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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
Antigen-Specific Ganglioside Serological Profile of Pancreatic and Gastric Cancer Patients by Multiple TLC Overlay Assay and IR-MALDI Mass Spectrometry
No full textBackground: Altered glycosphingolipidome in cancerous tissues and cells reflects the circulatory glycosphingolipid (GSL) profiles, which is advantageous for establishing cancer biomarkers and/or unravelling GSL-associated mechanisms of immunity in cancer. Methods: Here, we combined a microscale extraction of GSLs with multiple overlay TLC assays and IR-MALDI-o-TOF MS and implemented it for the first time in serum analysis of CD75s-, CD15s-, and iso-CD75s-containing sialylated GSLs of ganglio- and neolacto-series. Results: This sensitive antigen-specific targeted GSL workflow enabled the identification of 80 sialylated GSLs containing the specific antigens in human sera and was applied for the investigation of clinical serum samples from gastric/stomach cancer patients (n = 40), pancreatic cancer patients (n = 40), and a cancer-free control group (n = 20). The CD75s-, CD15s-, and iso-CD75s-containing GSL series encompassing complex monosialylated and fucosylated GSLs of neolacto-series, with up to pentadecasaccharide chains, were detected in both cancer types, while differential semi-quantitative analysis indicates a tumor type-specific associated GSL profile. Both cancer types share a drop in the complex fucosylated neolacto-gangliosides during tumor progression, implying a decreased synthesis of long-chain neolacto-series. Conclusions: This drop suggesting a role of these highly polar complex ganglioside species in evading humoral tumor immune response in the early tumor stages
Stereoselective synthesis and redox properties of ferrocene-substituted pyrrolidines via [3+2] cycloaddition
No full textA new series of ferrocene-containing pyrrolidine derivatives was synthesized through a [3+2] dipolar cycloaddition of azomethine ylides with 1-ferrocenyl-2-nitroethene. Under mild conditions and in the presence of silver acetate and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), the reaction was performed repeatedly to afford six novel compounds in moderate to good yields. Structural elucidation was achieved by NMR and IR, while single-crystal X-ray diffraction of two representative compounds unambiguously confirmed the stereochemical outcome and spatial orientation of the substituents. The stereochemical preferences were rationalized by charge distribution, steric effects of the bulky ferrocene group, and secondary orbital interactions, consistent with an endo reaction pathway. According to X-ray analysis, all five substituents of the pyrrolidine ring are involved in intermolecular interactions, while a double chain composed solely of ferrocenyl units appears as the most prominent structural feature. The non-covalent interactions were analyzed based on interaction energy. Electrochemical properties were examined by cyclic voltammetry (CV), which revealed a reversible one-electron redox process. The anodic peak potentials were shifted relative to ferrocene, reflecting the influence of electron-withdrawing nitro substituents. These findings highlight the dual synthetic and biological relevance of ferrocenyl pyrrolidines as redox-active scaffolds with antioxidant potential
Development of PMMA–silica–alumina nanocomposites for enhanced performance
No full textThis study focuses on alumina–silica oxide mixtures synthesised via sol–gel processing using rice husk and aluminium chloride hydroxide as precursors followed by calcination, yielding submicron particles suitable for reinforcing poly(methyl methacrylate) (PMMA). These hybrid oxide particles exhibit a well-dispersed phase composition of alumina and silica, enhancing mechanical properties when homogeneously distributed within the brittle PMMA matrix. X-ray diffraction (XRD) confirmed the crystallinity and phase structure of the particles. The PMMA composites were formulated with 1 wt.%, 3 wt.%, and 5 wt.% Al2O3/SiO2, then analysed using scanning electron microscopy (SEM), optical microscopy, and indentation testing. Vickers microhardness and tensile tests showed significant improvements in the hardness, strength, and creep resistance of the hybrid nanocomposites. The hardness increased by approximately 25.94% and creep resistance by 4.4% when 3 wt.% of Al2O3/SiO2 particles was added to PMMA, while the tensile strength increased to approximately twice that of the pure PMMA matrix. Wettability was evaluated via sessile drop measurements using water and glycerine, representing polar liquids with differing viscosities. The surface free energy and work of adhesion were calculated using the Owens–Wendt–Rabel–Kaelble (OWRK) model. The results show that even low concentrations of hydrophilic particles markedly influence the wetting behaviour, with modular surface properties emerging as a function of filler loading. Among tested compositions, the 3 wt.% oxide-reinforced composite achieved the most favourable balance of mechanical reinforcement and wettability control, identifying it as the optimal formulation for enhanced PMMA-based dental applications
