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Purpose: This paper aims to investigate a mathematical model with numerical simulation for bacterial growth in the heart valve. Design/methodology/approach: For antibacterial activities and antibodies properties, nanoparticles have been used. As antibiotics are commonly thought to be homogeneously dispersed through the blood, therefore, non-Newtonian fluid of Casson micropolar blood flow in the heart valve for two dimensional with variable properties is used. The heat transfer with induced magnetic field translational attraction under the influence of slip is considered for the resemblance of the heart valve prosthesis. The numeral results have been obtained by using the Chebyshev pseudospectral method. Findings: It is proven that vascular resistance decreases for increasing blood velocity. It is noted that when the magnetic field will be induced from the heart valve prosthesis then it may cause a decrease in vascular resistance. The unbounded molecules and antibiotic concentration that are able to penetrate the bacteria are increased by increasing values of vascular resistance. The bacterial growth density cultivates for upswing values of magnetic permeability and magnetic parameters. Originality/value: To the best of the authors' knowledge, this is the first study to investigate a mathematical model with numerical simulation for bacterial growth in the heart valve. [ABSTRACT FROM AUTHOR]

This paper is Part 2 of a study of blood flow across cardiovascular stenoses. In Part 1, we developed a rigorous mathematical approach for deriving a pressure field from experimental data for a velocity field that can be obtained by direct measurement. In this Part, existing methods for quantifying stenoses, with specific reference to cardiac valves, are reviewed. Using the mathematically rigorous and physically reasonable approach that we developed in Part 1, for a pre-specified flow velocity field proximal to the stenosis and pressure waveform field distal to the stenosis, we ascertain the intra-stenosis and distal flow velocity field, pressure field proximal to and within the stenosis, and energy dissipation, all as functions of position and time. The computed dissipation, kinetic energy and pressure are then presented in an idealized geometry, but relevant to a realistic geometry, with a symmetric stenosis. [ABSTRACT FROM AUTHOR]

The non-invasive determination of the pressure (mean normal stress) in a flowing fluid has ramifications in a variety of important problems: the flow of blood in blood vessels, flows taking place in inaccessible locations in complex internal geometries that occur in mechanical systems, etc. In this paper we discuss a rigorous new mathematical procedure for the determination of the pressure (mean normal stress) field, from data for the velocity field that can be obtained through imaging procedures such as 4D magnetic resonance imaging or echocardiography. We then use the procedure to demonstrate its efficacy by considering flows in an idealized geometry with a symmetric and asymmetric obstruction. We delineate the superiority of the method with regard to the methods that are currently in place. In Part 2 of this two part paper, we study the loss of pressure and the dissipation that occurs due to the flow of blood across a diseased valve (the pressure loss being an important indicator of the extent of the valvular disease) as well as the flow taking place in a realistic cerebral aneurysm. [ABSTRACT FROM AUTHOR]

Abstract: We develop an overset-curvilinear immersed boundary (overset-CURVIB) method in a general non-inertial frame of reference to simulate a wide range of challenging biological flow problems. The method incorporates overset-curvilinear grids to efficiently handle multi-connected geometries and increase the resolution locally near immersed boundaries. Complex bodies undergoing arbitrarily large deformations may be embedded within the overset-curvilinear background grid and treated as sharp interfaces using the curvilinear immersed boundary (CURVIB) method (Ge and Sotiropoulos, J Comput Phys, 2007). The incompressible flow equations are formulated in a general non-inertial frame of reference to enhance the overall versatility and efficiency of the numerical approach. Efficient search algorithms to identify areas requiring blanking, donor cells, and interpolation coefficients for constructing the boundary conditions at grid interfaces of the overset grid are developed and implemented using efficient parallel computing communication strategies to transfer information among sub-domains. The governing equations are discretized using a second-order accurate finite-volume approach and integrated in time via an efficient fractional-step method. Various strategies for ensuring globally conservative interpolation at grid interfaces suitable for incompressible flow fractional step methods are implemented and evaluated. The method is verified and validated against experimental data, and its capabilities are demonstrated by simulating the flow past multiple aquatic swimmers and the systolic flow in an anatomic left ventricle with a mechanical heart valve implanted in the aortic position. [Copyright &y& Elsevier]

Background: The efficacy of cardiac screening programs for individuals in competitive athletics and high-risk occupations such as commercial and military aviation continues to be highly debated. For the past 12 yr, all United States Air Force (USAF) pilot applicants have undergone screening echocardiography. Methods: All available studies were reviewed for disqualifying (DQ) diagnoses. Findings were analyzed and compared to current USAF waiver policy. Results: Between inception in March 1994 and 01 September 2006, there were 20,208 screening echocardiograms performed. Of these, 294 (1 .45%) were initially read as disqualifying. The most common diagnoses were bicuspid aortic valves with mild or less aortic insufficiency (N = 154, 0.76%), mitral valve prolapse with mild or less mitral regurgitation (N = 51, 0.25%), and trileaflet aortic valve with mild aortic insufficiency (N = 58, 0.29%). Evolution of USAF waiver policy has now rendered these diagnoses waiverable for entry into pilot training. Under current policy, 285/294 would be eligible for an unrestricted waiver, leaving only 9 individuals "DQ/no-waiver" (0.0445%). There were no cases of hypertrophic cardiomyopathy. Although the number of USAF pilot applicants has increased in recent years, the DQ/no-waiver rate has actually decreased, with only a single DQ/no-waiver finding since 2004 (N = 5802 studies; 0.01 72%). Discussion: The infrequency of positive findings in this large cohort of screening echocardiography raises questions about the appropriateness of such programs. Under current USAF policy, it is not efficacious to perform screening echocardiography on all pilot applicants. [ABSTRACT FROM AUTHOR]