Synthesis and characterization of titanium(IV) oxide nanoparticles modified with catecholate and salicylate type ligands: experimental and theoretical (DFT) study

U poslednjih 30 godina nanokristalni TiO2 je privukao veliku paţnju kako kao fotokatalizator za različite praktične primene, tako i kao deo fotohemijskih sistema, kao što je Grecelova ćelija. Zbog svog velikog energetskog procepa (Eg=3,2 eV), TiO2 apsorbuje manje od 5 % dostupnih fotona sunčeve svetlosti, što ga čini relativno neefikasnim fotokatalizatorom. Takođe, glavni energetski gubitak nastaje usled procesa radijativne ili neradijativne rekombinacije naelektrisanja nastalih fotoekscitacijom TiO2, što se manifestuje kao relativno nizak prinos dugo-ţivećih razdvojenih naelektrisanja. Dakle, uspešna fotohemijska konverzija energije i reakcije koje slede zahtevaju produţeno vreme ţivota razdvojenih fotostvorenih naelektrisanja kao i apsorpciju u vidljivom delu spektra...In the last 30 years nanocrystalline TiO2 has attracted widespread attention as a photocatalyst in various practical applications as well as the part of photoelectrochemical systems, such as Grätzel cells. Due to its large band gap (Eg = 3,2 eV), TiO2 absorbs less than 5% of the available solar light photons, being a relatively inefficient photocatalyst. Also, the main energy loss is due to the process of radiative or nonradiative recombination of charges generated upon photoexcitation of TiO2, which is manifested as the relatively low yield of long-lived separated charges. Hence, the successful photochemical energy conversion and subsequent chemical reactions require both the extended lifetime of separated photogenerated charges and the response in the visible spectral region..

Hemijski sastav i biološka aktivnost ekstrakta semena šljive

The aim of this paper was to estimate the biological activity of the plum seed extract and to define the chemical composition by using the ESI-MS method. During the investigation of the antioxidant activity, the extract showed a better ability to inhibit DPPH radicals compared with amygdalin standard. The results of the antimicrobial study indicate that the extract has a greater effect on Gram-negative bacteria compared with amygdalin. Gram-positive bacteria and fungi remained resistant in both cases. Unlike amygdalin, the extract showed a greater antimicrobial activity against the same microbiological strains. Amygdalin was isolated from the extract before the investigation of antiproliferative activity against MDA-MB-361, MDA-MB-453, HeLa and LS174 cell lines using MTT assay. Unlike the MDA-MB-453 cell line, the activity of standard and isolated amygdalin was not observed at the concentrations lower than 400 μg cm-3 on MDA-MB-361 cell line. The isolated amygdalin has not shown the activity in other cell lines. The antiproliferative activity of amygdalin standard was also noticed on HeLa and LS-174 cell lines at the concentrations of 333.27 and 333.17 μg cm-3, respectively.Cilj ovog rada bila je procena biološke aktivnosti ekstrakta semena šljive i definisanje hemijskog sastava primenom ESI-MS metode. Tokom ispitivanja antioksidativne aktivnosti, ekstrakt je pokazao bolju sposobnost inhibiranja DPPH radikala u poređenju sa standardom amigdalina. Rezultati antimikrobne studije pokazali su da ekstrakt ima veći uticaj na rast Gram-negativnih bakterija u odnosnu na amigdalin. Gram-pozitivne bakterije i gljivice ostale su rezistentne u oba slučaja. Za razliku od amigdalina, ekstrakt je pokazao veću antimikrobnu aktivnost na iste sojeve mikroorganizama. Amigdalin je izolovan iz ekstrakta pre ispitivanja antiproliferativne aktivnosti na MDA-MB-361, MDA-MB-453, HeLa i LS174 ćelijskim linijama upotrebom MTT testa. Za razliku od MDA-MB-453 ćelijskih linija, aktivnost standarda i izolovanog amigdalina nije uočena na MDA-MB-361 ćelijskim linijama pri koncentracijama nižim od 400 μg cm-3. Izolovani amigdalin nije pokazao aktivnost na ostalim ćelijskim linijama. Antiproliferativna aktivnost standarda amigdalina uočena je i na HeLa i LS-174 ćelijskim linijama pri koncentracijama 333.27 i 333.17 μg cm-3, respektivno

