Tail-biting

Low acute amphetamine doses enhance pain-induced aggressive/defensive reactions in mice, rats, and squirrel monkeys (Kostowski 1966 Hoffmeister and Wuttke 1969 Crowley 1972 Powell et al. 1973 Emley and Hutchinson 1972 Emley and Hutchinson 1983). For example, squirrel monkeys subjected to electric shocks to their tails, bite a rubber hose more frequently after being administered amphetamine (0.06 to 1.0 mg/kg, SC) (Emley and Hutchinson 1972 Emley and Hutchinson 1983 Hutchinson et al. 1977). In rats, these pain-induced aggressive/defensive responses increase with doses of 0.1 to 1.0 mg/kg (Crowley 1972). 

Polymeric sulfur is produced commercially as insoluble sulfur (IS) and is used in the rubber industry [56] for the vulcanization of natural and synthetic rubbers since it avoids the blooming out of sulfur from the rubber mixture as is observed if Ss is used. The polymeric sulfur (trade-name Crys-tex [57]) is produced by quenching hot sulfur vapor in liquid carbon disulfide under pressure, followed by stabilization of the polymer (against spontaneous depolymerization), filtration, and drying in nitrogen gas. Common stabilizers [58] are certain olefins R2C=CH2 like a-methylstyrene which obviously react with the chain-ends (probably -SH) of the sulfur polymer and in this way hinder the formation of rings by a tail-bites-head reaction. In this industrial process the polymer forms from reactive small sulfur molecules present in sulfur vapor [59] which are unstable at ambient temperatures and react to a mixture of Ss and on quenching. 

Formation of EO/THF macrocyclics probably occurs via tail-biting and back-biting mechanisms as outlined in Figure 5. The back-biting reaction route appears most likely for this system. Since no THF homocyclic oligomers have been found in this copolymerization and are extremely limited in THF... 

Figure 5. Mechanism for formation of EO/THF macrocyclics involving both back-biting and tail-biting routes.

In the dark, inefficient active transport (6.6x10 mol h l) was still observable due to intermolecular complexation. However, the rate was enhanced up to 1.4xl0 7 mol h"l by photoirradiation. This significant rate increase can be rationalized in terms of a photoinduced intramolecular "tail-biting" which facilitates a competitive ion ejection into the acidic OUT aqueous phase (Figure 2). It appears, therefore, that the photoinduced "tail-biting" acts as an effective tool when the carrier concentration is lowered enough for the carrier to exist as a discrete monomeric unit. 

Phenolic resins were the first totally synthetic plastics invented. They were commercialized by 1910 [I]. Their history begins before the development of the structural theory of chemistry and even before Kekule had his famous dreams of snakes biting their tails. It commences with Gerhardt s 1853 observations of insoluble resin formation while dehydrating sodium salicylate [2]. These were followed by similar reports on the behavior of salicylic acid derivatives under a variety of reaction conditions by Schroder et al. (1869), Baeyer (1872), Velden (1877), Doebner (1896 and 1898), Speyer (1897) and Baekeland (1909-1912) [3-17]. Many of these early reports appear to involve the formation of phenolic polyesters rather than the phenol-aldehyde resins that we think of today. For... 

A snake biting its own tail seems a far remove from structural theory, but how many scientific advances arise in just such ways ... 

Now I could see it better— tail up, back arched. Cats rarely contract rabies, but they are especially vicious when they do. A bite from a rabid cat must be one of the least pleasant ways of going to one s eternal reward, and I did not tmst my swordsmanship against feline reflexes. 

Shen This talisman depicts a reed tied in a circle to represent the orbit of the sun and, therefore, it became a symbol of the cycle of time and eternity. It was commonly made of lapis lazuli or carnelian and laid on the dead to ensure eternal life. Symbolically, the Shen is related to the symbol of a snake forming a circle by biting its tail, called an ouroboros, which became an important alchemical symbol. 

Pyrrole reacts with aldehydes and ketones and an acid catalyst to form resins, probably linear polymers however, surprisingly, from an entrop-ic point of view, with acetone (propanone) and hydrochloric acid the product is a cyclic tetramer. Possibly the two methyl groups in the developing side chains force it to bend and thus bite its own tail (Scheme 6.7). 

Shock-or pain-induced, mostly in rats, also monkeys Electric shock via grid floor or to tail to pairs of animals Somewhat similar to reaction to predator or large opponent Defensive reactions, including upright posture, bites toward opponent s face and inanimate objects, audible vocalization... 

Another symbol which enters throughout all alchemical literature and graphic representation is the serpent Ouro-boros in the attitude of biting his tail—symbol of the eternal cycle of world changes, as also of the cycle of chemical transformation, distillation, and condensation. This symbol is thus described in the same manuscript as the foregoing upon the egg.84... 

Intrathecal administration of big dynorphin (1-10 fmol) produced a characteristic behavioral response, the biting and/or licking of the hindpaw and the tail along with a slight hindlimb scratching directed toward the flank (Tan-No et al., 2002). 

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