Study of the productivity of MWCNT over Fe and Fe–Co catalysts supported on SiO2, Al2O3 and MgO

AbstractIn the present study, multi-walled carbon nanotubes (MWCNT) were prepared in good quality and quantity, MWCNT were produced using the catalytic chemical vapor deposition (CCVD) technique and the carbon source was acetylene. Different catalysts were synthesized based on iron and a mixture of iron and cobalt metal supported on SiO2, Al2O3 or MgO. The effect of parameters such as iron concentration, support type, bimetallic catalyst and the method of catalyst preparation has been investigated in the production of MWCNT. The quality of as-made nanotubes was investigated by the high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis (TGA). The best yield of MWCNT was 30 times of the amount of the used catalyst. The high yield of MWCNT was gained by 40wt.% Fe on alumina support which was prepared by the sol–gel method. TEM analysis was done for the carbon deposit, which revealed that the walls of the MWCNT were graphitized, with regular inner channel and uniform diameter. It reflected a reasonable degree of purity. The TGA showed that MWCNT was decomposed at 635°C by a small rate indicating a high thermal stability and well crystalline formation of the produced MWCNT

NANOEMULSION AS A NOVEL OPHTHALMIC DELIVERY SYSTEM FOR ACETAZOLAMIDE

Objective: The aim of this work was to formulate the antiglaucoma drug acetazolamide as ocular nanoemulsion of high therapeutic efficacy and prolonged effect. Methods: Eighteen nanoemulsion formulaions consisting of different oils, surfactants and cosurfactants at various ratios and constant water content (39%) were prepared based on their constructed pseudoternary-phase diagrams. According to the In vitro release studies, three nanoemulsions which exhibited fast drug release were used to prepare acetazolamide nanoemulsions with higher water content (59%). The six nanoemulsions at either water content (39 or 59%) were evaluated for their physicochemical properties and ex- vivo corneal permeability. In addition, Draize rabbit eye irritation test was performed. Moreover, biological evaluation of acetazolamide nanoemulsions for their intraocular pressure lowering activity on glaucomatous albino rabbits was carried out. Results: Isopropyl myristate nanoemulsion prepared with cremophor EL and transcutol P exhibited the fastest drug release among all isopropyl myristate nanoemulsions. Oleic acid nanoemulsion prepared with mixture of tween 80 and cremophor EL as surfactants together with transcutol P showed the fastest drug release among other oleic acid nanoemulsion formulae. Similar results were also observed for peanut oil nanoemulsions. The above mentioned formulations either at 39% or 59% water content showed acceptable physicochemical properties and higher acetazolamide permeability coefficient through goat corneas than that reported for the free drug. They also were non irritant to rabbit eye. Therapeutic efficacy testing revealed that peanut oil nanoemulsion at 39% water content showed better and prolonged intraocular pressure lowering effect relative to either commercial brinzolamide eye drops (Azopt®) or the commercial oral acetazolamide tablet (Cidamex®). Conclusion: Acetazolamide was successfully formulated in nanoemulsion form which revealed high therapeutic efficacy in treatment of glaucoma together with a prolonged effect

The family Carditidae (Bivalvia) in the early Danian of Patagonia (Argentina)

The first systematic analysis of the Danian carditids of Patagonia is presented, which includes four genera—one new genus and the first records of three other genera in South America. They consist of Claibornicardia paleopatagonica (Ihering, 1903), a widely distributed species occuring in the Jagüel, Roca and Salamanca formations (Neuquén, Río Negro and Chubut Provinces); Rotundicardia Heaslip, 1968, represented by the new species R. mariobrosorum n. sp., which is restricted to the Roca Formation (Río Negro Province); Cardites feruglioi (Petersen, 1846) (Roca and Lefipán formations, Río Negro and Chubut Provinces); and by Kalelia new genus, which includes K. burmeisteri (Böhm, 1903) from the Salamanca and Roca formations (Río Negro and Chubut Provinces), which is related to the Paris Basin species K. multicostata (Lamarck, 1806) n. comb. and K. pectuncularis (Lamarck, 1806) n. comb. ‘Venericardia’ iheringi (Böhm, 1903), a species known only from internal molds, is described and regarded as a carditid with uncertain affinities. The presence of Claibornicardia, Rotundicardia, and Cardites in Patagonia constitutes the most ancient record of these genera and confirms biogeographical connections previously established between the Danian Argentinian and North American/European fossil faunas.Fil: Perez, Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: del Río, Claudia Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentin

On the occurrence of Campanian rudist biostrome, Aruma Formation, Central Saudi Arabia

780-784The lower limestone Khanasir Member of the Aruma Formation in central Saudi Arabia is characterized by Campanian rudist biostrome at its uppermost part. The most abundant rudist fauna are Eodictyoptychus arumaensis, Durania sp. and Biradiolites sp. Succession is overlying continental siliciclastics of Wasia Formation and comprises shale at the base followed by slightly dolomitized, burrow, nodular limestone and caps with rudist biostrome. Abundant microfacies types are wackestones, packstones, grainstones and floatstones with green algae, benthic foraminifers. The succession in general, indicated shallowing upward sequence and rudist biostrome represents a shallow marine lagoonal environment