well. The nano milled rutile exhibited visible light photocatalytic activity, with a 33% degradation efficiency in the case of both phenol and ibuprofen, after 22 h of irradiation. The present study not only highlights the photocatalytic degradation of a pharmaceutical by natural rutile mineral, but its findings also suggest that ground nano rutile can function as an environmentally friendly photocatalyst, as it not only avoids the use of harmful chemicals typically employed in TiO2 synthesis but also offers a simpler, more cost-effective alternative for producing photocatalytic materials.

Optimizing feeding rates in recirculating aquaculture systems (RAS) is crucial for ensuring fish growth, health, and system efficiency. This research introduces a novel approach to RAS feeding control using a Deep Deterministic Policy Gradient (DDPG) reinforcement learning algorithm. The developed system integrates feeding rate optimization with comprehensive water quality management to improve overall performance and stability. The DDPG controller demonstrated superior tracking accuracy, reduced feed consumption, and improved operational stability compared to traditional control methods such as Model Predictive Control (MPC), PID, and Bang-Bang control. The learned policy-maintained feeding rates within optimal ranges while adapting to dynamic system requirements and environmental conditions. The integration of water quality monitoring and control further enhanced system stability, ensuring critical parameters remained within target ranges. Comparative analysis revealed the DDPG controller’s advantages in terms of faster recovery times after environmental perturbations, improved long-term stability, and significant economic benefits through reduced operational costs and increased efficiency. The robustness and adaptability of the system were validated through comprehensive testing under various fault conditions, growth phases, and system scales. The successful development and evaluation of the DDPG-based RAS feeding control system represents a significant advancement in aquaculture management. The demonstrated improvements in efficiency, stability, and economic performance establish the potential for this approach to revolutionize feeding practices in commercial RAS operations. Further research and development efforts can build upon these findings to advance the state-of-the-art in intelligent aquaculture management systems and promote the sustainability and profitability of the industry.

Biomass torrefaction is a thermochemical process that transforms biomass into a more energy-dense fuel, producing solid biochar, volatile organic compounds, and gases such as carbon dioxide (CO₂), carbon monoxide (CO), and nitrogen oxides (NOx). In this study, the effects of solar drying, as a sustainable preprocessing method, and subsequent torrefaction were evaluated under varying initial moisture content levels of 5%, 10%, 15%, and 20%. The drying conditions of wood chips and the torrefaction process were documented for a sustainable biomass drying system using solar energy. Comprehensive proximate and final analysis and flue gas monitoring analyzed the torrefied biomass’s emission characteristics and combustion efficiency. Results showed that higher initial moisture content increased hydrogen and volatile matter, decreased fixed carbon, and marginally raised the higher heating value. This study shows that solar drying optimizes biomass pretreatment and is a cost-effective and environmentally friendly alternative to conventional drying. This work sheds light on the relationship between initial moisture content, emission characteristics, and combustion behavior, aiding bioenergy development.

A naturally derived silicate, diatomaceous earth has been endowed with magnetic properties by depositing magnetite nanoparticles on its surface. Palladium crystallites were created on the resulting magnetizable catalyst support. The support provided high specific surface area with high porosity which were ideal for the binding of both the magnetic particles and the palladium. The catalyst was successfully tested in the hydrogenation of benzophenone in three different solvents (methanol, ethanol, and isopropanol). Significant differences in catalytic activity were observed, allowing selective production of benzhydrol (BH) or diphenylmethane (DPM) by a simple solvent change. Beside the excellent selectivity, the featured catalyst also provided an easy and fast method for catalyst recoverability using a simple magnet.

