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High-Temperature Negative-Thermal-Quenching in Broadband NIR Light-Emitting ScF3:Cr3+ Phosphors
No full textBroadband near-infrared (NIR) phosphors with superior thermal stability are critical enablers of high-power NIR pc-LEDs, emerging as essential light sources for NIR spectroscopy applications. In this work, an unprecedented high-temperature negative thermal quenching (NTQ) phenomenon persisting up to 500 K is reported in Cr3+-activated ScF3 phosphors, which emit broadband NIR emission in the 700–1200 nm (λem = 850 nm, FWHM = 132 nm). The theoretical calculations employing the Exchange-Charge Model (EMC) for crystal field parameters of Cr3+ ions in [ScF6] octahedral sites remain in perfect agreement with the experimental results. Critically, Yb3+-codoping enables efficient Cr3+ → Yb3+ energy transfer, achieving substantial spectral broadening (FWHM = 254 nm) and significantly enhanced thermal stability. The temperature-dependent X-ray diffraction (XRD) and theoretical calculations reveal that anisotropic F-atom vibrations drive negative thermal expansion (NTE) in cubic ScF3, distorting [ScF6] octahedra. It is demonstrated that synergistic electron-phonon coupling and NTE-driven structural dynamics underpin the superior thermal stability of NIR emission. These findings establish a design paradigm for new broadband NIR phosphors with outstanding thermal stability for next-generation high-power NIR pc-LED applications
Essential oil of Satureja montana as a multifunctional agent: Insights into antioxidant activity, antibacterial properties, cancer cell cytotoxicity, and cell cycle effects
No full textIn this study, the antibacterial, antioxidant, and anticancer effects of essential oil extracted from the aromatic plant species Satureja montana from Montenegro were examined. Chemical characterization of S. montana essential oil (SMEO) was performed using GC-MS. The antibacterial activity was assessed using the microdilution method and antioxidant activity was measured using DPPH and FRAP assays. Cytotoxicity was examined in cancer cell lines and normal fibroblasts using the MTT assay. Flow cytometry was used to examine cell cycle, cell death, and cytoprotective effects. The effects on gene and miRNA expression were investigated using RT-qPCR. Oxygenated monoterpenes and monoterpane hydrocarbons were the most abundant in SMEO, with p-cymene (28.65%), thymol (22.1%), linalool (4.86%), trans-caryophyllene (4.52%), and carvacrol (3.28%) as the major compounds. SMEO had inhibitory effect on growth of 6 bacterial strains, with MIC values ranging from 0.78 μL/mL to 12.5 μL/mL. SMEO showed antioxidative activity with an EC50 value of 3.44 μL/mL. Strong cytotoxic activity of SMEO was observed against cervical adenocarcinoma HeLa, malignant melanoma A375, colorectal adenocarcinoma LS 174T, and lung carcinoma A549 cells (IC50 from 0.12 to 0.18 μL/mL). Treatment with SMEO triggered apoptosis in HeLa cells, decreased MMP2 gene expression levels, and increased the expression of tumor-suppressive miR-16 and miR-34a. SMEO decreased the levels of reactive oxygen species in normal fibroblasts MRC-5. Numerous beneficial biological properties, including antibacterial, antioxidant, and cytoprotective effects, in addition to the strong cytotoxicity, proapoptotic, and anti-invasive effects of SMEO, suggest its prospective role in the treatment of different human diseases, including cancer
Tailoring red and deep-red light: Bi3+ doped Sr2Gd0.2Eu0.8F7 phosphors for next-generation horticultural LEDs
No full textEu3+-activated inorganic phosphors are widely used in general lighting and display technologies due to their
strong orange/red (
5
D0 → 7
F1,2) emissions with wavelengths shorter than 630 nm. However, phosphors activated
by Eu3+ that strongly emit in the deep-red region, driven by the 5
D0 → 7
F4 transition (>700 nm), are relatively
uncommon. This limitation hinders their applicability in horticultural light emitting diodes, where light in the
photosynthetically active radiation range, particularly deep-red photons, is crucial for regulating plant growth.
