A spermine-like polymer was synthesized via reversible addition-fragmentation chain transfer polymerization as a potential endosomal escaping agent. A new methacrylate monomer, 2-((tertbutoxycarbonyl)(2-((tert-butoxycarbonyl)amino)ethyl)amino)ethylmethacrylate (BocAEAEMA), was prepared and then polymerized via RAFT polymerization at constant monomer or initiator concentration increase in M n with monomer conversion was also observed. P(BocAEAEMA)s with controlled molecular weights and narrow molecular weight distributions were obtained. The in vitro cytotoxicity and proton sponge capacity of deprotected polymers P(AEAEMA) were investigated in comparison with a widely used endosomal-disruptive polymer, PEI. P(AEAEMA)s were found to possess proton sponge capacity comparable with PEI. More importantly, P(AEAEMA)s were not toxic on NIH 3T3 cells at concentrations where PEI (25 kDa) was highly toxic (0.4 mM and above). P(AEAEMA) was able to fully condense a DNA fragment at nitrogen/phosphate (N/P) ratios of 10 and above, as evidenced by gel electrophoresis. P(BocAEAEMA) was then chain-extended with a model sugar monomer, mannose-acrylate (ManAc), to yield P(AEAEMA)-b-P(ManAc) block copolymers, to potentially provide cell-recognition ability to the polyplex particles. Although the presence of the P(ManAc) block partially inhibited the interaction of P(AEAEMA) with DNA, P(AEAEMA) 13 -b-P(ManAc) 7 was able to form polyplexes with DNA at N/P ratios ranging between 20/1 and 2/1. Dynamic light scattering measurements showed that while P(AEAEMA) (M n ¼ 5.5 kDa) and DNA formed polyplex particles having a hydrodynamic diameter (D h ) of 125 AE 51 nm, P(AEAEMA) 13 -b-P(ManAc) 7 and DNA formed particles with a smaller D h of 38 AE 10 nm.
This study examines the literature of double-skin facade systems over the last decade, and, with the help of tables and graphics, investigates their advantages and disadvantages. Moreover, a detailed comparison is made between double skin façade systems. The results of the study show that the greatest advantage (95%) of double skin facade systems is their provision of natural ventilation. Other advantages are highlighted according to their percentage as follows: An increase in interaction between user and environment because of the high proportion of transparency, support of heat and sound insulation, reduction in heat transmission and solar heat gain coefficient, an increase in thermal comfort, allowance of solar control elements between the two facade spaces, and protection of these elements from external environment conditions. The most commonly accepted disadvantage (72%) is overheating in the air space of the two facades. Other disadvantages are highlighted according to their percentage as follows: Problems related to a decrease in the amount of daylight entering the building, high investment costs, additional maintenance and repair costs, fire, and acoustic problems. In our country, architectural design decisions related to overheating must be taken so as to provide a positive contribution to energy performance and the applicability of these systems.
This study examines the literature of double-skin facade systems over the last decade, and, with the help of tables and graphics, investigates their advantages and disadvantages. Moreover, a detailed comparison is made between double skin façade systems. The results of the study show that the greatest advantage (95%) of double skin facade systems is their provision of natural ventilation. Other advantages are highlighted according to their percentage as follows: An increase in interaction between user and environment because of the high proportion of transparency, support of heat and sound insulation, reduction in heat transmission and solar heat gain coefficient, an increase in thermal comfort, allowance of solar control elements between the two facade spaces, and protection of these elements from external environment conditions. The most commonly accepted disadvantage (72%) is overheating in the air space of the two facades. Other disadvantages are highlighted according to their percentage as follows: Problems related to a decrease in the amount of daylight entering the building, high investment costs, additional maintenance and repair costs, fire, and acoustic problems. In our country, architectural design decisions related to overheating must be taken so as to provide a positive contribution to energy performance and the applicability of these systems.
Abstract. The morphology, composition, optical, thermal and mechanical properties of a commercial pearlescent and multilayer biaxially oriented polypropylene (BOPP) films were determined. The structure and orientation of BOPP films were confirmed by FTIR spectroscopy, X-ray diffraction and EDX analysis. The films surface roughness was determined by AFM method. The tensile strength of the films was determined in machine and transverse directions.
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