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    Hydrothermal synthesis of ZnO nanorod arrays for photocatalytic inactivation of bacteria

    , Article Journal of Physics D: Applied Physics ; Volume 42, Issue 22 , 2009 ; 00223727 (ISSN) Akhavan, O ; Mehrabian, M ; Mirabbaszadeh, K ; Azimirad, R ; Sharif University of Technology
    Arrays of ZnO nanorods were synthesized on ZnO seed layer/glass substrates by a hydrothermal method at a low temperature of 70 °C. The effect of pH > 7 of the hydrated zinc nitrate-NaOH precursor on the morphology and topography (e.g. size, surface area and roughness), the optical characteristics (e.g. optical transmission and band-gap energy), hydrophilicity and antibacterial activity of the grown ZnO nanostructure and nanorod coatings were investigated. For pH = 11.33 of the precursor (NaOH concentration of 0.10M), a fast growth of ZnO nanorods on the seed layer (length of ∼1 νm in 1.5 h) was observed. The fast growth of the ZnO nanorods resulted in a significant reduction in the optical... 

    A Practical Examination of the Antibacterial and Absorption Effect of Bioceramic Apatite-Coated TiO2 as a Modified Nanophotocatalyst

    , M.Sc. Thesis Sharif University of Technology Azimzadeh Irani, Maryam (Author) ; Gholami, Mohammad Reza (Supervisor) ; Haghighi, Saeed (Co-Advisor)
    Ag / AgCl /TiO2 , 2 Ap / Ag / AgCl /TiO , 2 AgI /TiO and 2 Ap / AgI /TiO were prepared by the deposition-precipitation method on 2TiO (P25) nanoparticles and their photocatalyctic activities have been investigated under visible light and dark environments. Cationic surfactant plus 2 PVPI (topical solution and dry powder) as an iodine ion source and nonionic surfactant plus KI as an iodide ion source were used to prepar 2 AgI /TiO . In less than 30 minutes, 2 AgI /TiO which has been resulted from combination of cationic surfactant and 2 PVPI showed high efficiency on Escherichia coli under visible light when small quantities of it is used . However, AgCl sample prepared with cationic... 

    Synthesis of Zeolite-Based NanoComposites and Investigation of their Catalytic Activities

    , M.Sc. Thesis Sharif University of Technology Padervand, Mohsen (Author) ; Gholami, Mohammad Reza (Supervisor)
    Polyagent photocatalysts based on the zeolite including TiO2, Ag and AgBr prepared by Sol-gel method. Ag and AgBr prevent of electron-hole recombination and enhance photocatalytic activity. Prepared catalysts were characterized by different analysis method including XRD, SEM, EDX, FTIR and BET techniques. Catalyst activities were investigated from two aspects: in first step the activities of catalyst were investigated for degradation of AB92 dye. The effect of different factors such as: catalyst concentration, dye concentration, pH and scavenger (sodium thiosulphate) on efficiency and reaction rate were investigated. The optimazed values for all conditions specified, then catalyst activities... 

    , M.Sc. Thesis Sharif University of Technology Aftabi, Abed (Author) ; Yaghmaei, Soheyla (Supervisor) ; Maghsoudi, Vida (Supervisor)
    This practice investigates about the resistance & sustainability of a sample of available microorganisms in fruit juices vs. a natural anti microbe called vanillin. To be more precisely the anti bacterial characteristic of vanillin has been tested against famous pathogenic organism Escherichia Coli in apple juice. The practice has been experienced for different concentrations of Vanillin, controlling & reducing the microbe concentration in apple synthetic juice. The effect has been investigated by measuring sensitivity of results in two different temperatures one in 8 degree of centigrade & other in 15, in each temperature two PH have been tested (PH = 3.5 & 4.5) 0-40-80 m-molar as 3... 

