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2020 |
Matijević, M; Nakarada, Đ; Liang, X; Korićanac, L; Rajsiglova, L; Vannucci, L; Nešić, M; Vranješ, M; Mojović, M; Mi, L; Estrela-Lopis, I; Böttner, J; Šaponjić, Z; Petković, M; Stepić, M Biocompatibility of TiO2 prolate nanospheroids as a potential photosenzitizer in therapy of cancer Journal Article Journal of Nanoparticle Research, 22 (7), 2020. @article{Matijević2020, title = {Biocompatibility of TiO2 prolate nanospheroids as a potential photosenzitizer in therapy of cancer}, author = {M Matijević and Đ Nakarada and X Liang and L Korićanac and L Rajsiglova and L Vannucci and M Nešić and M Vranješ and M Mojović and L Mi and I Estrela-Lopis and J Böttner and Z Šaponjić and M Petković and M Stepić}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087054250&doi=10.1007%2fs11051-020-04899-3&partnerID=40&md5=9019709ed3fedee914b332555d4534ce}, doi = {10.1007/s11051-020-04899-3}, year = {2020}, date = {2020-01-01}, journal = {Journal of Nanoparticle Research}, volume = {22}, number = {7}, abstract = {TiO2 prolatenanospheroids (PNSs) may be photosensitizers (PSs), which act by catalyzation of hydroxyl radical (∙OH) formation upon light illumination. ∙OH might, in turn, contribute to killing of cancer cells. On the other hand, there is great concern about toxicity in the dark of TiO2 nanoparticles in general. In this work, we have investigated the biocompatibility of TiO2 PNSs of the anatase crystal form (length between 100 and 300 nm and width 50 nm) in the dark with immune cells and light-induced cytotoxicity on several cancer cell lines. The effects of the treatment of different cell lines with several concentrations of TiO2 PNSs suspensions showed the specifics of cells’ viability and the intracellular localization. The results of in vitro studies obtained by cytotoxicity assays adjusted to individual cell lines’ metabolism point towards the biocompatibility of TiO2 PNSs at low and moderate concentrations in the dark, which neither kill the cells, nor induce activation of the immune system cells. Laser scanning confocal microscopy revealed that PNSs are taken up by cells, and insight into the intracellular distribution was obtained in this study. © 2020, Springer Nature B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } TiO2 prolatenanospheroids (PNSs) may be photosensitizers (PSs), which act by catalyzation of hydroxyl radical (∙OH) formation upon light illumination. ∙OH might, in turn, contribute to killing of cancer cells. On the other hand, there is great concern about toxicity in the dark of TiO2 nanoparticles in general. In this work, we have investigated the biocompatibility of TiO2 PNSs of the anatase crystal form (length between 100 and 300 nm and width 50 nm) in the dark with immune cells and light-induced cytotoxicity on several cancer cell lines. The effects of the treatment of different cell lines with several concentrations of TiO2 PNSs suspensions showed the specifics of cells’ viability and the intracellular localization. The results of in vitro studies obtained by cytotoxicity assays adjusted to individual cell lines’ metabolism point towards the biocompatibility of TiO2 PNSs at low and moderate concentrations in the dark, which neither kill the cells, nor induce activation of the immune system cells. Laser scanning confocal microscopy revealed that PNSs are taken up by cells, and insight into the intracellular distribution was obtained in this study. © 2020, Springer Nature B.V. |
Milenković, D; Avdović, E; Dimić, D; Sudha, S; Ramarajan, D; Milanović, ; Trifunović, S; Marković, Z S Journal of Molecular Structure, 1209 , 2020. @article{Milenković2020b, title = {Vibrational and Hirshfeld surface analyses, quantum chemical calculations, and molecular docking studies of coumarin derivative 3-(1-m-toluidinoethylidene)-chromane-2,4-dione and its corresponding palladium(II) complex}, author = {D Milenković and E Avdović and D Dimić and S Sudha and D Ramarajan and Milanović and S Trifunović and Z S Marković}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080037349&doi=10.1016%2fj.molstruc.2020.127935&partnerID=40&md5=b6333b566889ba33eb9c616fd994d2cc}, doi = {10.1016/j.molstruc.2020.127935}, year = {2020}, date = {2020-01-01}, journal = {Journal of Molecular Structure}, volume = {1209}, abstract = {In this study, the analysis of vibrational spectra and electronic structure of 3-(1-m-toluidinoethylidene)-chromane-2,4-dione (L1) and its corresponding palladium (II) complex (C1) was employed to characterize the spectroscopic behavior and molecular structure of the investigated compounds by applying B3LYP-D3BJ/6-311+G(d,p) level of theory. Hirshfeld surface analysis of the intermolecular interactions in crystal structure L1 was performed. The AIM and NBO analyses were used to understand the type, nature, and strength of intramolecular interactions and to examine the electronic structure of the studied molecules. The calculation of HOMO and LUMO energies was applied in order to present the charge transfer within the molecule. The computational molecular docking studies of title compounds was performed with special emphasis on differences in binding of ligand and complex. © 2020}, keywords = {}, pubstate = {published}, tppubtype = {article} } In this study, the analysis of vibrational spectra and electronic structure of 3-(1-m-toluidinoethylidene)-chromane-2,4-dione (L1) and its corresponding palladium (II) complex (C1) was employed to characterize the spectroscopic behavior and molecular structure of the investigated compounds by applying B3LYP-D3BJ/6-311+G(d,p) level of theory. Hirshfeld surface analysis of the intermolecular interactions in crystal structure L1 was performed. The AIM and NBO analyses were used to understand the type, nature, and strength of intramolecular interactions and to examine the electronic structure of the studied molecules. The calculation of HOMO and LUMO energies was applied in order to present the charge transfer within the molecule. The computational molecular docking studies of title compounds was performed with special emphasis on differences in binding of ligand and complex. © 2020 |
Ilić, Medić M; Bundaleski, N; Ivanović, N; Teodoro, O M N D; Rakočević, Z; Minić, D; Romčević, N; Radisavljević, I XPS measurements of air-exposed Cd(Zn)1–xFexTe1–ySey surfaces revisited Journal Article Vacuum, 176 , 2020. @article{MedićIlić2020, title = {XPS measurements of air-exposed Cd(Zn)1–xFexTe1–ySey surfaces revisited}, author = {M Medić Ilić and N Bundaleski and N Ivanović and O M N D Teodoro and Z Rakočević and D Minić and N Romčević and I Radisavljević}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082390920&doi=10.1016%2fj.vacuum.2020.109340&partnerID=40&md5=61cbfffe3734322d74f90fc164992f5f}, doi = {10.1016/j.vacuum.2020.109340}, year = {2020}, date = {2020-01-01}, journal = {Vacuum}, volume = {176}, abstract = {Recently introduced model for quantitative analysis of in-depth non-uniform surfaces is applied to reexamine the X-ray Photoelectron Spectroscopy (XPS) data of Cd0.99Fe0.01Te0.97Se0.03 and Zn0.98Fe0.02Te0.91Se0.09 crystalline samples. Special attention is paid to the precise identification of phases which form the bulk-like near-surface region and the surface overlayers (the oxide layer and the layer of organic impurities), as well as the influence of surface morphology on the measurements. The obtained results fully support earlier qualitative estimations, but also provide new quantitative insight into the composition of the three investigated regions. The near-surface region of Cd0.99Fe0.01Te0.97Se0.03 and Zn0.98Fe0.02Te0.91Se0.09 samples is slightly electropositive, with cation/anion ratio 52:48 and 53:47, respectively. Model surface structures, which are fully compatible with the experimental results, comprise 0.76 nm thick CdTeO3 layer at the surface of Cd0.99Fe0.01Te0.97Se0.03 and 0.33 nm thick mixed ZnO/TeO2 oxide layer on Zn0.98Fe0.02Te0.91Se0.09. In both samples the oxide layer is only a few atomic layers