Vinča Institute of Nuclear Sciences
Recent publications
Carbon quantum dots (CQDs) are well known as a promising therapeutic agent due to their excellent pro-oxidant, antioxidant, antibacterial and anticancer properties under visible light irradiation. This material is easy to produce by several bottom-up or top-down methods. In this study, we used citric acid as starting precursor to synthesize aqueous carbon quantum dots dispersion by pyrolysis at 210 o C. Atomic force microscopy and XPS analyses revealed that CQDs synthesized are quasi-spherical with typical diameter of 9 nm and lots of C-O and C = O functional groups distributed over the basal plane and edges of the dots. Here, we investigated the antiviral properties of CQDs against cytomegalovirus (CMV). The pre-treatment with CQDs upregulates interferon-stimulated genes (ISG), resulting in better virus control. Cellular defence against cytomegalovirus of CQDs pre-treated cells is increased in a dose-dependent manner. Our results reveal high biocompatibility and potent in vitro antiviral properties of CQDs.
Crystal structure prediction has been performed via the global exploration of the energy landscape of lanthanum oxyiodide (LaOI), using simulated annealing and involving over one million local optimizations. Afterwards, the most promising structure candidates among the minima found were subjected to local optimizations on ab initio level. Density functional theory (DFT) calculations were performed, using the GGA‐PBE functional, together with the hybrid HSE06 exchange‐correlation functional. Seven most relevant low‐energy minima were found after the final ab initio relaxation. The global minimum found corresponds to the α‐LaOI tetragonal structure in agreement with previous experimental and theoretical reports. The prediction of the additional β‐, γ‐, δ‐, ε‐, ζ‐, and η‐LaOI modifications demonstrate the rich diversity of local cation‐anion coordinations and structure types ranging from cubic and tetragonal, over rhombohedral and orthorhombic to monoclinic symmetry. Moreover, there are many previous experimental reports on related structures in the lanthanide oxyfluorides, which might guide possible future syntheses of LaOI‐modifications. A successful synthesis of these novel LaOI materials could have multiple technological applications ranging from nano‐ and bio‐materials to medicine, solid oxide fuel cells and photocatalytic materials.
Background: Disturbed heart dynamics in depression seriously increases mortality risk. Heart rate variability (HRV) is a rich source of information for studying this dynamics. This paper is a meta-analytic review with methodological commentary of the application of nonlinear analysis of HRV and its possibility to address cardiovascular diseases in depression. Objective: This paper aimed to appeal for the introduction of cardiological screening to patients with depression, because it is still far from established practice. The other (main) objective of the paper was to show that nonlinear methods in HRV analysis give better results than standard ones. Methods: We systematically searched on the web for papers on nonlinear analyses of HRV in depression, in line with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 framework recommendations. We scrutinized the chosen publications and performed random-effects meta-analysis, using the esci module in jamovi software where standardized effect sizes (ESs) are corrected to yield the proof of the practical utility of their results. Results: In all, 26 publications on the connection of nonlinear HRV measures and depression meeting our inclusion criteria were selected, examining a total of 1537 patients diagnosed with depression and 1041 healthy controls (N=2578). The overall ES (unbiased) was 1.03 (95% CI 0.703-1.35; diamond ratio 3.60). We performed 3 more meta-analytic comparisons, demonstrating the overall effectiveness of 3 groups of nonlinear analysis: detrended fluctuation analysis (overall ES 0.364, 95% CI 0.237-0.491), entropy-based measures (overall ES 1.05, 95% CI 0.572-1.52), and all other nonlinear measures (overall ES 0.702, 95% CI 0.422-0.982). The effectiveness of the applied methods of electrocardiogram analysis was compared and discussed in the light of detection and prevention of depression-related cardiovascular risk. Conclusions: We compared the ESs of nonlinear and conventional time and spectral methods (found in the literature) and demonstrated that those of the former are larger, which recommends their use for the early screening of cardiovascular abnormalities in patients with depression to prevent possible deleterious events.
