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881.
Kim KO Park SY Han CW Chung HK Yoo DH Ryu DH Han JS 《Experimental & molecular medicine》2008,40(3):286-293
The purpose of this study was to identify the effect of sildenafil citrate on IL-1β-induced nitric oxide (NO) synthesis and iNOS expression in human synovial sarcoma SW982 cells. IL-1β stimulated the cells to generate NO in both dose- and time-dependent manners. The IL-1β-induced NO synthesis was inhibited by guanylate cyclase (GC) inhibitor, LY83583. When the cells were treated with 8-bromo-cGMP, a hydrolyzable analog of cGMP, NO synthesis was increased upto 5-fold without IL-1β treatment suggesting that cGMP is an essential component for increasing the NO synthesis. Synoviocytes and chondrocytes contain strong cGMP phosphodiesterase (PDE) activity, which has biochemical features of PDE5. When SW982 cells were pretreated with sildenafil citrate (Viagra), a PDE5 specific inhibitor, sildenafil citrate significantly inhibited IL-1β-induced NO synthesis and iNOS expressions. From this result, we noticed that PDE5 activity is required for IL-1β-induced NO synthesis and iNOS expressions in human synovial sarcoma cells, and sildenafil citrate may be able to suppress an inflammatory reaction of synovium through inhibition of NO synthesis and iNOS expression by cytokines. 相似文献
882.
Metal ion induced FRET OFF-ON in tren/dansyl-appended rhodamine 总被引:1,自引:0,他引:1
A series of new fluorescent probes bearing tren-spaced rhodamine B and dansyl groups have been synthesized. Compound 1 exhibits selective changes in the absorption and the emission spectra toward Cu2+ ion over miscellaneous metal cations. Among 1-3, 1 shows the best FRET efficiency through dansyl emission to rhodamine absorption for the Cu2+ ion. 相似文献
883.
Dr. Juliana S. A. Carneiro Dr. Giada Innocenti Hyun June Moon Yoseph Guta Laura Proaño Prof. Dr. Carsten Sievers Dr. Miles A. Sakwa-Novak Dr. Eric W. Ping Prof. Dr. Christopher W. Jones 《Angewandte Chemie (International ed. in English)》2023,62(24):e202302887
Direct air capture (DAC) processes for extraction of CO2 from ambient air are unique among chemical processes in that they operate outdoors with minimal feed pretreatments. Here, the impact of humidity on the oxidative degradation of a prototypical solid supported amine sorbent, poly(ethylenimine) (PEI) supported on Al2O3, is explored in detail. By combining CO2 adsorption measurements, oxidative degradation rates, elemental analyses, solid-state NMR and in situ IR spectroscopic analysis in conjunction with 18O labeling of water, a comprehensive picture of sorbent oxidation is achieved under accelerated conditions. We demonstrated that the presence of water vapor can play an important role in accelerating the degradation reactions. From the study we inferred the identity and kinetics of formation of the major oxidative products, and the role(s) of humidity. Our data are consistent with a radical mediated autooxidative degradation mechanism. 相似文献
884.
Antibody immobilization on a solid support is an essential process for the development of most immune-based assay systems. The choice of the immobilization method greatly affects antibody-antigen interactions on the assay surface. For the past several years, numerous strategies have been reported to control antibody immobilization, mainly by directing the orientation, stability, and density of bound antibodies on different assay platforms. Here we discuss recent developments in antibody immobilization methods with a particular focus on the strengths and limitations of reported approaches, and thereby provide a useful guideline for the selection of suitable antibody coupling procedures. 相似文献
885.
