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The Impact of Negative/Positive Emotions on English Language Teachers` Identity: A Mixed-Method Research
, M.Sc. Thesis Sharif University of Technology ; Rezaei, Saeed (Supervisor)
Abstract
This study was a mixed-method research into the impact of emotions on the professional identities of teachers. The researcher followed Zembylas (2005a, 2005b) in conducting this study following the argument that politics and disciplinary power affect every aspect of teachers` life, hence their emotions and professional identities. Foucault (1975, 1984) was the source of theoretical underpinning in this study. The researcher used an open written interview, an attitudinal questionnaire, and a written narrative inquiry to collect the required data. Ten English language teachers (8 English Institute teachers, 2 public school teachers) took part in the first phase. One-hundred teachers from both...
Design and Optimization of Digital Microfluidic Chip for Cell Sorting
, M.Sc. Thesis Sharif University of Technology ; Fardmanesh, Mehdi (Supervisor)
Abstract
Today, microfluidics, representing the precise and controlled displacement of small amounts of fluid, is one of the most efficient tools available in various research fields, including medicine. Digital microfluidics is one of the newest microfluidic methods, which is based on the theory of electrowetting on dielectric. According to this theory, by applying a voltage difference to a droplet of fluid on a hydrophobic surface, the droplet can be moved on that surface. Therefore, by fabricating a plate containing a number of electrodes completely isolated from each other and controlling them, small droplets of fluid can be moved on a hydrophobic surface. In this thesis, the electrodes of this...
Additive Manufacturing of Structured Stainless Steel Electrodes Functionalized with Transition Metal-Oorganic Frameworks for Water Splitting
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdolreza (Supervisor)
Abstract
Water splitting reaction always faces challenges such as low efficiency, slow kinetics, and long-term instability of the catalyst. In this study, an electrode made of low-carbon 316 stainless steel fabricated by selective laser melting was initially used as the catalyst. The overpotential for hydrogen evolution reaction at a current density of 10 mA cm-2 using this electrode was calculated to be -0.505 V vs. RHE. This electrode had the capability of producing hydrogen gas at a rate of 3.6 mL min-1. Then, to reduce the overpotential, improve the efficiency, and stability of this electrode, its surface was modified by electrochemical methods, and metal-organic framework with cores of iron,...
Two-dimensional quantum simulation of scaling effects in ultrathin body MOSFET structure: NEGF approach
, Article 14th International Workshop on the Physics of Semiconductor Devices, IWPSD, Mumbai, 16 December 2007 through 20 December 2007 ; 2007 , Pages 240-242 ; 9781424417285 (ISBN) ; Dehdashti, N ; Faez, R ; Sharif University of Technology
2007
Abstract
For the first time, we present self-consistent solution of ultrathin body device structures to investigate the device parameters variation on the characteristics of nanoscale MOSFET. Our two dimensional (2-D) device simulator Is based on Nonequlibrium Green's Function (NEGF) forma lism. Starting from a basic structure (DG-MOSFET) with a gate length of 10 nm, variation of gate length, channel thickness, gate oxide parameters was carried out in connection with the numerical calculation of device characteristics. In this work Quantum transport equations are solved in 2-D by NEGF method in active area of the device to obtain the charge density and Poisson's equation is solved in entire domain of...
Machine Learning-Assisted Colorimetric Assay Based on Au@Ag Nanorods for Chromium Speciation
, Article Analytical Chemistry ; Volume 95, Issue 26 , 2023 , Pages 10110-10118 ; 00032700 (ISSN) ; Ghasemi, F ; Hormozinezhad, M. R ; Sharif University of Technology
American Chemical Society
2023
Abstract
The oxidation state of an element significantly controls its toxicological impacts on biological ecosystems. Therefore, design of robust sensing strategies for multiplex detection of species with respect to their oxidation states or bonding conditions, i.e., chemical speciation, is quite consequential. Chromium (Cr) species are known as the most abundant inorganic groundwater pollutants and can be quite harmful to human health depending on their oxidation states. In the present study, a multicolorimetric probe based on silver-deposition-induced color variations of gold nanorods (AuNRs) was designed for identification and quantification of Cr species including Cr (III) and Cr (VI) (i.e.,...
