Vinča Institute of Nuclear Sciences
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Simultaneous measurement and analysis of radon, air ion, and aerosol concentrations under varying air pollution and meteorological conditions
No full textRadon’s radioactive decay is the primary natural source of small air ions in the near-ground layer of the atmosphere. The exhalation of radon from the soil is influenced by local meteorological conditions, while the reduction in small air ion concentrations is primarily associated with the concentration of aerosol pollutants in the air. The goal of this measurement campaign was to investigate the correlations between these factors across different meteorological conditions and pollution levels. To achieve this, measurements were conducted under distinct meteorological and air pollution conditions at two separate sites. Measurements in clean air conditions were carried out during the early autumn in a suburban area of Belgrade, while measurements in late autumn were conducted in the city center, where high levels of air pollution, low temperatures, and high humidity were present. Simultaneous measurements and correlation analyses were performed on radon concentration, air ions, particle size distribution, cumulative mass concentration (particulate matter, PM), relative humidity, pressure, and temperature. The results revealed substantially lower radon concentrations during late autumn, primarily attributable to the absence of nocturnal thermal inversions and the suppression of radon exhalation caused by elevated soil moisture content. Small air ion concentrations were notably lower, resulting from both reduced radon exhalation and high levels of air pollution, characterized by elevated aerosol concentrations, which is reflected in a high number of ultrafine particles. Additionally, a strong negative correlation was observed between air ion concentration and concentration of ultrafine and fine particles (20 to 650 nm). In contrast, radon concentrations exhibited a clear diurnal pattern during the summer, with nocturnal maxima and daytime minima, while radon levels remained consistently low during the winter.International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences : May 26-30, Crete, Greece
Edge modes in nonlinear zig-zag modulated waveguide arrays with zero average modulation
No full textTopological edge states in periodically driven (Floquet) systems have attracted significant interest in recent years, particularly in photonic platforms, where their experimental realization and manipulation are highly controllable [1]. Among the key features of such systems are the so-called π-modes — robust edge-localized states with quasienergies locked at half the driving frequency — which are unique to time-periodically modulated lattices and have no static analog [1-5]. While extensive studies have addressed linear Floquet topological phases, the impact of nonlinearity remains an active area of research with many open questions [1]. In this work, we examine edge π-modes in nonlinear Su-Schrieffer-Heeger (SSH) lattices driven by zero-average time-periodic modulation as shown in Figure 1. Building on prior studies that identified nonlinear Floquet edge solitons bifurcating from linear π-modes in the high-frequency regime [6, 7], we extend the analysis to examine their nonlinear continuation under Kerr-type interactions and explore their behavior across both fast and slow driving regimes. We aim to map the stability properties of the resulting nonlinear π-mode family through detailed Floquet linear stability analysis. In addition, we consider the emergence of topological mode bifurcations induced by nonlinearity, focusing on transitions between distinct families of edge-localized states and the onset of dynamical instabilities. These findings contribute to the broader understanding of nonlinear Floquet topological phases and open pathways for engineering robust edge-localized excitations in photonic systems governed by time-periodic driving.X International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; 25 - 29 August 2025 Belgrade, Serbia
Rapid vs. Conventional Annealing: Impact on Optical Losses in TiN Thin Films
