Vinča Institute of Nuclear Sciences
Repository of the Vinča Institute of Nuclear Sciences (VinaR)Not a member yet
15953 research outputs found
Sort by
Excitation enhanced and tuned in Cs2KGaF6: Cr3+, Mn4+ with significantly improved EQE applied for NIR pc-LEDs
No full textRecently, Cr3+-doped fluoride materials for phosphor-converted near-infrared light-emitting diodes (NIR pc-LEDs) have been extensively studied, however, their external quantum efficiency (EQE) must be improved. In addition, designing broadband NIR-emitting fluoride phosphors that are sufficiently excited by blue light to match with commercial 460 nm InGaN LED chips is still challenging. In this work, broadband NIR-emitting Cs2KGaF6:Cr3+, Mn4+ (CKGF:Cr, Mn) phosphors are synthesized through ion exchange route. Tunable excitation of CKGF:Cr NIR phosphor shifts from 430 nm to 460 nm by co-doping with Mn4+, which could serve as an additional strategy to improve the photoluminescence of Cr3+-doped broadband NIR-emitting phosphors. The NIR emission of CKGF:Cr, Mn is significantly improved, with internal quantum efficiency (IQE) and EQE of 85.9% and 29.0%, respectively. The Mn-free CKGF:Cr phosphor, in comparison, has an EQE of only 15.8% (λex λex = 467 nm) and 20.0% (λex = 433 nm). Furthermore, with excellent thermal stability, CKGF:Cr, Mn phosphor are well suitable for LED applications and the fabricated NIR pc-LED device has high photoelectric efficiency (19.4%@20 mA) and it well performs in night vision, quick inspection and strengthening for deep colors. The described ion exchange method of Cr3+-doped fluoride NIR phosphors by co-doping with Mn4+ is an attractive strategy for optimizing the luminescent properties of blue-excited NIR phosphors. © 2025 Elsevier B.V
In Vivo, In Vitro, and In Silico Assessment of Anticancer Activity of the New Pincer-Type Pt(II) Complexes
No full textTwo new complexes [Pt(L1)Cl]Cl (Pt1) and [Pt(L2)Cl]Cl (Pt2), (L1 = N2,N6-bis(5-methylthiazol-2-yl)pyridine-2,6-dicarboxamide and L2 = N2,N6-di(benzo[d]thiazol-2-yl)pyridine-2,6-dicarboxamide), were synthesized and characterized. The rate of nucleophilic substitution reactions of complexes with l-methionine (l-Met), l-cysteine (l-Cys), and guanosine-5′-monophosphate (5′-GMP) decreases in the order of biomolecules reactivity: l-Met > l-Cys >5′-GMP. The complexes exhibited moderate binding affinity for calf thymus DNA and human serum albumin. Competitive binding studies of complexes with DNA in the presence of ethidium bromide and Hoechst 33258 revealed that minor groove binding is more dominant over intercalation. Pt1 was more selective and effective in decreasing the viability of 4T1 breast cancer cells by promoting both early- and late-stage apoptosis. The in vivo findings reinforced these results, demonstrating that Pt1 significantly reduced tumor growth while exhibiting minimal systemic toxicity. Molecular docking complemented experimental data, confirming DNA and HSA binding for both complexes, while Pt1 aligned better with pro-apoptotic activity under physiological conditions
A computational framework for the design and development of ERK2 and multi-target ERK2/HDAC inhibitors
No full textThe Ras-Raf-MEK-ERK/MAPK signaling pathway regulates important cellular processes such as proliferation, differentiation, apoptosis, development and stress responses. This signaling pathway is overexpressed in various types of cancer, with ERK2 (Extracellular signal - Regulated Kinase 2) serving as the final effector component. Current inhibitors of this pathway, including ERK2 inhibitors, face challenges such as safety concerns, limited efficacy and resistance, highlighting the need for new therapeutic candidates. In this study, ML-QSAR (Machine Learning - Quantitative Structure-Activity Relationships) and 3D-QSAR (Three-Dimensional Quantitative Structure-Activity Relationships) models and molecular docking of the investigated compounds were used to identify key structural features related to ERK2 inhibitory activity. This computational framework formed the basis for a fragment-based drug design that enabled the development and evaluation of new ERK2 inhibitors from two distinct structural classes, pyrimidine-2-pyridone and pyrazolyl-pyrrole derivatives. Molecular dynamics simulations were performed for the best designed ERK2 inhibitor. The developed computational framework was successfully used for the design and evaluation of multi-target ERK2/HDAC inhibitors as a basis for future cancer therapies. © 2025 Elsevier Lt
