Lectures

EINSTEIN - Centenary Commemoration of Einstein's Annus Mirabilis

Georgia Tech Special Lecture for World Year of Physics, October 27, 2005

 

The World Year of Physics 2005 was a United Nations endorsed, international celebration of physics. Events throughout the year highlighted the vitality of physics and its importance in the coming millennium, and commemorated the pioneering contributions of Albert Einstein in 1905. Through the efforts of a worldwide collaboration of scientific societies, the World Year of Physics brought the excitement of physics to the public and inspired a new generation of scientists. The School of Physics at Georgia Tech presented a special lecture by Regents Professor Ron Fox reviewing Einstein's important work. Dr. Fox reviewed Einstein's early life up to his year of wonder, 1905. The significance of Einstein's 1905 contributions to the photoelectric effect, Brownian motion, and the special theory of relativity was discussed. Einstein's own account of what motivated him was addressed.

 

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Ron Fox Einstein lecture

 

 


Rectified Brownian Motion in Sub-Cellular Biology

Fermilab Colloquium Series, November 8, 2006

 

Thermal energy becomes increasingly important as we move down in scale from a macroscopic organism to a molecule. At the molecular scale, thermal energy can be used constructively by cells through a mechanism called rectified Brownian motion, without violating the second law of thermodynamics. This mechanism will be explained and illustrated in this talk.
The paradigm for the mechanism of rectified Brownian motion in cells is the ubiquinone cycle that occurs centrally in the energy metabolism of bacteria, animals and plants. The ubiquinone cycle is especially interesting since it couples electron currents to proton currents, thereby transducing electrical energy into proton energy. The proton energy is then used to generate phosphate energy that is used by cells to drive many processes including synthesis of polymers, such as proteins and the polynucleotides DNA and RNA.
After explaining how rectified Brownian motion is responsible for the ubiquinone cycle, it will be shown that members of a class of rotary enzymes, common to all cells, are also examples of rectified Brownian motion. The talk will conclude with a description of the mechanism of action of a motor protein, kinesin, that “walks” on microtubule tracts inside of cells. Kinesins are responsible for separating chromosomes during cell division, and for transporting neurotransmitters down the axons of nerves, among other functions. They are another example of rectified Brownian motion.

Brownian motion image

Picture redrawn from
Ronald Vale and Ronald Milligan.
Science
Vol. 288, pp. 88–95 (2000)

 

 

 

 

 

 

 

 

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