Slovak Academy of Sciences

The focus of this article is on exploring the concept of abstract homogeneity in relation to partially ordered sets. Our study delves into various properties of this notion, including self-homogeneity. We then apply these concepts to the practical area of image processing, demonstrating their relevance. Our application of abstract homogeneous functions in computer vision surpasses classical edge detection methods and approaches state-of-the-art results, highlighting their potential showing that a suitable family of functions for this task are the abstract homogeneous ones. Additionally, we improve these results by creating consensus feature images, which aggregate features to enhance the effect of abstract homogeneity. This method offers a subtle yet effective improvement in image processing tasks.

This study addresses the scientific question of how lead-free double perovskites Na2InGaCl6 and Na2InGaI6 can serve as sustainable materials for next-generation thermoelectric and optoelectronic applications by evaluating their structural, optoelectronic, mechanical, and thermoelectric properties. Using first-principles calculations with GGA and mBJ-GGA methods within the Wien2K computational framework, we examine whether these materials properties make them viable alternatives to conventional lead-based perovskites. The electronic band gaps (1.98 eV for Na2InGaCl6 and 0.30 eV for Na2InGaI6) calculated by using the Tb-mBJ potential suggest their suitability for optoelectronic applications. We found that when the halogen anions change from Cl to I, the electronic band gap mitigates. The compound’s structural stability is verified by the Goldsmith tolerance factor (tG) and negative formation energy validates their thermodynamic and structural stability. The elastic properties represent that both examined compounds are ductile and mechanically stable. The optical absorption results reveal that Na2InGaI6 absorbs a 128–471 nm wide range of UV-Visible electromagnetic radiations, which makes it a potential candidate for optoelectronic and solar cell applications. Furthermore, the transport parameters were computed by employing Boltztrap code. These compounds are appropriate for thermoelectric applications because of their large Seebeck coefficient (S) and ultralow lattice thermal conductivity, which further improve ZT. It demonstrates that Na2InGaX6 (X = Cl, I) has potential for use in solar cells and thermoelectric generators as sustainable and eco-friendly energy sources by confirming their stability, appropriate bandgaps, and remarkable thermoelectric qualities.

Vimentin, an abundant intracellular cytoskeletal protein, is secreted into the extracellular space, where it can amplify tissue destruction in inflammatory diseases. The mechanisms by which inflammation promotes the release of extracellular vimentin (ECV) are not defined. In human subjects, we found > twofold higher levels of ECV in gingival crevicular fluid from periodontitis sites with inflammation compared with healthy sites. In cultures of human gingival fibroblasts (hGFs) treated with 1% serum or IL‐1β (10 ng/mL) to model tissue injury or inflammation, respectively, we found that 1% serum increased ECV release > 11‐fold while IL‐1β further enhanced release 17‐fold. Mass spectrometry of vimentin immunoprecipitates identified Annexin A2 (AnxA2), a Ca²⁺‐dependent phospholipid‐binding protein, as a potential binding protein of ECV, which was confirmed by immunoprecipitation of cultured hGFs and immunostaining of inflamed human gingiva. IL‐1β treatment enhanced the abundance of AnxA2 and vimentin in membrane fractions prepared by sucrose gradients of hGF lysates. IL‐1β increased colocalization of ECV and AnxA2 at the outer aspect of the plasma membrane of intact hGFs. Knockdown of AnxA2 with siRNA or inhibition of the unconventional secretory pathway reduced ECV release from hGFs. These findings indicate that the production of ECV by hGFs in response to inflammation is mediated by an AnxA2‐dependent, unconventional secretory pathway that may play a role in amplification of the inflammatory response.

In this study, we derive the characteristic function of the multivariate folded normal distribution, a distribution that arises when the magnitudes—but not the signs—of a normally distributed random vector are of interest. The folded normal distribution is widely applicable across various fields. Thus, obtaining an analytical expression for its characteristic function is pivotal in understanding its fundamental properties. Moreover, this allows one to facilitate numerical evaluations of complex distributions involving linear combinations of absolute values of dependent normal variables. The derivation is based on a novel expression of the moment generating function, formulated using the cumulative distribution function of the multivariate normal distribution. To validate our findings, we present two examples using our MATLAB implementation. We compare the characteristic function for the sum of the absolute values of elements of a multivariate normal vector with the simulated empirical counterpart. Additionally, we derive the second mixed moment of the bivariate folded normal distribution from the moment generating function, demonstrating its agreement with known theoretical expressions.

