Synergism number

Mutual synergism of binary mixtures containing fine particles can be quantified in terms of the departure of the 0-x2 curve from a linear tie line, which signifies absence of synergism, joining 7 and 2 for the respective components, as shown in Fig. 54. A convenient measure of this departure is the shaded area lying between the -x2-curve and the linear tie line. This can be derived analytically in terms of what will be called the Synergism number Sy, normalized with respect to 07+0, of both the coarse and the fine particles ... 

Sc = u PfDj, Schmidt number, dimensionless Sh = hDdp/Df, Sherwood number, dimensionless Sy Synergism number, dimensionless... 

SCE increases absolute colony number and surviving fraction of CEU-E, CEU-G, and CEU-GM in kradiated human BM. An increase in the fraction of CDSd cells in the radioresistant S-phase has been noted, which suggests a possible mechanism (184). A cautionary note has been sounded about attempting to predict interactions between SCE and CSEs in hemopoieticaHy deprived individuals (185). Although SCE synergizes with GM-CSE or GM-CSE and lL-3 to increase CEU-GM in vitro, no such effect has been found in vivo. 

Very interesting behavior of incorporating anions can be observed when a multicomponent electrolyte is used for oxide formation. Here, anion antagonism or synergism can be observed, depending on the types of anions used. The antagonism of hydroxyl ions and acid anions has been observed in a number of cases. Konno et a/.181 have observed, in experiments on anodic alumina deterioration and hydration, that small amounts of phosphates and chromates inhibit oxide hydration by forming monolayer or two-layer films of adsorbed anions at the oxide surface. Abd-Rabbo et al.162 have observed preferential incorporation of phosphate anions from a mixture of phosphates and chromates. 

A number of studies of the toxicity of zinc oxide/hexachloroethane smoke have been conducted (Brown et al. 1990 Karlsson et al. 1986 Marrs et al. 1983). These studies demonstrate that smoke exposure results in pulmonary inflammation and irritation. When male Porton Wistar rats were exposed to hexachloroethane/zinc oxide smoke for 60 minutes, the lungs showed pulmonary edema, alveolitis, and areas of macrophage infiltration 3 days later. At 14 days, there was interstitial fibrosis and macrophage infiltration. At 28 days, increased fibrosis and macrophage infiltration were noted. However, these same symptoms occurred when the animals inhaled zinc chloride there was no apparent synergism between the zinc chloride and residual hexachloroethane (Brown et al. 1990 Richard et al. 1989). This is consistent with the fact that smoke contains little hexachloroethane and the observation that acute exposure to 260 ppm hexachloroethane had no effects on the lungs of rats (Weeks et al. 1979). 

This scheme of steps reflects the ability of some metals, like the trivalent actinides and lanthanides, to vary their coordination number since the trivalent Ln and An may go from 9 to 8 and, finally, back to 9. The last step reflects the operation of the third mechanism proposed for synergism. 

Synergism between the enzymes was shown to decrease with time during zymolysis. This may occur because the substrate for a particular glu-canase disappeared (but as the substrates were in excess in this case it is unlikely), or the products released during hydrolysis inhibited one or a number of the glucanases. 

During the past few years, the determination of the interfacial properties of binary mixtures of surfactants has been an area in which there has been considerable activity on the part of a number of investigators, both in industry and in academia. The Interest in this area stems from the fact that mixtures of two different types of surfactants often have interfacial properties that are better than those of the individual surfactants by themselves. For example, mixtures of two different surface-active components sometimes reduce the interfacial tension at the hydrocarbon/water interface to values far lower than that obtained with the individual surfactants, and certain mixtures of surfactants are better foaming agents than the individual components. For the purpose of this discussion we define synergism as existing in a system when a given property of the mixture can reach a more desirable value than that attainable by either surface-active component of the mixture by itself. 

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