Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Susumu Kudo Last modified date:2018.06.14

Professor / Bioengineering / Department of Mechanical Engineering / Faculty of Engineering


Papers
1. Alireza Karimi, Reza Razaghi, Hasan Biglari, Toshihiro Sera, Susumu Kudo, Collision of the glass shards with the eye
A computational fluid-structure interaction model, Journal of Chemical Neuroanatomy, https://doi.org/10.1016/j.jchemneu.2017.12.008, 90, 80-86, 2018.07, The main stream of blunt trauma injuries has been reported to be related to the automobile crashes, sporting activities, and military operations. Glass shards, which can be induced due to car accident, earthquake, gunshot, etc., might collide with the eye and trigger substantial scarring and, consequently, permanently affect the vision. The complications as a result of the collision with the eye and its following injuries on each component of the eye are difficult to be diagnosed. The objective of this study was to employ a Three-Dimensional (3D) computational Fluid-Structure Interaction (FSI) model of the human eye to assess the results of the glass shards collision with the eye. To do this, a rigid steel-based object hit a Smoothed-Particle Hydrodynamics (SPH) glass wall at the velocities of 100, 150, and 200 m/s and, subsequently, the resultant glass shards moved toward the eye. The amount of injury, then, quantified in terms of the stresses and strains. The results revealed the highest amount of stress in the cornea while the lowest one was observed in the vitreous body. It was also found that increasing the speed of the glass shards amplifies the amount of the stress in the components which are located in the central anterior zone of the eye, such as the cornea, aqueous body, and iris. However, regarding those components located in the peripheral/posterior side of the eye, especially the optic nerve, by increasing the amount of velocity a reduction in the stresses was observed and the optic nerve is hardly damaged. These findings have associations not only for understanding the amount of stresses/strains in the eye components at three different velocities, but also for providing preliminary information for the ophthalmologists to have a better diagnosis after glass shards (small objects impact) injuries to the eye..
2. Masataka Arai, Toshihiro Sera, Takumi Hasegawa, Susumu Kudo, Spatial and temporal translocation of PKCα in single endothelial cell in response to mechanical stimulus, Experimental Cell Research, https://doi.org/10.1016/j.yexcr.2018.03.038, 367, 2, 205-215, 2018.06, Endothelial cells (ECs) are exposed to various environmental forces, and a Ca2+ wave is occurred in mechanical stimulated cells. Pharmacological studies reveal that the translocation of protein kinase Cα (PKCα) to the membrane is observed simultaneously with intracellular Ca2+ wave. In this study, we investigate whether and how the kinetics of PKCα in ECs is induced in response to mechanical stress. The results show that a mechanical stimulus induced biphasic and directional PKCα translocation; PKCα initially translocated near or at the membrane and then accumulated at the stimulus point. The initial translocation occurred simultaneously with Ca2+ increase. Initial translocation was inhibited in spite of Ca2+ increase when the diacylglycerol (DAG) binding domain of PKCα was inhibited, suggesting that translocation requires intracellular Ca2+ increase and DAG. On the other hand, secondary translocation was delayed, occurring after the Ca2+ wave; however, this translocation occurred even when Ca2+ release from the endoplasmic reticulum was inhibited, while it did not occur when the mechanosensitive (MS) channel was inhibited. These results indicated that at least Ca2+ influx from extracellular space through MS channel is required. Our results support the implication of PKCα in the Ca2+ signaling pathway in response to mechanical stress in ECs..
3. Toshihiro Sera, Tateki Sumii, Ryosuke Fujita, Susumu Kudo, Effect of shear stress on the migration of hepatic stellate cells, In Vitro Cellular and Developmental Biology - Animal, https://doi.org/10.1007/s11626-017-0202-x, 54, 1, 11-22, 2018.01, When the liver is damaged, hepatic stellate cells (HSCs) can change into an activated, highly migratory state. The migration of HSCs may be affected by shear stress due not only to sinusoidal flow but also by the flow in the space of Disse because this space is filled with blood plasma. In this study, we evaluated the effects of shear stress on HSC migration in a scratch-wound assay with a parallel flow chamber. At regions upstream of the wound area, the migration was inhibited by 0.6 Pa and promoted by 2.0 Pa shear stress, compared to the static condition. The platelet-derived growth factor (PDGF)-BB receptor, PDGFR-β, was expressed in all conditions and the differences were not significant. PDGF increased HSC migration, except at 0.6 Pa shear stress, which was still inhibited. These results indicate that another molecular factor, such as PDGFR-α, may act to inhibit the migration under low shear stress. At regions downstream of the wound area, the migration was smaller under shear stress than under the static condition, although the expression of PDGFR-β was significantly higher. In particular, the migration direction was opposite to the wound area under high shear stress; therefore, migration might be influenced by the intercellular environment. Our results indicate that HSC migration was influenced by shear stress intensity and the intercellular environment..
