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931.
Ji Ae Lee Ha Yong Song Sung Mi Ju Su Jin Lee Hyung-Joo Kwon Won Sik Eum Sang Ho Jang Soo Young Choi Jinseu Park 《Experimental & molecular medicine》2009,41(9):629-637
Inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) have been known to be involved in various pathophysiological processes such as inflammation. This study was performed to determine the regulatory function of superoxide dismutase (SOD) on the LPS-induced expression of iNOS, and COX-2 in RAW 264.7 cells. When a cell-permeable SOD, Tat-SOD, was added to the culture medium of RAW 264.7 cells, it rapidly entered the cells in a dose-dependent manner. Treatment of RAW 264.7 cells with Tat-SOD led to decrease in LPS-induced ROS generation. Pretreatment with Tat-SOD significantly inhibited LPS-induced expression of iNOS and NO production but had no effect on the expression of COX-2 and PGE2 production in RAW 264.7 cells. Tat-SOD inhibited LPS-induced NF-κB DNA binding activity, IκBα degradation and activation of MAP kinases. These data suggest that SOD differentially regulate expression of iNOS and COX-2 in LPS-stimulated RAW 264.7 cells. 相似文献
932.
Ho Ki Shim Jeoung Yeon Kim Mi Jeong Kim Hee Sun Sim Dae Won Park Jang Wook Sohn Min Ja Kim 《Experimental & molecular medicine》2009,41(10):687-694
Legionella bacterium, an intracellular pathogen of mononuclear phagocytes, causes acute fatal pneumonia, especially in patients with impaired cellular immune responses. Until recently, however, the toll-like receptor (TLR) engagement of bacterial proteins derived from Legionella is uncertain. We previously showed that a 19-kDa highly conserved peptidoglycan-associated lipoprotein (PAL) of Legionella pneumophila induced the PAL-specific B cell and T cell responses in mice. In this study, we observed that the rPAL antigen of L. pneumophila, as an effector molecule, activated murine macrophages via TLR2 and produced proinflammatory cytokines such as IL-6 and TNF-α. In both BALB/c and TLR4-deficient C3H/HeJ mice, pretreatment of macrophages with anti-TLR2 mAb showed severely impaired cytokine production in response to the rPAL. In addition, in vitro the rPAL treatment increased the cell surface expression of CD40, CD80, CD86 and MHC I/II molecules. We further showed that the synthetic CpG-oligodeoxynucleotides (CpG ODN) coadministered with the rPAL enhanced IL-12 and IL-6 production and expression of CD40, CD80 and MHC II compared to the rPAL treatment alone. In conclusions, these results indicate that Legionella PAL might activate macrophages via a TLR2-dependent mechanism which thus induce cytokine production and expression of costimulatory and MHC molecules. 相似文献
933.
S.A. Saleem B.C. Jamalaiah J. Suresh Kumar A. Mohan Babu L. Rama Moorthy M. Jayasimhadri Kiwan Jang Ho Sueb Lee Soung Soo Yi Jung Hyun Jeong 《Solid State Sciences》2009,11(12):2093-2098
Nd3+ doped H3BO3–PbO–TeO2–RF (R = Li, Na and K) glasses were prepared through melt quenching technique. Optical absorption and near infrared (NIR) fluorescence spectra were recorded at room temperature. The spectral intensities were analyzed in terms of the Judd–Ofelt (J–O) parameters (Ωλ = 2, 4, 6). The covalency effect of Nd–O bond on the J–O parameters was estimated from the relative absorbance ratio (R) between 4I9/2 → 4F7/2 and 4I9/2 → 4S3/2 transitions. The effect of Nd–O covalency on the Ω4 and Ω6 intensity parameters as well as on the spontaneous emission probabilities (AR) was discussed. Lomheim and Shazer hybrid method was applied to determine the fluorescence branching ratios (βR) of each emission transition from the 4F3/2 metastable level to its lower lying levels. The evaluated total radiative transition probabilities (AT), stimulated emission cross-sections (σe) and gain bandwidth parameters (σe × ΔλP) were compared with the earlier reports. 相似文献
934.