No full textTitanium nitride (TiN) is emerging as a promising alternative to noble metals for plasmonic and photonic applications, offering stability and CMOS compatibility [1,2]. This study investigates the effects of 150 keV Au ion implantation followed by rapid thermal annealing (RTA) and conventional annealing on the optical and metallic properties of sputtered TiN thin films. Ion implantation modifies the dielectric function by introducing damage and smaller crystallites, which reduces the metallic character and optical losses (Figure 1). Post-implantation RTA significantly enhances the metallic response, decreasing plasma frequency and Drude broadening, thus minimizing optical losses. Comparable results are achieved by conventional annealing; however, it requires longer processing time. At 500 °C, conventional annealing leads to the formation of Au nanoparticles, introducing additional absorption due to scattering. Overall, RTA proves to be a more efficient route for tuning the plasmonic performance of TiN films, making it highly suitable for applications in the visible–NIR range where low optical losses and defined metallic behavior are essential.X International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; 25 - 29 August 2025 Belgrade, Serbia
The comparative analysis of electromagnetic shielding efficiency of graphene oxide composites with different silver nanostructures
No full textThe electronic devices and gadgets that emit electromagnetic waves are omnipresent in modern society. They are causing the saturation of the environment with electromagnetic waves that might jeopardize human health [1], emphasizing the need to seek effective electromagnetic shielding materials [2,3]. This study provides a comparative analysis of the electromagnetic interference shielding effectiveness (EMI SE) of graphene oxide (GO) composites with two distinct silver nanostructures: AgNWs and AgNPs. AgNWs were synthesized using the "polyol" method and combined with GO, while AgNPs were directly formed on GO through low-dose gamma irradiation. By applying different microscopy and spectroscopy characterization techniques, the morphological and structural properties of the prepared composites were examined. The EMI SE measurement revealed a superior EMI SE of GO-AgNW composites compared to GO-AgNPs. Composites with higher concentrations of AgNWs exhibit increased total shielding effectiveness and reflective shielding effectiveness (SET values of 0.9, 1.4, and 4.0, and SER values of 0.4, 0.8, and 2 dB for GO-AgNWs 5:5, GO-AgNWs 3:7, and GO-AgNWs 1:9, respectively) (Figure 1.). As the amount of AgNWs in the composites increases, there is a slight rise in the measured SEA values, which increase from 0.4 dB to 1.9 dB concerning the AgNWs content. This difference may be attributed to the structural differences between the Ag nanostructures.X International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; 25 - 29 August 2025 Belgrade, Serbia
Synthesis and characterization of Cu(II)‑meso-HMPAO complex as a model for the development of potential 64Cu radiopharmaceutical
No full textIn this work, Cu(II) complexes with meso‑HMPAO and d,l-HMPAO were synthesized. The structural characterisation of the isolated compounds has been done by single-crystal X-ray diffraction analysis, FTIR, and mass spectroscopy. Redox properties of complexes and binding to deoxyribonucleic acid (DNA) molecule have been analysed in detail by cyclic voltammetry and DFT calculations. The results of cyclic voltammetry fully agree with the data obtained by DFT calculations and indicate that the first electron removal takes place from the metal, while the second electron is removed from the ligand. The formation of the complex leads to the shift in oxidation peaks of the ligand from ‒0.29 V to 0,47 V and from 1.18 V to 1,24 V, indicating that ligand in the complex is much more difficult to oxidize. Electrochemical data confirmed the binding between the complex and DNA molecules through guanine. DFT calculations show that the complex is suitable not only for binding purine and pyrimidine bases through a coordination bond but also for additional hydrogen and CH-π interactions of the bases with the ligand. The fluorescence titration experiments revealed a moderate binding affinity of the [Cu-HMPAO]ClO4 complex to human serum albumin (HSA). Molecular docking revealed that this ligand preferentially binds to drug binding site 3 of HSA. Therefore, the novel compounds could be of great interest for further investigation, considering the potential anticancer activity, and as a model for the development of radiopharmaceutical with 64Cu.This is the peer-reviewed version of the article: Mirković, M., Belaj, F., Perić, M., Stanković, D., Radović, M., Milanović, Z., ... & Mihajlović-Lalić, L. E. (2025). Synthesis and characterization of Cu (II)‑meso-HMPAO complex as a model for the development of potential 64Cu radiopharmaceutical. Journal of Molecular Structure, 1321, 139791. [http://dx.doi.org/10.1016/j.molstruc.2024.139791
