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Претрага радова објављених у периоду (2019-2020):
2020 |
Amić, A; Marković, Z; Marković, Dimitrić J M; Milenković, D; Stepanić, V Antioxidative potential of ferulic acid phenoxyl radical Journal Article Phytochemistry, 170 , 2020. @article{Amić2020, title = {Antioxidative potential of ferulic acid phenoxyl radical}, author = {A Amić and Z Marković and J M Dimitrić Marković and D Milenković and V Stepanić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075868348&doi=10.1016%2fj.phytochem.2019.112218&partnerID=40&md5=6076887d9f28971d3996f4d34577aa26}, doi = {10.1016/j.phytochem.2019.112218}, year = {2020}, date = {2020-01-01}, journal = {Phytochemistry}, volume = {170}, abstract = {The vast majority of previous studies dealing with antioxidant potency of (poly)phenols does not investigate the fate of phenoxyl radical obtained after single free radical scavenging. We investigated possible pathways of inactivation of ferulic acid phenoxyl radical (FAPR) using DFT method. Direct coupling with a set of 10 physiologically important free radicals, H-atom donation and dimerization were analysed by estimation of Gibbs free energy changes related to these processes. The former two processes are thermodynamically feasible to inactivate more dangerous free radicals such as hydroxyl, alkoxyl and carbon-centered radicals. Among dimerization reactions, the least energy demanding is formation of C-5−C-5 dimer of ferulic acid (FA), which has higher antiradical potency than FA itself. Obtained results reveal that FAPR, a priori considered as stable and unreactive, may contribute to the overall antioxidant activity of FA. This is a beneficial behavior, which makes FA a particularly valuable protector against oxidative stress. Hence, the contribution of phenoxyl radicals to the antioxidant activity of (poly)phenolic compounds should be taken into account, what has been scarcely considered until now. © 2019 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } The vast majority of previous studies dealing with antioxidant potency of (poly)phenols does not investigate the fate of phenoxyl radical obtained after single free radical scavenging. We investigated possible pathways of inactivation of ferulic acid phenoxyl radical (FAPR) using DFT method. Direct coupling with a set of 10 physiologically important free radicals, H-atom donation and dimerization were analysed by estimation of Gibbs free energy changes related to these processes. The former two processes are thermodynamically feasible to inactivate more dangerous free radicals such as hydroxyl, alkoxyl and carbon-centered radicals. Among dimerization reactions, the least energy demanding is formation of C-5−C-5 dimer of ferulic acid (FA), which has higher antiradical potency than FA itself. Obtained results reveal that FAPR, a priori considered as stable and unreactive, may contribute to the overall antioxidant activity of FA. This is a beneficial behavior, which makes FA a particularly valuable protector against oxidative stress. Hence, the contribution of phenoxyl radicals to the antioxidant activity of (poly)phenolic compounds should be taken into account, what has been scarcely considered until now. © 2019 Elsevier Ltd |
Kalijadis, A; Gavrilov, N; Jokić, B; Gilić, M; Krstić, A; Pašti, I; Babić, B Composition, structure and potential energy application of nitrogen doped carbon cryogels Journal Article Materials Chemistry and Physics, 239 , 2020. @article{Kalijadis2020, title = {Composition, structure and potential energy application of nitrogen doped carbon cryogels}, author = {A Kalijadis and N Gavrilov and B Jokić and M Gilić and A Krstić and I Pašti and B Babić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072025175&doi=10.1016%2fj.matchemphys.2019.122120&partnerID=40&md5=596fb20373556913e06eff7d52dffe6c}, doi = {10.1016/j.matchemphys.2019.122120}, year = {2020}, date = {2020-01-01}, journal = {Materials Chemistry and Physics}, volume = {239}, abstract = {Resorcinol–formaldehyde (RF) cryogels were synthesized by sol–gel polycondensation of resorcinol with formaldehyde and freeze-drying was carried out with t-butanol. Carbon cryogel (CC) was obtained by pyrolyzing RF cryogels in an inert atmosphere to 950 °C. Nitrogen doped CCs (CCN) were synthesized by introducing melamine into RF precursor mixture solution to obtain nitrogen concentration 2, 6 and 10 wt.%. Material was characterized by elemental analysis, nitrogen adsorption– desorption measurements, scanning electron microscopy (SEM), Raman spectroscopy, FT-IR Spectroscopy. Cyclic voltammetry (CV) was used to investigate capacitive and electrocatalytic properties. Conductivity measurement was also performed. Elemental analysis results confirmed presence of nitrogen in CCN samples in the range from 0.45 to 1.15 wt.%. Raman spectroscopy of the samples showed increase of D and G peak integrated intensity ratio (ID/IG) with nitrogen doping suggesting that the structural disorder as well as edge plane density increase, but according to similar ID/IG values for CCN samples, their share is not directly related to the amount of incorporated N. Characterization by nitrogen adsorption showed that overall specific surface and maximum mesopores are achieved in CCN sample with medium nitrogen concentration. Results of cyclic voltammetry experiments demonstrated maximum capacitance for CCN sample with smallest N wt.% indicating that narrow pore size distribution and high specific surface area are dominant factors to achieve good capacitive behavior. The relatively low doping level of nitrogen reached in CCN samples may be the reason for the incomplete reduction of oxygen to hydroxide and furthermore it turned out that presence of N in the structure of CC had a negligible effect on the otherwise relatively high conductivity of CC. © 2019 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Resorcinol–formaldehyde (RF) cryogels were synthesized by sol–gel polycondensation of resorcinol with formaldehyde and freeze-drying was carried out with t-butanol. Carbon cryogel (CC) was obtained by pyrolyzing RF cryogels in an inert atmosphere to 950 °C. Nitrogen doped CCs (CCN) were synthesized by introducing melamine into RF precursor mixture solution to obtain nitrogen concentration 2, 6 and 10 wt.%. Material was characterized by elemental analysis, nitrogen adsorption– desorption measurements, scanning electron microscopy (SEM), Raman spectroscopy, FT-IR Spectroscopy. Cyclic voltammetry (CV) was used to investigate capacitive and electrocatalytic properties. Conductivity measurement was also performed. Elemental analysis results confirmed presence of nitrogen in CCN samples in the range from 0.45 to 1.15 wt.%. Raman spectroscopy of the samples showed increase of D and G peak integrated intensity ratio (ID/IG) with nitrogen doping suggesting that the structural disorder as well as edge plane density increase, but according to similar ID/IG values for CCN samples, their share is not directly related to the amount of incorporated N. Characterization by nitrogen adsorption showed that overall specific surface and maximum mesopores are achieved in CCN sample with medium nitrogen concentration. Results of cyclic voltammetry experiments demonstrated maximum capacitance for CCN sample with smallest N wt.% indicating that narrow pore size distribution and high specific surface area are dominant factors to achieve good capacitive behavior. The relatively low doping level of nitrogen reached in CCN samples may be the reason for the incomplete reduction of oxygen to hydroxide and furthermore it turned out that presence of N in the structure of CC had a negligible effect on the otherwise relatively high conductivity of CC. © 2019 Elsevier B.V. |
