The 2nd Tuesday JFI Colloquium - Hui Zhai, Tsinghua University, Institute for Advanced Study
Closs Lecture - Christopher Chang, University of California, Berkeley
Transition Metal Signaling in the Brain and Beyond
Moh El-Naggar, PhD, Depts of Physics and Astronomy, of Biological Sciences, and of Chemistry, University of Southern California
Far, Fast, & Surprising: Extracellular Electron Transport in Microbial Redox Chains
The stepwise movement of electrons within and between molecules dictates all biological energy conversion strategies, including respiration and photosynthesis. With such a universal role across all domains of life, the fundamentals of ET and its precise impact on bioenergetics have received considerable attention, and the broad mechanisms allowing ET over small length scales in biomolecules are now well appreciated.
In what has become an established pattern, however, our planet’s oldest and most versatile organisms are now challenging our current state of knowledge. With the discovery of bacterial nanowires and multicellular bacterial cables, the length scales of microbial ET observations have jumped by 7 orders of magnitude, from nanometers to centimeters, during the last decade alone! This talk will take stock of where we are and where we are heading as we come to grips with the basic mechanisms and immense implications of microbial long-distance electron transport. We will focus on the biophysical and structural basis of long-distance, fast, extracellular electron transport by metal-reducing bacteria. These remarkable organisms have evolved direct charge transfer mechanisms to solid surfaces outside the cells, allowing them to use abundant minerals as electron acceptors for respiration, instead of oxygen or other soluble oxidants that would normally diffuse inside cells. From an environmental perspective, these microbes are major players in global elemental cycles. From a technological perspective, microbial extracellular electron transport is heavily pursued for interfacing redox reactions to electrodes in multiple renewable energy technologies.
But how can an organism transfer electrons to a surface many cell lengths away? What molecules mediate this transport? And, from a physics standpoint, what are the relevant length, time, and energy scales? We will describe new experimental and computational approaches that revealed how bacteria organize heme networks on outer cell membranes, and along the quasi-one-dimensional filaments known as bacterial nanowires, to facilitate long-range charge transport. Using correlated electron cryo-tomography and in vivo fluorescent microscopy, we are gaining new insight into the localization patterns of multiheme cytochromes along nanowires as well as the morphology and the formation mechanism of these structures. In addition, we will examine the fundamental limits of extracellular electron transport, down to microbial energy acquisition by single cells. These findings are shedding light on one of the earliest forms of respiration on Earth while unraveling surprising biotic-abiotic interactions.
2017 Hillhouse Memorial Lecture - Professor Martin Karplus of Harvard University
Motion: Hallmark of Life. From Marsupials to Molecules
This lecture will present an intellectual path from the role of motion in animals to the molecules that make the motion possible. Motion is usually a way of distinguishing live animals from those that are not, but not always. Just as for the whole animal, motion is an essential part of the function of the cellular components. What about the molecules themsleves? Does motion distinguish molecules designed by people from those developed by evolution? For animals to move, they require energy, which is obtained primarily by using oxygen. So how are whales and dolphins able to use their muscles to dive to great depths, where oxygen is not available? The immediate energy source for muscle function is the molecule ATP. For the generation of this molecule, Nature has developed a marvelous rotary nanomotor. Experiments and simulations, particularly those with supercomputers, are now revealing the mechanism of this nanomotor and other cellular machines.
Closs Lecture-Eric Jacobsen, Harvard University
Frank Wise, Department of Physics, Cornell University
Optoelectronic Properties of Semiconductor Nanocrystal Solids
There is currently great interest in electron transport in nanocrystal solids, driven by potential applications to electronic and optoelectronic devices. A major goal of the field is to achieve bandtype transport of electrons, and despite much progress in this direction, claims of band transport remain controversial. Recently, the fabrication of quasi-two-dimensional superlattices of oriented and epitaxially connected nanocrystals was reported. The structures exhibit both short- and long-range order. Calculations of the electronic states of such “atomically-coherent” assemblies reveal bandwidths that imply promising transport properties. We will report on the synthesis of atomically-coherent superlattices of PbSe nanocrystals, along with structural characterization by x-ray diffraction and high-resolution electron microscopy. Studies of charge transport show that disorder plays a major role in the properties of existing nanocrystal solids. Prospects for achieving true band transport in these structures will be discussed. The talk will begin with a tutorial introduction to semiconductor nanocrystals and devices based on them such as solar cells and light emitters. Host: Philippe Guyot-Sionnest, contact via email at email@example.com or by phone at 2-7461.
