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Assessment of petroleum-type pollutants and PAHs in soil from the eastern slopes of the “Suva Planina” Special Nature Reserve
No full textThis study investigates the molecular composition of extractable organic matter (EOM) in soil samples (8 samples) collected from the eastern slopes of Suva Planina, Serbia, with the aim of assessing the presence of petroleum-type pollutants and polycyclic aromatic hydrocarbons (PAHs). The study area was selected due to its significant ecological importance, as it is a Special Nature Reserve protected under national regulations defined by three levels of protection. Soil samples were air-dried, homogenized, and sieved through a 500 µm mesh. The organic matter was extracted using two methods: conventional Soxhlet extraction (25 hours) and ultrasonic extraction (3 × 15 minutes). The extraction solvent used in both methods was an azeotropic mixture of dichloromethane and methanol. The resulting extracts underwent saponification (KOH/methanol, 2 hours) to remove polar saponifiable lipids. The remaining extract was then separated into three fractions: aliphatic, aromatic, and polar, using column chromatography. These fractions were analyzed by gas chromatography-mass spectrometry (GC-MS). In the aliphatic fraction, n-alkanes ranging from C16 to C35 were identified, with a clear predominance of odd-numbered homologs, particularly C23–C33, and a peak at C31 in all samples, except for one where the dominant n-alkane was C29. Lower n-alkanes (≤ C20) were present in trace amounts. Additionally, trace amounts of lower even-numbered nalkenes (C16–C20) were detected. This distribution of n-alkanes, coupled with the absence of isoprenoids, pristane, phytane, steranes, diasteranes, hopanes, and tricyclic terpenes, strongly suggests that the organic matter originates from terrestrial sources, consistent with the flora of Suva Planina. The reserve is home to 1,261 plant species, including 1,232 angiosperms, 18 ferns, and 58 lichen species. The aromatic fraction was found to be negligible (0.0000 g in all samples), and no aromatic compounds typical for petroleum-type pollutants (e.g., naphthalene, phenanthrene, fluorene, methyl derivatives, tri-aromatic steranes, alkylbenzenes) were detected. Additionally, none of the 16 priority PAHs listed by the US EPA were found in the aromatic fraction. In the polar fraction, compounds typically found in native plant organic matter were identified, such as β-sitosterol, stigmasterol, α- and β-amyrin, and cholesterol. The presence of α- and β-amyrin is in agreement with the high abundance of angiosperms in the reserve, as these plants, unlike gymnosperms, synthesize pentacyclic triterpenoids with an amyrin skeleton. The results obtained from both extraction methods showed nearly identical molecular compositions of EOM, with a correlation coefficient (R²) of 0.9542 between Soxhlet and ultrasonic extraction. However, the yield of EOM was higher in the case of Soxhlet extraction, likely due to the longer extraction time. The findings indicate that the investigated site on the eastern slopes of Suva Planina is not contaminated by petroleum-type pollutants or PAHs.19th International Conference on Chemistry and the Environment - Environmental Chemistry for Sustainability : Belgrade, Serbia, June 8-12, 2025
Chromium (VI) Adsorption on Citric Acid Functionalized Cross-Linked Chitosan Beads: Comparison of Experimental Results and Results Obtained with COMSOL Multiphysics Software for Fixed-Bed System
No full textHexavalent chromium is one of the most toxic pollutant that can be found in wastewaters and can cause serious harm to environments. In this study, chitosan hydrogel beads (CHBs) and cross-linked chitosan hydrogel beads functionalized with tricarboxylic citric acid (CA-GLA-CHBs) were investigated for Cr(VI) removal, in batch and dynamic adsorption systems. Batch equilibrium experiments indicated that CA-GLA- CHBs showed almost 20% higher adsorption capacity and wider operational pH range. In a dynamic system, CA-GLA-CHBs was used as column packing material and the column dynamics was investigated at different conditions. The empirical Adams-Bohart, Thomas and Yoon-Nelson mathematical models were applied to predict the breakthrough profiles of Cr(VI) and evaluate the column parameters under different operating conditions. Finally, COMSOL Multiphysics software with implemented Advection Dispersion Reaction (ADR) equation was used as a numerical tool to simulate breakthrough curves for the applied dynamic system in order to validate the possibility of its application for process design in the scaled-up fixed-bed column systems for wastewater treatment. Simulated breakthrough curves of Cr(VI) adsorption matched well with the experimental, thus proving that COMSOL software can be used for scaling-up fixed-bed columns packed with low-cost CA- GLA-CHBs bioadsorbent.ESEV : 1st Earth Systems and Environment Journal Annual Meeting, 28-30 April 2025, Istanbul, Turkiye
