What is a diplomatic emissary of the highest rank called?

A dialyzer is an artificial version of which organ? Which name belongs to both a Dick Tracy villain and a type of crew cut? Complete the title of the Charles Dickens novel: "___ and Son". Which dictator was known as "Il Duce"? Which word names both a diplomatic official and a type of briefcase? A dipsomaniac has an uncontrollable craving for what? What is a disappointing end after a big buildup called? A disastrous economic program called the Great Leap Forward began in which country in 1958?