Zang, L; Paven, Morère-Le M -C; Clochard, T; Porcher, A; Satour, P; Mojović, M; Vidović, M; Limami, A M; Montrichard, F Nitrate inhibits primary root growth by reducing accumulation of reactive oxygen species in the root tip in Medicago truncatula Journal Article Plant Physiology and Biochemistry, 146 , pp. 363-373, 2020. @article{Zang2020363, title = {Nitrate inhibits primary root growth by reducing accumulation of reactive oxygen species in the root tip in Medicago truncatula}, author = {L Zang and M -C Morère-Le Paven and T Clochard and A Porcher and P Satour and M Mojović and M Vidović and A M Limami and F Montrichard}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075562315&doi=10.1016%2fj.plaphy.2019.11.006&partnerID=40&md5=8ce9220ea6bedb365cdc4b0f2655e7fa}, doi = {10.1016/j.plaphy.2019.11.006}, year = {2020}, date = {2020-01-01}, journal = {Plant Physiology and Biochemistry}, volume = {146}, pages = {363-373}, abstract = {In Medicago truncatula, nitrate, acting as a signal perceived by NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER FAMILY 6.8 (MtNPF6.8), inhibits primary root growth through a reduction of root cell elongation. Since reactive oxygen species (ROS) produced and converted in root tip (O2 •− → H2O2 → •OH) have been reported to control cell elongation, the impact of nitrate on the distribution of these ROS in the primary root of M. truncatula was analyzed. We found that nitrate reduced the content of O2 •−, H2O2 and •OH in the root tip of three wild type genotypes sensitive to nitrate (R108, DZA, A17), inhibition of root growth and O2 •− accumulation being highly correlated. Nitrate also modified the capacity of R108 root tip to produce or remove ROS. The ROS content decrease observed in R108 in response to nitrate is linked to changes in peroxidase activity (EC1.11.1.7) with an increase in peroxidative activity that scavenge H2O2 and a decrease in hydroxylic activity that converts H2O2 into •OH. These changes impair the accumulation of H2O2 and then the accumulation of •OH, the species responsible for cell wall loosening and cell elongation. Accordingly, nitrate inhibitory effect was abolished by externally added H2O2 or mimicked by KI, an H2O2 scavenger. In contrast, nitrate has no effect on ROS production or removal capacities in npf6.8-2, a knockdown line insensitive to nitrate, affected in the nitrate transporter MtNPF6.8 (in R108 background) by RNAi. Altogether, our data show that ROS are mediators acting downstream of MtNPF6.8 in the nitrate signaling pathway. © 2019 Elsevier Masson SAS}, keywords = {}, pubstate = {published}, tppubtype = {article} } In Medicago truncatula, nitrate, acting as a signal perceived by NITRATE TRANSPORTER1/PEPTIDE TRANSPORTER FAMILY 6.8 (MtNPF6.8), inhibits primary root growth through a reduction of root cell elongation. Since reactive oxygen species (ROS) produced and converted in root tip (O2 •− → H2O2 → •OH) have been reported to control cell elongation, the impact of nitrate on the distribution of these ROS in the primary root of M. truncatula was analyzed. We found that nitrate reduced the content of O2 •−, H2O2 and •OH in the root tip of three wild type genotypes sensitive to nitrate (R108, DZA, A17), inhibition of root growth and O2 •− accumulation being highly correlated. Nitrate also modified the capacity of R108 root tip to produce or remove ROS. The ROS content decrease observed in R108 in response to nitrate is linked to changes in peroxidase activity (EC1.11.1.7) with an increase in peroxidative activity that scavenge H2O2 and a decrease in hydroxylic activity that converts H2O2 into •OH. These changes impair the accumulation of H2O2 and then the accumulation of •OH, the species responsible for cell wall loosening and cell elongation. Accordingly, nitrate inhibitory effect was abolished by externally added H2O2 or mimicked by KI, an H2O2 scavenger. In contrast, nitrate has no effect on ROS production or removal capacities in npf6.8-2, a knockdown line insensitive to nitrate, affected in the nitrate transporter MtNPF6.8 (in R108 background) by RNAi. Altogether, our data show that ROS are mediators acting downstream of MtNPF6.8 in the nitrate signaling pathway. © 2019 Elsevier Masson SAS |
Jovanović, Z; Mravik, Ž; Bajuk-Bogdanović, D; Jovanović, S; Marković, S; Vujković, M; Kovač, J; Vengust, D; Uskoković-Marković, S; Holclajtner-Antunović, I Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite Journal Article Carbon, 156 , pp. 166-178, 2020. @article{Jovanović2020166, title = {Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite}, author = {Z Jovanović and Ž Mravik and D Bajuk-Bogdanović and S Jovanović and S Marković and M Vujković and J Kovač and D Vengust and S Uskoković-Marković and I Holclajtner-Antunović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072633199&doi=10.1016%2fj.carbon.2019.09.072&partnerID=40&md5=accbc69d0979157430eca088dbf0954b}, doi = {10.1016/j.carbon.2019.09.072}, year = {2020}, date = {2020-01-01}, journal = {Carbon}, volume = {156}, pages = {166-178}, abstract = {In the present study we investigated the interaction between 12-tungstophosphoric acid (WPA) and graphene oxide (GO) in their nanocomposite by utilizing the loading of WPA as an intrinsic parameter for interaction tuning. The Fourier-transform infrared spectroscopy, temperature-programmed desorption, X-ray photoelectron spectroscopy, zeta-potential measurements, thermogravimetric analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy methods revealed that ∼5–13 wt% of WPA represents critical loading that separates two distinct contributions to GO-WPA interaction. This was explained by the self-limiting nature of GO-WPA interaction, initially controlled by high dispersion of WPA on GO (up to 13 wt%), that is eventually overpowered by WPA-WPA interaction as loading increases. As a result, the WPA agglomerates are being formed because of which the hybrid character of the nanocomposite diminishes, i.e., the properties of independent components start to be manifested to greater extent. The obtained results provide an important framework for considering possible outcomes in other 2D-0D systems, whose interaction is relevant both from fundamental and applicative point of view. Thus, the GO/WPA nanocomposite illustrates how the interactions between the components can be used for tuning the properties of nanocomposite as a whole. © 2019 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present study we investigated the interaction between 12-tungstophosphoric acid (WPA) and graphene oxide (GO) in their nanocomposite by utilizing the loading of WPA as an intrinsic parameter for interaction tuning. The Fourier-transform infrared spectroscopy, temperature-programmed desorption, X-ray photoelectron spectroscopy, zeta-potential measurements, thermogravimetric analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy methods revealed that ∼5–13 wt% of WPA represents critical loading that separates two distinct contributions to GO-WPA interaction. This was explained by the self-limiting nature of GO-WPA interaction, initially controlled by high dispersion of WPA on GO (up to 13 wt%), that is eventually overpowered by WPA-WPA interaction as loading increases. As a result, the WPA agglomerates are being formed because of which the hybrid character of the nanocomposite diminishes, i.e., the properties of independent components start to be manifested to greater extent. The obtained results provide an important framework for considering possible outcomes in other 2D-0D systems, whose interaction is relevant both from fundamental and applicative point of view. Thus, the GO/WPA nanocomposite illustrates how the interactions between the components can be used for tuning the properties of nanocomposite as a whole. © 2019 Elsevier Ltd |
Barudžija, T; Perović, M; Bošković, M; Cvjetićanin, N; Gyergyek, S; Mitrić, M Magnetic memory effect in hollandite-type α-KxMnO2 monocrystalline nanorods Journal Article Journal of Alloys and Compounds, 820 , 2020. @article{Barudžija2020, title = {Magnetic memory effect in hollandite-type α-KxMnO2 monocrystalline nanorods}, author = {T Barudžija and M Perović and M Bošković and N Cvjetićanin and S Gyergyek and M Mitrić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076581587&doi=10.1016%2fj.jallcom.2019.153406&partnerID=40&md5=cd13f34b01eba89fc8dbdc49ee38f795}, doi = {10.1016/j.jallcom.2019.153406}, year = {2020}, date = {2020-01-01}, journal = {Journal of Alloys and Compounds}, volume = {820}, abstract = {Memory effect due to spin-glass state below about 20 K has been illustrated in the hollandite-type α-KxMnO2 monocrystalline nanorods by systematic magnetization measurements including temperature- and time-dependent magnetization curves in low fields. In this work, we succeeded in writing, reading, and deleting 8-bits digital information in the investigated system. These results show that α-KxMnO2 is a good candidate material for a thermal memory cell. The phenomenological droplet model was used in the description of the observed memory effect, whose origin in α-KxMnO2 is associated with bulk properties, doping and frustration. © 2019 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Memory effect due to spin-glass state below about 20 K has been illustrated in the hollandite-type α-KxMnO2 monocrystalline nanorods by systematic magnetization measurements including temperature- and time-dependent magnetization curves in low fields. In this work, we succeeded in writing, reading, and deleting 8-bits digital information in the investigated system. These results show that α-KxMnO2 is a good candidate material for a thermal memory cell. The phenomenological droplet model was used in the description of the observed memory effect, whose origin in α-KxMnO2 is associated with bulk properties, doping and frustration. © 2019 Elsevier B.V. |
2019 |
