Als Beitrag zur Analyse von Poly?thylenglykolen und ihren Mono?thern

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Zur mikroma\analytischen Bestimmung von Sulfat in Thoriumnitrat und Reagenschemikalien

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Die Bestimmung von Thoriumdioxidgehalten in Monazitsand und seinen Begleitmineralien aus Taiwan

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Zur quantitativen Elektronenstrahlmikroanalyse dünner Si?O-Schichten

The electron probe microanalysis of thin isolating films requires evaporating a conductible surfacing. A possible correction of surfacing influence on to the analysis is shown. The oxidation degree n in SiO_n was determined using an absorption and atomic number correction resulting in a good aggreement with chemical analysis.     

A Mass-Spectrometry-Based Approach to Distinguish Annular and Specific Lipid Binding to Membrane Proteins

Membrane proteins engage in a variety of contacts with their surrounding lipids, but distinguishing between specifically bound lipids, and non-specific, annular interactions is a challenging problem. Applying native mass spectrometry to three membrane protein complexes with different lipid-binding properties, we explore the ability of detergents to compete with lipids bound in different environments. We show that lipids in annular positions on the presenilin homologue protease are subject to constant exchange with detergent. By contrast, detergent-resistant lipids bound at the dimer interface in the leucine transporter show decreased k_off rates in molecular dynamics simulations. Turning to the lipid flippase MurJ, we find that addition of the natural substrate lipid-II results in the formation of a 1:1 protein–lipid complex, where the lipid cannot be displaced by detergent from the highly protected active site. In summary, we distinguish annular from non-annular lipids based on their exchange rates in solution.