Radiation-Induced Synthesis of Polymer Networks Based on Thermoresponsive Ethylene Glycol Propylene Glycol Monomers
No full textIn this paper, different poly((ethylene glycol)-(propylene glycol)) methacrylate (P(EGPG)MA) hydrogels were synthesized by gamma-radiation-induced polymerization and crosslinking from a monomer–bisolvent mixture using the following monomers: (ethylene glycol)6 methacrylate (EG6MA), ((ethylene glycol)6-(propylene glycol)3) methacrylate (EG6PG3MA), ((propylene glycol)6-(ethylene glycol)3) methacrylate (PG6EG3MA), and (propylene glycol)5 methacrylate (PG5MA), along with different water/ethanol compositions as the solvent. The monomer–bisolvent mixture was exposed to various radiation doses (5, 10, 15, 25, and 50 kGy). Considerable emphasis was placed on optimizing and tuning the reaction conditions necessary for the fabrication of methacrylic networks with pendant EGPG terminals. A further investigation was conducted on the effects of monomer composition, different preparation conditions, and radiation processing on thermal properties, microstructure, swelling behavior, and volume phase transition. Special attention was dedicated to PPG6EG3MA hydrogel, whose volume phase transition temperature is near physiological temperatures. This study identifies an optimal radiation dose and a water/ethanol solvent ratio for the synthesis of the radiation-induced hydrogels. Employing ionizing radiation within the sterilization dose range enables the simultaneous fabrication and sterilization of these hydrogels, offering an efficient production process. The findings provide new insights into the role of bisolvent composition on hydrogel formation and properties, and they present practical guidelines for optimizing hydrogel synthesis across a wide range of applications
Nutritional Modulation of Impaired Blood-Brain Barrier Integrity and Function in Major Depression
No full textMajor Depressive Disorder (MDD) is increasingly linked to disruptions in blood-brain barrier (BBB) integrity, contributing to neuroinflammation and impaired brain homeostasis. While traditional antidepressant therapies often fail to achieve full remission, growing evidence suggests that specific dietary compounds may offer novel avenues for restoring BBB function and improving mental health outcomes. This review explores the potential of selected nutrients—omega-3 fatty acids, vitamin D, sulforaphane, fucoidan, and urolithins—to modulate BBB integrity through anti-inflammatory, antioxidant, and transporter-regulatory mechanisms. These compounds act by reinforcing tight junctions, reducing matrix metalloproteinase activity, and modulating efflux transporters such as P-glycoprotein. Although current evidence is largely preclinical, the mechanistic insights provided in this review support the rationale for integrating nutritional strategies into the management of MDD. Future clinical studies are needed to validate these findings and develop biomarker-driven approaches for targeting the BBB in nutritional interventions for psychiatric disorders
Efficient Removal of Nitrobenzene and Its Compounds by Coconut Shell-Derived Activated Carbon
No full textActivated carbon prepared from coconut shell was characterized using SEM/EDS, N2-sorption, XRD analysis, Raman, and FTIR spectroscopy. It was then evaluated in terms of its capacity to adsorb nitrobenzene, a priority pollutant, from water samples with varying pH levels. Initial studies revealed high adsorption capacity; further studies were broadened to include nitrobenzene derivative, dinitrobenzene, as real samples are expected to contain a mixture of these pollutants. The maximum amount of adsorbed adsorbate increased notably with temperature, reaching 12.88 mg g−1 and 42.75 mg g−1 for nitrobenzene and dinitrobenzene, respectively, at 35 °C. Thermodynamic considerations and determined values of ∆G0 and ∆S0 indicated that the adsorption process of both nitrobenzene and dinitrobenzene is spontaneous and ∆H0 value indicated that it is endothermic in the studied temperature range. A study of the simultaneous adsorption of nitrobenzene and dinitrobenzene indicated a higher affinity toward dinitrobenzene. This study pointed out that coconut shell-derived activated carbon holds high potential as an adsorbent for removing nitrobenzene and its derivatives from water samples
Green solution for lead pollution: phytoremediation with Festuca rubra and brushite-aluminosilicate geopolymer material