Nandini Ananth: Cornell University
Uttam Tambar: UT Southwestern
Stereoselective Functionalization of Unactivated Hydrocarbons
Rainer Weiss, MIT
Meghan Thielges, Indiana University
Conformations and Dynamics of Protein Molecular Recognition
Pedro M Reis, Department of civil Engineering, MIT
Michael Filler, Department of Chemical and Biomolecular Engineering, Georgia Tech
Xiaogang Peng, Zhejiang University
Cheng Chin, University of Chicago
Arvind Murugan - Department of Physics, University of Chicago
Sean Garrett-Roe, University of Pittsburgh
Ultrafast vibrational spectroscopy of ionic liquids: Insight into carbon capture, chemical reactions, and energy storage
Jessie Shelton, University of Illinois(Urbana-Champaign)
Sungyon Lee, Texas A&M University
Particle-induced viscous fingering
Edward Sargent, University of Toronto
Materials and Devices for Flexible Optoelectronics and Renewable Fuels
Vast advances in materials and physical chemistry have led us to the point that, today, we can create a wide range of tunable, solution-processed materials whose spectral properties span the visible and infrared . These are enabling flexible solar cells , top-surface photodetectors, and ubiquitous light sources . I will discuss recent advances that leverage innovations from inorganic synthetic chemists and physical chemists and apply them in the engineering of high-performance optoelectronic devices. I will then discuss a further implication of rapid progress in the cost-effective conversion of solar energy into electrical power. These advances bring about a new challenge, namely, the need for massive (seasonal-scale) storage of energy . I will describe how the use of computational materials science, spectroscopies including ultrafast and synchrotron, and advances in materials chemistry, are accelerating the creation of new catalysts for CO2 reduction and oxygen evolution. I will discuss recent advances including a new high-activity OER catalyst  and a low-overpotential CO2 reduction catalyst based on field-induced reagent concentration . Host: Philippe Guyot-Sionnest; contact via email at firstname.lastname@example.org or by phone at 2-7461. Persons with a disability who may need assistance please contact Brenda Thomas by email at email@example.com or phone at 2-7156.
Bloch Lecture - Dr. Jay Bradner, Dana-Farber Cancer Institute
Inhibition and Degradation of Bromodomain Proteins
Closs Lecture - Sarah Tolbert, UCLA
Solution Processed Nanomaterials: From Basic Science to Solutions to Practical Energy Problems
Shinsei Ryu, University of Chicago
Topological insulators and superconductors--from band theory to interacting systems
Joshua A Frieman, Fermilab, University of Chicago
The Dark Energy Survey
I will overview the Dark Energy Survey (DES) project, highlight its early science results, and discuss its on-going activities and plans. The DES collaboration built the 570-megapixel Dark Energy Camera for the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile to carry out a 5-year, deep, multi-band, optical survey over one eighth of the sky and a time-domain survey that will discover several thousand supernovae. The survey started in Aug. 2013 and is now nearing completion of its fourth observing season. DES was designed to address the questions: why is the expansion of the Universe speeding up? Is cosmic acceleration due to dark energy or does it require a modification of General Relativity? If dark energy, is it the energy density of the vacuum (Einstein's cosmological constant) or something else? DES is addressing these questions by measuring the history of cosmic expansion and the growth of structure through four complementary techniques: galaxy clusters, the large-scale galaxy distribution, gravitational lensing, and supernovae, as well as through cross-correlation with other data sets. I will also discuss how the data are being used to make a variety of other astronomical discoveries, from our Solar System to the most distant quasars.
Steven Boxer, Stanford University
Electric Fields and Enzyme Catalysis
Dr. Daniel Greif, Harvard University
Quantum Antiferromagnets with Single-Site Resolution
Strongly correlated electron systems such as high-temperature superconductors and pseudo-gap states are a cornerstone of modern condensed matter research. A complementary approach to studying solid-state systems is to build an experimentally tunable quantum system governed by the Hubbard model, which is thought to qualitatively describe these systems but is difficult to understand theoretically. Ultracold fermionic quantum gases in optical lattices provide a clean and tunable implementation of the Hubbard model. At the same time, optical microscopy in these systems gives access to single-site observables and correlation functions, and provides dynamic control of the potential landscape at the single-site level. So far, ultracold atom experiments have not been able to reach the low-temperature regime of the Hubbard model, which becomes particularly interesting when doped. Here we report on the observation of antiferromagnetic long-range order in a repulsively interacting Fermi gas of Li-6 atoms on a 2D square lattice containing about 80 sites. The ordered state is directly detected from a peak in the spin structure factor and a diverging correlation length of the spin correlation function. When doping away from half-filling into a numerically intractable regime, we find that long-range order extends to doping concentrations of about 15%. Our results open the path for a controlled study of the low-temperature phase diagram of the Hubbard model.
Dr. Scott W. Schmucker, Zyvex Labs, Richardson, Texas
Atomically-Precise Engineering of Low-Dimensional Systems
As ultra-precise manufacturing technology scales to its atomic limits, we transition into the realm of digital matter and novel composite materials while enabling a burgeoning array of quantum, electronic, and photonic devices. In this talk, we explore several fabrication technologies which enable atomic- precision while elucidating the fundamental science and the engineering applications motivated and enabled thereby. We first compare several related two-dimensional material systems: graphenic materials and hyperdoped delta layers in silicon, each of which can be chemically and lithographically engineered or combined to form van der Waals and covalent delta-doped heterostructures. We explore the influences of interlayer coupling, interfaces, and defects in layered systems. We will then expand our discussion beyond layered systems and extend atomic precision into three dimensions. Discussion will focus on scanned probe lithography for the fabrication of donor atom quantum devices in silicon and recent efforts to expand these devices to include acceptor dopants and to enable three-dimensional architectures. We discuss the physics and fabrication of donor atom qubits in silicon, and through a combination of scanning tunneling microscope-driven lithography and Zyvex engineering, we demonstrate the scaling of manufacturing precision to the atomic scale
Daniel Diermeier, University of Chicago
The talk will discuss models of elections from game-theory to statistical mechanics. I will discuss their relative strengths and weaknesses and their ability or inability to explain voting behavior in mass elections.