Energy Efficiency, Materials and Resources (EMR): Energy-Efficient Processes -Multiphases and thermal processes-

Besides the activities on development of technologies and systems for the plasma heating in the FUSION Program, IHM is also in charge of research and development in the topic Energy Efficient Processes, part of the EMR Program. An important part of this research is the dielectric characterization of the processed materials in the parameter range relevant to processes under development. Therefore existing test-sets are continuously improved and new test-sets are developed following the new requirements regarding materials compositions or process parameter range. Meanwhile a very versatile test lab for dielectric characterization exists. This allows temperature dependent dielectric measurements in the frequency range from 10 MHz to 30 GHz for low as well as high loss materials and from room temperature up to 1000°C for solids, liquids and at pressures up to 20 bar. All this expertise and the existing industrial scale high power microwave infrastructure faces growing interest from industry and research. As a consequence the research group is involved in several national and international joint research projects with objectives in various fields of applications. The H2020 project SYMBIOBTIMA requests the design of an industrial prototype reactor for the microwave assisted depolymerization of PET plastic waste for the purpose of energy efficient recycling. In the frame of the H2020 Marie Curie international training network TOMOCON that started end of 2017 a microwave tomographic sensor will be developed. Within the German-Korean project REINFORCE the potential of microwave dielectric heating as well as microwave sustained plasma heating will be investigated with respect to energy efficient carbon fiber production. Solid state microwave amplifiers getting more and more competitive compared to magnetron sources with respect to power and costs. Furthermore such amplifiers allow precise control not only of power level but also of frequency and phase and promise significant longer lifetime than magnetrons. Those features might be door openers for novel application that could not be satisfied with magnetron sources. Therefore national funded collaboration projects have been started with HBH microwave GmbH recently to develop affordable high power solid state generators that meet the requirements for novel process control concepts. Furthermore those novel microwave sources might be useful for microwave sustained plasma generators for plasma activation of CO2 in the frame of research activities like Power to X. Therefore recently a novel lab for plasma chemistry using atmospheric microwave plasma has been established. The status of major projects is briefly introduced in the following chapters

Fast Flux-Activated Leakage Reduction for Superconducting Quantum Circuits

Quantum computers will require quantum error correction to reach the low error rates necessary for solving problems that surpass the capabilities of conventional computers. One of the dominant errors limiting the performance of quantum error correction codes across multiple technology platforms is leakage out of the computational subspace arising from the multi-level structure of qubit implementations. Here, we present a resource-efficient universal leakage reduction unit for superconducting qubits using parametric flux modulation. This operation removes leakage down to our measurement accuracy of $7\cdot 10^{-4}$ in approximately $50\, \mathrm{ns}$ with a low error of $2.5(1)\cdot 10^{-3}$ on the computational subspace, thereby reaching durations and fidelities comparable to those of single-qubit gates. We demonstrate that using the leakage reduction unit in repeated weight-two stabilizer measurements reduces the total number of detected errors in a scalable fashion to close to what can be achieved using leakage-rejection methods which do not scale. Our approach does neither require additional control electronics nor on-chip components and is applicable to both auxiliary and data qubits. These benefits make our method particularly attractive for mitigating leakage in large-scale quantum error correction circuits, a crucial requirement for the practical implementation of fault-tolerant quantum computation

Entwicklung von Bausystemplatten auf Schaumglasbasis mit abgestimmtem Beschichtungssystem Abschlussbericht

SIGLEAvailable from TIB Hannover: F01B1239 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDeutsche Bundesstiftung Umwelt, Osnabrueck (Germany)DEGerman

Tau stabilizes microtubules by binding at the interface between tubulin heterodimers.

The structure, dynamic behavior, and spatial organization of microtubules are regulated by microtubule-associated proteins. An important microtubule-associated protein is the protein Tau, because its microtubule interaction is impaired in the course of Alzheimer’s disease and several other neurodegenerative diseases. Here, we show that Tau binds to microtubules by using small groups of evolutionary conserved residues. The binding sites are formed by residues that are essential for the pathological aggregation of Tau, suggesting competition between physiological interaction and pathogenic misfolding. Tau residues in between the microtubule-binding sites remain flexible when Tau is bound to microtubules in agreement with a highly dynamic nature of the Tau–microtubule interaction. By binding at the interface between tubulin heterodimers, Tau uses a conserved mechanism of microtubule polymerization and, thus, regulation of axonal stability and cell morphology

Structural basis for the regulatory interaction of the methylglyoxal synthase MgsA with the carbon flux regulator Crh in Bacillus subtilis.

Utilization of energy-rich carbon sources such as glucose is fundamental to the evolutionary success of bacteria. Glucose can be catabolized via glycolysis for feeding the intermediary metabolism. The methylglyoxal synthase MgsA produces methylglyoxal from the glycolytic intermediate dihydroxyacetone phosphate. Methylglyoxal is toxic, requiring stringent regulation of MgsA activity. In the Gram-positive bacterium Bacillus subtilis, an interaction with the phosphoprotein Crh controls MgsA activity. In the absence of preferred carbon sources, Crh is present in the nonphosphorylated state and binds to and thereby inhibits MgsA. To better understand the mechanism of regulation of MgsA, here we performed biochemical and structural analyses of B. subtilis MgsA and of its interaction with Crh. Our results indicated that MgsA forms a hexamer (i.e. a trimer of dimers) in the crystal structure, whereas it seems to exist in an equilibrium between a dimer and hexamer in solution. In the hexamer, two alternative dimers could be distinguished, but only one appeared to prevail in solution. Further analysis strongly suggested that the hexamer is the biologically active form. In vitro cross-linking studies revealed that Crh interacts with the N-terminal helices of MgsA and that the Crh-MgsA binding inactivates MgsA by distorting and thereby blocking its active site. In summary, our results indicate that dimeric and hexameric MgsA species exist in an equilibrium in solution, that the hexameric species is the active form, and that binding to Crh deforms and blocks the active site in MgsA

Burial of the polymorphic residue 129 in amyloid fibrils of prion stop mutants.

Misfolding of the natively alpha-helical prion protein into a beta-sheet rich isoform is related to various human diseases such as Creutzfeldt-Jakob disease and Gerstmann-Straeussler-Scheinker-like syndrome. In humans the disease phenotype is modified by a methionine/valine polymorphism at codon 129 of the prion protein gene. Using a combination of H/D exchange coupled to NMR spectroscopy, hydroxyl radical probing detected by mass spectrometry and site-directed mutagenesis we demonstrate that stop mutants of the human prion protein have a conserved amyloid core. The 129 residue is deeply buried in the amyloid core structure and its mutation strongly impacts aggregation. Taken together the data support a critical role of the polymorphic residue 129 of the human prion protein in aggregation and disease