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    The controlled release of dexamethasone sodium phosphate from bioactive electrospun PCL/gelatin nanofiber scaffold

    , Article Iranian Journal of Pharmaceutical Research ; Volume 18, Issue 1 , 2019 , Pages 111-124 ; 17350328 (ISSN) Boroojeni, F. R ; Mashayekhan, S ; Abbaszadeh, H. A ; Sharif University of Technology
    Iranian Journal of Pharmaceutical Research  2019
    In this study, a system of dexamethasone sodium phosphate (DEXP)-loaded chitosan nanoparticles embedded in poly-ε-caprolacton (PCL) and gelatin electrospun nanofiber scaffold was introduced with potential therapeutic application for treatment of the nervous system. Besides anti-inflammatory properties, DEXP act through its glucocorticoid receptors, which are involved in the inhibition of astrocyte proliferation and microglial activation. Bovine serum albumin (BSA) was used to improve the encapsulation efficiency of DEXP within chitosan nanoparticles and to overcome its initial burst release. BSA incorporation within the chitosan nanoparticles increased the encapsulation efficiency of DEXP... 

    Resisting Flow Content Characterization in Network Traffic

    , M.Sc. Thesis Sharif University of Technology Momeni Boroojeni, Farzad (Author) ; Kharrazi, Mehdi (Supervisor)
    One way to control the type of data being transferred in the network is to check the header of the packet, but in networks that have high-speed data transmission or data can move through different routes, the probability of finding the first packet which contains the header reduces tremendously, and the usage of the methods mentioned below becomes clear. So even if the packet header isn’t received correctly, or the declarative features of these flows are changed, without having exact knowledge of the data transferred, you can use a limited number of packets to obtain information such as the type and protocol being used. This is possible with the help of statistical data analysis.Traffic... 

    Descriptive Complexity for Counting Problems

    , M.Sc. Thesis Sharif University of Technology Yaghoubi, Omid (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    Descriptive complexity refers to the difficulty of expressing a problem in a formal language, allowing for a complete and precise description of the problem, including output specifications for function problems. Despite the success of the descriptive approach in computational complexity, this approach has been predominantly used for decision problems. In contrast to decision problems, a counting problem can be considered as a function with the range of natural numbers. This thesis focuses on the examination of counting problems from a descriptive perspective, exploring the connection between their descriptive and computational versions. Toward this goal, weighted logic is utilized to... 

    Bioinspired nanofiber scaffold for differentiating bone marrow-derived neural stem cells to oligodendrocyte-like cells: Design, fabrication, and characterization

    , Article International Journal of Nanomedicine ; Volume 15 , 2020 , Pages 3903-3920 Boroojeni, F. R ; Mashayekhan, S ; Abbaszadeh, H. A ; Ansarizadeh, M ; Khoramgah, M. S ; Rahimi Movaghar, V ; Sharif University of Technology
    Dove Medical Press Ltd  2020
    Background: Researchers are trying to study the mechanism of neural stem cells (NSCs) differentiation to oligodendrocyte-like cells (OLCs) as well as to enhance the selective differentiation of NSCs to oligodendrocytes. However, the limitation in nerve tissue acces-sibility to isolate the NSCs as well as their differentiation toward oligodendrocytes is still challenging. Purpose: In the present study, a hybrid polycaprolactone (PCL)-gelatin nanofiber scaffold mimicking the native extracellular matrix and axon morphology to direct the differentiation of bone marrow-derived NSCs to OLCs was introduced. Materials and Methods: In order to achieve a sustained release of T3, this factor was... 

    Effect of Carbon Content on Mechanical Properties of TLP Bonded Ferrite- Martensite Dual Phase Steels

    , M.Sc. Thesis Sharif University of Technology Elyasi Boroojeni, Forood (Author) ; Ekrami, Ali Akbar (Supervisor)
    During the last few years researchers have drawn much attention to HSLA steels because of the application of these steels in many industries. Ferrite-martensite dual phase(DP) steels are one of the most common HSLA steels which are currently used. Combination of these two phases provides good strength along with good ductility. Joining and welding of these steels has always been an important challenge. The aim of this study is to examine applicability of TLP method for joining and dual phase processing of this steels at the same time. Microstructural and mechanical examination of the bonded specimens showed that isothermal solidification occurred during holding for 50 min at the... 

