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Find video protocols related to scientific articles indexed in Pubmed.
C-Type Lectin-like Receptor LOX-1 Promotes Dendritic Cell-Mediated Class-Switched B Cell Responses.
Immunity
PUBLISHED: 08-13-2014
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Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a pattern-recognition receptor for a variety of endogenous and exogenous ligands. However, LOX-1 function in the host immune response is not fully understood. Here, we report that LOX-1 expressed on dendritic cells (DCs) and B cells promotes humoral responses. On B cells LOX-1 signaling upregulated CCR7, promoting cellular migration toward lymphoid tissues. LOX-1 signaling on DCs licensed the cells to promote B cell differentiation into class-switched plasmablasts and led to downregulation of chemokine receptor CXCR5 and upregulation of chemokine receptor CCR10 on plasmablasts, enabling their exit from germinal centers and migration toward local mucosa and skin. Finally, we found that targeting influenza hemagglutinin 1 (HA1) subunit to LOX-1 elicited HA1-specific protective antibody responses in rhesus macaques. Thus, LOX-1 expressed on B cells and DC cells has complementary functions to promote humoral immune responses.
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Synthesis of wurtzite-zincblende Cu2ZnSnS4 and Cu2ZnSnSe4 nanocrystals: insight into the structural selection of quaternary and ternary compounds influenced by binary nuclei.
Nanoscale
PUBLISHED: 02-28-2014
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Nearly monodispersed wurtzite-dominant Cu2ZnSnS4 and zincblende-dominant Cu2ZnSnSe4 nanocrystals were successfully synthesized by mixing metal salts with heated thiourea or selenourea in oleylamine. A perspective of the structural relationship between quaternary and ternary semiconductors was investigated through the application of different anion sources to prepare Cu2SnS3 and Cu2SnSe3 nanocrystals. Investigations on copper-based binary compounds found that CuSe (or CuS) and Cu2Se (or Cu1.96S, Cu9S5) nuclei were primarily responsible for the formation of zincblende or wurtzite structures, respectively. Further management over these binary intermediates corresponded to slight structural transformations of the quaternary nanocrystals which could be observed not only in XRD patterns, but from optical and electrical properties as well. According to these results, Cu2ZnGeS4 nanocrystals with wurtzite-dominant structures were first reported using SC(NH2)2, which also verified that the binary semiconductors are the determinative factors.
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Cofilin Phosphorylation Decreased by Serum-free Starvation with Low Glucose in the L6 Myoblasts.
J Phys Ther Sci
PUBLISHED: 02-18-2014
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[Purpose] Many studies have been using cell culture models of muscle cells with exogenous cytokines or glucocorticoids to mimic atrophy in in vivo and in vitro tests. However, the changes in the phosphorylation of atrophy-related cofilin are still poorly understood in starved skeletal muscle cells. In this study, we first examined whether or not phosphorylation of cofilin is altered in L6 myoblasts after 3, 6, 12, 24, 48, and 72 hours of serum-free starvation with low glucose. [Methods] We used Western blotting to exam protein expression and phosphorylation in atrophied L6 myoblasts. [Results] L6 cell sizes and numbers were diminished as a result of serum-free starvation in a time-dependent manner. Serum-free starvation for 3, 6, 12, 24, 48, and 72 hours significantly decreased the phosphorylation of cofilin, respectively. [Conclusion] These results suggest that starvation-induced atrophy may be in part related to changes in the phosphorylation of cofilin in L6 myoblasts.
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Effect of applied voltage on the structural properties of SnO2 nanostuctures grown on indium-tin-oxide coated glass substrates.
J Nanosci Nanotechnol
PUBLISHED: 11-20-2013
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SnO2 nanostuctures were formed on indium-tin-oxide (ITO)-coated glass substrates by using an electrochemical deposition (ECD) method. X-ray photoelectron spectroscopy (XPS) spectra showed the existence of elemental Sn and O in the samples, indicative of the formation of SnO2 materials. An XPS spectrum showing the O 1s peak at a binding energy of 531.5 eV indicated that the oxygen atoms were bonded to the SnO2. Field-emission scanning electron microscopy (FE-SEM) images showed that the samples formed by using the ECD method had SnO2 nanostructures with a size between 280 and 350 nm. FE-SEM images showed that the size of the SnO2 nanostructures formed at 65 degrees C for 30 min increased with decreasing applied voltage. X-ray diffraction (XRD) patterns showed that the SnO2 nanostrucures had tetragonal structures with cell parameters of a = 4.738 A and c = 3.187 A. XRD results showed that the peak intensity of the (110) plane increased with decreasing applied voltage, indicative of a preferencial orientation of the (110) plane.
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Effect of a blocking layer on the decrease in the leakage current in organic bistable devices.
J Nanosci Nanotechnol
PUBLISHED: 11-12-2013
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The electrical bistabilities and the memory stabilities of organic bistable devices (OBDs) based on multi-core-shell CdSe/CdS/ZnS nanoparticles embedded in a polystyrene (PS) layer fabricated by using a spin-coating method were investigated. The current density-voltage (J-V) curves for the Al/multi-core-shell CdSe/CdS/ZnS nanoparticles embedded in PS layer/WO3/indium-tin-oxide (ITO) devices showed current bistability with a maximum ON/OFF ratio of 1 x 10(3), which was much larger than that of a device without a WO3 layer. The leakage current of the OBDs was decreased by insertion of the WO3 layer between the PS layer containing nanoparticles and the ITO electrode, resulting in a decrease in the current deviation between the experimental and the simulated currents in the low-voltage region. The effects of the WO3 blocking layer on the electrical characteristics of the OBDs were investigated, and the carrier transport mechanisms for the OBDs were described on the basis of the J-V experimental data and theoretical results.
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Degradation mechanisms of the program characteristics of 10 nm NAND flash memories due to cell-to-cell interference.
J Nanosci Nanotechnol
PUBLISHED: 11-12-2013
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The device characteristics of NAND flash memories with gate sizes from 14 to 32 nm were investigated by using a full three-dimensional technology computer-aided design simulator. Simulation results showed that the threshold voltage and the depletion regions of the floating gate (FG) of the 10-nm NAND flash memories increased with decreasing cell size. The electrical potential of the inter-poly-dielectric (IPD) surface and the tunneling layer surface decreased with increasing depletion region of the FG. The program characteristics of the 10-nm NAND flash memories decreased with decreasing electric potential on the IPD surface and the tunneling oxide surface. The electric field between the floating gate of the target cell and that of the neighboring cell increased with decreasing gate size due to a decrease in the distance between the two neighboring cells. The degradation mechanisms for the program characteristics of 10-nm NAND flash memories were clarified by changing the threshold voltage and the voltage shift.
