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Structural and Functional Models for the Molybdenum, Tungsten and Copper Enzymes: Synthesis, Properties and Reactivity
, Ph.D. Dissertation Sharif University of Technology ; Mohammadi Boghaei, Davar (Supervisor)
Abstract
In order to obtain more insight into the enzymatic oxygen-atom-transfer (OAT) process and elucidate the relation between the structure and function of the synthetic model complexes, new molybdenum and tungsten complexes containing different chelating ligands were systematically prepared and investigated. Herein, the cis-dioxo-molybdenum(VI) complexes with new aromatic dithiolene ligands, formulated as [MoO2(2,3ppdt)2]NR4 and [MoO2(3,4ppdt)2]NR4, (2,3ppdt= pyrido-2,3-pyrazine-2,3-dithiolato, 3,4ppdt= pyrido-3,4-pyrazine-2,3-dithiol and R= Et or Bu) were prepared and investigated by elemental analysis, IR, 1H NMR and UV-Vis spectroscopic methods. An OAT reaction of [MoO2(2,3ppdt)2]2– with PPh3...
Sensitive determination of dopamine in the presence of uric acid and ascorbic acid using TiO2 nanotubes modified with Pd, Pt and Au nanoparticles
, Article Analyst ; Volume 136, Issue 11 , 2011 , Pages 2322-2329 ; 00032654 (ISSN) ; Li, C ; Mahshid, S. S ; Askari, M ; Dolati, A ; Yang, L ; Luo, S ; Cai, Q ; Sharif University of Technology
2011
Abstract
A simple modified TiO2 nanotubes electrode was fabricated by electrodeposition of Pd, Pt and Au nanoparticles. The TiO2 nanotubes electrode was prepared using the anodizing method, followed by modifying Pd nanoparticles onto the tubes surface, offering a uniform conductive surface for electrodeposition of Pt and Au. The performance of the modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The Au/Pt/Pd/TiO2 NTs modified electrode represented a high sensitivity towards individual detection of dopamine as well as simultaneous detection of dopamine and uric acid using 0.1 M phosphate buffer solution (pH 7.00) as the base solution. In both case,...
Synthesis of Conductive Magnetite Nanocomposite based on Polyaniline/Poly(maleic acid-co-acrylic acid) with Core-Shell Structure
, Article Advances in Polymer Technology ; 2016 ; 07306679 (ISSN) ; Najafi Moghadam, P ; Mahmoodi Hashemi, M ; Sharif University of Technology
John Wiley and Sons Inc
2016
Abstract
In this study, a new type of magnetite nanocomposite with a core-shell structure was synthesized using Fe3O4 nanoparticles as a core and polyaniline (PANI) as a shell. For this propose, the surface of Fe3O4 was chemically modified with hexamethylenediisocyanate (HMDI) to improve its compatibility and interphase interaction with the polymeric matrix. Thereafter, the PANI was reacted with modified Fe3O4 to anchor them to PANI by covalent bands which acted as a shell. In the second step, the poly (maleic acid-co-acrylic acid) (P(MAc-co-AA)) as polymeric dopant for the PANI was synthesized. Finally, the PANI anchored to Fe3O4 was immersed in an aqueous solution of poly (maleic...
Simple and rapid detection of L-dopa based on in situ formation of polylevodopa nanoparticles
, Article Sensors and Actuators, B: Chemical ; Volume 243 , 2017 , Pages 715-720 ; 09254005 (ISSN) ; Moslehipour, A ; Bigdeli, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Levodopa [L-3, 4-dihydroxyphenylalanine, or L-DOPA] is an important neurotransmitter used for the treatment of neural disorders such as Parkinson's disease. Abnormal L-Dopa concentrations in biological fluids can be used for the evaluation of such diseases. In this work, a rapid and sensitive method for L-DOPA detection has been reported which is based on in situ formation of polylevodopa nanoparticles. Under alkaline conditions, L-DOPA is spontaneously oxidized to its quinone derivative and shows fluorescence properties. The fluorescence signal of the oxidation product has been monitored and used for the determination of L-DOPA in the presence of dopamine, uric acid, ascorbic acid and other...
