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Biological Physics (CPLC) Seminar: Seungeun Oh

2/6/2020 12:30:49 PM

Seungeun Oh 

Harvard Medical School

Cell Size Regulation in Differentiation and Disease by Quantatative Chemical Imaging

Cell growth is the basis for myriad biological processes ranging from development, regeneration and tumor growth. Yet how cell is maintained at the right size is still poorly understood. Accurate measurement of cell size is critical for providing answers to these open questions. I will describe the application and development of optical microscopy techniques including quantitative phase imaging and stimulated Raman scattering microscopy for investigation of the cell size regulation in skeletal development. Specifically, I will present Normalized Raman Imaging (NoRI) that measures the absolute concentrations of total protein, total lipid, and water at a high spatial resolution in tissue. NoRI achieves the absolute quantification by combining Stimulated Raman scattering (SRS) microscopy with a novel computational algorithm that removes the effect of light scattering in thick tissue samples. NoRI is a label-free technique that can measure live or fixed tissue sections, cultured cells and small model organisms without any use of staining. NoRI reveals that cell types and tissue types have characteristic protein and lipid density, which may change with developmental or disease processes.



2/6/2014 12:00:00 PM Siv Schwink

Peter Adshead is a theoretical astrophysicist and cosmologist with a strong background in high-energy theory. In the most general terms, his research goal is to explain the physics behind why the universe looks the way it does. His research program leverages big-data observational evidence from large-scale experiments that are probing the initial conditions of the universe.

“This is an exciting time in theoretical cosmology,” remarks Adshead. “Ongoing and planned experimental observations—looking at both the temperature and polarization of the cosmic microwave background (CMB) and at complementary datasets, such as galaxy surveys—provide huge amounts of data about the statistical distribution of matter throughout the universe, enabling increasingly precise cosmological predictions. Theorists are called on to venture well beyond the simplest approximations.”

Adshead is particularly interested in persistent problems related to the inflationary epoch that lasted until just 10-36 seconds after the Big Bang.

 “The theory of inflation, in a nutshell, is a postulated period in the earliest history of our universe wherein the expansion of the universe was accelerating. While such an epoch neatly solves some of the fine-tuning issues associated with hot big-bang cosmology, the problem is that no known type of matter—whether radiation or dust—will mathematically cause the expansion of the universe to accelerate. We simply do not know what causes the primordial acceleration.

“One of the nicest aspects of inflation is that the quantum fluctuations of spacetime during this period are what we believe provide the seeds for the formation of large-scale objects, including galaxies,” explains Adshead. “Looking at the statistics of large-scale structures—considering that the galaxies are the evolved quantum fluctuations—we can directly probe the physics of what’s happening at the earliest times.”

“The microwave background experiments that measure primordial B-modes—considered the smoking gun signal of inflation—are now approaching a sensitivity level where we might be able to say something definitive about the dynamics and energy scale of inflation, which in turn will shed new light on the fundamental theory of nature,” he adds.

At Illinois, Adshead looks forward to teaching and to developing new courses. He favors a highly interactive teaching methodology that combines instruction with mentorship to foster intellectual curiosity, the free exchange of innovative ideas, and the development of strong speaking and questioning skills through regular open debates.

“My goal as an educator is not only to provide a platform for the enterprising undergraduate to learn interesting science, but also to instill in them a sense of the research process,” explains Adshead. “I believe that undergraduates can be effective in doing a properly packaged project, with clear boundaries set such that they are not overwhelmed by the need to learn a discouraging amount of prior knowledge.”

With graduate students, Adshead will emphasize the importance of effective collaboration: “I am interested in developing advanced specialty courses in cosmology, concentrating on modern aspects such as the microwave background and inflation, and emphasizing collaborative group work. Such courses are essential for bringing graduate students up to speed with the current state of the field.”

Adshead received his bachelor’s degree in mathematical physics from the University of Canterbury, New Zealand, in 2004, graduating with first-class honors. He received his master of science (2007), master of philosophy (2008) and doctoral degrees (2010) from Yale University.

At Canterbury, he was selected for a Fulbright Scholarship (2005), which he declined. At Yale, Adshead received the Dirk Brouwer Prize (2011), and the Leigh Page Prize (2005). Prior to joining the faculty at Illinois, Adshead worked as a postdoctoral fellow at the Kavli Institute for Cosmological Physics at The University of Chicago (beginning in 2010) and at the University of Cambridge (beginning in 2013).