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Strong quantum confinement effects in kesterite Cu2ZnSnS4 nanospheres for organic optoelectronic cells.
Nanoscale
PUBLISHED: 10-17-2013
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X-ray photoelectron spectra, X-ray diffraction patterns, scanning electron microscopy images, and high-resolution transmission electron microscopy images showed that the as-prepared samples were Cu2ZnSnS4 (CZTS) nanospheres with a kesterite phase. Ultraviolet-visible absorption spectra for the CZTS nanospheres with an average crystallite size of 3.26 nm showed that the absorption edge corresponding to the energy gap shifted to the higher energy side due to the quantum confinement within the CZTS nanoparticles. Current-density measurements showed that the power conversion efficiency (0.952%) of the organic photovoltaic cells with CZTS nanospheres was much higher than that (0.120%) of the cells without CZTS nanospheres.
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IRAK-M mediates Toll-like receptor/IL-1R-induced NF?B activation and cytokine production.
EMBO J.
PUBLISHED: 02-01-2013
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Toll-like receptors transduce their signals through the adaptor molecule MyD88 and members of the IL-1R-associated kinase family (IRAK-1, 2, M and 4). IRAK-1 and IRAK-2, known to form Myddosomes with MyD88-IRAK-4, mediate TLR7-induced TAK1-dependent NF?B activation. IRAK-M was previously known to function as a negative regulator that prevents the dissociation of IRAKs from MyD88, thereby inhibiting downstream signalling. However, we now found that IRAK-M was also able to interact with MyD88-IRAK-4 to form IRAK-M Myddosome to mediate TLR7-induced MEKK3-dependent second wave NF?B activation, which is uncoupled from post-transcriptional regulation. As a result, the IRAK-M-dependent pathway only induced expression of genes that are not regulated at the post-transcriptional levels (including inhibitory molecules SOCS1, SHIP1, A20 and I?B?), exerting an overall inhibitory effect on inflammatory response. On the other hand, through interaction with IRAK-2, IRAK-M inhibited TLR7-mediated production of cytokines and chemokines at translational levels. Taken together, IRAK-M mediates TLR7-induced MEKK3-dependent second wave NF?B activation to produce inhibitory molecules as a negative feedback for the pathway, while exerting inhibitory effect on translational control of cytokines and chemokines.
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Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon memory device with different tunneling oxide thicknesses.
J Nanosci Nanotechnol
PUBLISHED: 11-30-2011
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Nanoscale two-bit/cell NAND-type silicon-oxide-nitride-oxide-silicon (SONOS) flash memory devices with different tunneling oxide thicknesses were designed to reduce the short channel effect and the coupling interference. The process step and the electrical characteristics of the proposed SONOS memory devices were simulated by using SUPREM-4 and MEDICI, respectively. The short channel effect in the nanoscale two-bit/cell SONOS devices was decreased than that of the conventional devices due to a larger effective channel length. The drain current at the on-state of the proposed NAND SONOS memory devices decreased than that of the conventional NAND SONOS devices due to the high channel resistivity. The I on/I off ratio of the proposed NAND SONOS memory devices was larger than that of the conventional memory devices due to the dramatic decrease in the subthreshold current of the proposed devices. The electrical characteristics of the NAND SONOS memory devices with different tunneling oxide thicknesses were better than those of the conventional NAND SONOS devices.
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Electrical characteristics of nanoscale NAND silicon-oxide-nitride-oxide-silicon flash memory devices fabricated on SOI substrates.
J Nanosci Nanotechnol
PUBLISHED: 11-23-2011
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NAND silicon-oxide-nitride-oxide-silicon (SONOS) flash memory devices with double gates fabricated on silicon-on-insulator (SOI) substrates were proposed. The current-voltage characteristics related to the programming operation of the designed nanoscale NAND SONOS flash memory devices on a SOI substrate and on the conventional bulk-Si substrate were simulated and compared in order to investigate device characteristics of the scaled-down memory devices. The simulation results showed that the short channel effect and the subthreshod leakage current for the memory device with a large spacer length were lower than that of the memory device with a small spacer length due to increase of the effective channel length. The device performance of the memory device utilizing the SOI substrate exhibited a smaller subthreshold swing and a larger drain current level in comparison with those on the bulk-Si substrate. These improved electrical characteristices for the SOI devices could be explained by comparing the electric field distribution in a channel region for both devices.
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Charge trapping and luminance mechanisms of organic light-emitting devices with a 5,6,11,12-tetraphenylnaphthacene emission layer.
J Nanosci Nanotechnol
PUBLISHED: 11-23-2011
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The electrical and the optical properties of the organic light-emitting devices fabricated utilizing a 5,6,11,12-tetraphenylnaphthacene (rubrene) emission layer (EML) were investigated to clarify their charge trapping and luminance mechanisms. The increase in the thickness of the rubrene EML extended the width of the recombination zone, resulting in the enhancement of the efficiency and in the variation of the shoulder peak intensity of the electroluminescence spectra. The charge trapping and luminance mechanisms were affected by the total thickness of the rubrene layer, regardless of the existence of the barrier layers. The charge trapping and luminance mechanisms are described on the basis of the experimental results.
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Carrier dynamics and activation energy of CdxZn(1-x)Te/ZnTe quantum dots on GaAs and Si substrates.
J Nanosci Nanotechnol
PUBLISHED: 11-23-2011
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We have investigated the carrier dynamics and activation energy of CdxZn(1-x)Te/ZnTe quantum dots (QDs) on GaAs and Si substrates. The carrier dynamics of QDs on GaAs and Si substrates is studied using time-resolved photoluminescence (PL) measurements, revealing shorter exciton lifetimes of QDs on Si substrate. In particular, the activation energy of electrons confined in QDs on the GaAs substrate, as obtained from temperature-dependent PL spectra, is higher than that of electrons confined in QDs on the Si substrate. Both results confirm that defects and dislocations in QDs on the Si substrate provide nonradiative channels.
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Transforming growth factor-beta-activated kinase 1 regulates natural killer cell-mediated cytotoxicity and cytokine production.
