Activity Weight fraction

Table 2 Molecular Weights, Hydrophobization and Limuius Activity of Fractionated poly(MA-CDA)s...

Under all ordinary circumstances the average lengths of terminal chains and of internal chains will be the same, or nearly so hence represents the weight fraction of the structure which is active in deformation. For certain applications, as for example to crystallization induced by stretching, 8a is an appropriate measure of the effective portion of the... 

Tissue Orpan content (fraction of activity) Concentration" (fraction of activity/g wet weight)... 

Figure 5.5 Calculated dependence of weight fractions of various substructures in the crosslinking system of H3 + I2 type on the initial molar ratio of H-groups to l-groups, ah (a polyurethane system) DC - dangling chains, BC - backbone chains, S - sol (backbone chains are elastically active network chains without dangling chains)...

VJhile histamine releasing activity is mainly associated with high molecular weight fractions, they are not necessarily the same ones responsible for antigenic or chemotactic activity, indicating the possibility that several mechanisms may be responsible for bysslnosis. 

Commercial products contain both low and high molecular weight heparin fractions. Low molecular weight heparin has a greater inhibitory effect on factor Xa, and less antithrombin activity than the high molecular weight fraction. 

What explanation can be given for this apparently contradictory result that both yield and molecular weight of crystalline polymer increase with the increase in the amount of catalyst It seems reasonable to assume that the experimental result is due to a cocatalytic action of some substance contaminating the polymerizing system. This substance may activate a fraction of the catalyst by its cocatalytic action and the unactivated catalyst may suppress effectively the termination or chain transfer reaction. If this assumption is correct, some correlations should exist between the amount of catalyst and that of cocatalyst. The most plausible candidate for such a cocatalyst is water and/or oxygen. 

In this case, in fact, the optical activity is mainly connected with the presence in the side chains of an excess of asymmetric carbon atoms having (R) or (S) absolute configuration, the asymmetric terminal groups giving an appreciable contribution to the rotatory power only in low-molecular-weight fractions. 

Fig. 11.20 summarizes experimentally observed trends in the area-normalized activity (black bars) and the Pt weight-fraction-normalized activity (white bars) of some electrocatalysts in Fig. 11.17. It can be seen that a small difference in area-...

Activity normalized by Pt-area and Pt-weight-fraction Activity normalized by Pt-area 3.31... 

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