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Total 217 records
Surface Modification and Stabilization of TiO2 Nanoparticles for Sonodynamic Therapy
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor)
Abstract
Sonodynamic therapy has been developed over the last century, now it has become more widely used as a medical tool for the treatment of various diseases such as cancer. This technique involves delivery of sonosensitizing drugs, irradiation of ultrasound waves and motivation of drugs. In this thesis surface modification process with polymer and biocompatible surfactant on TiO2 nanoparticles has been done due to stabilization of TiO2 nanoparticles in neutral pH which is similar to inside-body situation. In the last step, for cancer therapy, doxorubicin as a cancer drug was loaded on TiO2 which was surface modified by PVA. The results revealed the best ratio of (PVA: TiO2), (SDS: TiO2), (SDS:...
On the Study and Comparison of the Post-yield Strain Softening in Polymer and Cellular Solid under Compression Loading
, Ph.D. Dissertation Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Strain softening after the yield point is a prevalent phenomenon in the stress-strain response of cellular solids, consisting of porosities in micro/macro-meter scale, as well as polymers, consisting of free volumes in sub-nanometer molecular scale. Although the underlying micromechanisms for softening in cellular solids are already known, the molecular origin for softening in polymers is still unknown. In this thesis, the micromechanisms of the softening in both materials are investigated. Then, a hypothesis is raised and evaluated to connect the nano-mechanics of softening in polymers to the micro-mechanics of softening in cellular solids. Experiments of compression test, positron-based...
Synthsis of Modified Graphene Nanocomposites Based on Biodegredable Polymers and Investigation of Their Mechanical، Electrochemical and Biological Properties
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor)
Abstract
Graphene، a molecular single layer of graphite، has tremendous applications in materials science for the development of nanocomposites، tissue engineering and supercapacitors. Graphene application and its developing applications depend on its essential properties such as excellent mechanical and thermal properties. Accordingly، investigation on graphene has drawn significant attention to itself. Hence، exploitation of these important properties including the induction of graphene sheets in polymer matrix seems to be essential. In the present survey، salep، a biodegradable polysaccharide، has been used for either the reduction of graphene oxide or functionalization of graphene. Then، reduced...
Synthesis of Core-Shell Nanoparticles Supported Iron and Vanadium Schiff Base and Their Application as a Catalyst for Oxidation of Sulfides, Alcohols and Olefins
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this work, synthesized Fe3O4 magnetic nanoparticles andcoated with SiO2 to prepare magnetic core-shell nanoparticles. Then immobilized Schiff baseof iron and vanadium complexes on magnetic core-shell nanoparticles was prepared as a recoverable magnetic nano catalysts. These catalysts were named Fe3O4@SiO2@L1@Fe, Fe3O4@SiO2@L2@Fe and Fe3O4@SiO2@L3@V. Furthermore,olefines epoxidation, sulfides and alcohols oxidation were studied with using iron and vanadium magnetic nano catalysts. The supported catalysts were characterized by atomic absorption, FT-IR and UV–Vis spectra.The catalytic performance of the synthesized iron catalyst was tested for the epoxidation of cyclohexene, styrene and...
Removal of Surface Defects and Improvement of Properties of Reverse Osmosis Membrane in Water Treatment Process
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
The purpose of this project is to correct the surface defects of the reverse osmosis membrane. The membrane tested in this project was a thin film made of three layers of polyester, polysulfone and polyamide. These three layers provide mechanical resistance to operating pressure, suitable substrate for polyamide layer synthesis and membrane selectivity, respectively.In order to improve the surface properties and modify the reverse osmosis membrane, it was first attempted to coat it with a protective layer of polyvinyl alcohol, then by modifying this layer and improving the properties of polyvinyl alcohol and synthesizing the sulfite agent on it by the esterification reaction, to the best...