J. Biol. Chem.
PUBLISHED: 07-19-2011
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Carma1, a caspase recruitment domain-containing membrane-associated guanylate kinase, initiates a unique signaling cascade via Bcl10 and Malt1 in NK cells. Carma1 deficiency results in reduced phosphorylation of JNK1/2 and activation of NF-?B that lead to impaired NK cell-mediated cytotoxicity and cytokine production. However, the precise identities of the downstream signaling molecules that link Carma1 to these effector functions were not defined. Here we show that transforming growth factor-? (TGF-?)-activated kinase 1 (TAK1) is abundantly present in NK cells, and activation via NKG2D results in its phosphorylation. Lack of Carma1 considerably reduced TAK1 phosphorylation, demonstrating the dependence of TAK1 on Carma1 in NKG2D-mediated NK cell activations. Pharmacological inhibitor to TAK1 significantly reduced NK-mediated cytotoxicity and its potential to generate IFN-?, GM-CSF, MIP-1?, MIP-1?, and RANTES. Conditional in vivo knockdown of TAK1 in NK cells from Mx1Cre(+)TAK1(fx/fx) mice resulted in impaired NKG2D-mediated cytotoxicity and cytokine/chemokine production. Inhibition or conditional knockdown of TAK1 severely impaired the NKG2D-mediated phosphorylation of ERK1/2 and JNK1/2 and activation of NF-?B and AP1. Our results show that TAK1 links Carma1 to NK cell-mediated effector functions.
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Polymer-ultrathin graphite sheet-polymer composite structured flexible nonvolatile bistable organic memory devices.
Nanotechnology
PUBLISHED: 06-20-2011
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We present data, which were obtained before bending and after bending, for the electrical bistabilities, memory stabilities, and memory mechanisms of three-layer structured flexible bistable organic memory (BOM) devices, which were fabricated utilizing the ultrathin graphite sheets (UGS) sandwiched between insulating poly(methylmethacrylate) (PMMA) polymer layers. The UGS were formed by transferring UGS (about 30 layers) and using a simple spin-coating technique. Transmission electron microscopy (TEM) measurements were performed to investigate the microstructural properties of the PMMA/UGS/PMMA films. Current-voltage (I-V) measurements were carried out to investigate the electrical properties of the BOM devices containing the UGS embedded in the PMMA polymer. Current-time (I-t) and current-cycle measurements under flat and bent conditions were performed to investigate the memory stabilities of the BOM devices. The memory characteristics of the BOM maintained similar device efficiencies after bending and were stable during repeated bendings of the BOM devices. The mechanisms for these characteristics of the fabricated BOM are described on the basis of the I-V results.
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White organic light-emitting devices utilizing a mixed color-conversion phosphor layer consisting of CaAl12O19:Mn and Zn2SiO4:Mn.
J Nanosci Nanotechnol
PUBLISHED: 04-02-2011
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White organic light-emitting devices (WOLEDs) were fabricated utilizing a mixed color-conversion layer consisting of CaAl12O19:Mn and Zn2SiO4:Mn phosphors. The ratio between the CaAl12O19:Mn and the Zn2SiO4:Mn phosphor determined the rate of the red and the green lights. The color rendering index was improved by using a mixed color-conversion phosphor layer.
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Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon devices with a separated double-gate saddle-type structure.
J Nanosci Nanotechnol
PUBLISHED: 04-02-2011
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Nanoscale two-bit/cell NAND silicon-oxide-nitride-oxide-silicon flash memory devices based on a separated double-gate (SDG) saddle structure with a recess channel region had two different doping regions in silicon-fin channel to operate two-bit per cell. A simulation results showed that the short channel effect, the cross-talk problem between cells, and the increase in threshold voltage distribution were minimized, resulting in the enhancement of the scaling-down characteristics and the program/erase speed.
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Memory effects of nonvolatile memory devices with a floating gate fabricated utilizing Ag nanoparticles embedded into a polymethylmethacrylate layer.
J Nanosci Nanotechnol
PUBLISHED: 03-31-2011
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Nonvolatile memory devices based on a polymethylmethacrylate (PMMA) layer containing Ag nanoparticles were formed by using a spin coating method. High-resolution transmission electron microscopy images showed that Ag nanoparticles were randomly distributed in the PMMA layer. Capacitance-voltage (C-V) curves for the Al/Ag nanoparticles embedded in a PMMA layer/p-Si(100) device at 300 K showed a hysteresis with a large flat-band voltage shift, indicative of the Ag nanoparticles acting as the charge storage in the memory device. The magnitude of the flat-band voltage shift for the memory devices increased with increasing Ag nanoparticle concentration. The operating mechanisms for the writing and the erasing processes for the Al/Ag nanoparticles embedded in a PMMA layer/p-Si(100) device are described on the basis of the C-V results and electronic structures.
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Charging and discharging mechanisms of organic bistable devices based on ZnO nanoparticles capped with a poly N-vinylcarbazole polymer.
J Nanosci Nanotechnol
PUBLISHED: 03-31-2011
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Scanning electron microscopy and energy-dispersive spectrometer images of hybrid nanocomposites of ZnO nanoparticles capped with a poly N-vinylcarbazole (PVK) that was fabricated using the spin-coating technique showed that the ZnO nanoparticles were capped with a PVK polymer layer. The measurement of the current-voltage (I-V) of the Al/ZnO nanoparticles capped with a PVK layer/indium-tin-oxide/glass devices at 300 K showed electrical bistability and negative differential resistance, which indicate the nonvolatile nature of the memory effect of the electron captured in the ZnO nanoparticles. The charging and discharging mechanisms of the organic bistable devices that were fabricated using hybrid nanocomposites of ZnO nanoparticles capped with a PVK layer are described based on the I-V results.
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Therapeutic effects of fermented red ginseng in allergic rhinitis: a randomized, double-blind, placebo-controlled study.
Allergy Asthma Immunol Res
PUBLISHED: 02-14-2011
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Allergic rhinitis is clinically defined as a disorder of the nose induced by IgE mediated inflammation after allergen exposure of the nasal mucosa. Many reports have stated that Panax ginseng and fermented red ginseng have anti-inflammatory effects, especially against Th2-type inflammation. This study was conducted to evaluate the therapeutic effects of fermented red ginseng in allergic rhinitis.
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The kinase activity of interleukin-1 receptor-associated kinase 2 is essential for lipopolysaccharide-mediated cytokine and chemokine mRNA stability and translation.
J. Interferon Cytokine Res.
PUBLISHED: 02-03-2011
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Interleukin-1 receptor-associated kinase 2 (IRAK2) has been shown to be essential for lipopolysaccharide (LPS)-mediated posttranscriptional control of cytokine and chemokine production. In this study, we investigated the role of IRAK2 kinase activity in LPS-mediated posttranscriptional control by reconstituting IRAK2-deficient macrophages with either wild-type or kinase-inactive IRAK2. Compared with wild-type IRAK2 (IRAK2-WT) macrophages, kinase-inactive IRAK2 (IRAK2-KD) macrophages show reduced cytokine and chemokine mRNA stability and translation in response to LPS. Further, LPS-treated IRAK2-KD macrophages also show reduced activation of MKK3/6, MNK1, and eIF4E and attenuated toll-like receptor 4-induced tristetraprolin modification and stabilization. Taken together, these results suggest that the kinase activity of IRAK2 is required for the optimal activation of mitogen-activated protein kinase signaling, which regulates cytokine and chemokine production at posttranscriptional levels.
