Modulformen und quadratische Formen über dem quadratischen ZahlkörperR (\sqrt 5 )

Ohne Zusammenfassung     

Konstruktion ganzer Modulformen halbzahliger Dimension mit ϑ-Multiplikatoren in zwei Variablen

Ohne Zusammenfassung     

Induced removal of dipalmitoyl phosphatidylcholine by the exclusion of fibrinogen from compressed monolayers at air/liquid interfaces

The induced removal of dipalmitoyl phosphatidylcholine (DPPC) by the exclusion of fibrinogen from mixed DPPC/fibrinogen monolayers at compressed air/liquid interfaces was analyzed. The surface pressure-area hysteresis curves of the monolayers at interfaces were obtained by a Langmuir trough. The hysteresis curves of equilibrium fibrinogen adsorption layers suggest that fibrinogen desorption during the area compression stage became significant at a higher bulk concentration of 1000 ppm. For mixed monolayers of DPPC with fibrinogen, the fibrinogen molecules were expelled from the interface upon compression due to the presence of insoluble DPPC molecules. The squeeze-out of fibrinogen molecules evidently removed a significant number of DPPC molecules from the interface, with the extent depending on fibrinogen surface concentration. During the subsequent area expansion stage, fibrinogen molecules entered the interface and participated in the rise of surface pressure. The induced loss of free DPPC molecules at the interface by the expelled fibrinogen molecules during the area compression stage was then evaluated from the hysteresis curves.     

A new homoflavonoid from the seed of Caesalpinia minax Hance

<正>A new homoflavonoid was isolated from the seed of Caesalpinia minax Hance.On the basis of spectral evidences,its structure was established and named as minaxin.     

Über die Erweiterungsfähigkeit der Hilbertschen Modulgruppe

Ohne Zusammenfassung     

Isotope variations of hydrogen,carbon and nitrogen in florae from the Schirmacher Oasis,East Antarctica

Comparative biochemical and isotope-chemical investigations of cosmopolitical plants open up ways of obtaining parameters from different parts of the Earth which are characterised by variations in the habitat due to different environments. As an Antarctic oasis, the Schirmacher Oasis disposes of adequate favourable ecological conditions for the growth of lower plants.

In the present paper, results of isotope studies of lichens, mosses and algae of the Schirmacher Oasis are given and peculiarities of the habitats which influence the isotope contents of the plants are discussed.     

Tagungsberichte

Die Kenntnis der isotopen Zusammensetzung des Kohlenstoffs in Erdgasen gestattet im Zusammenhang init geologischen Parametern unter anderem Schluβfolgerungen über deren Genese zu ziehen. Auβerdem trägt sie zur Klärung der Migrations- und Akkumulationscrscheinungcn von Gasen bei.

Da für die massenspektrometrische Isotopenanalyse sehr reines CO₂ als Meβgas benötigt wird, ist es Aufgabe der Probenchemie, dieses ohne Isotopenfraktionierungen aus gasförmigen Kohlenwasserstoffen mit Hilfe geeigneter Verfahren herzustellen.

Die probenchemisehe Umarbeitung der Erdgaso zu CO₂, für die massenspektrometrisehe Isotopenanalyse am Kohlenstoff ist Gegenstand der Arbeiten verschiedener Autoren. Craig [1] verbrennt das Gas am -Kupferoxidkatalysator in einer Kreislaufapparatur, wobei das Gas mittels einer automatischen Toepler-Punipe mehrmals (dureh den Verbrennungsofen geleitet und das CO₂ in einer Kühlfalle ausgefroren wird. Das gleiche Arbeitsprinzip verwenden Stahl [2, 3, 4]. Colombo u. a. [5, 6], Wasserburg [7] sowie Silverman und Epstein [8]. Vor der Verbrennung wird das Gas gegebenenfalls durch gaschromatographische Trennung in die einzelnen Komponenten (Mcthan, Äthan, Propan und     

Influence of terminal alkyl chain length on helical twisting property of chiral 1,2-propanediol derivatives

In this study,a novel series of chiral 1,2-propanediol derivatives with different terminal alkyl chain length were synthesized and characterized by FT-IR,~1H NMR and DSC.After doped into a nematic liquid crystal host,all the chiral dopants induced chiral nematic liquid crystals exhibiting a helix inversion with temperature variation.The results indicate that terminal alkyl chain length has a prominent influence on helical twisting property of the chiral dopants.With increasing the terminal alkyl chain le...