thick, implying that it suppresses further rapid migration of oxygen into the bulk. © 2020 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recently introduced model for quantitative analysis of in-depth non-uniform surfaces is applied to reexamine the X-ray Photoelectron Spectroscopy (XPS) data of Cd0.99Fe0.01Te0.97Se0.03 and Zn0.98Fe0.02Te0.91Se0.09 crystalline samples. Special attention is paid to the precise identification of phases which form the bulk-like near-surface region and the surface overlayers (the oxide layer and the layer of organic impurities), as well as the influence of surface morphology on the measurements. The obtained results fully support earlier qualitative estimations, but also provide new quantitative insight into the composition of the three investigated regions. The near-surface region of Cd0.99Fe0.01Te0.97Se0.03 and Zn0.98Fe0.02Te0.91Se0.09 samples is slightly electropositive, with cation/anion ratio 52:48 and 53:47, respectively. Model surface structures, which are fully compatible with the experimental results, comprise 0.76 nm thick CdTeO3 layer at the surface of Cd0.99Fe0.01Te0.97Se0.03 and 0.33 nm thick mixed ZnO/TeO2 oxide layer on Zn0.98Fe0.02Te0.91Se0.09. In both samples the oxide layer is only a few atomic layers thick, implying that it suppresses further rapid migration of oxygen into the bulk. © 2020 Elsevier Ltd |
Ranđelović, D; Jakovljević, K; Mišljenović, T; Savović, J; Kuzmanović, M; Mihailović, N; Jovanović, S Accumulation of Potentially Toxic Elements in Invasive Ambrosia artemisiifolia on Sites with Different Levels of Anthropogenic Pollution Journal Article Water, Air, and Soil Pollution, 231 (6), 2020. @article{Ranđelović2020, title = {Accumulation of Potentially Toxic Elements in Invasive Ambrosia artemisiifolia on Sites with Different Levels of Anthropogenic Pollution}, author = {D Ranđelović and K Jakovljević and T Mišljenović and J Savović and M Kuzmanović and N Mihailović and S Jovanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085531031&doi=10.1007%2fs11270-020-04655-2&partnerID=40&md5=0ed44990944f02acefd1ae79b2220ffa}, doi = {10.1007/s11270-020-04655-2}, year = {2020}, date = {2020-01-01}, journal = {Water, Air, and Soil Pollution}, volume = {231}, number = {6}, abstract = {This study investigated invasive Ambrosia artemisiifolia from five localities with different levels of anthropogenic pollution in order to determine the potential for accumulation of trace metals and metaloids. Physical characteristics of the soil are presented, together with concentrations of As, B, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Sr, and Zn in both plant and soil. The tested samples displayed considerable differences in element concentrations, depending on the level of anthropogenic activities, with the highest concentrations of elements observed in samples from Stolice and Piskanja, the sites with most intensive human influence. A trend of shoot accumulation can be observed in A. artemisiifolia, but without hyperaccumulation, along with lower root concentrations in almost all analyzed samples. This may pose an additional environmental risk, as accumulated elements can spread to other components of the ecosystem. While A. artemisiifolia acumulates a high and even toxic rate of B in shoots regardless of boron concentration in soil, there is a high correlation of Ba, Pb, and Zn concentrations in species shoots with their respective concentration in the soil. Successful colonization of both natural and anthropogenically polluted habitats indicates high tolerance of A. artemisiifolia, which complements its wide environmental amplitude. © 2020, Springer Nature Switzerland AG.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This study investigated invasive Ambrosia artemisiifolia from five localities with different levels of anthropogenic pollution in order to determine the potential for accumulation of trace metals and metaloids. Physical characteristics of the soil are presented, together with concentrations of As, B, Ba, Ca, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Sr, and Zn in both plant and soil. The tested samples displayed considerable differences in element concentrations, depending on the level of anthropogenic activities, with the highest concentrations of elements observed in samples from Stolice and Piskanja, the sites with most intensive human influence. A trend of shoot accumulation can be observed in A. artemisiifolia, but without hyperaccumulation, along with lower root concentrations in almost all analyzed samples. This may pose an additional environmental risk, as accumulated elements can spread to other components of the ecosystem. While A. artemisiifolia acumulates a high and even toxic rate of B in shoots regardless of boron concentration in soil, there is a high correlation of Ba, Pb, and Zn concentrations in species shoots with their respective concentration in the soil. Successful colonization of both natural and anthropogenically polluted habitats indicates high tolerance of A. artemisiifolia, which complements its wide environmental amplitude. © 2020, Springer Nature Switzerland AG. |
Dobrota, A S; Pašti, I A; Mentus, S V; Johansson, B; Skorodumova, N V Altering the reactivity of pristine, N- and P-doped graphene by strain engineering: A DFT view on energy related aspects Journal Article Applied Surface Science, 514 , 2020. @article{Dobrota2020, title = {Altering the reactivity of pristine, N- and P-doped graphene by strain engineering: A DFT view on energy related aspects}, author = {A S Dobrota and I A Pašti and S V Mentus and B Johansson and N V Skorodumova}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081026675&doi=10.1016%2fj.apsusc.2020.145937&partnerID=40&md5=144a6d323679a1f70b41dac3fc54ad91}, doi = {10.1016/j.apsusc.2020.145937}, year = {2020}, date = {2020-01-01}, journal = {Applied Surface Science}, volume = {514}, abstract = {For carbon-based materials, in contrast to metal surfaces, a general relationship between strain and reactivity is not yet established, even though there are literature reports on strained graphene. Knowledge of such relationships would be extremely beneficial for understanding the reactivity of graphene-based surfaces and finding optimisation strategies which would make these materials more suitable for targeted applications. Here we investigate the effects of compressive and tensile strain (up to ±5%) on the structure, electronic properties and reactivity of pure, N-doped and P-doped graphene, using DFT calculations. We demonstrate the possibility of tuning the topology of the graphene surface by strain, as well as by the choice of the dopant atom. The reactivity of (doped) strained graphene is probed using H and Na as simple adsorbates of great practical importance. Strain can both enhance and weaken H and Na adsorption on (doped) graphene. In case of Na adsorption, a linear relationship is observed between the Na adsorption energy on P-doped graphene and the phosphorus charge. A linear relationship between the Na adsorption energy on flat graphene surfaces and strain is found. Based on the adsorption energies and electrical conductivity, potentially good candidates for hydrogen storage and sodium-ion battery electrodes are discussed. © 2020}, keywords = {}, pubstate = {published}, tppubtype = {article} } For carbon-based materials, in contrast to metal surfaces, a general relationship between strain and reactivity is not yet established, even though there are literature reports on strained graphene. Knowledge of such relationships would be extremely beneficial for understanding the reactivity of graphene-based surfaces and finding optimisation strategies which would make these materials more suitable for targeted applications. Here we investigate the effects of compressive and tensile strain (up to ±5%) on the structure, electronic properties and reactivity of pure, N-doped and P-doped graphene, using DFT calculations. We demonstrate the possibility of tuning the topology of the graphene surface by strain, as well as by the choice of the dopant atom. The reactivity of (doped) strained graphene is probed using H and Na as simple adsorbates of great practical importance. Strain can both enhance and weaken H and Na adsorption on (doped) graphene. In case of Na adsorption, a linear relationship is observed between the Na adsorption energy on P-doped graphene and the phosphorus charge. A linear relationship between the Na adsorption energy on flat graphene surfaces and strain is found. Based on the adsorption energies and electrical conductivity, potentially good candidates for hydrogen storage and sodium-ion battery electrodes are discussed. © 2020 |
