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Synthesis, spectroscopic and computational examination of an optically active E-N'-2,3-dimethoxybenzylidene-4-nitrobenzohydrazide crystal
No full textA new hydrazide derivative, (E)-N′-(2,3-dimethoxybenzylidene)-4-nitrobenzohydrazide (DB4N), was synthesized by condensation of 2,3-dimethoxybenzaldehyde with 4-nitrobenzohydrazide, and its molecular structure was confirmed by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, and C − N and N − N bond lengths prove the existence of extended π-electron delocalization. The crystallographic structure is stabilized by intra- and intermolecular hydrogen-bonding interactions, as revealed by Hirshfeld surface and interaction energy analyses of DB4N dimers. Experimental FTIR, FT-Raman, and UV–VIS spectra were recorded and assigned with the aid of density functional theory (DFT) calculations performed using several functionals with the 6–311++G(d,p) basis set. The optimized geometry obtained at the CAM-B3LYP level showed the best agreement with crystallographic bond lengths and angles. Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analyses provided detailed insight into intramolecular charge transfer, stabilization interactions, and the role of substituents in electron delocalization. The theoretically predicted vibrational wavenumbers exhibited excellent correlation with experimental values, as supported by potential energy distribution (PED) analysis. Time-dependent DFT (TD-DFT) calculations reproduced the observed absorption maxima and clarified the electronic transitions. The difference of 6 nm between the most intense experimental and theoretical bands was explained by the explicit interactions between DB4N and DMSO solvent molecules. Third-order nonlinear optical (NLO) properties were investigated using the Z-scan technique, yielding a susceptibility of χ3 = 6.554 × 10–4 esu, indicating significant potential for DB4N in photonic and optoelectronic applications. The combined crystallographic, spectroscopic, and computational findings highlight the title molecule's stability, electronic delocalization, and promising NLO activity
High-voltage surge impact on thick-film sensors for structural health monitoring: Resistance and noise spectroscopy analysis
No full textThis study explores the effects of high-voltage electrical surges on the performance and structural integrity of thick-film strain sensors developed for structural health monitoring in steel infrastructure. The sensors were fabricated using screen-printing techniques with a bismuth lead ruthenate-based resistive composition deposited on alumina ceramic substrates. To simulate realistic operational conditions, the sensors were mounted on steel beams and subjected to four-point bending to induce mechanical strain. Following mechanical loading, controlled high-voltage surge pulses were applied to emulate extreme electrical events. Sensor response was characterized before and after surge exposure using both static resistance measurements and current noise spectral analysis. While resistance measurements showed limited change, noise spectroscopy revealed microstructural damage undetectable by conventional means. The findings highlight the degradation mechanisms arising from electromechanical stress and demonstrate the effectiveness of noise spectroscopy as a non-destructive diagnostic tool. These results support the use of thick-film sensors in electrically demanding environments
Structural and optical modifications of TiN thin films through ion irradiation: A comparative study
No full textThis study investigates the structural and optical modifications of titanium nitride (TiN) thin films following implantation with gold (Au), silver (Ag), and copper (Cu) ions, providing new insights into the effects of different metal ions and implantation energies on TiN's dielectric properties. The films were analyzed using a combination of transmission electron microscopy (TEM), X-ray diffraction (XRD), and spectroscopic ellipsometry, offering a comprehensive view of the changes in their structure and optical response. Ion implantation induced significant morphological changes, including the formation of smaller crystallites, defects, and modifications to grain boundaries. Optical characterization revealed that the dielectric function, particularly in the near-IR region, was strongly influenced by both the type of metal ion and implantation energy, with notable variations in the unscreened plasma frequency and Drude broadening. Au implantation exhibited the greatest changes, which were attributed to defects and grain boundary formation. The results suggest that higher implantation energies not only induce more damage but also enhance optical performance by reducing the metallic character of the TiN films. This work provides new understanding of how ion implantation with different metal ions affects the dielectric properties of TiN films, contributing to improved optical properties and reduced losses compared to conventionally deposited TiN films
