Местоположение издательства:Piscataway, NJ, United States
Первая страница:88
Последняя страница:89
Аннотация:One of the main microrheologic parameters of blood is erythrocyte deformability, which is defined as a measure of the ability of cells to change their shape under the influence of external forces. The deformability of the erythrocytes is conventionally measured using different methods. One of the most convenient methods is based on laser diffraction by red blood cells in shear flow (ektacytometry). In ektacytometry, the information about red cells shapes is extracted from the diffraction patterns that are formed due to low-angle scattering of a laser beam while passing through a sheared low hematocrit RBC suspension. Our studies show that laser ektacytometry can be used not only to measure the mean deformability of the cells in suspension but also to measure the parameters of the distribution of erythrocytes in deformability. However, implementation of these possibilities requires a specific calibration of the ektacytometer. The calibration involves measuring the level of light intensity at various points of the observation screen relative to the light intensity in the central diffraction maximum. Direct calibration can be performed by regular photometry and digitization of the diffraction pattern in a wide area of the observation screen, including the area of the central diffraction maximum. However, such measurements are complicated by the fact that the central diffraction maximum is located in the vicinity of the point of incidence of the direct laser beam on the observation screen. Therefore, we need to search for other ways to solve this problem. One such method is proposed in this paper. Our method is based on measuring the geometric parameters of the diffraction patterns obtained in the experiments with specially prepared samples of blood («blood sample calibration»). In this paper, we derive the necessary diffractometric equations, as well as describe the procedure for the preparation of blood samples. In addition, we test the data processing algorithm, which allows for estimating the parameters of the distribution of erythrocytes in deformability.