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University of Twente Publications (58.714 recursos)

University of Twente Repository provides publications of UT scientific staff, in many cases full text and publicly available.

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Mostrando recursos 1 - 20 de 12.386

  1. Data-based decision making put to the test

    Scheer, Emmeline Akky van der

  2. Compatibilization of Silica-filled Natural Rubber Compounds by Functionalized Low Molecular Weight Polymer

    Saramolee, P.; Sahakaro, K.; Lopattananon, N.; Dierkes, W.K.; Noordermeer, J.W.M.

  3. Structural network connectivity and cognition in cerebral small vessel disease

    Tuladhar, A.M.; Dijk, E.; Zwiers, M.P.; Norden, A.G.W. van; Laat, K.F. de; Shumskaya, E.; Norris, D.G.; Leeuw, F.E. de

  4. Simultaneous multislice (SMS) imaging techniques.

    Barth, M.; Breuer, F.; Koopmans, P.J.; Norris, D.G.; Poser, B.A.

  5. Ion acceleration in the transparent regime and the critical influence of the plasma density scale length

    Loch, R.A.; Ceccotti, T.; Quere, F.; George, H.; Bonnaud, G.; Réau, F.; D'Oliviera, P.; Luttikhof, M.J.H.; Bijkerk, F.; Boller, K-J.; Blaclard, G.; Combis, P.

  6. Selective Activation of the Deep Layers of the Human Primary Visual Cortex by Top-Down Feedback.

    Kok, P.; Bains, L.J.; Mourik, T.; Norris, D.G.; Lange, F.P.

  7. Factors Associated With 8-Year Mortality in Older Patients With Cerebral Small Vessel Disease: The Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort (RUN DMC) Study.

    Holst, H.M. van der; Uden, I.W.M. van; Tuladhar, A.M.; Laat, K.F. de; Norden, A.G.W. van; Norris, D.G.; Dijk, E.J. van; Rutten-Jacobs, L.C.A.; Leeuw, F.E. de

  8. The potential for microfluidics in electrochemical energy systems

    Modestino, Miquel A.; Fernandez Rivas, David; Hashemi, Seyyed Mohammad Hosseini; Gardeniers, Han; Psaltis, Demetri
    Flow based electrochemical energy conversion devices have the potential to become a prominent energy storage technology in a world driven by renewable energy sources. The optimal design of these devices depends strongly on the tradeoffs between the losses associated with multiple transport processes: convection and diffusion of reactants and products, migration of ionic species, and electrical charge transport. In this article we provide a balanced assesment of the compromise between these losses and demonstrate that for a broad range of electrochemical reactors, the use of microfluidics can enhance the energy conversion efficiency. Moreover, we propose proven scale-up strategies of microelectrochemical...

  9. Synergy of Microfluidics and Ultrasound: Process Intensification Challenges and Opportunities

    Fernandez Rivas, David; Kuhn, Simon
    A compact snapshot of the current convergence of novel developments relevant to chemical engineering is given. Process intensification concepts are analysed through the lens of microfluidics and sonochemistry. Economical drivers and their influence on scientific activities are mentioned, including innovation opportunities towards deployment into society. We focus on the control of cavitation as a means to improve the energy efficiency of sonochemical reactors, as well as in the solids handling with ultrasound; both are considered the most difficult hurdles for its adoption in a practical and industrial sense. Particular examples for microfluidic clogging prevention, numbering-up and scaling-up strategies are given....

  10. Conformational Compatibility Is Essential for Heterologous Aggregation of α-Synuclein

    Sidhu, Arshdeep; Segers-Nolten, Ine; Subramaniam, Vinod
    Under aggregation-prone conditions, soluble amyloidogenic protein monomers can self-assemble into fibrils or they can fibrillize on preformed fibrillar seeds (seeded aggregation). Seeded aggregations are known to propagate the morphology of the seeds in the event of cross-seeding. However, not all proteins are known to cross-seed aggregation. Cross-seeding has been proposed to be restricted either because of differences in the protein sequences or because of conformations between the seeds and the soluble monomers. Here, we examine cross-seeding efficiency between three α-synuclein sequences, wild-type, A30P, and A53T, each varying in only one or two amino acids but forming morphologically distinct fibrils. Results...

