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    Effect of particle size on the in vitro bioactivity, hydrophilicity and mechanical properties of bioactive glass-reinforced polycaprolactone composites [electronic resource]

    , Article Journal of Materials Science and Engineering: C ; 10 October 2011, Volume 31, Issue 7, Pages 1526–1533 Tamjid, E ; Bagheri, R ; Vossoughi, M ; Simchi, A. (Abdolreza) ; Sharif University of Technology
    Abstract
    Polycaprolactone (PCL) composite films containing 5 wt.% bioactive glass (BG) particles of different sizes (6 μm, 250 nm, < 100 nm) were prepared by solvent casting methods. The ultra-fine BG particles were prepared by high-energy mechanical milling of commercial 45S5 Bioglass® particles. The characteristics of bioactive glass particles were studied by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD) methods. In vitro bioactivity of the PCL/BG composite films was evaluated through immersion in the simulated body fluid (SBF). The films were analyzed by FE-SEM, energy dispersive... 

    Fabrication and characterization of a polysulfone-graphene oxide nanocomposite membrane for arsenate rejection from water

    , Article Journal of Environmental Health Science and Engineering ; Volume 13, Issue 1 , 2015 ; 2052336X (ISSN) Rezaee, R ; Nasseri, S ; Mahvi, A. H ; Nabizadeh, R ; Mousavi, S. A ; Rashidi, A ; Jafari, A ; Nazmara, S ; Sharif University of Technology
    BioMed Central Ltd  2015
    Abstract
    Background: Nowadays, study and application of modified membranes for water treatment have been considered significantly. The aim of this study was to prepare and characterize a polysulfone (PSF)/graphene oxide (GO) nanocomposite membrane and to evaluate for arsenate rejection from water. Materials and methods: The nanocomposite PSF/GO membrane was fabricated using wet phase inversion method. The effect of GO on the synthesized membrane morphology and hydrophilicity was studied by using FE-SEM, AFM, contact angle, zeta potential, porosity and pore size tests. The membrane performance was also evaluated in terms of pure water flux and arsenate rejection. Results: ATR-FTIR confirmed the... 

    The photoinduced activity of Ni-TiO2/TiO2 multilayer nanocomposites synthesized by pulse electrodeposition technique

    , Article International Journal of Electrochemical Science ; Volume 12, Issue 6 , 2017 , Pages 5121-5141 ; 14523981 (ISSN) Mohajeri, S ; Dolati, A ; Ghorbani, M ; Sharif University of Technology
    Abstract
    The sol-enhanced pulse plating (PP) technique was utilized to deposit the Ni-TiO2/TiO2 multilayers on copper substrates from a Watts bath containing a TiO2 sol, and the obtained coatings were heat treated at various temperatures. The characteristics of coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectrophotometry. In order to estimate the wettability of these nanostructured multilayers after exposure to UV light, the contact angle of water droplets were measured, and the photocatalytic (PC) efficiency of the multilayers were analyzed by the degradation of methyl... 

    Super-hydrophilic characteristic of thermochemically prepared CdS nanocrystals

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Vol. 58 , April , 2014 , pp. 146-152 ; ISSN: 13869477 Marandi, M ; Taghavinia, N ; Babaei, A ; Sharif University of Technology
    Abstract
    CdS nanocrystals were thermochemically (thermally activated) synthesized thorough the reaction between CdSO4 and Na2S 2O3 in an aqueous solution. Thioglycolic Acid (TGA) was used as the capping agent and catalyst of the reaction. The method was based on heat activated dissociation of Na2S2O3 and controllable release of S and free electrons in the solution. CdS NCs were formed by heating the sample solution at 96 C for 1 h. The results of optical spectroscopy and transmission electron microscopy demonstrated round shape NCs with sizes about 3.0 nm. The nanocrystals were also luminescent and represented a broad emission with a peak located at 515 nm and FWHM of 160 nm. Several samples were... 