Vanadium-Modified TiO2 Nanotubes Synthesized Via Electrochemical Anodization and Nanosecond Pulsed Laser Deposition for Improved Photocatalytic Degradation of p-nitrophenol
No full textVanadium-modified TiO2 nanotubes were successfully prepared via a two-step method combining electrochemical anodization on Ti mesh and nanosecond pulsed laser deposition (PLD). The morphology of samples was discussed using FESEM and TEM techniques. The amount of deposited vanadium is measured using energy dispersive X-ray spectroscopy (EDS) and X-ray fluorescence (XRF). X-ray photoelectron spectroscopy (XPS) analysis showed that deposited V is mainly in the oxidation state of V4+ and V5+. Optical properties were analysed using UV-Vis DRS and photoluminescence spectroscopy (PL). With lower vanadium content (V 2 photocatalysts exhibit better photocatalytic activity, while higher vanadium content levels result in reduced activity. This indicates that the 200 V-TiO2 (V ~ 2.5 wt%) sample degraded p-nitrophenol with an efficiency of 87.6% as opposed to 69.1% for TiO2, after 300 min under simulated sunlight irradiation. Recycling photocatalytic experiment was performed to assess the durability of the photoactivities of the best V-TiO2 sample. Photoelectrochemical analyses confirmed that moderate vanadium loading significantly lowers interfacial charge-transfer resistance and optimizes band bending, consistent with enhanced photocurrent density and photocatalytic performance. This study demonstrates that nanosecond PLD enables precise control of surface vanadium content, providing an effective strategy for the design of TiO2-based photocatalysts for environmental remediation
Nonlinear kinetics and isotherm study of acid red 183 removal using chitosan and chitosan-enhanced urea–formaldehyde resin
No full textIn this study, we synthesized a new biocomposite, chitosan-modified urea–formaldehyde resin (UF/Chi), as a potential adsorbent for removing the dye Acid Red 183 (AR183) from aqueous solutions. Characterization of chitosan and the UF/Chi composite was performed using scanning electron microscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, non-isothermal thermogravimetric analysis, differential thermal gravimetry and the Brunauer–Emmett–Teller (BET) method. The results showed that the UF/Chi composite has a rough surface and macropores, resulting in a slightly higher specific surface area (SBET) of 6 m2 g−1 compared to chitosan, which has SBET of less than 5 m2 g−1. FTIR spectroscopy validated the interaction between chitosan and UF during in situ synthesis. The UF/Chi composite showed greater thermal stability, with a degradation onset (T5% = 92.1 °C) occurring later than for chitosan (T5% = 61.1 °C). Thermodynamic studies revealed that the adsorption of AR183 on both chitosan and the UF/Chi composite is spontaneous. Adsorption kinetics indicated that the double exponential model best fitted the UF/Chi composite and chitosan, followed by the Elovich model. The Sips isotherm model was optimal for adsorption on both sorbents. The processes are both physical and chemical. Maximum adsorption capacities were 24.2571 mg g−1 for the UF/Chi composite (c = 50 mg dm−3, pH = 6.27, adsorbent dosage 100 mg, T = 25 °C) and 196.5018 mg g−1 for chitosan (c = 300 mg dm−3, pH = 6.27, adsorbent dosage 75 mg, T = 25 °C). These results suggest that both materials effectively remove AR183 dye from aqueous media
From Saline Habitats to Sustainable Bioactive Polymers: Physicochemical and Biological Insights into Water Extracts from Salicornia Neei Lag
