Rigid or flexible particles suspended in viscoelastic fluids are ubiquitous in the food industry (e.g. pastes), industrial molding applications (all composites and 3-D printed parts), the energy industry (e.g. fracking fluids), and biological fluids (i.e. swimming of bacteria in mucous). The mathematical description of these suspensions is in its infancy. For example, the foundational work in Newtonian suspensions was accomplished by Einstein in 1905, but that same calculation in an elastic fluid appeared in 2018 (!) However, the real breakthrough has been the development of a computational simulation of such viscoelastic suspensions, with particle level resolution. These simulations will allow the principles which govern the simplest flows of such suspensions, which are now only beginning to be understood, to become elucidated in the next decade. I will describe a series of foundational problems that have now been analyzed using these new computational methods including a comparison to existing experiments. I will then discuss those problems that represent “the next steps” in the field.

While populations of single-celled organisms increase exponentially, animal cell growth must be coupled to organism growth for tissues to maintain their structure. These spatial constraints lead to a different regime of growth and division regulation known as contact inhibition of proliferation. We still lack a general framework to describe contact inhibition across different biological systems. Here we use model epithelial monolayers with varying spatial constraints to explore how contact inhibition affects cell growth and division. We introduce a concept of tissue confinement which describes the extent to which spatial constraints suppress cell growth in different tissues. Interestingly, confinement has no effect on cell division leading to a decoupling between rates of cell growth and division. In confined tissues cell division outpaces growth causing cell size to decrease. However, when cell size decreases below a specific value cell division becomes arrested. This final cell size is near a physical limit set by the amount of space occupied by DNA in the cell. By perturbing cell division regulation, it is possible to push cells closer to this limit, however, this leads to DNA damage suggesting loss of size regulation could play a role in the development of cancer.

Feet look quite different from fins but face the same structural demand to be sufficiently stiff in order to withstand the forces of propulsion. In this talk, I will show that curvature-induced stiffness is the common principle underlying the stiffness of both primate feet and rayed fish fins. The principle is evident in a drooping currency note or slice of pizza that significantly stiffens upon slightly curling it along the width. We use mathematical analysis, physical mimics, and biological experiments to derive the relationship between curvature and stiffness, and apply this understanding to track the evolution of foot curvature among hominins (human lineage). I will also show how the same principle manifests in fish fins despite their different morphology, with implications for the 380 million year old water-to-land evolutionary transition among vertebrates.

Advances in technology have begun to allow for the production of large groups, or swarms, of robots; however, there exists a large gap between their current capabilities and those of swarms found in nature or envisioned for future robot swarms. These deficiencies are the result of two factors, difficulties in algorithmic control of these swarms, and limitations in hardware capabilities of the individuals. Creating a hardware system for large robotic swarms is an open challenge; cost and manufacturability pressure hardware designs to be simple with minimal capabilities, while algorithm design favors more capable hardware. The robot design must balance these factors to create a simple robot that is, at the same time, capable of performing the desired behaviors. In this talk, I will discuss the many challenges associated with creating a robot swarm at this scale and the implications this has for creating even larger, more capable swarms in the future.

The story of Earth is a 4.5-billion-year saga of dramatic transformations, driven by physical, chemical, and—based on a fascinating growing body of evidence—biological processes. The co-evolution of life and rocks unfolds in an irreversible sequence of evolutionary stages. Each stage re-sculpted our planet’s surface, while introducing new planetary processes and phenomena. This grand and intertwined tale of Earth’s living and non-living spheres is coming into ever-sharper focus thanks to the emerging field of mineral informatics, which employs powerful analytical and visualization methods applied to large and growing mineral data resources. The histories of terrestrial planets and moons are best preserved in the information-rich record of minerals. Mineral attributes, including trace and minor elements, isotopes, solid and fluid inclusions, structural defects, exsolution and twinning, geologic and petrologic context, and scores of other properties, reveal the ancient origins and complex evolution of Earth’s crust. Thus, mineral informatics is ushering in a new era of discovery, while holding the promise to transform mineralogy into a predictive science.

After a century of biochemical and genetic onslaught on the embryo we are left with an inexhaustive parts list with an increasingly baroque logic. How do we begin to assemble complex living systems from knowledge of their parts list? In this talk, I will attempt to pursue a statistical (physics) approach to discerning the design principles that might be in play in developing organisms. The model system of focus will be the fruit fly's wing, within which we (in collaboration with the Carthew Lab @ NU) pursue a field-theoretic approach to studying the "response function" of the system in response to small, or linear, changes in the genome and environment that the system has evolved to cope with. The central result is an empirical delineation of the manifest degeneracies in the genotype to phenotype map, and an attempt to understand how living matter balances the apparent conflict between the requirements of a robust engineering protocol that permits its self-assembly and the ability to evolve. The hope is that this attempt of ours opens up more questions, rather than give conclusive answers on any matter, yet.