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Impact of Microplastics on Forest Soil Properties in Pollution Hotspots in Alluvial Plains of Large Rivers (Morava, Sava, and Danube) of Serbia
No full textPlastic pollution has become a major environmental problem, while the products
of its degradation, microplastics (MPs), appear everywhere on Earth. Data on MPs in
agricultural soils have appeared lately, but a significant knowledge gap exists regarding
forest soils. In Serbia, municipal waste is often dumped in forests, creating environmental
problems that have not been documented. To explore the impact of waste dumping
and MPs on forest fluvisols, we evaluated MPs from topsoils of three waste dumps and
adequate visibly plastic non-contaminated forest sites located in alluviums of the largest
rivers in Serbia. For assessing the influence of environmental factors on soil MPs, samples
were taken in three forest vegetational seasons, in two years. The impact of MPs on soil
structure, chemistry, and microbial respiration (MR) was examined. Undisturbed soil
columns from uncontaminated sites with added known MP particles were used to estimate
the dynamic of MP transfer through the topsoil. Large aggregate formation, soil coarse sand
content, specific mass, porosity, and available P, but not MR were affected by contamination.
Seasonal and annual environmental changes significantly influenced the behavior of MPs
in forest luvisols. MPs effectively penetrated the deeper layers of soil columns within
3 months, with strong accumulation in the 0–10 cm layer
THE VIEWS OF TOURISM STUDENTS ON THE SUBJECT OF THE CULTURAL AND ARTISTIC HERITAGE OF SERBIA
No full textThis work presents the research conducted among students of the Academy of Professional Studies Šumadija, Department of Aranđelovac, enrolled in the Tourism and Hospitality Management program. Within the study, students expressed their attitudes regarding three groups of statements: 1) the mutual influence of the curriculum and knowledge that students acquire on one and trips and visits to places with cultural and artistic content on the other side; 2) the influence of curriculum on the understanding of cultural and artistic heritage; and 3) its influence on the understanding of contemporary cultural and artistic events and the development of tourism in Serbia. We used exploratory factor analysis for statement grouping and the Likert scale to present the attitudes. We found no significant difference in attitudes between the groups of students from different years. The results could be a starting point for all curriculum developers in higher education and for improving tourism education
Antibacterial Activity of Essential Oil of Satureja montana L. against Reproductive Tract Pathogens of Cattle
No full textPrekomerna upotreba antimikrobnih agenasa dovela je do razvoja rezistencije bakterijskih sojeva na određene antibiotike, prisustva rezidua antibiotika u proizvodima životinjskog porekla i drugih negativnih posledica. Kako bi se prevazišli ovi problemi, širom sveta se vrše ispitivanja efikasnosti brojnih lekovitih biljaka, zbog njihovih antimikrobnih svojstava. Cilj ove studije bio je da se istraži antibakterijska aktivnost etarskog ulja (EU) dobijenog iz Satureja montana L. protiv patogena izolovanih iz materice krava, terenskih sojeva i bakterijskih sojeva dobijenih iz Američke kolekcije tipičnih kultura (ATCC): Trueperella pyogenes, Escherichia coli, Pasteurella spp., Staphylococcus aureus, Streptococcus spp. i Fusobacterium necrophorum subsp. necrophorum. Hemijski profil EU analiziran je pomoću gasne hromatografije povezane sa masenom spektrometrijom (GC-MS). Antibakterijska osetljivost patogena testirana je u uslovima in vitro korišćenem Disk Difuzionog Testa, dok je za određivanje Minimalne Inhibitorne Koncentracije (MIK) korišćen Agar Dilucioni Test (ADT) i Mikrodilucioni Test (MT) (za anaerobne sojeve). Rezultati antimikrobne aktivnosti, dobijeni različitim testovima, ukazuju da je EU Satureja montana sa dominantnim aktivnim supstancama p-cimen (42,83%) i karvakrol (28,11%) od ukupno 17 identifikovanih hemijskih komponenti, moćan antimikrobni agens. Od testiranih bakterijskih izolata, 67,2% je bilo osetljivo, 32,8% je bilo sa srednjim stepenom osetljivosti, a 0% testiranih različitih bakterijskih izolata je bilo potpuno otporno. Pored toga, izračunate MIK vrednosti za ADT i MDT su bile <1 µl/mL za antibakterijske izolate svih vrsta, što se smatra vrlo efikasnim. Dobijeni rezultati ukazuju na visok antimikrobni potencijal EU Satureja montana, koje se može koristiti za kontrolu različitih infekcija bakterijskog porekla, uključujući i one koje dovode do poremećaja u reproduktivnom sistemu krava, kao što je endometritis.The abundant use of anti-infective agents resulted in developing resistance of bacteria strains to certain antibiotics, the presence of antibiotic residues in animal products and other negative consequences. To overcome these problems, a variety of medicinal plants have been screened worldwide for their antimicrobial properties. The aim of the present work was to examine the antibacterial activity of essential oil (EO) obtained from Satureja montana L. against pathogens from animal uterus, isolates (field strains) and bacterial strains obtained from American type culture collection (ATCC): Trueperella pyogenes, Escherichia coli, Pasteurella spp., Staphylococcus aureus, Streptococcus spp. and Fusobacterium necrophorum subsp. necrophorum. Chemical profile of EO was analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Antibacterial sensitivity of pathogens was tested in vitro using a Disc diffusion