The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
X C Zhang - One of the best experts on this subject based on the ideXlab platform.
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coherent polarization control of thz waves generated from asymmetrically ionized Gases
Journal of Physics: Conference Series, 2011Co-Authors: Nicholas Karpowicz, X C ZhangAbstract:Unlike polarization control of optical waves, lossless control over the polarization of broadband terahertz waves remained challenging. We recently found that the polarization of terahertz waves generated from Gas Plasma excited by femtosecond fundamental pulse (ω) and its second harmonic (2ω) could be coherently controlled by changing the relative phase between the ω and 2ω pulses. In particular, when the ω and 2ω pulses are both circularly polarized (or close to it), the photo-excited electrons exhibit different trajectories as the relative phase between the two optical pulses changes, and subsequently terahertz polarization angle can be controlled arbitrarily through the relative phase while the intensity of the emitted terahertz wave is kept constant. This new finding may enable fast terahertz wave modulation and coherent control of nonlinear responses excited by intense terahertz waves with controllable polarization.
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terahertz wave air photonics terahertz wave generation and detection with laser induced Gas Plasma
IEEE Journal of Selected Topics in Quantum Electronics, 2011Co-Authors: Jianming Dai, Jingle Liu, X C ZhangAbstract:Ultrabroadband, intense terahertz (THz) waves can be generated and detected using Gaseous media as both the THz wave emitter and sensor, with a bandwidth covering the entire “THz gap” and well beyond. We review our most recent experimental and theoretical progress in THz generation, detection, and manipulation in laser-induced Gas Plasma. In the generation part, emphasis will be on the case with two-color excitation of Gaseous media. Potential applications of these novel THz generation and detection techniques will also be discussed and proof-of-principle experiments are demonstrated.
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broadband terahertz wave remote sensing using coherent manipulation of fluorescence from asymmetrically ionized Gases
Nature Photonics, 2010Co-Authors: S L Chin, X C ZhangAbstract:An ‘all-optical’ technique is proposed that can be used to detect broadband terahertz waves by coherently manipulating fluorescence emission from a Gas Plasma. This technique can be used to measure terahertz pulses at a distance of 10 m with unlimited directionality, even in the presence of water vapour absorption.
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terahertz radiation enhanced emission of fluorescence from Gas Plasma
Physical Review Letters, 2009Co-Authors: Jingle Liu, X C ZhangAbstract:We report the study of femtosecond laser-induced air Plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of Gas molecules or ions. We demonstrate that the temporal waveform of the THz field could be retrieved from the transient enhanced fluorescence, making omnidirectional, coherent detection available for THz time-domain spectroscopy.
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coherent polarization control of terahertz waves generated from two color laser induced Gas Plasma
Physical Review Letters, 2009Co-Authors: Jianming Dai, Nicholas Karpowicz, X C ZhangAbstract:Electrons ionized from an atom or molecule by circularly or elliptically polarized femtosecond ! and 2! pulses exhibit different trajectory orientations as the relative phase between the two pulses changes. Macroscopically, the polarization of the terahertz wave emitted during the ionization process was found to be coherently controllable through the optical phase. This new finding can be completely reproduced by numerical simulation and may enable fast terahertz wave modulation and coherent control of nonlinear responses excited by intense terahertz waves with controllable polarization.
Jan Feijen - One of the best experts on this subject based on the ideXlab platform.
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blood compatibility of surfaces with immobilized albumin heparin conjugate and effect of endothelial cell seeding on platelet adhesion
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Endothelial cell (EC) seeding significantly improves the blood compatibility of artificial surfaces. Although a coating consisting of albumin and heparin (alb-hep) is a suitable substrate for seeded ECs, binding of ECs to the substrate further improves when small amounts of fibronectin are present in the alb-hep coating. Alb-hep conjugate was immobilized on carbon dioxide Gas Plasma-treated polystyrene (PS-CO2), thereby significantly increasing the recalcification time of blood Plasma exposed to this surface. Furthermore, surface-immobilized alb-hep conjugate inhibited exogenous thrombin. Heparin activity was reduced by adding fibronectin on top of a monolayer of alb-hep conjugate, but not by simultaneous coating of fibronectin and alb-hep conjugate. Coating of PS-CO2 with alb-hep conjugate significantly decreased contact activation (FXII activation). The number of platelets deposited from blood Plasma on PS-CO2 coated with alb-hep conjugate was twice as high as on PS-CO2 coated with albumin. Addition of fibronectin to alb-hep conjugate-coated PS-CO2 had no significant effect on the number of adhered platelets. Seeding of the substrates with ECs significantly reduced the number of adhered platelets under stationary conditions. Platelets deposited onto endothelialized surfaces were primarily found on endothelial cell edges, and sparingly on areas between ECs. In conclusion, alb-hep conjugate-coated surfaces display anticoagulant activity. ECs adhering to and proliferating on this coating significantly decrease the number of platelets which adhere to the surface. Therefore, alb-hep conjugate-coated surfaces form a suitable substrate for seeding of ECs in low density. Although application of fibronectin on top of the coating decreases the anticoagulant activity to some extent, it might be useful in view of the improved adherence of ECs to the coating.