    Rolled graphene oxide foams as three-dimensional scaffolds for growth of neural fibers using electrical stimulation of stem cells

    , Article Carbon ; Volume 97 , 2016 , Pages 71-77 ; 00086223 (ISSN) Akhavan, O ; Ghaderi, E ; Shirazian, S. A ; Rahighi, R ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    Graphene oxide foam (GOF) layers with thicknesses of ∼15-50 μm and density of ∼10 graphene oxide (GO) sheets/μm were fabricated by precipitation of chemically exfoliated GO sheets in an aqueous suspension at ∼80 °C under UV irradiation. Then, rolled GOFs with desirable scales were developed as electrically conductive 3D-scaffolds and applied in directional growth of neural fibers, through differentiation of human neural stem cells (hNSCs) into neurons under an electrical stimulation. X-ray photoelectron spectroscopy indicated that the UV irradiation resulted in partial deoxygenation of the layers. Scanning electron microscopy and Raman spectroscopy confirmed the presence of multilayer GO... 

    Near-white emitting QD-LED based on hydrophilic CdS nanocrystals

    , Article Journal of Luminescence ; Volume 132, Issue 2 , 2012 , Pages 467-473 ; 00222313 (ISSN) Molaei, M ; Marandi, M ; Saievar Iranizad, E ; Taghavinia, N ; Liu, B ; Sun, H. D ; Sun, X. W ; Sharif University of Technology
    Abstract
    In this work we report fabrication of a nanocrystal (NC)-based hybrid organicinorganic LED with structure of ITO/PEDOT:PSS/PVK/CdS-NCs/(Al or Mg:Ag). The hydrophilic CdS NCs were synthesized using a novel aqueous thermochemical method at 80 °C and sizes (around 2 nm) were controlled by thioglycolic acid (TGA) as the capping agent. The favorite feature of these NCs is their relatively high emission intensity and broad, near-white emission. The hydrophilic CdS NCs were successfully spin coated using Triton X-100 as the wetting agent. The fabricated LEDs demonstrated a turn on voltage about 7 V for Al metallic contact. The electroluminescence was a broad spectrum at 540 and 170 nm width, which... 

    The impact of MOF feasibility to improve the desalination performance and antifouling properties of FO membranes

    , Article RSC Advances ; Volume 6, Issue 74 , 2016 , Pages 70174-70185 ; 20462069 (ISSN) Zirehpour, A ; Rahimpour, A ; Khoshhal, S ; Firouzjaei, M. D ; Ghoreyshi, A. A ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Abstract
    In this study, a hydrophilic metal-organic framework (MOF) was applied to improve the performance of a cellulosic membrane for forward osmosis (FO) desalination application. The characterization results confirmed that the MOF particles existed within the matrix of the modified membrane. The MOF loading led to adjustment of the membranes in terms of overall porosity, pore inter-connectivity and hydrophilicity. These features caused an improvement in the pure water permeability (72%) and reduce the structural parameter of the modified membrane to 136 μm. The FO water flux of the modified membrane enhanced by about 180% compared to an unmodified membrane, without decreasing its selectivity. FO... 

    Influence of surface-modified nanoparticles on the hydrodynamics of rising bubbles

    , Article Chemical Engineering and Technology ; Volume 44, Issue 3 , 2021 , Pages 513-520 ; 09307516 (ISSN) Fayzi, P ; Bastani, D ; Lotfi, M ; Miller, R ; Sharif University of Technology
    Wiley-VCH Verlag  2021
    Abstract
    Local velocities of bubbles rising in four different nanosilica solutions were investigated experimentally. Also, the density, viscosity, and surface tension of fumed nanosilica and modified nanosilica solutions were measured. Heat treatment and chemical functionalization were used to modify the properties of silica nanoparticles. It was found that the addition of nanosilica affected the hydrodynamics of the rising bubble by increasing the drag friction at the interface. However, environmentally responsive nanosilica particles behaved like surfactant molecules, due to the interfacial activity of hydrophilic and hydrophobic chains. Silica nanoparticles coated with both hydrophilic and... 

