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    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)
    Abstract
    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 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)
    Abstract
    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 of Zeolite-Based NanoComposites and Investigation of their Catalytic Activities

    , M.Sc. Thesis Sharif University of Technology Padervand, Mohsen (Author) ; Gholami, Mohammad Reza (Supervisor)
    Abstract
    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... 

    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)
    Abstract
    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... 

    Synthesis of Antibacterial Nanoparticle for Packaging Food Application

    , M.Sc. Thesis Sharif University of Technology Radan, Niloofar (Author) ; Yaghmaei, Soheila (Supervisor) ; Ghobadinezhad, Zahra (Co-Supervisor)
    Abstract
    Food spoilage cased by food-borne pathogens and microorganisms is a serious problem in the food and packaging industry. Then, the demand for antibacterial agents in food packaging is growing. The antibacterial efficacy of some nanocomposites has been recognized and exploited in various industries, including the packaging industry. Also, metal organic frameworks due to their porous structure, are used in various fields such as food packaging. The purpose of this work, is synthesize hybrid nanocomposite that have promising antibacterial activity for preparation of food packaging films. Carboxymethyl cellulose is a derivative of cellulose fiber. The use of carboxymethyl cellulose as... 

    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)
    Abstract
    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... 

    Synthesis, Characterization and Applications of Antibacterial Metal-Organic Framework Nanocomposites for Water Remediation

    , M.Sc. Thesis Sharif University of Technology Talebi Deylamani, Sara (Author) ; Borghei, Mehdi (Supervisor) ; Yaghmaei, Soheila (Supervisor) ; Ghobadi Nejad, Zahra (Co-Supervisor)
    Abstract
    Contaminants in drinking water, including microbial contaminants, have a great impact on the health of people in the community and can seriously threaten public health. In recent years, diseases caused by pathogenic bacteria due to the consumption of contaminated water have led to many deaths. As a result, water treatment has been one of the most important human concerns. Among the new water treatment technologies, metal-organic(MOF) frameworks are a new generation of porous materials that have properties such as high surface area, water stability and functionality due to their dual structure. As a result, they are widely used today in various scientific fields, including water purification.... 

    Optimization for Production & Purification of Asparaginase Enzyme

    , M.Sc. Thesis Sharif University of Technology Dashtban Kenari, Laleh (Author) ; Alemzadeh, Iran (Supervisor) ; Maghsodi, Vida (Supervisor)
    Abstract
    The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) 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,... 

    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)
    Abstract
    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... 

    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)
    Abstract
    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... 

    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)
    Abstract
    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... 

    , M.Sc. Thesis Sharif University of Technology Aftabi, Abed (Author) ; Yaghmaei, Soheyla (Supervisor) ; Maghsoudi, Vida (Supervisor)
    Abstract
    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... 

    Wrapping bacteria by graphene nanosheets for isolation from environment, reactivation by sonication, and inactivation by near-infrared irradiation

    , Article Journal of Physical Chemistry B ; Volume 115, Issue 19 , 2011 , Pages 6279-6288 ; 15206106 (ISSN) Akhavan, O ; Ghaderi, E ; Esfandiar, A ; Sharif University of Technology
    American Chemical Society  2011
    Abstract
    Bioactivity of Escherichia coli bacteria (as a simple model for microorganisms) and interaction of them with the environment were controlled by their capturing within aggregated graphene nanosheets. The oxygen-containing functional groups of chemically exfoliated single-layer graphene oxide nanosheets were reduced by melatonin as a biocompatible antioxidant. While each one of the graphene (oxide) suspension and melatonin solution did not separately show any considerable inactivation effects on the bacteria, aggregation of the sheets in the melatonin-bacterial suspension resulted in trapping the bacteria within the aggregated sheets, i.e., a kind of inactivation. The bacteria trapped within... 

    Visible light photo-induced antibacterial activity of CNT-doped TiO 2 thin films with various CNT contents

    , Article Journal of Materials Chemistry ; Volume 20, Issue 35 , Jun , 2010 , Pages 7386-7392 ; 09599428 (ISSN) Akhavan, O ; Azimirad, R ; Safa, S ; Larijani, M. M ; Sharif University of Technology
    2010
    Abstract
    Carbon nanotube (CNT)-doped TiO2 thin films with various CNT contents were synthesized by sol-gel method for visible light photoinactivation of Escherichia coli bacteria. Post annealing of the CNT-doped TiO2 thin films at 450 °C resulted in anatase TiO2 and formation of Ti-C and Ti-O-C carbonaceous bonds in the film. By increasing the CNT content, the thin films could further inactivate the bacteria in the dark. Meanwhile, as the CNT content increased from zero to 40 wt% the effective optical band gap energy of the CNT-doped TiO2 thin films annealed at 450 °C decreased from 3.2-3.3 to less than ∼2.8 eV providing light absorption in the visible region. Concerning this, visible light... 

    Visible light photoinactivation of bacteria by tungsten oxide nanostructures formed on a tungsten foil

    , Article Applied Surface Science ; Volume 338 , May , 2015 , Pages 55-60 ; 01694332 (ISSN) Ghasempour, F ; Azimirad, R ; Amini, A ; Akhavan, O ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Antibacterial activity of tungsten oxide nanorods/microrods were studied against Escherichia coli bacteria under visible light irradiation and in dark. A two-step annealing process at temperatures up to 390 °C and 400-800 °C was applied to synthesize the tungsten oxide nanorods/microrods on tungsten foils using KOH as a catalyst. Annealing the foils at 400 °C in the presence of catalyst resulted in formation of tungsten oxide nanorods (with diameters of 50-90 nm and crystalline phase of WO3) on surface of tungsten foils. By increasing the annealing temperature up to 800 °C, tungsten oxide microrods with K2W6O19 crystalline phase were formed on the foils. The WO3 nanorods showed a strong... 

