Field Scanner Design for MUSTANG of the Green Bank Telescope

MUSTANG is a bolometer camera for the Green Bank Telescope (GBT) working at a frequency of 90 GHz. The detector has a field of view of 40 arcseconds. To cancel out random emission change from atmosphere and other sources, requires a fast scanning reflecting system with a few arcminute ranges. In this paper, the aberrations of an off-axis system are reviewed. The condition for an optimized system is provided. In an optimized system, as additional image transfer mirrors are introduced, new aberrations of the off-axis system may be reintroduced, resulting in a limited field of view. In this paper, different scanning mirror arrangements for the GBT system are analyzed through the ray tracing analysis. These include using the subreflector as the scanning mirror, chopping a flat mirror and transferring image with an ellipse mirror, and chopping a flat mirror and transferring image with a pair of face-to-face paraboloid mirrors. The system analysis shows that chopping a flat mirror and using a well aligned pair of paraboloids can generate the required field of view for the MUSTUNG detector system, while other systems all suffer from larger off-axis aberrations added by the system modification. The spot diagrams of the well aligned pair of paraboloids produced is only about one Airy disk size within a scanning angle of about 3 arcmin.Comment: 7 pages, 9 figure

Stability and viability of Neisseria gonorrhoeae in various solutions and buffers.

The stability and viability of Neisseria gonorrhoeae WP (T4) was tested in a variety of buffers and solutions, many of which are commonly used in gonococcal research. Each solution was tested at room temperature for its ability to maintain stability and viability of gonococci in concentrated suspensions and to maintain viability of gonococci in dilute suspensions. The 14 buffers and solutions tested could be divided into four groups based upon these criteria. Only a few solutions satisfied all three criteria. Of those tested, Gey salt solution and bovine serum albumin (0.01%) and proteose peptone (1%) in saline were the only two in which the gonococci retained viability in dilute suspensions for 25 min. Most of the solutions were not able to maintain viability of gonococci in dilute suspensions, even when the same solution was capable of maintaining stability and viability in concentrated suspensions

A dominant sulfhydryl-containing protein in the outer membrane of Neisseria gonorrhoeae.

By using a method that labels sulfhydryl-containing proteins in situ, we have detected a major outer membrane protein of Neisseria gonorrhoeae at 41 kDa. A protein of this molecular mass has not previously been shown to be a major outer membrane protein in gonococci. In addition, a minor protein rich in cysteinyl residues was detected at 31.5 kDa