Tristan Ursell's Research and Recreation Page
[ Contact Info | CV | Biophysics Research | Teaching | Recreation | Previous Research | Education | E-mail Me Now ]
"Some laws are unwritten, but they are better
established than all written ones."
-Seneca Rhetor
"All models are wrong, some are useful."
- George Box
Contact Info
Tristan Ursell, PhD
1200 E California Blvd
MC 128-95
Pasadena, CA 91125
Office/Lab: Broad Center 71
tel: (626) 395 8889
fax: (626) 395 5867
natsirts@caltech.edu
(email - take off the last 's')
Outdated personal homepage that has some good links and pictures.
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Research Interests
- Membrane-Protein Interactions, Mechanosensation, and Membrane-Mediated Protein-Protein Interactions
Schematic of Bacterial Hypo-osmotic Shock (PDF)
Cooperative Gating and Spatial Organization of Membrane Proteins through Elastic Interactions
Tristan Ursell, Kerwyn Casey Huang, Eric Peterson and Rob Phillips (2007) PLoS Computational Biology 3(5) e81.
(PDF)
You need the latest version of Adobe Flash Player to view the following videos.
Adobe recommends uninstalling then reinstalling the newest version.
Capillary Action - now a major motion picture. It's a little cheesy, but fun.
Emerging Roles for Lipids in Shaping Membrane-Protein Function
Rob Phillips, Tristan Ursell, Paul Wiggins and Pierre Sens (2009) Nature 459:379-385.
(PDF)
The Role of Lipid Bilayer Mechanics in Mechanosensation
Tristan Ursell, Jane' Kondev, Dan Reeves, Paul A. Wiggins and Rob Phillips
Published in the book "Mechanosensitivity in Cells and Tissues" - Springer-Verlag (2008) Editor: Andre Kamkin
(PDF)
Statistical Properties of Interacting Membrane Proteins
Poster for the Pan-American Advanced Studies Institute (PASI), Bariloche, Argentina 2006
(PDF)
Membrane Mechanics as a Probe of Ion-channel Gating Mechanisms
Dan Reeves, Tristan Ursell, Pierre Sens, Jane' Kondev and Rob Phillips (2008) Phys Rev E, 78: 041901.
(PDF)
- Ternary Phase Separation and Resulting Membrane Morphology
Lipid membranes are envisioned as a heterogeneous mix of lipids, proteins and small molecules. Special groupings of saturated lipids and cholesterol known as `lipid rafts' are thought to serve as platforms for signaling, trafficking and material transport across the plasma membrane. Model membranes have demonstrated the existence liquid-ordered and liquid-disordered lipid domains, similar to lipid rafts. However, questions remain as to how the cell might maintain this heterogeneity over time when coalescence forces overwhelmingly drive the system to complete phase separation. Membrane morphology may be a key player in maintaining this heterogeneity and the organization of such domains in the membrane.
All scale bars are 10 um.
Dynamic Morphologies and Coalescence of Lipid Domains
Tristan Ursell and Rob Phillips
Poster for the Keystone Symposium, Big Sky, MT 2008 and BPS 2008 (PDF)
Accompanying Talk (PPT)
Morphology and Interaction between Lipid Domains
Tristan Ursell, Bill Klug and Rob Phillips (2009) Accepted to PNAS.
(Preprint)
Lipid Domain Order and the Algebra of Morphology
Tristan Ursell and Rob Phillips (2009) Submitted to Biophysical Journal.
(Request Preprint)
Download a cool background picture of a phase separated vesicle.
Download images of phase separated vesicles (fully separated, oriented multi-domains, scale bar - 10um).
A video showing spinodal decomposition and phase separation of a multi-component GUV:
3D deconvolution microscopy image of bulging domains on the surface of a phase separated GUV:
Lipid domains that 'viscous fingered' before solidification (aka - the Faberge Vesicle):
Please e-mail me if you'd like higher quality versions of these videos.
- Response of the Hog1 MAPK Pathway in S. cerevisae Shows an Ability to Learn from Previous Stimulation
In conjunction with the Van Oudenaarden Lab @ MIT
ASCB 2006 Poster (PDF)
- Phase Separation and Morphology of Membranes in (nearly) Living Cells
Pluggin away.
- Mechanosensors, lipids and bacterial shape through the cell cycle (in E. coli)
Collaborators:
If by some strange chance you've seen one of my talks ... and liked it, you can e-mail me for a copy.
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Teaching Experience
- Screening of Planet Earth: Seasonal Forests at Caltech's Beckman Auditorium - Led a pre- and post-screening discussion, tried to get people excited about trees , and gave away some trees to kids. Featured in many LA event calendars. Video coming soon.
- In Your Eye's Mind - Talk given for the LA intellectual salon MindShare in August 2008. Read a review!
- Marine Biological Laboratory - Physiology Course - Summer 2007
- Physical Biology
2008, 2007, 2006 and 2005. You have to experience it to believe it.
Some recent fun videos and pictures created during the bootcamp:
Amoebas crawl around, high-five each other, and one eats a small Chilomonas. Totally awesome to see live.
