Model cobalt catalysts for CO 2 hydrogenation were prepared using colloidal chemistry. The turnover frequency at 6 bar and at 200−300°C increased with cobalt nanoparticle size from 3 to 10 nm. It was demonstrated that near monodisperse nanoparticles in the size range of 3−10 nm could be generated without using trioctylphosphine oxide, a capping ligand that we demonstrate results in phosphorus being present on the metal surface and poisoning catalyst activity in our application.KEYWORDS: Cobalt nanoparticles, CO 2 hydrogenation, heterogeneous catalysis, catalytic poisoning C obalt-catalyzed processes and specifically the conversion of synthesis gas to hydrocarbons using cobalt (Co), Fischer−Tropsch synthesis, although long established, 1 have recently become a topic of renewed interest. This results from increased demand and declining fossil fuel reserves making both gas-to-liquid and biomass-to-liquid attractive routes to transportation fuels. 2 Especially when derived from biomass, the synthesis gas typically contains a significant fraction of CO 2 , however studies on CO 2 hydrogenation and its catalytic mechanism on Co are much less well developed than the analogous reaction with CO. 3,4 Because of its environmental impact through the greenhouse effect, fixation of CO 2 by reaction (rather than simply capture and storage) also makes studying the possibility of Co-catalyzed CO 2 hydrogenation a topic of considerable interest. 4 Additionally, there is an important technical precedent in terms of producing desirable oxygenated products by incorporation of CO 2 in such reactions (important in producing synthetic fuels). In the case of classical Cu/ZnO catalyzed methanol production, Chinchen et al. demonstrated using isotopic labeling studies that it is CO 2 , rather than CO, that is incorporated in the methanol produced. 5 Few kinetic studies of the chemistry of Co-catalyzed CO 2 hydrogenation exist. In our laboratory the conversion of CO 2 to CH 4 was explored at atmospheric pressure in a batch reactor over high-purity Co foil, 6 subsequently Welder and co-workers also studied the hydrogenation of CO 2 over Co foils in a flow reactor. 7,8 Wetherbee and Bartholomew however have reported on the use of a Co/SiO 2 catalyst prepared by incipient wetness impregnation to obtain various kinetic parameters, 9 although this does not contain information at the atomic scale about the nature of the Co catalyst particles, and it is this problem that we now address.In our laboratory size-and morphology-controlled nanoparticles, which are synthesized using colloidal techniques, have allowed the production of model catalysts via deposition within mesoporous silica supports. This is important because selectivity in multipath reactions has been found to vary with catalyst particle size and shape. In combination with powerful characterization techniques that provide atomic-and molecularlevel information, these model nanoparticle catalysts have been employed in studying fundamental mechanistic questions in many key chemica...

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BackgroundEmerging evidences have verified that long non-coding RNAs (lncRNAs) play important regulatory roles in the pathogenesis and progression of cancers. lncRNAs metastasis associated lung adenocarcinoma transcript 1 (MALAT1) have been found to be up-regulated in some human cancers. The main objective of this study was to investigate the expression level and biological function of MALAT1 in gastric cancer (GC).MethodsQuantificational real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA levels of MALAT1 in 78 paired gastric carcinoma tissues and adjacent normal tissues, and the associations of MALAT1 expression with the clinicopathological features were analyzed, and the prognosis of gastric carcinoma patients was evaluated. The HMGB2 mRNA and protein expressions were detected by qRT-PCR and western-blot analysis. Luciferase reporter assay was used to determine miR-1297 was a target of MALAT1.ResultsIn this study, we demonstrated MALAT1 was up-regulation in GC tissues compared with adjacent normal tissues and higher MALAT1 expression was correlated with local invasion, lymph node metastasis and TNM stage. Patients with higher MALAT1 expression predicted a shorter survival and poor prognosis. Functionally, we revealed that MALAT1 promoted cells proliferation and invasion in GC. Mechanistically, our results demonstrated that MALAT1 was negatively correlation with miR-1297 and functioned as a molecular sponging miR-1297, antagonizing its ability to suppress HMGB2 expression.ConclusionsTaken together, these results demonstrated that MALAT1/miR-1297/HMGB2 axis acted as critical regulator pathway in GC tumorigenesis and progression, which provided a novel therapeutic target for gastric cancer.

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PEG-rhG-CSF is a more convenient and safe formulation and a more effective prophylactic measure in breast cancer patients receiving multiple cycles of chemotherapy.