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Microorganisms inspire AI-driven microrobots through their evolved navigation in complex fluids. Authors demonstrate AI-enabled chemotaxis in robotic swimmers using hierarchical reinforcement learning under partial observability.

Controlling molecular transport across immiscible liquid interfaces is vital for applications in biotechnology, manufacturing, and space research. Here, the authors show that unsteady temperature fields drive directional water transport across oil-water interfaces via Marangoni natural convection, enabling tunable, surfactant-free nanoemulsion formation.

The authors reveal that the ocean right above the sloping seafloor flows on average downhill and that this downhill flow recirculates upward in the overlying water column using ocean velocity observations and numerical ocean simulations.

While nanofluidics demonstrate unconventional properties at the nanoscale, large-scale implementation remains challenging. The authors demonstrate macroscale resonant electro-osmotic transport in asymmetric membranes for advanced water filtration applications.

The Surface Water Ocean Topography mission observed week-long earth-shaking waves formed by landslide-induced tsunamis in an East Greenland fjord. Connecting these observations with seismic data confirms their existence and initial characteristics.

Here, the authors demonstrate MorpHoloNet: a physics-driven, coordinate-based deep learning model enabling single-shot reconstruction of 3D morphology and refractive index distribution of biological cells in digital holographic microscopy without angular scanning.

The evolution of phagotrophy by microbes required effective particle transport and ingestion, enabling the rise of ciliates as key grazers in aquatic ecosystems. This study shows that the morphological adaptations of ciliates for phagotrophy were shaped by hydrodynamic forces.

Efficient small-scale fluid capture and transport is essential for point-of-care diagnostics but faces trade-offs between speed, volume, and flow resistance. Inspired by hummingbirds, the proposed elastocapillary device enables rapid, passive fluid capture and aliquoting, combining capillarity and elasticity for optimal performance.

Membrane-free synthetic DNA-based condensates enable programmable control of dynamic behaviors as shown by phase-separated condensates in biological cells. Here, the authors demonstrate remote-controlled microflow using photocontrollable state transitions of DNA condensates, using an azobenzene motif.

Controlling the movement of floating objects at small scales is essential for microfluidics, but traditional methods are limited by fluid and object properties. By shaping liquid interfaces with 3D-printed spines, the study enables programmable manipulation of floating particles for applications like sorting and cleaning.

Extremely high-resolution simulations reveal that interstellar medium-type turbulence significantly deviates from classical magnetized turbulence models.

The self-sustained motion of bacterial suspensions can lead to irregular, highly dynamic vortex patterns, reminiscent of turbulence. Exploring the impact of shear-thinning on these active fluids, the authors predict a non-equilibrium transition between the macroscopically quiescent suspension and mesoscale turbulence, characterized by hysteresis and spatial coexistence.

Accurately estimating the self-motion of fish-like robots in complex environments remains a challenge for current sensing systems based on artificial lateral lines. Here, authors employ a mode decomposition method to estimate the motion states of the robot, enhancing the sensing capabilities of fish-like robotic systems.

How unicellular organisms evolved into multicellular ones is an open question. Now, using unicellular Stentor coeruleus as a model system, the transition between isolated individuals and a coordinated colony is shown to benefit all colony members.

A solid hitting a liquid surface normally creates a region of high pressure at the solid-liquid contact area. Now, it is shown that for a flat-bottomed cylinder hitting a liquid at low-enough impact speed, the local pressure is sufficiently low to cause the liquid to cavitate.

Kinetic energy put into a granular medium as a collective is typically dissipated as friction. The situation is different when forces are applied to the individual particles. An experiment now shows that when torques are applied to particles in a dense bed of microrollers, the grains roll uphill.

In spin hydrodynamic generation originating from the coupling of mechanical rotation in a fluid and electron spin, fluid vorticity can be converted into an electric voltage via a spin current. Here, the authors demonstrate experimentally that the energy conversion in a laminar flow regime is strongly enhanced over the turbulent regime.

The authors describe a dynamic surface instability between impacting materials, showing that a region of mixing grows between two media. The study implies that this can explain mixed compositions and textures in certain meteorites.

Elastoviscoplastic fluids combine solid- and liquid-like behaviour depending on applied stress. Simulations of elastoviscoplastic fluids at high Reynolds number now show that plasticity plays a key role in the turbulent flows seen in these systems, leading for example to intermittency.

Understanding how foams destabilize is key for developing applications. Experiments with foamed oil-in-water emulsions now show that bubble size evolution can be controlled by varying the continuous phase elastic modulus, exploiting the interplay between a foam’s structure and mechanical properties.

The flow features of cell monolayers depend on cellular interactions. Now four different types of cell monolayer are shown to exhibit robust conformal invariance that belongs to the percolation universality class.