4. Masataka Arai, Tomoya Shimada, Chihiro Kora, Kazuhiro Nakashima, Toshihiro Sera, Susumu Kudo, Biphasic and directed translocation of protein kinase Cα inside cultured endothelial cells before migration, Biochemistry and Biophysics Reports, https://doi.org/10.1016/j.bbrep.2017.08.003, 12, 91-97, 2017.12, Mechanical wounding of an endothelial monolayer induces an immediate Ca2+ wave. Several hours later, the denuded area is covered by endothelial cells (ECs) that migrate to the wound. This migration process is closely related to protein kinase Cα (PKCα), a Ca2+-dependent protein that translocates from the cytosol to the cell membrane. Because the cells adjacent to the wounded area are the first to migrate into the wound, we investigated whether a mechanical wound immediately induces PKCα translocation in adjacent cells. We monitored Ca2+ dynamics and PKCα translocation simultaneously using fluorescent microscopy. For this simultaneous observation, we used Fura-2–acetoxymethyl ester to visualize Ca2+ and constructed a green fluorescent protein-tagged fusion protein to visualize PKCα. Mechanical wounding of the endothelial monolayer induced an immediate Ca2+ wave in cells adjacent to the wounded cells before their migration. Almost concurrently, PKCα in the neighboring cells translocated to the cell membrane, then accumulated at the periphery near the wounded cell. This report is the first description of this biphasic and directed translocation of PKCα in cells before cell migration. Our results may provide new insights into the directed migration of ECs..
5. Alireza Karimi, Seyed Mohammadali Rahmati, Toshihiro Sera, Susumu Kudo, Mahdi Navidbakhsh, A Combination of Constitutive Damage Model and Artificial Neural Networks to Characterize the Mechanical Properties of the Healthy and Atherosclerotic Human Coronary Arteries, Artificial Organs, https://doi.org/10.1111/aor.12855, 41, 9, E103-E117, 2017.09, It has been indicated that the content and structure of the elastin and collagen of the arterial wall can subject to a significant alteration due to the atherosclerosis. Consequently, a high tissue stiffness, stress, and even damage/rupture are triggered in the arterial wall. Although many studies so far have been conducted to quantify the mechanical properties of the coronary arteries, none of them consider the role of collagen damage of the healthy and atherosclerotic human coronary arterial walls. Recently, a fiber family-based constitutive equation was proposed to capture the anisotropic mechanical response of the healthy and atherosclerotic human coronary arteries via both the histostructural and uniaxial data. In this study, experimental mechanical measurements along with histological data of the healthy and atherosclerotic arterial walls were employed to determine the constitutive damage parameters and remodeling of the collagen fibers. To do this, the preconditioned arterial tissues were excised from human cadavers within 5-h postmortem, and the mean angle of their collagen fibers was precisely determined. Thereafter, a group of quasistatic axial and circumferential loadings were applied to the arterial walls, and the constrained nonlinear minimization method was employed to identify the arterial parameters according to the axial and circumferential extension data. The remodeling of the collagen fibers during the tensile test was also predicted via Artificial Neural Networks algorithm. Regardless of loading direction, the results presented a noteworthy load-bearing capability and stiffness of the atherosclerotic arteries compared to the healthy ones (P < 0.005). Theoretical fiber angles were found to be consistent with the experimental histological data with less than 2 and 5° difference for the healthy and atherosclerotic arterial walls, respectively. The pseudoelastic damage model data were also compared with that of the experimental data, and interestingly, the arterial mechanical behavior for both the primary loading (up to the elastic region) and the discontinuous softening (up to the ultimate stress) was well addressed. The proposed model predicted well the mechanical response of the arterial tissue considering the damage of collagen fibers for both the healthy and atherosclerotic arterial walls..
6. Alireza Karimi, Razaghi Reza, Toshihiro Sera, Susumu Kudo, Mahdi Navidbakhsh, Computing the influences of different Intraocular Pressures on the human eye components using computational fluid-structure interaction model, Technology and Health Care, 25, 285-297, 2017.03.
7. Alireza Karimi, Reza Razaghi, Mahdi Navidbakhsh, Toshihiro Sera, Susumu Kudo, Mechanical properties of the human sclera under various strain rates
Elastic, hyperelastic, and viscoelastic models, Journal of Biomaterials and Tissue Engineering, https://doi.org/10.1166/jbt.2017.1609, 7, 8, 686-695, 2017.01, The sclera is the white outer shell of the eye which its material properties have a key asset for preserving the form of the eye against the exterior and interior musculature and fluctuations forces induce by Intraocular Pressure (IOP). Besides, the biomechanical atmosphere of the head of the optic nerve is profoundly affected by the mechanical properties of the sclera. Computational modeling is a useful way to understand various types of the injuries to the eye, such as trauma. In order to produce reliable numerical results, it is necessary to input precise material properties into the numerical models. However, so far there is a paucity of knowledge about the dissimilarity of the scleral mechanical properties/behaviors under various loading conditions. Therefore, the aim of this study was to evaluate the linear elastic and nonlinear hyperelastic mechanical properties of the human sclera at eight different strain rates. The experimental results revealed a significant role of the strain rate on the elastic modulus and maximum stress in a way that the lowest and highest elastic modulus and stress were observed at the strain rate of 5 and 200 mm/min, respectively. Due to the nonlinear mechanical behavior of the sclera, three different constitutive strain energy density functions examined and their coefficients were calculated thru the linear/nonlinear optimization method. Finally, the agreement of the constitutive data with that of the experimental ones was verified using a FE model of the tensile test. Due to the strain rate dependency of the results, the viscoelastic time-dependentmechanical behavior of the sclera was also assessed through the relaxation Prony-series formulation. Although all these three material models can be used to address the mechanical response of the sclera, according to the objective of a numerical model and its possible applications, each of which can be selected. The outcomes of the concurrent study may have implications not only for understanding the linear elastic and nonlinear hyperelastic mechanical properties of the sclera tissue under various loading rates, but also for knowing the time-dependent viscoelastic mechanical properties of the sclera under the relaxation loading..
