Mechanisms of priming

Besides the addition of halogens and hydrohalogens across the double bond just covered, there are many other reagents that will react similarly with unsaturated polymers by free radical, ionic, or radical-ion mechanisms. Of prime importance is the addition of ethylene derivatives to polydienes. One of the earliest reactions of natural rubber to be studied in detail was the combination with maleic anhydride (Cunneen and Porter, 1965). Depending on the reaction conditions and the presence or absence of free radical initiators, one or more of four basic reactions may take place, with the products shown (the arrows indicate where the addition has taken place and the new bonds formed). 

It thus appears that hyaluronic acid is synthesised by the alternate addition of acyl-amino-sugar and uronic acid residues at the reducing terminal of the chain and that the last sugar nucleotide added retains its UDP residue. No special mechanism of priming is needed and the hyaluronic acid chain grows... 

Refrigera.tion in Transportation. Styling is unimportant. The volume of insulation and a low thermal conductivity are of primary concern. Volume is not large, so appHcation methods are not of prime importance. Low moisture sensitivity and permanence are necessary. The mechanical properties of the insulant are quite important owing to the continued abuse the vehicle undergoes. Cost is of less concern here than in other appHcations. 

Penney discusses contemporary methods of addressing dissolved gases and makes recommendations of his own with plant examples. Basically his recommendations are as follows. When mechanical damage is of prime... 

Jones, F.R., Interfacial aspects of glass fibre reinforced plastics. In Jones, F.R. (Ed.), Interfacial Phenomena in Composite Materials. Butterworths, London, 1989, pp. 25-32. Chaudhury, M.K., Gentle, T.M. and Plueddemann, E., Adhesion mechanism of poly(vinyl chloride) to silane primed metal surfaces. J. Adhes. Sci. Technol, 1(1), 29-38 (1987). Gellman, A.J., Naasz, B.M., Schmidt, R.G., Chaudhury, M.K, and Gentle, T.M., Secondary neutral mass spectrometry studies of germanium-silane coupling agent-polymer interphases. J. Adhes. Sci. Technol., 4(7), 597-601 (1990). 

The two prime mechanisms of carbon transport within the ocean are downward biogenic detrital rain from the photic zone to the deeper oceans and advection by ocean currents of dissolved carbon species. The detrital rain creates inhomogeneities of nutrients illustrated by the characteristic alkalinity profiles (Fig. 11-9). The amount of carbon leaving the photic zone as sinking particles should not be interpreted as the net primary production of the surface oceans since most of the organic carbon is recycled... 

Rohsenow s early correlation Using the form of correlation shown in Eq. (2-78), and assuming that the convection mechanism associated with bubble liftoff is of prime importance, Rohsenow (1952) found empirically, with data obtained from a 0.024-in. (0.6-mm) platinum wire in degassed distilled water, that... 

The mechanism of skeletal muscle contraction is described by the Sliding Filament Theory (see Figure 11.2). This mechanism begins with the "priming ... 

Conversely, the cross-correlation rates depend solely on the csa mechanism and on the dipolar interaction which is of prime importance here. It arises in fact from correlation functions of the form b (t)b(0), where b (t) refers to the csa mechanism whereas b(t) refers to the dipolar interaction. One has... 

Treatment of RA patients with various drugs was shown to affect free radical production by phagocytic cells. It was found that the therapy with gold compounds [252] and piroxicam [237] diminished superoxide production in RA patients. Surprisingly, Hurst et al. [253] reported that successful therapy with penicillamine or sodium aurothiomalate is accompanied by an increase in superoxide production and serum thiol levels. The mechanism of this phenomenon is unknown. Mur et al. [254] demonstrated that antirheumatic medication of RA patients caused reducing cytokine priming of superoxide generation. 

Docke F, Rohde W, Sturzebecher B, Ledwon P, Dorner G (1990) Evidence that desensitization of the negative feedback of oestrogen and priming for the positive feedback of oestrogen depend upon a common mechanism of oestrogen action in rats. J Endocrinol 126 395-402... 

As the above illustration shows, calculations using classical theories, especially electrostatics, are relatively easy to picture. However, matter at an atomic scale is best described by quantum mechanics. Quantum theory calculations are more difficult and are preferred when electronic properties are of prime importance. Both techniques are described in the following sections. 

---