Effect of Ag-doping of nanosized FeMgO system on its structural, surface, spectral, and catalytic properties

The effects of Ag-doping on the physico-chemical, spectral, surface, and catalytic properties of the FeMgO system with various Fe₂O₃ loadings were investigated. The dopant (Ag) molar ratio varied between 0.01 % and 0.05 %. The techniques employed for characterisation of catalysts were TG/DTG, XRD, ESR, N₂ adsorption at ?196°C, and catalytic decomposition of H₂O₂ at 25?C35°C. The results obtained revealed that the investigated catalysts consisted of nanosized MgO as the major phase, apart from the MgFe₂O₄ and/or Fe₃O₄ phases. ESR result of the FeMgO system revealed the presence of paramagnetic species as a result of Ag-doping. The textural properties including SBET, porosity and St were modified by Ag-doping. The doping process with Ag-species improved the catalytic activity of the FeMgO system. Increasing the calcination temperature from 400°C to 800°C increased the catalytic activity (k*_{30 °C}) of 0.05 AgFeMgO in H₂O₂ decomposition by 21.2 times.     

Comparison of dry reforming of methane in low temperature hybrid plasma-catalytic corona with thermal catalytic reactor over Ni/γ-Al2O3

In the current study,the hybrid effect of a corona discharge and γ-alumina supported Ni catalysts in CO2 reforming of methane is investigated.The study includes both purely catalytic operation in the temperature range of 923-1023K,and hybrid catalytic-plasma operation of DC corona discharge reactor at room temperature and ambient pressure.The effect of feed flow rate,discharge power and Ni/γ-Al2O3 catalysts are studied.When CH4/CO2 ratio in the feed is 1/2,the syngas of low H2/CO ratio at about 0.56 is obtained,which is a potential feedstock for synthesis of liquid hydrocarbons.Although Ni catalyst is only active above 573K,presence of Ni catalysts in the cold corona plasma reactor(T≤523K) shows promising increase in the conversions of methane and carbon dioxide.When Ni catalysts are used in the plasma reaction,H2/CO ratios in the products are slightly modified,selectivity to CO increases whereas fewer by-products such as hydrocarbons and oxygenates are formed.     

Detection of multilayered media in the acoustic waveguide

This work is concerned with the inverse problem for ocean acoustics modeled by a multilayered waveguide with a finite depth. We provide explicit formulae to locate the layers, including the seabed, and reconstruct the speed of sound and the densities in each layer from measurements collected on the surface of the waveguide. We proceed in two steps. First, we use Gaussian type excitations on the upper surface of the waveguide and then from the corresponding scattered fields, collected on the same surface, we recover the boundary spectral data of the related 1D spectral problem. Second, from these spectral data, we reconstruct the values of the normal derivatives of the singular solutions, of the original waveguide problem, on that upper surface. Finally, we derive formulae to reconstruct the layers from these values based on the asymptotic expansion of these singular solutions in terms of the source points.     

A Mild Method for the Protection of Aldehydes as Dithioacetals and Dithiolanes Catalyzed by I2 Generated in Situ Using Fe(NO3)3.9H2O/NaI Under Heterogeneous Conditions

Structurally diverse aromatic aldehydes were thioacetalated in a clean and efficient reaction with ethane‐1, 2‐dithiol and thiophenol based on the use of I₂ generated in situ from Fe(NO₃)₃.9H₂O/NaI. The reaction occurs in good to high yield in dichloromethane at room temperature and the use of toxic and corrosive molecular iodine is avoided.     

Impact of chitosan coating of anionic liposomes on clearance rate, mucosal and systemic immune responses following nasal administration in rabbits

