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    2,6-Bis(diphenylphosphino)pyridine: A simple ligand showing high performance in palladium-catalyzed CN coupling reactions

    , Article Tetrahedron Letters ; Vol. 55, issue. 30 , July , 2014 , p. 4098-4101 ; ISSN: 00404039 Nadri, S ; Rafiee, E ; Jamali, S ; Joshaghani, M ; Sharif University of Technology
    Abstract
    The use of commercially available 2,6-bis(diphenylphosphino)pyridine as a ligand in conjunction with K2CO3, DMAc and TBAB is an effective method for the palladium-catalyzed CN coupling of a variety of aryl halides with anilines, N-heterocyclic aromatic amines, and a cyclic secondary amine. The reactions proceed in good to excellent yield (up to 98%) while the loading of Pd(OAc)2 was as low as 0.025 mol %  

    Carbon nanotubes part I: Preparation of a novel and versatile drug-delivery vehicle

    , Article Expert Opinion on Drug Delivery ; Volume 12, Issue 7 , 2015 , Pages 1071-1087 ; 17425247 (ISSN) Karimi, M ; Solati, N ; Amiri, M ; Mirshekari, H ; Mohamed, E ; Taheri, M ; Hashemkhani, M ; Saeidi, A ; Estiar, M. A ; Kiani, P ; Ghasemi, A ; Basri, S. M. M ; Aref, A. R ; Hamblin, M. R ; Sharif University of Technology
    Informa Healthcare  2015
    Abstract
    Introduction: It is 23 years since carbon allotrope known as carbon nanotubes (CNT) was discovered by Iijima, who described them as "rolled graphite sheets inserted into each other". Since then, CNTs have been studied in nanoelectronic devices. However, CNTs also possess the versatility to act as drug- and gene-delivery vehicles.Areas covered: This review covers the synthesis, purification and functionalization of CNTs. Arc discharge, laser ablation and chemical vapor deposition are the principle synthesis methods. Non-covalent functionalization relies on attachment of biomolecules by coating the CNT with surfactants, synthetic polymers and biopolymers. Covalent functionalization often... 

    Polyethylene glycol (PEG) as a green solvent for carbon-carbon bond formation reactions

    , Article Journal of Molecular Liquids ; Volume 207 , 2015 , Pages 73-79 ; 01677322 (ISSN) Vafaeezadeh, M ; Mahmoodi Hashemi, M ; Sharif University of Technology
    Abstract
    In recent years, polyethylene glycol (PEG) has attracted special attention as a green and inexpensive solvent in various chemical transformations. The current critical review deals with breakthrough achievements for the applications of PEG as an alternative reaction media well-known coupling reactions such as Suzuki, Heck, Stille, Sonogashira, Hiyama and some challenging organic reactions for carbon-carbon bond formation  

    Bonding, structural and thermodynamic analysis of dissociative adsorption of H3O+ ion onto calcite (10 1 ¯ 4) surface: CPMD and DFT calculations

    , Article Journal of Molecular Modeling ; Volume 23, Issue 12 , 2017 ; 16102940 (ISSN) Ghatee, M. H ; Koleini, M. M ; Sharif University of Technology
    Abstract
    We used density functional theory (DFT) and Car-Parrinello molecular dynamics (CPMD) simulation to investigate the adsorption and bond formation of hydronium ion (H3O+) onto a (10 1 ¯ 4) calcite surface. For surface coverage of 25% to 100%, the nature of H3O+ interaction was explored through electron density and energetics in the context of bond critical points. The adsorbate–adsorbent structure was studied by simulation of pair correlation function. The results revealed that dissociation into water molecule(s) and proton(s) complements H3O+ ion(s) adsorbtion. The H2O molecule adsorbs onto the surface via its O atom, and interacts with surface calcium in a closed-shell mode; the H+ ion makes... 

