Coordinating the simultaneous conduction of SASD circuits is not subjected to the same difficulties that plague MOV designs.
Quality SASD suppressors should not be designed or expected to self-sacrifice during a typical transient surge event.
The MOV stages cannot be coordinated to conduct reliably in conjunction with the SASD stages.
Often, premature suppressor failure is realized by the SASD stages because they simply do not incorporate enough diodes to dissipate proper levels of transient energy.
SASD components are not troubled with voltage protection limitations, or degradation problems of MOV components.
Sialic acid (free and as a conjugate) has been extracted from the urine of individuals with SASD and sialidoses, respectively, and characterized by [sup.1]H-NMR spectroscopy (12-14); however, the technique has not been used for direct diagnosis from unextracted urine.
We carried out [sup.1]H-NMR analysis of urine from five patients with SASD (two with the infantile form, one with the intermediate form, and two patients with Salla disease) and compared the urinary sialic acid excretion determined by colorimetric analysis and [sup.1]H-NMR spectroscopy.
Urine samples from patients with SASD were obtained as part of a selective screening program for inborn errors of metabolism.
Spectra for urine from an 11-month-old infant, screened for a suspected metabolic disorder, and from a 2-month-old infant with the severe form of SASD are shown in Fig.
The results demonstrate that the five cases of SASD studied gave [sup.1]H-NMR urine spectra that are diagnostic.
Although SASD is rare, the NMR method used is identical to that previously used for detecting other metabolic disorders and includes the concurrent determination of creatinine (17).