    Albumin-graphene oxide conjugates; Carriers for anticancer drugs

    , Article RSC Advances ; Vol. 4, issue. 62 , July , 2014 , pp. 33001-33006 ; ISSN: 20462069 Jokar, S ; Pourjavadi, A ; Adeli, M ; Sharif University of Technology
    Abstract
    In order to improve its biological properties, graphene oxide can be modified with hydrophilic polymers. Therefore, in this study, the surface of graphene oxide was modified with polyethylene glycol and albumin by covalent methods. In the subsequent step, paclitaxel which is a hydrophobic anticancer drug was loaded onto the surface of the functionalized graphene by π-π interactions. The synthesis of the nanocarrier and its interaction with paclitaxel were evaluated by FT-IR, CD, TEM, UV, AFM, DLS and fluorescence experiments. Release of the loaded drug from albumin-graphene conjugate was investigated at pH 5.4, 6.8 and 7.4  

    Effect of TiO2 nanoparticles on antifouling and separation properties of PVDF/PAN blend membrane

    , Article Desalination and Water Treatment ; Volume 154 , 2019 , Pages 92-100 ; 19443994 (ISSN) Anvari, A ; Azimi Yancheshme, A ; Tavakolmoghadam, M ; Rekabdar, F ; Safekordi, A ; Sharif University of Technology
    Desalination Publications  2019
    Abstract
    Recently, membrane fouling has been one of the most important issues in the field of membrane technology. In this regard, TiO2 nanoparticles blended with polymeric membranes have shown to improve fouling performance. In this study, a new PVDF/PAN/TiO2 ultrafiltration blend membrane was prepared via phase inversion by dispersing TiO2 nanoparticles in the PVDF/PAN casting solutions. The effect of different concentrations of TiO2 on the characteristics of membranes (i.e., morphology, hydrophilicity, permeation performance, and antifouling properties) was investigated. Results of scanning electron microscopy analysis showed the finger-like pores and macrovoids decrease due to the presence of... 

    Physiological temperature has a crucial role in amyloid beta in the absence and presence of hydrophobic and hydrophilic nanoparticles

    , Article ACS Chemical Neuroscience ; Volume 4, Issue 3 , December , 2013 , Pages 375-378 ; 19487193 (ISSN) Ghavami, M ; Rezaei, M ; Ejtehadi, R ; Lotfi, M ; Shokrgozar, M. A ; Abd Emamy, B ; Raush, J ; Mahmoudi, M ; Sharif University of Technology
    2013
    Abstract
    Amyloid beta fibrillation can lead to major disorder of neurons processes and is associated with several neuronal diseases (e.g., Alzheimer's disease). We report here an importance of slight temperature changes, in the physiological range (35-42 °C), on the amyloid fibrillation process in the presence and absence of hydrophilic (silica) and hydrophobic (polystyrene) nanoparticles (NPs). The results highlight the fact that slight increases in temperature can induce inhibitory and acceleratory effects of hydrophobic and hydrophilic NPs on the fibrillation process, respectively. Using further in vivo considerations, the outcomes of this study can be used for considerable modifications on the... 

    Improvements in permeation and fouling resistance of PVC ultrafiltration membranes via addition of Tetronic-1107 and Triton X-100 as two non-ionic and hydrophilic surfactants

    , Article Water Science and Technology ; Volume 74, Issue 6 , 2016 , Pages 1469-1483 ; 02731223 (ISSN) Rabiee, H ; Seyedi, S. M ; Rabiei, H ; Alvandifar, N ; Sharif University of Technology
    IWA Publishing 
    Abstract
    Two non-ionic and hydrophilic surfactant additives, Tetronic-1107 and Triton X-100, were added to poly(vinyl chloride)/NMP polymeric solution to prepare ultrafiltration membranes via immersion precipitation. Surfactants at three different weight percentages up to 6 wt% were added, and the fabricated membranes were characterized and their performance for water treatment in the presence of bovine serum albumin (BSA) as a foulant was assessed. The scanning electron microscopy images indicated remarkable changes in morphology due to higher thermodynamic instability after surfactant addition. The membranes are more porous with more macro-voids in the sub-layer. Plus, the membranes become more... 