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proliferation of endothelial cells on surface immobilized albumin heparin conjugate loaded with basic fibroblast growth factor
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prostheses. Immobilization of basic fibroblast growth factor (bFGF) to substrates used to coat or fill porous prostheses may enhance the formation of a confluent monolayer of ECs. Human umbilical vein endothelial cells (HUVECs) were grown on bFGF-loaded albumin-heparin conjugate bound to CO2 Gas-Plasma-treated polystyrene. In the order of 2-3 ng/cm2 bFGF had to be immobilized to form a confluent monolayer of HUVECs. The most prominent effect of surface-immobilized bFGF was stimulation of the proliferation shortly after seeding, resulting within 3 days in confluent cell monolayers with high density. In contrast, in cultures with 0.3 ng/mL bFGF in the medium instead of bFGF bound to the surface, it took almost a week before the cell layers reached confluency. Binding of bFGF to heparin and the biological activity of bFGF towards ECs were not influenced by the (radio-)labeling of bFGF with iodine. However, only a minor part of the bFGF used in this study displayed heparin affinity. Furthermore, degradation and multimerization of labeled bFGF in time occurred when the growth factor was stored at 20°-37°C. This limits the use of labeled bFGF to short-term (hours) experiments. In conclusion, bFGF loading of vascular graft surfaces through complexation of bFGF with a heparin-containing matrix probably will lead to more rapid formation of a confluent monolayer of ECs on graft surfaces upon seeding of the cells.
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adherence and proliferation of endothelial cells on surface immobilized albumin heparin conjugate
Tissue Engineering, 1998Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, Johannes G A Terlingen, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Small-diameter vascular grafts rapidly fail after implantation, due to occlusion caused by thrombosis. This problem cannot be overcome using medication. A promising improvement of graft patency is the seeding of endothelial cells (EC) on the luminal surface of the vascular graft. Conjugates of albumin and heparin, which were developed to obtain nonthrombogenic coatings, could form an ideal coating for vascular grafts. Besides presenting anticoagulant function, heparin will bind proteins with cell adhesive properties, thus facilitating adherence of EC to the graft surface. EC were able to grow to confluency on CO2 Gas Plasma–treated polystyrene (PS-CO2) coated with albumin-heparin conjugate. CO2 Gas Plasma treatment resulted in the introduction of functional groups at the surface (e.g., hydroxyl, aldehyde, carboxylic acid, and epoxide groups). Addition of albumin-heparin conjugate to the functionalized surface in an aqueous solution with pH 8.2 yielded a stable monolayer of covalently bound conjugate. The number of cells adhering and proliferating on this surface was comparable to the number of cells on fibronectin-coated PS-CO2. However, the structure and size of EC proliferating on surface-immobilized albumin-heparin was more irregular. Long-term adherence might be improved by adding fibronectin to the albumin-heparin surface, either as a mixture with albumin-heparin or in a separate incubation step.
Nicole M Scharenborg - One of the best experts on this subject based on the ideXlab platform.
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blood compatibility of surfaces with immobilized albumin heparin conjugate and effect of endothelial cell seeding on platelet adhesion
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Endothelial cell (EC) seeding significantly improves the blood compatibility of artificial surfaces. Although a coating consisting of albumin and heparin (alb-hep) is a suitable substrate for seeded ECs, binding of ECs to the substrate further improves when small amounts of fibronectin are present in the alb-hep coating. Alb-hep conjugate was immobilized on carbon dioxide Gas Plasma-treated polystyrene (PS-CO2), thereby significantly increasing the recalcification time of blood Plasma exposed to this surface. Furthermore, surface-immobilized alb-hep conjugate inhibited exogenous thrombin. Heparin activity was reduced by adding fibronectin on top of a monolayer of alb-hep conjugate, but not by simultaneous coating of fibronectin and alb-hep conjugate. Coating of PS-CO2 with alb-hep conjugate significantly decreased contact activation (FXII activation). The number of platelets deposited from blood Plasma on PS-CO2 coated with alb-hep conjugate was twice as high as on PS-CO2 coated with albumin. Addition of fibronectin to alb-hep conjugate-coated PS-CO2 had no significant effect on the number of adhered platelets. Seeding of the substrates with ECs significantly reduced the number of adhered platelets under stationary conditions. Platelets deposited onto endothelialized surfaces were primarily found on endothelial cell edges, and sparingly on areas between ECs. In conclusion, alb-hep conjugate-coated surfaces display anticoagulant activity. ECs adhering to and proliferating on this coating significantly decrease the number of platelets which adhere to the surface. Therefore, alb-hep conjugate-coated surfaces form a suitable substrate for seeding of ECs in low density. Although application of fibronectin on top of the coating decreases the anticoagulant activity to some extent, it might be useful in view of the improved adherence of ECs to the coating.
