Publication Date: 2016
Materials Chemistry and Physics (02540584)183pp. 136-144
Alumina/yttria nanocomposite powder as an yttrium aluminum garnet (YAG) precursor was synthesized via partial wet route using urea and ammonium hydrogen carbonate (AHC) as precipitants, respectively. The products were characterized using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectroscopy. The use of urea produced very tiny spherical Y-compounds with chemical composition of Y2(CO3)3·nH2O, which were attracted to the surface of alumina nanoparticles and consequently, a core-shell structure was obtained. The use of ammonium hydrogen carbonate produced sheets of Y-compounds with chemical composition of Y(OH)CO3 covering the alumina nanoparticles. A fine-grained YAG ceramic (about 500 nm), presenting a non-negligible transparency (45% RIT at IR range) was obtained by the spark plasma sintering (SPS) of alumina-yttria nanocomposite synthesized in the urea system. This amount of transmission was obtained by only the sintering of the powder specimen without any colloidal forming process before sintering or adding any sintering aids or dopant elements. However, by spark plasma sintering of alumina-yttria nanocomposite powder synthesized in AHC system, an opaque YAG ceramic with an average grain size of 1.2 μm was obtained. © 2016 Elsevier B.V.
Publication Date: 2016
Radiation Measurements (13504487)89pp. 14-22
In this study, lithium-tetraborate (LTB) was synthesized by three methods of high-temperature solid state, wet and combustion reactions. Copper was added to pure LTB by solution assisted method, to improve the thermoluminescence (TL) properties. The pellets of LTB were produced using pressing and sintering operations at 850 °C. The synthesized LTB pellets, exposed to the gamma radiation of 60Co source in the dose range of 5-20Gy and glow curves as well as dose-response diagrams were obtained. Ultimately, the effects of different factors on TL behaviors like dopant, crystallite size and particle morphologies were studied. The results show that between pure samples, LTB which synthesized by combustion method has higher TL sensitivity than those of other methods. However, it was seen a weak glow peak for 5Gy, due to the nanocrystalline structure of LTB. This property led to decrease TL intensity at low-doses and postponed saturation at high-doses. Fading of this sample was also less than others and has relatively better reproducibility. Among LTB:Cu pellets which synthesized by the wet reaction showed the higher TL response than others due to the creation of more traps and luminescence centers and had promising properties in the case of dose response linearity and fading. © 2016 Elsevier Ltd. All rights reserved.
Publication Date: 2016
Analytical Methods (17599679)8(39)pp. 7247-7253
In this work, a highly sensitive aptasensor for digoxin determination in biological samples has been introduced. The surface of a gold screen-printed electrode was modified by using electrodeposited gold nanoparticles (GNPs). A monolayer of 3-mercaptopropionic acid (MPA) was then self-assembled on the GNP surfaces. Subsequently, an amino-labeled digoxin specific aptamer was covalently bonded to the carboxylic groups of MPA on the GNPs through imide bond formation. The silver nanoparticle decorated graphene oxide (AgNPs-GO) interacted with the immobilized aptamer via π-π interaction and the oxidation signal of AgNPs was monitored. In the presence of digoxin, the hybrid left the electrode surface due to the specific interaction between the aptamer and digoxin, and the oxidation signal decreased. The proposed aptasensor delivered a linear dynamic range of 1 pM to 0.1 μM and a detection limit of 0.3 pM and was successfully utilized for digoxin determination in biological samples with good reliability. © The Royal Society of Chemistry 2016.
