Optical energy bandgap tuning of spinel zinc stannate by erbium/ytterbium doping

This work shows the results of an optical energy bandgap (Eg) investigation supported by scanning electron microscopy (SEM) of spinel-type zinc stannate (Zn2SnO4) upon doping with rear earth (RE3+) ions (Er3+, Yb3+). The powder samples are synthesized by a mechanochemical solid-state method with the final annealing step at 1200 C. The reference Zn2SnO4 powder sample bandgap (3.87 eV) turning lower upon doping, precisely to 3.5 eV, and 3.37 eV bandgap values found for Er-doped Zn2SnO4 and Er,Yb-codoped Zn2SnO4 powder samples, respectively is a confirmation of the successful incorporation of the RE3+ ions into the Zn2SnO4 host structure. Morphology of the obtained powders shows, in general, the non-uniformly shaped agglomerates, while their particle sizes follow up the bandgap decreasing trend with doping

Anatomy of the Painting: The Study of the Serbian Orthodox Icon from the Turn of the Seventeenth to the Eighteenth Century

The paper presents the results of the multi-analytical study of the painting on a panel from the icon collection of the Gallery of Matica srpska museum in Novi Sad, Serbia. It is part of the research aiming to set the methodology for the museum’s database on artistic materials and techniques present in the collection. Computer tomography (CT) scanning was used to understand the structure of the wooden panel support. Ultraviolet (UV) and infrared (IC) imaging, as well as visible (VIS) macro photography, were used to study the paint layer, both the original part and restoration treatments, as well as the coat of varnish. Energy dispersive X-ray fluorescence (EDXRF) and Fourier-transform infrared (FTIR) spectroscopy revealed the pigments, binders, and metal leaf, defining the artistic technique. Optical microscopy (OM) and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) were used to disclose the stratigraphy and composition of layers in the artwork. The multi-analytical approach confirmed that protein-based binder, gilding, silver leaf, and traditional pigments were used. The data gathered from this research are important for studying the artistic materials and techniques in icon production and defining the methodology setting for the museum collection’s databases as the reference material

INVESTIGATION OF REACTION CONDITIONS ON SYNTHESIS OF STEROIDAL BROMOHYDRIN AND STRUCTURAL ANALYSIS OF NOVEL 6α-BROM-5β-HYDROXY DERIVATIVE

Reaction conditions variation and its influence on the reaction of 3β-acetoxy-17-oxa-17a-homoandrost-5-en-16-one with in situ generated hypobromous acid was investigated. Hypobromous acid was generated from N-bromoacetamide or N­bromosuccinimide and perchloric acid, and as solvent dioxane, dimethoxyethane or tetrahydrofuran were used. After a series of experiments, it was determined that the number of the reaction products depends on the reagent used, solvents, perchloric acid concentration and the presence/absence of daylight. It has also been found that the yields of certain compounds depend also on the reaction time and temperature. 6α-Bromo-5β-hydroxy derivate is obtained by usage of NBA and 0.28 M perchloric acid in dioxane on daylight. Its structure was confirmed by NMR and X-ray crystal structure analysis. HIGHLIGHTSIn the reaction of a steroidal alkene with in situ generated hypobromous acid, reaction conditions variation affects number and yields of obtained compounds.Most often, 5α-bromo-6β-hydroxy 2, 5β,6β-epoxy 3 and 5α,6β-dibromo 4 compounds are obtained.6α-Bromo-5β-hydroxide 5 and 3β,6β-diacetate 6 are obtained with NBA, 0.28 M HClO4, dioxane and in the presence of daylight at room temperature.Configuration on C5 and C6 of compound 5 was determined by NMR and X­Ray analysis

Multianalytical Study of the Blue Pigments Usage in Serbian Iconography at the Beginning of the 18th-Century