    Investigation of Effective Parameters on Performance of Microfluidic Microbial Fuel Cell–Microbial Electrolysis Cell Coupled System

    , M.Sc. Thesis Sharif University of Technology Fadakar, Aref (Author) ; Bastani, Dariush (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Mardanpour, Mohammad Mahdi (Co-Supervisor)
    This study presents the experimental investigation of the microfluidic microbial fuel cell – microbial electrolysis cell coupled system as a bioenergy generator to produce biohydrogen without any external power supply. The effect of microbial fuel cells number (to provide the required potential for microbial electrolysis cell), the type of substrate and its concentration were assessed. The maximum produced hydrogen of 25, 33 and 50 ppm were obtained in flow rate of 200 μl h-1 and glucose concentration of 200 mg l-1 in 1, 2 and 3 stack MFCs, respectively. For urea solution, by combination of 1, 2 and 3 stack MFCs in the flow rate of 200 μl h-1 and the concentration of 800 mg l-1, the maximum... 

    Photocatalytic property of Fe2O3 nanograin chains coated by TiO2 nanolayer in visible light irradiation

    , Article Applied Catalysis A: General ; Volume 369, Issue 1-2 , 2009 , Pages 77-82 ; 0926860X (ISSN) Akhavan, O ; Azimirad, R ; Sharif University of Technology
    The visible light photocatalytic activity of α-Fe2O3 nanograin chains coated by anatase TiO2 nanolayer, as a photocatalyst thin film for inactivation of Escherichia coli bacteria, was investigated for the solutions containing 106 colony forming units per milliliter of the bacteria, without and with H2O2 (60 μM). Thin films of the α-Fe2O3 nanograins with the grain size of 40-280 nm were grown on glass substrates by post-annealing of the thermal evaporated Fe3O4 thin films at 400 °C in air. The TiO2 layer with thickness of about 20 nm was coated on the nanograins by dipping the Fe2O3 thin films in a prepared TiO2 sol and re-annealing them at 400 °C in air. The antibacterial activity of the... 

    Synthesis of titania/carbon nanotube heterojunction arrays for photoinactivation of E. coli in visible light irradiation

    , Article Carbon ; Volume 47, Issue 14 , 2009 , Pages 3280-3287 ; 00086223 (ISSN) Akhavan, O ; Abdolahad, M ; Abdi, Y ; Mohajerzadeh, S ; Sharif University of Technology
    TiO2/multi-wall carbon nanotube (MWNT) heterojunction arrays were synthesized and immobilized on Si(0 0 1) substrate as photocatalysts for inactivation of Escherichia coli bacteria. The vertically aligned MWNT arrays were grown on ∼5 nm Ni thin film deposited on the Si by using plasma enhanced chemical vapor deposition at 650 °C. Then, the MWNTs were coated by TiO2 using dip-coating sol-gel method. Post annealing of the TiO2/MWNTs at 400 °C resulted in crystallization of the TiO2 coating and formation of Ti-C and Ti-O-C carbonaceous bonds at the heterojunction. The visible light-induced photoinactivation of the bacteria increased from MWNTs to TiO2 to TiO2/MWNTs, in which the bacteria could... 

    Bactericidal effects of Ag nanoparticles immobilized on surface of SiO2 thin film with high concentration

    , Article Current Applied Physics ; Volume 9, Issue 6 , 2009 , Pages 1381-1385 ; 15671739 (ISSN) Akhavan, O ; Ghaderi, E ; Sharif University of Technology
    Bactericidal activity of high concentration Ag nanoparticles immobilized on surface of an aqueous sol-gel silica thin film was investigated against Escherichia coli and Staphylococcus aureus bacteria. Size of the surface nanoparticles was estimated in the range of 35-80 nm by using atomic force microscopy. Due to accumulation of the silver nanoparticles at near the surface (at depth of 6 nm and about 40 times greater than the silver concentration in the sol), the synthesized Ag-SiO2 thin film (with area of 10 mm2) presented strong antibacterial activities against E. coli and S. aureus bacteria with relative rate of reduction of the viable bacteria of 1.05 and 0.73 h-1 for initial... 