Puthenkalathil, R C; Etinski, M; Ensing, B Unraveling the mechanism of biomimetic hydrogen fuel production-a first principles molecular dynamics study Journal Article Physical Chemistry Chemical Physics, 22 (19), pp. 10447-10454, 2020. @article{Puthenkalathil202010447, title = {Unraveling the mechanism of biomimetic hydrogen fuel production-a first principles molecular dynamics study}, author = {R C Puthenkalathil and M Etinski and B Ensing}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085263958&doi=10.1039%2fc9cp06770a&partnerID=40&md5=6d9fc138d6bf7706880f82f477c4455b}, doi = {10.1039/c9cp06770a}, year = {2020}, date = {2020-01-01}, journal = {Physical Chemistry Chemical Physics}, volume = {22}, number = {19}, pages = {10447-10454}, abstract = {The Fe2(bdt)(CO)6 [bdt = benzenedithiolato] complex, a synthetic mimic of the [FeFe] hydrogenase enzyme can electrochemically convert protons into molecular hydrogen. Molecular understanding of the cascade of reaction steps is important for the design of more efficient catalysts. In this study, we investigate the reaction mechanism of the hydrogen production catalysis in explicit solution of acetonitrile using first principles molecular dynamics simulations. We have characterized all reduction and protonation intermediates taking part in the catalytic cycle. Free energy surfaces of the activated reaction steps are calculated using metadynamics. We find that the second protonation leading to molecular hydrogen formation is the rate limiting step. Direct protonation of the bridging hydride by a proton from the solution to form H2 is the most favorable reaction pathway. However, also a bdt sulfur atom can become protonated, leading to a possible proton trap state that reduces the catalytic efficiency. Our calculations validate the ECEC mechanism proposed using cyclic voltammetry. © 2020 the Owner Societies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Fe2(bdt)(CO)6 [bdt = benzenedithiolato] complex, a synthetic mimic of the [FeFe] hydrogenase enzyme can electrochemically convert protons into molecular hydrogen. Molecular understanding of the cascade of reaction steps is important for the design of more efficient catalysts. In this study, we investigate the reaction mechanism of the hydrogen production catalysis in explicit solution of acetonitrile using first principles molecular dynamics simulations. We have characterized all reduction and protonation intermediates taking part in the catalytic cycle. Free energy surfaces of the activated reaction steps are calculated using metadynamics. We find that the second protonation leading to molecular hydrogen formation is the rate limiting step. Direct protonation of the bridging hydride by a proton from the solution to form H2 is the most favorable reaction pathway. However, also a bdt sulfur atom can become protonated, leading to a possible proton trap state that reduces the catalytic efficiency. Our calculations validate the ECEC mechanism proposed using cyclic voltammetry. © 2020 the Owner Societies. |
Brkovic, S M; Kaninski, Marceta M P; Lausevic, P Z; Saponjic, A B; Radulovic, A M; Rakic, A A; Pasti, I A; Nikolic, V М International Journal of Hydrogen Energy, 45 (27), pp. 13929-13938, 2020. @article{Brkovic202013929, title = {Non-stoichiometric tungsten-carbide-oxide-supported Pt–Ru anode catalysts for PEM fuel cells – From basic electrochemistry to fuel cell performance}, author = {S M Brkovic and M P Marceta Kaninski and P Z Lausevic and A B Saponjic and A M Radulovic and A A Rakic and I A Pasti and V М Nikolic}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082747239&doi=10.1016%2fj.ijhydene.2020.03.086&partnerID=40&md5=6f42c2081cf1e926f3d3d807bf9b0fb1}, doi = {10.1016/j.ijhydene.2020.03.086}, year = {2020}, date = {2020-01-01}, journal = {International Journal of Hydrogen Energy}, volume = {45}, number = {27}, pages = {13929-13938}, abstract = {Durability and cost of Proton Exchange Membrane fuel cells (PEMFCs) are two major factors delaying their commercialization. Cost is associated with the price of the catalysts, while durability is associated with degradation and poisoning of the catalysts, primarily by CO. This motivated us to develop tungsten-carbide-oxide (WxCyOz) as a new non-carbon based catalyst support for Pt–Ru–based anode PEMFC catalyst. The aim was to improve performance and obtain higher CO tolerance compared to commercial catalysts. The performance of obtained PtRu/WxCyOz catalysts was investigated using cyclic voltammetry, linear scan voltammetry and rotating disk electrode voltammetry. Particular attention was given to the analysis of CO poisoning, to better understand how WxCyOz species can contribute to the CO tolerance of PtRu/WxCyOz. Improved oxidation of COads at low potentials (E < 0.5 V vs. RHE) was ascribed to OH provided by the oxide phase at the interfacial region between the support and the PtRu particles. On the other hand, at high potentials (E > 0.5 V vs. RHE) CO removal proceeds dominantly via OH provided from the oxidized metal sites. The obtained catalyst with the best performance (30% PtRu/WxCyOz) was tested as an anode catalyst in PEM fuel cell. When using synthetic reformate as a fuel in PEMFC, there is a significant power drop of 35.3 % for the commercial 30% PtRu/C catalyst, while for the PtRu/WxCyOz anode catalyst this drop is around 16 %. © 2020 Hydrogen Energy Publications LLC}, keywords = {}, pubstate = {published}, tppubtype = {article} } Durability and cost of Proton Exchange Membrane fuel cells (PEMFCs) are two major factors delaying their commercialization. Cost is associated with the price of the catalysts, while durability is associated with degradation and poisoning of the catalysts, primarily by CO. This motivated us to develop tungsten-carbide-oxide (WxCyOz) as a new non-carbon based catalyst support for Pt–Ru–based anode PEMFC catalyst. The aim was to improve performance and obtain higher CO tolerance compared to commercial catalysts. The performance of obtained PtRu/WxCyOz catalysts was investigated using cyclic voltammetry, linear scan voltammetry and rotating disk electrode voltammetry. Particular attention was given to the analysis of CO poisoning, to better understand how WxCyOz species can contribute to the CO tolerance of PtRu/WxCyOz. Improved oxidation of COads at low potentials (E < 0.5 V vs. RHE) was ascribed to OH provided by the oxide phase at the interfacial region between the support and the PtRu particles. On the other hand, at high potentials (E > 0.5 V vs. RHE) CO removal proceeds dominantly via OH provided from the oxidized metal sites. The obtained catalyst with the best performance (30% PtRu/WxCyOz) was tested as an anode catalyst in PEM fuel cell. When using synthetic reformate as a fuel in PEMFC, there is a significant power drop of 35.3 % for the commercial 30% PtRu/C catalyst, while for the PtRu/WxCyOz anode catalyst this drop is around 16 %. © 2020 Hydrogen Energy Publications LLC |
