A Tool for Developing Diagnostics for a Digital Switching System

Testing large digital systems is difficult. Throughout the literature on “design for testability,” the existence of diagnostic software is assumed. However, developing such software is a significant task. A hardware test fixture was developed to assist in the development of diagnostic software for a Stromberg-Carlson Corporation switching system. Two circuit boards were designed, constructed, and debugged

Permanent tissue damage in multiple sclerosis lesions is associated with reduced pre-lesion myelin and axon volume fractions

BACKGROUND: The use of advanced magnetic resonance imaging (MRI) techniques in MS research has led to new insights in lesion evolution and disease outcomes. It has not yet been determined if, or how, pre-lesional abnormalities in normal-appearing white matter (NAWM) relate to the long-term evolution of new lesions. OBJECTIVE: To investigate the relationship between abnormalities in MRI measures of axonal and myelin volume fractions (AVF and MVF) in NAWM preceding development of black-hole (BH) and non-BH lesions in people with MS. METHODS: We obtained magnetization transfer and diffusion MRI at 6-month intervals in patients with MS to estimate MVF and AVF during lesion evolution. Lesions were classified as either BH or non-BH on the final imaging visit using T(1) maps. RESULTS: Longitudinal data from 97 new T(2) lesions from 9 participants were analyzed; 25 lesions in 8 participants were classified as BH 6–12 months after initial appearance. Pre-lesion MVF, AVF, and MVF/AVF were significantly lower, and T(1) was significantly higher, in the lesions that later became BHs (p  0.05). CONCLUSION: The present work demonstrated that pre-lesion abnormalities are associated with worse long-term lesion-level outcome