TechnischeUniversitat Dresden

Dresden, Germany

TechnischeUniversitat Dresden

Dresden, Germany
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Wehner D.,University of Edinburgh | Tsarouchas T.M.,University of Edinburgh | Michael A.,University of Edinburgh | Haase C.,TechnischeUniversitat Dresden | And 4 more authors.
Nature Communications | Year: 2017

The inhibitory extracellular matrix in a spinal lesion site is a major impediment to axonal regeneration in mammals. In contrast, the extracellular matrix in zebrafish allows substantial axon re-growth, leading to recovery of movement. However, little is known about regulation and composition of the growth-promoting extracellular matrix. Here we demonstrate that activity of the Wnt/β-catenin pathway in fibroblast-like cells in the lesion site is pivotal for axon re-growth and functional recovery. Wnt/β-catenin signaling induces expression of col12a1a/b and deposition of Collagen XII, which is necessary for axons to actively navigate the non-neural lesion site environment. Overexpression of col12a1a rescues the effects of Wnt/β-catenin pathway inhibition and is sufficient to accelerate regeneration. We demonstrate that in a vertebrate of high regenerative capacity, Wnt/β-catenin signaling controls the composition of the lesion site extracellular matrix and we identify Collagen XII as a promoter of axonal regeneration. These findings imply that the Wnt/β-catenin pathway and Collagen XII may be targets for extracellular matrix manipulations in non-regenerating species. © 2017 The Author(s).

Vanhellemont J.,Ghent University | Chen J.,Zhejiang University | Chen J.,TechnischeUniversitat Dresden | Lauwaert J.,Ghent University | And 6 more authors.
Journal of Crystal Growth | Year: 2011

During the last decade, the 300 mm silicon wafer has been optimized and one is studying the move to 450 mm crystals and wafers. The ever increasing silicon crystal diameter leads to two important trends with respect to substrate characteristics: the interstitial oxygen concentration decreases while the size of grown in voids and crystal originated particles (COPs) in vacancy-rich crystals is increasing. The first effect is due to the large melt in which movements have to be controlled and partly suppressed by the use of magnetic fields. This magnetic confinement leads to a more uniform dopant incorporation but at the same time to a more limited transport of oxygen from the quartz crucible to the melt and the growing crystal. The reduced interstitial oxygen concentration and the lower thermal budget of modern device processing leads to strongly reduced oxygen precipitation and thus internal gettering capacity. The increasing COP size (accompanied by a decreasing density) is caused by the decreasing pulling rate and thermal gradient that have to be used in order to avoid dislocation formation. The slower cooling of the crystal leads to a decreased void nucleation rate and at the same time to an increased thermal budget for void growth as well as a larger number of vacancies available per void. In the present paper the effect of germanium doping in the range between 1016 and 1019 cm-3 on COP formation and oxygen precipitation is discussed and illustrated. Also the beneficial effect of germanium doping with respect to wafer breakage during processing, with respect to the suppression of thermal donor formation and with respect to improving device radiation hardness is addressed. © 2010 Elsevier B.V. All rights reserved.

Holmes D.,University College London | Holmes D.,Sphere Fluidics | Whyte G.,Friedrich - Alexander - University, Erlangen - Nuremberg | Whyte G.,University of Cambridge | And 7 more authors.
Interface Focus | Year: 2014

Determining cell mechanical properties is increasingly recognized as a marker-free way to characterize and separate biological cells. This emerging realization has led to the development of a plethora of appropriate measurement techniques. Here, we use a fairly novel approach, deterministic lateral displacement (DLD), to separate blood cells based on their mechanical phenotype with high throughput. Human red blood cells were treated chemically to alter their membrane deformability and the effect of this alteration on the hydrodynamic behaviour of the cells in a DLD device was investigated. Cells of defined stiffness (glutaraldehyde cross-linked erythro-cytes) were used to test the performance of the DLD device across a range of cell stiffness and applied shear rates. Optical stretching was used as an independent method for quantifying the variation in stiffness of the cells. Lateral displacement of cells flowing within the device, and their subsequent exit position from the device were shown to correlate with cell stiffness. Data showing how the isolation of leucocytes from whole blood varies with applied shear rate are also presented. The ability to sort leucocyte sub-populations (T-lymphocytes and neutrophils), based on a combination of cell size and deformability, demonstrates the potential for using DLD devices to perform continuous fractionation and/or enrichment of leucocyte sub-populations from whole blood. ©2014 The Authors.