Maksimovic, J P; Tošovic, J; Pagnacco, M C Insight into the origin of pyrocatechol inhibition on oscillating bray-liebhafsky reaction: Combined experimental and theoretical study Journal Article Bulletin of the Chemical Society of Japan, 93 (5), pp. 676-684, 2020. @article{Maksimovic2020676, title = {Insight into the origin of pyrocatechol inhibition on oscillating bray-liebhafsky reaction: Combined experimental and theoretical study}, author = {J P Maksimovic and J Tošovic and M C Pagnacco}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086148155&doi=10.1246%2fbcsj.20190296&partnerID=40&md5=0b720ef8b7ed7a7f6ce0a86d72c3a80f}, doi = {10.1246/bcsj.20190296}, year = {2020}, date = {2020-01-01}, journal = {Bulletin of the Chemical Society of Japan}, volume = {93}, number = {5}, pages = {676-684}, abstract = {The pyrocatechol inhibitory effect on the oscillatory Bray- Liebhafsky (BL) reaction is reported. Obtained results are compared with those available in the literature (R. Cervellati et al, Helvetica Chimica Acta 2001) for Briggs-Rauscher (BR) reaction with pyrocatechol addition. The two orders of magnitude larger calibration curve slope obtained in BR in comparison to BL reaction, suggests that different reactions are responsible for inhibitory effects in these systems. The potential explanation of pyrocatechol behavior is given by employing the ultravioletvisible (UV/VIS) spectroscopy, density functional theory, and coupled cluster computational methods. The last two were employed for the first time to discover potential candidates among unstable chemical species HIO, HIO2, I2O, HOO·, HO·, IO·, IO2·, and I· of the BL (and BR) system for reaction with pyrocatechol. The calculated reaction rate constants for the hydrogen atom transfer reactions between pyrocatechol and free radical intermediates indicate the following order of reactivity: HO· > IO· > HOO· > IO2·. The same order of reactivity is also observed in the case of a thermodynamic investigation. In addition, kinetic insight indicates that the inhibitory behavior of pyrocatechol could not be explained with one particular chemical reaction in the BL (or in the BR) oscillatory system. © 2020 The Chemical Society of Japan.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The pyrocatechol inhibitory effect on the oscillatory Bray- Liebhafsky (BL) reaction is reported. Obtained results are compared with those available in the literature (R. Cervellati et al, Helvetica Chimica Acta 2001) for Briggs-Rauscher (BR) reaction with pyrocatechol addition. The two orders of magnitude larger calibration curve slope obtained in BR in comparison to BL reaction, suggests that different reactions are responsible for inhibitory effects in these systems. The potential explanation of pyrocatechol behavior is given by employing the ultravioletvisible (UV/VIS) spectroscopy, density functional theory, and coupled cluster computational methods. The last two were employed for the first time to discover potential candidates among unstable chemical species HIO, HIO2, I2O, HOO·, HO·, IO·, IO2·, and I· of the BL (and BR) system for reaction with pyrocatechol. The calculated reaction rate constants for the hydrogen atom transfer reactions between pyrocatechol and free radical intermediates indicate the following order of reactivity: HO· > IO· > HOO· > IO2·. The same order of reactivity is also observed in the case of a thermodynamic investigation. In addition, kinetic insight indicates that the inhibitory behavior of pyrocatechol could not be explained with one particular chemical reaction in the BL (or in the BR) oscillatory system. © 2020 The Chemical Society of Japan. |
Belic, D S; Ristic, M M; Cherkani-Hassani, H; Urbain, X; Defrance, P Electron-impact dissociation of N2D+ cations to D+ fragments Journal Article European Physical Journal D, 74 (5), 2020. @article{Belic2020, title = {Electron-impact dissociation of N2D+ cations to D+ fragments}, author = {D S Belic and M M Ristic and H Cherkani-Hassani and X Urbain and P Defrance}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085186493&doi=10.1140%2fepjd%2fe2020-100623-1&partnerID=40&md5=5a231866db84de57047fef3b2fc07ab5}, doi = {10.1140/epjd/e2020-100623-1}, year = {2020}, date = {2020-01-01}, journal = {European Physical Journal D}, volume = {74}, number = {5}, abstract = {Abstract: Absolute cross sections for electron-impact dissociation of N2D+ cations to the light D+ fragments are reported for the first time. The animated electron-ion crossed-beam method is applied in the energy range from thresholds up to 2 keV. The heavy N2 + fragments are also detected and their kinetic energy distribution is analyzed at a selected electron energy. The measured cross-sections are corrected for incomplete collection of the light D+ fragments by performing careful analyser magnetic field scan together with a Monte-Carlo procedure. Inclusive absolute cross sections are determined. Dissociative excitation (DE) and dissociative ionization (DI) contributions are separated and the corresponding partial cross sections for D+ fragment production are determined at selected electron energies. The inclusive cross section for D+ fragment production has a maximum of (87 ± 7)×10−18 cm2, at 95.1 eV, with the dominant contribution from the DI process. Graphical abstract: [Figure not available: see fulltext.] © 2020, EDP Sciences / Società Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract: Absolute cross sections for electron-impact dissociation of N2D+ cations to the light D+ fragments are reported for the first time. The animated electron-ion crossed-beam method is applied in the energy range from thresholds up to 2 keV. The heavy N2 + fragments are also detected and their kinetic energy distribution is analyzed at a selected electron energy. The measured cross-sections are corrected for incomplete collection of the light D+ fragments by performing careful analyser magnetic field scan together with a Monte-Carlo procedure. Inclusive absolute cross sections are determined. Dissociative excitation (DE) and dissociative ionization (DI) contributions are separated and the corresponding partial cross sections for D+ fragment production are determined at selected electron energies. The inclusive cross section for D+ fragment production has a maximum of (87 ± 7)×10−18 cm2, at 95.1 eV, with the dominant contribution from the DI process. Graphical abstract: [Figure not available: see fulltext.] © 2020, EDP Sciences / Società Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature. |
Vujacic-Mirski, K; Bruns, K; Kalinovic, S; Oelze, M; Kröller-Schön, S; Steven, S; Mojovic, M; Korac, B; Münzel, T; Daiber, A Antioxidants, 9 (5), 2020. @article{Vujacic-Mirski2020, title = {Development of an analytical assay for electrochemical detection and quantification of protein-bound 3-nitrotyrosine in biological samples and comparison with classical, antibody-based methods}, author = {K Vujacic-Mirski and K Bruns and S Kalinovic and M Oelze and S Kröller-Schön and S Steven and M Mojovic and B Korac and T Münzel and A Daiber}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084254228&doi=10.3390%2fantiox9050388&partnerID=40&md5=9144982ce1a9eea136a9663ecf80df32}, doi = {10.3390/antiox9050388}, year = {2020}, date = {2020-01-01}, journal = {Antioxidants}, volume = {9}, number = {5}, abstract = {Reactive oxygen and nitrogen species (RONS) cause oxidative damage, which is associated with endothelial dysfunction and cardiovascular disease, but may also contribute to redox signaling. Therefore, their precise detection is important for the evaluation of disease mechanisms. Here, we compared three different methods for the detection of 3-nitrotyrosine (3-NT), a marker of nitro-oxidative stress, in biological samples. Nitrated proteins were generated by incubation with peroxynitrite or 3-morpholino sydnonimine (Sin-1) and subjected to total hydrolysis using pronase, a mixture of different proteases. The 3-NT was then separated by high performance liquid chromatography (HPLC) and quantified by electrochemical detection (ECD, CoulArray) and compared to classical methods, namely enzyme-linked immunosorbent assay (ELISA) and dot blot analysis using specific 3-NT antibodies. Calibration curves for authentic 3-NT (detection limit 10 nM) and a concentration-response pattern for 3-NT obtained from digested nitrated bovine serum albumin (BSA) were highly linear over a wide 3-NT concentration range. Also, ex vivo nitration of protein from heart, isolated mitochondria, and serum/plasma could be quantified using the HPLC/ECD method and was confirmed by LC-MS/MS. Of note, nitro-oxidative damage of mitochondria results in increased superoxide (O2 •–) formation rates (measured by dihydroethidium-based HPLC assay), pointing to a self-amplification mechanism of oxidative stress. Based on our ex vivo data, the CoulArray quantification method for 3-NT seems to have some advantages regarding sensitivity and selectivity. Establishing a reliable automated HPLC assay for the routine quantification of 3-NT in biological samples of cell culture, of animal and human origin seems to be more sophisticated than expected. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Reactive oxygen and nitrogen species (RONS) cause oxidative damage, which is associated with endothelial dysfunction and cardiovascular disease, but may also contribute to redox signaling. Therefore, their precise detection is important for the evaluation of disease mechanisms. Here, we compared three different methods for the detection of 3-nitrotyrosine (3-NT), a marker of nitro-oxidative stress, in biological samples. Nitrated proteins were generated by incubation with peroxynitrite or 3-morpholino sydnonimine (Sin-1) and subjected to total hydrolysis using pronase, a mixture of different proteases. The 3-NT was then separated by high performance liquid chromatography (HPLC) and quantified by electrochemical detection (ECD, CoulArray) and compared to classical methods, namely enzyme-linked immunosorbent assay (ELISA) and dot blot analysis using specific 3-NT antibodies. Calibration curves for authentic 3-NT (detection limit 10 nM) and a concentration-response pattern for 3-NT obtained from digested nitrated bovine serum albumin (BSA) were highly linear over a wide 3-NT concentration range. Also, ex vivo nitration of protein from heart, isolated mitochondria, and serum/plasma could be quantified using the HPLC/ECD method and was confirmed by LC-MS/MS. Of note, nitro-oxidative damage of mitochondria results in increased superoxide (O2 •–) formation rates (measured by dihydroethidium-based HPLC assay), pointing to a self-amplification mechanism of oxidative stress. Based on our ex vivo data, the CoulArray quantification method for 3-NT seems to have some advantages regarding sensitivity and selectivity. Establishing a reliable automated HPLC assay for the routine quantification of 3-NT in biological samples of cell culture, of animal and human origin seems to be more sophisticated than expected. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. |
Milovanović, B; Stanojević, A; Etinski, M; Petković, M Intriguing Intermolecular Interplay in Guanine Quartet Complexes with Alkali and Alkaline Earth Cations Journal Article Journal of Physical Chemistry B, 124 (15), pp. 3002-3014, 2020. @article{Milovanović20203002, title = {Intriguing Intermolecular Interplay in Guanine Quartet Complexes with Alkali and Alkaline Earth Cations}, author = {B Milovanović and A Stanojević and M Etinski and M Petković}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083545675&doi=10.1021%2facs.jpcb.0c01165&partnerID=40&md5=586aadb3b4c40663d93672180ff09f1b}, doi = {10.1021/acs.jpcb.0c01165}, year = {2020}, date = {2020-01-01}, journal = {Journal of Physical Chemistry B}, volume = {124}, number = {15}, pages = {3002-3014}, abstract = {The possibility to target noncanonical guanine structures with specific ligands for therapeutic purposes inspired numerous theoretical and experimental investigations of a guanine quartet and its stacked composites. In this work, we employed the interacting quantum atoms methodology to study interactions among different fragments in complexes composed of a guanine quartet and alkali (Li+, Na+, K+) or alkaline earth (Be2+, Mg2+, Ca2+) cations in vacuo: metal-quartet interaction, influence of the cation on guanine-guanine interaction, as well as hydrogen bond cooperativity in the guanine quartet and its complexes with metal ions. Interestingly, although the presence of a cation intensifies interaction among guanine molecules, it lowers their binding energy because of notable quartet's distortion which is responsible for guanines' substantial deformation energy. This phenomenon is particularly pronounced with Be2+ which, out of the six analyzed cations, enhances hydrogen bond cooperativity to the greatest extent. © 2020 American Chemical Society.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The possibility to target noncanonical guanine structures with specific ligands for therapeutic purposes inspired numerous theoretical and experimental investigations of a guanine quartet and its stacked composites. In this work, we employed the interacting quantum atoms methodology to study interactions among different fragments in complexes composed of a guanine quartet and alkali (Li+, Na+, K+) or alkaline earth (Be2+, Mg2+, Ca2+) cations in vacuo: metal-quartet interaction, influence of the cation on guanine-guanine interaction, as well as hydrogen bond cooperativity in the guanine quartet and its complexes with metal ions. Interestingly, although the presence of a cation intensifies interaction among guanine molecules, it lowers their binding energy because of notable quartet's distortion which is responsible for guanines' substantial deformation energy. This phenomenon is particularly pronounced with Be2+ which, out of the six analyzed cations, enhances hydrogen bond cooperativity to the greatest extent. © 2020 American Chemical Society. |
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. |
Carević, M V; Savić, T D; Abazović, N D; Mojović, M D; Novaković, T B; Čomor, M I Effect of Fe3+ ion doping on photocatalytic ability of nanozirconia ceramic to degrade 2, 4, 6- trichlorophenol Journal Article Ceramics International, 46 (5), pp. 6820-6827, 2020. @article{Carević20206820, title = {Effect of Fe3+ ion doping on photocatalytic ability of nanozirconia ceramic to degrade 2, 4, 6- trichlorophenol}, author = {M V Carević and T D Savić and N D Abazović and M D Mojović and T B Novaković and M I Čomor}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078751596&doi=10.1016%2fj.ceramint.2019.11.175&partnerID=40&md5=1d7e4c1e95c26cae0304d07dcdf02f98}, doi = {10.1016/j.ceramint.2019.11.175}, year = {2020}, date = {2020-01-01}, journal = {Ceramics International}, volume = {46}, number = {5}, pages = {6820-6827}, abstract = {Pure and a series of Fe3+ doped zirconia nanopowders were synthesized combining colloidal chemistry and solvothermal method from organometallic precursors in order to correlate doping and properties of zirconia matrix. After annealing of washed nanopowders at 600 °C, detailed characterization was performed using X-ray diffraction, UV/Vis absorption and luminescence, infrared and electron paramagnetic spectroscopy, transmission electron microscopy and BET measurements. Zirconia samples had mixed monoclinic and tetragonal crystalline phase; increasing Fe3+ ions concentration was followed by increasing of tetragonal phase share. In the sample with highest Fe3+ concentration, hematite can be detected. Also, UV/Vis spectrophotometry showed that Fe3+ doping lowers effective band gap of zirconia matrix from 4.5 eV (bulk value) to 2.1 eV for doped/nanocomposite samples. EPR measurements proved presence of dopant and showed that isolated Fe3+ ions in zirconia matrix exist in both crystalline phases; monoclinic and tetragonal (g ~ 4.8 and g ~ 4.27–4.2, respectively) surroundings. Zirconia samples were also successfully used as photocatalysts for photocatalytic degradation of 2, 4, 6, trichlorophenol. © 2019 Elsevier Ltd and Techna Group S.r.l.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Pure and a series of Fe3+ doped zirconia nanopowders were synthesized combining colloidal chemistry and solvothermal method from organometallic precursors in order to correlate doping and properties of zirconia matrix. After annealing of washed nanopowders at 600 °C, detailed characterization was performed using X-ray diffraction, UV/Vis absorption and luminescence, infrared and electron paramagnetic spectroscopy, transmission electron microscopy and BET measurements. Zirconia samples had mixed monoclinic and tetragonal crystalline phase; increasing Fe3+ ions concentration was followed by increasing of tetragonal phase share. In the sample with highest Fe3+ concentration, hematite can be detected. Also, UV/Vis spectrophotometry showed that Fe3+ doping lowers effective band gap of zirconia matrix from 4.5 eV (bulk value) to 2.1 eV for doped/nanocomposite samples. EPR measurements proved presence of dopant and showed that isolated Fe3+ ions in zirconia matrix exist in both crystalline phases; monoclinic and tetragonal (g ~ 4.8 and g ~ 4.27–4.2, respectively) surroundings. Zirconia samples were also successfully used as photocatalysts for photocatalytic degradation of 2, 4, 6, trichlorophenol. © 2019 Elsevier Ltd and Techna Group S.r.l. |
