Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]

, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 Pourjavadi, A. (Ali) ; Mazaheri Tehrani, Zahra ; Sharif University of Technology

Abstract

A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5

Highly efficient ring opening reactions of epoxides with deactivated aromatic amines catalyzed by heteropoly acids in water

, Article Tetrahedron ; 2007, Volume 63, Issue 4, Pages 888–891 Azizi, N. (Najmodin) ; Saidi, M. R ; Sharif University of Technology

Abstract

Heteropoly acid was found to be an effective and efficient catalyst for the ring opening reaction of epoxides with various aromatic amines to produce the corresponding β-amino alcohols in moderate to excellent yields in water. This method provides a new and efficient protocol in terms of mild reaction conditions, clean reaction profiles, small quantity of catalyst, and simple work-up procedure

LiClO4 · 3H2O promoted highly regioselective ring-opening of epoxides with thiols under neutral conditions [electronic resource]

, Article Catalysis Communications ; 2006, Volume 7, Issue 4, Pages 224–227 Azizi, N. (Najmodin) ; Saidi, M. R ; Sharif University of Technology

Abstract

A simple, rapid, atom economy and highly efficient procedure has been developed for thiolysis of epoxides by aromatic and aliphatic thiols under solvent-free conditions. A high regioselectivity in favor of nucleophilic attack at the benzylic carbon atom of aromatic epoxides, such as styrene oxide, is observed. However, aliphatic unsymmetrical alkenyl oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom. A variety of β-hydroxy sulfides were obtained in short reaction time and excellent yields with nearly complete regioselectivity

Theoretical and Computational Investigation of Quantum Plasmonic Properties of Nanocluster Dimers

, M.Sc. Thesis Sharif University of Technology Mahmoudi, Erfan (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon...

Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation

, M.Sc. Thesis Sharif University of Technology Hadi, Hossein (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic...

Investigation of Plasmonic Excitation in Carbonic Nanostructures Within Near-IR

, M.Sc. Thesis Sharif University of Technology Madadi, Mahkam (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have...

Using Nonlinear Effects of Light for Optical Signal Processing

, M.Sc. Thesis Sharif University of Technology Shatery, Farshid (Author) ; Kavehvash, Zahra (Supervisor)

Abstract

Ultrafast signal processing in time-domain with high resolution and reconfigura-bility is a challenging task. This paper, for the first time, introduces a time-varying metasurface consisting of graphene microribbon array for implementing time-lens in the terahertz domain. Given that the surface conductivity of graphene is proportional to the Fermi energy level in the THz regime, it is possible to change the phase property of the incident electromagnetic pulse by changing the Fermi level while the Fermi level itself is a function of voltage. Upon this fact, a quadratic temporal phase modulator, namely time-lens has been realized. This phase modulation is applied to the impinging signal in the...

Using Simulation-Optimization Approach for Fire Station Location and Vehicle Assignment Problem: a Case Study in Tehran, Iran

, M.Sc. Thesis Sharif University of Technology Pirmohammadi, Ali (Author) ; Amini, Zahra (Supervisor)

Abstract

In this research, the problem of locating fire stations and allocating equipment has been studied and a simulation-optimization approach has been presented to solve the problem. The mathematical models of this research were developed based on the idea of the randomness of the covered demand and the maximum expected coverage model. In these models, the issue of non-availability of equipment to cover accidents, the random nature of accidents, various fire incidents and the equipment needed to cover them are considered. Two mathematical models with deterministic and non-deterministic approach with different scenarios for demand are proposed. The non-deterministic model is developed with the aim...

Introducing An Integrated Framework For Solving The Fleet Planning Problem Using A Simulation-Optimization Approach

, M.Sc. Thesis Sharif University of Technology Sahebi, Armin (Author) ; Amini, Zahra (Supervisor)

Abstract

One of the main concerns of industrial companies’ managers is providing an efficient logistics system. To achieve an efficient logistics system, the fleet planning problem is studied by many researchers in recent years. This problem consists of multiple sub-problems at three levels: operational, tactical, and strategic. These sub-problems are closely related to each other and need to be studied and addressed in an integrated manner. In this research, an attempt is made to provide an integrated framework to solve the vehicle routing problem (operational), outsourcing problem (tactical), and fleet composition problem (strategic). These problems have various uncertainties, including customer...

