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University of Twente Publications (57.737 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 26.438

  1. Gebruik van een ambulante activiteitencoach om mensen met COPD te motiveren tot een actieve levensstijl

    Vos-Maneschijn, Linda; Tabak, Monique; Akker, Harm op den; Hermens, Hermie
    Het stimuleren van een actieve levensstijl is een belangrijk aspect in de behandeling van patiënten met COPD. Het toepassen van telemedicine kan hieraan een waardevolle bijdrage leveren, doordat zij inzicht geven in het dagelijks activiteitengedrag en de patiënt kunnen coachen om dit gedrag te verbeteren in het dagelijks leven. In dit artikel, gebaseerd op een onderzoek dat is uitgevoerd bij Roessingh Research and Development in Esnchede in het kader van de afstudeerthesis Master Fysiotherapie bij mensen met chronische ziekten aan de Hogeschool Leiden, wordt inzichtelijk gemaakt hoe COPD patiënten kunnen worden gemotiveerd tot een actieve levensstijl door het gebruik van...

  2. Balance Asymmetry in Parkinson's Disease and Its Contribution to Freezing of Gait

    Boonstra, T.A.; Vugt, J.P.P. van; Kooij, H. van der; Bloem, B.R.
    Balance control (the ability to maintain an upright posture) is asymmetrically controlled in a proportion of patients with Parkinson’s disease. Gait asymmetries have been linked to the pathophysiology of freezing of gait. We speculate that asymmetries in balance could contribute to freezing by a) hampering the unloading of the stepping leg and/or b) leading to a preferred stance leg during gait, which then results in asymmetric gait. To investigate this, we examined the relationship between balance control and weight-bearing asymmetries and freezing. We included 20 human patients with Parkinson (tested OFF medication; nine freezers) and nine healthy controls. Balance was...

  3. Assessment of the relation between initial culprit vessel patency in acute ST-elevation myocardial infarction and endothelial function

    Kandhai-Ragunath, J.; Jorstad, Harald T.; Wagenaar, Bjorn de; Man, Frits H.A.F. de; Stoel, Martin G.; Es, Jan van; Doelman, Cees J.A.; Doggen, Carine J.M.; Peters, Ron J.G.; Birgelen, Clemens von
    Aims: To assess whether better endothelial function increases the likelihood of patients with acute ST-elevation myocardial infarction (STEMI) having initially patent culprit vessels. Clinical data on the relation between endothelial function and culprit vessel patency in STEMI patients are scarce. Methods and results: In this prospective cohort study in 71 patients with STEMI, endothelial function was non-invasively assessed by use of the reactive hyperaemia peripheral artery tonometry (RH-PAT) method at four to six weeks after the primary percutaneous coronary intervention (PPCI). The RH-PAT index measured on average 1.90±0.58. In patients with patent culprit vessels before PPCI (n=33, 46.5%), endothelial function was significantly better...

  4. Precise localization and control of catalytic Janus micormotors using weak magnetic fields

    Khalil, Islam S.M.; Magdanz, Veronika; Sanchez, Samuel; Schmidt, Oliver G.; Misra, Sarthak
    We experimentally demonstrate the precise localization of spherical Pt-Silica Janus micromotors (diameter 5 µm) under the influence of controlled magnetic fields. First, we control the motion of the Janus micromotors in two-dimensional (2D) space. The control system achieves precise localization within an average region-of-convergence of 7 µm. Second, we show that these micromotors provide sufficient propulsion force, allowing them to overcome drag and gravitational forces and move both downwards and upwards. This propulsion is studied by moving the micromotors in three-dimensional (3D) space. The micromotors move downwards and upwards at average speeds of 19.1 µm/s and 9.8 µm/s, respectively. Moreover,...

