The Experts below are selected from a list of 11505 Experts worldwide ranked by ideXlab platform
Patrick Hansheinrich Warnke - One of the best experts on this subject based on the ideXlab platform.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic Nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable Nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic Nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable Nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
Xungai Wang - One of the best experts on this subject based on the ideXlab platform.
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enhanced mechanical energy harvesting using needleless electrospun poly vinylidene fluoride Nanofibre webs
Energy and Environmental Science, 2013Co-Authors: Jian Fang, Hongxia Wang, Xungai WangAbstract:Randomly oriented poly(vinylidene fluoride) (PVDF) Nanofibre webs prepared by a needleless electrospinning technique were used as an active layer for making mechanical-to-electrical energy harvest devices. With increasing the applied voltage in the electrospinning process, a higher β crystal phase was formed in the resulting PVDF Nanofibres, leading to enhanced mechanical-to-electrical energy conversion of the devices. The power generated by the Nanofibre devices was able to drive a miniature Peltier cooler, which may be useful for the development of mechanically driven cooling textile. In addition, the needleless electrospinning also showed great potential in the production of Nanofibres on a large scale.
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electrospun Nanofibre toughened carbon epoxy composites effects of polyetherketone cardo pek c Nanofibre diameter and interlayer thickness
Composites Science and Technology, 2010Co-Authors: Jin Zhang, Tong Lin, Xungai WangAbstract:Polyetherketone cardo (PEK-C) Nanofibres were produced by an electrospinning technique and directly deposited on carbon fabric to improve the interlaminar fracture toughness of carbon/epoxy composites. The influences of Nanofibre diameter and interlayer thickness on the Mode I delamination fracture toughness, flexure property and thermal mechanical properties of the resultant composites were examined. Considerably enhanced interlaminar fracture toughness has been achieved by interleaving PEK-C Nanofibres with the weight loading as low as 0.4% (based on weight of the composite). Finer Nanofibres result in more stable crack propagation and better mechanical performance under flexure loading. Composites modified by finer Nanofibres maintained the glass transition temperature (Tg) of the cured resin. Increasing Nanofibre interlayer thickness improved the fracture toughness but compromised the flexure performance. The Tg of the cured resin deteriorated after the thickness increased to a certain extent.
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In vivo wound healing and antibacterial performances of electrospun Nanofibre membranes
Journal of biomedical materials research. Part A, 2010Co-Authors: Xin Liu, Jian Fang, Tong Lin, Gang Yao, Hongqiong Zhao, Michael Dodson, Xungai WangAbstract:In this work, Nanofibre membranes have been produced from polyvinyl alcohol (PVA), polycaprolactone (PCL), polyacrylonitrile (PAN), poly (vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), and polymer blend of PAN and polyurethane (PEU) using an electrospinning technique, and wound healing performance of the as-spun Nanofibre membranes was examined in vivo using female Sprague-Dawley rats. To understand the nutrition effect, a wool protein was coated on PVA and PCL Nanofibres and incorporated into PVA Nanofibres via coelectrospinning of a PVA solution containing the wool protein. Silver nanoparticles were also applied to PVA Nanofibres to improve antibacterial activity. It was found that the wound healing performance is mainly influenced by the porosity, air permeability, and surface wettability of the Nanofibre membranes. A Nanofibre membrane with good hydrophilicity and high porosity considerably facilitates the healing of wound especially at the early healing stage. However, the fiber diameter and antibacterial activity have little effect on the wound healing efficiency. As pores in Nanofibre membranes are typically smaller than that of conventional cotton gauze, the Nanofibre membrane should be able to decontaminate and prevent exogenous infections via sieve effect. This work provides basic understanding of material structure-property relationship for further design of efficient Nanofibre-based wound dressing materials.
