1-2hit |
Tahseen EJAZ Tadashi TAKEMAE Yukio KOSUGI Kazuhiro MATSUI Shinichi OKUBO Minoru HONGO
An electronic model of the coronary vessel consisting of resistor, capacitor and Field Effect Transistor (FET) is proposed in order to perform a dynamic simulation of the left coronary circulation and to clarify its mechanisms. Based on this model, an equivalent circuit of the coronary circulation is constructed that is divided into subepicardial and subendocardial layers and consists of segments of artery, arteriole, capillary, venule and vein for both the layers. In this simulation, the observed flow waveform of the left main artery showed dominance of flow in diastole as compared to that in systole. In epicardium, inverse venous flow was observed in early systole. These simulated waveforms are similar to those in real left coronary circulation observed by physiological and clinical researchers. Among all the segments of intramyocardium, only the venules were found to possess a time-varying resistance characteristics. From the results of this study, it is considered that the combination of resistance and capacitance of the vessel acts as an integrator and a differentiator for blood pressure and intramyocardial pressure, respectively and that the effects of integration of blood pressure and differentiation of intramyocardial pressure play a very important role in determining the factors influencing the left coronary circulation.
Tahseen EJAZ Tomohiro HORIUCHI Gosuke OHASHI Yoshifumi SHIMODAIRA
A set of three optical filters was designed and a camera system was developed using these filters in order to capture high-fidelity colors within the gamut of vision. Photographs of a number of highly saturated colors and a combination of the Macbeth chart and 18 pieces of clothing samples of various colors were taken. A 39 matrix was used to convert the camera output signals into XYZ tristimulus data. The tristimulus values of the colors were compared with those of the images captured by the camera. The average color difference, ΔE, for these samples were found to be 2.16 and 1.18, respectively.