    An exploratory study on application of various classification models to distinguish switchable-hydrophilicity solvents based on 3D-descriptors

    , Article Separation Science and Technology (Philadelphia) ; 2020 Shiri, M ; Shiri, F ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Abstract
    A set of solvents were classified into the switchable-hydrophilicity solvents (SHSs) and non-switchable-hydrophilicity solvents based on forming or not forming a biphasic mixture with water. SHSs have been developed to make the reaction and product separation processes easier. Herein, three classifier algorithms and various feature selection techniques relay on 3D-molecular descriptors to characterize chemicals and forecast their classes were employed. Cfs-SVM method was employed to perform a classification study. The importance of this study helps to understand more about the presence of hydrophobic groups, their position, and their shape in the molecule. © 2020, © 2020 Taylor & Francis... 

    Hydrophilicity variation of WO3 thin films with annealing temperature

    , Article Journal of Physics D: Applied Physics ; Volume 40, Issue 4 , 2007 , Pages 1134-1137 ; 00223727 (ISSN) Azimirad, R ; Naseri, N ; Akhavan, O ; Moshfegh, A. Z ; Sharif University of Technology
    2007
    Abstract
    The influence of annealing temperature on the hydrophilic property of WO3 thin films deposited by thermal evaporation and sol-gel dip-coating methods was studied and compared for the first time. The thermal evaporated WO3 thin films annealed at 400 °C showed a nearly super-hydrophilic property without UV and visible illumination. By analysing the O(1s) core level peak of XPS spectra, the amount of oxygen contributed at various bonds (including O2-, OH- and H2O) on the surface of the annealed samples at different temperatures were measured. In addition, a correlation between the hydrophilicity and the concentration of chemisorbed water on the film surface was suggested, independent of the... 

    Modified CMC. V. synthesis and super-swelling behavior of hydrolyzed CMC-g-PAN hydrogel

    , Article Journal of Applied Polymer Science ; Volume 103, Issue 2 , 2007 , Pages 877-883 ; 00218995 (ISSN) Pourjavadi, A ; Zohuriaan Mehr, M. J ; Ghasempoori, S. N ; Hossienzadeh, H ; Sharif University of Technology
    2007
    Abstract
    Polyacrylonitrile (PAN) was grafted onto carboxymethyl cellulose (CMC) sodium salt backbones by using cerie ammonium nitrate (CAN) as an initiator. The graft co-polymer, CMC-g-PAN, was hydrolyzed by NaOH solution to yield hydrogel, H-CMC-g-PAN. The nitrile groups of CMC-g-PAN were completely converted to a mixture of hydrophilic carboxamide and carboxylate groups during alkaline hydrolysis, followed by in situ crosslinking of the grafted PAN chains. The structure of the products was confirmed by FTIR spectroscopy. The synthetic parameters affecting the swelling capacity of the hydrogel (i.e., CMC-g-PAN add-on value, the hydrolysis time and temperature, and concentration of NaOH) were... 

    Aluminum coatings on cotton fabrics with low temperature plasma of argon and oxygen

    , Article Surface and Coatings Technology ; Volume 201, Issue 9-11 SPEC. ISS , 2007 , Pages 5646-5650 ; 02578972 (ISSN) Shahidi, S ; Ghoranneviss, M ; Moazzenchi, B ; Anvari, A ; Rashidi, A ; Sharif University of Technology
    2007
    Abstract
    In this article, we have studied the properties (especially water repellency) of cotton coated by a thin layer of aluminum. The process has been performed in a low temperature plasma medium, using a magnetron sputtering device. We have also investigated the effect of different gases such as argon and oxygen as the discharge medium on the properties of the obtained samples. The results which are exposure time dependent show a good repellent property for 30 min of treating in argon medium under the condition of our experiment. However, when O2 is used in the system, the cotton property changes to become hydrophilic of which the factor decreases as we increase the time of treating. © 2006... 