    Vertically aligned ZnO@CdS nanorod heterostructures for visible light photoinactivation of bacteria

    , Article Journal of Alloys and Compounds ; Vol. 590 , 2014 , pp. 507-513 ; ISSN: 09258388 Zirak, M ; Akhavan, O ; Moradlou, O ; Nien, Y. T ; Moshfegh, A. Z ; Sharif University of Technology
    Abstract
    Vertically aligned ZnO@CdS nanorod heterostructure films with various loadings of CdS nanoparticle shell were synthesized and applied in photoinactivation of Escherichia coli bacteria under visible light irradiation. While neither the bare ZnO nanorods (with band-gap energy (Eg) of ∼3.28 eV) under visible light irradiation nor the nanorod heterostructures in dark exhibited any significant antibacterial activity, the ZnO@CdS nanorod heterostructures (with Eg ∼2.5-2.6 eV) could successfully inactivate the bacteria under visible light irradiation. Furthermore, it was found that an optimum loading of the CdS shell (corresponding to the effective thickness less than ∼15 nm) is required to achieve... 

    Toxicity of graphene and graphene oxide nanowalls against bacteria

    , Article ACS Nano ; Volume 4, Issue 10 , October , 2010 , Pages 5731-5736 ; 19360851 (ISSN) Akhavan, O ; Ghaderi, E ; Sharif University of Technology
    2010
    Abstract
    Bacterial toxicity of graphene nanosheets in the form of graphene nanowalls deposited on stainless steel substrates was investigated for both Gram-positive and Gram-negative models of bacteria. The graphene oxide nanowalls were obtained by electrophoretic deposition of Mg2+-graphene oxide nanosheets synthesized by a chemical exfoliation method. On the basis of measuring the efflux of cytoplasmic materials of the bacteria, it was found that the cell membrane damage of the bacteria caused by direct contact of the bacteria with the extremely sharp edges of the nanowalls was the effective mechanism in the bacterial inactivation. In this regard, the Gram-negative Escherichia coli bacteria with an... 

    Thickness dependent activity of nanostructured TiO2/α- Fe2O3 photocatalyst thin films

    , Article Applied Surface Science ; Volume 257, Issue 5 , 2010 , Pages 1724-1728 ; 01694332 (ISSN) Akhavan, O ; Sharif University of Technology
    2010
    Abstract
    The effect of thickness of TiO2 coating on synergistic photocatalytic activity of TiO2 (anatase)/α-Fe 2O3/glass thin films as photocatalysts for degradation of Escherichia coli bacteria in a low-concentration H2O2 solution and under visible light irradiation was investigated. Nanograined α-Fe2O3 films with optical band-gap of 2.06 eV were fabricated by post-annealing of thermal evaporated iron oxide thin films at 400 °C in air. Increase in thickness of the Fe2O3 thin film (here, up to 200 nm) resulted in a slight reduction of the optical band-gap energy and an increase in the photoinactivation of the bacteria. Sol-gel TiO2 coatings were deposited on the α-Fe2O 3 (200 nm)/glass films, and... 

    Thermochemical properties of some vinyl chloride-induced DNA lesions: Detailed view from NBO & AIM analysis

    , Article Structural Chemistry ; Volume 23, Issue 6 , 2012 , Pages 1987-2001 ; 10400400 (ISSN) Tehrani, Z. A ; Torabifard, H ; Fattahi, A ; Sharif University of Technology
    2012
    Abstract
    Etheno-damaged DNA adducts such as 3,N4- ethenocytosine, N 2,3-ethenoguanine, and 1,N2-ethenoguanine are associated with carcinogenesis and cell death. These inevitable damages are counteracted by glycosylase enzymes, which cleave damaged nucleobases from DNA. Escherichia coli alkyl purine DNA glycosylase is the enzyme responsible for excising damaged etheno adducts from DNA in humans. In an effort to understand the intrinsic properties of these molecules, we examined gasphase acidity values and proton affinities (PA) of multiple sites of these molecules as well as equilibrium tautomerization and base pairing properties by quantum mechanical calculations. We also used calculations to compare... 

    The performances of the chi-square test and complexity measures for signal recognition in biological sequences

    , Article Journal of Theoretical Biology ; Volume 251, Issue 2 , 2008 , Pages 380-387 ; 00225193 (ISSN) Pirhaji, L ; Kargar, M ; Sheari, A ; Poormohammadi, H ; Sadeghi, M ; Pezeshk, H ; Eslahchi, C ; Sharif University of Technology
    2008
    Abstract
    With large amounts of experimental data, modern molecular biology needs appropriate methods to deal with biological sequences. In this work, we apply a statistical method (Pearson's chi-square test) to recognize the signals appear in the whole genome of the Escherichia coli. To show the effectiveness of the method, we compare the Pearson's chi-square test with linguistic complexity on the complete genome of E. coli. The results suggest that Pearson's chi-square test is an efficient method for distinguishing genes (coding regions) form pseudogenes (noncoding regions). On the other hand, the performance of the linguistic complexity is much lower than the chi-square test method. We also use the...