The Effect of Iron Oxide Magnetic Nanoparticles on Smooth Muscle Cells

Recently, magnetic nanoparticles of iron oxide (Fe3O4, γ-Fe2O3) have shown an increasing number of applications in the field of biomedicine, but some questions have been raised about the potential impact of these nanoparticles on the environment and human health. In this work, the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) with the same crystal structure, magnetic properties, and size distribution was designed, prepared, and characterized by transmission electronic microscopy, powder X-ray diffraction, zeta potential analyzer, vibrating sample magnetometer, and Fourier transform Infrared spectroscopy. Then, we have investigated the effect of the three types of magnetic nanoparticles (DMSA-Fe2O3, APTS-Fe2O3, and GLU-Fe2O3) on smooth muscle cells (SMCs). Cellular uptake of nanoparticles by SMC displays the dose, the incubation time and surface property dependent patterns. Through the thin section TEM images, we observe that DMSA-Fe2O3is incorporated into the lysosome of SMCs. The magnetic nanoparticles have no inflammation impact, but decrease the viability of SMCs. The other questions about metabolism and other impacts will be the next subject of further studies

A Study of Methyl Formate Production from Carbon Dioxide Hydrogenation in Methanol over a Copper Zinc Oxide Catalyst

A preliminary study of the production of methyl formate (MF) from CO 2 hydrogenation in liquid methanol was carried out over a Cu/ZnO/Al2O3 based catalyst which was synthesized by a precipitation technique following a well established route. The effects of amine concentration, hydrogen pressure, temperature, CO and water addition on the activity and selectivity of MF were investigated. It is of interest to note that the addition of 1% trimethylamine can dramatically increase the initial turnover frequency with the MF being the major product. It is evident that the formation of CO2-amine adduct promotes the catalytic hydrogenation of CO2 on the surface of the catalyst. © 2010 Springer Science+Business Media, LLC

Comparative Study of Catalytic Hydrogenation of 9-Ethylcarbazole for Hydrogen Storage over Noble Metal Surfaces

The use of liquid organic hydrides (LOH) as a chemical hydrogen store to supply hydrogen gas for a polymer electrolyte membrane fuel cell (PEFC) is explored. In the present work, hydrogenation of 9-ethylcarbazole is particularly investigated in the liquid phase over different unsupported noble metal powders. The kinetics obtained from the hydrogenation of the substrate over these catalytic systems are modeled, and the derived fundamental rate constants are systematically compared. It is found that the differences in activity and product distribution of the reaction over different metal surfaces depend critically on the electronic structures of the metals. From the prospective application of 9-ethyl-carbazole, an effective catalyst should be able to convert the substrate to the fully hydrogenated cis product without forming any kinetically stable intermediates. Ruthenium is the most active catalyst among all the metals studied for this reaction. However, this catalyst suffers from relatively low selectivity with the accumulation of large quantities of partially hydrogenated intermediates due to weak adsorption and poor surface diffusion of the intermediates for further hydrogenation. © 2012 American Chemical Society

Catalytic coupling of CO 2 with epoxide over supported and unsupported amines

Catalytic coupling of carbon dioxide with epoxide to cyclic carbonate is an important reaction that has recently been receiving renewed interest. This route allows the use of carbon dioxide as a greener chemical feedstock, which challenges the current practices for the synthesis of cyclic carbonates and derivatives. The present study is mainly concerned with catalytic coupling reaction between CO(2) and propylene oxide using organic amine as catalyst. The structural aspects of amines and the effects of their immobilization on solid surfaces on reaction kinetics are particularly studied. It is found that 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) amine maintains high catalytic activity both with and without solid support, but other primary amines, such as p-phenylenediamine give much reduced activity when placed on a solid surface. It is attributed to the absence of surface hydrogen in the supported TBD, prohibiting the catalyst sites from CO(2) poisoning. The coupling of other epoxides, including epichlorohydrin and styrene oxide over the solid supported amine, is also briefly carried out. Reaction mechanisms are proposed to explain the experimental observations

Selective oxidation of cyclohexane in supercritical carbon dioxide

A feasibility study into the novel concept of using molecular oxygen to carry out one-step catalytic oxidation of cyclohexane to adipic acid in supercritical carbon dioxide over two types of catalysts, namely Co 2+/Mn2+/NaBr and Ag polyoxometallate, the silver decamolybdodivanadophosphate (Ag5PMo10V2O 40) was carried out. Poor activity and selectivity towards adipic acid were initially noted over the aqueous micellar Co2+/Mn 2+/NaBr catalyst for the cyclohexane oxidation in supercritical carbon dioxide while under comparable conditions, the same catalyst gave a high activity for alkylaromatics oxidation to corresponding acids. It was later found that the adipic acid, being the extremely polar oxidised products, was virtually insoluble in the supercritical phase, which was rapidly degraded to carbon oxides after its prolonged contact with catalyst and O2. Thus, the one-step cyclohexane oxidation to adipic acid with good selectivity can only be achieved by modifying the solvent with acetic acid or methanol, which enabled isolation of the acid from further oxidation. On the other hand, Ag 5PMo10V2O40 , in methanol modified supercritical carbon dioxide gave an impressive selectivity for cyclohexane conversion to other oxygenates. © Springer Science+Business Media, LLC 2007

One step catalytic conversion of cellulose to sustainable chemicals utilizing cooperative ionic liquid pairs

A 100% conversion of cellulose to industrially useful chemicals is, for the first time, achieved in a single pot reaction by the use of cooperative ionic liquid pairs for combined dissolution and catalytic degradation of cellulose, which overcomes the long intrinsic phase problem in the conversion of biomass to chemicals. © 2011 The Royal Society of Chemistry