47 research outputs found
Laser-Grafted Molecularly Imprinted Polymers for the Detection of Histamine from Organocatalyzed Atom Transfer Radical Polymerization
No full text© 2019 American Chemical Society. To be applicable to in vivo measuring, molecularly imprinted polymer (MIP) based sensors need to have high reproducibility, require miniaturization, and must be free of toxic materials (such as heavy metals). To address these requirements, a metal-free photo atom transfer radical polymerization (ATRP) grafting procedure is described using a pulsed UV laser as light source to create thin molecularly imprinted polymer (MIP) films (∼10 nm thickness) on a sensor surface. Analysis via X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed the composition of the polymer film and the necessity for an excess of functional monomer to ensure its incorporation are demonstrated. MIP films were templated toward the target molecule histamine, for which in vivo studies can reveal unknown pathological pathways of inflammatory bowel diseases. By use of impedance spectroscopy, the biosensor surface is characterized in comparison to nonimprinted film grafts, and a high selectivity and sensitivity toward the target molecule are identified, revealing a histamine concentration limit of detection of 3.4 nM.sponsorship: The authors are grateful for funding by the Research Foundation Flanders (FWO) via the project G.0B25.14N, and support from the Karlsruhe Micro Nano Facility (KMNF) is also kindly acknowledged. The authors wish to thank Mrs. Emely Bopp (IFG,KIT) for performing some TOF-SIMS experiments. Furthermore, the authors thank Prof. M. Wubbenhorst and Drs. P. Cornelis (both in KU Leuven) for making the impedance analyzer device available and for assistance in the evaluation of impedance spectroscopy data. (Research Foundation Flanders (FWO)|G.0B25.14N, Karlsruhe Micro Nano Facility (KMNF))status: Publishe
From colossal magnetoresistance to solar cells: An overview on 66 years of research into perovskites
No full text© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Perovskites are a huge family of compounds to which the natural titanium mineral CaTiO3 is the common ancestor. The cubic structure looks apparently simple, but the variety of metal ions and mixtures thereof that fit into a perovskite lattice is tremendous. Even in the case that the ionic radii do not allow for a perfect cubic ordering, there are various superstructures and orbital-ordering effects to cope elegantly with distortions. The compositional and structural flexibility offers a large toolbox to design and synthesize perovskites with tailored properties searched for by physicists, chemists, materials scientists and device engineers. These materials are equally of interest for fundamental studies and for applied research while both viewpoints cross-fertilize each other regularly. Our overview starts with the discovery of ferromagnetism in manganites in 1950 and ranges until 2016: Today, halide perovskites are fully in focus for their potential in photovoltaic applications. This is certainly not an endpoint, but another milestone in a long series of often-unexpected discoveries on an ‘evergreen material’. Ball-and-stick model of the ideal cubic perovskite structure. The cation at the central position or ‘B site’ (small black dot) defines the group name (e.g., titanates) and plays a key role for the physical properties of the material.sponsorship: The Ph.D. project of co-author Gideon Wackers is funded by FWO - Research Foundation Flanders, project no. G.0B25.14N. J. Vanacken would like to acknowledge the support from Methusalem Funding by the Flemish Government. Furthermore, the authors are grateful to Prof. Dr. Gerhard Jakob (Johannes-Gutenberg-University Mainz, Germany) for advice on the crystallographic aspects of perovskites, to Prof. Dr. Christ Glorieux (KU Leuven) for advice on pyroelectric temperature detectors, and to Prof. Dr. Margriet J. Van Bael (KU Leuven) for her input on multiferroic materials. (FWO - Research Foundation Flanders|G.0B25.14N, Flemish Government)status: Publishe
Array formatting of the heat-transfer method (HTM) for the detection of small organic molecules by molecularly imprinted polymers
No full textArray formatting of the heat-transfer method (HTM) for the detection of small organic molecules by molecularly imprinted polymers
No full textSurface capturing and multigrid for steady free-surface water flows
No full textSurface capturing is a technique for modelling the water surface in numerical computations of water flow: the computational grid is not deformed, a separate surface model gives the location of the water surface in the grid. Surface capturing is generally applicable and can handle complicated ship geometries. For steady flow problems, the major disadvantage is that most capturing methods do not allow the use of fast solution methods. This thesis shows that fast solution of a surface capturing model is possible. For this, a flow model is derived that consists of conservation laws only. As these equations allow coupled solution, they can be solved efficiently for steady flows. The flow equations are discretised with a finite-volume method. The convective part is discretised with linearised Riemann fluxes, which guarantee the stability of the discretisation and good performance of the relaxation methods. A RANS turbulence model is added to the system. A multigrid solver is combined with line Gauss-Seidel smoothing. The source term in the turbulence model can make the line smoothing unstable. Therefore, a local adaptive damping is added to the smoother. Also, the mixture surface model and the turbulence model cause large differences in the solutions on fine and coarse grids, so nonlinear multigrid is ineffective. Our multigrid method combines nonlinear smoothing on the finest grid with linear coarse grid corrections. The discretisation is made second-order accurate with a limited scheme. To keep the water surface sharp, a compressive limiter is used for the volume fraction, that indicates the surface. The second-order accurate equations are solved with defect correction. Results are presented for a 2D channel flow with a bottom bump. The capturing model gives good agreement with experiments and existing numerical models. The multigrid solution is up to 20 times faster than single-grid line smoothing. The thesis also contains two smaller topics: an unstructured grid refinement method for ship flow grids and a study of shock behaviour for a compressible two-fluid flow model.Aerospace Engineerin
