Reliability-Based Electronics Shielding Design Tools

Shielding design on large human-rated systems allows minimization of radiation impact on electronic systems. Shielding design tools require adequate methods for evaluation of design layouts, guiding qualification testing, and adequate follow-up on final design evaluation

Electronics Shielding and Reliability Design Tools

It is well known that electronics placement in large-scale human-rated systems provides opportunity to optimize electronics shielding through materials choice and geometric arrangement. For example, several hundred single event upsets (SEUs) occur within the Shuttle avionic computers during a typical mission. An order of magnitude larger SEU rate would occur without careful placement in the Shuttle design. These results used basic physics models (linear energy transfer (LET), track structure, Auger recombination) combined with limited SEU cross section measurements allowing accurate evaluation of target fragment contributions to Shuttle avionics memory upsets. Electronics shielding design on human-rated systems provides opportunity to minimize radiation impact on critical and non-critical electronic systems. Implementation of shielding design tools requires adequate methods for evaluation of design layouts, guiding qualification testing, and an adequate follow-up on final design evaluation including results from a systems/device testing program tailored to meet design requirements

Clinical and laboratory predictors for plaque erosion in patients with acute coronary syndromes

Background-—Plaque erosion is responsible for 25% to 40% of patients with acute coronary syndromes (ACS). Recent studies suggest that anti-thrombotic therapy without stenting may be an option for this subset of patients. Currently, however, an invasive procedure is required to make a diagnosis of plaque erosion. The aim of this study was to identify clinical or laboratory predictors of plaque erosion in patients with ACS to enable a diagnosis of erosion without additional invasive procedures. Methods and Results-—Patients with ACS who underwent optical coherence tomography imaging were selected from 11 institutions in 6 countries. The patients were classified into plaque rupture, plaque erosion, or calcified plaque, and predictors were identified using multivariable logistic modeling. Among 1241 patients with ACS, 477 (38.4%) patients were found to have plaque erosion. Plaque erosion was more frequent in non–ST-segment elevation-ACS than in ST-segment–elevation myocardial infarction (47.9% versus 29.8%, P=0.0002). Multivariable logistic regression models showed 5 independent parameters associated with plaque erosion: age 15.0 g/dL, and normal renal function. When all 5 parameters are present in a patient with non–ST-segment elevation-ACS, the probability of plaque erosion increased to 73.1%. Conclusions-—Clinical and laboratory parameters associatedwith plaque erosion are explored in this retrospective registry study. These parametersmay be useful to identify the subset ofACS patients with plaque erosion and guide themto conservativemanagement without invasive procedures. The results of this exploratory analysis need to be confirmed in large scale prospective clinical studiesDr. Jang has received an educational grant from Abbott Vascular and Medicure. Dr. Adriaenssens has received grants and consulting fees from Abbott Vascula