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The critical role of IL-1 receptor-associated kinase 4-mediated NF-?B activation in modified low-density lipoprotein-induced inflammatory gene expression and atherosclerosis.
J. Immunol.
PUBLISHED: 01-28-2011
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Exciting discoveries related to IL-1R/TLR signaling in the development of atherosclerosis plaque have triggered intense interest in the molecular mechanisms by which innate immune signaling modulates the onset and development of atherosclerosis. Previous studies have clearly shown the definitive role of proinflammatory cytokine IL-1 in the development of atherosclerosis. Recent studies have provided direct evidence supporting a link between innate immunity and atherogenesis. Although it is still controversial about whether infectious pathogens contribute to cardiovascular diseases, direct genetic evidence indicates the importance of IL-1R/TLR signaling in atherogenesis. In this study, we examined the role of IL-1R-associated kinase 4 (IRAK4) kinase activity in modified low-density lipoprotein (LDL)-mediated signaling using bone marrow-derived macrophage as well as an in vivo model of atherosclerosis. First, we found that the IRAK4 kinase activity was required for modified LDL-induced NF-?B activation and expression of a subset of proinflammatory genes but not for the activation of MAPKs in bone marrow-derived macrophage. IRAK4 kinase-inactive knockin (IRAK4KI) mice were bred onto ApoE(-/-) mice to generate IRAK4KI/ApoE(-/-) mice. Importantly, the aortic sinus lesion formation was impaired in IRAK4KI/ApoE(-/-) mice compared with that in ApoE(-/-) mice. Furthermore, proinflammatory cytokine production was reduced in the aortic sinus region of IRAK4KI/ApoE(-/-) mice compared with that in ApoE(-/-) mice. Taken together, our results indicate that the IRAK4 kinase plays an important role in modified LDL-mediated signaling and the development of atherosclerosis, suggesting that pharmacological inhibition of IRAK4 kinase activity might be a feasible approach in the development of antiatherosclerosis drugs.
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The dual functions of IL-1 receptor-associated kinase 2 in TLR9-mediated IFN and proinflammatory cytokine production.
J. Immunol.
PUBLISHED: 01-26-2011
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Bone marrow-derived plasmacytoid dendritic cells (pDCs) from IL-1R-associated kinase (IRAK)2-deficient mice produced more IFNs than did wild-type pDCs upon stimulation with the TLR9 ligand CpG. Furthermore, in CpG-stimulated IRAK2-deficient pDCs there was increased nuclear translocation of IFN regulatory factor 7, the key transcription factor for IFN gene transcription in these cells. In IRAK2-deficient macrophages, enhanced NF-?B activation and increased expression of CpG-induced genes were detected within 2 h after treatment. However, at later times, NF-?B activation was decreased and, in contrast to the results with IFN, there was less secretion of other proinflammatory cytokines (such as TNF-?) and chemokines in CpG-stimulated IRAK2-deficient pDCs and macrophages. Therefore, although IRAK2 is a negative regulator of TLR9-mediated IFN production through its modulation of the transcriptional activity of IFN regulatory factor 7, it is also a positive regulator of TLR9-mediated proinflammatory cytokine and chemokine production at some level subsequent to transcription.
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Electrical bistabilities and memory mechanisms of organic bistable devices fabricated utilizing SnO2 nanoparticles embedded in a poly(methyl methacrylate) layer.
J Nanosci Nanotechnol
PUBLISHED: 12-09-2010
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Organic bistable devices fabircated utilizing SnO2 nanoparticles embedded in a poly(methyl methacrylate) (PMMA) polymer layer were formed by using a spin coating method. Transmission electon microscopy images and photoluminescence spectra showed that synethized SnO2 nanoparticles were randomly distributed in the dibutyl ehter solution. Current-voltage (I-V) measurements on the Al/SnO2 nanoparticles embedded in PMMA layer/ITO devices at 300 K showed current bistability due to the existence of SnO2 nanoparticles. Current-time (I-t) results showed the memory retention characteristic of the device. Carrier transport mechanisms of the device are described on the basis of the I-V experimental results and electronic structures.
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Operating mechanisms of organic bistable devices containing ZnO nanoparticles embedded in a poly-4-vinyl-phenol layer.
J Nanosci Nanotechnol
PUBLISHED: 12-07-2010
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Scanning electron microscopy images showed that self-assembled ZnO nanoparticles were created inside a poly-4-vinyl-phenol (PVP) layer. Current-voltage (I-V) measurements on the Al/ZnO nanoparticles embedded in a PVP layer/indium tin oxide (ITO)/glass device fabricated by using a simple spin coating method at 300 K showed an electrical hysteresis behavior, indicative of an essential feature for a bistable device. The data fitting results of the I-V curves showed that the carrier transport mechanisms at low and high voltages were attributed to the space charge limited current and the Fowler-Nordheim tunneling processes, respectively. Possible operating mechanisms for the memory effects in the Al/ZnO nanoparticles embedded in a PVP layer/ITO devices are described on the basis of the I-V results.
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Charge storage variations of organic memory devices fabricated by using C60 molecules embedded in an insulating polymer layer with Au and Al electrodes.
J Nanosci Nanotechnol
PUBLISHED: 12-07-2010
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Organic memory devices based on a hybrid poly(4-vinyl phenol) (PVP) layer containing Buckminster-fullerene (C60) were formed by using a spin coating method. Capacitance-voltage measurements on Al/C60 embedded in PVP layer/p-Si (100) devices at 300 K showed a hysteresis with a large flatband voltage shift due to the existence of C60 molecules, indicative of the charge storage in the C60 molecules. The magnitude of the flat-band voltage shift for the memory devices with a hybrid active layer consisting of PVP and C60 was significantly affected by the type of electrode. The endurance time of the organic memory device fabricated utilizing C60 nanoparticles embedded in the PVP layer at 300 K was approximately 10 years, indicative of excellent memory endurance ability.
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Carrier transport mechanisms of the writing and the erasing processes for Al/ZnO nanoparticles embedded in a polymethyl methacrylate layer/C60/p-Si diodes.
