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ABSTRACT: Cross-dehydrogenative coupling of various terminal alkynes and monohydrosilanes efficiently proceeded in the presence of gold supported on OMS-2 (Au/OMS-2) using O2 as a terminal oxidant, affording the corresponding alkynylsilanes in moderate to high yields. The observed catalysis was truly heterogeneous, and the catalyst could be reused at least ten times without a significant loss of its high catalytic performance.
Angewandte Chemie International Edition 04/2013; · 13.45 Impact Factor
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ABSTRACT: Cardiac sympathetic hyperinnervation after myocardial infarction (MI) is associated with a high incidence of lethal arrhythmia. However, the mechanisms of nerve sprouting induced by MI are unclear. In this study, we showed a nuclear factor-κB (NF-κB) signaling pathway involved in cardiac sympathetic hyperinnervation after MI in rabbit hearts. An MI model was induced by ligation of the coronary artery in rabbits, which were then euthanized after 7 days. Rabbits with MI showed sympathetic hyperinnervation, as revealed by immunohistochemical analysis of the density of nerve fibers positive for growth-associated protein 43 (GAP43) and tyrosine hydroxylase (TH). Using western blot and real-time RT-PCR techniques, we found that MI was associated with activation of NF-κB signaling and consequent upregulation of nerve growth factor. Intravenous administration with the NF-κB inhibitor pyrrolidine dithiocarbamate (100mg/kg/day) inhibited NF-κB activation and ameliorated sympathetic hyperinnervation after MI. These results suggest that cardiac nerve sprouting after MI is associated in part with NF-κB activation and may be one of the mechanisms responsible for sympathetic hyperinnervation induced by MI.
Neuroscience Letters 01/2013; · 2.11 Impact Factor
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ABSTRACT: In the presence of amorphous MnO(2), various methylarenes (even with two or more methyl groups) could be selectively converted into the corresponding primary monoamides in moderate to high yields. The observed catalysis was truly heterogeneous, and the retrieved amorphous MnO(2) catalyst could be reused without an appreciable loss of its catalytic performance.
Angewandte Chemie International Edition 06/2012; 51(29):7250-3. · 13.45 Impact Factor
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ABSTRACT: Gold nanoparticles loaded onto Keggin-type insoluble polyoxometalates (Cs(x)H(3-x)PW(12)O(40)) showed superior catalytic performances for the direct conversion of cellobiose into gluconic acid in water in the presence of O(2). The selectivity of Au/Cs(x)H(3-x)PW(12)O(40) for gluconic acid was significantly higher than those of Au catalysts loaded onto typical metal oxides (e.g., SiO(2), Al(2)O(3), and TiO(2)), carbon nanotubes, and zeolites (H-ZSM-5 and HY). The acidity of polyoxometalates and the mean-size of the Au nanoparticles were the key factors in the catalytic conversion of cellobiose into gluconic acid. The stronger acidity of polyoxometalates not only favored the conversion of cellobiose but also resulted in higher selectivity of gluconic acid by facilitating desorption and inhibiting its further degradation. On the other hand, the smaller Au nanoparticles accelerated the oxidation of glucose (an intermediate) into gluconic acid, thereby leading to increases both in the conversion of cellobiose and in the selectivity of gluconic acid. The Au/Cs(x)H(3-x)PW(12)O(40) system also catalyzed the conversion of cellulose into gluconic acid with good efficiency, but it could not be used repeatedly owing to the leaching of a H(+)-rich hydrophilic moiety over long-term hydrothermal reactions. We have demonstrated that the combination of H(3)PW(12)O(40) and Au/Cs(3.0)PW(12)O(40) afforded excellent yields of gluconic acid (about 85%, 418 K, 11 h), and the deactivation of the recovered H(3)PW(12)O(40)-Au/Cs(3.0)PW(12)O(40) catalyst was not serious during repeated use.