DFT/B3LYP study of thermochemistry of D-glucosamine, a representative polyfunctional bioorganic compound
, Article Scientia Iranica ; Volume 15, Issue 4 , 2008 , Pages 422-429 ; 10263098 (ISSN) ; Ghorat, M ; Pourjavadi, A ; Kurdtabar, M ; Torabi, A. A ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
D-glucosamine, as a representative polyfunctional compound, is a bioactive amino sugar. In this study, the gas phase thermochemical properties of D-glucosamine, including its Metal Ion Affinity (MIA), metal binding sites, Anion Affinity (AA), acidity and proton affinity, have been explored, using the Density Functional Theory (DFT) and a 6-311++G**basis set. The summary of the MIA and AA results (in kcal/mol-1) are: Li+ = 67.6, Na+ = 51.1, K+ = 37.3, Mg2+ = 207.9, Ca2+ = 150.4, Zn2+ = 251.2, Cl- = 27.4, CN- = 28.0. The acidity values calculated at different sites, including four -OH groups and one -NH2 group, range from 344.0 to 373.0 kcal/mol-1. These results, surprisingly, indicate how...
Evaluation of anti-cancer and anti-metastatic effects of folate-PEGylated niosomes for co-delivery of letrozole and ascorbic acid on breast cancer cells
, Article Molecular Systems Design and Engineering ; Volume 7, Issue 9 , 2022 , Pages 1102-1118 ; 20589689 (ISSN) ; Khayam, N ; Noorbazargan, H ; Tavakkoli Yaraki, M ; Asghari Lalami, Z ; Akbarzadeh, I ; Eshrati Yeganeh, F ; Dolatabadi, A ; Mirzaei Rad, F ; Tan, Y. N ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Fighting with cancer requires the delivery of different therapeutics to the target cancerous cells by taking advantage of the synergistic effects of complementary medicine. Herein, we present a folate-PEGylated niosome as an efficient nanocarrier for targeted co-delivery of hydrophobic letrozole (L) and hydrophilic ascorbic acid (A) to breast cancer cells. The formulation of the niosomal nanocarrier was optimized by varying the ratio of cholesterol and surfactants to maximize the drug loading and minimize the size of nanocarriers. The optimum drug carriers were further functionalized with folate-PEG molecules to enhance the efficiency of drug delivery to the breast cancer cells and prevent...
Flash photo stimulation of human neural stem cells on graphene/TiO 2 heterojunction for differentiation into neurons
, Article Nanoscale ; Volume 5, Issue 21 , 2013 , Pages 10316-10326 ; 20403364 (ISSN) ; Ghaderi, E ; Sharif University of Technology
2013
Abstract
For the application of human neural stem cells (hNSCs) in neural regeneration and brain repair, it is necessary to stimulate hNSC differentiation towards neurons rather than glia. Due to the unique properties of graphene in stem cell differentiation, here we introduce reduced graphene oxide (rGO)/TiO2 heterojunction film as a biocompatible flash photo stimulator for effective differentiation of hNSCs into neurons. Using the stimulation, the number of cell nuclei on rGO/TiO2 increased by a factor of ∼1.5, while on GO/TiO2 and TiO2 it increased only ∼48 and 24%, respectively. Moreover, under optimum conditions of flash photo stimulation (10 mW cm-2 flash intensity and 15.0 mM ascorbic acid in...
Controlling aspect ratio of colloidal silver nanorods using response surface methodology
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 393 , 2012 , Pages 46-52 ; 09277757 (ISSN) ; Jalali Heravi, M ; Robatjazi, H ; Ebrahimi Najafabadi, H ; Sharif University of Technology
2012
Abstract
The properties of metallic nanorods vary due to changes in their composition, size and shape, which all depend on the aspect ratio of the nanorods. This work focuses on the optimization of the aspect ratio of silver nanorods using response surface methodology (RSM). Seed-mediated approach, which is the newest method with less difficulty, has been used for the synthesis of silver nanorods. First, silver ions were reduced with sodium borohydride in the presence of sodium citrate dehydrate, as stabilizer. Then, the prepared seeds were added to a solution containing more metal salts, a weak reducing agent (ascorbic acid) and a rod-like micellar template (cetyltrimethylammonium bromide, CTAB)....