Computational insights into the redox properties and electronic structures of [Tc=O]3+ complexes: Implications for 99mTc-radiopharmaceuticals
No full textTechnetium-99m plays a pivotal role in nuclear medicine, offering unique IMAGING capabilities due to its favorable physical and chemical properties. This study investigates the redox behavior and electronic structures of three representative Tc(V) oxo complexes, [TcO(HMPAO)], [TcO(Bicisate)], and [TcO(DMSA)2]-, using computational techniques. Employing relativistic density functional theory with the Zero-Order Regular Approximation (ZORA), we analyze singlet-triplet energy gaps, Gibbs free energy changes, and redox potentials in neutral and acidic environments. The results highlight the significant influence of co-ligands on the electronic stabilization of complexes and their tendencies toward reduction and protonation. The findings also elucidate the role of Jahn-Teller distortions in shaping the redox properties of the studied complexes. Redox potential trends indicate enhanced reducibility in complexes with sulfur-based ligands, impacting their clinical utility. This study provides valuable insights into the design and optimization of technetium-based radiopharmaceuticals, emphasizing their stability and behavior under physiological conditions. © 2025 Elsevier Inc.This is the peer-reviewed version of the article: Perić, M., Milanović, Z., Mirković, M., Radović, M., & Vukadinović, A. (2025). Computational insights into the redox properties and electronic structures of [ Tc= O ] 3+ complexes: Implications for 99mTc-radiopharmaceuticals. Journal of Molecular Graphics and Modelling, 108955. [https://doi.org/10.1016/j.jmgm.2025.108955
High-temperature nanoindentation behavior of single-crystalline titanium: insights from molecular dynamics simulations
No full textTitanium (Ti), a metal with a hexagonal close-packed structure, exhibits outstanding mechanical and thermal properties, making it ideal for applications in extreme environments. Structural integrity at elevated temperatures has been extensively studied through experimental mechanical testing. In recent years, computational modeling has provided critical insights into its plastic deformation mechanisms across different temperatures as a complement to experimental data. In this work, we employ molecular dynamics simulations to investigate the mechanical response of single-crystalline Ti under nanoindentation using a rigid spherical diamond indenter (R = 12 nm) in the 10–900 K range. The empirical interatomic potential for simulating the mechanical response of single-element materials was chosen by considering the generalized stacking fault energy and slip dissociation pathways responsible for stacking fault formation and dislocation activity during mechanical loading. Atomic strain mapping was used to visualize the evolution of plastic deformation beneath the indenter at elevated temperatures. Nanoindentation simulations reveal the development of pile-ups and changes in the surface morphology induced by dislocation motion at different temperatures. The obtained results provide fundamental insights into temperature-driven changes in dislocation dynamics, slip mechanisms, and local hardness, enhancing understanding of Ti’s thermomechanical stability. These findings contribute to the design and optimization of Ti-based materials for high-temperature structural applications.MME SEE 2025 : 6th Metallurgical & Materials Engineering Congress of South-East Europe; 4-7 June 2025; Trebinje, Bosnia and Herzegovina
Early olfactory dysfunction in experimental autoimmune encephalomyelitis reflects transient brain barrier breach and initiation of neuroinflammation in the olfactory bulb
No full textOlfactory dysfunction is increasingly recognized as an early, non-motor manifestation of multiple sclerosis (MS), but the mechanisms underlying its occurrence remain unclear. Using the rat model of experimental autoimmune encephalomyelitis (EAE), we investigated the temporal relationship between olfactory impairment, neuroinflammation, barrier integrity, and adenosine signaling in the olfactory bulb (OB) in the early stage of EAE. The study showed that more than two-thirds of EAE animals exhibited significant deficits in the buried food test as early as 3 days post-immunization (dpi), which preceded the first motor symptoms by several days. Open field test confirmed that these olfactory deficits were not due to impaired locomotion. Transient breach to the OB tissue barrier was demonstrated at 3–5 dpi by increased FITC-dextran penetration and peripheral monocyte/macrophage