Pump–probe study of the reconstruction of helium surrounding a tetracene molecule inside a helium droplet
The ::: electronic spectra of single tetracene molecules and tetracene–Ar complexes embedded in large (≃103–104) superfluid ::: helium droplets have been investigated with a pump–probe technique. New sharp (δν≈0.5 cm−1) red-shifted (Δν≈1–2 cm−1) features are obtained in the probe laser spectra indicating a rapid (Δt<20 ns) reconstruction of the He environment ::: upon electronic excitation. These new structures are interpreted with a simple modified bubble-like model. Evidence for a rise in the droplet temperature induced by the pump laser pulse is obtained ::: from a broadening ::: of the phonon wing ::: measured by the probe laser.
SUMMARY ::: One major challenge of the post-sequencing era of the human genome project will be the functional annotation of the non-coding portion of the genome, in particular gene regulatory sequences. We have developed a new web-based tool, TFBScluster, which performs genome-wide identification of transcription factor binding site clusters that are conserved in multiple mammalian genomes. Clusters representing candidate gene regulatory elements can be filtered further, based on the presence or absence of additional user-defined DNA sequence motifs or by constraining the orientation or order of binding sites. Comprehensive results files, returned by email, are designed to facilitate experimental validation of computationally identified candidate gene regulatory sequences. TFBScluster, therefore, has the potential to contribute to deciphering transcriptional networks that regulate a wide range of mammalian developmental processes.