No full textThis study examines the extreme halophytic plant Salicornia neei Lag., found on the Chilean Pacific coastline, as a novel and sustainable source of highly functional polysaccharides. Polysaccharide extraction was performed using a green approach in water under mild conditions, thereby significantly minimizing energy consumption. Comprehensive characterization revealed an arabinose pectic polysaccharide (36 kDa, 34% methylation). Notably, acetylated units, constituting 25% of the polysaccharide structure, were detected in any Salicornia plant extract for the very first time. The extract demonstrated outstanding emulsification activity, achieving an impressive emulsion index of above 70% with a concentration of just 1% across five diverse edible oils (corn, canola, avocado, sunflower, and sesame). This superior performance, likely attributed to the detected acetyl groups, positions it as a potent, natural, and clean-label alternative to conventional, often synthetic, emulsifiers. Furthermore, the extract exhibited remarkable antioxidant capacities (89.47% DPPH, 71.64% ABTS, 45.40% hydroxyl radical scavenging, and 98.56% ferrous ion chelation), as well as significant antimicrobial activity against B. cereus and R. eutropha. Notably, the extract showed no cytotoxicity against healthy human fibroblast cells, confirming its safety, while displaying promising selective antitumoral activity (IC50 = 910 µg/mL; SI = 3.89) against colon cancer cells (HCT-116). Overall, these findings strongly suggest that the Salicornia neei from the Pacific Ocean represents a unique source of water-extractable polysaccharides, whose demonstrated superior biological activities—including groundbreaking emulsification, robust antioxidant and antimicrobial effects, and selective anticancer properties—collectively underscore its multifunctional potential as an innovative ingredient for diverse food, nutraceutical, and pharmaceutical applications
Concentrations and Estimation of Sources of Ultrafine Particles in the City of Belgrade at Ada Marina Urban Background Site
No full textParticulate matter is widely known as a significant air pollutant due to its proven detrimental impact on human health. Furthermore, ultrafine particles (UFPs) are those with diameters smaller than 100 nm, which can cause numerous serious health effects. Thus, identifying the sources of UFPs is essential for formulating effective mitigation strategies. Quantifying the contributions of particle sources can be performed by measuring particle number size distributions (PNSDs) for specific size ranges. This study was conducted in the city of Belgrade, the capital of Serbia, and one of the largest cities in the Balkans peninsula, which, within the European framework, belongs to a region and urban area characterized by high levels of atmospheric particulate matter pollution. In addition, there is a lack of studies addressing UFP levels and their sources in Serbia, including Belgrade. Several criteria pollutants were measured, together with the UFPs and equivalent black carbon (BC) at the urban background site in the city of Belgrade, Serbia, for the period from February to August 2024. The particle sources were analyzed using Positive Matrix Factorization (PMF) of PNSDs along with equivalent BC, PM10, PM2.5, O3, SO2, NO, NO2 and NOx. Seven source types were identified, characterized, and quantified, including two traffic sources (separated into traffic 1 and traffic 2), mixed traffic, an urban diffuse source, nucleation and nucleation growth sources, and a biomass burning source. Traffic-related sources were found to have the most significant contribution at around 40% of total particles emitted, followed by nucleation-related sources (24%) and biomass burning (20%). This is the first study performed in Serbia and Belgrade that addresses source apportionment of PNSD, for particles in the range 10–400 nm
The effects of bentonite characteristics and buffer solution composition on the adsorption of aflatoxin B1
No full textAflatoxins (AFs) are contaminants of several agricultural crops, and aflatoxin B1 (AFB1) is the most toxic AF and a known carcinogen to humans and animals. A practical solution for decontamination of animal feed contaminated with AFB1 is to use bentonite, a natural raw material consisting primarily of the mineral montmorillonite (dioctahedral 2:1 layer aluminosilicate of the smectite group). The aims of this research were to compare mineralogical, structural, chemical, and physico-chemical characteristics of three bentonites from the Balkan region (Beretnica clay from Serbia (B-Clay), Yellow clay (Y-Clay) and Gray clay (G-Clay) from Bosnia) with the characteristics of a commercial pharmaceutical-grade bentonite (P-Clay), and to study the behavior of the bentonites in