Macro- and microelements in soil profile of the moss-covered area in James Ross Island, Antarctica

The study of Antarctic ecosystem provides a valuable insight into the nature development on the Earth. Biocenosis formation and colonization of land by organisms are noticeable especially in newly-deglaciated areas. In this research, soil profile development in the coastal zone of James Ross Island was investigated. The main objective was the characterisation of soil horizons. The contents of As, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Ni, P, Se and Zn were measured using ICP-MS technique. Soil parameters like organic carbon content, pH and content ofsub-63 μm fraction were also determined. Based on the results obtained, the mineral-depleted and mineral‑enriched layers in the soil profile were distinguished. With increasing depth, the shallow soil profile consisted mainly of weathered regolith. Apparently, the basic processes which are prerequisite for the development of soil ecosystem in the studied area were confirmed

Mitochondrial diseases and ATPase defects of nuclear origin

AbstractDysfunctions of the F1Fo-ATPase complex cause severe mitochondrial diseases affecting primarily the paediatric population. While in the maternally inherited ATPase defects due to mtDNA mutations in the ATP6 gene the enzyme is structurally and functionally modified, in ATPase defects of nuclear origin mitochondria contain a decreased amount of otherwise normal enzyme. In this case biosynthesis of ATPase is down-regulated due to a block at the early stage of enzyme assembly—formation of the F1 catalytic part. The pathogenetic mechanism implicates dysfunction of Atp12 or other F1-specific assembly factors. For cellular energetics, however, the negative consequences may be quite similar irrespective of whether the ATPase dysfunction is of mitochondrial or nuclear origin

Experimental study and modeling of periodic bands in hydrated siliceous gels

Periodic structures can be seen practically everywhere in the world. In order to understand them deeply it is crucial to find a model, which can describe these structures to show their genesis and to predict their behavior while changing various input parameters. This paper deals with the experimental study on Liesegang ring formation made of copper chromate ions with copper sulphate used as an outer electrolyte and potassium chromate as an inner electrolyte. An aqueous solution of sodium silicate has been used as gel medium. The experiments were carried out in beakers as testing samples to find suitable sample weights of electrolyte compounds, then glass columns were used. The reaction process was periodically measured and photographed. Few few hours aft er start of the experiment, the first ring of precipitated copper chromate appeared. In the end, when all ions were consumed, the column was cut through, and the ion concentration was estimated by atomic absorption spectrophotometry and calculated theoretically using equation based on first and second Fick´s law of diffusion. The final calculation of diffusion coefficient was determined by least squares of deviations between measured and theoretical values of concentrations depending on the parameters D and C2 which gave us real values of diffusion coefficients and concentrations of ions in our system.Periodic structures can be seen practically everywhere in the world. In order to understand them deeply it is crucial to find a model, which can describe these structures to show their genesis and to predict their behavior while changing various input parameters. This paper deals with the experimental study on Liesegang ring formation made of copper chromate ions with copper sulphate used as an outer electrolyte and potassium chromate as an inner electrolyte. An aqueous solution of sodium silicate has been used as gel medium. The experiments were carried out in beakers as testing samples to find suitable sample weights of electrolyte compounds, then glass columns were used. The reaction process was periodically measured and photographed. Few few hours aft er start of the experiment, the first ring of precipitated copper chromate appeared. In the end, when all ions were consumed, the column was cut through, and the ion concentration was estimated by atomic absorption spectrophotometry and calculated theoretically using equation based on first and second Fick´s law of diffusion. The final calculation of diffusion coefficient was determined by least squares of deviations between measured and theoretical values of concentrations depending on the parameters D and C2 which gave us real values of diffusion coefficients and concentrations of ions in our system

EXPERIMENTÁLNÍ STUDIUM VZNIKU OSCILAČNÍCH VZORŮ REAKČNĚ-DIFUZNÍM MECHANISMEM

Banded structures are common in geological objects such as minerals and rocks. This paper is focused on a study of inner dynamics of the systems in which these structures can occur. There was performed an experiment to simulate banded structure formed in gel matrix. Mechanisms of regular pattern formation are discussed. The results of the experiment support the concept of selforganisation at formation of banded patterns. Any periodic changes in exterior are not necessary; this kind of pattern is formed by a reactiondiffusion process with feedback in nonlinear mechanism. Aim of this study was to improve method for recognition of nonlinear dynamics in natural geological objects and to bring laboratory experiments closer to real processes