Optical properties of ZnO/Zn/WO4 composite nanoparticles

ZnO/ZnWO4 composite rod-like nanoparticles were synthesized by lowtemperature soft solution method at 95º C with different reaction times (1-120 hours), in the presence of non-ionic copolymer surfactant Pluronic F68. Optical properties such as reflection and room temperature photoluminescence of obtained samples showed strong dependence on their crystallinity and composition.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Elektrohemijska oksidacija 2,4,6-trihlorfenola na nano-cirkonijum - oksidnoj matrici dopiranoj gvožđem

Solvothermaly synthesized zirconium oxide nanopowders, pure and doped with various amounts of iron ions (1–20 %), were used as modifiers of glassy carbon electrodes. The modified electrodes were tested in the reaction of electrochemical oxidation of 2,4,6-trichlorophenol (TCP) in order to inves tigate the influence of doping on electrochemical performance of zirconia mat rix. The techniques of cyclic voltammetry and electrochemical impedance spectroscopy were employed. Cyclic voltammetry showed that electrooxid ation of TCP proceeded through the oxidation of hydroxyl group. Possible pathway included the formation of quinones and the formation of polyphenol film on the electrode surface, leading to the electrode fouling. Iron doping enhanced the activity of zirconia matrix towards TCP electrooxidation. Elec trochemical impedance spectroscopy showed the importance of iron content in zirconia matrix for the preferable pathway of TCP electrooxidation. The quin one formation pathway was favoured by low iron doped zirconia (doped with 1% of iron), while polyphenol film formation on the electrode surface was more pronounced at samples with higher iron ion content (for doping with 10 and 20 % of iron). The sample with 5 % of added iron ions, showed intermedНанопрахови цирконијум-оксида, чисти и допирани различитим количинама јона гвожђа синтетисани су солвотермалном методом. Добијени прахови су коришћени као модификатори електродa од стакластог угљеника. Модификоване електроде су тести- ране у реакцији електрохемијске оксидације 2,4,6-трихлорфенола (TCP), како би се испитао утицај допанта на перформансе цирконијум-оксидне матрице. За испитивање су коришћене технике цикличне волтаметрије и електрохемијске импедансне спектро- скопије. Резултати цикличне волтаметрије су показали да се електрооксидација TCP одиграва преко оксидације хидроксилне групе. Могуће даље реакционе путање су укљу- чивале формирање хинона и настајање полифенолног филма на површини електроде који доводи до пасивације електроде. Допирање јонима гвожђа је повећало активност цирконијум-оксидне матрице за електрооксидацију TCP. Резултати електрохемијске импедансне спектроскопије су указали на утицај количине јона гвожђа у цирконијум- -оксидној матрици на реакциони механизам TCP електроосидације. Реакциона путања која укључује формирање хинона је фаворизована на цирконијум-оксидним електро- дама са ниским садржајем јона гвожђа (допираног са 1 % јона гвожђа), док је форми- рање полифенолног филма дошло до изражаја на узорцима са већим садржајем јона гвожђа (допираних са 10 и 20 % јона гвожђа). Узорак цирконијум-оксида, допиран са 5 % јона гвожђа, има прелазна својства, јер долази до формирања полифенолног филма на површини електроде, али и до његове разградње

Penile morphology in six populations of Branchipus schaefferi Fischer, 1834 (Crustacea: Branchiopoda) from Serbia

Male genital morphology of six populations of Branchipus schaefferi from different locations in Serbia is described. Both qualitative and quantitative morphological traits were taken into consideration. The majority of males from lowland parts of the country (Pannonian Plane) had a long sickle-curved or arched spine situated on the basal part of the penis. Males sampled in the south-eastern part of the country (the region of Stara Planina Mountains) possessed short, straight or slightly bowed basal spine. A distal penile part appeared as a more stable character than the proximal one. Males from one of the examined populations possessed roundish and spineless penile tip, a feature heretofore not described in B. schaefferi.Acta Zoologica Bulgarica (2017), 69(1): 17-2

