Hematite Core Nanoparticles with Carbon Shell: Potential for Environmentally Friendly Production from Iron Mining Sludge

Hematite nanoparticles with amorphous, yet relatively uniform carbon shell, were produced based exclusively on the waste sludge from the iron mine as the raw material. The procedure for acid digestion-based purification of the sludge with the full recovery of acid vapors and the remaining non-toxic rubble is described. Synthesis of the hematite nanoparticles was performed by the arrested precipitation method with cationic surfactant. The particles were thoroughly characterized and the potential of their economical production for the battery industry is indicated.     

Ternary Au-Ga-Sb system: calculation of thermodynamic properties using general solution model

The calculated results of thermodynamic properties in ternary Au-Ga-Sb system by general solution model were presented in this paper.The calculations were carried out in nine cross sections from all three corners in the temperature range of 973–1,573 K,and integral molar excess Gibbs energies,partial molar Gibbs energies,activity coefficients and activities for all components are obtained.The activity of gold and gallium shows negative deviation from Rault's law for all investigated sections,while antimony activity is close to the line of ideal conditions and even coincides with the line for high content of antimony in the alloy.Data obtained by calculation were compared with those found in literature.It is concluded that compared values show reasonable good agreement.     

Detection of GM soybean in food products by simultaneous employment of three pairs of PCR primers

Genetically modified soybean was explored in food samples, labeled as “non-GM” and unlabeled, using multiplex PCR and Real-time PCR techniques. In total 110 (2006) and 237 food samples (2007) containing soybean were analyzed. The 7% of the products were shown to consist of material derived from the Roundup Ready soybean in 2006 and 13% of the foods samples in 2007. The most of analyzed samples were correctly labeled, but ten of food products are demonstrated to contain material above the threshold levels for labeling of 0.9%. This is the first report of the validity of labels on imported food samples from different countries and uptake of GM food derived from soybean into the food chain in Serbia.     

Photodynamic Antimicrobial Cellulosic Material Through Covalent Linkage of Protoporphyrin IX onto Lyocell Fibers

Here, we report the preparation of porphyrin-functionalized Lyocell fibers according to an azide-alkyne click concept. First, azido-modified Lyocell fibers and alkynylated protoporphyrin building blocks were prepared through alkoxysilane chemistry and Steglich esterification, respectively. Lyocell fibers were pre-activated by swelling in organic solvents in order to increase the accessibility of hydroxyl groups in the subsequent silanization process. The azide-equipped cellulosic matrix reacted with the propargyl groups of the protoporphyrin IX derivative in a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC), by which protoporphyrin IX was introduced onto the surface of the Lyocell fibers. The modified building blocks and the final functionalized cellulosic materials were comprehensively characterized by FTIR, NMR, UV/Vis spectroscopy and elemental analysis. Photo-bactericidal activity of modified fibers against 2?gram-positive bacteria strains, including Staphylococcus aureus and Bacillus subtilis, were investigated and compared to those of unmodified and azido-modified Lyocell fibers. The results confirmed the photo-antibacterial activity of the synthesized fibers against both bacteria strains.     

Preparation of LiFePO4/C composites by co-precipitation in molten stearic acid

The olivine type LiFePO₄ is synthesized via a simple and inexpensive route by aqueous co-precipitation of an Fe(II) precursor material in molten stearic acid and subsequent heat treatment at different temperatures. Stearic acid serves as both chelating agent and carbonaceous material. The obtained composites with carbon are characterized by X-ray powder diffraction, field emission scanning electron microscopy, and Mössbauer spectroscopy. Electrochemical characteristics of the composites are evaluated by using galvanostatic charge/discharge tests. The powder obtained at 700 °C delivers discharge capacity of 160 mAh g⁻¹, quite near the theoretical value.     

