Sharif Digital Repository

We synthesized by electrostatic self-assembly route in basic solution Fe3O4–cysteine/RGO and Fe3O4/RGO–cysteine nanocomposites. In this method, electrostatic interaction was created via negatively charged surface of the reduced graphene oxide and reduced graphene oxide–cysteine sheets and positively charged surface of the Fe3O4 and Fe3O4–Cys nanoparticles in aqueous solution. The structural and magnetic properties of the prepared samples were analyzed by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM), respectively. The dependences of magnetization as a function of... 

In the present study the effect of nanodiamond (ND) on the adsorption capacity of Drug has been investigated. Thermal oxidation nanodiamond (OND) was used as adsorbents for Methotrexate adsorption. The surface properties of NDs were studied by Fourier transform infrared spectroscopy and zeta potential. It was determined that thermal oxidation changed the surface properties of ND, including increase the amount of carboxylic acid groups and decreasing the zeta potential of ND by increasing the thermal oxidation time. The adsorption experiments showed that untreated ND (UND) has large adsorption capacity and fast adsorption kinetic for methotrexate (MTX). These results suggest that the... 

A mechanochemical method was applied to prepare bismuth oxybromide (BiOBr) nanoplates using bismuth nitrate pentahydrate and potassium bromide for 15 (A15), 30 (A30) and 60 (A60) minutes. Scanning electron microscopy studies showed that all the products were comprised of nanoplates. Aggregated nanoplates along with microblocks were observed for A15 and A30 and the entire morphology was not homogenous. The morphology of A60 was uniform and consisted of thin and isolated nanoplates. Evaluation of the X-ray diffraction patterns showed that the purity and crystallinity of the products improved by increasing the milling time. The energy dispersive X-ray analysis confirmed the high purity of the... 

Selective catalytic reduction (SCR) of NOx by NH3 over a series of Mn–M/Z catalysts (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, and Z = the ZSM-5 Zeolite) synthesized by wet impregnation method was investigated. Mn–Fe/Z, Mn–Co/Z, and Mn–Cu/Z catalysts exhibited approximately 100 % NOx conversion over a wide temperature range (200–360 °C) in a defined atmospheric condition, which was noticeably greater than that of Mn–Cr/Z (340–360 °C). Furthermore, the effect of addition of second metal oxide species to the initial Mn/Z catalyst on the structure of catalysts was studied by several characterization techniques. BET measurements revealed high surface area and pore volume of the Mn–Cu/Z catalyst. In... 

VO2(picolinichydrazone) complex as a catalyst was stabilized on a SBA-15 mesoporous silica as a catalytic support by using (3-chloropropyl)triethoxysilane as a connector. SBA-15 is nanoporous and has a high ratio of surface area to volume. The immobilization of a metal–Schiff base complex to the surface area of SBA-15 can improve its catalytic effects by increasing the catalytic surface area. Unlike homogeneous catalysts, heterogeneous catalysts can be recovered and reused several times without any significant loss of catalytic activity. A vanadium–Schiff base complex-functionalized SBA-15 was synthesized by covalency connected by a pre-synthesised VO2(picolinichydrazone) complex to... 

The morphological manipulation and structural characterisation of TiO 2-MgO binary system by an aqueous particulate sol-gel route were reported. Different crystal structures including pure MgTiO 3, mixtures of MgTiO 3 and TiO 2 and mixtures of MgTiO 3 and Mg 2TiO 4 were tailored by controlling Mg:Ti molar ratio and annealing temperatures as the processing parameters. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that all compounds crystallised at the low temperature of 500 °C. Furthermore, it was found that the average crystallite size of the compounds depends upon the Mg:Ti molar ratio as well as the annealing temperature, being in the range 3-5 nm at... 

Abstract : Vertically aligned carbon nanotube (CNT) arrays were synthesized by thermal chemical vapor deposition (CVD) on stainless steel substrates coated by cobalt nanoparticles as catalyst. Morphological and elemental analyses conducted by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) revealed that bamboo-like CNTs were blocked by Co nanoparticles at the tips. The fabricated nanotubes underwent functionalization by electrochemical oxidation in sulfuric acid, and the subsequent structural studies, as well as Fourier transform infrared (FTIR) spectroscopy confirmed that the tips of functionalized CNTs were opened while oxygenated functional groups were... 

