Keratin materials

hooves, and baleen these materials may seem like strange companions, but they are all composed of basically the same material, the protein keratin. Hair and feathers are also keratin, but are addressed in detail in previous sections. All of these materials form on the outside of an animal s body, in the skin. 

The shells of terrestrial tortoises and freshwater turtles have also been used in some of the same ways as the larger marine turtles. Whole turtle bodies, with the soft tissue and most of the skeleton removed, have been made into pouches and specialized containers for personal and ceremonial use. 

The outside of the horn-like casque is often red, while the inside is a creamy yellow. This material was highly sought-after and, before the invention of firearms, very difficult to obtain. Asian artists produced snuff bottles, buttons, netsukes, and other small objects from this material. Sometimes the entire head of the bird would be retained, parts of it carved and some areas left in their natural state, sometimes even with feathers intact. Hornbill ivory is also known as golden jade, crane s crest, crane s bill, and ha-ting. 

Whale hunters were interested in these huge animals for their meat and oil, but also for baleen. In the days before the invention of plastic, baleen was used to make objects that required flexibility and low density. Baleen was also called whalebone, even though it is not made of bone and does not come 

These hair ornament are made of plastic, as imitations of tortoiseshell. 

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Cornified hardened or horny keratinous material like a skin callus, horn, claw, or nail. 

Hair is a keratinous material, quite strong and totally flexible. Long hair was required for fashioning, for example a bracelet needed hair that was at least 60 centimetres long. Before it was worked the hair was boiled. It was then plaited or woven like lace around a mould or firm base, and boiled again to keep the shape. 

The casque is chemically different from ivory, so the name hombill ivory is misleading. It is made of a keratinous material that can be carved, turned, or, being thermoplastic, flattened or moulded. The red surface may be totally or partially removed in working. With time the yellow colour fades to a dark, creamy hue. 

If the orifice of the follicular canal opens sufficiently, the keratinous material extrudes through it and an open comedone results. This is also known as a blackhead, as the keratinous material darkens in contact with the air. Because this material can escape, the comedone does not become inflamed. If the follicular orifice does not open sufficiently, a closed comedone (whitehead) results, within which inflammation can occur. Most acne sufferers have a combination of both. 

Comedo, comedones (pi.)—Plug of sebum and keratinous material in a hair folUcle blackhead. 

U.S. 4,195,077 (1980) Marsh et al. (Procter Gamble) Modified protein Protect keratinous material... 

In other work relating to the protofibrillar concept in keratin filaments, Dobb [138] used ultrasonication techniques to isolate filaments with diameters of 2.0-2.5 nm from chemically treated keratinous materials. In negatively stained TEM preparations, he further observed an axial repeat of 20-nm spacing in the filaments. Filaments with diameters of approximately 2nm were also observed by Rogers and Clark [139] and Johnson and Speakman [140,141] in similar preparations. 

Piezoelectric properties have been found in human hair and other keratinized materials. This is also the case for bone and tendon. Bone remodeling has been attributed to piezoelectricity. The theory is that the mechanical stress on a bone generates bioelectricity that in turn influences bone growth. Because most biomaterials exhibit piezoelectric properties, it is not strange that there are many theories postulating piezoelectric effects in tissue for example, that the transducer mechanism in the inner ear, in the hair follicles, and of touch and vibrational sensitivity is piezoelectric. Results in the literature are often with dry sample, and the question remains as to the importance of piezoelectricity in living, highly conductive tissue. 

Major Applications Display device, i recording materials, inks, paints, " method for preserving food, 5 method for gene expression profiling, treatment of parasitic diseases, neurological diseases, epilepsy, cancer, - keratin materials, neoplasms, " infectious diseases, neutropenia, detecting chromosome aberrations, bacteria in gastrointestinal track ... 

Vic, G. Composition for treating keratin materials comprising at least one electrophilic monomer and at least one salt. U.S. Pat. Appl. Publ. US 2006078522, 2006 Chem. Abstr. 2006,144, 376065. 

Wassenaar, L.I., Hobson, K.A. (2006) Stable-hydrogen isotope heterogeneity in keratinous materials mass spectrometry and migratory wildlife tissue subsampling strategies. Rapid Commun. Mass Spectrom.,20, 2505—2510. 

The properties and physico-chemical characteristics of proteins in an aqueous solvent system depend on the pH conditions. Many protein-based materials are sensitive to pH variations, which could be linked with the relatively high proportion of ionised polar amino acids in protein raw materials (Table 11.7). Zein and keratin materials can, for example, be produced within a broad pH range because these proteins (which have a low ionised polar amino acid content, 10% and 10.7%, respectively), are not very sensitive to pH variations [69]. Conversely, the high content of ionised polar amino acids in soy proteins (25.4%) limits film-forming applications to within a narrow pH range [148]. 

Table 1 Comparison of mechanical properties of keratinized materials and other biological and synthetic materials (modified from [10, 61] with permission.)...

The properties and physicochemical characteristics of proteins in an aqueous solvent system depend on the pH conditions. Many protein-based materials are sensitive to pH variations, which could be linked with the relatively high proportion of ionised polar amino acids in protein raw materials (Table 11.7). Zein and keratin materials can, for... 

PROTECTION OF KERATINOUS MATERIALS WITH SYNTHETIC PYRETHROID INSECTICIDES... 

Over the years, many chemicals have been used as fabric protectants or mothproofers to protect woolens and other keratinous materials against damage by clothes moths or carpet beetles. The substituted phenols, fluoride compounds, sulfonate compounds, and chlorinated hydrocarbon insecticides are some of the chemicals which have been used to protect woolens against insect damage. 

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