Publication Date: 2015
IEEE Sensors Journal (1530437X)15(11)pp. 6454-6459
Here, a generalized induction coil sensor model (more generalized than other models) has been considered at low frequencies (within 0.1-100 Hz), and the equivalent magnetic field of the coil's thermal noise and the sensor's signal-to-noise ratio (SNR) were calculated theoretically based on the dimensions and geometry of the coil winding and its core. In our suggested theoretical consideration, all involved parameters were considered and optimized without any assumption and constraint, while some authors in their latest reports, have been used some assumptions and constraints in their sensor calculations (such as holding constant the sensor's volume and aspect ratio). Our calculations indicated that the equivalent magnetic field of the thermal noise can be minimized by the coil-to-core weight ratio. Moreover, it was found that the sensor's SNR can be maximized with only a special value of core aspect ratio (length to diameter of core ratio). The obtained theoretical results were evaluated experimentally by fabricating a search coil magnetometer model, using the optimum parameters. The resonance frequency and the parasitic capacitance of the coil were measured. Moreover, the variations of the transfer function of the magnetometer, with respect to frequency, were studied. Thus, it was shown that, at low frequencies, our experimentally measured noise data exhibit better agreement with our suggested theoretical results with respect to the state of the art. © 2001-2012 IEEE.
Publication Date: 2013
Journal of Electroanalytical Chemistry (15726657)703pp. 146-152
We describe here the covalent modification of glassy carbon electrode with nile blue (NB), a redox dye, by electrochemical reduction of its corresponding diazonium salt, which is generated in situ from the reaction between the aromatic amino phenyl group of NB and sodium nitrite. NB is attached directly to the electrode surface without any cross linking agent or complex matrices. This modification method is very rapid, simple, in one step and provides a very stable grafted NB film. Cyclic voltammetry and electrochemical impedance spectroscopy were used to trace the reaction. The resulting NB films have a very stable and reversible electrochemical response and exhibit excellent electrocatalytic behavior toward hydrogen peroxide and oxygen reduction. The amperometric detection of hydrogen peroxide is performed at -0.15 V vs. Ag/AgCl. This strong catalytic effect for reduction of hydrogen peroxide and oxygen exhibited a biocompatible platform for development of glucose biosensors. Therefore, a glucose biosensor is developed using glucose oxidase by simple casting method based on decreasing of cathodic peak current of oxygen. This biosensor has been successfully applied to determination of glucose in human plasma sample. The great stability and reusability, excellent electrochemical reversibility, technically simple and possibility of preparation at short period of time make this method suitable for low-cost bioelectronical devices. © 2013 Elsevier Ltd. All rights reserved.
Publication Date: 2013
Electrochimica Acta (00134686)112pp. 640-647
This study reports a novel, simple and fast approach for construction of a highly stable glucose biosensor based on the immobilization of glucose oxidase (GOx) onto a glassy carbon electrode (GCE) electrografted with 4-aminophenyl (AP) by diazonium chemistry. Aminophenyl was used as cross-linker for covalent attachment of glucose oxidase to the electrode surface. Cyclic voltammograms of the GOx-modified GCE in phosphate buffer solution exhibited a pair of well-defined redox peaks, attesting the direct electron transfer (DET) of GOx with the underlying electrode. The proposed biosensor could be used to detect glucose based on the consumption of O2 with the oxidation of glucose catalyzed by GOx and exhibited a wide linear range of glucose from 0.05 mM to 4.5 mM and low detection limit of 10 μM. The surface coverage of active GOx, heterogeneous electron transfer rate constant (ks) and Michaelis-Menten constant (KM) of immobilized GOx were 1.23 × 10-12 mol cm-2, 4.25 s-1 and 2.95 mM, respectively. The great stability of this biosensor, technically simple and possibility of preparation at short period of time make this method suitable for fabrication of low-cost glucose biosensors. © 2013 Elsevier Ltd. All rights reserved.