Although sample preparation, as an unavoidable step of the analytical process should be simple, it is very often identified as a bottleneck. Simplicity of sample preparation based on cost-effective and non-hazardous materials is mandatory for any sustainable and environmental friendly approach. Aqueous biphasic systems (ABS), based on functionalized ionic liquids (FILs) are acceptable alternatives to classical extraction procedures, due to the replacement of organic solvent with diluted aqueous ionic liquids. In this work, two water soluble FILs based on 2-mercaptobenzothiazolate anion, [mbt]: 1-butyl-3-methylimidazolium [mbt] ([bmim][mbt]) and 1-ethyl-3-methylimidazolium [mbt] ([emim][mbt]), were designed and synthesized in order to selectively extract Cd(II) and Pb(II) from the river sediment. It was found that [mbt]– anion acts as the ligand and forms complexes with Cd(II) and Pb(II) which are responsible for their efficient extraction, while cation is more responsible for the formation of ABS. Partition coefficients of 408 and 180 for Cd(II) and Pb(II), respectively, were obtained using ABS based on [bmim][mbt]. Direct extraction of Cd(II) and Pb(II) from the river sediment has been investigated and obtained optimal conditions are: 60 min direct contact of the aqueous solution of [bmim][mbt] and the sediment sample at 90 °C, followed by formation of ABS upon addition of potassium citrate. Using AGRE and AGREEprep tools greenness of the proposed method for direct extraction of Cd(II) and Pb(II) from the sediment are calculated.Obtained values of 0.69 and 0.71 for Cd(II) and Pb(II) extraction, respectively, showed a high level of the greenness of the proposed method.
Deoxyribonucleic acid (DNA) is found in all prokaryotic and eukaryotic cells and many viruses. This complex molecular structure is certainly one of the most interesting molecules. Interest in its structure and dynamics is primarily due to the important role that this molecule plays in life processes. The molecule was first identified in the 1860s by the Swiss chemist Johann Friedrich Miescher. He discovered a substance that had unexpected properties, different from those of the other proteins he had been familiar with. He did not know he had discovered the molecular basis of life, which he called nuclein.
Microtubules (MTs) were discovered by biologists more than 50 years ago. This great breakthrough was made whilst trying to isolate, purify, and characterize the colchicine-binding protein, as explained in a review paper (Borisy et al. in Nat Rev Mol Cell Bio 17:322, 2016 [1]). There are two kinds of cells, eukaryotic and prokaryotic ones. Eukaryotes are usually larger and much more sophisticated than prokaryotic cells. Plant and animal cells are eukaryotic, whilst bacterial cells are prokaryotic.
The arsenite-humic acid binding process was investigated using Isothermal Titration Calorimetry (ITC), Dynamic Light Scattering and Laser Doppler Electrophoresis techniques. The ITC data were successfully (R2 = 0.996-0.936) interpreted by applying the MNIS model, enabling thermodynamic parameters to be determined. The MNIS model was adjusted to the arsenite-HA binding process assuming that hydrogen bonding is the dominant type of interaction in the system. Negative enthalpy change values indicated the arsenite-HAs binding as an exothermic process. Negative ΔG values (-(26.83-27.00) kJ mol-1) pointed out to spontaneous binding reaction, leading to the formation of the arsenite-HA complexes. The binding constant values ((7.57-5.02) 105 M-1) clearly demonstrate pronounced binding affinity. As ΔS values are obviously positive but close to zero, and ΔH>ΔS, the reaction can be considered enthalpy driven. Reaction heats and ΔH values (-(18.96-15.64) kJ mol-1) confirmed hydrogen bonds as the most ascendant interaction type in the arsenite-HA complex. Negative zeta potential values (-45 to -20 mV) had shown that arsenite-HA aggregates remained negatively charged in the whole molar charge ratio range. The HAs' aggregate size change is evident but not particularly pronounced (Zav = 50-180 nm). It can be speculated that aggregation during the titration process is not expressive due to repulsive forces between negatively charged arsenite-HA particles. Thermodynamic and reaction parameters clearly indicated that arsenite-HA complexes are formed at common soil pH values, confirming the possible influence of humic acids on increased As mobility and its reduced bioavailability.
The study examines the effect of neutron and gamma radiation on commercial gas surge arresters. The research is of experimental-theoretical nature. The experimental part of the research was performed un-der well-controlled laboratory conditions. The combined measurement uncertainty was about 5%. The experimental system is specially designed for the observed problem and has certain original solutions. The test procedure was fully automated and had software support in the experiment management and also for data collection and statistical processing. The obtained results show that neutron and gamma ra-diation improves the functional characteristics of gas surge arresters with a memory effect. The obtained results are explained in accordance with the theory of interaction of neutron and gamma fields with ma-terial and with the theory of electric discharge in gases. The results presented in this study are important for the design of surge protection in systems that can be found in the field of neutron and gamma radia-tion because they can achieve a positive synergistic effect of protection in hybrid schemes with other components for surge protection whose characteristics spoil this radiation.