    Storage of Ag nanoparticles in pore-arrays of SU-8 matrix for antibacterial applications

    , Article Journal of Physics D: Applied Physics ; Volume 42, Issue 13 , 2009 ; 00223727 (ISSN) Akhavan, O ; Abdolahad, M ; Asadi, R ; Sharif University of Technology
    Silver nanoparticles (NPs) stored in pore-arrays (pa) SU-8 photoresist layer were utilized as an antibacterial nanocomposition against E. coli bacteria. The pa-SU-8 matrix was fabricated by an optical interference lithography method resulting in small pores with a diameter of ∼50 nm and a depth of ∼100 nm. The Ag NPs were deposited on the soft polymeric matrix at different drying temperatures of 50 and 90 °C. X-ray photoelectron spectroscopy showed that the deposited silver NPs were substantially in the metallic state, independent from the drying condition. However, the concentration of the immobilized Ag NPs on the film surface increased (by a factor of 2.5) at the higher drying... 

    Investigation of the Performance of Microbial Fuel Cell Based on Shewanella Bacteria with the Aim of Nanostructured Materials

    , M.Sc. Thesis Sharif University of Technology Davoudi, Omid (Author) ; Yaghmaei, Soheila (Supervisor) ; Sanaee, Zeinab (Co-Supervisor)
    The development of clean, renewable and alternative sources of fossil fuels has increased in recent years due to various factors such as environmental pollution, reduced fossil fuel resources and increased energy consumption. The application of microbial fuel cells is one of the clean energy production methods using renewable sources such as municipal sewage. The microbial fuel cell converts the chemical energy stored in organic materials into electrical energy and simultaneously purifies the sewage. Increasing current density and power density are the most important challenges for microbial fuel cells. In this study, the two biocatalysts of Shewanella Oneidensis MR1 and Escherichia coli... 

    Lasting antibacterial activities of Ag-TiO2/Ag/a-TiO2 nanocomposite thin film photocatalysts under solar light irradiation

    , Article Journal of Colloid and Interface Science ; Volume 336, Issue 1 , 2009 , Pages 117-124 ; 00219797 (ISSN) Akhavan, O ; Sharif University of Technology
    Photodegradation of Escherichia coli bacteria in presence of Ag-TiO2/Ag/a-TiO2 nanocomposite film with an effective storage of silver nanoparticles was investigated in the visible and the solar light irradiations. The nanocomposite film was synthesized by sol-gel deposition of 30 nm Ag-TiO2 layer on ∼200 nm anatase(a-)TiO2 film previously doped by silver nanoparticles. Both Ag/a-TiO2 and Ag-TiO2/Ag/a-TiO2 films were transparent with a SPR absorption band at 412 nm. Depth profile X-ray photoelectron spectroscopy showed metallic silver nanoparticles with diameter of 30 nm and fcc crystalline structure were self-accumulated on the film surface at depth of 5 nm of the TiO2 layer and also at the... 

    Capping antibacterial Ag nanorods aligned on Ti interlayer by mesoporous TiO2 layer

    , Article Surface and Coatings Technology ; Volume 203, Issue 20-21 , 2009 , Pages 3123-3128 ; 02578972 (ISSN) Akhavan, O ; Ghaderi, E ; Sharif University of Technology
    In this work, aligned and compact Ag nanorods capped by sol-gel mesoporous TiO2 layer were grown on Ti/Si(100) in order to be applied in antibacterial applications. The Ag nanorods with a high effective surface were grown by applying an electric field perpendicular to the surface of the Ag/Ti/Si thin film while it was being heat-treated at 700 °C in an Ar + H2 ambient. The grown silver nanorods had widths and lengths of 20-50 and 250-500 nm with an abundance in {100} facet, respectively. The TiO2 cap layer also had the specific surface area, the total pore volume and the pore diameter of 474 m2/g, 0.49 cm3/g and 8.0 nm, respectively. Antibacterial activities of the TiO2-capped Ag nanorods... 

