Search for: hydrazine
0.007 seconds
Total 24 records

    Accelerated differentiation of neural stem cells into neurons on ginseng-reduced graphene oxide sheets

    , Article Carbon ; Volume 66 , January , 2014 , Pages 395-406 Akhavan, O ; Ghaderi, E ; Abouei, E ; Hatamie, S ; Ghasemi, E ; Sharif University of Technology
    Asian red ginseng was used for green reduction of chemically exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). The reduction level and electrical conductivity of the ginseng-rGO sheets were comparable to those of hydrazine-rGO ones. Reduction by ginseng resulted in repairing the sp 2 graphitic structure of the rGO, while hydrazine-rGO showed more defects and/or smaller aromatic domains. The ginseng-rGO sheets presented a better stability against aggregation than the hydrazine-rGO ones in an aqueous suspension. Whilst the hydrophobic hydrazine-rGO films exhibited no toxicity against human neural stem cells (hNSCs), the hydrophilic GO and ginseng-rGO films (as more... 

    Effect of hydrazine hydrate on the luminescence properties of MPA capped CdTe nanocrystals in hot injection method

    , Article Journal of Luminescence ; Vol. 156, issue , 2014 , p. 235-239 Mobedi, N ; Marandi, M ; Zare Bidaki, H ; Sharif University of Technology
    In this research MPA capped CdTe nanocrystals with sizes around 2.7-3.5 nm were grown in aqueous solution. The process was performed through the reaction of NaHTe with MPA and CdCl2 solution in high temperature. The synthesis was carried out in two different states of standard and modified forms. In the modified synthesis, the hydrazine hydrate material was added to the MPA plus CdCl2 solution before injection. The evolution of the nanocrystals size and PL quantum yield was monitored during the heating time for the growth. The results demonstrated that for the standard synthesis the growth rate was slow. The CdTe nanocrystals with high PL quantum yields were achieved in more than 10 h of... 

    Optical detection of some hydrazine compounds based on the surface plasmon resonance band of silver nanoparticles

    , Article Spectroscopy Letters ; Volume 46, Issue 1 , 2013 , Pages 73-80 ; 00387010 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Fotovat, M ; Sharif University of Technology
    An indirect colorimetric method is presented for spectrophotometric determination of hydrazine, phenylhydrazine, and isoniazid. Reduction of silver ions to silver nanoparticles (AgNPs) by these analytes as active reducing agents in the presence of polyvinylpyrrolidone (PVP) and also cetyltrimethylammonium chloride (CTAC) as a stabilizer is the basis of the proposed method. The changes in plasmon absorbance of the AgNPs at λ = 415 nm in the presence of PVP were proportional to concentration of hydrazine, phenylhydrazine, and isoniazid in the ranges of 4.0-150.0 μM, 1.0-55.0 μM, and 2.0-30.0 μM, respectively, and the detection limit obtained was 0.79 μM. In the presence of CTAC, the linear... 

    Size-dependent genotoxicity of graphene nanoplatelets in human stem cells

    , Article Biomaterials ; Volume 33, Issue 32 , 2012 , Pages 8017-8025 ; 01429612 (ISSN) Akhavan, O ; Ghaderi, E ; Akhavan, A ; Sharif University of Technology
    Reduced graphene oxide nanoplatelets (rGONPs) were synthesized by sonication of covalently PEGylated GO sheets followed by a chemical reduction using hydrazine and bovine serum albumin. Human mesenchymal stem cells (hMSCs), as a fundamental factor in tissue engineering, were isolated from umbilical cord blood (as a recently proposed source for extracting fresh hMSCs) to investigate, for the first time, the size-dependent cyto- and geno-toxic effects of the rGONPs on the cells. The cell viability test showed significant cell destructions by 1.0 μg/mL rGONPs with average lateral dimensions (ALDs) of 11±4 nm, while the rGO sheets with ALDs of 3.8±0.4 μm could exhibit a significant cytotoxic... 