Eu2+/Eu3+ doped Al2O3 coatings formed on tungsten by plasma electrolytic oxidation: photoluminescent properties and application in luminescence thermometry
No full textPlasma electrolytic oxidation (PEO) was employed to synthesize Eu2+/Eu3+ doped Al2O3 coatings on tungsten substrates using an alkaline phosphate electrolyte containing Eu2O3 particles at ambient conditions, eliminating the need for high-temperature or reducing atmospheres. The structural, morphological, and photoluminescence (PL) properties of the coatings were investigated. X-ray diffraction (XRD) confirmed the formation of alpha Al2O3 as the dominant phase. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis demonstrated uniform coatings with increasing europium content at higher Eu2O3 concentrations. The PL spectra exhibited characteristic emissions from both Eu2+ (broadband 4f65d1 → 4f7) and Eu3+ (sharp 5D0 → 7FJ) transitions, confirming the coexistence of both valence states. Eu3+ excitation spectra feature a charge transfer band and 4f-4f transitions. There is a negligible energy transfer between Eu2+ and Eu3+ ions. The local coordination of Eu3+ and Eu2+ ions in Al2O3 coatings is analyzed using the PL spectra, showing that both ions are in low-symmetry sites. The luminescence intensity ratio (LIR) of Eu2+/Eu3+ emissions was utilized for optical thermometry from 300 K to 650 K, showing a quasi-Boltzmann temperature dependence. The temperature-dependent PL studies revealed high absolute sensitivity (0.0008 K−1 @ 575 K), demonstrating the potential of Eu2+/Eu3+ doped Al2O3 coatings for contactless luminescence thermometry applications. © 2025 Elsevier B.V
Comparative analysis of antibacterial and antibiofilm potential of chemically- and green laser-produced gold and silver nanoparticles against dental pathogens
No full textObjectives: This study compared antibacterial and antibiofilm effectiveness of chemically (chem_) and pulsed laser ablation-synthesized (laser_) gold (Au) and silver (Ag) nanoparticles (NPs), namely chem_AuNPs, chem_AgNPs, laser_AuNPs, and laser_AgNPs, against four Streptococcus species (S. mutans, S. mitis, S. sanguinis, and S. gordonii), essential for cariogenic biofilm development. Design: Nanoparticles were characterized for size and stability using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Their antibacterial and antibiofilm activities were tested in microdilution and crystal violet assays, respectively. Ex vivo evaluation of the nanoparticles antibiofilm activity was performed against a four-species biofilm on enamel discs by quantifying CFU. Scanning electron microscopy was used to visualize the reduction in biofilm mass on enamel discs treated with laser_Au and Ag nanoparticles. Results: TEM showed nanoparticle sizes ranging 5.89–18.49 nm. DLS revealed the stability of NPs colloid solutions, with ζ-potential approximately 30 mV over 21 days. All NPs exhibited strong antibacterial activity, with MIC values of 56.9–120.6 μg mL-1 for chem_AuNPs and 1.9–30.8 μg mL-1 for all the rest. The evaluation of NPs potential in biofilm prevention showed the following trend in activity: laser_AuNPs>laser_AgNPs>chem_AuNPs>chem_AgNPs. AuNPs, regardless of synthesis method, were as effective as the positive control (chlorhexidine-mouthwash) against the multispecies biofilm settled on enamel discs, while AgNPs were nearly twice as efficient. Conclusions: AuNPs and AgNPs could be alternatives for managing cariogenic bacteria both planktonic and within biofilms. Laser_AgNPs, being more efficient than commercial mouthwash, seem to be the most valuable candidate
Numerical analysis of tensile behaviour of Ti-13Nb-13Zr alloy after anodic oxidation
No full textThe surface of coarse-grained Ti-13Nb-13Zr (CG TNZ) alloy was modified using the anodic oxidation. In order to obtained
nanostructured oxide layer, as electrolyte in surface modification process 1M H3PO4 + NaF was used, while anodizing time was
90 minutes. The modified surface morphology was analyzed using the field emission scanning electron microscopy (FE-SEM)).
