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    کلیدواژه های تکراریCurcumin loading potentiates the neuroprotective efficacy of Fe3O4 magnetic nanoparticles in cerebellum cells of schizophrenic rats

    , Article Biomedicine and Pharmacotherapy ; Volume 108 , 2018 , Pages 1244-1252 ; 07533322 (ISSN) Naserzadeh, P ; Ashrafi Hafez, A ; Abdorahim, M ; Abdollahifar, M. A ; Shabani, R ; Peirovi, H ; Simchi, A ; Ashtari, K ; Sharif University of Technology
    2018
    Abstract
    Background: The aim of this study was to investigate the neurotoxic effects of Fe3O4 magnetic- CurNPs on isolated schizophrenia mitochondria of rats as an in vivo model. Methods: We designed CMN loaded superparamagnetic iron oxide nanoparticles (SPIONs) (Fe3O4 magnetic- CurNPs) to achieve an enhanced therapeutic effect. The physicochemical properties of Fe3O4 magnetic- CurNPs were characterized using X-ray diffraction (XRD), and dynamic laser light scattering (DLS) and zeta potential. Further, to prove Fe3O4 magnetic- CurNPs results in superior therapeutic effects, and also, the mitochondrial membrane potential collapse, mitochondrial complex II activity, reactive oxygen species generation,... 

    The role of microstructure in mechanical behaviors of low-alloy sintered steels

    , Article Scientia Iranica ; Volume 7, Issue 1 , 2000 , Pages 41-49 ; 10263098 (ISSN) Yoozbashizadeh, H ; Simchi, A ; Moradkhani, D ; Ashtari, M ; Khorsand, H ; Davami, P ; Sharif University of Technology
    Sharif University of Technology  2000
    Abstract
    In this study, microstructural aspects that control fracture and deformation resistance of P/M materials are evaluated. Several low-alloy steels were produced under both experimental and commercial conditions for achieving different matrix phases and porosity levels with varying shape factors. A 'porosity map' was constructed and used for a quantified study of the dominant mechanism controlling mechanical behaviors. The role of inclusion gathering and secondary pores, as well as sintering mechanism and alloying method is considered and discussed. The mechanism assessment was performed by using microstructure examination through optical and scanning electron microscopy. The results... 

    Cost overrun risk assessment and prediction in construction projects: a bayesian network classifier approach

    , Article Buildings ; Volume 12, Issue 10 , 2022 ; 20755309 (ISSN) Ashtari, M. A ; Ansari, R ; Hassannayebi, E ; Jeong, J ; Sharif University of Technology
    MDPI  2022
    Abstract
    Cost overrun risks are declared to be dynamic and interdependent. Ignoring the relationship between cost overrun risks during the risk assessment process is one of the primary reasons construction projects go over budget. Conversely, recent studies have failed to account for potential interrelationships between risk factors in their machine learning (ML) models. Additionally, the presented ML models are not interpretable. Thus, this study contributes to the entire ML process using a Bayesian network (BN) classifier model by considering the possible interactions between predictors, which are cost overrun risks, to predict cost overrun and assess cost overrun risks. Furthermore, this study... 

    How do adsorbent orientation and direction of external electric field affect the charge-transfer surface-enhanced raman spectra?

    , Article Journal of Physical Chemistry C ; Volume 125, Issue 24 , 2021 , Pages 13382-13390 ; 19327447 (ISSN) Ashtari Jafari, S ; Jamshidi, Z ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    Surface-enhanced Raman spectroscopy is a highly sensitive phenomenon and a powerful fingerprint detection tool that reflects the small changes in polarizability on the pattern and intensity of Raman signals. The SERS enhancement signals elucidate with the surface-selection rules. In this regard, molecular configuration and adsorption orientation on the surface, in addition to the direction of external electric field, can lead to different patterns of SERS spectra. To evaluate how the variation of these features influences the pattern and reproducibility of the spectra, the chemical charge-transfer SERS spectra for pyridine on silver clusters are calculated for different field directions,... 

    Evaluation of Performance of Emergency Relief Vehicles Responding to Traffic Accidents in Tehran

    , M.Sc. Thesis Sharif University of Technology Ashtari, Sima (Author) ; Nassiri, Habibollah (Supervisor)
    Abstract
    High number of traffic accidents in Iran and its rate which is well above the world's average is a major issue of concern. The results of recent researches show a direct relation between survival rate of traffic accidents' injuries and the Emergency Response Time (ERT). The main objective of this research is to analyze different aspects of ERT in Tehran, Iran and to compare these results with the International standards. This study intends to compare the selected routes by ambulance drivers with the shortest paths recommended by EMME/2. Results of analysis show that when the travel time between accident scene and the emergency dispatch center is less than 8 minutes, the possibility of... 

