Thioglycolic acid corresponding disulfide (2-[(carboxymethyl)disulfanyl]acetic acid or dithiodiglycolic acid): Thioglycolic acid, usually as its dianion, forms complexes with metal ions. Such complexes have been used for the detection of iron, molybdenum, silver, and tin. Thioglycolic acid reacts with diethyl acetylmalonate to form acetylmercaptoacetic acid and diethyl malonate, the reducing agent in conversion of Fe(III) to Fe(II). Scientist David R. Goddard, in the early 1930s, identified TGA as a useful reagent for reducing the disulfide bonds in proteins, including keratin (hair protein), while studying why protease enzymes could not easily digest hair, nails, feathers, and such. He realized that while the disulfide bonds,
Artificial nails overlay acts as a false layer of nail, protecting the nail plate from splitting or becoming damaged. Typically, these methods require the assistance of a trained professional. Cheaper, less rigid tips that can be quickly glued at home are an option to those unwilling to enlist one. Another inexpensive option are stick-on nails, the durability of which ranges from one day to two weeks. Historically, artificial nails were common symbols of status all across the world: "The earliest experiments and resultant artificial nails used a monomer and polymer mix applied to the nail and extended over a supporting form. This