Izadyar M.,University of Payam Noor |
Esmaili E.,University of Payam Noor |
Harati M.,University of Windsor
Progress in Reaction Kinetics and Mechanism | Year: 2011
A density functional theoretical (DFT) study has been carried out at the B3LYP=6-31G(d) level on the gas-phase retro-ene reaction of allyl methyl amine (AMN). The results were compared with single point calculations at a high level of the theory, using the G3MP2 method. Two mechanisms for this kind of reaction are possible, one involves a six-membered cyclic transition state (TS) and the other is a multistep, free radical mechanism. Both DFT and high level calculations show that propene and imine formation are in accordance with a concerted cyclic mechanism. Natural bond orbital analysis (NBO) and atoms-inmolecule (AIM) procedures show that the reaction achieves a synchronicity value of 90%. The calculated kinetic parameters for AMN pyrolysis agree with the available experimental results. © 2011 Science Reviews 2000 Ltd.
Aghazadeh M.,University of Payam Noor |
Castro A.,University of Huelva |
Badrzadeh Z.,University of Payam Noor |
Vogt K.,ETH Zurich
Geological Magazine | Year: 2011
The petrological and geochronological study of the Cenozoic Shaivar Dagh composite intrusion in the Alborz Mountain belt (NW Iran) reveals important clues to decipher complex relations between magmatic and tectonic processes in the central sectors of the Tethyan (Alpine-Himalayan) orogenic belt. This pluton is formed by intrusion at different times of two main magmatic cycles. The older (Cycle 1) is formed by calc-alkaline silicic rocks, which range in composition from diorites to granodiorites and biotite granites, with abundant mafic microgranular enclaves. The younger cycle (Cycle 2) is formed by K-rich monzodiorite and monzonite of marked shoshonitic affinity. The latter form the larger volumes of the exposed plutonic rocks in the studied complex. Zircon geochronology (laser ablation ICP-MS analyses) gives a concordia age of 30.8 ± 2.1 Ma for the calc-alkaline rocks (Cycle 1) and a range from 23.3 ± 0.5 to 25.1 ± 0.9 Ma for the shoshonitic association (Cycle 2). Major and trace element relations strongly support distinct origins for each magmatic cycle. Rocks of Cycle 1 have all the characteristic features of active continental margins. Shoshonitic rocks (Cycle 2) define two continuous fractionation trends: one departing from a K-rich basaltic composition and the other from an intermediate, K-rich composition. A metasomatized-mantle origin for the two shoshonitic series of Cycle 2 is proposed on the basis of comparisons with experimental data. The origin of the calc-alkaline series is more controversial but it can be attributed to processes in the suprasubduction mantle wedge related to the incorporation of subducted mélanges in the form of silicic cold plumes. A time sequence can be established for the processes responsible of the generation of the two magmatic cycles: first a calc-alkaline cycle typical of active continental margins, and second a K-rich cycle formed by monzonites and monzodiorites. This sequence precludes the younger potassic magmas as precursors of the older calc-alkaline series. By contrast, the older calc-alkaline magmas may represent the metasomatic agents that modified the mantle wedge during the last stages of subduction and cooked a fertile mantle region for late potassic magmatism after continental collision. © 2011 Cambridge University Press.
Momeni L.,University of Payam Noor |
Momeni L.,Shahrekord University |
Shareghi B.,Shahrekord University |
Saboury A.A.,University of Tehran |
Farhadian S.,Shahrekord University
RSC Advances | Year: 2016
This work studied the interaction between spermine and trypsin at pH 8.0. The thermal stability of trypsin was investigated in the presence of spermine over a temperature range (from 293 K to 353 K). Additionally, the conformational change of trypsin induced by spermine was analyzed by UV-vis absorption and fluorescence spectra. The effect of spermine on trypsin activity was studied at 37 °C and pH 8.0, using Tris-HCl as a buffer. The fluorescence spectroscopy results indicated that the binding of spermine to trypsin was a spontaneous binding process. The fluorescence of trypsin was quenched by spermine through the static quenching mechanism. By increasing the concentration of spermine, the thermal stability of trypsin was increased. The quantitative analysis of CD spectra revealed some information regarding the changes in the content of the α-helix and the β-sheet of the trypsin upon binding to spermine. It was also found that by increasing the concentration of spermine, the activity of trypsin was increased. Molecular docking results also revealed the presence of one binding site with a negative value for the Gibbs free energy of the binding of spermine to trypsin. Further, the docking and fluorescence spectroscopy study revealed that van der Waals interactions and hydrogen bonds played a major role in stabilizing the complex. As a result, spermine could be considered as an activator and stabilizer for trypsin. This journal is © The Royal Society of Chemistry 2016.
