Tristan Ursell's Research and Recreation Page
[ Contact Info | CV | Biophysics Research | Teaching | Recreation | Previous Research | Education | E-mail Me Now ]
We're good to go!
Wisdom for Physicists:
"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
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Outdated personal homepage that has some good links and pictures.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
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.
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)
The role of membrane-protein interactions in voltage-gated ion channel gating
Dan Reeves, Tristan Ursell, Pierre Sens, Jane' Kondev and Rob Phillips (2007) submitted to Biophys J.
(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 10um.
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)
Dimpling Instability and Interaction between Lipid Domains
Tristan Ursell and Rob Phillips
(Request Preprint)
Dynamic Morphologies and Coalescence of Lipid Domains
Tristan Ursell and Rob Phillips
(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:
Monte Carlo simulation of lipid phase separation.
Quench from T = infinity shows spinodal decomposition, Ostwald ripening and domain coalescence.
The box is ~178nm x 146nm, and the coordination number is q=6.
An interesting way to view the dynamics is by plotting the time average and standard deviation in different colors.
Domains that look mostly green Ostwald ripened, two close domains surrounded by green coalesced.
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:
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.
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)
The role of membrane-protein interactions in voltage-gated ion channel gating
Dan Reeves, Tristan Ursell, Pierre Sens, Jane' Kondev and Rob Phillips (2007) submitted to Biophys J.
(PDF)
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 10um.
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)
Dimpling Instability and Interaction between Lipid Domains
Tristan Ursell and Rob Phillips
(Request Preprint)
Dynamic Morphologies and Coalescence of Lipid Domains
Tristan Ursell and Rob Phillips
(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:
Monte Carlo simulation of lipid phase separation.
Quench from T = infinity shows spinodal decomposition, Ostwald ripening and domain coalescence.
The box is ~178nm x 146nm, and the coordination number is q=6.
An interesting way to view the dynamics is by plotting the time average and standard deviation in different colors.
Domains that look mostly green Ostwald ripened, two close domains surrounded by green coalesced.
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.
In conjunction with the Van Oudenaarden Lab @ MIT
ASCB 2006 Poster (PDF)
Pluggin away.
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
- Marine Biological Laboratory - Physiology Course - Summer 2007
- Physical Biology Bootcamp
2005, 2006 and 2007. In June 2008 at the National University of Singapore!
Some recent fun videos and pictures created during the bootcamp:
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 s:
Protocol for electroformation of giant unilamellar vesicles.
Tutorial on derivation and solutions of the diffusion equation (with derivation of mean first passage time - coming soon).
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) - Difficult to use without the accompanying talk.
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)
- 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.
- 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.
- The story of my life.
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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, expected 2008
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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All videos, pictures, and downloadable material on this website are property of Tristan Ursell (c) 2005-2008
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