The increasing demand for high-frequency applications and the widespread use of electromagnetic (EM) waves in communication systems necessitate the development of effective electromagnetic interference (EMI) shielding materials. This study investigates the structural and shielding effectiveness properties of novel polyaniline (PANI)-based NiO/ZnNb2O6 composites for sub-8 GHz applications. NiO and ZnNb2O6 were synthesized via conventional solid-state reactions and combined with PANI to form composites with varying compositions. X-ray diffraction (XRD) confirmed the successful formation of single-phase NiO and ZnNb2O6, while scanning electron microscopy (SEM) revealed well-defined microstructures, contributing to enhanced shielding efficiency. Shielding effectiveness (SE) measurements were performed across the 0–8 GHz frequency range using a vector network analyzer. Among the compositions tested, the epoxy-based NiO-ZnNb2O6 (75–25% by weight) with a 1:1 PANI ratio exhibited the highest SE value of −41.16 dB (decibels) at 6.24 GHz, demonstrating superior attenuation of EM waves. The observed shielding efficiency is attributed to multiple reflection effects, dipole interactions, and the conductive network formed by PANI. These findings highlight the potential of NiO/PANI/ZnNb2O6 composites as cost-effective, high-performance EMI shielding materials for next-generation microwave communication and electronic applications. Further optimization and hybridization approaches are recommended to enhance performance for broader frequency bands.

Introduction: Oral hygiene and the development of good health habits play an important role in maintaining overall health and achieving a good quality of life, thereby influencing self-confidence and psychological and somatic well-being. The aim of our research was to draw attention to the poor oral hygiene indicators of marginalised and disadvantaged groups and to look for correlations between different health behaviours and lifestyles. Methods and data: Our research covered the prevalence of dental caries (decayed, missing, and filled teeth [DMFT] value), their dental visits and brushing habits, their lifestyle, psychosomatic state, and self-evaluation. Results: Sample characteristics: n = 429 (318 primary school students + 111 high school students), mean age 11.5 (SD:3.2) years. One-third of the students lived in overcrowded, uncomfortable homes, 33.3% of which had no piped water supply. Nearly 40% of students reported that there was a dentist in their village, but 73% only visited a dentist when they had a toothache. Nearly half of students brush their teeth every morning and evening, but only a third receive more than 1 toothbrush a year. Many do not even have a toothbrush or only get one if their family can afford it. More than two-thirds of students consume sugary drinks and snacks after brushing their teeth in the evening. A high percentage (51.6%) were found to have acute gingivitis, and 47.8% of students were diagnosed with chronic gingivi-tis. The DMFT value was high at 6 (SD: 3.2), with a significant positive correlation between these values and post-toothbrush evening meals (p < .019). A total of 24% of the study group consumed alcohol regularly, and there was a high prevalence of smoking. The DMFT index showed a significant correlation (P < .036) with alcohol consumption. Conclusion: The cumulatively disadvantaged youngsters' oral hygiene and health behavioural habits show serious arrears, where unmotivated family background, low income, lack of dental education, and unavailable health care/preventive services all play an important role. Ó 2025 The Authors. Published by Elsevier Inc. on behalf of FDI World Dental Federation. This is an open access article under the CC BY license

Groundwater is a critical resource for sustaining human activities, particularly in urban areas, where its importance is exaggerated by growing water demands, urban expansion, and industrial activities. Ensuring future water security necessitates an in-depth understanding of groundwater recharge dynamics, which are often complex and influenced by rapid urbanization. The alarming decline in groundwater resources in both urban and rural regions underscore the urgency for advanced groundwater management strategies. However, identifying and evaluating groundwater recharge potential zones (GWPZs) remains a challenge due to the dynamic interplay of hydrogeological and urban development factors. This study employs an integrated approach combining geographic information system (GIS), remote sensing, and multi-criteria decision analysis using the analytical hierarchy process (MCDA-AHP) to delineate GWPZs in the Sulaymaniyah Basin (SB). The methodology is further supported by hydrogeological data and validated through geophysical investigation using electrical resistivity tomography (ERT) data. For the MCDA-AHP, six thematic layers including rainfall, geology, lineament density, slope, drainage density, and land use/land cover were derived from satellite imagery, geological surveys, and well data. These layers were ranked based on their relative influence on groundwater recharge and integrated using GIS-based weighted overlay analysis to generate groundwater potential maps. The results identified three potential zones for groundwater recharge: low (11.26%), moderate (45.51%), and high (43.23%). Validation using ERT data and receiver operating characteristics (ROC) analysis revealed strong agreement, with an area under the curve (AUC) accuracy of 86%. These findings demonstrate the robustness of the integrated approach, providing a reliable tool for minimizing hydrogeophysical exploration costs and reducing the number of unsuccessful boreholes.