A limited number of two-dimensional and three-dimensional materials under a constant pressure contract in volume upon heating isobarically; this anomalous phenomenon is known as the negative thermal expansion (NTE). In this paper, the NTE anomaly is observed in 1D fluids of classical particles interacting pairwisely with two competing length scales: the hard-core diameter a and the finite range a′>a of a soft repulsive potential component. If a′⩽2a, the pair interactions reduce themselves to nearest neighbours which permits a closed-form solution of thermodynamics in the isothermal–isobaric ensemble characterized by temperature T and pressure p. We focus on the equation of state (EoS) which relates the average distance between particles (reciprocal density) l to T and p⩾0. The EoS is expressible explicitly in terms of elementary or special functions for specific, already known and new, cases like the square shoulder, the linear and quadratic ramps as well as certain types of logarithmic interaction potentials. The emphasis is put on low-T anomalies of the EoS. Firstly, the equidistant ground state as the function of the pressure can exhibit, at some ‘compressibility’ pressures, a jump in chain spacing from a′ to a. Secondly, the analytical structure of the low-T expansion of l(T,p) depends on ranges of p-values. Thirdly, the presence of the NTE anomaly depends very much on the shape of the core-softened potential.

In this paper, we investigate the trajectory controllability of second order delayed discrete systems, aided by the representation of the solution. By employing two delayed discrete matrix functions, we establish sufficient and necessary conditions for Kalman-type controllability criterion in general case and special case. Examples are provided to illustrate the effectiveness of our theoretical results.

The Gasterosteidae, a family of marine, brackish and fresh water fish, is represented in Ukraine by the genera Pungitius and Gasterosteus . Among these, only the species Pungitius platygaster has hitherto been identified. However, our findings based on molecular cox1 DNA barcoding of collected material have confirmed the additional presence of Pungitius pungitius in the Dnipro River in Ukraine. This species has long remained hidden from scientific scrutiny, due to its diminutive size, lack of commercial significance and morphological similarities with a sister species. Our molecular DNA barcoding analysis has allowed the conclusive identification of this elusive species and provided an insight into its distribution and ecological relevance within inland waters in Ukraine. To examine and compare the haplotype diversity, we analysed our data of P. platygaster , P. pungitius and Gasterosteus aculeatus with those available in public repositories. Our findings demonstrate the presence of novel haplotypes in the region for all species. This support the theory P. pungitius is not a recent invasion in the region. Our findings demonstrate valuable role of advanced molecular methodologies in unravelling the biodiversity of aquatic ecosystems, particularly in the case of overlooked and often marginalized taxa. We also explore the current worldwide and regional conservation status of the species, contributing to the future studies and the population management.

Blind source separation refers to a set of techniques designed to uncover latent (i.e. directly unobservable) structures in data. Depending on user preferences and the chosen algorithm, latent components can be estimated either simultaneously or iteratively, one at a time. The latter approach is typically performed using component deflation. However, Camacho et al. (Chemom Intell Lab Syst 208:104212, 2021) showed that deflation can introduce spurious artefacts into the data, particularly when the latent components are estimated under constraints. This study explored the theoretical properties of deflation in the context of higher-order arrays and tensor decomposition. In certain cases, the tensor latent components may represent noise and must be removed before further decomposition to accurately reveal the underlying structure of the data. Building on the ideas presented in Camacho et al. (Chemom Intell Lab Syst 208:104212, 2021), we investigated whether specific forms of deflation can generate spurious artefacts in electroencephalogram (EEG) tensor data, particularly under nonnegativity or unimodality constraints, where orthogonality may lack a natural interpretation. Our results are demonstrated using two real EEG datasets and one simulated dataset.

