Membrane Trafficking of Death Receptors: Implications on Signalling

Death receptors were initially recognised as potent inducers of apoptotic cell death and soon ambitious attempts were made to exploit selective ignition of controlled cellular suicide as therapeutic strategy in malignant diseases. However, the complexity of death receptor signalling has increased substantially during recent years. Beyond activation of the apoptotic cascade, involvement in a variety of cellular processes including inflammation, proliferation and immune response was recognised. Mechanistically, these findings raised the question how multipurpose receptors can ensure selective activation of a particular pathway. A growing body of evidence points to an elegant spatiotemporal regulation of composition and assembly of the receptor-associated signalling complex. Upon ligand binding, receptor recruitment in specialized membrane compartments, formation of receptor-ligand clusters and internalisation processes constitute key regulatory elements. In this review, we will summarise the current concepts of death receptor trafficking and its implications on receptor-associated signalling events.     

Flame Retardancy Mechanisms of Aluminium Phosphinate in Combination with Melamine Cyanurate in Glass‐Fibre‐Reinforced Poly(1,4‐butylene terephthalate)

The flame retardancy mechanisms of aluminium diethylphosphinate (AlPi) and its combination with melamine cyanurate (MC) in glass‐fibre‐reinforced poly(butylene terephthalate) (PBT/GF) were analysed using TGA including evolved gas analysis (TGA‐FTIR), cone calorimeter measurements using various irradiations, flammability tests (limited oxygen index, LOI, UL 94) and chemical analyses of residues (FTIR, SEM/EDX). AlPi decomposed mainly through the formation of diethylphosphinic acid and aluminium phosphate and influenced the decomposition of the PBT only slightly. AlPi acted mainly through flame inhibition. A halogen‐free V‐0 PBT/GF material was achieved with a LOI of 44%. Additional charring influenced the flammability. MC decomposed independently of the polymer and showed some fuel dilution effects.

     

An enzyme module system for the synthesis of dTDP-activated deoxysugars from dTMP and sucrose

A flexible enzyme module system is presented that allows preparative access to important dTDP-activated deoxyhexoses from dTMP and sucrose. The strategic combination of the recombinant enzymes dTMP-kinase and sucrose synthase (SuSy), and the enzymes RmlB (4,6-dehydratase), RmlC (3,5-epimerase) and RmlD (4-ketoreductase) from the biosynthetic pathway of dTDP-beta-L-rhamnose was optimized. The SuSy module (dTMP-kinase, SuSy, +/-RmlB) yielded the precursor dTDP-alpha-D-glucose (2) or the biosynthetic intermediate dTDP-6-deoxy-4-keto-alpha-D-glucose (3) on a 0.2-0.6 g scale with overall yields of 62 % and 72 %, respectively. A two-step strategy in which the SuSy module was followed by the deoxysugar module (RmlC and RmlD) resulted in the synthesis of dTDP-beta-L-rhamnose (4; 24.1 micromol, overall yield: 35.9 %). Substitution of RmlC by DnmU from the dTDP-beta-L-daunosamine pathway of Streptomyces peucetius in this module demonstrated that DnmU acts in vitro as a 3,5-epimerase with 3 as substrate to yield 4 (32.2 mumol, overall yield: 44.7 %). Chemical reduction of 3 with NaBH4 gave a mixture of the C-4 epimers dTDP-alpha-D-quinovose (6) and dTDP-alpha-D-fucose (7) in a ratio of 2:1. In summary, the modular character of the presented enzyme system provides valuable compounds for the biochemical characterization of deoxysugar pathways playing a major role in microbial producers of antibiotic and antitumour agents.     

The impact of water released from boehmite nanoparticles during curing in epoxy-based nanocomposites

The enhancing effect on mechanical properties of boehmite (γ-AlOOH) nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro- and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action. With FTIR-spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail. The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (T_g) and an interphase formation.     

Eigenschaften von Gießfilmen aus nativen und chemisch modifizierten Stärken

Properties of Casting Films from Native and Chemically Modified Starches. Starch acetates and hexanoates were prepared from potato, wrinkled pea, and amylomaize starch of low and high degrees of substitution (DS=0.1-2.8). These products were used as raw materials for film casting in a laboratory scale. The objective of this work was to study the influence of starch types and derivatisations on film properties, i.e. tensile strength and elongation as well as water absorption and solubility. After the addition of softeners transparent, flexible, and water soluble films were obtained from unsubstituted and partially substituted starches, while totally substituted starch derivatives (triacetates and hexanoates) resulted in films insoluble in water. The well-known amylose advantage of film casting was found only after derivatisation. In the case of wrinkled pea and amylomaize starch considerable improvements of mechanical film properties, both tensile strength and elongation, were achieved even at low degrees of substitution.     

A Tensor-based Regression Approach for Human Motion Prediction

Collaborative robotic systems will be a key enabling technology for current and future industrial applications. The main aspect of such applications is to guarantee safety for humans. To detect hazardous situations, current commercially available robotic systems rely on direct physical contact to the co-working person. To further advance this technology, there are multiple efforts to develop predictive capabilities for such systems. Using motion tracking sensors and pose estimation systems combined with adequate predictive models, potential episodes of hazardous collisions between humans and robots can be predicted. Based on the provided predictive information, the robotic system can avoid physical contact by adjusting speed or position. A potential approach for such systems is to perform human motion prediction with machine learning methods like artificial neural networks (NNs). In our approach, the motion patterns of past seconds are used to predict future ones by applying a linear Tensor-on-Tensor Regression model, selected according to a similarity measure between motion sequences obtained by dynamic time warping (DTW). For test and validation of our proposed approach, industrial pseudo assembly tasks were recorded with a motion capture system, providing unique traceable Cartesian coordinates $(x,y,z)$ for each human joint. The prediction of repetitive human motions associated with assembly tasks, whose data vary significantly in length and have highly correlated variables, has been achieved in real time.     

X-Ray Tomoscopy Reveals the Dynamics of Ice Templating

Little experimentally explored and understood are the complex dynamics of microstructure formation by ice-templating when aqueous solutions or slurries are directionally solidified (freeze cast) into cellular solids. With synchrotron-based, time-resolved X-ray tomoscopy it is possible to study in situ under well-defined conditions the anisotropic, partially faceted growth of ice crystals in aqueous systems. Obtaining one full tomogram per second for ≈270 s with a spatial resolution of 6 µm, it is possible to capture with minimal X-ray absorption, the freezing front in a 3% weight/volume (w/v) sucrose-in-water solution, which typically progresses at 5–30 µm s⁻¹ for applied cooling rates of $\dot{C}$ = 1–10 °C min⁻¹. These time and length scales render X-ray tomoscopy ideally suited to quantify in 3D ice crystal growth and templating phenomena that determine the performance-defining hierarchical architecture of freeze-cast materials: a complex pore morphology and “ridges”, “jellyfish cap”, and “tentacle”-like secondary features, which decorate the cell walls.