In the household appliance industry, heat pump systems have been used for a long time in refrigerators and freezers to cool food, and the industry has driven the development of small, high-quality, low-price heat pump components. The low price of good quality heat pump components, along with an increased willingness by customers to pay extra for lower electricity consumption and environmental i...

We present a quantitative 3D analysis of the motility of the blood parasite Trypanosoma brucei. Digital in-line holographic microscopy has been used to track single cells with high temporal and spatial accuracy to obtain quantitative data on their behavior. Comparing bloodstream form and insect form trypanosomes as well as mutant and wildtype cells under varying external conditions we were able...

Strains of Escherichia coli lacking all cytoplasmic chemotaxis proteins except CheY swim smoothly under most conditions. However, they tumble when exposed to acetate. Acetate coenzyme A synthetase (EC 6.2.1.1) was thought to be essential for this response. New evidence suggests that the tumbling is mediated instead by acetate kinase (EC 2.7.2.1), which might phosphorylate CheY via acetyl phosph...

The effect of methionine starvation on the motility and behavior of normal and nonchemotactic mutants of Salmonella typhimurium was investigated. Methionine starvation eliminates tumbling in the wild type, but fails to do so in an uncoordinated (frequent tumbling) mutant. In the mutant, methionine starvation significantly extends the period of smooth motility that follows a sharp temporal incre...

Chlamydomonas shows both positive and negative phototaxis. It has a single eyespot near its equator, and as the cell rotates during the forward motion, the light signal received by the eyespot varies. We use a simple mechanical model of Chlamydomonas that couples the flagellar beat pattern to the light intensity at the eyespot to demonstrate a mechanism for phototactic steering that is consiste...

We simulate by lattice Boltzmann the nonequilibrium steady states of run-and-tumble particles (inspired by a minimal model of bacteria), interacting by far-field hydrodynamics, subject to confinement. Under gravity, hydrodynamic interactions barely perturb the steady state found without them, but for particles in a harmonic trap such a state is quite changed if the run length is larger than the...

Abstract Run-and-tumble (RnT) motion is an example of active motility where particles move at constant speed and change direction random times. In this work we study RnT with diffusion in a harmonic potential one dimension via path integral approach. We derive Doi-Peliti field theory use it to calculate the entropy production other observables closed form. All our results are exact.