Vinča Institute of Nuclear Sciences
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Effects of silver coated graphite particles on mechanical and electromagnetic shielding properties of an epoxy resin
No full textThe metallization of graphite particles by the deposition of silver particles onto their surfaces was studied. By using a silver conductive dispersion obtained via a modified Tollens process, elemental silver was deposited to the surfaces of the graphite particles. Graphite particles were treated with three different volumes of the silver conductive dispersion. Various analyses were conducted to examine the properties of the particles, including FESEM/EDS, XPS, XRF, and XRD analyses. After characterization, modified graphite particles are used to produce composites based on epoxy resins. Additionally, the polymer characteristics were evaluated through the viscosity determination and torsion dynamic mechanical thermal analysis. The study also explored the relationship between the mechanical properties of the composite and the mass fraction of modified graphite particles, along with the electromagnetic interference shielding efficiency in the X-band. Analysis of the powder particles showed a significant concentration of elemental silver on the particles' surface. The incorporation of these graphite particles enhanced the physical and mechanical properties of the composite. The average attenuation of the wave intensity increases by 21 % with the deposition of silver compared to the graphite sample without silver. The average attenuation of wave intensity for samples with mass ratios of 10, 20, 30, and 40 wt % were recorded at 3.68, 6.04, 7.06, and 8.01 dB, respectively
Photocatalytic degradation of amoxicillin on titanium (IV) oxide modified by copper deposition
No full textEEM2025 - 9th International Congress Engineering, Environment and Materials in Process Industry; 2-4 april 2025; Bijeljina, Republic of Srpska, Bosnia and Herzegovina
Повезаност онкогених микроРНК-10б и микроРНК-21 са величином и локализацијом глиобластома
No full textIntroduction/Objective In glioblastoma, upregulation of oncogenic microRNA-10b (miR-10b) and microRNA-21 (miR-21) is often found. Our study aimed to investigate whether there is a link between miR-10b and miR-21 expression levels and tumor size and tumor localization. Methods The research involved 43 patients diagnosed with glioblastoma. We analyzed the expression levels of miR-10b and miR-21 post-surgery. The data on tumor size and tumor localization were obtained from magnetic resonance imaging. Results The median expression level of miR-10b in patients with tumors < 4 cm was 214.86 (min–max: 2.13–816.89), while in patients with tumors ≥ 4 cm, the median expression level was 92.99 (min–max: 19.24–491.82). The median expression level of miR-21 in patients with tumors < 4 cm was 81.69 (min– max: 11.39–825.43), whereas in patients with tumors ≥ 4 cm, the median expression level was 40.84 (min–max: 2.68–278.98). For both miR-10b and miR-21, a statistically significant difference was found for tumors < 4 cm (p = 0.027 and p = 0.047, respectively) compared to those ≥ 4 cm. There was no statistically significant difference in the expression levels of miR-10b (p = 0.675) and miR-21 (p = 0.183) in relation to tumor localization. Conclusion Glioblastomas smaller than 4 cm have statistically significantly higher expression levels of miR-10b and miR-21 compared to glioblastomas equal to or larger than 4 cm. Although this result is unexpected, it could mean that miR expression levels dynamically change after surgery and according to the altered microenvironment. © 2025, Serbia Medical Society. All rights reserved.Увод/Циљ Код глиобластома често се уочава појачана експресија онкогених микроРНК-10б и микроРНК-21. Циљ наше студије је био да истражи да ли постоји повезаност између нивоа експресије микроРНK-10б/21 и величине и локализације глиобластома. Методе У истраживању су учествовала 43 болесника са дијагнозом глиобластома. Анализирали смо нивое експресије микроРНK-10б/21 након оперативног лечења. Подаци о величини и локализацији глиобластома добијени на основу налаза магнетне резонанце. Резултати Медијана експресије микроРНК-10б код болесника са туморима < 4 cm износила је 214,86 (опсег: 2,13–816,89), док је код болесника са туморима ≥ 4 cm била 92,99 (опсег: 19,24–491,82). Медијана експресије микроРНК-21 код болесника са туморима < 4 cm била је 81,69 (опсег: 11,39–825,43), док је код болесника са туморима ≥ 4 cm била 40,84 (опсег: 2,68–278,98). За микроРНК-10б и за микроРНК-21 нађена је статистички значајна разлика за туморе < 4 cm (p = 0,027, односно p = 0,047) у поређењу са туморима ≥ 4 cm. Није било статистички значајне разлике у нивоима експресије микроРНК-10б (p = 0,675) и микроРНК-21 (p = 0,183) у односу на локализацију тумора. Закључак Глиобластоми мањи од 4 cm имају статистички значајно веће нивое експресије микроРНК-10б и микроРНК-21 у поређењу са глиобластомима једнаким или већим од 4 cm. Иако је овај резултат неочекиван, он може упућивати на то да се нивои експресије микро РНК динамички мењају након операције и у складу са измењеним микроокружењем глиобластома