method, and for determination of the minimal inhibitory concentration (MIC), Agar Dilution Test (ADT) and Microdilution assay (MDT) (for anaerobic strains) were used. The results of antimicrobial activity obtained from different tests suggest that EO of S. montana, consist mainly from p-cymene (42.83%) and carvacrol (28.11%) of the total 17 compounds identified, is potent antimicrobial agent with 67.2% susceptible, 32.8% intermediate and 0% resistant bacterial isolates of different species. Moreover, calculated MIC values on both ADT and MDT were <1 µl/mL for bacterial isolates from all species, which is considered highly effective. The obtained results suggest high antimicrobial potential of S. montana EO which can be used for the treatment of various diseases of bacterial origin, including those affecting the female reproductive tract in cows such as endometritis
Assessment of the ecological status of five water supply reservoirs based on the fish community
No full textCilj ovog istraživanja bio је da se uporedi status i kvalitet vode u akumulacijama Gruža, Garaši, Stubo-Rovni, Ribnica i Brestovac, na osnovu kvalitativnog i kvantitaivnog sastava riblje zajednice. Ustanovljeno je prisustvo 17 vrsta iz devet familija. Najveći broj vrsta zabeležen je u akumulaciji Gruža, a najmanji u akumulaciji Stubo-Rovni. Vode svih ispitivanih akumulacija pripadaju polisaprobnim vodama, osim Gruže koja pripada β mezosaprobnim vodama II klase boniteta. Akumulacije Gruža, Garaši i Ribnica imale su kvalitet vode koji spada u II-III klasu, dok je kod akumulacija Stubo-Rovni i Brestovac zabeležena III-IV klasa. Kvalitet vode u ispitivanim akumulacijama nije na zadovoljavajućem nivou.This study aimed to compare the status and water quality (WQ) in five reservoirs (Gruža, Garaša, Stubo-Rovni, Ribnica, Brestovac) based on the qualitative and quantitative composition of the fish community. The presence of 17 species from nine families was established. The greatest number of species was recorded in Gruža, and the lowest in Stubo-Rovni. The waters of all reservoirs belong to polysaprobic waters, except for Gruža, which belongs to β-mesosaprobic waters of class II. Gruža, Garaši and Ribnica had WQ that belongs to class II-III, while in Stubo-Rovni and Brestovac class III-IV was recorded. The WQ in the studied reservoirs is unsatisfactory
Circular Economy as a Driver of Sustainable Growth: Quantitative Analysis of the Role of Recycling and Secondary Raw Materials in the EU
No full textThe aim of this research is to determine the significance of the impact of selected environmental protection indicators, with a focus on waste management, on the sustainability of economic growth in EU countries (21 member states) over the period 2013–2022. To conduct this analysis, four independent variables were selected, belonging to the domains of waste management the (recycling rate of municipal waste and recycling rate of packaging waste by type of packaging) and secondary raw material management (the circular material use rate and trade in recyclable raw materials, imports from outside the EU27). Sustainable economic growth was measured by gross domestic product per capita (GDP per capita), which serves as the dependent variable in this study. The aforementioned independent variables can also be categorized as circular economy (CE) indicators, which have been gaining increasing relevance in the EU context. Using a panel regression analysis, the potential influence of CE indicators on sustainable economic growth was examined both over time and across entities, through the lens of waste management. The statistical analysis was conducted by applying four econometric models: pooled OLS (POLS), fixed effects (FEs), random effects (REs), and mixed effects (MEs). The results of the analysis confirmed several specific hypotheses (depending on the model used), which posit a statistically significant positive impact of CE variables on GDP per capita
Reconstruction of the enigmatic pre-Variscan paleogeographic configuration of the western peri-Moesian realm (Carpathian-Balkans, eastern Serbia): An insight into Devonian small-scale continental and paleo-oceanic units
No full textThe Carpathian-Balkans provide insight into how two distinct but limited-sized north Gondwanan ribbon-shaped paleocontinents interacted prior to the Variscan Devonian collisional onset: (i) the drifted “Carpathian-Balkan microcontinent” (Serbo-Macedonian/Supragetic/Getic(Kučaj)) and (ii) the already amalgamated Avalonian Danubian-Moesian basement fragment with its Devonian suture elements. These two crustal fragments were separated by the intervening Rheic Ocean during the Devonian. Despite the investigated eastern Variscan collisional assembly being stacked near the overprinted promontory of the East European Craton, its sliced basement segments and their Devonian record are well exposed in eastern Serbia. The synthesis reveals that the sliced Carpathian-Balkan inliers play a crucial role in understanding the lithospheric-scale movement of smaller continental terranes from north Gondwana and their suturing modes related to the surrounding Paleozoic oceans. An analysis of geochemical, paleogeographic, and regional geological data reveals that continental and oceanic paleoenvironments existed prior to and during the Devonian period, merging with the already amalgamated Danubian block and the Moesian microplate. Nonetheless, despite the well-preserved Devonian record found in eastern Serbia, the Romanian South Carpathians, and western Bulgaria, only a limited number of reconstructions clarify the pre-Variscan tectono-paleogeographic setting.
