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121.
Reza Mahmoudi Saeed Aghaei Zeinab Salehpour Ali Mousavizadeh Seyed Sajjad Khoramrooz Marzie Taheripour Sisakht Gunna Christiansen Marzieh Baneshi Bahman Karimi Hassan Bardania 《应用有机金属化学》2020,34(2):e5394
Due to environmentally friendly and cost- effective issues, biological methods for silver nanoparticles (AgNPs) synthesis are advantageous over chemical and physical ones. In this study, AgNPs synthesized using Lavandula stoechas extract as a reductant and its antioxidant capacity, antibacterial property and cytotoxicity effect were investigated. The phyto-synthesized AgNPs were characterized using various analyses such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) as well as Fourier transform infrared (FT-IR). The prepared nanoparticles were spherical on shape with the size about 20–50 nm. Antibacterial studies through agar disk diffusion method confirmed the antibacterial potential of phyto-synthesized AgNPs toward two clinical Staphylococus aureus and Pseudomonas aeruginosa bacteria, although MTT assay demonstrated that S. aureus (MIC = 125 μg/ml) was more susceptible to AgNPs than P. aeruginosa (MIC = 250 μg/ml). Moreover, the cytotoxicity assay of phyto-synthezied AgNPs showed a low cytotoxic effect on RAW264 cell line at 62.5 μg/ml as an effective concentration. Also the considerable antioxidant capacity of the AgNPs confirmed through DPPH assay. Great antibacterial and antioxidant properties along with biocompatibility make the suggested phyto-synthesized AgNPs a great candidate for different biomedical applications including wound healing. 相似文献
122.
Rezaei Shokoofe Rahpeima Soraya Esmaili Javad Javanbakht Vahid 《Russian Journal of Applied Chemistry》2021,94(4):533-548
Russian Journal of Applied Chemistry - Magnetic nanoparticles and clay minerals combine to form a class of advanced nanocomposites that would possess exceptional adsorption, magnetism, and... 相似文献
123.
Mohammad Tavakkoli Yaraki Soroosh Daqiqeh Rezaei Eshu Middha Yen Nee Tan 《Particle & Particle Systems Characterization》2020,37(5):2000027
In this study, a simple method to synthesize right silver bipyramid (AgBP) nanostructures via the seed-mediated growth cum oxidative etching approach in aqueous solution is developed. The key strategy of this method is to control the growth and etching process by careful adjustment of the reactants concentration. Ascorbic acid (AA) is used to reduce silver precursor while cetyltrimethylammonium bromide stabilizer is used to direct the preferential growth of (100) facets. The presence of Cu2+ and AA in the reaction mixture also enable in-situ generation of H2O2, leading to selective etching of (111) facets, which is crucial to the formation of anisotropic AgBPs. The structure-properties of AgBPs is systematically investigated through a series of experiments and theoretical simulations. Transmission electron microscope images and X-ray diffraction patterns of the as-synthesized AgBPs show the formation of single crystalline twined nanostructures with a relatively high yield. These results suggest the important role of the excitation of electric dipole in enhancing the electric field at the six sharp corners of AgBPs, making them especially promising for a wide range of technological applications including surface-enhanced Raman scattering with a significant enhancement factor of 1.50 × 105 as demonstrated herein. 相似文献
124.
A new catalytic spectrophotometric method is reported for the simultaneous determination of nitrite and nitrate by flow injection analysis, based on the catalytic effect of nitrite on the redox reaction between pyrogallolsulfonephthalein and potassium bromate in acidic media. Nitrate can also be on-line reduced to nitrite with a modified copper-coated cadmium reduction column. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of pyrogallolsulfonephthalein at 465 nm. Various analytical parameters such as effects of acidity, reagent concentrations, flow rates, sample sizes, lengths of the reaction coil and temperatures were studied and were optimized. Under the optimized conditions, the calibration graph was linear for 2.4 to 160 ng ml(-1) of nitrite and 4.0 to 100 ng ml(-1) of nitrate. The influences of potential interfering cations and anions for nitrite and nitrate determination were studied. The method is successfully applied for food and water samples. Up to ten samples can be analyzed per hour. 相似文献
125.
