Natural fiber Keratin is a structural protein located at the hard surfaces in many vertebrates. Keratin has two forms, α-keratin and β-keratin and are used by different classes of animals. The naming convention for proteins follows that for keratin, alpha keratin is helical and beta keratin is sheet like. Alpha keratin is found in mammalian hair, skin, nails, horn and quills, while beta keratin can be found in avian and reptilian species in scales, feathers, and beaks. The two different structures of keratin have dissimilar mechanical properties, as seen in their dissimilar applications. The relative alignment of the keratin fibrils has a
Hair removal been used in attempts to eradicate lice or to minimize body odor due to accumulation of odor-causing micro-organisms in hair. Some people with trichiasis find it medically necessary to remove ingrown eyelashes. Shaving against the grain can often cause ingrown hairs. Many forms of cancer require chemotherapy, which often causes severe and irregular hair loss. For this reason, it is common for cancer patients to shave their heads even before starting chemotherapy. In extreme situations people may need to remove all body hair to prevent or combat infestation by lice, fleas and other parasites. Such a practice was used, for