Comparative evaluation of in-house manual, and commercial semi-automated and automated DNA extraction platforms in the sample preparation of human stool specimens for a Salmonella enterica 5'-nuclease assay.

In the present study, three methods (NucliSens miniMAG [bioMérieux], MagNA Pure DNA Isolation Kit III Bacteria/Fungi [Roche], and a silica-guanidiniumthiocyanate {Si-GuSCN-F} procedure for extracting DNA from stool specimens were compared with regard to analytical performance (relative DNA recovery and down stream real-time PCR amplification of Salmonella enterica DNA), stability of the extracted DNA, hands-on time (HOT), total processing time (TPT), and costs. The Si-GuSCN-F procedure showed the highest analytical performance (relative recovery of 99%, S. enterica real-time PCR sensitivity of 91%) at the lowest associated costs per extraction (euro 4.

Use of carbon dioxide laser in improving knot security in polyester sutures.

Knot slippage continues to be a serious concern in surgery. This study explored the possibility of improving knot performance by exposing it to radiation from a CO 2 laser. The specimens were mounted in a special device and exposed in a predetermined position for precisely controlled lengths of time.

Monitoring particulate carbon collected on Teflon filters: an evaluation of photoacoustic and transmission techniques.

The Colorado State University Aerosol Workshop provided an excellent opportunity to obtain various particulate samples collected on filters. Our results indicate that the photoacoustic technique is preferable to the transmission technique (integrating plate method) for ambient samples with low-filter loadings since the presence of a nonabsorbing scattering aerosol (ammonium sulfate) only slightly perturbs the photoacoustic signal and significantly affects the transmitted signal. Measurements indicate that the photoacoustic signal depends not only on the energy absorbed from the incident beam but also on the existence of thermal wave interference effects and, especially for heavily loaded filters, on the presence of a nonabsorbing scattering aerosol.

Thermal wave interferometry: a potential application of the photoacoustic effect.

The Rosencwaig-Gersho equation for the photoacoustic signal is recast in a manner that emphasizes the crucial role thermal wave interference plays in the production of the photoacoustic signal. This formalism is then used to suggest a technique for extracting thermal information from the structure in the photoacoustic signal resulting from thermal wave interference. Experimental measurements illustrating this technique are presented.

Investigation of genetic factors influencing duration of copulation in "eastern" and "western" Drosophila athabasca.

Observations of mating behaviour were made on "eastern" and "western" Drosophila athabasca and on flies of mixed genetic background. Duration of copulation in mixed combinations of D. athabasca is determined by the male.

CO(2) Laser Absorption Coefficients for Determining Ambient Levels of O(3), NH(3), and C(2)H(4).

A carbon dioxide laser source was used to determine absorption coefficients for dilute absorber-air mixtures at wavelengths corresponding to several vibration-rotation lines in each branch of the 00 degrees 1-02 degrees 0 band at 9.4 microm and the 00 degrees 1-10 degrees 0 band at 10.4 microm.

Photometer for detection of sodium day airglow.

Daytime, ground based measurements of sodium airglow emission are particularly difficult to perform. The ratio of airglow signal to Rayleigh and Mie scattering by the atmosphere as well as the very pronounced Fraunhofer structure lead to extraneous signals that are difficult to evaluate and require specialized techniques to eliminate. The photometer described can be characterized by the following principal features: (1) a narrow (4.

Determination of Self-Broadening Coefficients of CO, Using CO(2) Laser Radiation at 10.6 micro.

Essentially monochromatic radiation with a frequency corresponding to the frequency of the line center of the P(20) line of the 961-cm(-1) CO(2) band was obtained from a CO(2)laser. Using this radiant energy, transmittances of CO(2) samples were measured as various broadening gases were added. Self-broadening coefficients of CO(2) relative to nitrogen, hydrogen, helium, and argon were determined from the measurements characterizing the transmittance only at the line center; from these measurements ratios of optical collision diameters are calculated.