Shark skin

In dermatan sulfate from shark skin, there is about a 40% excess of sulfate groups over 2-acetamido-2-deoxy-D-galactose residues.300 The small proportions of D-glucu-ronic acid (d-GUA) present in dermatan sulfate occur in regions of the carbohydrate chains both near to, and far from, the carbohydrate-peptide linkage region. The isolation of the tetrasaccharide... 

Nomura, Y., Yamano, M., and Shirai, K. (1995). Renaturation of alpha 1 chains from shark skin collagen type I. ]. Food Sci. 60,1233-1236. 

S S Shark Skin filter paper has high wet-strength and a high resistance to acids and alkalies. 

Set up a 2-liter separatory funnel on a ring stand as shown in Figure G 1.1.1. Use a liquid funnel to help direct the liquids into the separatory funnel, and a powder funnel with shark skin-fluted filter paper containing 50 g anhydrous magnesium sulfate on a 1-liter receiver flask. 

Bechert DW, Bruse M, Hage W (2000) Experiments with three-dimensional riblets as an idealized model of shark skin. Exp Fluids 28 403—412... 

Wainwright SA, Vosburgh F, Hebrank JH (1978) Shark skin - function in locomotion. Science... 

Filter paper, hardened, 22, 45 Shark skin, 25, 97 Fischer indole synthesis, 22, 98 Flash distillation, 21, 85 Flask, modified Claisen, 22,11 Fluorescence of 9-aminoacridine hydrochloride, 22, 7... 

A good example to explain this impetus is the shark skin effect. The scales of predatory fishes have fine longitudinal grooves that cause less cross-flow in the displaced water. This principle has been adapted to aeroplane surfaces to help to reduce fuel consumption by 1 %. Similar shark skin swimsuit surfaces allow competitive swimmers to enjoy the advantages of lower resistance to movement through the water. 

The extent to which die-wall slip is involved can be assessed by using dies of different lengths and diameters. An important characteristic that can be observed in the extrudate is its quality in terms of surface structure. Harrison, Newton, and Rowe, have shown how this can vary from a smooth, regular surface via a rough, shark-skinned extrudate. There is obvious need to prevent this phenomenon if extrudate of the correct quality is to be produced. The occurrence of the surface defects is associated with both the composition of the material and the operating conditions (e.g., die length and diameter and the rate of... 

Sodium hyaluronate occurs naturally in vitreous humor, serum, chicken combs, shark skin, and whale cartilage it is usually extracted and purified from chicken combs. It may also be manufactured by fermentation of selected Streptococcus zooepidemicus bacterial strains sodium hyaluronate is removed from the fermentation medium by filtration and purified by ultrafiltration. It is then precipitated with an organic solvent and dried. 

As has been described above, HA is an essential functional component of almost all tissues in the vertebrate organism. Thus, various animal tissues - e.g. rooster combs, shark skin, bovine eyeballs - have been used as sources of isolation and production of high molar mass HAs. Since in the biological materials HA is usually present in a complex linked to other biopolymers, several separation procedures have to be applied in order to obtain a pure compound, such as protease digestion, HA ion-pair precipitation (with e.g. cetylpyridinium chloride), membrane ultrafiltration, HA non-solvent precipitation and/or lyophilization [135,136]. The mean molar mass of the commercially available extractive HA preparations obtained from animal tissues is mostly in the range from several hundred thousands Da up to approximately 2.5 MDa. To date, the demand for HA materials approved for applications in human medicine has been satisfied by high molar mass HAs prepared from the rooster combs. For example, Healon (Pharmacia Upjohn, Inc., Peapack, NJ, USA) - used in viscosurgery at eye implant insertion - has a mean HA molar mass of about 2.5 MDa. 

The formation of defects and phase separation is an important consideration in paste extrusion. Typical defects include lamination or delamination (occurring with joining of adjacent past streams) and surface fracture, often referred to as shark-skin formation. Surface fracture generally increases with decreasing paste liquid... 

At about 300 sec, the extrudate becomes less smooth and exhibits shark skinning that limits the... 

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