Electrocatalytic determination of sumatriptan on the surface of carbon-paste electrode modified with a composite of cobalt/Schiff-base complex and carbon nanotube
, Article Bioelectrochemistry ; Volume 81, Issue 2 , 2011 , Pages 81-85 ; 15675394 (ISSN) ; Pakdel, Z ; Bezaatpour, A ; Shahrokhian, S ; Sharif University of Technology
2011
Abstract
The electrochemical oxidation of sumatriptan on the surface of carbon paste electrode modified with multi-walled carbon nanotube and cobalt methyl-salophen complex is studied by using cyclic voltammetry and polarization studies. The results indicate that the drug is irreversibly oxidized in a one electron oxidation mechanism. It was found that the peak potential shifted negatively with increasing pH, confirms that H + participate in the oxidation process. The electrode is shown to be very effective for the detection of sumatriptan in the presence of other biological reductant compounds. The prepared modified electrode exhibits a very good resolution between the voltammetric peaks of...
Evaluation of ascorbic acid-loaded calcium phosphate bone cements: Physical properties and in vitro release behavior
, Article Ceramics International ; Vol. 40, issue. 3 , April , 2014 , pp. 3961-3968 ; ISSN: 02728842 ; Hesaraki, S ; Nemati, A ; Sharif University of Technology
Abstract
In this study, different concentrations of ascorbic acid (50, 100 and 200 μg/mL) were added to the liquid phase of a calcium phosphate cement (CPC). The cements were immersed in simulated body fluid (SBF) for different intervals and physical, physicochemical and mechanical properties of them were evaluated. The release of added ascorbic acid from CPCs into the SBF solution was also studied. From the results, both setting time and injectability of CPC decreased by adding ascorbic acid, however the compressive strength was sharply increased before soaking in SBF solution. But, the compressive strength values of all cements (with or without ascorbic acid) soaked in SBF solution for more than 7...
Development of plasma and/or chemically induced graft co-polymerized electrospun poly(vinylidene fluoride) membranes for solute separation
, Article Separation and Purification Technology ; Volume 108 , 2013 , Pages 196-204 ; 13835866 (ISSN) ; Rana, D ; Matsuura, T ; Tabe, S ; Feng, C ; Sharif University of Technology
2013
Abstract
Nanofiber membranes were fabricated by electrospinning poly(vinylidene fluoride). The electrospun nanofiber membranes were further modified by grafting of acrylic acid (AA) and methacrylic acid (MAA) over the surfaces of the membranes. Plasma AA graft was attempted only, and the results indicated the partial membrane pore filling with grafted AA. For MAA grafting, chemically induced polymerization using benzoyl peroxide and hydrogen peroxide was attempted. The combination of plasma and chemically induced MAA graft polymerization was also attempted. The membranes were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA)...
Polysulfide poisoning of Ag electrocatalyst during L-ascorbate ion electro-oxidation in alkaline solution
, Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 33, Issue 2 , 2012 , Pages 267-274 ; 02539837 (ISSN) ; Majari Kasmaee, L ; Sharif University of Technology
Abstract
L-Ascorbate anion electro-oxidation on a silver electrode in hydroxide solution in the absence and presence of sodium polysulfide of concentrations from 1 × 10 -5 to 4.5 × 10 -4 mol/L was studied using cyclic voltammetry and electrochemical impedance spectroscopy. Both hydroxide and polysulfide ions inhibited L-ascorbate ion oxidation, with the poisoning effect of polysulfide ion being more pronounced in the potential range of -0.3 to -0.2 V/SCE. The time constants for L-ascorbate ion oxidation in the absence and presence of polysulfide were, 10 -3 to 1 × 10 -2 s and 1 × 10 -4 to 1 × 10 -2 s, respectively depending on the potential used for the impedance analysis. Based on the cyclic...