Farhadian S.,Shahrekord University |
Shareghi B.,Shahrekord University |
Saboury A.A.,University of Tehran |
Momeni L.,University of Payam Noor
RSC Advances | Year: 2016
Stabilized aqueous solutions of α-chymotrypsin have a therapeutic utility in the treatment of certain forms of asthma, bronchitis, rhinitis, sinusitis, as well as certain dermatological conditions such as leg ulcers and ringworm. The aim of the present study was to investigate how lactose could influence the structure, thermal stability and the activity of α-chymotrypsin. The influence of lactose on the structure and stability of α-chymotrypsin (α-Chy) was explored using thermal stability, fluorescence spectroscopy, circular dichroism (CD) kinetic studies and molecular docking. We have calculated the thermodynamic parameters for the transition temperature (Tm), enthalpy change (ΔH°), entropy change (ΔS°) and Gibbs free energy change (ΔG°) to understand the stability of α-Chy. Lactose acted as an enhancer for the α-Chy stability, with varying efficacies and efficiencies. The results of the kinetic study displayed that the activity of α-Chy increased in the presence of lactose. The result reveals the ability of lactose to protect the native structural conformation of α-Chy. These results explicitly explain that stabilizing lactose is preferentially excluded from the surface of α-Chy, because water has a higher tendency toward favorable interactions with functional groups of α-Chy than with lactose. Fluorescence intensity changes showed static quenching during the lactose binding. The α-Chy fluorescence quenching suggested the more polar location of Trp residues. Near-UV and far-UV CD studies also proved the transfer of Trp, Phe and Tyr residues to a more flexible environment. Increasing of the α-Chy absorption in the presence of lactose was as a result of the formation of lactose-α-Chy complex. Molecular docking results revealed a negative value for the Gibbs free energy of the binding of lactose to α-Chy and the presence of one binding site. Docking study also revealed that hydrogen bond interactions dominated within the binding site. © 2016 The Royal Society of Chemistry.
Mansouri-Torshizi H.,University of Sistan and Baluchestan |
Eslami-Moghadam M.,University of Payam Noor |
Divsalar A.,University of Tehran |
Saboury A.-A.,University of Tehran
Acta Chimica Slovenica | Year: 2011
In this study two platinum(II) and palladium(II) complexes of the type [M(bpy)(pip-dtc)]NO3 (where M=Pt(II) or Pd(II), bpy=2,2'-bipyridine, pip-dtc=piperidinedithiocarbamate) were synthesized by reaction between diaquo-2,2'-bipyridine Pt(II)/Pd(II) nitrate and sodium salt of dithiocarbamate. These cationic water soluble complexes were characterized by elemental analysis, molar conductance, IR, electronic and 1H NMR spectroscopic studies. The cyclic dithiocarbamate was found to coordinate as bidentate fasion with Pt(II) or Pd(II) center. Their biological activities were tested against chronic myelogenous leukemia cell line, K562, at micromolar concentration. The obtained cytotoxic concentration (IC50) values were much lower than cisplatin. The interaction of these complexes with highly polymerized calf thymus DNA (ct-DNA) was extensively studied by means of electronic absorption, fluorescence, circular dichroism and other measurements. The experimental results, thermodynamic and binding parameters, suggested that these complexes cooperatively bind to DNA presumably via intercalation. Moreover, the tendency of the Pt(II) complex to interact with DNA was more than that of Pd(II) complex.
Sharafizadeh D.,Islamic Azad University |
Hosseini Astaraie F.S.,University of Payam Noor
Advances in Environmental Biology | Year: 2014
The main aim of this research is to study the correlation between the factors related to the entrepreneurship and job performance of experts of Department of Agricultural Extension of Golestan Province Agricultural Organization. The research methodology is survey-descriptive. The current research population includes the experts of department of agricultural extension of Golestan province agricultural organization, and they include 126 individuals. The sample size of this research was 52 individuals using Cochran formula. Random sampling was used for choosing the samples. A questionnaire was formulated in order to collect the required data and information. The face validity was studied and the necessary reformations were conducted by the use of experts' and professors' comments. Also the Cronbach's alpha for the job performance questionnaire was (α= 0.98), entrepreneurs' characteristics was (α= 0.89), entrepreneurs' capacities and abilities was (α= 0.83). Research findings showed that among all of the research variables, variables of environmental protection, opportunism, being a pioneer, need for achievement, being a leader, and tolerating ambiguity have positive and significant correlation with the job performance variable. In the results of multivariate linear regression only the opportunism had the ability of explaining 18.7% of the job performance changes. © 2013 AENSI Publisher All rights reserved.