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proliferation of endothelial cells on surface immobilized albumin heparin conjugate loaded with basic fibroblast growth factor
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prostheses. Immobilization of basic fibroblast growth factor (bFGF) to substrates used to coat or fill porous prostheses may enhance the formation of a confluent monolayer of ECs. Human umbilical vein endothelial cells (HUVECs) were grown on bFGF-loaded albumin-heparin conjugate bound to CO2 Gas-Plasma-treated polystyrene. In the order of 2-3 ng/cm2 bFGF had to be immobilized to form a confluent monolayer of HUVECs. The most prominent effect of surface-immobilized bFGF was stimulation of the proliferation shortly after seeding, resulting within 3 days in confluent cell monolayers with high density. In contrast, in cultures with 0.3 ng/mL bFGF in the medium instead of bFGF bound to the surface, it took almost a week before the cell layers reached confluency. Binding of bFGF to heparin and the biological activity of bFGF towards ECs were not influenced by the (radio-)labeling of bFGF with iodine. However, only a minor part of the bFGF used in this study displayed heparin affinity. Furthermore, degradation and multimerization of labeled bFGF in time occurred when the growth factor was stored at 20°-37°C. This limits the use of labeled bFGF to short-term (hours) experiments. In conclusion, bFGF loading of vascular graft surfaces through complexation of bFGF with a heparin-containing matrix probably will lead to more rapid formation of a confluent monolayer of ECs on graft surfaces upon seeding of the cells.
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adherence and proliferation of endothelial cells on surface immobilized albumin heparin conjugate
Tissue Engineering, 1998Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, Johannes G A Terlingen, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Small-diameter vascular grafts rapidly fail after implantation, due to occlusion caused by thrombosis. This problem cannot be overcome using medication. A promising improvement of graft patency is the seeding of endothelial cells (EC) on the luminal surface of the vascular graft. Conjugates of albumin and heparin, which were developed to obtain nonthrombogenic coatings, could form an ideal coating for vascular grafts. Besides presenting anticoagulant function, heparin will bind proteins with cell adhesive properties, thus facilitating adherence of EC to the graft surface. EC were able to grow to confluency on CO2 Gas Plasma–treated polystyrene (PS-CO2) coated with albumin-heparin conjugate. CO2 Gas Plasma treatment resulted in the introduction of functional groups at the surface (e.g., hydroxyl, aldehyde, carboxylic acid, and epoxide groups). Addition of albumin-heparin conjugate to the functionalized surface in an aqueous solution with pH 8.2 yielded a stable monolayer of covalently bound conjugate. The number of cells adhering and proliferating on this surface was comparable to the number of cells on fibronectin-coated PS-CO2. However, the structure and size of EC proliferating on surface-immobilized albumin-heparin was more irregular. Long-term adherence might be improved by adding fibronectin to the albumin-heparin surface, either as a mixture with albumin-heparin or in a separate incubation step.
G H M Engbers - One of the best experts on this subject based on the ideXlab platform.
