1,721,049 research outputs found
1H NMR Relaxometric Analysis of Paramagnetic Gd2O3:Yb Nanoparticles Functionalized with Citrate Groups
No full textGd2O3 nanoparticles doped with different amount of Yb3+ ions and coated with citrate molecules were prepared by a cheap and fast co-precipitation procedure and proposed as potential “positive” contrast agents in magnetic resonance imaging. The citrate was used to improve the aqueous suspension, limiting particles precipitation. The relaxometric properties of the samples were studied in aqueous solution as a function of the magnetic field strength in order to evaluate the interaction of the paramagnetic ions exposed on the surface with the water molecules in proximity. The nanoparticles showed high relaxivity values at a high magnetic field with respect to the clinically used Gd3+-chelates and comparable to those of similar nanosytems. Special attention was also addressed to the investigation of the chemical stability of the nanoparticles in biological fluid (reconstructed human serum) and in the presence of a chelating agent
Embedding monomers and dimers of sulfonamide antibiotics into high silica zeolite Y: an experimental and computational study of the tautomeric forms involved
No full textThis work is a second step towards the systematic study of the embedding of sulfonamide antibiotics into a synthetic high silica zeolite Y (HSZ-Y) with hydrophobic properties. In the previous paper [Braschi et al., Langmuir 2010, 31, 9524], the irreversible adsorption from water into HSZ-Y of three sulfonamides was studied by enlightening the host-guest interactions and, in the case of the smallest sized sulfadiazine, the guest-guest interactions of dimeric species inside the zeolite cage. Here the HSZ-Y was loaded with six sulfonamides, namely: sulfanilamide, sulfapyridine, sulfathiazole, sulfadimethoxine, sulfadoxine and sulfamerazine. With the exception of sulfanilamide, which showed scarce affinity for HSZ-Y (maximum loading 3% zeolite dry weight), the other sulfa drugs adsorbed at ca. 28% zeolite dry weight on average, and this is relevant for both water depollution and drug delivery issues. The low affinity of sulfanilamide for HSZ-Y was ascribed to its high hydrophilicity (water solubility 15-40 times higher than other drugs). The most stable tautomeric (amide or imide) form of each antibiotic adsorbed in zeolite Y was proposed by means of IR and solid state NMR spectroscopy augmented by computational modelling. The small dimensions and favourable stabilization energy allow the embedding of imidic and amidic dimers of sulfathiazole and sulfapyridine, respectively, inside the zeolite cage whereas the remaining sulfa drugs adsorbed in monomeric amidic forms
Synthesis of stable ruthenium carbonyl complexes containing alkynols ligands and 2(diphenylphosphino)ethyl-triethoxysilane: novel complexes to anchor on mesoporous silica SBA-15 and Al2O3 surface
No full textReaction of the novel Ru3(CO)10[Ph2P(CH2)2Si(OEt3)]2 complex on SBA-15 and MCM-41 mesoporous silicas
No full textStructure-activity relationships in the partial oxidation of methane to formaldehyde on Fe-x/SiO2 catalysts
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Preparation of luminescent ZnO nanoparticles modified with aminopropyltriethoxy silane for optoelectronic applications
No full textOrgano-modified ZnO nanoparticles: tuning of the optical properties for PLED device fabrication
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Synthesis and Characterization of Lignin-Derived Porous Materials from Phyllostachys edulis (Bamboo Moso) for the Removal of Aromatic Pollutants
Full text linkIn recent decades, pollution from dyes has increasingly attracted the attention of researchers. For this reason, the development of new materials capable of sequestering this type of pollutant has been extensively studied, especially as research using plant biomass to produce new materials. Considerable
attention has been directed toward bamboo moso, which has been the focus of extensive studies. The chemical composition of bamboo culms indicates that cellulose and hemicellulose comprise 65−70%, whereas lignin accounts for 18−30%. In this study, lignin has been extracted from bamboo culms using the hydrothermal methodology under basic conditions. Water-soluble lignin was dispersed in a porogenic organic solvent and polymerized via the Friedel-Craft alkylation reaction. 13C CPMAS NMR spectroscopy was used to study the modification of the water-soluble lignin before and after polymerization; the peaks related to the linker reaction were detected and confirmed the successful cross-linking reaction. The biopolymer-composite was also characterized by FTIR spectroscopy to explore the surface functionality and its interaction with the aromatic molecules, using toluene as a model compound. To gain a deeper understanding of the surface properties, N2 physisorption analysis was performed at 77 K. To evaluate the material’s capacity to act as an adsorbent for organic dyes, the adsorption kinetics of organic pollutants were simulated using Crystal Violet as a model molecule, tracking the adsorption trends through UV−vis spectroscopy. In this context, the adsorption capacity of Crystal Violet was determined to exceed 98% within the initial 4 h period
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