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Setting Time of Alkali-Activated Binders Exposed to Co-60 Gamma Radiation
No full textAn investigation of the effect of gamma radiation was carried out on the setting time of alkali-activated binder paste. Mechanically activated coal fly ash (FA), ground granulated blast furnace slag (BFS), and their 1:1 mass mixture (MIX) were activated by water glass with a module of 1.5. Fresh paste was cast into molds and exposed to Co-60 gamma radiation, at a dose rate of 9.62–9.53 Gy/h, until the final setting. The initial and final setting times were determined by measuring the penetration of the Vicat needle at regular intervals. The initial setting times were 1 h 3 min for BFS, 1 h 55 min for MIX, and 3 h 28 min for FA. The final setting times were 1 h 10 min for BFS, 2 h 13 min for MIX, and 4 h 1 min for FA. The received doses were 8.02 Gy for BFS, 17.54 Gy for MIX, and 34.14 Gy for FA. Exposure to gamma radiation resulted in a shorter initial setting time for BFS, a shorter final setting time for FA, and results with an insufficiently visible impact on MIX. For dose rates in the 9–10 Gy/h range, the irradiation by Co-60 gamma rays during setting did not lead to flash, nor did it delay the setting of alkali-activated binder pastes
Analysis of Biomolecular Changes in HeLa Cervical Cancer Cell Line Induced by Interaction with [Pd(dach)Cl2]
No full textTransition metal complexes have been used in medicine for several decades, but their intracellular effects are not yet fully elucidated. Therefore, in this study, we investigate biomolecular changes induced by a palladium(II) complex in cervical carcinoma (HeLa) cells as a model to study the subtle changes caused by transition metal ions ingested by the cells. The impact of dichloro(1,2-diaminocyclohexane)palladium(II), [Pd(dach)Cl2], was studied by synchrotron radiation-based Fourier transform infrared (SR FTIR) spectroscopy, a powerful tool for studying alterations in cellular components’ biochemical composition and biomolecular secondary structure on a single-cell level. A spectral analysis, complemented by statistics, revealed that the Pd(II) complex considerably affected all major types of macromolecules in HeLa cells and induced structural changes in proteins through an increased formation of cross-β-sheets and causes structural rearrangement in deoxyribonucleic acid (DNA) through potential chromosome fragmentation. Although a certain level of lipid peroxidation was detectable by SR FTIR spectroscopy and confirmed by an analysis of cellular lipids by matrix-assisted laser desorption and ionisation time-of-flight mass spectrometry, the oxidative stress is not a significant mechanism by which Pd(II) expresses the effect on the HeLa cell
From biofilms to biocatalysts: Innovations in plastic biodegradation for environmental sustainability
No full textThe increase in plastic waste has evolved into a severe environmental crisis, which requires innovative recycling technologies to repurpose used plastic with adequate environmental protection. This review highlights the urgent need for innovative approaches to the treatment and degradation of post-use plastics. It investigates the promising role of biofilms in the biodegradation of polymers, especially for polymers such as polyethylene terephthalate (PET), polyurethane (PU), and polyethylene (PE). By examining biofilms, researchers can determine key enzymes involved in polymer degradation and improve their efficiency through genetic engineering. In addition, the review explores in detail the structure and development of biofilms on polymeric surfaces, elucidating the role of specific microbial strains necessary for biofilm formation and maintenance. Techniques for identifying enzymes within biofilms and improving their degradation ability are also discussed. The review concludes with recent discoveries in enzyme isolation and the key role of biofilms in the degradation and recycling of major plastic pollutants such as PET, PU, and PE. These findings highlight the potential of biofilm-derived enzymes to promote sustainable polymer recycling. © 2025 Elsevier Lt
Bioinformatic Selection of Mannose-Specific Lectins from Allium genus as SARS-CoV-2 Inhibitors Analysing Protein–Protein Interaction
No full textMannose-specific lectins are carbohydrate-binding proteins known for their antiviral potential. This study uses a bioinformatic approach to investigate the possibility of lectins from Allium sativum (garlic) and Allium ursinum (wild garlic) as inhibitors of SARS-CoV-2 entry. The information spectrum method (ISM) identified key interaction frequencies between the SARS-CoV-2 spike protein and these lectins, explicitly targeting the receptor-binding domain (RBD) and glycosylated asparagine residues, including N234. Lectins from Allium species showed a high affinity for oligomannose-type glycans on the spike protein, potentially blocking virus entry by preventing the spike-ACE2 receptor interaction. We propose that Allium lectins are promising candidates for further experimental validation as SARS-CoV-2 inhibitors, offering potential therapeutic applications in managing viral infections
Effect of the transition metal segregation on the properties of (Hf,Ti,Zr)B2–(Hf,Ti,Zr)C Dual Phase Ceramics