Design of Colorimetric Sensor Array for Simultanous Detection of Phosalone and Azinphosmethyl Pesticides Based on Aggregation Silver Nanoparticles (AgNPs)
, M.Sc. Thesis Sharif University of Technology ; Hormozinezhad, Mohammad Reza (Supervisor)
Abstract
Development of simple and rapid approaches for identification of pesticides has been known as a critical demand, due to the broad usage of pesticides and their harmful effects on mammals. Herein, we have introduced a silver nanoparticle (AgNP) based colorimetric sensor array for simultaneous identification of Azinphosmethyl (AM) and Phosalone (PS). In the presence of the target pesticides, unmodified AgNPs at various pHs (4.5, 5.5 and 9.5) showed different aggregation behaviours. As a result of aggregation, the color and UV-Vis spectra of AgNPs changed which led to distinct patterns for AM and PS. The aggregation induced spectral changes of AgNPs were used to identify AM and PS with the help...
, M.Sc. Thesis Sharif University of Technology ; Yaghmaei, Soheyla (Supervisor) ; Maghsoudi, Vida (Supervisor)
Abstract
This practice investigates about the resistance & sustainability of a sample of available microorganisms in fruit juices vs. a natural anti microbe called vanillin. To be more precisely the anti bacterial characteristic of vanillin has been tested against famous pathogenic organism Escherichia Coli in apple juice. The practice has been experienced for different concentrations of Vanillin, controlling & reducing the microbe concentration in apple synthetic juice. The effect has been investigated by measuring sensitivity of results in two different temperatures one in 8 degree of centigrade & other in 15, in each temperature two PH have been tested (PH = 3.5 & 4.5) 0-40-80 m-molar as 3...
Antimicrobial Effects of Iranian Red Sumac
, M.Sc. Thesis Sharif University of Technology ; Maghsoodi, Vida (Supervisor) ; Yaghmaei, Soheila (Supervisor)
Abstract
The most important desire of all researchers in food industry is decreasing the contamination of foods and increasing their shelf life. Due to harmfulness of chemical preservatives their use has been limited and therefore natural antimicrobials have been demanded. Recently spices have been noticed as natural antimicrobial agents. Sumac is a kind of spice which has antibacterial and antioxidant activities.The aim of this project is to investigate effects of water and alcoholic extracts of Iranian red sumac comparatively on three gram positive bacteria (Bacillus coagulans , Bacillus subtilis, Staphylococcus aureus) and one gram negative (Escherichia coli) by well and disk diffusion method....
Preparation of Gelatin-Alginate Hydrogel for Using as Cell Culture Scaffold
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohreh (Supervisor) ; Maghsoudi, Vida (Supervisor)
Abstract
Hydrogels are polymeric three-dimensional networks able to swell in the presence of an aqueous medium. Hydrogels from natural proteins and polysaccharides are ideal scaffolds for tissue engineering since they resemble the extracellular matrices of tissue comprised of various amino acids and sugar-based macromolecules.The biocompatible and biodegradable hydrogel scaffolds are promising materials for tissue engineering. Here, we report a new class of hydrogels derived from oxidized alginate (OA) and gelatin. The prepared oxidized alginate was shown to be efficient in crosslinking gelatin, leading to hydrogel formation. The effect of degree of oxidation and concentration of OA on the mechanical...
Investigating the Optimum Conditions for Cell Growth and Behavior on Hydrogel Surfaces
, M.Sc. Thesis Sharif University of Technology ; Mashayekhan, Shohre (Supervisor) ; Maghsudi, Vida (Supervisor)
Abstract
Generally, the concept of producing ‘spare parts’ of the body for replacement of damaged or lost organs lies at the core of the varied biotechnological practices referred as tissue engineering. Tissue engineering is an interdisciplinary field that incorporates principles of engineering with the life sciences. Tissue engineering is based on three principle; cells, scaffolds for cells expansion, attachment as an environment like ECM and growth factors. These things together can help tissue engineers to provide microenvironments which are suitable for special cells. The most important thing in this kind of works is the ability to simulate environment for cells the same as body. According to the...