  5. Spectrum efficient, localized, orthogonal waveforms: closing the gap with the Balian-low theorem

    Korevaar, C. Willem; Kokkeler, André B.J.; Boer, Pieter-Tjerk de; Smit, Gerard J.M.
    The Balian-Low theorem (BLT) states the fundamental impossibility to design waveforms for L2(ℝ), which 1) form an orthogonal set, 2) are time-frequency localized, and 3) attain a critical waveform density such that they form an orthogonal basis. This article closes the gap between existing waveform designs and the BLT. The main contribution is the design of orthogonal, time-frequency localized, spectrum efficient waveforms for hexagonal lattices. The waveform design is adaptive by a single design parameter, which trades off time-frequency localization with the waveform density. As the orthogonalization procedure is based on employing the minimum number of most time-frequency localized waveforms...

  6. Psychometric Characteristics of a Patient Reported Outcome Measure on Ego-Integrity and Despair among Cancer Patients

    Kleijn, Gitta; Post, Lenneke; Witte, Birgit I.; Bohlmeijer, Ernst T.; Westerhof, Gerben J.; Cuijpers, Pim; Verdonck-de Leeuw, Irma
    Purpose To evaluate psychometric characteristics of a questionnaire (the Northwestern Ego-integrity Scale (NEIS)) on ego-integrity (the experience of wholeness and meaning in life, even in spite of negative experiences) and despair (the experience of regret about the life one has led, and feelings of sadness, failure and hopelessness) among cancer patients. Methods Cancer patients (n = 164) completed patient reported outcome measures on ego-integrity and despair (NEIS), psychological distress, anxiety and depression (Hospital Anxiety and Depression Scale (HADS)), and quality of life (EORTC QLQ-C30 (cancer survivors, n = 57) or EORTC QLQ-C15-PAL (advanced cancer patients, n = 107)). Confirmatory Factor Analysis was used...

  7. Catching a Deceiver in the Act: Processes Underlying Deception in an Interactive Interview Setting

    Ströfer, Sabine; Ufkes, Elze G.; Noordzij, Matthijs L.; Giebels, Ellen
    Lying is known to evoke stress and cognitive load. Both form cues to deception and lead to an increase in sympathetic nervous system (SNS) activity. But in reality, deceivers stick to the truth most the time and only lie occasionally. The present study therefore examined in an interactive suspect interview setting, whether deceivers still have clearly diverging cognitive and emotional processes from truth tellers when only having the intention to lie incidentally. We found that deceivers who lied constantly diverge from truth tellers in SNS activity, self-reported cognitive load and stress. Across all interviews, SNS activity correlated stronger with self-reports...

  8. How and for whom does web-based acceptance and commitment therapy work? Mediation and moderation analyses of web-based ACT for depressive symptoms

    Pots, Wendy T.M.; Trompetter, Hester R.; Schreurs, Karlein M.G.; Bohlmeijer, Ernst T.
    Background Acceptance and Commitment Therapy (ACT) has been demonstrated to be effective in reducing depressive symptoms. However, little is known how and for whom therapeutic change occurs, specifically in web-based interventions. This study focuses on the mediators, moderators and predictors of change during a web-based ACT intervention. Methods Data from 236 adults from the general population with mild to moderate depressive symptoms, randomized to either web-based ACT (n = 82) or one of two control conditions (web-based Expressive Writing (EW; n = 67) and a waiting list (n = 87)), were analysed. Single and multiple mediation analyses, and exploratory linear regression analyses were performed using PROCESS and linear regression...

  9. Commentary: Patients as Partners: Building on the Experience of Outcome Measures in Rheumatology

    Kirwan, John R.; Wit, Maarten P.T. de; Bingham III, Clifton O.; Leong, Amye; Richards, Pamela; Tugwell, Peter S.; Voshaar, Marieke; Gossec, Laure

  10. Contemporary Locoregional Recurrence Rates in Young Patients With Early-Stage Breast Cancer

    Aalders, Kim C.; Postma, Emily L.; Strobbe, Luc J.; Heiden-van der Loo, Margriet van der; Sonke, Gabe S.; Boersma, Liesbeth J.; Diest, Paul J. van; Siesling, Sabine; Dalen, Thijs van
    Purpose The aim of this study was to evaluate contemporary rates of local recurrence (LR) and regional recurrence (RR) in young patients with breast cancer in relation to tumor biology as expressed by biomarker subtypes. Patients and Methods Women < 35 years of age who underwent surgery for primary unilateral invasive breast cancer between 2003 and 2008 were selected from the Netherlands Cancer Registry. Patients were categorized according to biomarker subtypes on the basis of hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. The 5-year risks of developing LR and regional lymph node recurrence were estimated...

