PROBLEM Effective tamponade of a Descemet-stripping endothelial keratoplasty graft with a gas bubble requires that there is no route for the bubble to escape into the posterior chamber. SOLUTION Exchange the angle-supported anterior-chamber intraocular lens (IOL) for an iris-enclaved Artisan IOL and position the IOL haptics over the peripheral iridectomy to occlude it to the extent that no ga...

In this article, a new approach to the study of human–computer interaction (HCI) from the activity theory perspective is presented. A computer-based task was selected for demonstration purposes. Due to its complexity, variability, and number of mental components, the selected computer-based task presented difficulties in observation and formal description. Other tasks involving computers bared ...

AbsirmAn algebraic approach for the controllability analy sir of a class of h) brid control syslems rallcd cootrolled awltching linear h)hrid r y a e m r is proposcd. A rufficicnl and neccrrar, condition is obtained bared on the algebraic manipulalion 01 related system matriccs. This consequence is directly oriented Io numerical romputnlion of Ibe controllability. Beside that, the existing resu...