Antioxidant Production from Rice Bran and Optimization of the Process
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Maghsoudi, Vida (Supervisor)
Abstract
An antioxidant is a molecule capable of preventing the oxidation of other molecules and neutralizing free radicals. Free radicals are the root cause for many human diseases.Rice bran is one of the most important co-products in the rice milling.In this research antioxidant activity of two Iranian rice bran varieties Fajr and Tarem, extracted by three different solvents (methanol, ethanol and ethyl acetate),determined at different time of extraction by measurement of total phenolic content, free radical scavenging, inhabitation of linoleic acid peroxidation and reducing power. The methanolic extract of Fajr rice bran produced strong results in antioxidant activity. The amount of Total...
Corrigendum to “ththnated development of a pH assisted AgNP-based colorimetric sensor array for simultaneous identification of phosalone and azinphosmethyl pesticides” [spectrochim. acta a mol. biomol. spectrosc. 219 (2019) 496–503](S138614251930455X)(10.1016/j.saa.2019.04.074)
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 223 , 2019 ; 13861425 (ISSN) ; Abbasi Moayed, S ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The authors regret “There are some meaningless letters at the beginning of the article's title. The authors would like to inform that the correct title is “Development of a pH assisted AgNP-based colorimetric sensor Array for simultaneous identification of phosalone and azinphosmethyl pesticides.” The authors would like to apologise for any inconvenience caused. © 2019 Elsevier B.V
ThThnated Development of a pH assisted AgNP-based colorimetric sensor Array for simultaneous identification of phosalone and azinphosmethyl pesticides
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 219 , 2019 , Pages 496-503 ; 13861425 (ISSN) ; Abbasi Moayed, S ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Development of simple and rapid methods for identification of pesticides, due to their broad usage and harmful effects on mammals, has been known as a critical demand. Herein, we have introduced a silver nanoparticle (AgNP)based colorimetric sensor array for simultaneous identification of Azinphosmethyl (AM)and Phosalone (PS)pesticides. In the presence of the target pesticides, unmodified AgNPs at various pHs (4.5, 5.5 and 9.5)showed different aggregation behaviors. As a result of aggregation, the color and UV–Vis spectra of AgNPs changed differentially, leading to distinct response patterns for AM and PS. The aggregation induced spectral changes of AgNPs, were used to identify AM and PS...
Providing Multicolor Plasmonic Patterns with Au@Ag Core-Shell Nanostructures for Visual Discrimination of Biogenic Amines
, Article ACS Applied Materials and Interfaces ; Volume 13, Issue 17 , 2021 , Pages 20865-20874 ; 19448244 (ISSN) ; Ghasemi, F ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
American Chemical Society
2021
Abstract
Biogenic amines (BAs) are known as substantial indicators of the quality and safety of food. Developing rapid and visual detection methods capable of simultaneously monitoring BAs is highly desired due to their harmful effects on human health. In the present study, we have designed a multicolor sensor array consisting of two types of gold nanostructures (i.e., gold nanorods (AuNRs) and gold nanospheres (AuNSs)) for the discrimination and determination of critical BAs (i.e., spermine (SM), tryptamine (TT), ethylenediamine (EA), tyramine (TR), spermidine (SD), and histamine (HT)). The design principle of the probe was based on the metallization of silver ions on the surface of AuNRs and AuNSs...
, M.Sc. Thesis Sharif University of Technology ; Aalemzadeh, Iran (Supervisor) ; Maghsoudi, Vida (Co-Advisor)
Abstract
Xanthan gum is a water-soluble exo-polysaccharide. It is produced industrially from carbon sources by fermentation using the gram-negative bacterium Xanthomonas campestris. There have been various attempts to produce xanthan gum by fermentation method using bacteria and yeast by using various cheap raw materials. In this study the cultural conditions for xanthan gum production by Xanthomonas campestris were investigated and optimized by response surface methodology, to maximize cell and xanthan production in batch experiments using YM broth without pH control. The individual and interactive effects of three independent variables (carbon source concentration (40-80 g/l), nitrogen source...
