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Bochum-Hordel, Germany

Dullmann J.,Ruhr University Bochum | Dullmann J.,Universitatsstrasse 150 | Alber M.,Ruhr University Bochum | Plinninger R.J.,PG Dr. Plinninger Geotechnik
Geomechanik und Tunnelbau | Year: 2014

The evaluation of the abrasiveness of soil is not unified or standardised at the moment. Mostly used are complex index processes with greatly simplified model bodies and simplified test conditions such as the LCPC abrasimeter test. These processes can however at best measure the efficiency of the wear mechanism and are not capable of reflecting the strength of the bonding of the internal fabric, an essential factor determining the level of operational demands, i.e. the resistance to excavation. These index processes therefore offer no advantages over evaluation processes based on conventional soil mechanics parameters. Quite the opposite, these mostly prototype tests imply new problems that are inevitable with the testing methods. The paper thus presents at the end an extended method of evaluating wear to excavation tools and the conveyance or transport of excavated spoil. © 2014 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Beste C.,Ruhr University Bochum | Dinse H.R.,Universitatsstrasse 150
Current Biology | Year: 2013

Achieving high-level skills is generally considered to require intense training, which is thought to optimally engage neuronal plasticity mechanisms. Recent work, however, suggests that intensive training may not be necessary for skill learning. Skills can be effectively acquired by a complementary approach in which the learning occurs in response to mere exposure to repetitive sensory stimulation. Such training-independent sensory learning induces lasting changes in perception and goal-directed behaviour in humans, without any explicit task training. We suggest that the effectiveness of this form of learning in different sensory domains stems from the fact that the stimulation protocols used are optimized to alter synaptic transmission and efficacy. While this approach directly links behavioural research in humans with studies on cellular plasticity, other approaches show that learning can occur even in the absence of an actual stimulus. These include learning through imagery or feedback-induced cortical activation, resulting in learning without task training. All these approaches challenge our understanding of the mechanisms that mediate learning. Apparently, humans can learn under conditions thought to be impossible a few years ago. Although the underlying mechanisms are far from being understood, training-independent sensory learning opens novel possibilities for applications aimed at augmenting human cognition. © 2013 Elsevier Ltd. Source

Hussong J.,Universitatsstrasse 150 | Lindken R.,ZBT GmbH | Faulhammer P.,Justus Liebig University | Noreikat K.,University of Leipzig | And 3 more authors.
Journal of Biomechanics | Year: 2013

To date, there is only a fragmentary understanding of the fundamental mechanisms of airway mucociliary transport. Application of the latest measurement techniques can aid in deciphering the complex interplay between ciliary beat and airway surface liquid (ASL) transport. In the present study, direct, quasi-simultaneous measurements of the cilia-induced fluid and bead transport were performed to gain a better insight into both transport mechanisms. In this study cilia-induced periciliary liquid (PCL) transport is measured by means of micro Particle Image Velocimetry (μPIV) with neutrally buoyant tracers. Particle Tracking Velocimetry (PTV) with heavier polystyrene-ferrite beads is performed to simulate particle transport. Contrary to recent literature, in which the presence of mucus was deemed necessary to maintain periciliary liquid (PCL) transport, effective particle and fluid transport was measured in our experiments in the absence of mucus. In response to muscarine or ATP stimulation, maximum fluid transport rates of 250 μm/s at 15 μm distance to the tracheal epithelia were measured while bead transport rates over the epithelia surfaces reached 200 μm/s. We estimated that the mean bead transport is dominated by viscous drag compared to inertial fluid forces. Furthermore, mean bead transport velocities appear to be two orders of magnitude larger compared to bead sedimentation velocities. Therefore, beads are expected to closely follow the mean PCL flow in non-ciliated epithelium regions. Based on our results, we have shown that PCL transport can be directly driven by the cilia beat and that the PCL motion may be capable of driving bead transport by fluid drag. © 2012. Source

Peters M.,Ruhr University Bochum | Kohler-Bachmann S.,Ruhr University Bochum | Lenz-Habijan T.,Universitatsstrasse 150 | Bufe A.,Ruhr University Bochum
American Journal of Respiratory Cell and Molecular Biology | Year: 2016

We showed previously that sensitization of mice with dendritic cells (DCs) via the airways depends on activation of these cells with LPS. Allergen-pulsedDCs that were stimulated with lowdoses of LPS induce a strong Th2 response in vivo. Our objective was to investigate whether airway sensitization ofmice by the application ofDCs with a phenotype that is able to induce Th17 cells results in increased remodeling of the airways.We generated DCs fromthe bone marrow ofmice and pulsed them with LPS-free ovalbumin. Subsequently, cells were activated with LPS with or without ATP for inflammasome activation. The activated cellswere used to sensitizemice via the airways. Intranasal instillation of DCs thatwere activated with 0.1ng/ml LPS induced aTh2 response with airway eosinophilia. High doses of LPS, particularly when given in combinationwithATP, led to induction of a mixed Th2/Th17 response. Interestingly, we found a correlation between IL-17A production and the remodeling of the airways. Stimulation ofmouse fibroblasts with purified IL-17A protein in vitro resulted in transforming growth factor-b1 secretion and collagen transcription. Interestingly, we found enhanced secretion of transforming growth factor-b1 by fibroblasts after costimulation with IL-17A and the profibrotic factor winglesstype MMTV integration site family, member 5A (Wnt5a). We showed that an allergen-specific Th17 response in the airway is accompanied by increased airway remodeling. Furthermore, we revealed that increased remodeling is not only based on neutrophilic inflammation, but also on the direct impact of IL-17A on airway structural cells. Copyright © 2016 by the American Thoracic Society. Source

Morawietz T.,Universitatsstrasse 150 | Behler J.,Universitatsstrasse 150
Zeitschrift fur Physikalische Chemie | Year: 2013

Water clusters have attracted a lot of attention as prototype systems to study hydrogen bonded molecular aggregates but also to gain deeper insights into the properties of liquid water, the solvent of life. All these studies depend on an accurate description of the atomic interactions and countless potentials have been proposed in the literature in the past decades to represent the potential-energy surface (PES) of water. Many of these potentials employ drastic approximations like rigid water monomers and fixed point charges, while on the other hand also several attempts have been made to derive very accurate PESs by fitting data obtained in high-level electronic structure calculations. In recent years artificial neural networks (NNs) have been established as a powerful tool to construct high-dimensional PESs of a variety of systems, but to date no full-dimensional NN PES for water has been reported. Here, we present NN potentials for water clusters containing two to six water molecules trained to density functional theory (DFT) data employing two different exchange-correlation functionals, PBE and RPBE. In contrast to other potentials fitted to first principles data, these NN potentials are not based on a truncated many-body expansion of the energy but consider the interactions between all water molecules explicitly. For both functionals an excellent agreement with the underlying DFT calculations has been found with binding energy errors of only about 1%.© by Oldenbourg Wissenschaftsverlag, München. Source

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