Biserčić, M S; Marjanović, B; Zasońska, B A; Stojadinović, S; Ćirić-Marjanović, G Novel microporous composites of MOF-5 and polyaniline with high specific surface area Journal Article Synthetic Metals, 262 , 2020. @article{Biserčić2020, title = {Novel microporous composites of MOF-5 and polyaniline with high specific surface area}, author = {M S Biserčić and B Marjanović and B A Zasońska and S Stojadinović and G Ćirić-Marjanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080987780&doi=10.1016%2fj.synthmet.2020.116348&partnerID=40&md5=ce7041b8dbdf75b1f25a95285285ac5c}, doi = {10.1016/j.synthmet.2020.116348}, year = {2020}, date = {2020-01-01}, journal = {Synthetic Metals}, volume = {262}, abstract = {Composites of metal organic framework MOF-5 and conjugated polymer polyaniline (PANI) were synthesized for the first time. Two procedures, which avoid humidity during the synthesis in order to preserve the structure of MOF-5, were applied. In the first one, dissolved part of nonconducting emeraldine base form of PANI (PANI-EB) in N,N΄-dimethylformamide was mixed with MOF-5 in different mass ratios. In the second one, the composites were prepared mechano-chemically, by using powdered conducting emeraldine salt form of PANI (PANI-ES) and solid MOF-5, mixed in chloroform in different mass ratios. The composites were characterized by various techniques: scanning electron microscopy (SEM), FTIR spectroscopy, nitrogen sorption and electrical conductivity measurements, XRD, and flame atomic absorption spectroscopy (FAAS). The procedure which used PANI-EB led to microporous PANI/MOF-5 composites with very high BET specific surface area, SBET (the highest value SBET of c.a. 2700 m2 g−1, even higher than SBET of starting pure MOF-5, showed the composite which contains 89 wt.% of MOF-5) and low conductivity (∼10-7 S cm−1). The second procedure which used PANI-ES gave microporous PANI/MOF-5 composites which showed moderate conductivities (the highest conductivity of 1.0 ⋅ 10−3 S cm-1 exhibited the composite which contains 25 wt.% of MOF-5) and also high SBET values, but lower than those measured for the composites with PANI-EB (the highest SBET of c.a. 850 m2 g-1 showed the composite of PANI doped with HCl which contains c.a. 77 wt.% of MOF-5). XRD measurements confirmed that predominately cubic crystalline structure of MOF-5 was present in almost all composites. © 2020 Elsevier B.V.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Composites of metal organic framework MOF-5 and conjugated polymer polyaniline (PANI) were synthesized for the first time. Two procedures, which avoid humidity during the synthesis in order to preserve the structure of MOF-5, were applied. In the first one, dissolved part of nonconducting emeraldine base form of PANI (PANI-EB) in N,N΄-dimethylformamide was mixed with MOF-5 in different mass ratios. In the second one, the composites were prepared mechano-chemically, by using powdered conducting emeraldine salt form of PANI (PANI-ES) and solid MOF-5, mixed in chloroform in different mass ratios. The composites were characterized by various techniques: scanning electron microscopy (SEM), FTIR spectroscopy, nitrogen sorption and electrical conductivity measurements, XRD, and flame atomic absorption spectroscopy (FAAS). The procedure which used PANI-EB led to microporous PANI/MOF-5 composites with very high BET specific surface area, SBET (the highest value SBET of c.a. 2700 m2 g−1, even higher than SBET of starting pure MOF-5, showed the composite which contains 89 wt.% of MOF-5) and low conductivity (∼10-7 S cm−1). The second procedure which used PANI-ES gave microporous PANI/MOF-5 composites which showed moderate conductivities (the highest conductivity of 1.0 ⋅ 10−3 S cm-1 exhibited the composite which contains 25 wt.% of MOF-5) and also high SBET values, but lower than those measured for the composites with PANI-EB (the highest SBET of c.a. 850 m2 g-1 showed the composite of PANI doped with HCl which contains c.a. 77 wt.% of MOF-5). XRD measurements confirmed that predominately cubic crystalline structure of MOF-5 was present in almost all composites. © 2020 Elsevier B.V. |
Gledovic, A; Lezaic, A J; Krstonosic, V; Djokovic, J; Nikolic, I; Bajuk-Bogdanovic, D; Stankovic, J A; Randjelovic, D; Savic, S M; Filipovic, M; Tamburic, S; Savic, S D PLoS ONE, 15 (4), 2020. @article{Gledovic2020, title = {Low-energy nanoemulsions as carriers for red raspberry seed oil: Formulation approach based on Raman spectroscopy and textural analysis, physicochemical properties, stability and in vitro antioxidant/ biological activity}, author = {A Gledovic and A J Lezaic and V Krstonosic and J Djokovic and I Nikolic and D Bajuk-Bogdanovic and J A Stankovic and D Randjelovic and S M Savic and M Filipovic and S Tamburic and S D Savic}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083478878&doi=10.1371%2fjournal.pone.0230993&partnerID=40&md5=682ff0154174587b10f5581eb48a5b15}, doi = {10.1371/journal.pone.0230993}, year = {2020}, date = {2020-01-01}, journal = {PLoS ONE}, volume = {15}, number = {4}, abstract = {Considering a growing demand for medicinal/cosmetic products with natural actives, this study focuses on the low-energy nanoemulsions (LE-NEs) prepared via the Phase inversion composition (PIC) method at room temperature as potential carriers for natural oil. Four different red raspberry seed oils (ROs) were tested, as follows: cold-pressed vs. CO2- extracted, organic vs. non-organic, refined vs. unrefined. The oil phase was optimized with Tocopheryl acetate and Isostearyl isostearate, while water phase was adjusted with either glycerol or an antioxidant hydro-glycolic extract. This study has used a combined approach to formulation development, employing both conventional methods (pseudo-ternary phase diagram - PTPD, electrical conductivity, particle size measurements, microscopical analysis, and rheological measurements) and the methods novel to this area, such as textural analysis and Raman spectroscopy. Raman spectroscopy has detected fine differences in chemical composition among ROs, and it detected the interactions within nanoemulsions. It was shown that the cold-pressed, unrefined, organic grade oil (RO2) with 6.62% saturated fatty acids and 92.25% unsaturated fatty acids, was optimal for the LE-NEs. Textural analysis confirmed the existence of cubic gel-like phase as a crucial step in the formation of stable RO2-loaded LE-NEs, with droplets in the narrow nano-range (125 to 135 nm; PDI ≤ 0.1). The DPPH test in methanol and ABTS in aqueous medium have revealed a synergistic free radical scavenging effect between lipophilic and hydrophilic antioxidants in LE-NEs. The nanoemulsion carrier has improved the biological effect of raw materials on HeLa cervical adenocarcinoma cells, while exhibiting good safety profile, as confirmed on MRC-5 normal human lung fibroblasts. Overall, this study has shown that low-energy nanoemulsions present very promising carriers for topical delivery of natural bioactives. Raman spectroscopy and textural analysis have