Compact Topological Edge States in Flux-Dressed Graphene-Like Photonic Lattices
No full textWe report the existence of compact topological edge states on flux-dressed photonic graphene ribbons [1]. Robust localization is achieved through a synergy of Aharonov- Bohm caging and topological protection mechanisms. The topological nontriviality of the compact edge states predicted by theoretical derivations is confirmed by experimental estimation of an integer Zak phase obtained from the mean chiral displacement. Experiments are performed using direct femtosecond laser writing of a graphene ribbon photonic lattice having 0 or synthetic magnetic flus. Mode stability is demonstrated by its exceptional localization and resilience to fabrication tolerances and input phase variations. Demonstration of the compact edge modes opens the door to exploitation of the synergy between flat-band physics and topology in secure information transfer and high-temperature superconductivity.18th Photonics Workshop : International conference; March 16-20, 2025; Kopaonik, Serbia
Synthesis, characterization and biocompatibility assesement of Au-tea tree particles
No full textObjectives: To synthesize and characterize gold nanoparticles (AuNPs) using tea tree essential oil and evaluate their cytotoxicity and potential bioactive properties. To investigate the synthesis of AuNPs via the "ouzo effect" using tea tree oil, characterize their structure and morphology, and assess their cytotoxicity and antioxidant activity for potential biomedical applications. Methods: Gold nanoparticles (AuNPs) were synthesized using aqua regia via the "ouzo effect" with an ethanolic solution of tea tree essential oil. The resulting nanoparticles were characterized by X- ray diffraction (XRD) to confirm their crystalline gold structure. Field-emission scanning electron microscopy (FESEM) was used to analyze particle morphology, revealing spherical and agglomerated structures, while transmission electron microscopy (TEM) showed a thin organic coating of essential oil around the nanoparticles. Cytotoxicity was evaluated using the XTT cell viability assay on normal human lung fibroblast cell line MRC-5, and preliminary antioxidant activity assays were performed. Results: Cytotoxicity testing showed that AuNPs at concentrations up to 500 μg/mL had no significant effect on cell viability. At 1000 μg/mL, there was a slight but significant increase in cell survival (p < 0.05). However, exposure to 2000 μg/mL for 24 hours resulted in a significant reduction in viable cells (p < 0.01), indicating cytotoxicity at the highest tested concentration. Conclusions: The synthesized AuNPs exhibited biocompatibility at lower concentrations and demonstrated potential bioactive properties. Given their promising characteristics, these nanoparticles could be explored for anti-inflammatory applications, such as mouthwashes or gels for oral mucosal inflammation.29th BaSS Congress of the Balkan Stomatological Society; Belgrade, April 24 - 26, 2025
Predicting the Fate of Bisphenol A During Electrochemical Oxidation: A Simple Semiempirical Method Based on the Concentration Profile of Hydroxyl Radicals
No full textThe efficiency of electrochemical advanced oxidation processes (EAOPs) is fundamentally governed by hydroxyl-radical (•OH) generation. While direct experimental measurements of these transient species remain complex and impractical, robust computational methods for predicting their temporal profiles are notably scarce. This work presents a semi-empirical methodology based on H2O2 measuring experiments that enables indirect •OH quantification. We employed a recently developed carbon-based electrode and the priority pollutant bisphenol A (BPA) as the model system. The system achieved 92.3% BPA degradation with 84% mineralization efficiency during 5-h electrooxidation at 15 mA/cm2. Gas chromatography/mass spectrometry (GC/MS) was used for tracking BPA and detection of intermediates. On this basis, we developed a computational model that successfully predicts temporal concentration profiles of all reactive species interacting with •OH, along with degradation kinetics across current densities (10–20 mA/cm2). By incorporating predictions from the Toxicity Estimation Software Tool (T.E.S.T.), the developed model accurately simulates time-dependent evolution of relative toxicity throughout the treatment process. The presented approach has a general character and requires rather simple experimental input to predict and optimize degradation outcome in terms of input concentration, degradation time, current density, and final toxicity. Further modifications of the model would enable widening to other EAOPs systems. © 2025 by the authors
