Ineffective cycles

The ineffectiveness of Micro-Cel for controlling exudation was conclusively demonstrated during temp-humidity cycling tests conducted on the Chaparral missile. The temp cycle used was from -4° to 103° for a 24-hour period, with missiles held at extremes for a 4-hour period and brought from one extreme to the other in eight hours. Exudate was observed on eleven of twelve missiles submitted to test (Ref 35)... 

A monohydride mechanism is not operating in reactions catalyzed by these complexes. Noyori observed that the presence of an NH or NH2 in the auxiliary ligands was crucial for catalytic activity, the corresponding dialkylamino analogs being totally ineffective. These findings indicate a novel metal-ligand bifunctional cycle (Scheme 28) KOH reacts with the pre-catalyst (87)... 

Following the reactions in Scheme 4, the olefin 13 would have to be generated before the formation of the 7r-crotyl species 2. Because the amount of the catalyst present is usually small as compared to the amount of product formed (1000 moles of product/mole catalyst), the quantity of 13 produced will not be significant and should be readily separable from the desired product. In the special case when crotyl chloride is used as the activator, hexadiene can be produced during the very first cycle of reaction, i.e., 13 = 1,4-hexadiene. Among the organic halides, the chloride derivatives are the most effective activators. Bromides are somewhat effective, while fluorides and iodide are rather ineffective (77). 

From this figure, it can be seen that in more than 60 % of the single loop control elements initially indicated as ineffective (total of 44 elements), the true ineffective element originates from the double loop learning cycle, i.e. the ineffectiveness originates from the steering element. In about only 40 % of the ineffective elements the initial single loop indication was correct. 

The Chemical Leasing (ChL) approach is a new and innovative instrument to promote sustainable management of chemicals and close the material cycles between suppliers and users of chemicals ("closing the loops"). Chemical Leasing is applicable to large companies as well as small and medium size enterprises of different sectors. Experience shows that these new models reduce ineffective use and over-consumption of chemicals and help companies to enhance their economic performance. 

The structure and properties of a network polymer are determined by the relation between the inter- and intramolecular reactions of functional groups. The latter gives rise to ineffective cycles, and has been studied fairly well3-5 7°.71-8i-85.i°8 u2 Their occurrence in the system results in the gelation point being shifted towards higher conversions, higher sol fraction, fewer elastically active chains, and smaller equilibrium modulus of the network. 

One quantitative approach to the inclusion of formation of ineffective cycles is... 

An illustrative description of the ineffective cycles is provided by the network polymer random model8,187>. The model is underlied by a conception of the network polymer structure as a combination of the accidentally associated cycles with a certain distribution by size. Scheme (27) illustrates the first members of a series of cyclic structures formed by reaction of the diepoxides with diamines (the notation i, j means a ring composed of i diepoxide and j diamine units)... 

In this case the 1,1- and 1,0-cycles turned out to be ineffective (defective). 

For equilibrium-controlled reactions, the probability of formation of the ineffective cycles depends on their thermodynamic stability. The fraction of such cycles on the stage of polymer formation can be only estimated if we know the relative constant of... 

Cyclopenta[c]quinolizines (51) reacted with acetylenic esters in boiling nitrobenzene to give cyclopenta[cd]cycl[3,3,3]azines (52). Other media were found to be ineffective, even in the presence of palladium-charcoal. The alkoxycarbonyl groups of the esters were readily removed by alkaline hydrolysis followed by vacuum pyrolysis of the resulting... 

Cyclocurcumin differs from curcumin in the p-diketone link. In this molecule, the a, p-unsaturated p-diketone moiety of curcumin is replaced by a, p-unsaturated dihydropyranone moiety. Up to now, not many biological studies are reported with cyclocurcumin except for one study on inhibition of MCF-7 tumor cell proliferation by Simon et al. [1998] where it has been found to be ineffective in inhibiting cell proliferation and arrest of cell-cycle progression. 

Os-platinum (cisplatin) binds to intracellular DNA, causing both interstrand and intrastrand cross-linking. It is a cell-cycle phase nonspecific agent. Os-platinum, which is ineffective orally, is used for testicular, bladder, and head and neck cancers. It precipitates nephrotoxicity, ototoxicity, and gastrointestinal injury. 

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