SummaryMetabolic Engineering aims at the systematic analysis and targeted manipulation of the met... more SummaryMetabolic Engineering aims at the systematic analysis and targeted manipulation of the metabolism in biotechnologically utilized microorganisms [1,2]. Recently, consistent stationary in vivo data sets of intracellular metabolite concentrations, fluxes and specific enzyme activities have become available for this purpose [3,4]. For the integrative analysis of the metabolic data at hand, a novel multi-scale modeling concept, computeralgebraic methods and efficient numerical algorithms are proposed. The available metabolic data are typically afflicted with comparatively large measurement errors. Therefore, reliable comprehensive error estimations are essential for the reasonable interpretation of consecutive outcomes, such as simulation results. The concepts, methods and algorithms are first presented as universal methods and subsequently applied to the anaplerotic regulation in lysine-producing Corynebacterium glutamicum. A multi-scale model is set up, fitted to the available e...
Ds 75 1 Proceedings of the 19th International Conference on Engineering Design Design For Harmonies Vol 1 Design Processes Seoul Korea 19 22 08 2013, 2013
Ds 75 1 Proceedings of the 19th International Conference on Engineering Design Design For Harmonies Vol 1 Design Processes Seoul Korea 19 22 08 2013, 2013
Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatme... more Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially increase due to 2D variable-range hopping conduction through small graphene domains in an RGO sheet containing defect regions of residual sp3 carbon clusters bonded to oxygen groups, whereas RGO sheets prepared in a closed container under moderate pressure showed linear I-V characteristics with a conductivity of 267.2−537.5 S/m. It was found that the chemical reduction under pressure results in larger graphene domains (sp2 networks) in the RGO sheets when compared to that prepared under atmospheric pressure, indicating that the present reduction of GO sheets under the pressure is one of the effective methods to make well-reduced GO sheets.
A general methodology is presented for the modeling, simulation, design, evaluation, and statisti... more A general methodology is presented for the modeling, simulation, design, evaluation, and statistical analysis of (13)C-labeling experiments for metabolic flux analysis. The universal software framework 13C-FLUX was implemented to support all steps of this process. Guided by the example of anaplerotic flux determination in Corynebacterium glutamicum, the technical details of the model setup, experimental design, and data evaluation are discussed. It is shown how the network structure, the input substrate composition, the assumptions about fluxes, and the measurement configuration are specified within 13C-FLUX. Based on the network model, different experimental designs are computed depending on the goal of the investigations. Finally, a specific experiment is evaluated and the various statistical methods used to analyze the results are briefly explained. The appendix gives some details about the software implementation and availability.
In this article some of the critical aspects of Web 2.0 are mapped in relation to labor and the p... more In this article some of the critical aspects of Web 2.0 are mapped in relation to labor and the production of user generated content. For many years the Internet was considered an apt technology for subversion of capitalism by the Italian post-Marxists. What we have witnessed, however, is that the Internet functions as a double-edged sword; the infrastructure does foster democracy, participation, joy, creativity and sometimes creates zones of piracy. But, at the same time, it has become evident how this same infrastructure also enables companies easily to piggyback on user generated content. Different historical and contemporary examples are provided to map how the architecture of participation sometimes turns into an architecture of exploitation.
The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine c... more The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine copepod Acartia tonsa were tested in 48-h tests at two salinities, 18 and 28. For LAS 48-h median lethal concentration (LC50) values were 2.1 and 8.8 mg/L, respectively. For TBT the 48-h ...
The effects of tri-butyl-tin (TBT) on autotrophic pico-, nano and microplankton were assessed by ... more The effects of tri-butyl-tin (TBT) on autotrophic pico-, nano and microplankton were assessed by a marine enclosure experiment. In accordance with the pollution-induced community tolerance (PICT) concept, an increased tolerance was found for microplankton in enclosures amended with 0.01, 0.6 and 10 nM TBT. In contrast, nanoplankton showed increased tolerance only in an enclosure amended with 10 nM TBT. Neither the entire phytoplankton community nor picoplankton showed increased tolerance. These observations are discussed in terms of the ecology of pico-, nano- and microplankton. In all enclosures amended with TBT, primary production by nanoplankton declined, and primary production by picoplankton increased: changes that are interpreted as indirect effects of TBT. A comparison of TBT levels found in polluted coastal areas and in off-shore areas indicates that phytoplankton communities might be affected by TBT. Size fractionated measurements of TBT tolerance in phytoplankton communities were proven to increase the sensitivity of the PICT concept.