Publication Date: 2021
Bioelectrochemistry (15675394)140
Regarding the cancer fatal consequences, early detection and progression monitoring are the most vital issues in patients’ treatment and mortality reduction. Therefore, there is a great demand for fast, inexpensive, and selective detection methods. Herein, a graphene-based aptasensor was designed for sensitive human breast cancer cell detection. A reduced graphene oxide-chitosan-gold nanoparticles composite was used as a biocompatible substrate for the receptor stabilization. The significant function of the aptamer on this composite is due to the synergistic effects of the components in improving the properties of the composite, including increasing the electrical conductivity and effective surface area. After the aptasensor incubation in MCF-7 cancer cells, the cell membrane proteins interacted specifically with the three dimensional-structure of the AS1411 aptamer, resulting in the cell capture on the aptasensor. The aptasensor fabrication steps were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The higher cell concentrations concluded to the higher captured cells on the aptasensor which blocked the Ferro/Ferricyanide access to the sensor, causing increases in the charge transfer resistances. This aptasensor shows a linear relationship with the cell concentration logarithm, high selectivity, a wide linear range of 1 × 101–1 × 106 cells/mL, and a low detection limit of 4 cells/mL. © 2021 Elsevier B.V.
Torabian n., N.,
Ziaei-rad s., S.,
Jafari, M.,
Dini, G. Publication Date: 2016
Metallography, Microstructure, and Analysis (21929262)5(2)pp. 85-94
In this paper, a dislocation density-based finite element model is developed to study the behavior of twinning-induced plasticity (TWIP) steels in which mechanical twinning plays a significant role in the plastic deformation process. The model is calibrated for Fe-31Mn-3Al-3Si TWIP steel using experimental data. Comparison of the computational results with experimental observations suggests that the numerical model acceptably predicts the macroscopic behavior and the twinning content of the material. Next, the developed numerical model is employed to investigate some microstructural characteristics of the material. The effect of grain size on twinning is also studied. In addition, different loading conditions on a representative volume element are considered to reveal the existence of any relationship between twinning and triaxiality. © 2016, Springer Science+Business Media New York and ASM International.
Publication Date: 2015
RSC Advances (20462069)5(94)pp. 77255-77263
Nowadays, iron oxide nanoparticles are among the most interesting carriers in simultaneous drug delivery and magnetic resonance imaging applications (theranostics). In this study, Fe3O4 magnetic nanoparticles were synthesized by a co-precipitation method followed by coating with an active-bioglass layer. This nanostructure is functionalized with hyperbranched polyglycerol through ring-opening polymerization of glycidol. The carrier was characterized using TEM, FT-IR, XRD, TGA, and elemental analysis. The results showed that the diameter of the carrier was between 20-30 nm. The cytotoxicity and cellular uptake results indicated that this nanostructure did not induce any cytotoxicity while expressing good potential as a contrast agent for magnetic resonance imaging. Moreover, curcumin was loaded on the carrier as a hydrophobic sample drug. The results showed a significant increase in curcumin solubility, which revealed the potential of this nanostructure in simultaneous cancer diagnosis and therapy. © 2015 The Royal Society of Chemistry.
Publication Date: 2021
Separation and Purification Technology (13835866)275
An extraction-electrooxidation (E-EODS) system is introduced for the removal of dibenzothiophene (DBT) from model fuel (DBT in n-hexane). The process is run in an electrochemical cell as a batch reactor, where, the model fuel is in contact with an appropriate immiscible polar solvent composed of acetonitrile and water (MeCN-water, 90:10% v/v) that serves as both the extraction solvent and electrochemical medium. The electrochemical oxidation of DBT, which is extracted into the MeCN-water phase, enhances the continuous removal of DBT from the model fuel phase. The effects of the composition of the extraction solvent, applied potential and the process time on DBT removal efficiency are assessed. The results indicate that with the selection of the MeCN-water, 90:10 v/v in a 1:1 ratio respect to the model fuel, this extraction method yields about 100% extraction efficiency within 5 h, at 25 °C at 2.9 V and atmospheric pressure as determined by HPLC technique. Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy, and gas chromatography-mass spectrometry (GC–MS) techniques are applied to identify the electrochemical oxidation products of DBT. The electrochemical oxidation-derived extraction process through this method is innovative and feasible for deep desulfurization of liquid fossil fuels. © 2021
Publication Date: 2020
Iranian Journal of Science and Technology - Transactions of Mechanical Engineering (22286187)44(4)pp. 1091-1102
In this paper, the relationship between the cutting conditions and the wear mechanisms in turning Inconel718 from both modeling and experiment points of view has been studied. The tool chosen consists of a hard fine-grained WC with 6% Co with TiAlN layer. As a result, the recommended machining conditions with minimal wear would be the selection of a tool with a radius of 1.6 mm and the cutting velocity in the range of 45 to 55 m/min. The optimal variables obtained from artificial neural networks and genetic algorithm are found to be in good agreement with the results of laboratory findings on the wear mechanism map. Also, the results showed that at lower cutting velocities and feed rates, the TiAlN layer acts to prevent the transfer of elements between the tool and workpiece (mild and transient wear zones), causing the turning forces to stabilize over time. However, with an increase in the cutting velocity and feed rate (severe zone), the TiAlN layer breaks off the tool surface resulting in a considerable increase in the friction coefficient, cutting forces, and the adhesive wear. The main reason for this phenomenon is the transfer of elements such as nickel, chrome, and iron to the flank face. © 2019, Shiraz University.