Milikić, J; Stamenović, U; Vodnik, V; Ahrenkiel, S P; Šljukić, B Gold nanorod-polyaniline composites: Synthesis and evaluation as anode electrocatalysts for direct borohydride fuel cells Journal Article Electrochimica Acta, 328 , 2019. @article{Milikić2019, title = {Gold nanorod-polyaniline composites: Synthesis and evaluation as anode electrocatalysts for direct borohydride fuel cells}, author = {J Milikić and U Stamenović and V Vodnik and S P Ahrenkiel and B Šljukić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074116115&doi=10.1016%2fj.electacta.2019.135115&partnerID=40&md5=bc07c339bc6f8e670056181b108d63ce}, doi = {10.1016/j.electacta.2019.135115}, year = {2019}, date = {2019-01-01}, journal = {Electrochimica Acta}, volume = {328}, abstract = {Two gold nanorod-polyaniline (Au-PANI) composites with different contents of Au were prepared by two methods. An ex situ method, in the presence of preformed gold nanorods (AuNRs) and in situ one, when an AuNRs and PANI matrix is produced simultaneously, were used. Both methods were performed in immiscible water/toluene biphasic system as a simple interfacial polymerization process. Optical, structural and morphological characteristics of the formed nanocomposites were identified. It was found that AuNRs are embedded in the conducting emeraldine salt form of PANI. Nanocomposites containing 2.0 and 28.9 wt% of Au were subsequently systematically studied for borohydride oxidation reaction (BOR) for potential application in direct borohydride-peroxide fuel cell (DBPFC). Reaction parameters: number of electrons exchanged, order of reaction and activation energy, were evaluated. Both Au-PANI nanocomposites showed activity for BOR. A laboratory DBPFC was tested reaching specific peak power density of 184 Wg-1 at 65 °C with Au-PANI 1 nanocomposite (containing only 2.0 wt% of Au) as anode. © 2019 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Two gold nanorod-polyaniline (Au-PANI) composites with different contents of Au were prepared by two methods. An ex situ method, in the presence of preformed gold nanorods (AuNRs) and in situ one, when an AuNRs and PANI matrix is produced simultaneously, were used. Both methods were performed in immiscible water/toluene biphasic system as a simple interfacial polymerization process. Optical, structural and morphological characteristics of the formed nanocomposites were identified. It was found that AuNRs are embedded in the conducting emeraldine salt form of PANI. Nanocomposites containing 2.0 and 28.9 wt% of Au were subsequently systematically studied for borohydride oxidation reaction (BOR) for potential application in direct borohydride-peroxide fuel cell (DBPFC). Reaction parameters: number of electrons exchanged, order of reaction and activation energy, were evaluated. Both Au-PANI nanocomposites showed activity for BOR. A laboratory DBPFC was tested reaching specific peak power density of 184 Wg-1 at 65 °C with Au-PANI 1 nanocomposite (containing only 2.0 wt% of Au) as anode. © 2019 Elsevier Ltd |
Milovanović, B; Milovanović, M; Veličković, S; Veljković, F; Perić-Grujić, A; Jerosimić, S Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n = 2–6) clusters Journal Article International Journal of Quantum Chemistry, 119 (22), 2019. @article{Milovanović2019, title = {Theoretical and experimental investigation of geometry and stability of small potassium-iodide KnI (n = 2–6) clusters}, author = {B Milovanović and M Milovanović and S Veličković and F Veljković and A Perić-Grujić and S Jerosimić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068027257&doi=10.1002%2fqua.26009&partnerID=40&md5=2f44250aec1fe5844bcb42f4231ec77d}, doi = {10.1002/qua.26009}, year = {2019}, date = {2019-01-01}, journal = {International Journal of Quantum Chemistry}, volume = {119}, number = {22}, abstract = {Small heterogeneous potassium-iodide clusters are investigated by means of ab initio electronic structural methods together with experimental production and detection in mass spectrometry. Experiments were done by using Knudsen cell mass spectrometry (KCMS) modification method, which provided simultaneous generating of all KnI0,+1 (n = 2–6) clusters at once. Clusters with more than two potassium atoms are produced for the first time. The lowest lying isomers of those KnI0,+1 (n = 2–6) clusters were found by using a random-kick procedure. The best description of growth of these clusters is the addition of one potassium atom to a smaller-neighbor cluster. Subsequently, stability of these species was examined. In spite of general trend of decreasing of binding energies, the closed-shell species have slightly larger stability with respect to the open-shell species. Alternation of dissociation energies between closed-shell and open-shell clusters is presented. Experimental setup also allows determination of ionization energies of clusters: the obtained values are in the range of 3.46–3.98 eV, which classify these clusters as “superalkali.” For closed-shell clusters, the theoretical adiabatic ionization energies are close to experimental values, whereas in the case of open-shell clusters, the vertical ionization energies are those that are close to experimental values. © 2019 Wiley Periodicals, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Small heterogeneous potassium-iodide clusters are investigated by means of ab initio electronic structural methods together with experimental production and detection in mass spectrometry. Experiments were done by using Knudsen cell mass spectrometry (KCMS) modification method, which provided simultaneous generating of all KnI0,+1 (n = 2–6) clusters at once. Clusters with more than two potassium atoms are produced for the first time. The lowest lying isomers of those KnI0,+1 (n = 2–6) clusters were found by using a random-kick procedure. The best description of growth of these clusters is the addition of one potassium atom to a smaller-neighbor cluster. Subsequently, stability of these species was examined. In spite of general trend of decreasing of binding energies, the closed-shell species have slightly larger stability with respect to the open-shell species. Alternation of dissociation energies between closed-shell and open-shell clusters is presented. Experimental setup also allows determination of ionization energies of clusters: the obtained values are in the range of 3.46–3.98 eV, which classify these clusters as “superalkali.” For closed-shell clusters, the theoretical adiabatic ionization energies are close to experimental values, whereas in the case of open-shell clusters, the vertical ionization energies are those that are close to experimental values. © 2019 Wiley Periodicals, Inc. |
Milovanović, B; Stanković, I M; Petković, M; Etinski, M Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution Journal Article ChemPhysChem, 20 (21), pp. 2852-2859, 2019. @article{Milovanović20192852, title = {Elucidating Solvent Effects on Strong Intramolecular Hydrogen Bond: DFT-MD Study of Dibenzoylmethane in Methanol Solution}, author = {B Milovanović and I M Stanković and M Petković and M Etinski}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074412934&doi=10.1002%2fcphc.201900704&partnerID=40&md5=5392c1ffd998a94a11d41559720dd8cb}, doi = {10.1002/cphc.201900704}, year = {2019}, date = {2019-01-01}, journal = {ChemPhysChem}, volume = {20}, number = {21}, pages = {2852-2859}, abstract = {The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen-bonded proton transfer barriers. Previous studies pointed out that solvent-solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O−H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory-based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane-methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim}, keywords = {}, pubstate = {published}, tppubtype = {article} } The dynamic aspect of solvation plays a crucial role in determining properties of strong intramolecular hydrogen bonds since solvent fluctuations modify instantaneous hydrogen-bonded proton transfer barriers. Previous studies pointed out that solvent-solute interactions in the first solvation shell govern the position of the proton but the ability of the electric field due to other solvent molecules to localize the proton remains an important issue. In this work, we examine the structure of the O−H⋅⋅⋅O intramolecular hydrogen bond of dibenzoylmethane in methanol solution by employing density functional theory-based molecular dynamics and quantum chemical calculations. Our computations showed that homogeneous electric fields with intensities corresponding to those found in polar solvents are able to considerably alter the proton transfer barrier height in the gas phase. In methanol solution, the proton position is correlated with the difference in electrostatic potentials on the oxygen atoms of dibenzoylmethane even when dibenzoylmethane-methanol hydrogen bonding is lacking. On a timescale of our simulation, the hydrogen bonding and solvent electrostatics tend to localize the proton on different oxygen atoms. These findings provide an insight into the importance of the solvent electric field on the structure of a strong intramolecular hydrogen bond. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim |
