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We report on the design, fabrication, and experimental characterization of a free‐standing terahertz metasurface supporting quasi‐bound states in the continuum (quasi‐BICs). The metasurface, realized by laser cutting double‐slot apertures in a thin brass foil, exhibits a tunable transition from symmetry‐protected BICs to sharp Fano‐type resonances when structural asymmetry is introduced. Terahertz time‐domain spectroscopy measurements confirm high‐Q resonances in good agreement with simulations. Multipole decomposition reveals that the trapped mode response is dominated by the in‐plane electric quadrupole component, which governs the confinement and radiation properties of the quasi‐BIC. The free‐standing design eliminates substrate‐induced losses and opens a robust route toward versatile, high‐performance terahertz devices. These findings demonstrate the potential of quasi‐BIC metasurfaces as compact, tunable high‐Q resonators for applications in sensing, filtering, and terahertz photonics.

This work presents the design, the development and the experimental validation of a portable, low-cost sensing system for the detection of waterborne pollutants. The proposed system is based on Electrochemical Impedance Spectroscopy and PPF+Ni nanomembrane sensors. Designed in response to the increasing demand for in situ water quality monitoring, the system integrates a simplified, scalable EIS acquisition architecture compatible with microcontroller-based platforms. The sensing configuration utilises the voltage divider principle, ensuring simplicity in signal conditioning by allowing compatibility with different electrode types through passive impedance matching. In addition, new merit figures have been proposed and implemented to analyse the measures. The proposed platform was experimentally characterised for its measurement stability, accuracy and environmental robustness. Sensitivity tests using benzoquinone as a target analyte demonstrated the capability of detecting concentrations as low as 0.1 mM with a monotonic response over increasing concentrations. A comparative study with a commercial electrochemical system (PalmSens4) under identical conditions highlighted the higher resolution and practical advantages of the proposed method despite operating with a lower impedance range. Additionally, the system exhibited reliable discrimination across tested concentrations and greater adaptability for integration into field-deployable environmental monitoring platforms. Future developments will focus on optimising selectivity through new sensor materials and analytical modelling of uncertainty propagation in the analysis based on defined figures of merit.

A simplified design framework for narrowband terahertz thermal emitters based on a resonant Salisbury-type structure is investigated numerically. The structure consists of a metallic backreflector, a dielectric spacer, and a thin resonant layer with a Lorentz-type dielectric response. Using the transfer matrix method, we show that matching the intrinsic resonance of the resonant layer with an interference resonance of the Salisbury structure enables selective enhancement of a single emissivity peak without requiring time-consuming full-wave optimization at the initial design stage. The influence of spacer thickness, refractive index, and resonance strength on the spectral response is analysed, providing simple guidelines for tuning the emission frequency and suppressing parasitic peaks. A realistic implementation based on a graphene metamaterial layer on a silicon spacer is also investigated using finite-element simulations to demonstrate the applicability of the proposed design concept. The obtained emissivity and thermal emission spectra show that the approach can be used for the efficient design of spectrally selective terahertz thermal emitters in the 10–40 THz range.

Graphite nanoplatelets (GNPs)—the segregated ultra-high molecular weight polyethylene (UHMWPE)-based composites with hybrid filler—decorated with Fe3O4 were developed. Using X-ray diffraction and scanning electron microscopy, it was shown that the decorated component has the shape of separate granules, or their clusters were distributed evenly over the GNPs surface. The individual Fe3O4 nanoparticles are predominantly rounded, with diameters of approximately 20–60 nm. The use of GNPs/Fe3O4 as a filler leads to significant decreases in the percolation limit φc, 0.97 vol% vs. 0.56 vol% for GNPs/UHMWPE- and (GNPs/Fe3O4)/UHMWPE segregated composite material (SCM), respectively. Modification of the GNP surface with Fe3O4 leads to an essential improvement in the electromagnetic interference shielding due to enhanced microwave absorption in the 26–37 GHz frequency range in its turn by abundant surface functional groups and lattice defects of GNPs/Fe3O4 nanoparticles.

Graphite nanoplatelets (GNPs)-the segregated ultra-high molecular weight polyethylene (UHMWPE)-based composites with hybrid filler-decorated with Fe O were developed. Using X-ray diffraction and scanning electron microscopy, it was shown that the decorated component has the shape of separate granules, or their clusters were distributed evenly over the GNPs surface. The individual Fe O nanoparticles are predominantly rounded, with diameters of approximately 20-60 nm. The use of GNPs/Fe O as a filler leads to significant decreases in the percolation limit φc, 0.97 vol% vs. 0.56 vol% for GNPs/UHMWPE- and (GNPs/Fe O )/UHMWPE segregated composite material (SCM), respectively. Modification of the GNP surface with Fe O leads to an essential improvement in the electromagnetic interference shielding due to enhanced microwave absorption in the 26-37 GHz frequency range in its turn by abundant surface functional groups and lattice defects of GNPs/Fe O nanoparticles.