Preparation of Cobalt and Manganese Salts of Para-amino Benzoic Acid Supported on Graphene Oxide as an Oxidative Nanocatalysts
, M.Sc. Thesis Sharif University of Technology ; Mahmoodi Hashemi, Mohammad (Supervisor)
Abstract
In this thesis, a heterogeneous nanocatalyst based on graphene oxide was synthesized. To improve the graphene oxide, it was reacted with paraaminobenzoic acid and then metal salts (cobalt and manganese) were coated on it. The structure of the catalyst was confirmed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), quantitative X-ray diffraction (EDS) and infrared (FT-IR) spectroscopy. Finally, the catalytic properties of the catalysts were evaluated in the oxidation reaction of different alcohols in the presence of oxygen. In the presence of benzyl alcohols with lethal electron groups, the oxidation conditions are stricter and the reaction efficiency is lower....
Estimation of Chitgar Lake Evaporation and the Impact of Chemical Coverings on its Reduction
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)
Abstract
Reducing water evaporation is one of the ways to overcome the low precipitation and drought conditions in water reservoirs. For this purpose, extensive studies have been investigated on physical and chemical coatings on lakes and reservoirs. Physical methods often involve the use of floating covers on the water surface to block evaporation by shading, most of which are only suitable for reservoirs with surface areas smaller than 5 hectares. In chemical methods, the evaporation can be decreased by nanomaterial coating, usually, containing long-chain molecules, which by spraying them on the surface, molecular monolayers are formed. In this study, the effect of nanometer coatings on the surface...
A Study of the Energetics of β-halogenated Alcohols Decomposition on Ni, Cu and Ni-Cu Alloys by the Method of UBI-QEP (Unity Bond Index-Quadratic Exponential Potential)
,
Ph.D. Dissertation
Sharif University of Technology
;
Gobal, Fereydoon
(Supervisor)
Abstract
In this work, Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) method was applied to investigate the decomposition routs of -halo alcohols on Ni(111) and Cu(111) crystallographic planes and Ni2Cu1(111) and Ni1Cu2(111) alloys. UBI-QEP calculates energetics, H and E, along reactions routes using heats of atomic adsorption as empirical inputs and in this way avoids needs to be very specific about every system. The results of analysis of -halo-propanols on Ni and Cu surfaces are in good agreement with experimental findings; namely in the formation of carbon-monoxide, ethylene, water and hydrogen over Ni and propene and water over Cu. Predicted activity of -halo-propanols,...
Synthesis and Characterization of Vanadium (IV)-SNO & ONO Tridentate Schiff-Base Complexes and Their Applications in Sulfide and Alcohol Oxidation in Ionic Liquid Media
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In recent years, application of transition metal biphasic catalytic systems for different reactions is an area of intense research activity. Among these reactions, oxidation of sulfides to sulfoxides and sulfones due to their importance as an intermediate in synthesis of organic compounds is a center of interest. Also, the catalytic conversion of alcohols to the corresponding aldehydes or ketones is a fundamental transformation in both laboratory and industrial synthetic chemistry. From environmental perspectives, the development of new catalytic oxidation systems with molecular oxygen as green oxidant is particularly attractive. In recent years, ionic liquids have been extensively studied...
Preparation of Gelatin/Pva Porous Scaffolds by Chemical and Gamma Irradiation Methods for Skin Cell Culture
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Dadbin, Susan (Supervisor)
Abstract
The goal of this research project was to prepare gelatin/PVA porous scaffolds by chemical and gamma irradiation methods to be used for human dermal fibroblast cell culture. First, the polymers were dissolved in hot water and mixed properly to achieve a homogenous solution. The mixture was then frozen at -200C and immersed in ethanol/ glutaraldehyde solution at -200C for 48 hours in order to extract ice crystals and also form chemical crosslinks in gelatin by glutaraldehyde. After being rinsed with distilled water the samples were lyophilized. The effects of polymers solution concentration, gelatin/PVA ratio and glutaraldehyde /gelatin ratio were investigated on characteristics of the...