Chemistry 03/2012; 18(10):2938-47. · 5.93 Impact Factor
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ABSTRACT: Propylene from methane: The transformation of methane to propylene has been realized in a two-step route via CH(3) Cl or CH(3) Br. CeO(2) serves as an efficient and stable catalyst for the oxidative chlorination and bromination of methane to CH(3) Cl and CH(3) Br. In the second step, a modified zeolite is highly a selective and stable catalyst for the conversion of CH(3) Cl or CH(3) Br into propylene.
Angewandte Chemie International Edition 03/2012; 51(10):2438-42. · 13.45 Impact Factor
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ABSTRACT: Because genes that are highly expressed in the cochlea after noise stress may have crucial regulatory roles in hearing, the identification of these genes may be useful for restoring normal auditory function. This study assessed altered gene expression at 1h following the cessation of noise exposure by using microarrays and real-time polymerase chain reaction (qPCR) in rats. In addition, the auditory threshold shifts and morphological changes of hair cells were observed. This study indicated that applied noise induced outer hair cell loss and a 40-50 dB hearing loss. Totally 239 altered genes were involved in the immune system process, response to stress, or response to stimulus. The expression of five up-regulated genes (Reg3b, Lcn2, Serpina3n, Nob1 and Hamp) was confirmed by qPCR. Future experiments will focus on several of these new candidate genes and may provide insight into the underlying auditory pathophysiology.
Gene 03/2012; 499(2):318-22. · 2.34 Impact Factor
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ABSTRACT: Corneal degenerations, occurring either spontaneously or as a complication to other diseases, cause vision problems by endangering corneal transparency. Our past cornea research projects involving mice revealed that some recruited mice presented corneal problems similar to human corneal degeneration. The present study examines the histology of diseased mice corneas, including ultrastructure. Genome-wide microarray and proteomic methods were utilized to screen for molecular changes in the diseased corneas. It was found that abnormalities affected mainly anterior layers of the corneas. The most often observed histological abnormalities included neoplasm or detachment of the epithelial layer, erosion or breakage of Bowman membranes, blood vessel formation, and bleeding in the stroma. Microarray assay showed that among the 46 up-regulated probes in diseased corneas, 13 were for lens crystallins. However, all corneal crystallins genes remained unchanged. αA-crystallin was among the proteins that showed the greatest increase in diseased corneas, as detected by gel electrophoresis. We propose that lens crystallins, rather than corneal crystallins, are involved in the pathological process of corneal degeneration. Further study along these lines would provide insight into the mechanism of corneal transparency.
Experimental Eye Research 03/2012; 96(1):55-64. · 3.26 Impact Factor
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ABSTRACT: Abnormal sympathetic innervation underlies both long-term hyperglycemia and myocardial infarction (MI). The incidence of ventricular arrhythmias (VAs) after MI is higher in diabetic than in nondiabetic patients. However, the exact mechanism remains unclear. In this study, we aimed to explore sympathetic neural remodeling after MI in diabetic rabbits and its relationship with VAs.
Rabbits were randomly assigned to 4 groups: control, diabetes mellitus (DM), MI and diabetic myocardial infarction (DI). After electrophysiological experiments in vivo, immunohistochemistry and real-time RT-PCR were used to measure sympathetic innervations. To test the function of sympathetic nerve fibers, norepinephrine levels were measured by high-performance liquid chromatography.
The corrected QT interval and QT dispersion were significantly more prolonged with DI than other conditions. The density of tyrosine hydroxylase-positive fibers and corresponding mRNA abundance was significantly higher with DI than with DM and under control conditions, but was lower than with the MI group. Moreover, the distribution and structure of regenerated nerve was heterogeneous in DI rabbits. Norepinephrine content was higher in the DI group, and accompanied by an increased quantity of tyrosine hydroxylase-positive fibers.
MI results in sympathetic neural remodeling in diabetic rabbits, which may be responsible in part for the increased occurrence of VAs.
