@article{54934, abstract = {{Aldosterone is thought to be the main hormone to stimulate the epithelial sodium channel (ENaC) in the aldosterone-sensitive distal nephron (ASDN) comprising the late distal convoluted tubule (DCT2), the connecting tubule (CNT) and the entire collecting duct (CD). There is immunohistochemical evidence for an axial gradient of ENaC expression along the ASDN with highest expression in the DCT2 and CNT. However, most of our knowledge about renal ENaC function stems from studies in the cortical collecting duct (CCD). Here we investigated ENaC function in the transition zone of DCT2/CNT or CNT/CCD microdissected from mice maintained on different sodium diets to vary plasma aldosterone levels. Single-channel recordings demonstrated amiloride-sensitive Na(+) channels in DCT2/CNT with biophysical properties typical for ENaC previously described in CNT/CCD. In animals maintained on a standard salt diet, the average ENaC-mediated whole cell current ($\Delta$I(ami)) was higher in DCT2/CNT than in CNT/CCD. A low salt diet increased $\Delta$I(ami) in CNT/CCD but had little effect on $\Delta$I(ami) in DCT2/CNT. To investigate whether aldosterone is necessary for ENaC activity in the DCT2/CNT, we used aldosterone synthase knockout (AS(-/-)) mice that lack aldosterone. In CNT/CCD of AS(-/-) mice, $\Delta$I(ami) was lower than that in wild-type (WT) animals and was not stimulated by a low salt diet. In contrast, in DCT2/CNT of AS(-/-) mice, $\Delta$I(ami) was similar to that in DCT2/CNT of WT animals both on a standard and on a low salt diet. We conclude that ENaC function in the DCT2/CNT is largely independent of aldosterone which is in contrast to its known aldosterone sensitivity in CNT/CCD.}}, author = {{Nesterov, Viatcheslav and Dahlmann, Anke and Krueger, Bettina and Bertog, Marko and Loffing, Johannes and Korbmacher, Christoph}}, journal = {{American Journal of Physiology-Renal Physiology}}, number = {{9}}, pages = {{F1289–F1299}}, publisher = {{American Physiological Society}}, title = {{{Aldosterone-dependent and -independent regulation of the epithelial sodium channel (ENaC) in mouse distal nephron}}}, doi = {{10.1152/ajprenal.00247.2012}}, volume = {{303}}, year = {{2012}}, } @article{54939, abstract = {{Background: Renal tubular epithelial cells of proximal and distal origin differ markedly in their physiological functions. Therefore, we hypothesized that they also differ in their capacity to undergo epithelial to mesenchymal alterations. Results: We used cultures of freshly isolated primary human tubular cells. To distinguish cells of different tubular origin we took advantage of the fact that human proximal epithelial cells uniquely express N-cadherin instead of E-cadherin as major cell-cell adhesion molecule. To provoke mesenchymal alteration we treated these cocultures with TGF-$\beta$ for up to 6 days. Within this time period, the morphology of distal tubular cells was barely altered. In contrast to tubular cell lines, E-cadherin was not down-regulated by TGF-$\beta$, even though TGF-$\beta$ signal transduction was initiated as demonstrated by nuclear localization of Smad2/3. Analysis of transcription factors and miRNAs possibly involved in E-cadherin regulation revealed high levels of miRNAs of the miR200-family, which may contribute to the stability of E-cadherin expression in human distal tubular epithelial cells. By contrast, proximal tubular epithelial cells altered their phenotype when treated with TGF-$\beta$. They became elongated and formed three-dimensional structures. Rho-kinases were identified as modulators of TGF-$\beta$-induced morphological alterations. Non-specific inhibition of Rho-kinases resulted in stabilization of the epithelial phenotype, while partial effects were observed upon downregulation of Rho-kinase isoforms ROCK1 and ROCK2. The distinct reactivity of proximal and distal cells was retained when the cells were cultured as polarized cells. Conclusions: Interference with Rho-kinase signaling provides a target to counteract TGF-$\beta$-mediated mesenchymal alterations of epithelial cells, particularly in proximal tubular epithelial cells. Furthermore, primary distal tubular cells differed from cell lines by their high phenotypic stability which included constant expression of E-cadherin. Our cell culture system of primary epithelial cells is thus suitable to understand and modulate cellular remodeling processes of distinct tubular cells relevant for human renal disease.