Topic
Systems containing self-propelled particles that consume energy to move, such as bacterial suspensions and light-driven synthetic colloids.
IIT Gandhinagar researchers report that enzyme reactions in the fluid around cells raised the cells' uptake of transferrin by roughly 17%. If the team's stirring explanation holds, the medium around a cell helps set how much cargo the cell takes in.
Reality
University of Pittsburgh researchers reversed the direction of the energy cascade in two-dimensional turbulence using one small, correctly angled obstacle. The result loosens the long-held rule that a flow's dimensions alone decide whether energy moves to larger or smaller eddies.
Reality
Yi Hu's group at Nankai University sent a narrow beam against the flow of a broader optical fluid. The swimmer felt attraction while the fluid pushed back, and the net force pointed upstream.
Reality
Standard active nematic theory sends paired defects along straight, mirrored lines. A Ben-Gurion-led team reports in Nature Physics that it measured curved, co-rotating paths in swarming bacteria and in human bronchial cells.
Reality
Heating a gold-coated sphere with tailored light patterns makes the same particle push like a bacterium or pull like an alga. Because the laser can only add heat, the slowest style turned out to be the most efficient.
Reality
Polystyrene spheres of 1 and 1.5 microns in an alternating field pull on each other unequally, pair off with the big one in front, and keep building clusters that break apart again over more than an hour.
Reality
A TIFR and Heinrich Heine simulation study reports that doping a sheared glass with self-propelled particles raises the stress it bears and replaces the single fatal shear band with a network.
Reality