Search for: escherichia-coli
0.009 seconds
Total 131 records

    Magnetic metal nanoparticles decorated ionic liquid with excellent antibacterial activity

    , Article Journal of Nanostructures ; Volume 10, Issue 3 , 2020 , Pages 613-623 Salari, H ; Karimi Asl, M ; Padervand, M ; Gholami, M. R ; Sharif University of Technology
    University of Kashan  2020
    Fe3O4 magnetic structure was synthesized with co-precipitation method. Surface of magnetic core was modified with hydrophobic BMIM[PF6] ionic liquid. The samples became antibacterial by loading gold, copper and silver nanoparticles and denoted as Fe3O4/IL/X (X=Ag, Au, Cu). X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), thermal gravimetric analysis (TGA), Atomic absorption spectroscopy (AAS), Fourier transform infrared (FTIR) and vibration sample magnetometer (VSM) technics were applied for catalysts characterization, metal concentration analysis and morphology monitoring. Modified nanostructures were used for inactivation of Escherichia coli as... 

    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
    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... 

    DNA and RNA extractions from eukaryotic and prokaryotic cells by graphene nanoplatelets

    , Article RSC Advances ; Vol. 4, issue. 105 , 2014 , p. 60720-60728 Hashemi, E ; Akhavan, O ; Shamsara, M ; Valimehr, S ; Rahighi, R ; Sharif University of Technology
    Graphene nanoplatelets with lateral dimensions of ∼50-200 nm and thicknesses <2 nm were utilized for the extraction of nucleic acids (NAs) from eukaryotic and prokaryotic cells. The graphene nanoplatelets (both chemically exfoliated graphene oxide nanoplatelets and hydrazine-reduced graphene oxide nanoplatelets) successfully extracted plasmid DNA (pDNA) from Escherichia coli bacteria, comparable to a conventional phenol-chloroform (PC) method. Furthermore, it was found that the yield of graphene nanoplatelets in genomic DNA (gDNA) and RNA extractions from embryonic stem cells (ESCs) was also comparable to the yield of the conventional methods. The effects of the graphene nanoplatelets on... 

    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
    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 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
    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... 

    , 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... 

    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... 

    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... 

    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... 

    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, 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)
    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.... 

    Photocatalytic mechanism of action of apatite-coated Ag=AgBr=TiO 2 on phenol and Escherichia coli and Bacillus subtilis bacteria under various conditions

    , Article Progress in Reaction Kinetics and Mechanism ; Vol. 1 , Vol.36 (1) , 2011 , pp.38-52 Elahifard, M. R. (Mohammad Reza) ; Gholami, M. R. (Mohammad Reza) ; Rahimnejad, S. (Sara) ; Pourbaba, R. (Reza) ; Haghighi, S.(Saeed) ; Sharif University Of Technology
    Multi-component photocatalysts based on apatite-coated Ag/AgBr/TiO(2) were prepared by the deposition method. The effects of various kinds of apatites, with hydroxyl and fluoro substituents, on photocatalytic activity were investigated. The antibacterial processes in the dark, and under visible light, on two types of bacteria indicate that the multi-composites can inhibit the growth of bacteria by two different mechanisms. TEM images and optical microscopic data demonstrate that by attaching the nanosize catalyst to the outer membrane of the cell, the bacteria could not derive nourishment from surrounding media, i.e. this component acts as bacteria-static. The mechanism for deactivation of... 

    An enhancement in the photocatalytic activity of TiO 2 by the use of Pd: The question of layer sequence in the resulting hierarchical structure

    , Article Journal of Coatings Technology Research ; Volume 8, Issue 1 , January , 2011 , Pages 75-81 ; 15470091 (ISSN) Rezaeian Delouei, M ; Ghorbani, M ; Mohsenzadeh, M ; Sharif University of Technology
    TiO 2 and Pd-modified TiO 2 photocatalysts were prepared by sol-gel method. X-ray diffraction (XRD) data showed that the presence of Pd in TiO 2 catalyst decreases the crystalline size of TiO 2 and stabilizes anatase phase. The study of the photocatalytic activity of the films via Linear Sweep Voltametry (LSV) plots and antibacterial test against Escherichia coli ATCC 25922-a gram negative bacterium-showed that Pd increases the photocatalytic activity of the coatings. Besides, the sequence of layer deposition (TiO 2 and Pd-modified TiO 2) influences the photocatalytic properties. In other words, more photocatalytic activity is obtained when Pd-modified layer is deposited first  

