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    Artificial neural network aided design of a multi-component catalyst for the steam reforming of methanol

    , Article Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry ; Volume 44, Issue 1 , 2005 , Pages 64-66 ; 03764710 (ISSN) Jooya, Sh ; Gobal, F ; Sharif University of Technology
    A neural network based on the feed forward back propagation error has been developed for the design and simulation of the catalytic properties of a multi-component system based on Cu-M-Al2O3 (M=Zn,Cr,Zr) for the steam reforming of methanol. Due to the limited size of the data set, cross validation method has to be used to enhance and also evaluate the prediction ability of the network. The best structural organization has been found to include 4,3,6,3 nodes in the input, two hidden layers and the output layer respectively  

    Preparation of a naltrexone HCL potentiometric sensor and its application to pharmaceutical analysis and drug determination in biological fluids

    , Article Journal of Food and Drug Analysis ; Volume 19, Issue 4 , 2011 , Pages 445-451+539 ; 10219498 (ISSN) Ghorbani Bidkorbeh, F ; Shahrokhian, S ; Mohammadi, A ; Dinarvand, R ; Sharif University of Technology
    A novel ion selective electrode is fabricated for naltrexone HCl and used in pharmaceutical analysis and drug determination in biological fluids without complicated pretreatments and extractions, using direct potentiometry. The naltrexone complex with sodium tetraphenyl borate (NaTPB) is obtained by in situ soaking PVC membrane electrode in an 1 × 10 -3 M naltrexone solution. The sensor exhibited fast, reproducible and linear sub-Nernstian response over concentration range of 1 × 10 -5 - 1 × 10 -3 M with a detection limit of 5 × 10 -6 M. The membrane sensor was successfully applied to the determination of naltrexone in capsules as well as for its determination in urine and plasma samples  

    QSAR analysis of platelet-derived growth inhibitors using GA-ANN and shuffling crossvalidation

    , Article QSAR and Combinatorial Science ; Volume 27, Issue 6 , 2008 , Pages 750-757 ; 1611020X (ISSN) Jalali Heravi, M ; Asadollahi Baboli, M ; Sharif University of Technology
    Quantitative Structure - Activity Relationship (QSAR) models for the inhibition action of some 1-phenylbenzimidazoles on platelet-derived growth are constructed using Genetic Algorithm and Artificial Neural Network (GA-ANN) method. The statistical parameters of R2 and root-mean-square error are 0.82 and 0.21, respectively using this method. These parameters show a considerable improvement compared to the stepwise multiple linear regression combined with ANN (stepwise MLR-ANN). Ten-fold shuffling crossvalidations are carried out to select the most important descriptors. Five descriptors of index of Balaban (J), average molecular weight (AMW), 3D-Wiener index (W3D), mean atomic van der Waals... 

    Comparison of Shuffling-Adaptive Neuro Fuzzy Inference System (Shuffling-ANFIS) with conventional ANFIS as feature selection methods for nonlinear systems

    , Article QSAR and Combinatorial Science ; Volume 26, Issue 10 , 2007 , Pages 1046-1059 ; 1611020X (ISSN) Jalali Heravi, M ; Kyani, A ; Sharif University of Technology
    This paper compares the Shuffling-Adaptive Neuro Fuzzy Inference System (Shuffling-ANFIS) with conventional ANFIS as the method for selecting the features of nonlinear systems. Shuffling-ANFIS technique uses the advantage of data splitting with the ANFIS as a powerful feature selection method to select the most important factors affecting nonlinear phenomena. In this technique, the features with the largest percent of frequency can be found by running the conventional ANFIS sequential forward search on the large number of training and test sets using leave-one-out validation criteria. The superiority of Shuffling-ANFIS over the conventional ANFIS was evaluated by using two synthetic and one... 

    On-line micro solid-phase extraction of clodinafop propargyl from water, soil and wheat samples using electrospun polyamide nanofibers

    , Article Chromatographia ; Vol. 77, issue. 9-10 , May , 2014 , p. 723-728 Bagheri, H ; Asgari, S ; Piri-Moghadam, H ; Sharif University of Technology
    An on-line extraction/determination set up was designed for micro solid-phase extraction of clodinafop propargyl from water, soil and wheat samples using electrospun polyamide nanofiber mats. The prepared mats were packed in a stainless steel tube which conveniently acted as a high-performance liquid chromatography injection loop. Influential parameters affecting the extraction efficiency were optimized using a distilled water sample fortified with 25 μg L-1 of clodinafop propargyl. An enrichment factor of 440 was achieved for clodinafop propargyl indicating the ability of the whole procedure. Under the optimum conditions, the linearity for the analyte was in the range of 6-700 μg L-1, while... 

