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Bacterial cellulose (BC) is a promising natural polymer prized for its biocompatibility, microporosity, transparency, conformability, elasticity, and ability to maintain a moist wound environment while absorbing exudates. These attributes make BC an attractive material in biomedical applications, particularly in skin tissue repair. However, its lack of inherent antimicrobial activity limits its effectiveness. In this study, BC was enhanced by incorporating cerium (IV)-oxide (CeO2) nanoparticles, resulting in a series of bacterial cellulose-CeO2 (BC-CeO2) composite materials. Characterization via FESEM, XRD, and FTIR confirmed the successful synthesis of the composites. Notably, BC-CeO2-1 exhibited no cytotoxic or genotoxic effects on peripheral blood lymphocytes, and it additionally protected cells from genotoxic and cytotoxic effects in H2O2-treated cultures. Redox parameters in blood plasma samples displayed concentration and time-dependent trends in PAB and LPP assays. The incorporation of CeO2 nanoparticles also bolstered antimicrobial activity, expanding the potential biomedical applications of these composites.

Bacterial cellulose (BC) is a promising natural polymer prized for its biocompatibility, microporosity, transparency, conformability, elasticity, and ability to maintain a moist wound environment while absorbing exudates. These attributes make BC an attractive material in biomedical applications, particularly in skin tissue repair. However, its lack of inherent antimicrobial activity limits its effectiveness. In this study, BC was enhanced by incorporating cerium (IV)-oxide (CeO2) nanoparticles, resulting in a series of bacterial cellulose-CeO2 (BC-CeO2) composite materials. Characterization via FESEM, XRD, and FTIR confirmed the successful synthesis of the composites. Notably, BC-CeO2-1 exhibited no cytotoxic or genotoxic effects on peripheral blood lymphocytes, and it additionally protected cells from genotoxic and cytotoxic effects in H2O2-treated cultures. Redox parameters in blood plasma samples displayed concentration and time-dependent trends in PAB and LPP assays. The incorporation of CeO2 nanoparticles also bolstered antimicrobial activity, expanding the potential biomedical applications of these composites.

Aromatic plants and laser beam wavelength in the red range of visible spectra (623.8 nm), most commonly used for treating plant species, were selected. As there is not much information in the references, it is necessary to set a scale with qualitative and partially quantitative evaluations of the results. Specimens of thyme seed (Thymus vulgaris) were selected as aromatic plants for studying the effect of low-power lasers on plant development, and continuous He-Ne laser, with irradiation times in the range of minutes.

Crystalline TiO2 has many practical applications as a photocatalytic material. The structures and relative energies of eleven different modifications of bulk structures with TiO2 composition were theoretically investigated in this study. Calculations were performed by the DFT method with LDA-PZ functional as implemented in CRYSTAL17 code. Structural parameters, energy- volume curves and electronic band gaps were calculated and analyzed. This study aimed to gain insight into the electronic structure of various modifications of crystalline pristine TiO2 and their phase transitions especially applicable at extreme pressure and temperature conditions. The information obtained in this study may contribute to future research on the structure and various properties (electronic, mechanical…) of such systems, as well as their potential application in various scientific fields and advanced technology.

Nanometric size Co0.9Ho0.1MoO4 powder particles were obtained by applying glycine nitrate procedure (GNP). Powder properties have been studied by DTA, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, Spectroscopy, Field emission scanning electron microscopy (FESEM), and nitrogen adsorption method. The photocatalytic activity of acquiring Co0.9Ho0.1MoO4 nanopowders was estimated by the photocatalytic degradation of crystal violet in an aqueous solution. We present a simple and effective method for controlling the composition and morphology of Co0.9Ho0.1MoO4, as well as a possible new approach in inorganic synthesis methodology. During photocatalytic testing, the studied nanoparticle powder indicated a potentially promising solution in photocatalytic processes toward green chemistry and sustainable development.

The Cr−Si−N system is of great interest for materials with advanced tribological and mechanical properties. So far, experimental data have been reported on Cr−Si−N coating, nanocrystalline phases, and thin films, together with theoretically predicted 1D and 2D hetero-structures, and 3D bulk Cr2SiN4 modifications. This study predicts possible bulk Cr−Si−N phases with the composition CrSi2N4. A multi-methodological approach has been employed to explore the system's energy landscape, where global optimization was combined with data mining and the Primitive Cell for Atom Exchange (PCAE) method. Local optimization of the structure candidates was performed on the DFT level using the GGA-PBE and the LDA-PZ approximation. The ten energetically most favorable structure candidates discovered in the CrSi2N4 chemical system mostly exhibited monoclinic symmetry but with a variety of structural features, from zeolite-like structures to polytypic behavior. Finally, the bulk modulus of these possible modifications was computed for a pressure range of up to 10 GPa.

Studying the interaction of inorganic systems with organic ones is a highly important avenue for finding new drugs and treatment methods. Tumor cells show an increased demand for amino acids due to their rapid proliferation; thus, targeting their metabolism is becoming a potential oncological therapeutic strategy. One of the inorganic materials that show antitumor properties is titanium dioxide, while its doping was found to enhance interactions with biological systems. Thus, in this study, we investigated the energy landscape of glutamine (L), an amino acid, on pristine and doped TiO2 surfaces. We first locally optimized 2D-slab structures of pristine and Au/Ag/Cu-doped anatase (001 and 101 surfaces) and similarly optimized a single molecule of glutamine in vacuum. Next, we placed the pre-optimized glutamine molecule in various orientations and on a variety of locations onto the relaxed substrate surfaces (in vacuum) and performed ab initio relaxations of the molecule on the substrate slabs. We employed the DFT method with a GGA-PBE functional implemented in the Quantum Espresso code. Comparisons of the optimized conformations and electronic structures of the amino acid in vacuum and on the surfaces yield useful insights into various biological processes.