Stankovic, B; Jovanovic, J; Adnadjevic, B Application of logistic function to describe kinetics of non-isothermal dehydroxylation of fullerol Journal Article Journal of Thermal Analysis and Calorimetry, 138 (3), pp. 2295-2303, 2019. @article{Stankovic20192295, title = {Application of logistic function to describe kinetics of non-isothermal dehydroxylation of fullerol}, author = {B Stankovic and J Jovanovic and B Adnadjevic}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064461954&doi=10.1007%2fs10973-019-08222-8&partnerID=40&md5=787edde629ed837345198296814e6335}, doi = {10.1007/s10973-019-08222-8}, year = {2019}, date = {2019-01-01}, journal = {Journal of Thermal Analysis and Calorimetry}, volume = {138}, number = {3}, pages = {2295-2303}, abstract = {A sample of fullerol C60(OH)24 was synthesized. The basic physicochemical characterization of the synthesized fullerol was done. The non-isothermal kinetics of C60(OH)24 dehydroxylation has been investigated. The thermogravimetric curves have been recorded at different heating rates ranging from 5 to 25 K min−1. By application of the Kissinger–Akahira–Sunose isoconversion method, it was found that the activation energy complexly changes with the dehydroxylation degree. The possibility of mathematical description of the kinetics of fullerol dehydroxylation by logistic function was investigated. Fullerol dehydroxylation conversion curves were completely mathematically described by the linear combination of two logistic functions at all of the investigated heating rates. The changes in the values of parameters of logistic functions with heating rate were established. It was shown that complex kinetics of C60(OH)24 dehydroxylation consists of two consecutive dehydroxylation reactions (low-temperature and high-temperature components). The values of the kinetic parameters for two components of dehydroxylation process were calculated. A model for fullerol dehydroxylation has been discussed. © 2019, Akadémiai Kiadó, Budapest, Hungary.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A sample of fullerol C60(OH)24 was synthesized. The basic physicochemical characterization of the synthesized fullerol was done. The non-isothermal kinetics of C60(OH)24 dehydroxylation has been investigated. The thermogravimetric curves have been recorded at different heating rates ranging from 5 to 25 K min−1. By application of the Kissinger–Akahira–Sunose isoconversion method, it was found that the activation energy complexly changes with the dehydroxylation degree. The possibility of mathematical description of the kinetics of fullerol dehydroxylation by logistic function was investigated. Fullerol dehydroxylation conversion curves were completely mathematically described by the linear combination of two logistic functions at all of the investigated heating rates. The changes in the values of parameters of logistic functions with heating rate were established. It was shown that complex kinetics of C60(OH)24 dehydroxylation consists of two consecutive dehydroxylation reactions (low-temperature and high-temperature components). The values of the kinetic parameters for two components of dehydroxylation process were calculated. A model for fullerol dehydroxylation has been discussed. © 2019, Akadémiai Kiadó, Budapest, Hungary. |
Mišurović, J; Mojović, M; Marjanović, B; Vulić, P; Ćirić-Marjanović, G Magnetite nanoparticles-catalysed synthesis of conductive polyaniline Journal Article Synthetic Metals, 257 , 2019. @article{Mišurović2019, title = {Magnetite nanoparticles-catalysed synthesis of conductive polyaniline}, author = {J Mišurović and M Mojović and B Marjanović and P Vulić and G Ćirić-Marjanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072565581&doi=10.1016%2fj.synthmet.2019.116174&partnerID=40&md5=92bb2ed38ff6e8a6b54636036aa5a80a}, doi = {10.1016/j.synthmet.2019.116174}, year = {2019}, date = {2019-01-01}, journal = {Synthetic Metals}, volume = {257}, abstract = {Nowadays, there is a growing interest to find environmentally-friendly, simple and economical routes for the synthesis of polyaniline (PANI), one of the most important conducting polymers. For the oxidative polymerization approach hydrogen peroxide (H2O2) is highly recommended oxidant due to ecological aspects, since the product of its reduction is only water. However, its usage as an oxidant, aimed to produce conductive PANI with reasonable reaction rate, needs a catalyst. Here we report the preparation of conductive PANI in good yield by the oxidative polymerization of aniline using magnetite nanoparticles (Fe3O4 NPs) as a catalyst and H2O2 as an oxidant, with added very small amount of ammonium peroxydisulfate as the initiator. Synthesized Fe3O4 NPs (size 10–50 nm) were characterized by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). It was found that without Fe3O4 NPs, under otherwise same conditions, the reaction product is not PANI. The effect of mass ratio Fe3O4 NPs/aniline and polymerization time on the structure and physicochemical properties of prepared PANI was studied by various techniques. FTIR, Raman, UV–vis-NIR and electrical conductivity measurements confirmed the existence of conducting emeraldine salt form of PANI. XRPD revealed unchanged crystalline structure of Fe3O4 NPs upon polymerization and semi-crystalline structure of PANI. EPR spectra showed peaks assigned to PANI and Fe3O4 NPs. Described simple, environmentally improved synthetic route opens possibilities for the syntheses of conductive PANI-like polymers from other aromatic amines by using environmentally-friendly oxidant H2O2 and Fe3O4 NPs catalyst which can replace more expensive catalysts such as peroxidase enzymes. © 2019 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nowadays, there is a growing interest to find environmentally-friendly, simple and economical routes for the synthesis of polyaniline (PANI), one of the most important conducting polymers. For the oxidative polymerization approach hydrogen peroxide (H2O2) is highly recommended oxidant due to ecological aspects, since the product of its reduction is only water. However, its usage as an oxidant, aimed to produce conductive PANI with reasonable reaction rate, needs a catalyst. Here we report the preparation of conductive PANI in good yield by the oxidative polymerization of aniline using magnetite nanoparticles (Fe3O4 NPs) as a catalyst and H2O2 as an oxidant, with added very small amount of ammonium peroxydisulfate as the initiator. Synthesized Fe3O4 NPs (size 10–50 nm) were characterized by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). It was found that without Fe3O4 NPs, under otherwise same conditions, the reaction product is not PANI. The effect of mass ratio Fe3O4 NPs/aniline and polymerization time on the structure and physicochemical properties of prepared PANI was studied by various techniques. FTIR, Raman, UV–vis-NIR and electrical conductivity measurements confirmed the existence of conducting emeraldine salt form of PANI. XRPD revealed unchanged crystalline structure of Fe3O4 NPs upon polymerization and semi-crystalline structure of PANI. EPR spectra showed peaks assigned to PANI and Fe3O4 NPs. Described simple, environmentally improved synthetic route opens possibilities for the syntheses of conductive PANI-like polymers from other aromatic amines by using environmentally-friendly oxidant H2O2 and Fe3O4 NPs catalyst which can replace more expensive catalysts such as peroxidase enzymes. © 2019 Elsevier B.V. |
Todorović, M N; Radenković, M B; Rajšić, S F; Ignjatović, L M Evaluation of mortality attributed to air pollution in the three most populated cities in Serbia Journal Article International Journal of Environmental Science and Technology, 16 (11), pp. 7059-7070, 2019. @article{Todorović20197059, title = {Evaluation of mortality attributed to air pollution in the three most populated cities in Serbia}, author = {M N Todorović and M B Radenković and S F Rajšić and L M Ignjatović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064912221&doi=10.1007%2fs13762-019-02384-6&partnerID=40&md5=556435dd257ae044b65e52b73754b85c}, doi = {10.1007/s13762-019-02384-6}, year = {2019}, date = {2019-01-01}, journal = {International Journal of Environmental Science and Technology}, volume = {16}, number = {11}, pages = {7059-7070}, abstract = {The subject of this study was a mid-term evaluation of cardiovascular, respiratory and total non-accidental mortalities attributed to exposure to PM10, O3, NO2 and SO2 in the cities of Belgrade, Novi Sad and Nis, representing about 25% of the population of Serbia. The analysis was performed using AirQ+ modelling, by linking annual baseline mortality rates and daily pollutant exposure levels in 2011–2015 based on the cause-specific concentration–response functions. Estimated shares of annual mortality attributed to these pollutants, thanks to harmonizing of assessment methodologies, may stand next to and be compared with results obtained in previously conducted studies. The obtained premature deaths estimated within 95% confidence interval (in parentheses) and attributed to PM10, O3, NO2 and SO2 exposure were 2013 (1344–2677), 1411 (685–2086), 831 (555–1107) and 443 (333–530), respectively. Total non-accidental mortalities due to O3 and NO2 exposure were in the range of findings for other regions, while mortalities attributed to PM10 were higher. It was also found that cardiovascular mortality caused by these four pollutants was higher than respiratory mortality. Based on our results, efficient implementation of abatement strategies that would reduce PM10, O3 and SO2 concentrations to daily air quality limit values set by the World Health Organization could respectively prevent, in the three cities together, about 233 (156–310), 40 (19–59) and 71 (53–85) premature deaths per year. © 2019, Islamic Azad University (IAU).