Radioimmunoassay (RIA) is a very sensitive in vitro assay technique used to measure concentrations of antigens (for example, hormone levels in blood) by use of antibodies. As such, it can be seen as the inverse of a radiobinding assay, which quantifies an antibody by use of corresponding antigens. Although the RIA technique is extremely sensitive and extremely specific, requiring specialized equipment, it remains among the least expensive methods to perform such measurements.
Everything American Express is offering during the US Open this year is designed to enhance what tennis fans love about this tournament, said Deborah Curtis, vice president of entertainment and sports marketing at American Express.
US Open Tennis Ticket Information. Historic Grand Slam action is within your reach! US Open tennis tickets are on sale now through fan-favorite ticket marketplace, Vivid Seats. The annual hard court tennis tournament held in New York City is set for another two weeks of world-class tennis this year.egends of the game like Sampras, Agassi, and Federer have all hoisted the trophy in victory on the iconic, blue hard court inside Arthur Ashe Stadium, and with US Open tennis tickets, you can be there live as this yearâs champ etches his name in history in the final Grand Slam of the year.