ABSTRACT
In this paper, we propose a new time-shared twin memristor crossbar for pattern-recognition applications. By sharing two memristor arrays at different time, the number of memristor arrays can be reduced by half, saving the crossbar area by half, too. To implement the time-shared twin memristor crossbar, we also propose CMOS time-shared subtractor circuit, in this paper. The operation of the time-shared twin memristor crossbar is verified using 3 × 3 memristor array which is made of aluminum film and carbon fiber. Here, the crossbar array is programmed to store three different patterns. When we apply three different input vectors to the array, we can verify that the input vectors are well recognized by the proposed crossbar. Moreover, the proposed crossbar is tested for the recognition of complicated gray-scale images. Here, 10 images with 32 × 32 pixels are applied to the proposed crossbar. The simulation result verifies that the input images are recognized well by the proposed crossbar, even though the noise level of each image is varied from -10 to +10 dB.
ABSTRACT
In tissue engineering and wound-healing applications, dermal substitutes are used to provide fibroblasts with the mechanical support for their growth and then to facilitate the skin formation. In this study, three-dimensional porous poly(lactic-co-glycolic acid) (PLGA) 65/35 scaffolds were prepared and then the composites of the scaffolds and human fetal dermal fibroblasts were fabricated as a tissue-engineered dermal substitute. The function and tissue compatibility of the artificial dermal substitute were evaluated at the levels of gene expression (by RT-PCR) and protein expression (total collagen quantities), as well as by histological and immunohistochemical analysis. The PCR products indicated that the mRNA of type-I collagen, mainly secreted by the fibroblasts onto the PLGA scaffolds, was clearly expressed after 4 weeks. The amount of total collagen synthesized from the cells was shown to increase gradually during the initial culture period and slightly decreased afterwards. After 8 weeks of culture, the fibroblasts were well attached and migrated entirely throughout the pores of the PLGA scaffold with normal function. Furthermore, the positively stained type-I collagen was intensively detected throughout the pores. These results suggest that the function and tissue compatibility may be important criteria in evaluating an artificial tissue-engineered skin.