    Increasing the antioxidant activity of green tea polyphenols in the presence of iron for the reduction of graphene oxide

    , Article Carbon ; Volume 50, Issue 8 , 2012 , Pages 3015-3025 ; 00086223 (ISSN) Akhavan, O ; Kalaee, M ; Alavi, Z. S ; Ghiasi, S. M. A ; Esfandiar, A ; Sharif University of Technology
    An easy method for green and low-temperature (40 °C) reduction of graphene oxide (GO) by increasing the antioxidant activity of green tea polyphenols (GTPs) in the presence of iron was developed. The reduction level (obtained by X-ray photoelectron spectroscopy) and electrical conductivity (obtained by current-voltage measurement) of the GO sheets reduced by GTPs in the presence of iron were comparable to those of hydrazine-reduced GO and much better than those of the GO reduced by only GTPs (in the absence of iron) at reduction temperatures of 40-80 °C. Raman spectroscopy indicated that application of GTPs in the presence of iron, in contrast to hydrazine, resulted in better recovering of... 

    Melatonin as a powerful bio-antioxidant for reduction of graphene oxide

    , Article Journal of Materials Chemistry ; Volume 21, Issue 29 , 2011 , Pages 10907-10914 ; 09599428 (ISSN) Esfandiar, A ; Akhavan, O ; Irajizad, A ; Sharif University of Technology
    Graphene is usually synthesized through deoxygenation of graphene oxide (GO) by hydrazine as the most common and one of the strongest reducing agents. But, due to the high toxicity of hydrazine, it is not a promising reductant in large-scale production of graphene. Here, for the first time, we used melatonin (MLT), as a powerful antioxidant and a biocompatible competitor of hydrazine in reduction of GO suspension. X-ray photoelectron spectroscopy (XPS), current-voltage and optical characteristics of the sheets indicated that the deoxygenation efficiency of the GO suspensions by MLT and under heating in an alkaline condition for 3 h was comparable with the efficiency obtained by hydrazine in... 

    Determination of Hydrazine and Phenylhydrazine Based on Formation of Gold Nanoparticles Stabilized with Non-ionic Surfactants

    , M.Sc. Thesis Sharif University of Technology Karami, Pari (Author) ; Hormozi Nezhad, Mohammad Reza (Supervisor)
    A simple and effective procedure is proposed for colorimetric detection of hydrazine and phenylhydrazine. It was found that the reduction of AuCl4- to gold nanoparticles (Au-NPs) by these compunds in the presence of Tween-20 as a stabilizing agent produced very intense surface plasmon resonance peak of Au-NPs. The plasmon absorbance of the Au-NPs allows the quantitative spectrophotometric detection of the hydrazine and phenylhydrazine. The calibration curves derived from the changes in absorbance at λ = 530 and λ = 550 nm for hydrazine and phenylhydrazine, respectively were linear with concentration of hydrazine and phenylhydrazine in the range of 1.0×10-6- 2.0×10-4 M, 5×10-6 - 4×10-4 M,... 

    Bacteriorhodopsin as a superior substitute for hydrazine in chemical reduction of single-layer graphene oxide sheets

    , Article Carbon ; Volume 81, Issue 1 , 2015 , Pages 158-166 ; 00086223 (ISSN) Akhavan, O ; Sharif University of Technology
    Elsevier Ltd  2015
    Bacteriorhodopsin (bR) molecules were utilized as light-driven proton pumps for green as well as effective reduction of single-layer graphene oxide (GO) sheets. The bR molecules and graphene sheets were separated from each other in an aqueous environment by using a polytetrafluoroethylene membrane filter, in order to prevent their direct interactions (including attachment of the bR molecules onto the GO). Although reduction of GO using hydrazine or bR showed similar deoxygenation levels (based on X-ray photoelectron spectroscopy), the former resulted in formation of CAN bonds which can substantially decrease the electrical conductivity of the reduced sheets. The electrical characteristics of... 

