Priprema i karakterizacija poli(Uretan-siloksan)/titan-dioksid nanokompozita

This work is focused on preparation of poly(urethane-siloxane)/titanium-dioxide nanocomposites (PUSNs) with enhanced features. PUSNs were prepared by the in situ polymerization reaction using titanium-dioxide as a nano-filler in different amounts (1, 2, 3 and 5 wt.%) with respect to the poly(urethane-siloxane) (PUS) matrix. PUS copolymer was based on α,ω-dihy-droxy-ethoxypropyl-poly(dimethylsiloxane), 4,4’-methylenediphenyldiisocyanate and 1,4-bu-tanediole. In order to investigate the influence of TiO 2 content on the structure, UV resistance, thermal properties, hydrophobicity and morphology of the prepared PUSNs, FTIR spectroscopy, UV-Vis diffuse-reflectance spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, surface free energy (SFE) analysis, water absorption, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed. The PUSNs showed excellent UV resistance, high hydrophobicity, low surface free energy and also higher thermal stability and rougher surface and cross-section relief structure as compared to the pure PUS copolymer. Based on the obtained results it can be concluded that prepared PUSNs could be potentially used as protective coatings. © 2019, Association of Chemists and Chemical Engineers of Serbia. All rights reserved

Assessment of genetic diversity among alfalfa (Medicago sativa L.) genotypes by morphometry, seed storage proteins and RAPD analysis

Alfalfa is the world's widest grown forage crop with novel applications in the production of commercial proteins and biomass for biofuel. These alternative uses of alfalfa require new cultivars and breeding processes adjusted to specific production systems and demands. An estimate of the genetic diversity and differentiation between genotypes of breeding germplasm is of key importance for its improvement. Traditionally, it is has been achieved through morphological analyses, although novel methods of molecular marker analysis offer faster and more reliable tools. The objective of this study was to determine genetic variability of ten populations of alfalfa as a part of a collection at the Institute for Forage Crops, Krusevac, Serbia and to reveal relationships among genotypes through UPGMA(1) cluster analysis. Data obtained through three different methods were compared and the correlation among them was estimated. It has been found that clustering of examined genotypes based on analysis of morphology traits has the best fit with geographical origin of genotypes. Methods using molecular markers, as seed storage proteins or RAPDs,(2) provide a rapid way to discriminate between genotypes and have strong mutual correlation. Estimating the genetic distance through molecular marker analysis showed a poor fit of distance in relation to morphological analyses. (C) 2012 Elsevier By. All rights reserved.Ministry of Education and Science, Republic of Serbia [TR31057, 173024

Assessment of genetic diversity among alfalfa (Medicago sativa L.) genotypes by morphometry, seed storage proteins and RAPD analysis

Alfalfa is the world's widest grown forage crop with novel applications in the production of commercial proteins and biomass for biofuel. These alternative uses of alfalfa require new cultivars and breeding processes adjusted to specific production systems and demands. An estimate of the genetic diversity and differentiation between genotypes of breeding germplasm is of key importance for its improvement. Traditionally, it is has been achieved through morphological analyses, although novel methods of molecular marker analysis offer faster and more reliable tools. The objective of this study was to determine genetic variability of ten populations of alfalfa as a part of a collection at the Institute for Forage Crops, Krusevac, Serbia and to reveal relationships among genotypes through UPGMA(1) cluster analysis. Data obtained through three different methods were compared and the correlation among them was estimated. It has been found that clustering of examined genotypes based on analysis of morphology traits has the best fit with geographical origin of genotypes. Methods using molecular markers, as seed storage proteins or RAPDs,(2) provide a rapid way to discriminate between genotypes and have strong mutual correlation. Estimating the genetic distance through molecular marker analysis showed a poor fit of distance in relation to morphological analyses. (C) 2012 Elsevier By. All rights reserved.Ministry of Education and Science, Republic of Serbia [TR31057, 173024

JSCS–3884 Original scientific paper

Changes in the infrared attenuated total reflectance (ATR) spectra of lignins from alfalfa stem with growth and developmen

Analysis of the post-vitellogenic oocytes of three species of Danubian Acipenseridae