Surface modification of zirconia nanoparticles with selected enediol ligands

The colloidal ZrO2 nanoparticles were hydrolytically synthesized and characterized using x-ray diffraction and UV/Vis spectroscopy. The surface modification of nanocrystalline particles with selected enediol ligands: catechol (CAT), 2,3-dihydroxynaphthalene (2,3-DHN), anthrarobin (ANT) and quercetin, was found to alter the optical properties of nanoparticles. The formation of the inner-sphere charge-transfer (CT) complexes results in a red shift of the semiconductor absorption onset compared to unmodified nanocrystallites, and a decrease of effective band gap upon increase of the electron delocalization after the inclusion of additional ring

Synthesis of CdIn2S4 mesocrystals

Ternary nanosized sulfide CdIn2S4was synthesized using hot-injectionmethod in oleic acid/oleylamine mixture as reaction media at 270ºC. TEM images have shown that obtained material grows through multistep process, forming marigold structures built out from mesocrystals. Influence of oleic acid and oleic acid/oleylaminemixture as reaction media on mesocrystal formation is tracked and discussed.Physical chemistry 2016 : 13th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-30 September 201

Supplementary data for the article: Savić, T. D.; Ćomor, M. I.; Abazović, N. D.; Šaponjić, Z. V.; Marinović-Cincović, M. T.; Veljković, D. Ž.; Zarić, S. D.; Janković, I. A. Anatase Nanoparticles Surface Modified with Fused Ring Salicylate-Type Ligands (1-Hydroxy-2-Naphthoic Acids): A Combined DFT and Experimental Study. Journal of Alloys and Compounds 2015, 630, 226–235. https://doi.org/10.1016/j.jallcom.2015.01.041

Supplementary material for: [https://doi.org/10.1016/j.jallcom.2015.01.041]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1661

A comparative antimicrobial and toxicological study of gold(III) and silver(I) complexes with aromatic nitrogen-containing heterocycles: synergistic activity and improved selectivity index of Au(III)/Ag(I) complexes mixture

Five aromatic nitrogen-containing heterocycles, pyridazine (pydz, 1), pyrimidine (pm, 2), pyrazine (pz, 3), quinoxaline (qx, 4) and phenazine (phz, 5) have been used for the synthesis of gold(III) and silver(I) complexes. In contrast to the mononuclear Au1-5 complexes all having square-planar geometry, the corresponding Ag1-5 complexes have been found to be polynuclear and of different geometries. Complexes Au1-5 and Ag1-5, along with K[AuCl4], AgNO3 and N-heterocyclic ligands used for their synthesis, were evaluated by in vitro antimicrobial studies against a panel of microbial strains that lead to many skin and soft tissue, respiratory, wound and nosocomial infections. All tested complexes exhibited excellent to good antibacterial activity with minimal inhibitory (MIC) values in the range of 2.5 to 100 mu g mL(-1) against the investigated strains. The complexes were particularly efficient against pathogenic Pseudomonas aeruginosa (MIC = 2.5-30 mu g mL(-1)) and had a marked ability to disrupt clinically relevant biofilms of strains with high inherent resistance to antibiotics. Moreover, the Au1-4 and Ag1-5 complexes exhibited pronounced ability to competitively intercalate double stranded genomic DNA of P. aeruginosa, which was demonstrated by gel electrophoresis techniques and supported by molecular docking into the DNA major groove. Antiproliferative effect on the normal human lung fibroblast cell line MRC5 has also been evaluated in order to determine therapeutic potential of Au1-5 and Ag1-5 complexes. Since the investigated gold(III) complexes showed much lower negative effects on the viability of the MRC5 cell line than their silver(I) analogues and slightly lower antimicrobial activity against the investigated strains, the combination approach to improve their pharmacological profiles was applied. Synergistic antimicrobial effect and the selectivity index of 10 were achieved for the selected gold(III)/silver(I) complexes mixtures, as well as higher P. aeruginosa PAO1 biofilm disruption activity, and improved toxicity profile towards zebrafish embryos, in comparison to the single complexes. To the best of our knowledge, this is the first report on synergistic activity of gold(III)/silver(I) complexes mixtures and it could have an impact on development of new combination therapy methods for the treatment of multi-resistant bacterial infections.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3334