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Tissue-engineered grafts using a scaffold can be used in treating periodontal disease; however, previous scaffolds for the cultivations of the periodontal ligament cells have been structurally incompatible with the morphological requirements of human periodontal tissue. Here, we describe a self-organized honeycomb-patterned film (honeycomb film) that acted as an appropriate scaffold for periodontal tissue regeneration. The honeycomb films were prepared from biodegradable poly(e-caprolactone) with highly regular three-dimensional micropatterned surface topography by casting a polymer solution of water-immiscible solvent under humid conditions. To evaluate its performance in activating the proliferation and organizing of cells, we have demonstrated specific behaviors of the cultured periodontal ligament cells on the self-organized honeycomb structures in vitro. Fibroblast-like cells derived from the periodontal ligament of extracted human molar teeth were cultivated on three types of honeycomb films with 5-, 10-, and 15-µm pore sizes for 4 h to 42 d. Morphological observation of the cultured tissues at 4—72 h revealed that the pseudopodiums of cell bodies were attached to the pillars in the honeycomb structure. A certain number of cells shifted their cell bodies into the honeycomb structural lumen through the oscula of 10- and 15-µm pores. After 28 and 42 d, the cells were observed to have formed multiple layers; further, each cell had penetrated through the 10- and 15-µm pores in the honeycomb film. The morphological examination of the honeycomb film along with the pillar structures revealed that the scaffold was clusteringly arrayed with interconnected structures, remarkably enhanced proliferation, and extension of the cultured cells. We consider that the film can be applied in periodontal therapy for use as a scaffold for periodontal tissue regeneration.

In this paper, a new analytical method for unsteady-state problems of heat conduction in anisotropic materials is presented. Under the assumption that the form of the heat conduction equation in anisotropic materials is invariant under a congruence matrix transformation, the equation of heat conduction can be transformed to an equation of the same form as that for the isotropic case. For this matrix transformation, the temperature gradient and heat flux must satisfy the continuity coditions at a boundary between two different media. This method is applicable to the treatment of thermal resistance of composite slabs, the determination of the Green function for the three-dimensional equation of heat conduction in an anisotropic conductor, and the analysis of temperature distribution in the composite regions of infinite anisotropic heat-conducting solids.

We propose a new method of measuring the principal thermal conductivity of a two-dimensional anisotropic heat conductor using a steady heat source and sink. The theory of this new thermal conductivity measurement is based on congruent matrix transformation from nonuniform space of an anisotropic heat conductor to the uniform space of an isotropic one. When we introduce the hypothesis of symmetry in the heat conduction law, it leads to an equivalent relation of the thermal conductivity tensor between the anisotropic tensor Λμ and the uniform space tensor Λν. This new measuring method can provide the two principal thermal conductivities λ1, 2 and the principal rotation angle φ from the temperature detecting axis. We have measured the temperature dependence of two principal thermal conductivities λ1, 2 and the principal rotation angle φ of Y1Ba2Cu3O7-y. Anomalies of the two principal thermal conductivities and the principal rotation angle are clearly observed at the superconductive transition temperature Tc.