Cardiology 02/2012; 121(1):1-9. · 1.71 Impact Factor
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ABSTRACT: Manganese oxide octahedral molecular sieves (OMS-2) could act as an efficient, reusable heterogeneous catalyst for transformation of various primary amines to the corresponding primary amides through the sequence of oxidative dehydrogenation and successive hydration.
Chemical Communications 02/2012; 48(20):2642-4. · 6.17 Impact Factor
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ABSTRACT: A new strain of influenza A (H1N1) virus is a major cause of morbidity and mortality around the world. The neuraminidase of the influenza virus has been the most potential target for the anti-influenza drugs such as oseltamivir and zanamivir. However, the emergence of drug-resistant variants of these drugs makes a pressing need for the development of new neuraminidase inhibitors for controlling illness and transmission. Here a 3D structure model of H1N1 avian influenza virus neuraminidase type 1 (N1) was constructed based on the structure of the template H5N1 avian influenza virus N1. Upon application of virtual screening technique for N1 inhibitors, two novel compounds (ZINC database ID: ZINC02128091, ZINC02098378) were found as the most favorable interaction energy with N1. Docking results showed that the compounds bound not only in the active pocket, but also in a new hydrophobic cave which contains Arg368, Trp399, Ile427, Pro431 and Lys432 of N1. Our result suggested that both of the screened compounds containing the hydrophobic group bring a strong conjugation effect with Arg293, Arg368 Lys432 of N1 by pi-pi interaction. However, the control inhibitors zanamivir and oseltamivir do not have this effect. The details of N1-compound binding structure obtained will be valuable for the development of a new anti-influenza virus agent.
Journal of Molecular Modeling 01/2012; 18(8):3445-53. · 1.80 Impact Factor
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ABSTRACT: We report here a method for measurement of thermoelectric power of quasi-one dimensional nano-materials with a simple platform, where individual nanomaterial is assembled with nano-probes in a scanning electron microscope. This approach allows repeated manipulation and thermoelectric measurement of the same loaded nanosample with adjustable number of individual nanotubes or nanowires. It also allows assembly of multiple samples on one measurement stage. For multi-walled carbon nanotube bundles, we have observed a weak trend that, when the number of individual tubes in a bundle varies from ten millions to around a hundred thousand, the thermoelectric power almost remains at around 10 microV/K. When the tube number in the bundle is further reduced, the up-limit of the thermoelectric power gradually increases to a value near 20 microV/K.
Journal of Nanoscience and Nanotechnology 08/2010; 10(8):4985-91. · 1.56 Impact Factor
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Chemistry Letters - CHEM LETT. 01/2006; 35(6):572-573.
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ABSTRACT: Mesoporous molecular sieves containing iron sites with different dispersions and environments were studied for the partial oxidation of methane and the epoxidation of propylene. The tetrahedral Fe(III) sites incorporated inside the framework of SBA-15 showed higher HCHO selectivity under a similar CH4 conversion than the oligomeric FeOx clusters located in the mesopores in the partial oxidation of CH4 by O2. HCHO selectivity of the FeOx clusters in SBA-15 could be improved by the modification with either an acidic group (e.g., phosphate) or an alkali metal ion, which increased the dispersion or changed the local coordination environment of iron species. The catalyst containing FePO4 clusters formed by the modification with phosphate exhibited the best catalytic performances for HCHO formation. This catalyst also showed uniquely high selectivities to HCHO and CH3OH as N2O was used as the oxidant for the partial oxidation of CH4. For the epoxidation of propylene to propylene oxide (PO), the modification of the FeOx/SBA-15 with an alkali metal salt typified by KCl was effective. Among many SBA-15-supported transition metal oxides modified by KCl, the KCl-FeOx/SBA-15 showed the best catalytic performances for the epoxidation of propylene by N2O. The comparative studies using N2O and O2 as the oxidant revealed that N2O was necessary for PO formation over the KCl-FeOx/SBA-15 catalyst.
