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    Different PES nanofibrous membrane parameters effect on the efficacy of immunoassay performance

    , Article Polymers for Advanced Technologies ; Volume 30, Issue 8 , 2019 , Pages 1968-1977 ; 10427147 (ISSN) Mahmoudifard, M ; Vossoughi, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    Abstract
    The contribution of electrospun nanofibrous membranes (e.NFMs) in the biosensing platforms opens up a new prospect for the invention of faster and more sensitive analytical devices. In this paper, we utilized e.NFM of polyethersulfone (PES) as a solid substrate for the protein immobilization through two different approaches: physical and covalent. Scanning electron microscopy (SEM) and Fourier-transform-infrared (FTIR) tests were performed to study the effect of plasma treatment on protein immobilization efficacy. Moreover, taking advantage of ELISA technique, the influence of different parameters, namely, nanofibers diameter, membrane thickness, plasma treatment time, an incubation time of... 

    Polymeric like carbon films prepared from liquid gas and the effect of nitrogen

    , Article Applied Surface Science ; Volume 254, Issue 20 , 15 August , 2008 , Pages 6441-6445 ; 01694332 (ISSN) Ghodselahi, T ; Vesaghi, M. A ; Sharif University of Technology
    Elsevier  2008
    Abstract
    Polymeric like carbon (PLC) films are grown by a capacitance coupled RF-PECVD on the grounded electrode at room temperature from liquid gas (40% propane and 60% butane) in two regimes with nitrogen and without nitrogen gas. Films are characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Fourier transform infrared (FTIR) absorption and Raman spectroscopy. The result of FTIR analyses indicates that more than 90% of hydrogen atoms are bonded to carbon with sp 3 hybridization. The abundance of CH 3 is more than that of CH 2 and this one is more than that of CH for carbon with sp 3 hybridization in these films. The C 1s line of the XPS spectra is deconvoluted to... 

    Salt- and pH-resisting collagen-based highly porous hydrogel

    , Article Polymer Journal ; Volume 40, Issue 2 , 2008 , Pages 94-103 ; 00323896 (ISSN) Pourjavadi, A ; Kurdtabar, M ; Ghasemzadeh, H ; Sharif University of Technology
    2008
    Abstract
    A novel approach was developed to prepare a highly porous hydrogel with superior salt- and pH-resisting properties. According to this method, synthetic comonomers, i.e. acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), were polymerized and crosslinked in the presence of hydrolyzed collagen as a natural backbone. The characterizations of hydrogels were investigated by swelling experiment, Fourier transform infrared (FT-IR) spectroscopy, acid-base titration and thermogravimetric analysis (TGA). Morphology of the samples was examined by scanning electron microscopy (SEM). Experimental results indicate that the hydrogel has an absorbency of 360 and 73-82 g/g for distilled... 

    Synthesis of novel water-soluble aminodeoxychitin derivatives

    , Article Starch/Staerke ; Volume 59, Issue 11 , 2007 , Pages 557-562 ; 00389056 (ISSN) Pourjavadi, A ; Seidi, F ; Salimi, H ; Sharif University of Technology
    2007
    Abstract
    Eight new chitin derivatives have been synthesized via SN2 reaction of primary and secondary amines with tosylchitin. The products were characterized using FTIR and 1H NMR spectroscopy. A degree of substitution ∼ 1 was achieved through this process. These materials are soluble in water at room temperature, which enable their further applications in the future. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA  

    Carrageenan-g-poly(acrylamide)/poly(vinylsulfonic acid, sodium salt) as a novel semi-IPN hydrogel: Synthesis, characterization, and swelling behavior

    , Article Polymer Engineering and Science ; Volume 47, Issue 9 , 2007 , Pages 1388-1395 ; 00323888 (ISSN) Pourjavadi, A ; Ghasemzadeh, H ; Sharif University of Technology
    2007
    Abstract
    A semi-interpenetrating polymer network (semi-IPN) hydrogel based on kappa-carrageenan (κC) and poly (vinylsulfonic acid, sodium salt) (PVSA) was prepared by graft copolymerization of acrylamide (AAm) using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. FTIR spectroscopy was used for confirming the structure of the final product. It was found that the chemical composition of the Semi-IPN hydrogel is equal to the initial homopolymers and monomer feed compositions. The swelling capacity of the hydrogel was shown to be affected by the MBA, APS, and AAm concentration as well as κC/PVSA weight ratio. The swelling behavior of the hydrogel was... 