}}, author = {{Keller, Christof and Kroening, Sven and Zuehlke, Jonathan and Kunath, Frank and Krueger, Bettina and Goppelt-Struebe, Margarete}}, issn = {{1932-6203}}, journal = {{PLOS ONE}}, number = {{8}}, pages = {{e43584}}, publisher = {{Public Library of Science}}, title = {{{Distinct Mesenchymal Alterations in N-Cadherin and E-Cadherin Positive Primary Renal Epithelial Cells}}}, doi = {{10.1371/journal.pone.0043584}}, volume = {{7}}, year = {{2012}}, } @inproceedings{36994, abstract = {{This paper proposes a quality driven, simulation based approach to functional design verification, which applies mainly to IP-level HDL designs with well specified test instruction format and is evaluated on a soft microprocessor core MB-LITE [5]. The approach utilizes mutation analysis as the quality metric to steer an automated simulation data generation process. It leads to a simulation flow with two phases towards an enhanced mutation analysis result. First in a random simulation phase, an in-loop heuristics is deployed and adjusts dynamically the test probability distribution so as to improve the coverage efficiency. Next, for each remaining hard-to-kill mutant, a search heuristics on test input space is developed to iteratively locate a target test, using a specific objective cost function for the goal of killing HDL mutant. The effectiveness of this integrated two-phase simulation flow is demonstrated by the results with the MB-LITE microprocessor IP.}}, author = {{Xie, Tao and Müller, Wolfgang and Letombe, Florian}}, booktitle = {{Proceedings of SOCC2012}}, keywords = {{Analytical models, Hardware design languages, Microprocessors, Cost function, Data models, Search problems, IP networks}}, publisher = {{IEEE}}, title = {{{Mutation-Analysis Driven Functional Verification of a Soft Microprocessor}}}, doi = {{10.1109/SOCC.2012.6398362}}, year = {{2012}}, } @article{24894, author = {{Mahnken, Rolf and Wolff, M. and Schneidt, A. and Böhm, M.}}, issn = {{0749-6419}}, journal = {{International Journal of Plasticity}}, pages = {{1--26}}, title = {{{Multi-phase transformations at large strains – Thermodynamic framework and simulation}}}, doi = {{10.1016/j.ijplas.2012.05.009}}, year = {{2012}}, } @article{39724, author = {{Redler, Andreas and Kitzerow, Heinz-Siegfried}}, issn = {{1042-7147}}, journal = {{Polymers for Advanced Technologies}}, keywords = {{Polymers and Plastics}}, number = {{1}}, pages = {{7--9}}, publisher = {{Wiley}}, title = {{{Three-dimensional structure in holographic polymer-dispersed liquid crystals}}}, doi = {{10.1002/pat.3040}}, volume = {{24}}, year = {{2012}}, } @article{40231, author = {{Meier-Gräwe, Uta and Wagenknecht, Inga}}, journal = {{Frühe Kindheit}}, pages = {{24--29}}, publisher = {{Deutsche Liga für das Kind in Familie und Gesellschaft e. V.}}, title = {{{Frühe Hilfen sind eine Zukunftsinvestition}}}, volume = {{14}}, year = {{2012}}, } @inproceedings{40820, abstract = {{An alternating optimization algorithm was recently proposed for the K-user multiple-input multiple-output (MIMO) interference channel. For flat-fading channels and feasible problems, this algorithm successfully aligns the interfering signals exploiting the spatial dimensions. In this paper, we consider the case in which all pairwise MIMO channels are frequency-selective (convolutive), and the users transmit broadband signals using a single-carrier scheme. Unlike the flat-fading case, for frequency-selective channels it is necessary to add a spectral mask in the frequency response of the precoders and decoders to avoid trivial solutions. We show in the paper that each step of the alternating minimization algorithm can be reformulated as a convex optimization problem in which the autocorrelation function of the precoders or decoders is obtained. Upon convergence, a final spectral factorization stage must be applied to obtain the precoders and decoders from their autocorrelation functions. Simulation results are provided to illustrate the performance of the proposed algorithm.}}, author = {{Lameiro, Christian and Vía, Javier and Santamaría, Ignacio and Heath Jr., Robert W.}}, booktitle = {{Proc.\ IEEE Int.\ Conf.\ Acoustics, Speech and Signal Process.