Search for: nitric-oxide
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    Improvement and experimental validation of a multi-zone model for combustion and NO emissions in CNG fueled spark ignition engine

    , Article Journal of Mechanical Science and Technology ; Volume 26, Issue 4 , 2012 , Pages 1205-1212 ; 1738494X (ISSN) Asgari, O ; Hannani, S. K ; Ebrahimi, R ; Sharif University of Technology
    This article reports the experimental and theoretical results for a spark ignition engine working with compressed natural gas as a fuel. The theoretical part of this work uses a zero-dimensional, multi-zone combustion model in order to predict nitric oxide (NO) emission in a spark ignition (SI) engine. The basic concept of the model is the division of the burned gas into several distinct zones for taking into account the temperature stratification of the burned mixture during combustion. This is especially important for accurate NO emissions predictions, since NO formation is strongly temperature dependent. During combustion, 12 products are obtained by chemical equilibrium via Gibbs energy... 

    Study of Change of Thermochemical Properties of DNA bases in the Presence of Neutral, Anionic, and Radical Species

    , M.Sc. Thesis Sharif University of Technology Mottaghizadeh, Ayda (Author) ; Fattahi, Alireza (Supervisor)
    Since we are exposed to many air pollutants such as different gases daily, this project has attempted to investigate how these gases affect nucleobases, which are the main constituent of the DNA chain. The gases used in this study are sulfur dioxide (SO2), carbon monoxide (CO) and nitric oxide (NO). Each of these gases was studied separately along with the most stable nucleobase in the neutral, anionic and cationic states. The AT and GC base pairs were also exposed to each of these gases and changes (for exampl, the acidity, proton affinity) created in the AT and GC base pairs were examined.The most important properties studied during this project include gas-nucleobase interactions, proton... 

    Simulation of NO Production Process from Endothelial Cells and its Effect on Coronary Artery Flow Field

    , M.Sc. Thesis Sharif University of Technology Shahriari, Amir Hossein (Author) ; Firoozabadi, Bahar (Supervisor)
    Endothelial derived nitric oxide (NO) and its role in regulating the physiological conditions of blood vessels is one of the favorite topics among researchers. The majority of previous studies have focused on nitric oxide transport in blood vessels, less attention has been paid to its vasodilative effects in blood vessels. The main aim of this study is to propose an integrated model to study the effects of endothelial-derived nitric oxide on hemodynamic conditions of blood vessels. Nitric oxide is produced by endothelial cells upon exposure to mechanical forces such as hemodynamic shear stress. The synthesized nitric oxide then diffuses into the neighboring vascular smooth cells, where it... 

    Cyto and genotoxicities of graphene oxide and reduced graphene oxide sheets on spermatozoa

    , Article RSC Advances ; Vol. 4, issue. 52 , May , 2014 , pp. 27213-27223 ; ISSN: 20462069 Hashemi, E ; Akhavan, O ; Shamsara, M ; Rahighi, R ; Esfandiar, A ; Tayefeh, A. R ; Sharif University of Technology
    Concentration-dependent cyto and genotoxicities of graphene oxide (GO) and reduced GO (rGO) sheets on spermatozoa were studied. rGO sheets with various surface chemical states were achieved using hydrazine (N2H 4) hydrothermal (HT) reactions and green tea polyphenols (GTPs). Although 0.1 μg mL-1 graphene could not change sperm viability and kinetic parameters, <40% and 20% of spermatozoa were viable and progressively motile, after 2 h incubation with 400 μg mL-1 GO or rGO, respectively. All the graphene nanomaterials induced concentration- dependent reductions of adenosine triphosphate and NAD+/NADH produced by spermatozoa for motility and metabolic activity. While GO, N 2H4-rGO, and HT-rGO... 