Different calculating schemes for evaluating the transition emission energies in a Cr3+-activated KMgF3 phosphor: ΔSCF-DFT approaches
No full textTo clarify excellent emission properties of a KMgF3:Cr3+ phosphor, first-principles calculations based on a density functional theory (DFT) framework have been made in the present work. It is well-known that big problems arise in DFT calculations of phosphors when embedding ions substitute ions possessing different charge states in a host matrix. Therefore, in the present work several models for calculating the electronic structure, optical transition energies and interatomic bond lengths have been developed. In particular, we employ two models to gain the charge balance in the KMgF3:Cr3+ phosphor for keeping the charge of the Cr3+ ion as “+3”. In the first model, one electron is removed from the system of total electrons, whereas in the second model, the charge of the Cr3+ ion is kept as “+3” due to formation of a fluorine vacancy. Using these models and different approaches for exchange correlation potential, we have calculated for the KMgF3:Cr3+ phosphor total and partial densities of states, peculiarities of “Cr3+-ligand” chemical bonding, and zero phonon line (ZPL) transition emission energies, (4A2 ↔ 2E)ZPL and (4A2 ↔ 4T2)ZPL. Results of the present DFT calculations indicate that inserting Cr3+ ions in the crystal lattice of KMgF3 causes the appearance of new electronic 3d states associated with Cr3+ ions: these new Cr3+ 3d states either completely locate in the energy band gap of the KMgF3:Cr3+ phosphor or partly superimpose its conduction band bottom. When going from the ground 4A2 to the exited 2E and 2E/2T1 states, the additional Cr3+ 3d t2g/Cr3+ 3d eg electronic state splitting takes place due to the Jahn-Teller effect
Eu3+-Doped Sr2LaF7 Nanopowders as Efficient Red and Deep-Red Emitters for Advanced Horticultural Lighting
No full textOur study presents Eu3 + -activated Sr2 LaF7 nanophosphors with efficient red and deep- red emission, 555% enhanced intensity, and outstanding thermal stability—ideal for next- generation plant growth light-emitting diodes (LEDs). Phosphors applied in agricultural LEDs for plant growth are designed to convert electrical energy into light within the pho- tosynthetically active radiation range, covering wavelengths from 400 to 700 nm. For that purpose, a series of Sr2 La1- x Eux F7 ( x = 0, 0.05, 0.1, 0.15, 0.2, 0.4, 0.5, 0.6, 0.8) lumines- cent nanopowders were prepared. Transmission electron microscopy shows nanoparticles of ∼33 nm size. The Sr2 LaF7 sample bandgap of 8.8 eV was determined using the reflected electron energy loss spectroscopy method. Photoluminescence measurements show highly efficient red and deep-red emission, with an optimal concentration of 50 mol% of Eu3 + , which exhibits a remarkable 555% emission enhancement compared to 5 mol% of Eu3 + . The most prominent emission peaks are around 600 nm (orange/red) and 700 nm (deep red). The observed lifetimes are long; they gradually decrease as the Eu concentration increases, from 14.9 ms for x = 0.05 to 8.3 ms for x = 0.8. Temperature-dependent luminescence spec- tra to 200◦C indicate that the optimal sample exhibits outstanding thermal stability, with emission intensity retaining 97% of its room-temperature value. The quantum efficiency of the optimized sample is 52.73%. The high emission efficiency, wide bandgap, good thermal stability, and unusual dominant 700 nm deep-red emission make these samples promising nanophosphors for LED-based indoor plant growth
Catalytic effect of conductive dyes for improved analytical performance of an electrochemical sensor for piperine determination in black pepper
No full textThe electrocatalytic properties of anionic dye-based sensors were demonstrated via their strong influence on the oxidation signal of piperine (PIP), a widely used alkaloid usually found in food and pharmaceutical samples. The purpose of this study was to improve recent advancements in the design and sensing ability of modified carbon paste electrodes (CPEs) prepared by electropolymerization of dyes for PIP determination. The important variables were the choice of dye for electropolymerization and polymer dye film thickness when incorporated onto the CPE surface, which were evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The performances of the two anionic dye-based sensors, poly(murexide)-modified CPE (PMUX/CPE) and poly(bromocresol green)-modified CPE (PBCG/CPE), were compared, and PMUX/CPE proved to show the most favorable electrocatalytic behavior. CV studies revealed that PIP undergoes an irreversible