}}, title = {{{Interference Leakage Minimization for Convolutive MIMO Interference Channels}}}, doi = {{10.1109/ICASSP.2012.6288506}}, year = {{2012}}, } @article{40173, abstract = {{Here, There, Everywhere Random walks are a powerful mathematical method that can be used to simulate certain processes in biology, chemistry, or even the stock market. They present a statistical method for mapping the possible routes that processes can take. Quantum walks are expected to be able to probe multiple paths simultaneously. Quantum walks have been demonstrated for one-dimensional, or straight-line, walks. Now, Schreiber et al. (p. 55 , published online 8 March) demonstrate an optical system that can simulate quantum walks over a two-dimensional system, thereby providing the capability of describing much more complex processes. }}, author = {{Schreiber, Andreas and Gábris, Aurél and Rohde, Peter P. and Laiho, Kaisa and Štefaňák, Martin and Potoček, Václav and Hamilton, Craig and Jex, Igor and Silberhorn, Christine}}, issn = {{0036-8075}}, journal = {{Science}}, keywords = {{Multidisciplinary}}, number = {{6077}}, pages = {{55--58}}, publisher = {{American Association for the Advancement of Science (AAAS)}}, title = {{{A 2D Quantum Walk Simulation of Two-Particle Dynamics}}}, doi = {{10.1126/science.1218448}}, volume = {{336}}, year = {{2012}}, } @article{17215, author = {{Schilling, Malte and Rohlfing, Katharina and Cruse, Holk}}, issn = {{1664-1078}}, journal = {{Frontiers in Psychology}}, number = {{405}}, pages = {{405}}, publisher = {{Frontiers Media SA}}, title = {{{Prediction as internal simulation: Taking chances in what to do next}}}, doi = {{10.3389/fpsyg.2012.00405}}, volume = {{3}}, year = {{2012}}, } @inproceedings{40809, abstract = {{Interference alignment (IA) has been shown to achieve the maximum degrees of freedom in the multiple-input multiple-output (MIMO) K-user interference channel (IFC). In the presence of frequency-selective channels, orthogonal frequency-division multiplexing (OFDM) is typically used to deal with the multipath nature of the channel. While IA techniques can be applied in a per-subcarrier basis (post-FFT), the existence of symbol timing offsets (STOs) between the desired and the interfering OFDM symbols decreases the system performance dramatically. To solve this problem, we design pre-FFT precoders and decoders for single-beam MIMO IFCs for OFDM transmissions. Since the IA decoders operate before the FFT, they mitigate the interference before synchronization takes place. We show that our proposed scheme improves the system performance when STOs occur, in comparison with traditional post-FFT IA techniques. We provide simulation results to compare post- and pre-FFT beamforming techniques and to illustrate the performance of the proposed method.}}, author = {{Lameiro, Christian and Vía, Javier and Santamaría, Ignacio and Heath Jr., Robert W.}}, booktitle = {{Proc. Int. Symp. Wireless Comm. Syst.}}, title = {{{Pre- and Post-FFT Interference Leakage Minimization for MIMO OFDM Networks}}}, doi = {{10.1109/ISWCS.2012.6328429}}, year = {{2012}}, } @article{39520, author = {{Brockmeier, A and Rodriguez, F J Santos and Harrison, M and Hilleringmann, Ulrich}}, issn = {{0960-1317}}, journal = {{Journal of Micromechanics and Microengineering}}, keywords = {{Electrical and Electronic Engineering, Mechanical Engineering, Mechanics of Materials, Electronic, Optical and Magnetic Materials}}, number = {{12}}, publisher = {{IOP Publishing}}, title = {{{Surface tension and its role for vertical wet etching of silicon}}}, doi = {{10.1088/0960-1317/22/12/125012}}, volume = {{22}}, year = {{2012}}, } @article{39522, author = {{Brockmeier, A and Rodriguez, F J Santos and Harrison, M and Hilleringmann, Ulrich}}, issn = {{0960-1317}}, journal = {{Journal of Micromechanics and Microengineering}}, keywords = {{Electrical and Electronic Engineering, Mechanical Engineering, Mechanics of Materials, Electronic, Optical and Magnetic Materials}}, number = {{12}}, publisher = {{IOP Publishing}}, title = {{{Surface tension and its role for vertical wet etching of silicon}}}, doi = {{10.1088/0960-1317/22/12/125012}}, volume = {{22}}, year = {{2012}}, } @article{15984, abstract = {{A new and promising approach to the reduction of greenhouse gas emissions is the use of improved lightweight constructions based on multi-material systems comprising sheet metal with local carbon fibre reinforced plastic (CFRP) reinforcements. The CFRP is used to reinforce highly stressed areas and can be aligned to specific load cases. The locally restricted application of CFRP means that the material costs can be effectively reduced by comparison to parts made entirely of CFRP on account of the expensive production process requiring the use of an autoclave. These parts are thus only used in high-priced products. The production of hybrid CFRP steel structures in a mass production process calls for an efficient production technology. Current research work within the scope of a collaborative research project running at the University of Paderborn