liu liu | Tunghai University (original) (raw)
Papers by liu liu
Journal of Biological Chemistry, 2002
The human herpesvirus 8 (HHV8, also called Kaposi's sarcoma-associated herpesvirus) has been link... more The human herpesvirus 8 (HHV8, also called Kaposi's sarcoma-associated herpesvirus) has been linked to Kaposi's sarcoma and primary effusion lymphoma (PEL) in immunocompromised individuals. We demonstrate that PEL cell lines have a constitutively active NF-B pathway, which is associated with persistent phosphorylation of IB␣. To elucidate the mechanism of NF-B activation in PEL cell lines, we have investigated the role of viral FLICE inhibitory protein (vFLIP) in this process. We report that stable expression of HHV8 vFLIP in a variety of cell lines is associated with persistent NF-B activation caused by constitutive phosphorylation of IB␣. HHV8 vFLIP gets recruited to a ϳ700-kDa IB kinase (IKK) complex and physically associates with IKK␣, IKK, NEMO/IKK␥, and RIP. HHV8 vFLIP is incapable of activating NF-B in cells deficient in NEMO/ IKK␥, thereby suggesting an essential role of an intact IKK complex in this process. Our results suggest that HHV8 vFLIP might contribute to the persistent NF-B activation observed in PEL cells by associating with and stimulating the activity of the cellular IKK complex.
Optics Communications, 2006
Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polariton... more Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polaritons are proposed and their characteristics are analyzed numerically using a finite-difference time-domain method. It is shown that these devices can have transverse size smaller than the incident wavelength and can then be regarded as true subwavelength photonic elements. The ultra-compact characteristic of these devices can be utilized as a basis of next generation of integrated photonic circuits. Furthermore, calculations also show that these devices behave differently from their traditional all-dielectric counterparts. For the proposed optical directional coupler, the phase difference between the two output ports will no longer be 90°even when the two ports have the same power outputs.
Optics Express, 2005
A novel surface plasmon waveguide structure is proposed for highly integrated planar lightwave ci... more A novel surface plasmon waveguide structure is proposed for highly integrated planar lightwave circuits. By etching a small trench through a metallic thin film on a silica substrate, a guided mode with highly confined light fields is realized. The mode properties of the proposed structure are studied. The necessity of using a polymer upper-cladding is discussed. The coupling between two closely positioned waveguides and a 90 o bending are also studied numerically. Sharp bending and high integration can be realized with the present surface plasmon waveguide. The proposed structure is easy to fabricate as compared with some other types of surface plasmon waveguides for high integration.
Optics Communications, 2006
Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polariton... more Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polaritons are proposed and their characteristics are analyzed numerically using a finite-difference time-domain method. It is shown that these devices can have transverse size smaller than the incident wavelength and can then be regarded as true subwavelength photonic elements. The ultra-compact characteristic of these devices can be utilized as a basis of next generation of integrated photonic circuits. Furthermore, calculations also show that these devices behave differently from their traditional all-dielectric counterparts. For the proposed optical directional coupler, the phase difference between the two output ports will no longer be 90°even when the two ports have the same power outputs.
Journal of Biomedical Materials Research, 1999
Heparin is a potent anticoagulant which can be immobilized on biomaterial surfaces to increase th... more Heparin is a potent anticoagulant which can be immobilized on biomaterial surfaces to increase their hemocompatability. In the present work, we have electrochemically synthesized composites comprising heparin and the electrically conducting polymer polypyrrole. The incorporation and exposure of heparin were controlled by varying key conditions of polymer synthesis (i.e., applied current and synthesis time). The resulting composite polymers were electroactive after synthesis and the amount of heparin exposed in the polymer could be increased (up to threefold) by switching the polymers from their oxidized to reduced states. Polymer reduction was achieved by either application of negative potentials (-0.4 to -0.7 V for 90 s) or exposure to aqueous reductant (0.1M sodium dithionite for 30 min). Heparin-polypyrrole composites remained stable after autoclaving, displaying no significant loss of electroactivity, and had a shelf life of at least 2 years postautoclaving. Finally, the composites were found to be excellent substrates for the growth of human endothelial cells.
Advanced Functional Materials, 2002
Low voltage electromechanical actuators are attractive for a range of potential applications and ... more Low voltage electromechanical actuators are attractive for a range of potential applications and may be suitable replace-ment materials for high voltage/low strain piezoelectric actua-tors. A range of polymer and carbon nanotube materials has been reported to give acceptable ...
Neuron, 2004
Rapid-onset dystonia-parkinsonism (RDP, DYT12) is a distinctive autosomal-dominant movement disor... more Rapid-onset dystonia-parkinsonism (RDP, DYT12) is a distinctive autosomal-dominant movement disorder with variable expressivity and reduced penetrance characterized by abrupt onset of dystonia, usually accompanied by signs of parkinsonism. The sudden onset of symptoms over hours to a few weeks, often associated with physical or emotional stress, suggests a trigger initiating a nervous system insult resulting in permanent neurologic disability. We report the finding of six missense mutations in the gene for the Na+/K+-ATPase α3 subunit (ATP1A3) in seven unrelated families with RDP. Functional studies and structural analysis of the protein suggest that these mutations impair enzyme activity or stability. This finding implicates the Na+/K+ pump, a crucial protein responsible for the electrochemical gradient across the cell membrane, in dystonia and parkinsonism.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Journal of Biological Chemistry, 2002
The human herpesvirus 8 (HHV8, also called Kaposi's sarcoma-associated herpesvirus) has been link... more The human herpesvirus 8 (HHV8, also called Kaposi's sarcoma-associated herpesvirus) has been linked to Kaposi's sarcoma and primary effusion lymphoma (PEL) in immunocompromised individuals. We demonstrate that PEL cell lines have a constitutively active NF-B pathway, which is associated with persistent phosphorylation of IB␣. To elucidate the mechanism of NF-B activation in PEL cell lines, we have investigated the role of viral FLICE inhibitory protein (vFLIP) in this process. We report that stable expression of HHV8 vFLIP in a variety of cell lines is associated with persistent NF-B activation caused by constitutive phosphorylation of IB␣. HHV8 vFLIP gets recruited to a ϳ700-kDa IB kinase (IKK) complex and physically associates with IKK␣, IKK, NEMO/IKK␥, and RIP. HHV8 vFLIP is incapable of activating NF-B in cells deficient in NEMO/ IKK␥, thereby suggesting an essential role of an intact IKK complex in this process. Our results suggest that HHV8 vFLIP might contribute to the persistent NF-B activation observed in PEL cells by associating with and stimulating the activity of the cellular IKK complex.