}, keywords = {}, pubstate = {published}, tppubtype = {article} } The subject of this study was a mid-term evaluation of cardiovascular, respiratory and total non-accidental mortalities attributed to exposure to PM10, O3, NO2 and SO2 in the cities of Belgrade, Novi Sad and Nis, representing about 25% of the population of Serbia. The analysis was performed using AirQ+ modelling, by linking annual baseline mortality rates and daily pollutant exposure levels in 2011–2015 based on the cause-specific concentration–response functions. Estimated shares of annual mortality attributed to these pollutants, thanks to harmonizing of assessment methodologies, may stand next to and be compared with results obtained in previously conducted studies. The obtained premature deaths estimated within 95% confidence interval (in parentheses) and attributed to PM10, O3, NO2 and SO2 exposure were 2013 (1344–2677), 1411 (685–2086), 831 (555–1107) and 443 (333–530), respectively. Total non-accidental mortalities due to O3 and NO2 exposure were in the range of findings for other regions, while mortalities attributed to PM10 were higher. It was also found that cardiovascular mortality caused by these four pollutants was higher than respiratory mortality. Based on our results, efficient implementation of abatement strategies that would reduce PM10, O3 and SO2 concentrations to daily air quality limit values set by the World Health Organization could respectively prevent, in the three cities together, about 233 (156–310), 40 (19–59) and 71 (53–85) premature deaths per year. © 2019, Islamic Azad University (IAU). |
Vraneš, M; Cvjetićanin, N; Papović, S; Pavlović, M; Szilágyi, I; Gadžurić, S Ionics, 25 (11), pp. 5501-5513, 2019. @article{Vraneš20195501, title = {Electrochemical study of anatase TiO2 nanotube array electrode in electrolyte based on 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid}, author = {M Vraneš and N Cvjetićanin and S Papović and M Pavlović and I Szilágyi and S Gadžurić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068135448&doi=10.1007%2fs11581-019-03129-8&partnerID=40&md5=97429ef1773fa74c2d1e3df8c28ee48a}, doi = {10.1007/s11581-019-03129-8}, year = {2019}, date = {2019-01-01}, journal = {Ionics}, volume = {25}, number = {11}, pages = {5501-5513}, abstract = {The density, viscosity and electrical conductivity of ionic liquid 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide, (C2C2imTFSI), and 0.5-M solution of LiTFSI in C2C2imTFSI were determined at different temperatures. The LiTFSI/C2C2imTFSI system was tested as a possible electrolyte for lithium-ion batteries by using anatase TiO2 nanotube array electrode as anode material for the first time. The electrochemical testing has shown not only the improvement of lithium-ion insertion/deinsertion properties by increasing temperature but also the existence of a decomposition of the electrolyte, detecting the change of colour. The decomposition of electrolyte leads to the formation of a film on the surface of the electrode which improves Coulombic efficiency during cycling. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The density, viscosity and electrical conductivity of ionic liquid 1,3-diethylimidazolium bis(trifluoromethylsulfonyl)imide, (C2C2imTFSI), and 0.5-M solution of LiTFSI in C2C2imTFSI were determined at different temperatures. The LiTFSI/C2C2imTFSI system was tested as a possible electrolyte for lithium-ion batteries by using anatase TiO2 nanotube array electrode as anode material for the first time. The electrochemical testing has shown not only the improvement of lithium-ion insertion/deinsertion properties by increasing temperature but also the existence of a decomposition of the electrolyte, detecting the change of colour. The decomposition of electrolyte leads to the formation of a film on the surface of the electrode which improves Coulombic efficiency during cycling. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. |
Stejskal, J; Acharya, U; Bober, P; Hajná, M; Trchová, M; Mičušík, M; Omastová, M; Pašti, I; Gavrilov, N Surface modification of tungsten disulfide with polypyrrole for enhancement of the conductivity and its impact on hydrogen evolution reaction Journal Article Applied Surface Science, 492 , pp. 497-503, 2019. @article{Stejskal2019497, title = {Surface modification of tungsten disulfide with polypyrrole for enhancement of the conductivity and its impact on hydrogen evolution reaction}, author = {J Stejskal and U Acharya and P Bober and M Hajná and M Trchová and M Mičušík and M Omastová and I Pašti and N Gavrilov}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068207817&doi=10.1016%2fj.apsusc.2019.06.175&partnerID=40&md5=0a48102f574313f53844bb4cd935d4a5}, doi = {10.1016/j.apsusc.2019.06.175}, year = {2019}, date = {2019-01-01}, journal = {Applied Surface Science}, volume = {492}, pages = {497-503}, abstract = {A conducting polymer, polypyrrole, was deposited on tungsten disulfide flakes in situ during the oxidation of pyrrole. The conductivity of composites exceeded the conductivities of the parent components. This synergistic effect is explained by the deposition of more conducting ordered polypyrrole at first, and less conducting globular polypyrrole later after the whole available tungsten disulfide surface was coated. Such scenario was confirmed by electron microscopies. Raman and X-ray photoelectron spectroscopies proved the completeness of the coating. Despite the increase in the conductivity, the electrocatalysis of hydrogen evolution reaction on tungsten disulfide was reduced after polypyrrole deposition, confirming also effective coating of the substrate. A simple mixture of both components, however, improved the electrocatalytic effect compared with the composite or any of its components. © 2019 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A conducting polymer, polypyrrole, was deposited on tungsten disulfide flakes in situ during the oxidation of pyrrole. The conductivity of composites exceeded the conductivities of the parent components. This synergistic effect is explained by the deposition of more conducting ordered polypyrrole at first, and less conducting globular polypyrrole later after the whole available tungsten disulfide surface was coated. Such scenario was confirmed by electron microscopies. Raman and X-ray photoelectron spectroscopies proved the completeness of the coating. Despite the increase in the conductivity, the electrocatalysis of hydrogen evolution reaction on tungsten disulfide was reduced after polypyrrole deposition, confirming also effective coating of the substrate. A simple mixture of both components, however, improved the electrocatalytic effect compared with the composite or any of its components. © 2019 Elsevier B.V. |
