Now showing items 1-20 of 44

    • Aberrant cerebral network topology and mild cognitive impairment in early Parkinson’s disease 

      Pereira, J. B.; Aarsland, D.; Ginestet, C. E.; Lebedev, A. V.; Wahlund, L. O.; Simmons, A.; Volpe, G.; Westman, E. (John Wiley & Sons, Inc., 2015-05-06)
      The aim of this study was to assess whether mild cognitive impairment (MCI) is associatedwith disruption in large-scale structural networks in newly diagnosed, drug-na€ıve patients with Parkin-son’s disease (PD). Graph ...
    • Active Brownian motion tunable by light 

      Buttinoni, I.; Volpe, G.; Kümmel, F.; Volpe, G.; Bechinger, C. (Institute of Physics Publishing, 2012)
      Active Brownian particles are capable of taking up energy from their environment and converting it into directed motion; examples range from chemotactic cells and bacteria to artificial micro-swimmers. We have recently ...
    • Active matter alters the growth dynamics of coffee rings 

      Andaç, Tuğba; Weigmann, Pascal; Velu, Sabareesh K. P.; Pinçe, Erçağ; Volpe, G.; Volpe, Giovanni; Callegar, Agnese (Royal Society of Chemistry, 2019)
      How particles are deposited at the edge of evaporating droplets, i.e. the coffee ring effect, plays a crucial role in phenomena as diverse as thin-film deposition, self-assembly, and biofilm formation. Recently, microorganisms ...
    • Active matter alters the growth dynamics of coffee rings 

      Callegari, Agnese; Andaç, Tuğba; Weigmann, Pascal; Velu, Sabareesh K. P.; Pinçe, Erçağ; Volpe, G.; Volpe, Giovanni (OSA, 2018)
      We show that bacterial mobility starts playing a major role in determining the growth dynamics of the edge of drying droplets, as the droplet evaporation rate slows down.
    • Active particles in complex and crowded environments 

      Bechinger, C.; Di Leonardo, R.; Löwen, H.; Reichhardt, C.; Volpe, G. (American Physical Society, 2016-11)
      Differently from passive Brownian particles, active particles, also known as self-propelled Brownian particles or microswimmers and nanoswimmers, are capable of taking up energy from their environment and converting it ...
    • Anisotropic dynamics of a self-assembled colloidal chain in an active bath 

      Aporvari, Mehdi Shafiei; Utkur, Mustafa; Sarıtaş, Emine Ülkü; Volpe, G.; Stenhammar, J. (Royal Society of Chemistry, 2020)
      Anisotropic macromolecules exposed to non-equilibrium (active) noise are very common in biological systems, and an accurate understanding of their anisotropic dynamics is therefore crucial. Here, we experimentally investigate ...
    • Better stability with measurement errors 

      Argun, A.; Volpe, G. (Springer New York LLC, 2016-06)
      Often it is desirable to stabilize a system around an optimal state. This can be effectively accomplished using feedback control, where the system deviation from the desired state is measured in order to determine the ...
    • BRAPH: A graph theory software for the analysis of brain connectivity 

      Mijalkov, M.; Kakaei, E.; Pereira, J. B.; Westman, E.; Volpe, G. (Public Library of Science, 2017)
      The brain is a large-scale complex network whose workings rely on the interaction between its various regions. In the past few years, the organization of the human brain network has been studied extensively using concepts ...
    • Circular motion of asymmetric self-propelling partciles 

      Kummel, F.; Hagen, B.; Wittkowski, R.; Buttinoni, I.; Eichhorn, R.; Volpe, G.; Lowen, H.; Bechinger, C. (American Physical Society, 2013-05-09)
      Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft ...
    • Computational toolbox for optical tweezers in geometrical optics 

      Callegari, A; Mijalkov, M; Gököz, A. B.; Volpe, G. (Optical Society of America, 2014-03-04)
      Optical tweezers have found widespread application in many fields, from physics to biology. Here, we explain in detail how optical forces and torques can be described within the geometrical optics approximation, and we ...
    • Controlling active brownian particles in complex settings 