No full textDual phase mid entropy ceramics are attractive due to potential synergistic effects of the constituents on mechanical properties and thermal stability. The co-synthesis method was used to obtain boride and carbide constituents by boro/carbothermal reduction of mixtures of oxides and appropriate amounts of carbon black and B4C. Solid solution formation and densification of the reacted powders were done at 1900 °C or 1950 °C utilizing two-step spark plasma sintering. Chemical compositions were measured using energy dispersive spectroscopy. Based on the transition metal distribution in the dual phase ceramic, individual mid entropy boride and carbide ceramics were produced using the same conditions. The final microstructures had submicron grains due to the pinning effect of the two phases, while grain sizes of the individual mid entropy carbides and borides were higher than the two-phase ceramics. Vickers hardness values for dual phase ceramics were higher than values calculated using a volumetric rule mixtures from individual components. Thermal and electrical properties were also higher values than calculated using volumetric rule mixtures of individual components. Thermal conductivity of the optimized dual phase ceramic produced at 1950 °C displayed an increase of ~15% compared to the constituent phases
Comparative evaluation of the CeF3 and GD-doped CeF3 nanoparticles induced cytotoxicity in HeLa cells
No full textNanomaterials based on rare-earth fluorides, such as cerium(III) fluoride (CeF₃) and gadolinium-doped (Gd-doped) fluoride nanoparticles, exhibit the ability to modulate oxidative stress, mitochondrial function, and cellular damage, thereby selectively enhancing the radiosensitivity of tumor cells. Previous studies have demonstrated that Gd-based fluoride nanomaterials could possess pronounced radiosensitizing potential accompanied by increased production of reactive oxygen species and radiation-induced apoptosis in cancer cells. In line with these findings, the aim of this study was to evaluate the cytotoxic effects of CeF₃ and CeF₃:Gd (15%) nanoparticles using the XTT viability assay on the human HeLa cell line. The nanoparticles were applied at concentrations of 0.5, 1, 2, 4, and 8 mg/mL, and cell viability assessed following 24 hours of treatment. The results show that CeF₃ induces a mild, dose-dependent reduction in viability (76–87%), indicating low cytotoxicity. In contrast, CeF₃:Gd (15%) nanoparticles exhibit a markedly stronger cytotoxic effect (56–72%), with a linear decline in viability and a substantially lower IC₅₀ value. These findings indicate that gadolinium doping significantly enhances the cytotoxic potential of CeF₃ nanoparticles toward HeLa cells, suggesting that Gd-modified fluoride nanomaterials may represent a more effective platform for the development of antitumor and radiosensitizing agents. The results provide a basis for future studies focusing on the underlying mechanisms of action and the evaluation of combined therapeutic approaches.5th International Student Conference – DISC2025, 11-12th December 2025, Novi Sad
Cavitation erosion resistance of some refractory ceramics
No full textCavitation erosion can be observed as a hazardous phenomenon that has a significant impact on the behavior and lifetime of engineering materials under operating conditions. This phenomenon is a result of fluid flow conditions and can cause the formation of pits and defects, resulting in not only reduced mechanical properties but also a potential risk of hydraulic system components failure and break. The study presents the results of cavitation erosion resistance tests of cordierite-based and alumina-based refractories (low cement high alumina castable). The samples are tested using a standardized procedure, the ultrasonic vibratory method with stationary specimens, for 150 minutes. The samples' degradation is evaluated by measuring and determining the rate of mass and volume loss, as well as the changes in the morphological parameters of defects occurring at the surface. Image analysis is used to determine pit characteristics such are number, average diameter, area, and roundness. The obtained results show that the dominant mechanism for the degradation of the cordierite samples is pit formation, as the number of pits increases for all times of exposure, while for the low cement castable degradation is in the form of grains, with low roundness
Normativni okvir bezbednosno-obaveštajnog sistema Republike Srbije i mogućnosti za njegovo unapređenje
No full textEvery state forms its national security system to protect its national interests and national values. Since these interests and values differ from state to state, national security systems also differ. The structure of a national security system is influenced not only by internal factors within the state, but also by external factors, such as regional relations and contemporary international dynamics. A National Security Strategy functions as an overarching document in this area, defining national interests and values, the system and internal relations, as well as challenges, risks, and threats to national security. Certain actors within the system, such as the police, military, and security-intelligence agencies, hold the authority to apply specific instruments, resources, and methods to protect the proclaimed values and interests. These actors must respond to all challenges, risks, and threats that may arise, which requires significant resources and methods that are not always publicly visible. This article provides an overview of the normative framework regulating the functioning of the security-intelligence system of the Republic of Serbia, the competences and powers of its security services, as well as their organization and coordination.Svaka država formira sistem nacionalne bezbednosti radi zaštite sopstvenih nacionalnih interesa i nacionalnih