Fabrication and Characterization of Thermoplastic Starch Based Nanocomposite for Bone Scaffold
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
This project aimed to fabricate the bone scaffolds with applying thermoplastic starch-based nano-biocomposites. The starting materials for this scaffold are as follows: thermoplastic starch, ethylene vinyl alcohol as the polymer matrix and nanoforsterite as the ceramic reinforcing phase. Furthermore, vitamin E was used as antioxidant for preserving starch against thermo-mechanical degradations. Likewise, 3D pore structure was developed using azo-dicarbonamide and water in injection moulding process. With blending thermoplastic starch and ethylene vinyl alcohol, some thermoplastic starch’s properties including degradation rate and water absorption were modified. In addition, having...
Synthesis, Characterization and Surface Modification of Iron Oxide Nanoparticles for Biomedical Applications
,
Ph.D. Dissertation
Sharif University of Technology
;
Simchi, Abdolreza
(Supervisor)
;
Imani, Mohammad
(Supervisor)
;
Bagheri, Reza
(Supervisor)
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) with proper surface coatings are increasingly being evaluated for clinical applications such as hyperthermia, drug delivery, magnetic resonance imaging, transfection, and cell/protein separation. Since the particles with various sizes exhibit different flow rates in the same environment (same capillary size), it is essential to use particles of a desirable size for targeted drug delivery and imaging. Particles of different sizes may be exposed to different viscosities and behave differently, particularly with regard to their velocities as they move through capillaries. In the present work, SPION with different size, purity, shape and...
Investigating the Effect of Chemical Coating on Reducing Evaporation from Saline Waters (Case Study of Lake Urmia)
, M.Sc. Thesis Sharif University of Technology ; Tajrishi, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)
Abstract
This study tries to introduce chemical coatings to reducing evaporation from Lake Urmia(LU). In LU, average annual evaporation is estimated at more than 1,000 mm, more than 80% of evaporation occurring in the warmer months of the year. Therefore, by reducing water evaporation, especially in the warmer months of the year, the most crucial factor in water outflow from LU can be reduced.At first, on the scale of class A evaporation pan in Tehran, three kinds of chemical coatings constituted stearic acid, jojoba oil, and fatty alcohols of style and stearyl to reduce evaporation from the LU is investigated. Then the best coating that includes combine of style and stearyl alcohols with stearic...
Synthesis and Catalytic Properties of Novel Manganese (III)-oxazine Complex in Oxidation of Sulfides and Alcohols
, M.Sc. Thesis Sharif University of Technology ; Bagherzadeh, Mojtaba (Supervisor)
Abstract
In this study new manganese(III) complexes of phox [Mn(phox)2(MeOH)2](ClO4), (phox= 2-(2` hydroxyphenyl)-5,6-dihydro-1,3-oxazine) have been synthesized and characterized with CHN,NMR and IR.The six-membered bidentate (N,O) oxazine ligand have been widely used throughout organometallic and inorganic chemistry, and are particularly important in homogeneous catalysis. The presence of N and O donor sites in oxazines may modify significantly the ligand roles for the variation of steric and electronic properties. Therefore, such systems are worth exploring for new catalytic uses . Catalytic oxidation reactions provide excellent alternatives for the use of stoichiometric reagents like urea...
Design of a Colorimetric Sensor Array Based on Aggregation of Gold Nanoparticles on the Surface of Probiotic Bacteria for Identification and Discrimination of Antiseptic Alcohols
, M.Sc. Thesis Sharif University of Technology ; Hormozinezhad, Mohammad Reza (Supervisor)
Abstract
The occurrence of the COVID-19 pandemic and the subsequent rising demand for purchasing alcohol-based sanitizers led to a remarkable prosperity in supplying these hygiene products. Hence, the development of a straightforward and efficient analytical strategy for discrimination of antiseptic alcohols including methanol, ethanol and isopropanol is of great importance. By exploiting the alcohol-sensitive membranes of probiotic bacteria, this research aims to develop a colorimetric sensor array for discriminating methanol, ethanol and isopropanol. In this design, the aggregation of citrate-capped gold nanoparticles (Au NPs) on the thiol-modified surface of two probiotic bacteria, including...