is concentrating on the development of manufacturing processes for the efficient production of automotive structural components made up of sheet metal blanks with local CFRP patches. The project is focusing especially on basic research into the production of industrial components. The aim of the investigation is to create an efficient and controlled process for producing CFRP reinforced steel structures from semi-finished hybrid steel-CFRP material. This includes tool concepts and an appropriate process design to permit short process times. The basis of an efficient process design is an in-depth knowledge of the material behaviour, and hence a thorough characterisation was performed. Material parameters were determined for both simulation and forming. For this, monotonic tensile, shear and bending tests were conducted using both uncured prepregs and cured CFRP specimens. To achieve an accurate simulation of the forming process, a special material model for carbon fibre prepregs has been developed which also includes the anisotropic material behaviour resulting from fibre orientation, the viscoelastic behaviour caused by the matrix and the hardening effects that prevail during curing. Recent results show good qualitative agreement and will be presented in this paper. In order to control the properties of the hybrid components, four different tool concepts for the prepreg press technology have been developed and tested. The concepts are presented and the results of experimental investigations are discussed in this paper.}}, author = {{Schmidt, Hans Christian and Damerow, Ulf and Lauter, Christian and Gorny, Bernhard and Hankeln, Frederik and Homberg, Werner and Tröster, Thomas and Maier, Hans Jürgen and Mahnken, Rolf}}, issn = {{1662-9795}}, journal = {{Key Engineering Materials}}, pages = {{295--300}}, title = {{{Manufacturing Processes for Combined Forming of Multi-Material Structures Consisting of Sheet Metal and Local CFRP Reinforcements}}}, doi = {{10.4028/www.scientific.net/kem.504-506.295}}, year = {{2012}}, } @inproceedings{15986, author = {{Gorny, B. and Hankeln, Frederik and Lauter, Christian and Schmidt, H. C. and Damerow, U. and Mahnken, Rolf and Maier, H. J. and Tröster, Thomas and Homberg, Werner}}, location = {{Turin, Italy}}, title = {{{Simulation and manufacturing of deep drawn parts reinforced by carbon fibre prepregs}}}, year = {{2012}}, } @inproceedings{567, abstract = {{Heterogeneous machines are gaining momentum in the High Performance Computing field, due to the theoretical speedups and power consumption. In practice, while some applications meet the performance expectations, heterogeneous architectures still require a tremendous effort from the application developers. This work presents a code generation method to port codes into heterogeneous platforms, based on transformations of the control flow into function calls. The results show that the cost of the function-call mechanism is affordable for the tested HPC kernels. The complete toolchain, based on the LLVM compiler infrastructure, is fully automated once the sequential specification is provided.}}, author = {{Barrio, Pablo and Carreras, Carlos and Sierra, Roberto and Kenter, Tobias and Plessl, Christian}}, booktitle = {{Proceedings of the International Conference on High Performance Computing and Simulation (HPCS)}}, pages = {{559--565}}, publisher = {{IEEE}}, title = {{{Turning control flow graphs into function calls: Code generation for heterogeneous architectures}}}, doi = {{10.1109/HPCSim.2012.6266973}}, year = {{2012}}, } @article{52225, author = {{Schäfer, Mirko and Wagner, Johannes and Schlüter, Alexander and Hesselbach, Jens}}, issn = {{2305-9974}}, journal = {{SNE Simulation Notes Europe}}, number = {{1}}, pages = {{1--6}}, publisher = {{ARGESIM Arbeitsgemeinschaft Simulation News}}, title = {{{Energy Flows in Industrial Buildings and Machines using the Example of a Node Model}}}, doi = {{10.11128/sne.22.tn.10103}}, volume = {{22}}, year = {{2012}}, } @inbook{52419, author = {{Schlüter, Alexander and Schäfer, Mirko}}, booktitle = {{Energie- und klimaeffiziente Produktion: Grundlagen, Leitlinien und Praxisbeispiele}}, editor = {{Hesselbach, Jens}}, isbn = {{978-3-8348-0448-8}}, pages = {{101--102}}, publisher = {{Springer Vieweg}}, title = {{{Von der Modellbildung zur Simulation: Die Vorgehensweise}}}, year = {{2012}}, } @inproceedings{60458, abstract = {{Digital 3D models are key components in many industrial and scientific sectors. In numerous domains polygonmeshes have become a de facto standard for model representation. In practice