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991.
Core/Shell and Hollow Ultra High Molecular Weight Polyethylene Nanofibers and Nanoporous Polyethylene Prepared by Mesoscopic Shape Replication Catalysis
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Georg F. J. Müller Markus Stürzel Rolf Mülhaupt 《Advanced functional materials》2014,24(19):2860-2864
Polyvinyl alcohol (PVA) nanofibers, produced by electrospinning, represent attractive high‐surface‐area supports for olefin polymerization catalysts. Tethered with metal alkyls, PVA nanofibers immobilize a great variety of transition metal compounds, thus producing highly active nanofiber‐supported Ziegler‐, metallocene‐, and post‐metallocene catalysts. Whereas most conventional heterogeneous polymerization catalysts form particles, PVA‐nanofiber‐supported catalysts enable polyolefin nanofiber and nanostructure formation by mesoscopic shape replication using electrospun nanofibers as templates. At low ethylene pressure, linear correlation between average PE/PVA core/shell fiber diameter and polymerization time are made. At elevated pressure, this control is lost, accounting for the formation of reactor blends consisting of PE granules and built‐in PE/PVA nanofibers. Whereas conventional catalysts produce micrometer‐sized particles of ultrahigh molecular weight PE (UHMWPE), PVA‐nanofiber supported chromium catalysts afford new families UHMWPE materials. They range from UHMWPE/PVA core/shell nanofibers and nonwovens to hollow UHMWPE fibers and nanoporous UHMWPE, obtained by removing the PVA component. 相似文献
992.
Dr. Mariusz Jaremko Dr. Łukasz Jaremko Karin Giller Dr. Stefan Becker Prof. Dr. Markus Zweckstetter 《Chembiochem : a European journal of chemical biology》2015,16(10):1483-1489
Ligands of the transmembrane protein TSPO are used for imaging of brain inflammation, but a common polymorphism in TSPO complicates their application to humans. Here we determined the three‐dimensional structure and side‐chain dynamics of the A147T polymorph of mammalian TSPO in complex with the first‐generation ligand PK11195. We show that A147T TSPO is able to retain the same structural and dynamic profile as the wild‐type protein and thus binds PK11195 with comparable affinity. Our study is important for the design of more potent diagnostic and therapeutic ligands of TSPO. 相似文献
993.
Tim Peppel Dominik Seeburg Gerhard Fulda Markus Kraus Ulf Trommler Ulf Roland Sebastian Wohlrab 《化学工程与技术》2017,40(1):153-161
Oxygen removal to very low residual contents in methane‐rich gas streams and carbon dioxide as co‐component (simulated biogas) was achieved via three different methods at various temperatures, namely, by reduction with hydrogen admixtures on Pt/γ‐Al2O3 catalysts, by oxygen absorption affinity of YBaCo4O7+δ, and by the catalytic reaction with methane on both the materials, respectively. The three methods have characteristic advantages and disadvantages which are discussed in the context of existing methods for gas treatments focused on oxygen removal. Finally, the advantage of dielectric radio‐frequency heating on the powdered functional materials is suggested as alternative to conventional routes. 相似文献
994.
Markus Wittmann Thomas Zeiser Georg Hager Gerhard Wellein 《Computers & Mathematics with Applications》2013,65(6):924-935
Several possibilities exist to implement the propagation step of lattice Boltzmann methods. This paper describes common implementations and compares the number of memory transfer operations they require per lattice node update. A performance model based on the memory bandwidth is then used to obtain an estimation of the maximum achievable performance on different machines. A subset of the discussed implementations of the propagation step are benchmarked on different Intel- and AMD-based compute nodes using the framework of an existing flow solver that is specially adapted to simulate flow in porous media, and the model is validated against the measurements. Advanced approaches for the propagation step like “A–A pattern” or “Esoteric Twist” require more programming effort but often sustain significantly better performance than non-naïve but straightforward implementations. 相似文献
995.
Charis Kalogirou Martin Spahn Markus Krebs Steven Joniau Evelyne Lerut Maximilian Burger Claus-Jürgen Scholz Susanne Kneitz Hubertus Riedmiller Burkhard Kneitz 《International journal of molecular sciences》2013,14(11):21414-21434
The treatment of high-risk prostate cancer (HRPCa) is a tremendous challenge for uro-oncologists. The identification of predictive moleculobiological markers allowing risk assessment of lymph node metastasis and systemic progression is essential in establishing effective treatment. In the current study, we investigate the prognostic potential of miR-205 in HRPCa study and validation cohorts, setting defined clinical endpoints for both. We demonstrate miR-205 to be significantly down-regulated in over 70% of the HRPCa samples analysed and that reconstitution of miR-205 causes inhibition of proliferation and invasiveness in prostate cancer (PCa) cell lines. Additionally, miR-205 is increasingly down-regulated in lymph node metastases compared to the primary tumour indicating that miR-205 plays a role in migration of PCa cells from the original location into extraprostatic tissue. Nevertheless, down-regulation of miR-205 in primary PCa was not correlated to the synchronous presence of metastasis and failed to predict the outcome for HRPCa patients. Moreover, we found a tendency for miR-205 up-regulation to correlate with an adverse outcome of PCa patients suggesting a pivotal role of miR-205 in tumourigenesis. Overall, we showed that miR-205 is involved in the development and metastasis of PCa, but failed to work as a useful clinical biomarker in HRPCa. These findings might have implications for the use of miR-205 as a prognostic or therapeutic target in HRPCa. 相似文献
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998.
Dr. Chi Chung Lee Dr. Nathaniel S. Sickerman Prof. Dr. Yilin Hu Prof. Dr. Markus W. Ribbe 《Chembiochem : a European journal of chemical biology》2016,17(6):453-455
A recent electrochemical investigation suggests that the mononuclear molybdenum enzyme YdeY utilizes redox‐active ligands during catalysis. 相似文献
999.
To analyze the challenge of large-scale integration of renewables during the next decades, we present a conceptual power system model that bridges the gap between long term investment allocation and short-term system operation decisions. It integrates dynamic investments in generation, transmission and storage capacities as well as short-term variability and spatial distribution of supply and demand in a single intertemporal optimization framework. Large-scale grid topology, power flow distributions and storage requirements are determined endogenously. Results obtained with a three region model application indicate that adequate and timely investments in transmission and storage capacities are of great importance. Delaying these investments, which are less costly than investments in generation capacities, leads to system-wide indirect effects, such as non-optimal siting of renewable generation capacities, decreasing generation shares of renewables, increasing residual emissions and hence higher overall costs. 相似文献
1000.
Thorsten N. Klauke Thomas M.A. Gronewold Markus Perpeet Susanne Plattes Brigitte Petersen 《Meat science》2013
Aim of the study was the application of biosensor technique to measure the concentration of an acute phase protein (APP) within complex matrices from animal origin. For the first time, acute phase protein haptoglobin (Hp) was detected from unpurified meat juice of slaughter pigs by a label-free biosensor-system, the SAW-based sam®5 system. The system uses a sensor chip with specific antibodies to catch Hp while the mass-related phase shift is measured. The concentration is calculated as a function of these measured phase shifts. The results correlate very well with reference measurement results obtained by enzyme-linked immunosorbent assay (ELISA), R = 0.98. The robust setup of the surface acoustic wave (SAW)-based system and its ability to measure within very short time periods qualifies it for large-scale analyses and is apt to identify rapidly pigs in the meat production process whose consumption would have an increased risk for consumers. 相似文献