No full textAluminosilicate materials are known for their high removal efficiency of lead (Pb) ions from aqueous solutions, whereas in Pb-contaminated soils they can immobilise lead ions and improve soil quality, contributing to more efficient remediation. Brushite-aluminosilicate geopolymer materials synthesised from an abandoned, raw kaolinite clay with the addition of 2, 4, and 6 wt% of brushite, were tested for their efficiency in removing Pb ions with Festuca rubra, which is known to tolerate its high concentration in soil. The highest efficiency for Pb immobilisation in the soil was observed with the addition of brushite-metakaolin-based geopolymer GPB2% and GPB6%, whereas physiological and biochemical parameters indicate a reduction in metal stress with increasing brushite content, as the concentrations of proline, total phenolic content and antioxidant activity in the shoots of the plants to which GPB6% was added were even lower than in some samples grown on uncontaminated soil. Moreover, in this sample the highest concentrations of photosynthetic pigments were found. This study suggests that the brushite-metakaolin geopolymer material improves the potential of F. rubra in remediation, whereas its stability and harmlessness to the environment, further recommend its use in the field. © 2025 Societá Botanica Italiana.This is an Accepted Manuscript version of the following article, accepted for publication in Plant Biosystems. Djukić, D., Mirković, M., Andrejić, G., Aleksić, U., Mišljenović, T., Vujičić, M., & Jakovljević, K. (2025). Green solution for lead pollution: phytoremediation with Festuca rubra and brushite-aluminosilicate geopolymer material. Plant Biosystems-An International Journal Dealing with all Aspects of Plant Biology, 1-10, available at [https://doi.org/10.1080/11263504.2025.2485975]. It is deposited under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited
Comparative experimental and DFT study of ZnO particles prepared using Reynoutria bohemica extract
No full textThe green synthetic procedure was applied to prepare zinc oxide (ZnO) using Reynoutria bohemica leaf extract. Calcination at ≥300 °C induced the formation of pyramidal, micrometer-in-size ZnO particles with pure wurtzite phase without impurities. The thermogravimetric (TG) and Furrier transmission infrared (FTIR) measurements confirmed the absence of precursor residues in the prepared samples. The isoelectric points of ZnO samples, synthesized using Reynoutria bohemica extract, lie in a more acidic region (2.7<pH<4.0) compared to ZnO particles, prepared traditionally by urea-assisted precipitation method (pH∼7.4). The green-synthesized ZnO samples prepared by Reynoutria bohemica leaf extract display absorption in the visible spectral range with absorption onset around 540 nm and pronounced green photoluminescence (PL). To support the hypothesis that oxygen vacancies induced the peculiar optical properties of green-synthesized ZnO, the density functional theory (DFT) calculations were performed using a cluster design to mimic ZnO particles with a missing O-atom from the interior. The calculated difference in energy levels between the oxygen vacancy state and the conduction band minimum (1.91 eV) agrees with the experimentally observed absorption onset in green-synthesized ZnO particles. Also, the natural bond orbital (NBO) analysis, which estimates the effect of oxygen vacancies on charge distribution, supports the shift of the isoelectric points of ZnO particles towards a more acidic region. © 202
Addressing gaps in calibration and standardization of X-ray measurement systems for medical use
No full textThe medical use of X-rays represents the largest source of artificial ionizing radiation exposure to the global
population. To ensure optimal performance and safety in imaging and interventional procedures, quality control
is commonly performed by measuring key parameters of the X-ray system, such as air kerma, tube voltage, and
half-value layer layer non-invasively from X-ray beam using X-ray multimeters (XMMs). While some parameters
benefit from established standardization and metrological support, others still lack a unified and consistent
approach. Moreover, there is a shortage of data on the performance of XMMs in varying measurement conditions.
A study was performed to assesses the existing standards and identify calibration and measurement needs by
reviewing available guidelines, conducting surveys with clinical medical physicists and calibration laboratories,
and analyzing data from the key comparison database.
Calibration services for air kerma are readily available across a broad range of radiation qualities. However,
calibration services for other key parameters are scarce, with very few laboratories—primarily manufacturers—
able to provide these services. Additionally, gaps in standardization exist, and calibration procedures for these
quantities lack harmonization. The surveys also showed that different countries have different requirements for
calibration, verification and type testing of XMMs, and that the use of calibration coefficients by medical
physicists is very sporadic.
