sam | conferences, science community, seminars
Although I missed Sunday and Monday, I did see some cool talks today:
- Watt Webb‘s talk was a typical Webb talk: cool pictures, great voice, and a hodgepodge of info. He spoke mostly about lipid rafts in cell membranes.
- Stefan Hell had some spectacular images from his super-resolution work (STED and RESOLFT and other acronyms). His newer work on fast “PALMIRA“—stochastic single-fluorophore photoswitching imaging, like PALM/STORM—and multicolor imaging is really impressive. He added a square-root factor to the denominator of the Abbe diffraction limit: (1 + I/Is)1/2, where Is is the threshold intensity above which you get sub-diffraction imaging. Hell also talked about 3D PALMIRA using slicing 2-photon excitation of new photoactivatable rhodamines they developed!
- Bo Huang is a postdoc in Xiaowei Zhuang’s lab; I know him from when he was a graduate student in Dick Zare’s lab. He showed some truly beautiful three-color PALM images of microtubules and clathrin in cells (fixed, I think). They have a brand-new paper in Science with all these great images, check it out! Viewing just the TIR image, one would conclude that some clathrin pits were associated with microtubules; the PALM image revealed that the clathrin was only near the microtubles, but not actually colocalized (see image above). As far as the mechanism of cyanine dye photoswitching, Bo said that it was triplet related (dependent on heavy-ion concentration), thiol related (BME, L-glutathione, and cysteine all worked), and not isomerization (not dependent on viscosity). Xiaowei said that Roger Tsien thinks that it is nucleophilic attack by the reductants in the oxygen scavenger.
- Michel Orrit used some sensitive interferometric and heterodyne experiments to measure the absorption of single gold nanoparticles (~10 nm) at room temperature. These particles absorb a lot of light, but are not very luminescent: so they efficiently heat the surroundings, allowing for photothermal detection. Some cool work, but hard to relate to cellular imaging.
I’ll update more tomorrow. Prepare for Sunney Xie, Daniel Chiu, Antoine van Oijen, and much more!
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