In Variable Friction Tactile Displays, an ultrasonic standing wave can be used to reduce the friction coefficient between a user's finger sliding and a vibrating surface. However, by principle, the effect is limited by a saturation due to the contact mechanics, and very low friction levels require very high vibration amplitudes. Besides, to be effective, the user's finger has to move. We present a device which uses a travelling wave rather than a standing wave. We present a control that allows to realize such a travelling wave in a robust way, and thus can be implemented on various plane surfaces. We show experimentally that the force produced by the travelling wave has two superimposed contributions. The first one is equal to the friction reduction produced by a standing of the same vibration amplitude. The second produces a driving force in the opposite direction of the travelling wave. As a result, the modulation range of the tangential force on the finger can be extended to zero and even negative values. Moreover, the effect is dependant on the relative direction of exploration with regards to the travelling wave, which is perceivable and confirmed by a psycho-physical study.
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http://dx.doi.org/10.1109/TOH.2016.2607200 | DOI Listing |
Mol Biol Cell
December 2024
Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan.
The question of how changes in chemoattractant concentration translate into the chemotactic response of immune cells serves as a paradigm for the quantitative understanding of how cells perceive and process temporal and spatial information. Here, using a microfluidic approach, we analyzed the migration of neutrophil-like HL-60 cells to a traveling wave of the chemoattractants fMLP and leukotriene B4 (LTB4). We found that under a pulsatile wave that travels at a speed of 95 and 170 µm/min, cells move forward in the front of the wave but slow down and randomly orient at the back due to temporal decrease in the attractant concentration.
View Article and Find Full Text PDFAm Heart J
December 2024
Klinik für Herz- und Kreislauferkrankungen, Deutsches Herzzentrum München, Technische Universität München; DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany.
Background: Percutaneous coronary intervention of severely calcified lesions is limited by inadequate stent expansion and poor clinical outcomes. Over the past decade, several devices and techniques have been developed for calcium modification and lesion preparation. Intravascular lithotripsy (IVL) is a novel tool in this context.
View Article and Find Full Text PDFMicrovasc Res
December 2024
Department of Cardiology, University Heart Center, University Hospital and University of Zurich, Zurich, Switzerland; Center for Translational and Experimental Cardiology (CTEC), Department of Cardiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. Electronic address:
Background And Aims: Systemic sclerosis (SSc) is a systemic autoimmune disease, characterized by widespread microvasculopathy and fibrosis. Vascular and endothelial cell changes appear to precede other features of SSc. Retinal vascular analysis is a new, easy-to-use tool for the assessment of retinal microvascular function.
View Article and Find Full Text PDFLancet
December 2024
Department of Medicine I, Agaplesion Markus Hospital, Goethe University, Frankfurt, Germany.
Background: Interleukin-23 inhibition is effective in treating ulcerative colitis. Guselkumab is a dual-acting, human IgG1, interleukin-23p19 subunit inhibitor that potently neutralises interleukin-23 and can bind to CD64. We aimed to evaluate the efficacy and safety of guselkumab as induction and maintenance therapy in patients with ulcerative colitis.
View Article and Find Full Text PDFThe goal of this article is to identify and understand the fundamental role of spatial symmetries in the emergence of undulatory swimming using an anguilliform robot. Here, the local torque at the joints of the robot is controlled by a chain of oscillators forming a central pattern generator (CPG). By implementing a symmetric CPG with respect to the transverse plane, motor activation waves are inhibited, preventing the emergence of undulatory swimming and resulting in an oscillatory gait.
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