Liposomes have been identified as effective immunological adjuvants and have potential for the intranasal and oral delivery of protein antigen. Anionic MLV liposomes were prepared by dehydration–rehydration method. For coating, liposomes were incubated in chitosan solution. Efficiency of coating was confirmed by the evaluation of FITC-labelled chitosan-coated liposomes using a fluorescent microscope. Liposomes morphology and size were studied by optical microscope and size analyzer. Mucoadhesion potential of liposomes was evaluated in human nose by gamma-scintigraphy using ^99mTc-labelled liposomes. Rabbits (4 animals per group) were nasally immunized in weeks 0, 2 and 4 by liposomes encapsulated with 40 Lf TT. Bleedings and lavage collections were taken place in weeks 3 and 6, and IgG and sIgA titers were measured by ELISA method.Liposomes had a mean diameter of 2.38 μm. Loading of TT was 58.7 ± 12.4%. The mucoadhesion (clearance rate from nose) of both coated and non-coated liposomes was similar (P > 0.05). Among the immunized animals, the highest nasal lavage sIgA titers were seen in non-coated liposomes followed by coated ones. The serum IgG titers (2nd bleeding) in animals immunized by both kinds of liposome were similar (P > 0.05), and were lower than the TT solution group (P < 0.05). Immunization by i.m. injection of TT solution resulted in the lowest sIgA and highest IgG titers (P < 0.05) compared with liposomal groups.The results were indicative of good potential of negatively charged liposomes in the induction of mucosal immunity. Coating of liposomes by chitosan, failed to increase both the residence time of liposomes in nasal cavity and systemic responses. Conversely, coated liposomes could not induce the mucosal responses as efficiently as non-coated liposomes. It seems that the coating of liposomes affected their interaction potential with nasal associated lymphoid tissue cells.     

Poly[2-(N,N-Dimethylamino) Ethyl Methacrylate] /Poly(Styrene-Co-Methacrylic Acid) Interpolymer Complexes

Summary: Poly[2-(N,N-dimethylamino)ethyl methacrylate] (PDMAEMA), copolymers of different compositions of styrene with 2-(N,N-dimethylamino)ethyl methacrylate (SDMAEMA) or methacrylic acid (SMA) were synthesized by free radical polymerization and characterized by several techniques. Different ternary mixtures containing proton-acceptors PDMAEMA or SDMAEMA, proton-donor copolymers SMA and a solvent (butan-2-one or THF) were prepared. The present study, that investigated several factors that affected the phase behaviors of the ternary mixtures above, confirmed that, indeed depending on the nature of solvent, densities of interacting species, amounts of efficient specific interactions that occurred between the two copolymers, interpolymer complexes of different structures were elaborated. The complexation phenomena, observed with these different systems were analyzed in solution by viscometry that confirmed these effects in monitoring the formation of interpolymer complexes. The specific interactions that occurred between pairs of polymers of each system above were qualitatively evidenced by FTIR spectroscopy from the appearance of new bands or their new redistribution. The glass transition temperature Tg of the obtained complexes of different structures determined by DSC varied differently with the weight fraction of one of the copolymers. These various Tg-compositions were analyzed using the Kwei and Brostow et al. approach recently developed. Thermal analysis of some of the elaborated complexes, examined by thermogravimetry, confirmed their improved thermal stability.     

Organic synthesis and biological evaluation of novel “3 + 1” mixed ligands of technetium-99m Gabapentin as receptor imaging agents

This work focuses on the “3 + 1” mixed ligands of ^99mTc labeled Gabapentin as α2δ receptor imaging agents in the brain. Gabapentin 1-(aminomethyl)cyclohexanacetic acid as monodentate and two tridentates: tridentate A; 3-(2-imino-thiozolidin-4-one)-quinozoline-4-(3H)-one and tridentate B; N-(4-chlorophenyl)-2-imino-2H-chromene-3-Carbothioamide which were synthesized and characterized by infrared analysis (IR), ¹H nuclear magnetic resonance (NMR), and mass spectrum. ^99mTc-complexes were prepared by the “3 + 1” mixed ligand approach. The labeling conditions were optimized and the complexes was extracted by chloroform and purified by high performance liquid chromatography. ^99mTc-complexs were lipophilic and stable for at least 8–12 h at room temperature. The biodistribution of the ^99mTc-complexes was evaluated in mice. The brain uptake was 4.5% and 3.5% ID/g (percentage of the injected dose per gram) at 5 min, and the retention was 1.5% and 1.7% ID/g at 120 min for ^99mTc-complex A and ^99mTc-complex B, respectively.     

p-Toluenesulfonyl chloride as a new and effective catalyst for acetylation and formylation of hydroxyl compounds under mild conditions

<正>The catalytic application of p-toluenesulfonyl chloride for efficient acetylation of various types of alcohols and phenols with acetic anhydride in solvent-free conditions is reported.Also structurally diverse alcohols were formylated using formic acid based on the use of catalytic amount of p-toluenesulfonyl chloride under solvent-free condition.The reactions were carried out in short reaction time and in good to excellent yields at room temperature.