Publication Date: 2015
Applied Surface Science (01694332)357pp. 1758-1764
In the present study, bioactive glass (BG), carbon nanotube (CNT), and chitosan (Cs) were used with different ratios for the fabrication of nanocomposite scaffold for bone tissue engineering. BG was synthesized by sol-gel process and CNT was functionalized by immersing in sulfuric acid as well as nitric acid. Nanocomposite scaffold was produced using a novel technique, hot press, and salt leaching process and cross-linked by Hexamethylene diisocyanate (HDI). The optimum porosity of the scaffold with respect to the ratio of salt and precursor was kept around 70%. Mechanical properties of the scaffolds were increased by the addition of CNT and hence, the compressive strength of them with 4 wt% CNT was increased up to 5.95 ± 0.5 MPa. The nanocomposite scaffolds were characterized by FT-IR, SEM, XRD, and electrochemical analysis. Furthermore, scaffolds were immersed in PBS for evaluating the biodegradability, water absorption, and CNT release. The results indicated that water absorption of the scaffolds was increased by adding CNT to the scaffold. The amount of released CNT after 30 days was measured within 6 × 10 -4 and 1 × 10 -3 mg/ml. Attachment and proliferation of MG63 osteoblast cell line on Cs/BG/CNT scaffolds were investigated by MTT assay indicating no toxicity for this nanocomposite scaffolds. According to the results of the experiments, the nanocomposite scaffold with modified composition (Cs/BG/CNT, 80:20:2 wt%) was the best one in matters of mechanical, chemical, and cellular properties and also the most appropriate for trabecular bone tissue. © 2015 Elsevier B.V. All rights reserved.
Publication Date: 2013
Journal of Electroanalytical Chemistry (15726657)704pp. 249-254
In this work, a new organic-inorganic hybrid compound containing N,N′-bis(salicylidene)-1,2-phenylenediaminocobalt (III) (CoSal) complex and a Keggin type polyoxometalate, H4SiW12O40 (SiW12), has been synthesized and characterized. FT-IR spectra showed the presence of both species, UV/Vis spectra displayed the interaction between CoSal and POM in the hybrid compound and XPS determined the oxidation states of cobalt in CoSal and in the hybrid compound. Elemental (CHN) and thermogravimetry analyses showed that 4 mol of CoSal complex react with one mole of SiW 12 to form (CoSal)4SiW12. This compound was used as a bulk-modifier to fabricate the chemically modified carbon paste electrode (CPE) by direct mixing. The electrochemical behavior and electrocatalysis of bulk modified CPE was studied in 1MH2SO 4 acidic solution by cyclic voltammetry in detail. The results indicate that the modified electrode has a notable bifunctional catalytic activity. It reduces iodate and this property is attributed to the function of SiW12; on the other hand, it oxidizes cysteine due to the function of the CoSal complex. Analytical features of the sensor for amperometric determination of iodate and cysteine were also evaluated. The sensor has a good stability; moreover, it can be renewed easily and repeatedly through a mechanical polishing process. These properties make the modified CPE a good candidate to act as a bifunctional electrocatalyst and an electrochemical sensor as well. © 2013 Elsevier Ltd.