Fantuzzi P.,University of Modena and Reggio Emilia | Fantuzzi P.,CNR Institute of Neuroscience | Martini L.,University of Modena and Reggio Emilia | Martini L.,CNR Institute of Neuroscience | And 10 more authors.
Carbon | Year: 2016

Electrospray deposition (ESD) in ambient conditions has been used to deposit graphene nanoribbons (GNRs) dispersed in liquid phase on different types of substrates, including ones suitable for electrical transport. The deposition process was controlled and optimized by using Raman spectroscopy, Scanning Probe Microscopies and Scanning Electron Microscopy. When deposited on graphitic electrodes, GNRs were used as semi-conducting channel in three terminal devices showing gate tunability of the electrical current. These results suggest that ESD technique can be used as an effective tool to deposit chemically synthesized GNRs onto substrates of interest for technological applications. © 2016 Elsevier Ltd. All rights reserved.

Vidyarthi V.S.,TU Dresden | Suchaneck G.,TU Dresden | Gerlach G.,TU Dresden | Levin A.A.,TechnischeUniversitat Dresden | And 2 more authors.
Thin Solid Films | Year: 2010

Radio frequency reactive magnetron sputtering from a composite target made of PbO pellets uniformly positioned on a metallic Ba disc has been utilized for BaPbO3 electrode deposition on 150 mm Si wafers. The reactive sputtering process has been analyzed in relation to sputtering parameters for composite targets with different percentage of PbO coverage. The process optimization method for in situ crystallized BaPbO3 thin film fabrication has been emphasized. The growth of BaPbO3 films has been discussed from the viewpoint of the BaO-PbO phase diagram and thermodynamics of Ban + 1PbnO3n + 1 (n = 1, 2, ∞) phase formation. The microstructure analysis of the deposited films has been performed with atomic force microscopy and wide-angle X-ray diffraction (XRD) techniques. The grazing angle XRD measurements reveal the formation of a Ba2PbO4 phase in the film fabricated at 450 °C. The Ba2PbO4 phase content decreases with decreasing substrate temperature. The BaPbO3 film deposited at a substrate temperature of 430 °C on naturally oxidized (001) Si wafers shows an electrical resistivity of 1.13 mΩ·cm. The BaPbO3 films deposited on SiO2 (native oxide)/Si wafer do not exhibit a preferred orientation whereas use of (111) Pt/SiO2/Si substrate results in highly (111)-oriented films. © 2009 Elsevier B.V. All rights reserved.

Wagner U.,TechnischeUniversitat Dresden | Ismail A.,TechnischeUniversitat Dresden | Kog F.,TechnischeUniversitat Dresden | Scherer R.J.,TechnischeUniversitat Dresden
eWork and eBusiness in Architecture, Engineering and Construction - Proceedings of the European Conference on Product and Process Modelling 2010 | Year: 2010

Using simulations for construction projects is still limited compared to other branches of industry like mass production in factories. The main reasons are the complexity of construction projects, the high expense and the long time needed to create a simulation model for each project and in addition to each objective asked for. A faster set up should possible if we could start from a formalised business process model. Business process models have been used widely to describe the logic, needed resources, and details of each single operation. This contribution presents preliminary research efforts about the transformation of business process models of construction projects to simulation models. The main focus is on the identification of mapping problem between typical business process patterns to simulation model patterns. This is studied on the hand of two simulations methods, namely discrete event simulation and Petri nets and three software implementations showing different object modelling data structures and frameworks as given constrains. © 2010 Taylor & Francis Group, London.

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