31 research outputs found

    In situ Product Recovery Integrated with Biotransformations

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    Biocatalysis constitutes an effective tool for the production of fine chemicals. In order to widen the spectrum of applicable reaction types to reactions that are constrained by inhibitions, product toxicity, or degradation, an unfavorable position of the thermodynamic equilibrium, or by kinetic control, in situ product removal (ISPR) is an attractive process option to overcome those limitations. To fully exploit the benefits of the ISPR approach, selective removal of the product to an auxiliary phase with high capacity is usually required. Obviously, such an operation becomes increasingly difficult with decreasing differences in the physical properties of substrate(s) and product(s) as it is arguably frequently the case with biotransformations. In this paper we analyze the possibilities to apply ISPR to biotransformations and identify the most promising developments supported by simple model considerations to fully exploit the potential of ISPR

    Lifelong Learning: Anerkennung außerhochschulisch erworbener Kompetenzen

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    "Lifelong Learning via Portfolio" ist ein Kooperationsprojekt der TU Darmstadt und der Hochschule Darmstadt. Der folgende Werkstattbericht skizziert den Diskussionsstand und die Erfahrungen in dem Projekt, welches auf der Grundlage der Weiterentwicklung von Verfahren zur Anerkennung beruflicher Kompetenzen auf HochschulstudiengĂ€nge einen Beitrag zur verbesserten VerknĂŒpfung von beruflicher und hochschulischer Bildung leisten möchte. Im Fokus der Betrachtung stehen die strukturellen VerĂ€nderungen durch den Bologna-Prozess als Ausgangspunkt, die Auswirkungen des demographischen Wandels auf den Bologna-Prozess, der mögliche Zusammenhang von pauschaler und individueller Anrechnung und die Zielsetzungen und Erfahrungen sowie eine Zwischenbilanz des Projekts. 02.11.2011 | Gregor Bechtold, Matthias Knoll & Mario Stephan Seger (Darmstadt) Gregor BECHTOLD, Matthias KNOLL & Mario Stephan SEGER[1] (Darmstadt) [1]E-Mail: [email protected]

    Novel method for high-throughput colony PCR screening in nanoliter-reactors

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    We introduce a technology for the rapid identification and sequencing of conserved DNA elements employing a novel suspension array based on nanoliter (nl)-reactors made from alginate. The reactors have a volume of 35 nl and serve as reaction compartments during monoseptic growth of microbial library clones, colony lysis, thermocycling and screening for sequence motifs via semi-quantitative fluorescence analyses. nl-Reactors were kept in suspension during all high-throughput steps which allowed performing the protocol in a highly space-effective fashion and at negligible expenses of consumables and reagents. As a first application, 11 high-quality microsatellites for polymorphism studies in cassava were isolated and sequenced out of a library of 20 000 clones in 2 days. The technology is widely scalable and we envision that throughputs for nl-reactor based screenings can be increased up to 100 000 and more samples per day thereby efficiently complementing protocols based on established deep-sequencing technologie

    Infiltration from the pedon to global grid scales: an overview and outlook for land surface modelling

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    Infiltration in soils is a key process that partitions precipitation at the land surface in surface runoff and water that enters the soil profile. We reviewed the basic principles of water infiltration in soils and we analyzed approaches commonly used in Land Surface Models (LSMs) to quantify infiltration as well as its numerical implementation and sensitivity to model parameters. We reviewed methods to upscale infiltration from the point to the field, hill slope, and grid cell scale of LSMs. Despite the progress that has been made, upscaling of local scale infiltration processes to the grid scale used in LSMs is still far from being treated rigorously. We still lack a consistent theoretical framework to predict effective fluxes and parameters that control infiltration in LSMs. Our analysis shows, that there is a large variety in approaches used to estimate soil hydraulic properties. Novel, highly resolved soil information at higher resolutions than the grid scale of LSMs may help in better quantifying subgrid variability of key infiltration parameters. Currently, only a few land surface models consider the impact of soil structure on soil hydraulic properties. Finally, we identified several processes not yet considered in LSMs that are known to strongly influence infiltration. Especially, the impact of soil structure on infiltration requires further research. In order to tackle the above challenges and integrate current knowledge on soil processes affecting infiltration processes on land surface models, we advocate a stronger exchange and scientific interaction between the soil and the land surface modelling communities