    Hydrogen-rich water for green reduction of graphene oxide suspensions

    , Article International Journal of Hydrogen Energy ; Volume 40, Issue 16 , 2015 , Pages 5553-5560 ; 03603199 (ISSN) Akhavan, O ; Azimirad, R ; Gholizadeh, H. T ; Ghorbani, F ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract H2-rich water as a green antioxidant was applied for deoxygenation of graphene oxide (GO) suspensions. The ability of H2-rich water for deoxygenation of GO sheets was found comparable to the ability of hydrazine (as a standard and powerful reductant), using X-ray photoelectron spectroscopy. In fact, the O/C ratio of GO sheets could be reduced from 0.51 to 0.21 and 0.16 by H2-rich water and hydrazine, respectively. More importantly, while C-N bond formation is one of the side effects of GO reduction by hydrazine, no chemical C-N bond was found on the H2-water-reduced GO (rGO) sheets. This also resulted in a better restoration of the graphitic structure of the H2-water-rGO, as... 

    Graphene nanomesh by ZnO nanorod photocatalysts

    , Article ACS Nano ; Volume 4, Issue 7 , 2010 , Pages 4174-4180 ; 19360851 (ISSN) Akhavan, O ; Sharif University of Technology
    Local photodegradation of graphene oxide sheets at the tip of ZnO nanorods was used to achieve semiconducting graphene nanomeshes. The chemically exfoliated graphene oxide sheets, with a thickness of ∼0.9 nm, were deposited on quartz substrates. Vertically aligned ZnO nanorod arrays with diameters of 140 nm and lengths of <1 μm were grown on a glass substrate by using a hydrothermal method. The graphene oxide sheets were physically attached to the tip of the ZnO nanorods by assembling the sheets on the nanorods. UV-assisted photodegradation of the graphene oxide sheets (with dimension of ∼5 × 5 μm) at a contact place with the ZnO nanorods resulted in graphene nanomeshes with a pore size of... 

    Simultaneous voltammetric determination of ascorbic acid, acetaminophen and isoniazid using thionine immobilized multi-walled carbon nanotube modified carbon paste electrode

    , Article Electrochimica Acta ; Volume 55, Issue 3 , 2010 , Pages 666-672 ; 00134686 (ISSN) Shahrokhian, S ; Asadian, E ; Sharif University of Technology
    A carbon paste electrode (CPE) modified with thionine immobilized on multi-walled carbon nanotube (MWCNT), was prepared for simultaneous determination of ascorbic acid (AA) and acetaminophen (AC) in the presence of isoniazid (INZ). The electrochemical response characteristics of the modified electrode toward AA, AC and INZ were investigated by cyclic and differential pulse voltammetry (CV and DPV). The results showed an efficient catalytic role for the electro-oxidation of AA and AC, leading to a remarkable peak resolution (∼303 mV) for two compounds. On the other hand, the presence of INZ, which is considered as important drug interference for AC, does not affect the voltammetric responses... 

    A low cost and highly active non-noble alloy electrocatalyst for hydrazine oxidation based on nickel ternary alloy at the surface of graphite electrode

    , Article Journal of Electroanalytical Chemistry ; Volume 763 , 2016 , Pages 134-140 ; 15726657 (ISSN) Jafarian, M ; Rostami, T ; Mahjani, M. G ; Gobal, F ; Sharif University of Technology
    Elsevier B.V  2016
    The electrocatalytic oxidation of hydrazine was studied over Ni, Cu, Co and Ni-based ternary alloy on graphite electrodes in alkaline solution. The catalysts were prepared by cycling the graphite electrode in solutions containing Ni, Cu and Co ions at cathodic potentials. The synergistic effects and the catalytic activity of the modified electrodes were investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). It was found that, in the presence of hydrazine, the modified Ni-based ternary alloy electrode (G/NiCuCo) exhibited a good catalytic activity for the oxidation of hydrazine at a reduced overpotential and it has a significant high... 