SummaryMetabolic Engineering aims at the systematic analysis and targeted manipulation of the met... more SummaryMetabolic Engineering aims at the systematic analysis and targeted manipulation of the metabolism in biotechnologically utilized microorganisms [1,2]. Recently, consistent stationary in vivo data sets of intracellular metabolite concentrations, fluxes and specific enzyme activities have become available for this purpose [3,4]. For the integrative analysis of the metabolic data at hand, a novel multi-scale modeling concept, computeralgebraic methods and efficient numerical algorithms are proposed. The available metabolic data are typically afflicted with comparatively large measurement errors. Therefore, reliable comprehensive error estimations are essential for the reasonable interpretation of consecutive outcomes, such as simulation results. The concepts, methods and algorithms are first presented as universal methods and subsequently applied to the anaplerotic regulation in lysine-producing Corynebacterium glutamicum. A multi-scale model is set up, fitted to the available e...
Ds 75 1 Proceedings of the 19th International Conference on Engineering Design Design For Harmonies Vol 1 Design Processes Seoul Korea 19 22 08 2013, 2013
Ds 75 1 Proceedings of the 19th International Conference on Engineering Design Design For Harmonies Vol 1 Design Processes Seoul Korea 19 22 08 2013, 2013
Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatme... more Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially increase due to 2D variable-range hopping conduction through small graphene domains in an RGO sheet containing defect regions of residual sp3 carbon clusters bonded to oxygen groups, whereas RGO sheets prepared in a closed container under moderate pressure showed linear I-V characteristics with a conductivity of 267.2−537.5 S/m. It was found that the chemical reduction under pressure results in larger graphene domains (sp2 networks) in the RGO sheets when compared to that prepared under atmospheric pressure, indicating that the present reduction of GO sheets under the pressure is one of the effective methods to make well-reduced GO sheets.
A general methodology is presented for the modeling, simulation, design, evaluation, and statisti... more A general methodology is presented for the modeling, simulation, design, evaluation, and statistical analysis of (13)C-labeling experiments for metabolic flux analysis. The universal software framework 13C-FLUX was implemented to support all steps of this process. Guided by the example of anaplerotic flux determination in Corynebacterium glutamicum, the technical details of the model setup, experimental design, and data evaluation are discussed. It is shown how the network structure, the input substrate composition, the assumptions about fluxes, and the measurement configuration are specified within 13C-FLUX. Based on the network model, different experimental designs are computed depending on the goal of the investigations. Finally, a specific experiment is evaluated and the various statistical methods used to analyze the results are briefly explained. The appendix gives some details about the software implementation and availability.
In this article some of the critical aspects of Web 2.0 are mapped in relation to labor and the p... more In this article some of the critical aspects of Web 2.0 are mapped in relation to labor and the production of user generated content. For many years the Internet was considered an apt technology for subversion of capitalism by the Italian post-Marxists. What we have witnessed, however, is that the Internet functions as a double-edged sword; the infrastructure does foster democracy, participation, joy, creativity and sometimes creates zones of piracy. But, at the same time, it has become evident how this same infrastructure also enables companies easily to piggyback on user generated content. Different historical and contemporary examples are provided to map how the architecture of participation sometimes turns into an architecture of exploitation.
The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine c... more The acute toxicities of linear alkylbenzene sulfonate (LAS) and tributyltin (TBT) to the marine copepod Acartia tonsa were tested in 48-h tests at two salinities, 18 and 28. For LAS 48-h median lethal concentration (LC50) values were 2.1 and 8.8 mg/L, respectively. For TBT the 48-h ...
The effects of tri-butyl-tin (TBT) on autotrophic pico-, nano and microplankton were assessed by ... more The effects of tri-butyl-tin (TBT) on autotrophic pico-, nano and microplankton were assessed by a marine enclosure experiment. In accordance with the pollution-induced community tolerance (PICT) concept, an increased tolerance was found for microplankton in enclosures amended with 0.01, 0.6 and 10 nM TBT. In contrast, nanoplankton showed increased tolerance only in an enclosure amended with 10 nM TBT. Neither the entire phytoplankton community nor picoplankton showed increased tolerance. These observations are discussed in terms of the ecology of pico-, nano- and microplankton. In all enclosures amended with TBT, primary production by nanoplankton declined, and primary production by picoplankton increased: changes that are interpreted as indirect effects of TBT. A comparison of TBT levels found in polluted coastal areas and in off-shore areas indicates that phytoplankton communities might be affected by TBT. Size fractionated measurements of TBT tolerance in phytoplankton communities were proven to increase the sensitivity of the PICT concept.
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