By introducing standard physical methods for the detection of irradiated herbs and spices by photostimulated luminescence and thermoluminescence, measurements of different irradiated samples have been undertaken and an analysis of the results has been done. Since luminescence may occur under natural and artificial light stimulation on which herbs and spices may be exposed during storage, leading to false-negative results and disabling their proper identification, studied samples have been kept under different light conditions for different periods. The optical bleaching of the photostimulated luminescence and thermoluminescence signal has been detected in all cases. The strong influence of light, natural and artificial, on the photostimulated luminescence signal has been determined.
Cymbopogon martinii is an aromatic crop cultivated for the production of its essential oil (EO) which has different applications. Bearing in mind that C. martinii EO (CMEO) has already been proved for high antibacterial potential the aim of this study was to formulate stable CMEO nanoemulsions, being capable to combat Enterococcus faecalis biofilm, especially within infected tooth’s root canal. Ten emulsions with variable CMEO content (2.5–10 % v/v) and Tween 80 (T80, 2.5–15 % v/v) were formulated (designated as ECMEO:T80) and screened for volume-weighted mean diameter (D4,3) and stability, using dynamic light scattering measurements. Chemical composition of stable nanoemulsions was monitored by UV–VIS and FTIR, while their antibacterial activity was estimated in microdilution assay. Antibiofilm properties of selected nanoemulsions were tested in vitro (cristal violet assay) and ex vivo (within root canals of the extracted teeth). Results showed that formulations containing 10 % of T80 and CMEO volume ≤ 6 %, as well as those having constant 2.5 % of CMEO and variable T80 volume (≤ 10%), namely E2.5:2.5, E2.5:5, E2.5:7.5, E2.5:10, E4:10, and E6:10, were stable and nanosized (D4,3 <100 nm). FTIR and UV–VIS analyses confirmed successful encapsulation of the CMEO by T80 and showed that nanoemulsification did not affect CMEO composition. Evaluation of antibacterial potential showed that the most efficient were E6:10, E2.5:2.5 and E4:10 (MIC values 0.37–1.97 mg mL⁻¹). Analysis of dependency of determined MICs on mean diameter and CMEO volume showed that antibacterial potential increased with both parameters. E6:10, E2.5:2.5 and E4:10 also reduced in vitro biofilm (inhibitory range 17.6–58.4 %), as well as intracanal biofilm (reduction ~2Log CFU). Presented results suggest E6:10, E4:10 and E2.5:2.5 as the good candidates for further research.
Σ3{112} grain boundary (GB) is known to exhibit plastic slip in bcc metals, which overall contributes to the good ductility and toughness of such metals as iron, matrix element for the steels applied in nuclear industry. During nuclear operation, the neutron irradiation causes formation of point defects and their clusters which lead to the non-equilibrium mass transport and agglomeration of nanoscale defects inside grains and near the grain boundaries. Due to the effect of chemical segregation, GBs can encounter sessile obstacles preventing the GB plastic slip. Understanding the influence of the irradiation defects segregated at the grain boundaries is important for the development of structural steels for nuclear fusion and fission applications. The present paper studies the influence of the irradiation defects, such as Cr precipitates, He bubbles and voids on the plastic slip of the GB interface. The studied defects are found to act as strong obstacles to the glide of the elementary disconnections responsible for the shear-coupled GB migration. The interaction between a single elementary disconnection and a series of them provided by a source has been studied. As a result of the interaction with impenetrable defects the formation of residual defects such as loops is observed.
This work represents a contribution to modelling nonlinear dynamics of microtubules, the basic components of the eukaryotic cytoskeleton. Their dynamics can be explained in terms of kink and antikink solitary waves. Special attention was paid to the stability of solitonic solutions of differential equations describing the dynamics of microtubules. It is shown that subsonic solitons are stable, while supersonic ones are not.
Special high-protein foods suitable for diabetics must be treated to ensure the complete absence of microorganisms and bacteria. It is also important to achieve that this treatment does not change the nutritional value of the product. Among the new decontamination technologies, low-energy electron-beam treatment has proven to be an effective technique for inactivating bacteria with minimal impact on food quality. The paper aims to analyze the influence of low-energy electron-beam irradiation on the microbiological properties and nutritional value of high-protein foods.
