During symmetric division cells undergo large constriction deformations at a stable midcell site. Using a variational approach, we investigate the mechanical route for symmetric constriction by computing the bending energy of deformed vesicles with rotational symmetry. Forces required for constriction are explicitly computed at constant area and constant volume, and their values are found to be...

Cytokinesis involves constriction of a contractile actomyosin ring. The mechanisms generating ring tension and setting the constriction rate remain unknown because the organization of the ring is poorly characterized, its tension was rarely measured, and constriction is coupled to other processes. To isolate ring mechanisms, we studied fission yeast protoplasts, in which constriction occurs wit...

In the original Particle Swarm Optimization (PSO) formulation, convergence of a particle towards its attractors is not guaranteed. A velocity constraint is successful in controlling the explosion, but not in improving the fine-grain search. Clerc and Kennedy studied this system, and proposed constriction methodologies to ensure convergence and to fine tune the search. Thus, they developed diffe...

     Introduction: Objective: This study aimed to assess the possible variations in root canal anatomy and topography of the apices of first and second maxillary molars. Materials and methods: A total of 67 first and second maxillary permanent molars were collected. Access cavity was prepared and 2% methylene blue was injected. The teeth were demineralized by 5% nitric acid and cleared with met...

Adrenergic constriction of skeletal muscle arterioles, particularly small terminal arterioles, is opposed by decreased blood flow or increased metabolic rate. Our previous studies indicate that neural constriction of large arterioles, which have both postjunctional a1and a2-adrenoceptors, is mediated by a1-receptors; small arterioles depend on a2-receptors. Also, a,2 but not ca, constriction is...

Intravital microscopy was used to study the effect of endothelium-derived relaxing factor (EDRF) on microvascular adrenoceptor sensitivity in rat cremaster skeletal muscle. NG-Monomethyl L-arginine (L-NMMA, 1-300 ,uM), an inhibitor ofEDRF formation, produced concentration-dependent constriction of arterioles and venules. When an intermediate amount of a-l versus a2-adrenoceptor tone was first p...

conclusions coq10 abolished neuropathic pain in cci rats. prevention of cell loss might be attributed to the analgesic effect of coq10. hence, it might be used as a therapeutic intervention for neuropathic pain. background oxidative stress contributes to neuropathic pain. coenzyme q10 (coq10) is used for the treatment of neurodegenerative diseases. however, there is no report regarding the ther...

Umbilical artery Doppler velocimetry waveform notching has long been associated with umbilical cord abnormalities, such as distortion, torsion, and/or compression (i.e., constriction). The physical mechanism by which the notching occurs has not been elucidated. Flow velocity waveforms (FVWs) from two-dimensional pulsatile flows in a constricted channel approximating a compressed umbilical cord ...

Studies were performed on anesthetized saline-loaded dogs to delineate the factors involved in the antinatriuretic effect of acute constriction of the thoracic (TIVC) and abdominal (AIVC) inferior vena cava. Acute TIVC constriction lowered cardiac output and arterial blood pressure and reduced urinary sodium excretion 48%; the same degree of reduction in renal perfusion pressure by suprarenal a...

Studies were performed on anesthetized saline-loaded dogs to delineate the factors involved in the antinatriuretic effect of acute constriction of the thoracic (TIVC) and abdominal (AIVC) inferior vena cava. Acute TIVC constriction lowered cardiac output and arterial blood pressure and reduced urinary sodium excretion 48%; the same degree of reduction in renal perfusion pressure by suprarenal a...