External unipolar

Manic-depressive illness connotes a psychotic disorder of affect that occurs episodically without external cause. In endogenous depression (melancholia), mood is persistently low. Mania refers to the opposite condition (p. 234). Patients may oscillate between these two extremes with interludes of normal mood. Depending on the type of disorder, mood swings may alternate between the two directions (bipolar depression, cyclothymia) or occur in only one direction (unipolar depression). 

The principal method of introducing metal impurities into early pinch discharges was considered to be arcing. The externally applied voltages, although low, still permit the occurrence of unipolar arcing between the plasma and the wall when driven by the sheath potential. Local electron emission from a cathode spot is balanced by a uniform flow back to the surface of energetic electrons in the tail of the Maxwellian distribution. 

Figure 5.13 (a) Initial external excitation by a unipolar electrode and (b) propagation in both... 

Fig. 1.23 Three examples of fractured unipolar leads occurring at points of stress. A In the neck where the lead enters the external jugular vein. There is a sharp bend in the lead at the venous entry site and both limbs of the lead move differently with neck movement. B Within the right atrium. The lead is encased in a short endocardial tunnel, where it makes contact with the wall as it turns to enter the right ventricle. Again both limbs move differently with cardiac contractions. C At the lead connector site. There is a sharp bend in the lead after it emerges from the connector.

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