The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform

A Soum - One of the best experts on this subject based on the ideXlab platform.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 2 in vitro cytocompatibility analysis and in vivo ed1 cell response of a new nerve guide
    Biomaterials, 2001
    Co-Authors: Thierry Fabre, Michele Schappacher, A Soum, Reine Bareille, B Dupuy, J Bertrandbarat, Charles Baquey
    Abstract:

    Future surgical strategies to restore neurological function in peripheral nerve loss may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. Random coPolymers of trimethylene carbonate and caprolactone (P(CL-TMC), 50 : 50) have been synthesized by ring opening Polymerization using rare earth alkoxides as initiator. Their potential use as nerve guide repairs has been assessed through indirect and direct in vitro biocompatibility tests and in vivo soft tissue response to ED1 subclass macrophages. In vitro, we exposed monolayers of human skin "broblasts and an established continuous cell line (Hela) to liquid extracts (either pure or diluted in the culture medium) of CL-TMC coPolymer including positive (phenol) and negative controls. Then, colorimetric assays (Neutral red and MTT) were performed. The extracts of CL-TMC induced no signi"cant cytotoxic e!ect. We also exposed in vitro Schwann cells to pieces of P(CL-TMC) and P(LA-GA) coPolymers. We evaluated cell attachment at 1 and 3 h by measuring the activity of the lysosomal enzyme (N-acetyl--hexosaminidase) and cell proliferation at 1, 3, 6 and 9 days by measuring the cell metabolic activity (MTT assay). Values for attachment slightly decreased between 1 and 3 h but were signi"cantly higher than on agars (negative control). Cells plated on CL-TMC showed a rate of proliferation comparable with that of normalized controls and higher than on PGA-PLA at day 9. Finally, we evaluated in vivo the soft tissue response after implantation of cylindrical tubes of P(CL-TMC) and P(LA-GA) coPolymers with an immunohistochemistry staining procedure for the newly recruited ED1 macrophages. An image analysis system automatically measured the optical density of labelled positive ED1 cells at 9, 21 and 60 days after implantation. CL-TMC coPolymer showed a mild soft tissue reaction with no adverse chronic in#ammatory reaction. These data allowed us to consider this conduit as a potential e!ective substitute in nerve repair. 2001 Elsevier Science Ltd. All rights reserved.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 1 preparation of a new nerve guide through controlled random coPolymerization using rare earth catalysts
    Biomaterials, 2001
    Co-Authors: Michele Schappacher, Thierry Fabre, A F Mingotaud, A Soum
    Abstract:

    Random coPolymers of trimethylene carbonate and e-caprolactone have been synthesized through ring-opening Polymerization using rare earth alkoxides as initiator. The structure of the coPolymers has been characterized by 1H and 13C NMR. Their thermal behaviour, their permeability to liquid and their mechanical properties have also been evaluated. These coPolymers have been used to process a new nerve guide.

Yanjin Guan - One of the best experts on this subject based on the ideXlab platform.

  • research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes respectively with steam heating and electric heating
    Materials & Design, 2010
    Co-Authors: Guilong Wang, Guoqun Zhao, Huiping Li, Yanjin Guan
    Abstract:

    The dynamic mold temperature control system is the key of rapid heat cycle molding (RHCM) technology because it significantly affects the stability of the process, productivity and the quality of the final Polymer Part. For this reason, the approaches and techniques for dynamic mold temperature control were discussed in this study and two different dynamic mold temperature control methods, respectively, with steam heating and electric heating were found to be very feasible in mass production. The methods and principles of mold design for the two RHCM technologies were also discussed and then several different kinds of mold structures were designed. By constructing the corresponding thermal response analytical models for these RHCM molds, the temperature responses of the molding systems in the heating and cooling process of RHCM were simulated and studied. The effects of the mold design parameters such as the insulation layer between mold plate and mold inert, and mold material, on thermal response efficiency and temperature uniformity of the two RHCM processes were analyzed based on the simulation results. The results show that the insulation layer can increase the upper limit temperature of RHCM with steam heating and improve the heating speed of RHCM with electric heating. It can also greatly decrease the energy consumption of the two RHCM processes. The heating efficiency of RHCM with steam heating can be effectively improved by increasing the thermal conductivity of the cavity/core material, while the situation is diametrically opposite for RHCM with electric heating. Therefore, we acquired an optimized mold design principle and method for RHCM with steam heating and electric heating, respectively. Finally, a new electric heating mold with a cooling plate was proposed to enhance the cooling efficiency. The thermal response of this new electric heating mold was also simulated. The simulation results show that the cooling plate can significantly improve the cooling and heating efficiency.

