Pyrite-induced hydroxyl radical formation and its effect on nucleic acids

BACKGROUND: Pyrite, the most abundant metal sulphide on Earth, is known to spontaneously form hydrogen peroxide when exposed to water. In this study the hypothesis that pyrite-induced hydrogen peroxide is transformed to hydroxyl radicals is tested. RESULTS: Using a combination of electron spin resonance (ESR) spin-trapping techniques and scavenging reactions involving nucleic acids, the formation of hydroxyl radicals in pyrite/aqueous suspensions is demonstrated. The addition of EDTA to pyrite slurries inhibits the hydrogen peroxide-to-hydroxyl radical conversion, but does not inhibit the formation of hydrogen peroxide. Given the stability of EDTA chelation with both ferrous and ferric iron, this suggests that the addition of the EDTA prevents the transformation by chelation of dissolved iron species. CONCLUSION: While the exact mechanism or mechanisms of the hydrogen peroxide-to-hydroxyl radical conversion cannot be resolved on the basis of the experiments reported in this study, it is clear that the pyrite surface promotes the reaction. The formation of hydroxyl radicals is significant because they react nearly instantaneously with most organic molecules. This suggests that the presence of pyrite in natural, engineered, or physiological aqueous systems may induce the transformation of a wide range of organic molecules. This finding has implications for the role pyrite may play in aquatic environments and raises the question whether inhalation of pyrite dust contributes to the development of lung diseases

Molecular cloning and sequencing of partial cDNA of tumor necrosis factor and p75 tumor necrosis factor receptor of Syrian golden hamster (Mesocricetus auratus) with the use of universal primers.

In this study we cloned and analysed partial cDNA of tumor necrosis factor (TNF) and p75 TNF-R receptor of Syrian golden hamster (Mesocricetus auratus). We obtained a 382-bp sequence of TNF and a 148-bp sequence coding for p75 TNF-R. The primers used for the cloning were designed on the basis of inter-species homology, thus presumably can be used for cloning and analysis of TNF and p75 TNF-R genes of other mammals

CFD methods as a modern tool in optimisation of hydrodynamic conditions in magma crystallizers

Selected parameters concerning the optimisation of hydrodynamics in magma crystallizers are discussed. At this stage, results of CFD (Computational Fluid Dynamics) simulations are shown, focused on the effect of the geometrical configuration of a crystallizer on energy dissipation rate, axial velocity field and general hydraulic efficiency. The influence of the shape of the apparatus' bottom, diameter of the stirrer, its location and presence of the draft tube on, respectively: (i) unit power input distribution, (ii) the average mixing power, and (iii) pumping capacity have been takeninto consideration. The results obtained from simulations have been compared with experiments and literature data

Molecular cloning and sequencing of partial cDNA of tumor necrosis factor and p75 tumor necrosis factor receptor of Syrian golden hamster (Mesocricetus auratus) with the use of universal primers.

In this study we cloned and analysed partial cDNA of tumor necrosis factor (TNF) and p75 TNF-R receptor of Syrian golden hamster (Mesocricetus auratus). We obtained a 382-bp sequence of TNF and a 148-bp sequence coding for p75 TNF-R. The primers used for the cloning were designed on the basis of inter-species homology, thus presumably can be used for cloning and analysis of TNF and p75 TNF-R genes of other mammals

Chart of technology solutions for coal gasification processes

W artykule przedstawiono porównanie najbardziej dojrzałych i perspektywicznych reaktorów, które mogą być wykorzystane do zgazowania węgla w polskich warunkach. Wybrano reaktory dyspersyjne: Shell, GE/Texaco, Prenflo, Siemens i E-Gas, reaktor fluidalny U-Gas oraz reaktor transportujący KBR Transport. Reaktory te reprezentują różne rozwiązania technologiczne. Technologie wykorzystujące te reaktory są szeroko stosowane na całym świecie i mogą być wykorzystane zarówno dla potrzeb sektora energetycznego, jak i chemii czy produkcji paliw. Dokonano również analizy różnych rozwiązań technologicznych procesów podziemnego zgazowania węgla oraz najważniejszych konfiguracji technologicznych oczyszczania gazu ze zgazowania, w zależności od jego zastosowania.This paper presents a comparison of the most advanced and prospective reactors which can be used for coal gasification in Poland. Entrained bed reactors Shell, GE / Texaco, Prenflo, Siemens and E-Gas fluidized bed reactor U-Gas and the transporting reactor KBR were taken into consideration. These reactors represent different technological solutions. Technologies using these reactors are widely used throughout the world and can be used both for energy, chemicals and fuels production. Various technological processes of underground coal gasification and the most important technological configuration of the gasification gas purification, depending on its application, were also examined