    Regioselective diversification of 2,1-borazaronaphthalenes: unlocking isosteric space via C-H activation

    , Article Journal of Organic Chemistry ; Volume 82, Issue 15 , 2017 , Pages 8072-8084 ; 00223263 (ISSN) Davies, G. H. M ; Jouffroy, M ; Sherafat, F ; Saeednia, B ; Howshall, C ; Molander, G. A ; Sharif University of Technology
    Abstract
    Methods for the regioselective C-H borylation and subsequent cross-coupling of the 2,1-borazaronaphthalene core are reported. Azaborines are dependent on B-N/C=C isosterism when employed in strategies for developing diverse heterocyclic scaffolds. Although 2,1-borazaronaphthalene is closely related to naphthalene in terms of structure, the argument is made that the former has electronic similarities to indole. Based on that premise, iridium-mediated C-H activation has enabled facile installation of a versatile, nucleophilic coupling handle at a previously inaccessible site of 2,1-borazaronaphthalenes. A variety of substituted 2,1-borazaronaphthalene cores can be successfully borylated and... 

    Dual-sensitive hydrogel nanoparticles based on conjugated thermoresponsive copolymers and protein filaments for triggerable drug delivery

    , Article ACS Applied Materials and Interfaces ; Volume 10, Issue 23 , 17 May , 2018 , Pages 19336-19346 ; 19448244 (ISSN) Ghaffari, R ; Eslahi, N ; Tamjid, E ; Simchi, A ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    In this study, novel hydrogel nanoparticles with dual triggerable release properties based on fibrous structural proteins (keratin) and thermoresponsive copolymers (Pluronic) are introduced. Nanoparticles were used for curcumin delivery as effective and safe anticancer agents, the hydrophobicity of which has limited their clinical applications. A drug was loaded into hydrogel nanoparticles by a single-step nanoprecipitation method. The drug-loaded nanoparticles had an average diameter of 165 and 66 nm at 25 and 37 °C, respectively. It was shown that the drug loading efficiency could be enhanced through crosslinking of the disulfide bonds in keratin. Crosslinking provided a targeted release... 

    New pathways of stability for NHCs derived from azole, di-azole, n-tetrazole, and ab-tetrazole, by DFT

    , Article Journal of Molecular Modeling ; Volume 26, Issue 11 , 2020 Ahmadi, A ; Kassaee, M. Z ; Ayoubi Chianeh, M ; Fattahi, A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2020
    Abstract
    We have investigated the pathways of stability for NHCs derived from azole, di-azole, n-tetrazole, and ab-tetrazole (1a, 2a, 3a, and 4a, respectively), at the M06/6-311++G** level of theory. Optimization and vibrational frequency calculations of ground states (GS) and transition states (TS) are performed to identify Gibbs free energies and nature of stationary points, respectively. Two possible pathways of stability for 1a-4a are compared and contrasted which entail dimerization through hydrogen bonding (HB) and covalent bonding (CB). The CB pathway comprises head to head (HH) and head to tail (HT) dimerizations. Plausible reaction profiles are illustrated for 1a-4a along with the mechanism... 

    Graphene oxide functionalized with oxygen-rich polymers as a pH-sensitive carrier for co-delivery of hydrophobic and hydrophilic drugs

    , Article Journal of Drug Delivery Science and Technology ; Volume 56 , 2020 Pourjavadi, A ; Asgari, S ; Hosseini, S. H ; Sharif University of Technology
    Editions de Sante  2020
    Abstract
    In this work, a novel carrier based-on modified graphene oxide was designed for co-delivery of hydrophobic and hydrophilic anticancer drugs (curcumin (Cur) and doxorubicin (DOX) as the model of drugs). The hydroxyl groups at the edges of graphene oxide (GO) sheets were used as the initiation sites for growing poly(epichlorohydrin) (PCH) chains. Then, hyperbranched polyglycerol (HPG) was grafted on the hydroxyl end groups of PCH (PCH-g-HPG). Pendant chlorines in the main chain of GO-PCH-g-HPG were replaced with hydrazine. The modification of GO sheets with oxygen-rich polymers increased water solubility of graphene oxide. Doxorubicin was loaded onto the nanocarrier by covalent bonding with... 