Yoosefian M.,Kerman Graduate University of Technology |
Etminan N.,University of Tehran |
Moghani M.Z.,University of Payam noor |
Mirzaei S.,University of Payam noor |
Abbasi S.,University of Payam noor
Superlattices and Microstructures | Year: 2016
Density functional theory (DFT) studies on the interaction of hydrogen halides (HX) environmental pollutants and the boron nitride nanotubes (BNNTs) have been reported. To exploit the possibility of BNNTs as gas sensors, the adsorption of hydrogen fluoride (HF), hydrogen chloride (HCl) and hydrogen bromide (HBr) on the side wall of armchair (5,5) boron nitride nanotubes have been investigated. B3LYP/6-31G (d) level were used to analyze the structural and electronic properties of investigate sensor. The adsorption process were interpreted by highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO), quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) and molecular electrostatic potential (MEP) analysis. Topological parameters of bond critical points have been used to calculate as measure of hydrogen bond (HB) strength. Stronger binding energy, larger charge transfer and charge density illustrate that HF gas possesses chemisorbed adsorption process. The obtained results also show the strongest HB in HF/BNNT complex. We expect that results could provide helpful information for the design of new BNNTs based sensing devices. © 2016 Elsevier Ltd
PubMed | Islamic Azad University, University of Tehran, Shahrekord University and University of Payam Noor
Type: Journal Article | Journal: International journal of biological macromolecules | Year: 2016
The interaction of putrescine with bovine trypsin was investigated using steady state thermal stability, intrinsic fluorescence, UV-vis spectroscopy, far and near- UV circular dichroism and kinetic techniques, as well as molecular docking. The Stern-Volmer quenching constants for the trypsin- putrescine complex were calculated revealing that putrescine interacted with trypsin via the static fluorescence quenching. The enthalpy and entropy change values and the molecular docking technique revealed that hydrogen bonds and van der Waals forces play a major role in the binding process. Upon putrescine conjugation, the V
Nazari F.,Institute for Advanced Studies in Basic Sciences |
Doroodi Z.,University of Payam Noor
International Journal of Quantum Chemistry | Year: 2010
The structural and electronic characteristics of the M4R 4 with M = C, Si, Ge and R = H, F, Cl, OH, MgH, BH2, NH2 Li are studied by ab initio calculations based on density functional theory using the hybrid B3LYP functional and 6-311++G* basis set. The results of natural bond orbital analysis (NBO), the analysis of structural parameters (bond lengths and bond angle, dihedral angle), atoms in molecules based theory (AIM) topological parameters such as the characteristics of bond critical points (electron densities and their Laplacians) leads to the conclusion that interamolecular interaction due with OH, MgH2, and NH2 substitutions are different from other derivatives. The cyclobutadiene ring and its heavy versions display very different geometrical structures. The cations and anions of C4R4, Si 4R4, and Ge4R4 were studied to determine the effect of substitution on structure and stability. It has been shown that substitutions with ability of forming hydrogen bonds, bound to the silicon and germanium atoms are able to change the properties of the four-member rings more than the other substitutions. Comprehensive analyses of calculated NICS (nucleusindependent chemical shifts), polarizability, electrophilicity, and electron density are done. © 2009 Wiley Periodicals, Inc.
Samangan R.Z.,Gorgan University of Medical science |
Samakhosh N.S.,University of payam noor
Advances in Environmental Biology | Year: 2014
The innate appeal of religion, the religion of human history has a Twin Despite being innate, inborn tendencies of religion, as many people are suffering damagen, that Prophets of internal tension and external efforts for broad trends and ideas useful in practice no religion; The group also thought so as well in practice and are paid to deny religion. After acceptance and practice of religious propositions then turned away and became apostates and and others in the practice of religion back today to find this angle is interpreted as an aversion to religion. Arguably the most important topics in the realm of nature, escaping the religious pathology that must be stemmed, this study seeks to identify the causes of it away in all three areas that By referring to the Koran and the Hadith, such factors as: evil, corrupt environment, friends, err, the hardships of life, God's lack of leadership and as a result of the defection of three of its funding comes from. © 2014 AENSI Publisher All rights reserved.