排序方式: 共有36条查询结果,搜索用时 15 毫秒
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Bakhtyar Sepehri Zeinabe Hassanzadeh Raouf Ghavami 《Journal of the Iranian Chemical Society》2016,13(8):1525-1537
In the present study, we mainly focused on new synthesized 1,7-diazacarbazole derivatives (44 active molecules) as Chk1 inhibitors to build 3D-QSAR model. Comparative molecular field analysis (CoMFA) model with three principal components was developed. The relative contributions in building of CoMFA model were 64.41 % for steric field and 35.59 % for electrostatic field. R 2 values for training and test sets of CoMFA model were 0.8724 and 0.7818, respectively, and squared correlation coefficient for leave-one-out cross-validation test (q 2) was 0.6753. To improve the predictive power, a new 3D-QSAR model was developed by using radial basis function network (RBFN) and score of CoMFA interactions energy values as input variables. Scores 1, 2 and 3 were used as input variables, and a RBFN model with seven centers and spread value equal to 95 was developed to create a nonlinear 3D-QSAR model. R 2 values for training and test sets were 0.9613 and 0.8564, and q 2 for leave-one-out cross-validation test was 0.9258. Docking of all molecules to 3DX ligand binding site of Chk1 receptor indicated six interactions as pharmacological interactions between compounds and binding site of receptors. These pharmacological interactions were hydrogen bonding with LEU-15 and GLU-85 in main chain and four van der Waals interactions with LEU-15, VAL-23, TYR-86 and LEU-137 in side chain. CoMFA contour plots were used to design new inhibitors, and inhibitory activity of each compound was predicted by using CoMFA and RBFN models. 相似文献
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In this paper,we find the information loss for QCD matter in AdS black holes at LHC by extending the Gottesman and Preskill methode to AdS black holes.We calculate the information transformation from the collapsing matter to the state of outgoing Hawking radiation for both quarks and gluons.It is noticed that for finite values of quark and gluon energies,information from all emission processes experiences some degrees of loss.Possible explanation for this feature will be presented in this paper. 相似文献
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T. Ghaffary A. Sepehri M. Hasheminia M. E. Zomorrodian 《Indian Journal of Physics》2009,83(12):1691-1698
Charged particle momentum distributions are studied in the reaction e+e− → hadrons, using data collected with the AMY detector at center of mass energy of 58 GeV. The measured distributions and
derived quantities in combination with the corresponding results obtained at both lower and higher center of mass energies
are compared to QCD predictions in theoretical approach to study the energy dependence of the strong interaction, and to test
QCD as the theory describing it. To achieve this, the mean charged particle multiplicity, the charged particle momentum spectrum
and its peak position are compared with predictions of the modified-leading logarithmic approximation. In general, good agreement
is observed between the data and the above approximation in the regions where the model is expected to be valid. In addition
the strong coupling constant α
s
is determined from a fit of the QCD prediction to x
p
distribution of the Feynman scaling. When we leave α
s
as a free parameter in the fit we obtain α
s
= 0.115 ± 0.008. 相似文献
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H. Sepehri Amin R. Gholamipour F. Shahri A. Mohammadi 《Journal of magnetism and magnetic materials》2008
This paper reports structural and magnetic properties of rapidly quenched Co64Fe4Ni2B19−xSi8Cr3Alx (x=0, 1, 2, 3) amorphous ribbons prepared by the single roller melt spinning process. Thermal analysis of the ribbons shows that the replacement of B by Al causes a decrease in the crystallization temperature. Structural studies of the samples have been carried out by transmission electron microscopy and X-ray diffraction. With optimum amount of Al in the alloy, the as-cast material has better soft magnetic properties. The highest maximum permeability (3.55×105), saturation magnetization (523.7 mT) and the lowest coercivity (0.8174 A/m) were obtained in the sample with x=2. 相似文献
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Parviz Norouzi Gholam-Reza Nabi Bidhendi Mohammad Reza Ganjali Ali Sepehri Maryam Ghorbani 《Mikrochimica acta》2005,149(1-2):123-129
A novel chemiluminogenic reagent, refered to as spiro form fluorescein hydrazide, was synthesized, and its application to chemiluminescence (CL) determination of Co2+ is described. The method is based on the catalytic effect of Co2+ on the autoxidation of sulfite in basic solution to generate a series of powerful oxidative intermediates, which then oxidize colorless, nonfluoresent fluorescein hydrazide to generate strong CL emission. The CL signal is linearly related to the concentration of Co2+ in the range of 0.1–200nM with a detection limit of 0.04nM. The optimal conditions for the detection of Co2+ were evaluated, and the possible CL mechanism is discussed. The proposed method has been applied to the determination of Co2+ in pharmaceutical preparations and in soil samples. 相似文献
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Alireza Sepehri Richard Pincak Ahmed Farag Ali 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(11):250
We show that the defects of graphene, which lead to the non-equality between positive curvature of fermions with anti-parallel spins and negative curvature of fermions with parallel spins, imply an emergence of F(R) gravity. By increasing the number of atoms at each defect, the order of scalar curvature increases and the shape of F(R) gravity changes. This gravity has a direct relation with energy-momentum tensor and leads to motion of electrons in a special path and hence producing superconductivity. Also, for some special angles, parallel spins become close to each other and repel to each other. In that condition, the shape of F(R) gravity changes and electrons can’t continue to move in an initial path and return. Consequently, superconductivity disappears and one new conductivity appears in opposite direction. 相似文献
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Alireza Sepehri Mohammad Reza Setare Salvatore Capozziello 《The European Physical Journal C - Particles and Fields》2015,75(12):618
Recently, Padmanabhan (arXiv:1206.4916 [hep-th]) discussed that the difference between the number of degrees of freedom on the boundary surface and the number of degrees of freedom in a bulk region causes the accelerated expansion of the universe. The main question arising is: what is the origin of this inequality between the surface degrees of freedom and the bulk degrees of freedom? We answer this question in M-theory. In our model, first M0-branes are compactified on one circle and N D0-branes are created. Then N D0-branes join each other, grow, and form one D5-branes. Next, the D5-brane is compactified on two circles and our universe’s D3-brane, two D1-branes and some extra energies are produced. After that, one of the D1-branes, which is closer to the universe’s brane, gives its energy into it, and this leads to an increase in the difference between the numbers of degrees of freedom and the occurring inflation era. With the disappearance of this D1-brane, the number of degrees of freedom of boundary surface and bulk region become equal and inflation ends. At this stage, extra energies that are produced due to the compactification cause an expansion of the universe and deceleration epoch. Finally, another D1-brane dissolves in our universe’s brane, leads to an inequality between degrees of freedom, and there occurs a new phase of acceleration. 相似文献
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Motivated by considerable interests of Myers–Perry black holes, we employ the perturbative method to obtain a family of extremal charged rotating black hole solutions in odd dimensional Einstein–Born–Infeld-dilaton gravity. We start with an extremal Myers–Perry black hole with equal angular momenta, and then by adding the dilaton field and the nonlinear Born–Infeld electrodynamics, we find an extremal nonlinearly charged rotating black holes. The perturbative parameter is assumed to be the electric charge q and the perturbations are performed up to the third order. We then study the physical properties of these Born–Infeld-dilaton black holes. In particular, we show that the perturbative parameter, q, the dilaton coupling constant, α, and the Born–Infeld parameter, β, modify the Smarr formula and the values of the gyromagnetic ratio of the extremal charged rotating black holes. 相似文献
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