Traditional Serbian religious art originated in Byzantine culture and conserved Byzantine elements until modern times. However, since the end of the 17th century, many changes in traditional icon painting have been introduced. Previous studies focused on the changes in iconography and style, but very little attention was paid to the changes in painting materials and techniques. This research focuses on the blue pigments on icons from the first half of the 18th century. Eight icons with blue areas of a different hue were selected for the study. Due to its rarity in nature, price, and iconographical importance, the blue pigment was particularly praised by painters. Therefore, the choice of the blue pigment can be related to historical information to trace influences and the development of the painter’s practice. Imaging techniques, several portable, non-destructive analytical techniques, such as XRF and FTIR, followed by optical microscopy and SEM-EDX analysis of the samples were used to characterize blue pigments and the painting technique. An analysis showed that icon painters at the beginning of the 18th century used pigments such as azurite, an indigo-organic colourant of plant origin, and Prussian blue. Contrary to the traditional belief that natural ultramarine blue was used, it was not confirmed in any studied examples

Structural and computational study of quinoline-based chalcogensemicarbazones

Chalcogensemicarbazones are condensation products between semicarbazide and its sulphur and selenium isosters with carbonyl compounds with a broad spectrum of biological activities [1-3]. In this work the X-ray structural investigation of library of six chalcogensemicarbazones has been complemented with computational study of their global and local reactive properties, within the framework of density functional theory (DFT). Among other information, DFT calculations helped us to locate the most reactive sites of studied molecules and to identify their sensitivity towards the oxidation. Investigated compounds have been also checked for their optoelectronic properties, due to the fact that they share certain structural similarity with molecules that have exhibited potentially important properties for the area of organic electronics. Pharmacokinetic properties have been assessed by the analysis of frequently employed drug likeness parameters

Supplementary data for article: Filipović, N. R.; Borna, M.; Klisurić, O.; Pregelj, M.; Jagodić, M.; Anđelković, K. K.; Todorović, T. Synthesis, Characterization, and Thermal Behavior of Cu(II) and Zn(II) Complexes with (E)-2-[N-(1-Pyridin-2-Yl-Ethylidene)Hydrazino]Acetic Acid (AphaOH). Crystal Structure of [Zn-2(AphaO)(2)Cl-2]. Journal of Coordination Chemistry 2013, 66 (9), 1549–1560. https://doi.org/10.1080/00958972.2013.786052

Supplementary material for: [https://doi.org/10.1080/00958972.2013.786052]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1639

Supplementary data for the article: Filipović, N. R.; Bjelogrlić, S.; Portalone, G.; Pelliccia, S.; Silvestri, R.; Klisurić, O.; Senćanski, M.; Stanković, D.; Todorović, T. R.; Muller, C. D. Pro-Apoptotic and pro-Differentiation Induction by 8-Quinolinecarboxaldehyde Selenosemicarbazone and Its Co(III) Complex in Human Cancer Cell Lines. MedChemComm 2016, 7 (8), 1604–1616. https://doi.org/10.1039/c6md00199h

Supplementary material for: [https://doi.org/10.1039/c6md00199h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2293]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3598

Determination of 17α-hydroxylase-C_17,20-lyase (P450_17α) enzyme activities and their inhibition by selected steroidal picolyl and picolinylidene compounds

17α-hydroxylase-C17,20-lyase (P45017α) is a key regulator enzyme of the steroid hormone biosynthesis in both the adrenals and the testes. Inhibition of this enzyme can block androgen synthesis in an early step, and may thereby be useful in the treatment of several androgen-dependent diseases. We developed radio-substrate in vitro incubation methods for the determination of the distinct 17α-hydroxylase and C17,20-lyase activities of the enzyme using rat testicular homogenate as enzyme source. With this method we have studied the inhibiting activity of selected steroidal picolyl and picolinylidene compounds. Tests revealed a substantial inhibitory action of the 17-picolinyliden-androst-4-en-3-one compound

Supplementary data for article: Filipović, N. R.; Borna, M.; Klisurić, O.; Pregelj, M.; Jagodić, M.; Anđelković, K. K.; Todorović, T. Synthesis, Characterization, and Thermal Behavior of Cu(II) and Zn(II) Complexes with (E)-2-[N-(1-Pyridin-2-Yl-Ethylidene)Hydrazino]Acetic Acid (AphaOH). Crystal Structure of [Zn-2(AphaO)(2)Cl-2]. Journal of Coordination Chemistry 2013, 66 (9), 1549–1560. https://doi.org/10.1080/00958972.2013.786052

Supplementary material for: [https://doi.org/10.1080/00958972.2013.786052]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1639