    Synergistic coupled transport of uranyl ion across bulk liquid membrane mediated by dioxa-diazamacrocycle and oleic acid

    , Article Journal of Radioanalytical and Nuclear Chemistry ; Volume 316, Issue 1 , 2018 , Pages 9-16 ; 02365731 (ISSN) Soltani Behrooz, M ; Fasihi, J ; Samadfam, M ; Sepehrian, H ; Ashtari, P ; Mahani, M ; Arabieh, M ; Sharif University of Technology
    Springer Netherlands  2018
    Abstract
    Synergistic coupled transport of uranyl ion across a bulk liquid membrane of chloroform has been investigated using a dioxa-diazamacrocycle and oleic acid as carrier and synergistic agents, respectively. Quantitative transport of uranyl ion was achieved within 4 h when the pH of source solution was kept at 5.0–6.0 and mole ratio of carrier to synergistic agent was 1/15. It was found that overall rate and selectivity of the transport is governed by the stripping step. Finally, the influence of some foreign competitor ions including Al3+, Ca2+, CO3 2−, Cu2+, Mg2+, Pb2+, Zn2+ and Th4+ and also the ionic strength on the transport efficiency has been evaluated. © 2018, Akadémiai Kiadó, Budapest,... 

    Bootstrap-based Ensemble Clustering of Resting-state fMRI Time Series

    , M.Sc. Thesis Sharif University of Technology Ashtari, Pooya (Author) ; Vosoughi Vahdat, Bijan (Supervisor)
    Abstract
    Studies in recent years have shown formation of strongly functionally linked sub-networks during rest, networks that are often referred to as resting-state networks. RSNs not only have basic information about the brain but also play a key role in detecting brain disorders, such as Alzheimer and Autism; Consequently, they have been remarkably noticed by neuroscientists. Numerous methods have been used in order to extract RSNs using resting-states fMRI time series. Independent component analysis (ICA) is the most common method, whi have been reported to show a high level of consistency neurophysiology; however, its results is unstable in subject-level. is weakness restricted the ICA... 

    Multi-Scale Simulation of Metallic Nano-Alloy Compression Process Using Plasticity Cone-Cap Behavior Model

    , M.Sc. Thesis Sharif University of Technology Ashtari, Mehrdad (Author) ; Khoei, Amir Reza (Supervisor)
    Abstract
    The primary purpose of this study is to perform nonlinear behavior simulations in the compaction and forming of metal powders and their alloys and investigate their behavior in the plastic state. Powder compression is one of the methods of producing metal parts with high precision and improved mechanical properties, which is why it has been considered in addition to its need in the industry.There are various methods for performing these simulations, including multi-scale methods with optimal performance. Given that only the use of high-scale methods or only low-scale methods will have problems and disadvantages in such simulations, multi-scale methods will be a good alternative in which both... 

    Structural and Computational Studies of Chloro and Nitro Cobaloxime Complexes Containing Tris (p-methoxyphenyl) Phosphine Ligand

    , M.Sc. Thesis Sharif University of Technology Ashtari Larki, Mohammad (Author) ; Kia, Reza (Supervisor)
    Abstract
    In this study, two new cobaloxime complexes with molecular formula [Co(DMGH)2{P(p-PhOCH3)3}(X)] in which X= Cl, NO2 were synthesized and their structure studied. These complexes were identified by FT-IR and1H-NMR 31P{1H}-NMR methods as well as their solid state structure studied by X-ray crystallography. The non-covalent interaction of two complexes including non-classical hydrogen interactions, C─H...π interactions, and dispersion interactions were confirmed and compared theoretically and experimentally by analyzing the data extracted from X-ray single crystal diffraction  

    Supervised fuzzy partitioning

    , Article Pattern Recognition ; Volume 97 , 2020 Ashtari, P ; Nateghi Haredasht, F ; Beigy, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Centroid-based methods including k-means and fuzzy c-means are known as effective and easy-to-implement approaches to clustering purposes in many applications. However, these algorithms cannot be directly applied to supervised tasks. This paper thus presents a generative model extending the centroid-based clustering approach to be applicable to classification and regression tasks. Given an arbitrary loss function, the proposed approach, termed Supervised Fuzzy Partitioning (SFP), incorporates labels information into its objective function through a surrogate term penalizing the empirical risk. Entropy-based regularization is also employed to fuzzify the partition and to weight features,... 

