研究者業績

Tetsuji Tokihiro

  (時弘 哲治)

Profile Information

Affiliation
Faculty of Engineering Department of Mathematical Engineering, Musashino University
Degree
工学博士(Mar, 1986, 東京大学 大学院工学系研究科 物理工学専攻)

Researcher number
10163966
J-GLOBAL ID
202201002240761169
researchmap Member ID
R000034549

Committee Memberships

 2

Papers

 108
  • Kazuma Sakai, Tatsuya Hayashi, Yusuke Sakai, Jun Mada, Kazuo Tonami, Yasunobu Uchijima, Hiroki Kurihara, Tetsuji Tokihiro
    Scientific Reports, 13(1), Nov 23, 2023  Peer-reviewed
    Abstract We introduce a three-dimensional mathematical model for the dynamics of vascular endothelial cells during sprouting angiogenesis. Angiogenesis is the biological process by which new blood vessels form from existing ones. It has been the subject of numerous theoretical models. These models have successfully replicated various aspects of angiogenesis. Recent studies using particle-based models have highlighted the significant influence of cell shape on network formation, with elongated cells contributing to the formation of branching structures. While most mathematical models are two-dimensional, we aim to investigate whether ellipsoids also form branch-like structures and how their shape affects the pattern. In our model, the shape of a vascular endothelial cell is represented as a spheroid, and a discrete dynamical system is constructed based on the simple assumption of two-body interactions. Numerical simulations demonstrate that our model reproduces the patterns of elongation and branching observed in the early stages of angiogenesis. We show that the pattern formation of the cell population is strongly dependent on the cell shape. Finally, we demonstrate that our current mathematical model reproduces the cell behaviours, specifically cell-mixing, observed in sprouts.
  • Kazuo Tonami, Tatsuya Hayashi, Yasunobu Uchijima, Masahiro Kanai, Fumitaka Yura, Jun Mada, Kei Sugahara, Yukiko Kurihara, Yuri Kominami, Toshiyuki Ushijima, Naoko Takubo, Xiaoxiao Liu, Hideto Tozawa, Yoshimitsu Kanai, Tetsuji Tokihiro, Hiroki Kurihara
    iScience, 26(7) 107051-107051, Jun, 2023  Peer-reviewed
  • Tatsuya Hayashi, Fumitaka Yura, Jun Mada, Hiroki Kurihara, Tetsuji Tokihiro
    Journal of Theoretical Biology, 555 111300-111300, Dec, 2022  Peer-reviewed
  • Jun Mada, Tetsuji Tokihiro
    JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS, 39(1) 351-384, Jan, 2022  Peer-reviewed
    We discuss the characteristics of the patterns of the vascular networks in a mathematical model for angiogenesis. Based on recent in vitro experiments, this mathematical model assumes that the elongation and bifurcation of blood vessels during angiogenesis are determined by the density of endothelial cells at the tip of the vascular network, and describes the dynamical changes in vascular network formation using a system of simultaneous ordinary differential equations. The pattern of formation strongly depends on the supply rate of endothelial cells by cell division, the branching angle, and also on the connectivity of vessels. By introducing reconnection of blood vessels, the statistical distribution of the size of islands in the network is discussed with respect to bifurcation angles and elongation factor distributions. The characteristics of the obtained patterns are analysed using multifractal dimension and other techniques.
  • Yuri Kominami, Tatsuya Hayashi, Tetsuji Tokihiro, Hideki Ushio
    FOOD CHEMISTRY: MOLECULAR SCIENCES, 3, Dec, 2021  Peer-reviewed
    Recent studies have suggested that thaw-aging can improve sensory attributes of freeze-thawed meat. Acceleration of proteolysis is expected to promote tenderisation and improve taste; however, the details of protein degradation, including substrate proteins and cleavage sites, remain unclear. Here, we report a time course overview of the peptidome of beef short plates during thaw-aging. The accelerated degradation of key proteins for meat tenderisation, such as troponin T and desmin, was confirmed. Additionally, 11 cleavage sites in troponin T related to taste-active peptide generation were identified. Terminome analysis showed that the contribution of each protease varies depending on the substrate proteins and the thaw-aging period. Based on our results; proteases, not only calpains, but also others contributed to the degradation of myofibrillar proteins. The techniques employed indicate that meat proteolysis during thaw-aging is not constant but dynamic.

Misc.

 2
  • 岩尾慎介, 時弘哲治
    日本物理学会講演概要集, 62(2), 2007  
  • Hirokazu Tsunetsugu, Takeo Fujiwara, Kazuo Ueda, Tetsuji Tokihiro
    Journal of the Physical Society of Japan, 55(5) 1420-1423, 1986  
    We find a systematic procedure constructing the 2D and 3D “periodic” Penrose tilings, which tend to the infinite Penrose tilings. The electronic states in the 2d Penrose tiling are studied by using this sequence. We observe that the spectral measure is singular continuous in the limit of the infinite size. Most of eigenstates are critical, i.e. neither extended nor localized. © 1986, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

Books and Other Publications

 5

Presentations

 14

Research Projects

 30