Catalysis Today - CATAL TODAY. 01/2006; 117(1):156-162.
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Chemistry Letters - CHEM LETT. 01/2002;
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ABSTRACT: A series of CeO2–ZrO2 composite oxides (Ce1−xZrxO2) was characterized and tested for the gas-solid reaction with CH4 in the absence of gaseous oxidant. A solid solution with fluorite structure was formed for the samples with Zr content below 50% (x≤0.5). For Ce1−xZrxO2 both desorption of O2 and reduction by H2 took place at lower temperatures as compared with that for CeO2 alone. Like CeO2, the reaction of Ce1−xZrxO2 with CH4 selectively produced synthesis gas with a H2/CO ratio of 2, but the formation rates of H2 and CO were increased and the activation energy was remarkably decreased due to the incorporation of ZrO2 into CeO2. The reaction was further accelerated by the presence of Pt catalyst. The conversion of CH4 to H2 and CO could be achieved at a temperature as low as 500°C by using Ce0.8Zr0.2O2 in the presence of Pt. The reduced Ce0.8Zr0.2O2−y could be oxidized with H2O back to Ce0.8Zr0.2O2, producing pure H2 simultaneously.
Applied Catalysis A-general - APPL CATAL A-GEN. 01/1999; 183(2):317-324.
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ABSTRACT: In situ FTIR studies showed the generation of a peroxide species by the contact of a H2-O2 gas mixture or of N2O with Fe-Al-P-O catalysts at 573 K. This oxygen species oxidized methane into methanol at 473 K, through the formation of methoxide species on the catalysts.
Catalysis Letters 08/1995; 35(3):259-263. · 2.24 Impact Factor
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ABSTRACT: Four kinds of reconstituted tobacco sheets were heated in a thermogravimetric analyzer in different atmospheres at the heating rate of 5 °C/min. The curves of thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA) of the reconstituted tobacco sheets were measured and compared. The profiles of the evolving product CO2 were also recorded by the thermogravimetric analyzer coupled to a Fourier transform infrared (TG-FTIR) spectrometer. The results of thermal analysis and the profiles of CO2 showed that the existence of O2 could strongly affect the thermal decomposition of the reconstituted tobacco sheets.
Thermochimica Acta.
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ABSTRACT: Based on the coupled-mode theory, the power transfer among “- - -” arranged parallel single-mode optical fibers has been investigated. The analysis shows that the distances between each two of the N fibers centers have effects on the coupling coefficient and power transfer. The solution of the coupled equations for three parallel single-mode optical fibers is given, and is studied for different initial conditions comparatively. Numerical simulations show that power transfer will be periodical during coupling among parallel single-mode optical fibers. These results can be extended to multi-parallel single-mode optical fibers.
Optik - International Journal for Light and Electron Optics.
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ABSTRACT: Direct conversion of methane into useful chemicals remains as a big challenge in catalysis in the 21st century. A large number of studies have contributed to the direct conversion of methane in the past decade. Although there is still no direct process with commercial viability at this moment, many new methods and catalysts have been developed for the direct activation and conversion of methane. This review highlights the recent novel approaches to the partial oxidation of methane into useful oxygenates with an emphasis on the selective formation of methanol in the presence of H2.
Applied Catalysis A: General.
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ABSTRACT: We have demonstrated the crystalline ZnO–Al2O3 core–shell nanowire structure by atomic layer deposition (ALD) at a temperature 100 °C. The core–shell structure could have potential applications in the fabrication of ZnO field effect transistor. After dissolving the ZnO core, shape defined, rigid and robust crystalline Al2O3 shelled nanostructures have been fabricated. Nanowire ZnO nanostructures have been replicated by alumina shell. This is one of the most effective techniques for producing core–shell or shell/hollowed nanostructures of any desired objects. The Al2O3 shelled nanostructures could have potential applications as space confined nanoreactors, drug delivery, nanofluidic channels and optical transmitting.
Applied Surface Science.
