An Isothermal Titration Microcalorimetric Study on the Interaction ofThree Water-Soluble Porphyrins with Histone H2B

A.K.Bordbar,A.R.Ghaderi,E.Safaei,S.Tangestaninejad,A.Eslami,A.A.Saboury,A.A.Moosavi-Movahedi 대한화학회 2003 Bulletin of the Korean Chemical Society Vol.24 No.5

A discrete fracture network model for geometrical modeling of cylindrically folded rock layers

Fereshtenejad, S.,Afshari, M.K.,Bafghi, A.Y.,Laderian, A.,Safaei, H.,Song, J.J. Elsevier Pub. Co 2016 Engineering geology Vol.215 No.-

Geometrical characterization of discontinuities is a crucial step in determining the mechanical and hydraulic properties of rock masses. Discrete fracture network models are developed to model the geometric properties of discontinuities using the statistical distributions of these properties measured from core logging and outcrop mapping analyses. Among all of the discontinuity properties, shape is the most controversial. In previous discrete fracture network models, discontinuities have been considered to be limited or unlimited planes, but in reality curved discontinuities are also observed. Based on previous research, the planar assumption in rocks containing curved discontinuities leads to considerable errors in subsequent analyses. Curved discontinuities and reasons for their formation have not yet been specifically classified. However, it is obvious that there are several reasons for the creation of these types of discontinuities. Folding is the most common factor responsible for the generation of curved discontinuities. In this paper, a practical 3D geometric method is proposed to model folded rock layers. The method relies on Fourier analysis to model the folded layer and generates suitable input data for subsequent mechanical analysis via a purposely developed MATLAB script named RocFold. The applicability of the proposed model and script is tested by using an example of a typical folded structure in the Anjire mine, Iran.

An Isothermal Titration Microcalorimetric Study on the Interaction of Three Water-Soluble Porphyrins with Histone H₂B

Bordbar, A.K.,Ghaderi, A.R.,Safaei, E.,Tangestaninejad, S.,Eslami, A.,Saboury, A.A.,Moosavi Movahedi, A.A. Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.5

In the present work, the interaction of three water soluble porphyrins, tetra(p-trimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyle) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (p-sulphonato phenyl) porphinato acetate (MnTSPP) as a metal porphyrin, with histone H₂B have been studied by isothermal titration microcalorimetry at 8 mM phosphate buffer, pH 6.8 and 27 °C. The values of binding constant, entropy, enthalpy and Gibbs free energy changes for binding of the first MnTSPP, and first and second TSPP and TAPP molecules were estimated from microcalorimetric data analysis. The results represent that the process is both entropy and enthalpy driven and histone induces self-aggregation of the porphyrins. The results indicate that both columbic and hydrophobic interactions act as self-aggregation driving forces for the formation of aggregates around histone.

Tetrabromocatecholato Mn(III) complexes of bis(phenol) diamine ligands as models for enzyme-substrate adducts of catechol dioxygenases

Safaei, E.,Hajikhanmirzaei, L.,Alavi, S.,Lee, Y.I.,Wojtczak, A.,Jaglicic, Z. Pergamon Press 2016 Polyhedron Vol.118 No.-

<P>Two mononuclear manganese(III) complexes of bis(phenol) diamine ligands (H2LNEX) and 2,3,4,5-tetrabromocatechol (TBC), MnLNEX(TBC), were synthesized as models for enzyme-catechol adducts of the intradiol Fe-dependent catechol dioxygenases. X-ray analysis of the complexes has revealed that the manganese center in the model compounds has a distorted octahedral coordination sphere and is surrounded by the L-NEX ligand and two oxygen atoms of TBC. The phenolate moieties of MnLNEX(TBC) were electrochemically oxidized to phenoxyl radicals. Consistent with the electrochemical results, quantum chemical calculations showed that the HOMO and LUMO levels on both complexes are on the phenolate moieties. The paramagnetic properties of the manganese(III) center of the complexes have been investigated by magnetic susceptibility measurements. H2LNEX/MnCl2 showed quite good enzyme-mimicking reactivity. It utilized molecular oxygen in carrying out the cleavage of di-tert-butyl catechol at room temperature. To the best of our knowledge this is the second report where a manganese complex can perform oxygenase and not oxidase activity. (C) 2016 Elsevier Ltd. All rights reserved.</P>