Fluvial flooding is characterized by flood discharges, which cause overflowing of the river banks and endangering the adjacent floodplains. In this study, we studied the 3.1 km section of the Gidra River (western Slovakia), which belongs to critical river sections prone to fluvial flooding. We aimed to compare two approaches for fluvial flood hazard mapping. Hydraulic approach was performed with the use of MIKE + model while the GIS-based approach was carried out using the Height Above the Nearest Drainage (HAND) model. The research question was whether the HAND model is suitable for flood inundation modeling and comparable to hydraulic modeling in the specific valley type of terrain. To determine the peak discharges for 100 and 1000 return periods, we used the rainfall-runoff procedure via the STORAGE and COSMO4SUB models. Accuracy of HAND models, as respect to the hydraulic MIKE + models, was assessed with the use of the following metrics: Critical Success Index, F1-score, Bias, Precision, Recall, and Overall Accuracy. Based on the results, the HAND model underestimated the hydraulically modeled flood extents in case of both flood scenarios with Bias values of 0.84 (Q1000) and 0.87 (Q100). The Overall Accuracy resulted in values of 0.93 (Q1000) and 0.94 (Q100). We concluded that the HAND-based modeled flood extents for the studied river section had an acceptable accuracy in case of both flood scenarios. Focusing on the river located in a valley type of terrain, the usage of the HAND model is mainly for rapid and preliminary fluvial flood hazard mapping due to lower data and computational requirements in comparison to hydraulic models.

A R T I C L E I N F O Keywords: Sodium/calcium exchanger type 3 Proliferation Migration Breast cancer cell lines Colorectal cancer cell line Cervical cancer cell line Mitochondrial respiration A B S T R A C T The sodium/calcium exchanger (NCX) type 1 has been well described in various cancers, but little is known about the other two NCX types (NCX2 and NCX3). In this study, we used the selective blocker of NCX3-YM-244769 to investigate changes in apoptosis induction, migration, proliferation, intracellular calcium and ATP in four cancer cell lines-DLD1, HeLa, MDA-MB-231 and JIMT1. In all four cell lines we observed a concentration-dependent increase in the number of apoptotic cells, as well as reduced migration and proliferation. Induction of hypoxic conditions did not alter the response of these cells to YM-244769 in any of the above-mentioned parameters. These results indicate the role of NCX3 in cancer cell migration, proliferation and apoptosis, as inhibition of NCX1 by the specific blocker SEA0400 had no significant effect on these parameters. However, we verified the effect of NCX3 inhibition by using CRISPR/Cas9 to generate clones in which the SLC8A3 (NCX3) gene was deleted, and we obtained the same results. In addition, mitochondrial respiration was impaired in the clones with NCX3 knocked-out, suggesting that NCX3 also play a role in bioenergetics. In conclusion, we have clearly shown that NCX3 plays an important anti-apoptotic, pro-migratory and proliferative role in the cancer cells by affecting mitochondrial bioenergetics, thus supporting their survival and fate.

Bacteria-based self-healing concrete has emerged as a promising solution for enhancing structural durability by autonomously repairing cracks. However, the underlying transport mechanisms of healing agents and the efficiency of mineral precipitation remain inadequately modelled. This study presents a finite element modelling (FEM) approach to simulate the diffusion and reaction kinetics of self-healing bacterial agents in concrete microstructures. X-ray micro-computed tomography (Micro-CT) finite element meshes were utilized to accurately represent crack and pore geometries, while the diffusion-reaction equation governing calcium carbonate (CaCO3) precipitation was numerically solved using FEniCS. Key input parameters, including diffusion coefficients, precipitation rates, and healing efficiencies, were extracted from literature to ensure model validation. Simulations reveal that healing agent concentration follows a nonlinear diffusion pattern, with efficiency influenced by crack geometry and bacterial metabolic activity. Heatmaps and contour plots highlight healing agent dispersion, while time-dependent analysis indicates a 65.5% crack closure efficiency under optimal bacterial conditions. The proposed model effectively replicates experimental trends, demonstrating its applicability for predicting healing performance in realistic structural conditions. This study provides a computational framework that can be extended to optimize bacteria encapsulation strategies, healing kinetics, and long-term durability assessments in self-healing concrete.

