Synthesis of multi-arm-star polyglycidols of different architecture grafted with polyacrylate side arms

Well defined linear and 3-, 4-, and 6-arm-star shaped polyglycidols were obtained via anionic ring-opening polymerisation of ethoxyethyl glycidyl ether using 3-phenyl-1-propanol, trimethylolpropane, di(trimethylolpropane, and dipentaerythrite as initiator followed by the removal of the acetal protection group via acid catalysed hydrolysis. The microstructure and architecture of the polymers was proven by NMR spectroscopy, size exclusion chromatography and MALDI-TOF-MS. Multifunctional initiators for the atom transfer radical polymerisation were obtained by esterification of the hydroxyl groups of the polyglycidols with α-bromoisobutyryl bromide. Kinetic studies of the ATRP of tert-butyl acrylate and methyl acrylate revealed a controlled synthesis of linear and multi-arm-star polyglycidols of different architecture grafted with polyacrylate side arms.     

Geometric Currents in Piezoelectricity

As a simple model for piezoelectricity we consider a gas of infinitely many non-interacting electrons subject to a slowly time-dependent periodic potential. We show that in the adiabatic limit the macroscopic current is determined by the geometry of the Bloch bundle. As a consequence we obtain the King-Smith and Vanderbilt formula up to errors smaller than any power of the adiabatic parameter.     

Intracellular Assembly of Interacting Enzymes Yields Highly-Active Nanoparticles for Flow Biocatalysis

All-enzyme hydrogel (AEH) particles with a hydrodynamic diameter of up to 120 nm were produced intracellularly with an Escherichia coli-based in vivo system. The inCell-AEH nanoparticles were generated from polycistronic vectors enabling simultaneous expression of two interacting enzymes, the Lactobacillus brevis alcohol dehydrogenase (ADH) and the Bacillus subtilis glucose-1-dehydrogenase (GDH), fused with a SpyCatcher or SpyTag, respectively. Formation of inCell-AEH was analyzed by dynamic light scattering and atomic force microscopy. Using the stereoselective two-step reduction of a prochiral diketone substrate, we show that the inCell-AEH approach can be advantageously used in whole-cell flow biocatalysis, by which flow reactors could be operated for >4 days under constant substrate perfusion. More importantly, the inCell-AEH concept enables the recovery of efficient catalyst materials for stable flow bioreactors in a simple and economical one-step procedure from crude bacterial lysates. We believe that our method will contribute to further optimization of sustainable biocatalytic processes.     

How it All Started at DESY in 1964

To put it bluntly, synchrotrons and storage rings were originally not intended to become light sources for synchrotron radiation (SR). If particle physicists had not driven this development for their own needs, we would not yet have these sources available at their present level of sophistication. In 1964, when the then-6 GeV synchrotron DESY at the newly founded Hamburg institution of the same name started operating, SR was considered at best a nuisance. Accelerating an electron to 6 GeV was accompanied by a loss of 9.35 GeV on its way due to this radiation, and later, at 7.5 GeV, the loss amounted to 22.8 GeV. How could it then happen that today all of the DESY storage rings and linear accelerators are devoted to SR?