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University of Twente Publications (60.939 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 27.563

  1. Gold Nanocomposite Bioink for Printing 3D Cardiac Constructs

    Zhu, K.; Shin, S.R.; Kempen, T. van; Li, Y.-C.; Ponraj, V.; Nasajpour, A.; Mandla, S.; Hu, N.; Liu, X.; Leijten, J.C.H.; Lin, Y.-D.; Hussain, M.A.; Zhang, Y.S.; Tamayol, A.; Khademhosseini, A.
    Bioprinting is the most convenient microfabrication method to create biomimetic three-dimensional (3D) cardiac tissue constructs, that can be used to regenerate damaged tissue and provide platforms for drug screening. However, existing bioinks, which are usually composed of polymeric biomaterials, are poorly conductive and delay efficient electrical coupling between adjacent cardiac cells. To solve this problem, a gold nanorod (GNR)-incorporated gelatin methacryloyl (GelMA)- based bioink is developed for printing 3D functional cardiac tissue constructs. The GNR concentration is adjusted to create a proper microenvironment for the spreading and organization of cardiac cells. At optimized concentrations of GNR, the nanocomposite bioink has a low viscosity, similar to pristine inks, which allows for...

  2. Exploiting the P L2,3 absorption edge for optics: spectroscopic and structural characterization of cubic boron phosphide thin films

    Huber, S.P.; Medvedev, V.V.; Meyer-Ilse, J.; Gullikson, E.; Padavala, B.; Edgar, J.H.; Sturm, J.M.; Kruijs, R.W.E. van de; Prendergast, D.; Bijkerk, F.
    The transmission of cubic boron phosphide (c-BP) thin films, prepared by chemical vapor deposition (CVD), was evaluated near the phosphorous L2,3 and boron K absorption edge. The c-BP films were analyzed with transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES), to study their structural and chemical properties. The TEM analysis reveals that c-BP initially grows in islands. The merging of the P L2,3, P K and B K absorption edges culminates in a sharp absorption feature starting at 130 eV, showing that c-BP can be used in applications that require a relatively transparent material...

  3. Potential of Wake-Up Radio-Based MAC Protocols for Implantable Body Sensor Networks (IBSN)—A Survey

    Karuppiah Ramachandran, Vignesh Raja; Ayele, Eyuel D.; Meratnia, Nirvana; Havinga, Paul J.M.
    With the advent of nano-technology, medical sensors and devices are becoming highly miniaturized. Consequently, the number of sensors and medical devices being implanted to accurately monitor and diagnose a disease is increasing. By measuring the symptoms and controlling a medical device as close as possible to the source, these implantable devices are able to save lives. A wireless link between medical sensors and implantable medical devices is essential in the case of closed-loop medical devices, in which symptoms of the diseases are monitored by sensors that are not placed in close proximity of the therapeutic device. Medium Access Control (MAC)...

  4. Cocoon: A lightweight opportunistic networking middleware for community-oriented smart mobile applications

    Türkes, Okan; Scholten, Hans; Havinga, Paul J.M.
    Modern society is surrounded by an ample spectrum of smart mobile devices. This ubiquity forms a high potential for community-oriented opportunistic ad hoc networking applications. Nevertheless, today’s smart mobile devices such as smartphones, tablets, and wristbands are still onerous to automatically establish mobile ad hoc connections with our physical circle of friends and between occasional contact opportunities. Motivated by this, this study presents Cocoon as a lightweight middleware proposed for smart mobile platforms to support mobile opportunistic communications for general public use. Cocoon employs an adaptive context-aware service that can fairly coordinate a multitude of concurrently-running networking applications. Along with...

  5. Determinants of the nurses’ and nursing assistants’ request for antipsychotics for people with dementia

    Janus, Sarah I.M.; Manen, Jeannette G. van; IJzerman, Maarten J.; Bisseling, Marloes
    Although physicians are responsible for writing the antipsychotic prescriptions for patients with dementia, the initiative is often taken by nurses or nursing assistants. To reduce antipsychotics uses, one needs to understand the reasons for nurses and nursing assistants to request them. This study gives an overview of the influencing factors for this request based on the Theory of Planned Behavior in which attitude, beliefs, and behavioral control is thought to influence the intention to request, which in turn affects the behavior to request for a prescription. Eighty-one nurses and nursing assistants of one Dutch nursing home organization completed an online survey. Nurses...