electrooxidation at the PMUX/CPE and exhibits an adsorptive behavior. Consequently, the sensitivity of the PMUX/CPE was greatly improved when polarized at −0.3 V for 60 s due to the higher accumulation ability of PIP at pH 8.0, as determined during the optimization of the square wave adsorptive stripping voltammetry (SW-AdSV) method. The achieved analytical response of PIP was found to be linear in the range of 0.067–3.47 µmol L−1 PIP, and the limit of detection was 21 nmol L−1 PIP. Ultimately, the PIP concentration in a black pepper sample was determined using the designed PMUX/CPE and the SW-AdSV method, which demonstrated great sensitivity, selectivity, and reproducibility. The obtained results were confirmed using a comparative spectrophotometric method.This is the peer-reviewed version of the article: Mutić, Sanja, Sandra Petrović, Dalibor Stanković, and Jasmina Anojčić. 2026. “Catalytic Effect of Conductive Dyes for Improved Analytical Performance of an Electrochemical Sensor for Piperine Determination in Black Pepper.” Analyst. doi:[https://doi.org/10.1039/D6AN00068A
Low Power Density Actuation of Near-infrared Light-Driven AgBiS2/mSiO2 Nanomotors
No full textPhotothermal nanomotors are hybrid nanosystems that convert incident radiation into motion. These systems possess the capability to perform tasks on small-scale objects in their vicinity in a controllable manner by manipulating the intensity and duration of the incident radiation. In the biomedical field, near-infrared (NIR) light within the wavelength range of 650 nm to 1350 nm is commonly utilized to generate propulsion due to its extensive tissue penetration depth and low phototoxicity. Several hybrid nanosystems have been proposed [1, 2] as light-driven nanomotors capable of achieving velocities exceeding 20 m/s under NIR actuation. However, reported NIR light-driven nanomotors typically operate under power densities higher than ~2 W/cm2, which is well above the safety standard for biomedical application (~0.3 W/cm2 at 808 nm). In this contribution, we report on fabrication, characterization, and mobility analyses under 808 nm NIR light excitation of hybrid nanosystems composed of silver bismuth sulfide (AgBiS2) and mesoporous silica (mSiO2). It will be shown that efficient actuation of the hybrid nanosystems can be achieved by 808 nm irradiation of power density lower than 0.6 W/cm2 . In addition, the influence of the photothermal actuation on the internalization of AgBiS2/mSiO2 nanoparticles in A375 melanoma cells will be briefly discussed.19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026
Progress report on wide bandgap oxide semiconductor device modelling
No full textWide-bandgap semiconductor materials have emerged as key candidates for electronic and optoelectronic devices operating under high power, high frequency, and harsh environmental conditions [1,2]. In this progress report, we present our recent numerical investigations of band structure and transport in wide-bandgap semiconductor devices, with a particular focus on ZnO and Ga₂O₃ material systems [3-5]. Depolarisation shift is included in the optical absorption coefficient calculations. The presented results summarise current modelling capabilities and outline future directions to improve predictive accuracy, thereby supporting the design and optimisation of wide-bandgap semiconductor devices.19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026
Dynamics of THz quantum cascade lasers under external optical feedback
No full textThe investigation of quantum cascade laser (QCL) dynamics under external optical feedback is crucial for the development of more precise QCL-based sensing and communication devices. In this theoretical contribution, we present our recent numerical results of THz frequency exemplary QCL designs [1] in which we observe different dynamical regimes arising in an external optical feedback configuration [2]. In particular, we identify transitions from single to multimode operation, appearance of frequency combs, and mixed states depending on the length of the external cavity. The parameters used in the dynamics simulations are extracted from carrier transport simulations modelled by a density matrix approach presented in [3], which uses the first neighbour and tight binding approximations, together with the infinite period QCL consideration. The relevant scattering mechanisms are described as perturbations with Fermi's golden rule, using the wavefunctions and material parameters as inputs. For modelling of the laser dynamics under external optical feedback, two approaches based on Maxwell-Bloch equations are used: (i) effective semiconductor MaxwellBloch equations [4] with current-dependent input parameters and (ii) standard Maxwell-Bloch equations in the rotating wave approximation (RWA) and the slowly varying envelope approximation (SVEA).19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026