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Chitin (C 8 H 13 O 5 N) n (/ ˈ k aɪ t ɪ n / KY-tin) is a long-chain polymer of N-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chitin are produced each year in the biosphere. [1]
Arthropod cuticle is a biological composite material, consisting of two main portions: fibrous chains of alpha-chitin within a matrix of silk-like and globular proteins, of which the best-known is the rubbery protein called resilin. The relative abundance of these two main components varies from approximately 50/50 to 80/20 chitin protein, with ...
Each of the two auricles collects blood from the gills on one side, while the muscular ventricle pumps blood through the aorta and round the body. The excretory system consists of two nephridia , which connect to the pericardial cavity around the heart, and remove excreta through a pore that opens near the rear of the mantle cavity.
A number of studies have measured the bioavailability of glucosamine after oral administration to horses. When given as a single oral dose (9 g) with or without chondroitin sulfate (3 g) to ten horses, glucosamine (hydrochloride) was detected in the blood with a maximum level of 10.6 ± 6.9 μg/mL at two hours after dosing. [47]
Like cellulose, chitin is an abundant biopolymer that is relatively resistant to degradation. [17] Many mammals can digest chitin and the specific chitinase levels in vertebrate species are adapted to their feeding behaviours. [18] Certain fish are able to digest chitin. [19] Chitinases have been isolated from the stomachs of mammals, including ...
A variety of treatments exist, most notably including the phosphodiesterase type 5 inhibitor drugs (such as sildenafil citrate, marketed as Viagra), which work by vasodilation. Priapism, a form of persistent genital arousal disorder, is a painful and potentially harmful medical condition in which the erect penis does not return to its flaccid ...
Mayo Clinic is a nonprofit hospital system with campuses in Rochester, Minnesota; Scottsdale and Phoenix, Arizona; and Jacksonville, Florida. [22] [23] Mayo Clinic employs 76,000 people, including more than 7,300 physicians and clinical residents and over 66,000 allied health staff, as of 2022. [5]
Chitosan is produced commercially by deacetylation of chitin, which is the structural element in the exoskeleton of crustaceans (such as crabs and shrimp) and cell walls of fungi. [3] [4] [5] A common method for