    Synthesis, characterization and swelling behavior of gelatin-g-poly(sodium acrylate)/kaolin superabsorbent hydrogel composites

    , Article Journal of Composite Materials ; Volume 41, Issue 17 , 2007 , Pages 2057-2069 ; 00219983 (ISSN) Pourjavadi, A ; Hosseinzadeh, H ; Sadeghi, M ; Sharif University of Technology
    2007
    Abstract
    In the present paper, a novel superabsorbent hydrogel composite based on gelatin have been prepared via graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. Certain variables of the graft copolymerization (i.e., the monomer, the initiator, and the crosslinker concentration as well as kaolin/gelatin weight ratio) affected on the ultimate water-swelling capacity were optimized. The composite structure was confirmed using Fourier transform infrared (FTIR) spectroscopy. A new absorption band at 1728 cm1 in the composite spectrum confirmed kaolinorganic polymer... 

    Gelation time and degradation rate of chitosan-based injectable hydrogel

    , Article Journal of Sol-Gel Science and Technology ; Volume 42, Issue 1 , 2007 , Pages 47-53 ; 09280707 (ISSN) Ganji, F ; Abdekhodaie, M. J ; Ramazani S. A., A ; Sharif University of Technology
    2007
    Abstract
    Gelation time and degradation rate of thermally-sensitive aqueous solutions of chitosan/Gp (glycerophosphate disodium salt) have been studied. The effects of different parameters such as Gp salt concentration, solution temperature, degree of deacetylation of chitosan (DDA) and drug loading on the gelation time have been investigated. Gravimetric analysis, gel permeation chromatography and FTIR spectrophotometry were used to investigate the influence of the DDA and concentration of chitosan solution on hydrogel degradation. The presented results indicated that gelation time decreases by increasing Gp salt concentration, temperature, concentration and DDA of chitosan solutions, while drug... 

    Synthesis of an alginate-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with low salt sensitivity and high pH sensitivity

    , Article Journal of Applied Polymer Science ; Volume 101, Issue 5 , 2006 , Pages 2927-2937 ; 00218995 (ISSN) Bagheri Marandi, G ; Sharifnia, N ; Hosseinzadeh, H ; Sharif University of Technology
    2006
    Abstract
    This article describes the synthesis and swelling behavior of a superabsorbing hydrogel based on sodium alginate (NaAlg) and polyacrylonitrile (PAN). The physical mixture of NaAlg and PAN was hydrolyzed with a solution of NaOH to yield an alginate-poly(sodium acrylate-co-acrylamide) [Alg-poly(NaAA-co-AAm)] superabsorbent hydrogel. A proposed mechanism for hydrogel formation was suggested, and the structure of the product was established with Fourier transform infrared spectroscopy. The effects of reaction variables were systematically optimized to achieve a hydrogel with a swelling capacity as high as possible. Under the optimized conditions concluded, the maximum capacity of swelling in... 

