Comparison between Auditory and Visual Simple Reaction Times

Objective: The purpose of this study was to find out whether the simple reaction time was faster for auditory or visual stimulus and the factors responsible for improving the performance of the athlete. Methodology: 14 subjects were as- signed randomly into groups consisting of 2 members. Both the members from each group performed both the visual and auditory tests. The tests were taken from the DirectRT software program from a laptop. The DirectRT software consists of Testlabvisual and Testlabsounds to test the reaction times to visual and auditory stimuli. The 2 members from each group completed both the visual and auditory reaction times, the data was taken and the mean reaction time was calculated excluding the first and last values. Results: The results show that the mean visual reaction time is around 331 milliseconds as compared to the mean auditory reaction time of around 284 milliseconds. Conclusion: This shows that the auditory reaction time is faster than the visual reaction time. And also males have faster reaction times when compared to females for both auditory as well as visual stimuli.

Finite element analysis of a percutaneous aortic valve stent design

Aim: This paper discusses the design and Finite Element Analysis (FEA) of a Percutaneous Aor-tic Valve Stent. The aim of this study was to model a percutaneous aortic valve stent and subject it to finite element analysis. The design process was carried out to meet the functional and surgical requirements. Methods and Results: Analysis was done with different materials with loads ranging from 50 kgf/mm²to 73 kgf/mm². These forces were selected because these val-ues are far greater than the normal human blood pressure which ranges from 10kPa to 16kPa. It was also to understand the mechanical behavior of different stent materials under such high pressures. A stent model was generated and its physical, mechanical and behavioral properties were studied. Finite element analysis and simulation of the model enhanced the designer to optimize the geometry suitable for perform-ance during and after implantation. The design objective for the stent is to have long term du-rability, low thrombogenicity, resistance to mi-gration and paravalvular leak. Conclusion: The analysis performed in this paper may aid in understanding the stent’s tolerable pressures ranges in comparison with the physiological pressures exerted by the heart and cardiac blood flow during abnormal cardiovascular conditions.

Evaluation of Stress Strain Patterns in a Stentless Aortic Valve and Its Leaflets

Objective: To design a new trileaflet aortic valve and investigate its mechanical behavior using finite ele- ment methods. Background: Quantification of aortic valve deformation during cardiac cycle is essential in understanding normal and pathological valvular function and eventually in the design of valves. We have designed and analyzed a new tissue valve model to investigate the mechanics of the valve and its components. Methods: Steps involves in 3D CAD based geometric modeling of a trileaflet aortic valve and the effects of different component dimensions on the mechanical behavior of valve is presented in this paper. Conceptual designing of individual components was used to build the total geometric model. Different physiological pressures were applied on the valve model and its deformation patterns were studied. Results: A new geometric model of a trileaflet aortic valve was designed. Its mechanical behavior was studied. Geometric analysis and simulation of these models enhanced the designer to optimize the geometry suitable for performance during and after implantation. Conclusion: The geometry-based model presented here allows determining quickly if the new set of valve component dimensions results in a functional valve. This is of great interest to designers of new prosthetic heart valve models, as well as to surgeons involved in valve- sparing surgery.