The mechanism of action of diphenylhydantoin (DPH) on re-entrant ventricular arrhythmias (RVA) was studied in dogs 3-7 days following ligation of the anterior descending coronary artery utilizing direct recordings of the re-entrant pathway (RP) from the epicardial surface of the infarction zone (IZ). DPH in a therapeutic dose consistently prolonged refractoriness of potentially RP in the IZ. Th...

Foam materials based on metal and several polymers were transformed so that their cellular architectures became re-entrant, ie. with inwardly protruding cell ribs. Foams with re-entrant structures exhibited negative Poisson's ratios as well as greater resilience than conventional foams. Foams with negative Poisson's ratios were prepared using different techniques and materials and their mechani...

The effect of lidocaine on re-entrant ventricular arrhythmias (RVA) was studied in dogs 3-7 days following ligation of the anterior descending coronary artery; direct recordings were made of the re-entrant pathway (RP) from the epicardial surface of the infarction zone (IZ). Lidocaine in a therapeutic dose consistently prolonged refractoriness of potentially RP(s) in the IZ and produced a highe...

Programmed electrical stimulation of the heart uncovered unusual findings in four patients suffering from supraventricular tachyeardias. They included 1) two supraventricular tachyeardias of different location and frequency in the same patient, 2) increase in rate of a re-entrant atrioventricular (A-V) nodal tachycardia followed by the development of 2-to-1 A-V block, 3) a "gap" in A-V conducti...

In this paper, we study the re-entrant no-wait flexible flowshop scheduling problem with makespan minimization objective and then consider two parallel machines for each stage. The main characteristic of a re-entrant environment is that at least one job is likely to visit certain stages more than once during the process. The no-wait property describes a situation in which every job has its own ...

Fracture toughness of re-entrant foam materials with a negative Poisson's ratio is explored experimentally as a function of permanent volumetric compression ratio, a processing variable. JIC values of toughness of negative Poisson's ratio open cell copper foams are enhanced by 80%, 130%, and 160% for permanent volumetric compression ratio values of 2.0, 2.5, and 3.0, respectively, compared to t...

There is a close interrelationship between atrial fibrillation (AF) and atrial flutter (AFL). Atrial fibrillation of variable duration precedes the onset of AFL in almost all instances; during AF, the functional components needed to complete the AFL re-entrant circuit, principally a line of block (LoB) between the vena cavae, are formed; if this LoB does not form, classical AFL does not develop...

In the whole heart, millions of cardiac cells are involved in ventricular fibrillation (VF). Experimental studies indicate that VF is sustained by re-entrant activity, and that each re-entrant wave rotates around a filament of phase singularity. Filaments act as organising centres, and offer a way to simplify and quantify the complex spatio-temporal behaviour observed in VF. Where a filament to...