title: Relative permittivity measurement during the thrombus formation process using the dielectric relaxation method for various hematocrit values.
abstract: The relative permittivity ε' and the dielectric loss ε″ for various hematocrit values H for static bovine blood condition have been measured using the dielectric relaxation method to detect thrombosis in real time. The suitable measurement frequency f m ranged within 60 kHz to 1 MHz, and the relaxation frequency of red blood cells (RBCs) f rc was observed to be 2 MHz. In the f m, the temporal change of normalized ε' exhibited a minimum (called as bottom point). The bottom point was observed to be exponentially shortened as H increased. This characteristic of the ε'* minimum is discussed from three viewpoints: during fibrin formation, direct thrombus formation, and rouleaux formation processes. ε'* during the fibrin formation process decreased over time, irrespective of f. However, ε'* in f m during the direct thrombus formation process and during the aggregation formation process increased immediately and rapidly over time. Therefore, the ε'* bottom point in f m might be the indication of micrometer-scale thrombus formation by RBC aggregation due to fibrin formation.
authors.affiliation: Division of Artificial Systems Science, Graduate Course of Mechanical Engineering, Chiba University, 1-33, Inage, Chiba, 263-8522, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Asakura
authors.affiliation: Department of Information and Computer Engineering, National Institute of Technology, Kisarazu College, 2-22-1 Kiyomidai-Higashi, Kisarazu, Chiba, 292-0041, Japan. sapkota@ieee.org.
authors.forename: Achyut
authors.initials: A
authors.lastname: Sapkota
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba, Ibaraki, 305-8564, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Maruyama
authors.affiliation: National Institute of Advanced Industrial Science and Technology, 1-2-1, Namiki, Tsukuba, Ibaraki, 305-8564, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kosaka
authors.affiliation: Department of Mechanical Engineering, Graduate School of Engineering, Kobe University, 1-1, Rokkodai, Nada, Kobe, 657-8501, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamane
authors.affiliation: Division of Artificial Systems Science, Graduate Course of Mechanical Engineering, Chiba University, 1-33, Inage, Chiba, 263-8522, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takei
mesh_terms: D000818:Animals; D002417:Cattle; D017097:Electric Impedance; D004558:Electric Stimulation; D004903:Erythrocyte Aggregation / Q000502:physiology; D005337:Fibrin; D006400:Hematocrit; D013552:Swine; D013927:Thrombosis / Q000209:etiology*
chemical_list: D005337:Fibrin
keywords: Artificial heart; Dielectric relaxation method; Red blood cell; Thrombus detection; Thrombus formation