Publication Date: 2006
Adsorption Science and Technology (02636174)24(6)pp. 487-496
Natural and modified clinoptilolite were used to remove zinc and cadmium ions from aqueous solution. The raw material was characterized by XRD and XRF analysis. Clinoptilolite was modified with benzyldimethyltetradecylammonium chloride (BDTA) to increase the adsorption of neothorin [2-(2-arsenophenylazo)chromotropic acid disodium salt, C10H11AsN2Na2 O11 S2]. All experiments were undertaken using a continuous method. The ultimate goal of these studies was the selective removal of trace amounts of Cd(II) and Zn(II) ions from aqueous solution using a modified form of clinoptilolite. The results obtained showed that Cd(II) and Zn(II) ions were adsorbed quantitatively onto modified clinoptilolite over the respective pH ranges of 4.0-5.4 and 3.3-4.5. The influence on the adsorption process of various parameters such as the ionic concentration, the flow rate, the particle size, the pH value and the presence of other cations was studied to obtain the optimum conditions. Although clinoptilolite and its surfactant-modified form were not capable of the selective adsorption of the cations studied, on the basis of the results obtained it was possible to selectively remove Zn(II) and Cd(II) ions from aqueous solution by modified clinoptilolite using a two-step process, i.e. initial treatment with BDTA followed by treatment with neothorin.
Publication Date: 2016
Journal of Polymer Research (15728935)23(12)
The main objective of this study was to prepare thin film nanofibrous composite (TFNC) membranes based on self-support nanofibrous mats. To this end, polyethylene terephthalate nanofibrous supports were produced by electrospinning technique and subsequently heat treatment was performed to increase mechanical stability of the mats. Then, interfacial polymerization procedure was applied for preparation of TFNC nanofiltration membranes. For comparison, the thin film composite (TFC) nanofiltration membrane was prepared by the same conditions based on polyethersulfone ultrafiltration membrane prepared through phase inversion method. Chemical structure, morphology and mechanical properties were studied by using ATR-FTIR, SEM and tensile tests, respectively. Also, filtration performance was investigated by water flux, rejection, water contact angle and MWCO determination. Results showed that the TFNC nanofiltration membrane had higher salt rejection and four times higher water flux than the TFC nanofiltraion membrane (Na2SO4 rejection and pure water flux were (93 ± 3)%, (34 ± 2.3) L./m2h and (67 ± 4)%, (8 ± 0.9) L./m2h for TFNC and TFC, respectively). At the end, the filtration performance of PET TFNC-NF membrane was compared with other nanofibrous nanofiltration membranes. [Figure not available: see fulltext.] © 2016, Springer Science+Business Media Dordrecht.
Publication Date: 2024
Polymers for Advanced Technologies (10427147)35(1)
In this study, MIL-101 (Cr) and NH2-MIL-101 (Cr) nanoparticles were synthesized by hydrothermal method. Butyl acrylate-styrene copolymer was used along with these nanoparticles to improve the mechanical properties of epoxy adhesive. The results of the Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) test showed that the synthesis and functionalization of the metal organic framework (MOFs) were successful. The mechanical properties and adhesion features in the lap joint bonding of aluminum foil to the aluminum foil of modified epoxy adhesives were investigated by tensile and lap shear tests. The results of the tensile test showed that by adding 0.3 wt% of NH2-MIL-101 (Cr) and 2.5 wt% of poly(butyl acrylate-block-styrene) to epoxy adhesive, the tensile strength, modulus and toughness of dumbbell samples were increased up to 34.46%, 31.74% and 58.53%, respectively. Furthermore, based on the lap shear test results, by adding 0.3 wt% NH2-MIL-101 (Cr) along with 2.5% poly(butyl acrylate-block-styrene) to the epoxy adhesive, the lap shear strength of samples increased from 1.05 ± 0.08 MPa to 5.25 ± 0.06 MPa compared to the neat epoxy adhesive. According to the TGA test, the highest thermal stability is related to the sample containing 0.3 wt% of NH2-MIL-101 nanoparticles and 2.5 wt% of the copolymer. The image of the fracture surface of the sample containing 0.3 wt%. NH2-MIL-101 (Cr) and 2.5 wt% block copolymer shows that the interface of nanoparticles and the matrix improved due to the chemical reaction of functional groups of nanoparticles and adhesive matrix. © 2023 John Wiley & Sons Ltd.
