transcatheteraortic valve implantation, first introduced in 2002, has been established as an alternative modality for patients deemed not suitable for open-heart surgery. the anatomical vicinity of the atrioventricular node and the his bundle to the non-coronary and rightcoronary aortic cusps predisposes patients to conduction abnormalities in case of severe calcification or mechanical trauma d...

nanocomposites made of carbon nanotube (cnt) bundles have attracted researchers’ attention due to their unusual properties such as: light weight, flexibility and stiffness.  in this paper, the effects of straight and rope-shaped bundles on nanocomposite effective mechanical properties are investigated.  first, fea models are created consisting of cnts with different shapes of straight and rope-...

We characterize the natural diagonal almost product (locally product) structures on the tangent bundle of a Riemannian manifold. We obtain the conditions under which the tangent bundle endowed with the determined structure and with a metric of natural diagonal lift type is a Riemannian almost product (locally product) manifold, or an (almost) para-Hermitian manifold. We find the natural diagona...

bubble columns are gas- liquid contactors that are widely used in chemical and bio- chemical industries. high mixing that result in high heat and mass transfer rates are amongst their advantages. heat transfer in a bubble column having a bundle of heaters investigated and the variation of heat transfer coefficient with variation in heaters pitch to diameter ratios in a bundle of heaters reporte...

Let $p:Xlo B$ be a locally trivial principal G-bundle and $wt{p}:wt{X}lo B$ be a locally trivial principal $wt{G}$-bundle. In this paper, by using the structure of principal bundles according to transition functions, we show that $wt{G}$ is a covering group of $G$ if and only if $wt{X}$ is a covering space of $X$. Then we conclude that a topological space $X$ with non-simply connected universal...

There is controversy in the literature regarding a number of topics related to anterior cruciate ligament (ACL)reconstruction. The purpose of this article is to answer the following questions: 1) Bone patellar tendon bone (BPTB) reconstruction or hamstring reconstruction (HR); 2) Double bundle or single bundle; 3) Allograft or authograft; 4) Early or late reconstruction; 5) Rate of return to sp...

the main purpose of this study is to perform numerical simulation of nanofluids as the coolant in vver-440 fuel rod bundle. the fuel rod bundle contains 60 fuel rods with length of 960 mm and 4 spacer grids. in vver-440 fuel rod bundle the coolant fluid (water) is in high pressure and temperature condition. in the present thermo-hydraulic simulation, water-al2o3 nanofluids containing various vo...

catheter ablation is an accepted, highly effective modality of treatment for cardiac arrhythmias in children. the success rate depends on the operator’s experience, especially in cases involving complex anatomies. we hereby report our recent experience of successful ablation of accessory pathways in three children with complex congenital heart diseases. the first case was a 7-year-old girl with...

The main purpose of this study is to perform numerical simulation of nanofluids as the coolant in VVER-440 fuel rod bundle. The fuel rod bundle contains 60 fuel rods with length of 960 mm and 4 spacer grids. In VVER-440 fuel rod bundle the coolant fluid (water) is in high pressure and temperature condition. In the present Thermo-hydraulic simulation, water-AL2O3 nanofluids containing various vo...

there is controversy in the literature regarding a number of topics related to anterior cruciate ligament (acl)reconstruction. the purpose of this article is to answer the following questions: 1) bone patellar tendon bone (bptb) reconstruction or hamstring reconstruction (hr); 2) double bundle or single bundle; 3) allograft or authograft; 4) early or late reconstruction; 5) rate of return to sp...