    A convenient one-step preparation of chitosan-poly(sodium acrylate-co-acrylamide) hydrogel hybrids with super-swelling properties

    , Article Journal of Applied Polymer Science ; Volume 99, Issue 4 , 2006 , Pages 1615-1619 ; 00218995 (ISSN) Mahdavinia, G. R ; Pourjavadi, A ; Zohuriaan Mehr, M. J ; Sharif University of Technology
    2006
    Abstract
    Hydrogel hybrids were conveniently prepared from alkaline hydrolysis of chitosan-poly(acrylonitrile) mixture under highly practical conditions. The reaction of chitosan alkoxide anions with nitrile groups of poly(acrylonitrile) (PAN) forms crosslinking points and results in a three-dimensional network with superswelling ability in aqueous media. The hydrogel hybrid was identified using FTIR spectroscopy. The PAN content of the hydrolyzing feed affects proportionally the swelling capacity of the hydrogel hybrid. The swelling properties (capacity and rate) of the ampholytic hydrogel were investigated preliminarily. © 2005 Wiley Periodicals, Inc  

    CMC-g-poly (sodium acrylate)/kaolin superabsorbent hydrogel composites: Synthesis, characterization and swelling behaviour

    , Article Polymers and Polymer Composites ; Volume 14, Issue 7 , 2006 , Pages 701-712 ; 09673911 (ISSN) Pourjavadi, A ; Ghasemzadeh, H ; Sharif University of Technology
    Rapra Technology Ltd  2006
    Abstract
    A novel superabsorbent composite system based on carboxymethyl cellulose (CMC) was prepared by graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The effect of reaction variables, such as MBA, AA, and APS concentration and CMC/kaolin ratio on the water absorbency of the composite were studied. Evidence of grafting and kaolin interaction was obtained by comparing the FT-IR spectra of the initial substrates with that of the superabsorbent composite. The results indicated that with increasing amount of kaolin, the swelling capacity was increased and then... 

    Effect of polypropylene fibers and cement on the strength improvement of subgrade lying on expansive soil

    , Article Iranian Journal of Science and Technology - Transactions of Civil Engineering ; 2021 ; 22286160 (ISSN) Khan, S. Z ; Rehman, Z ; Khan, A. H ; Qamar, S ; Haider, F ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The current study revealed the effectiveness of polypropylene (PP) fibers and cement to enhance the strength of black cotton soil. PP fibers and cement with different concentrations were mixed with black cotton soil. The strength of PP fiber and cement-based soil samples was measured in terms of unconfined compressive strength (UCS) and California Bearing ratio (CBR). Specimens for UCS and CBR tests were prepared at 2%, 4%, 6% and 8% of cement (by dry weight of soil) and seven percentages of polypropylene fibers i.e. 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6% (by dry weight of soil). Fourier transform infrared (FTIR) analysis confirmed the presence of polypropylene and cement contents in... 

    Effect of polypropylene fibers and cement on the strength improvement of subgrade lying on expansive soil

    , Article Iranian Journal of Science and Technology - Transactions of Civil Engineering ; Volume 46, Issue 1 , 2022 , Pages 343-352 ; 22286160 (ISSN) Khan, S. Z ; Rehman, Z ; Khan, A. H ; Qamar, S ; Haider, F ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    The current study revealed the effectiveness of polypropylene (PP) fibers and cement to enhance the strength of black cotton soil. PP fibers and cement with different concentrations were mixed with black cotton soil. The strength of PP fiber and cement-based soil samples was measured in terms of unconfined compressive strength (UCS) and California Bearing ratio (CBR). Specimens for UCS and CBR tests were prepared at 2%, 4%, 6% and 8% of cement (by dry weight of soil) and seven percentages of polypropylene fibers i.e. 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6% (by dry weight of soil). Fourier transform infrared (FTIR) analysis confirmed the presence of polypropylene and cement contents in... 