    Efficient simulation of resonance Raman spectra with tight-binding approximations to density functional theory

    , Article Journal of Chemical Physics ; Volume 157, Issue 8 , Volume 157, Issue 8 , 2022 ; 00219606 (ISSN) Ashtari Jafari, S ; Jamshidi, Z ; Visscher, L ; Sharif University of Technology
    American Institute of Physics Inc  2022
    Abstract
    Resonance Raman spectroscopy has long been established as one of the most sensitive techniques for detection, structure characterization, and probing the excited-state dynamics of biochemical systems. However, the analysis of resonance Raman spectra is much facilitated when measurements are accompanied by Density Functional Theory (DFT) calculations that are expensive for large biomolecules. In this work, resonance Raman spectra are therefore computed with the Density Functional Tight-Binding (DFTB) method in the time-dependent excited-state gradient approximation. To test the accuracy of the tight-binding approximations, this method is first applied to typical resonance Raman benchmark... 

    Discussing the Behavior of the Boundary Theory Caused by Kalb-Ramond Field Perturbation in the Bulk, Using AdS/CFT Correspondence

    , M.Sc. Thesis Sharif University of Technology Ashtari Esfahani, Ali (Author) ; Arfaei, Hessamaddin (Supervisor)
    Abstract
    In this thesis we have used the low energy effective action of the string theory to find an asymptotic Anti-de sitter metric with a non-vanishing H field. Then we have used the AdS/CFT correspondence to study the effects of the added Kalb_Ramond field on two calculations in the boundary theory. The first one was the calculation of the drag force exerted on a moving quark in the quark-gluon plasma. In the second calculation we observed the effect of the added field on the confinement-de confinement phase transition  

    The role of heat treatment on wear behavior of powder metallurgy low alloy steels

    , Article Materials and Design ; Volume 23, Issue 7 , 2002 , Pages 667-670 ; 02641275 (ISSN) Khorsand, H ; Habibi, S. M ; Yoozbashizadea, H ; Janghorban, K ; Reihani, S. M. S ; Rahmani Seraji, H ; Ashtari, M ; Sharif University of Technology
    Elsevier Ltd  2002
    Abstract
    The influence of manufacturing parameters such as compacting pressure, heat treatment and microstructure on the static and dynamic properties of Fe-1.75 Ni-1.5 Cu-0.5 Mo-0.6 C was investigated. Wear and fatigue tests were carried out on reciprocate wearing and tension compression mode, respectively. The results show that delamination wear mechanism of sintered steel is similar to that of conventional wrought or cast materials. But, in sintered material, open porosity acts as sites of generation and collection of wear debris or formation of subsurface cracks. Wear rate is decreased and fatigue strength is increased by heat treatment. © 2002 Elsevier Science Ltd. All rights reserved  

    Effectiveness Evaluation of Making Natural Childbirth Free of Charge on Household Decision in Choosing Delivery Method

    , M.Sc. Thesis Sharif University of Technology Ashtari Nakhaei, Aida (Author) ; Fatemi Ardestani, Farshad (Supervisor) ; Heidarzadeh, Mohammad (Co-Advisor)
    Abstract
    The rate of cesarean section delivery in Iran is high and during the past 14 years, leading up to 2014, kept rising. In this regard, decreasing cesarean section rate was targeted through the healthcare reform plan, which was offered by Ministry of Health and Medical Education. This plan kicked off on May4, 2014. One of the most important proceedings of this plan was making natural childbirth to be free in all hospitals, which are under the auspices of the medical universities. According to healthcare utilization models, lower prices of healthcare services, more health centers and more accessibility to them, increase the probability of using health care services. Current study evaluated the... 

    Theoretical study of high repetition rate short pulse generation with fiber optical parametric amplification [electronic resource]

    , Article Journal of Lightwave Technology ; May 2012, Volume 30, Issue 9, PP. 1263-1268 Vedadi, A ; Ariaei, A. M ; Jadidi, M. M ; Salehi, J. A ; Sharif Unversity of Technology
    Abstract
    In this paper, we study theoretically the generation of high repetition rate short pulses using fiber optical parametric amplification. We show that the pulse shape and duration depend on the signal location relatively to the pump frequency. We demonstrate that in order to get the shortest pulse width, the signal must be located at one of the extremities of the gain spectrum associated with the pump peak power. We derive the analytical expression of the pulse shape in this case and compare it to the exponential gain regime case. Using numerical simulations, we also analyze the impact of walk-off and pump phase modulation that is required to suppress Stimulated Brillouin Scattering and derive... 

    A novel omega shaped microwave absorber with wideband negative refractive index for C-band applications

    , Article Optik ; Volume 242 , 2021 ; 00304026 (ISSN) Bilal, R. M. H ; Baqir, M. A ; Iftikhar, A ; Ali, M. M ; Rahim, A. A ; Niaz Akhtar, M ; Mughal, M. J ; Naqvi, S. A ; Sharif University of Technology
    Elsevier GmbH  2021
    Abstract
    This paper reports a polarization controllable and angle-insensitive perfect metamaterial absorber (PMA). The proposed PMA consists of periodically arranged asymmetric omega-shaped resonators made of metallic copper. The absorptivity was analyzed considering the microwave C-band from 4 GHz to 8 GHz. The proposed PMA shows an absorption peak with almost 100% absorptivity at 6.2 GHz. Also, wideband negative index of refraction is observed. Further, the absorber is inspected for the different rotation angles of the top metasurface (omega-shaped ring) along the optical axis, and obliquity of incidence angle for both TE and TM polarized waves. Moreover, surface electric field and surface current... 