proven to be a useful addition to the arsenal of methods used in the formulation and characterization of nanoemulsion systems. © 2020 Gledovic et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Considering a growing demand for medicinal/cosmetic products with natural actives, this study focuses on the low-energy nanoemulsions (LE-NEs) prepared via the Phase inversion composition (PIC) method at room temperature as potential carriers for natural oil. Four different red raspberry seed oils (ROs) were tested, as follows: cold-pressed vs. CO2- extracted, organic vs. non-organic, refined vs. unrefined. The oil phase was optimized with Tocopheryl acetate and Isostearyl isostearate, while water phase was adjusted with either glycerol or an antioxidant hydro-glycolic extract. This study has used a combined approach to formulation development, employing both conventional methods (pseudo-ternary phase diagram - PTPD, electrical conductivity, particle size measurements, microscopical analysis, and rheological measurements) and the methods novel to this area, such as textural analysis and Raman spectroscopy. Raman spectroscopy has detected fine differences in chemical composition among ROs, and it detected the interactions within nanoemulsions. It was shown that the cold-pressed, unrefined, organic grade oil (RO2) with 6.62% saturated fatty acids and 92.25% unsaturated fatty acids, was optimal for the LE-NEs. Textural analysis confirmed the existence of cubic gel-like phase as a crucial step in the formation of stable RO2-loaded LE-NEs, with droplets in the narrow nano-range (125 to 135 nm; PDI ≤ 0.1). The DPPH test in methanol and ABTS in aqueous medium have revealed a synergistic free radical scavenging effect between lipophilic and hydrophilic antioxidants in LE-NEs. The nanoemulsion carrier has improved the biological effect of raw materials on HeLa cervical adenocarcinoma cells, while exhibiting good safety profile, as confirmed on MRC-5 normal human lung fibroblasts. Overall, this study has shown that low-energy nanoemulsions present very promising carriers for topical delivery of natural bioactives. Raman spectroscopy and textural analysis have proven to be a useful addition to the arsenal of methods used in the formulation and characterization of nanoemulsion systems. © 2020 Gledovic et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
Gutić, S J; Dobrota, A S; Fako, E; Skorodumova, N V; López, N; Pašti, I A Hydrogen evolution reaction-from single crystal to single atom catalysts Journal Article Catalysts, 10 (3), 2020. @article{Gutić2020, title = {Hydrogen evolution reaction-from single crystal to single atom catalysts}, author = {S J Gutić and A S Dobrota and E Fako and N V Skorodumova and N López and I A Pašti}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080984156&doi=10.3390%2fcatal10030290&partnerID=40&md5=815f920476b20c05559a8508d08f0ecb}, doi = {10.3390/catal10030290}, year = {2020}, date = {2020-01-01}, journal = {Catalysts}, volume = {10}, number = {3}, abstract = {Hydrogen evolution reaction (HER) is one of the most important reactions in electrochemistry. This is not only because it is the simplest way to produce high purity hydrogen and the fact that it is the side reaction in many other technologies. HER actually shaped current electrochemistry because it was in focus of active research for so many years (and it still is). The number of catalysts investigated for HER is immense, and it is not possible to overview them all. In fact, it seems that the complexity of the field overcomes the complexity of HER. The aim of this review is to point out some of the latest developments in HER catalysis, current directions and some of the missing links between a single crystal, nanosized supported catalysts and recently emerging, single-atom catalysts for HER. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrogen evolution reaction (HER) is one of the most important reactions in electrochemistry. This is not only because it is the simplest way to produce high purity hydrogen and the fact that it is the side reaction in many other technologies. HER actually shaped current electrochemistry because it was in focus of active research for so many years (and it still is). The number of catalysts investigated for HER is immense, and it is not possible to overview them all. In fact, it seems that the complexity of the field overcomes the complexity of HER. The aim of this review is to point out some of the latest developments in HER catalysis, current directions and some of the missing links between a single crystal, nanosized supported catalysts and recently emerging, single-atom catalysts for HER. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. |
Jakovljević, K; Mišljenović, T; Savović, J; Ranković, D; Ranđelović, D; Mihailović, N; Jovanović, S Accumulation of trace elements in Tussilago farfara colonizing post-flotation tailing sites in Serbia Journal Article Environmental Science and Pollution Research, 27 (4), pp. 4089-4103, 2020. @article{Jakovljević20204089, title = {Accumulation of trace elements in Tussilago farfara colonizing post-flotation tailing sites in Serbia}, author = {K Jakovljević and T Mišljenović and J Savović and D Ranković and D Ranđelović and N Mihailović and S Jovanović}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076593326&doi=10.1007%2fs11356-019-07010-z&partnerID=40&md5=3414f7254cbfcb0735e6ba2c973d88c8}, doi = {10.1007/s11356-019-07010-z}, year = {2020}, date = {2020-01-01}, journal = {Environmental Science and Pollution Research}, volume = {27}, number = {4}, pages = {4089-4103}, abstract = {The purpose of this study was to examine the accumulation potential of spontaneously developed Tussilago farfara populations colonizing sites with different levels of anthropogenic pollution. Physical characteristics of the soil are presented, together with the concentrations of macroelements and microelements (Ca, Mg, Fe, S, Al, Pb, Zn, Cu, Cd, Mn, As, Sb, Ag, Ti, and Sr) in both soil and plants. The biological concentration, accumulation, and translocation factors were used to assess the potential for heavy metal accumulation. Considerable differences were found among assessions from unevenly contaminated habitats, particularly in comparison with an unpolluted site. In line with the ore’s characteristics, substrate samples from polluted sites were heavily contaminated with Pb, Zn, As, and Sb. Increased levels of microelements were also detected in plant samples from flotation tailings. Despite active absorption of Zn, Cu, Cd, Mn, and Sr by the plants from mining sites, the detected quantities of these elements in all samples were below the hyperaccumulation threshold. However, the obtained results indicate that the use of T. farfara from such sites in traditional medicine could pose a risk to human health due to accumulation of several toxic elements in the plant’s aboveground tissues. Additionally, as a successful primary colonizer and stabilizer of technogenic substrates, T. farfara has an important role in the initial phases of revegetation of highly contaminated sites. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The purpose of this study was to examine the accumulation potential of spontaneously developed Tussilago farfara populations colonizing sites with different levels of anthropogenic pollution. Physical characteristics of the soil are presented, together with the concentrations of macroelements and microelements (Ca, Mg, Fe, S, Al, Pb, Zn, Cu, Cd, Mn, As, Sb, Ag, Ti, and Sr) in both soil and plants. The biological concentration, accumulation, and translocation factors were used to assess the potential for heavy metal accumulation. Considerable differences were found among assessions from unevenly contaminated habitats, particularly in comparison with an unpolluted site. In line with the ore’s characteristics, substrate samples from polluted sites were heavily contaminated with Pb, Zn, As, and Sb. Increased levels of microelements were also detected in plant samples from flotation tailings. Despite active absorption of Zn, Cu, Cd, Mn, and Sr by the plants from mining sites, the detected quantities of these elements in all samples were below the hyperaccumulation threshold. However, the obtained results indicate that the use of T. farfara from such sites in traditional medicine could pose a risk to human health due to accumulation of several toxic elements in the plant’s aboveground tissues. Additionally, as a successful primary colonizer and stabilizer of technogenic substrates, T. farfara has an important role in the initial phases of revegetation of highly contaminated sites. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. |