8. Alireza Karimi, Seyed Mohammadali Rahmati, Toshihiro Sera, Susumu Kudo, Mahdi Navidbakhsh, A Combination of Constitutive Damage Model and Artificial Neural Networks to Characterize the Mechanical Properties of the Healthy and Atherosclerotic Human Coronary Arteries, Artificial Organs, 1-15, 2017.01.
9. Alireza Karimi, Toshihiro Sera, Susumu Kudo, Mahdi Navidbakhsh, Experimental verification of the healthy and atherosclerotic coronary arteries incompressibility via Digital Image Correlation, Artery Research, 16, 1-7, 2016.09.
10. Tateki Sumii, Yohei Nakano, Takuma Abe, Toshihiro Sera, Kazuhiro Nakashima, Susumu Kudo, Effects of nitric oxide on ammonia decomposition by hepatocytes under shear stress, Journal of Biorheology, in press, 2016.09.
11. Alireza Karimi, Reza Razaghi, Susumu Kudo, Mahdi Navidbakhsh, Dynamic finite element simulation of the human head under impact, loading to compare the application of PVA and EPS as helmet materials, Journal of Advanced Physics,, 5, 3, 214-219, 2016.09.
12. Alireza Karimi, Reza Razaghi, Mahdi Navidbakhsh, Toshihiro Sera, Susumu Kudo, Computing the stresses and deformations of the human eye components due to a high explosive detonation using fluid–structure interaction model, Injury, 47, 5, 1042-1050, 2016.05.
13. Alireza Karimi, Reza Razaghi, Mahdi Navidbakhsh, Toshihiro Sera, Susumu Kudo, Measurement of the mechanical properties of soccer balls using digital image correlation method, Sport Sciences for Health, 12, 1, 69-76, 2016.04.
14. Alireza Karimi, Reza Razaghi, Mahdi Navidbakhsh, Toshihiro Sera, Susumu Kudo, Dynamic finite element simulation of the gunshot injury to the human forehead protected by polyvinyl alcohol sponge, Journal of Materials Science: Materials in Medicine, 27, 74, 1-12, 2016.04.
15. Tateki Sumii, Yohei Nakano, Toshihiro Sera, Takuma Abe, Kazuhiro Nakashima, Susumu Kudo, The Effect of Nitric Oxide on Ammonia Decomposition in Co-cultures of Hepatocytes and Hepatic Stellate Cells, In Vitro Cellular & Developmental Biology - Animal, 1-7, 2016.02.
16. Alireza Karimi, Susumu Kudo, Reza Razaghi, Mahdi Navidbakhsh, Measurement of the mechanical properties of the handball, volleyball, and basketball using DIC method: a combination of experimental, constitutive, and viscoelastic models, Sport Sciences for Health, 11, 3, 295-303, 2015.12.
17. Alireza Karimi, Reza Razaghi, Mahdi Navidbakhsh, Toshihiro Sera, Susumu Kudo, Quantifying the injury of the human eye components due to tennis ball impact using a computational fluid-structure interaction model, Sports Engineering, 1-11, 2015.12.
18. Alireza Karimi, Susumu Kudo, Reza Razaghi, Mahdi Navidbakhsh, A comparative study on the mechanical properties of the healthy and varicose human saphenous vein under uniaxial loading, Journal of Medical Engineering & Technology, 10.3109/03091902.2015.1086030, 39, 8, 490-497, 2015.09.
19. Alireza Karimi, Susumu Kudo, Reza Razaghi, Mahdi Navidbakhsh, A Combination of Experimental and Numerical Analyses to Measure the Compressive Mechanical Properties of Tennis Ball, Biomed. Eng. Appl. Basis Commun., 27, 1550039 -7 pages, 2015.06.
20. Hitoshi Muguruma, Tatsuya Hoshino, Ryosuke Fujita, Takeki Sumii, Susumu Kudo, Adhesion and Alignment of Nonparenchymal Cells onto a Patterned Surface with a Two-Step Plasma Polymerization Process,, Plasma Process. Polym., 12, 8, 746-754, 2015.02.