Simon G. J. Mochrie

Key takeaways

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Reference excerpt

Simon G. J. Mochrie is a professor of Physics and Applied Physics at Yale University. His research focuses on experimental biophysics, soft condensed matter physics, and quantitative microscopy. He is known for x-ray photon correlation spectroscopy (XPCS), a technique he first demonstrated in 1991 that is now used at synchrotron facilities worldwide.

Education and career Mochrie received a BA from the University of Oxford and a PhD in Physics from the Massachusetts Institute of Technology (MIT) in 1985, where he studied phase transitions in systems exhibiting low-dimensional behavior. He subsequently worked as a Member of Technical Staff at AT&T Bell Laboratories and then served on the faculty at MIT before joining Yale University in 2000 as Professor of Physics and Applied Physics. In 2008, Mochrie co-founded Yale's Integrated Graduate Program in Physical and Engineering Biology (PEB) together with Lynne Regan, Corey O'Hern, and Thomas D. Pollard. The program trains graduate students to apply physical and engineering approaches to biological systems across traditional disciplinary boundaries.

Research

X-ray photon correlation spectroscopy Mochrie developed x-ray photon correlation spectroscopy (XPCS), a technique that uses the coherent scattering of synchrotron X-rays to characterize the slow dynamics of polymeric and colloidal systems on shorter length scales than achievable with optical methods. The method was first demonstrated by Mochrie and Mark Sutton in 1991 and has since motivated the implementation of dedicated XPCS beamlines at synchrotron facilities around the world. This work was recognized with the 2009 Arthur H. Compton Award from the Advanced Photon Source, shared with Gerhard Grübel and Mark Sutton.

Condensed matter and soft matter physics Earlier in his career, Mochrie carried out experimental studies of the properties, phase behavior, and phase transitions of soft matter, surfaces, and biomaterials using high-resolution X-ray scattering techniques.

Biological physics Mochrie's more recent research focuses on the physics of living materials. His laboratory uses theoretical and computational approaches together with experimental methods including optical tweezers, fast-scanning random-access STED microscopy, and quantitative microscopy to study chromatin organization and dynamics. Current projects include single-molecule optical tweezer measurements on nucleosomes, protein degradation in yeast, and the role of peripheral chromatin in nuclear mechanics. A contribution of his group is the conserved-current loop extrusion (CCLE) model, which interprets loop-extruding cohesin as a conserved current to self-consistently predict chromatin spatial organization from cohesin distributions alone, applicable across both vertebrate and non-vertebrate organisms. In other work, Mochrie used small-angle X-ray scattering on single insect scales to identify ordered photonic nanostructures grown through the self-organizing propensity of cellular lipid bilayer membranes. He also demonstrated that the folding and unfolding thermodynamics of repeat proteins can be quantitatively described by the classical one-dimensional Ising model.

Awards and honors Arthur H. Compton Award (2009) – Awarded by the Advanced Photon Source, shared with Gerhard Grübel (DESY) and Mark Sutton (McGill University), for pioneering efforts in x-ray photon correlation spectroscopy. Allen Distinguished Investigator (2020) – Awarded by The Paul G. Allen Frontiers Group, a division of the Allen Institute. Co-led (with Megan C. King) a project on the physical and molecular forces maintaining nuclear size, funded at $1.5 million over three years. Dylan Hixon '88 Prize for Teaching Excellence in the Natural Sciences (2021) – One of the highest teaching honors bestowed by Yale College, recognizing a "towering figure" in undergraduate education.

Selected publications Mochrie, S.G.J.; Mayes, A.M.; Sandy, A.R.; Sutton, M.; Brauer, S.; Stephenson, G.B.; Abernathy, D.L.; Grübel, G. (1997). "Dynamics of Block Copolymer Micelles Revealed by X-Ray Intensity Fluctuation Spectroscopy". Physical Review Letters. 78 (7): 1275–1278. Bibcode:1997PhRvL..78.1275M. doi:10.1103/PhysRevLett.78.1275. Bailey, Mary Lou P.; Surovtsev, Ivan; Williams, Jessica F.; Yan, Hao; Yuan, Tianyu; Li, Kevin; Duseau, Katherine; Mochrie, Simon G.J.; King, Megan C. (2023). "Loops and the activity of loop extrusion factors constrain chromatin dynamics". Molecular Biology of the Cell. 34 (7): ar78. doi:10.1091/mbc.E23-04-0119. PMC 10398873. PMID 37133434. Yuan, Tianyu; Yan, Hao; Li, Kevin C.; Surovtsev, Ivan; King, Megan C.; Mochrie, Simon G.J. (2024). "Cohesin distribution alone predicts chromatin organization in yeast via conserved-current loop extrusion". Genome Biology. 25: 293. doi:10.1186/s13059-024-03432-w. Yuan, Tianyu; Yan, Hao; Bailey, Mary Lou P.; Williams, Jessica F.; Surovtsev, Ivan; King, Megan C.; Mochrie, Simon G.J. (2024). "Effect of loops on the mean-square displacement of Rouse-model chromatin". Physical Review E. 109 (4) 044502. doi:10.1103/PhysRevE.109.044502. PMID 38755928.

References

External links Mochrie Lab at Yale University Yale Department of Physics faculty page Simon G. J. Mochrie publications indexed by Google Scholar

Worked examples

Example 1 — a first encounter with Simon G. J. Mochrie

Start with the simplest possible case. Write down what Simon G. J. Mochrie claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Simon G. J. Mochrie before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Simon G. J. Mochrie ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Simon G. J. Mochrie

In research: Simon G. J. Mochrie appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Simon G. J. Mochrie in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Simon G. J. Mochrie is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alumni of the University of Oxford, American physicists, Biophysicists, so understanding it makes those chapters shorter.
In everyday life: Look for Simon G. J. Mochrie outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Simon G. J. Mochrie in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Simon G. J. Mochrie means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
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Frequently asked questions

What is Simon G. J. Mochrie in simple terms?

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Why does Simon G. J. Mochrie matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Simon G. J. Mochrie?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

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It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Simon G. J. Mochrie.