The establishment of polarity in the embryo is fundamental for the correct development of an organism [1]. The first cleavage of the Caenorhabditis elegans embryo is asymmetric with certain cytoplasmic components being distributed unequally between the daughter cells [2-4]. Using a genetic screen, Kemphues and co-workers have identified six par genes (partition-defective) [5,6], which are involved in the process of asymmetric division. One of these genes encodes a highly conserved protein, PAR-1, which is a serine/threonine kinase that localizes asymmetrically to the posterior part of the zygote and to those blastocysts that give rise to the germ line [7-9]. We reasoned that the mammalian homologue of PAR-1 (mPAR-1) might be involved in the process of polarization of epithelial cells, which consist of apical and basolateral membrane domains. We found that mPAR-1 was expressed in a wide variety of epithelial tissues and cell lines and was associated with the cellular cortex. In polarized epithelial cells, mPAR-1 was asymmetrically localized to the lateral domain. A fusion protein lacking the kinase domain had the same localization as the full-length protein but its prolonged expression acted in a dominant-negative fashion: lateral adhesion of the transfected cells to neighbouring cells was diminished, resulting in the former cells being 'squeezed out' from the monolayer. Moreover, the polarity of these cells was disturbed resulting in mislocalization of E-cadherin. Thus, in the C. elegans embryo and in epithelial cells, polarity appears to be governed by similar mechanisms.

Power-togas (PtG) is widely expected to play a valuable role in future renewable energy systems. In addition to partly allowing a further utilization of the existing gas infrastructure for energy transport and storage, hydrogen or synthetic natural gas (SNG) from electric power represents a high-density energy carrier and important feedstock material for further processing. This premise leads to a significant demand for large-scale PtG plants, which was evaluated with an amount of up to 14.2 TWel at a global scale. Together with the upscaling of single-MW plants available today, this will enable to achieve appropriate cost reduction effects through technological learning. These effects were evaluated in the present paper via a holistic techno-economic assessment of different PtG plant configurations, resulting in the reduction of SNG production costs down to 100 €/MWhSNG by 2030 and below 60 €/MWhSNG by 2050, according to the supplying electricity source.

Technological learning is a major aspect in the assessment of potential cost reductions for emerging energy technologies. Since the evaluation of experience curves requires the observation of production costs over several magnitudes of produced units, an early estimation of potential future technology implementation costs often presumes a certain degree of maturity. In this paper, we propose a calculation model for learning curves on the component or production process level, which allows to incorporate experience and knowledge on cost reduction potentials on a low level. This allows interchangeability between similar technologies, which is less feasible on a macro level. Additionally, the model is able to consider spill-over effects from concurrent technology usages for the inclusion of peripheral standard components for the assessment in an overall system view. The application of the model to the power-togas technology, especially water electrolysis, has shown, that the results are comparable to conventional approaches at the stack level, while providing transferability between different cell designs. In addition, the investigations made at the system level illustrate that the consideration of spill-over effects can be a relevant factor in the evaluation of cost reduction potentials, especially for technologies in an early commercial state with low numbers of cumulative productions.

This study investigates the theoretical potential and limitations of green carbon dioxide sources for technical valorisation approaches. The emission of greenhouse gases, especially CO2, must be rigorously reduced in order to achieve the European and global climate objectives. As CO2 is an increasingly valuable resource for industries and new disrupting technologies on CO2 utilization, the potential of CO2 obtained from different green and fossil sources in Europe is discussed for a comparative evaluation. Biogenic or green and fossil CO2 sources are classified according to their emitting processes and industry sectors, respectively. The CO2 potentials are then calculated from statistical data for CO2 generating processes in Europe, complemented and verified by relevant papers and reports. This study demonstrates the European potential of capturing and utilizing the biogenic and fossil CO2. In Europe, 69.7 Mt/a CO2 are estimated to be produced by biogas upgrading, biogas combustion, as well as bioethanol and other fermentation processes. Additionally, 437 Mt/a CO2 are produced by solid biomass combustion. This accounts for a theoretical potential of 506.7 Mt/a CO2 currently available, which is nearly seven times the amount of the current European industrial CO2 demand. The CO2 from biomass combustion is more difficult to capture and is mixed with impurities, which potentially reduces its technical and economic potential, whereas the 63 Mt/a from other high-purity sources are already partially utilized, e.g., by breweries or dry ice producers.

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