Deterioration, four stages

Definition, Discussion, and Examples of the Four Stages of Deterioration... 

Puri et al. followed Vaddadi s work with a randomized, double-blind, placebo-controlled study of EPA in patients with end-stage HD (Puri et al., 2000). Seven patients were involved in the study, and over 6 mo, three patients improved and four deteriorated. On breaking the code all three patients who improved were on EPA, whereas all four who deteriorated were on placebo p = 0.04). Moreover, magnetic resonance imaging showed the expected ongoing neurodegenerafion with ventricular expansion on placebo, but a partial reversal with reduction of ventricular size on active treatment. 

As the cell operates, [Zn" ] increases (as the Zn electrode deteriorates) and [Cu ] decreases (as Cu plates out on the Cu electrode). Although the changes during this process occur smoothly, we can identify four general stages of operation. Figure 21.11A shows the first three. The main point to note is as the cell operates, its potential decreases ... 

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