No abstract

Bacteria and fungi, isolated from United States Air Force (USAF) aviation fuel samples, were identified by gas chromatograph fatty acid methyl ester (GC-FAME) profiling and 16S or 18S rRNA gene sequencing. Thirty-six samples from 11 geographically separated USAF bases were collected. At each base, an above-ground storage tank, a refueling truck, and an aircraft wing tank were sampled at the lowest sample point, or sump, to investigate microbial diversity and dispersion within the fuel distribution chain. Twelve genera, including four Bacillus species and two Staphylococcus species, were isolated and identified. Bacillus licheniformis, the most prevalent organism isolated, was found at seven of the 11 bases. Of the organisms identified, Bacillus sp., Micrococcus luteus, Sphinogmonas sp., Staphylococcus sp., and the fungus Aureobasidium pullulans have previously been isolated from aviation fuel samples. The bacteria Pantoea ananatis, Arthrobacter sp., Alcaligenes sp., Kocuria rhizophilia, Leucobacter komagatae, Dietza sp., and the fungus Discophaerina fagi have not been previously reported in USAF aviation fuel. Only at two bases were the same organisms isolated from all three sample points in the fuel supply distribution chain. Isolation of previously undocumented organisms suggests either, changes in aviation fuel microbial community in response to changes in aviation fuel composition, additives and biocide use, or simply, improvements in isolation and identification techniques.

Peptide-mediated internalization and organelle targeting of quantum dots.

A detailed procedure for growing LC templated PEDOT films on ITO is given elsewhere [10]. Absorption spectra were collected on a Cary 500 UV/VIS/NIR spectrometer in double beam mode with a linearly polarizing filter (Edmund Optics A43-785) mounted on a rotating goniometer in the sample beam. Spectra were normalized to the baseline absorption of the filter and the ITO substrate. Substrates for four-probe conductivity measurements were photolithographically patterned using Clariant AZ1518 photoresists and the exposed ITO was removed with HCl. Patterned substrates were cleaned and polymerized as above. After washing and removal of the LC template, PEDOT films were cast with a 20 wt.-% solution of a thermosetting poly(amide-imide) (42 827-2, Aldrich) in 1-methyl-2-pyrrolidinone (NMP), heated to 150 C for 2 h; the resulting film was lifted off, transferring the PEDOT film from ITO to the insulating polyamide substrate. For multi-domain film conductivity measurements, Au electrodes were e-beam evaporated through a shadow mask across narrow strips of PEDOT. For single domain measurements, probes were contacted directly to the PEDOT film (Fig. 3a). A Keithley 2400 source meter was used to measure I±V curves for LC templated and nontemplated PEDOT, and both exhibited ohmic behavior. Uncertainty values given are a 95 % confidence interval for the mean based on ten samples. Film thickness was measured with a Tencor P10 profilometer. 30 nm thick PEDOT films for XPS were polymerized on Au coated Si substrates and studied using an Omicron ESCA Probe XPS with an Al Ka source operating at 14 kV. Binding energies were calibrated using the Au 4f peak (84.0 eV). After background subtraction, relative atomic composition was determined by integrating the C 1s (286.0 eV), S 2p (163.7 eV) and Cl 2p (200.4 eV) peaks and multiplying by instrument sensitivity factors determined for C, S, and Cl from known standards.