John B. Johnston

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There appears to be a need for an intuitive implementable cell-based model of the semantics of algorithm execution. It is contended that for block structured processes, such a model must be based on the concepts of nested blocks, access environments, labels, and cell retention. A model so based, the contour model, is introduced by illustrating the execution(More)
The reaction of 2,4-dinitroanilinomaleimide with sulphite which has been claimed as the basis of a suitable colorimetric assay for the anion was carefully re-examined. The sulphite-imide addition product provides a suitable and specific qualitative test for sulphite after separation by paper chromatography but the method as previously used is probably(More)
A simple, convenient, nondestructive method is described for the quantitative determination of bound hyaluronan. The method is based on the binding of the cationic dye Toluidine Blue O to the D-glucuronate component of the hyaluronan repeat disaccharide. Quantification is accomplished without interference by the dye's metachromatic properties. The method is(More)
In block structured languages, upon entry to a block or procedure, storage is allocated for the identifiers declared in the block or procedure. There are two choices as to when to deallocate this storage: 1) upon exit from the block or procedure, 2) when the storage becomes inaccessible. In the deletion strategy, storage for blocks and procedures is(More)
BACKGROUND Since the 2001 "black box" warning on droperidol, its use in the prehospital setting has decreased substantially in favor of haloperidol. There are no studies comparing the prehospital use of either drug. The goal of this study was to compare QTc prolongation, adverse events, and effectiveness of droperidol and haloperidol among a cohort of(More)
In conjunction with an earlier paper, this step toward machine design based on the structure of nested-declaration pure-procedure multiple-activity algorithms describes: the declaration, flow-of-control, and some data-addressing mechanisms of such algorithms; the dynamic Saguaro-Garden data-access-providing structure of their Records of Execution ; and(More)
The Synthesizer-Generator (or simply Syn-Gen) is a software tool for building context sensitive editors. It has been applied to a wide variety of applications, ranging from programing language editors to editors that insure balanced chemical equations. The context sensitivity is provided by using attribute grammars. We provide an introduction to Syn-Gen and(More)