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Condensed Matter Physics

Biophysics

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Full-Text Articles in Statistical, Nonlinear, and Soft Matter Physics

Long-Range And Chaotic Active Mixing Of Swimming Microbes In A Vortex Chain Flow, Nghia Le Jan 2023

Long-Range And Chaotic Active Mixing Of Swimming Microbes In A Vortex Chain Flow, Nghia Le

Honors Theses

We present experiments studying the motion and active mixing of swimming mi- crobes in laminar, vortex-dominated fluid flows. We are testing a theory that predicts the existence of swimming invariant manifolds (SwIMs) - invisible, one-way barriers blocking the paths of self-propelled tracers in the flow in one direction. We also pro- pose that the SwIMs together can form chute structures in three-dimensional phase space that facilitate cross-vortex transport of the microbes. We also observe evidence of how these structures promote long-range transport at different non-dimensional velocities (microbe’s velocity relative to flow velocity). Long-range transport is quan- tified by measuring the …


X-Ray Characterization Of Mesophases And Phase Transitions Of Dna Analogues In Solutions, Mustafa Selcuk Yasar Nov 2016

X-Ray Characterization Of Mesophases And Phase Transitions Of Dna Analogues In Solutions, Mustafa Selcuk Yasar

Doctoral Dissertations

We think of DNA as double-stranded helices (duplex), but the polymer exists in many conformations. Several triplex and quadruplex DNA structures can be formed in laboratory settings and exist in nature. This thesis first provides a brief description of the nature of the order in arrays of duplex DNA under biologically relevant molecular crowding conditions. Then we compare the duplex DNA mesophases with the corresponding liquid crystalline phase behavior of the triplex and quadruplex DNA analogues. In particular, we focus on G-quadruplexes. Observed in the folds of guanine-rich oligonucleotides, G-quadruplex structures are based on G-quartets formed by hydrogen bonding and …