Promotional phase

Heat treatment of the glasses at 600 °C for 6 hours reduced their reactivity, by promoting phase separation, and prolonged the setting time of cements. Thus, the setting time of the cement formed from one glass (Si Al = 1-7) was increased from 2 0 minutes to 5-3 minutes and that of another glass (Si A1 = 2 0) from 3-6 minutes to 25 minutes. 

To promote phase transfer in the toluene/H20 solvent system, 1 drop of Aliquat 336 (tricaprylmethylammonium chloride, Aldrich) was added. For kinetic studies, aliquots (0.1 ruL) were withdrawn by syringe at timed intervals (20-360 s)... 

The thermal stability of mesoporous frameworks substantially increases with an increase in the wall thickness and pore size, which can be varied even for the same template by changing the processing conditions. Ozin et al.55 developed a way to prepare crystalline titania films with a 2D-hexagonal architecture by replacement of ethanol in the Pluronic-containing precursor solution with more hydrophobic butanol-1. The latter promotes phase separation at low surfactant-to-titania ratios, resulting in thicker pore walls, which are more compatible with the crystal growth during subsequent calcination. 

API. 1989. Short-term dermal tumorigenesis study of selected petroleum hydrocarbons in male CD-I mice. Initiation and promotion phases Final Report API 36-32643. American Petroleum Institute Washington DC. 

The tendency of B to promote phase separation in glass specimens predicts that a wide... 

It can also be observed from the schematic of the interactions shown in Fig. 10 that interaction zones that provide the possibility for sharing sulfur atoms by the two different phases exist. The structure of these interaction zones are crucial to understanding the interaction of sulfides with supports and promoter phases. The basal plane interaction with a second phase can be expected to be weak, but charge transfer might be expected if metal atoms are exposed on the second phase. Such an interaction would be similar to an intercalation interaction. The edge interaction will be much stronger, and here a transition zone with a possible epitaxial relationship between MoS2 and the second phase is expected. It is in this zone that we can expect to find the surface phases as described above (for example, the CoMoS phase). But in the cases described here, the surface phase becomes a line phase at the boundary between the two bulk phases. It is our belief that the detailed study of these phases represents a key area for future research in TMS catalysis. 

VII. Recent Developments in the Description of the Active Promoted Phase... 

Also, selenium-dependent glutathione peroxidase activity has been shown to be reduced in selenium-deficient rats (C. Reddy, ( li). Selenium appears to inhibit both the initiation and promotion phases of carcinogenesis (Milner,... 

The stage of carcinogenesis at which the effect of dietary fat is exerted appears to be during the promotional phase of carcino-... 

Current research in animal models which suggests that the carcinogenic response to a variety of colon carcinogens is enhanced by the dietary fat and inhibited by several dietary fibers, indicates that these nutritional factors may operate during the promotional phase of carcinogenesis. The carcinogenic process in humans may... 

These results implicate BHT as having a role in the activation, initiation or early promotional phase of DMBA-induced chemical carcinogenesis. A definite possibility is that it may require this period of time to allow for the induction of specific metabolic enzymes involved in the handling of DMBA. This time may be required for the attainment of sufficient levels in the tissues to allow effectiveness as an inhibitor. Further studies are certainly needed to narrow the wide range of possibilities. 

As previously mentioned, carcinogenesis is a complex process and it would be naive to believe that dietary protein alters only the initiation phase. A series of eloquent studies by Appleton and Campbell (22, 23, 24) have indicated that the effects exerted by dietary protein during the promotional phase of AFBi hepatocar-cinogenesis are as important, if not more so, than the effects seen during the initiation phase. 

In summary, it has been shown that dietary protein levels can influence the metabolism of the mycotoxin AFBi. Altered metabolism is, in part, responsible for the protective role of low protein diets with respect to carcinogenicity and possibly with its increased toxicity in protein deficient rats. Dietary protein levels can also influence the promotional phase of carcinogenesis. Further research is required to determine the mechanisms associated with the influence of dietary protein on both the initiation and promotional phases of carcinogenesis. 

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