Biomedical subjects
Publications and source records attributed to D Kracht.
We report experimental and numerical results on the dynamics and propagation of parabolic pulses in a passively mode-locked ytterbium-doped fiber laser. Experimental data and numerical simulations are shown to match. Particular importance is attached to the pulse-shaping process in the different sections of the resonator. The paramount role of the gain fiber and saturable absorber in the laser is explicated.
A photophase of 18 hrs interrupts the annual anecdysis of Orconectes limosus, which does not constitute an irrefutable evidence of a photoperiodic control in the cessation of anecdysis, since molts are also induced during the annual rest by an abnormally high temperature after a stay at low temperature. On the contrary, long photophases (18 and 24 hrs), dispensed from the beginning of the molting period, do not inhibit the start of the anecdysis of adults on the express condition that the covers are reconstituted.
Polylactic membranes were evaluated for vertical ridge augmentation around immediate implants in periodontally compromised extraction sites. Ligature-induced periodontitis was produced in 10 adult beagle dogs. The periodontium was allowed to heal for 6 weeks. All premolar teeth were extracted and three implants were placed immediately into the extraction sockets on either side of the mandible so that the polished cone extended above the alveolar bone level. On one side of the mandible, the implants were covered with a 0.2-mm-thick polylactic membrane (DL-lactide-co-trimethylene carbonate in a ratio of 7:3). Histologic and morphometric analyses performed after 3 and 5 months revealed that the membrane group did not exhibit significantly greater bone-implant contact than the controls. The occurrence of dehiscences correlated significantly with use of the membrane. Use of the membrane was associated with significantly less peri-implant bone height after 5 months. No remnants of the membrane material could be identified after 3 or 5 months, indicating rapid resorption during the first weeks of implantation. The tested membrane material did not fulfill the requirements of resorption kinetics and space maintenance for guided bone regeneration in vertical ridge augmentation.