    Explicating botanical bactericides as an intervention tool towards citrus canker

    , Article Plant Protection ; Volume 8, Issue 1 , 2024 , Pages 25-32 ; 26171279 (ISSN) Aslam, N ; Atiq, M ; Rajput, N. A ; Akram, A ; Arif, A. M ; Kachelo, G. A ; Nawaz, A ; Jahangir, M. M ; Jabbar, A ; Ijaz, A ; Sharif University of Technology
    2024
    Abstract
    Recent research efforts were made to investigate botanical bactericides as an intervention tool for citrus canker. Five botanical extracts (Eruca vesicaria, Eucalyptus globulus, Trigonella foenum-graecum, Nigella sativa, and Citrullus colocynthis) were evaluated at three different concentrations (0.25%, 0.5%, and 0.75%) against Xanthomonas citri pv. citri under in vitro conditions. Among all treatments, two effective plant extracts, alone and in combinations, were assessed at three different time points (7 days, 14 days, 21 days) under greenhouse conditions. In vitro and greenhouse experiments were conducted under a Completely Randomized Design. Results showed that C. colocynthis expressed... 

    Formal process algebraic modeling, verification, and analysis of an abstract Fuzzy Inference Cloud Service

    , Article Journal of Supercomputing ; Vol. 67, issue. 2 , February , 2014 , pp. 345-383 ; Online ISSN: 1573-0484 Rezaee, A ; Rahmani, A. M ; Movaghar, A ; Teshnehlab, M
    2014
    Abstract
    In cloud computing, services play key roles. Services are well defined and autonomous components. Nowadays, the demand of using Fuzzy inference as a service is increasing in the domain of complex and critical systems. In such systems, along with the development of the software, the cost of detecting and fixing software defects increases. Therefore, using formal methods, which provide clear, concise, and mathematical interpretation of the system, is crucial for the design of these Fuzzy systems. To obtain this goal, we introduce the Fuzzy Inference Cloud Service (FICS) and propose a novel discipline for formal modeling of the FICS. The FICS provides the service of Fuzzy inference to the... 

    Impact of holmium on structural, dielectric and magnetic properties of Cu–Zn spinel ferrites synthesized via sol–gel route

    , Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 2 , 2021 , Pages 2205-2218 ; 09574522 (ISSN) Akhter, M. J ; Khan, M. A ; Hussain, A ; Akhtar, M. N ; Ahmad, M ; Javid, M. A ; Sharif University of Technology
    Springer  2021
    Abstract
    The mixed nano-ferrites materials Cu0.6Zn0.4HoxFe2−xO4 (0.00 ≤ x ≤ 0.12) were prepared via the sol–gel auto combustion technique. The TGA curve established the annealing temperature (500 °C) for phase formation. The single exothermic peak on the DSC plot occurred at 341 °C temperature. XRD patterns of these nano ferrites verified single phase formation of the FCC cubic structure. The lattice constant a was increased from 8.4244 to 8.4419 Å and then its value decreased to 8.4319 Å. Crystallite size was found in the range of 7 to 16 nm. The surface morphology of the samples was observed from the scanning electron microscope (SEM) images. The grain size was found within the range of 90 nm to... 

    Impact of holmium on structural, dielectric and magnetic properties of Cu–Zn spinel ferrites synthesized via sol–gel route

    , Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 2 , 2021 , Pages 2205-2218 ; 09574522 (ISSN) Akhter, M. J ; Khan, M. A ; Hussain, A ; Akhtar, M. N ; Ahmad, M ; Javid, M. A ; Sharif University of Technology
    Springer  2021
    Abstract
    The mixed nano-ferrites materials Cu0.6Zn0.4HoxFe2−xO4 (0.00 ≤ x ≤ 0.12) were prepared via the sol–gel auto combustion technique. The TGA curve established the annealing temperature (500 °C) for phase formation. The single exothermic peak on the DSC plot occurred at 341 °C temperature. XRD patterns of these nano ferrites verified single phase formation of the FCC cubic structure. The lattice constant a was increased from 8.4244 to 8.4419 Å and then its value decreased to 8.4319 Å. Crystallite size was found in the range of 7 to 16 nm. The surface morphology of the samples was observed from the scanning electron microscope (SEM) images. The grain size was found within the range of 90 nm to...