Systemische Beratung in kooperativen Softwareprojekten

Eingegangen am 29.07.1996, in überarbeiteter Form am 11.12.1996     

Optimization and simplification of polymer–fullerene solar cells through polymer and active layer design

Polymer–fullerene bulk heterojunction (BHJ) solar cells have consistently been at the forefront of the growing field of organic photovoltaics (OPV). The enduring vision of OPV is the promise of combining a simple, low-cost approach with an efficient, flexible, lightweight platform. While efficiencies have improved remarkably over the last decade through advances in device design, mechanistic understanding, and evolving chemical structural motifs, steps forward have often been tied to a loss of simplicity and a deviation from the central vision of OPV. Within the context of active layer optimization, our focus is to target high efficiency while maintaining simplicity in polymer design and active layer processing. To highlight this strategy, this feature article focuses on our work on random poly(3-hexylthiophene) (P3HT) analogs and their application in binary and ternary blend polymer–fullerene solar cells. These random conjugated polymers are conceptually based on combining simple monomers strategically to influence polymer properties as opposed to the synthesis of highly tailored and synthetically complex monomers. The ternary blend approach further exemplifies the focus on device simplicity by targeting efficiencies that are competitive with complex tandem solar cells, but within the confines of a single active-layer processing step. These research directions are described within the broader context of recent progress in the field of polymer–fullerene BHJ solar cells.     

Urinary metabolic profiles of inflammatory bowel disease in interleukin-10 gene-deficient mice

Inflammatory bowel disease (IBD) is a chronic debilitating disorder that is thought to have both genetic and environmental contributors. Commensal microflora have been shown to play a key part in the disease process. Metabolomics, the study of large numbers of small molecule metabolites, has demonstrated that disease and/or changes in gut microbial composition modulate mammalian urine metabolite fingerprints. The aim of this project was to associate the development of IBD with specific changes in a mouse urinary metabolic fingerprint. Interleukin-10 (IL-10) gene-deficient mice were raised alongside age-matched 129/SvEv controls in conventional housing. Urine samples (22 h) were collected at ages 4, 6, 8, 12, 16, and 20 weeks. Metabolite concentrations were derived from analysis of nuclear magnetic resonance spectra, and both multivariate and two-way analysis of variance (ANOVA) statistical techniques were applied to the resulting data. Principal component analysis and partial least-squares-discriminant analysis of urine derived from the control and IL-10 gene-deficient mice revealed that while both groups initially had similar metabolic profiles, they diverged substantially with the onset of IBD as assessed through external phenotypic changes. Several metabolites, including trimethylamine (TMA) and fucose, changed dramatically in the IL-10 gene-deficient mice following 8 weeks of age, concomitant with the known timeline for development of severe histological injury. This study illustrates that metabolomics is effective at distinguishing IBD using urinary metabolite profiles.     

How metal ions affect amyloid formation: Cu2+- and Zn2+-sensitive peptides

The common feature of proteins involved in many neurodegenerative diseases is their ability to adopt at least two different stable conformations. The conformational transition that shifts the equilibrium from the functional, mostly partially alpha-helical structure, to the beta-sheet rich amyloid can be triggered by numerous factors, such as mutations in the primary structure or changes in the environment. We present a set of model peptides that, without changes in their primary structure, react in a predictable fashion in the presence of transition metal ions by adopting different conformations and aggregate morphologies. These de novo designed peptides strictly follow the characteristic heptad repeat of the alpha-helical coiled-coil structural motif. Furthermore, domains that favor beta-sheet formation have been incorporated to make the system prone to amyloid formation. As a third feature, histidine residues create sensitivity towards the presence of transition metal ions. CD spectroscopy, ThT fluorescence experiments, and transmission electron microscopy were used to characterize peptide conformation and aggregate morphology in the presence of Cu2+ and Zn2+. Furthermore, the binding geometry within peptide-Cu2+ complexes was characterized by electron paramagnetic resonance spectroscopy.     

The molecular detection of relaxin and its receptor RXFP1 in reproductive tissue of Felis catus and Lynx pardinus during pregnancy

Relaxin acts as a pregnancy-specific signal in feline species, but specific information about protein structure and binding is essential for the improvement of pregnancy diagnosis in endangered feline species, like the Iberian lynx. To generate a felid-specific relaxin antibody, the DNA and protein sequences of lynx and cat were determined and peptides were chosen for antibody generation. In addition, relaxin and relaxin receptor (RXFP1) mRNA expressions were measured in uteri and ovaries of pregnant domestic cats and lynx placentae. Using real-time PCR and immunohistochemistry, it was established that feline placenta is the main source of relaxin during pregnancy. In other tested tissues, relaxin mRNA expression was weak. The RXFP1 mRNA expression was found mainly in cat uterine tissue and feline placentae. It was assumed that these tissues were main targets for relaxin. In the ovary, relaxin immunostaining was associated with blood vessels, signifying its role in vascularization.     

Stahlleichtbau mit Verbundelementen

Der folgende Beitrag gibt einen Überblick über den Stahlleichtbau mit Verbundelementen. Im Vordergrund stehen hierbei Bauteile mit Blechdicken < 3 mm, die im Verbund mit OSB‐ oder Gipskartonplatten wirken. Durch die Verbundwirkung ergeben sich nennenswerte Verbesserungen der Tragfähigkeit und der Gebrauchstauglichkeit sowie der bauphysikalischen Eigenschaften. Weiterhin werden Sandwichelemente behandelt. Lightweight steel construction with composite elements. This paper contains an overview of lightweight steel structures acting compositely with other materials. Primarily members with wall thicknesses below 3 mm are covered. They act together with OSB‐ or gypsum‐boards. This leads to a significant improvement of the ultimate load as well as of the serviceability and building physics aspects. Furthermore sandwich panels are discussed.     

Influence of the adhesive layer on the mechanical properties of thin veneer-based composite materials

For the production of spliced veneers the veneers are coated with thin cellulose fleece or special paper layers, and thereby thin composites are generated. This article describes the mechanical properties of such a composite material consisting of 0.35 mm beech (Fagus sylvatica  L.) veneer and a 0.12 mm cellulose fleece bonded with a PVAc adhesive.