    Enhancement of antibacterial properties of Ag nanorods by electric field

    , Article Science and Technology of Advanced Materials ; Volume 10, Issue 1 , 2009 ; 14686996 (ISSN) Akhavan, O ; Ghaderi, E ; Sharif University of Technology
    The effect of an electric field on the antibacterial activity of columnar aligned silver nanorods was investigated. Silver nanorods with a polygonal cross section, a width of 20-60 nm and a length of 260-550 nm, were grown on a titanium interlayer by applying an electric field perpendicular to the surface of a Ag/Ti/Si(100) thin film during its heat treatment at 700 °C in an Ar+H2 environment. The optical absorption spectrum of the silver nanorods exhibited two peaks at wavelengths of 350 and 395 nm corresponding to the main surface plasmon resonance bands of the one-dimensional silver nanostructures. It was found that the silver nanorods with an fcc structure were bounded mainly by {100}... 

    Optimization for Production & Purification of Asparaginase Enzyme

    , M.Sc. Thesis Sharif University of Technology Dashtban Kenari, Laleh (Author) ; Alemzadeh, Iran (Supervisor) ; Maghsodi, Vida (Supervisor)
    The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile Acute Lymphocytic Leukemia [ALL] and Lymphosarcomas. The present study discusses the studies carried out for the optimal production of the enzyme from Escherichia coli ATCC 11303. For extraction of the intracellular enzyme, Sonication is more useful method for cell disruption than alkali lysis and enzymatic method. We improved Luria Bertani (LB) media (tryptone 1% w/v,... 

    Synthesis and Experimental Study of Organic-Metal Framework (MOF) Nanophotocatalists with Antibacterial Properties

    , M.Sc. Thesis Sharif University of Technology Rahmati, Ziba (Author) ; Vossoughi, Manouchehr (Supervisor) ; Abdi, Jafar (Co-Supervisor)
    MOFs are new class of materials that are used in different scientific fields because of their hybrid structure. In this project, focused on two specific applications, and aim is synthesis of a nanostructure which has antibacterial and photocatalytic activity. ZIF-8 because of its chemical and physical stability has been studied. For improving antibacterial influence and photocatalytic activity, silver nanoparticles are added to the structure. Magnetic nanoparticles covered by silica were used as core to facilitate separation process, ZIF-8 structure was constructed as shell on SiO2@Fe2O3 nano spheres. Magnetic nanoparticles improving stability of ZIF-8 in aqueous solutions. Synthetic nano... 

    Synthesis and Investigation of Antibacterial Activity of Nanostructures Carbon Nitride g-C3N4 Photocatalyst under Visible Light

    , M.Sc. Thesis Sharif University of Technology Ahmadi, Marzie (Author) ; RoustaAzad, Reza (Supervisor) ; Vosoughi, Manouchehr (Supervisor) ; Padervand, Mohsen (Supervisor)
    Carbon nitride is a compound that has the proper energy gap (2.7 eV) for activities in the visible light. In this research, photocatalysts based on nanoporous Carbon nitride sheets was synthesized with three primary ingredient (urea, melamine and melamine hydrochloride) by pyrolysis method. Ag, Cu, Fe2O3 and Fe3O4 were added to the system to prevent the electron-hole recombination as well as increscent the photocatalytic activity. The chemical bonding state properties and microstructure of the synthesized photocatalysts were investigated by means of XRD, SEM, BET, FTIR, DRS and PL methods. In the first step of the research, the activity of prepared compounds was analyzed by visible light for... 

