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131.
Dr. Lukas Kröger Dr. Constantin G. Daniliuc Deeba Ensan Sebastian Borgert Dr. Christian Nienberg Miriam Lauwers Dr. Michaela Steinkrüger Prof. Joachim Jose Dr. Markus Pietsch Prof. Bernhard Wünsch 《ChemMedChem》2020,15(10):871-881
The serine/threonine kinase CK2 modulates the activity of more than 300 proteins and thus plays a crucial role in various physiological and pathophysiological processes including neurodegenerative disorders of the central nervous system and cancer. The enzymatic activity of CK2 is controlled by the equilibrium between the heterotetrameric holoenzyme CK2α2β2 and its monomeric subunits CK2α and CK2β. A series of analogues of W16 ((3aR,4S,10S,10aS)-4-{[(S)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-10-(3,4,5-trimethoxyphenyl)-4,5,10,10a-tetrahydrofuro[3,4-b]carbazole-1,3(3aH)-dione ((+)- 3 a )) was prepared in an one-pot, three-component Levy reaction. The stereochemistry of the tetracyclic compounds was analyzed. Additionally, the chemically labile anhydride structure of the furocarbazoles 3 was replaced by a more stable imide ( 9 ) and N-methylimide ( 10 ) substructure. The enantiomer (−)- 3 a (Ki=4.9 μM) of the lead compound (+)- 3 a (Ki=31 μM) showed a more than sixfold increased inhibition of the CK2α/CK2β interaction (protein-protein interaction inhibition, PPII) in a microscale thermophoresis (MST) assay. However, (−)- 3 a did not show an increased enzyme inhibition of the CK2α2β2 holoenzyme, the CK2α subunit or the mutated CK2α′ C336S subunit in the capillary electrophoresis assay. In the pyrrolocarbazole series, the imide (−)- 9 a (Ki=3.6 μM) and the N-methylimide (+)- 10 a (Ki=2.8 μM) represent the most promising inhibitors of the CK2α/CK2β interaction. However, neither compound could inhibit enzymatic activity. Unexpectedly, the racemic tetracyclic pyrrolocarbazole (±)- 12 , with a carboxy moiety in the 4-position, displays the highest CK2α/CK2β interaction inhibition (Ki=1.8 μM) of this series of compounds. 相似文献
132.
Wachstumsmessungen von Kristallen in sauberen und verunreinigten Lösungen: Einzelkristall vs. Kollektiv 下载免费PDF全文
Information about crystal growth rates and the influence of impurities are essential for the design of industrial crystallization processes. Here, the influence of trivalent metal ions Fe3+ in solution and adsorbed in the crystal on the growth and dissolution rate is investigated. The results clearly show kinetic and thermodynamic effects caused by impurities which have to be taken into account in the equipment design. Furthermore, effects of growth rate dispersion must be excluded by investigation of crystal collectives. Additionally, the crystal growth data should be obtained from real starting solutions. 相似文献
133.
Influence of Microstructure and Surface Activation of Dual‐Phase Membrane Ce0.8Gd0.2O2−δ–FeCo2O4 on Oxygen Permeation 下载免费PDF全文
Madhumidha Ramasamy Stefan Baumann Justinas Palisaitis Falk Schulze‐Küppers Maria Balaguer Daejin Kim Wilhelm A. Meulenberg Jochim Mayer Ramesh Bhave Olivier Guillon Martin Bram 《Journal of the American Ceramic Society》2016,99(1):349-355
Dual‐phase oxygen transport membranes are fast‐growing research interest for application in oxyfuel combustion process. One such potential candidate is CGO‐FCO (60 wt% Ce0.8Gd0.2O2?δ–40 wt% FeCo2O4) identified to provide good oxygen permeation flux with substantial stability in harsh atmosphere. Dense CGO‐FCO membranes of 1 mm thickness were fabricated by sintering dry pellets pressed from powders synthesized by one‐pot method (modified Pechini process) at 1200°C for 10 h. Microstructure analysis indicates presence of a third orthorhombic perovskite phase in the sintered composite. It was also identified that the spinel phase tends to form an oxygen deficient phase at the grain boundary of spinel and CGO phases. Surface exchange limitation of the membranes was overcome by La0.6Sr0.4Co0.2Fe0.8O3?δ (LSCF) porous layer coating over the composite. The oxygen permeation flux of the CGO‐FCO screen printed with a porous layer of 10 μm thick LSCF is 0.11 mL/cm2 per minute at 850°C with argon as sweep and air as feed gas at the rates of 50 and 250 mL/min. 相似文献
134.
Andreas M. Kern Bodo Zierath Joachim Haertlé Tobias Fey Bastian J. M. Etzold 《化学工程与技术》2016,39(6):1121-1129
The influence of graphitization and composition of carbide‐derived carbon (CDC) monoliths on the electrical and thermal conductivity was investigated. Carbon monoliths with varying porosities were synthesized employing biomorphous macroporous TiC and SiC as precursors. Graphitization was carried out in situ during high‐temperature chlorination with and without addition of nickel, iron, and cobalt chloride to the carbide. The graphitized monoliths showed improved properties. The results demonstrate that despite graphitic carbon also glass‐like carbon, stemming from the carbide synthesis, increases the thermal and electrical conductivity significantly. 相似文献
135.
