Continuous-wave operation of GaInAs-AlGaAsSb quantum cascade lasers

We report on the demonstration of continuous-wave (CW) operation of GaInAs-AlGaAsSb quantum cascade (QC) lasers. By placing a 2.5-/spl mu/m-thick gold layer on both sides of the laser ridge to extract heat from the active region in the lateral direction, together with mounting the device epilayer down, we have achieved CW operation of GaInAs-AlGaAsSb QC lasers composed of 25 stages of active/injection regions. The maximum CW operating temperature of the lasers is 94 K, and the emission wavelength is around /spl lambda//spl sim/4.65 /spl mu/m. For a device with the size of 10/spl times/2000 /spl mu/m/sup 2/, the CW optical output power per facet is 13 mW at 42 K and 4 mW at 94 K. The CW threshold current density is 1.99 kA/cm/sup 2/ at 42 K, and 2.08 kA/cm/sup 2/ at 94 K, respectively.     

Risks and benefits of using Marlex mesh in chest wall reconstruction

The records of 101 patients who had undergone chest wall reconstruction both with and without stabilization of the chest wall by Marlex mesh were reviewed to see if Marlex reduced ventilator dependence and hospital stay, and to determine whether the use of Marlex was associated with any increased risk of infection. In 40 patients in whom Marlex was used, the mean number of days on postoperative ventilator support was 0.8, and mean hospital stay was 9.7 days. In 61 patients in whom Marlex was not used, the mean number of days on ventilator support was 4.9, and mean hospital stay was 17.5 days. These differences were statistically significant (p = 0.03, p = 0.006). Two patients in the Marlex-stabilized group (5%) developed wound infections, but these were preceded by ischemic necrosis of overlying flaps. None of the patients without Marlex developed wound infections. That difference was not statistically significant. We conclude that the use of Marlex in chest wall reconstruction does not significantly increase the risk of wound infection, provided that overlying tissues are properly vascularized and remain viable, and that synthetic mesh does improve chest wall stability and reduce ventilator dependence and overall hospital stay.     

Learning and chronobiological regulation following experimental damage to the coronary-artery wall of albino rats]

Forty male albino rats were used to study the relationship between experimentally (concentrated hydrochloric acid) produced local structural changes of the coronary artery wall and central nervous information processing and chronobiological events, respectively. The alterations of the coronary arteries caused by this treatment did not produce infarction but initiated on the whole length of the arterial branch proliferative processes that are complete within 12 weeks following the intervention. Central nervous information processing and chronoregulatory processes showed, immediately after exposure to hydrochloric acid, pronounced malfunctions followed by a stage of hyperreactivity (4 weeks following the damage). At 8 weeks from the intervention, the parameters of information processing and chronobiological events of the CNS again equalled the control values. Since the central nervous functions were back to normal earlier than the structural alterations, the results are interpreted as reflecting CNS-controlled interactions between the complex of visceral afference and efference, the regulation of which is determined by the CNS after coronary damage in such a way as to restore the adaptational capacity of the organism by a predominance of sanogenetic processes.