Calcium carbonate and gypsum are very common and widespread minerals widely used in many fields. However, in order to investigate their behavior under extreme conditions of pressure and temperature, a data-mining ab initio approach has been performed. To analyze structural stability and explore different CaCO3 and gypsum phases in these extreme conditions, the most interesting modifications have been submitted to the DFT calculations. Local optimizations have been performed using the CRYSTAL17 solid-state-quantum-chemical program. Total energies of different gypsum phases are presented and it seems that among the calcite phases, the Calcite I (CaCO3 I) phase has the lowest calculated total energy using the three different functionals in agreement with experimental data. Each of the modified phases of these minerals has been discussed and presented in this study. Due to the very wide industrial and technological application of these natural minerals, further investigation could be of great importance, especially their performances in extreme environments.

Co0.9Ho0.1MoO4 nanopowders were obtained by applying glycine nitrate procedure (GNP). The synthesized samples were investigated by DTA, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, Spectroscopy, Field emission scanning electron microscopy (FESEM), and nitrogen adsorption method. The photocatalytic activity of acquired Co0.9Ho0.1MoO4 nanopowders was estimated by the photocatalytic degradation of crystal violet in aqueous solution. A simple and effective method for controlling the composition and morphology of Co0.9Ho0.1MoO4 is presented in this paper, as well as a potentially new approach in the methodology of inorganic synthesis. During photocatalytic testing nanostructured material Co0.9Ho0.1MoO4 indicated the possibility of a promising solution in photocatalytic processes towards green chemistry and sustainable development.

The nanostructured powderwas synthesized by the glycine nitrate procedure (GNP) because it proved to be the most effective and simplest method suitable for controlling the composition and morphology of Co0.9Ho0.1MoO4. To prepare nanostructured Co0.9Ho0.1MoO4, metal nitrates, and glycine were mixed in appropriate stoichiometric ratios. For the preparation of the technologically important Co0.9Ho0.1MoO4, the combustion process has proven to be a promising method that achieves control of stoichiometry, homogeneity, and purity. The synthesized samples were examined by DTA, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, Spectroscopy, Field emission scanning electron microscopy (FESEM), and nitrogen adsorption method. The acquired nanopowder showed a tendency for agglomeration, inhomogeneous microstructure, and plate-like crystals. The photocatalytic activity of the obtained Co0.9Ho0.1MoO4nanopowders was evaluated by the photocatalytic degradation of crystal violet in an aqueous solution. After photocatalytic testing and all the above-mentioned characterizations, it was shown that these nanostructured materials represent promising solutions in photocatalytic processes toward green chemistry and sustainable development.

The interfacial charge transfer (ICT) complex formation between zirconium dioxide (ZrO2), the material absorbing below 250 nm, and 5-aminosalicylic acid (5-ASA) leads to the formation of visible-light-absorbing inorganic–organic hybrids. The free amino groups, present on the hybrid's surface after the ICT complex formation, were used to reduce silver ions and link silver particles to ZrO2. The prepared samples were characterized by using transmission electron microscopy, X-ray diffraction analysis, and nitrogen adsorption–desorption isotherms. Density functional theory (DFT) calculations using a cluster model are applied to explain optical changes in hybrids, i.e., absorption redshift induced by the ICT complex formation. Decolorization of an organic dye crystal violet (CV), under ultraviolet-C or visible light, was used to compare the photocatalytic ability of the prepared samples. The ICT complex formation transformed ZrO2 into a hybrid material able to induce photocatalytic reactions under exclusive visible light excitation.

The authors regret to inform about an error in the affiliation of the corresponding author in the published version of this article. The correct affiliation of Dr. Bojan Janković should be: University of Belgrade, Department of Physical Chemistry, “Vinča” Institute of Nuclear Sciences – National Institute of the Republic of Serbia, Mike Petrovića Alasa 12–14, P.O. Box 522, 11001 Belgrade, Serbia. The authors would like to apologise for any inconvenience caused.

In this research composite based on zirconia and graphite was synthesized using the sol-gel method. Aim of this research is to activate and increase the photocatalytic activity of ZrO2 by combining with graphite-based material. Our results show that we obtained material that can remove both cationic and anionic dyes by sorption and photocatalytic processes. Obtained composite is very effective in sorption of RB19 with up to 100% removal. Photocatalytic activity of composite is higher than pristine GO and goes up to 100% for RB19 degradation and about 50% degradation of MB. These results are promising and present an excellent base for further research. © 2022, Universitatea Babes-Bolyai, Catedra de Filosofie Sistematica. All rights reserved.

Improving reproducibility and replicability in preclinical research is a widely discussed and pertinent topic, especially regarding ethical responsibility in animal research. INFRAFRONTIER, the European Research Infrastructure for the generation, phenotyping, archiving, and distribution of model mammalian genomes, is addressing this issue by developing internal quality principles for its different service areas, that provides a quality framework for its operational activities. This article introduces the INFRAFRONTIER Quality Principles in Systemic Phenotyping of genetically altered mouse models. A total of 11 key principles are included, ranging from general requirements for compliance with guidelines on animal testing, to the need for well-trained personnel and more specific standards such as the exchange of reference lines. Recently established requirements such as the provision of FAIR (Findable, Accessible, Interoperable, Reusable) data are also addressed. For each quality principle, we have outlined the specific context, requirements, further recommendations, and key references.