Hereby, we prepared Bi3+-doped Sr2Gd0.2Eu0.8F7 nanoparticles using the hydrothermal synthesis method, to
address this challenge. Introducing Bi3+ significantly enhanced Eu3+ emission under near-UV excitation, with an
optimal 1 mol% Bi3+ concentration yielding a 250 % increase in integrated emission intensity and a long
emission lifetime of 9.3 ms compared to the Bi3+-free sample. The optimized phosphor also demonstrated
exceptional thermal stability, retaining 93 % of its room-temperature emission at 200 ◦C. These results highlight
that Bi3+-doping of Sr2Gd0.2Eu0.8F7 host is a promising strategy for designing thermally robust, deep-red-emitting
nanophosphors. Such properties underline their potential for next-generation horticultural LED applications
aimed at improving plant growth efficiency
The influence of sodium chloride aqueous solution on austenite steel corrosion
No full textCorrosion is an undesirable damage to a material caused by the physicochemical influence of the external environment. Generally, austenitic steels have exceptional physicochemical properties and the highest corrosion resistance. However, their tendency to form corrosion products can reduce their functionality and be a significant problem in various industries (e.g., electronics or medicine). The objective of this study was to examine the behaviour of austenitic steel SS316 after standing in an aqueous solution of sodium chloride for a defined period. Optical microscopy was used to inspect the changes in the austenitic steel's surfaces. Scanning electron microscopy (SEM) showed a more precise surface topology of steel samples before and after induced corrosion. The microsurface before the experiments was pure without corrosion, due to the formation of a thin passive film on the surface. After exposure to the sodium chloride solution, it was observed that a precipitate had formed on the surface after adsorption of sodium and chloride ions. A semiquantitative method of Energy-dispersive X-ray spectroscopy (EDS) coupled with SEM was used to discover modifications in the ingredients distribution of austenitic steels exposed to the action of sodium chloride aqueous solution. The corrosion changes in the austenitic stainless steel samples were assessed as pitting. EDS spectra showed different elemental contents between the clean surface positions, near the corrosion deposits, in the deep corrosion pit, and the wide pit zone. These findings are important for the safe usage of steel, especially in medicine, to reduce the infection risk from rust and other imperfections triggered by oxidation.16th International Symposium „Novel Technologies and Sustainable Development“ Leskovac, October, 17-18, 2025. [https://doi.org/10.46793/89429-60.boa
Comparative evaluation of the empirical (Rusle) model and the nuclear (137Cs) method in the assessment of water erosion in complex catchments
No full textPouzdano određivanje stope erozije zemljišta i njenih prostornih varijacija u slivovima
kompleksnih fiziografskih karakteristika predstavlja veliki izazov kako za globalnu naučnu
zajednicu, tako i za donosioce odluka. U ovom radu su predstavljena dva različita pristupa
određivanju stopa erozije: modelovanje potencijalnih stopa erozije revidiranom univerzalnom
jednačinom gubitka zemljišta (RUSLE) i kvantifikovanjem stopa redistribucije zemljišta
primenom nuklearne (137Cs) tehnike. Pored uporednog pregleda osnova, mogućnosti i
ograničenja ovih metoda, diskutovane su prednosti njihove kombinovane primene na
dostupnim primerima iz literature, uključujući i sliv na teritoriji Republike Srbije. Poređenje
stopa erozije procenjenih na osnovu dve metode u svetlu različitih procesa koje opisuju,
različitih vremenskih i prostornih okvira, kao i njihovih ograničenja, pruža pouzdanije procene
gubitka zemljišta i doprinosi boljem razumevanju dinamike erozionih procesa u kompleksnim
slivovima.Reliable determination of soil erosion rates and their spatial variations in catchments with
complex physiographic characteristics represent a significant challenge for both the global
scientific community and decision-makers. This paper presents two approaches for assessing
erosion rates: modeling potential erosion rates using the Revised Universal Soil Loss Equation
(RUSLE) and quantifying soil redistribution rates using the nuclear (137Cs) technique. In
addition to providing a comparative overview of these methods' foundations, possibilities, and
limitations, the paper discusses the advantages of their combined application, supported by
examples from the literature, including a case study in the Republic of Serbia. A comparison of
erosion rates estimated by the two methods in light of the different processes they describe,
different temporal and spatial frameworks, and their limitations yields more reliable estimates
of soil loss and enhances our understanding of erosion dynamics in complex catchments.XXXIII симпозијум ДЗЗСЦГ [Друштва за заштиту од зрачења Србије и Црне Горе] : 1-3. октобар 2025. године
Proteomic Signatures of Hippocampal Nonsynaptic and Synaptosome-Enriched Mitochondria in Rats Resilient to Chronic Social Isolation
No full textChronic social isolation (CSIS), a known risk factor for the development of major depressive disorders, is associated with hippocampal dysfunction. In rodent models, CSIS produces two phenotypes: CSIS-susceptible, which develop depressive- and anxiety-like behaviors, and CSIS-resilient, which maintain normal behavior despite stress. However, the biological mechanisms underlying resilience to stress remain elusive. Mitochondria, as central regulators of neuronal energy metabolism and redox balance, are potential mediators of stress susceptibility and resilience. This review summarizes comparative proteomic analyses of hippocampal nonsynaptic mitochondria (NSM) and synaptosome-enriched mitochondria from CSIS-susceptible and CSIS-resilient rats along with controls. In NSM of resilient rats relative to susceptible rats, remodeling enhanced energy production, limited reactive oxygen species, stabilized phosphate transport, and promoted removal of damaged components. Compared with controls, these changes optimized energy production, and selectively downregulated oxidative stress-promoting proteins. Conversely, synaptosome-enriched mitochondria from resilient rats showed downregulation of proteins related to synaptic energy metabolism and redox balance relative to CSIS-susceptible rats, but demonstrated upregulation of bioenergetic and antioxidant enzymes, molecular chaperones, and neuroprotective factors compared with controls. These proteomic signatures both highlight mitochondrial adaptability in promoting stress resilience and identify mitochondria as promising targets for the development of novel antidepressant therapies
