Search results for "X-Ray Diffraction"
showing 10 items of 280 documents
Microwave assisted synthesis and solid-state characterization of lithocholyl amides of isomeric aminopyridines
2011
Microwave (MW) assisted synthesis and solid state structural characterizations of novel lithocholyl amides of 2-, 3-, and 4-aminopyridine are reported. It is shown that the MW technique is a proper method in the preparation of N-lithocholyl amides of isomeric aminopyridines. It offers many advantages compared to conventional heating. The molecular and crystal structures as well as the polymorphic and hydrated forms of prepared conjugates with their thermodynamic stabilities have been characterized by means of high resolution liquid- and solid-state NMR spectroscopy, single crystal and powder X-ray diffraction, and thermogravimetric analysis. Owing to the many biological functions of bile ac…
Surface modification of luminescent lanthanide phosphate nanorods with cationic "Quat-primer" polymers.
2011
"Quat-primer" polymers bearing cationic groups were investigated as a surface modifier for Tb-doped cerium phosphate green-emitting fluorescent nanorods (NRs). The NRs were synthesized by a microwave process without using any complex agents or ligands and were characterized with different analytical tools such as X-ray diffraction, transmission electron microscopy, and fluorescence spectroscopy. Poly(ethyleneimine) partially quarternized with glycidyltrimethylammonium chloride was synthesized separately and characterized in detail. (1)H and (13)C NMR spectroscopic studies revealed that the quaternary ammonium group was covalently attached to the polymer. UV-vis spectroscopy was used to exam…
Nanocomposites of bacterial cellulose/hydroxyapatite for biomedical applications.
2008
In the present work, a nanocomposite material formed by bacterial cellulose (BC) networks and calcium-deficient hydroxyapatite (HAp) powders was synthesized and characterized. The HAp nanoparticles were previously prepared by a wet chemical precipitation method, starting from aqueous solutions of calcium nitrate and di-ammonium phosphate salts. Energy-dispersive spectroscopy reveals that the prepared HAp corresponds to calcium-deficient hydroxyapatite. BC-HAp nanocomposites were prepared by introducing carboxymethylcellulose (CMC) into the bacteria culture media. HAp nanoparticles were then introduced and remained suspended in the culture medium during the formation of cellulose nanofibrils…
Preparation and characterization of a novel chitosan/Al2O3/magnetite nanoparticles composite adsorbent for kinetic, thermodynamic and isotherm studie…
2015
Abstract In this study we developed a novel chitosan/Al 2 O 3 /magnetic iron oxide nanoparticle composite acting as an adsorbent for removing Methyl Orange (MO), a model anionic dye, from aqueous solution. The new adsorbent was characterized by Scanning Electron Microscope (SEM), Thermo Gravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) specific surface area, Energy Dispersive spectrometer (EDAX), powder X-ray Diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) methods. The MO removal by the developed adsorbent was investigated using batch adsorption technique and all parameters influencing the removal efficiency such as: dose of adsorbent, pH and initial MO concentr…
Hierarchical structure and cytocompatibility of fish scales from Carassius auratus
2014
Abstract To study the structure and the cytocompatibility of fish scales from Carassius auratus , scanning electron microscopy (SEM) was used to observe the morphology of fish scales treated with different processing methods. Based on varying morphologies and components, the fish scales can be divided into three regions on the surface and three layers in vertical. The functions of these three individual layers were analyzed. SEM results show that the primary inorganic components are spherical or cubic hydroxyapatite (HA) nanoparticles. The fish scales have an ~ 60° overlapped plywood structure of lamellas in the fibrillary plate. The plywood structure consists of co-aligned type I collagen …
A new biodegradable and biocompatible hydrogel with polyaminoacid structure
2007
The preparation and physicochemical and biological characterization of a novel polyaminoacid hydrogel have been reported. The ,-poly(N-2- hydroxyethyl)-dl-aspartamide (PHEA) has been used as a starting polymer for a derivatization reaction with methacrylic anhydride (MA) to give rise to the methacrylate derivative named PHM. Photocrosslinking of PHM has been performed in aqueous solution at 313 nm and in the absence of toxic initiators. PHM-based hydrogel has been characterized by scanning electron microscopy, X-ray diffractometry, swelling measurements in aqueous media; the degradation of PHM-based hydrogel has been evaluated as a function of time in the absence or in the presence of ester…
Organic solvent vapor effects on phase transition of α and β tegafur upon grinding with solvent additives.
2012
Abstract Solvent effects on α tegafur (5-fluoro-1-(tetrahydro-2-furyl)uracil) phase transition to β tegafur during grinding with solvent additive, as well as phase transition in samples exposed to 95% relative solvent vapor pressure has been studied in this research. Samples containing 0.5% and 0.1% of β tegafur in α and β tegafur mixture, as well as samples of pure α tegafur were ground with different solvent additives, and conversion degrees depending on the solvent were determined using PXRD method. Samples with α and β tegafur weight fraction of 1:1 were exposed to 95% relative solvent vapor pressure, and phase transition rates were determined. Solubility of α tegafur, solvent sorption …
Polymorphism and solvates of flecainide base
2013
Flecainide base is pharmaceutically active substance used for production of flecainide acetate which is known in market as Tambacor, Almarytm, Apocard, Ecrinal or Flecaine. It is determined that flecainide base forms four polymorphic forms abbreviated as Ib, IIb, IIIb and IVb. Flecainide base form Ib is thermodynamically stable form at laboratory temperature while form IIIb is stable at higher temperatures. Flecainide form Ib absorbs water in its structure between layers and forms non-stoichiometric hydrate. Flecainide base binds with organic solvents and form monosolvates. Flecainide base form Ib crystallizes in orthorhombic crystals with lattice parameters a = 27.88 Å, b = 13.78 Å, c = 9.…
Study of Copper Nitride Thin Film Structure
2016
Abstract X-ray diffraction and x-ray absorption spectroscopy at the Cu K-edge were used to study the atomic structure in copper nitride (Cu3N) thin films. Textured nanocrystalline films are obtained upon dc magnetron sputtering on substrates heated at about 190 °C, whereas amorphous films having strongly disordered structure already in the second coordination shell of copper are deposited in the absence of heating.
Structure and composition of sputter-deposited nickel-tungsten oxide films
2011
Films of mixed nickel-tungsten oxide, denoted NixW1-x oxide, were prepared by reactive DC magnetron co-sputtering from metallic targets and were characterized by Rutherford backscattering spectrometry. X-ray photoelectron spectroscopy, X-ray diffractometry and Raman spectroscopy. A consistent picture of the structure and composition emerged, and at x<0.50 the films comprised a mixture of amorphous WO3 and nanosized NiWO4, at x = 0.50 the nanosized NiWO4 phase was dominating, and at x>0.50 the films contained nanosized NiO and NiWO4.