infiltration into the lateral aspect of the OB. The breach coincided with activation of microglia in the outer nerve layer on the lateral aspect of the OB. Oxidative stress, including elevated malondialdehyde, nitric oxide, and superoxide ion levels along with a depleted antioxidant defense system, indicated a redox imbalance, while a transient increase in neurofilament light chain serum levels at 3 dpi indicated acute neuroaxonal injury and barrier disruption at early stage EAE. At the molecular level, the simultaneous upregulation of CD73 and adenosine A1/A2A receptors along the pial surface and in the olfactory nerve layer suggested enhanced adenosine signaling in early barrier modulation. Spatial mapping of FITC-dextran penetration, peripheral infiltrates, and microglia activation indicated access of immune cells from the subarachnoid space into the OB parenchyma. Overall, these results demonstrate that the OB is a permissive entry zone for autoreactive immune cells in the OB in early stages of EAE, highlighting olfactory and behavioral testing as promising tools for early detection and monitoring of MS
Intracellular effect of synergistic action of N-TiO2 nanoparticles and blue light on HeLa cervical cancer cells: Raman spectroscopic study
No full textUnlike titanium dioxide nanoparticles (TiO2 NPs), nitrogen-doped TiO2 NPs (N- TiO2 NPs) absorb the light in the visible spectrum, thus showing a high potential to be used as photosensitisers in photodynamic therapy (PDT). This promising approach, with its localised effect and minimal side effects, could significantly improve cancer treatment. The shift in absorption towards higher wavelengths, enabled by nitrogen doping, makes N-TiO2 NPs a safer option for PDT for various types of cancer, instilling hope for the future. In this work, we have investigated changes in the structure of biomolecules in HeLa cells treated with N-TiO2 NPs in the dark or combination with blue light (405 nm). To do that, we applied the molecular imaging technique, i.e. Confocal Raman Microscopy (CRM), and acquired spectra and images of HeLa cervical cancer cells subjected to treatment with two concentrations of N-TiO2 NPs (2.5 μg/mL and 7.5 μg/mL) in the dark, and upon blue light illumination. The results are statistically analysed. The most notable changes in lipids and proteins occurred when HeLa cells were treated with a higher concentration of N-TiO2 NPs combined with blue light.ICCBIKG 2025 : 3rd International Conference on Chemo and Bioinformatics, September 25-26, 2025; Kragujevac, Serbia
Unraveling the role of Ni and Co deposition on BiVO4 thin films: Surface chemistry insights into enhanced photoelectrochemical water splitting
No full textBismuth vanadate (BiVO4, BVO) is one of the most promising photoanode materials for photoelectrochemical (PEC) water splitting due to its suitable bandgap, good visible light absorption, and favorable band alignment for oxygen evolution reaction (OER). Cocatalysts are commonly applied to BVO to accelerate surface reaction kinetics, enhance charge extraction, and suppress carrier recombination. In this work, we investigate the effect of Ni- and Co-based cocatalyst deposition on the PEC performance of hydrothermally synthesized BVO thin films. Thin layers of Ni, Co, and their combinations (~3 nm) were deposited using magnetron sputtering, and their influence on OER was evaluated in 0.1 M potassium phosphate buffer (pH = 8). Linear sweep voltammetry revealed significant enhancement in photocurrent density upon cocatalyst deposition. The sample modified with sequential Ni then Co deposition exhibited the highest photocurrent density of 2.43 mA/cm2 at 1.23 V vs RHE, approximately threefold higher than the unmodified BiVO4 film. Furthermore, a cathodic shift of ~0.15 V in onset potential was observed for all cocatalyst-modified samples. Mott-Schottky analysis indicated an order-of-magnitude increase in carrier density and more positive flat band potentials for cocatalyst-modified films. XPS analysis revealed that Co remained on the surface as Co(OH)2, while Ni predominantly migrated into the bulk as metallic Ni when deposited before Co, forming a conductive bridge between the BVO matrix and the surface-active catalytic sites. This spatial configuration facilitates charge separation and enhances OER kinetics. These findings highlight the critical role of cocatalyst composition,‚deposition order, and film architecture in developing efficient and durable BVO -based photoanodes for solar-driven OER.5th International Meeting on Materials Science for Energy Related Applications, September 25-26, 2025, Belgrade