Cancer-selective antiproliferative activity is a general property of some G-rich oligodeoxynucleotides

Oligodeoxynucleotide libraries containing randomly incorporated bases are used to generate DNA aptamers by systematic evolution of ligands by exponential enrichment (SELEX). We predicted that combinatorial libraries with alternative base compositions might have innate properties different from the standard library containing equimolar A + C + G + T bases. In particular, we hypothesized that G-rich libraries would contain a higher proportion of quadruplex-forming sequences, which may impart desirable qualities, such as increased nuclease resistance and enhanced cellular uptake. Here, we report on 11 synthetic oligodeoxynucleotide libraries of various base combinations and lengths, with regard to their circular dichroism, stability in serum-containing medium, cellular uptake, protein binding and antiproliferative activity. Unexpectedly, we found that some G-rich libraries (composed of G + T or G + C nucleotides) strongly inhibited cancer cell growth while sparing non-malignant cells. These libraries had spectral features consistent with G-quadruplex formation, were significantly more stable in serum than inactive libraries and showed enhanced cellular uptake. Active libraries generally had strong protein binding, while the pattern of protein binding suggested that G/T and G/C libraries have distinct mechanisms of action. In conclusion, cancer-selective antiproliferative activity may be a general feature of certain G-rich oligodeoxynucleotides and is associated with quadruplex formation, nuclease resistance, efficient cellular uptake and protein binding

Wpływ temperatury na dynamiczne zachowanie turbogeneratora

Temperature fields in electric energy generation may lead to the mechanical disbalance of an already balanced rotor. The authors collected information in a number of Serbian steam power plants and they realized the existence of the problem. On the grounds of the relevant physical aspects they propose a mathematical model for identifying temperature fields in a turbo-generator rotor, and they suggest the optimum control by which the unwanted effects are eliminated.Pole temperaturowe w wytwarzaniu energii elektrycznej może prowadzić do nierównowagi mechanicznej wirnika będącego w stanie równowagi. Autorzy zebrali informacje w wielu elektrowniach cieplnych na terenie Serbii i stwierdzili istnienie tego problemu. Biorąc pod uwagę istotne czynniki fizyczne zaproponowano model matematyczny dla celów identyfikacji pól temperaturowych w wirniku turbogeneratora i na jego podstawie dobrano sposób sterowania optymalny ze względu na eliminacje niepożądanych zjawisk