Calendar of MRSEC Events

Abstract: Human influenza viruses, as well as SARS-CoV-2, undergo fast evolution driven by immune pressure of their hosts. Viral strains and our immune systems are a tightly coupled, fast-evolving ecosystem. Fitness models have become an important tool to predict these dynamics and to guide the selection of vaccine strains. In this talk, I present the cross-scale concepts of current predictions: changing molecular interactions of viral proteins and human antibodies affect immune protection, generate time-dependent fitness differences between strains, and shape the global evolution of the pathogen. This analysis contains building blocks of a new, computable framework for human adaptive immunity.

More about the Squishy Physics Seminar

Abstract: Identifying effective immunization schemes against highly mutable pathogens such as HIV and influenza viruses remains a persistent public health challenge. Our work addresses this challenge by analyzing a simplified model of affinity maturation, the Darwinian evolutionary process that B cells undergo during immunization.

In this presentation, I will introduce a minimal framework that identifies optimal selection forces exerted by time-dependent vaccination protocols. This framework aims to maximize the production of broadly neutralizing antibodies (bnAbs) that can protect against a broad spectrum of pathogen strains. The model utilizes a path integral representation within a mean-field limit to provide guiding principles for optimizing vaccine-induced selection forces. Additionally, I will discuss our ongoing research that extends this theoretical framework to more complex immunological scenarios. This extension employs regression algorithms to derive simplified dynamical equations from time series data generated by agent-based and population simulations. These equations effectively capture the evolution of B cell populations and antibody responses, providing valuable insights into antigen competition and other nonlinear effects that emerge from the complex feedback mechanisms of immunological memory.

More about the Soft Condensed Matter Seminar

Abstract: Nature has developed diverse adhesion strategies, from mussel-inspired underwater glues to gecko-like dry adhesion. Silk fibroin, with its tunable structure and exceptional mechanical properties, provides a versatile foundation for bioinspired adhesives. This seminar examines key natural adhesion mechanisms and how silk fibroin can be engineered into various material formats to create functional adhesives. By leveraging its unique properties, silk-based adhesives can be tailored for applications ranging from underwater adhesion to biodegradable labeling and even superhero inspired adhesives.

More about the Squishy Physics Seminar

Abstract: The towering successes of twentieth century theoretical physics were marked by two guiding principles: symmetry and energy functionals (reflecting equilibrium dynamics). Yet how we can exploit these principles to develop a theory of living systems is unclear since the biological world is composed of heterogeneous, interacting components operating out of equilibrium. In this talk, I will argue that one possible strategy for taming biological complexity is to embrace the idea that many biological behaviors we observe are “typical” and can be modeled using random systems that respect biologically-inspired constraints. I will focus on high-dimensional ecology and show how we can use tools from statistical physics (cavity method, DMFT) to understand the emergence of chaos in the ecosystems with non-reciprocal interactions.

More about the Soft Condensed Matter Seminar

Abstract: In this talk, we study a minimal model of a system with coexisting nematic and polar orientational orders, where one field tends to order and the other prefers isotropy. For strong coupling, the ordered field aligns the isotropic one, locking their orientations. The phase diagram reveals three distinct phases—nematopolar (aligned orders), nematic (independent orders), and isotropic (vanishing orders)—separated by continuous and discontinuous transitions, including a triple and a tricritical point. We find unique critical scaling for the nematopolar-nematic transition, distinct from standard nematic or polar universality classes. Additionally, in the locked nematopolar phase, we show nematic +1/2 topological defect pairs are connected and confined by strings with constant tension. These strings arise from frustration in locking the orientational orders and can be interpreted as elongated cores of +1 polar topological defects. When a sufficiently strong background field couples to the polar order, all topological defects are expelled from the region. Analytical predictions are quantitatively confirmed by numerical simulations. Based on joint work with Amin Doostmohammadi.

More about the Soft Condensed Matter Seminar