    Numerical investigation on the solid flow pattern in bubbling gas-solid fluidized beds: Effects of particle size and time averaging

    , Article Powder Technology ; Vol. 264, issue , September , 2014 , p. 466-476 Askarishahi, M ; Salehi, M. S ; Molaei Dehkordi, A ; Sharif University of Technology
    The effects of particle size on the solid flow pattern in gas-solid bubbling fluidized beds were investigated numerically using two-fluid model based on the kinetic theory of granular flow. In this regard, the set of governing equations was solved using finite volume method in two-dimensional Cartesian coordinate system. Glass bead particles with mean sizes of 880. μm, 500. μm, and 351. μm were fluidized by air flow at excess gas velocities of 0.2. m/s and 0.4. m/s. For particle diameters of 880 and 351. μm, the predicted characteristic times for solid dispersion were 0.14. s and 0.15. s, respectively, while characteristic times for solid diffusivity were 1.68. ms and 0.75. ms in the same... 

    Advantage of applying OSC to 1H NMR-based metabonomic data of celiac disease

    , Article International Journal of Endocrinology and Metabolism ; Volume 10, Issue 3 , 2012 , Pages 548-552 ; 1726913X (ISSN) Rezaei Tavirani, M ; Fathi, F ; Darvizeh, F ; Zali, M. R ; Nejad, M. R ; Rostami, K ; Tafazzoli, M ; oskouie, A. A ; Mortazavi Tabatabaei, S. A ; Sharif University of Technology
    Background: Celiac disease (CD) is a disorder associated with body reaction to gluten. After the gluten intake, an immune reaction against the protein occurs and damages villi of small intestine in celiac patients gradually. Objectives: The OSC, a filtering method for minimization of inter- and intra-spectrom-eter variations that influence on data acquisition, was applied to biofluid NMR data of CD patients. Patients and Methods: In this study, metabolites of total 56 serum samples from 12 CD patients, 15 CD patients taking gluten-free diet (GFD), and 29 healthy cases were analyzed using nuclear magnetic resonance (NMR) and associated theoretical analysis. Employ-ing ProMetab (version... 

    A new method for assessing domino effect in chemical process industry

    , Article Journal of Hazardous Materials ; Volume 182, Issue 1-3 , 2010 , Pages 416-426 ; 03043894 (ISSN) Abdolhamidzadeh, B ; Abbasi, T ; Rashtchian, D ; Abbasi, S. A ; Sharif University of Technology
    A new methodology is presented with which the likely impact of accident in one process unit of an industry on other process units can be forecast and assessed. The methodology is based on Monte Carlo Simulation and overcomes the limitations of analytical methods, used hitherto, which were inherently limited in their ability to handle the uncertainty and the complexity associated with domino effect phenomena. The methodology has been validated and its applicability has been demonstrated with two case studies  

    Quantitative structure-activity relationship study of serotonin (5-HT7) receptor inhibitors using modified ant colony algorithm and adaptive neuro-fuzzy interference system (ANFIS)

    , Article European Journal of Medicinal Chemistry ; Volume 44, Issue 4 , 2009 , Pages 1463-1470 ; 02235234 (ISSN) Jalali Heravi, M ; Asadollahi Baboli, M ; Sharif University of Technology
    Quantitative structure-activity relationship (QSAR) approach was carried out for the prediction of inhibitory activity of some novel quinazolinone derivatives on serotonin (5-HT7) using modified ant colony (ACO) method and adaptive neuro-fuzzy interference system (ANFIS) combined with shuffling cross-validation technique. A modified ACO algorithm is utilized to select the most important variables in QSAR modeling and then these variables were used as inputs of ANFIS to predict 5-HT7 receptor binding activities of quinazolinone derivatives. The best descriptors describing the inhibition mechanism are Qmax, Se, Hy, PJI3 and DELS which are among electronic, constitutional, geometric and... 