After a few rift-drift cycles connecting north Gondwana and southern Laurussia, the tectonic transport of Cadomian to Cenerian peripheral terranes from northern Gondwana begun with the post-Ordovician rifting off. The rifting led to the formation of narrow, elongated crustal segments. The outboard Lower Paleozoic ribbon-shaped paleocontinent, including its Carpathian-Balkan continental fragment, occupied a position between two principal Paleozoic oceans. On the southern flank of the exotic narrow Lower Paleozoic microcontinent, we demonstrate for the first time the presence of a continental extension of Devonian age, likely associated with the adjacent Paleotethyan Ocean. The synthesis further demonstrates that the volcano-sedimentary protoliths of Devonian-aged greenschist facies rocks, which traverse the continental Serbo-Macedonian/Supragetic/Getic Devonian microcontinent, serve as markers of Early Devonian (back-arc) rifting. On its opposite Eurasian flank towards Danubian/Moesia, following the accumulation of Silurian–Early Devonian deep-water sediments, the Kučaj(Getic) turbidites, along with the expanding Middle to Late Devonian oceanic crust (Danubian ophiolites), belonged to the Rheic Ocean. The geochemical modeling of Devonian ophiolites reveals that this Balkan-Carpathian ocean displays both mid-ocean ridge basaltic (Tisoviţa Iuţi, Deli Jovan) and volcanic arc/back-arc signatures (Zaglavak, Tcherni Vrah). The extracted petrographic and regional geological constraints confirm the short transport of eroded material from the eroded Serbo-Macedonian/Supragetic narrow elongated landmass into the Late Devonian (Carboniferous) Kučaj(Getic) trench turbidites. Geochemical signatures outline the intraoceanic character of this frontal pre-Variscan subduction-driven active margin. The proposed new Devonian reconstruction updates the existing paleogeographic constraints on the opposite Avalonian block, revealing that the narrow Devonian ocean and its subduction beneath the Avalonian “micro-terranes” (Danubian/Moesia) produced an epicontinental basin with Devonian volcanism assigned to the Hanseatic-type rifting off processes
Enhanced multifunctionality through the combined effect of lead-free piezoelectric and magnetostrictive phases in the polymer matrix composite
No full textIn this work, the production of polymer composites by hot pressing, incorporating barium calcium zirconium titanate (BCZT) and cobalt ferrite (CF) particles into a polyvinylidene difluoride (PVDF) matrix, was explored for the first time. The effect of CF content on the material’s functional properties and the influence of the active phase quantity on the final flexible films were evaluated. Results showed that neither the CF content nor the active phase amount affected the formation of the electro-active PVDF β-phase. Dielectric permittivity was slightly influenced by CF content, but mainly increased due to the BCZT filler. Ferroelectric properties were primarily controlled by the filler phase amount. Piezoelectric charge coefficients (d33) increased with higher BCZT filler fraction. However, piezoelectric voltage coefficients (g33) slightly decreased (or remained almost similar) due to higher dielectric permittivity of composite samples with higher BCZT content.
The magnetic properties revealed that CF content significantly impacted magnetization but not coercivity. Energy harvesting tests using impulse hammer loading indicated that composites with lower CF content generated up to 20 V of output voltage and approximately 400 μW of power. These findings demonstrate the potential of these composites for next-generation devices and applications
Photodegradation mechanism of Reactive Orange 16 by recyclable green Ag/ZnO
No full textTo determine the mechanism of photodegradation of the textile dye Reactive Orange
16 (RO16), an Ag/ZnO nanocomposite containing 1.5 wt.% of Ag was synthesized
using a green precipitation method from zinc acetate, silver nitrat, ethylen glycol and
chitosan.
