In this paper, facile synthesis of water soluble curcumin nanocrystals is reported. Solvent exchange method was applied to synthesize curcumin nanocrystals. Different techniques were used to characterize the structural and photophysical properties of curcumin nanocrystals. We found that nanocurcumin prepared by this method had good chemical and physical stability, could be stored in the powder form at room temperature, and was freely dispersible in water. It was established that the size of curcumin nanocrystals was varied in the range of 20-500 nm. Fourier transform infrared spectroscopy and UV-Vis analyses showed the presence of tetrahydrofuran inside the curcumin nanocrystals. Also, it was found that nanocurcumin emitted photoluminescencewith yellow-green colour. [Projekat Ministarstva nauke Republike Srbije, br. 172003]

Heteropoly acids (HPAs) found wide applications, such as in catalysis, energy conversion and storage, analytical chemistry, clinical medicine, materials science and others, but because of their low surface area and high solubility in water their use is limited. One of the possible ways to overcome these obstacles is to use height specific surface area support for HPAs, such as carbon nanomaterials. Raman spectroscopy was applied for studying study interaction between HPAs and highly ordered pyrolytic graphite (HOPG) as a model of a support. HOPG was exposed to two different HPAs: 12-tungstophosphoric acid and 12-molybodphosphoric acid, at different concentrations. It was noticed that 12-molybodphosphoric acid has stronger effects on HOPG structure causing a weak doping and increase of structural disorder. It is supposed that HOPG interacts with especially external oxygen atoms of 12-molybodphosphoric acid. Atomic force microscopy showed that surface roughness of HOPG treated with 12-molybodphosphoric acid increases with increase of acid concentration, while in the case of HOPG exposed to 12-tungstophosphoric acid the surface roughness is not concentration dependent. The growth trend in measured surface roughness (RMS) is in the agreement with the changes in the intensity ratio ID/IG obtained from Raman spectra of HOPG samples treated with 12-molybdophosphoric acid. [Projekat Ministarstva nauke Republike Srbije, br. 172003 i br. 172043]

Artefacts produced or treated at high temperatures provide information about manufacturing techniques. Well preserved ceramic objects are therefore excellent chronological markers as well as general markers of society development. In order to determine provenance of pottery fragments, archaeologists classify samples according to their physical characteristics, decoration and aesthetic style. However, a more objective multidisciplinary approach, based on undoubted results, is necessary to complete this study. In this work we have investigated 27 samples of medieval ceramics from excavation site Novo Brdo, using X-ray fluorescence (XRF), FTIR spectroscopy and X-ray powder diffraction (XRPD). Novo Brdo was large and rich mining and trading center of Serbia in XIV and XV century. A large number of ceramic samples found during the systematic excavation of this archaeological site allow good choice of samples for both destructive and nondestructive analysis. Combining results obtained by different experimental techniques, i.e. by FT-IR spectroscopy, after deconvolution of the spectra, and XRPD analysis, we have determined mineralogical composition and technology of production of investigated pottery. Estimated temperature of firing ranged from 800 to 900 °C, which is in agreement with the presence of high-temperature minerals like gehlenite and anorthite. Firing was preformed in the oxidation atmosphere since hematite, which is formed only in oxidation atmosphere, is detected in all investigated samples. Cross sections showed presence of defects and inhomogeneity of investigated ceramic, which indicates fast and incomplete firing procedure. All these findings indicate that investigated pottery was produced in the domestic workshops. The obtained results will be used to build up the National database for medieval ceramics as well as the database for the Balkan region

The antitumour action of three polyoxometallate compounds of Keggin's type: 12-molibdophosphoric acid (MoPA), 12-tungstophosphoric acid (WPA) and Mg salt of WPA (MgHWPA) was studied in vitro. For human cervix carcinoma (HeLa) cells survival, as well as for nonstimulated and stimulated peripheral blood mononuclear cells (PBMC), MTT test was applied and IC50 values of POMs were determinated. Index selectivity for WPA and MgHWPA are 1.9 and 1.8, calculated for nonstimulated, as well as 2.5 and 2.0, calculated for stimulated PBMS. Combination of studied POMs do not contribute to their lower IC50 values. Apoptosis detection implies mild cytotoxic effect of WPA and more cytostatical effect of MgHWPA. Combination of each of the studied POMs with caffeine decreases HeLa survival in dose dependent way. None of the studied POMs in the used concentrations (up to 100 mmol/L) damages blood cells and/or decreases their number.

A modified spectrophotometric method using the bismuth phosphomolybdate complex for the determination of phosphorus in coal and coal ash is suggested. Bismuth together with phosphate and molybdate forms a very stable complex in acid medium which turns blue ("molibdenum blue") by reduction with ascorbic acid. The apparent molar absorptivity of PBiMo is 1.66x104 dm3 mol-1cm-1 at 720 nm and 2.10x104 dm3 mol-1cm-1 at 670 nm isobutyl methyl ketone (MIBK). Interference caused by the ions present are within the tolerance limits (?2 %). Beer?s law is obeyed in the for concentration range to 0.6 ?g/mL (aqueous solution) and to 1.2 ?g/mL P (MIBK). The sensitivity of the proposed method is 0.0078 ?g/mL (aqueous solution) and 0.0066 ?g/mL (MIBK).