    Dynamic Simulation of Liquid Direct Methanol Fule Cell

    , M.Sc. Thesis Sharif University of Technology Akbarpoor Boroojeni, Behrouz (Author) ; Pishvaei, Mahmood Reza (Supervisor)
    Cell of fuel methanol can store fuel easily, because they can suitable for resources of energy with ambulant applications. As for with the extensive of electrical haul instruments, they attention to the use of fuel cell methanol. In this project a fuel cell methanol consist of different branches such as cathode, Anode, substrates of membrane and influx, has modeled with the form of flat three dimensional. This model consist of ambulant theorems, transfer of mass, chemistry theorems and reflexes of electro chemistry in spongy environment. As for with a little knowledge that is related to the oxidation of methanol, the first research is related to this reflex and the knowledge of mathematic... 

    Algebraic and Combinatorial Bounds for the Hat Guessing Number of Graphs

    , M.Sc. Thesis Sharif University of Technology Shariati, Mohammad Reza (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    A number of players are positioned on the vertices of a finite graph, and each is wearing a hat whose color has been randomly and equally likely selected from a finite set of colors. Player A sees Player B if and only if there is a directed edge from the vertex corresponding to A to the vertex corresponding to B. The players must agree on a specific strategy before the game begins and carry it out. Once the game begins, no communication is allowed between the players, and each player must simultaneously guess the color of their own hat. The team wins if at least one guess is correct. For a given directed graph, we define the 'guessing number' of the graph as the maximum number of colors for... 

    Releasing All-Pairs Shortest Distances of Public Graphs with Differential Privacy

    , M.Sc. Thesis Sharif University of Technology Tofighi Mohammadi, Alireza (Author) ; Ebrahimi Boroojeni, Javad (Supervisor)
    In the context of differential privacy, a data holder has confidential information about users. The goal is to provide a randomized algorithm that takes this information as input and outputs an aggregation of the input. The algorithm must have the property that for any neighboring input pairs, the output distribution of the algorithm is close. One problem in differential privacy research is the release of shortest distances in a weighted graph. This model, first studied by Adam Sealfon, involves an edge-weighted graph G=(V, E) with weights w : E → R, where the topology of the graph is public and the private information is the weight of the edges. The aim is to provide an (ϵ, δ)-DP algorithm... 

    Conductive nanofiber scaffold for bone tissue engineering

    , Article 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Rasti Boroojeni, F ; Mashayekhan, S ; Abbaszadeh, H. A ; Ansarizadeh, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    In order to fabricate nanofiber scaffold for bone tissue engineering, electrospinning technique was employed. This technique produces nanofiberous scaffold supporting cell adhesion, migration, and proliferation. Here, we developed a novel conductive scaffold from poly-caprolactone, gelatin, and poly aniline/graphene nanoparticles. In this study, co-electrospinning was utilized to fabricate composite electrospun scaffold. The effect of polyaniline/graphene (PAG) nanoparticles on the mechanical properties and electrical conductivity of this hybrid scaffold was investigated. The result showed that PAG nanoparticles enbance both mechanical properties and electrical conductivity of the scaffolds.... 

    Some relations between rank of a graph and its complement

    , Article Linear Algebra and Its Applications ; Volume 422, Issue 1 , 2007 , Pages 341-347 ; 00243795 (ISSN) Akbari, S ; Alipour, A ; Ebrahimi Boroojeni, J ; Ghorbani, E ; Mirjalalieh Shirazi, M ; Sharif University of Technology
    Let G be a graph of order n and rank(G) denotes the rank of its adjacency matrix. Clearly, n ≤ rank (G) + rank (over(G, -)) ≤ 2 n. In this paper we characterize all graphs G such that rank (G) + rank (over(G, -)) = n, n + 1 or n + 2. Also for every integer n ≥ 5 and any k, 0 ≤ k ≤ n, we construct a graph G of order n, such that rank (G) + rank (over(G, -)) = n + k. © 2006 Elsevier Inc. All rights reserved  

