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We have made a first investigation on the resonances in two electron systems in various model plasma environments. The 2s2 1Se autoionization resonance state in the helium atom is determined by calculating the density of resonance states using the stabilization method. A screened Coulomb potential obtained from the Debye model is used to represent the interaction between the charged particles. A correlated wave function has been used to represent the correlation effect between the three charge particles. The calculated resonance energies and widths for various Debye parameters ranging from infinity to a small value along with the ground state energies are reported.

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We have investigated a novel compound, 3,6-bis[2-(1-methylpyridinium)vinyl]carbazole diiodide (BMVC), for inhibiting telomerase activity and distinguishing human lung H1299 and oral Ca9-22 cancer cells from lung IMR90 and skin Detroit-551 normal fibroblast cells. The telomeric repeat amplification protocol (TRAP) assay shows that the concentration of BMVC that inhibits 50% of the telomerase activity (IC50) is ca. 0.05 microM. On the other hand, the cell-viability assay indicates that the cytotoxicity was less than 15% to the H1299 and Ca9-22 cancer cells, and almost negligible to the MRC-5 and Detroit-551 normal cells after incubation with 0.5 microM BMVC for 72 h. The low concentration of 0.05 microM of BMVC can inhibit telomerase activity but does not have general toxic effects to normal cells, implying that BMVC is a promising telomerase inhibitor. Moreover, wide-field fluorescence images of 0.1 microM BMVC-treated cells show bright fluorescence spots in the nuclei of the most H1299 and Ca9-22 cancer cells. Interestingly, similar fluorescence spots are hardly observed in the nuclei of the IMR90 and Detroit-551 normal cells, implying that BMVC might be a useful marker to distinguish tumor cells and normal cells.

We study equilibration of strongly coupled ions in an ultracold neutral plasma produced by photoionizing laser-cooled and trapped atoms. By varying the electron temperature, we show that electron screening modifies the equilibrium ion temperature. Even with few electrons in a Debye sphere, the screening is well described by a model using a Yukawa ion-ion potential. We also observe damped oscillations of the ion kinetic energy that are a unique feature of equilibration of a strongly coupled plasma.

We report optical absorption imaging of ultracold neutral strontium plasmas. The ion absorption spectrum determined from the images is Doppler broadened and thus provides a quantitative measure of the ion kinetic energy. For the particular plasma conditions studied, ions heat rapidly as they equilibrate during the first 250 ns after plasma formation. Equilibration leaves ions on the border between the weakly coupled gaseous and strongly coupled liquid states. On a longer time scale of microseconds, pressure exerted by the trapped electron gas accelerates the ions radially.

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