Ketonization of Proline Residues in the Peptide Chains of Actinomycins by a 4‐Oxoproline Synthase 下载免费PDF全文
Dr. Siamak Semsary Dr. Ivana Crnovčić Ronja Driller Dr. Joachim Vater Dr. Bernhard Loll Dr. Ullrich Keller 《Chembiochem : a European journal of chemical biology》2018,19(7):706-715
X‐type actinomycins (Acms) contain 4‐hydroxyproline (Acm X0) or 4‐oxoproline (Acm X2) in their β‐pentapeptide lactone rings, whereas their α ring contains proline. We demonstrate that these Acms are formed through asymmetric condensation of Acm half molecules (Acm halves) containing proline with 4‐hydroxyproline‐ or 4‐oxoproline‐containing Acm halves. In turn, we show—using an artificial Acm half analogue (PPL 1) with proline in its peptide chain—their conversion into the 4‐hydroxyproline‐ and 4‐oxoproline‐containing Acm halves, PPL 0 and PPL 2, in mycelial suspensions of Streptomyces antibioticus. Two responsible genes of the Acm X biosynthetic gene cluster of S. antibioticus, saacmM and saacmN, encoding a cytochrome P450 monooxygenase (Cyp) and a ferredoxin were identified. After coexpression in Escherichia coli, their gene products converted PPL 1 into PPL 0 and PPL 2 in vivo as well as in situ in permeabilized cell of the transformed E. coli strain in conjunction with the host‐encoded ferredoxin reductase in a NADH (NADPH)‐dependent manner. saAcmM has high sequence similarity to the Cyp107Z (Ema) family of Cyps, which can convert avermectin B1 into its keto derivative, 4′′‐oxoavermectin B1. Determination of the structure of saAcmM reveals high similarity to the Ema structure but with significant differences in residues decorating their active sites, which defines saAcmM and its orthologues as a distinct new family of peptidylprolineketonizing Cyp. 相似文献
136.
Jadran Vrabec Martin Bernreuther Hans‐Joachim Bungartz Wei‐Lin Chen Wilfried Cordes Robin Fingerhut Colin W. Glass Jürgen Gmehling René Hamburger Manfred Heilig Matthias Heinen Martin T. Horsch Chieh‐Ming Hsieh Marco Hülsmann Philip Jäger Peter Klein Sandra Knauer Thorsten Köddermann Andreas Köster Kai Langenbach Shiang‐Tai Lin Philipp Neumann Jürgen Rarey Dirk Reith Gábor Rutkai Michael Schappals Martin Schenk Andre Schedemann Mandes Schönherr Steffen Seckler Simon Stephan Katrin Stöbener Nikola Tchipev Amer Wafai Stephan Werth Hans Hasse 《化学,工程师,技术》2018,90(3):295-306
This article outlines advances in molecular modeling and simulation using massively parallel high‐performance computers (HPC). In the SkaSim project, partners from the HPC community collaborated with users from science and industry. The aim was to optimize the prediction of thermodynamic property data in terms of efficiency, quality and reliability using HPC methods. In this context, various topics were dealt with: atomistic simulation of homogeneous gas bubble formation, surface tension of classical fluids and ionic liquids, multicriteria optimization of molecular models, the development of the molecular simulation codes ls1 mardyn and ms2, atomistic simulation of gas separation processes, molecular membrane structure generators, transport resistors and the evaluation of predictive property data models based on specific mixture types. 相似文献
137.
Joachim Vollbrecht Arne Stepen Karlo Nolkemper Susanne Keuker-Baumann Heinz Kitzerow 《Polymer Science Series C》2018,60(1):48-54
Blends consisting of two components, namely a liquid crystalline perylene ester and a bilaterally extended perylene ester, were studied. The liquid crystalline properties of these blends were investigated in detail by means of polarized optical microscopy and differential scanning calorimetry. The resulting phase diagram was used to explore the potential of these blends as emitter layers in OLEDs, which were prepared via thermal evaporation in a vacuum and spin coating of solutions. 相似文献
138.
Nadine Kirchhoff Cathrin Schröder Daniel Stute Prof. Dr.‐Ing. Elmar Moritzer Prof. Dr.‐Ing. Hans‐Joachim Schmid 《化学,工程师,技术》2012,84(9):1584-1589
Wood‐plastic composites (WPC) show a complex and completely different material and flow behavior in comparison to pure polymers. Especially the flow behavior is very important for the processing of these composites. In the following article results of rheological characterization and investigations of the filling behavior during the injection molding process are presented. Furthermore, appearing challenges and possible methods of resolution are discussed. 相似文献
139.
In lightweight walls and floors, the load‐bearing timber members are protected by cladding on the sides to form a divider between two fire compartments or to provide appropriate fire protection to the load‐bearing members. The spaces between the timber members can be void or filled with insulation materials. Although a huge number of different insulation materials exist, the most commonly used material is mineral wool insulation. The existing design model for glass wool‐insulated timber‐frame constructions, given in European standard 1995‐1‐2, assumes collapse of the glass wool after failure of the cladding. However, a new form of glass wool insulation, suitable for use at high maximum service temperatures, is now available in the market. The charring phase after the cladding's failure is known as the post‐protection phase. The behaviour of the new heat‐resistant glass wool in the post‐protection phase is similar to that of stone wool and considerably better than that of traditional glass wool. The protective properties of stone wool have changed over the last decades. Charring is one of the main parameters needed to calculate the resistance of a structure to fire. Based on experimental investigations, this paper describes the analysis of the effect of the insulation with regard to its ability to protect timber members against charring during the post‐protection phase. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
140.