The signal amplification technique of peptide nucleic acid (PNA)-based electrochemical DNA sensor was developed in a label-free and one-step method utilizing enzymatic catalysis. Electrochemical detection of DNA hybridization on a PNA-modified electrode is based on the change of surface charge caused by the hybridization of negatively charged DNA molecules. The negatively charged mediator, ferrocenedicarboxylic acid, cannot diffuse to the DNA hybridized electrode surface due to the charge repulsion with the hybridized DNA molecule while it can easily approach the neutral PNA-modified electrode surface without the hybridization. By employing glucose oxidase catalysis on this PNA-based electrochemical system, the oxidized mediator could be immediately reduced leading to greatly increased electrochemical signals. Using the enzymatic strategy, we successfully demonstrated its clinical utility by detecting one of the mutation sequences of the breast cancer susceptibility gene BRCA1 at a sample concentration lower than 10(-9) M. Furthermore, a single base-mismatched sample could be also discriminated from a perfectly matched sample. 相似文献
886.
Sun Young Kim Yun Seon Yeon Seung Min Park Jeong Hyun Kim Jae Kyu Song 《Chemical physics letters》2008,462(1-3):100-103
Photoluminescence (PL) of zinc oxide (ZnO) nanorods with an average thickness of 5 nm and a length of 30 nm is blue-shifted compared to the bulk due to quantum confinement effects. The exciton states remain relatively stable at a high carrier density due to a smaller exciton size and an enhanced exciton binding energy in the quantum confined nanorods, whereas the electron-hole plasma states are formed in the bulk at the similar carrier density. A linear dependence of the PL intensity on the excitation intensity also corroborates the assumption that the stable exciton states are responsible for the undisturbed emission at a high carrier density. 相似文献
887.
Hak‐Ju Lee Seon‐Mi Seo Oh‐Kyu Lee Hyun‐Jin Jo Ha‐Young Kang Don‐Ha Choi Ki‐Hyon Paik Merajuddin Khan 《Helvetica chimica acta》2008,91(12):2361-2366
The Et2O‐soluble fraction from the bark of Magnolia kobus led to the isolation of two new lignans, (+)‐(7α,7′α,8α,8′α)‐3′,4,4′,5,5′‐pentamethoxy‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 1 ) and (+)‐(7α,7′α,8α,8′α)‐4,5‐dimethoxy‐3′,4′‐(methylenedioxy)‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 2 ), along with five known lignans 3 – 7 . Their structures were established on the basis of various spectroscopic analyses including 1D‐ (1H, 13C, and DEPT) and 2D‐NMR (COSY, NOESY, HMQC, and HMBC) and by comparison of their spectral data with those of related compounds. 相似文献
888.
The reaction of (COD)PdCl 2 (COD = 1,5-cyclooctadiene) with bis(3-pyridyl)methylphenylsilane (L) in acetone affords single crystals consisting of cyclodimers, [PdCl 2(L)] 2, whereas the reaction in a mixture of dichloromethane and ethanol yields amorphous spheres consisting of cyclotrimers, [PdCl 2(L)] 3. The interconversion and morphology control between the crystals and the microspheres can be explained by the difference in flexibility between the cyclodimer and cyclotrimer. 相似文献
889.
Indium was substituted at gallium site in chalcopyrite AgGaS(2) structure by using a simple solid solution method. The spectroscopic analysis using extended x-ray absorption fine structure and x-ray photoelectron spectroscopy confirmed the indium substitution in AgGaS(2) lattice. The band gap energy of AgGa(1-x)In(x)S(2) (x=0-1) estimated from the onset of absorption edge was found to be reduced from 2.67 eV (x=0) to 1.9 eV (x=1) by indium substitution. The theoretical and experimental studies showed that the indium s orbitals in AgGa(1-x)In(x)S(2) tailored the band gap energy, thereby modified the photocatalytic activity of the AgGa(1-x)In(x)S(2). 相似文献
890.
Heung‐Seop Yim Mi‐Ra Kim Gi‐Hyeon Sung Hyun‐A Chung Jin‐Kook Lee Sang‐Gyeong Lee Yong‐Jin Yoon 《Journal of heterocyclic chemistry》2008,45(1):215-220