Objectives This study describes the presence of glutathione peroxidase 3 (GPx3) in mice oocytes, preimplantation embryos (O/PEs), and female genital organs during the preimplantation period of pregnancy. Background Glutathione peroxidase 3, the antioxidant enzyme, is important in protecting cells against the oxidative stress. Methods O/PEs were isolated from genital organs of superovulated females for the immunofluorescence analysis and these organs were used for the immunohistochemistry to detect GPx3. Results GPx3 was present in all O/PEs, where it formed clusters diffusely in the cytoplasm, or under the cytoplasmic membrane. Moreover, GPx3 was likely indicated in nucleoli. GPx3 was found in the cytoplasm of granulosa-lutein cells as well as in follicular cells. The oocyte cytoplasm inside the ovary was negative. Oviductal epithelial cells before and after fertilization had different positivity patterns. Uterine luminal epithelial cells were negative before fertilization. After fertilization, a few positive luminal epithelial cells and a few cells of uterine glands had positive cytoplasm. Conclusion The differences of the GPx3 signal intensity in nucleoli of the zygote and the 2-cell embryo, and the different localization of GPx3 in the cytoplasm of 2-cell and 4-cell embryos may be the signs of the maternal-zygotic genome transition. Moreover, GPx3 may be significant during the preimplantation period of pregnancy in O/PEs and female genital organs, where it could protect cells from oxidative stress during the hormone and protein synthesis, and during the cell metabolism. The presence of cytoplasmic granules in epithelial cells of fallopian tube may indicate their secretion into the lumen of the organ to protect gametes and preimplantation embryos passing through. To our knowledge, this is the first study investigating GPx3 occurrence in mammalian preimplantation embryos.

We introduce a generalization of L-algebras motivated by investigations into the structure of quantum logic, termed quasi-L-algebras. After establishing the foundational structure theory for such quasi-L-algebras, we delve into the class of quasi-L-algebras, denoted as $\mathcal{Q}\mathcal{L}$, which forms a quasivariety. Utilizing the fact that every quasi-L-algebra can be embedded into the direct product of an L-algebra and a flat quasi-L-algebra, we determine a generator for $\mathcal{Q}\mathcal{L}$. Lastly, we explore congruence relations on a quasi-L-algebra L and their connections with ideals and weak ideals of L, as well as the ideals of the L-algebra R(L). We also propose a representation for congruence relations on each quasi-L-algebras.

The study addresses limitations of the 4-Component Thinking Styles Questionnaire (4-CTSQ) measuring actively open-minded thinking (AOT), close-minded thinking (CMT), preference for effortful thinking (PET), and preference for intuitive thinking (PIT). The aim was to validate the 4-CTSQ in a non-U.S./Canadian population, to explore the nomological networks of thinking styles, and to test whether the 4-CTSQ predicts unfounded beliefs over and beyond analytic thinking. The secondary aim was to address the issue of acquiescence linked with the one-directional wording of the items and to develop a balanced version of the 4-CTSQ (4-CTSQ-B). In two studies ( N 1 = 1,233, N 2 = 712), 4-factor models had an acceptable model fit, and both the 4-CTSQ and the 4-CTSQ-B predicted unfounded beliefs. Conceptual and psychometric issues with AOT and CMT were identified and possible solutions were discussed. The 4-CTSQ, and somewhat more so the 4-CTSQ-B, appear to be good scales sensitive to distinct thinking styles.

We investigated the contributions of female and male hosts to the structure of individual-based host-parasite networks, using 21 species of small mammals from two regions (West Siberia and eastern Slovakia) and two taxa of ectoparasitic arthropods (fleas and gamasid mites). We asked whether (a) the values of individual host position indices (individual strength, nested rank, the degree of individual specialization, and the eigenvector centrality) and individual host roles differed between female and male hosts in each network and (if yes) were associated with differences in the infestation levels, (b) differences between sexes (if any) were further translated into differences in the network structure (nestedness and network specificity), and (c) differences between female and male hosts in their positions and roles and the effect of these differences on the network structure differed between host-flea and host-mite networks. In the majority of individual-based host-ectoparasite networks, female and male hosts differed in their positions despite a general lack of differences in the infestation levels. The distribution of the roles played in a network mostly did not differ between sexes. The extent of position differences between sexes affected the structure of host-flea, but not host-mite, networks in terms of the network specificity. In addition, the occurrence and the direction of these differences (i.e., the greater value of the position index in either female or male hosts) often varied (a) between host-flea and host-mite networks in the same host, (b) between host species within host-flea and host-mite networks, and (c) between the two regions in the same host-flea or host-mite network. We conclude that differences in the positions of male and female hosts in individual-based host-parasite networks are mediated by host biology, parasite biology, and environmental factors. Supplementary Information The online version contains supplementary material available at 10.1007/s00436-025-08492-2.