TEMPO-mediated aerobic oxidation of alcohols using copper(II) complex of bis(phenol) di-amine ligand as biomimetic model for Galactose oxidase enzyme

Safaei, E.,Hajikhanmirzaei, L.,Karimi, B.,Wojtczak, A.,Cotic, P.,Lee, Y.I. Pergamon Press 2016 Polyhedron Vol.106 No.-

<P>Mononuclear copper complexes of four-dentate N2O2 bis(phenol) diamine ligands (H2LNEX X: C and OB in which C and OB are chloro and tert-butyl-methoxy substituents on phenol groups) have been synthesized and characterized by IR, UV-Vis, single crystal X-ray diffraction, magnetic susceptibility studies and cyclic voltammetry techniques. The CuLNEX complexes show the square pyramid geometry of the coordination sphere with the copper centers surrounded by two nitrogen and oxygen atoms from the coordinating ligand and an axially bound water molecule. The effective magnetic moments of 1.7 and 1.8 BM confirm a monomer complex with copper(II) center. Electrochemical oxidation of these complexes yielded the corresponding Cu(II)-phenoxyl radical species. In addition, CuLNEX complexes, have shown efficient catalytic activities for TEMPO-mediated oxidation of a set of alcohols to the corresponding aldehydes in the presence of molecular oxygen as oxidant at room temperature. (C) 2015 Elsevier Ltd. All rights reserved.</P>

The application of nonlocal elasticity to determine vibrational behavior of FG nanoplates

A. M. Fattahi,Babak Safaei,Elham Moaddab 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.2

Nonlocal elasticity and Reddy plant theory are used to study the vibration response of functionally graded (FG) nanoplates resting on two parameters elastic medium called Pasternak foundation. Nonlocal higher order theory accounts for the effects of both scale and the effect of transverse shear deformation, which becomes significant where stocky and short nanoplates are concerned. It is assumed that the properties of FG nanoplate follow a power law through the thickness. In addition, Poisson’s ratio is assumed to be constant in this model. Both Winkler-type and Pasternak-type foundation models are employed to simulate the interaction of nanoplate with surrounding elastic medium. Using Hamilton’s principle, size-dependent governing differential equations of motion and corresponding boundary conditions are derived. A differential quadrature approach is being utilized to discretize the model and obtain numerical solutions for various boundary conditions. The model is validated by comparing the results with other published results.

Experimental studies on elastic properties of high density polyethylene-multi walled carbon nanotube nanocomposites

A. M. Fattahi,Babak Safaei,Zhaoye Qin,Fulei Chu 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.2

The effect of nanoparticle volume fraction on the elastic properties of a polymer-based nanocomposite was experimentally investigated and the obtained results were compared with various existing theoretical models. The nanocomposite was consisted of high density polyethylene (HDPE) as polymeric matrix and 0, 0.5, 1 and 1.5 wt.% multi walled carbon nanotubes (MWCNTs) prepared using twin screw extruder and injection molding technique. Nanocomposite samples were molded in injection apparatus according to ASTM-D638 standard. Therefore, in addition to morphological investigations of the samples, tensile tests at ambient temperature were performed on each sample and stress-strain plots, elastic moduli, Poisson’s ratios, and strain energies of volume units were extracted from primary strain test results. Tensile test results demonstrated that 1 wt.% nanoparticles presented the best reinforcement behavior in HDPE-MWCNT nanocomposites. Due to the agglomeration of nanoparticles at above 1 wt.%, Young’s modulus, yielding stress, fracture stress, and fracture energy were decreased and Poisson’s ratio and failure strain were increased.