  11. Does sensitivity in binary choice tasks depend on response modality?

    Szumska, Izabela; Lubbe, Rob H.J. van der; Grzeczkowski, Lukasz; Herzog, Michael H.
    In most models of vision, a stimulus is processed in a series of dedicated visual areas, leading to categorization of this stimulus, and possible decision, which subsequently may be mapped onto a motor-response. In these models, stimulus processing is thought to be independent of the response modality. However, in theories of event coding, common coding, and sensorimotor contingency, stimuli may be very specifically mapped onto certain motor-responses. Here, we compared performance in a shape localization task and used three different response modalities: manual, saccadic, and verbal. Meta-contrast masking was employed at various inter-stimulus intervals (ISI) to manipulate target visibility. Although...

  12. Spillovers and conflict in wage bargaining: Experimental evidence

    Lehr, Alex; Vyrastekova, Jana; Akkerman, Agnes; Torenvlied, Rene
    We investigate how information spillovers from other negotiations affect conflict in bargaining. Two theoretical mechanisms are studied: (1) social comparisons, which are hypothesized to increase conflict due to self-serving biases, and (2) rational learning, which is hypothesized to decrease conflict by reducing information asymmetries. Our experimental design allows for an interactive bargaining process and offers full control over the information available to negotiators. Consistent with studies of one-shot games, we find that spillovers resulting from social comparisons increase conflict; however, the bargaining process mitigates this effect. In bargaining situations in which spillovers also allow for rational learning, the conflict-increasing effects...

  13. Treininformatie: onderhoudstoestand realtime bijhouden

    Dongen, Leo A.M. van
    Afgelopen maand is de NS begonnen met het testen van de nieuwe sprinter, de Flirt. Het is het eerste treintype dat van begin af aan zijn onderhoudstoestand realtime bijhoudt. ‘De toekomst is dat de trein zelf zijn werkbon voor de werkplaats opstelt

  14. Intuitive control of self-propelled microjets with haptic feedback

    Pacchierotti, C.; Magdanz, V.; Medina-Sanchez, M.; Schmidt, O.G.; Prattichizzo, D.; Misra, S.

  15. Integrated microwave photonic splitter with reconfigurable amplitude, phase, and delay offsets

    Zhuang, Leimeng; Burla, Maurizio; Taddei, Caterina; Roeloffzen, Chris G.H.; Hoekman, Marcel; Leinse, Arne; Boller, Klaus-J.; Lowery, Arthur J.
    This work presents an integrated microwave photonics splitter with reconfigurable amplitude, phase, and delay offsets. The core components for this function are a dual-parallel Mach–Zehnder modulator, a deinterleaver, and tunable delay lines, all implemented using photonic integrated circuits. Using a demonstrator with an optical free spectral range of 25 GHz, we show experimentally the RF splitting function over two continuous bands, i.e., 0.9–11.6 GHz and 13.4–20 GHz. This result promises a deployable solution for creating wideband, reconfigurable RF splitters in integrated forms.