    Determination of fentanyl in human plasma by head-space solid-phase microextraction and gas chromatography-mass spectrometry

    , Article Journal of Pharmaceutical and Biomedical Analysis ; Volume 43, Issue 5 , 2007 , Pages 1763-1768 ; 07317085 (ISSN) Bagheri, H ; Es-haghi, A ; Khalilian, F ; Rouini, M. R ; Sharif University of Technology
    A head-space solid-phase microextraction (HS-SPME) method coupled to GC-MS was developed to extract fentanyl from human plasma. The protein binding was reduced by acidification and, eventually, the sample was deproteinized with trichloroacetic acid. The parameters influencing adsorption (extraction time, temperature, pH and salt addition) and desorption (desorption time and temperature) of the analyte on the fibre were investigated and validated for method development. The developed method proved to be rapid, simple, easy and inexpensive and offers high sensitivity and reproducibility. Linear range was obtained from 0.1 ng/ml to 2 μg/ml. The limit of detection was 0.03 ng/ml while an... 

    On-fiber standardization technique for solid-coated solid-phase microextraction

    , Article Analytical Chemistry ; Volume 79, Issue 3 , 2007 , Pages 1221-1230 ; 00032700 (ISSN) Zhou, S. N ; Zhang, X ; Ouyang, G ; Es-haghi, A ; Pawliszyn, J ; Sharif University of Technology
    The on-fiber standardization technique for solid-coated solid-phase microextraction (SPME) was studied, and a theoretical model is proposed for the isotropic behavior of adsorption and desorption, based on Fick's law of diffusion and the Langmuir model. The isotropy of the adsorption and desorption of analytes onto and from the surface of porous solid SPME fiber was validated with the use of a commercially available fiber, a 50-μm Carbowax/ templated resin for carbamate pesticide analysis in various sample matrixes, and a self-made polypyrrole fiber for diazepam analysis in blood samples. Time constants were comparable for the adsorption and desorption processes. Equilibrium constants and... 

    Design of a marker-based human motion tracking system

    , Article Biomedical Signal Processing and Control ; Volume 2, Issue 1 , 2007 , Pages 59-67 ; 17468094 (ISSN) Kolahi, A ; Hoviattalab, M ; Rezaeian, T ; Alizadeh, M ; Bostan, M ; Mokhtarzadeh, H ; Sharif University of Technology
    In this paper a complete design of a high speed optical motion analyzer system has been described. The main core of the image processing unit has been implemented by the differential algorithm procedure. Some intelligent and conservative procedures that facilitate the search algorithm have also been proposed and implemented for the processing of human motions. Moreover, an optimized modified direct linear transformation (MDLT) method has been used to reconstruct 3D markers positions which are used for deriving kinematic characteristics of the motion. Consequently, a set of complete tests using some simple mechanical devices were conducted to verify the system outputs. Considering the system... 

    Three-dimensional simulation of urine concentrating mechanism in a functional unit of rat outer medulla. I. Model structure and base case results

    , Article Mathematical Biosciences ; Vol. 258 , 2014 , pp. 44-56 ; ISSN: 00255564 Sohrabi, S ; Saidi, M. S ; Saadatmand, M ; Banazadeh, M. H ; Firoozabadi, B ; Sharif University of Technology
    The urine formation and excretion system have long been of interest for mathematicians and physiologists to elucidate the obscurities within the process happens in renal tissue. In this study, a novel three-dimensional approach is utilized for modeling the urine concentrating mechanism in rat renal outer medulla which is essentially focused on demonstrating the significance of tubule's architecture revealed in anatomic studies and physiological literature. Since nephrons and vasculatures work interdependently through a highly structured arrangement in outer medulla which is dominated by vascular bundles, a detailed functional unit is proposed based on this specific configuration.... 

    A bio-inspired modular hierarchical structure to plan the sit-to-stand transfer under varying environmental conditions

    , Article Neurocomputing ; Volume 118 , 2013 , Pages 311-321 ; 09252312 (ISSN) Sadeghi, M ; Emadi Andani, M ; Parnianpour, M ; Fattah, A ; Sharif University of Technology
    Human motion planning studies are of considerable importance in producing human-like trajectories for various industrial or clinical applications (e.g. assistive robots). In this case, the capability of Central Nervous System (CNS) in generating a large repertoire of actions can be inspirational to develop more efficient motion planning approaches. Here, inspired by structural and functional modularity in the CNS, a novel modular and hierarchical model is developed to plan the sit-to-stand (STS) transfer under varying environmental conditions. In this model, the planning process is distributed among several functionally simple modules. The cooperation of modules enables the model to plan the... 