Publication Date: 2026
Talanta (00399140)297
Equine herpesvirus type 1 (EHV-1) is a globally prevalent equine pathogen responsible for severe respiratory, neurological, and reproductive disorders. Accurate and ultrasensitive detection of EHV-1 is critical for timely disease management. In this study, we report the development of the first G-quadruplex-forming aptamer specifically designed for EHV-1 detection. The aptamer was generated using an in silico approach, and its G-quadruplex conformation was confirmed using circular dichroism (CD) spectroscopy and crystal violet fluorescence assays. Binding affinity and specificity were assessed using a comprehensive panel of analytical techniques, including colorimetric assays, enzyme-linked apta-sorbent assay (ELASA), surface plasmon resonance (SPR), CD spectroscopy, and fluorescence analysis. The aptamer exhibited a high binding affinity in the picomolar range, as determined by SPR. In both colorimetric and ELASA platforms, it enabled the detection of as few as 10 viral particles per milliliter, compared to the 1000 viral particles per milliliter required by conventional PCR. ELASA results demonstrated excellent diagnostic performance, yielding an area under the curve of 0.96. Importantly, this aptamer-based method eliminates the need for DNA extraction, primers, or gel electrophoresis. These findings underscore the aptamer's strong potential as a cost-effective, rapid, and user-friendly point-of-care diagnostic tool for EHV-1, especially in low-resource or field settings. © 2025 Elsevier B.V.
Publication Date: 2018
Journal of Immunological Methods (00221759)458pp. 26-32
Hepatitis B virus (HBV) infection is the major public health problem leading cause of death worldwide. The most important diagnostic marker for this infection is hepatitis B surface antigen (HBsAg). In this study, a novel, inexpensive, portable and sensitive ELISA method was designed and investigated for diagnosis of HBsAg based on the functionalized Fe3O4 and Al2O3 nanoparticles, with the strategy for detecting the concentration of glucose using a cheap and accessible personal glucose meter (PGM). The ELISA system was constructed using hepatitis B antibody against HBsAg immobilized on streptavidin coated magnetic iron oxide particles (S-Fe3O4) as the capture antibody (Ab1). In addition, another hepatitis B antibody against different epitope of HBsAg (Ab2) and glucoamylase both were immobilized on Al2O3 nanoparticles. After formation of the sandwich immune complex between Ab1 and Ab2 immobilized on S-Fe3O4 and Al2O3 NPs, respectively, through HBsAg, starch was converted into glucose using glucoamylase. Then, the glucose concentration was measured using PGM. The concentration of HBsAg was calculated based on the linear relation between the concentrations of HBsAg and glucose. Under optimal conditions, this assay showed detection limit values of 0.3 to 0.4 ng ml−1 for “ay” and “ad” subtypes of HBsAg, respectively. The results indicate that the designed assay is comparable to the commercial kits in terms of sensitivity, on-site, specificity, cost, simplicity, portability and reproducibility. The presented method can be used in disadvantaged areas of the world and blood transfusion centers. To the best of our knowledge, this is the first report of using PGMs for HBSAg detection. © 2018 Elsevier B.V.