Optics Communications, 2006
Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polariton... more Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polaritons are proposed and their characteristics are analyzed numerically using a finite-difference time-domain method. It is shown that these devices can have transverse size smaller than the incident wavelength and can then be regarded as true subwavelength photonic elements. The ultra-compact characteristic of these devices can be utilized as a basis of next generation of integrated photonic circuits. Furthermore, calculations also show that these devices behave differently from their traditional all-dielectric counterparts. For the proposed optical directional coupler, the phase difference between the two output ports will no longer be 90°even when the two ports have the same power outputs.
Optics Express, 2005
A novel surface plasmon waveguide structure is proposed for highly integrated planar lightwave ci... more A novel surface plasmon waveguide structure is proposed for highly integrated planar lightwave circuits. By etching a small trench through a metallic thin film on a silica substrate, a guided mode with highly confined light fields is realized. The mode properties of the proposed structure are studied. The necessity of using a polymer upper-cladding is discussed. The coupling between two closely positioned waveguides and a 90 o bending are also studied numerically. Sharp bending and high integration can be realized with the present surface plasmon waveguide. The proposed structure is easy to fabricate as compared with some other types of surface plasmon waveguides for high integration.
Optics Communications, 2006
Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polariton... more Optical directional couplers and Mach-Zehnder interferometers employing surface plasmon polaritons are proposed and their characteristics are analyzed numerically using a finite-difference time-domain method. It is shown that these devices can have transverse size smaller than the incident wavelength and can then be regarded as true subwavelength photonic elements. The ultra-compact characteristic of these devices can be utilized as a basis of next generation of integrated photonic circuits. Furthermore, calculations also show that these devices behave differently from their traditional all-dielectric counterparts. For the proposed optical directional coupler, the phase difference between the two output ports will no longer be 90°even when the two ports have the same power outputs.
Journal of Biomedical Materials Research, 1999
Heparin is a potent anticoagulant which can be immobilized on biomaterial surfaces to increase th... more Heparin is a potent anticoagulant which can be immobilized on biomaterial surfaces to increase their hemocompatability. In the present work, we have electrochemically synthesized composites comprising heparin and the electrically conducting polymer polypyrrole. The incorporation and exposure of heparin were controlled by varying key conditions of polymer synthesis (i.e., applied current and synthesis time). The resulting composite polymers were electroactive after synthesis and the amount of heparin exposed in the polymer could be increased (up to threefold) by switching the polymers from their oxidized to reduced states. Polymer reduction was achieved by either application of negative potentials (-0.4 to -0.7 V for 90 s) or exposure to aqueous reductant (0.1M sodium dithionite for 30 min). Heparin-polypyrrole composites remained stable after autoclaving, displaying no significant loss of electroactivity, and had a shelf life of at least 2 years postautoclaving. Finally, the composites were found to be excellent substrates for the growth of human endothelial cells.
Advanced Functional Materials, 2002
Low voltage electromechanical actuators are attractive for a range of potential applications and ... more Low voltage electromechanical actuators are attractive for a range of potential applications and may be suitable replace-ment materials for high voltage/low strain piezoelectric actua-tors. A range of polymer and carbon nanotube materials has been reported to give acceptable ...
Neuron, 2004
Rapid-onset dystonia-parkinsonism (RDP, DYT12) is a distinctive autosomal-dominant movement disor... more Rapid-onset dystonia-parkinsonism (RDP, DYT12) is a distinctive autosomal-dominant movement disorder with variable expressivity and reduced penetrance characterized by abrupt onset of dystonia, usually accompanied by signs of parkinsonism. The sudden onset of symptoms over hours to a few weeks, often associated with physical or emotional stress, suggests a trigger initiating a nervous system insult resulting in permanent neurologic disability. We report the finding of six missense mutations in the gene for the Na+/K+-ATPase α3 subunit (ATP1A3) in seven unrelated families with RDP. Functional studies and structural analysis of the protein suggest that these mutations impair enzyme activity or stability. This finding implicates the Na+/K+ pump, a crucial protein responsible for the electrochemical gradient across the cell membrane, in dystonia and parkinsonism.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.
Annals of Neurology, 2002
Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SG... more Myoclonus-dystonia is a movement disorder associated with mutations in the ε-sarcoglycan gene (SGCE) in most families and in the DRD2 and DYT1 genes in two single families. In both of the latter families, we also found a mutation of SGCE. The molecular mechanisms through which the detected mutations may contribute to myoclonus-dystonia remain to be determined.