Nanopowders of up-conversion SrGd2O4 orthorhombic (Pnma) phase co-doped with different Yb³⁺ (1, 2.5 and 5 at%) and constant Er³⁺ (0.5 at%) ions were successfully prepared via sol-gel assisted combustion. Rietveld refinement indicated unit cell lattice parameters increase with Yb³⁺ and Er³⁺ ions doping. Scanning transmission electron microscopy with corresponding energy-dispersive X-ray spectroscopy revealed that obtained powders are composed of agglomerated nanoparticles that have a uniform distribution of all constituting elements. Photoluminescence measurements implied intensification of the up-conversion (UC) emission in the visible part of spectrum with the increase of Yb³⁺ content, which is followed by a significant change in the green to red ratio. Two-photon UC processes are established as a result of Er³⁺ f-f electronic transitions: green emission at 523 and 551 nm (²H11/2, ⁴S3/2 → ⁴I15/2) as well as a red emission at 661 nm (⁴F9/2 → ⁴I15/2). The highest value of absolute quantum yield of 0.055% is determined for SrGd2O4 nanoparticles doped with 0.5 at% of Er³⁺ and co-doped with 5 at% of Yb³⁺ (λexc = 976 nm, power density 200 W/cm²).
The study discusses the validity of the law of similarity for the impulse breakdown of gases at low pressure and small inter-electrode distances. The research has been done theoretically, experimentally and numerically. The experiments were conducted under well-controlled laboratory conditions. The combined measurement uncertainty was less than 5%. The experiments were carried out with gases SF6, N2 and He. The electrodes were made of copper, but also of metals with different values of the work function. The obtained results are presented through the impulse characteristics for similar systems. Such a presentation only provided qualitative information. In order to obtain quantitative information, a modified Wilcoxon Rank Sum Test (U-test) was performed. The obtained results show that the law of similarity is valid for the DC breakdown of gases, but it is not valid for the impulse breakdown of gases. It can be concluded that the law of similarity is inapplicable for the design of gas-insulated systems under low pressure at small values of the inter-electrode distance.
Maize is an important staple crop and a significant source of various nutrients. We aimed to determine the macronutrients, antioxidants, and essential elements in maize genotypes (white, yellow, and red kernel) using three different fertilizers, which could be used as a basis to increase the nutrient density of maize. The fertilizer treatments used bio- and organic fertilizers as a sustainable approach, urea, as a commonly used mineral fertilizer, and the control (no fertilization). We evaluated the yield, concentration of macronutrient (protein, oil, and starch), nonenzymatic antioxidants (phenolics, yellow pigment, total glutathione (GSH), and phytic phosphorus), and reduction capacity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, as well as essential elements that are commonly deficient in the diet (Mg, Ca, Fe, Mn, Zn, Cu, and S) and their relationships with phytic acid. The genotype expressed the strongest effect on the variability of grain yield and the analyzed grain constituents. The red-kernel hybrid showed the greatest accumulation of protein, oil, phenolics, and essential elements (Ca, Fe, Cu, and S) than a yellow and white hybrid, especially in the biofertilizer treatment. The yellow kernel had the highest concentrations of yellow pigment, GSH, phytic phosphorous, Mg, Mn, and Zn (19.61 µg g−1, 1,134 nmol g−1, 2.63 mg g−1, 1,963 µg g−1, 11.7 µg g−1, and 33.9 µg g−1, respectively). The white kernel had a greater starch concentration (2.5% higher than that in the red hybrid) and the potential bioavailability of essential metals, particularly under no fertilization. This supports the significance of white maize as a staple food in many traditional diets across the world. Urea was important for the enhancement of the antioxidant status (with 88.0% reduction capacity for the DPPH radical) and increased potential Zn bioavailability in the maize kernels (13.3% higher than that in the biofertilizer treatment). This study underlines the differences in the yield potential and chemical composition of red, yellow, and white-kernel maize and their importance as a necessary part of a sustainable human diet. This information can help determine the most appropriate genotype based on the antioxidants and/or essential elements targeted for kernel improvement.