    Hydrazine-modified starch coated magnetic nanoparticles as an effective pH-responsive nanocarrier for doxorubicin delivery

    , Article Journal of Industrial and Engineering Chemistry ; Volume 39 , 2016 , Pages 203-209 ; 1226086X (ISSN) Zohreh, N ; Hosseini, S. H ; Pourjavadi, A ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2016
    A novel, magnetic nanocarrier was successfully synthesized through a facile and economical producer in which Fe3O4 magnetic nanoparticles were coated by starch-g-poly (methyl methacrylate-co-PEG-acrylamide). The surface of nanocarrier was then modified by hydrazine to preparation of a pH-responsive carrier. The resulted nanocarrier was applied for delivery of doxorubicin (DOX) as an effective anti-cancer drug. DOX was reacted with hydrazine linkage on the surface of nanocarrier to form hydrazone bond. Due to the presence of numerous hydrazine groups on the surface of magnetic nanocarrier large amounts of DOX was loaded onto the carrier (327 mg g−1). © 2016 The Korean Society of Industrial... 

    Low-temperature solution-based processing to 7.24% efficient superstrate CuInS2 solar cells

    , Article Solar Energy ; Volume 157 , 2017 , Pages 581-586 ; 0038092X (ISSN) Cheshme Khavar, A.H ; Mahjoub, A. R ; Taghavinia, N ; Sharif University of Technology
    Elsevier Ltd  2017
    The fabrication of high performance, solution-processed CIGS family solar cells is based on high-temperature crystallization processes in chalcogen-containing atmosphere and/or using dangerous solvents like hydrazine. The non-hydrazine sulfurization- and selenization-free reports typically suffer from poor grain structures. We report a facile strategy to overcome grain growth limitations at very low temperature processing (250 °C). Selenium free Superstrate configuration CuInS2 (CIS) solar cells are fabricated using a nanocrystals ink which avoiding from high temperature selenization or/and sulfurization is targeted. We investigated the effect of intentional M doping (M = Sb, Zn, Cd and Sn)... 

    Analysis and Conceptual Design of Incinerator for Damaging Hydrazine Matters

    , M.Sc. Thesis Sharif University of Technology Golsefatan, Mohammad (Author) ; Darbandi, Masoud (Supervisor)
    Hydrazine is considered as one of the most dangerouswaste materials from the environmental point of view. It can lead to both air and soil pollutions. Unfortunately,Hydrazine fuel is largly used in aerospace industry. Therefor, the aerospace industries are indirectly engaged with such pollutions.As a remedy incineration can be considered a very effective solution to destroy hydrazine fuel. In this thesis, we are faced with the conceptual design of an incinerator, which is going to be used for hydrazine incinerations.In this regard we are expected to consider all restrictions,which are required to be considered in a reed incinerator design and application. Therefore, we need to determine... 

    Synthesis and characterization of magnetic hybrid nanomaterials via RAFT polymerization: A pH sensitive drug delivery system

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 174 , 2019 , Pages 153-160 ; 09277765 (ISSN) Pourjavadi, A ; Kohestanian, M ; Shirzad, M ; Sharif University of Technology
    Elsevier B.V  2019
    Herein, a facile and versatile method for the synthesis of a novel magnetic nanocarrier via surface- initiated reversible addition-fragmentation chain transfer (RAFT) polymerization is introduced. At first, RAFT agent was successfully attached to the surface of Fe 3 O 4 nanoparticles and, then, poly (glycidyl methacrylate) (PGMA) chains were grown and anchored onto the surface of Fe 3 O 4 nanoparticles. At the end, hydrazine (Hy) groups were introduced to the PGMA chains via reaction between epoxy rings and hydrazine molecules. Doxorubicin (DOX) was covalently conjugated to the prepared nanocarrier (Fe 3 O 4 @PGMA@Hy) through a hydrazone linkage. The in vitro drug release of Fe 3 O 4... 