    Effects of short term and long term Extremely Low Frequency Magnetic Field on depressive disorder in mice: Involvement of nitric oxide pathway

    , Article Life Sciences ; Volume 146 , 2016 , Pages 52-57 ; 00243205 (ISSN) Madjid Ansari, A ; Farzam Pour, S ; Sadr, A ; Shekarchi, B ; Majid Zadeh, A. K ; Sharif University of Technology
    Elsevier Inc 
    Aims Previous reports on the possible effects of Extremely Low Frequency Magnetic Fields (ELF MF) on mood have been paradoxical in different settings while no study has yet been conducted on animal behavior. In addition, it was shown that ELF MF exposure makes an increase in brain nitric oxide level. Therefore, in the current study, we aimed to assess the possible effect(s) of ELF MF exposure on mice Forced Swimming Test (FST) and evaluate the probable role of the increased level of nitric oxide in the observed behavior. Main methods Male adult mice NMRI were recruited to investigate the short term and long term ELF MF exposure (0.5 mT and 50 Hz, single 2 h and 2 weeks 2 h a day). Locomotor... 

    A validated reduced-order dynamic model of nitric oxide regulation in coronary arteries

    , Article Computers in Biology and Medicine ; Volume 139 , 2021 ; 00104825 (ISSN) Moshfegh, H ; Tajeddini, F ; Pakravan, H. A ; Mahzoon, M ; Azadi Yazdi, E ; Bazrafshan Drissi, H ; Sharif University of Technology
    Elsevier Ltd  2021
    Nitric Oxide (NO) provides myocardial oxygen demands of the heart during exercise and cardiac pacing and also prevents cardiovascular diseases such as atherosclerosis and platelet adhesion and aggregation. However, the direct in vivo measurement of NO in coronary arteries is still challenging. To address this matter, a mathematical model of dynamic changes of calcium and NO concentration in the coronary artery was developed for the first time. The model is able to simulate the effect of NO release in coronary arteries and its impact on the hemodynamics of the coronary arterial tree and also to investigate the vasodilation effects of arteries during cardiac pacing. For these purposes, flow... 

    A novel regression imputation framework for Tehran air pollution monitoring network using outputs from WRF and CAMx models

    , Article Atmospheric Environment ; Volume 187 , 2018 , Pages 24-33 ; 13522310 (ISSN) Shahbazi, H ; Karimi, S ; Hosseini, V ; Yazgi, D ; Torbatian, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Missing or incomplete data in short or long intervals is a common problem in measuring air pollution. Severe issues may arise when dealing with missing data for time-series prediction schemes or mean analysis. This study aimed to develop a new regression imputation framework to impute missing values in the hourly air quality data set of Tehran and enhance the applicability of Tehran Air Pollution Forecasting System (TAPFS). The proposed framework was designed based on three types of features including measurements of other stations, WRF and CAMx physical models. In this framework, elastic net and neuro-fuzzy networks were efficiently combined in a two-layer structure. The framework was... 

    Co-doping a metal (Cr, Mn, Fe, Co, Ni, Cu, and Zn) on Mn/ZSM-5 catalyst and its effect on the catalytic reduction of nitrogen oxides with ammonia

    , Article Research on Chemical Intermediates ; Volume 43, Issue 4 , 2017 , Pages 2143-2157 ; 09226168 (ISSN) Saeidi, M ; Hamidzadeh, M ; Sharif University of Technology
    Springer Netherlands  2017
    Selective catalytic reduction (SCR) of NOx by NH3 over a series of Mn–M/Z catalysts (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, and Z = the ZSM-5 Zeolite) synthesized by wet impregnation method was investigated. Mn–Fe/Z, Mn–Co/Z, and Mn–Cu/Z catalysts exhibited approximately 100 % NOx conversion over a wide temperature range (200–360 °C) in a defined atmospheric condition, which was noticeably greater than that of Mn–Cr/Z (340–360 °C). Furthermore, the effect of addition of second metal oxide species to the initial Mn/Z catalyst on the structure of catalysts was studied by several characterization techniques. BET measurements revealed high surface area and pore volume of the Mn–Cu/Z catalyst. In... 