Conditions of urinary stones formation

Urinary stones are generally products of pathological crystallization in the urinary tract. Their formation is influenced by many factors, such as genetic predisposition, age, stress, working environment or climate. They consist mainly of calcium oxalates and calcium phosphates. Formation of urinal stones was studied experimentally in laboratory. Solutions supersaturated with respect to the calcium oxalates and calcium phosphates were prepared by mixing stock solutions containing appropriate components (calcium, phosphate and oxalate ions). To simulate the conditions of urinary stones formation in real human urine the pH value of the solutions was adjusted with HCl and NaOH in the rage of 4.0 to 8.5 (pH range of normal human urine). After precipitation of solids, the solutions were sampled and analysed. Thermodynamic models were created to predict the theoretical conditions of urinary calculi formation. The results indicate that pH of solutions directly affects the aqueous speciation and, consequently, the formation of stones in the urinary tract. The comparison of results with human urine composition showed that urine of healthy human can contain higher amount of dissolved phosphates, oxalates or calcium substances than amount necessary for stones formation, but it may not lead to creation of urinary stones.Urinary stones are generally products of pathological crystallization in the urinary tract. Their formation is influenced by many factors, such as genetic predisposition, age, stress, working environment or climate. They consist mainly of calcium oxalates and calcium phosphates. Formation of urinal stones was studied experimentally in laboratory. Solutions supersaturated with respect to the calcium oxalates and calcium phosphates were prepared by mixing stock solutions containing appropriate components (calcium, phosphate and oxalate ions). To simulate the conditions of urinary stones formation in real human urine the pH value of the solutions was adjusted with HCl and NaOH in the rage of 4.0 to 8.5 (pH range of normal human urine). After precipitation of solids, the solutions were sampled and analysed. Thermodynamic models were created to predict the theoretical conditions of urinary calculi formation. The results indicate that pH of solutions directly affects the aqueous speciation and, consequently, the formation of stones in the urinary tract. The comparison of results with human urine composition showed that urine of healthy human can contain higher amount of dissolved phosphates, oxalates or calcium substances than amount necessary for stones formation, but it may not lead to creation of urinary stones

TRANSFORMACE BENTONITU V PODMÍNKÁCH ÚLOŽIŠTĚ RADIOAKTIVNÍHO ODPADU: GEOCHEMICKÝ MODEL

Geochemical modeling is (1) one of the ways how to asses bentonite stability and (2) an effective method to define key processes of a bentonite transformation. A simulation of bentonite transformation was performed for various physical and chemical conditions. The influence of pore water and mineral composition was theoretically studied. The modeling has shown that the most important factor which influences stability of bentonite is initial water composition and the presence of accessory minerals such as pyrite and calcite. The type of montmorillonite that forms the main part of bentonite did not play a key role in the bentonite transformation. Initial mixture of Na-, K-, Ca-, montmorillonites was transformed mainly into Mg- and Ca-montmorillonites. Totally 3 to 9 wt. % of initial bentonite was transformed to the secondary minerals

MIGRACE RADIONUKLIDU 226Ra V SEDIMENTECH RYCHVALDSKÉ STRUŽKY

Large amounts of mining waters are discharged into waterstreams in the region of Ostrava-Karviná Mining District. This paper deals with discharged mine water from the Žofie watershaft , which is located in Petrvald basin in Czech part of Upper Silesian coal basin. Mine water may affect surface watercourses, especially their sediments, which may have increased activity of radium 226Ra. The aim of this work was to evaluate geochemical evolution of the Rychvald creek with regard to the mobility of radium 226Ra and estimate the degree of influence. From the results, it is evident that the mine waters significantly affect the composition of Rychvald creek. Increased equivalent dose was measured only up to the wastewater treatment plant, which probably considerably diluted the water, consequently diminishing migration abilities of radium. From the result of physicochemical parameters it is evident that discharged mine water from the Žofie watershaft affects mainly conductivity, due to high mineralization of discharged mine water. Increased doses of the gamma radiation equivalent, which are related to the increased mass activity of radium 226Ra, were found in the sediment of the first 1 200 m of the Rychvaldské creek. However the determined increased activities of radium 226Ra do not represent neither substantial risk for human health nor important risk for the environment

Biotit a amfibol z ultradraselných hornin jihlavského plutonu – produkty sekundární hydratace pyroxenu

Syenites from the Jihlava pluton contain a broad spectrum of ferromagnesian minerals. Clinopyroxene (Cpx), Orthopyroxene (Opx), Biotite (Bt) Cummingtonite (Cum) and Actinolite (Act). Clino- and orthopyroxenes exhibit structures eg. zoning, admixtures typical for magmatic phases. Cummigtonite is partly product of hypersthene hydration, whereas actinolite originated on the expense of augite. Biotite grows at the contact between hypersthene and K-feldspar via reaction 3 Opx + Kfs = Bt + 3 Qtz. Because of hypersthene contains common admixtures of Cpx and K-feldspar contains myrmekites of andesine composition, therefore small amount of actinolitic hornblende originated during this reaction in addition. Much larger amount of actinolite, together with plagioclase was produced during the reaction between augite and K-feldspar – apart from prevailing biotite and quartz. Observed reactions indicate that the magma was dry and intrudes probably in the lower crust conditions, and was partly hydrated and reequilibrated during subsequent rapid exhumation