Dimić, D; Milanović, Ž; Jovanović, G; Sretenović, D; Milenković, D; Marković, Z; Marković, Dimitrić J Comparative antiradical activity and molecular Docking/Dynamics analysis of octopamine and norepinephrine: the role of OH groups Journal Article Computational Biology and Chemistry, 84 , 2020. @article{Dimić2020, title = {Comparative antiradical activity and molecular Docking/Dynamics analysis of octopamine and norepinephrine: the role of OH groups}, author = {D Dimić and Ž Milanović and G Jovanović and D Sretenović and D Milenković and Z Marković and J Dimitrić Marković}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076515589&doi=10.1016%2fj.compbiolchem.2019.107170&partnerID=40&md5=f368da14eb6e0a988625777d7f81651a}, doi = {10.1016/j.compbiolchem.2019.107170}, year = {2020}, date = {2020-01-01}, journal = {Computational Biology and Chemistry}, volume = {84}, abstract = {Octopamine is a neurotransmitter in invertebrates and a phenol analog of norepinephrine. The crystallographic and spectral (UV–visUV, and NMR) characteristics of octopamine were investigated experimentally and theoretically by applying appropriate level of theory, B3LYP-D3BJ/6-311++G(d,p), which reproduced well the experimental bond lengths and angles. The intramolecular interactions governing the stability of conformers were described by NBO and QTAIM analyses. The antiradical potencies of octopamine and norepinephrine towards DPPH[rad] and ABTS[rad] + were examined with special emphasis on the preferred mechanism and effect of catechol moiety. Several techniques were used to distinguish Hydrogen Atom Transfer (HAT) and Proton Coupled Electron Transfer (PCET) mechanisms for reaction with DPPH[rad]. The calculated rate constants of the reactions with both radicals showed that Sequential Proton Loss Electron Transfer (SPLET) mechanism was dominant both thermodynamically and kinetically, with values of thermodynamic functions and rate constants clearly proving the importance of the second hydroxyl group in structure. The Molecular Docking and afterward Molecular Dynamics calculations of formed complexes between octopamine/norepinephrine with β1- and β2- adrenergic receptors examined in details the interactions that lead to the formation of stable complexes. The number of strong interactions of amino acids with norepinephrine was higher, but the absence of hydroxyl group in octopamine did not lead to a significant change in the type of interactions and stability. The formed complexes showed higher flexibility of amino acids, similar compactness of structure as proteins and increased interatomic distances of the backbone when compared to pure proteins. © 2019 Elsevier Ltd}, keywords = {}, pubstate = {published}, tppubtype = {article} } Octopamine is a neurotransmitter in invertebrates and a phenol analog of norepinephrine. The crystallographic and spectral (UV–visUV, and NMR) characteristics of octopamine were investigated experimentally and theoretically by applying appropriate level of theory, B3LYP-D3BJ/6-311++G(d,p), which reproduced well the experimental bond lengths and angles. The intramolecular interactions governing the stability of conformers were described by NBO and QTAIM analyses. The antiradical potencies of octopamine and norepinephrine towards DPPH[rad] and ABTS[rad] + were examined with special emphasis on the preferred mechanism and effect of catechol moiety. Several techniques were used to distinguish Hydrogen Atom Transfer (HAT) and Proton Coupled Electron Transfer (PCET) mechanisms for reaction with DPPH[rad]. The calculated rate constants of the reactions with both radicals showed that Sequential Proton Loss Electron Transfer (SPLET) mechanism was dominant both thermodynamically and kinetically, with values of thermodynamic functions and rate constants clearly proving the importance of the second hydroxyl group in structure. The Molecular Docking and afterward Molecular Dynamics calculations of formed complexes between octopamine/norepinephrine with β1- and β2- adrenergic receptors examined in details the interactions that lead to the formation of stable complexes. The number of strong interactions of amino acids with norepinephrine was higher, but the absence of hydroxyl group in octopamine did not lead to a significant change in the type of interactions and stability. The formed complexes showed higher flexibility of amino acids, similar compactness of structure as proteins and increased interatomic distances of the backbone when compared to pure proteins. © 2019 Elsevier Ltd |
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 |
Petrusic, I; Viana, M; Zecca, C; Zidverc-Trajkovic, J Dysphasia and Other Higher Cortical Dysfunctions During the Migraine Aura—a Systematic Review of Literature Journal Article Current Pain and Headache Reports, 24 (2), 2020. @article{Petrusic2020, title = {Dysphasia and Other Higher Cortical Dysfunctions During the Migraine Aura—a Systematic Review of Literature}, author = {I Petrusic and M Viana and C Zecca and J Zidverc-Trajkovic}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078214474&doi=10.1007%2fs11916-020-0836-3&partnerID=40&md5=a59ae94050746ce59ab54b5cfee7542b}, doi = {10.1007/s11916-020-0836-3}, year = {2020}, date = {2020-01-01}, journal = {Current Pain and Headache Reports}, volume = {24}, number = {2}, abstract = {Purpose of the Review: Although visual and somatosensory disturbances are the most common migraine aura (MA) symptoms, patients can also experience other symptoms during their MA. The aim of this review is to provide an overview of studies that report symptoms of dysphasia and other higher cortical dysfunctions (HCDs) during MA, as well as to determine the frequency of HCDs. Recent Findings: Five studies met the inclusion criteria, corresponding to 697 patients overall. The most frequently reported HCDs were those of the language group (range 10–53%). The occurrence of visual HCDs was noted in 12–40 patients, somatosensory HCDs in 12–20%, and memory disturbances in 10–22% of the patients during MAs. Summary: MA is associated with a wide range of neurological symptoms, including symptoms of HCD. A better strategy for investigation of the HCD symptoms is needed to correctly stratify patients thus allowing meaningful studies of aura pathophysiology. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Purpose of the Review: Although visual and somatosensory disturbances are the most common migraine aura (MA) symptoms, patients can also experience other symptoms during their MA. The aim of this review is to provide an overview of studies that report symptoms of dysphasia and other higher cortical dysfunctions (HCDs) during MA, as well as to determine the frequency of HCDs. Recent Findings: Five studies met the inclusion criteria, corresponding to 697 patients overall. The most frequently reported HCDs were those of the language group (range 10–53%). The occurrence of visual HCDs was noted in 12–40 patients, somatosensory HCDs in 12–20%, and memory disturbances in 10–22% of the patients during MAs. Summary: MA is associated with a wide range of neurological symptoms, including symptoms of HCD. A better strategy for investigation of the HCD symptoms is needed to correctly stratify patients thus allowing meaningful studies of aura pathophysiology. © 2020, Springer Science+Business Media, LLC, part of Springer Nature. |