vrednosti. S obzirom da se nacionalni interesi i nacionalne vrednosti razlikuju od države do države, razlikovaće se i njihovi sistemi nacionalne bezbednosti. Takođe, na različito ustrojstvo sistema nacionalne bezbednosti utiču i unutrašnji faktori koji postoje u državi, ali i spoljašnji faktori, poput odnosa u regionu i aktuelnih međunarodnih odnosa. Strategija nacionalne bezbednosti je svojevrstan krovni dokument u ovoj oblasti u kome svaka država definiše svoje nacionalne vrednosti i nacionalne interese, celokupan sistem i odnose u njemu, kao i izazove, rizike i pretnje po nacionalnu bezbednost. Pojedini akteri sistema, kao što su policija, vojska i bezbednosno-obaveštajne službe, imaju ovlašćenja da primene pojedina sredstva, resurse i metode kako bi zaštitili proklamovane vrednosti i interese. Pomenuti akteri moraju da odgovore svim izazovima, rizicima i pretnjama koji se mogu pojaviti po nacionalnu bezbednost države i stoga njihova sredstva i resursi ne mogu biti mali, a metode vidljive. U radu je dat pregled normativnog okvira kojim je uređen način funkcionisanja bezbednosno-obaveštajnog sistema Republike Srbije, nadležnosti i ovlašćenja službi bezbednosti, kao i način njihove organizacije i koordinacije
Cold-sintered bioceramics for medical applications: State of the art and further perspectives
No full textCold sintering has recently emerged as a promising approach for preparing dense ceramic materials and composites at low temperatures. It relies on utilizing transient, typically externally introduced, liquid phases to accelerate material diffusion and densification under applied pressure. Cold-sintered bioceramics, especially those prepared at temperatures below 100°C, may open up numerous possibilities, not only in producing dense ceramics with refined microstructural properties and reduced time/energy costs, but also in developing multifunctional platforms containing bioactive compounds, therapeutics, growth factors, and signaling molecules for enhanced and targeted biological responses. Cold sintering in the presence of liquids inherently involves dissolution and nucleation, which become particularly intricate under applied pressures and elevated temperatures. Pseudo bio-mineralization, an auspicious approach for tailoring synthetic bone grafts toward targeted mechanics, may serve as a viable route for enhancing the densification mechanisms inherent to cold sintering. We have carefully analyzed the current state of the art in cold-sintered bioceramics and the results achieved, with a focus on the chemistry of the employed liquids and the corresponding changes upon sintering, the selection of transient phases, and mineral nucleation, while also addressing the potential for developing new biomaterials. Despite the widely accepted classical dissolution– precipitation strategy, no clear roadmap can yet be defined regarding the type and amount of liquid phase that should be applied, at least in the case of hydroxyapatite (HAp) densification–the most important representative of calcium phosphates. We strongly advocate the use of water as the transient liquid of choice in the cold sintering of HAp-based bioceramics, instead of strong acids/bases, and emphasize the importance of understanding the various processes and parameters that govern and connect solution chemistry to mineral nucleation. This understanding will enable the advancement of cold sintering protocols in a target-oriented manner, and we provide perspectives on future developments, including practical advice
Poster: Green innovations for healthier and more sustainable solutions within the VIVENDI project
No full textThree-quarters of cancer-fighting agents in medical use are derived from natural sources. However, their extraction from biomass requires significant quantities of volatile and toxic organic solvents, posing substantial risks to human health and the environment. Additionally, these bioactive compounds (BACs) often exhibit low bioavailability after administration, insolubility in water, and instability. Addressing these challenges, the Vivendi project (Green Innovation: Unlocking the Bioactive Potential of Biomass for Enhanced Pharmaceuticals and Foods through Eco-Friendly Sustainable Technologies), under the call Dijaspora2023, addresses these challenges by developing an integrated, eco-friendly extraction and formulation strategy that replaces conventional solvents with sustainable alternatives and enhances BAC stability through micellar encapsulation. A novel liquid–solid membrane extraction process, employing a membrane micromixer, has been applied for the first time to simultaneously isolate and micellize target compounds. Two model systems are investigated: (i) one-step extraction of BAC from raspberry using bio-based ionic liquids and natural deep eutectic solvents, and (ii) extraction of parthenolide from feverfew using an aqueous biphasic system formed with biocompatible Pluronic-type biopolymers and bio-based ionic liquids. To further improve stability, BACs are microencapsulated using different encapsulation techniques (spray and freeze-drying, and Lego-Inspired Microfluidic encapsulation), using different biopolymers, and thoroughly characterized with advanced analytical techniques. The knowledge generated within the VIVENDI project will enable the valorization of biomass and herbal residues, reduce industrial waste, and establish a novel, cost-effective green technology for BAC isolation and preservation, leveraging the multidisciplinary expertise of the VIVENDI consortium members.Abstract: [https://vinar.vin.bg.ac.rs/handle/123456789/15978