Hardware synthesis from DDL description

The details of digital systems can be conveniently input into the design automation system by means of hardware description language (HDL). The computer aided design and test (CADAT) system at NASA MSFC is used for the LSI design. The digital design language (DDL) was selected as HDL for the CADAT System. DDL translator output can be used for the hardware implementation of the digital design. Problems of selecting the standard cells from the CADAT standard cell library to realize the logic implied by the DDL description of the system are addressed

Striking enhancement at the site of radiation for nivolumab-induced Stevens-Johnson syndrome

Stevens-Johnson syndrome is a rare adverse cutaneous drug reaction characterized by epidermal detachment of <10% body surface area with an average mortality rate of 1-5%. The mechanism of SJS is not fully understood. Nivolumab is a monoclonal antibody directed against programmed cell death-1 protein (PD-1), a receptor with immune checkpoint inhibitory and antineoplastic activities. We present a case of SJS in a patient being treated with anti-PD-1 therapy nivolumab for metastatic squamous cell carcinoma of the oropharynx. This case is unusual because of the severe accentuation with striking enhancement at his prior radiation site and in the cutaneous region with heavier tumor burden from his metastatic disease. This reaction may give insight to the underlying pathophysiology of SJS, suggesting that immune checkpoint inhibitors can activate T-cells to target keratinocytes and that external factors may be involved in creating distinct epitopes for T-cell recognition. We hope this case adds to the body of knowledge in the pathogenesis of Stevens-Johnson syndrome and cutaneous adverse events seen with checkpoint inhibitors

The effect of oxygen starvation on ignition phenomena in a reactive solid containing a hot-spot

In this paper, we explore the effect of oxygen supply on the conditions necessary to sustain a self-propagating front from a spherical source of heat embedded in a much larger volume of solid. The ignition characteristics for a spherical hot-spot are investigated, where the reaction is limited by oxygen, that is, reactant + oxygen ? product. It is found that over a wide range of realistic oxygen supply levels, constant heating of the solid by the hot-spot results in a self-propagating combustion front above a certain critical hot-spot power; this is clearly an important issue for industries in which hazard prevention is important. The ignition event leading to the formation of this combustion wave involves an extremely sensitive balance between the heat generated by the chemical reaction and the depletion of the reactant. As a result, for small hot-spot radii and infinite oxygen supply, not only is there a critical power above which a self-sustained combustion front is initiated there also exists a power beyond which no front is formed, before a second higher critical power is found. The plot of critical power against hot-spot radius thus takes on a Z-shape appearance. The corresponding shape for the oxygen-limited reaction is qualitatively the same when the ratio of solid thermal diffusion to oxygen mass diffusion (N) is small and we establish critical conditions for the initiation of a self-sustained combustion front in that case. As N gets larger, while still below unity, we show that the Z-shape flattens out. At still larger values of N, the supercritical behaviour becomes increasingly difficult to define and is supplanted by burning that depends more uniformly on power. In other words, the transition from slow burning to complete combustion seen at small values of N for some critical power disappears. Even higher values of N lead to less solid burning at fixed values of power