Search Results (10)

Air pollution, largely driven by car traffic, poses significant challenges in many cities, including Košice, Slovakia. As the city explores micromobility as a part of its smart city initiatives and sustainable alternative to individual car use, understanding its spatial dynamics becomes essential. Despite the growing adoption of shared micromobility systems, research on their spatial patterns in Central Europe is still limited. This study analyzes over 900,000 trips made between 2019 and 2022 using bicycles, e-bikes, e-scooters, and e-mopeds in Košice’s dockless system. Using spatial analysis, we identified key hubs near public transport stops, pedestrian zones, and universities, highlighting how micromobility addresses the first/last mile transport challenge. A notable shift from bicycles to e-scooters was observed, enabling wider adoption in areas with fragmented terrain and neighborhoods farther from the city center. Our findings show a significant demand for shared micromobility, indicating its potential to reduce urban car dependency and support smart and sustainable urban transport. However, winter months remain a challenge, with high smog levels but near-zero demand for shared micromobility. Full article

We report on the formation of silver nanoparticles by gas aggregation in a reaction chamber at room temperature. The size distribution of nanoparticles deposited on a silicon substrate for various lengths of an aggregation (high-pressure) chamber was investigated by atomic force microscopy. Nanoparticles were characterized by scanning and transmission electron microscopy and spectral ellipsometry. The physical shape of the nanoparticles and its distribution was correlated with their optical properties. Metal–dielectric nanocomposites were deposited employing simultaneous deposition of Ag NPs via high-pressure magnetron sputtering and the dielectric matrix was deposited via thermal evaporation. Pure and Eu-, Er-, and Yb-doped lithium fluoride was used as the dielectric host matrix. Optical transmittance of lithium fluoride containing silver nanoparticles was measured and their theoretical absorption cross-section calculated. The nanoparticles were also embedded in Eu³⁺-doped downshifting and Er³⁺- and Y^b3+-doped up-conversion materials to study their influence on emission spectra. Spectra of identical layers with and without nanoparticles were compared. Their transmittance at various annealing temperatures is also presented. Full article

We measured dynamics of solar-induced chlorophyll fluorescence at telluric oxygen absorption bands O₂A and O₂B in evergreen spruce and deciduous beech forests. Seasonal variations in fluorescence emissions were compared with NDVI. Daily changes in fluorescence emissions were compared with canopy shadow fraction (α_S) dynamics, which showed impact of branch and leaf positions on detected fluorescence signals based on comparison with canopy height model. Absorbed photosynthetically active radiation (APAR) was recognized as a large determinant of fluorescence changes within the O₂A band (SIFA), with R² > 0.68. Fluorescence within the O₂B band was more directly linked to NDVI. Although, the seasonal dynamics of fluorescence within the O₂B band (SIFB) were similar to SIFA in the spruce forest. In the beech forest, SIFB showed different seasonal dynamics as compared with SIFA. SIFA in the spruce forest showed a relationship to gross primary productivity (GPP), with R² = 0.48, and a relationship of R² = 0.37 was estimated for the SIFA-GPP connection in the beech forest. SIFB was better linked to seasonal GPP in the beech forest, but with a negative slope in the relationship with R² = 0.61. We have shown that measurements of passive fluorescence signals at telluric oxygen absorption bands can contribute to understanding to photosynthesis processes in forest canopies. Full article

Anaerobic digestion (AD) plants undoubtedly represent an integral and irreplaceable element in rural energy transition and sustainable waste management. In our study, we focus on an advanced understanding of the dynamics behind the changing perceptions of AD plants in host communities in Poland, Slovakia, and the Czech Republic. The surveyed AD plant case studies were selected to represent best-practice examples of AD plant operations in their countries. By means of a comparative survey in three host communities, we seek to learn more about the shift in perceptions of AD plants between their planning and operational phases. We find that, although our cases are considered best-practice examples of AD plant operations, their overall support in their communities dramatically dropped in the operational phase consequent to real-life experience with living in the neighbourhood of an AD plant. Additionally, our findings indicate that respondents who reported the most severe deterioration of AD plant perceptions were, surprisingly, those who had participated in the planning process more than other respondents. The most frequently mentioned type of participation in the planning phase was reported to be visits to the local administration office to inspect an AD plant’s planning documentation. We argue that deteriorating perceptions of best-practice examples of AD plant operations negatively impact the further development and acceptance of the biogas sector in Eastern Europe. The element of acceptance by the locals of AD plant operations urgently requires reflection in the definition of best practices to inspire and upgrade both existing and planned biogas energy projects. Full article

At the beginning of 2020, the world was swept with a wave of a new coronavirus disease, named COVID-19 by the World Health Organization (WHO 2). The causative agent of this infection is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The data available on one of the promising therapeutic agents—nucleotide analog remdesivir (Gilead Sciences number GS-5734)—were evaluated. These data were concerned with remdesivir activation from the prodrug to the active molecule—triphosphate containing 1′-cyano group and modified nucleobase. This triphosphate competes with the natural substrate adenosine triphosphate. Additionally, its mechanisms of action based on RNA and proofreading exonuclease inhibition, leading to the delayed RNA chain termination of infected cells, and basic pharmacological data were assessed. Additionally, the analytical determination of remdesivir and its metabolites in cells and body liquids and also some data from remdesivir use in other RNA infections—such as Ebola, Nipah virus infection, and Middle East Respiratory Syndrome (MERS)—were summarized. More recent and more detailed data on the clinical use of remdesivir in COVID-19 were reported, showing the intensive efforts of clinicians and scientists to develop a cure for this new disease. Remdesivir as such represents one of the more promising alternatives for COVID-19 therapy, however the current understanding of this disease and the possible ways of dealing with it requires further investigation. Full article

