Fibres elastic

One partieular form of thermoplastic polyurethane elastomers is the elastic fibre known as spandex fibre. Like the usual thermoplastic rubbers these materials consist of hard and soft segments but to qualify for the term spandex by the US Federal Trade Commission the polymer used should contain at least 85% of segmented polyurethane. The first commercial material of this type was introduced by Du Pont in 1958 (Lycra). Several other similar materials have since been introduced including Dorlastan (Bayer), Spanzelle (Courtaulds) and Vyrene (US Rubber). 

Spandex fibres, because of their higher modulus, tensile strength and resistance to oxidation, as well as their ability to be produced at finer deniers, have made severe inroads into the natural rubber latex thread market. They have also enabled lighter weight garments to be produced. Staple fibre blends with non-elastic fibres have also been introduced. 

Smooth muscle, elastic fibres, collagen (medial layer)... 

Figure 5.2 Cross section through bLood vessels (a) an artery. Sizes of arteries vary from 25 mm diameter with 2 mm wall thickness in the aorta to 20 pm diameter with a 15 pm wall thickness in the smallest arterioles, (b) a vein. Note there are no elastic lamellae in veins so tension is maintained by elastic fibres which are arranged within the media. Typically, veins are approximately 5 mm in diameter but with a very thin wall, for example 0.5 mm. The vena cava is the largest vein at 30 mm diameter...

The tracheo-bronchial epithelium forms the interface between the conducting airways and inspired air. As described above, the epithelium is layered upon a connective tissue substratum consisting of a basement membrane, lamina propria, and submucosa [6], The submucosa contains elastic fibres, a muscularis mucosa, connective tissues and seromucous glands. Lymphatics are also located in the bronchial walls [2],... 

Fibres of protein, including the inextensible collagen and the extensible elastic fibres. 

For nearly half a century the elastic fibre has been considered a primary site of vascular calcification326, 334 336), Calcium deposits in the arterial wall commonly take the form of phosphate salts which are intimately intermeshed with the protein of the elastic fibre327. Much effort has been directed toward identifying the mechanism for the initiation of focal calcification. It has been proposed that the initial step is ionic calcium binding to the uncharged peptide carbonyl oxygens of the elastic fibre protein328, 329. ... 

One of the major development from block copolymer research has been the preparation of elastic fibres. These are characterized by a very high elongation at break, large E-moduli and essentially complete recovery from large deformations 1. ... 

Baccarani-Contri, M., Vincenzi, D., Cicchetti, F., Mori, G., and Pasquali-Ronchetti, I. (1990). Immunocytochemical localization of proteoglycans within normal elastic fibres. Eur. J. Cell Biol. 53, 305—312. 

Yanagisawa, H., Davis, E. C., Starcher, B. C., Ouchi, T., Yanagisawa, M., Richardson, J. A., and Olsen, E. N. (2002). Fibulin-5 is an elastin-binding protein essential for elastic fibre development in vivo. Nature 415, 168-171. 

Aortic samples, free of atherosclerotic lesions, were obtained from haemodialysis patients with end-stage renal disease and from age-matched controls.437 The media, but not the intima, proved positive immunohistochemically for pentosidine, which was observed along and between elastic fibres. In both groups, pentosidine-linked fluorescence was higher in elastin than in collagen, and the HPLC level of pentosidine was higher in the elastin from patients than in that from the controls. 

The lamina propria constitutes a continuous sheet of connective tissue containing collagen, elastic fibres and cellular components in a hydrated ground substance. It also carries blood capillaries and nerve fibres that serve the mucosa. It is through the blood vessels in the lamina propria that drag moieties can gain entry to the systemic circulation. 

The dermis is made up of collagen and elastic fibres overlying connective tissue. A number of important structures are located here. 

Q5 When air enters the pleural cavity, either from the outside when the chest wall is punctured or from the lung itself if alveoli rupture, the visceral and parietal pleura become separated. The consequence of the introduction of air between the pleura is that the lung does not adhere to the pleura and thoracic wall when thoracic volume increases. Instead, the elastic fibres of the lung tissue and the surface tension of the air-water interface in the alveoli cause lung tissue to recoil and eventually collapse. To reinflate a collapsed lung the hole in the chest wall must be closed, a small tube placed in the pleural cavity and suction applied to remove the air from the cavity. 

Description of the lattice fibres and their demarcation by elastic fibre and collagenous connective tissue by A. Oppel. 

Scleral icterus occurs from a serum bilirubin level of 1.6-1.8 mg/dl upwards. At the same time, the conjunctiva is icterially discoloured. Jaundice is based on the affinity of the elastic fibres for bilirubin. 

Dalziel KL, Burge SM, Frith PA, Ryan TJ, Mowat A. Elastic fibre damage induced by low-dose D-penicillamine. Br J Dermatol 1990 123(3) 305-12. 

Figure 9.17 Routes of parenteral medication, showing the tissues penetrated by intramuscular, intravenous, subcutaneous and intradermal injections the needles, with bevel up, penetrate the epidermis (cuticle) consisting of stratified epithelium with an outer horny layer, the corium (dermis or true skin) consisting of tough connective tissue, elastic fibres, lymphatic and blood vessels, and nerves, the subcutaneous tissue tela subcutanea) consisting of loose connective tissue containing blood and lymphatic vessels, nerves, and fat-forming cells, the fascia (a thin sheet of fibrous connective tissue), and the veins, arteries and muscle.

Elastic fibres can be easily recognized by their great extensibility and elasticity as well as their longitudinal microscopic view (often quasi-monofil from coalesced single fibrils). As opposed to rare rubber threads, elastane fibres based on polyurethane dissolve in boiling dimethylformamide and swell markedly in 85% formic acid. 

Hysteresis curves the elastic properties are determined by repeated extension and recovery at a constant rate between fixed limits (hysteresis behaviour, for example according to DIN 53835, five cycles to 300% extension). In the literature--- extensive work on the dynamometric properties of elastic fibres and rabber threads has been cited. From their experience with many complaints... 

Hair follicles, sebaceous glands and sweat glands are part of the epidermis, but they penetrate into the dermis. The dermis consists of loose connective tissue containing fibroblasts that produce collagen and elastic fibres. The dermis also contains lymphocytes, mast cells and macrophages, which respond to injury, infection, allergens and harmful chemicals by releasing inflammatory substances. 

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