Rafailović, L D; Gammer, C; Ebner, C; Rentenberger, C; Jovanović, A Z; Pašti, I A; Skorodumova, N V; Karnthaler, Peter H High density of genuine growth twins in electrodeposited aluminum Journal Article Science Advances, 5 (10), 2019. @article{Rafailović2019, title = {High density of genuine growth twins in electrodeposited aluminum}, author = {L D Rafailović and C Gammer and C Ebner and C Rentenberger and A Z Jovanović and I A Pašti and N V Skorodumova and H Peter Karnthaler}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073878959&doi=10.1126%2fsciadv.aax3894&partnerID=40&md5=52c74a17024b13f3800adaa63bff7f49}, doi = {10.1126/sciadv.aax3894}, year = {2019}, date = {2019-01-01}, journal = {Science Advances}, volume = {5}, number = {10}, abstract = {We demonstrate electrodeposition as a synthesis method for fabrication of Al coatings, up to 10 m thick, containing a high density of genuine growth twins. This has not been expected since the twin boundary energy of pure Al is very high. TEM methods were used to analyze deposited Al and its nanoscaled twins. DFT methods confirmed that the influence of the substrate is limited to the layers close to the interface. Our findings are different from those achieved by sputtering of Al coatings restricted to a thickness less than 100 nm with twins dominated by epitaxial effects. We propose that in the case of electrodeposition, a high density of twins arises because of fast nucleation and is additionally promoted by a monolayer of adsorbed hydrogen originating from water impurities. Therefore, electrodeposition is a viable approach for tailoring the structure and properties of thicker, deposited Al coatings reinforced by twins. Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).}, keywords = {}, pubstate = {published}, tppubtype = {article} } We demonstrate electrodeposition as a synthesis method for fabrication of Al coatings, up to 10 m thick, containing a high density of genuine growth twins. This has not been expected since the twin boundary energy of pure Al is very high. TEM methods were used to analyze deposited Al and its nanoscaled twins. DFT methods confirmed that the influence of the substrate is limited to the layers close to the interface. Our findings are different from those achieved by sputtering of Al coatings restricted to a thickness less than 100 nm with twins dominated by epitaxial effects. We propose that in the case of electrodeposition, a high density of twins arises because of fast nucleation and is additionally promoted by a monolayer of adsorbed hydrogen originating from water impurities. Therefore, electrodeposition is a viable approach for tailoring the structure and properties of thicker, deposited Al coatings reinforced by twins. Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY). |
Holclajtner-Antunović, I; Uskoković-Marković, S; Popa, A; Jevremović, A; Vasiljević, Nedić B; Milojević-Rakić, M; Bajuk-Bogdanović, D Ethanol dehydration over Keggin type tungstophosphoric acid and its potassium salts supported on carbon Journal Article Reaction Kinetics, Mechanisms and Catalysis, 128 (1), pp. 121-137, 2019. @article{Holclajtner-Antunović2019121, title = {Ethanol dehydration over Keggin type tungstophosphoric acid and its potassium salts supported on carbon}, author = {I Holclajtner-Antunović and S Uskoković-Marković and A Popa and A Jevremović and B Nedić Vasiljević and M Milojević-Rakić and D Bajuk-Bogdanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068187891&doi=10.1007%2fs11144-019-01625-6&partnerID=40&md5=cdd0694c4a224fa6491bc76e89aa34af}, doi = {10.1007/s11144-019-01625-6}, year = {2019}, date = {2019-01-01}, journal = {Reaction Kinetics, Mechanisms and Catalysis}, volume = {128}, number = {1}, pages = {121-137}, abstract = {The current study reports the synthesis, characterization and catalytic activity of tungstophosphoric acid (HPW) and its potassium salts (KH2PW and K3PW) supported on activated carbon (AC). Because potassium salts of tungstophosphoric acid are insoluble, the carbon supported KH2PW and K3PW were prepared by a two step impregnation method. The synthesized catalysts were characterized by various physicochemical methods such as Fourier transform infrared and Raman spectroscopy, differential thermal analysis, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and nitrogen physisorption. It is observed that all active phases keep their Keggin-type structure after being supported on AC, while their specific surface area is considerably increased by deposition on this porous substrate. The results also indicated that the synthesized materials retained the morphology specific for the support as well as its thermal properties. The adsorption behaviour of the nanocomposites towards nicosulfuron pesticide was found to be particulary good and even slightly improved when compared to pure activated carbon. The catalytic activity of the prepared catalysts was probed for the vapor phase dehydration of ethanol at 300 °C. The conversion of ethanol and selectivity toward ethylene and diethyl ether of nanocomposites were compared with the values of bare HPW, KH2PW and K3PW. Results revealed that catalytic activity depends on the catalyst type and active phase loading. The conversion over unsupported catalysts decreased by increasing the cation content per Keggin unit. The nanocomposites with 30 wt% loading of HPW achieved the best conversion of nearly 100% and the highest and stable selectivity toward ethylene. The catalytic activity of nanocomposites with acidic KH2PW showed lower catalytic activity of about 70%, while the nanocomposites of neutral K3PW and AC showed negligible activity. © 2019, Akadémiai Kiadó, Budapest, Hungary.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The current study reports the synthesis, characterization and catalytic activity of tungstophosphoric acid (HPW) and its potassium salts (KH2PW and K3PW) supported on activated carbon (AC). Because potassium salts of tungstophosphoric acid are insoluble, the carbon supported KH2PW and K3PW were prepared by a two step impregnation method. The synthesized catalysts were characterized by various physicochemical methods such as Fourier transform infrared and Raman spectroscopy, differential thermal analysis, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy and nitrogen physisorption. It is observed that all active phases keep their Keggin-type structure after being supported on AC, while their specific surface area is considerably increased by deposition on this porous substrate. The results also indicated that the synthesized materials retained the morphology specific for the support as well as its thermal properties. The adsorption behaviour of the nanocomposites towards nicosulfuron pesticide was found to be particulary good and even slightly improved when compared to pure activated carbon. The catalytic activity of the prepared catalysts was probed for the vapor phase dehydration of ethanol at 300 °C. The conversion of ethanol and selectivity toward ethylene and diethyl ether of nanocomposites were compared with the values of bare HPW, KH2PW and K3PW. Results revealed that catalytic activity depends on the catalyst type and active phase loading. The conversion over unsupported catalysts decreased by increasing the cation content per Keggin unit. The nanocomposites with 30 wt% loading of HPW achieved the best conversion of nearly 100% and the highest and stable selectivity toward ethylene. The catalytic activity of nanocomposites with acidic KH2PW showed lower catalytic activity of about 70%, while the nanocomposites of neutral K3PW and AC showed negligible activity. © 2019, Akadémiai Kiadó, Budapest, Hungary. |
Petrusic, I; Dakovic, M; Zidverc-Trajkovic, J Subcortical volume changes in migraine with aura Journal Article Journal of Clinical Neurology (Korea), 15 (4), pp. 448-453, 2019. @article{Petrusic2019448, title = {Subcortical volume changes in migraine with aura}, author = {I Petrusic and M Dakovic and J Zidverc-Trajkovic}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073543111&doi=10.3988%2fjcn.2019.15.4.448&partnerID=40&md5=55f3cea2f6a32cfc39153a732df116a2}, doi = {10.3988/jcn.2019.15.4.448}, year = {2019}, date = {2019-01-01}, journal = {Journal of Clinical Neurology (Korea)}, volume = {15}, number = {4}, pages = {448-453}, abstract = {Background and Purpose Various features of the cerebral cortex and white matter have been extensively investigated in migraine with aura (MwA), but the morphological characteristics of subcortical structures have been largely neglected. The aim of this study was to identify possible differences in subcortical structures between MwA patients and healthy subjects (HS), and also to determine the correlations between the characteristics of migraine aura and the volumes of subcortical structures. Methods Thirty-two MwA patients and 32 HS matched by sex and age were analyzed in this study. Regional subcortical brain volumes were automatically calculated using the FSL/FMRIB Image Registration and Segmentation Tool software (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Glos-sary). A general linear model analysis was used to investigate differences in the volume of subcortical structures between the MwA patients and HS. A partial correlation test was used to assess correlations between the volume of subcortical structures and characteristics of MwA. Results The volumes of the right globus pallidus, left globus pallidus, and left putamen were significantly smaller in MwA patients than in HS (mean±SD): 1,427±135 mm3 vs. 1,557± 136 mm3 (p<0.001), 1,436±126 mm3 vs. 1,550±139 mm3 (p=0.001), and 4,235±437 mm3 vs. 4,522±412 mm3 (p=0.006), respectively. There were no significant relationships between subcortical structures and clinical parameters. Conclusions These findings suggest that both the globus pallidi and left putamen play significant roles in the pathophysiology of the MwA. Future studies should determine the cause-and-ef-fect relationships, since these could not be discriminated in this study due to its cross-sectional design. © 2019 Korean Neurological Association.