Upregulation of glial cell line-derived neurotrophic factor (GDNF) in the rat cochlea following noise. Pharmacologic manipulation of the labyrinth with novel and traditional agents delivered to the inner ear.
Slavery in the United States was the legal institution of human chattel slavery that existed in the United States of America in the 18th and 19th centuries after it gained independence and before the end of the American Civil War.he United States was polarized over the issue of slavery, represented by the slave and free states divided by the MasonâDixon line, which separated free Pennsylvania from slave Maryland and Delaware.
Teach US History. Slavery was the most important and divisive issue in 19th-century American politics and society. At the end of the Revolution, the new American nation was divided between the southern states whose economies were heavily dependent on slavery and northern states where slavery was legal but not economically important.