Apstrakt—Ljudski osećaj za boje ima mnogo aspekata, počevši od čovekovog poimanja sveta oko sebe, do medicinskih pojmova koji uključuju i daltonizam, ali (u svakodnevici) najpozitivniji, najhumaniji je čovekov osećaj za deo dana ili noći (meseca ili godine), za uživanje u heritološkom blagu, koje su nam ostavili preci, ali ne samo crno-belo. Istraživanja, kojima je procenjivan ljudski vek, postojanje i razvoj humanih bića, kao i nastajanje i evolucija flore i faune, sve ovo mora da bude tretirano multidisciplinarno, bez obzira da li se polazi od stena, stalaktita i stalagmita, morskih dubina, tragova u atmosferi ili potrage za planetom koja je slična Zemlji. U radu se daje nekoliko prilaza boji i kolorimetriji, sa aspekta raznih naučnih disciplina. Prikazuje se uloga lasera u novim problematikama, kvantitativne definicije boje i njenih pokazatelja. U području merenja, daje se prilaz sa aspekta filtera i korektnog opisa stanja i delovanja odabranih filtera sa savremenim izražavanjima rezultata, kao i merne metode. Konstatacija boje i njena deskripcija, ima veliku ulogu u svakodnevnom životu, kao i u pojedinim tehničkim i mass media primenama, uključivši i humanističke i tehničke nauke.

Nanoemulsion technique based on Ouzo effect was applied for the fast and simple synthesis of Ag3PO4 at room temperature. X-ray powder diffraction analysis and Raman spectroscopy reviled that synthesized powder was single-phase. Using scanning electron microscopy analysis, it was found that the synthesized Ag3PO4 particles were near-spherical shape with an average diameter of 100 nm. The high value for the specific surface area of obtained powder was measured by Brunauer–Emmet–Teller method. Finally, the Ag3PO4 product was used as a photocatalyst for the photodegradation of crystal violet dye in an aqueous solution. Nanoemulsion strategy procedure provides a simple pathway to obtain a highly efficient single-phase Ag3PO4 photocatalyst.

Current deep convolutional networks are fixed in their topology. We explore the possibilites of making the convolutional topology a parameter itself by combining NeuroEvolution of Augmenting Topologies (NEAT) with Convolutional Neural Networks (CNNs) and propose such a system using blocks of Residual Networks (ResNets). We then explain how our suggested system can only be built once additional optimizations have been made, as genetic algorithms are way more demanding than training per backpropagation. On the way there we explain most of those buzzwords and offer a gentle and brief introduction to the most important modern areas of machine learning, Comment: Unpublished

The antibacterial performance and cytotoxic examination of in situ prepared silver nanoparticles (Ag NPs), on inorganic-organic hybrid nanopowder consisting of zirconium dioxide nanoparticles (ZrO2 NPs) and dihydroquercetin (DHQ), was performed against Gram (−) bacteria Escherichia coli and Gram (+) bacteria Staphylococcus aureus, as well as against human cervical cancer cells HeLa and healthy MRC-5 human cells. The surface modification of ZrO2 NPs, synthesized by the sol-gel method, with DHQ leads to the interfacial charge transfer (ICT) complex formation indicated by the appearance of absorption in the visible spectral range. The prepared samples were thoroughly characterized (TEM, XRD, reflection spectroscopy), and, in addition, the spectroscopic observations are supported by the density functional theory (DFT) calculations using a cluster model. The concentration- and time-dependent antibacterial tests indicated a complete reduction of bacterial species, E. coli and S. aureus, for all investigated concentrations of silver (0.10, 0.25, and 0.50 mg/mL) after 24 h of contact. On the other side, the functionalized ZrO2 NPs with DHQ, before and after deposition of Ag NPs, do not display a significant decrease in the viability of HeLa MRC-5 cells in any of the used concentrations compared to the control.

The authors regret to inform about an error in the affiliation of the corresponding author in the published version of this article. The correct affiliation of Dr. Bojan Janković should be: University of Belgrade, Department of Physical Chemistry, “Vinča” Institute of Nuclear Sciences – National Institute of the Republic of Serbia, Mike Petrovića Alasa 12–14, P.O. Box 522, 11001 Belgrade, Serbia. The authors would like to apologise for any inconvenience caused.

In this research composite based on zirconia and graphite was synthesized using the sol-gel method. Aim of this research is to activate and increase the photocatalytic activity of ZrO2 by combining with graphite-based material. Our results show that we obtained material that can remove both cationic and anionic dyes by sorption and photocatalytic processes. Obtained composite is very effective in sorption of RB19 with up to 100% removal. Photocatalytic activity of composite is higher than pristine GO and goes up to 100% for RB19 degradation and about 50% degradation of MB. These results are promising and present an excellent base for further research. © 2022, Universitatea Babes-Bolyai, Catedra de Filosofie Sistematica. All rights reserved.

In this research composite based on zirconia and graphite was synthesized using the sol-gel method. Aim of this research is to activate and increase the photocatalytic activity of ZrO2 by combining with graphite-based material. Our results show that we obtained material that can remove both cationic and anionic dyes by sorption and photocatalytic processes. Obtained composite is very effective in sorption of RB19 with up to 100% removal. Photocatalytic activity of composite is higher than pristine GO and goes up to 100% for RB19 degradation and about 50% degradation of MB. These results are promising and present an excellent base for further research.

Spider silk-maghemite (SS-gamma-Fe2O3) composite was obtained by simple and fast co-precipitation method at room temperature. The fibers were coated with maghemite nanoparticles with the average size of 25 nm. According to DTA, maghemite NPs contributed the thermal stability of the composite. Magnetic properties of as obtained composite were estimated. At room temperature, the system was is in a superparamagnetic state, while at temperature of 5 K the magnetic moments were blocked. This composite is seen as a novel hybrid material with superparamagnetic properties for possible applications in bioseparation, biosensors, magnetographic printing, magnetic screens, and magnetic filters as well as sensing/actuating components of MEMS.