meshes often have a number ofdefects and flaws that make them incompatible with quality requirements of specific applications. Hence, repairingsuch defects in order to achieve compatibility is a highly important task - in academic as well as industrial applications. In this tutorial we first systematically analyze typical application contexts together with their requirementsand issues, as well as the various types of defects that typically play a role. Subsequently, we considerexisting techniques to process, repair, and improve the structure, geometry, and topology of imperfect meshes,aiming at making them appropriate to case-by-case requirements. We present seminal works and key algorithms,discuss extensions and improvements, and analyze the respective advantages and disadvantages depending onthe application context. Furthermore, we outline directions where further research is particularly important orpromising.}}, author = {{Campen, Marcel and Attene, Marco and Kobbelt, Leif}}, booktitle = {{Eurographics 2012 Tutorials}}, title = {{{A Practical Guide to Polygon Mesh Repairing}}}, doi = {{10.2312/CONF/EG2012/TUTORIALS/T4}}, year = {{2012}}, } @article{62788, abstract = {{AbstractWe present a novel approach for the simulation of solid to solid phase‐transformations in polycrystalline materials. To facilitate the utilization of a non‐affine micro‐sphere formulation with volumetric‐deviatoric split, we introduce Helmholtz free energy functions depending on volumetric and deviatoric strain measures for the underlying scalar‐valued phase‐transformation model. As an extension of affine micro‐sphere models [5], the non‐affine micro‐sphere formulation with volumetric‐deviatoric split allows to capture different Young's moduli and Poisson's ratios on the macro‐scale [1]. As a consequence, the temperature‐dependent free energy assigned to each individual phase takes the form of an elliptic paraboloid in volumetric‐deviatoric strain space, where the energy landscape of the overall material is obtained from the contributions of the individual constituents. For the evolution of volume fractions, we use an approach based on statistical physics–taking into account actual Gibbs energy barriers and transformation probabilities [2]. The computation of individual energy barriers between the phases considered is enabled by numerical minimization of parametric intersection curves of elliptic Gibbs energy paraboloids. (© 2012 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)}}, author = {{Ostwald, Richard and Bartel, Thorsten and Menzel, Andreas}}, issn = {{1617-7061}}, journal = {{PAMM}}, number = {{1}}, pages = {{277--278}}, publisher = {{Wiley}}, title = {{{Simulation of phase‐transformations based on numerical minimization of intersecting Gibbs energy potentials}}}, doi = {{10.1002/pamm.201210129}}, volume = {{12}}, year = {{2012}}, } @article{4136, abstract = {{Results of atomistic simulations aimed at understanding precipitation of the highly attractive wide band gap semiconductor material silicon carbide in silicon are presented. The study involves a systematic investigation of intrinsic and carbon-related defects as well as defect combinations and defect migration by both, quantummechanical first-principles as well as empirical potential methods. Comparing formation and activation energies, ground-state structures of defects and defect combinations as well as energetically favorable agglomeration of defects are predicted. Moreover, accurate ab initio calculations unveil limitations of the analytical method based on a Tersoff-like bond order potential. A work-around is proposed in order to subsequently apply the highly efficient technique on large structures not accessible by first-principles methods. The outcome of both types of simulation provides a basic microscopic understanding of defect formation and structural evolution particularly at non-equilibrium conditions strongly deviated from the ground state as commonly found in SiC growth processes. A possible precipitation mechanism, which conforms well to experimental findings and clarifies contradictory views present in the literature is outlined.}}, author = {{Zirkelbach, F. and Stritzker, B. and Nordlund, K. and Schmidt, Wolf Gero and Rauls, E. and Lindner, Jörg K. N.}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, number = {{10-11}}, pages = {{1968--1973}}, publisher = {{Wiley}}, title = {{{First-principles and empirical potential simulation study of intrinsic and carbon-related defects in silicon}}}, doi = {{10.1002/pssc.201200198}}, volume = {{9}}, year = {{2012}}, }