Nature PortfolioActa Medica Okayama2045-23221312023Comprehensive hemocompatibility analysis on the application of diamond-like carbon to ePTFE artificial vascular prosthesis8386ENTakashiGoyamaDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesYasuhiroFujiiDepartment of Cardiovascular Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesGenyaMuraokaDepartment of Cardiovascular Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical SciencesTatsuyukiNakataniInstitute of Frontier Science and Technology, Okayama University of ScienceDaikiOusakaDepartment of Pharmacology, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesYuichiImaiInstitute of Frontier Science and Technology, Okayama University of ScienceNoriakiKuwadaDepartment of Cardiovascular Surgery, Kawasaki Medical HospitalTatsunoriTsujiDepartment of Cardiovascular Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesTakayukiShukuDepartment of Civil Engineering, Okayama University Graduate School of Environmental and Life ScienceHaruhito A.UchidaDepartment of Chronic Kidney Disease and Cardiovascular Disease, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesMasahiroNishiboriDepartment of Translational Research and Drug Development, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesSusumuOozawaDivision of Medical Safety Management, Safety Management Facility, Okayama University HospitalShingoKasaharaDepartment of Cardiovascular Surgery, Okayama University Faculty of Medicine, Dentistry and Pharmaceutical SciencesThe aim of this study was to obtain comprehensive data regarding the hemocompatibility of diamond-like carbon (DLC)-coated expanded polytetrafluoroethylene (ePTFE). DLC increased the hydrophilicity and smoothened the surface and fibrillar structure, respectively, of the ePTFE. DLC-coated ePTFE had more albumin and fibrinogen adsorption and less platelet adhesion than uncoated ePTFE. There were scarce red cell attachments in in vitro human and in vivo animal (rat and swine) whole blood contact tests in both DLC-coated and uncoated ePTFE. DLC-coated ePTFE had a similar but marginally thicker band movement than uncoated-ePTFE with SDS-PAGE after human whole blood contact test. In addition, survival studies of aortic graft replacement in rats (1.5 mm graft) and arteriovenous shunt in goats (4 mm graft) were performed to compare the patency and clot formation between DLC-coated and uncoated ePTFE grafts. Comparable patency was observed in both animal models. However, clots were observed in the luminal surface of the patent 1.5 mm DLC-coated ePTFE grafts, but not in that of uncoated ePTFE grafts. In conclusions, hemocompatibility of DLC-coated ePTFE was high and comparable to that of uncoated ePTFE. However, it failed to improve the hemocompatibility of 1.5 mm ePTFE graft probably because increased fibrinogen adsorption canceled the other beneficial effects of DLC.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama003808066122021Reliability-based design for earth-fill dams against severe natural disaster events271282ENShin-ichiNishimuraGraduate School of Environmental and Life Science, Okayama UniversityToshifumiShibataGraduate School of Environmental and Life Science, Okayama UniversityTakayukiShukuGraduate School of Environmental and Life Science, Okayama UniversityThe maintenance of geotechnical structures, such as earth-fill dams, is required as a countermeasure against severe natural disasters, particularly earthquakes and heavy rains. The reliability-based analysis introduced here is in response to the recent demand for low-cost improvements.First, a statistical model of N values was determined from Swedish weight sounding (SWS) tests to present the spatial variability of the soil strength. Then, a reliability-based analysis of embankments was conducted by considering the variability of the internal friction angle derived from N value, and the seismic hazard for the Nankai Trough. The next step was to evaluate the probability of the overflow of earth-fills during heavy rains. The rainfall intensity was considered as a probabilistic parameter, and the various rainfall patterns were tested by the proposed method. Finally, the total risk due to both earthquakes and heavy rains was evaluated for an earth-fill site. As a result, the possibility for the practical use of the proposed method in making plans for the maintenance of deteriorated earth-fill dams was verified.No potential conflict of interest relevant to this article was reported.岡山大学環境理工学部Acta Medica Okayama1341909925120203次元計測を利用した効率的な3次元有限要素モデル化法の提案14ENMinoruKANESHIGEShin-ichiNISHIMURAToshifumiSHIBATATakayukiSHUKU10.18926/fest/58060 In this decade, 3-dimensional topographic survey has been developed by using the UAV as like drones. With the technique, the complete topographies of the geo-structures can be measured. Although the accurate shapes of the geo-structures can be obtained, the numerical methods as like the finite element method is are not related to the 3-dimensional survey directly. In this research, the finite mesh modelling technique with use of the 3-D topographic survey is developed. The models of the earth-fill embankments formed from measured 3-D data are introduced as the examples.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama0045-78253502019An iterative Bayesian filtering framework for fast and automated calibration of DEM models268294ENHongyangChengMulti-Scale Mechanics (MSM), Faculty of Engineering Technology, MESA+, University of TwenteTakayukiShukuGraduate School of Environmental and Life Science, Okayama UniversityKlausThoeniCentre for Geotechnical Science and Engineering, The University of NewcastlePamelaTemponeDivision of Exploration and ProductionStefanLudingMulti-Scale Mechanics (MSM), Faculty of Engineering Technology, MESA+, University of TwenteVanessaMagnanimoMulti-Scale Mechanics (MSM), Faculty of Engineering Technology, MESA+, University of TwenteThe nonlinear, history-dependent macroscopic behavior of a granular material is rooted in the micromechanics between constituent particles and irreversible, plastic deformations reflected by changes in the microstructure. The discrete element method (DEM) can predict the evolution of the microstructure resulting from interparticle interactions. However, micromechanical parameters at contact and particle levels are generally unknown because of the diversity of granular materials with respect to their surfaces, shapes, disorder and anisotropy.
The proposed iterative Bayesian filter consists in recursively updating the posterior distribution of model parameters and iterating the process with new samples drawn from a proposal density in highly probable parameter spaces. Over iterations the proposal density is progressively localized near the posterior modes, which allows automated zooming towards optimal solutions. The Dirichlet process Gaussian mixture is trained with sparse and high dimensional data from the previous iteration to update the proposal density.
As an example, the probability distribution of the micromechanical parameters is estimated, conditioning on the experimentally measured stress–strain behavior of a granular assembly. Four micromechanical parameters, i.e., contact-level Young’s modulus, interparticle friction, rolling stiffness and rolling friction, are chosen as strongly relevant for the macroscopic behavior. The a priori particle configuration is obtained from 3D X-ray computed tomography images. The a posteriori expectation of each micromechanical parameter converges within four iterations, leading to an excellent agreement between the experimental data and the numerical predictions. As new result, the proposed framework provides a deeper understanding of the correlations among micromechanical parameters and between the micro- and macro-parameters/quantities of interest, including their uncertainties. Therefore, the iterative Bayesian filtering framework has a great potential for quantifying parameter uncertainties and their propagation across various scales in granular materials.No potential conflict of interest relevant to this article was reported.Acta Medica Okayama2014Application of the Particle Filter to COHERENS V2 model of Lake Säkylän Pyhäjärvi101107ENAkikoMANOTakayukiSHUKUNo potential conflict of interest relevant to this article was reported.