Publication Date: 2011
Electrochimica Acta (00134686)56(9)pp. 3387-3394
A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with single wall carbon nanotubes (SWCNTs) and phenazine derivative of Mn-complex. With immersing the GC/CNTs modified electrode into Mn-complex solution for a short period of time 20-100 s, a stable thin layer of the complex was immobilized onto electrode surface. Modified electrode showed a well defined redox couples at wide pH range (1-12). The surface coverages and heterogeneous electron transfer rate constants (ks) of immobilized Mn-complex were approximately 1.58 × 10-10 mole cm-2 and 48.84 s-1. The modified electrode showed excellent electrocatalytic activity toward H2O2 reduction. Detection limit, sensitivity, linear concentration range and kcat for H 2O2 were, 0.2 μM and 692 nA μM-1 cm -2, 1 μM to 1.5 mM and 7.96(±0.2) × 103 M-1 s-1, respectively. Compared to other modified electrodes, this electrode has many advantageous such as remarkable catalytic activity, good reproducibility, simple preparation procedure and long term stability. © 2010 Elsevier Ltd. All rights reserved.
Publication Date: 2016
Journal of Materials Science (15734803)51(22)pp. 9991-10004
In this study, a novel PAN/NaX/ZnO nanocomposite absorbent was introduced and its ability to remove of uranium anionic species, which are the most dominant species of uranium in water at natural pH, from contaminated waters was studied. In this regards, micro and nano sized NaX zeolite and PAN/NaX/ZnO nanocomposite were successfully synthesized and characterized using various methods, including X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FT-IR), atomic absorption spectroscopy (AAS), and Brunauer–Emmett–Teller (BET) specific surface area analysis. Batch technique was used to study the adsorption behavior of uranium ions from contaminated water as a function of solid–liquid ratio, initial uranium concentration, contact time, and temperature. Results showed that although NaX nanozeolite due to its negative framework charge, showed low sorption capacity for adsorption of uranium anionic species but the composite of it with ZnO nanoparticles and polyacrylonitrile (PAN) effectively improved its uranium adsorption capacity. The novel PAN/NaX/ZnO nanocomposite could selectively remove uranium ions from contaminated water with removal efficiency of more than 98.65 % in the presence of all anions and cations which are available in waters. © 2016, Springer Science+Business Media New York.
Publication Date: 2021
Materials Chemistry and Physics (02540584)258
This study aimed to obtain high-density green pieces from α-alumina/amorphous alumina core-shell nanocomposite powder. This nanocomposite was initially obtained in the form of a pellet with high-green density using the slip-casting process. Then, it was sintered by a pressureless sintering method under vacuum conditions. The effects of slurry parameters, such as dispersant content, solid loading, and agglomeration for viscosity and green density, are investigated for optimizing the slip-casting conditions. The green sample with a density of 63% was obtained by using α-alumina/amorphous alumina core-shell nanocomposite powder after 13 h of wet milling and casting at 70% solid loading, 5 wt% Dolapix, and pH = 10.5. The sintered sample showed a relative density of 99.5% and a transmission of 72% in the IR region at 1300 °C under a vacuum condition. The application of the amorphous phase in the initial powder, as a shell, led to the sintering-aid of this phase and decreased sintering temperature. The slip-casting method also resulted in high-green density and consequently high-final density using pressureless sintering. © 2020 Elsevier B.V.
Publication Date: 2013
Ferroelectrics (15635112)448(1)pp. 123-133
Pb-partitioning phenomenon was investigated in PbTiO3 nanopowders produced via sol-gel processing in order to achieve highly crystalline and single phase tetragonal perovskite PbTiO3 nanoparticles. The calcination conditions were selected based on the simultaneous thermal analysis of the PbTiO3 gels, including complete burn out of the contained carbon and crystallization of the desired perovskite structure. X-Ray diffraction investigations confirmed key contributions of Pb stoichiometry and the gel calcination conditions to aid in improving formation of single tetragonal phase as well as avoiding formation of toxic lead compounds. Transmission electron microscopy investigations showed that well crystallized PbTiO3 nanoparticles have been synthesized after calcination of the PbTiO3 gel. © 2013 Copyright Taylor and Francis Group, LLC.
