Controllable 3D atomic Brownian motor in optical lattices

7 pages, 4 figures. Presented at the conference "Theoretical and Experimental Foundations of Recent Quantum Technologies" (Durban, South Africa)International audienceWe study a Brownian motor, based on cold atoms in optical lattices, where atomic motion can be induced in a controlled manner in an arbitrary direction, by rectification of isotropic random fluctuations. In contrast with ratchet mechanisms, our Brownian motor operates in a potential that is spatially and temporally symmetric, in apparent contradiction to the Curie principle. Simulations, based on the Fokker-Planck equation, allow us to gain knowledge on the qualitative behaviour of our Brownian motor. Studies of Brownian motors, and in particular ones with unique control properties, are of fundamental interest because of the role they play in protein motors and their potential applications in nanotechnology. In particular, our system opens the way to the study of quantum Brownian motors

Antinociception Depends on the Presence of G Protein γ\u3csub\u3e2\u3c/sub\u3e- Subunits in Brain

We have shown previously [Hosohata, K., Logan, J.K., Varga, E., Burkey, T.H., Vanderah, T.W., Porreca, F., Hruby, V.J., Roeske, W.R., Yamamura, H.I., 2000. The role of the G protein γ2 subunit in opioid antinociception in mice. Eur. J. Pharmacol. 392, R9-R11] that intracerebroventricular (i.c.v.) treatment of mice with a phosphorothioate oligodeoxynucleotide antisense to the γ2 subunit (Gγ2) of the heterotrimeric G proteins (antisense ODN) significantly attenuates antinociception by a δ-opioid receptor agonist. In the present study, we examined the involvement of Gγ2 in antinociception mediated by other (μ- or κ-opioid, cannabinoid, α2-adrenoreceptor) analgesic agents in a warm (55°C) water tail-flick test in mice. Interestingly, i.c.v. treatment with the antisense ODN attenuated antinociception by each analgesic agent. Missense phosphorothioate oligodeoxynucleotide treatment, on the other hand, had no effect on antinociception mediated by these agonists. The antinociceptive response recovered in 6 days after the last antisense ODN injection, indicating a lack of nonspecific tissue damage in the animals. These results suggest a pervasive role for the G protein γ2 subunits in supraspinal antinociception