  11. Roadmap on Neurophotonics

    Cho, Yong Ku; Zheng, Guoan; Augustine, George J.; Hochbaum, Daniel; Cohen, Adam; Knopfel, Thomas; Pisanello, Ferruccio; Pavone, Francesco S.; Vellekoop, I.M.; Booth, Martin J.; Hu, Song; Zhu, Jiang; Chen, Zhongping; Hoshi, Yoko
    Mechanistic understanding of how the brain gives rise to complex behavioral and cognitive functions is one of science's grand challenges. The technical challenges that we face as we attempt to gain a systems-level understanding of the brain are manifold. The brain's structural complexity requires us to push the limit of imaging resolution and depth, while being able to cover large areas, resulting in enormous data acquisition and processing needs. Furthermore, it is necessary to detect functional activities and 'map' them onto the structural features. The functional activity occurs at multiple levels, using electrical and chemical signals. Certain electrical signals are...

  12. Experimental Measurement of the Static Coefficient of Friction at the Ti-Ti Taper Connection in Total Hip Arthroplasty

    Bitter, T.; Khan, I.; Marriott, T.; Schreurs, B.W.; Verdonschot, N.J.J.; Janssen, D.
    The modular taper junction in total hip replacements has been implicated as a possible source of wear. The finite-element (FE) method can be used to study the wear potential at the taper junction. For such simulations it is important to implement representative contact parameters, in order to achieve accurate results. One of the main parameters in FE simulations is the coefficient of friction. However, in current literature, there is quite a wide spread in coefficient of friction values (0.15 − 0.8), which has a significant effect on the outcome of the FE simulations. Therefore, to obtain more accurate results, one should use...

  13. Quantitative photoacoustic tomography by stochastic search, direct recovery of the optical absorption field

    Venugopal, M.; Es, P. van; Manohar, S.; Roy, D.; Vasu, R.M.
    We present, perhaps for the first time, a stochastic search algorithm in quantitative photoacoustic tomography (QPAT) for a one-step recovery of the optical absorption map from time-resolved photoacoustic signals. Such a direct recovery is free of the numerical inaccuracies inherent in conventional two-step approaches that depend on an accurate estimation of the absorbed energy distribution. The absorption profile parameterized as a vector stochastic process is additively updated over time recursions so as to drive the measurement-prediction misfit to a zero-mean white noise. The derivative-free additive update is a welcome departure from the conventional gradient-based methods requiring evaluation of Jacobians at...

  14. The state of the art in breast imaging using the Twente Photoacoustic Mammoscope: results from 31 measurements on malignancies

    Heijblom, M.; Piras, D.; Engh, F.M. van den; Schaaf, M. van der; Klaase, J.M.; Steenbergen, W.; Manohar, S.
    Objectives Photoacoustic mammography is potentially an ideal technique, however, the amount of patient data is limited. To further our understanding of the in vivo performance of the method and to guide further research and development, we imaged 33 breast malignancies using the research system – the Twente Photoacoustic Mammoscope (PAM). Methods Thirty-one patients participated in this retrospective, observational study. The study and informed consent procedure were approved by the local ethics committee. PAM uses 1,064 nm light for excitation with a planar, 588-element, 1-MHz ultrasound array for detection. Photoacoustic lesion visibility and appearance were compared with conventional imaging (x-ray mammography and ultrasonography) findings,...

  15. Lipid Head Group Charge and Fatty Acid Configuration Dictate Liposome Mobility in Neurofilament Networks

    Arends, F.; Chaudhary, H.; Janmey, P.; Claessens, M.M.A.E.; Lieleg, O.
    Intermediate filaments constitute a class of biopolymers whose function is still poorly understood. One example for such intermediate filaments is given by neurofilaments, large macromolecules that fill the axon of neurons. Here, reconstituted networks of purified porcine neurofilaments are studied and the diffusion behavior of different nanoparticles in the biopolymer network is evaluated. A strong dependence of particle diffusion on the charge state of the particles, and – for liposomes – also on the fatty acid configuration of lipids is observed. The results suggest that both electrostatic and hydrophobic interactions contribute to nanoparticle trapping in neurofilament networks, and that the...