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Electrospun Nanofibre toughened carbon/epoxy composites: Effects of polyetherketone cardo (PEK-C) Nanofibre diameter and interlayer thickness
Composites Science and Technology, 2010Co-Authors: Jin Zhang, Tong Lin, Xungai WangAbstract:Polyetherketone cardo (PEK-C) Nanofibres were produced by an electrospinning technique and directly deposited on carbon fabric to improve the interlaminar fracture toughness of carbon/epoxy composites. The influences of Nanofibre diameter and interlayer thickness on the Mode I delamination fracture toughness, flexure property and thermal mechanical properties of the resultant composites were examined. Considerably enhanced interlaminar fracture toughness has been achieved by interleaving PEK-C Nanofibres with the weight loading as low as 0.4% (based on weight of the composite). Finer Nanofibres result in more stable crack propagation and better mechanical performance under flexure loading. Composites modified by finer Nanofibres maintained the glass transition temperature (Tg) of the cured resin. Increasing Nanofibre interlayer thickness improved the fracture toughness but compromised the flexure performance. The Tg of the cured resin deteriorated after the thickness increased to a certain extent.
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carbon nanotubes reinforced electrospun polymer Nanofibres
Nanofibers, 2010Co-Authors: Minoo Naebe, Tong Lin, Xungai WangAbstract:With the rapid development in nanoscience and nanotechnology, there is an ever increasing demand for polymer fibres of diameters down to a nanometre scale having multiple functionalities. Electrospinning, as a simple and efficient Nanofibre-making technology, has been used to produce polymer Nanofibres for diverse applications. Electrospun Nanofibres based on polymer/carbon nanotube (CNT) composites are very attractive multifunctional nanomaterials because they combine the remarkable mechanical and electronic properties of CNTs and the confinement-enhanced CNTs alignment within the Nanofibre structure, which could greatly improve the fibre mechanical, electrical and thermal properties. In this chapter, we summarise recent research progress on electrospun CNTs/polymer Nanofibres, with an emphasis on fibre mechanical properties and structure-property attributes. Outlook towards the challenge and future directions in this field is also presented.
Mohammad A Alamein - One of the best experts on this subject based on the ideXlab platform.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic Nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable Nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
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polymeric nanofibrous substrates stimulate pluripotent stem cells to form three dimensional multilayered patty like spheroids in feeder free culture and maintain their pluripotency
Journal of Tissue Engineering and Regenerative Medicine, 2015Co-Authors: Mohammad A Alamein, Ernst J Wolvetang, Dmitry A Ovchinnikov, Sebastien Robert Stephens, Katherine Anne Sanders, Patrick Hansheinrich WarnkeAbstract:Expansion of pluripotent stem cells in defined media devoid of animal-derived feeder cells to generate multilayered three-dimensional (3D) bulk preparations or spheroids, rather than two-dimensional (2D) monolayers, is advantageous for many regenerative, biological or disease-modelling studies. Here we show that electrospun polymer matrices comprised of Nanofibres that mimic the architecture of the natural fibrous extracellular matrix allow for feeder-free expansion of pluripotent human induced pluripotent stem cells (IPSCs) and human embryonic stem cells (HESCs) into multilayered 3D 'patty-like' spheroid structures in defined xeno-free culture medium. The observation that IPSCs and HESCs readily revert to 2D growth in the absence of the synthetic Nanofibre membranes suggests that this 3D expansion behaviour is mediated by the physical microenvironment and artificial niche provided by the Nanofibres only. Importantly, we could show that such 3D growth as patties maintained the pluripotency of cells as long as they were kept on Nanofibres. The generation of complex multilayered 3D structures consisting of only pluripotent cells on biodegradable Nanofibre matrices of the desired shape and size will enable both industrial-scale expansion and intricate organ–tissue engineering applications with human pluripotent stem cells, where simultaneous coupling of differentiation pathways of all germ layers from one stem cell source may be required for organ formation.
Ravi Kumar - One of the best experts on this subject based on the ideXlab platform.
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multi level cascaded electromagnetically induced transparency in cold atoms using an optical Nanofibre interface
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Sile Nic ChormaicAbstract:Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical Nanofibres (ONFs) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical Nanofibre to interface cold 87Rb atoms. Intense evanescent fields can be achieved at ultralow probe (780 nm) and coupling (776 nm) powers when the beams propagate through the Nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical Nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-Nanofibre system for quantum information. We also demonstrate all-optical-switching in the all-fibred system using the obtained EIT effect.