      Velu, Sabareesh K. P.; Pinçe, Erçağ; Callegari, Agnese; Elahi, Parviz; Gigan, S.; Volpe, Giovanni; Volpe, G. (OSA, 2017)
      We show active Brownian particles (passive Brownian particles in a bacterial bath) switches between two long-term behaviors, i.e. gathering and dispersal of individuals, in response to the statistical properties of the ...
    • A critical microscopic engine in an optical tweezers 

      Schmidt, F.; Magazzù, Agnese; Callegari, A.; Biancofiore, Luca; Cichos, F.; Volpe, G. (OSA, 2018)
      An optically trapped absorbing microsphere in a sub-critical mixture rotates around the optical trap thanks to diffusiophoretic propulsion, which can be controlled by adjusting the optical power, the temperature, and the ...
    • Disorder-mediated crowd control in an active matter system 

      Pinçe, E.; Velu, S. K. P.; Callegari, A.; Elahi, P.; Gigan, S.; Volpe, G.; Volpe, G. (Nature Publishing Group, 2016)
      Living active matter systems such as bacterial colonies, schools of fish and human crowds, display a wealth of emerging collective and dynamic behaviours as a result of far-from-equilibrium interactions. The dynamics of ...
    • Disrupted network topology in patients with stable and progressive mild cognitive impairment and alzheimer's disease 

      Pereira, J. B.; Mijalkov, M.; Kakaei, E.; Mecocci, P.; Vellas, B.; Tsolaki, M.; Kłoszewska, I.; Soininen, H.; Spenger, C.; Lovestone, S.; Simmons, A.; Wahlund, L.-O.; Volpe, G.; Westman, E. (Oxford University Press, 2016)
      Recent findings suggest that Alzheimer's disease (AD) is a disconnection syndrome characterized by abnormalities in large-scale networks. However, the alterations that occur in network topology during the prodromal stages ...
    • Effective drifts in dynamical systems with multiplicative noise: a review of recent progress 

      Volpe, G.; Wehr, J. (Institute of Physics Publishing, 2016)
      Noisy dynamical models are employed to describe a wide range of phenomena. Since exact modeling of these phenomena requires access to their microscopic dynamics, whose time scales are typically much shorter than the ...
    • Engineering particle trajectories in microfluidic flows using speckle light fields 

      Volpe, G.; Volpe, Giovanni; Gigan, S. (SPIE, 2014)
      Optical tweezers have been widely used in physics, chemistry and biology to manipulate and trap microscopic and nanoscopic objects. Current optical trapping techniques rely on carefully engineered setups to manipulate ...
    • Engineering sensorial delay to control phototaxis and emergent collective behaviors 

      Mijalkov, M.; McDaniel, A.; Wehr, J.; Volpe, G. (American Physical Society, 2016-01)
      Collective motions emerging from the interaction of autonomous mobile individuals play a key role in many phenomena, from the growth of bacterial colonies to the coordination of robotic swarms. For these collective behaviors ...
    • Formation, compression and surface melting of colloidal clusters by active particles 

      Kümmel, F.; Shabestari, P.; Lozano, C.; Volpe, G.; Bechinger, C. (Royal Society of Chemistry, 2015)
      We demonstrate with experiments and numerical simulations that the structure and dynamics of a suspension of passive particles is strongly altered by adding a very small (<1%) number of active particles. With increasing ...
    • Kümmel et al. Reply 

      Kümmel, F.; Hagen, B. T.; Wittkowski, R.; Takagi, D.; Takagi, I.; Eichhorn, R.; Volpe, G.; Löwen, H.; Bechinger, C. (American Physical Society, 2014-05-19)
    • Long-term influence of fluid inertia on the diffusion of a Brownian particle 

      Pesce, G.; Volpe, G.; Volpe, G.; Sasso, A. (American Physical Society, 2014)
      We experimentally measure the effects of fluid inertia on the diffusion of a Brownian particle at very long time scales. In previous experiments, the use of standard optical tweezers introduced a cutoff in the free diffusion ...