Ryanodine receptors (RyRs) serve for excitation-contraction coupling in skeletal and cardiac muscle cells in a noticeably different way, not fully understood at the molecular level. We addressed the structure of skeletal (RyR1) and cardiac (RyR2) isoforms relevant to gating by Ca ²⁺ and Mg ²⁺ ions (M ²⁺ ). Bioinformatics analysis of RyR structures ascertained the EF-hand loops as the M ²⁺ binding inhibition site and revealed its allosteric coupling to the channel gate. The intra-monomeric inactivation pathway interacts with the Ca ²⁺ -activation pathway in both RyR isoforms, and the inter-monomeric pathway, stronger in RyR1, couples to the gate through the S23*-loop of the neighbor monomer. These structural findings were implemented in the model of RyR operation based on statistical mechanics and the Monod-Wyman-Changeux theorem. The model, which defines closed, open, and inactivated macrostates allosterically coupled to M ²⁺ -binding activation and inhibition sites, approximated the open probability data for both RyR1 and RyR2 channels at a broad range of M ²⁺ concentrations. The proposed mechanism of RyR operation provides a new interpretation of the structural and functional data of mammalian RyR channels on common grounds. This may provide a new platform for designing pharmacological interventions in the relevant diseases of skeletal and cardiac muscles. The synthetic approach developed in this work may find general use in deciphering mechanisms of ion channel functions.

Objectives This study aimed to assess the impact of intralesional bony overgrowth (ILBO) after cartilage repair on the integrity of opposing articulating cartilage (OpAC) using T2 mapping and to correlate these findings with clinical outcomes. Methods In this multicenter study, magnetic resonance imaging (MRI) examinations were performed in the follow-up after cartilage repair (Microfracturing (MFX) and Matrix-Induced Autologous Chondrocyte Implantation (MACI)) in 45 patients up to 5 years after surgery. T2 values of the OpAC after 3, 12, and 60 months in patients with and without ILBO after 60 months were conducted along with clinical assessments (International Knee Documentation Committee (IKDC) and Knee injury and Osteoarthritis Outcome Score (KOOS)). Results At 60 months post-surgery, 44.4% of patients presented with ILBO, which was associated with significantly higher T2 values in OpAC ( P = 0.004). A tendency toward increased T2 values was observed after 12 months, although this did not reach statistical significance ( P = 0.06). However, no significant differences were found in clinical outcomes between patients with or without ILBO, nor between those with or without T2 values comparable to reference cartilage. Conclusion ILBO significantly affects the biophysical MRI properties of OpAC as indicated by higher T2 values after 60 months. These alterations, though not reflected in any clinical score, can suggest potential long-term implications for cartilage degeneration and may inform future monitoring strategies for cartilage repair. Further research is required to evaluate the long-term effects of these altered mechanical impacts on articulating cartilage and their clinical implications.

Lignocellulosic biomass represents the largest available renewable source of carbon. It is a recalcitrant mixture of different polysaccharides and lignin. For its complete degradation, a large set of enzymes capable of cleaving its individual components is required. Several anaerobic bacteria produce high-molecular-weight multienzyme complexes called cellulosomes where the enzymes work in synergy for efficient degradation of the complex plant material. One of the anaerobic thermophilic cellulosome-forming bacteria is Acetivibrio clariflavus. Acetivibrio clariflavus was found to be one of the most abundant lignocellulose-solubilizing bacteria in various plant decaying environments. It produces sophisticated cellulosomal complex that is most similar to mesophilic Acetivibrio cellulolyticus cellulosome. In comparison with other anaerobic cellulosome-forming bacteria A. cellulolyticus and Acetivibrio thermocellus, A. clariflavus possesses lower number of cellulolytic enzymes. However, it is significantly better equipped for a degradation of hemicellulose, particularly xylan. Some strains, e.g., 4 - 2a, were also shown to utilize xylose. Efficient saccharification of plant biomass makes A. clariflavus a promising candidate for various biotechnological applications including biofuel production. Key points • Acetivibrio clariflavus is anaerobic thermophilic cellulosome–forming bacterium. • Its cellulosomes target mostly cellulose and hemicellulose, in particular xylan. • The strains share most of xylanolytic enzymes but differ in xylose utilization.