BACKGROUND The durability of aortic valve-sparing procedures is negatively affected by increased leaflet stress in the absence of normally shaped sinuses of Valsalva. We compared valve motion after remodeling procedures using a standard conduit and a specifically designed aortic root conduit. METHODS Echocardiographic studies of the aortic valve dynamics were performed in 14 patients after re...

This experimental work was concerned with comparison of inlet valve actuation strategies in a thermodynamic single cylinder spark ignition research engine equipped with a mechanical fully variable valvetrain on both the inlet and exhaust. The research involved study of the effects of the valvetrain on combustion, fuel economy and emissions when used to achieve variable valve timing alone and wh...

PURPOSE To present a novel design of an implantable glaucoma valve based on ferrofluidic nanoparticles and to compare it with a well-established FDA approved valve. SETTING Massachusetts Eye & Ear Infirmary, Boston, USA. METHODS A glaucoma valve was designed using soft lithography techniques utilizing a water-immiscible magnetic fluid (ferrofluid) as a pressure-sensitive barrier to aqueous ...

Introduction The opening and closing behavior of the valve is a delicate interaction between blood flow and geometrical and stiffness properties of the heart valve leaflets and aortic root. Numerical analysis of the opening and closing behavior is complicated by the three-dimensional finite motion of the very flexible leaflets in a compliant system of fluid and structure. Fluid-structure intera...

OBJECTIVES Real-time monitoring of the aortic valve function and the loading state of the left ventricle (LV) during mechanical circulatory support is essential. Therefore, we developed a system that determines accurately the aortic valve closing moment based on integrals derived from the pump inlet pressure and the pump power [pressure-power area (PPA)]. METHODS A Deltastream diagonal pump w...

Of seven patients with pulmonary hypertension, two had marked and one had moderate retardation of the echocardiographic anterior mitral valve leaflet closing motion, suggestive of mitral stenosis. In each patient, however, mitral stenosis was excluded by hemodynamic or anatomic criteria. The reason for the abnormal mitral valve motion was considered to be a reduced rate of left ventricular dias...

Particle Image Velocimetry (PIV) is an important technique in studying blood flow in heart valves. Previous PIV studies of flow around prosthetic heart valves had different research concentrations, and thus never provided the physical flow field pictures in a complete heart cycle, which compromised their pertinence for a better understanding of the valvular mechanism. In this study, a digital P...

A 72-year-old man with calcific aortic stenosis and complete heart block was noted to have an intermittent diastolic murmur. Using combined echocardiography and phonocardiography, it was demonstrated that the murmur occurred while the mitral valve was closing. This suggested that antegrade flow across a closing mitral orifice is of etiologic importance in the production of the murmur. Atrial so...

48 V mild hybrid electric vehicles (MHEVs) are considered to the prospective near-term solution for cost-effective vehicle electrification. In this study, fuel consumption improvement of various synergistic engine technologies was experimentally investigated with a P0 hybridization. The details application and optimization each technology were effect quantitatively identified. A combination inc...

OBJECTIVE Recently, various modifications have been made to aortic root replacement procedures to include the pseudosinus in the synthetic graft, but its effect on valve function still remains to be elucidated. The purpose of this study was to compare the flow dynamics and its influence on the stress/strain in the valve leaflet in two types of aortic root, either with or without the pseudosinus...