  6. A systematic review and checklist presenting the main challenges for health economic modeling in personalized medicine: towards implementing patient-level models

    Degeling, K.; Koffijberg, Hendrik; IJzerman, Maarten J.
    Introduction: The ongoing development of genomic medicine and the use of molecular and imaging markers in personalized medicine (PM) has arguably challenged the field of health economic modeling (HEM). This study aims to provide detailed insights into the current status of HEM in PM, in order to identify if and how modeling methods are used to address the challenges described in literature. Areas covered: A review was performed on studies that simulate health economic outcomes for personalized clinical pathways. Decision tree modeling and Markov modeling were the most observed methods. Not all identified challenges were frequently found, challenges regarding companion diagnostics,...

  7. A closed testing procedure to select an appropriate method for updating prediction models

    Vergouwe, Yvonne; Nieboer, Daan; Oostenbrink, Rianne; Debray, Thomas P.A.; Murray, Gordon D.; Kattan, Michael W.; Koffijberg, Hendrik; Moons, Karel G.M.; Steyerberg, Ewout W.
    Prediction models fitted with logistic regression often show poor performance when applied in populations other than the development population. Model updating may improve predictions. Previously suggested methods vary in their extensiveness of updating the model. We aim to define a strategy in selecting an appropriate update method that considers the balance between the amount of evidence for updating in the new patient sample and the danger of overfitting. We consider recalibration in the large (re-estimation of model intercept); recalibration (re-estimation of intercept and slope) and model revision (re-estimation of all coefficients) as update methods. We propose a closed testing procedure...

  8. Are Component Endpoints Equal? A Study into the Practice of Composite End Points in Clinical Trials

    Vaanholt, M.C.W.; Birgelen, C. von; Kok, M.M.; Weernink, M.G.M.; Til, J.A. van

  9. Weighing Clinical Evidence Using Patient Preferences: An Application of Probabilistic Multi-Criteria Decision Analysis

    Broekhuizen, Henk; IJzerman, Maarten J.; Hauber, A. Brett; Groothuis-Oudshoorn, Catharina G.M.
    The need for patient engagement has been recognized by regulatory agencies, but there is no consensus about how to operationalize this. One approach is the formal elicitation and use of patient preferences for weighing clinical outcomes. The aim of this study was to demonstrate how patient preferences can be used to weigh clinical outcomes when both preferences and clinical outcomes are uncertain by applying a probabilistic value-based multi-criteria decision analysis (MCDA) method. Probability distributions were used to model random variation and parameter uncertainty in preferences, and parameter uncertainty in clinical outcomes. The posterior value distributions and rank probabilities for each...

  10. Frequency width of open channels in multiple scattering media

    Bosch, J.; Goorden, S.A.; Mosk, A.P.
    We report optical measurements of the spectral width of open transmission channels in a three-dimensional diffusive medium. The light transmission through a sample is enhanced by efficiently coupling to open transmission channels using repeated digital optical phase conjugation. The spectral properties are investigated by enhancing the transmission, fixing the incident wavefront and scanning the wavelength of the laser. We measure the transmitted field to extract the field correlation function and the enhancement of the total transmission. We find that optimizing the total transmission leads to a significant increase in the frequency width of the field correlation function. Additionally we find...

  11. Optical transmission matrix as a probe of the photonic strength

    Akbulut, D.; Strudley, T.; Bertolotti, J.; Bakkers, E.P.A.M.; Muskens, O.L.; Pinkse, P.W.H.; Lagendijk, A.; Vos, W.L.
    We demonstrate that optical transmission matrices (TMs) provide a powerful tool to extract the photonic strength of disordered complex media, independent of surface effects. We measure the TM of a strongly scattering GaP nanowire medium and compare the singular value density of the measured TM to a random-matrix-based wave transport model. By varying the transport mean free path and effective refractive index in the model, we retrieve the photonic strength. From separate numerical simulations we conclude that the photonic strength derived from TM statistics is insensitive to the surface reflection at rear surface of the sample.

  12. 10 year survival after breast-conserving surgery plus radiotherapy compared with mastectomy in early breast cancer in the Netherlands: a population-based study

    Maaren, Marissa C. van; Munck, Linda de; Bock, G.H. (Truuske); Jobsen, Jan J.; Dalen, Thijs van; Linn, Sabine C.; Poortmans, Philip; Strobbe, Luc J.; Siesling, Sabine

  13. Borstsparende therapie en mastectomie vergeleken: overleving na borstkanker in een vroeg stadium

    Maaren, Marissa C. van; Munck, Linda de; Bock, G.H. (Truuske); Jobsen, Jan J.; Dalen, Thijs van; Linn, Sabine C.; Poortmans, Philip; Strobbe, Luc J.; Siesling, Sabine