U radu su prikazani rezultati četiri različite sorte krompira namenjenih za preradu u čips: Saturna, Madison, Lady Claire i Kiebitz, dobijeni tokom dvogodišnjih ispitivanja u agroekološkim uslovima lokaliteta Sombor i Odžaci kod Trstenika. Analizirani su prinos, dužina vegetacionog perioda, broj krtola po biljci, prosečna masa krtole i udeo pojedinih frakcija. Godine su se razlikovale po temperaturama i sumama padavina u periodu april-septembar, a sorte su različito reagovale na promenjene klimatske uslove. Dužina vegetacionog perioda kod svih sorti bila je veća u Somboru u obe godine u odnosu na Odžake. Sorta Kiebitz se odlikuje najkraćim (u proseku 104 dana) a sorta Saturna najdužim vegetacionim periodom (110 dana). Najveći prosečan prinos imala je sorta Lady Claire (42775 kg/ha), a najmanji Kiebitz (37693 kg/ha). Saturna je imala najveći broj krtola (14,7), a najmanju prosečnu masu krtole (74,3g), dok je najmanji broj krtola imala sorta Kiebitz (10,4), a najveću masu krtola imala je sorta Madison (101,0g). Sorta Saturna se ističe i nepovoljnim udelom frakcija poželjnih za preradu u čips.

Silicon borides represent very appealing industrial materials for research owing to their remarkable features, and, together with other boride and carbide-based materials, have very wide applications. Various Si–B phases have been investigated in the past, however a limited number of studies have been done on the pristine SiB6 compound. Structure prediction using a data mining ab initio approach has been performed in pure silicon hexaboride. Several novel structures, for which there are no previous experimental or theoretical data, have been discovered. Each of the structure candidates were locally optimized on the DFT level, employing the LDA-PZ and the GGA-PBE functional. Mechanical and elastic properties for each of the predicted and experimentally observed modifications have been investigated in great detail. In particular, the ductility/brittleness relationship, the character of the bonding, Young’s modulus E, bulk modulus B, and shear modulus K, including anisotropy, have been calculated and analyzed.

New binary catalytic systems based on sulphated zirconia-alumina were synthesized by controlled hydrolysis of alkoxides using relative molar ratios of constituents 1:1, 1:2 and 1:3 in favour of zirconia. The obtained differences in the final catalytic material’s properties may be related to organic precursor memory effect, the applied calcinations temperatures and used alumina contents. The addition of alumina to zirconia affected the structural and surface properties stabilizing bare zirconia by means of slower phase transformation of tetragonal zirconia crystal phase into monoclinic one, further resulting in smaller crystallites sizes and higher surface density of acidic function (sulphates). The best alumina impact on physico-chemical properties was achieved when the highest amount of alumina (e.g. 50%) and lower calcination temperature (500°C) were used, causing relatively high steady-state activity in isomerization of n-hexane at reaction temperature 250 °C. On the other hand, higher calcination temperature (600 °C) played a role in the genesis of greater sulphate density. Catalytic activity and selectivity are expressed as a complex synergistic function of relative density of acid sites together with positive status of other optimized physico-chemical properties of the catalytic material (by activation and calcination temperatures).

Silicon borides represent very appealing industrial materials for research owing to their remarkable features, and, together with other boride and carbide-based materials, have very wide applications. Various Si–B phases have been investigated in the past, however a limited number of studies have been done on the pristine SiB6 compound. Structure prediction using a data mining ab initio approach has been performed in pure silicon hexaboride. Several novel structures, for which there are no previous experimental or theoretical data, have been discovered. Each of the structure candidates were locally optimized on the DFT level, employing the LDA-PZ and the GGA-PBE functional. Mechanical and elastic properties for each of the predicted and experimentally observed modifications have been investigated in great detail. In particular, the ductility/brittleness relationship, the character of the bonding, Young’s modulus E, bulk modulus B, and shear modulus K, including anisotropy, have been calculated and analyzed.

A visible-light-responsive hybrid material was prepared by surface-modification of γ-Al2O3, an insulator with a bandgap of about 8.7 eV, with 5-aminosalicylic acid (5-ASA), leading to the formation of an interfacial charge transfer (ICT) complex. The microstructural characterization of pristine γ-Al2O3 includes X-ray diffraction analysis, transmission electron microscopy, and nitrogen adsorption-desorption isotherms. The pristine γ-Al2O3 powder consists of agglomerated rod-like nanoparticles ((2-3) × (15-20) nm, diameter × length) with the large specific surface area (~420 m2/g). An enormous absorption red-shift is observed upon the formation of the ICT complex. The absorption onset of the inorganic-organic hybrid was found to be at 730 nm by diffuse reflection spectroscopy. The photocatalytic performance of prepared samples was thoroughly tested using the decolorization of the organic dye crystal violet (CV) under illumination in different spectral regions and different light intensities. Excitation with UV light leads to complete decolorization of CV, while the degradation kinetics are impeded when a visible light source is used. Also, the increase of UV light intensity induced significantly faster degradation kinetics of CV, while the degradation rates of CV are quite insensitive to the increase of visible light intensity.

Boron carbide (B4C) has attracted great attention as a semiconducting material with excellent properties and has found various technological applications. High hardness value makes it a potentially superhard material as well as a low density, high degree of chemical inertness, high melting temperature, thermal stability, abrasion resistance, and excellent neutron absorption, contributed to the use of boron carbide as an abrasive material for extreme conditions, wear resistance components, body armors and as a nuclear absorber or solid-state neutron detector. However, B4C is known for its unusual structure, bonding, and substitutional disordering whose nature is not yet fully understood, and exhibits brittle impact behavior. In this study we investigated the chain-model structure with an arrangement of 12-boron atom icosahedra and linear 3-carbon atom chains, using available experimental data. We employed the DFT method with LDA and GGA- PBE functional, as implemented in the CRYSTAL17 software package. Electronic properties of boron carbide have been investigated by calculating the density of states (DOS) and band structure. Calculated mechanical properties have been investigated: bulk modulus, shear modulus, Young modulus, Poisson’s ratio, hardness, and elastic tensor constants, and compared with available experimental data.