    Magnetic pH-responsive nanocarrier with long spacer length and high colloidal stability for controlled delivery of doxorubicin

    , Article Colloids and Surfaces B: Biointerfaces ; Vol. 116 , April , 2014 , pp. 49-54 ; ISSN: 09277765 Pourjavadi, A ; Hosseini, S. H ; Alizadeh, M ; Bennett, C ; Sharif University of Technology
    Abstract
    A novel magnetic nanocarrier with long spacer length and high colloidal stability has been prepared for effective delivery of doxorubicin (DOX). First, poly(amidoamine) (PAMAM) dendrimer was grown up onto the surface of superparamagnetic iron oxide nanoparticles to increase the loading amount of amine groups. Then, terminal amine groups were functionalized by polyethylene glycol dimethylester to increase the spacer length. Then anticancer drug DOX was covalently attached onto the system by hydrazone bond to forms a pH-sensitive nanocarrier. This system is designed to combine the advantage of magnetic targeting, high drug loading capacity, and controlled release  

    Silane functionalization of nanodiamond for polymer nanocomposites-effect of degree of silanization

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 506 , 2016 , Pages 254-263 ; 09277757 (ISSN) Hajiali, F ; Shojaei, A ; Sharif University of Technology
    Elsevier B.V  2016
    Abstract
    The silanization of nanodiamond (ND) was successfully carried out by using the esterification reaction of hydrolyzed vinyltrimethoxysilane (VTS) in alcoholic solution. The surface carboxylic group of ND was first enhanced by thermal oxidation to increase the degree of esterification reaction. The extent of silane functionalization of ND was controlled by varying the weight ratio of VTS and oxidized ND (oxND), from 2:1 to 10:1 (w/w) in the functionalization reaction medium. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) revealed that the highest degree of silanization occurred at VTS/oxND of 5:1 (w/w), while more silane concentrations resulted in... 

    Optimization of alginate-whey protein isolate microcapsules for survivability and release behavior of probiotic bacteria

    , Article Applied Biochemistry and Biotechnology ; Volume 190, Issue 1 , 2020 , Pages 182-196 Sajadi Dehkordi, S ; Alemzadeh, I ; Vaziri, A. S ; Vossoughi, A ; Sharif University of Technology
    Springer  2020
    Abstract
    The present study aimed to improve the survivability of L. acidophilus encapsulated in alginate-whey protein isolate (AL-WPI) biocomposite under simulated gastric juice (SGJ) and simulated intestinal juice (SIJ). Microcapsules were prepared based on emulsification/internal gelation technique. Optimal compositions of AL and WPI and their ratio in the aqueous phase were evaluated based on minimizing mean diameter (MD) of the microcapsules and maximizing encapsulation efficiency (EE), survivability of cells under SGJ (Viability), and release of viable cells under SIJ (Release) using Box-Behnken experimental design. Optimal composition comprising 4.54% (w/v) AL, 10% (w/v) WPI, and 10% (v/v)... 

    Amyloid fibril reduction through covalently modified lysine in HEWL and insulin

    , Article Archives of Biochemistry and Biophysics ; Volume 727 , 2022 ; 00039861 (ISSN) Rezaei, M ; Kalhor, H. R ; Sharif University of Technology
    Academic Press Inc  2022
    Abstract
    Proteins possess a variety of nucleophiles, which can carry out different reactions in the functioning cells. Proteins endogenously and synthetically can be modified through their nucleophilic sites. The roles of these chemical modifications have not been completely revealed. These modifications can alter the protein folding process. Protein folding directly affects the function of proteins. If an error in protein folding occurs, it may cause protein malfunction leading to several neurodegenerative disorders such as Alzheimer's and Parkinson's. In this study, Hen Egg White Lysozyme (HEWL) and bovine insulin, as model proteins for studying the amyloid formation, were covalently attached with... 

