Silky

This form melts at 290 K, and boils at 318 K. The P form, obtained when the a form is allowed to stand for a long time at a temperature below 298 K. exists as asbestos-like, silky, felted needles and has a structure consisting ofSO tetrahedra linked together in long chains. 

HCl. The derivative crystallises out immediately filter off, wash with cold water and reciystallise from boiling water. Long colourless silky needles, m.p. 179 . 

Silk degumming Silk Screening Silk-screen inks Silkworm Silky II Polydek Sillemanite Silkmanite Sillimanite [12141-45-6]... 

The fiber stmcture is very fine near the surface of the skin and this fine stmcture imparts a silky feel to the leather. The smaller the animal of a given species the finer the surface fibers. The value of the skin or hide is then dependent in part on this smoothness (2). Calfskin leathers are smoother and have a silkier feel than cattle hide leathers. Calfskin leather is used in the shoe uppers of high quahty, expensive men s and women s shoes, and specialty items. 

Wa.llpa.per and Coated Paper. The shiny particles of mica give a silky or pearly luster when appHed to paper. The effect is pleasing to the eye, and in some cases simulates fabric. 

Detergents and Lotions. The addition of PEO provides a silky feel to soHd and Hquid products. This unique lubricious property has been successfully exploited in formulation of razor strips (169) and in shampoos, detergents, and other personal-care appHcations. Eormulations are available from the manufacturers. 

Crystallization. Acidified aluminum sulfate solutions can be supercooled 10 °C or more below the saturation point. However, once nucleation begins, the crystallization rate is rapid and the supersaturated solution sets up. The onset of nucleation in a gentiy stirred supersaturated solution is marked by the appearance of silky, curling streamers of microscopic nuclei resulting from orientation effects of hydraulic currents on the thin, platelike crystals. Without agitation, nucleation in an acidified solution, in glass tubes, can yield extended crystalline membranes of such thinness to exhibit colors resulting from optical interference. 

Polyethylene terephthalate [25038-59-9] (8) is a polyester produced by the condensation polymerization of dimethyl terephthalate and ethylene glycol. Polyethylene terephthalate sutures are available white (undyed), or dyed green with D C Green No. 6, or blue with D C Blue No. 6. These may be coated with polybutylene adipate (polybutilate), polyydimethylsiloxane, or polytetrafiuoroethylene [9002-84-0]. The sutures are distributed under the trade names Ethibond Exel, Mersdene, Polydek, Silky II Polydek, Surgidac, Tevdek II, Polyester, and Tl.Cron. 

Identification. When a solution of ferric chloride is added to a cold, saturated vanillin solution, a blue color appears that changes to brown upon warming to 20°C for a few minutes. On cooling, a white to off-white precipitate (dehydrodivanillin) of silky needles is formed. Vanillin can also be identified by the white to slightly yellow precipitate formed by the addition of lead acetate to a cold aqueous solution of vanillin. 

Urokinase (from human urine) [9039-53-6] Mr 53,000, [EC 3.4.21.31]. Crystn of this enzyme is induced at pH 5.0 to 5.3 (4") by careful addition of NaCl with gentle stirring until the soln becomes turbid (silky sheen). The NaCl concentration is increased gradually (over several days) until 98% of saturation is achieved whereby the urokinase crystallises as colourless thin brittle plates. It can be similarly recrystd to maximum specific activity [104K CTA units/mg of protein (Sherry et al. J Lab Clin Med 64 145 1964)]. [Lesuk et al. Science 147 880 1965 NMR Bogusky et al. Biochemistry 28 6728 1989.] It is a plasminogen activator [Gold et al. Biochem J 262 1989 ]. 

Xanthotoxin (Methoxalen, 9-methoxyfuro[3,2-g][l]benzopyran-7-one) [298-81-7] M 216.2, m 146-148 , 148 , 148-149 . Purified by recrystn from CgH6-pet ether (b 60-80°) as silky needles, Et0H-Et20 as rhombic prisms or hot H2O as needles. It is soluble in aqueous alkali due to ring opening of a lactone but recyclises upon acidification. It has UV EtOH at 219, 249 and 300nm (log e... 

Corytuberine, C43H21O4N. 5H2O. (Items 18, 31, 37 list, pp. 171-2.) This alkaloid, obtained by Bobbie and Lauder from commercial corydaline, crystallises in silky needles, m.p. 240° dec.), 282-65°... 

B. HCl. H2O, m.p. 242° (dry), [ajo — 117-6° (dry salt, c — 1-214, H2O), forms monoclinic double pyramids, or silky prisms with 2H2O, from its saturated aqueous solution. The dry salt is moderately soluble in water (1 in 38-5 at 10°), or ether (1 in 325 at 10°), readily in chloroform. The acid hydrochloride, B. 2HC1. HjO, forms large monoclinic prisms easily soluble in water or alcohol. The dihydrobromide, B. 2HBr. 2H2O, crystallises well from water and has — 114-3° (dry salt, c = M/40, H2O). The... 

Perlolidine, C25H4j02N4, occurs naturally and is also produced in small yield by the oxidation of perloline in various ways. It crystallises in silky needles, m.p. 325-6°, sublimes at 180°/0-04 mm., and yields a dihydrochloride, B. 2HC1.2H2O, m.p. > 350°. It shows a marked blue fluorescence in neutral or acid aqueous solution, which with the hydrochloride is visible at 0-15 parts per million. The base is phenolic it... 

HeUeborus viridis L. contains ceUiamine, CjjHjjOjN, silky needles, m.p. 127-131°, tertiary base no methoxyl group. SprintiUamine,... 

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