    Preparation of Nanocomposites Consisting of Nickel Oxide Nanostructures Grown on Hollow Carbon Nanospheres and Evaluation of their Ability for Electrooxidation of Hydrazine Hydrate

    , M.Sc. Thesis Sharif University of Technology Taghaddosi, Sanaz (Author) ; Shahrokhian Dehkordi, Saeed (Supervisor)
    In the present work, nanocomposites consisting of nickel oxide nanostructures and a hollow carbon substrate were used to modify a glassy carbon electrode's surface for the electrooxidation of hydrazine hydrate. For this purpose, hollow carbon nanospheres were first synthesized using aniline and pyrrole copolymerization process without any template needing. The hollow carbon nanospheres prepared by this method have outstanding features such as high specific surface area and good stability. On the other hand, they did not require toxic and environmentally harmful solvents to remove the template. In this study, after preparing hollow carbon nanospheres as a suitable substrate, different... 

    Graphene oxide nanoplatforms reduction by green plant-sourced organic compounds for construction of an active anti-corrosion coating; experimental/electronic-scale DFT-D modeling studies

    , Article Chemical Engineering Journal ; Volume 397 , 1 October , 2020 Mohammadkhani, R ; Ramezanzadeh, M ; Akbarzadeh, S ; Bahlakeh, G ; Ramezanzadeh, B ; Sharif University of Technology
    Elsevier B.V  2020
    In this study, the Peganum harmala seed extract (PHSE) was used as a green reducing agent of graphene oxide with high deoxygenation capability. PHSE not only acts as a reducing agent of GO due to the high amount of nitrogen-rich compounds but also plays an essential role in the particles' active anti-corrosion performance improvement. In order to add more active inhibition property, the zinc cations were doped successfully on the chemical structure of GO nanosheets, and eventually, the RGO-PHSE-Zn nanocomposite was obtained. The FT-IR results and UV–visible achievements declared that the epoxide (-C-O-C-) functional groups attached to the surface of the GO nanosheets had been successfully... 

    Graphene oxide functionalized with oxygen-rich polymers as a pH-sensitive carrier for co-delivery of hydrophobic and hydrophilic drugs

    , Article Journal of Drug Delivery Science and Technology ; Volume 56 , 2020 Pourjavadi, A ; Asgari, S ; Hosseini, S. H ; Sharif University of Technology
    Editions de Sante  2020
    In this work, a novel carrier based-on modified graphene oxide was designed for co-delivery of hydrophobic and hydrophilic anticancer drugs (curcumin (Cur) and doxorubicin (DOX) as the model of drugs). The hydroxyl groups at the edges of graphene oxide (GO) sheets were used as the initiation sites for growing poly(epichlorohydrin) (PCH) chains. Then, hyperbranched polyglycerol (HPG) was grafted on the hydroxyl end groups of PCH (PCH-g-HPG). Pendant chlorines in the main chain of GO-PCH-g-HPG were replaced with hydrazine. The modification of GO sheets with oxygen-rich polymers increased water solubility of graphene oxide. Doxorubicin was loaded onto the nanocarrier by covalent bonding with... 

    Facile synthesis of N-doped hollow carbon nanospheres wrapped with transition metal oxides nanostructures as non-precious catalysts for the electro-oxidation of hydrazine

    , Article Journal of Electroanalytical Chemistry ; Volume 873 , 2020 Taghaddosi, S ; Rezaee, S ; Shahrokhian, S ; Sharif University of Technology
    Elsevier B.V  2020
    In the present work, N-doped hollow carbon nanospheres (N-HCNSs) is prepared by direct carbonization of polyaniline-co-polypyrrole (PACP) hollow spheres without template needing. Two different NiO nanostructures (nanosheets and nanowires) are prepared by forming a shell around the N-HCNSs via simple hydrothermal/calcination processes (NiO-NSs@N-HCNSs and NiO-NWs@N-HCNSs). The morphology and structure of the nanostructures are characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The prepared nanocomposites are used as catalysts for the electrocatalytic...