Cell Force-Driven Basement Membrane Disruption Fuels EGF- and Stiffness-Induced Invasive Cell Dissemination from Benign Breast Gland Acini

Local basement membrane (BM) disruption marks the initial step of breast cancer invasion. The activation mechanisms of force-driven BM-weakening remain elusive. We studied the mechanical response of MCF10A-derived human breast cell acini with BMs of tuneable maturation to physical and soluble tumour-like extracellular matrix (ECM) cues. Traction force microscopy (TFM) and elastic resonator interference stress microscopy (ERISM) were used to quantify pro-invasive BM stress and protrusive forces. Substrate stiffening and mechanically impaired BM scaffolds induced the invasive transition of benign acini synergistically. Robust BM scaffolds attenuated this invasive response. Additional oncogenic EGFR activation compromised the BMs’ barrier function, fuelling invasion speed and incidence. Mechanistically, EGFR-PI3-Kinase downstream signalling modulated both MMP- and force-driven BM-weakening processes. We show that breast acini form non-proteolytic and BM-piercing filopodia for continuous matrix mechanosensation, which significantly push and pull on the BM and ECM under pro-invasive conditions. Invasion-triggered acini further shear and compress their BM by contractility-based stresses that were significantly increased (3.7-fold) compared to non-invasive conditions. Overall, the highest amplitudes of protrusive and contractile forces accompanied the highest invasiveness. This work provides a mechanistic concept for tumour ECM-induced mechanically misbalanced breast glands fuelling force-driven BM disruption. Finally, this could facilitate early cell dissemination from pre-invasive lesions to metastasize eventually.     

Parallelwelten – Informelle Arbeit in der Abfallwirtschaft

Rapid urbanization, increasing amounts of waste, and municipalities lacking in both financial and personal resources are characteristic of waste management in low-income countries. “Formal” waste management, represented by national and regional authorities and private companies, is not in a position to provide adequate waste collection and treatment for the local population. Burning waste in backyard fires or tossing it in roadside ditches or “wild dumps” are common practices. But in addition to the formal system, which is unable to cope with the current situation, there is a parallel and informal system that closes the gaps in the collection, processing, treatment and disposal of waste. Informal activities in waste management have become increasingly important in implementation projects and science in recent years. As informal workers are, by definition, not keeping records of their activities, their contribution is not recognized, and the workers remain invisible. The important contribution of the informal sector should not be underestimated, as a major share of waste recycling activities are carried out informally, providing secondary raw materials to local markets. In many cases the informal workers are not recognized as having a key role in waste management systems and run the risk of losing their livelihoods thanks to modernization processes. Informal sector activities take place not only in low-income countries but also in Central and Eastern European countries. However, these activities are carried out against the backdrop of a functioning waste management system and on a legal basis.     

Surface characterization of flax,hemp and cellulose fibers; Surface properties and the water uptake behavior

The surface characteristics of several natural fibers—flax, hemp and cellulose—were investigated using scanning electron microscopy, BET-surface area and zeta (ζ-) potential measurements. ζ-Potential measurements using the streaming potential method were performed in order to study the water uptake behavior as well as the surface properties of several natural fibers. The influence of different flax-fiber separation methods and several modifications, like industrial purification, and such a treatment followed by alkaline purification as well as polypropylene grafting on the fiber surface morphology, surface area and time- and pH-depending ζ-potentials were studied. The time-dependence of the ζ-potential, measured in 1 mM KCl solution, offeres and alternative possibility to estimate the water uptake behavior for nearly all investigated natural fibers. The water uptake data derived from the ζ-potential measurements (ζ = f(t)) were compared with data from conventional water adsorption studies for some chosen examples.     

Suitability of Modified Supercritical Carbon Dioxide as Solvent for polar substances

As solvent supercritical carbon dioxide offers unique possibilities, like non-toxicity and therefore reduction of environmental pollution or access of low-temperature processing resulting in additional process safety. Therefore, knowledge to the influence of modifiers due to better solubility of polar substances is important for evaluating novel manufacturing techniques like the RESS- or GAS-process. Dynamic supercritical fluid extraction of PETN, nitroguanidine (NIGU) and RDX, respectively, with pure as well as with modified carbon dioxide indicated that all explosives except nitroguanidine were extracted though for RDX and 3-nitro-1,2,4-triazole the use of modifiers proved to be necessary. The results show the high capacity of modified supercritical carbon dioxide as a solvent in RESS- and GAS-processes.     

Characteristic Properties of an End Burning Grain with Smoke Reduced Ferrocene Containing Composite Propellant

Design, formulation and properties of an end burning grain are described which works for underwater propulsion operating at the level of 1200 N thrust for 20 s burning time. To avoid cavitational noise the formation of hot particles must be prevented. For this reason a smoke reduced composite propellant based on AP/HTPB with 86% energetic solids including 14% HMX and with 1% ferrocene derivative was adapted to grain size and motor configuration. For inhibition a pyrolytically stabilized polyurethane insulation was applied. The thermal insulation was made from a stiff high temperature resistant phenolic resin. The propellant exhibited a smooth burning behaviour with good processibility and mechanical properties. The desired performance was delivered at 120 bar operating pressure connected to 165 mm grain diameter and 93% thrust efficiency. Looking closer to the system it was found that part of the ferrocene derivative and plasticizer migrated from the propellant block to the inhibition layer. In the course of migration a small change of burning but a larger change of mechanical properties occurred in the boundary of the propellant. Despite these disadvantages burning times of 5 s and 10 s had been successfully realized with a case bonded configuration. For larger grain sizes, however, cracks occurred around the surface of the cylindrical propellant block. Calculation of the mechanical stresses which built up upon thermal shrinkage after curing and cooling showed values higher than the mechanical strength of the propellant could fit. These problems finally were overcome by a free standing grain. It led to a successful function of the motor for burning times of 20 s and more.