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Background and Purpose Various features of the cerebral cortex and white matter have been extensively investigated in migraine with aura (MwA), but the morphological characteristics of subcortical structures have been largely neglected. The aim of this study was to identify possible differences in subcortical structures between MwA patients and healthy subjects (HS), and also to determine the correlations between the characteristics of migraine aura and the volumes of subcortical structures. Methods Thirty-two MwA patients and 32 HS matched by sex and age were analyzed in this study. Regional subcortical brain volumes were automatically calculated using the FSL/FMRIB Image Registration and Segmentation Tool software (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Glos-sary). A general linear model analysis was used to investigate differences in the volume of subcortical structures between the MwA patients and HS. A partial correlation test was used to assess correlations between the volume of subcortical structures and characteristics of MwA. Results The volumes of the right globus pallidus, left globus pallidus, and left putamen were significantly smaller in MwA patients than in HS (mean±SD): 1,427±135 mm3 vs. 1,557± 136 mm3 (p<0.001), 1,436±126 mm3 vs. 1,550±139 mm3 (p=0.001), and 4,235±437 mm3 vs. 4,522±412 mm3 (p=0.006), respectively. There were no significant relationships between subcortical structures and clinical parameters. Conclusions These findings suggest that both the globus pallidi and left putamen play significant roles in the pathophysiology of the MwA. Future studies should determine the cause-and-ef-fect relationships, since these could not be discriminated in this study due to its cross-sectional design. © 2019 Korean Neurological Association. |
Jevremović, A; Bober, P; Mičušík, M; Kuliček, J; Acharya, U; Pfleger, J; Milojević-Rakić, M; Krajišnik, D; Trchová, M; Stejskal, J; Ćirić-Marjanović, G Synthesis and characterization of polyaniline/BEA zeolite composites and their application in nicosulfuron adsorption Journal Article Microporous and Mesoporous Materials, 287 , pp. 234-245, 2019. @article{Jevremović2019234, title = {Synthesis and characterization of polyaniline/BEA zeolite composites and their application in nicosulfuron adsorption}, author = {A Jevremović and P Bober and M Mičušík and J Kuliček and U Acharya and J Pfleger and M Milojević-Rakić and D Krajišnik and M Trchová and J Stejskal and G Ćirić-Marjanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067290193&doi=10.1016%2fj.micromeso.2019.06.006&partnerID=40&md5=976469b19b59edf39e9860a23144ed70}, doi = {10.1016/j.micromeso.2019.06.006}, year = {2019}, date = {2019-01-01}, journal = {Microporous and Mesoporous Materials}, volume = {287}, pages = {234-245}, abstract = {Composite materials of BEA zeolite and polyaniline (PANI) were prepared by the chemical oxidative polymerization of aniline in the presence of zeolite in water (without added acid) and in an aqueous solution of sulfuric acid, using ammonium peroxydisulfate as an oxidant. Protonated (as-synthesized) and deprotonated forms of the composites and pristine PANIs were characterized by scanning electron microscopy, conductivity and zeta potential measurements, FTIR, Raman and XPS spectroscopies, and thermogravimetric analysis. Adsorption properties of synthesized materials for removal of nicosulfuron pesticide from aqueous solutions were studied, using HPLC technique. The obtained adsorption isotherms were analyzed using Freundlich and Langmuir-Freundlich equations. Protonated PANI/BEA composites showed excellent adsorption capacity (18.4–25.4 mg g−1), that was higher than the adsorption capacity of pristine BEA zeolite (18.2 mg g−1) but slightly less than neat PANI. Among PANIs, the highest adsorption capacity of 29.8 mg g−1 of adsorbent was found for protonated PANI prepared in sulfuric acid solution. Analysis of adsorption isotherms revealed high degree of surface homogeneity for all prepared composite materials and PANIs. Proposed mechanism for enhanced adsorption of nicosulfuron on protonated composites is based on hydrogen bonding of nicosulfuron O- and N-containing groups with bridging hydroxyls of BEA zeolite and –NH/ = NH+/−NH•+ groups in protonated emeraldine salt form of PANI chains (PANI-ES), accompanied with electrostatic attractive interaction between anionic nicosulfuron species and positive = NH+/−NH•+ groups in bipolaron/polaron containing structures of PANI-ES. Presence of protons in bridging hydroxyls in BEA zeolite and in protonated PANI-ES chains is essential for excellent adsorption of nicosulfuron via hydrogen bonding on all protonated composite samples. In support of this interpretation, deprotonated PANI/BEA composites and deprotonated PANIs showed significantly lower adsorption capacities (in the range 5.5–13.0 mg g−1) compared to those of their protonated counterparts. © 2019 Elsevier Inc.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Composite materials of BEA zeolite and polyaniline (PANI) were prepared by the chemical oxidative polymerization of aniline in the presence of zeolite in water (without added acid) and in an aqueous solution of sulfuric acid, using ammonium peroxydisulfate as an oxidant. Protonated (as-synthesized) and deprotonated forms of the composites and pristine PANIs were characterized by scanning electron microscopy, conductivity and zeta potential measurements, FTIR, Raman and XPS spectroscopies, and thermogravimetric analysis. Adsorption properties of synthesized materials for removal of nicosulfuron pesticide from aqueous solutions were studied, using HPLC technique. The obtained adsorption isotherms were analyzed using Freundlich and Langmuir-Freundlich equations. Protonated PANI/BEA composites showed excellent adsorption capacity (18.4–25.4 mg g−1), that was higher than the adsorption capacity of pristine BEA zeolite (18.2 mg g−1) but slightly less than neat PANI. Among PANIs, the highest adsorption capacity of 29.8 mg g−1 of adsorbent was found for protonated PANI prepared in sulfuric acid solution. Analysis of adsorption isotherms revealed high degree of surface homogeneity for all prepared composite materials and PANIs. Proposed mechanism for enhanced adsorption of nicosulfuron on protonated composites is based on hydrogen bonding of nicosulfuron O- and N-containing groups with bridging hydroxyls of BEA zeolite and –NH/ = NH+/−NH•+ groups in protonated emeraldine salt form of PANI chains (PANI-ES), accompanied with electrostatic attractive interaction between anionic nicosulfuron species and positive = NH+/−NH•+ groups in bipolaron/polaron containing structures of PANI-ES. Presence of protons in bridging hydroxyls in BEA zeolite and in protonated PANI-ES chains is essential for excellent adsorption of nicosulfuron via hydrogen bonding on all protonated composite samples. In support of this interpretation, deprotonated PANI/BEA composites and deprotonated PANIs showed significantly lower adsorption capacities (in the range 5.5–13.0 mg g−1) compared to those of their protonated counterparts. © 2019 Elsevier Inc. |
Prekodravac, J; Vasiljević, B; Marković, Z; Jovanović, D; Kleut, D; Špitalský, Z; Mičušik, M; Danko, M; Bajuk-Bogdanović, D; Todorović-Marković, B Green and facile microwave assisted synthesis of (metal-free) N-doped carbon quantum dots for catalytic applications Journal Article Ceramics International, 45 (14), pp. 17006-17013, 2019. @article{Prekodravac201917006, title = {Green and facile microwave assisted synthesis of (metal-free) N-doped carbon quantum dots for catalytic applications}, author = {J Prekodravac and B Vasiljević and Z Marković and D Jovanović and D Kleut and Z Špitalský and M Mičušik and M Danko and D Bajuk-Bogdanović and B Todorović-Marković}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066094337&doi=10.1016%2fj.ceramint.2019.05.250&partnerID=40&md5=fa0122ceb21bc65ba25e4ff454f71ec0}, doi = {10.1016/j.ceramint.2019.05.250}, year = {2019}, date = {2019-01-01}, journal = {Ceramics International}, volume = {45}, number = {14}, pages = {17006-17013}, abstract = {Industrialization today leads to a significant increase in the environmental pollution, with number of phenols, pesticides, paints, solvents and other organic pollutants with potentially carcinogenic effect in natural resources. Investigation of some new semiconductor materials and their photocatalytic properties for removal of pollutants is a challenging work. However, limited usage of photoactive materials still requires the testing of new materials with photoactive properties. The current work introduces the swift and easy approach for synthesis of (metal–free) N–doped carbon quantum dots in water using microwave reactor. Synthesis was performed from glucose water solution by heating in microwave reactor for only 1 min, at low temperature and applied microwave power. The synthesized N–doped carbon quantum dots show remarkable photocatalytic activity for removal of toxic organic dye (Rose Bengal) under visible light irradiation. Almost 93% of the dye degradation is achieved after only 30 min of radiation. The uninspected result, that the pH of the medium has a significant effect on the performance of the synthesized material in the presence of organic dye, indicates that dots show dual behavior. In the neutral and basic conditions, they have the ability to degrade organic dye, whereas, by shifting the medium pH into acidic medium, they form a stable conjugate with Rose Bengal. © 2019 Elsevier Ltd and Techna Group S.r.l.