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blood compatibility of surfaces with immobilized albumin heparin conjugate and effect of endothelial cell seeding on platelet adhesion
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Endothelial cell (EC) seeding significantly improves the blood compatibility of artificial surfaces. Although a coating consisting of albumin and heparin (alb-hep) is a suitable substrate for seeded ECs, binding of ECs to the substrate further improves when small amounts of fibronectin are present in the alb-hep coating. Alb-hep conjugate was immobilized on carbon dioxide Gas Plasma-treated polystyrene (PS-CO2), thereby significantly increasing the recalcification time of blood Plasma exposed to this surface. Furthermore, surface-immobilized alb-hep conjugate inhibited exogenous thrombin. Heparin activity was reduced by adding fibronectin on top of a monolayer of alb-hep conjugate, but not by simultaneous coating of fibronectin and alb-hep conjugate. Coating of PS-CO2 with alb-hep conjugate significantly decreased contact activation (FXII activation). The number of platelets deposited from blood Plasma on PS-CO2 coated with alb-hep conjugate was twice as high as on PS-CO2 coated with albumin. Addition of fibronectin to alb-hep conjugate-coated PS-CO2 had no significant effect on the number of adhered platelets. Seeding of the substrates with ECs significantly reduced the number of adhered platelets under stationary conditions. Platelets deposited onto endothelialized surfaces were primarily found on endothelial cell edges, and sparingly on areas between ECs. In conclusion, alb-hep conjugate-coated surfaces display anticoagulant activity. ECs adhering to and proliferating on this coating significantly decrease the number of platelets which adhere to the surface. Therefore, alb-hep conjugate-coated surfaces form a suitable substrate for seeding of ECs in low density. Although application of fibronectin on top of the coating decreases the anticoagulant activity to some extent, it might be useful in view of the improved adherence of ECs to the coating.
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proliferation of endothelial cells on surface immobilized albumin heparin conjugate loaded with basic fibroblast growth factor
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prostheses. Immobilization of basic fibroblast growth factor (bFGF) to substrates used to coat or fill porous prostheses may enhance the formation of a confluent monolayer of ECs. Human umbilical vein endothelial cells (HUVECs) were grown on bFGF-loaded albumin-heparin conjugate bound to CO2 Gas-Plasma-treated polystyrene. In the order of 2-3 ng/cm2 bFGF had to be immobilized to form a confluent monolayer of HUVECs. The most prominent effect of surface-immobilized bFGF was stimulation of the proliferation shortly after seeding, resulting within 3 days in confluent cell monolayers with high density. In contrast, in cultures with 0.3 ng/mL bFGF in the medium instead of bFGF bound to the surface, it took almost a week before the cell layers reached confluency. Binding of bFGF to heparin and the biological activity of bFGF towards ECs were not influenced by the (radio-)labeling of bFGF with iodine. However, only a minor part of the bFGF used in this study displayed heparin affinity. Furthermore, degradation and multimerization of labeled bFGF in time occurred when the growth factor was stored at 20°-37°C. This limits the use of labeled bFGF to short-term (hours) experiments. In conclusion, bFGF loading of vascular graft surfaces through complexation of bFGF with a heparin-containing matrix probably will lead to more rapid formation of a confluent monolayer of ECs on graft surfaces upon seeding of the cells.
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adherence and proliferation of endothelial cells on surface immobilized albumin heparin conjugate
Tissue Engineering, 1998Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, Johannes G A Terlingen, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Small-diameter vascular grafts rapidly fail after implantation, due to occlusion caused by thrombosis. This problem cannot be overcome using medication. A promising improvement of graft patency is the seeding of endothelial cells (EC) on the luminal surface of the vascular graft. Conjugates of albumin and heparin, which were developed to obtain nonthrombogenic coatings, could form an ideal coating for vascular grafts. Besides presenting anticoagulant function, heparin will bind proteins with cell adhesive properties, thus facilitating adherence of EC to the graft surface. EC were able to grow to confluency on CO2 Gas Plasma–treated polystyrene (PS-CO2) coated with albumin-heparin conjugate. CO2 Gas Plasma treatment resulted in the introduction of functional groups at the surface (e.g., hydroxyl, aldehyde, carboxylic acid, and epoxide groups). Addition of albumin-heparin conjugate to the functionalized surface in an aqueous solution with pH 8.2 yielded a stable monolayer of covalently bound conjugate. The number of cells adhering and proliferating on this surface was comparable to the number of cells on fibronectin-coated PS-CO2. However, the structure and size of EC proliferating on surface-immobilized albumin-heparin was more irregular. Long-term adherence might be improved by adding fibronectin to the albumin-heparin surface, either as a mixture with albumin-heparin or in a separate incubation step.
Willem G Van Aken - One of the best experts on this subject based on the ideXlab platform.