Accurate and efficient computation of steady water flow with surface waves and turbulence
No full textA surface capturing method is developed for steady water-air flow with gravity. Second-order accuracy is obtained with flux limiting and turbulence is modeled with Menter's model. The model is solved efficiently with a combination of multigrid and defect correction. Results for two test cases confirm the efficiency and accuracy of the method.Aerospace Engineerin
Argumentative resistance to violence metaphors for cancer:An analytical study of argumentation against metaphor
No full textViolence metaphors for cancer – such as ‘she is fighting cancer’ or ‘she lost her battle against cancer’ – are highly common in discourse about cancer. At the same time, these metaphors are controversial and contested. The present dissertation sheds novel light on the metaphors’ contentious status by conducting a close analysis of standpoints and arguments that are put forward against these metaphors in public discourse. The analysis is guided by the pragma-dialectical approach to argument analysis and approaches to metaphor analysis that are grounded in cognitive linguistics. In this dissertation, the author first examines how different types of argumentation in resistance to violence metaphors for cancer can relate to specific features of the contested metaphors. Subsequently, she examines the nature of different resistance standpoints and the dimensions of metaphor use these standpoints may be targeted at. The second part of the dissertation is focused on the analysis of arguments that are put forward against implications of violence metaphors for cancer, as well as the ways in which these implications can be countered by means of metaphor extension. Together, the dissertation’s findings demonstrate the multifacetedness of argumentative resistance against violence metaphors, and how such resistance can take different forms depending on a protagonist’s precise point of view and their arguments for objecting to a particular (property of) metaphor. Lastly, the dissertation demonstrates the value of combining theoretical and empirical knowledge on argumentation and metaphor in order to gain a better understanding of the ways in which metaphors are received and critically reflected upon
Argumentative resistance to violence metaphors for cancer:An analytical study of argumentation against metaphor
No full textViolence metaphors for cancer – such as ‘she is fighting cancer’ or ‘she lost her battle against cancer’ – are highly common in discourse about cancer. At the same time, these metaphors are controversial and contested. The present dissertation sheds novel light on the metaphors’ contentious status by conducting a close analysis of standpoints and arguments that are put forward against these metaphors in public discourse. The analysis is guided by the pragma-dialectical approach to argument analysis and approaches to metaphor analysis that are grounded in cognitive linguistics. In this dissertation, the author first examines how different types of argumentation in resistance to violence metaphors for cancer can relate to specific features of the contested metaphors. Subsequently, she examines the nature of different resistance standpoints and the dimensions of metaphor use these standpoints may be targeted at. The second part of the dissertation is focused on the analysis of arguments that are put forward against implications of violence metaphors for cancer, as well as the ways in which these implications can be countered by means of metaphor extension. Together, the dissertation’s findings demonstrate the multifacetedness of argumentative resistance against violence metaphors, and how such resistance can take different forms depending on a protagonist’s precise point of view and their arguments for objecting to a particular (property of) metaphor. Lastly, the dissertation demonstrates the value of combining theoretical and empirical knowledge on argumentation and metaphor in order to gain a better understanding of the ways in which metaphors are received and critically reflected upon
Academische theologie in Middelnederlandse verzen
No full textIn this article the third text in ms. Tübingen, Universitätsbibliothek, Me.IV.3 is analysed. It concerns a text on the last judgment in verse. It is the only Middle Dutch text in verse on this subject and it is also unique because it announces in the prologue that the content will be based on the work of Thomas Aquinas and Peter Lombard. For the first half of the text this is true. Often a part of the text is based on a passage in the Summa theologiae or the Sentences. This article lists the subjects where this happens, shows how the passages from these academic handbooks were adapted and argues that the changes were made because the author wanted to give his public more insight in some miraculous aspects of the last judgment but combined with exhortations to live in such a way that they will be among the righteous when the judgment comes. To strengthen this last aim the last part of the text pays much attention to the severity of the judgment and the pains of hell that await the sinners. This part is based on non-academic sources, as are important parts of the first half (although this is not mentioned in the text itself). The end of this article reflects on this mix of sources and stresses that the existence of this text shows that we must be careful with generalisations about the public of religious texts in the vernacular