The reduced graphene oxide-Fe2O3 (rGO-Fe2O3) nanocomposites were synthesized by a facile and low-cost hydrothermal method employing rGO and Iron (III) nitrate precursors. The synthesis parameters including the reduction time and presence of reduction aid are studied. The structural and morphological studies of the nanocomposites were investigated by using Raman spectra, Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy. The results indicate that Fe2O3 nanoparticles with average particle size of 25 nm are well anchored on graphene sheets and the weight percent of the nanoparticles in the nanocomposites was influenced by the reduction... 

The present study aimed to improve the survivability of L. acidophilus encapsulated in alginate-whey protein isolate (AL-WPI) biocomposite under simulated gastric juice (SGJ) and simulated intestinal juice (SIJ). Microcapsules were prepared based on emulsification/internal gelation technique. Optimal compositions of AL and WPI and their ratio in the aqueous phase were evaluated based on minimizing mean diameter (MD) of the microcapsules and maximizing encapsulation efficiency (EE), survivability of cells under SGJ (Viability), and release of viable cells under SIJ (Release) using Box-Behnken experimental design. Optimal composition comprising 4.54% (w/v) AL, 10% (w/v) WPI, and 10% (v/v)... 

An efficient, green, novel and rapid vortex-assisted dispersive solid-phase extraction (VADSPE) technique was used for the preconcentration and determination of trace levels of Cu2+ followed by flame atomic absorption spectrometry. Graphene oxide (GO) was synthesized from graphite and then modified by pectic acid (poly-d-galacturonic acid, PA) to synthesize the pectic acid–graphene oxide (PA-GO) nanocomposite. The Fourier transform infrared spectrophotometry, field emission scanning electron microcopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were used to characterize the synthesized GO-PA nanocomposite. By using VADSPE technique, PA-GO was used as an adsorbent for... 

The performance of a quartz crystal microbalance (QCM) used as a sensor/detector relies on the performance and quality of the film coated onto the quartz crystal sensor. This study focuses on the sensor coating preparation for the detection of glycine. Cellulose nanofibrils (CNFs), natural polymers, were coated on a quartz crystal (QC) surface by a spin-coating method. The prepared CNF-coated QC was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV), Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR), Raman spectroscopy, and water contact angle (WCA). The stable and fully covered QCs without further... 

Potential effects of folates on the treatment of several human diseases like cognitive function, neural tube defects, coronary heart disease and certain kinds of cancers have been discovered. However, the stability of folic acid against adverse conditions is a great concern. The present study investigates various alginate (A)–pectin (P) gastrointestinal-resistant hydrogel to immobilize folic acid. This involves evaluating different compositions of alginate–pectin to achieve higher encapsulation efficiency and stability during simulated gastric (SG) and simulated intestinal (SI) conditions. Coated alginate hydrogels with pectin resulted significant (p < 0.05) better protection of folic acid... 

The excellent photoluminescent properties of Fe3O4-graphene quantum dots (Fe3O4/GQD) nanoparticles prepared at 30 and 90 °C have made them as promising optical probes for imaging. Herein, the cytotoxicity of GQD and Fe3O4/GQD nanoparticles in L929 cells was investigated using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide] assay. The cellular apoptosis or necrosis was then evaluated by flow cytometry analysis. The Fe3O4/GQD nanoparticles were characterized by transmission electron microscopy (TEM), Raman spectroscopy (Raman), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence (PL). Characterization results obtained, clearly show that Fe3O4/GQD nanoparticles... 

The principal intention of this work is to fabricate and characterize the polyamide/chitosan nanocomposite by a novel single solvent method through the electrospinning procedure. The thermal properties and morphology of prepared nanocomposite are studied by thermogravimetric analysis (TGA) and field-emission scanning electron microscopy (FE-SEM). TGA exposed that the primary decomposition temperature is reduced with rising of chitosan content in the nanocomposites and origin disintegration temperature for polyamide/chitosan nanocomposites is perceived to be in the range from 300 to 500 °C. Also, FE-SEM images demonstrated that the nanofibers of chitosan have good adhesion on the matrix and... 

