A synthetic polymer, polyethyleneimine containing dodecyl (C(12)H(25))-chains for binding sites and imidazole moieties for functional catalytic groups, catalyzes the hydrolysis of phenolic sulfate esters by a two-step mechanism resembling that of the corresponding natural enzyme. Quantitative rate studies give kinetic parameters that show that the polymer (synzyme) accelerates the rate 10(12)-f...

An artificial neural network has been used to determine the volume flux and rejections of Ca2+ , Na+ and Cl¯, as a function of transmembrane pressure and concentrations of Ca2+, polyethyleneimine, and polyacrylic acid in water softening by nanofiltration process in presence of polyelectrolytes. The feed-forward multi-layer perceptron artificial neural network including an eight-neuron hidde...

Hybrid brushes composed of two liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI), were synthesized on Si wafers by the "grafting to" method and by applying a combinatorial approach (fabrication of gradient brushes). The combinatorial approach revealed a strong effect of "layer assisted tethering", which allowed us to synthesize hybrid brush...

The present paper describes a new planar multielectrode array (the MED probe) and its electronics (the MED system) which perform electrophysiological studies on acute hippocampal slices. The MED probe has 64 planar microelectrodes, is covered with a non-toxic, uniform insulation layer, and is further coated with polyethylenimine and serum. The MED probe is shown to be appropriate for both stimu...

A simple, general method for purifying restriction endonucleases is described. The method employs precipitation of nucleic acids from crude extracts with polyethyleneimine followed by affinity chromatography on columns of heparin covalently linked to agarose. Most of the sixteen enzymes tested could be purified to a degree sufficient for DNA sequencing work by this method sometimes supplemented...

Volatile impurities contained in polyethyleneimine (PEI), and identified as ethyleneimine dimers and trimers, are reported. These N-based molecules show a strong reducing character, as demonstrated by the change in electrical conductivity of organic (semi)conductors exposed to the PEI vapor. The results prove that electron transfer rather than a dipole effect at the electrode interface is the o...

Supramolecular complexes of PEI(OA)x show a lamellar structure, and reversible crystal phase transition of the side alkyl chains in the complex can be observed by temperature-variable FT-IR spectroscopy.