Investigation of Antioxidant & Antimicrobial Characteristics of Plums
, M.Sc. Thesis Sharif University of Technology ; Maghsoody, Vida (Supervisor) ; Razavi, Jalil (Supervisor)
Abstract
Food rich in antioxidants plays an essential role in the prevention of diseases and plum is an example of these food .Our objective in this research was to determine the amount of variation in total phenolic compound present in plum fruits, so that it can be utilized in breeding programs to enhance the health benefits.Total phenolic content of the fruits, which were determined in 7 genotypes by using 4 solvents (water , methanol , ethanol , acetone) to extract phenolic compound, ranged from 178 to 497 mg/100 gr for methanol, from 306 to 407.33 mg/100 gr for ethanol , from 300 to 392 mg/100 gr for acetone and from 193 to 281.25 mg/100 gr for water. The results show that the methanol...
Optimization for Production & Purification of Asparaginase Enzyme
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Maghsodi, Vida (Supervisor)
Abstract
The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile Acute Lymphocytic Leukemia [ALL] and Lymphosarcomas. The present study discusses the studies carried out for the optimal production of the enzyme from Escherichia coli ATCC 11303. For extraction of the intracellular enzyme, Sonication is more useful method for cell disruption than alkali lysis and enzymatic method. We improved Luria Bertani (LB) media (tryptone 1% w/v,...
A wide-range pH indicator based on colorimetric patterns of gold@silver nanorods
, Article Sensors and Actuators B: Chemical ; Volume 358 , 2022 ; 09254005 (ISSN) ; Abbasi Moayed, S ; Ghasemi, F ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The potential of hydrogen (pH) is a basic and critical parameter representing the function of numerous chemicals/biomolecules. Due to the widespread applications of pH in diverse fields, the development of rapid and simple yet reliable probes for the determination of pH has attracted significant interest. In this paper, by using AuNRs, silver ions, and ascorbic acid as colorimetric pH sensor, a multicolorimetric nanosensor is described for pH measurement. The reduction of silver ions by ascorbic acid which is strongly influenced by pH, results in silver nanoshell deposition on the surface of AuNRs. Consequently, the formation of Au@Ag core-shell NRs causes a series of blue shifts in the...
Design of Colorimetric Sensor Arrays Based on Gold Nanorods for Speciation and Discrimination of Biomolecules and Environmental Pollutants
, Ph.D. Dissertation Sharif University of Technology ; Hormozinezhad, Mohammad Reza (Supervisor) ; Ghasemi, Forough (Co-Supervisor)
Abstract
The vivid optical properties of gold nanorods (AuNRs) arising from their unique structural anisotropy have been an object of fascination in a broad range of applications over the past decade. The pseudo-one-dimensional rod-shaped morphology of AuNRs underlies two distinct LSPR bands attributed to the longitudinal and the transversal oscillation of the surface plasmons. Indeed, the brilliant and high-contrast rainbow color tonality of AuNRs primarily emanates from the dramatic dependency of the location of the aforementioned bands on the aspect ratio of the nanorods. It is so profound that a minute increment of the aspect ratio is followed by a significant redshift of the longitudinal peak...
Optimization of Xanthan Gum Separation
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Maghsoudi, Vida (Co-Advisor)
Abstract
Xanthan is a water-soluble anionic polysaccharide that is produced by anaerobic fermentation using the bacterium Xanthomonas campstris. Xanthan is used in various industries, including food industry and oil industry because of its appropriate rheological properties. For this reason, various studies have been done on the production and recovery of xanthan. In this study conditions for recovery of xanthan gum were investigated and optimized by response surface methodology. Initially xanthan production under optimal conditions that determined in previous studies i.e. YM broth at 30 ⁰C without pH control was performed. After production, the gum separation was investigated using food solvents...