Alginate – chitosan – alginate multilayer hydrogel encapsulation systems were investigated for
encapsulation of chondrocytes. Hydrogel is crosslinked due to ionic interaction between cationic
chitosan and anionic alginate, and additionally by calcium ions. Two types of chitosan with
molecular weight were investigated. Cells were encapsulated in two shape microcapsules, microbeads with diameter size 300 – 400 and 500 - 600 µm and fibres with diameter 500 - 600 µm. The
work provides a detailed examination of the impact of the microencapsulation process on the growth
of cells. The viability of chondrocytes can be influenced by the size of produced microcapsules,
while the shape of microcapsules has no important significance on cell viability. The applied
encapsulation methods do not contain harmful stages and create conducive conditions for cell
growth. A possible application area of the developed system is dressing and regeneration of
damaged joint cartilage.
The article presents a method for assessing emissions of harmful substances and noise from road and air transport, as well as a combined assessment of the emissions of these transport pollutants. The original analytical dependencies reflecting the emissions of harmful substances from road transport, developed as part of the EMITRANSYS project implemented at the Faculty of Transport of the Warsaw University of Technology, were taken into consideration, in which the unit values of the actual road emissions of harmful substances are a function of, among other things, route length or speed of the vehicles. However, the dependencies associated with noise emissions were taken from the applicable international guidelines for assessing environmental pollution by traffic noise.
The article also describes a case study in which the impact of Warsaw Chopin Airport on noise along the Warsaw road network and the entire Warsaw agglomeration was assessed. Analyses and discussions were carried out in the scope of the change in transport noise due to air operations carried out in the analysed area. As agreed, the combined impact of road and aircraft noise in the area under study is far more unfavourable than street noise alone. Thus, it can be seen that the assessment of noise levels carried out separately for individual modes of transport (in accordance with applicable regulations) should be supplemented with the assessment of traffic noise from all modes of transport – especially in the case of simulation tests of ecologically friendly changes in the area of transport.
The self-consistent optical-electrical-thermal-gain model of the oxide-confined edge-emitting diode laser has been used to simulate the room-temperature operation of the long-wavelength 1.3-µm quantum-dot (InGa)As/GaAs diode laser. The validityof the model has been verified using some experimental results for comparison. An impact of quantum-dot densityon laser operation characteristics as well as on temperature dependence of lasing threshold have been discussed.
This paper presents the results of a numerical analysis of nitride-based edge-emitting lasers with an InGaN/GaN active region designed for continuous wave room temperature emission of green and blue light. The main goal was to investigate whether the indium thin oxide (ITO) layer can serve as an effective optical confinement improving operation of these devices. Simulations were performed with the aid of a self-consistent thermal-electrical-optical model. Results obtained for green- and blue-emitting lasers were compared. The ITO layer in the p-type cladding was found to effectively help confine the laser mode in the active regions of the devices and to decrease the threshold current density.