Biodegradable polymer which, edible films have gained more attention due to their environmentally-friendly characteristics, vast variety and availability, non-toxicity, and low cost. Biodegradable polymers have a long history, and since many are natural products, the precise timeline of their discovery and use cannot be accurately traced. One of the first medicinal uses of a biodegradable polymer was the catgut suture, which dates back to at least 100 AD. The first catgut sutures were made from the intestines of sheep, but modern catgut sutures are made from purified collagen extracted from the small intestines of cattle, sheep, or goats. The concept of synthetic
Piano history and musical performance century, the possibility exists that performers might profitably experiment with what would count as "authentic" pianos, in light of the particular composer's own musical preferences. To this end the pianist Gwendolyn Mok has recently made commercial recordings of Ravel's music on an 1875 Erard piano; see External Links below. Piano history and musical performance The modern form of the piano, which emerged in the late 19th century, is a very different instrument from the pianos for which the classical literature for piano predating this time was originally composed. The modern piano has a heavy metal frame, thick strings made of