Two-dimensional measurement of hydrocarbon fuel concentration using multiple laser-induced plasma-forming regions.

A two-dimensional measurement of fuel distribution in a gasoline spray flow was performed using multiple laser-induced plasma-forming regions. Multiple plasma-forming regions were generated by a laser sheet with a low breakdown threshold for a two-phase flow. To observe the formation of multiple laser-induced plasma-forming regions, shadowgraphs were imaged using a high-speed camera. Hydrogen and oxygen atomic emissions from the plasma-forming regions were obtained by attaching bandpass filters to the high-speed camera, and a two-dimensional visualization of the fuel distribution in the wide plasma-forming region was obtained by dividing the hydrogen line-filtered image with the oxygen line-filtered image. The result complements a novel method for two-dimensional measurement of instantaneous fuel concentration in the reacting flow by utilizing laser-induced breakdown spectroscopy (LIBS).

Assessing PCV2 antibodies in field pigs vaccinated with different porcine circovirus 2 vaccines using two commercial ELISA systems.

Porcine circovirus type 2 (PCV2) is the primary causative agent for post-weaning, multisystemic, wasting syndrome. Consequently, serologic detection of and vaccination against PCV2 are important for the swine industry. Among several serological tests, the enzyme-linked immunosorbent assay (ELISA) is commonly used to measure anti-PCV2 antibody levels. In the present study, we used two commercial ELISA systems to comparatively evaluate anti-PCV2 antibodies in field pigs treated with three different PCV2 vaccines. Among a total of 517 serum samples, the results of the two ELISAs were fully concordant for 365 positive and 42 negative samples, indicating 78.7% agreement. In addition, the Pearson coefficient (0.636) indicated a moderate correlation between data from the two ELISAs. Results from the farms with pigs vaccinated with the three different PCV2 vaccines demonstrated that most of the vaccinated animals underwent seroconversion. However, the increase and duration of antibody titers varied depending on the vaccine, the presence of maternal antibodies, and the vaccination program. PCV2 serologic status and anti-PCV2 antibody levels of herds from this study could be utilized to determine the best timing for vaccination and assessing vaccination compliance.