InP-based quantum cascade lasers monolithically integrated onto silicon.

Lasing is reported for ridge-waveguide devices processed from a 40-stage InP-based quantum cascade laser structure grown on a 6-inch silicon substrate with a metamorphic buffer. The structure used in the proof-of-concept experiment had a typical design, including an Al0.78In0.22As/In0.73Ga0.27As strain-balanced composition, with high strain both in quantum wells and barriers relative to InP, and an all-InP waveguide with a total thickness of 8 µm. Devices of size 3 mm x 40 µm, with a high-reflection back facet coating, emitted at 4.35 µm and had a threshold current of approximately 2.2 A at 78 K. Lasing was observed up to 170 K. Compared to earlier demonstrated InP-based quantum cascade lasers monolithically integrated onto GaAs, the same laser structure integrated on silicon had a lower yield and reliability. Surface morphology analysis suggests that both can be significantly improved by reducing strain for the active region layers relative to InP bulk waveguide layers surrounding the laser core.

[Morphological and functional studies of the lacerated sciatic nerve in rats after using various suture technics]. / Badania morfologiczne i czynnosciowe przecietego nerwu kulszowego szczura po zastosowaniu róznych technik zespalania.

The course of regenerative processes was compared in rat sciatic nerve after its transection and anastomosis of the nerve. The nerves were united suturing the epineurium, laying sutures through the nerve trunk or were united with tissue adhesive. A comparison of the results of clinical, electromyographic and histological studies demonstrated a superiority of suturing through the epineurium over the remaining methods. Regeneration processes appeared in these cases earliest and in the end result these processes were most complete.

[Functional disorders following resection of the tongue and mouth floor]. / Die funktionellen Störungen nach Zungen- und Mundbodenresektion

On observing 20 patients who had underwent total tongue and floor-of-the-mouth resection, the authors stated difficulties in swallowing and breathing that in certain cases called for laryngectomy. To counteract these disorders, floor-of-the-mouth and tongue reconstruction was performed with the aid of an arterialized frontal flap, which resulted in essentially undisturbed functions.