Interactions synergistic

Figure 9.1 Stress-corrosion cracks result from the synergistic interaction of tensile stress and a specific corrodent.

An active matrix provides the primary cracking sites. The acid sites located in the catalyst matrix are not as selective as the zeolite sites, but are able to crack larger molecules that are hindered from entering the small zeolite pores. The active matrix precracks heavy feed molecules for further cracking at the internal zeolite sites. The result is a synergistic interaction between matrix and zeolite, in which the activity attained by their combined effects can be greater than the sum of their individual effects [2J. 

The four mechanisms discussed above, of the action of inhibitors remain essentially unchanged. Further work on acetylenic alcohols has indicated that barrier films can form owing to crosslinking by hydrogen bonding and synergistic interactions . Theoretical treatments of the electrochemical... 

The proplnts described above are in the realm of prior art and depict those NC proplnts with low smoke potential that are used primarily as gun proplnts. Recent research and development work has been concentrated on creating both gun proplnts and rocket proplnts with reduced smoke output in order to foil countermeasures. Lavitt (Ref 76) found that the concurrent use of optimum proportions of lead stearate and sodium barbiturate in double-base proplnts resulted in a marked reduction in smoke output. This was attributed to the synergistic interaction of the two salts to produce more complete oxidation of the exhaust products. The importance of using the optimum ratio of the two catalysts is demonstrated by the higher smoke values shown in Table 4 for Propellants 105, 106 and 107, when compared to other... 

A final, important distinction between sibutramine and (7-fenfluramine is that the actions of the former, but not the latter, rest on its modification of both 5-HT and noradrenergic transmission. Thus, the reduction in food intake by sibutramine is partially blocked by ai- or jSi-adrenoceptor antagonists as well as 5-HT2a/2C or 5-HT2b/2c antagonists. In fact, there appears to be a synergistic interaction between these two transmitter systems. This is illustrated by a study of the effects of the selective serotonin... 

In some cases, catechins can also act in synergistic mode when used in association with currently used antibiotic molecules (Table 2). EGCG exhibited synergy with /3-lactams. Sudano Roccaro et al. [73] found that this compound is able to reverse tetracycline resistance in Staphylococcus epidermidis and S. aureus isolates. This synergistic interaction has been explained by inhibition of tetracycline efflux pump activity in microbial cells resulting in an... 

Kalyanaraman, B., Darley-Usmar, V.M., Wood, J., Joseph, J. and Parathasarathy, S. (1992). Synergistic interaction between the probucol phenoxyl radical and ascorbic acid in inhibiting the oxidation of LDL. J. Biol. Chem. 267, 6789—6795. 

The larger is the value of Sy, the stronger is the mutual synergistic interaction between the coarse and fine particles. Also, an effective fine particle additive to improve the fluidizing characteristics of coarse particles calls for a large value of m produced with minimal amount of the fine material, that is, a small value of x2. 

Ruden S, Hilpert K, Berditsch M, Wadhwani P, Ulrich AS (2009) Synergistic interaction between silver nanoparticles and membrane-permeabilizing antimicrobial peptides. Antimicrob Agents Chemother 53 3538-3540... 

Synergistic Interaction of Antioxidants, Free Radical Scavengers, and Chelators... 

This mechanism is now considered to be of importance for the protection of LDL against oxidation stress, Chapter 25.) The antioxidant effect of ubiquinones on lipid peroxidation was first shown in 1980 [237]. In 1987 Solaini et al. [238] showed that the depletion of beef heart mitochondria from ubiquinone enhanced the iron adriamycin-initiated lipid peroxidation whereas the reincorporation of ubiquinone in mitochondria depressed lipid peroxidation. It was concluded that ubiquinone is able to protect mitochondria against the prooxidant effect of adriamycin. Inhibition of in vitro and in vivo liposomal, microsomal, and mitochondrial lipid peroxidation has also been shown in studies by Beyer [239] and Frei et al. [240]. Later on, it was suggested that ubihydroquinones inhibit lipid peroxidation only in cooperation with vitamin E [241]. However, simultaneous presence of ubihydroquinone and vitamin E apparently is not always necessary [242], although the synergistic interaction of these antioxidants may take place (see below). It has been shown that the enzymatic reduction of ubiquinones to ubihydroquinones is catalyzed by NADH-dependent plasma membrane reductase and NADPH-dependent cytosolic ubiquinone reductase [243,244]. 

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