Lake Nasser in Egypt contains significant tilapia fish quantities, yet consumption remains low due to its geographical isolation from marketing and consuming areas. Therefore, investigating efficient and economical Tilapia fish drying methods is essential. The current study developed and tested a solar dryer based on solar energy collection, using evacuated tubes at three Nile Tilapia slice (NTS) thicknesses of 4, 8, and 12 mm, and an air velocity of 0.5 m/s. The obtained result of the solar dryer with evacuated tubes (SDET) was compared with the other results of the oven liquid petroleum gas (OLPG) as an industrial drying method. The results obtained showed that the air temperature inside the drying room of the SDET ranged between 44 and 75 °C. The average initial moisture content (MC) was 74.83% (w.b.). For both systems, the drying time ranged between 13 and 17 h at the same slice thickness. The effective moisture diffusivity was in the range of 0.87 × 10–11 to 5.66 × 10–11 m²/s. Furthermore, the mathematical modeling revealed the Modified Midilli (II) and Modified Henderson and Pabis models as the most suitable models to describe the drying behavior of NTS dried on SDET. On the other hand, the environmental analysis indicates that the developed SDET can mitigate approximately 273.6 tons of CO2 during its lifetime, resulting in a carbon credit equivalent of approximately 19,838.89 $. Additionally, the economic analysis of the SDET showed that the annual production of dried fish was 450 kg; this may result in substantial cost savings, amounting to a total of 608.4$ per year. Also, the developed SDET had a payback period of approximately 0.413 years or less than half a year.

A novel method is presented for the determination of the thermodynamic behavior and classification of quaternary mixtures. Since the quaternary mixtures are formed by four ternary sub‐mixtures, the systematic investigation takes place first in two‐dimensional and then in three‐dimensional tetrahedrons, presenting the residue curve map with a binodal plot. The mixtures can be classified into four groups, and six rules can be concluded for the change in the type of the nodes and saddles, if a new compound appears. The rules help understand the thermodynamic behavior and complete the engineering design of alternatives. The procedure is demonstrated experimentally on the separation problem of a quaternary mixture based on extractive heteroazeotropic distillation (EHAD).

Highlights Eco-friendly geopolymer foams are developed from silica fume, natural zeolite, and H2O2. The addition of a stabilizer produces smaller and more homogeneous pore sizes. The technical properties highly depend on porosity and pore size distribution. The samples produced showed good compressive strength and low thermal conductivity. These foams could be a sustainable substitute for thermal insulation. Abstract The need for environmentally friendly and energy-efficient building materials has increased significantly. This study synthesizes geopolymer foams with enhanced thermal insulation properties using silica fume and natural zeolite tuff. Zeolite’s porous structure and active sites improve polymerization and strengthen the foam, while silica fume reacts with NaOH to release sodium silicate, forming a durable geopolymer matrix. Foam porosity is introduced by generating oxygen gas from H2O2 and NaOH, with calcium stearate stabilizing the foam structure. Comparative analysis of the compressive strength, bulk density, porosity, and thermal conductivity shows that incorporating H2O2 and calcium stearate significantly reduces thermal conductivity (from 0.19 to 0.06 W/m·K) while ensuring a highly porous system (66–82.6% porosity) with adequate mechanical strength (1.6–3.39 MPa). These findings highlight the potential of the developed geopolymer foam for sustainable insulation applications.