Michele Schappacher - One of the best experts on this subject based on the ideXlab platform.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 2 in vitro cytocompatibility analysis and in vivo ed1 cell response of a new nerve guide
    Biomaterials, 2001
    Co-Authors: Thierry Fabre, Michele Schappacher, A Soum, Reine Bareille, B Dupuy, J Bertrandbarat, Charles Baquey
    Abstract:

    Future surgical strategies to restore neurological function in peripheral nerve loss may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. Random coPolymers of trimethylene carbonate and caprolactone (P(CL-TMC), 50 : 50) have been synthesized by ring opening Polymerization using rare earth alkoxides as initiator. Their potential use as nerve guide repairs has been assessed through indirect and direct in vitro biocompatibility tests and in vivo soft tissue response to ED1 subclass macrophages. In vitro, we exposed monolayers of human skin "broblasts and an established continuous cell line (Hela) to liquid extracts (either pure or diluted in the culture medium) of CL-TMC coPolymer including positive (phenol) and negative controls. Then, colorimetric assays (Neutral red and MTT) were performed. The extracts of CL-TMC induced no signi"cant cytotoxic e!ect. We also exposed in vitro Schwann cells to pieces of P(CL-TMC) and P(LA-GA) coPolymers. We evaluated cell attachment at 1 and 3 h by measuring the activity of the lysosomal enzyme (N-acetyl--hexosaminidase) and cell proliferation at 1, 3, 6 and 9 days by measuring the cell metabolic activity (MTT assay). Values for attachment slightly decreased between 1 and 3 h but were signi"cantly higher than on agars (negative control). Cells plated on CL-TMC showed a rate of proliferation comparable with that of normalized controls and higher than on PGA-PLA at day 9. Finally, we evaluated in vivo the soft tissue response after implantation of cylindrical tubes of P(CL-TMC) and P(LA-GA) coPolymers with an immunohistochemistry staining procedure for the newly recruited ED1 macrophages. An image analysis system automatically measured the optical density of labelled positive ED1 cells at 9, 21 and 60 days after implantation. CL-TMC coPolymer showed a mild soft tissue reaction with no adverse chronic in#ammatory reaction. These data allowed us to consider this conduit as a potential e!ective substitute in nerve repair. 2001 Elsevier Science Ltd. All rights reserved.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 1 preparation of a new nerve guide through controlled random coPolymerization using rare earth catalysts
    Biomaterials, 2001
    Co-Authors: Michele Schappacher, Thierry Fabre, A F Mingotaud, A Soum
    Abstract:

    Random coPolymers of trimethylene carbonate and e-caprolactone have been synthesized through ring-opening Polymerization using rare earth alkoxides as initiator. The structure of the coPolymers has been characterized by 1H and 13C NMR. Their thermal behaviour, their permeability to liquid and their mechanical properties have also been evaluated. These coPolymers have been used to process a new nerve guide.