    The nanofibrous PAN-PANi scaffold as an efficient substrate for skeletal muscle differentiation using satellite cells

    , Article Bioprocess and Biosystems Engineering ; Volume 39, Issue 7 , 2016 , Pages 1163-1172 ; 16157591 (ISSN) Hosseinzadeh, S ; Mahmoudifard, M ; Mohamadyar Toupkanlou, F ; Dodel, M ; Hajarizadeh, A ; Adabi, M ; Soleimani, M ; Sharif University of Technology
    Springer Verlag 
    Abstract
    Among polymers, polyaniline (PANi) has been introduced as a good candidate for muscle regeneration due to high conductivity and also biocompatibility. Herein, for the first time, we report the use of electrospun nanofibrous membrane of PAN-PANi as efficient scaffold for muscle regeneration. The prepared PAN-PANi electrospun nanofibrous membrane was characterized by scanning electron microscopy (SEM), Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) and tensile examination. The softer scaffolds of non-composite electrospun nanofibrous PAN govern a higher rate of cell growth in spite of lower differentiation value. On the other hand, PAN-PANi electrospun... 

    Thermodynamics of vanadium (V) solvent extraction by mixture of D2EHPA and TBP

    , Article International Journal of Mineral Processing ; Volume 138 , May , 2015 , Pages 49-54 ; 03017516 (ISSN) Cheraghi, A ; Ardakani, M. S ; Keshavarz Alamdari, E ; Haghshenas Fatmesari, D ; Darvishi, D ; Sadrnezhaad, S. K ; Sharif University of Technology
    Elsevier  2015
    Abstract
    In the present study, the thermodynamics and mechanisms of vanadium extraction by a mixture of bis-2-ethylhexyl phosphoric acid (D2EHPA) and tri-n butyl phosphate (TBP) from sulfate medium were investigated. It was found that the maximum extraction percent of vanadium occurs at pH 1.8 under ambient conditions; this phenomenon was ascribed to the predominant presence of cationic species of vanadium (VO2+) at this pH. Based on the Fourier Transform Infrared (FT-IR) spectrums, the POH bond of D2EHPA was found responsible for the extraction of VO2+ species through a cationic exchange mechanism. Employing the slope analysis method showed that the stoichiometric reaction... 

    Fourier transform infrared spectroscopy and scanning tunneling spectroscopy of porous silicon in the presence of methanol

    , Article Sensors and Actuators, B: Chemical ; Volume 132, Issue 1 , 2008 , Pages 40-44 ; 09254005 (ISSN) Razi, F ; Rahimi, F ; Iraji zad, A ; Sharif University of Technology
    2008
    Abstract
    Porous silicon samples were obtained from p+- and n-type silicon wafers. Gas sensing measurements showed that the electrical conductivity of porous Si on p+- and n-type wafers increases strongly and decreases weakly in the presence of methanol gas, respectively. Scanning tunneling spectroscopy (STS) indicates that the adsorption of methanol on the surface of n-porous silicon decreases the average density of states especially in the band gap. Fourier transform infrared (FTIR) spectroscopy reveals that after methanol exposure partial surface oxidation occurs which produces electron traps as well as methanol adsorption on the porous surfaces. These observations imply that the number of... 

    Enhanced inter-plane coupling of Mg doped Cu0.5Tl0.5Ba2Ca2- xMgxCu3O10-δ superconductors: XPS and FTIR studies

    , Article Physica C: Superconductivity and its Applications ; Volume 468, Issue 5 , 2008 , Pages 405-410 ; 09214534 (ISSN) Khurram, A. A ; Khan, N. A ; Ahadian, M. M ; Iraji zad, A ; Sharif University of Technology
    2008
    Abstract
    A comparison of X-ray photoemission spectroscopy of Mg doped Cu0.5Tl0.5Ba2Ca1.5Mg 0.5Cu3O10-δ and Mg free Cu0.5Tl0.5Ba2Ca2Cu 3O10-δ superconductor samples have been made. The main objective of these studies is to see the effect of Mg doping in developing better inter-plane coupling among the CuO2 planes and its effects on the chemical shift of the bonding species. Through these studies it is observed that thallium is in Tl+1 oxidation state in the Cu0.5Tl0.5Ba2O4- δ charge reservoir layer in both Mg doped and Mg free samples, however, the XPS line related to Ba atoms are shifted to higher binding energy side by 0.32 eV in Mg doped sample. This chemical shift is most likely due to presence of... 