    Design and Fabrication of Bioactive Nano Fibrous Scaffold for Central Nervous Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Rasti Boroojeni, Fatemeh (Author) ; Mashayekhan, Shohreh (Supervisor) ; Abbaszadeh, Hojjatollah (Supervisor) ; Hasannejad, Zahra (Co-Advisor)
    A system of electrospun scaffold containing drug-loaded chitosan nanoparticles was introduced for using in spinal cord tissue engineering. In spinal cord injury treatment, the formation of glial scar after injury which contains proteoglycans and activate glial cells should be avoided. In this study, the release of Dexamethasone sodium phosphate (DEXP) as a steroid anti-inflammatory agent from electrospun nanofiber composite containing chitosan nanoparticles was investigated. DEXP is believed to act through its glucocorticoid receptors found in most neurons and glial cells. These receptors’ pathways are involved in the inhibition of astrocyte proliferation and microglial activation.... 

    A new study in designing MTMDs in SDOF and MDOF systems based on the spectral analysis method

    , Article Earthquake and Structures ; Volume 19, Issue 4 , 2020 , Pages 243-259 Baigoly, M ; Shargh, F. H ; Rofooei, F. R ; Sharif University of Technology
    Techno-Press  2020
    This study aims to optimize, design, and predict the MTMDs performance in SDOF systems using spectral analysis, and then apply their results to MDOF structures. Given the importance of spectral analysis in the design of new engineering structures, achieving a method for designing TMDs based on this theory can be of great importance for structural designers. In this study, several convenient combinations of MTMDs in an SDOF system are first considered to minimize the maximum displacement. For calculating the frequency ratios of dampers, an innovative technique is adopted in which the values of different modal responses obtained from the spectral analysis are approached together. This... 

    NLOS identification in range-based source localization: statistical approach

    , Article IEEE Sensors Journal ; Volume 18, Issue 9 , 1 May , 2018 , Pages 3745-3751 ; 1530437X (ISSN) Abolfathi Momtaz, A ; Behnia, F ; Amiri, R ; Marvasti, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Least squares estimation is a widely-used technique for range-based source localization, which obtains the most probable position of mobile station. These methods cannot provide desirable accuracy in the case with a non line of sight (NLOS) path between mobile station and base stations. To circumvent this drawback, many algorithms have been proposed to identify and mitigate this error; however, they have a large run-time overhead. On the other hand, new positioning systems utilize a large set of base stations, and a practical algorithm should be fast enough to deal with them. In this paper, we propose a novel algorithm based on subspace method to identify and eliminate the NLOS error.... 

    Asymptotic bounds on the optimum multiuser efficiency of randomly spread CDMA

    , Article 2014 12th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, WiOpt 2014 ; May , 2014 , pp. 599-603 ; ISBN: 9783901882630 Sedaghat, M. A ; Muller, R. R ; Marvasti, F ; Sharif University of Technology
    We derive some bounds on the Optimum Asymptotic Multiuser Efficiency (OAME) of randomly spread CDMA as extensions of the result by Tse and Verdú. To this end, random Gaussian and random binary antipodal spreading are considered. Furthermore, the input signal is assumed to be Binary Phase Shift Keying (BPSK). It is shown that in a CDMA system with K-user and N chips when K and N → 8 and the loading factor, K over N, grows logarithmically with K, the OAME converges to 1 almost surely under some condition. It is also shown that a Gaussian randomly spread CDMA system has a performance close to the single user system at high Signal to Noise Ratio (SNR) when the loading factor is kept less than... 

    Performance analysis of asynchronous optical code division multiple access with spectral-amplitudecoding

    , Article IET Communications ; Vol. 8, Issue. 6 , April , 2014 , pp. 956-963 ; ISSN: 17518628 Sedaghat, M. A ; Muller, R. R ; Marvasti, F ; Sharif University of Technology
    In this study, the performance of a spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) system in the asynchronous regime is evaluated using a Gaussian approximation of the decision variable for codes with fixed cross-correlation used in SAC-OCDMA systems. The authors consider the effect of phase-induced intensity noise (PIIN), thermal noise and shot noise. Moreover, the validity of the Gaussian approximation is confirmed by a Kolmogorov-Smirnov fitness test. For sake of comparison, the bit error rate (BER) of the asynchronous SAC-OCDMA system is also plotted numerically in comparison with the BER of the synchronous SAC-OCDMA. They show that a SAC-OCDMA system without... 