Based on XRPD and HRTEM/SAED, the ZnO was obtained in wurzite form with
crystallites of 24 nm, while the formed Ag crystallized in the face-centered-cubic
structure with crystallites of 22 nm. The UV-VIS DRS analysis revealed that the band
gap of Ag/ZnO is redshifted to 3.06 eV, indicating that the Ag surface plasmon
resonance (SPR) enhances the absorption of visible light. The Ag/ZnO completely
degraded RO16 within 105 minutes under simulated solar light with a rate constant
of 0.047(4) min−1. PSD analysis showed that the presence of silver prevented ZnO
agglomeration in suspension and also led to decreasing of the ZnO particles, which
contributed to the better photocatalytic activity of Ag/ZnO compared to ZnO. A
detailed analysis of the mechanism revealed that the activity of the Ag/ZnO
photocatalyst was improved due to two simultaneous mechanisms: excitation by UV
radiation through the Schottky junction and excitation by VIS radiation through the
SPR effect.The reusability, repeatability, and reproducibility of the Ag/ZnO were tested due to
its practical application. This sample showed an improvement in photocatalytic
activity after four cycles due to the enhancement in light absorption and the
decrease in agglomerate concentration. The errors for repeatability and
reproducibility were 2.1 and 5.6 %, respectively.
The Ag/ZnO showed an excellent photocatalytic activity, high repeatability,
reproducibility, and reusability in degrading RO16, which opens the chance of its
future application in wastewater treatment
Norepinephrine-induced intracellular Ca 2+ increase is coupled with astrocytic BK channel activation and capillary response
No full textAstrocytes are abundant glial cells organized in a meshwork in which each cell is in contact with both neuronal and vascular elements. They receive and respond to neuronal signals and modulate synaptic activity and diameter of blood vessels through changes in their intracellular Ca2+. Norepinephrine plays an important role in both of these astrocytic functions; however, it remains unclear whether norepinephrine-induced intracellular Ca2+ increase leads to further cellular adjustments in astrocyte activity. Here, we reveal a causal relationship between norepinephrine-induced intracellular Ca2+ increase, a1-adrenergic receptor activation and activation of large-conductance Ca2+ -dependent potassium ion (BK) channel in cultured rat cortical astrocytes. BK channel activation was abolished by a1-adrenergic receptor blockade, depletion of intracellular Ca2+ stores, or dialysis of astrocytes with a Ca2+ chelator. We further show that this norepinephrine-induced astrocytic Ca2+ -BK channel coupling contributes to a reduction in cortical capillary diameter. The capillary response was prevented by pharmacological silencing of astrocytes or BK channel blockade, whereas the norepinephrine effect was mimicked by direct BK channel activation with an agonist in acute brain slices. In summary, these results elucidate a previously unrecognized cellular response of astrocytes to norepinephrine that is coupled with modulation of capillary diameter and may represent an integral part of the astrocytic communication with neurons and blood vessels.
NEW & NOTEWORTHY This study reveals adjustments of astrocyte activity in response to neurotransmitter norepinephrine. We provide compelling demonstration that norepinephrine-induced intracellular Ca2+ increase is coupled with BK channel activation in cultured cortical astrocytes. Our results further indicate that norepinephrine-induced astrocytic Ca2+ -BK channel signaling participates in modulation of capillary diameter in the cortex. These findings provide better understanding of astrocyte communication with neurons and blood vessels
Influence of biocontrol treatments on morphological parameters of infected cabbage cv. Futoški plants
No full textBlack rot, caused by Xanthomonas campestris pv. campestris (Xcc), threatens the yield and quality of cabbage cv. Futoški and other Brassicaceae crops. Due to economic losses and the harmful effects of chemical pesticides, there is an increasing interest in environmentally friendly biocontrol methods. This study evaluated the effects of four antagonistic Bacillus velezensis strains (P-FC 55, RD-FC 88, R-FC 102, and R-FC 114) on the performance of cabbage cv. Futoški plants infected with Xcc. The effect on growth and physiological responses of cabbage was evaluated under controlled greenhouse conditions during the exposure of plants to four application strategies of antagonistic strains, i.e. seed inoculation, preventive foliar, curative foliar 1 (three days after) and curative foliar 2 (after black rot symptoms appeared), depending on the time of application of the Xcc. Plant physiological response was assessed by measuring chlorophyll and epidermal flavonoid content using a portable Dualex device, and biomass parameters (leaf and stem fresh and dry weight) were recorded at the end of the experiment. The relationships among chlorophyll content, flavonoid content, their ratio (NBI), and various morphological parameters were analyzed using principal component analysis (PCA). Preventive treatments (seed and foliar) with all antagonistic strains induced higher chlorophyll accumulation compared to curative treatments. Plants treated with Xcc showed the highest accumulation of epidermal flavonoids, while the lowest accumulation was observed in control treatments with water and NB. The results suggest that preventive application is the most effective strategy for black rot control and promoting plant health in cabbage cv. Futoški