  16. Size-selective analyte detection with a Young Interferometer sensor using multiple wavelenghts

    Mulder, H.K.P.; Blum, C.; Subramaniam, V.; Kanger, J.S.
    We present a method to discriminate between analytes based on their size using multiple wavelengths in a Young interferometer. We measured the response of two wavelengths when adding 85 nm beads (representing specific binding), protein A (representing non-specific binding) and D-glucose (inducing a bulk change) to our sensor. Next, the measurements are analysed using a approach based on theoretical analysis, and a ratio-based analysis approach to discriminate between bulk changes and the binding of the different sized substances. Moreover, we were able to discriminate binding of 85 nm beads from binding of protein A (~2 nm) in a blind experiment...

  17. Tandem pulsed acousto-optics: obtaining the tagged light fraction from modulated non-ideal speckle patterns

    Resink, S.G.; Steenbergen, W.
    Recently we presented novel methods for acousto-optic (AO) imaging of biological tissues, taking (1) the mean square difference of speckle patterns (subtraction method) or (2) the contrast of the summation of speckle patterns (summation method) acquired from nanosecond pulses of coherent light, fired at different ultrasound phases. In this study we relate the two methods both analytically and experimentally. We experimentally show that these two methods are nearly identical provided that the maximum achievable speckle contrast is determined correctly. We show with simulations that after correction the outcome is independent of experimental detection parameters. This makes the AO methods in...

  18. Vascularization and Angiogenesis in Tissue Engineering: Beyond Creating Static Networks

    Rouwkema, J.; Khademhosseini, A.
    Engineered tissues need a vascular network to supply cells with nutrients and oxygen after implantation. A network that can connect to the vasculature of the patient after implantation can be included during in vitro culture. For optimal integration, this network needs to be highly organized, including venules, capillaries, and arterioles, to supply all of the cells with sufficient nutrients. Owing to the importance of vascularization for the clinical applicability of tissue engineering, many approaches have been investigated to include an organized vascular network in tissue constructs. This review will give an overview of recent efforts, and will propose future perspectives...

  19. Synthetic imagery for the automated detection of rip currents

    Pitman, S.; Gallop, S.L.; Haigh, I.D.; Mahmoodi, S.; Masselink, G.; Ranasinghe, R.W.M.R.J.
    Rip currents are a major hazard on beaches worldwide. Although in-situ measurements of rips can be made in the field, it is generally safer and more cost effective to employ remote sensing methods, such as coastal video imaging systems. However, there is no universal, fully-automated method capable of detecting rips in imagery. In this paper we discuss the benefits of image manipulation, such as filtering, prior to rip detection attempts. Furthermore, we present a new approach to detect rip channels that utilizes synthetic imagery. The creation of a synthetic image involves the partitioning of the ‘parent’ image into key areas,...

  20. Potential of video cameras in assessing event and seasonal coastline behaviour: Grand Popo, Benin (Gulf of Guinea)

    Abessolo Ondoa, G.; Almar, R.; Kestenare, E.; Bahini, A.; Houngue, G-H.; Jouanno, J.; Du Penhoat, Y.; Castelle, B.; Melet, A.; Meyssignac, B.; Anthony, E.J.; Laibi, R.; Alory, G.; Ranasinghe, R.W.M.R.J.
    In this study, we explore the potential of a nearshore video system to obtain a long-term estimation of coastal variables (shoreline, beach slope, sea level elevation and wave forcing) at Grand Popo beach, Benin, West Africa, from March 2013 to February 2015. We first present a validation of the video system with field data over a 10-day experiment conducted on Grand Popo beach in 2014. Secondly, 2-years daily and monthly timeseries are extracted and their variability is described as a function of regional forcing and climatic modes. All variables show large monthly variability. The longshore sediment transport estimated locally from...

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