Check out our new paper on the mechanics of hierarchical structures – and its relevance for evolution – published today in PNAS.

Also, a great write-up is available here.

In our previous paper on the evolution of multicellularity, we showed that mechanical stresses develop during growth, eventually fracture clusters of cells into two pieces. Now we ask: when faced with this mechanical challenge, what is the best way to evolve large size? In our new paper, selected as a Rapid Communication in PRE, we show increasing bond strength does little, but modify how cells pack does a lot!

Our new paper in PRL investigates an effective fluctuation response relationship in biofilms featuring death and reproduction. The fluctuation-dissipation theorem, derived by Harry Nyquist in the 1920’s, is essential to our understanding of equilibrium solids. The relationship between thermal fluctuations and mechanical responses provided a framework through which mechanical properties of solids were measurable and predictable. Our paper. The same may be possible for living films; we investigated it in collaboration with the Hammer lab, here  at Georgia Tech’s School of Biological Sciences. Our work builds on a beautiful paper from Risler, Peilloux, and Proust, which investigated a model of apoptosis and reproduction in tissues.

What do nascent multicellular organisms and colloidal particles have in common? Packing matters! Check out our new Nature Physics paper to learn more! Also, be sure to read the fantastic News&Views article on this work by Vernita Gordon!

Our new preprint investigates how coffee-ring-effect produces gradients in cell-density when a drop of liquid culture is dried. These initial conditions have a large impact on the subsequent competition between strains, and can even switch which strain wins. Thus, the coffee-ring effect may ultimately impact evolutionary outcomes.

Dhaivat Mehta was one of the grand award winners at this year’s Georgia Science & Engineering Fair! He has been working with us on his project “Modeling T6ss-Mediated Killing in Microbial Colonies.”

Check out our paper on a different form of active matter, whose activity is not due to mobility, but to death and reproduction! Published this week in Nature Communications, this interdisciplinary paper brought together classic physics, microbiology, ecology and more!

Doominic Robe and Stefan Boettcher, of Emory, and Paolo Sibani, of University of Southern Denmark, and I recently searched for – and found – signatures of ‘record dynamics’ in aging colloidal glasses. The paper was recently published in EPL (arxiv version here).

Cornelia Rosu, then of Paul Russo’s lab in the Georgia Tech Department of Materials Science and Engineering, led an investigation of domed microcylinders in cholesteric liquid crystals.

How can a two component system phase separate if its constituents are densely packed and lack mobility? See the preprint from our collaboration with Will Ratcliff, Brian Hammer, and Sam Brown here to find out!