phosphate buffer at pH 3 and 7 with and without AFB1. AFB1 adsorption by bentonites followed non-linear isotherms with maximum amounts adsorbed from 75.43 mg g–1 at pH 3 and 62.91 mg g–1 at pH 7 for the P-Clay to 100.25 mg g–1 at pH 3 and 78.58 mg g–1 at pH 7 for the B-Clay. The Ca-bentonites (B-Clay-cis-vacant, 83% montmorillonite; Y-Clay-cis/trans-vacant, 98% montmorillonite; and G-Clay-trans-vacant, 88% montmorillonite) were efficient adsorbents of AFB1, with the greater adsorption observed at pH 3. The P-Clay (Na/Ca bentonite, cis-vacant, 63% montmorillonite), exhibited the lowest AFB1 adsorption at both pH values. The behavior of bentonites in buffers, in the presence of AFB1, indicated that ion exchange and AFB1 adsorption by montmorillonite occurred simultaneously. Cations with larger hydrated radii (Mg2+ and Ca2+) represented the primary active sites for AFB1 adsorption. The position of OH– groups in cis-montmorillonites at the same side of the octahedral site enhanced AFB1 adsorption, making them more available for protonation of edge sites and subsequent interaction with AFB1. Specific characteristics of the montmorillonite in bentonites play an important role in AFB1 adsorption, although the buffer composition also affects the adsorption process significantly
Protective Effects of Curcumin and Sulforaphane Against Ionising Radiation–Induced Oxidative Stress and Inflammatory Responses in Rat Lung Tissue
No full textIonising radiation-induced lung injury is a major complication of thoracic radiotherapy, primarily driven by oxidative stress and inflammation. The current study evaluates and compares the protective effects of sulforaphane (SFN) and curcumin (CUR) pretreatment against radiation-induced oxidative damage and inflammation in rat lung tissue. Female Wistar rats were pretreated in vivo with SFN (2 mg/kg b.w./day) or CUR (4.13 mg/kg b.w./day) for 28 days per os. Isolated lung tissues were exposed ex vivo to γ-radiation (absorbed dose: 2 Gy). Oxidative stress markers—malondialdehyde (MDA), ischemia-modified albumin (IMA), total sulfhydryl (SH) groups, reduced glutathione (GSH), and superoxide dismutase (SOD)—and inflammatory markers—tumour necrosis factor alpha (TNF-α), prostaglandin-endoperoxide synthase 2 (PTGS2/COX-2), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β)—were measured to evaluate irradiation and protective effects. Radiation significantly increased MDA, TNF-α, PTGS2/COX-2, and IL-6 levels while decreasing SH groups. Pretreatment with SFN or CUR attenuated these changes. CUR showed a more pronounced effect on oxidative stress-related parameters, whereas SFN more strongly influenced inflammatory markers. These findings suggest that SFN and CUR differentially modulate radiation-induced oxidative and inflammatory responses in lung tissue under the applied experimental conditions and warrant further investigation of their potential as protective agents in radiotherapy
Efficient Removal of Ibuprofen and Diclofenac Sodium Using Modified Bentonites: Adsorption Studies and Performance in Real Water
No full textThis study investigates the adsorption of ibuprofen (IBU) and diclofenac sodium (DS) using bentonite modified with varying amounts (50, 75, and 100% of cation exchange capacity—CEC) of two surfactants: octadecyl(dimethylbenzyl)ammonium (ODMBA) chloride and hexadecyltrimethylammonium (HDTMA) bromide. The resulting organobentonites were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry/thermogravimetric analysis (DSC/TG), and zeta potential analysis. The results indicated that higher surfactant concentrations in organobentonites improved adsorption efficiencies for both drugs, while ODMBA-modified organobentonites exhibited notably larger adsorption capacities than HDTMA-modified samples. The adsorption isotherms fitted well to both the Langmuir and Freundlich models, with a better fit observed for the Freundlich model. The highest adsorption capacities were 102 mg/g for IBU and 160 mg/g for DS on sample OB-100 (organobentonite with 100% of ODMBA). Characterization of samples after drug adsorption, using FTIR, zeta potential and DSC/TG analysis, confirmed drug presence in organobentonites. Adsorption tests of DS in real river water (Danube and Sava rivers) showed that OB-100 demonstrated high removal capacity for DS. The findings suggest that organobentonites are low-cost adsorbents with potential for the removal of pharmaceutical contaminants from real aquatic environments