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- ItemAutofluorescence guided welding of heart tissue by laser pulse bursts at 1550 nm(Washington, DC : Optica, 2020) Litvinova, Karina; Chernysheva, Maria; Stegemann, Berthold; Leyva, FranciscoWound healing and other surgical technologies traditionally solved by suturing and stapling have recently been enhanced by the application of laser tissue welding. The usage of high energy laser radiation to anastomose tissues eliminates a foreign body reaction, reduces scar formation, and allows for the creation of watertight closure. In the current work, we show that an ultrafast pulsed fibre laser beam with 183 µJ·cm−2 energy fluence at 1550 nm provides successful welding of dissected chicken heart walls with the tensile strength of 1.03±0.12 kg·cm−2 equal to that of native tissue. The welding process was monitored employing fluorescence spectroscopy that detects the biochemical composition of tissues. We believe that fluorescence spectroscopy guided laser tissue welding is a promising approach for decreasing wound healing times and the avoiding risks of postoperative complications.
- ItemMeasurement of diamond nucleation rates from hydrocarbons at conditions comparable to the interiors of icy giant planets(Woodbury, NY : Inst., 2020) Schuster, A.K.; Hartley, N.J.; Vorberger, J.; Döppner, T.; Van Driel, T.; Falcone, R.W.; Fletcher, L.B.; Frydrych, S.; Galtier, E.; Gamboa, E.J.; Gericke, D.O.; Glenzer, S.H.; Granados, E.; MacDonald, M.J.; MacKinnon, A.J.; McBride, E.E.; Nam, I.; Neumayer, P.; Pak, A.; Prencipe, I.; Voigt, K.; Saunders, A.M.; Sun, P.; Kraus, D.We present measurements of the nucleation rate into a diamond lattice in dynamically compressed polystyrene obtained in a pump-probe experiment using a high-energy laser system and in situ femtosecond x-ray diffraction. Different temperature-pressure conditions that occur in planetary interiors were probed. For a single shock reaching 70 GPa and 3000 K no diamond formation was observed, while with a double shock driving polystyrene to pressures around 150 GPa and temperatures around 5000 K nucleation rates between 1029 and 1034m-3 s-1 were recorded. These nucleation rates do not agree with predictions of the state-of-the-art theoretical models for carbon-hydrogen mixtures by many orders of magnitude. Our data suggest that there is significant diamond formation to be expected inside icy giant planets like Neptune and Uranus. © 2020 authors. Published by the American Physical Society.