Catalytic activity of TiO 2 nanotubes modified with carbon and Pt nanoparticles for detection of dopamine
, Article ECS Transactions ; Volume 35, Issue 35 , 2011 , Pages 53-62 ; 19385862 (ISSN) ; 9781607682950 (ISBN) ; Mahshid, S. S ; Ghahremaninezhad, A ; Askari, M ; Dolati, A ; Yang, L ; Luo, Sh ; Cai, Q ; Sensor; Organic and Biological Electrochemistry ; Sharif University of Technology
2011
Abstract
Catalytic activity of carbon/Pt nanoparticles modified TiO 2 nanotubes electrode was studied by using dopamine contained solutions. The TiO 2 nanotubes electrode was prepared using anodizing method in aqueous solution. The electrochemical pulse method was then applied for electrodeposition of Pt nanoparticles onto the TiO 2 nanotubes. Further modification was achieved by decomposition of polyethylene glycol in a tube furnace to have a carbon/Pt nanoparticles modified TiO 2 nanotubes electrode. The final modified electrode could successfully detect the electro-oxidation of dopamine in a ImM contained solution using cyclic voltametry method. Also, a high sensitivity towards the oxidation of...
Template-based electrodeposition of Pt/Ni nanowires and its catalytic activity towards glucose oxidation
, Article Electrochimica Acta ; Volume 58, Issue 1 , 2011 , Pages 551-555 ; 00134686 (ISSN) ; Mahshid, S ; Dolati, A ; Ghorbani, M ; Yang, L ; Luo, S ; Cai, Q ; Sharif University of Technology
2011
Abstract
An electro-catalysis non-enzymatic electrode is proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and Ni within a nano-pore polycarbonate (PC) membrane followed by a chemical etching of the membrane. The electrode structure is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resulting Pt/Ni NWAs electrode shows high electrocatalytic activities towards the oxidation of glucose in alkaline solution. Consequently, a sensitive amperometric detection of glucose is achieved under 0.45 V vs. SCE with a low detection limit of 1.5 μM within a wide linear...
Super alcohol-absorbent gels of sulfonic acid-contained poly(acrylic acid)
, Article Journal of Polymer Research ; Volume 18, Issue 3 , 2011 , Pages 449-458 ; 10229760 (ISSN) ; Lashani, S ; Zohuriaan Mehr, M. J ; Kheirabadi, M ; Sharif University of Technology
2011
Abstract
Alcohol-specific superabsorbing gels (superalcogels) based on non-neutralized acrylic acid (AA, 60-94 mol%) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) were prepared via solution polymerization in water. Polyethylene glycol dimethacrylate and potassium persulfate were used as crosslinker and initiator, respectively. Characterization of samples was performed using FTIR, 1H-NMR and thermomechanical analyses. Glass transition temperature and modulus of dried samples were found to be directly changed with their AA content. The gels exhibited enormous ability for absorbing and retaining a variety of mono- and poly-hydric alcohols. For example, in lieu of one gram of a typical sample...
High-performance carboxylate superplasticizers for concretes: Interplay between the polymerization temperature and properties
, Article Journal of Applied Polymer Science ; Volume 134, Issue 23 , 2017 ; 00218995 (ISSN) ; Saeb, M. R ; Jafari, S. H ; Najafi, F ; Khonakdar, H. A ; Ayoubi, M ; Hassanpour Asl, F ; Sharif University of Technology
Abstract
Polycarboxylate superplasticizers based on acrylic acid (AA) and maleic anhydride (MAn) were synthesized via free-radical copolymerization with an ethylene glycol monomer and characterized. The copolymerization temperature (ranging from 50 to 90 °C) appeared to be the key operating factor governing the chemical structure of the superplasticizers. The chemical structures of the products were analyzed by gel permeation chromatography, whereas an optimized sample was further analyzed by Fourier transform infrared spectroscopy and 1H-NMR. Superplasticizers of the AA and MAn classes were then incorporated into concrete, and their performances were measured by slump and slump loss tests, where a...