Empirical study on effect of surface texture and grain size on displacement measurement of optical flow sensors

, Article 2014 2nd RSI/ISM International Conference on Robotics and Mechatronics, ICRoM 2014 ; Oct , 2014 , p. 493-497 ; ISBN: 9781479967438 Azizi, A ; Vossoughi, G ; Sharif University of Technology

2014

Abstract

Although, the optical flow sensors which are used in optical mouse have high resolution in measuring displacement, their error refrain us from a precise and reliable measurement. Besides, these sensors require calibration based on the surface. Their error has different sources and the most important is surface texture in micro level. In this research, we have worked to find surface conditions on which sensor measurement is more precise. For this aim, we used an 800 DPI low cost optical flow sensor. For making different surface textures and grains, we printed different textures with 600 and 1200DPI resolution on white paper with certain length. Then we used optical flow sensor for measuring...

A decision making model for investment and development of construction panels

, Article Journal of Forestry Research ; Volume 22, Issue 2 , May , 2011 , Pages 301-310 ; 1007662X (ISSN) Azizi, M ; Modarres, M ; Sharif University of Technology

2011

Abstract

A study was conducted to select the best alternative for the development of construction panels as well as investment in its manufacturing in Iran. Three alternatives are considered, cement-bonded wood composite product, substituted products (such as concrete panel) sandwich panel and a mixture of them. We apply the analytic network process (ANP) to achieve this goal. A hierarchy is designed to prioritize benefits, opportunities, costs and risks (BOCR) by using the Analytic Hierarchy Process (AHP) ratings approach. To evaluate the "control criteria" of the system, a control hierarchy is also created and prioritized by applying the Analytic Network Process (ANP). A total of four major control...

Energy absorption in plastic expansion of circular metal tubes

, Article Computational Plasticity X - Fundamentals and Applications, 2 September 2009 through 4 September 2009, Barcelona ; 2009 ; 9788496736696 (ISBN) Azizi, R ; Salehghaffari, S ; Sharif University of Technology

2009

Abstract

This paper investigates a new method of dissipating energy in which a rigid tube is driven into the deformable tube under axial compression. Since there is a specific clearance between the rigid and deformable tubes, the deformable tube is expanded during axial compression, and the impact energy is absorbed by plastic expansion of deformable tube and frictional energy between deformable and rigid tubes. Quasi-static axial compression tests with different values of friction coefficient between rigid and deformable tubes are performed. Theoretical formulation with consideration of strain hardening effect is presented to predict the mean crushing load. Theoretical and experimental studies show...

Modeling and control of cell cycle

, Article 3rd International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2009 ; 2009 ; 9781424429028 (ISBN) Azizi, A ; Seifipour, N ; Sharif University of Technology

2009

Abstract

Applying engineering approaches to non-engineering systems such as biological systems has brought a new research filed to the surface. The sole purpose of this research is mathematical modeling the cell cycle control system in the fissionyeast cell using Ordinary Differential Equations (ODE).This paper, in fact, introduces the capabilities of engineering knowledge and engineering of control, in particular, in this field. ©2009 IEEE

Modeling of dermal wound healing-remodeling phase by neural networks

, Article 2009 International Association of Computer Science and Information Technology - Spring Conference, IACSIT-SC 2009, Singapore, 17 April 2009 through 20 April 2009 ; 2009 , Pages 447-450 ; 9780769536538 (ISBN) Azizi, A ; Seifipour, N ; Sharif University of Technology

2009

Abstract

Wound healing is a complex biological process dependent on multiple variables: tissue oxygenation, wound size, contamination, etc. Many of these factors depend on multiple factors themselves. Mechanisms for some interactions between these factors are still unknown, presenting a barrier for scientists intending to model wound healing using an object-based programming approach. In this paper we focus on the neural networks and regard them as function approximators, and attempt to simulate remodeling phase of dermal wound healing process using neural networks as an intelligence technique. © 2009 IEEE

Mathematical modeling of dermal wound healing's remodeling phase: a finite element solution

, Article 2009 International Association of Computer Science and Information Technology - Spring Conference, IACSIT-SC 2009, Singapore, 17 April 2009 through 20 April 2009 ; 2009 , Pages 529-532 ; 9780769536538 (ISBN) Azizi, A ; Seifipour, N ; Sharif University of Technology

