Influence green sand system by core sand additions

Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?”This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition). Ratio of active betonite by Methylene blue test was also determined

Arrangements of human telomere DNA quadruplex in physiologically relevant K+ solutions

The arrangement of the human telomeric quadruplex in physiologically relevant conditions has not yet been unambiguously determined. Our spectroscopic results suggest that the core quadruplex sequence G3(TTAG3)3 forms an antiparallel quadruplex of the same basket type in solution containing either K+ or Na+ ions. Analogous sequences extended by flanking nucleotides form a mixture of the antiparallel and hybrid (3 + 1) quadruplexes in K+-containing solutions. We, however, show that long telomeric DNA behaves in the same way as the basic G3(TTAG3)3 motif. Both G3(TTAG3)3 and long telomeric DNA are also able to adopt the (3 + 1) quadruplex structure: Molecular crowding conditions, simulated here by ethanol, induced a slow transition of the K+-stabilized quadruplex into the hybrid quadruplex structure and then into a parallel quadruplex arrangement at increased temperatures. Most importantly, we demonstrate that the same transitions can be induced even in aqueous, K+-containing solution by increasing the DNA concentration. This is why distinct quadruplex structures were detected for AG3(TTAG3)3 by X-ray, nuclear magnetic resonance and circular dichrosim spectroscopy: Depending on DNA concentration, the human telomeric DNA can adopt the antiparallel quadruplex, the (3 + 1) structure, or the parallel quadruplex in physiologically relevant concentrations of K+ ions

Selected nutritional values of field cricket (<em>Gryllus assimilis</em>) and its possible use as a human food

518-524The nutritional values of the field cricket (Gryllus assimilis (Fabricius, 1775)) were analysed for dry matter using infrared scales, crude protein using Kjeldahl method, fat by Soxhlet method and fatty acid composition using GC-MS. The average dry matter content of analysed insect was 22.6 %, content of crude protein was 55.6 %, fat content was 11.8 %. The analysis of the fatty acid profile shows that the most abundant fatty acids were C18:2, C16:0 and C18:1 and the atherogenic index was 0.55. Microbial analyses were also part of the research, with evaluation of the total content of bacteria (3.3.106 CFU g-1), coli form bacteria (3.5.104 CFU g-1) and lactic acid bacteria (5.8.106 CFU g‑1) and of yeasts and moulds (4.4.105 CFU g‑1). For the high content of lipids and proteins edible insects could be a good alternative future source of crude protein and fat. EFSA also deals with obtaining sufficient data about the nutritional value and safety of consuming edible insects