    Discovering dominant pathways and signal-response relationships in signaling networks through nonparametric approaches

    , Article Genomics ; Volume 102, Issue 4 , October , 2013 , Pages 195-201 ; 08887543 (ISSN) Nassiri, I ; Masoudi Nejad, A ; Jalili, M ; Moeini, A ; Sharif University of Technology
    A signaling pathway is a sequence of proteins and passenger molecules that transmits information from the cell surface to target molecules. Understanding signal transduction process requires detailed description of the involved pathways. Several methods and tools resolved this problem by incorporating genomic and proteomic data. However, the difficulty of obtaining prior knowledge of complex signaling networks limited the applicability of these tools. In this study, based on the simulation of signal flow in signaling network, we introduce a method for determining dominant pathways and signal response to stimulations. The model uses topology-weighted transit compartment approach and comprises... 

    Dynamic responses of intervertebral disc during static creep and dynamic cyclic loading: A parametric Poroelastic finite element analysis

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 25, Issue 1 , 2013 ; 10162372 (ISSN) Nikkhoo, M ; Haghpanahi, M ; Parnianpour, M ; Wang, J. L ; Sharif University of Technology
    Low back pain is a common reason for activity limitation in people younger than 45 years old, and was proved to be associated with heavy physical works, repetitive lifting, impact, stationary work postures and vibrations. The study of load transferring and the loading condition encountered in spinal column can be simulated by finite element models. The intervertebral disc is a structure composed of a porous material. Many physical models were developed to simulate this phenomenon. The confounding effects of poroelastic properties and loading conditions on disc mechanical responses are, nevertheless, not cleared yet. The objective of this study was to develop an axisymmetric poroelastic... 

    Hydrodynamic characteristics of gas-solid tapered fluidized beds: Experimental studies and empirical models

    , Article Powder Technology ; Volume 283 , October , 2015 , Pages 355-367 ; 00325910 (ISSN) Rasteh, M ; Farhadi, F ; Bahramian, A ; Sharif University of Technology
    Elsevier  2015
    Understanding the hydrodynamic behavior of tapered fluidized beds is essential for accurate design and better operation in these fluid-solid contactors. Minimum fluidization velocity, minimum velocity of full fluidization, maximum pressure drop and bed expansion ratio are more important hydrodynamic characteristics in tapered fluidized beds. In this study, based on experimental data, dimensional analysis has been used to develop dimensionless correlations for predicting hydrodynamic characteristics of Geldart B particles in tapered fluidized bed. The effects of bed geometry, static bed height, particle density, size, and sphericity and also interparticle forces on hydrodynamic behavior of... 

    Micromechanics and constitutive modeling of connective soft tissues

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 60 , 2016 , Pages 157-176 ; 17516161 (ISSN) Fallah, A ; Ahmadian, M. T ; Firozbakhsh, K ; Aghdam, M. M ; Sharif University of Technology
    Elsevier Ltd 
    In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical... 

    Shuffling multivariate adaptive regression splines and adaptive neuro-fuzzy inference system as tools for QSAR study of SARS inhibitors

    , Article Journal of Pharmaceutical and Biomedical Analysis ; Volume 50, Issue 5 , 2009 , Pages 853-860 ; 07317085 (ISSN) Jalali Heravi, M ; Asadollahi Baboli, M ; Mani Varnosfaderani, A ; Sharif University of Technology
    In this work, the inhibitory activity of pyridine N-oxide derivatives against human severe acute respiratory syndrome (SARS) is predicted in terms of quantitative structure-activity relationship (QSAR) models. These models were developed with the aid of multivariate adaptive regression spline (MARS) and adaptive neuro-fuzzy inference system (ANFIS) combined with shuffling cross-validation technique. A shuffling MARS algorithm is utilized to select the most important variables in QSAR modeling and then these variables were used as inputs of ANFIS to predict SARS inhibitory activities of pyridine N-oxide derivatives. A data set of 119 drug-like compounds was coded with over hundred calculated... 

    Simulation of the effects of oxygen carriers and scaffold geometry on oxygen distribution and cell growth in a channeled scaffold for engineering myocardium

    , Article Mathematical Biosciences ; Volume 294 , 2017 , Pages 160-171 ; 00255564 (ISSN) Zehi Mofrad, A ; Mashayekhan, S ; Bastani, D ; Sharif University of Technology
    This study proposes a mathematical model to evaluate the impact of oxygen carriers and scaffold geometry on oxygen distribution and cell growth in a 3D cardiac construct using computational fluid dynamics (CFD). Flow equations, oxygen balance equation and cell balance equation were solved using special initial and boundary conditions. The modeling results revealed that 55% increase in cardiac cell density occurred by using 6.4% perfluorocarbon oxygen carrier (PFC) compared to pure culture medium without PFC supplementation. Moreover, the effects of the scaffold geometry on cell density were examined by changing the channel numbers and the construct length. A 30% increase in the average cells...