Interfacial instabilities can be damaging as they may lead to fabrication defects. Here the authors harness a fluid instability to their advantage to produce thin polymeric films with drop-shaped structures which have tailored geometrical properties.

Elastic deformation of soft substrates occurs upon wetting, yet it is challenging to follow its dynamics at a microscale. Khattak et al. show that the force required to pull a droplet along a soft surface decreases monotonically as the film thickness decreases and explain the phenomenon using a scaling analysis.

Tanner’s law describes the spreading dynamics of droplets made of Newtonian viscous fluids. Here, the authors demonstrate that this law remains valid for phase-separated binary liquids close to their critical point, and thus for all the associated universality class.

Objects moving through fluids and granular media experience drag forces that determine their dynamics. The authors consider the case of multiple objects moving through a low-density granular material and show that their dynamics are cooperative.

Fluidic energy conversion has been proposed as a renewable energy solution, but its conversion efficiency is low to date. Xie et al. improve the efficiency to 48% in a microfluidic electrostatic generator, which converts the kinetic energy of high-speed charged droplets to electricity.

Dispensing small droplets is essential to many ink printing, chemical and biological technologies, but the conventional orifice-based methods fail when the size of droplets approaches sub-micrometre range. Here, Zhang et al.show dispensing of viscous droplets down to attolitre in a controllable way.

Covalency is a fundamental concept in chemical bonding, but experimentally it is not possible to measure the degree of covalency of a particular bond. Here, the authors report a model to link the covalency of hydrogen bonds in water with the anisotropy of the magnetic shielding tensor in the proton NMR.

Superfluids experience drag from container walls and dissipate energy because of quantized vortices and turbulence. Hosio et al. find that in a ³He superfluid at temperatures approaching absolute zero, friction with the walls disappears like in an ideal liquid, while energy dissipation remains finite.

Large methane hydrates reserves are found in mud volcanoes, but climate change may lead to methane release. Here, the authors show that methane adsorption creates overpressures leading to rapid recirculation of seawater, thus reducing the melting timescales of methane hydrates from millennia to decades.

A thin liquid coating on a fibre can break up into droplets due to the Plateau–Rayleigh instability, as for instance on a spider web. Here, Haefner et al. show that the growth rate of the droplet undulations strongly depends on the fibre–liquid boundary condition and slip accelerates the instability.

A physical description of supercritical fluids remains challenging because common approximations for solids and gases do not apply to liquids. Bolmatov et al. identify a liquid/gas dynamic crossover of specific heat above the critical point, and formulate a theory to shed light on its nature.

It is commonly believed that the flow of water or air with large Reynolds number can only have one turbulent state because of large fluctuations. Here, Huisman et al. disprove this theory in experiments by identifying the existence of multiple stable states in highly turbulent Taylor–Couette flow.

Electro-osmosis is the control of fluid motion through application of an electrical field. Here, the authors present a new method of electro-osmosis using electrically conductive liquid crystals, and show tunable electro-osmotic flow using director liquid-crystal patterns.

Water treatment processes mostly rely on the use of membranes and filters, which have high pumping costs and require periodic replacement. Here, the authors describe an efficient membraneless method that induces directed motion of suspended colloidal particles by exposing the suspension to CO₂.

A better understanding of many environmental phenomena, such as plankton spreading in the ocean, relies on knowledge of the dispersion statistics. Xia et al. trace particles' trajectories in laboratory turbulence and reveal that a single force scale can be sufficient to predict the dispersion of particles.

Controlling liquids at small scales is of importance for applications in microfluidics. Ortiz-Young et al.show that shear forces in nanoconfined water change dramatically if the confining surface is either hydrophobic or hydrophilic, offering a new understanding of the flow of liquids on the nanoscale.

A bubble at an air–liquid interface can form a liquid jet upon bursting, spraying aerosol droplets into the air. Leeet al. show that jetting is analogous to pinching-off in liquid coalescence, which may be useful in applications that prevent jet formation and in the improved incorporation of aerosols in climate models.

Electron transfer from solute to solvent has a crucial role in chemistry, but this process has not yet been visualized in real time. Messina et al.provide the first real-time observation of the dynamic rearrangement of water cages around aqueous halides before full electron ejection.

Glasses are known to have very slow flow behaviour on application of force, but the structural basis for this flow is currently unclear. Here Wang et al.use a dynamic mechanical analysis to study the flow phenomena in a La-based metallic glass.

Many biological reactions typically occur in a fluid that is near to a surface. Here, the authors apply theory used to describe glassy systems to quantitatively understand these effects, finding that correlated particle motion near the interface leads to an increase in fluid viscosity.