It was realized that anodic oxidation led to the creation of the oxide layer consisted of nanotubes. Tensile characteristics of the
CG TNZ alloy, before and after anodic oxidation, were determined by tensile testing. Tensile testing was performed using Micro
Tensile Specimens (MTS) with a rectangular cross-section. The anodic oxidation led to a decrease of tensile characteristics of the
CG TNZ alloy. In order to better understand tensile behaviour of the CG TNZ alloy after anodic oxidation, numerical analysis
was done. The 3D numerical model of MTS, which simulated the tensile test, was made in Abaqus software package. Numerical
results were obtained using the complete Gurson model (CGM), which is micromechanical model used for the ductile fracture of
metallic materials. The parameter that quantifies the damage in the material, that is, the volume fraction of voids or porosity, is
varied. So the value of the damage parameter, the initial void volume fraction, f0, was 0.01 and 0.005. In addition to the
elongation of the MTS, the reduction of the cross-sectional thickness at the neck of MTS was also considered. Results showed
that CGM for the initial value of the damage parameter 0.005 predicts the failure of the MTS at the corresponding value of
thickness reduction
Chitosan–Hydrazone-Modified Calcium Phosphate Scaffolds: Fabrication, Characterization, and Drug Delivery Potential
No full textBackground/Objectives: Recent advancements in biomaterials aimed at closely mimicking natural biological tissues hold great promise for hard tissue regeneration and controlled drug release due to their superior physical, chemical, and biological properties. This study aimed to develop multi-ion doped calcium hydroxyapatite (HAp) scaffolds with chitosan-based coatings for localized drug delivery, incorporating a novel hydrazone compound with potential anticancer activity. Methods: HAp powders doped with magnesium (Mg2+), strontium (Sr2+), and varying fluoride (F−) contents (0–2 mol.%) were synthesized via a hydrothermal method. Scaffolds were fabricated using the sponge replica technique and subsequently coated with chitosan or a chitosan–hydrazone blend. Dopant incorporation was confirmed by electron dispersive X-ray spectroscopy (EDS). Phase composition and morphology were analyzed via X-ray diffraction (XRD) and scanning electron microscopy (SEM). Mechanical properties, bioactivity, cytotoxicity, and hydrazone release profiles were systematically evaluated. Results: EDS confirmed successful incorporation of Mg2+ and Sr2+ in all powders, while F− was detected only in powders with 1 and 2 mol.% fluoride. XRD and SEM revealed the phase composition and scaffold microstructure. Chitosan coatings significantly improved scaffold compressive strength and reduced degradation rate, indicating enhanced stability in biological environments. The coated scaffolds supported MRC-5 fibroblast viability. The hydrazone compound exhibited dose-dependent antitumor cytotoxicity comparable to cisplatin and showed sustained release from scaffolds for up to 15 days. Conclusions: The combination of multi-ion doped HAp scaffolds and chitosan–hydrazone coatings provides a promising platform for bone tissue engineering and localized cancer therapy, demonstrating both mechanical stability and controlled, sustained drug release
Effect of Fe2O3 on Compressive Strength and Microstructure of Porous Acicular Mullite
