10 research outputs found

    Stability and Serviceability of Tailing Heaps With Visco-Plastic Materials

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    The tailings of potash mining are piled up in huge heaps with heights of up to more than 200 m and a ground area of often more than a square km. The material behaviour of the salt is strongly visco-plastic, so that the slopes of the heaps are moving constantly at slow rates. As the strength of the salt is rate-dependent, structural analysis of the slope stability has to consider the deformations and deformation rates and the interaction of subsoil and slope. Due to the complex material behaviour the structural analysis is accompanied by an extensive measuring programme within the Observational Method. The paper focuses on two slopes of tailing heaps, where huge deformations partly at accelerating deformation rates occurred, due to natural respectively man-made slip-surfaces in the subsoil. The deformation rates were critically high and deformations induced serviceability problems to infrastructure at the base of the slope. It is shown, how the restoration of the endangered slopes and infrastructure was established. The concept of restoration is based on both intensive measuring and numerical simulations

    Design and Construction of Deep Foundation Systems and Retaining Structures in Urban Areas in Difficult Soil and Groundwater Conditions

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    Economic and environment-friendly design focuses on a reduction of construction material used, construction time spent and energy consumed within the buildings construction and service time. Regarding deep foundation systems and retaining structures for excavations this paper highlights the important role of enhanced geotechnical design and independent quality assurance by means of the 4-eye- principle

    Natural and Engineered Hydroxyectoine Production Based on the Pseudomonas stutzeri ectABCD-ask Gene Cluster▿ †

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    We report on the presence of a functional hydroxyectoine biosynthesis gene cluster, ectABCD-ask, in Pseudomonas stutzeri DSM5190T and evaluate the suitability of P. stutzeri DSM5190T for hydroxyectoine production. Furthermore, we present information on heterologous de novo production of the compatible solute hydroxyectoine in Escherichia coli. In this host, the P. stutzeri gene cluster remained under the control of its salt-induced native promoters. We also noted the absence of trehalose when hydroxyectoine genes were expressed, as well as a remarkable inhibitory effect of externally applied betaine on hydroxyectoine synthesis. The specific heterologous production rate in E. coli under the conditions employed exceeded that of the natural producer Pseudomonas stutzeri and, for the first time, enabled effective hydroxyectoine production at low salinity (2%), with the added advantage of simple product processing due to the absence of other cosolutes

    Endurance training modulates the muscular transcriptome response to acute exercise

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    We hypothesized that in untrained individuals (n=6) a single bout of ergometer endurance exercise provokes a concerted response of muscle transcripts towards a slow-oxidative muscle phenotype over a 24-h period. We further hypothesized this response during recovery to be attenuated after six weeks of endurance training. We monitored the expression profile of 220 selected transcripts in muscle biopsies before as well as 1, 8, and 24 h after a 30-min near-maximal bout of exercise. The generalized gene response of untrained vastus lateralis muscle peaked after 8 h of recovery (P=0.001). It involved multiple transcripts of oxidative metabolism and glycolysis. Angiogenic and cell regulatory transcripts were transiently reduced after 1 h independent of the training state. In the trained state, the induction of most transcripts 8 h after exercise was less pronounced despite a moderately higher relative exercise intensity, partially because of increased steady-state mRNA concentration, and the level of metabolic and extracellular RNAs was reduced during recovery from exercise. Our data suggest that the general response of the transcriptome for regulatory and metabolic processes is different in the trained state. Thus, the response is specifically modified with repeated bouts of endurance exercise during which muscle adjustments are established

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