Thierry Fabre - One of the best experts on this subject based on the ideXlab platform.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 2 in vitro cytocompatibility analysis and in vivo ed1 cell response of a new nerve guide
    Biomaterials, 2001
    Co-Authors: Thierry Fabre, Michele Schappacher, A Soum, Reine Bareille, B Dupuy, J Bertrandbarat, Charles Baquey
    Abstract:

    Future surgical strategies to restore neurological function in peripheral nerve loss may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. Random coPolymers of trimethylene carbonate and caprolactone (P(CL-TMC), 50 : 50) have been synthesized by ring opening Polymerization using rare earth alkoxides as initiator. Their potential use as nerve guide repairs has been assessed through indirect and direct in vitro biocompatibility tests and in vivo soft tissue response to ED1 subclass macrophages. In vitro, we exposed monolayers of human skin "broblasts and an established continuous cell line (Hela) to liquid extracts (either pure or diluted in the culture medium) of CL-TMC coPolymer including positive (phenol) and negative controls. Then, colorimetric assays (Neutral red and MTT) were performed. The extracts of CL-TMC induced no signi"cant cytotoxic e!ect. We also exposed in vitro Schwann cells to pieces of P(CL-TMC) and P(LA-GA) coPolymers. We evaluated cell attachment at 1 and 3 h by measuring the activity of the lysosomal enzyme (N-acetyl--hexosaminidase) and cell proliferation at 1, 3, 6 and 9 days by measuring the cell metabolic activity (MTT assay). Values for attachment slightly decreased between 1 and 3 h but were signi"cantly higher than on agars (negative control). Cells plated on CL-TMC showed a rate of proliferation comparable with that of normalized controls and higher than on PGA-PLA at day 9. Finally, we evaluated in vivo the soft tissue response after implantation of cylindrical tubes of P(CL-TMC) and P(LA-GA) coPolymers with an immunohistochemistry staining procedure for the newly recruited ED1 macrophages. An image analysis system automatically measured the optical density of labelled positive ED1 cells at 9, 21 and 60 days after implantation. CL-TMC coPolymer showed a mild soft tissue reaction with no adverse chronic in#ammatory reaction. These data allowed us to consider this conduit as a potential e!ective substitute in nerve repair. 2001 Elsevier Science Ltd. All rights reserved.

  • study of a trimethylenecarbonate co e caprolactone Polymer Part 1 preparation of a new nerve guide through controlled random coPolymerization using rare earth catalysts
    Biomaterials, 2001
    Co-Authors: Michele Schappacher, Thierry Fabre, A F Mingotaud, A Soum
    Abstract:

    Random coPolymers of trimethylene carbonate and e-caprolactone have been synthesized through ring-opening Polymerization using rare earth alkoxides as initiator. The structure of the coPolymers has been characterized by 1H and 13C NMR. Their thermal behaviour, their permeability to liquid and their mechanical properties have also been evaluated. These coPolymers have been used to process a new nerve guide.

Tatiana Budtova - One of the best experts on this subject based on the ideXlab platform.

  • Lignocellulosic fiber breakage in a molten Polymer. Part 1. Qualitative analysis using rheo-optical observations
    Composites Part A: Applied Science and Manufacturing, 2016
    Co-Authors: Romain Castellani, Erika Di Giuseppe, Johnny Beaugrand, Sandrine Dobosz, Françoise Berzin, Bruno Vergnes, Tatiana Budtova
    Abstract:

    Understanding how lignocellulosic fibers break during compounding and shaping processes (e.g. extrusion, injection) is of the greatest importance for mastering fiber size evolution and thus predicting composite mechanical properties. In this first paper of a series devoted to this topic, rheo-optical experiments were used for a direct observation of fibers’ behavior when sheared in a molten thermoplastic matrix. Fibers from four vegetal species were studied: hemp, flax, sisal and miscanthus. While possessing different morphological, composition and mechanical characteristics, these fibers also display different preponderant breakage mechanisms. We were able to distinguish fibers breakage (i) in a fragile way (flax and sisal), (ii) by fatigue, i.e. cumulated strain (hemp), or (iii) by peeling (miscanthus). Each fiber type is qualitatively classified according to these categories and correlations with lignin and hemicellulose contents are discussed.