    On optimum asymptotic multiuser efficiency of randomly spread CDMA

    , Article IEEE Transactions on Information Theory ; Volume 61, Issue 12 , 2015 , Pages 6635-6642 ; 00189448 (ISSN) Sedaghat, M. A ; Müller, R. R ; Marvasti, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    We extend the result by Tse and Verdú on the optimum asymptotic multiuser efficiency of randomly spread code division multiple access (CDMA) with binary phase shift keying input. Random Gaussian and random binary antipodal spreading are considered. We obtain the optimum asymptotic multiuser efficiency of a K-user system with spreading gain N when K and N → ∞ and the loading factor, (K/N) , grows logarithmically with K under some conditions. It is shown that the optimum detector in a Gaussian randomly spread CDMA system has a performance close to the single user system at high signal-to-noise ratio when K and N → ∞ and the loading factor, (K/N), is kept less than (log3 K/2). Random binary... 

    Efficient Friedel-crafts alkylation of indoles and pyrrole with enones and nitroalkene in water

    , Article Organic and Biomolecular Chemistry ; 2006, Volume 4, Issue 23, Pages 4275-4277 Azizi, N. (Najmodin) ; Arynasab, F ; Saidi, M. R ; Sharif University of Technology
    An operationally simple and entirely green protocol for heteropoly acid catalyst conjugate addition of indoles and pyrrole to unsaturated carbonyl compounds and nitro-alkene in water was investigated. It is important that the products arising from 1,2-addition were not observed under the reaction conditions. Pyrroles also readily underwent Michael addition at Α-positions under the same reaction conditions. Indole and many of its derivatives are present in many substances commonly found in nature. Micheal addition reactions are performed in organic solvents with the reactions in water are relatively scarce. The Michael addition between indole and methyl vinyl ketone in the presence of... 

    Straightforward and highly efficient catalyst-free one-pot synthesis of dithiocarbamates under solvent-free conditions

    , Article Organic Letters ; Volume 8, Issue 23, 9 November 2006, Pages 5275-5277 Azizi, N. (Najmodin) ; Aryanadab, F ; Saidi, M. R ; Sharif University of Technology
    A highly efficient and simple synthesis of dithiocarbamates is possible based on the one-pot reaction of amines, CS2, and alkyl halides without using a catalyst under solvent-free conditions. The mild reaction conditions, high yields, and broad scope of the reaction illustrate the good synthetic utility of this method. The reaction is a highly atom-economic process for production of S-alkyl thiocarbamates and successfully can be used in high quantities in the pharmaceutical or agrochemical industries  

    Performance evaluation of disk type variable reluctance resolvers

    , Article IEEE Sensors Journal ; Volume 17, Issue 13 , 2017 , Pages 4037-4045 ; 1530437X (ISSN) Nasiri Gheidari, Z ; Alipour Sarabi, R ; Tootoonchian, F ; Zare, F ; Sharif University of Technology
    In this paper, a new disk type variable reluctance (DTVR) resolver is introduced. The proposed resolver works based on the sinusoidal variation of the coupling area between stator and rotor. An analytical model based on winding function theory is proposed for the performance analysis of the sensor. Then, the influence of stator slot shape, radial and peripheral slot width, pole numbers, and slot skewing and harmonic injection into the rotor couture on the accuracy of the proposed resolver is examined. The 3-D time stepping finite element method is used to show the effect of optimizations. Finally, the prototypes of the two-pole, four-pole, and eight-pole DTVR resolvers are constructed and... 

    Local density variation of gold nanoparticles in aquatic environments

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 84 , 2016 , Pages 489-497 ; 13869477 (ISSN) Hosseinzadeh, F ; Shirazian, F ; Shahsavari, R ; Khoei, A. R ; Sharif University of Technology
    Elsevier  2016
    Gold (Au) nanoparticles are widely used in diagnosing cancer, imaging, and identification of therapeutic methods due to their particular quantum characteristics. This research presents different types of aqueous models and potentials used in TIP3P, to study the effect of the particle size and density of Au clusters in aquatic environments; so it can be useful to facilitate future investigation of the interaction of proteins with Au nanoparticles. The EAM potential is used to model the structure of gold clusters. It is observed that in the systems with identical gold/water density and different cluster radii, gold particles are distributed in aqueous environment almost identically. Thus, Au...