  14. Breast-conserving therapy versus mastectomy: editorial

    Maaren, Marissa C. van; Poortmans, Philip; Siesling, Sabine

  15. Interrogating Metastatic Prostate Cancer Treatment Switch Decisions: A Multi-institutional Survey

    Lorente, David; Ravi, Praful; Mehra, Niven; Pezaro, Carmel; Omlin, Aurelius; Gilman, Alexa; Miranda, Miguel; Rescigno, Pasquale; Kolinsky, Michael; Porta, Nuria; Bianchini, Diletta; Tunariu, Nina; Perez, Raquel; Mateo, Joaquin; Payne, Heather; Terstappen, Leon; IJzerman, Maarten; Hall, Emma; Bono, Johann de

  16. Desalination by Electrodialysis Using a Stack of Patterned Ion-Selective Hydrogels on a Microfluidic Device

    Gumuscu, Burcu; Haase, A. Sander; Benneker, Anne M.; Hempenius, Mark A.; Berg, Albert van den; Lammertink, Rob G.H.; Eijkel, Jan C.T.
    This study reports a novel approach for separation of charged species using anion-exchange hydrogel (AEH) and cation-exchange hydrogel (CEH) in a microfluidic device. The capillary line pinning technique, which is applied in this study, enables in situ fabrication of alternating AEH and CEH that are placed in confined compartments. Adjacent enriched and depleted streams are obtained in continuous flow when a potential difference is applied over the hydrogel stack. The desalination performance of the microchip is demonstrated at different salt concentrations (0.01 × 10−3–1× 10−3m sodium chloride), potentials (10–100 V), current densities (12–28 A m−2), and liquid flow rates (0–5...

  17. Non-Rayleigh distribution of reflected intensity from photonic crystals with disorder

    Ojambati, Oluwafemi Stephen; Yeganegi, Elahe; Mosk, A.P.; Lagendijk, A.; Vos, W.L.

  18. Why observational studies are important in comparative effectiveness research: the effect of breast-conserving therapy and mastectomy in the real world

    Maaren, Marissa C. van; Poortmans, Philip; Strobbe, Luc J.; Munck, Linda de; Siesling, Sabine
    We thank Dr. Franceschini and colleagues for their comment (1) on our recently published article in the Lancet Oncology (2). First, it is completely justified to ask oneself whether results from observational studies are likely to arise from selection bias. It is extensively described that observational studies investigating treatment effects are prone to confounding by severity (3). However, in contrast to randomised controlled trials (RCTs), observational studies do reflect the real-world population. As long as we interpret the results carefully, as it should be done for RCTs as well, these types of studies are of additional value through their ability...

  19. Deciding to help: effects of risk and crisis communication

    Bakker, Marije H.; Kerstholt, José H.; Giebels, Ellen
    This study aimed to gain insight into the (combined) effects of risk and crisis communication on adequate behaviour during a crisis situation. In addition, it adds to the existing literature by examining the effects of risk and crisis communication on psychological factors that are involved in decision-making during a crisis. This study, utilizing a virtual environment, was a 3 (risk communication: risk information vs. risk information with course of action vs. control) × 2 (crisis communication: with recommended behaviours vs. without recommended behaviours) between subjects design. Both risk and crisis communication supported adequate behaviour in a crisis situation. In addition,...

  20. Roadmap on optical security

    javidi, B.; Carnicer, A.; Yamaguchi, M.; Nomura, T.; Pérez-Cabré, E.; Millan, M.S.; Nishchal, N.K.; Torroba, R.; Barrera, J.F.; He, W.; Peng, X.; Stern, A.; Rivenson, Y.; Alfalou, A.; Brosseau, C.; Guo, C.; Sheridan, J.T.; Situ, G.; Naruse, M.; Matsumoto, T.; Juvells, I.; Tajahuerce, E.; Lancis, J.; Chen, W.; Chen, X.; Markman, A.; Mosk, A.P.; Pinkse, P.W.H.
    Information security and authentication are important challenges facing society. Recent attacks by hackers on the databases of large commercial and financial companies have demonstrated that more research and development of advanced approaches are necessary to deny unauthorized access to critical data. Free space optical technology has been investigated by many researchers in information security, encryption, and authentication. The main motivation for using optics and photonics for information security is that optical waveforms possess many complex degrees of freedom such as amplitude, phase, polarization, large bandwidth, nonlinear transformations, quantum properties of photons, and multiplexing that can be combined in many ways...

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