Linear equations depending differentiably on a parameter

We investigate operator functionsT(x) inBanach spaces, depending differentiably (meaning of classC orC ) on a parameterx and enjoying a certain regularity property. Iff is a given differentiable function such that the equationT(x)e=f(x) is solvable for eachx then the existence of a functione is proved which belongs to the same differentiability class asf andT, solving the equationT(x)e(x)f(x) identically inx. As an application we extend a result ofJ. Leiterer [9] and give a comprehensive answer to a question posed byJ.L. Taylor in [15] concerning the exactness of certain cochain complexes.     

3,5-Dinitro-o-toluamide und verwandte Dinitroverbindungen

Ohne Zusammenfassung     

m-Dinitroverbindungen

Ohne Zusammenfassung     

Gradient elution capillary electrochromatography and hyphenation with nuclear magnetic resonance

Coupling of gradient capillary electrochromatography (gradient CEC) and capillary zone electrophoresis (CZE) with nuclear magnetic resonance spectroscopy (NMR) was performed using a recently developed capillary NMR interface. This technique was applied for the analysis of pharmaceuticals and food. An analgesic was investigated using isocratic and gradient continuous-flow CEC-NMR. Comparison of the results demonstrated the superiority of gradient CEC over isocratic CEC. Aspartame and caffeine, both ingredients of soft beverages, were separated and analyzed by continuous flow CZE-NMR. The order of elution could be reversed by altering the pH. This reversal led to an increased sample concentration in the NMR detection cell, thus allowing the acquisition of a totally correlated spectroscopy (TOCSY) two-dimensional (2-D) spectrum of the synthetic peptide aspartame.