We study, numerically and analytically, the forced transport of deformable containers through a narrow constriction. Our central aim is to quantify the competition between the constriction geometry and the active forcing, regulating whether and at which speed a container may pass through the constriction and under what conditions it gets stuck. We focus, in particular, on the interrelation betw...

Five patients with constrictive pericarditis are described, in whom the main constriction was found at operation to be concentrated in an annular band forming a hoop around the pericardial sac, at the level of the atrio-ventricular grooves. In four of them, although the constriction was predominantly at this annulus, the effect on the heart was similar to that resulting from more generalized co...

1. Both renin and angiotonin in small doses cause constriction of the arterioles in the ears of normal rabbits, as seen directly with the microscope. Capillaries appear unaffected while venules exhibit slight or no constriction with small doses and moderate constriction with large doses. The flow of blood through the tissues is not reduced except when very large doses are administered. Tyramine...

Dynamin is a dimeric GTPase that assembles into a helix around the neck of endocytic buds. Upon GTP hydrolysis, dynamin breaks these necks, a reaction called membrane fission. Fission requires dynamin to first constrict the membrane. It is unclear, however, how dynamin helix constriction works. Here we undertake a direct high-speed atomic force microscopy imaging analysis to visualize the const...

In this paper, a genetic algorithm and constriction factor based particle swarm optimization technique are proposed for solving the short term variable head hydrothermal scheduling problem with transmission line losses. The performance efficiency of the proposed techniques is demonstrated on hydrothermal test system comprising of two thermal units and two hydro power plants. the simulation resu...

A retinal arterial constriction was produced in anesthetized cats with a continuous transvitreal infusion of angiotensin I or angiotensin II (Ile-5). Constriction of vessels near the infusion cannula tip occurred over a range of angiotensin II concentrations from 10(-9) to 10(-4) molar, and was reversibly blocked by a ten-fold excess of the competitive antagonist saralasin. Constriction did not...

Actin filaments and myosin II are evolutionarily conserved force-generating components of the contractile ring during cytokinesis. Here we show that in budding yeast, actin filament depolymerization plays a major role in actomyosin ring constriction. Cofilin mutation or chemically stabilizing actin filaments attenuate actomyosin ring constriction. Deletion of myosin II motor domain or the myosi...

Neurulation is a critical period in all vertebrates and results in the formation of the neural tube, which gives rise to the CNS. Apical constriction is one of the fundamental morphogenetic movements that drives neural tube closure. Using live imaging, we show that apical constriction during the neurulation is a stepwise process driven by cell-autonomous and asynchronous contraction pulses foll...

Pulmonary hypertension may occur in the fetus in the presence of constriction of the ductus arteriosus. The feasibility of detection and quantitation of fetal ductal constriction by Doppler echocardiography was assessed in an animal preparation in which ductal constriction was created in the fetal lamb with a variable ligature causing varying degrees of fetal pulmonary hypertension (fetal pulmo...

This article presents a numerical investigation of the pulsatile flow non-Newtonian Casson fluid through rectangular channel with symmetrical local constriction on walls. The objective is to study heat transfer characteristics said under an applied magnetic field and thermal radiation. Such may find its application in devising treatments for stenosis blood arteries, designing biomechanical devi...