Dynamic architecture of the peroxisomal import receptor Pex5p

AbstractThe majority of peroxisomal matrix proteins are recognized by the import receptor Pex5p. The receptor is dynamic in terms of its overall architecture and association with the peroxisomal membrane. It participates in different protein complexes during the translocation of cargos from the cytosol to the peroxisomal matrix. Its sequence comprises two structurally and functionally autonomous parts. The N-terminal segment interacts with several peroxins that assemble into distinct protein complexes during cargo translocation. Despite evidence for α-helical binding motifs for some of these components (Pex13p, Pex14p) its overall appearance is that of a molten globule and folding/unfolding transitions may play a critical role in its function. In contrast, most of the C-terminal part of the receptor folds into a ring-like α-helical structure and binds folded and functionally intact peroxisomal targets that bear a C-terminal peroxisomal targeting signal type-1. Some of these targets also bind to secondary binding sites of the receptor

Ultrakurzpulsinduzierte Brechzahlmodifikationen in transparenten Festkörpern

Eine neue Möglichkeit lokale Veränderung im Materialvolumen hervorzurufen, bietet die Anwendung nichtlinearer Absorptionsprozesse bei der Wechselwirkung von ultrakurzen Laserpulsen mit transparenten Materialien. Zur Erzeugung von 3D-Mikrostrukturen wird Ultrakurzpluslaserstrahlung in das Material fokussiert. Über die Wahl der Energieparameter ist es möglich nur im konfokalen Bereich die Absorptionsschwelle zu übertreffen und durch die Energiedeposition lokale Materialmodifikationen zu erzeugen. Die Untersuchung dieses Prozesses ist Gegenstand der vorliegenden Arbeit

The effect of skin passing on the material behavior of metal strip in pure bending and tension

The metal strip used in roll forming has often been preprocessed by (tension or roller) leveling or by skin-pass rolling, and as a consequence, may contain residual stresses. These stresses are not well observed by the tensile test, but could have a significant effect on the bending and springback behavior. With the advent of improved process design techniques for roll forming, including advanced finite element techniques, the need for precise material property data has become important. The major deformation mode of roll forming is that of bending combined with unloading and reverse bending, and hence property data derived from bend tests could be more relevant than that from tensile testing. This work presents a numerical study on the effect of skin passing on the material behavior of stainless steel strip in pure bending and tension. A two dimensional (2-D) numerical model was developed using Abaqus Explicit to analyze the affect of skin passing on the residual stress profile across a section for various working conditions. The deformed meshes and their final stress fields were then imported as pre-defined fields into Abaqus Standard, and the post-skin passing material behavior in pure bending was determined. The results show that a residual stress profile is introduced into the steel strip during skin passing, and that its shape and stress level depend on the overall thickness reduction as well as the number of rolling passes used in the skin passing process. The material behavior in bending and the amount of springback changed significantly depending on the skin pass condition

Chemical composition of field grown radish (Raphanus sativus L. var. sativus) as influenced by season and moderately reduced water supply

Seasonal variations in water availability as increasingly provoked by climate change pose severe challenges for vegetable production, particularly for crops requiring reliable and high water supply for achieving satisfactory quality. In contrast to most previous studies applying severe water deficits, we examined the effects of moderate water deficits on the chemical composition of red radish roots during three consecutive years with variable climatic conditions. Radish were cultivated in open field, applying two different water supply treatments and following a randomized block design comprising four sets of six plots each. The resulting water reductions of 3-20 % led to a significant increase of dry matter-based myo-inositol levels, whereas those of selected minerals and trace elements, phenolics and glucosinolates decreased. Anthocyanin levels remained unchanged. Fresh-matter related levels of most analytes increased upon reduced water treatments due to higher dry matter contents. While pigment levels in radish remained unchanged, mild water deficit affected other quality-related parameters such as pungency-related glucosinolates

Two-phase SLIPI for instantaneous LIF and Mie imaging of transient fuel sprays

We report in this Letter a two-phase structured laser illumination planar imaging [two-pulse SLIPI (2p-SLIPI)] optical setup where the "lines structure" is spatially shifted by exploiting the birefringence property of a calcite crystal. By using this optical component and two cross-polarized laser pulses, the shift of the modulated pattern is not "time-limited" anymore. Consequently, two sub-images with spatially mismatched phases can be recorded within a few hundred of nanoseconds only, freezing the motion of the illuminated transient flow. In comparison with previous setups for instantaneous imaging based on structured illumination, the current optical design presents the advantage of having a single optical path, greatly simplifying its complexity. Due to its virtue of suppressing the effects from multiple light scattering, the 2p-SLIPI technique is applied here in an optically dense multi-jet direct-injection spark-ignition (DISI) ethanol spray. The fast formation of polydispersed droplets and appearance of voids after fuel injection are investigated by simultaneous detection of Mie scattering and liquid laser-induced fluorescence. The results allow for significantly improved analysis of the spray structure