In vitro antioxidant and antiproliferative activity of three rosemary (Rosmarinus officinalis L.) extract formulations

Antioxidant and antiproliferative activities of three rosemary extract formulations (VivOX 20, VivOX 40 and Inolens 50) with different contents of carnosic acid, carnosol and methylcarnosol were tested in vitro. Electron spin resonance measurements revealed that Inolens 50 extract that contained highest amount of carnosic acid was the most potent scavenger of hydroxyl (concentration of extract where 50% of its maximal scavenging activity is observed, that is, EC₅₀, 109.54 μg mL^?1), superoxide anion (EC₅₀ = 7.94 μg mL^?1) and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) (EC₅₀ = 27.4 μg mL^?1)‐free radicals. Comparison of the radar charts of standard antioxidants and rosemary extracts showed similarity between antioxidant characteristics of Inolens 50 and chlorogenic and caffeic acids. Tested rosemary extracts exhibited significant (P ≤ 0.01) antiproliferative effect in cervix epitheloid carcinoma (HeLa), breast adenocarcinoma (MCF7) and colon adenocarcinoma (HT‐29) cell lines. In both MCF7 and HeLa cell lines, the extracts yielded very low IC₅₀ values (concentration of extract needed to inhibit cell growth by 50%), the most pronounced being for Inolens 50 in MCF7 (IC₅₀ = 9.95 μg mL^?1) and VivOX 20 in HeLa cell line (IC₅₀ = 10.02 μg mL^?1). The obtained results may provide support for the use of tested rosemary extracts as nutraceuticals and phytopharmaceuticals.     

Characterization of the Ni-Mo catalyst formed in situ during hydrogen generation from alkaline water electrolysis

Objective of this work was to investigate the electrocatalytic efficiency using quasi-potentiostatic, galvanostatic and impedance spectroscopy techniques of the Ni-Mo catalysts obtained by in situ electrodeposition in an alkaline, 6 M KOH, electrolyser. In accordance to our previous studies, synergetic effect is observed, with its maximum at industrial conditions (high temperature and current density). The Tafel slopes are around 120 mV and exchange current densities are close to 10⁻² mA cm⁻² (three orders of magnitude higher compared to the bulk Ni). Moreover, formed deposit possess high stability during prolonged electrolysis. Results are presented to show the Tafel slopes, the exchange current densities, the apparent energy of activation, the apparent electrochemical surface and the stability of in situ formed Ni-Mo catalyst. Results suggest to significant catalytic performance not only from the increase of the real surface area of electrodes, but also from the true catalytic effect.     

Effect of low‐trans margarine on physicochemical and sensory properties of puff pastry1

The influence of the low‐trans (<1% of total fatty acids) puff pastry margarine and the rest period between laminating on dough physical characteristics and puff pastry quality was investigated. Experiment was planed according to factorial plan 3² with independent variables: quantity of puff pastry margarine (35–55% based on flour, variation interval 10) and rest period (15–45 min, variation interval 15). The experiment involved two margarine samples (MLT1 and MLT2) of similar fat phase composition, but whose physical properties were, statistically speaking, significantly different. The results show that the pastry containing 35% of margarine MLT1 and allowing the rest period of 30 and 45 min has a lift of above 4.0, it is of minimal firmness and has a high specific volume (3.5 cm³ g^?1). Having used puff pastry margarine MLT2, the highest quality of dough and pastry was achieved in the sample containing 55% of margarine and with the maximum rest period of 45 min. The sample mentioned showed an excellent lift of 5.3 and had a specific volume of 4.0 cm³ g^?1, but it as well exhibited the maximal firmness of pastry. The application of puff pastry margarine MLT1 can result in a satisfactory quality of pastry, but it can also cause a reduction in the fat content by 7.5% and in the content of trans fatty acids by two times, while the energy value is reduced by 12% when compared with the pastry containing puff pastry margarine MLT2.     

DFT study of platinum and palladium overlayers on tungsten carbide: Structure and electrocatalytic activity toward hydrogen oxidation/evolution reaction

Platinum and palladium overlayers on W- and C-terminated WC(0001) surface, at coverage ranging from 0.25 ML to 2 ML, have been studied using DFT approach. Strong adhesion of metal monolayers to the WC support, accompanied by a modification of electronic structure, was evidenced. Calculated values of hydrogen binding energy on studied metal overlayers were correlated to available experimentally determined values of exchange current densities of hydrogen oxidation/evolution reaction (HOR/HER), resulting with the volcano curve with both explanatory and predictive power. None of the investigated metal/WC surfaces were found to exceed the Pt(111) surface in terms of catalytic activity toward HER/HOR. The obtained results indicate that WC may efficiently replace the precious metal support in the Pt (Pd) core–shell electrocatalyst for HER/HOR, but no synergism arising due to electronic effects of WC support was evidenced.