    ECMO for COVID-19 patients in Europe and Israel

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    Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients

    Scenario set-up and forcing data for impact model evaluation and impact attribution within the third round of the Inter-Sectoral Model Intercomparison Project (ISIMIP3a)

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    This paper describes the rationale and the protocol of the first component of the third simulation round of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a, www.isimip.org) and the associated set of climate-related and direct human forcing data (CRF and DHF, respectively). The observation-based climate-related forcings for the first time include high-resolution observational climate forcings derived by orographic downscaling, monthly to hourly coastal water levels, and wind fields associated with historical tropical cyclones. The DHFs include land use patterns, population densities, information about water and agricultural management, and fishing intensities. The ISIMIP3a impact model simulations driven by these observation-based climate-related and direct human forcings are designed to test to what degree the impact models can explain observed changes in natural and human systems. In a second set of ISIMIP3a experiments the participating impact models are forced by the same DHFs but a counterfactual set of atmospheric forcings and coastal water levels where observed trends have been removed. These experiments are designed to allow for the attribution of observed changes in natural, human and managed systems to climate change, rising CH4 and CO2 concentrations, and sea level rise according to the definition of the Working Group II contribution to the IPCC AR6

    Suitability of teicoplanin–aglycone bonded stationary phase for simulated moving bed enantioseparation of racemic amino acids employing composition-constrained eluents

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    The suitability of a teicoplanin–aglycone based chiral stationary phase for the simulated moving bed (SMB) enantioseparation of amino acids under enzyme-compatible conditions was shown following a procedure that is based solely on model-based simulations and HPLC experiments. A set of eight amino acids could be separated employing aqueous solvent containing only 10% (v/v) methanol, five of them with baseline resolution. The impact of type and concentration of organic modifier and pH modifier and pH on the separation characteristics of racemic methionine was investigated. Invariant elution profiles of repetitive adsorption/desorption of large amounts of methionine representing SMB-like conditions suggest stable adsorption behavior. Competitive loading capacity (20 mg of methionine per g of chiral stationary phase (CSP)) and SMB productivity (1 g of D-methionine per g of CSP per day) were predicted. The applied transport-dispersive model based on a competitive Bi-Langmuir isotherm was validated and its parameter estimated by model-based experimental analysis.

    Directed Divergent Evolution of a Thermostable D-Tagatose Epimerase towards Improved Activity for Two Hexose Substrates

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    Functional promiscuity of enzymes can often be harnessed as the starting point for the directed evolution of novel biocatalysts. Here we describe the divergent morphing of an engineered thermostable variant (Var8) of a promiscuous D-tagatose epimerase (DTE) into two efficient catalysts for the C3 epimerization of D-fructose to D-psicose and of L-sorbose to L-tagatose. Iterative single-site randomization and screening of 48 residues in the first and second shells around the substrate-binding site of Var8 yielded the eight-site mutant IDF8 (ninefold improved kcat for the epimerization of D-fructose) and the six-site mutant ILS6 (14-fold improved epimerization of L-sorbose), compared to Var8. Structure analysis of IDF8 revealed a charged patch at the entrance of its active site; this presumably facilitates entry of the polar substrate. The improvement in catalytic activity of variant ILS6 is thought to relate to subtle changes in the hydration of the bound substrate. The structures can now be used to select additional sites for further directed evolution of the ketohexose epimerase

    Simulator Coupling System (SiCS) - Simulator Integration

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    This document describes the interface between the Simulation Coupling System SiCS and the simulators, which are and will be integrated with SiCS. The integration results in a SiCSbased compound simulator, whereof SiCS represents the kernel system ('backplane') for user interface, synchronization etc. The document is intended to line out the requirements and the effort for the integration of further simulators with SiCS from a simulator's point of view. Therefore the simulator interface functions to be supplied by the integrated simulation systems and the corresponding integration effort are described in the next chapters. 1.2 Short description of SiC
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