Cool backgrounds I made from the Cytoplasmic Streaming video found below.
Treadmilling macrophage in DIC, showing vesicular transport and filopodia extensions.
A 3D deconvolution microscopy image of the naturally flourescent cells found on the surface of a violet petal (scale bar 100um).
Cytoplasmic Streaming in a Water Lily (Nymphaeaceae) petal cell.
Note the rapid movement of transport vesicles to and from the nucleus and through the plasmodesmata, mediated by molecular motors on microtubules.
- APh 162 - Biological Physics Laboratory
2005 and 2006
- ME 96 - Advanced Mechanical Engineering Laboratory
2005
- Protocols and Tutorials:
Protocol for electroformation of giant unilamellar vesicles.
Diagram demonstrating how to make a micro-pipette for giant unilamellar vesicle aspiration (see Rawicz et al, Biophys J 2000).
Basic Cloning Tutorial - Bootcamp-flavored explanation of cloning, PCR, ligation, restriction digest, and more.
Bootcamp Protocols - composite of recipes, specific instructions for various molecular biology and organism perp procedures, basic microscopy, and more.
Tutorial on derivation and solutions of the diffusion equation (with derivation of mean first passage time - coming soon). Someone actually found this useful!
Tutorial on the Cahn-Hilliard equation and spinodal decomposition kinetics.
Tutorial on simulating Worm-like Chain in a thermal environment (coming soon).
Tutorial on differential geometry of curves and surfaces, with applications to energetics. (coming soon)
Matlab Image Analysis Tutorial (m-file) - A well-commented m-file to teach basic image processing concepts.
LaTex cheat sheets (not written by me) PDF1 PDF2
Physical constants 'business card' reference sheet (PDF)
Recreation
- Backpacking- see Travel
- Rockclimbing - 5.10, get your ass in the gym Tristan!
- Travel - Some Recent Excursions
2001 : Baja California, Yucatan Peninsula
2002 : Valencia - Spain (for 4 months); Mallorca, England, Switzerland, Italy, France (~3 weeks); Colorado, Southwestern Utah, Wyoming, Idaho, Oregon (~3 weeks)
2003 : England, Scotland, The Netherlands, France, Switzerland, Italy, Spain - all together ~8 weeks
2004 : Sierra Nevadas, Arizona, New Mexico
2006 : Costa Rica - Corcovado National Park and San Jose (~2 weeks); Patagonia, Argentina (~3 weeks)
2007 : Tierra del Fuego - Argentina and Torres del Paine - Chile (~2.5 weeks)
2008 : Spain and Egypt (~2.5 weeks); Epic trip to Eureka Dunes, CA (~3 days); Epic trip to Lost Coast, CA (~3 days)
- National Parks
Ones I like:
Zion NP, Death Valley NP, Yellowstone NP, Yosemite NP, Arches NP, Canyonlands NP, Grand Canyon NP, Joshua Tree NP, Bryce Canyon NP, Kings Canyon and Sequoia NPs, Channel Islands NP, Crater Lake NP, Muir Woods NM, Grand Tetons NP, Badlands NP, White Sands NM, Carlsbad Caverns NP, Petrified Forest NP
Ones I still need to visit:
Denali NP, Mt. Rainier NP, Olympic NP, Rocky Mountain NP, Big Bend NP, Black Canyon of the Gunnison NP
- Photograph - mostly outdoor - in black and white and color.
- Music of all kinds. As of late, what I will generically call 'electronic' music has been my listening (e.g.) and composition interest.
- Driving
- Urban Exploration
- Pottery - Bee Mix, Rod's Bod, some Porcelain
- Building weird stuff - Jacob's ladder, Cloud Chamber, Sterling Engine etc..
- North Jersey - Fact: There are over 600 Diners in NJ - the highest density in the world!
- Pondering the meaning and philosophy of life and religion.
- The story of my life.
- My thoughts about humanity.
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Previous Research - Solid State Physics
-
Theory and design of high efficiency thermoelectric materials.
Adviser G. Jeff Snyder while working at Jet Propulsion Laboratory.
Snyder G.J. and Ursell T.S. (2003) Thermoelectric Efficiency and Compatibility, Phys. Rev. Lett. 91, 14
(PDF)
Ursell T.S. and Snyder G.J. (2002) Compatibility of Segmented Thermoelectric Generators, Proceedings of 21st International Conference on Thermoelectrics, (IEEE, New York), p. 412
(PDF)
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Education
- B.S. in Physics at Rensselaer Polytechnic Institute, 2003
Summa Cum Laude (GPA 3.97)
Advisers: Profs. Peter Persans and Peter Kramer
Minor: Materials Science and Spanish
Semester Abroad - Spring 2002 - Valencia, Spain
- M.S. in Applied Physics at California Institute of Technology, 2005
(GPA 4.0)
- Ph.D. in Applied Physics at California Institute of Technology, May 2009
Thesis work in biophysics with Prof. Rob Phillips.
- Marine Biological Laboratory - Physiology Course 2006
- New England Biolabs Molecular Biology Summer School 2005
I must talk to you now!
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