Tuesdayâs debate between the Democratic presidential candidates, including Hillary Clinton and Bernie Sanders, will be streamed online for free. CNN, which is hosting the debate, will have it available on CNN.com and on the networkâs mobile apps. Coverage begins at 8:30 p.m.
Paraphenylenediamine (PPD) is a chemical substance that is widely used as a permanent hair dye. It may also been found in textile or fur dyes, dark coloured cosmetics, temporary tattoos, photographic developer and lithography plates, photocopying and printing inks, black rubber, oils, greases and gasoline.
The tuberculosis skin test is also known as the tuberculin test or PPD (purified protein derivative) test. The tuberculin skin test is based on the fact that infection with M. tuberculosis bacterium produces a delayed-type hypersensitivity skin reaction to certain components of the bacterium.