TY  - CHAP
A1  - Baader, Fabian
A1  - Reiswich, M.
A1  - Bartsch, M.
A1  - Keller, D.
A1  - Tiede, E.
A1  - Keck, G.
A1  - Demircian, A.
A1  - Friedrich, M.
A1  - Dachwald, Bernd
A1  - Schüller, K.
A1  - Lehmann, R.
A1  - Chojetzki, R.
A1  - Durand, C.
A1  - Rapp, L.
A1  - Kowalski, Julia
A1  - Förstner, R.
T1  - VIPER - Student research on extraterrestrical ice penetration technology
T2  - Proceedings of the 2nd Symposium on Space Educational Activities
N2  - Recent analysis of scientific data from Cassini and earth-based observations gave evidence for a global ocean under a surrounding solid ice shell on Saturn's moon Enceladus. Images of Enceladus' South Pole showed several fissures in the ice shell with plumes constantly exhausting frozen water particles, building up the E-Ring, one of the outer rings of Saturn. In this southern region of Enceladus, the ice shell is considered to be as thin as 2 km, about an order of magnitude thinner than on the rest of the moon. Under the ice shell, there is a global ocean consisting of liquid water. Scientists are discussing different approaches the possibilities of taking samples of water, i.e. by melting through the ice using a melting probe. FH Aachen UAS developed a prototype of maneuverable melting probe which can navigate through the ice that has already been tested successfully in a terrestrial environment. This means no atmosphere and or ambient pressure, low ice temperatures of around 100 to 150K (near the South Pole) and a very low gravity of 0,114 m/s^2 or 1100 μg. Two of these influencing measures are about to be investigated at FH Aachen UAS in 2017, low ice temperature and low ambient pressure below the triple point of water. Low gravity cannot be easily simulated inside a large experiment chamber, though. Numerical simulations of the melting process at RWTH Aachen however are showing a gravity dependence of melting behavior. Considering this aspect, VIPER provides a link between large-scale experimental simulations at FH Aachen UAS and numerical simulations at RWTH Aachen. To analyze the melting process, about 90 seconds of experiment time in reduced gravity and low ambient pressure is provided by the REXUS rocket. In this time frame, the melting speed and contact force between ice and probes are measured, as well as heating power and a two-dimensional array of ice temperatures. Additionally, visual and infrared cameras are used to observe the melting process.
Y1  - 2018
SP  - 1
EP  - 6
ER  - 
TY  - JOUR
A1  - Ringers, Christa
A1  - Bialonski, Stephan
A1  - Ege, Mert
A1  - Solovev, Anton
A1  - Hansen, Jan Niklas
A1  - Jeong, Inyoung
A1  - Friedrich, Benjamin M.
A1  - Jurisch-Yaksi, Nathalie
T1  - Novel analytical tools reveal that local synchronization of cilia coincides with tissue-scale metachronal waves in zebrafish multiciliated epithelia
JF  - eLife
N2  - Motile cilia are hair-like cell extensions that beat periodically to generate fluid flow along various epithelial tissues within the body. In dense multiciliated carpets, cilia were shown to exhibit a remarkable coordination of their beat in the form of traveling metachronal waves, a phenomenon which supposedly enhances fluid transport. Yet, how cilia coordinate their regular beat in multiciliated epithelia to move fluids remains insufficiently understood, particularly due to lack of rigorous quantification. We combine experiments, novel analysis tools, and theory to address this knowledge gap. To investigate collective dynamics of cilia, we studied zebrafish multiciliated epithelia in the nose and the brain. We focused mainly on the zebrafish nose, due to its conserved properties with other ciliated tissues and its superior accessibility for non-invasive imaging. We revealed that cilia are synchronized only locally and that the size of local synchronization domains increases with the viscosity of the surrounding medium. Even though synchronization is local only, we observed global patterns of traveling metachronal waves across the zebrafish multiciliated epithelium. Intriguingly, these global wave direction patterns are conserved across individual fish, but different for left and right noses, unveiling a chiral asymmetry of metachronal coordination. To understand the implications of synchronization for fluid pumping, we used a computational model of a regular array of cilia. We found that local metachronal synchronization prevents steric collisions, i.e., cilia colliding with each other, and improves fluid pumping in dense cilia carpets, but hardly affects the direction of fluid flow. In conclusion, we show that local synchronization together with tissue-scale cilia alignment coincide and generate metachronal wave patterns in multiciliated epithelia, which enhance their physiological function of fluid pumping.
Y1  - 2023
U6  - http://dx.doi.org/10.7554/eLife.77701
SN  - 2050-084X
VL  - 12
PB  - eLife Sciences Publications
ER  - 
TY  - INPR
A1  - Ringers, Christa
A1  - Bialonski, Stephan
A1  - Solovev, Anton
A1  - Hansen, Jan N.
A1  - Ege, Mert
A1  - Friedrich, Benjamin M.
A1  - Jurisch-Yaksi, Nathalie
T1  - Preprint: Local synchronization of cilia and tissue-scale cilia alignment are sufficient for global metachronal waves
T2  - bioRxiv
N2  - Motile cilia are hair-like cell extensions present in multiple organs of the body. How cilia coordinate their regular beat in multiciliated epithelia to move fluids remains insufficiently understood, particularly due to lack of rigorous quantification. We combine here experiments, novel analysis tools, and theory to address this knowledge gap. We investigate collective dynamics of cilia in the zebrafish nose, due to its conserved properties with other ciliated tissues and its superior accessibility for non-invasive imaging. We revealed that cilia are synchronized only locally and that the size of local synchronization domains increases with the viscosity of the surrounding medium. Despite the fact that synchronization is local only, we observed global patterns of traveling metachronal waves across the multiciliated epithelium. Intriguingly, these global wave direction patterns are conserved across individual fish, but different for left and right nose, unveiling a chiral asymmetry of metachronal coordination. To understand the implications of synchronization for fluid pumping, we used a computational model of a regular array of cilia. We found that local metachronal synchronization prevents steric collisions and improves fluid pumping in dense cilia carpets, but hardly affects the direction of fluid flow. In conclusion, we show that local synchronization together with tissue-scale cilia alignment are sufficient to generate metachronal wave patterns in multiciliated epithelia, which enhance their physiological function of fluid pumping.
Y1  - 2021
U6  - http://dx.doi.org/10.1101/2021.11.23.469646
N1  - Veröffentlicht in eLife 12:e77701 (https://doi.org/10.7554/eLife.77701).
ER  -