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Andreas Lendlein - One of the best experts on this subject based on the ideXlab platform.

  • initiation of shape memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Reinhard Mohr, M. Moneke, Karl Kratz, Th Weigel, M Luckagabor, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, Tswitch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(e-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25°C resulted in temporary fixation of the mechanical deformation by 50–60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA·m−1). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

  • Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences, 2006
    Co-Authors: Reinhard Mohr, M. Lucka-gabor, M. Moneke, Thomas Weigel, Karl Kratz, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T(switch). If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(epsilon-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25 degrees C resulted in temporary fixation of the mechanical deformation by 50-60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA x m(-1)). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

Reinhard Mohr - One of the best experts on this subject based on the ideXlab platform.

  • initiation of shape memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Reinhard Mohr, M. Moneke, Karl Kratz, Th Weigel, M Luckagabor, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, Tswitch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(e-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25°C resulted in temporary fixation of the mechanical deformation by 50–60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA·m−1). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

  • Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences, 2006
    Co-Authors: Reinhard Mohr, M. Lucka-gabor, M. Moneke, Thomas Weigel, Karl Kratz, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T(switch). If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(epsilon-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25 degrees C resulted in temporary fixation of the mechanical deformation by 50-60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA x m(-1)). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

C Tomasetto - One of the best experts on this subject based on the ideXlab platform.

  • Matrix metalloproteinase-11/stromelysin-3 exhibits collagenolytic function against collagen VI under normal and malignant conditions
    Oncogene, 2008
    Co-Authors: E R Motrescu, S Blaise, N Etique, N Messaddeq, M-p Chenard, I Stoll, C Tomasetto
    Abstract:

    The substrate of Matrix metalloproteinase 11 (MMP11) remains unknown. We have recently shown that MMP11 is a negative regulator of adipogenesis, able to reduce and even to revert mature adipocyte differentiation. Here, we have used mouse 3T3L1 cells and human U87MG and SaOS cells to show that MMP11 cleaves the native α3 chain of collagen VI, which is an adipocyte-related extracellular Matrix Component. It is known that extracellular proteolytic processing of this chain is required for correct collagen VI folding. Interestingly, MMP11-deficient fat tissue is less cohesive and exhibits collagen VI alteration, dramatic adipocyte plasma and basement membrane abnormalities and lipid leakage. MMP11 is thus required for correct collagen VI folding and therefore for fat tissue cohesion and adipocyte function. Both MMP11 and collagen VI favor tumor progression. Similar spatio-temporal overexpression at the adipocyte–cancer cell interface has been reported for the two proteins. MMP11-dependent collagen VI processing might therefore be expected to occur during malignancy. Accordingly, collagen VI no longer delineates adipocytes located at the invasive front of breast carcinomas. In conclusion, the native α3 chain of collagen VI constitutes a specific MMP11 substrate. This MMP11 collagenolytic activity is functional in fat tissue ontogenesis as well as during cancer invasive steps.

  • Matrix metalloproteinase 11 stromelysin 3 exhibits collagenolytic function against collagen vi under normal and malignant conditions
    Oncogene, 2008
    Co-Authors: E R Motrescu, S Blaise, N Etique, N Messaddeq, M-p Chenard, I Stoll, C Tomasetto
    Abstract:

    The substrate of Matrix metalloproteinase 11 (MMP11) remains unknown. We have recently shown that MMP11 is a negative regulator of adipogenesis, able to reduce and even to revert mature adipocyte differentiation. Here, we have used mouse 3T3L1 cells and human U87MG and SaOS cells to show that MMP11 cleaves the native α3 chain of collagen VI, which is an adipocyte-related extracellular Matrix Component. It is known that extracellular proteolytic processing of this chain is required for correct collagen VI folding. Interestingly, MMP11-deficient fat tissue is less cohesive and exhibits collagen VI alteration, dramatic adipocyte plasma and basement membrane abnormalities and lipid leakage. MMP11 is thus required for correct collagen VI folding and therefore for fat tissue cohesion and adipocyte function. Both MMP11 and collagen VI favor tumor progression. Similar spatio-temporal overexpression at the adipocyte–cancer cell interface has been reported for the two proteins. MMP11-dependent collagen VI processing might therefore be expected to occur during malignancy. Accordingly, collagen VI no longer delineates adipocytes located at the invasive front of breast carcinomas. In conclusion, the native α3 chain of collagen VI constitutes a specific MMP11 substrate. This MMP11 collagenolytic activity is functional in fat tissue ontogenesis as well as during cancer invasive steps.

Karl Kratz - One of the best experts on this subject based on the ideXlab platform.

  • initiation of shape memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Reinhard Mohr, M. Moneke, Karl Kratz, Th Weigel, M Luckagabor, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, Tswitch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(e-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25°C resulted in temporary fixation of the mechanical deformation by 50–60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA·m−1). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

  • Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences, 2006
    Co-Authors: Reinhard Mohr, M. Lucka-gabor, M. Moneke, Thomas Weigel, Karl Kratz, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T(switch). If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(epsilon-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25 degrees C resulted in temporary fixation of the mechanical deformation by 50-60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA x m(-1)). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

M. Moneke - One of the best experts on this subject based on the ideXlab platform.

  • initiation of shape memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences of the United States of America, 2006
    Co-Authors: Reinhard Mohr, M. Moneke, Karl Kratz, Th Weigel, M Luckagabor, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, Tswitch. If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(e-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25°C resulted in temporary fixation of the mechanical deformation by 50–60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA·m−1). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.

  • Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers
    Proceedings of the National Academy of Sciences, 2006
    Co-Authors: Reinhard Mohr, M. Lucka-gabor, M. Moneke, Thomas Weigel, Karl Kratz, Andreas Lendlein
    Abstract:

    In shape-memory polymers, changes in shape are mostly induced by heating, and exceeding a specific switching temperature, T(switch). If polymers cannot be warmed up by heat transfer using a hot liquid or gaseous medium, noncontact triggering will be required. In this article, the magnetically induced shape-memory effect of composites from magnetic nanoparticles and thermoplastic shape-memory polymers is introduced. A polyetherurethane (TFX) and a biodegradable multiblock copolymer (PDC) with poly(p-dioxanone) as hard segment and poly(epsilon-caprolactone) as soft segment were investigated as Matrix Component. Nanoparticles consisting of an iron(III)oxide core in a silica Matrix could be processed into both polymers. A homogeneous particle distribution in TFX could be shown. Compounds have suitable elastic and thermal properties for the shape-memory functionalization. Temporary shapes of TFX compounds were obtained by elongating at increased temperature and subsequent cooling under constant stress. Cold-drawing of PDC compounds at 25 degrees C resulted in temporary fixation of the mechanical deformation by 50-60%. The shape-memory effect of both composite systems could be induced by inductive heating in an alternating magnetic field (f = 258 kHz; H = 30 kA x m(-1)). The maximum temperatures achievable by inductive heating in a specific magnetic field depend on sample geometry and nanoparticle content. Shape recovery rates of composites resulting from magnetic triggering are comparable to those obtained by increasing the environmental temperature.