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Full-Text Articles in Physical Sciences and Mathematics
Enzyme Entrapment In Polyaniline Films Observed Via Florescence Anisotropy And Antiquenching, Louis R. Nemzer, Marissa Mccaffrey, Arthur J. Epstein
Enzyme Entrapment In Polyaniline Films Observed Via Florescence Anisotropy And Antiquenching, Louis R. Nemzer, Marissa Mccaffrey, Arthur J. Epstein
Louis R Nemzer
The facile entrapment of oxidoreductase enzymes within polyaniline polymer films by inducing hydrophobic collapse using phosphate buffered saline (PBS) has been shown to be a cost-effective method for fabricating organic biosensors. Here, we use fluorescence anisotropy measurements to verify enzyme immobilization and subsequent electron donation to the polymer matrix, both prerequisites for an effective biosensor. Specifically, we measure a three order of magnitude decrease in the ratio of the fluorescence to rotational lifetimes. In addition, the observed fluorescence antiquenching supports the previously proposed model that the polymer chain assumes a severely coiled conformation when exposed to PBS. These results help …
A Model Of Band-Pass Phenotypic Resistance In A Modified Beverton-Holt Framework, Louis R. Nemzer
A Model Of Band-Pass Phenotypic Resistance In A Modified Beverton-Holt Framework, Louis R. Nemzer
Louis R Nemzer
A new mathematical model of phenotypic bacterial resistance to a periodically applied antibiotic is presented. Using a modified Beverton–Holt framework, and without appealing to any explicit internal timescale or heritable mutations, we map the parameter-space regions corresponding to bacterial colony survival or extinction. It is demonstrated that band-pass behavior, in which colony survival occurs at intermediate – but not short or long – antibiotic application periods, is a possible regime for some initial population values if the bactericidal activity is sufficient. However, below this threshold value of antibiotic efficacy, a ‘‘fixed-point catastrophe’’ occurs, and colony extinction does not occur when …