    Predicting hourly air pollutant levels using artificial neural networks coupled with uncertainty analysis by Monte Carlo simulations

    , Article Environmental Science and Pollution Research ; Volume 20, Issue 7 , 2013 , Pages 4777-4789 ; 09441344 (ISSN) Arhami, M ; Kamali, N ; Rajabi, M. M ; Sharif University of Technology
    Recent progress in developing artificial neural network (ANN) metamodels has paved the way for reliable use of these models in the prediction of air pollutant concentrations in urban atmosphere. However, improvement of prediction performance, proper selection of input parameters and model architecture, and quantification of model uncertainties remain key challenges to their practical use. This study has three main objectives: to select an ensemble of input parameters for ANN metamodels consisting of meteorological variables that are predictable by conventional weather forecast models and variables that properly describe the complex nature of pollutant source conditions in a major city, to... 

    Long-term investigation on the phase stability, magnetic behavior, toxicity, and MRI characteristics of superparamagnetic Fe/Fe-oxide core/shell nanoparticles

    , Article International Journal of Pharmaceutics ; Volume 439, Issue 1-2 , 2012 , Pages 28-40 ; 03785173 (ISSN) Masoudi, A ; Madaah Hosseini, H. R ; Seyed Reyhani, S. M ; Shokrgozar, M. A ; Oghabian, M. A ; Ahmadi, R ; Sharif University of Technology
    To efficiently enhance the contrast obtaining from magnetic resonance imaging (MRI), pharmaceutical grade colloidal dispersions of PEG coated iron-based nanoparticles were prepared and compared to conventional pure iron oxide contrast agent. In this study, we synthesized ∼14 nm iron nanoparticles via NaBH4 reduction of iron(III) chloride in an aqueous medium. The resulting nanoparticles were further oxidized by two different methods via (CH3)3NO oxygen transferring agent and exposure to oxygen flow. XRD and electron microscopy analyses confirmed the formation of a second layer on the surface of α-Fe core. As magnetic measurements and Mössbauer spectra of 4-months post prepared nanoparticles... 

    Associations of primary and secondary organic aerosols with airway and systemic inflammation in an elderly panel cohort

    , Article Epidemiology ; Volume 21, Issue 6 , 2010 , Pages 892-902 ; 10443983 (ISSN) Delfino, R. J ; Staimer, N ; Tjoa, T ; Arhami, M ; Polidori, A ; Gillen, D. L ; George, S. C ; Shafer, M. M ; Schauer, J. J ; Sioutas, C ; Sharif University of Technology
    Background: Exposure-response information about particulate air-pollution constituents is needed to protect sensitive populations. Particulate matter <2.5 mm (PM 2.5) components may induce oxidative stress through reactive-oxygen-species generation, including primary organics from combustion sources and secondary organics from photochemically oxidized volatile organic compounds. We evaluated differences in airway versus systemic inflammatory responses to primary versus secondary organic particle components, particle size fractions, and the potential of particles to induce cellular production of reactive oxygen species. Methods: A total of 60 elderly subjects contributed up to 12 weekly... 

    Production of perovskite catalysts on ceramic monoliths with nanoparticles for dual fuel system automobiles

    , Article International Journal of Environmental Science and Technology ; Volume 6, Issue 1 , 2009 , Pages 105-112 ; 17351472 (ISSN) Khanfekr, A ; Arzani, K ; Nemati, A ; Hosseini, M ; Sharif University of Technology
    CEERS  2009
    (Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen)3- Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with XU7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as palladium, platinum and rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of... 

    Recent progress in inorganic and composite coatings with bactericidal capability for orthopaedic applications

    , Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 7, Issue 1 , Feb , 2011 , Pages 22-39 ; 15499634 (ISSN) Simchi, A ; Tamjid, E ; Pishbin, F ; Boccaccini, A. R ; Sharif University of Technology
    This review covers the most recent developments of inorganic and organic-inorganic composite coatings for orthopedic implants, providing the interface with living tissue and with potential for drug delivery to combat infections. Conventional systemic delivery of drugs is an inefficient procedure that may cause toxicity and may require a patient's hospitalization for monitoring. Local delivery of antibiotics and other bioactive molecules maximizes their effect where they are required, reduces potential systemic toxicity and increases timeliness and cost efficiency. In addition, local delivery has broad applications in combating infection-related diseases. Polymeric coatings may present some...