Arash Ghorbani-Choghamarani Zahra Heidarnezhad Bahman Tahmasbi Gouhar Azadi 《Journal of the Iranian Chemical Society》2018,15(10):2281-2293
In this work, Boehmite nanoparticles (BNPs) were synthesized in water using commercially available materials and further N,N,N′,N′-tetraethyldiethylentriamin (TEDETA) was supported on the surface of BNPs, and used as organo-basic catalyst in four-component Hantzsch reaction that provides access to pharmaceutically polyhydroquinoline derivatives and Knoevenagel reaction to afford α,β-unsaturated compounds. All products were obtained in excellent yields (89–98%) and good reaction times under green condition such as water and ethanol solvents. This catalyst was characterized using FT-IR, SEM, EDS, and TGA techniques. This catalyst was reused for several times without the significant loss of their catalytic efficiency. In addition, stability of catalyst after recycling was confirmed by TGA, SEM, EDS and FT-IR techniques. 相似文献
126.
Behzad Rezaei Maryam Mokhtarianpour Ali Asghar Ensafi 《Journal of the Iranian Chemical Society》2018,15(4):955-965
In this work, a 304 stainless steel (SS) was anodized to prepare nanoporous SS (NPSS) with an average size of about 75 nm and then filled with copper (Cu/NPSS) using pulsed electrodeposition method. Afterward, a nanostructural Pt and Pd film was deposited by galvanic replacement (GR) on the Cu/NPSS to prepare modified electrode (PtPd/Cu/NPSS) for hydrogen evolution reaction (HER) and formic acid electrooxidation (FAO). The electrocatalytic activity of the modified electrode and its structural characterization have been studied by voltammetric methods, electrochemical impedance spectroscopy (EIS), inductively coupled plasma optical emission spectrometry (ICP-OES), and field emission scanning electron microscopy (FESEM). The results show that the nanostructural Pt1Pd1/Cu/NPSS composition, with low Pt loading and suitable stability, has a good electrocatalytic performance toward HER (EOnset = + 12 mV vs. NHE) and FAO (EOnset = ?180 mV vs. NHE). For HER observed a high mass activity of noble metals (87.54 mA cm?2μg Pd+Pt ?1 ) in comparison with Pt deposited Cu/NPSS (41.5 mA cm?2 μg Pt ?1 ) at the same applied potential of ? 0.25 V versus NHE. Also, the fabricated electrocatalysts with more electrochemically active surface area in comparison with Pd/Cu/NPSS and Pt/Cu/NPSS revealed more resisting to the poisoning components and good stability for FAO. 相似文献
127.
The investigation of
norm Bernstein inequalities
for polynomials with unimodular coefficients, leads to unexpected results. Some phenomena here upset our intuition. This
paper closely revisits the ultraflat polynomials whose existence was conjectured by Littlewood in 1966 and proved by Kahane
in 1980. A major role in this study is also played by arbitrary ultraflat polynomials, that is, including those that are
not necessarily obtained by variations or refinements of Kahane's method. 相似文献
128.
One of the main electrochemical characteristics of a lead-acid battery is amount of water consumption. The effect of solidification temperature on electrochemical behavior (mainly hydrogen overvoltage) of Pb–Ca–Sn–Al (0.09%, Ca; 0.9%, Sn; 0.02%, Al) and Pb–Sb–Sn (1.7%, Sb; 0.24%, Sn) alloys, which are used in making the grid of lead-acid batteries, has been studied by cyclic voltammetry (CV) and linear sweep voltammety for different concentrations of sulfuric acid (ranging from 0.5 mol L–1 to 4.0 mol L–1). The morphology of the grid at some solidification temperatures was studied by optical microscopy. After one sweep of CV the surface of the electrode was investigated by using scanning electron microscopy.The results show that the potential of hydrogen evolution depends on the solidification temperature of the grids during production (mold temperature of grid casting). Also, at different solidification temperatures, different passivation phenomena, electrode surface constituents, and structure were observed. 相似文献
129.
130.
G. Rezaei Behbehani A. A. Saboury A. Fallah Baghery 《Journal of solution chemistry》2007,36(10):1311-1320
The interaction of myelin basic protein (MBP) from the bovine central nervous system with divalent calcium ion was studied
by isothermal titration calorimetry at 27 °C in aqueous solution. The extended solvation model was used to reproduce the enthalpies
of Ca2+-MBP interaction over the whole range of Ca2+ concentrations. The solvation parameters recovered from the solvation model were attributed to the structural change of MBP
due to the metal ion interaction. It was found that there is a set of two identical and non-interacting binding sites for
Ca2+ ions. The association equilibrium constant is 0.021 μmol⋅dm−3. The molar enthalpy of binding is ΔH=−15.10 kJ⋅mol−1. 相似文献