The present report describes development of hexamethonium complexes based on fullerene C60. Hexamethonium has a limited penetration into CNS and therefore can antagonize central effects of nicotine only when given at high doses. In the present studies conducted in laboratory rodents, intraperitoneal administration of hexamethonium-fullerene complexes blocked effects of nicotine (convulsions and locomotor stimulation). When compared to equimolar doses of hexamethonium, complexes of hexamethonium with derivatives of fullerene C60 were 40 times more potent indicating an enhanced ability to interact with central nicotine receptors. Thus, fullerene C60 derivatives should be explored further as potential carrier systems for polar drug delivery into CNS.
Semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide and emitting in the wavelength range 1.0 -1.1 mm are studied. It is found that the intensity of spontaneous emission from the active region increases with increasing pump current above the lasing threshold and that this is caused by a growth in the concentration of charge carriers in the active region due to the modal gain enhancement needed to compensate for the growing internal optical loss at high pulsed pump currents. It is shown that the increase in the internal optical loss with increasing pulsed pump current is one of the main reasons for saturation of the light -current characteristics of high-power semiconductor lasers.
A buried-mesa AlGaAs/GaAs/GaInAs laser heterostructure emitting at a wavelength of 1050 nm is formed on a GaAs substrate by MOCVD. Mesa-stripe laser diodes with an aperture of 100 μm based on the obtained heterostructure are fabricated and studied. The internal optical losses of the laser diodes are 2.4 cm−1. The output powers in both directions achieved at a cavity length of 2900 μm in the cw and pulsed regimes were 2.1 and 23 W, respectively.
Cooperative software engineering typically involves many actors and resources that cooperate in a complex distributed and heterogeneous world. In the DIPS (Distributed Integrated Process Services) project, a three-dimensional model is used for the definition, enactment and tracing of software development processes, which expresses both structure and evolution of such processes. This paper discusses how an optimal architecture was evaluated to implement the process model in a process support framework. Process-specific and general requirements are identified, and expected usage patterns of a DIPS-based environment are analysed. A set of potential architecture variants is proposed, and implications of the requirements and usage patterns on the variants are discussed qualitatively. An evaluation of the architecture alternatives leads to the design of the hybrid DIPS architecture based on distributed heterogeneous objects. The prototype DIPS implementation is briefly outlined.
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