    Antibacterial Activity of Magnetic Fe3O4/X (X=Ag, Cu, Au) Nanocomposites Modified with Ionic Liquid

    , M.Sc. Thesis Sharif University of Technology karimiasl, Moslem (Author) ; Gholami, Mohammad Reza (Supervisor)
    In this thesis, Fe3O4 magnetic nanoparticles were produced using co-precipitation method. The surface of these magnetic nanoparticles is modified by ionic-liquid groups, and then coated with Cu, Au and Ag metals. These nanoparticles were unstable before their surface modification, so that they were easily agglomerated. However, after their surface is modified with ionic-liquid, they become very stable and are easily solved in polar and non-polar solvents. This solubility depends on the alkyls groups connected to the ionic-liquid. Magnetic nano composites Fe3O4/X (X=Ag, Cu, Au) modified by ionic-liquid are prepared by absorbing Cu(NO3)2, HAuClO4 and AgNO3 salts on the surface of modified... 

    Synthesis of Fe3O4 Core-Shell Nanoparticles; Embedding Cu, Ag, Au Metals in the Surfaces that Were Modified by PPG and PEG Polymers and Investigation of Antibacterial Properties of These Composites

    , M.Sc. Thesis Sharif University of Technology Kiani Karanji, Ahmad (Author) ; Gholami, Mohammad Reza (Supervisor) ; Haghighi, Saeed (Co-Advisor)
    In this project, Fe3O4 magnetic nanoparticles were prepared by co-precipitation method. For protecting them against oxidation and also avoiding from direct contact between core and additional materials that probably makes unwanted reactions, the surface of nanoparticles were coated by SiO2 layer. Being easy to modify and having the control of interactions between nanoparticles are the advantages of coating nanoparticles with silica. The obtained Fe3O4@SiO2 core-shell nanoparticles were covered by two types of polymer (PPG and PEG). The basis of the composite was characterized by VSM, TGA, SEM, XRD, and FT-IR analytical methods.
    The antibacterial activities of Copper, Silver and Gold... 

    Biodegradation of synthetic dye using partially purified and characterized laccase and its proposed mechanism

    , Article International Journal of Environmental Science and Technology ; Volume 16, Issue 12 , 2019 , Pages 7805-7816 ; 17351472 (ISSN) Ghobadi Nejad, Z ; Borghei, S. M ; Yaghmaei, S ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2019
    The supernatant obtained from the extracellular laccase produced by Phanerochaete chrysosporium was used as the enzyme source to conduct a partial purification, characterization and dye decolorization study. The partially purified enzyme was stable in the pH range of 3–5 and showed an optimum activity at pH 4.0, using guaiacol as a substrate. Laccase stability of pH was determined and discovered to retain 100% of its activity at a pH of 4.0 after 2 h. The maximum enzyme activity was obtained between 30 and 50 °C. The maximum velocity and Michaelis constant were calculated as 3.171 µM−1·min and 1628.23 µM, respectively. The enzyme was activated by Fe2+, Zn2+, Ca2+ and Cu2+, while Hg2+, Mn2+,... 

    Smart chip for visual detection of bacteria using the electrochromic properties of polyaniline

    , Article Analytical Chemistry ; Volume 91, Issue 23 , 2019 , Pages 14960-14966 ; 00032700 (ISSN) Ranjbar, S ; Farahmand Nejad, M. A ; Parolo, C ; Shahrokhian, S ; Merkoci, A ; Sharif University of Technology
    American Chemical Society  2019
    Finding fast and reliable ways to detect pathogenic bacteria is crucial for addressing serious public health issues in clinical, environmental, and food settings. Here, we present a novel assay based on the conversion of an electrochemical signal into a more convenient optical readout for the visual detection of Escherichia coli. Electropolymerizing polyaniline (PANI) on an indium tin oxide screen-printed electrode (ITO SPE), we achieved not only the desired electrochromic behavior but also a convenient way to modify the electrode surface with antibodies (taking advantage of the many amine groups of PANI). Applying a constant potential to the PANI-modified ITO SPE induces a change in their...