Catalytic C-C bond formation accomplished by selective C-F activation of perfluorinated arenes

The first example of a catalytically active system for Suzuki-type cross-coupling reactions of perfluorinated arenes such as octafluorotoluene and decafluorobiphenyl is presented.     

Rubber Powder – A Perspective Filler of Thermoplastics

Rubber powder, ground at ambient temperature, was compounded with polypropylene using only 16 L/D of a co-rotating twin screw extruder. An optimum of extruder configuration and selected process parameters were found for compounds with a rubber filling rate of 50 wt.-%. Restrictions of a reactive compounding were taken into account. The dispersion of the rubber powder is not a limiting process. A compound containing 70 wt.-% rubber powder showed to be overfilled.     

Control of dark current in photoelectrochemical (TiO2/I--I3-)) and dye-sensitized solar cells

The ruthenium complex bis-tetrabutylammonium cis-dithiocyanato-N,N'-bis-2,2'-bipyridine-4-carboxylic acid, 4'-carboxylate ruthenium(II), N-719, was found to block the dark current of dye sensitized solar cells (DSC), based on mesoporous TiO2 films deposited on a F-doped tin oxide electrode and the effect was compared to surface treatment by TiCl4 and the introduction of a compact TiO2 blocking layer.     

Analytical separation techniques for the determination of chemical warfare agents

Today, the determination of chemical warfare agents (CWAs) is an important area of application in analytical chemistry. Chromatographic, capillary electrophoretic and mass spectrometric techniques are primarily used for the identification and quantification of a broad field of classical CWAs in environmental samples and neutralization masses, obtained after destruction of CWAs. This overview is illustrative for the state of the art and mainly focuses on the literature published since 1996.     

On the rank of truncated incidence matrices of linear spaces

It is well known that for every finite linear space the number b of lines is greater or equal to the number v of points of the space. In this paper we investigate the relation between the nonnegative integer b - v and suitable configurations of subspaces of a linear space.     

Pulling tethers from adhered vesicles

The competition between adhesion and tether formation in bound vesicles is investigated. A theoretical model is developed in which tethers are induced by the application of a pulling force to the top of a strongly adhered vesicle. A critical onset force is identified where the tether spontaneously appears as part of a first order shape transition. Further growth of the tether initiates a detachment process that culminates in a continuous unbinding of the vesicle at a finite detachment force. Both critical forces, as well as all shape parameters, are calculated as a function of the reduced volume and the strength of adhesive potential.     

Characterization of lipids in complex samples using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry

Most lipids are a complex mixture of classes of compounds such as fatty acids, fatty alcohols, diols, sterols and hydroxy acids. In this study, the suitability of comprehensive two-dimensional gas chromatography coupled to a time-of-light mass spectrometer is studied for lipid characterization in complex samples. With lanolin, a refined wool wax, as test sample, it is demonstrated that combined methylation plus silylation is the preferred derivatization procedure to achieve (i) high-quality GC x GC separation and (ii) easily recognizable ordered structures in lipid analysis. Optimization of the GC x GC column combination, the influence of the temperature programme on the quality of the separation, and the potential and limitations of automated TOF-MS-based identification are discussed. The combined power of a 2D separation, ordered structures and MS detection is illustrated by the identification of several minor sample constituents.