A glassy carbon electrode was functionalized by MoO2 nanoparticle–decorated multiwalled carbon nanotubes (MWCNTs) and examined as a working electrode in oxyfluorfen (OXY) detection by differential pulse stripping voltammetry (DPSV). Measurement parameters were as follows: initial potential − 0.1 V, end potential + 0.5 V, accumulation potential − 0.15 V, accumulation time 80 s, and scan rate 50 mV s−1. A stripping potential of + 0.315 V vs. Ag/AgCl was employed. The pPesticide oxyfluorfen was determined in model samples by DPSV with good reproducibility (RSD <2.4%) in the concentration range 2.5 to 34.5 ng mL−1, with r = 0.99 and a limit of detection of 1.5 ng mL−1. These results are in the same range as those of HPLC/DAD, which is used as the comparative method. Recovery for OXY determination in a real river water sample was 102%. Analyses in Briton-Robinson buffer has shown to be pH dependent with the best response at pH 6.0. Structural characterization of MoO2-MWCNT by Raman spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray crystallography revealed a preserved MWCNT structure decorated with firmly attached clusters of MoO2 nanoparticles.

Phototrophic microorganisms from two caves in Serbia (Podpeć and Stopić) were examined. Samples were taken from the entrances where natural light was present, as well as from the inside caves near artificial light (lampenflora community). Cyanobacteria, Chlorophyta, Bacillariophyta and Xanthophyta were documented, with 51 taxa in total. The highest number of taxa recorded in the Cyanobacteria were coccoid cyanobacteria; Gleocapsa and Chroococcus were dominant. According to the redundancy analysis (RDA), Cyanobacteria were dominant at cave entrances while other groups (Chlorophyta, Bacillariophyta and Xanthophyta) were documented in lampenflora samples. Temperature, relative humidity, and light intensity were measured, as well as chlorophyll a concentrations and biofilm parameters (water, organic and inorganic matter content). Ecological parameters did not show significant variation, while light intensity de-pended on the position of sampling sites. RDA showed that the water content was higher in biofilm samples from cave entrances, while levels of inorganic matter were increased in lampenflora samples. The concentration of chlorophyll a did not show significant correlations with any of the measured ecological or biofilm parameters. Although the ecological parameters inside the cave did not show significant variation, they should be monitored because of the potential influence on the development of the lampenflora community that has a negative aesthetic impact on cave formations.

Boron carbide (B4C) has attracted great attention as a semiconducting material with excellent properties and has found various technological applications. High hardness value makes it a potentially superhard material as well as a low density, high degree of chemical inertness, high melting temperature, thermal stability, abrasion resistance, and excellent neutron absorption, contributed to the use of boron carbide as an abrasive material for extreme conditions, wear resistance components, body armors and as a nuclear absorber or solid-state neutron detector. However, B4C is known for its unusual structure, bonding, and substitutional disordering whose nature is not yet fully understood, and exhibits brittle impact behavior. In this study we investigated the chain-model structure with an arrangement of 12-boron atom icosahedra and linear 3-carbon atom chains, using available experimental data. We employed the DFT method with LDA and GGA- PBE functional, as implemented in the CRYSTAL17 software package. Electronic properties of boron carbide have been investigated by calculating the density of states (DOS) and band structure. Calculated mechanical properties have been investigated: bulk modulus, shear modulus, Young modulus, Poisson’s ratio, hardness, and elastic tensor constants, and compared with available experimental data.

A glassy carbon electrode was functionalized by MoO2 nanoparticle–decorated multiwalled carbon nanotubes (MWCNTs) and examined as a working electrode in oxyfluorfen (OXY) detection by differential pulse stripping voltammetry (DPSV). Measurement parameters were as follows: initial potential − 0.1 V, end potential + 0.5 V, accumulation potential − 0.15 V, accumulation time 80 s, and scan rate 50 mV s−1. A stripping potential of + 0.315 V vs. Ag/AgCl was employed. The pPesticide oxyfluorfen was determined in model samples by DPSV with good reproducibility (RSD <2.4%) in the concentration range 2.5 to 34.5 ng mL−1, with r = 0.99 and a limit of detection of 1.5 ng mL−1. These results are in the same range as those of HPLC/DAD, which is used as the comparative method. Recovery for OXY determination in a real river water sample was 102%. Analyses in Briton-Robinson buffer has shown to be pH dependent with the best response at pH 6.0. Structural characterization of MoO2-MWCNT by Raman spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray crystallography revealed a preserved MWCNT structure decorated with firmly attached clusters of MoO2 nanoparticles.

Phototrophic microorganisms from two caves in Serbia (Podpeć and Stopić) were examined. Samples were taken from the entrances where natural light was present, as well as from the inside caves near artificial light (lampenflora community). Cyanobacteria, Chlorophyta, Bacillariophyta and Xanthophyta were documented, with 51 taxa in total. The highest number of taxa recorded in the Cyanobacteria were coccoid cyanobacteria; Gleocapsa and Chroococcus were dominant. According to the redundancy analysis (RDA), Cyanobacteria were dominant at cave entrances while other groups (Chlorophyta, Bacillariophyta and Xanthophyta) were documented in lampenflora samples. Temperature, relative humidity, and light intensity were measured, as well as chlorophyll a concentrations and biofilm parameters (water, organic and inorganic matter content). Ecological parameters did not show significant variation, while light intensity de-pended on the position of sampling sites. RDA showed that the water content was higher in biofilm samples from cave entrances, while levels of inorganic matter were increased in lampenflora samples. The concentration of chlorophyll a did not show significant correlations with any of the measured ecological or biofilm parameters. Although the ecological parameters inside the cave did not show significant variation, they should be monitored because of the potential influence on the development of the lampenflora community that has a negative aesthetic impact on cave formations.

