Mathematik besiegte in Polen die unvernünftig gebrauchte ENIGMA Teil 1: Vorarbeiten in Polen Im Gedenken an Marian Rejewski (* 16. August 1905)

Ohne Zusammenfassung     

Zur Maßstabsübertragung beim Suspendieren im Rührgefäß

Scale-up of agitated vessels in the case of suspensions . In the scale-up of agitated vessels a decrease of specific power input ε is recommended in the case of suspensions. Up to now it has been assumed that turbulence is the reason for this decrease. This paper shows that there may also be a contribution due to decreasing wall areas causing less wall shear stresses and moreover a reduction of circulation due to lower cross-sectional areas per unit volume of the threads of flow. In the case of so-called ?complete suspension”? according to the ?1-s criterion”?, two mechanisms can be distinguished: On the one hand we have a lifting of solid particles without, and on the other hand such a lifting with formation of bulk accumulations of solids on the bottom of the vessel. In the first case, scale-up can be done as for a homogeneous distribution of the solid material. The specific power input ε is ～ μ⁰ up to ε ～ μ^?1 with the scale-up factor μ. In the second case (formation of dense solids clouds) a relationship ε ～ μ^m with m > 0 was found.     

Influence of electrosorption, solvent, temperature, and ion polarity on the performance of LC-ESI-MS using graphitic carbon for acidic oligosaccharides

Porous graphitic carbon (PGC) emerges as an ideal stationary phase for LC-ESI-MS of complex oligosaccharides. Therefore, we studied the factors influencing detection and elution of charged oligosaccharides from PGC columns coupled to an ESI source. Electrosorption by the carbon surface leads to total retention of very acidic glycans on instruments where voltage is applied to the spray needle. This problem can be eliminated by thorough electrical grounding. A point of general importance is the influence of ionic strength on the elution and peak shape of glycans containing several carboxylic acid groups in the form of sialic acids or uronic acids. Solvent pH had a marginal effect on the ionization efficiency in both ion polarities, but the content of organic solvent strongly influenced signal intensity of acidic glycans in the negative mode. As a consequence, detection in the positive ion mode appears preferable when neutral and charged glycans shall be quantitated in the same sample. While retention of neutral glycans is not affected by pH, sialylated species are retained somewhat stronger at acidic pH resulting in a larger spread of the entire elution range of N-glycans. Remarkably, retention of glycans on PGC increased at higher temperatures.