X-ray diffraction measurements on PE 2000 between 10 K and 300

Summary It was possible to obtain film exposures of the WAXS-diagram (2 50°) of a PE-fraction in the temperature range from 10 K to 300 K by using a special low temperature Guinier-chamber. The crystallographica-,b-andc-axis has been calculated from the positions of all reflexions. The different behaviour of their expansion coefficients can be explained by activation of rotational- and torsional-vibrations. If we take the number of net planes as constant and consider a temperature-independent part resulting from paracrystalline disorder (built up during crystallization), we can describe the linear increasing of the integral widths of the reflexions with decreasing temperature (10 ... 100%) with building up of inherent stresses inside the crystals.

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Zusammenfassung Eine spezielle Tieftemperatur-Guinier-Kammer ermöglichte es, Filmaufnahmen der Röntgenweitwinkelstreukurve (2 50°) einer hochkristallinen Polyäthylen-Fraktion im Bereich von ca. 10 K bis 300 K zu erhalten. Das unterschiedliche Temperaturverhalten der Ausdehnungskoeffizienten der kristallographischena-,b- undc-Achse, berechnet aus der Lage aller auswertbaren Reflexe, kann durch Anregung von Torsions- und Rotationsschwingungen erklärt werden. Unter der Annahme konstanter Kristallitgrößen sowie eines temperaturunabhängigen parakristallinen Gitterstörungsanteils (hervorgerufen durch Defekteinbau bei der Kristallisation), kann die starke Zunahme der integralen Breiten der Reflexe (bis ca. 100%) zu tiefen Temperaturen auf Eigenspannungen in den Kristalliten zurückgeführt werden.

     

The preparation and structure of (divinylcyclohexene)nickel—phosphine complexes

Butadiene reacts with (hexatriene)nickel—phosphine complexes to give (divinylcyclohexene)nickel derivatives; the structure of the product from the reaction involving octatriene has been determined crystallographically.     

Design,Synthesis, and Phenotypic Profiling of Pyrano‐Furo‐Pyridone Pseudo Natural Products

Natural products (NPs) inspire the design and synthesis of novel biologically relevant chemical matter, for instance through biology‐oriented synthesis (BIOS). However, BIOS is limited by the partial coverage of NP‐like chemical space by the guiding NPs. The design and synthesis of “pseudo NPs” overcomes these limitations by combining NP‐inspired strategies with fragment‐based compound design through de novo combination of NP‐derived fragments to unprecedented compound classes not accessible through biosynthesis. We describe the development and biological evaluation of pyrano‐furo‐pyridone (PFP) pseudo NPs, which combine pyridone‐ and dihydropyran NP fragments in three isomeric arrangements. Cheminformatic analysis indicates that the PFPs reside in an area of NP‐like chemical space not covered by existing NPs but rather by drugs and related compounds. Phenotypic profiling in a target‐agnostic “cell painting” assay revealed that PFPs induce formation of reactive oxygen species and are structurally novel inhibitors of mitochondrial complex I.     

Dynamik von verankerten meerestechnischen Konstruktionen

The dynamical behaviour of moored structures in ocean engineering in an irregular sea is usually investigated by means of simplified mathematical models. Nonlinear phenomena like the influence of the motion on the mooring geometry or the fluid‐structure interaction are not considered. In this paper a method is described for analyzing the dynamical behaviour of mooring systems including the hydrodynamic forces due to the fluid surrounding the structure. The model for the dynamic analysis is generated using the multibody system method.     

On translation planes of orderq 2 that admit a group of orderq 2 (q−1); bartolone's theorem

This article is concerned with translation planesP of orderq ² and kernelK isomorphic toG F(q). IfP admits a collineation groupG in the linear translation. complement and the order ofG K/K isq ²(q?1) then it is shown thatP is either a semifield plane or is a Lüneburg-Tits, Walker or Betten plane. This generalizes earlier work of Bartolone.