Semisynthetic murine prion protein equipped with a GPI anchor mimic incorporates into cellular membranes

Conversion of cellular prion protein (PrP(C)) into the pathological conformer (PrP(Sc)) has been studied extensively by using recombinantly expressed PrP (rPrP). However, due to inherent difficulties of expressing and purifying posttranslationally modified rPrP variants, only a limited amount of data is available for membrane-associated PrP and its behavior in vitro and in vivo. Here, we present an alternative route to access lipidated mouse rPrP (rPrP(Palm)) via two semisynthetic strategies. These rPrP variants studied by a variety of in vitro methods exhibited a high affinity for liposomes and a lower tendency for aggregation than rPrP. In vivo studies demonstrated that double-lipidated rPrP is efficiently taken up into the membranes of mouse neuronal and human epithelial kidney cells. These latter results enable experiments on the cellular level to elucidate the mechanism and site of PrP-PrP(Sc) conversion.     

The nonstationary transition through resonance

This paper considers the resonant behavior of a mechanical oscillator during a linear frequency sweep. Both numerical and experimental results are presented. The experimental system consisting of a track in the shape of a potential energy surfaces has been used to highlight other types of nonlinear behavior and is here adapted so that the forcing frequency can be evolved continuously in time. The classic linear oscillator (with a parabolic potential well) is used as an introduction to illustrate basic features of the experiment and its response. Then, a track with a double well is used to assess nonstationary frequency effects on certain nonlinear characteristics, specifically amplitude jumps and flip bifurcations.     

Die Gegenstromverteilung der Methylester h?herer Fetts?uren

Ohne Zusammenfassung     

Zur Bestimmung der Acetylene in Butadien

Ohne Zusammenfassung     

Polarizing and non-polarizing mirrors for the hydrogen Lyman-<Emphasis Type="Italic">α</Emphasis> radiation at 121.6 nm

Efficient polarizing as well as non-polarizing mirrors for a wavelength of λ=121.6 nm (hydrogen Lyman-α radiation) are necessary to achieve an experimental determination of the magnetic field in the solar corona through the Hanle effect. We have designed, realized and characterized such mirrors. These consist of glass coated with a thin-film stack. The coatings use the most reflective (Al) and most transparent (fluorides) materials at this wavelength. Different coatings were explored which involve an increasing number of films in the coating stack. At the incident angle of maximum polarization where the p-polarized reflectivity R _p is minimized, an s-polarized reflectivity R _s as high as 69% is experimentally obtained with a coating made of a Fabry–Pérot resonator. To our knowledge, this value is the highest ever reported for a polarizing mirror at this wavelength. Additionally, efficient non-polarizing mirrors have been designed and realized by using a two-layer coating (MgF₂/Al/glass). By optimizing the fluoride layer thickness, a mirror with non-polarizing properties in the whole range of incident angles was realized.