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multi level cascaded electromagnetically induced transparency in cold atoms using an optical Nanofibre interface
arXiv: Atomic Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Sile Nic ChormaicAbstract:Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical Nanofibres (ONF) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical Nanofibre to interface cold $^{87}$Rb atoms through the intense evanescent fields that can be achieved at ultralow probe and coupling powers. Both the probe (at 780 nm) and the coupling (at 776 nm) beams propagate through the Nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical Nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-Nanofibre system for quantum information. We also demonstrate all-optical-switching in the all fibred system using the obtained EIT effect.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical Nanofibre
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to sub-wavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical Nanofibre into a magneto-optical trap for 87Rb atoms. The Nanofibre, with a waist diameter of ∼700 nm, supports both the fundamental and first group of higher order modes (HOMs) and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the Nanofibre waist is larger if HOMs are also included. In particular, the signal from HOMs appears to be about six times larger than that obtained for the fundamental mode. Absorption of on-resonance, HOM probe light by the laser-cooled atoms is also observed. These advances should facilitate the realization of atom trapping schemes based on HOM interference.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical nanofiber
arXiv: Atomic Physics, 2013Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to subwavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical Nanofibre into a magneto-optical trap for $^{87}$Rb atoms. The Nanofibre, with a waist diameter of $\sim$700 nm, supports both the fundamental and first group of higher order modes and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the Nanofibre waist is larger ($\sim$6 times) when higher order guided modes are considered as compared to the fundamental mode. Absorption of on-resonance, higher order mode probe light by the laser-cooled atoms is also observed. These advances should facilitate the realisation of atom trapping schemes based on higher order mode interference.
Sile Nic Chormaic - One of the best experts on this subject based on the ideXlab platform.
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multi level cascaded electromagnetically induced transparency in cold atoms using an optical Nanofibre interface
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Sile Nic ChormaicAbstract:Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical Nanofibres (ONFs) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical Nanofibre to interface cold 87Rb atoms. Intense evanescent fields can be achieved at ultralow probe (780 nm) and coupling (776 nm) powers when the beams propagate through the Nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical Nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-Nanofibre system for quantum information. We also demonstrate all-optical-switching in the all-fibred system using the obtained EIT effect.
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multi level cascaded electromagnetically induced transparency in cold atoms using an optical Nanofibre interface
arXiv: Atomic Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Sile Nic ChormaicAbstract:Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical Nanofibres (ONF) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical Nanofibre to interface cold $^{87}$Rb atoms through the intense evanescent fields that can be achieved at ultralow probe and coupling powers. Both the probe (at 780 nm) and the coupling (at 776 nm) beams propagate through the Nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical Nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-Nanofibre system for quantum information. We also demonstrate all-optical-switching in the all fibred system using the obtained EIT effect.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical Nanofibre
New Journal of Physics, 2015Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to sub-wavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical Nanofibre into a magneto-optical trap for 87Rb atoms. The Nanofibre, with a waist diameter of ∼700 nm, supports both the fundamental and first group of higher order modes (HOMs) and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the Nanofibre waist is larger if HOMs are also included. In particular, the signal from HOMs appears to be about six times larger than that obtained for the fundamental mode. Absorption of on-resonance, HOM probe light by the laser-cooled atoms is also observed. These advances should facilitate the realization of atom trapping schemes based on HOM interference.
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interaction of laser cooled 87 rb atoms with higher order modes of an optical nanofiber
arXiv: Atomic Physics, 2013Co-Authors: Ravi Kumar, Vandna Gokhroo, Aili Maimaiti, Kieran Deasy, Mary C Frawley, C F Phelan, Sile Nic ChormaicAbstract:Optical Nanofibres are used to confine light to subwavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near Nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical Nanofibre into a magneto-optical trap for $^{87}$Rb atoms. The Nanofibre, with a waist diameter of $\sim$700 nm, supports both the fundamental and first group of higher order modes and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the Nanofibre waist is larger ($\sim$6 times) when higher order guided modes are considered as compared to the fundamental mode. Absorption of on-resonance, higher order mode probe light by the laser-cooled atoms is also observed. These advances should facilitate the realisation of atom trapping schemes based on higher order mode interference.