  16. Importance of circulating tumor cells in newly diagnosed colorectal cancer

    Dalum, Guus van; Stam, Gerrit-Jan; Scholten, Loes F.A.; Mastboom, Walter J.B.; Vermes, István; Tibbe, Arjan G.J.; De Groot, Marco R.; Terstappen, Leon W.M.M.
    Presence of circulating tumor cells (CTC) is associated with poor prognosis in patients with metastatic colorectal cancer (CRC). The present study was conducted to determine if the presence of CTC prior to surgery and during follow‑up in patients with newly diagnosed non-metastatic CRC can identify patients at risk for disease recurrence. In a prospective single center study 183 patients with newly diagnosed non-disseminated CRC, scheduled for surgery, were enrolled and followed-up for a median of 5.1 years. CTC were enumerated with the CellSearch system in 4 aliquots of 7.5 ml of blood before surgery and at several time-points during follow-up...

  17. A new view on the metastable zone width during cooling crystallization

    Kadam, Somnath S.; Kulkarni, Samir A.; Coloma Ribera, Roger; Stankiewicz, Andrzej I.; Horst, Joop H. ter; Kramer, Herman J.M.
    The Metastable Zone Width (MSZW) is the difference between the saturation temperature and the temperature at which crystals are detected under constant cooling rate. The MSZW is conventionally treated as a reproducible, deterministic, volume independent property and is commonly used to characterize crystal nucleation and to determine the crystallization process operation window. In this paper we investigate the volume dependency of the MSZW both experimentally and theoretically. MSZW measurements were performed for paracetamol–water and isonicotinamide–ethanol model systems at four different volumes between 500 mL and 1 L. A stochastic model developed based on the Single Nucleus Mechanism and a deterministic...

  18. Dependence of nociceptive detection thresholds on physiological parameters and capsaicin-induced neuroplasticity: a computational study

    Yang, Huan; Meijer, Hil G.E.; Doll, Robert J.; Buitenweg, Jan R.; Gils, Stephan A. van
    Physiological properties of peripheral and central nociceptive subsystems can be altered over time due to medical interventions. The effective change for the whole nociceptive system can be reflected in changes of psychophysical characteristics, e.g., detection thresholds. However, it is challenging to separate contributions of distinct altered mechanisms with measurements of thresholds only. Here, we aim to understand how these alterations affect Aδ-fiber-mediated nociceptive detection of electrocutaneous stimuli. First, with a neurophysiology-based model, we study the effects of single-model parameters on detection thresholds. Second, we derive an expression of model parameters determining the functional relationship between detection thresholds and the interpulse...

  19. Initialization of Homoclinic Solutions near Bogdanov-Takens Points: Lindstedt-Poincaré Compared with Regular Perturbation Method

    Al-Hdaibat, B.; Govaerts, W.; Kouznetsov, Yu.A.; Meijer, H.G.E.
    To continue a branch of homoclinic solutions starting from a Bogdanov-Takens (BT) point in parameter and state space, one needs a predictor based on asymptotics for the bifurcation parameter values and the corresponding small homoclinic orbits in the phase space. We derive two explicit asymptotics for the homoclinic orbits near a generic BT point. A recent generalization of the Lindstedt-Poincaré (L-P) method is applied to approximate a homoclinic solution of a strongly nonlinear autonomous system that results from blowing up the BT normal form. This solution allows us to derive an accurate second-order homoclinic predictor to the homoclinic branch rooted...

  20. Plasticity and fracture modeling of the heat-affected zone in resistance spot welded tailor hardened boron steel

    Eller, T.K.; Greve, L.; Andres, M.T.; Medricky, M.; Geijselaers, H.J.M.; Meinders, V.T.; Boogaard, A.H. van den
    tFive hardness grades of 22MnB5 are considered, covering the full strength-range from 600 MPa in theferritic/pearlitic range to 1500 MPa in the fully hardened, martensitic state. These five grades form thebasis for a hardness-based material model for the heat-affected zone found around resistance spot weldsin tailor hardened boron steel. Microhardness measurements of resistance spot welds in all five gradesare used to determine the location and shape of the heat-affected zone and for mapping of the hardnessdistributions into FE-models of the specimens used for model calibration. For calibration of the strainhardening of the heat-affected zone, a specially designed asymmetric uni-axial tensile...

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