Publication Date: 2010
Analytical Sciences (09106340)26(8)pp. 897-902
A quantitative structure activity relationship (QSAR) study of 8-azaadenine, as antagonists for the A1 receptor, is described. A genetic algorithm (GA) method was used as the feature selection tool, and an adaptive neuro-fuzzy inference system (ANFIS) was employed for feature mapping. The best descriptors (GATS4v and BELv7) were applied to train the ANFIS model. The optimum number and shape of related functions were obtained through a subtractive clustering algorithm. The ability and robustness of the GA-ANFIS model in predicting the affinity of 8-azaadenine derivatives (pKi) are illustrated by validation techniques of Leave One Out, heuristic and randomized methods. The results have indicated that the proposed model of ANFIS in this work is superior over two other methods, radial basis function (RBF) and multiple linear regression (MLR). 2010 © The Japan Society for Analytical Chemistry.
Publication Date: 2012
Journal of Chemometrics (1099128X)26(5)pp. 135-142
A quantitative structure-activity relationship study of thyroid hormone receptors β1 is described in this paper. We used adaptive neuro-fuzzy inference system (ANFIS) and radial basis function (RBF) methods coupling to genetic algorithm (GA) to predict binding affinity of some ligands with β1 thyroid receptors. A set of 83 selective ligands with known affinity of thyroid receptors β1 (pIC50) were selected, and a large number of molecular descriptors were calculated for each molecule by Dragon. Seven most relevant descriptors were selected by GA-stepwise partial least squares as variable selection tool. The best descriptors (SCBO and EEig08x) and (SCBO, EEig08x, and BEHe1) were applied to train the ANFIS and RBF models, respectively. Then the number and shape of related functions were optimized. The ability and robustness of the GA-ANFIS, GA-RBF, and GA-multiple linear regression (MLR) models in predicting the pIC50 of thyroid receptors β1 are illustrated by internal validation technique of leave one out and also heuristic and randomized techniques as external validation methods. The results have indicated that the proposed models of ANFIS and RBF in this work are superior to MLR method because of generation of simpler models with only two and three descriptors, respectively. © 2012 John Wiley & Sons, Ltd.
Publication Date: 2021
RSC Advances (20462069)11(14)pp. 7862-7872
Curcumin is a polyphenolic compound with anti-oxidative and anti-cancer properties that is obtained from turmeric plants. Several studies have demonstrated that cancer cells are not killed unless they are exposed to 5-50 mM of curcumin. Consequently, it is vital to control the concentration of curcumin in cancer therapy. In this study, a sensitive electrochemical sensor was fabricated based on a beta-cyclodextrin-reduced graphene oxide (β-CD-rGO) nanocomposite for measuring curcumin concentration. The effects of experimental factors were investigated and the optimum parametric conditions were determined using the Taguchi optimization method. The β-CD-rGO modified electrode exhibited good electrochemical properties for curcumin detection. The results of differential pulse voltammetry experiments unveiled that the sensor shows a linear response to curcumin concentration over the range of 0.05-10 mM with a detection limit of 33 nM and sensitivity of 4.813 μA μM−1. The fabricated sensor exhibited selectivity in the presence of other electroactive species,e.g., propranolol, clomipramine and clonazepam. © The Royal Society of Chemistry 2021.
Publication Date: 2002
Separation and Purification Technology (1383-5866)26(2-3)pp. 221-226
A bulk liquid membrane consisted of 1.8 × 10-4 M Janus Green in chloroform that placed between an aqueous source phase containing 0.5 M sodium thiocyanate at pH 7 and an aqueous receiving phase with 0.1 5 M histidine at pH 7 results in an uphill transport of copper from the source phase to the receiving phase. The amount of copper transport through the liquid membrane after 180 min was 97.0 ± 1.7%. The presence of other metals such as Cd2+, Zn2+, Hg2+, Mg2+, Ag1+, Ni2+, Pb2+, Fe3+, K1+, Co2+ doesn't change the efficiency of copper transport. © 2002 Published by Elsevier Science B.V.