Within this doctoral dissertation, spider silk fibers have been chosen as a model system for synthesis new composite materials. The fibers were used as a template for biomineralization, coating with different nanoparticles, as well as template for synthesis pure inorganic fibers. By imitating biomineralization process, fibers coated with pure and Eu3+ doped cerium(IV)-oxide (CeO2) were obtained. Based on the experimental results obtained by scanning electron microscopy, the optimal concentration of starting material for subsequent europium doping has been determined. Besides complete physico-chemical characterization of the material, luminescent properties of composite material coated with europium doped ceria were investigated. Similarly, fibers coated with γ-Fe2O3 nanoparticles were obtained by precipitation treatment. Complete physico-chemical, as well as magnetic properties were explored. By calcination of magnesium salts in the presence of spider silk fibers, fiber-shaped magnesium oxide was obtained, while dimensions of materials were defined with dimensions of natural fibers. By subsequent calcination of MgO fibers, magnesium-hydroxide (Mg(OH)2) was formed, while different obtaining parameters like temperature and incubation period were examined. Additionally, within dissertation, theoretical calculations of CeO2 system were done in order to estimate its electronic, elastic and mechanical properties in function of pressures in the range 0-100 GPa.

This dissertation is a part of the research performed within the Grant No. TR 34008. The experimental part of this thesis was done in the Laboratory for applied and industrial chemistry, Department of Chemistry, Faculty of Sciences and Mathematics, University of Niš. Some analyses were done at the Faculty of Engineering and Science, University of Greenwich, UK and the Faculty of Technology in Leskovac, University of Niš. The aim of this doctoral dissertation is the synthesis of new biosorbents by chemical modification of various lignocellulosic materials with Al2O3. Three lignocellulosic biomasses of different origin were used: waste oak wood chips and two types of agro--industrial waste (gourd shell and plum stone). In addition, to increase sorption capacity and the ability for removal of different types of pollutants, chemical modification overcome the differences in the origin and composition of lignocellulose biomasses and the final materials have the same sorption characteristics. The chemical modification of lignocellulosic materials with Al2O3 leads to the creation of new specific active centers on the surface of the biosorbent, where different types of pollutants can be bound (cationic, anionic and nonpolar). By analyzing the principal parameters of the sorption process, the optimal conditions for removal of pollutants from water in the single--component solution, and also simultaneously in the multi--component system, were determined.

Potrošačke navike, nameću i nove trendove u selekciji paprika. Sorte paprika dugih, crvenih plodova, namenjenih preradi su veoma popularne u ovom delu Evrope. U dvogodišnjem periodu ispitivane su četiri domaće sorte paprika slonovo uvo, prizrenka, emina i slonova noga u tipu kanije (kapije). Značajno veću prosečnu masu ploda kao i randman ploda u odnosu na vrednost drugih sorti imala je sorta slonova noga (275,15 g). Debljina perikarpa se kretala od 4,30 (prizrenka) do 6,28 mm (slonovo uvo). Kod sorti slonovo uvo i slonova noga zabeležene su najmanje i najveće vrednosti za ukupno rastvorljivu suvu materiju (4,03 odnosno 5,77%), pri čemu se sorte nisu značajno razlikovale. Ispitivani parametri nisu se značajno razlikovali po godinama. Sorte slonovo uvo i slonova noga, se na osnovu analizairanih osobina mogu preporučiti kao sorte sa najkvalitetnijim plodovima.

This dissertation is part of the research performed within the project ON 172061. Laboratories used: Laboratory for Applied and industrial chemistry and Laboratory for organic analysis and synthesis of the Department of Chemistry of the Faculty of Science and Mathematics in Nis, Laboratory of the Faculty of Technology in Novi Sad and Laboratories of the Institute for nuclear sciences "Vinca", University of Belgrade. The aim of this doctoral dissertation is chemical synthesis of the Al2O3-based catalyst in the form of powder. The catalysts were synthesized by modified (sol-gel, reflux and hydrothermal) method. In addition, the chemical modification of the catalyst based on Al2O3 was carried out with the selected dopant/modificator (KI). The optimal conditions for the synthesis, modification and activation of the catalyst, as well as the selection of precursors for the synthesis of the catalyst (aluminum-isopropoxide and aluminum-trisecbutoxide), were examined. Complete physico-chemical characterization of synthesized catalysts was performed (analysis of textural, structural, morphological, thermal and surface properties of catalysts). The catalysts were tested in the reaction of transesterification of sunflower oil with methanol. The influence of a large number of process parameters (reaction temperature, pressure, velocity and type of mixing, mass fraction of the catalyst, molar ratio of reactants, influence of co-solvent(s), etc.) on the reaction yield were studied. The kinetics of the reaction, the reuse of the catalyst, catalyst regeneration and the stability of the catalyst were examined. The physicochemical characteristics of the synthesized catalytic materials have been correlated to the catalytic activity in the reaction of transesterification of sunflower oil.

Тhe aim of this dissertation was the development of new cationic sorbents, based on a modified lignocellulosic precursor (shell of L. vulgaris as a cheap and easily available plant material), intended for the removal of anionic pollutants from water, primarily phosphate and nitrate as the causative agents of eutrophication. Two original cationic sorbents (KALV and LVAT-CTAC), obtained by the developed procedures (chemical synthesis and surfactant grafting, respectively), were characterized using different methods (CHNS/O, pHPZC, FTIR, SEM-EDS). Sorption tests have shown that both sorbents can be used to remove phosphate and nitrate from the aqueous solutions. Sorbent LVAT-CTAC (based on surfactant) resulted in a maximum removal efficiency of 46% for phosphate, and 22% for nitrate. Sorbent KALV (based on ammonium agent) showed greater removal efficiency of investigated anions (88% for phosphate, and 79% for nitrate). Under optimal conditions, the maximum sorption capacity of KALV for phosphate was 17.85 mg/g, and 16.53 mg/g for the sorption of nitrate. The sorption process is complex in nature (ionic exchange and physical sorption), and takes place in a mixed reaction-diffusion regime. The kinetics of the anions sorption indicates that the results are the best fitted with the non-linear pseudo first-order model. The equilibrium study shows that the phosphate sorption can be best described by Freundlich and Sips isotherms, while the nitrate sorption is better described by Langmuir and Sips models. Thermodynamic parameters confirm that the anions sorption is exothermic and spontaneous in the temperature range of 20-40 oC. At higher temperatures, desorption of the anions from the sorbent surface is favored. The effect of coexisting anions in the solution on the sorption capacity of KALV decreases in the order of: H2PO4->NO3->SO42->Cl-. The possibility of regeneration and reuse of KALV sorbent was confirmed through five consecutive cycles of the sorption/desorption proce

Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase) as well as magnesium hydroxide (Mg(OH)2, brucite) fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2) in the presence of the spider silk fibers, while magnesium hydroxidefibers were synthesized by hydration of MgO fibers at 50 °C, 70°C and 90 °C, for 48 and 96 h. According to Scanning electron microscopy (SEM), dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH)2 fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH)2 fibers was noticed to be covered with brucite in a form of plates. X-ray diffraction (XRD) analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained), while Mg(OH)2 fibers were two- or single-phased brucite depending on incubation period, and/or incubation temperature., Vlakna paukove mreže sakupljena od Pholcus phalangioides pauka korišćena su kao matrica za dobijanje vlakana magnezijum oksida (MgO, periklas) i magnezijum-hidroksida (Mg(OH)2, brucit). Vlakna magnezijum oksida jednostavno su dobijena termičkim razlaganjem soli magnezijuma (MgCl2) u prisustvu vlakana paukove mreže, dok su vlakna magnezijum hidroksida sintetisana hidratacijom MgO vlakana na temperaturama: 50, 70 i 90 °C u trajanju od 48 i 96 h. Na osnovu rezultata skenirajuće elektronske mikroskopije (SEM), veličina sintetisanih MgO vlakana bila je određena dimenzijama vlakana pauka, dok je za Mg(OH)2 vlakna prosečan dijametar rastao sa produženjem perioda hidratacije. Na površini Mg(OH)2 vlakana uočeni su tabličasti kristali brucita. Difrakcija X zraka (XRD) pokazala je da su vlakna periklasa jednofazna (dobijen je čist magnezijum-oksid), dok su brucitna vlakna bila dvofazna ili jednofazna, u zavisnosti od inkubacionog perioda i/ili teperature na kojoj je vršena inkubacija.

Three types of functional ceramic composites were designed, synthesized and probed for effective sulfide removal from aqueous solutions. The main goal was to examine complex influence of graphite, surpluses of Fe (similar to 4%) and micro-additions of Cu (similar to 0.2%) on the functional features of the composites. The structural, textural, morphological and surface characteristics of the composites were examined in detail by XRD, nitrogen sorption, SEM and FTIR. It has been shown that all composites are solid heterogeneous systems containing amorphous and crystalline phases (graphite, hematite, montmorillonite, quartz, etc.) with pronounced redox activity in contact with sulfide aqueous solutions. Great enhancment of sulfide consumption was detected for composites which contained graphite and it was established that reaction kinetics is fitted to irreversible second-order batch reaction with two reactants. After the treatment of 1 mM S2- solution, using composite dossage of 1 g/dm(3), concentration dropped down to 0.02 mM. In addition, cyclic voltammetry at 50 mV/s revealed the key role of dopants in electrochemical aspect of the process. Obvious boost of S2- uptake is ascribed to numerous electrochemical, chemical and sorption processes on the composite's developed surface.

The synthesis route by solution combustion, a glycine nitrate procedure (GNP) of CoMoO4 nanopowders by a glycine as a fuel and as a complexant was examined concerning the photocatalytic aspects and powder characteristics. The synthesized samples were investigated by differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Ultraviolet-Visible (UV/Vis) spectroscopy and nitrogen adsorption method. In this work, we presented a simple and effective method for controlling the composition and morphology of CoMoO4. A single-phase a and 13 crystalline form of CoMoO4 compound was confirmed by X-ray diffraction (XRD). The photocatalytic activity of CoMoO4 nanopowders was estimated by the photocatalytic degradation of crystal violet in aqueous solution. In addition, the obtained specific CoMoO4 nanopowder demonstrated acceptable specific surface area, which can be of particular importance for the photocatalytic processes.

Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase) as well as magnesium hydroxide (Mg(OH)2, brucite) fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2) in the presence of the spider silk fibers, while magnesium hydroxidefibers were synthesized by hydration of MgO fibers at 50 °C, 70°C and 90 °C, for 48 and 96 h. According to Scanning electron microscopy (SEM), dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH)2 fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH)2 fibers was noticed to be covered with brucite in a form of plates. X-ray diffraction (XRD) analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained), while Mg(OH)2 fibers were two- or single-phased brucite depending on incubation period, and/or incubation temperature., Vlakna paukove mreže sakupljena od Pholcus phalangioides pauka korišćena su kao matrica za dobijanje vlakana magnezijum oksida (MgO, periklas) i magnezijum-hidroksida (Mg(OH)2, brucit). Vlakna magnezijum oksida jednostavno su dobijena termičkim razlaganjem soli magnezijuma (MgCl2) u prisustvu vlakana paukove mreže, dok su vlakna magnezijum hidroksida sintetisana hidratacijom MgO vlakana na temperaturama: 50, 70 i 90 °C u trajanju od 48 i 96 h. Na osnovu rezultata skenirajuće elektronske mikroskopije (SEM), veličina sintetisanih MgO vlakana bila je određena dimenzijama vlakana pauka, dok je za Mg(OH)2 vlakna prosečan dijametar rastao sa produženjem perioda hidratacije. Na površini Mg(OH)2 vlakana uočeni su tabličasti kristali brucita. Difrakcija X zraka (XRD) pokazala je da su vlakna periklasa jednofazna (dobijen je čist magnezijum-oksid), dok su brucitna vlakna bila dvofazna ili jednofazna, u zavisnosti od inkubacionog perioda i/ili teperature na kojoj je vršena inkubacija.