Seventy-seven groundwater samples from Wadi Ranyah, Saudi Arabia, were analyzed to assess their physical and chemical properties. Initially, the physiochemical parameters were compared to the World Health Organization (WHO) standards and studied with Durov and Chadha diagrams. Multivariate statistical indices, such as the saturation index (SI), chloro-alkaline indices (CAI), Gibbs ratios, heavy metals pollution and evaluation indices (HPI and HEI), and the hierarchical cluster analysis (HCA), were used to identify the sources of water pollution. Durov’s diagram showed that Ca and HCO 3 ions were the dominant, and forward ion exchange was the main hydrochemical reaction. The SI results showed that the water samples were oversaturated with carbonates and in equilibrium with evaporite minerals, except for halite and sylvite. The CAI was positive in 83% of the samples, indicating forward ion exchange and Ca dominance. The Gibbs diagram showed that rock weathering (carbonate dissolution) was the dominant process controlling water chemistry. The levels of Cd, Cr, Pb, As, Hg, Li, and Mo exceeded the WHO limits in all samples, while Ni and Co exceeded the limits in 51% and 65% of the samples, respectively. The HPI and HEI results showed that the water samples were highly contaminated with heavy metals and unsuitable for consumption. The HCA showed that the main factors affecting the water salinity were dissolved carbonates, gypsum, the major ions, and some heavy metals. The HCA also showed that the main variables contributing to water salinity were dissolved carbonates, gypsum, major ions, and heavy metals. The study concluded that the water samples are not suitable for drinking and other domestic uses, and groundwater treatment measures are recommended to protect the population from serious health risks.

The demand for sustainable, high-performance materials has led to increased interest in bio-based composites. However, optimizing the mechanical properties of such materials for engineering applications remains a challenge. This study addresses this gap by developing and characterizing an epoxy-based biocomposite reinforced with sugarcane bagasse particles, focusing on the influence of cyclic thermal treatment on its properties. The bagasse particles were chemically treated with 1 M NaOH to remove impurities, improve interfacial bonding with the epoxy matrix, and enhance the overall composite performance. The treated particles j were pulverized to 470 µm and incorporated into the epoxy matrix (0–20 wt%) using the hand layup method. The composites were divided into untreated and thermally treated groups, with the latter subjected to cyclic thermal treatment (100 °C for 3 h over 7 days). Mechanical, wear, and water absorption properties were evaluated, while fractured surface morphologies were analyzed using SEM. Results revealed that cyclic thermal treatment significantly enhanced the composites’ performance, with the 15 wt% heat-treated composite showing optimal properties: density of 1.102 g/cm ³ , flexural strength of 29.13 MPa, ultimate tensile strength of 103.50 MPa, impact strength of 3.49 kJ/m ² , hardness of 64.70 HS, and wear indices of 0.034 mg. These findings demonstrate that alkali treatment and cyclic thermal treatment synergistically enhance the performance of bio-composites, making them suitable for diverse applications, including automotive, aerospace, and other engineering fields.

Purpose Posterior fossa tumour (PFT) surgery carries a risk of mutism or severely reduced speech. As for higher-cognitive language functions, word-finding difficulties have been reported, but no study has compared pre- and postoperative word-finding speeds to identify impairment caused by surgery. The current study investigated changes in word-finding ability associated with PFT surgery and examined factors affecting postoperative ability. Method We included 184 children aged 5:0–17:9 years undergoing PFT surgery and assessed word-finding ability before and after surgery using a speeded picture-naming test. We compared postoperative word-finding performance with both preoperative performance and age-specific norms and examined factors affecting word-finding ability. Results We found no significant difference between pre- and postoperative performance, reflecting that some children exhibited better word-finding ability after surgery, others poorer. After surgery, 95% of the children performed two standard deviations above (slower than) age-specific norms. Tumour location in the fourth ventricle negatively affected postoperative word-finding ability (B = −4.09, p < 0.05). Conclusion For some children, PFT surgery leads to postoperative word-finding difficulties, emphasizing the importance of postoperative language assessments and interventions. Fourth-ventricle tumour location emerged as a risk factor for poorer postoperative word-finding ability, likely reflecting surgical damage to the dentato-thalamo-cortical pathway (DTCP).