To address these issues, the development of new calibration services with harmonized procedures for X-ray
multimeters is essential, particularly for parameters beyond air kerma. These procedures will be formulated
within the framework of the TraMeXI project and subsequently shared with standardization bodies, metrology
organizations, and the medical physics community. The project also develops procedures for clinical
measurements, including the recommendations on the use of calibration coefficients and standardized
measurement setups.International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences : May 26-30, Crete, Greece
Prospects for heart failure diagnostics using photoplethysmography
No full textHeart failure (HF) is a serious condition that affects 64 million people worldwide, has high mortality and treatment costs. As it is primarily caused by mechanical malfunction of heart, the tests used in primary care, such as ECG, do not accurately detect it. Hence, a combination of tests and clinical evaluations, including a blood test, chest X-ray, magnetic resonance, and echocardiogram as a gold standard for the assessment of ejection fraction (EF), is used, however, often too late when the condition has already progressed towards the fatal outcome. This study presents deep learning approaches for HF detection and classifying its subtypes based on simultaneous mechanical cardiac signals, with a primary focus on photoplethysmogram (PPG) due to their optical, non-invasive measurement modality. Two neural network architectures were developed: the first processes PPG, phonocardiogram (PCG), and seismocardiogram (SCG) signals independently, extracting features via convolutional and LSTM layers. The second model aligns these signals temporally by adapting their sampling frequencies through adjusted convolutional and pooling layers, enabling joint feature extraction that considers inter-signal relationships. We used an interim database from the ongoing SensSmart clinical study comprising 407 recordings from 82 subjects (46 HF patients, 36 healthy). HF patients were further categorized into three subtypes: preserved, mid-range, and reduced EF. PPG recordings, acquired at the brachial artery, alongside PCG and SCG recordings, were preprocessed and passed to the neural network models. In binary classification tasks, accuracies exceeded 73%, with sensitivities reaching up to 93%, indicating a high true positive rate in identifying pathological cases. Multiclass classification, which aimed to distinguish HF subtypes, showed accuracy around 64%. These results demonstrate the added value of using the PPG, in addition to other mechanical cardiac signals, in HF diagnostics. Importantly, all signals can be acquired via non-invasive, wearable solutions—highlighting the promise of integrating deep learning with accessible health technologies for early cardiovascular risk screening.X International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; 25 - 29 August 2025 Belgrade, Serbia
Electron energy loss function in a graphene-hBN-graphene heterostructure
No full textIn our previous publications [1-4], we studied the effects of plasmon-phonon hybridization in a sandwich-like structure consisting of two doped graphene sheets separated by a layer of aluminum oxide (Al2O3) [1-4], silicon dioxide (SiO2) [4], and hafnium dioxide (HfO2) [4]. In all those publications, we considered only isotropic insulators between two graphene sheets. In this work, we investigate for the first time two graphene layers separated by an insulating slab that exhibits anisotropy of a uniaxial crystal. We choose an anisotropic layer of hexagonal boron nitride (hBN) because van der Waals heterostructures based on graphene and hBN layers with different stacking modes have been attracting a great deal of interest in the last few years owing to their potential applications [5-8]. The objective is to explore the effects of anisotropy of hBN in the graphene-hBN-graphene heterostructure. In particular, we examine the plasmon-phonon hybridization in the range of frequencies corresponding to the Reststrahlen bands of hBN, where the phonon modes of this material exhibit hyperbolic dispersion. The expression for the effective surface electron energy loss (EEL) function (the imaginary part of the negative value of the surface response function [9]) of the graphene-hBN-graphene composite system is derived following and generalizing the continued fraction method of Ref. [10]. The response function of each graphene is obtained using the dynamic polarization function of doped graphene within the random phase approximation for its π electrons described as Dirac’s fermions. The response of the anisotropic hBN layer is described by a diagonal dielectric tensor consisting of the in-plane and axial components. We compare the effective surface EEL functions of the graphene-hBN-graphene systems in the cases of the anisotropic and fictitious isotropic (with the dielectric functions equal to the in-plane or axial components) hBN layers.X International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; 25 - 29 August 2025 Belgrade, Serbia