J Nanosci Nanotechnol
PUBLISHED: 12-07-2010
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Transmission electron microscopy images showed that ZnO nanoparticles were randomly distributed inside the polymethyl methacrylate (PMMA) layer. Capacitance-voltage (C-V) measurements on the Al/ZnO nanoparticles embedded in a PMMA layer/C60/p-Si diode at 300 K showed a clockwise hysteresis with a flatband voltage shift due to existence of the ZnO nanoparticles and a C60 buffer layer. The insertion of the C60 layer enlarged the memory window of the device containing the ZnO nanoparticle, as estimated by the flatband voltage shift in the C-V hysteresis. Capacitance-time measurements showed that the devices exhibited excellent memory retention ability at ambient conditions. Operating mechanisms of the charge injection, capture, and emission in the active layer and the charging and the discharging processes in the devices are described on the basis of the C-V results.
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Flexible organic bistable devices based on graphene embedded in an insulating poly(methyl methacrylate) polymer layer.
Nano Lett.
PUBLISHED: 05-28-2010
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The electrical properties of flexible nonvolatile organic bistable devices (OBDs) fabricated with graphene sandwiched between two insulating poly(methyl methacrylate) (PMMA) polymer layers were investigated. Current-voltage (I-V) measurements on the Al/PMMA/graphene/PMMA/indium-tin-oxide/poly(ethylene terephthalate) devices at 300 K showed a current bistability due to the existence of the graphene, indicative of charge storage in the graphene. The maximum ON/OFF ratio of the current bistability for the fabricated OBDs was as large as 1 x 10(7), and the endurance number of ON/OFF switchings was 1.5 x 10(5) cycles, and an ON/OFF ratio of 4.4 x 10(6) was maintained for retention times larger than 1 x 10(5) s. No interference effect was observed for the scaled-down OBDs containing a graphene layer. The memory characteristics of the OBDs maintained similar device efficiencies after bending and were stable during repetitive bendings of the OBDs. The mechanisms for these characteristics of the fabricated OBDs are described on the basis of the I-V results.
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Direct fabrication of zero- and one-dimensional metal nanocrystals by thermally assisted electromigration.
ACS Nano
PUBLISHED: 05-15-2010
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Zero- and one-dimensional metal nanocrystals were successfully fabricated with accurate control in size, shape, and position on semiconductor surfaces by using a novel in situ fabrication method of the nanocrystal with a biasing tungsten tip in transmission electron microscopy. The dominant mechanism of nanocrystal formation was identified mainly as local Joule heating-assisted electromigration through the direct observation of formation and growth processes of the nanocrystal. This method was applied to extracting metal atoms with an exceedingly faster growth rate ( approximately 10(5) atoms/s) from a metal-oxide thin film to form a metal nanocrystal with any desired size and position. By real-time observation of the microstructure and concurrent electrical measurements, it was found that the nanostructure formation can be completely controlled into various shapes such as zero-dimensional nanodots and one-dimensional nanowires/nanorods.
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Luminance efficiency enhancement in green organic light-emitting devices fabricated utilizing a cesium fluoride/fullerene heterostructure electron injection layer.
J Nanosci Nanotechnol
PUBLISHED: 04-03-2010
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Enhancement mechanisms of the luminance efficiency in green organic light-emitting devices (OLEDs) fabricated utilizing a cesium fluoride (CsF)/fullerene (C60) heterostructure acting as an electron injection layer (EIL) were investigated. The luminance efficiencies as functions of the current density showed that the luminance efficiency in the green OLEDs fabricated utilizing a CsF/C60 heterostructure acting as an EIL was higher than that in the green OLEDs fabricated utilizing a CsF, a Liq, or a C60 single EIL. The interfacial dipole existing at the CsF layer decreased the electron injection barrier, and the stability of the OLEDs with a CsF EIL was enhanced due to the lower diffusion rate of Cs atoms in comparison with Li atoms. The enhancement of the luminance efficiency of the OLEDs with a heterostructure EIL was attributed to the increase in the electron injection. These results can help improve understanding of the enhancement mechanisms of the luminance efficiency in green OLEDs utilizing a CsF/C60 heterostructure acting as an EIL.
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Luminance mechanisms in green organic light-emitting devices fabricated utilizing tris(8-hydroxyquinoline)aluminum/4,7-diphenyl-1, 10-phenanthroline multiple heterostructures acting as an electron transport layer.
J Nanosci Nanotechnol
PUBLISHED: 04-03-2010
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The electrical and the optical properties in green organic light-emitting devices (OLEDs) fabricated utilizing tris(8-hydroxyquinoline)aluminum (Alq3)/4,7-diphenyl-1,10-phenanthroline (BPhen) multiple heterostructures acting as an electron transport layer (ETL) were investigated. The operating voltage of the OLEDs with a multiple heterostructure ETL increased with increasing the number of the Alq3/BPhen heterostructures because more electrons were accumulated at the Alq3/BPhen heterointerfaces. The number of the leakage holes existing in the multiple heterostructure ETL of the OLEDs at a low voltage range slightly increased due to an increase of the internal electric field generated from the accumulated electrons at the Alq3/BPhen heterointerface. The luminance efficiency of the OLEDs with a multiple heterostructure ETL at a high voltage range became stabilized because the increase of the number of the heterointerface decreased the quantity of electrons accumulated at each heterointerface.
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Dependences of the electrical properties on the diameter and the doping concentration of the Si nanowire field effect transistors with a Schottky metal-semiconductor contact.
J Nanosci Nanotechnol
PUBLISHED: 04-03-2010
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A compact model of the current-voltage (I-V) characteristics for the Si nanowire field effect transistor (FET) taking into account dependence of the analytical electrical properties on the diameter and the concentration of the Si nanowire of the FETs with a Schottky metal-semiconductor contact has been proposed. I-V characteristics of the nanowire FETs were analytically calculated by using a quantum drift-diffusion current transport model taking into account an equivalent circuit together with the quantum effect of the Si nanowires and a Schottky model at Schottky barriers. The material parameters dependent on different diameters and concentrations of the Si nanowire were numerically estimated from the physical properties of the Si nanowire. The threshold voltage, the mobility, and the doping density of the Si nanowire and the Schottky barrier height at a metal-Si nanowire heterointerface in the nanowire FET were estimated by using the theoretical model.
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Enhancement of the memory effects for nonvolatile memory devices fabricated utilizing ZnO nanoparticles embedded in a Si3N4 layer.
J Nanosci Nanotechnol
PUBLISHED: 04-03-2010
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ZnO nanoparticles embedded in a Si3N4 layer by using spin-coating and thermal treatment were fabricated to investigate the feasible applications in charge trapping regions of the metal/oxide/nitride/oxide/p-Si memory devices. The magnitude of the flatband voltage shift of the capacitance-voltage (C-V) curve for the Al/SiO2/ZnO nanoparticles embedded in Si3N4 layer/SiO2/p-Si memory device was larger than that of Al/ZnO nanoparticles embedded in SiO2 layer/p-Si and Al/SiO2/Si3N4/SiO2/p-Si devices. The increase in the flatband voltage shift of the C-V curve for the Al/SiO2/ZnO nanoparticles embedded in Si3N4 layer/SiO2/p-Si memory device in comparison with other devices was attributed to the existence of the ZnO nanoparticles or the interface trap states between the ZnO nanoparticles and the Si3N4 layer resulting from existence of ZnO nanoparticles embedded in the Si3N4 layer.