Graphite nanoplatelets (GNPs)—the segregated ultra-high molecular weight polyethylene (UHMWPE)-based composites with hybrid filler—decorated with Fe[sub.3]O[sub.4] were developed. Using X-ray diffraction and scanning electron microscopy, it was shown that the decorated component has the shape of separate granules, or their clusters were distributed evenly over the GNPs surface. The individual Fe[sub.3]O[sub.4] nanoparticles are predominantly rounded, with diameters of approximately 20–60 nm. The use of GNPs/Fe[sub.3]O[sub.4] as a filler leads to significant decreases in the percolation limit φc, 0.97 vol% vs. 0.56 vol% for GNPs/UHMWPE- and (GNPs/Fe[sub.3]O[sub.4])/UHMWPE segregated composite material (SCM), respectively. Modification of the GNP surface with Fe[sub.3]O[sub.4] leads to an essential improvement in the electromagnetic interference shielding due to enhanced microwave absorption in the 26–37 GHz frequency range in its turn by abundant surface functional groups and lattice defects of GNPs/Fe[sub.3]O[sub.4] nanoparticles.

We propose a model of tunable THz metamaterials. The main advantage is the blueshift of resonance and phase tunability due to toroidal excitation in planar metallic metamolecules with incorporated silicon inductive inclusions.

The article focuses on the optimization of the extraction process of biologically active compounds (BAC) from grape marc—a by-product of the wine industry. The influence of temperature, specifically 30 °C, 45 °C and 65 °C, and ethanol concentration in solutions, specifically 0–96% (v/v) on the extraction yield of polyphenols, flavonoids, tannins and anthocyanins, were investigated. The composition of individual polyphenols, anthocyanins and organic acids, antioxidant activity (DPPH and ABTS) and CIELab chromatic characteristics of the grape marc extracts (GME), were characterized. The microbiostatic and microbicidal effects in direct contact of GME with pathogenic microorganisms, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, were determined in vitro. The influence of extraction parameters on the total polyphenol content (TPC), total flavonoid content (TFC), tannin content (TC), total anthocyanin content (TAC) and their interdependencies were studied using information analysis. A mathematical model was developed on cubic spline functions. The analysis of individual compounds showed the presence of a wide range of flavonoids (procyanidin B2, procyanidin B1, hyperoside and quercetin), flavones (catechin), hydroxybenzoic acid derivatives (gallic, protocatechuic, p-hydroxybenzoic acids, m-hydroxybenzoic acid, syringic acid), hydroxycinic acid derivatives and ferulic acid methyl ester. The malvidol-3-glucoside was the main anthocyanin identified in the extract. A high amount of tartaric acid was also found. GME showed significant antimicrobial activity against Gram-positive bacteria and lower activity against Gram-negative bacteria.

The problem of functional foods with bioactive components of natural origin is current for the food industry. Plant extracts rich in polyphenols with antioxidant and antimicrobial activity are a promising source for use in improving the quality and characteristics of fresh meat and meat products. In this context, the purpose of the present study was to evaluate the physico-chemical, microbiological, sensory properties of sausages prepared with the addition of lyophilized extract of basil, thyme or tarragon. For the beginning, the total amount of polyphenols, the antioxidant and antimicrobial activity of the extracts obtained from three spices were evaluated. In the sausages previously infected with Staphylococcus aureus and Escherichia coli it was observed that there is a much larger number of colonies of microorganisms in the control sample compared to the other samples within 24 and 48 h. Moreover, following the addition of sausage extracts, no changes were found regarding their sensory acceptability.

The article investigated the antioxidant and antimicrobial activity of extracts from two aromatic plants—Satureja hortensis L. (SE) and Rosmarinus officinalis L. (RE), encapsulated in alginate, on—yogurt properties. The encapsulation efficiency was controlled by FTIR and SEM analysis. In both extracts, the individual polyphenol content was determined by HPLC–DAD–ESI-MS. The total polyphenol content and the antioxidant activity were spectrophotometrically quantified. The antimicrobial properties of SE and RE against gram-positive bacteria (Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, Geobacillus stearothermophilus), gram-negative bacteria (Escherichia coli, Acinetobacter baumannii, Salmonella abony) and yeasts (Candida albicans) were analyzed in vitro. The encapsulated extracts were used to prepare the functional concentrated yogurt. It was established that the addition of 0.30–0.45% microencapsulated plant extracts caused the inhibition of the post-fermentation process, the improvement of the textural parameters of the yogurt during storage, thus the shelf life of the yogurt increased by seven days, compared to the yogurt simple. Mutual information analysis was applied to establish the correlation between the concentration of the encapsulated extracts on the sensory, physical-chemical, and textural characteristics of the yogurt.