Collagen is a protein material with intriguing mechanical properties - it is highly elastic, shows large fracture strength and plays a crucial role in making Nature's structural materials tough. Collagen based tissues consist of collagen fibrils, each of which is composed out of a staggered array of ultra-long tropocollagen molecules extending to several hundred nanometers. Albeit the macroscopic properties of collagen based tissues have been studied extensively, less is known about the nanomechanical properties of tropocollagen molecules and collagen fibrils, their elementary building blocks. In particular, the relationship between molecular properties and tissue properties remains a scarcely explored aspect of the science of collagen materials. Results of molecular multi-scale modeling of the nanomechanical properties of the large-strain deformation regime of collagen fibrils under varying cross-link densities are reported in this paper. The results confirm the significance of cross-links in collagen fibrils in improving its mechanical strength. Further, it is found that cross-links influence the nature of its large-deformation and fracture behavior. Cross-link deficient collagen fibrils show a highly dissipative deformation behavior with large yield regimes. Increasing cross-link densities lead to stronger fibrils that display an increasingly brittle deformation character. The simulation results are compared with recent nanomechanical experiments at the scale of tropocollagen molecules and collagen fibrils.

http://web.mit.edu/mbuehler/www/papers/article-collagen-XL.pdf

Nanomechanics of collagen fibrils under varying cross-link densities: atomistic and continuum studies.

Influence of the laser intensity and spot size on the desorption of molecules and ions in matrix-assisted laser desorption/ionization with a uniform beam profile

https://cyberleninka.org/article/n/1224480.pdf

Membrane electrolysis—History, current status and perspective

Pectins functionalized biomaterials; a new viable approach for biomedical applications: A review.

Bounds are here derived for the effective bulk modulus in heterogeneous media, denoted by k*, using the two standard variational principles of elasticity. As trial functions for the stress and strain fields we use perturbation expansions that have been modified by the inclusion of a set of multiplicative constants. The first order perturbation effect is explicitly calculated and bounds for k* are derived in terms of the correlation functions (/(0)k'(i)lc'(s)) and ([fc'(r)A/(s)/|u(0)]) where n' and k' are the fluctuating parts of the shear modulus n and the bulk modulus, fc, respectively. Explicit calculations are given for two phase media when fi'(x) = 0 and when the media are symmetric in the two phases. Results are also included for the dielectric problem when the media are composed of two symmetric phases.

/pdf/use-of-classical-variational-principles-to-determine-bounds-jgdydychku.pdf

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Papers

Journal of Applied physics,Vol.33 : 1962年に発表されたレオロジー関連の論文

Journal of Chemical Physics, Vol. 36-37 : 1962年に発表されたレオロジー関連の論文

Journal of Polymer Science, Vol. 57-62

Journal of Applied Polymer Science, Vol.6 : 1962年に発表されたレオロジー関連の論文

Die Makromolekulare Chemie, Bd. 58 : 1962年に発表されたレオロジー関連の論文

隆 加藤