Structure–Property Relationship in Isotactic Polypropylene Under Contrasting Processing Conditions
No full textPolypropylene (PP), with its good physical, thermal, and mechanical properties and excellent processing capabilities, has become one of the most used synthetic polymers. It is known that the overall properties of semicrystalline polymers, including PP, are governed by morphology, which is influenced by the crystallization behavior of the polymer under specific conditions. The most important industrial PP remains the isotactic one, and it has been studied extensively for its polymorphic characteristics and crystallization behavior for over half a century. Due to its regular chain structure, isotactic polypropylene (iPP) belongs to the group of polymers with a high tendency for crystallization. The rapid quenching of molten iPP fails to produce a completely amorphous polymer but leads to an intermediate crystalline order. On the other hand, slow cooling yields a material with high crystalline content. The processing conditions that occur in practice and industry are between these two extremes and, in some cases, are even very close. Therefore, the study of limits in processability and the impact of extreme preparation conditions on morphology, structure, thermal, and mechanical properties fills a gap in the current understanding of how the processing conditions of iPP can be used to design the desired properties for specific applications and is in the focus of this research. The first set of samples (Q samples) was obtained by rapid quenching, while the second was prepared by very slow cooling from the melt to room temperature (SC samples). Testing of samples was performed by optical microscopy (OM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), dynamic dielectric spectroscopy (DDS), and mechanical measurements. Characterization revealed that slowly cooled samples exhibited a significantly higher degree of crystallinity and larger crystallites (χ ≥ 55% and L(110) ≈ 20 nm), compared to quenched samples (χ 500%, while slowly cooled samples broke below 15%, reflecting their brittle behavior. For the first time, DDS is applied to investigate molecular mobility differences between processing-dependent structural forms, specifically the mesomorphic (smectic) and α-monoclinic forms. In slowly cooled samples, α relaxation exhibited both enhanced intensity and an upward temperature shift, indicating stronger structural constraints due to a much higher crystalline phase content and significantly larger crystallite size, respectively. These findings provide novel insights into the structure–property–processing relationship, which is crucial for industrial applications
Asymmetric T-segment binding and gate dynamics govern the final stages of the type IIA topoisomerase catalytic cycle
No full textType IIA DNA topoisomerases are molecular nanomachines that alter DNA topology during essential cellular processes. The final steps of their catalytic cycle, after translocation of the transported (T-) segment into the C-gate, are still not fully understood. Here, we performed all-atom molecular dynamics simulations of several conformational states of Saccharomyces cerevisiae topoisomerase IIA, each with a T-segment inserted into the C-gate. Bound ATP and ADP nucleotides allosterically modulated the N-gate dynamics, likely stabilizing the dimer and preventing premature dissociation. The T-segment was asymmetrically bound and stabilized within the C-gate by positively charged residues, and this gate remained structurally rigid, highlighting its role as a retention site. The positioning of the T-segment in the C-gate allosterically influenced the G-segment to a straighter geometry that favors religation and release. Our simulations support coordinated release of DNA segments and point to a potentially important role for dynamic communication between the gates in the mechanism. These results provide new insights into the late stages of the catalytic cycle and highlight the intertwined roles of nucleotide binding, DNA topology and coupled protein domain dynamics in regulating this important enzyme
Progress in diabetes diagnostics and treatment monitoring: breakthroughs in molecular and clinical testing
No full textPerformance Evaluation of a Four-Matrix-Based Method for Synthesizing a 12-Lead Electrocardiogram from 3-Quasi-Orthogonal Leads
No full textMobile ECG devices effectively detect arrhythmias but often miss acute conditions like heart attacks due to the limited data from just 1-2 leads. We have recently proposed a novel method of ECG synthesis for synthesize 12-lead ECG from 3 quasiorthogonal ECG leads using a 4-matrix (4M) transformation. The approach employs four personalized matrices to reconstruct the P wave, QRS complex, ST segment, and T wave, calibrated from non-simultaneous 3-lead and 12-lead ECG measurements. Here we provide a detailed account on the method testing on the recordings obtained from 64 healthy volunteers. The method outperforms the EASI-based synthesis, achieving a mean cross-correlation (CC) of 0.96 versus 0.89 for EASI. Morphology and cardiac angle agreement, assessed via Pearson R-correlation, is also superior. The 4 M method enables reliable diagnostic interpretation, making it suitable for converting mobile 3-lead ECG device data into accurate synthesized 12-lead recordings