Post-vitellogenic oocytes of beluga (Huso huso Linnaeus, 1758), Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1883) and sterlet (Acipenser ruthenus Linnaeus, 1758), sampled downstream of the "Iron Gate II" dam on the Danube River, were characterised according to diameter, dry mass, water and protein contents. All oocytes examined were ovoid in shape with the major diameter being measured in the animal-vegetal axis. The beluga oocytes were the largest, with major and minor diameters of 4.18 +/- 0.13 and 3.61 +/- 0.14 mm, respectively. The oocytes of the Russian sturgeon were the next largest, with major and minor diameters of 3.69 +/- 0.16 and 3.36 +/- 0.15 mm, respectively, while those of the sterlet were the smallest, with major and minor diameters of 2.40 +/- 0.10 and 2.14 +/- 0.07 mm, respectively. Values for oocyte wet and dry mass (mg/ind) ranged from 25.9-32.1 for wet mass and 12.2-15.5 for dry mass of the beluga oocytes, 18.9 +/- 1.4, and 9.01 +/- 0.12 for wet and dry mass of the Russian sturgeon oocytes, to 6.5 +/- 0.3 and 3.07 +/- 0.14 of the sterlet oocytes. The water content of the oocytes of all three sturgeons was very similar (51-53 % of wet mass). The protein content (% of dry mass) was highly conservative among the species at 53.0 +/- 2.0, 55.9 +/- 3.8 and 50.0 +/- 1.2 for the oocytes of beluga, Russian sturgeon and sterlet, respectively.nul

Analysis of the post-vitellogenic oocytes of three species of Danubian Acipenseridae

Post-vitellogenic oocytes of beluga (Huso huso Linnaeus, 1758), Russian sturgeon (Acipenser gueldenstaedtii Brandt, 1883) and sterlet (Acipenser ruthenus Linnaeus, 1758), sampled downstream of the "Iron Gate II" dam on the Danube River, were characterised according to diameter, dry mass, water and protein contents. All oocytes examined were ovoid in shape with the major diameter being measured in the animal-vegetal axis. The beluga oocytes were the largest, with major and minor diameters of 4.18 +/- 0.13 and 3.61 +/- 0.14 mm, respectively. The oocytes of the Russian sturgeon were the next largest, with major and minor diameters of 3.69 +/- 0.16 and 3.36 +/- 0.15 mm, respectively, while those of the sterlet were the smallest, with major and minor diameters of 2.40 +/- 0.10 and 2.14 +/- 0.07 mm, respectively. Values for oocyte wet and dry mass (mg/ind) ranged from 25.9-32.1 for wet mass and 12.2-15.5 for dry mass of the beluga oocytes, 18.9 +/- 1.4, and 9.01 +/- 0.12 for wet and dry mass of the Russian sturgeon oocytes, to 6.5 +/- 0.3 and 3.07 +/- 0.14 of the sterlet oocytes. The water content of the oocytes of all three sturgeons was very similar (51-53 % of wet mass). The protein content (% of dry mass) was highly conservative among the species at 53.0 +/- 2.0, 55.9 +/- 3.8 and 50.0 +/- 1.2 for the oocytes of beluga, Russian sturgeon and sterlet, respectively.nul

Removal of alprazolam from aqueous solutions by heterogeneous photocatalysis: Influencing factors, intermediates, and products

Efficiency of heterogeneous photocatalytic degradation of aiprazolam was investigated. The structural and morphological properties of ZnO were investigated in detail. It was found that ZnO has wurtzite structure with crystallite size about 41 nm, specific surface area about 6.5 m(2)/g, and intraparticle system of pores (maximum pore width about 160 nm). The efficiency of aiprazolam photocatalytic degradation was examined as a function of the type of irradiation (UVA, visible, and simulated solar irradiation) and photocatalyst (ZnO, TiO2 Degussa P25), photocatalyst loading, pH, and the presence of hydroxyl radical, and positive hole scavengers. By examining the effect of types of irradiation and catalysts, it was found that the UVA/ZnO system is the most efficient for alprazolam removal. The optimum catalyst loading was 2.0 mg/mL for TiO2 Degussa P25, while in presence of ZnO degradation rate increases in whole investigated range. In the case of ZnO, the pH 7 was selected as an optimal condition, while in aqueous suspension of TiO2 Degussa P25, degradation rate increases in whole investigated pH range (3.4-8.8), but increasing is not as pronounced as in case of ZnO. Also, it was found that ZnO photocatalysis takes place only via hydroxyl radicals, while using TiO2 Degussa P25 positive holes play significant role, too. The results of total organic carbon and ionic chromatography analysis showed that after 60 min of irradiation using both catalysts aiprazolam was completely mineralized. Here, for the first time, reaction intermediates formed using both catalysts were studied in detail, whereby the main intermediates were hydroxyl derivates. ZnO showed high stability in photodegradation after three successive runs