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A case of recurrent toxocariasis presenting with urticaria.
Allergy Asthma Immunol Res
PUBLISHED: 03-22-2010
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Human toxocariasis is the most prevalent helminthiasis in Korea and other industrialized countries. The clinical features of toxocariasis are diverse, according to the involved organ. Typically, Toxocara spp. infection is easily treated with 400 mg albendazole twice a day for 5 days. However, we experienced a case of recurrent toxocariasis that was refractory to this standard therapy and presented with urticaria, an uncommon symptom in toxocariasis. A 35-year-old male visited our emergency room because of abdominal pain. He had recently consumed raw cow liver (3 weeks prior to presentation). Laboratory analyses revealed eosinophilia (1,612 cells/µL) and increased total IgE (3,060 IU/mL). Chest X-ray showed multiple lung nodules in both lungs, and computed tomography revealed multiple ground-glass opacities in both lungs and multiple tiny liver abscesses. Liver biopsy revealed an eosinophilic abscess. Enzyme-linked immunosorbent assay findings for Toxocara antigens were positive (optical density, 2.140), leading to a diagnosis of toxocariasis. We initiated a 5-day treatment with albendazole and prednisolone; however, 6 days after completing the treatment, the patient again experienced urticaria and severe itching that could not be controlled by antihistamines or hydrocortisone cream. A second bout of eosinophilia suggested recurring toxocariasis, for which we prescribed a second round of albendazole. Despite an initial improvement in his symptoms, the patient returned after 6 weeks complaining of abdominal pain for 6 hours, which was reminiscent of his first attack; he also exhibited eosinophilia. Accordingly, albendazole was administered once more for an additional 3 weeks, and his symptoms resolved.
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The receptor SIGIRR suppresses Th17 cell proliferation via inhibition of the interleukin-1 receptor pathway and mTOR kinase activation.
Immunity
PUBLISHED: 01-07-2010
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Interleukin-1 (IL-1)-mediated signaling in T cells is essential for T helper 17 (Th17) cell differentiation. We showed here that SIGIRR, a negative regulator of IL-1 receptor and Toll-like receptor signaling, was induced during Th17 cell lineage commitment and governed Th17 cell differentiation and expansion through its inhibitory effects on IL-1 signaling. The absence of SIGIRR in T cells resulted in increased Th17 cell polarization in vivo upon myelin oligodendrocyte glycoprotein (MOG(35-55)) peptide immunization. Recombinant IL-1 promoted a marked increase in the proliferation of SIGIRR-deficient T cells under an in vitro Th17 cell-polarization condition. Importantly, we detected increased IL-1-induced phosphorylation of JNK and mTOR kinase in SIGIRR-deficient Th17 cells compared to wild-type Th17 cells. IL-1-induced proliferation was abolished in mTOR-deficient Th17 cells, indicating the essential role of mTOR activation. Our results demonstrate an important mechanism by which SIGIRR controls Th17 cell expansion and effector function through the IL-1-induced mTOR signaling pathway.
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White light-emitting diodes fabricated utilizing hybrid polymer-colloidal ZnO quantum dots.
Nanotechnology
PUBLISHED: 08-18-2009
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White light-emitting diodes (WLEDs) with a hybrid poly N-vinylcarbazole (PVK) and poly(methyl methacrylate) (PMMA) polymer and ZnO quantum dots (QDs) were fabricated by a spin-coating technique. Transmission electron microscopy images showed that the ZnO QDs were predominantly distributed at the circumference of the surface of the PVK polymer. Electroluminescence spectra for hybrid polymer-QD WLEDs showed a broad peak around 600 nm. The Commission Internationale de IEclairage chromaticity coordinates of the WLEDs fabricated utilizing hybrid polymer-QD WLEDs at 10 V were (0.39, 0.41), indicative of a white emission. The luminescence mechanisms of the WLEDs are described.
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Electrical bistabilities and memory stabilities of nonvolatile bistable devices fabricated utilizing C(60) molecules embedded in a polymethyl methacrylate layer.
Nanotechnology
PUBLISHED: 08-04-2009
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Current-voltage (I-V) measurements on Al/fullerene (C(60)) molecules embedded in polymethyl methacrylate/Al devices at 300 K showed a current bistability due to the existence of the C(60) molecules. The on/off ratio of the current bistability for the memory devices was as large as 10(3). The retention time of the devices was above 2.5 x 10(4) s at room temperature, and cycling endurance tests on these devices indicated that the ON and OFF currents showed no degradation until 50,000 cycles. Carrier transport mechanisms for the nonvolatile bistable devices are described on the basis of the I-V experimental and fitting results.
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Electroluminescence of a single active layer polymer-nanocrystal hybrid light-emitting diode with inversion symmetry.
Nanotechnology
PUBLISHED: 06-16-2009
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A hybrid polymer-nanocrystal (NC) light-emitting diode (LED) device with a single active layer structure is simply fabricated by a spin coating. From a high-resolution transmission electron microscopy (HRTEM) study, each PVK polymer particle is observed to be capped with TPBi molecules and CdSe/ZnS NCs are mainly distributed along the circumference of PVK and TPBi surfaces, resulting in a core-shell polymer-NC hybrid of [CdSe/ZnS]/TPBi/[CdSe/ZnS]/PVK. An Al/[CdSe/ZnS]/TPBi/[CdSe/ZnS]/PVK/indium-tin oxide(ITO)/glass LED shows electroluminescence (EL) centered at around 585 nm at the forward bias of +10 V, which clearly reveals that CdSe/ZnS NCs existing at the interface between PVK and TPBi act as recombination centers for excitons. In particular, EL can be observed at both forward bias and reverse bias, and this means that this device with an isotropic distribution of NCs has an inversion symmetry.
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Carrier transport in flexible organic bistable devices of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) polymer layer.