Cadmium (Cd) is a toxic heavy metal occurring in the environment as an industrial pollutant. The systematic accumulation of Cd in the human body may lead to major health problems. Quercetin (QE) is a natural flavonoid widely distributed in plants and is a part of human diet. Many studies have demonstrated the multiple benefits of QE to humans in protecting cells of our bodies. The aim of this study was to investigate the effect of QE and Cd on the proliferation of astrocytoma 1321N1 cells. Results indicated that the simultaneous exposure of the cells to 200 µM QE and 16 μM Cd significantly reduced cell viability to 6.9 ± 1.6% with respect to vehicle-treated cells. Other experiments of QE pre-treatment followed by the exposure to Cd alone or with QE indicated significant but decreased ability of QE or Cd to reduce proliferation of the cells compared to their co-incubation. Our study suggested a synergetic anti-proliferative interaction of Cd and QE in malignantly transformed cells. This adds new information regarding the biological effects of QE. Full article

Significant drying shrinkage is one of the main limitations for the wider utilization of alkali-activated slag (AAS). Few previous works revealed that it is possible to reduce AAS drying shrinkage by the use of shrinkage-reducing admixtures (SRAs). However, these studies were mainly focused on SRA based on polypropylene glycol, while as it is shown in this paper, the behavior of SRA based on 2-methyl-2,4-pentanediol can be significantly different. While 0.25% and 0.50% had only a minor effect on the AAS properties, 1.0% of this SRA reduced the drying shrinkage of waterglass-activated slag mortar by more than 80%, but it greatly reduced early strengths simultaneously. This feature was further studied by isothermal calorimetry, mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Calorimetric experiments showed that 1% of SRA modified the second peak of the pre-induction period and delayed the maximum of the main hydration peak by several days, which corresponds well with observed strength development as well as with the MIP and SEM results. These observations proved the certain incompatibility of SRA with the studied AAS system, because the drying shrinkage reduction was induced by the strong retardation of hydration, resulting in a coarsening of the pore structure rather than the proper function of the SRA. Full article

Seven new oxime-based acetylcholinesterase reactivators were compared with three currently available ones (obidoxime, trimedoxime, HI-6) for their ability to lessen cholinesterase inhibition in blood and brain of cyclosarin-treated rats. Oximes were given at doses of 5% their LD₅₀ along with 21 mg/kg atropine five min before the LD₅₀ of cyclosarin (120 ug/kg) was administered. Blood and brain samples were collected 30 minutes later. The greatest difference between acetylcholinesterase inhibition in blood of cyclosarin-treated rats was found after administration of HI-6 (40%), compared to 22% for trimedoxime and 6% for obidoxime. Only two of the seven newly synthesized oximes had any effect (K203 at 7%, K156 at 5%). Effective oximes against cyclosarin-inhibited plasma butyrylcholinesterase were HI-6 (42%), trimedoxime (11%), and K156 (4%). The oximes were less effective in brain than in blood, with reactivation values for HI-6 30% against acetylcholinesterase and 10% against butyrylcholinesterase. Values for newly synthesized oximes were less than 10% for K206, K269 and K203. Full article

Cholinesterase activity in blood of laboratory rats was monitored. Rats were intoxicated with paraoxon at dosis of 0 – 65 – 125 – 170 – 250 – 500 nmol. The 250 nmol dose was found to be the LD₅₀. An electrochemical sensor was found useful to provide information about cholinesterase activity. The decrease of cholinesterase activity was correlated to intoxication symptoms and mortality level. It was found that the symptoms of intoxication are not observed while at least 50% of cholinesterase activity in blood remains. The minimal cholinesterase activity essential to survival is around 10%, when compared with the initial state. No changes in levels of low moleculary weight antioxidants were observed. Full article

The aim of this work is to investigate sunflower plants response on stressinduced by silver(I) ions. The sunflower plants were exposed to silver(I) ions (0, 0.1, 0.5,and 1 mM) for 96 h. Primarily we aimed our attention to observation of basic physiologicalparameters. We found that the treated plants embodied growth depression, coloured changes and lack root hairs. Using of autofluorescence of anatomical structures, such aslignified cell walls, it was possible to determine the changes of important shoot and rootstructures, mainly vascular bungles and development of secondary thickening. Thedifferences in vascular bundles organisation, parenchymatic pith development in the rootcentre and the reduction of phloem part of vascular bundles were well observable.Moreover with increasing silver(I) ions concentration the vitality of rhizodermal cellsdeclined; rhizodermal cells early necrosed and were replaced by the cells of exodermis.Further we employed laser induced breakdown spectroscopy for determination of spatialdistribution of silver(I) ions in tissues of the treated plants. The Ag is accumulated mainlyin near-root part of the sample. Moreover basic biochemical indicators of environmentalstress were investigated. The total content of proteins expressively decreased withincreasing silver(I) ions dose and the time of the treatment. As we compare the resultsobtained by protein analysis – the total protein contents in shoot as well as root parts – wecan assume on the transport of the proteins from the roots to shoots. This phenomenon canbe related with the cascade of processes connecting with photosynthesis. The secondbiochemical parameter, which we investigated, was urease activity. If we compared theactivity in treated plants with control, we found out that presence of silver(I) ions markedlyenhanced the activity of urease at all applied doses of this toxic metal. Finally we studiedthe effect of silver(I) ions on activity of urease in in vitro conditions. Full article