No full textPorous acicular mullite was fabricated at 1300 °C starting from Al2O3 and mixture of SiO2 and MoO3 obtained by previous oxidation of waste MoSi2. It was found that the presence of MoO3 favors formation of acicular (prism-like) mullite grains with sharp edges. The effect of addition of Fe2O3 (4–12 wt.%) on phase composition, compressive strength, thermal conductivity and microstructure was studied. The addition of Fe2O3 improved the compressive strength from approximately 25 MPa in pure mullite to about 76 MPa in samples containing 12 wt.% Fe2O3, while the open porosity decreased from 55.4% to 51.8%. The presence of Fe2O3 caused a decrease in mullite formation temperature owing to the formation of liquid phase and accelerated diffusion. The solubility of iron oxide in mullite lattice was between 8 and 12 wt.% Fe2O3. The incorporated iron ions also promoted the rounding of sharp edges in prismatic mullite grains, leading to a reduced specific surface area of 0.55 m2/g in the sample with 12 wt.% Fe2O3. The thermal conductivity of mullite increased with addition of 12 wt.% Fe2O3 reaching value of 1.17 W/m·K
Phases of Integrated Risk Management in CBRN Risk Mitigation and Recovery
No full textThis paper examines integrated risk management approaches for CBRN (Chemical, Biological, Radiological, and Nuclear) threats, focusing on preparedness, mitigation, response, and recovery phases. It explores the challenges posed by these threats, which can have significant and widespread impacts, and emphasizes the importance of effective planning, training, and cooperation among relevant stakeholders. The role of a modern approach to disaster risk reduction and community resilience in strengthening CBRN management is also discussed. The findings are based on a review of existing literature and provide insights into current practices and effective approaches for reducing these risks.12th International Conference IcETRAN 2025 Čačak, June 9-12, 2025
Hydrothermal treatment of GO-based nanocomposites for energy storage: New insights into the components’ interaction
No full textIn this study, graphene oxide (GO)-based nanocomposites with 12-tungstophosphoric acid (WPA) and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), 15 wt.% each, were hydrothermally treated (HTT) at 180 °C for 8 hours to investigate their electrochemical charge storage capabilities. Structural and compositional changes were evaluated via FTIR, XPS, TPD, and LDI-MS, while morphological characteristics were analyzed using SEM and TEM. FTIR confirmed the presence of primary oxygen-containing groups in GO and successful incorporation of modifiers, while the XPS data indicated HTT-induced reduction of these groups, particularly epoxides. TPD revealed an increased desorption of surface functionalities after HTT, especially above 500 °C. SEM showed the evolution of the layered GO morphology into a hierarchically porous matrix, while TEM confirmed nanoscale integration of PTCDA and deposition of WPA nanostructures across the GO surface. Notably, LDI-MS provided complementary insight into the molecular-level interactions. The spectrum of HTT-treated GO/PTCDA displayed distinct Cn and Cn(CH)m cluster distributions compared to untreated GO, with a reduced intensity of OH- ions post-treatment, confirming the reduction of GO surface. Fragment ions characteristic of PTCDA, absent in the spectrum of pure PTCDA, were observed only after HTT. For GO/WPA/PTCDA, LDI-MS revealed fragment ions from both PTCDA and WPA, including characteristic polyoxometalate species at m/z 232–928 and a [W₁₂O₄₁]²⁻ peak at m/z 2862. After 8 hours of HTT, the nanocomposites formed a hierarchical structure resulting in enhanced capacitive behavior. Cyclic voltammetry showed a specific capacitance of ~300 F/g for GO/PTCDA, which is attributed to improved interfacial properties, high electron affinity of PTCDA and suitable morphology. These findings reveal important changes of structure and surface chemistry at the molecular level of GO-based nanocomposite which is of importance for the rational design of GO-based electrodes for high-performance supercapacitors.5th International Meeting on Materials Science for Energy Related Applications, September 25-26, 2025, Belgrade