Three-dimensional hybrid graphene/nickel electrodes on zinc oxide nanorod arrays as non-enzymatic glucose biosensors
, Article Sensors and Actuators, B: Chemical ; Volume 251 , 2017 , Pages 462-471 ; 09254005 (ISSN) ; Aashuri, H ; Simchi, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
We present a novel hybrid electrode based on reduced graphene oxide/nickel/zinc oxide heterostructures. The sensor was fabricated by template-free hydrothermal growth of ZnO nanorod arrays on conductive glass substrates (FTO) followed by conformal electrodeposition of nickel nanoparticles with an average size of 18 nm. Then, in-situ reduction and electrophoretic deposition of graphene oxide (GO) nanosheets on the structured ZnO/Ni electrode was performed. The prepared three-dimensional nanostructure exhibited fast electrocatalytic response (<3 s) towards glucose oxidation due to the large surface area and high electro-activity. The prepared biosensor possessed a wide linear range over...
Mechanochemical green synthesis of exfoliated edge-functionalized boron nitride quantum dots: application to vitamin c sensing through hybridization with gold electrodes
, Article ACS Applied Materials and Interfaces ; Volume 10, Issue 34 , 2018 , Pages 28819-28827 ; 19448244 (ISSN) ; Hatamie, A ; Ghanbari, H ; Simchi, A ; Sharif University of Technology
American Chemical Society
2018
Abstract
Two-dimensional boron nitride quantum dots (2D BNQDs) with excellent chemical stability, high photoluminescence efficiency, and low toxicity are a new class of advanced materials for biosensing and bioimaging applications. To overcome the current challenge about the lack of facile, scalable, and reproducible synthesis approach of BNQDs, we introduce a green and facile approach based on mechanochemical exfoliation of bulk h-BN particles in ethanol. Few-layered hydroxylated-functionalized QDs with a thickness of 1-2 nm and a lateral dimension of 2-6 nm have been prepared. The synthesized nanocrystals exhibit a strong fluorescence emission at 407 and 425 nm with a quantum efficiency of ∼6.2%....
Synthesis of conductive magnetite nanocomposite based on polyaniline/poly(maleic acid-co-acrylic acid) with core–shell structure
, Article Advances in Polymer Technology ; Volume 37, Issue 4 , 2018 , Pages 1041-1049 ; 07306679 (ISSN) ; Najafi moghadam, P ; Mahmoodi hashemi, M ; Sharif University of Technology
John Wiley and Sons Inc
2018
Abstract
In this study, a new type of magnetite nanocomposite with a core–shell structure was synthesized using Fe3O4 nanoparticles as a core and polyaniline (PANI) as a shell. For this propose, the surface of Fe3O4 was chemically modified with hexamethylenediisocyanate (HMDI) to improve its compatibility and interphase interaction with the polymeric matrix. Thereafter, the PANI was reacted with modified Fe3O4 to anchor them to PANI by covalent bands which acted as a shell. In the second step, the poly (maleic acid-co-acrylic acid) (P(MAc-co-AA)) as polymeric dopant for the PANI was synthesized. Finally, the PANI anchored to Fe3O4 was immersed in an aqueous solution of poly (maleic...
Modification of carbon paste with congo red supported on multi-walled carbon nanotube for voltammetric determination of uric acid in the presence of ascorbic acid
, Article Journal of Solid State Electrochemistry ; Volume 13, Issue 10 , 2009 , Pages 1567-1575 ; 14328488 (ISSN) ; Zare Mehrjardi, H. R ; Khajehsharifi, H ; Sharif University of Technology
2009
Abstract
A chemically modified carbon-paste electrode (CPE) is prepared by incorporating congo red (CR) immobilized on multi-walled carbon nanotube (MWCNT). The results show that CR is effectively immobilized on the surface of MWCNT under the ultrasonic agitation in aqueous solution and further incorporating the nafion. The prepared electrode, due to the electrostatic repulsions between the CR and ascorbate anion, is capable to mask the response of the ascorbic acid (AA) completely and provide an effective method for the detection of minor amounts of uric acid (UA) in the presence of high concentrations of AA. On the other hand, an increase in the microscopic area of the electrode by addition of...