HAP/Agar Nanocarriers for Bone Anti-infection Drug
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masood (Supervisor)
Abstract
Successful treatment of bone infections is a major orthopedic challenge due to the physiological and anatomical features of bone. In this project, we prepared a drug delivery system with injectable and biodegradable polysaccharide agar containing alginate, polyvinyl alcohol and hydroxyapatite nanocarriers composite microspheres. Alginate and polyvinyl alcohol composite microspheres are crosslinked by calcium and freeze-thawing technique. Using the freeze thawing process for polyvinyl alcohol crosslinking, in addition to alginate crosslinking, improved hydrogel swelling behavior and enhanced drug loading and thus slowed drug release, drug loading increased with increasing PVA percentage from ...
Design and Synthesis of Heterogeneous Nano Catalyst Based on Immobilized Palladium Metal on Double Network Hydrogel and Its Application in Organic Reactions
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor)
Abstract
In the past few decades, many attempts have been made to combine the benefits of homogeneous and heterogeneous catalysts. The immobilization of homogeneous catalysts onto the surface of heterogeneous supports is the result of such efforts. In this research, immobilized heterogeneous catalysts were designed and synthesized based on double network hydrogels, which produce from interpenetrating of two biocompatible and biodegradable polymer networks. In order to provide magnetic responsibility and easy separation of catalyst from the reaction mixture, the magnetic nanoparticles were dispersed onto the surface of double network hydrogel. Finally, various metal nanoparticles such as palladium and...
Oxygen Barrier PLA Nanocomposite Films and Effect of Gamma Irradiation
, M.Sc. Thesis Sharif University of Technology ; Forounchi, Massoud (Supervisor) ; Dadbin, Susan (Supervisor)
Abstract
The present work investigates a novel approach for improving the oxygen-barrier property of PLA-based film using vinyl acetate-vinyl alcohol copolymer [Poly(VAc-co-VA)] and the nanoclay Nanolin DK4. The permeability, thermal and mechanical properties are studied. To synthesize poly(VAc-co-VA), the hydrolysis of PVAc was done. The nanocomposite blend of PLA/Poly(VAc-co-VA)/Nanolin DK4 was prepared by the solution casting method. The prepared nanocomposite films were optically transparent regardless of poly(Vac-co-VA) and Nanolin DK4 concentrations. The gamma irradiated Poly(VAc-co-VA) was incorporated in the PLA films to probe the effect of cross-linked copolymer on the permeability of the...
Synthesis of Dithiocarbamate Derivatives and Aminolysis of Epoxides in Water and under Different Conditions
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Reza (Supervisor) ; Ziyaei Halimehjani, Azim (Supervisor)
Abstract
This research project contains two parts that investigating new approaches for becoming closer to green chemistry principals is clear in it. In the first part we tried to synthesis dithiocarbamate salts using aromatic amins and than Michael addition of them to prepare bifunctional dithiocarbamats. But we found ?-thiols as final product. In the second part of this project, we investigated the regioselective epoxide ring opening with aromatic amines by using boric acid and glycerol in water as a green media. Corresponding ?-amino alcohols were obtained with excellent yields and considerable regioselectivity. High yields of the products, mild reaction conditions, using green catalyst and water...
Synthesis of Graphene-Based Magnetic Nanocatalyst Supported Ag Nanoparticles for Alcohols Oxidation
, M.Sc. Thesis Sharif University of Technology ; Mahmoodi Hashemi, Mohammad (Supervisor)
Abstract
In this thesis the graphene-based magnetic nanocatalyst was synthesized. The surface of this catalyst was cavered by silica and AgNPs. In addithion of simple sepration by magnetbar, yeild of reaction was promoted by surface modification. Catalyst structure was verified by transmission electron microscopy , scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and Energy dispersive spectroscopy.At the end catalytic activity was examined by oxidation reaction in persense of different alcohols. The oxidation of benzylic alcohol with electron withdrawing substituents was more difficult and the yield was lower, but electron donor substituents effect positively...