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
Experimental musical instrument of the usual two (counting the nut as a bridge). By adding a third bridge, one can create a number of unusual sounds reminiscent of chimes, bells or harps A 'third bridge instrument' can be a "prepared guitar" modified with an object – for instance, a screwdriver – placed under the strings to act as a makeshift bridge, or it can be a custom made instrument. One of the first guitarists who began building instruments with an extra bridge was Fred Frith. Guitarist and composer Glenn Branca has created similar instruments which he calls harmonic guitars or mallet guitars. Since