Barbie been sold with a wide range of titles including "Miss Astronaut Barbie" (1965), "Doctor Barbie" (1988), and "Nascar Barbie" (1998). Mattel has created a range of companions for Barbie, including Hispanic Teresa, Midge, African American Christie, and Steven (Christie's boyfriend). Barbie's siblings and cousins were also created including Skipper, Todd and Stacie (twin brother and sister), Kelly, Krissy, and Francie. Barbie was friendly with Blaine, an Australian surfer, during her split with Ken in 2004. Body Image From the start, some have complained that "the blonde, plastic doll conveyed an unrealistic body image to girls." Criticisms of Barbie are often
S-tag S-tag S-tag is the name of an oligopeptide derived from pancreatic ribonuclease A (RNase A). If RNase A is digested with subtilisin, a single peptide bond is cleaved, but the resulting two products remain weakly bound to each other and the protein, called ribonuclease S, remains active although each of the two products alone shows no enzymatic activity. The N-terminus of the original RNase A, also called S-peptide, consists of 20 amino acid residues, of which only the first 15 are required for ribonuclease activity. This 15 amino acids long peptide is called S15 or S-tag. The amino acid sequence