Long-Range Interactions and the Oscillator Strength for the 11u,10u+\text{}^{1}1_{u}, \text{}^{1}0_{u}^{+} ← X 10g+\text{}^{1}0_{g}^{+} Transitions in Zn2\text{}_{2}

The interaction potentials for Zn$\text{}_{2}$ electronic states $\text{}^{1}1\text{}_{u}$ and $\text{}^{1}0_{u}^{+}$ correlated with (4 $\text{}^{1}P_{1}$+4 $\text{}^{1}S_{0}$) asymptote in the long-range region (10-25) Å and the oscillator strength f for the absorption transition to these states are derived experimentally from a careful analysis of the self-broadened resonance 213.8 nm line of Zn. It is found that although the interatomic interactions at so long distances are dominated by resonance potential of the form C$\text{}_{3}$/R$\text{}^{3}$ resulting in the Lorentzian line shape, the parameter C$\text{}_{3}$ and thus f value significantly decrease with R decreasing. This effect proved to be a linear function of R$\text{}^{-1}$ yielding the oscillator strength for the considered line f$\text{}_{0}$=1.456 $\pm$ 0.010 from $R \rightarrow \infty$ extrapolation. This value seems to be the most accurate experimental result as yet and shows that the best theoretical values for this quantity are overestimated. It is suggested that the long-range behaviour of the potential energy curves observed here for the first time represents the effective potentials including dominating resonance interactions and a possible slight contribution of the dispersion interactions as well as the R-dependent spin-orbit interaction

Extracellular MIF, but not its homologue D-DT, promotes fibroblast motility independent of its receptor CD74/CD44

Macrophage migration inhibitory factor (MIF) and its homologue D-dopachrome tautomerase (D-DT) are widely expressed pro-inflammatory cytokines with chemokine-like functions that coordinate a wide spectrum of biological activities, such as migration. Here, we biotin-tagged intracellular MIF/D-DT in vivo to identify important cytosolic interactors and found a plethora of actin cytoskeleton-associated proteins. Although the receptor complex between CD74 and CD44 (CD74/CD44) is essential for signalling transduction in fibroblasts via extracellular MIF/D-DT, our interactome data suggested direct effects. We, thus, investigated whether MIF/D-DT can modulate cell migration independently of CD74/CD44. To distinguish between receptor- and non-receptor-mediated motility, we used fibroblasts that are either deficient or that express CD74/CD44 proteins, and treated them with recombinant MIF/D-DT. Interestingly, only MIF could stimulate chemokinesis in the presence or absence of CD74/CD44. The pro-migratory effects of MIF depended on lipid raft/caveolae-mediated but not clathrin-mediated endocytosis, on its tautomerase activity and, probably, on its thiol protein oxidoreductase activity. As MIF treatment restrained actin polymerisation in vitro, our findings establish a new intracellular role for MIF/D-DT in driving cell motility through modulation of the actin cytoskeleton

Coincidence resolution time of two small scintillators coupled to high quantum-efficiency photomultipliers in a PET-like system

The lower limit of the time resolution for a positron emission tomography (PET) system has been measured for two scintillator types, LYSO:Ce and LuAG:Pr. Small dimension crystals and ultra bi-alkali phototubes have been used in order to increase the detected scintillation photons. Good timing resolutions of 118 ps and 223 ps FWHM have been obtained for two LYSO and two LuAG, respectively, exposed to a 22Na source