In the treatment of a peripheral nerve defect, the use of a tissue engineered artificial nerve may offer an alternative to a nerve autograft Three aspects of a tissue engineered artificial nerve were reviewed: Schwann...In the treatment of a peripheral nerve defect, the use of a tissue engineered artificial nerve may offer an alternative to a nerve autograft Three aspects of a tissue engineered artificial nerve were reviewed: Schwann cell culture, the construction of a three dimensional intrinsic framework for the seeding of Schwann cells, and the fabrication of a biodegradable and semipermeable nerve tube Schwann cell cultivation could be simplified using a serum free medium or in vivo degenerated nerve grafts To improve the attachment and alignment of Schwann cells on the three dimensional intrinsic framework, coating the biomaterials with extracellular matrices and application of a rotating culture system were accepted as promising techniques A few biodegradable and semipermeable nerve tubes made from polyglycolic acid, polylactic acid or collagen were available The dimensions and link of growth factors played a role during nerve regeneration? Until now, tissue engineered artificial nerves have been proved to be effective on supporting nerve regeneration However, the results were inferior to nerve autografts in the case of a long nerve defect The embryonic Schwann cell might be a source of cell due to their wide availability and poor antigenicity In addition, incorporation of growth factors into the intrinsic framework or nerve guides may promote the survival of transplanted Schwann cells and subsequently nerve regeneration The suitable biomaterials are yet to be investigated until an optimal result can be展开更多
Many applications of principal component analysis (PCA) can be found in dimensionality reduction. But linear PCA method is not well suitable for nonlinear chemical processes. A new PCA method based on im-proved input ...Many applications of principal component analysis (PCA) can be found in dimensionality reduction. But linear PCA method is not well suitable for nonlinear chemical processes. A new PCA method based on im-proved input training neural network (IT-NN) is proposed for the nonlinear system modelling in this paper. Mo-mentum factor and adaptive learning rate are introduced into learning algorithm to improve the training speed of IT-NN. Contrasting to the auto-associative neural network (ANN), IT-NN has less hidden layers and higher training speed. The effectiveness is illustrated through a comparison of IT-NN with linear PCA and ANN with experiments. Moreover, the IT-NN is combined with RBF neural network (RBF-NN) to model the yields of ethylene and propyl-ene in the naphtha pyrolysis system. From the illustrative example and practical application, IT-NN combined with RBF-NN is an effective method of nonlinear chemical process modelling.展开更多
文摘In the treatment of a peripheral nerve defect, the use of a tissue engineered artificial nerve may offer an alternative to a nerve autograft Three aspects of a tissue engineered artificial nerve were reviewed: Schwann cell culture, the construction of a three dimensional intrinsic framework for the seeding of Schwann cells, and the fabrication of a biodegradable and semipermeable nerve tube Schwann cell cultivation could be simplified using a serum free medium or in vivo degenerated nerve grafts To improve the attachment and alignment of Schwann cells on the three dimensional intrinsic framework, coating the biomaterials with extracellular matrices and application of a rotating culture system were accepted as promising techniques A few biodegradable and semipermeable nerve tubes made from polyglycolic acid, polylactic acid or collagen were available The dimensions and link of growth factors played a role during nerve regeneration? Until now, tissue engineered artificial nerves have been proved to be effective on supporting nerve regeneration However, the results were inferior to nerve autografts in the case of a long nerve defect The embryonic Schwann cell might be a source of cell due to their wide availability and poor antigenicity In addition, incorporation of growth factors into the intrinsic framework or nerve guides may promote the survival of transplanted Schwann cells and subsequently nerve regeneration The suitable biomaterials are yet to be investigated until an optimal result can be
基金Supported by Beijing Municipal Education Commission (No.xk100100435) and the Key Research Project of Science andTechnology from Sinopec (No.E03007).
文摘Many applications of principal component analysis (PCA) can be found in dimensionality reduction. But linear PCA method is not well suitable for nonlinear chemical processes. A new PCA method based on im-proved input training neural network (IT-NN) is proposed for the nonlinear system modelling in this paper. Mo-mentum factor and adaptive learning rate are introduced into learning algorithm to improve the training speed of IT-NN. Contrasting to the auto-associative neural network (ANN), IT-NN has less hidden layers and higher training speed. The effectiveness is illustrated through a comparison of IT-NN with linear PCA and ANN with experiments. Moreover, the IT-NN is combined with RBF neural network (RBF-NN) to model the yields of ethylene and propyl-ene in the naphtha pyrolysis system. From the illustrative example and practical application, IT-NN combined with RBF-NN is an effective method of nonlinear chemical process modelling.
