Literatur

Ohne Zusammenfassung     

Direct Modulation of Small GTPase Activity and Function

Small GTPases are a family of GDP‐/GTP‐binding proteins that serve as biomolecular switches inside cells to control a variety of essential cellular processes. Aberrant function and regulation of small GTPases is associated with a variety of human diseases, thus rendering these proteins highly interesting targets in drug discovery. However, this class of proteins has been considered “undruggable”, as intensive decade‐long efforts did not yield clinically relevant direct modulators of small GTPases. Recently, the targeting of small GTPases has gained fresh impetus through the discovery of novel transient cavities on the protein surfaces and the application of new targeting strategies. Besides Ras proteins, other small GTPases have attracted increased attention since improved biological insight in combination with novel targeting strategies identified them as promising targets in drug discovery. This Review gives an overview of relevant aspects of the superfamily of small GTPases and summarizes recent progress and perspectives for the direct modulation of these challenging targets.     

Neue Methoden zum Nachweis, zur Bestimmung und Trennung des Nickels

Ohne Zusammenfassung     

Bestimmung von Nickel, Kobalt, Kupfer, Eisen und Zink in Molybd?n und Wolfram

Zusammenfassung Durch Kationenaustauschtrennung wird die Summe der Spurenverunreinigungen von Molybdän bzw. Wolfram abgetrennt. Anschließend trennt man die Verunreinigungselemente durch Anionenaustauschchromatographie voneinander und bestimmt in den einzelnen Fraktionen Nickel, Kobalt, Kupfer und Eisen spektrophotometrisch sowie Zink durch inverse Voltammetrie. Die Nachweisgrenzen betragen für 0,5 g-Einwaagen 0,5 ppm Nickel, 0,5 ppm Kobalt, 0,5 ppm Kupfer, 1 ppm Eisen und 5 ppm Zink.

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Summary The sum of trace impurities in molybdenum or tungsten is separated by cation-exchange chromatography, before separating the impurities from each other by anion-exchange chromatography. In different parts of the eluate nickel, cobalt, copper, and iron are determined spectrophotometrically whereas zinc is determined by anodic-stripping voltammetry. The limits of detection are 0.5 ppm for nickel, cobalt, and copper, 1 ppm for iron and 5 ppm for zinc related to 0.5 g of molybdenum or tungsten.

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Herrn Prof. Dr. W. Geilmann zum 75. Geburtstag gewidmet.     

Partial inner product spaces. II. Operators

We study linear operators between nondegenerate partial inner product spaces and their relationships to selfadjoint operators in a “middle” Hilbert space.