This research reports the preparation and examination of Cadmium Telluride (CdTe) Quantum Dots and doping CdTe QDs with Europium (Eu), Gadolinium (Gd), and Manganese (Mn) prepared in aqueous solution using TGA as a capping agent. Magnetic QDs (MQDs) are important agents for fluorescence (FL) /magnetic resonance (MR) dual-modal imaging due to their excellent optical and magnetic properties. Herein, the chemical bonds, structural, fluorescence, and magnetized properties of CdTe QDs and effect of Mn, Eu, and Gd ions doping on their properties were examined by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTM), Energy-dispersive X-ray spectroscopy (EDX),... 

Co2+ and Cr3+-substituted SrBaCu2-xCoxCryFe28-yO46 X-type hexaferrite with x = y = 0, 0.1 to 0.5 (step = 0.1) were prepared through auto-combustion sol–gel method and sintered at 1250 °C for 5 h which was found from thermal analysis. The thermal investigation, phase detection, spectral, magnetic, and dielectric characteristics of the prepared composition were investigated by TGA, XRD, FTIR, VSM, and dielectric measurement. XRD patterns of the entire composition confirmed the development of a single phase of X-type structure. The enhancement in the lattice parameters and cell volume was observed by varying the Co–Cr concentration, attributed to the larger ionic radii substitution. FTIRspectra... 

Methicillin resistance Staphylococcus aureus bacteria (MRSA) are serious hazards of bone implants. The present study was aimed to use the potential synergistic effects of Melittin and tetracycline to prevent MRSA associated bone implant infection. Chitosan/bioactive glass nanoparticles/tetracycline composite coatings were deposited on hydrothermally etched titanium substrate. Melittin was then coated on composite coatings by drop casting method. The surfaces were analyzed by FTIR, XRD, and SEM instruments. Tetracycline in coatings revealed multifunctional behaviors include bone regeneration and antibacterial activity. Releasing ALP enzyme from MC3T3 cells increased by tetracycline, so it is... 

The principal intention of this work is to fabricate and characterize the polyamide/chitosan nanocomposite by a novel single solvent method through the electrospinning procedure. The thermal properties and morphology of prepared nanocomposite are studied by thermogravimetric analysis (TGA) and field-emission scanning electron microscopy (FE-SEM). TGA exposed that the primary decomposition temperature is reduced with rising of chitosan content in the nanocomposites and origin disintegration temperature for polyamide/chitosan nanocomposites is perceived to be in the range from 300 to 500 °C. Also, FE-SEM images demonstrated that the nanofibers of chitosan have good adhesion on the matrix and... 

TiO2, transition metal (Cr, Mn, Fe, Co, Ni, Cu, and Zn)- and aluminum-doped TiO2 nanoparticles were prepared by the sol-gel technique. The sulfated catalysts were prepared by the impregnation method with H2SO4 solution. The catalysts were characterised by X-ray diffraction (XRD), BET surface area measurement, diffuse reflectance spectroscopy (DRS), and Fourier transform infrared (FTIR) techniques. The sulfate content of the metal-incorporated samples was considerably higher than for SO4 2-/TiO2. The metal doping brought about a considerable reduction in the extent of sulfate loss from the catalyst surface due to the wide dispersion on the surface. The SO4 2-/TiO2 and SO4 2-/M/TiO2... 

The main aim of the present study was to enhance the degradation capacity of Acid Blue 92 (AB92) by visible-light-active Ag3PO4 nanocomposites based on g-C3N4 and Multiwalled Carbon Nanotubes (MWCNTs). The nanocomposites were fabricated through a tunable in situ deposition method. The properties of the resulting samples were investigated by X-ray diffraction, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity results revealed that the Ag3PO4/g-C3N4 heterojunction inorganic/organic composite exhibited an improvement in both efficiency and the rate of AB92 photodegradation in comparison with the others. The enhanced photocatalytic...