Pre-exposure prophylaxis (PrEP) is a course of HIV drugs taken daily by HIV negative people most at risk of HIV to reduce their risk of HIV infection. Truvada is currently the only drug approved for use as PrEP. Truvada is a single pill that is a combination of two anti-HIV drugs, tenofovir and emtricitabine.
Astronomical spectroscopy is one of the most powerful tools used by astronomers to gain a fundamental understanding of our universe. Astronomical spectroscopy is a technique in which the absorption and emission of electromagnetic radiation from stars and other celestial objects are studied.he absorption and or emission spectra of a molecule generally consist of a number of lines. These lines correspond to the discrete differences in the internal energy modes of a molecule.
Absorption spectroscopy is employed as an analytical chemistry tool to determine the presence of a particular substance in a sample and, in many cases, to quantify the amount of the substance present.n example of applying Absorption spectroscopy is the first direct detection and chemical analysis of the atmosphere of a planet outside our solar system in 2001. Sodium filters the alien star light of HD 209458 as the hot Jupiter planet passes in front. The process and absorption spectrum are illustrated above.