Results 141 to 150 of about 901 (179)

Bioconvective patterns, synchrony, and survival

Physical Review Letters, 1990
With and without bioconvective pattern formation, a theoretical model predicts growth in light-limited cultures of motile algae. At the critical density for pattern formation, the resulting doubly exponential population curves show an inflection. Such growth corresponds quantitatively to experiments in mechanically unstirred cultures.
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Falling plumes in bacterial bioconvection

Journal of Fluid Mechanics, 2001
Experiments by Kessler on bioconvection in laboratory suspensions of bacteria (Bacillus subtilis), contained in a deep chamber, reveal the development of a thin upper boundary layer of cell-rich fluid which becomes unstable, leading to the formation of falling plumes.
Metcalfe, Aisling M., Pedley, T. J.
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Gyrotactic bioconvection in three dimensions

Physics of Fluids, 2007
The bioconvection equations, based on the continuum model of Pedley et al. [J. Fluid Mech. 195, 223 (1988)], consist of the Navier-Stokes equations for an incompressible fluid coupled with a micro-organism conservation equation. These equations are solved efficiently using a semi-implicit second-order accurate conservative finite-difference method. The
Ghorai, S., Hill, N. A.
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Evolution of bioconvective patterns in variable gravity

Physical Review A, 1991
Measurements are reported of the evolution of bioconvective patterns in shallow, dense cultures of microorganisms subjected to varying gravity. Various statistical properties of this random, quasi-two-dimensional structure have been found: Aboav's law is obeyed, the average vertex angles follow predictions for regular polygons, and the area of a ...
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Bioconvection induced by bacterial chemotaxis in a capillary assay

Biochemical and Biophysical Research Communications, 2017
Bacterial chemotaxis allows cells to swim toward a more favorable environment. Capillary assays are a major method for exploring bacterial responses to attractive and repellent chemicals, but the accumulation process obtained using a capillary containing chemicals has not been investigated fully.
Takahiro Abe, Shuichi Nakamura, Seishi Kudo   +2 more
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A Data-Driven Approach on Bioconvection Flow

In this study, machine learning modeling is utilized on a bioconvection flow problem. The two dimensional, time independent natural convection flow problem in the presence of oxytactic bacteria is considered inside a unit square cavity. The dimensionless governing equations in terms of stream function, temperature, oxygen concentration, bacteria ...
Bengisen Pekmen, Merve Gurbuz-Caldag
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Bioconvection in suspensions of oxytactic bacteria: linear theory

Journal of Fluid Mechanics, 1996
When a suspension of the bacteriumBacillus subtilisis placed in a chamber with its upper surface open to the atmosphere, complex bioconvection patterns form. These arise because the cells (a) are denser than water, and (b) swim upwards on average so that the density of an initially uniform suspension becomes greater at the top than at the bottom.
Hillesdon, A. J., Pedley, T. J.
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Bioconvection and front formation ofParamecium tetraurelia

Physical Review E, 2007
We have investigated the bioconvection of Paramecium tetraurelia in high-density suspensions made by centrifugal concentration. When a suspension is kept at rest in a Hele-Shaw cell, a crowded front of paramecia is formed in the vicinity of the bottom and it propagates gradually toward the water-air interface.
So, Kitsunezaki, Rie, Komori, Terue, Harumoto   +2 more
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Fractal Dimension of Bioconvection Patterns

Journal of the Physical Society of Japan, 1990
Shallow cultures of the motile algal strain, Euglena gracilis, were concentrated to 2 x 10 to the 6th organisms per ml and placed in constant temperature water baths at 24 and 38 C. Bioconvective patterns formed an open two-dimensional structure with random branches, similar to clusters encountered in the diffusion-limited aggregation (DLA) model. When
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Microimaging of Algal Bioconvection by Scanning Electrochemical Microscopy

Analytical Chemistry, 2007
Local bioconvection generated by algal flagellar movement was imaged by scanning electrochemical microscopy. As a microelectrode probe vertically approached an individual multicellular flagellate alga, Volvox carteri, an oxidation current of a coexisting redox marker ([Fe(CN)6]4-) increased gradually, due to bioconvective enhancement of mass transport,
Isao, Shitanda, Yutaka, Yoshida, Tetsu, Tatsuma   +2 more
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