An important problem in the theory of compressible gas flows is to understand the singular behavior of vacuum states. The main difficulty lies in the fact that the system becomes degenerate at the vacuum boundary, where the characteristic speeds u ± c coincide and have unbounded spatial derivative since c behaves like x1/2 close to the boundary. In this paper, we overcome this difficulty by presenting a new formulation and new energy spaces. We establish the local‐in‐time well‐posedness of one‐dimensional compressible Euler equations for isentropic flows with the physical vacuum singularity in some spaces adapted to the singularity. © 2009 Wiley Periodicals, Inc. 相似文献
935.
Synthesis of porous and nonporous ZnO nanobelt, multipod, and hierarchical nanostructure from Zn-HDS
Zn based hydroxide double salts (Zn-HDS) with an interlayer spacing of 20 Å was produced by dissolving dumbbell-like ZnO crystal. The resulting Zn-HDS with a ribbon-like shape has a suitable morphology to explore the remarkably mild procedure for synthesis of ZnO nanobelts. We found that the intercalated water molecules into the Zn-HDS could play a key role in the ZnO nanobelts porosity. The nonporous ZnO nanobelts were successfully synthesized from the Zn-HDS by soft-solution process at 95 °C through mild dehydration agent as Na2CO3. As-synthesized ZnO nanobelts were grown along not only the [0 1 −1 0], but also the [2 −1 −1 0]. On the other hand, the porous ZnO nanobelts were obtained from the Zn-HDS by calcinations at 200 and 400 °C. In addition, flower-like ZnO multipod and hierarchical nanostructures were produced from the Zn-HDS by using of strong dehydration agent (NaOH) through hydrothermal reaction at 150 and 230 °C. 相似文献
936.
Fe3O4 superparamagnetic nanoparticles with various functionalities were synthesized using a chemical co-precipitation method and used to demonstrate their analytical applications for protein separation of protein and metal ion extraction. The chemically inert silica layer coated with tetraethoxysilane (TEOS) protected the Fe3O4 core from a chemical attack and allowed the nanoparticles to be well dispersed in an aqueous solution. Particularly, the beads were resistant to an acidic solution with a pH ≥ 3. The amino (− NH2) groups were covalently bonded to the silica coated Fe3O4, and then the carboxyl (− COOH) groups were functionalized to the nanoparticle surface through the reaction of − NH2 and glutaric anhydride. The synthesized magnetic nanoparticles (MNP) were characterized using FT-IR, FE-TEM, XRD, and SQUID. The presence of functional groups on the nano beads was confirmed using molecular fluorescence spectrometry. For the presence of the amino (− NH2) groups, FITC was tagged and monitored using an excitation laser with a wavelength of 473 nm and a fluorescence emission of 518 nm. Biotin was immobilized on the MNP and the fluorescent of FITC tagged on avidin was monitored to identify the carboxyl (− COOH) group.The proteins of Cytochrome C (12,000 Da), Rnase B (15,000 Da), and Myoglobin (17,000 Da) were separated using the MNP functionalized with the carboxyl (− COOH) group and identified using MALDI-TOF-MS. Amino benzyl EDTA (ethylenediaminetetraacetic acid) was immobilized on the MNP for metal–EDTA complexation to use the synthesized magnetic particles to extract metal ions for environmental and clinical application. Cu, Cd, Co, and Pb ions were extracted from ∼ 10 ng/mL solutions in the batch-type procedure and the extraction efficiency was > 90% at a pH of 4. 相似文献
937.