Synthesis and characterization of an iron(III) complex of an ethylenediamine derivative of an aminophenol ligand in relevance to catechol dioxygenase active site

Safaei, E.,Naghdi, N.,Jaglicic, Z.,Pevec, A.,Lee, Y.I. Pergamon Press 2017 Polyhedron Vol.122 No.-

<P>An ethylene diamine derivative of a bis(phenol)diamine ligand (H2L) was synthesized via the Mannich reaction and subsequent ring cleavage of the produced imidazoline ring (H2LIm), and then it was characterized by H-1 NMR and IR spectroscopies and CHN analysis. The iron(III) complex (FeLCI) of this ligand was synthesized and characterized by IR, UV-Vis, X-ray and magnetic susceptibility studies. X-ray analysis reveals that in FeLCl the iron(III) center has a distorted square pyramidal coordination sphere and is surrounded by a chlorine atom, two amine nitrogen and two phenolate oxygen atoms of the ligand. Variable-temperature magnetic susceptibility measurements indicate that FeLCI is a paramagnetic high spin iron(III) complex. It shows weak antiferromagnetic interactions through N-H center dot center dot center dot Cl intermolecular interactions. The ligand-centered electrochemical oxidation of this complex, due to the oxidation of phenolate group to phenoxyl radicals, as well as the electrochemical metal-centered reduction of the ferric ion to the ferrous ion were investigated. In addition, the efficient cleavage by oxygenation of 3,5-di-tertbutyl-catechol with FeLCI in the presence of dioxygen was observed. (C) 2016 Elsevier Ltd. All rights reserved.</P>

MATLAB-BASED MODELING, SIMULATION AND DESIGN PACKAGE FOR ELETRIC, HYDRAULIC AND FLYWHEEL HYBRID POWERTRAINS OF A CITY BUS

M. ESFAHANIAN,A. SAFAEI,H. NEHZATI,V. ESFAHANIAN,M. M. TEHRANI 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.6

In this paper a package for designing, modelling and simulation of three hybrid powertrains are presented. These powertrains are Electric hybrid, Hydraulic hybrid and Flywheel hybrid. The differences among the proposed hybridpowertrains include the energy storage system components, the secondary power converter and also the powertrainconfiguration. The O457 city bus is considered as the benchmark vehicle. At first, the design process for each hybridpowertrain which is based on the power requirements of the bus in any driving condition is presented. Then, the powertrainsmodelling using MATLAB/Simulink as a powerful simulating tool is presented. The models are feed-forward and resemblethe real world driving conditions. Each model has the blocks for the main components of the corresponding propulsion system. The most important stage in the modeling process is implementing of the components efficiency in each powertrain. Moreover, there is a block in each hybrid powertrain model for the energy management. Finally, the simulation results forcomparing the usefulness of the hybrid powertrains are presented. The results indicate that the electric hybrid powertrain hasthe most effect on reducing the bus fuel consumption. But regarding the fabrication expenses and manufacturing complexity,the hydraulic hybrid powertrain is recommended.

Numerical study on the structural performance of corrugated low yield point steel plate shear walls with circular openings

Mahdi Shariati,Shervin Safaei Faegh,Peyman Mehrabi,Seyedmasoud Bahavarnia,Yousef Zandi,Davood Rezaee Masoom,Ali Toghroli,Nguyen-Thoi Trung,Musab N.A. Salih 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.4

Corrugated steel plate shear wall (CSPSW) as an innovative lateral load resisting system provides various advantages in comparison with the flat steel plate shear wall, including remarkable in-plane and out-of-plane stiffnesses and stability, greater elastic shear buckling stress, increasing the amount of cumulative dissipated energy and maintaining efficiency even in large story drifts. Employment of low yield point (LYP) steel web plate in steel shear walls can dramatically improve their structural performance and prevent early stage instability of the panels. This paper presents a comprehensive structural performance assessment of corrugated low yield point steel plate shear walls having circular openings located in different positions. Accordingly, following experimental verification of CSPSW finite element models, several trapezoidally horizontal CSPSW (H-CSPSW) models having LYP steel web plates as well as circular openings (for ducts) perforated in various locations have been developed to explore their hysteresis behavior, cumulative dissipated energy, lateral stiffness, and ultimate strength under cyclic loading. Obtained results reveal that the rehabilitation of damaged steel shear walls using corrugated LYP steel web plate can enhance their structural performance. Furthermore, choosing a suitable location for the circular opening regarding the design purpose paves the way for the achievement of the shear wall's optimal performance.