Solvent-Free Mechanochemical Synthesis and Characterization of Nickel Tellurides with Various Stoichiometries: NiTe, NiTe2 and Ni2Te3.

The paper reports the synthesis of nickel tellurides via a mechanochemical method from elemental precursors. NiTe, NiTe2, and Ni2Te3 were prepared by milling in stainless steel vials under nitrogen, using milling times from 1 h to 12 h. The products were characterized by powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), UV-VIS spectrometry, and thermal analysis (TGA and DSC). The products were obtained in the form of aggregates, several hundreds of nanometers in size, consisting of smaller nanosized crystallites. The magnetic measurements revealed a ferromagnetic behavior at room temperature. The band gap energies calculated using Tauc plots for NiTe, NiTe2, and Ni2Te3 were 3.59, 3.94, and 3.70 eV, respectively. The mechanochemical process has proved to be a simple and successful method for the preparation of binary nickel tellurides, avoiding the use of solvents, toxic precursors, and energy-consuming reaction conditions.

The Distribution of Minerals in Crucial Plant Parts of Various Elderberry (Sambucus spp.) Interspecific Hybrids.

In view of growing requirements of the food industry regarding elderberries (genus Sambucus), a need to increase their productivity and improve their chemical composition has emerged. With this purpose in mind, numerous elderberry interspecific hybrids have been created. In the present work, the content of minerals in their crucial plant parts was studied. It was also investigated whether superior genotypes regarding the mineral composition of berries and inflorescences could be predicted at early stages of plant development. The results showed that elderberry leaves contained the highest amounts of Ca, Mg, Mn, Zn, and Sr, while K and P were predominant in fruit stalks. Fe and Al prevailed in roots and Cu in bark. Although berries showed lower mineral content compared to other plant parts, their mineral content is not negligible and could be comparable to other commonly consumed berries. Genotypes with a favorable mineral content of inflorescences and berries could be predicted on the basis of known mineral composition of their shoots and leaves. The study also indicates that S. nigra genotypes and the majority of interspecific hybrids analyzed are suitable for further genetic breeding or cultivation.

Effects of integrated and organic pest management with copper and copper-free preparations on tomato (Lycopersicum esculentum Mill.) fruit yield, disease incidence and quality.

The present study investigates the effect of exclusion of copper preparations from spray programs for disease control in integrated and organic tomato production systems on disease incidence, yield and fruit vitamin C, α-tocopherol and carotenoids content for Monroe, Optima and Paki cultivars. Open field trials were conducted in a randomized block system with four repetitions over two years. Treatment for plant disease control comprised four spraying programs, two within each production system. Yields were significantly affected by cultivar, pest management system and their interaction. Copper-free integrated and organic spraying programs were almost as effective in disease control as standard treatments which included copper preparations. The spraying program significantly affected the contents of vitamin C, α-tocopherol, phytoene, and ß-carotene in fruits; however, the effect was cultivar related. The lycopene contents appeared to be unaffected by the spraying program or growing system.

Synthesis of nickel and cobalt sulfide nanoparticles using a low cost sonochemical method.

Nickel and cobalt sulfides are promising materials in different cutting-edge research areas like solar cells, supercapacitors, catalysts, and electrode materials. Nickel and cobalt sulfides with various stoichiometries have been synthesized sonochemically from Ni(CH3COO)2 ∙ 4H2O, Co(CH3COO)2 ∙ 2H2O and different sulfur precursors using a direct immersion ultrasonic probe. The products were characterized by X-ray powder diffraction, transmission electron microscopy (TEM) including EDX analysis, IR and UV-Vis spectroscopy and elemental analysis. Following products have been obtained: NiS, Ni3S4, CoS1.097 and Co9S8, with average crystallite sizes in the range 7-30 nm. Effects of different reaction conditions on the size, morphology and optical band-gap energy were evaluated. Optical band-gap energies in the range 3.3 eV-3.8 eV were observed for the obtained nanoparticles.

Variation of mineral composition in different parts of taro (Colocasia esculenta) corms.