Nanotechnology
PUBLISHED: 04-20-2009
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The bistable effects of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) (PMMA) polymer single layer by using flexible polyethylene terephthalate (PET) substrates were investigated. Transmission electron microscopy (TEM) images revealed that ZnO nanoparticles were formed inside the PMMA polymer layer. Current-voltage (I-V) measurement on the Al/ZnO nanoparticles embedded in an insulating PMMA polymer layer/ITO/PET structures at 300 K showed a nonvolatile electrical bistability behavior with a flat-band voltage shift due to the existence of the ZnO nanoparticles, indicative of trapping, storing, and emission of charges in the electronic states of the ZnO nanoparticles. The carrier transport mechanism of the bistable behavior for the fabricated organic bistable device (OBD) structures is described on the basis of the I-V results by analyzing the effect of space charge.
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Electrical bistabilities and operating mechanisms of memory devices fabricated utilizing ZnO quantum dot-multi-walled carbon nanotube nanocomposites.
Nanotechnology
PUBLISHED: 04-14-2009
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Transmission electron microscopy images showed that the ZnO quantum dots (QDs) were conjugated with multi-walled carbon nanotubes (MWCNTs). Bistable memories utilizing an ensemble of the ZnO QD-MWCNT heterostructures were developed and the storage capability of the devices was significantly enhanced due to the conjugation of the ZnO QDs and the MWCNTs. Operating mechanisms of memory devices fabricated utilizing the ZnO QD-MWCNT heterostructures are described on the basis of the current-voltage results. The memory devices exhibited excellent environmental stability at ambient conditions.
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Wavelength tunable triggered single-photon source from a single CdTe quantum dot on silicon substrate.
Nano Lett.
PUBLISHED: 03-31-2009
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Triggered single-photon emission from a single CdTe quantum dot (QD) grown on Si(001) substrate is demonstrated for the first time. The emission wavelength of QDs can be tuned in a wide spectral range (more than 8 meV) using a focused laser beam. A nearly perfect single-photon emission from the exciton lines is preserved even after energy tuning. The lifetime is also measured before and after laser processing, and no appreciable change is observed.
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Flexible photovoltaic cells fabricated utilizing ZnO quantum dot/carbon nanotube heterojunctions.
Nanotechnology
PUBLISHED: 03-24-2009
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In situ growth of ZnO quantum dots (QDs) on the surface of multi-walled carbon nanotubes (MWCNTs) was presented, and their application in photovoltaic cells by using flexible polyethylene terephthalate substrates was demonstrated. High-resolution transmission electron microscopy images revealed the conjugation of ZnO QDs with MWCNTs. Photoluminescence spectra indicated that the charge transfer efficiency at ZnO QD-MWCNT heterojunctions was above 90%, as confirmed by time-resolved photoluminescence measurements. Current-voltage measurements on the flexible devices fabricated utilizing ZnO QD-MWCNT heterojunctions showed the robust nature of the ZnO QD-MWCNT-based photovoltaic cells and their potential applications as the power source for flexible hand-held consumer electronics.
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Interleukin-1 receptor-associated kinase 2 is critical for lipopolysaccharide-mediated post-transcriptional control.
J. Biol. Chem.
PUBLISHED: 02-18-2009
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IRAK2, a member of the interleukin-1 receptor-associated kinase (IRAK) family, has been implicated in Toll-like receptor (TLR)-mediated signaling. We generated IRAK2-deficient mice to examine its function in detail. These mice are resistant to lipopolysaccharide-induced septic shock, because of impaired TLR4-mediated induction of pro-inflammatory cytokines and chemokines. Although IRAK2 deficiency did not affect TLR4-mediated NFkappaB activation, a reduction of lipopolysaccharide (LPS)-mediated mRNA stabilization contributed to the reduced cytokine and chemokine production observed in bone marrow-derived macrophages from IRAK2-deficient mice. Furthermore, the ratios of LPS-induced cytokine and chemokine mRNAs in translation-active (polysomal) versus translation-inactive (free ribosomes) pools were reduced in IRAK2-deficient macrophages compared with wild type macrophages. Importantly, LPS-induced phosphorylation of MKK3/6, MNK1, and eIF4E was significantly reduced in IRAK2-deficient macrophages compared with wild type macrophages. Moreover, LPS stimulation induced an interaction of IRAK2 with TRAF6, MKK3/6, and MK2, implicating a critical role for mitogen-activated protein kinase signaling in LPS-induced IRAK2-mediated post-transcriptional control. These results reveal that IRAK2 is required for LPS-mediated post-transcriptional control of cytokine and chemokine expression, which plays an essential role in TLR4-induced septic shock.
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Carrier transport mechanisms of bistable memory devices fabricated utilizing core-shell CdSe/ZnSe quantum-dot/multi-walled carbon nanotube hybrid nanocomposites.
Nanotechnology
PUBLISHED: 02-02-2009
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Transmission electron microscopy images showed that conjugation between single core-shell CdSe/ZnSe quantum dots (QDs) and oxidized multi-walled carbon nanotubes (MWCNTs) was achieved through the complexation reaction. Current-voltage (I-V) measurements on Al/CdSe:MWCNT conjugated nanocomposite/indium-tin-oxide devices at 300 K showed that the on/off ratio of the current bistability was as large as about 10(4), which was significantly increased due to an enhancement of the carrier transfer efficiency between the CdSe/ZnSe QDs and the MWCNTs. Carrier transport mechanisms of the bistable memory devices fabricated utilizing CdSe/ZnSe QD/MWCNT hybrid nanocomposite are described on the basis of the I-V results.
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The creation of sub-10 nm In(PO3)3 nanocrystals in an insulating matrix, and underlying formation mechanisms.
Nanotechnology
PUBLISHED: 01-12-2009
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Sub-10 nm In(PO(3))(3) nanocrystals (NCs) were created in an insulating matrix by rapid thermal annealing to form nanocomposite structures. On annealing at a temperature of 400 degrees C, P(2)O(5) NCs were formed by substituting P for Zn atoms in ZnO films via the kickout diffusion mechanism based on the fixed oxygen sublattice. On annealing at a higher temperature of 600 degrees C, however, In(PO(3))(3) NCs were nucleated by diffusion of In atoms from the substrate into the sites of P(2)O(5) NCs that coalesced by moving atoms to neighboring grains in the strain relaxed region. The formation mechanisms of sub-10 nm In(PO(3))(3) NCs in an insulating matrix due to rapid thermal annealing are described on the basis of the experimental results.
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Flexible white organic light-emitting devices with a porous red polymer layer and a blue small molecular layer utilizing a phase separation of blended polymer.
J Nanosci Nanotechnol
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Flexible white organic light-emitting devices (WOLEDs) with an emitting layer consisting of a porous red poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH-PPV) polymer layer and a blue 4,4-bis(2,2-diphenylvinyl)-1,1-biphenyl (DPVBi) small molecular layer were fabricated on polyethylene terephthalate substrates. The current density of the flexible WOLEDs fabricated with a blend layer formed with a higher spincoating speed was significantly higher than that of a device fabricated with a lower spincoating speed, due to the higher pore density. The ratio between the red and the blue color peak intensities of the electroluminescence spectra for the flexible WOLEDs with a porous red MEH-PPV polymer layer and a blue DPVBi small molecular layer was controlled by the spincoating speed of the blend layer.