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Industrialization today leads to a significant increase in the environmental pollution, with number of phenols, pesticides, paints, solvents and other organic pollutants with potentially carcinogenic effect in natural resources. Investigation of some new semiconductor materials and their photocatalytic properties for removal of pollutants is a challenging work. However, limited usage of photoactive materials still requires the testing of new materials with photoactive properties. The current work introduces the swift and easy approach for synthesis of (metal–free) N–doped carbon quantum dots in water using microwave reactor. Synthesis was performed from glucose water solution by heating in microwave reactor for only 1 min, at low temperature and applied microwave power. The synthesized N–doped carbon quantum dots show remarkable photocatalytic activity for removal of toxic organic dye (Rose Bengal) under visible light irradiation. Almost 93% of the dye degradation is achieved after only 30 min of radiation. The uninspected result, that the pH of the medium has a significant effect on the performance of the synthesized material in the presence of organic dye, indicates that dots show dual behavior. In the neutral and basic conditions, they have the ability to degrade organic dye, whereas, by shifting the medium pH into acidic medium, they form a stable conjugate with Rose Bengal. © 2019 Elsevier Ltd and Techna Group S.r.l. |
Pagnacco, M C; Maksimović, J P; Mudrinić, T M; Mojović, Z D; Nedić, Z P Briggs-Rauscher reaction as a novel electrochemical detector for phosphate tungsten and phosphate molybdenum bronzes Journal Article Journal of Electroanalytical Chemistry, 849 , 2019. @article{Pagnacco2019, title = {Briggs-Rauscher reaction as a novel electrochemical detector for phosphate tungsten and phosphate molybdenum bronzes}, author = {M C Pagnacco and J P Maksimović and T M Mudrinić and Z D Mojović and Z P Nedić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070642486&doi=10.1016%2fj.jelechem.2019.113369&partnerID=40&md5=91bd1072cc5862a04903df9b0a79ba16}, doi = {10.1016/j.jelechem.2019.113369}, year = {2019}, date = {2019-01-01}, journal = {Journal of Electroanalytical Chemistry}, volume = {849}, abstract = {Briggs-Rauscher (BR) oscillatory reaction is a chemical system very sensitive to different analyte addition. Changes in oscillatory dynamics, by analyte addition, could be successfully used for the determination of analyte concentration, as well as for its antioxidative/antiradical activity assessment. In this work, the BR reaction is used as a system detector for distinguishing solid unsolvable materials, such as phosphate tungsten bronze (PWB) and phosphate molybdenum bronze (PMoB), obtained by thermal treatment. The addition of different masses of PWB in BR reaction decreases its oscillation time, while the addition of different masses of PMoB had no effects on the BR oscillation time. Additionally, the BR oscillation time is the linear function of added PWB mass. The mechanism of bronzes action is investigated by using pH and electric conductivity measurements, as well as inductively coupled plasma and the cyclic voltammetry measurements, and it can be ascribed to PWB better catalytic activity then PMoB, under BR reaction condition. This work extends the practical aspect of the BR reaction for testing solid (insoluble) materials, and opening the possibility of using oscillatory reactions in material science and catalysis, in general. © 2019}, keywords = {}, pubstate = {published}, tppubtype = {article} } Briggs-Rauscher (BR) oscillatory reaction is a chemical system very sensitive to different analyte addition. Changes in oscillatory dynamics, by analyte addition, could be successfully used for the determination of analyte concentration, as well as for its antioxidative/antiradical activity assessment. In this work, the BR reaction is used as a system detector for distinguishing solid unsolvable materials, such as phosphate tungsten bronze (PWB) and phosphate molybdenum bronze (PMoB), obtained by thermal treatment. The addition of different masses of PWB in BR reaction decreases its oscillation time, while the addition of different masses of PMoB had no effects on the BR oscillation time. Additionally, the BR oscillation time is the linear function of added PWB mass. The mechanism of bronzes action is investigated by using pH and electric conductivity measurements, as well as inductively coupled plasma and the cyclic voltammetry measurements, and it can be ascribed to PWB better catalytic activity then PMoB, under BR reaction condition. This work extends the practical aspect of the BR reaction for testing solid (insoluble) materials, and opening the possibility of using oscillatory reactions in material science and catalysis, in general. © 2019 |
Mitrović, T; Lazović, S; Nastasijević, B; Pašti, I A; Vasić, V; Lazarević-Pašti, T Non-thermal plasma needle as an effective tool in dimethoate removal from water Journal Article Journal of Environmental Management, 246 , pp. 63-70, 2019. @article{Mitrović201963, title = {Non-thermal plasma needle as an effective tool in dimethoate removal from water}, author = {T Mitrović and S Lazović and B Nastasijević and I A Pašti and V Vasić and T Lazarević-Pašti}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067016418&doi=10.1016%2fj.jenvman.2019.05.143&partnerID=40&md5=1507cfb22829e1771df2c816d9009786}, doi = {10.1016/j.jenvman.2019.05.143}, year = {2019}, date = {2019-01-01}, journal = {Journal of Environmental Management}, volume = {246}, pages = {63-70}, abstract = {Intensive use of pesticides requires innovative approaches for their removal from the environment. Here we report the method for degradation of dimethoate in water using non-thermal plasma needle and analyze kinetics of dimethoate removal and possible degradation pathways. The effects of dimethoate initial concentration, plasma treatment time, Argon flow rate and the presence of radical promoters on the effectiveness of proposed method are evaluated. With argon flow rate of 0.5 slm (standard litres per minute) 1 × 10−4 M dimethoate can be removed within 30 min of treatment. Using UPLC analysis it was confirmed that one of the decomposition products is dimethoate oxo-analogue omethoate, which is in fact more toxic than dimethoate. However, the overall toxicity of contaminated water was reduced upon the treatment. The addition of H2O2 as a free radical promoter enhances dimethoate removal, while K2S2O8 results with selective conversion to omethoate. Using mass spectrometry in combination with the theoretical calculations, possible degradation pathways were proposed. The feasibility of the proposed method for dimethoate degradation in real water samples is confirmed. The proposed method is demonstrated as a highly effective approach for dimethoate removal without significant accumulation of undesirable toxic products and secondary waste. © 2019 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Intensive use of pesticides requires innovative approaches for their removal from the environment. Here we report the method for degradation of dimethoate in water using non-thermal plasma needle and analyze kinetics of dimethoate removal and possible degradation pathways. The effects of dimethoate initial concentration, plasma treatment time, Argon flow rate and the presence of radical promoters on the effectiveness of proposed method are evaluated. With argon flow rate of 0.5 slm (standard litres per minute) 1 × 10−4 M dimethoate can be removed within 30 min of treatment. Using UPLC analysis it was confirmed that one of the decomposition products is dimethoate oxo-analogue omethoate, which is in fact more toxic than dimethoate. However, the overall toxicity of contaminated water was reduced upon the treatment. The addition of H2O2 as a free radical promoter enhances dimethoate removal, while K2S2O8 results with selective conversion to omethoate. Using mass spectrometry in combination with the theoretical calculations, possible degradation pathways were proposed. The feasibility of the proposed method for dimethoate degradation in real water samples is confirmed. The proposed method is demonstrated as a highly effective approach for dimethoate removal without significant accumulation of undesirable toxic products and secondary waste. © 2019 Elsevier Ltd |