Three types of functional ceramic composites were designed, synthesized and probed for effective sulfide removal from aqueous solutions. The main goal was to examine complex influence of graphite, surpluses of Fe (similar to 4%) and micro-additions of Cu (similar to 0.2%) on the functional features of the composites. The structural, textural, morphological and surface characteristics of the composites were examined in detail by XRD, nitrogen sorption, SEM and FTIR. It has been shown that all composites are solid heterogeneous systems containing amorphous and crystalline phases (graphite, hematite, montmorillonite, quartz, etc.) with pronounced redox activity in contact with sulfide aqueous solutions. Great enhancment of sulfide consumption was detected for composites which contained graphite and it was established that reaction kinetics is fitted to irreversible second-order batch reaction with two reactants. After the treatment of 1 mM S2- solution, using composite dossage of 1 g/dm(3), concentration dropped down to 0.02 mM. In addition, cyclic voltammetry at 50 mV/s revealed the key role of dopants in electrochemical aspect of the process. Obvious boost of S2- uptake is ascribed to numerous electrochemical, chemical and sorption processes on the composite's developed surface.

The synthesis route by solution combustion, a glycine nitrate procedure (GNP) of CoMoO4 nanopowders by a glycine as a fuel and as a complexant was examined concerning the photocatalytic aspects and powder characteristics. The synthesized samples were investigated by differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Ultraviolet-Visible (UV/Vis) spectroscopy and nitrogen adsorption method. In this work, we presented a simple and effective method for controlling the composition and morphology of CoMoO4. A single-phase a and 13 crystalline form of CoMoO4 compound was confirmed by X-ray diffraction (XRD). The photocatalytic activity of CoMoO4 nanopowders was estimated by the photocatalytic degradation of crystal violet in aqueous solution. In addition, the obtained specific CoMoO4 nanopowder demonstrated acceptable specific surface area, which can be of particular importance for the photocatalytic processes.

Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase) as well as magnesium hydroxide (Mg(OH)(2), brucite) fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2) in the presence of the spider silk fibers, while magnesium hydroxide fibers were synthesized by hydration of MgO fibers at 50, 70 and 90 degrees C, for 48 and 96 h. According to Scanning electron microscopy (SEM), dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH)(2) fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH)(2) fibers was noticed to be covered with brucite in a form of plates. X-Ray diffraction (XRD) analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained), while Mg(OH)(2) fibers were two-or single-phased brucite depending on incubation period, and/or incubation temperature.

New rules connected with gasoline have banned many additives, so it is becoming increasingly difficult to maintain a high octane value of the fuel while simultaneously respecting the imposed limitations. Thus the reactions of n-alkane isomerization to yeild higher octane numbers gasolines have increased importance. Biodiesel is widely used as a fossil diesel substitute, mainly because of its ecological value and because there is no need for changing the existing motors in any way. However, industrial production of biodiesel still suffers from a number of ecological and economical setbacks. Q4.16.01 - Izdawe 1 ZrO2 is a catalyst which is widely used in industry, mainly because of its favorable textural, structural, morphological and surface properties. It can easily be modified with acidic groups and metals. The catalyst modified in such a way has shown certain properties which make it suitable for use in (in)directly petrochemically important industrial processes such as isomerization of n-alkanes and transesterification of vegetable oils. In this dissertation, ZrO2 was modified with sulfates and phosphates and then characterized in detail and its properties were compared to the unmodified catalyst. Catalyst samples were tested in the reactions of isomerization of n-pentane and n-hexane, as well as the reaction of transesterification of sunflwoer oil with methanol. Reactions were performed under a wide range of conditions in order to determine the influence of a large number of reacton parameters on the flow and yield of the reaction. Kinetics of reactions were also examined and stability of the acid groups on the catalyst surface was determined under realistic conditions. Catalyst properties were then correlated with their activities in order to determine the influence that the particular property has on the efficiency of the catalyst and thus its yield.

The aim of this doctoral dissertation is chemical synthesis of titania based catalyst in forms of thin film and powder. Catalysts in the form of a thin film were prepared by the dip coating technique using an evaporation-induced, self-assembly method (EISA), with the use of selected polymers as a template (Pluronic F127 and PSM02). Titania based catalysts in powder form were prepared by modified sol-gel method. Catalysts were then modified with a selected dopant (ZrO2). The effects of various process parameters during the synthesis process of the catalysts were studied such as: pH value, calcination temperature etc. In addition, a number of key parameters in the preparation of TiO2 in the form of thin film as well as the (gas) atmosphere for the activation of the catalyst were also considered. Q4.16.01 - Izdawe 1 A complete physico-chemical characterization of photocatalysts (investigation of textural, structural, morphological, thermal, surface properties of the catalysts) was performed. The catalysts were tested in the reactions of the photocatalytic degradation and/or conversion of selected dyes (methylene blue and crystal violet) and the degradation and/or conversion of the selected pesticide (2,4- dichlorophenoxyacetic acid). Various process parameters were investigated such as: the impact of the initial concentrations of pollutants, the number of repeated cycles of reaction, the catalyst amounts, the wavelength of radiation, duration of UV irradiation treatment, pH of the tested solution in order to optimize the process parameters. In addition, the antimicrobial activity, against selected bacterial species, of the synthesized TiO2-based materials in the form of powder and thin film was investigated. The obtained results were discussed in order to determine the optimum process parameters of the photocatalytic reactions, and to achieve a more favorable degradation effect or conversion of pollutants. Physico-chemical characteristics of the obtained catalyst mater