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Pellino 2 is critical for Toll-like receptor/interleukin-1 receptor (TLR/IL-1R)-mediated post-transcriptional control.
J. Biol. Chem.
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Interleukin 1 receptor-associated kinase 1(IRAK1), a key molecule in TLR/IL-1R-mediated signaling, is phosphorylated, ubiquitinated, and degraded upon ligand stimulation. We and others have recently identified Pellino proteins as novel RING E3 ubiquitin ligases involved in IRAK1 polyubiquitination and degradation. However, it remains unclear how each Pellino member distinctly regulates TLR/IL-1R signaling by modulating IRAK1 ubiquitination. In this study we examined the role of Pellino 2 in IL-1- and LPS-mediated signaling and gene expression by knocking down Pellino 2 in human 293-IL-1R cells and primary bone marrow macrophages. Pellino 2 (but not Pellino 1) knockdown abolished IL-1- and LPS-induced Lys-63-linked IRAK1 ubiquitination with reduced Lys-48-linked IRAK1 ubiquitination. Furthermore, Pellino 2 is required for TAK1-dependent NF?B activation. However, because of the retained TAK1-independent NF?B activation, the levels of IL-1- and LPS-induced NF?B activation were not substantially affected in Pellino 2 knockdown 293-IL-1R cells and primary macrophages, respectively. On the other hand, Pellino 2 knockdown reduced the IL-1- and LPS-induced inflammatory gene expression at late time points, which was accompanied by increased decay rates of the mRNAs of the inflammatory genes. Importantly, IL-1- and LPS-mediated JNK and ERK activation were substantially attenuated in Pellino 2 knock-down cells, implicating MAPK activation in TLR/IL-1R-induced mRNA stabilization. Taken together, this study demonstrated that Pellino 2 plays a critical role for TLR/IL-1R-mediated post-transcriptional control.
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Carrier transport mechanisms of phosphorescent organic light-emitting devices fabricated utilizing a N,N-dicarbazolyl-3,5-benzene: 1,3,5-tri(phenyl-2-benzimidazole)-benzene mixed host emitting layer.
J Nanosci Nanotechnol
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The electrical and the optical properties of phosphorescent organic light-emitting devices (PHOLEDs) fabricated utilizing a mixed host emitting layer (EML) consisting of N,N-dicarbazolyl-3,5-benzene (mCP) and 1,3,5-tri(phenyl-2-benzimidazole)-benzene (TPBi) were investigated to clarify the carrier transport mechanisms of PHOLEDs. While the operating voltage of the PHOLEDs with a mixed host EML significantly decreased due to the insertion of TPBi with a high electron mobility, the quantum efficiency of the PHOLEDs decreased due to the hindrance of the exciton energy transfer by TPBi molecules. The electroluminescence spectra for the PHOLEDs with an tris(2-phenylpyridine)iridium-doped mixed host EML showed that the TPBi molecules in the mixed host EML increased the electron injection into the mixed host EML, resulting in a decrease of the shift length of the recombination zone in comparison with a single host EML.
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Significant enhancement of the power conversion efficiency for organic photovoltaic cells due to a P3HT pillar layer containing ZnSe quantum dots.
Opt Express
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High-efficiency organic photovoltaic (OPV) cells utilizing a poly(3-hexylthiophene) (P3HT) pillar layer containing ZnSe quantum dots (QDs) were fabricated by using a mixed solution method. Scanning electron microscopy and high-resolution transmission electron microscopy images showed that the ZnSe QDs were dispersed in the P3HT layer. The power conversion efficiency of the OPV cells with a P3HT pillar layer containing ZnSe QDs was as much as 100% higher than that of the OPV cells with a planar layer due to an enhancement of the photon-harvesting ability of the congregated P3HT particles containing ZnSe QDs and to an increase of the interfacial region for efficient charge transport.
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Phospholipid scramblase 1 regulates Toll-like receptor 9-mediated type I interferon production in plasmacytoid dendritic cells.
Cell Res.
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Toll-like receptor 9 (TLR9) senses microbial DNA in the endosomes of plasmacytoid dendritic cells (pDCs) and triggers MyD88-dependent type I interferon (IFN) responses. To better understand TLR9 biology in pDCs, we established a yeast two-hybrid library for the identification of TLR9-interacting proteins. Here, we report that an IFN-inducible protein, phospholipid scramblase 1 (PLSCR1), interacts with TLR9 in pDCs. Knockdown of PLSCR1 expression by siRNA in human pDC cell line led to a 60-70% reduction of IFN-? responses following CpG-ODN (oligodeoxynucleotide) stimulation. Primary pDCs from PLSCR1-deficient mice produced lower amount of type 1 IFN than pDCs from the wild-type mice in response to CpG-ODN, herpes simplex virus and influenza A virus. Following CpG-A stimulation, there were much lower amounts of TLR9 in the early endosomes together with CpG-A in pDCs from PLSCR1-deficient mice. Our study demonstrates that PLSCR1 is a TLR9-interacting protein that plays an important role in pDCs type 1 IFN responses by regulating TLR9 trafficking to the endosomal compartment.
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Split-Second Nanostructure Control of a Polymer:Fullerene Photo-active Layer by using Intensely Pulsed White Light for Highly Efficient Production of Polymer Solar Cells.
ACS Appl Mater Interfaces
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Intense pulsed white light (IPWL) treatment was tested as an ultra-fast, large-area processable optical technique for the control of the nanostructure of a polymeric bulk-heterojunction photoactive layer in order to improve the efficiencies of polymer solar cells. Only two seconds of IPWL irradiation of a polymer:fullerene photoactive layer under ambient conditions was found to significantly enhance the power conversion efficiencies of the tested polymer solar cells to values approaching that of typical devices treated with thermal annealing. Consecutive white-light pulses from the xenon lamp induce the self-organization of the polymeric donor into an ordered structure and result in the optimized phase-segregation of the polymeric donor and the fullerene acceptor in the photoactive layer, which enhances the light absorption and hole mobility, and results in efficient photocurrent generation. The effects on device performance of varying the pulse conditions, including the pulse energy, pulse duration, and number of pulses, were systematically investigated. Finally, it was successfully demonstrated that the IPWL treatment produces flexible polymer solar cells. The proposed IPWL process is suitable for the efficient industrial roll-to-roll production of polymer solar cells.
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