Selective cytotoxicity of ZnO nanoparticles among different cell types and cancer and non-cancerous cells has been demonstrated earlier. In the view of anticancer potential of ZnO nanoparticles and their presence in numerous industrial products, it is of great importance to carefully evaluate their effects and mechanisms of action in both cancerous and healthy cells. In this paper, the effects of ZnO nanoparticles on cancerous HeLa and non-cancerous MRC-5 cells are investigated by studying the changes in the vibrational properties of the cells using Raman spectroscopy. Both types of cells were incubated with ZnO nanoparticles of average size 40 nm in the doses from the range 10 - 40 µg/ml for the period of 48 hours, after which Raman spectra were collected. Raman modes’ intensity ratios I1659/I1444, I2855/I2933 and I1337/I1305 were determined as spectral markers of the cytotoxic effect of ZnO in both cell types. Non-negative principal component analysis was used instead of standard one for analysis and detection of spectral features characteristic for nanoparticle-treated cells. The first several non-negative loading vectors obtained in this analysis coincided remarkably well with the Raman spectra of particular biomolecules, showing increase of lipid and decrease of nucleic acids and protein content. Our study pointed out that Raman spectral markers of lipid unsaturation, especially I1270/I1300, are relevant for tracing the cytotoxic effect of ZnO nanoparticles on both cancerous and non-cancerous cells. The change of these spectral markers is correlated to the dose of applied nanoparticles and to the degree of cellular damage. Furthermore, great similarity of spectral features of increasing lipids to spectral features of phosphatidylserine, one of the main apoptotic markers, was recognized in treated cells. Finally, the results strongly indicated that the saturation degree of lipids, presented in the cells, plays an important role in the interaction of cells with nanoparticles.
Considering the urgency of finding a cure for vicious diseases such as tumors, we have synthesized and characterized a small series of new copper(ii) complexes with biologically important ligands such as acylpyruvate. In addition to this, we used another four copper(ii) complexes, with ligands of the same type to examine the antitumor potential. The antitumor potential of the copper(ii) complexes was examined on three tumor cell lines and one normal human cell line using the MTT assay. All seven tested complexes showed very good cytotoxic effects. Two copper complexes that showed the best antitumor potential were selected for further testing that showed the best potential for potential application in the future. The mechanism of activity of these complexes was examined in detail using tests such as cell cycle, ROS level, oxidative DNA damage, and proteins related to hypoxia analysis. In addition, we examined the binding abilities of these complexes with biomolecules (Guo, Ino, 5'-GMP, BSA, and DNA). The results showed that the tested compounds bind strongly to DNA molecules through intercalation. Also, it has been shown that the tested compounds adequately bind to the BSA molecule, which indicates an even greater potential for some future application of these compounds in clinical practice.
To determine the nature and origin of the unconsolidated bottom sediments, as well as to demonstrate and quantify the presence of Presumably Contaminating Elements (PCE) in the Serbian Danube River, as a novelty, the mass fractions on nine major elements as oxides—SiO2, TiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O, and K2O, as well as Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Sb, Cs, Ba, La, Hf, Ta, W, Th, and U were determined by Instrumental Neutron Activation Analysis (INAA) in 13 sediment samples collected between Belgrade and Iron Gate 2 dam. INAA was chosen for its ability to perform elemental analysis without any preliminary sample treatment that could introduce systematic errors. The distribution of major elements was relatively uniform, with the sampling locations having less influence. Concerning the trace elements, excepting the PCE Cr, Ni, Cu, Zn, As, and Sb, their distributions presented the same remarkable similarity to the Upper Continental Crust (UCC), North American Shale Composite (NASC), Average Bottom Load (ABL), and Average Dobrogea Loess (AVL), and were in good concordance with the location of the Serbian Danube River in the Pannonian Plain. In the case of considered PCE, both Enrichment Factor and Pollution Load Index showed values higher than the pollution threshold, which pointed towards a significant anthropogenic contamination, and rising concern to what extent the water quality and biota could be affected.
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501 members
Djurdje Cvijović
  • Department of Physics
Jelena Nikolic
  • Department of Radiation and Environmental Protection
Branislav Nastasijevic
  • Lab of Physical Chemistry 050
Jelena Belosevic-Cavor
  • Laboratory for nuclear and plasma physics
Mike Petrovica Alasa 12-14, Vinca, 11000, Belgrade, Serbia
Head of institution
Milica Marceta Kaninski