    Overcoming drug resistance by co-targeting

    , Article Proceedings - 2010 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2010, 18 December 2010 through 21 December 2010 ; December , 2010 , Pages 198-202 ; 9781424483075 (ISBN) Ayati, M ; Taheri, G ; Arab, S ; Wong, L ; Eslahchi, C ; Sharif University of Technology
    Removal or suppression of key proteins in an essential pathway of a pathogen is expected to disrupt the pathway and prohibit the pathogen from performing a vital function. Thus disconnecting multiple essential pathways should disrupt the survival of a pathogen even when it has multiple pathways to drug resistance. We consider a scenario where the drug-resistance pathways are unknown. To disrupt these pathways, we consider a cut set S of G, where G is a connected simple graph representing the protein interaction network of the pathogen, so that G-S splits to two partitions such that the endpoints of each pathway are in different partitions. If the difference between the sizes of the two... 

    Denoising of genetic switches based on Parrondo's paradox

    , Article Physica A: Statistical Mechanics and its Applications ; Volume 493 , 2018 , Pages 410-420 ; 03784371 (ISSN) Fotoohinasab, A ; Fatemizadeh, E ; Pezeshk, H ; Sadeghi, M ; Sharif University of Technology
    Elsevier B.V  2018
    Random decision making in genetic switches can be modeled as tossing a biased coin. In other word, each genetic switch can be considered as a game in which the reactive elements compete with each other to increase their molecular concentrations. The existence of a very small number of reactive element molecules has caused the neglect of effects of noise to be inevitable. Noise can lead to undesirable cell fate in cellular differentiation processes. In this paper, we study the robustness to noise in genetic switches by considering another switch to have a new gene regulatory network (GRN) in which both switches have been affected by the same noise and for this purpose, we will use Parrondo's... 

    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... 

    Rosmarinus officinalis directed palladium nanoparticle synthesis: Investigation of potential anti-bacterial, anti-fungal and Mizoroki-Heck catalytic activities

    , Article Advanced Powder Technology ; Volume 31, Issue 4 , 2020 , Pages 1402-1411 Rabiee, N ; Bagherzadeh, M ; Kiani, M ; Ghadiri, A. M ; Sharif University of Technology
    Elsevier B.V  2020
    The present work was aimed to account a green and eco-friendly synthesis of palladium nanoparticles using Rosmarinus officinalis leaves extracts for the first time, therefore, that can be an acceptable replacement for chemical media to improve potential biological properties. The synthesized palladium nanoparticles were fully characterized using FT-IR, XRD, FESEM, TEM and UV/Vis spectroscopy techniques. Catalytic activity was investigated by Mizoroki-Heck reaction, and optimized based on solvent, temperature and time of the reaction, and the best results were found in water as a green media without any additional reagents. Biological activity of the synthesized nanoparticles were evaluated... 

    Dextran-graft-poly(hydroxyethyl methacrylate) gels: A new biosorbent for fluoride removal of water

    , Article Designed Monomers and Polymers ; Volume 16, Issue 2 , 2013 , Pages 127-136 ; 1385772X (ISSN) Ahmari, A ; Mousavi, S. A ; Amini Fazl, A ; Amini Fazl, M. S ; Ahmari, R ; Sharif University of Technology
    Synthesis of dextran-graft-poly(hydroxyethyl methacrylate) gels as a new fluoride biosorbent was considered in this work. For this propose, the Taguchi experimental design method was used for optimizing the synthetic conditions of the gels to reach high level of fluoride absorbency. The effects of three main parameters including concentrations of monomer (hydroxyethyl methacrylate), crosslinking agent (ethylene glycol dimethacrylate), and initiator (ammonium persulfate) on the final properties of the prepared gels were investigated. The proposed mechanism for grafting and chemically crosslinking reactions was proved with equilibrium water absorption, Fourier-transformed infrared, scanning...