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blood compatibility of surfaces with immobilized albumin heparin conjugate and effect of endothelial cell seeding on platelet adhesion
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Endothelial cell (EC) seeding significantly improves the blood compatibility of artificial surfaces. Although a coating consisting of albumin and heparin (alb-hep) is a suitable substrate for seeded ECs, binding of ECs to the substrate further improves when small amounts of fibronectin are present in the alb-hep coating. Alb-hep conjugate was immobilized on carbon dioxide Gas Plasma-treated polystyrene (PS-CO2), thereby significantly increasing the recalcification time of blood Plasma exposed to this surface. Furthermore, surface-immobilized alb-hep conjugate inhibited exogenous thrombin. Heparin activity was reduced by adding fibronectin on top of a monolayer of alb-hep conjugate, but not by simultaneous coating of fibronectin and alb-hep conjugate. Coating of PS-CO2 with alb-hep conjugate significantly decreased contact activation (FXII activation). The number of platelets deposited from blood Plasma on PS-CO2 coated with alb-hep conjugate was twice as high as on PS-CO2 coated with albumin. Addition of fibronectin to alb-hep conjugate-coated PS-CO2 had no significant effect on the number of adhered platelets. Seeding of the substrates with ECs significantly reduced the number of adhered platelets under stationary conditions. Platelets deposited onto endothelialized surfaces were primarily found on endothelial cell edges, and sparingly on areas between ECs. In conclusion, alb-hep conjugate-coated surfaces display anticoagulant activity. ECs adhering to and proliferating on this coating significantly decrease the number of platelets which adhere to the surface. Therefore, alb-hep conjugate-coated surfaces form a suitable substrate for seeding of ECs in low density. Although application of fibronectin on top of the coating decreases the anticoagulant activity to some extent, it might be useful in view of the improved adherence of ECs to the coating.
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proliferation of endothelial cells on surface immobilized albumin heparin conjugate loaded with basic fibroblast growth factor
Journal of Biomedical Materials Research, 1999Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Seeding of endothelial cells (ECs) on the luminal surface of small-diameter vascular grafts is a promising method to avoid occlusion of these prostheses. Immobilization of basic fibroblast growth factor (bFGF) to substrates used to coat or fill porous prostheses may enhance the formation of a confluent monolayer of ECs. Human umbilical vein endothelial cells (HUVECs) were grown on bFGF-loaded albumin-heparin conjugate bound to CO2 Gas-Plasma-treated polystyrene. In the order of 2-3 ng/cm2 bFGF had to be immobilized to form a confluent monolayer of HUVECs. The most prominent effect of surface-immobilized bFGF was stimulation of the proliferation shortly after seeding, resulting within 3 days in confluent cell monolayers with high density. In contrast, in cultures with 0.3 ng/mL bFGF in the medium instead of bFGF bound to the surface, it took almost a week before the cell layers reached confluency. Binding of bFGF to heparin and the biological activity of bFGF towards ECs were not influenced by the (radio-)labeling of bFGF with iodine. However, only a minor part of the bFGF used in this study displayed heparin affinity. Furthermore, degradation and multimerization of labeled bFGF in time occurred when the growth factor was stored at 20°-37°C. This limits the use of labeled bFGF to short-term (hours) experiments. In conclusion, bFGF loading of vascular graft surfaces through complexation of bFGF with a heparin-containing matrix probably will lead to more rapid formation of a confluent monolayer of ECs on graft surfaces upon seeding of the cells.
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adherence and proliferation of endothelial cells on surface immobilized albumin heparin conjugate
Tissue Engineering, 1998Co-Authors: Nicole M Scharenborg, Andre A Poot, G H M Engbers, Johannes G A Terlingen, T Beugeling, Willem G Van Aken, Jan FeijenAbstract:Small-diameter vascular grafts rapidly fail after implantation, due to occlusion caused by thrombosis. This problem cannot be overcome using medication. A promising improvement of graft patency is the seeding of endothelial cells (EC) on the luminal surface of the vascular graft. Conjugates of albumin and heparin, which were developed to obtain nonthrombogenic coatings, could form an ideal coating for vascular grafts. Besides presenting anticoagulant function, heparin will bind proteins with cell adhesive properties, thus facilitating adherence of EC to the graft surface. EC were able to grow to confluency on CO2 Gas Plasma–treated polystyrene (PS-CO2) coated with albumin-heparin conjugate. CO2 Gas Plasma treatment resulted in the introduction of functional groups at the surface (e.g., hydroxyl, aldehyde, carboxylic acid, and epoxide groups). Addition of albumin-heparin conjugate to the functionalized surface in an aqueous solution with pH 8.2 yielded a stable monolayer of covalently bound conjugate. The number of cells adhering and proliferating on this surface was comparable to the number of cells on fibronectin-coated PS-CO2. However, the structure and size of EC proliferating on surface-immobilized albumin-heparin was more irregular. Long-term adherence might be improved by adding fibronectin to the albumin-heparin surface, either as a mixture with albumin-heparin or in a separate incubation step.
