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István Csarnovics,1 Julia Burunkova,2 Danara Sviazhina,2 Evgeniy Oskolkov,2 George Alkhalil,2 Elena Orishak,3 Ludmila Nilova,3 István Szabó,1 Péter Rutka,1 Krisztián Bene,4 Attila Bácsi,4 Sándor Kökényesi1 1Institute of Physics, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary; 2International Scientific and Research Institute of Bioengineering, School of Photonics, ITMO University, St., Petersburg, Russian Federation; 3Department of Medical Microbiology, Faculty of Preventive Medicine, North-Western State Medical University Named After I.I. Mechnikov, St., Petersburg, Russian Federation; 4Department of Immunology, Faculty of Health, University of Debrecen, Debrecen, HungaryCorrespondence: István CsarnovicsUniversity of Debrecen, Faculty of Science and Technology, Institute of Physics, Bem sq 18/a, Debrecen 4026, HungaryEmail csarnovics.istvan@science.unideb.huIntroduction: In this work we selected components, developed technology and studied a number of parameters of polymer nanocomposite materials, remembering that the material would have high optical and good mechanical characteristics, good sorption ability in order to ensure high value of the optical signal for a short time while maintaining the initial geometric shape. In addition, if this nanocomposite is used for medicine and biology (biocompatible or biocidal materials or the creation of a sensor based on it), the material must be non-toxic and/or biocompatible. We study the creation of polymer nanocomposites which may be applied as biocompatible materials with new functional parameters.Material and Methods: A number of polymer nanocomposites based on various urethane-acrylate monomers and nanoparticles of gold, silicon oxides, zinc and/or titanium oxides are obtained, their mechanical (microhardness) properties and wettability (contact angle) are studied. The set of required, biology-related properties of these materials, such as toxicity and sorption of microorganisms are also investigated in order to prove their possible applicability.Results and Discussion: The composition of the samples influences their microhardness and the value of contact angle, which means that varying with the monomer and the metallic, oxide nanoparticles composition, we could change these parameters. Besides it, the set of required, biology-related properties of these materials, such as toxicity and sorption of microorganisms were also investigated in order to prove their possible applicability. It was shown that the materials are non-toxic, the adhesion of microorganisms on their surface also could be varied by changing their composition.Conclusion: The presented polymer nanocomposites with different compositions of monomer and the presence of nanoparticles in them are prospective material for a possible bio-application as it is biocompatible, not toxic. The sorption of microorganism could be varied depending on the type of bacterias, the monomer composition, and nanoparticles.Keywords: polymer nanocomposites, metallic nanoparticles, oxide nanoparticles, biocompatible materials, microhardness

We have previously characterized morphologic features of wounding-induced angiogenesis that occurs in response to acute and chronic gastric mucosal injury. As a means of investigating the molecular mechanisms underlying gastric angiogenesis, microvascular endothelial cells were isolated from stomachs of normal (non-injured) rats. The isolation procedure adapted and combined aspects of previous methods and employed positive selection using magnetic beads coated with monoclonal antibody specific for rat CD31 (PECAM-1), a cell surface marker restricted to platelets, monocytes, T lymphocytes and endothelial cells. The isolated microvascular endothelial cells expressed vascular endothelium-specific antigen and the endothelial-specific receptors, Tie2 and flt-1 (VEGFR1). When plated on growth factor-reduced matrigel, the isolated microvascular endothelial cells formed capillary-like structures reflecting in vitro angiogenesis. These cells were also responsive to vascular endothelial growth factor, VEGF, further verifying their endothelial nature. The rat microvascular endothelial cells isolated by this procedure should be useful in delineating molecular mechanisms and regulation of the angiogenesis that is essential for the healing of acute and chronic gastric injury.

The effects of exogenous ATP on Ca2+ signaling and wound healing were investigated in rat gastric microvascular endothelial cells (RGMEC). ATP (10 microM) triggered a significant rise in intracellular Ca2+ concentration ([Ca2+]i) from 46+/-2 nM at baseline to peak values averaging 283+/-31 nM (n = 5 experiments, 132 cells). Return to the basal [Ca2+]i was delayed by slowly declining plateau phase that persisted for 200+/-30 s. Removal of extracellular Ca2+ did not significantly affect the peak rise in [Ca2+]i, but reduced the plateau. ATP (10 microM) also significantly increased the migration of RGMEC in a wounded monolayer. Addition of the non-subtype selective purinergic receptor antagonist, suramin, abrogated the effects of ATP on [Ca2+]i and migration. We conclude that local elevation of ATP acting through purinergic receptors induce Ca2+ signals in RGMEC and may contribute to endothelial cell migration.

Apoptosis a programmed cell death, is an essential mechanism of eliminating damaged or aged cells and thus to maintain tissue integrity. There are two central pathways that lead to apoptosis: a) the positive induction by ligands (death factors) binding to plasma membrane receptors (death factor receptors) and b) negative induction by the loss of suppressor activity. The common execution mechanisms of apoptosis consist of the activation of cytosolic aspartate-specific proteases (ICE-proteases) termed caspases, which can be activated via various intracellular pathways. In the stomach, mucosal surface epithelial cells are constantly exfoliating to the gastric lumen and completely replaced within 3-5 days under physiological conditions. Apoptosis has been reported to take place in all regions of the stomach with apoptotic cells occurring predominantly in the superficial parts of the gastric glands, at a rate of 2-3% for all cells. Following mucosal injury (e.g. ulcer development), apoptosis rapidly increases and remains elevated for 2-3 months. In a 3-month old ulcer scar, the apoptosis rate of mucous, parietal, chief and endocrine cells was found to be similar to that of normal gastric mucosa. Helicobacter pylori (H. pylori) infection induces apoptosis in the gastric mucosa and this action appears to be independent of VacA cytotoxin of H. pylori strains. Nonsteroidal anti-inflammatory drugs (NSAIDs), especially cyclooxygenase-2 (COX-2) inhibitors are potent inductors of gastric epithelial cell apoptosis. However, they can abrogate apoptosis or proliferation effects induced by H. pylori. Many details of the exact intracellular and molecular mechanisms regulating apoptosis in gastric mucosa remain to be elucidated.

Digital technologies can help farmers produce safe, sustainable, high-quality food while contributing to the fight against effects of abiotic and edaphic factors. Due to digitalization, a paradigm shift occurred in agriculture, which boosted sensor technology's rapid development, especially soil sensors. Using sensors and the digital knowledge of soil properties, farmers can better understand the needs of the fields and cultivated plants on a micro-scale, thereby saving resources and putting less strain on our environment. The relative salinity of our soils is an important aspect because of the impact on production costs and yield. The future of site-specific crop production is moving towards a sensor-based on-the-go measurement approach because obtaining important soil characteristics quickly and cheaply is still one of the biggest challenges in precision agriculture today. Measuring soil electrical conductivity (EC) could offer an opportunity to overcome these limitations if the different salt components of soil could be separated by analytical methods. In our study, we present a calibration model based on conductometry with which the selective potassium and calcium content can be determined in the laboratory under controlled conditions. Solutions containing K+ and Ca2+ cations in the concentration determined in the experimental model were mixed and measured by changing the frequency of the measuring current. In this study, measurements proved that a mathematical relationship can be used to describe the relationship between the composition and concentration of the two-component solution, the measurement frequency and the conductivity. The potassium (K) and calcium (Ca) content of the solution can be separated from each other, and a regression calibration curve can be recorded, from which the proportion of potassium and calcium in the given solution can be determined as a function. [ABSTRACT FROM AUTHOR]