Samarium-Doped PbO2 Electrocatalysts for Environmental and Energy Applications: Theoretical Insight into the Mechanisms of Action Underlying Their Carbendazim Degradation and OER Properties
No full textThis study presents the fabrication of a samarium-doped Ti/Sb-SnO2/PbO2 electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO2/Sm-PbO2 electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO2/PbO2 electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO2/Sm-PbO2 electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na2SO4 with an applied current density of 10 mA/cm2 in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. © 2025 by the authors
Evaluation of the Impact of Selected Metallic Contaminants on Wild Rutilus rutilus Through Integrated Antioxidant Biomarker Responses
No full textThe application of biomarkers is often used to better understand the assessment of the toxicity in aquatic organisms within their natural environment. To this end, we examined the gills and liver of roach (Rutilus rutilus) to measure changes in the activity of the antioxidant enzymes superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione reductase and the phase II biotransformation enzyme glutathione-S-transferase (GST), as well as changes in the concentration of lipid peroxides (LPOs). Roach were collected at two localities, Veliko Ratno ostrvo and Višnjica (VIS), on the Danube River, where the concentrations of dissolved metals (Cu, Cd, Zn, Fe, Mn, Hg, Ni, As, Pb) in both fish tissues were quantified. This paper describes the integrated reaction of antioxidant enzymes and LPO levels of roach from two sampling localities in the Danube River. Principal component analysis revealed obvious differences of the antioxidant biomarkers investigated between tissues and localities, while integrated biomarker response showed that the liver of the VIS locality had the stronger antioxidant biomarker response. Despite the concordant hypothesized antioxidant induction at the VIS locality in both tissues studied, the effects as a sign of contaminant exposure appear to be mediated in part by suppression of the antioxidant system, with CAT and GST as potential candidate tissue toxicity biomarkers of contaminants. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025
Introductory Chapter: MEMS and Emerging Technologies – Converging Innovations Shaping the Future
No full textTechnological advancements over the past few decades have dramatically transformed industries and the way we interact with the world. Among the most significant innovations are microelectromechanical systems (MEMS) and the array of emerging technologies that are reshaping industries, economies, and societies. MEMS, which integrate tiny mechanical components with electronics, serve as the foundation for advancements in sectors such as health care, automotive, environmental monitoring, consumer electronics, and robotics. Their ability to sense, actuate, and communicate within compact, power-efficient devices has made them indispensable. However, the true potential of MEMS lies not just in their individual applications but in their convergence with emerging technologies like artificial intelligence (AI), quantum computing, biotechnology, neurotechnology, and the metaverse, creating new possibilities and unlocking unprecedented potential. [from Introduction
Influence of ascorbate on anti-HeLa effect of Fe(III)-heteropolyanion: concentration ratio 1:5
No full textThis study aims to assess the the effect of L(+)-ascorbic acid sodium salt (ascorbate) on the cytotoxic activity of Fe(III)-substituted monolacunary Wells-Dawson polyoxometalate (Fe-WD), K7[FeIII(α2- P2W17O61)(H2O)] (Fe-WD/ascorbate ratio 1:5) against cervical carcinoma HeLa cells. HeLa cells were treated in vitro with Fe-WD, ascorbate, and Fe-WD/ascorbate mixtures (concentration ratio 1:5) for 48 and 72 hours at 37 °C. Single and simultaneous treatments with Fe-WD/ascorbate resulted in concentration- and time-dependent HeLa cell cytotoxicity with different potencies. Fe-WD showed remarkably more potent cytotoxic action compared with ascorbate, inducing approximately 10-15 times lower IC50 values for both exposure times. The results obtained for the simultaneous exposure to Fe-WD/ascorbate mixtures (1:5) demonstrated that the presence of ascorbate does not significantly affect Fe-WD-induced anti-HeLa action. This effect might be associated with the fact that the concentration ratio of Fe-WD and ascorbate 1:5 causes ascorbate consumption due to its autoxidation in the presence of Fe(III) ionsInternational Conference “Annual conference on Challenges of Contemporary Higher Education” : February 2nd-7th, 2025, Kopaonik