Motivated by the observed coordination of nearby beating cilia, we use a scale model experiment to show that hydrodynamic interactions can cause synchronization between rotating paddles driven at constant torque in very viscous fluid. Synchronization is only when shafts supporting have some flexibility. The phase difference synchronized state depends on symmetry paddles. We method regularized stokeslets and find excellent agreement with experimental observations. also simple analytic theory...

The swimming behaviour of microorganisms can be strongly influenced by the rheology their fluid environment. In this manuscript, we experimentally investigate effects shear-thinning viscosity on an undulatory swimmer, nematode Caenorhabditis elegans. Tracking methods are used to measure swimmer's kinematic data (including propulsion speed) and velocity fields. We find that modifies fields produced but does not modify nematode's speed beating kinematics. Velocimetry show significant...

Droplet deposition onto a hydrophobic surface is studied experimentally and numerically. A wide range of droplet sizes can result from the same syringe, depending strongly on needle retraction speed. Three regimes are identified according to motion contact line. In region I, at slow speeds, line expands large droplets be achieved. II, moderate quasicylindrical liquid bridge forms resulting in drops approximately size needle. Finally, high speeds (region III), retracts much smaller than...

Numerous natural processes are contingent on microorganisms' ability to swim through fluids with non-Newtonian rheology. Here, we use the model organism Caenorhabditis elegans and tracking methods experimentally investigate dynamics of undulatory swimming in shear-thinning fluids. Theory simulation have proposed that cost swimming, or mechanical power, should be lower a fluid compared Newtonian same zero-shear viscosity. We aim provide an experimental investigation into from (i) estimate...

An enticing feature of active materials is the possibility controlling macroscale rheological properties through activity microscopic constituents. Using a unique combination microscopy and rheology we study three dimensional microtubule-based whose autonomous flows are powered by continually rearranging connected network. We quantify relationship between dynamics bulk mechanical these nonequilibrium networks. Experiments reveal surprising nonmonotonic viscosity that strongly depends on...

The motility behavior of the nematode Caenorhabditis elegans in polymeric solutions varying concentrations is systematically investigated experiments using tracking and velocimetry methods. As polymer concentration increased, solution undergoes a transition from semi-dilute to concentrated regime, where these rod-like polymers entangle, align, form networks. Remarkably, we find an enhancement nematode's swimming speed approximately 65% compared solutions. Using methods, show that undulatory...

Swimming cells and microorganisms are a critical component of many biological processes. In order to better interpret experimental studies low Reynolds number swimming, we combine numerical methods perform an analysis the flow-field around swimming nematode Caenorhabditis elegans. We first use image processing particle tracking velocimetry extract body shape, kinematics, flow-fields nematode. then construct three-dimensional model using kinematics employ boundary element method simulate...

Abstract Spinal muscular atrophy (SMA) is a neuromuscular disease characterized by degeneration of spinal motor neurons resulting in variable degrees wasting and weakness. It caused loss-of-function mutation the survival neuron ( SMN1 ) gene. Caenorhabditis elegans mutants lacking SMN recapitulate several aspects including impaired movement shorted life span. We examined whether genes previously implicated span extension conferred benefits to C. SMN. find that reducing daf-2/insulin receptor...

In the absence of inertia, a reciprocal swimmer achieves no net motion in viscous Newtonian fluid. Here, using tracking methods and birefringence imaging, we investigate ability reciprocally actuated particle to translate through complex fluid that possesses network. A geometrically polar particle, rod with bead on one end, is rotated magnetic fields. The immersed wormlike micellar (WLM) solution known be susceptible formation shear bands other localized structures due shear-induced...

We evaluated the alpha-helix content, biological activities and affinities of a series neuropeptide Y (NPY) analogs containing structural alterations, mainly in central portion molecule for which putative arrangement has been proposed. First, we investigated conformational pharmacological characteristics derivatives N-terminal tetrapeptide linked to C-terminal peptide-amide segments various lengths. In some these, missing was replaced with epsilon-aminocaproic acid, flexible arm-linker. Data...

Deicing and anti-icing the aircraft using proper chemical fluids, prior takeoff, are mandatory. A thin layer of ice or snow can compromise safety, causing lift loss drag increase. Commercialized deicing fluids all pass a qualification process which is described in Society Automotive Engineering (SAE) documents. Most them endurance time tests under freezing frozen contaminants, simulated natural conditions. They have common that times to be determined by visual inspection. When certain...

Abstract The ability of microbes to attach biological and inert substrates is a necessary prerequisite for colonization new habitats. In contrast well-characterized mechanisms that rely on specific or non-specific chemical interactions between microbe substrate, we describe here an effective hydrodynamic mechanism attachment relies fluid flow generated by the microbe. Giardia lamblia , flagellated protozoan parasite, naturally attaches microvilliated surface small intestine but also capable...

The ability of microbes to attach biological and inert substrates is a necessary prerequisite for colonization new habitats. In contrast well-characterized mechanisms that rely on specific or nonspecific chemical interactions between microbe substrate, we describe here an effective hydrodynamic mechanism attachment relies fluid flow generated by the microbe. Giardia lamblia, flagellated protozoan parasite, naturally attaches microvilliated surface small intestine but also capable attaching...

We experimentally investigate the effects of polymer additives on collective dynamics swarming Serratia marcescens in quasi two-dimensional (2D) liquid films. find that even minute amounts polymers (< 20 ppm) can significantly enhance swimming speed and promote largescale coherent structures. Velocity statistics show suppress large velocity fluctuation, transforming distributions from super-Gaussian to Gaussian. Spatial temporal correlation functions suggest increase both size lifetime flow...

Microscale propulsion is integral to numerous biomedical systems, including biofilm formation and human reproduction, where the surrounding fluids comprise suspensions of polymers. These polymers endow fluid with non-Newtonian rheological properties, such as shear-thinning viscoelasticity. Thus, complex dynamics present modelling challenges. Here, we demonstrate that neglecting ‘out-of-plane’ effects during swimming through a results in significant overestimate viscosity around undulatory...

Microscale propulsion is integral to numerous biomedical systems, including biofilm formation and human reproduction, where the surrounding fluids comprise suspensions of polymers. These polymers endow fluid with non-Newtonian rheological properties, such as shear-thinning viscoelasticity. Thus, complex dynamics present modelling challenges. Here, we demonstrate that neglecting `out-of-plane’ effects during swimming through a results in significant overestimate viscosity around undulatory...

T.D.M.-J. is supported by a Royal Commission for the Exhibition of 1851 Research Fellowship and D.A.G. an NSF Graduate Fellowship. Funding from European Union (CIG Grant to E.L.) NSF-CBET-1437482 (to P.E.A.) gratefully acknowledged.