2009

Abstract

Though wound healing process is well-researched, this area is poorly known. One reason is that all interactions have not been discovered, the main reason, though, is that the involved processes interact in a very complicated manner with nonlinear feedback. Such complex feedback mechanisms can be easily addressed by mathematical modeling. This paper contains a review of the mathematical modeling of cell interaction with extracellular matrix components during the process of dermal wound healing with focusing on remodeling phase. The models are of partial differential equation type and solved by finite element method. © 2009 IEEE

Synthesis of Fe-Ni nano-particles by low-temperature hydrogen reduction of mechanically alloyed Ni-ferrite

, Article Journal of Alloys and Compounds ; Volume 485, Issue 1-2 , 2009 , Pages 484-487 ; 09258388 (ISSN) Azizi, A ; Sadrnezhaad, Kh ; Sharif University of Technology

2009

Abstract

Fe-Ni nano-particles were synthesized by mechanical alloying and subsequent low-temperature hydrogen reduction of oxide mixtures. First, single-phase nickel ferrite was mechanically synthesized for 30 h with steel balls to powder weight ratio of 20 while the milling was operated at 300 rpm. The as-milled powder was then placed in contact with hydrogen at 600 °C for 1 h. Reduction reactions resulted in production of Fe-Ni nano-particles. Phase identification, morphological and microstructural studies, chemical analysis and magnetic property determination were carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), energy dispersive...

A strategic model for location selection of wood industry: An application of ANP

, Article Journal of Applied Sciences ; Volume 7, Issue 3 , 2007 , Pages 326-333 ; 18125654 (ISSN) Azizi, M ; Modarres, M ; Sharif University of Technology

Asian Network for Scientific Information 2007

Abstract

The objective of this research is to design a method for selection of an appropriate location to establish plywood and veneer plants in Iran. Due to the climate of this region as well as the destruction of the forests and lack of proper plantation, the supporting forests to feed this industry are limited. Thus, it is vital to optimize the other strategically factors in order to make these plants capable of competing with the foreign plants which have access to less expensive input materials. In case of improper utilization of the resources, this industry can not compete with the imported products. The decision is made within the framework of benefits, opportunities, costs and risks (BOCR)....

Explaining integration of evidence separated by temporal gaps with frontoparietal circuit models

, Article Neuroscience ; Volume 509 , 2023 , Pages 74-95 ; 03064522 (ISSN) Azizi, Z ; Ebrahimpour, R ; Sharif University of Technology

Elsevier Ltd 2023

Abstract

Perceptual decisions rely on accumulating sensory evidence over time. However, the accumulation process is complicated in real life when evidence resulted from separated cues over time. Previous studies demonstrate that participants are able to integrate information from two separated cues to improve their performance invariant to an interval between the cues. However, there is no neural model that can account for accuracy and confidence in decisions when there is a time interval in evidence. We used behavioral and EEG datasets from a visual choice task —Random dot motion— with separated evidence to investigate three candid distributed neural networks. We showed that decisions based on...

Describing Measurment Apparatus by Hidden Variables in the Deduction of Bell Inequality

, M.Sc. Thesis Sharif University of Technology Azizi, Arash (Author) ; Golshani, Mehdi (Supervisor)

Abstract

Quantum Mechanics, as the most famous physical theory was founded about 85 years ago; but still there are a lot of debates about its interpretation. In this work, we review some basic concepts of Quantum Mechanics in form of questions about uncertainty principle, measurement problem and complementarily. We also review Bell inequality which has great philosophical and recently technological results. Bell derived his inequality regardless of modeling the measuring apparatus; we show, by take a realistic model for measuring apparatus, Bell inequality would be deduced. Finally we review a mathematical language which was used to show the duality of wave and particle. Quantum...

Payment Cost Minimization-Based Short-Term Unit Commitment Considering Incentive-Based Demand

, M.Sc. Thesis Sharif University of Technology Azizi, Ali (Author) ; Hoseini, Hamid (Supervisor)

Abstract

After restructuring in power systems, Independent System Operators (ISO's) are looked for an appropriate auction mechanism to find the market operation point. In deregulated electricity markets, Offer Cost Minimization (OCM) auction is used to minimize the total bid cost for selecting offer and demand bids. But a uniform market clearing price (MCP) or Locational Marginal Price (LMP) is used for consumer payments. Hence, the minimized bid cost is different from settlement cost. The used mechanisms are for manufactures offer and their cost functions optimization. The Payment Cost Minimization (PCM) is one of the mechanims that affect directly on the consumers payment and lead to reduction of...