Taro (Colocasia esculenta) is an important root crop in the humid tropics and a valuable source of essential mineral nutrients. In the presented study, we compared the mineral compositions of four main parts of taro corm: the upper, marginal, central and lower (basal) parts. The freeze-dried taro samples were analysed for eleven minerals (K, P, Mg, Ca, Zn, Fe, Mn, Cu, Cd, Pb and Cr). The upper part, which plays a critical role in vegetative propagation based on headsets, contained high levels of P, Mg, Zn, Fe, Mn, Cu and Cd. The central part, which is essential for human nutrition, was characterised by higher concentrations of K, P, Mg, Zn, Fe, Cu and Cd. Ca was concentrated in the lower and marginal parts. The effect of the genotype was significant for more than half of the analysed minerals (i.e., Mg, Ca, Zn, Fe, Mn).

Strawberries from integrated and organic production: mineral contents and antioxidant activity.

As the nutritional quality of food is becoming increasingly more important for consumers, significant attention needs to be devoted to agricultural practices and their influences on the nutrient contents in food. The presented investigation studied the mineral contents and antioxidant activities in the fruits of four organically-grown strawberry cultivars 'St. Pierre', 'Elsanta', 'Sugar Lia' and 'Thuchampion' when compared to those of integrated-grown plants. The strawberries were digested and analyzed for K, Mg, Fe, Zn, Cu, and Mn using an atomic absorption spectrometer, whilst P was analyzed using a vanadate-molybdate method. In addition, antioxidant activity was estimated by using the ABTS assay. The results showed that the mineral contents and antioxidant activities in strawberries depends on the cultivar, and its production system. Organically-grown fruits showed higher antioxidant activities and Cu content than the integrated fruits, whilst the integrated fruits were superior in their contents of P, K, Mg, Fe and Mn. All the cultivars showed similar Zn content, probably reflecting the fact that the Zn content in strawberries does not depend on the cultivar.

Determination of jasmonic acid in Lemna minor (L.) by liquid chromatography with fluorescence detection.

A new method is described for the determination of endogenous jasmonic acid (JA) in Lemna minor plant extracts using liquid chromatography (LC) with fluorescence detection. Plant tissues were extracted and derivatised using 9-anthryldiazomethane (ADAM reagent) prepared in situ. Accuracy and precision were improved by using the internal standard dihydrojasmonic acid (dh-JA) for the correction of JA losses during sample preparation steps. Liquid chromatography-mass spectrometry (LC/MS) analysis of ADAM derivatives of JA and dh-JA confirmed that a single molecule of JA and dh-JA was coupled with one molecule of reagent. Derivatives of JA and dh-JA were separated with gradient elution on a C18 reversed-phase column using acetonitrile/water as a mobile phase and detected by a fluorescence detector at excitation and emission wavelengths of 254 and 412 nm, respectively. The detection limits of JA and dh-JA were 2.9 ng mL(-1) and 3.7 ng mL(-1) per 50-microL injection. The method is reproducible and selective and yields single peaks for each compound regardless of isomer. The specificity and accuracy of the proposed LC/FD method was confirmed by liquid chromatography-TurboIon Spray tandem mass spectrometric (LC/MS/MS) analysis of free JA in Lemna minor samples under multiple reaction monitoring conditions.

The application of ETAAS to the determination of Cr, Pb and Cd in samples taken during different stages of the winemaking process.

Chromium, cadmium and lead were determined in different fractions of the winemaking process such as in grape, pressed pomace, must deposit, deposit of lees, must and wine. Grape, pressed pomace, must deposit and deposit of lees were digested by a high-pressure microwave-assisted digestion system with a mixture of nitric acid and hydrogen peroxide, while for must and wine no special treatment was required. The temperature programs of the graphite furnace were optimised and different matrix modifiers were applied: Mg(NO3)2, NaVO3 for Cr and NH4H2PO4, Pd(NO3)2 for Pb and Cd determinations. Mg(NO3)2 and NaVO3 thermally stabilized Cr and enabled the increase of pyrolysis temperatures up to 1500 degrees C. NH4H2PO4 and Pd(NO3)2 are suitable modifiers for Pb and allowed pyrolysis temperatures up to 800 degrees C in grape, pressed pomace and wine samples, 1100 degrees C in must samples and 1200 degrees C in deposit of lees. The non-specific background absorption of NH4H2PO4 was 1.5-2 orders of magnitude higher than that of the Pd(NO3)2.