Alexandra Zidovska, Duke

The rich inner life of the cell nucleus: Dynamic organization, active flows and emergent rheology

The nucleus is the control center of the cell, containing genetic material essential for life. Yet, the physical principles underlying its organization in space and time remain a mystery. In this talk, I will show work from my group revealing that the biophysical complexity of the nucleus can be organized around three inter-related and interactive facets: heterogeneity, activity and rheology. Most nuclear constituents are sites of active, ATP-dependent processes and are thus inherently dynamic: The genome undergoes constant rearrangement, the nuclear envelope flickers and fluctuates, nucleoli migrate and coalesce, and many of these events are mediated by nucleoplasmic flows and interactions. And yet there is spatiotemporal organization in terms of hierarchical structure of the genome, its coherently-moving regions and membrane-less compartmentalization via phase-separated nucleoplasmic constituents. Moreover, the non-equilibrium or activity-driven nature of the nucleus gives rise to emergent rheology and material properties that impact all cellular processes via the central dogma of molecular biology. New biophysical insights into the cell nucleus can come from appreciating this rich inner life.
Biophysical Dynamics

January 25, 2022
Zoom | Tuesday, 12:00 pm

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Alexandra Tayar

Assembling Programmable Active Biomaterials

Non-equilibrium thermodynamics is a contemporary research subject that crosses fields from stellar evolution, nonlinear turbulence to biological organisms. Active matter is a subclass of non-equilibrium materials, where symmetry is broken locally, and energy is consumed at the constituent level. The scale of the energy input is elementary in revealing new rich non-equilibrium physics. Currently, there is no unifying thermodynamical framework to describe non-equilibrium systems and energy propagation across scales. Therefore, it is instrumental to develop new programmable active systems that allow for a quantitative parameter space study. Biological building blocks offer reproducibility, uniformity, monodispersity, programmability at the molecular scale, and high energy consumption efficiency. We assembled new men-made DNA-based active systems that exhibit spontaneous flows of materials and self-organization at the mesoscale using these design principles. We study the phase behavior of soft materials in particular liquid phase separation in a non-equilibrium environment. Unexpectedly, we found that the coexistence region of phase separation shifts due to the non-equilibrium nature of the environment in a low-shear regime that existing theoretical frameworks cannot explain. We further study the propagation of active forces across length scales, measuring molecular arrangement and mechanical loads that power active turbulent like dynamic. The unique capabilities of the developed system provide insight into possible mechanisms by which nanometer-sized molecular machines drive macroscale chaotic flows
Physics Colloquium

January 25, 2022
Zoom | Tuesday, 2:00 pm

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Joachim Sauer, Humboldt-Universität zu Berlin, Institut für Chemie

Host(s): Laura Gagliardi via email at lgagliardi@uchicago.edu & Sarah King, 773-834-3809 or via email at sbking@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu.
JFI Hybrid Seminar

January 25, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

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Sri Iyer-Biswas, Purdue


Biophysical Dynamics

February 1, 2022
Zoom | Tuesday, 12:00 pm

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Peter Armitage, Johns Hopkins University

On Ising’s Model of Ferromagnetism

The 1D Ising model is a classical model of great historical significance for both classical and quantum statistical mechanics. Developments in the understanding of the Ising model have fundamentally impacted our knowledge of thermodynamics, critical phenomena, magnetism, conformal quantum field theories, particle physics, and fractionalization in many-body systems. Despite the theoretical impact of the Ising model there have been very few good 1D realizations of it in actual real material systems. However, it has been pointed out recently, that the material CoNb2O6, has a number of features that may make it the most ideal realization we have of the Ising model in one dimension. In this talk I will discuss the surprisingly complex physics resulting in this simple model and review the history of “Ising’s model” from both a scientific and human perspective. In the modern context I will review recent experiments by my group and others on CoNb2O6. In particular I will show how low frequency light in the THz range gives unique insight into the tremendous zoo of phenomena arising in this simple model system. Host: Kathryn Levin via email k-levin@uchicago.edu or by phone at 773-702-7186. Persons who may need assistance please contact Brenda Thomas via email at bthomas@uchicago.edu. or by phone at 773-702-7156.
JFI Hybrid 1st Tuesday Colloquium

February 1, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

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Irmgard Bischofberger, MIT


Computations in Science

February 5, 2022
KPTC 206 | Saturday, 12:15 pm

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Erik How, Department of Biology, University of Mississippi

Host: Seppe Kuehn, via email at seppekuehn@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu.
JFI Hybrid Seminar

February 22, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

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Shankar Mukherji, Washington University in St. Louis


Biophysical Dynamics

March 8, 2022
Zoom | Tuesday, 12:00 pm

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Kenneth Dill, The Department of Chemistry, Stony Brook University

An inference principle for nonequilibrium statistical physics

Host: Andrei Tomakoff, 773-834-7696 or via email at tokmakoff@uchicago.edu and Thomas Witten, 773-702-0497 or by email at t-witten@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu.
JFI Hybrid Seminar

March 8, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

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Rae Anderson, USD


Biophysical Dynamics

March 15, 2022
Zoom | Tuesday, 12:00 pm

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Edouard Hannezo, IST Austria


Biophysical Dynamics

March 22, 2022
Zoom | Tuesday, 12:00 pm

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Mikhail Shapiro, Cal Tech


Biophysical Dynamics

March 24, 2022
Zoom | Thursday, 12:00 pm

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Lisa Jones, Maryland


Biophysical Dynamics

March 29, 2022
Zoom | Tuesday, 12:00 pm

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Changes of State: A Symposium in Honor of Thomas F Rosenbaum


Physics Colloquium

March 31, 2022
KPTC | Thursday, 9:00 am

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Ahmad Khalil, Boston University


Biophysical Dynamics

April 5, 2022
Zoom | Tuesday, 12:00 pm

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Mike Levin, Tufts


Biophysical Dynamics

April 19, 2022
Zoom | Tuesday, 12:00 pm

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Ronald Walsworth, Department of Physics, University of Maryland

Host: Bozhi Tian, 773-702-8749 or btian@uchicago.edu or Peter Maurer 773.834.3931 via email at pmaurer@uchicago.edu Persons who may need assistance please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu.
JFI Hybrid Seminar

April 21, 2022
GCIS W301 and Zoom | Thursday, 4:00 pm

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Tom Kirchhausen, Harvard


Biophysical Dynamics

April 26, 2022
Zoom | Tuesday, 12:00 pm

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Wei Min, Department of Chemistry, Columbia University

Host: Abhirup Guha via email at abhirupg@uchicago.edu. Persons who may need assistance please contact Brenda Thomas at 773-702-7156 or by email at bthomas@uchicago.edu
JFI Hybrid Seminar

April 26, 2022
GCIS W301 and Zoom | Tuesday, 4:00 pm

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Jin Zhang, UCSD


Biophysical Dynamics

May 2, 2022
Zoom | Monday, 12:00 pm

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Katherine Freese, University of Texas at Austin


Physics Colloquium

May 5, 2022
Zoom | Thursday, 3:30 pm

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Eduardo Perozo, UChicago


Biophysical Dynamics

May 17, 2022
Zoom | Tuesday, 12:00 pm

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Suri Vaikuntanathan, Uchicago


Biophysical Dynamics

May 24, 2022
Zoom | Tuesday, 12:00 pm

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