Polypyrrole one-dimensional nanostructures (nanotubes, nanobelts and nanofibers) were prepared using three various dyes (Methyl Orange, Methylene Blue and Eriochrome Black T). Their high electrical conductivity (from 17.1 to 60.9 S cm-1), good thermal stability (in the range from 25 to 150 °C) and resistivity against ageing (half-time of electrical conductivity around 80 days and better) were used in preparation of lightweight and flexible composites with silicone for electromagnetic interference shielding in the C-band region (5.85-8.2 GHz). The nanostructures' morphology and chemical structure were characterized by scanning electron microscopy, Brunauer-Emmett-Teller specific surface measurement and attenuated total reflection Fourier-transform infrared spectroscopy. DC electrical conductivity was measured using the Van der Pauw method. Complex permittivity and AC electrical conductivity of respective silicone composites were calculated from the measured scattering parameters. The relationships between structure, electrical properties and shielding efficiency were studied. It was found that 2 mm-thick silicone composites of polypyrrole nanotubes and nanobelts shield almost 80% of incident radiation in the C-band at very low loading of conductive filler in the silicone (5% w/w). Resulting lightweight and flexible polypyrrole composites exhibit promising properties for shielding of electromagnetic interference in sensitive biological and electronic systems.

• MeSH
• azosloučeniny chemie   MeSH
• elektromagnetické záření * MeSH
• methylenová modř chemie   MeSH
• mikroskopie elektronová rastrovací MeSH
• nanostruktury chemie   účinky záření   ultrastruktura   MeSH
• nanotrubičky chemie   účinky záření   ultrastruktura   MeSH
• nanovlákna chemie   účinky záření   MeSH
• polymery chemie   účinky záření   MeSH
• pyrroly chemie   účinky záření   MeSH
• silikony chemie   účinky záření   MeSH
• Publikační typ
• časopisecké články MeSH

Five platinum(II) complexes bearing a (1,3-dibenzyl)imidazol-2-ylidene ligand but different leaving groups trans to it were examined for cytotoxicity, DNA and cell cycle interference, vascular disrupting properties, and nephrotoxicity. The cytotoxicity of complexes 3a-c increased with the steric shielding of their leaving chloride ligand, and complex 3c, featuring two triphenylphosphanes, was the most efficacious, with submicromolar IC50 concentrations. Complexes 3a-c interacted with DNA in electrophoretic mobility shift and ethidium bromide binding assays. The cationic complex 3c did not bind coordinatively to DNA but led to its aggregation, damage that is not amenable to the usual repair mechanisms. Accordingly, it arrested the cell cycle of melanoma cells in G1 phase, whereas cis-dichlorido[(1,3-dibenzyl)imidazol-2-ylidene](dimethyl sulfoxide) platinum(II) 3a induced G2/M phase arrest. Complex 3c also disrupted the blood vessels in the chorioallantoic membrane of fertilized chicken eggs. Ex vivo studies using precision-cut tissue slices suggested the nephrotoxicities of 3a-c to be clinically manageable.

• MeSH
• DNA účinky léků   MeSH
• heterocyklické sloučeniny chemie   farmakologie   MeSH
• lidé MeSH
• methan analogy a deriváty   chemie   MeSH
• nádorové buněčné linie MeSH
• protinádorové látky chemie   farmakologie   MeSH
• sloučeniny platiny chemie   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• nádory radioterapie   MeSH
• nukleární lékařství metody   MeSH
• radioterapie metody   MeSH
• Publikační typ
• učebnice MeSH

• Konspekt
• Učební osnovy. Vyučovací předměty. Učebnice
• Lékařské vědy. Lékařství
• NLK Obory
• radiologie, nukleární medicína a zobrazovací metody
• onkologie
• NLK Publikační typ
• kolektivní monografie