    Facile synthesis of cauliflower-like hydrophobically modified polyacrylamide nanospheres by aerosol-photopolymerization

    , Article European Polymer Journal ; Volume 83 , 2016 , Pages 323-336 ; 00143057 (ISSN) Shaban, M ; Ramazani, S. A. A ; Ahadian, M. M ; Tamsilian, Y ; Weber, A. P ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    Amphiphilic copolymers consist of hydrophilic and hydrophobic monomer units have attracted great technological attention recently, owing to their unique properties and their ability to stabilize various interfaces in aqueous systems. This paper presents a novel and facile approach to produce spherical polyacrylamide, polystyrene and hydrophobically modified polyacrylamide (HM-PAM), as one of the most important type of amphiphilic copolymers, using a continuous aerosol-photopolymerization for the first time. To this end, the monomer droplets were generated by an atomizer, then photopolymerization was initiated ‘‘in flight’’ by ultraviolet (UV) irradiation of the aerosol monomer droplets... 

    Surface chemistry of atmospheric plasma modified polycarbonate substrates

    , Article Applied Surface Science ; Volume 257, Issue 23 , September , 2011 , Pages 9836-9839 ; 01694332 (ISSN) Yaghoubi, H ; Taghavinia, N ; Sharif University of Technology
    2011
    Abstract
    Surface of polycarbonate substrates were activated by atmospheric plasma torch using different gas pressure, distance from the substrates, velocity of the torch and number of treatments. The modifications were analyzed by contact angle measurements, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and UV-vis spectrophotometry. Plasma treatment caused the surface characteristics to become more hydrophilic as measured by the water contact angle, which decreased from 88° to 18°. The decrease in contact angle was mainly due to oxidation of the surface groups, leading to formation of polar groups with hydrophilic property. XPS results showed an increase in the intensity of... 

    Superhydrophilic stability enhancement of RF co-sputtered TixSi1-xO2 thin films in dark

    , Article Applied Surface Science ; Volume 256, Issue 8 , 2010 , Pages 2500-2506 ; 01694332 (ISSN) Mirshekari, M ; Azimirad, R ; Moshfegh, A. Z ; Sharif University of Technology
    2010
    Abstract
    TixSi1-xO2 compound thin-film systems were deposited by reactive RF magnetron co-sputtering technique. The effect of Ti concentration on the hydrophilicity of TixSi1-xO2 compound thin films was studied and it was shown that the films with Ti0.6Si0.4O2 composition possess the best hydrophilic property among all the grown samples. Surface ratio and average roughness of the thin films were measured by atomic force microscopy (AFM). Surface chemical states and stoichiometry of the films were determined by X-ray photoelectron spectroscopy (XPS). In addition, XPS revealed that the amount of Ti-O-Si bonds in nanometer depth from the surface of the Ti0.6Si0.4O2 films was the maximum, which resulted... 

    Lipid membranes with transmembrane proteins in shear flow

    , Article Journal of Chemical Physics ; Volume 132, Issue 2 , 2010 ; 00219606 (ISSN) Khoshnood, A ; Noguchi, H ; Gompper, G ; Sharif University of Technology
    Abstract
    The effects of embedded proteins on the dynamical properties of lipid bilayer membranes are studied in shear flow. Coarse-grained molecular simulations are employed, in which lipids are modeled as short polymers consisting of hydrophilic head groups and hydrophobic tail monomers; similarly, transmembrane proteins are modeled as connected hydrophobic double- or triple-chain molecules with hydrophilic groups at both ends. In thermal equilibrium, rigid proteinlike molecules aggregate in a membrane of flexible lipids, while flexible proteins do not aggregate. In shear flow parallel to the membrane, the monolayers of lipid bilayer slide over each other. The presence of transmembrane proteins...