    Grafting the sol-gel based sorbents by diazonium salts: A novel approach toward unbreakable capillary microextraction

    , Article Journal of Chromatography A ; Volume 1318 , November , 2013 , Pages 58-64 ; 00219673 (ISSN) Bagheri, H ; Bayat, P ; Piri Moghadam, H ; Sharif University of Technology
    2013
    Abstract
    The present work deals with a novel approach for grafting a sol-gel based sorbent, using diazonium salts for preparation of an unbreakable capillary microextraction (CME) device in on-line combination with high performance liquid chromatography (HPLC). The use of diazonium salts modifier allowed all types of metallic and non-metallic substrates to be used without any limitation. Substrates including copper, brass, stainless steel and polytetrafluoroethylene (PTFE) were chosen to be functionalized by chemical or electrochemical reduction of 4-amino phenyl acetic acid. Then, 3-(trimethoxysilyl)propylamine (3TMSPA) was selected as the precursor and the only reagent for preparation of the... 

    Pharmaceuticals removal by immobilized laccase on polyvinylidene fluoride nanocomposite with multi-walled carbon nanotubes

    , Article Chemosphere ; Volume 263 , 2021 ; 00456535 (ISSN) Masjoudi, M ; Golgoli, M ; Ghobadi Nejad, Z ; Sadeghzadeh, S ; Borghei, S. M ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also... 

    Gold nanorods for drug and gene delivery: An overview of recent advancements

    , Article Pharmaceutics ; Volume 14, Issue 3 , 2022 ; 19994923 (ISSN) Jahangiri Manesh, A ; Mousazadeh, M ; Taji, S ; Bahmani, A ; Zarepour, A ; Zarrabi, A ; Sharifi, E ; Azimzadeh, M ; Sharif University of Technology
    MDPI  2022
    Abstract
    Over the past few decades, gold nanomaterials have shown great promise in the field of nanotechnology, especially in medical and biological applications. They have become the most used nanomaterials in those fields due to their several advantageous. However, rod-shaped gold nanoparticles, or gold nanorods (GNRs), have some more unique physical, optical, and chemical properties, making them proper candidates for biomedical applications including drug/gene delivery, photothermal/photodynamic therapy, and theranostics. Most of their therapeutic applications are based on their ability for tunable heat generation upon exposure to near-infrared (NIR) radiation, which is helpful in both... 

    Size-dependent genotoxicity of graphene nanoplatelets in human stem cells

    , Article Biomaterials ; Volume 33, Issue 32 , 2012 , Pages 8017-8025 ; 01429612 (ISSN) Akhavan, O ; Ghaderi, E ; Akhavan, A ; Sharif University of Technology
    2012
    Abstract
    Reduced graphene oxide nanoplatelets (rGONPs) were synthesized by sonication of covalently PEGylated GO sheets followed by a chemical reduction using hydrazine and bovine serum albumin. Human mesenchymal stem cells (hMSCs), as a fundamental factor in tissue engineering, were isolated from umbilical cord blood (as a recently proposed source for extracting fresh hMSCs) to investigate, for the first time, the size-dependent cyto- and geno-toxic effects of the rGONPs on the cells. The cell viability test showed significant cell destructions by 1.0 μg/mL rGONPs with average lateral dimensions (ALDs) of 11±4 nm, while the rGO sheets with ALDs of 3.8±0.4 μm could exhibit a significant cytotoxic... 

    Mediator-less highly sensitive voltammetric detection of glutamate using glutamate dehydrogenase/vertically aligned CNTs grown on silicon substrate

    , Article Biosensors and Bioelectronics ; Volume 31, Issue 1 , 2012 , Pages 110-115 ; 09565663 (ISSN) Gholizadeh, A ; Shahrokhian, S ; Iraji zad, A ; Mohajerzadeh, S ; Vosoughi, M ; Darbari, S ; Sanaee, Z ; Sharif University of Technology
    Abstract
    A sensitive glutamate biosensor is prepared based on glutamate dehydrogenase/vertically aligned carbon nanotubes (GLDH, VACNTs). Vertically aligned carbon nanotubes were grown on a silicon substrate by direct current plasma enhanced chemical vapor deposition (DC-PECVD) method. The electrochemical behavior of the synthesized VACNTs was investigated by cyclic voltammetry and electrochemical impedance spectroscopic methods. Glutamate dehydrogenase covalently attached on tip of VACNTs. The electrochemical performance of the electrode for detection of glutamate was investigated by cyclic and differential pulse voltammetry. Differential pulse voltammetric determinations of glutamate are performed...