Jhon YH Shim JG Kim JH Lee JH Jang KR Kim J 《The journal of physical chemistry. A》2010,114(49):12907-12913
Both nucleophilicities and accessibilities of three alkanolamines [monoethanolamine (MEA), (2-(methylamino)ethanol (MAE), and 2-amino-2-methyl-1-propanol (AMP)] were calculated to predict their reactivities with CO(2). After DFT geometry-optimization calculations, the global, group, and atomic nucleophilicities of each amine were obtained using MP2 quantum mechanical calculations. Only global nucleophilicity matched an experimental pK(a) order (MAE > AMP > MEA). However, it failed to predict the slow rate of the sterically hindered AMP and the order of rate constants, MAE > MEA > AMP. The accessibilities of amines to CO(2) have been calculated by MD simulations by monitoring collisions at the reaction centers: N atoms in amines and C in CO(2). The accessibility results indicate that global nucleophilicity needs quantitative correction for steric effects to predict better reactivities of amines with CO(2). 相似文献
938.
Hyeseon Cha Hyeon Joo Jeong Seung Pil Jang Joo Yeon Kim Dong Kwon Yang Jae Gyun Oh Woo Jin Park 《Experimental & molecular medicine》2010,42(1):61-68
Parathyroid hormone (PTH) treatment was previously shown to improve cardiac function after myocardial infarction by enhancing neovascularization and cell survival. In this study, pressure overload-induced left ventricular hypertrophy (LVH) was induced in mice by transverse aortic banding (TAB) for 2 weeks. We subsequently evaluated the effects of a 2-week treatment with PTH or saline on compensated LVH. After another 4 weeks, the hearts of the mice were analyzed by echocardiography, histology, and molecular biology. Echocardiography showed that hearts of the PTH-treated mice have more severe failing phenotypes than the saline-treated mice following TAB with a greater reduction in fractional shortening and left ventricular posterior wall thickness and with a greater increase in left ventricular internal dimension. Increases in the heart weight to body weight ratio and lung weight to body weight ratio following TAB were significantly exacerbated in PTH-treated mice compared to saline-treated mice. Molecular markers for heart failure, fibrosis, and angiogenesis were also altered in accordance with more severe heart failure in the PTH-treated mice compared to the saline-treated mice following TAB. In addition, the PTH-treated hearts were manifested with increased fibrosis accompanied by an enhanced SMAD2 phosphorylation. These data suggest that the PTH treatment may accelerate the process of decompensation of LV, leading to heart failure. 相似文献
939.
A new approach to preventing electrochemical carbon corrosion in the cathode of polymer electrolyte membrane fuel cells (PEMFCs) was developed. The addition of 2 wt % IrO(2) (0.016 mg cm(-2)) to the catalyst layer of the cathode was demonstrated to reduce the electrochemical corrosion of carbon by 76% at 1.6 V(NHE) and 70 °C compared with a commercial Pt/C catalyst of the same Pt loading of 0.4 mg cm(-2) and under the same test conditions. The IrO(2) was shown to behave as a catalyst for water electrolysis, thereby removing water from the catalyst layer, which promoted electrochemical carbon corrosion. 相似文献
940.
Dong Chun Kim Jeong Ah Kim Byung Sun Min Tae‐Su Jang MinKyun Na Seung Ho Lee 《Helvetica chimica acta》2010,93(4):692-697
Two new guaiane sesquiterpenoids, 11‐(acetyloxy)‐1,8‐dihydroxyguai‐4‐en‐3‐one ( 5 ) and (1α,6β)‐1,6‐dihydroxytorilin ( 6 ), were isolated from the fruits of Torilis japonica (Umbelliferae), along with four known sesquiterpenes, torilin ( 1 ), torilolone ( 2 ), (1β)‐1‐hydroxytorilin ( 3 ), and (1α)‐1‐hydroxytorilin ( 4 ). During the phytochemical investigation, daucosterol, friedelin, and epifriedelanol were also isolated from the plant for the first time. The structures of the new sesquiterpenoids 5 and 6 were determined by comprehensive analyses of MS and NMR spectroscopic data. These isolates were evaluated against human breast cancer cells (MCF‐7) and Lewis lung carcinoma (LLC) cells. Compounds 1, 3 , and 4 exhibited cytotoxic activity against the LLC cells with IC50 values of 31.3, 32.5, and 34.0 μg/ml, respectively. However, no significant cytotoxicity was found against the MCF‐7 cells for any of the compounds tested. 相似文献