    Adsorption of TiO2 nanoparticles on glass fibers

    , Article Journal of Physical Chemistry C ; Volume 111, Issue 27 , 2007 , Pages 9794-9798 ; 19327447 (ISSN) Khajeh Aminian, M ; Taghavinia, N ; Irajizad, A ; Mahdavi, M ; Sharif University of Technology
    2007
    Abstract
    Titania was deposited on glass fibers with a partial epoxy layer coating from a solution containing TiO2 nanoparticles at T = 90°C, and the adsorption process was examined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, and photocatalytic activity measurements. XPS data demonstrated that about 25% of the surface was covered with TiO2 nanoparticles, with 10% on the epoxy layer and 15% on the glass body. It was found that TiO2 nanoparticles can be readily adsorbed on epoxy groups, whereas they have a low tendency to adsorb on carbon polymer chains. This difference can be... 

    Two new swinging interferometers

    , Article Journal of Optics A: Pure and Applied Optics ; Volume 9, Issue 7 , 2007 , Pages 560-564 ; 14644258 (ISSN) Yazdi, S ; Rashidian, B ; Sharif University of Technology
    2007
    Abstract
    The most important disadvantage of swinging interferometers is that the optical path difference created in them is a nonlinear function of the rotation angle. In this paper, two new swinging interferometers are presented which have good linearity and provide a larger path difference in response to the rotation angle compared to other interferometers. This makes them suitable for applications such as high-resolution spectroscopy, and precision micro and nanopositioning. In one of these two interferometers, the optical path difference is created by rotation of a system composed of four mirrors, and in the other one it is created by rotation of a system consisting of two mirrors. They are not... 

    Synergistic effect of Cyanex 272 and Cyanex 302 on separation of cobalt and nickel by D2EHPA

    , Article Hydrometallurgy ; Volume 77, Issue 3-4 , 2005 , Pages 227-238 ; 0304386X (ISSN) Darvishi, D ; Haghshenas, D. F ; Keshavarz Alamdari, E ; Sadrnezhaad, S. K ; Halali, M ; Sharif University of Technology
    2005
    Abstract
    Synergistic effects of Cyanex 272 mixed with D2EHPA and Cyanex 302 mixed with D2EHPA were investigated for the separation of cobalt and nickel from a dilute sulfate media with the aim of reducing the reagent cost. Selective extraction of cobalt over nickel improved with respect to D2EHPA, but worsened with respect to Cyanex 272. By the application of the slope analysis method, the stoichiometric coefficient of the extractant was found to be four for cobalt and five for nickel, in a mixture of D2EHPA with Cyanex 302. However, it was four for both cobalt and nickel in a mixture of D2EHPA with Cyanex 272. Fourier Transform Infrared Spectroscopy (FT-IR) was utilized to examine the... 

    Partially aromatic polyamides based on tetraphenylthiophene diamine: synthesis and characterization

    , Article Journal of Applied Polymer Science, New York, NY, United States ; Volume 77, Issue 5 , 2000 , Pages 1144-1153 ; 00218995 (ISSN) Pourjavadi, A ; Zamanlu, M. R ; Zohuriaan Mehr, M. J ; Sharif University of Technology
    John Wiley & Sons Inc  2000
    Abstract
    Tetraphenylthiophene diamine (TPTDA) was prepared through a modified three-step route to achieve an improved overall yield. TPTDA reacted with succinic, adipic, suberic, sebasic, and fumaric acids via the Yamazaki phosphorylation method to yield novel partially aromatic polyamides (TPT series). A counterpart polyamide series based on p-phenylene diamine (Ph series) was also synthesized under the same conditions. All of the polymers were characterized by means of spectrochemical (Fourier transform infrared spectroscopy. 1H-nuclear magnetic resonance (NMR), and 13C-NMR) and thermal (differential scanning calorimetry and thermogravimetric) methods of analysis. Solubility of TPT polyamides was...