Compound Object State Pattern

Suppose the compound state transition only involves structure changes and undo only needs to recover the structure and the compound state. Figure 12.6 is the class diagram of the Memento Pattern for the Compound object. 

The nature of study objectives in environmental research is often multivariate. Several pollutant patterns from different, sometimes unknown, sources may occur. The state of pollution of a sampling point, line, or area in any environmental compartment, whether atmosphere, water, soil, or biota, depends mostly on the nature of the different sources of pollution. Stack emissions are characterized by a multi-element pattern. Waste water effluents contain different contaminants, ranging from heavy metals to cocktails of organic compounds. 

Other catalysts with firmly bound prosthetic groups, including the iron-porphyrin-bearing cytochromes, have been shown to undergo reversible oxidation. Therefore, it would form a consistent pattern if the hydroperoxidases were also to be oxidized and reduced. To explain the action of these enzymes several schemes have been advanced in which the iron shifts from the ferric to the ferrous state and back. All of these schemes have been criticized when applied to catalase because of the inability to detect a ferrous enzyme by magnetic measurements or by inhibition of the reaction with CO. It does not seem that these objections are overwhelming, as the ferrous state may be very short-lived, and escape detection by physical means, and the reduced enzyme may have less affinity for CO than those enzymes that are inhibited by this compound. 

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