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31.
32.
Development of models for prediction of the antioxidant activity of derivatives of natural compounds
Antioxidants are important for maintaining the appropriate balance between oxidizing and reducing species in the body and thus preventing oxidative stress. Many natural compounds are being screened for their possible antioxidant activity. It was found that a mushroom pigment Norbadione A, which is a pulvinic acid derivative, shows an antioxidant activity; the same was found for other pulvinic acid derivatives and structurally related coumarines. Based on the results of in vitro studies performed on these compounds as a part of this study quantitative structure–activity relationship (QSAR) predictive models were constructed using multiple linear regression, counter-propagation artificial neural networks and support vector regression (SVR). The models have been developed in accordance with current QSAR guidelines, including the assessment of the models applicability domains. A new approach for the graphical evaluation of the applicability domain for SVR models is suggested. The developed models show sufficient predictive abilities for the screening of virtual libraries for new potential antioxidants. 相似文献
33.
Proteomic analysis of cellular soluble proteins from human bronchial smooth muscle cells by combining nondenaturing micro 2DE and quantitative LC‐MS/MS. 2. Similarity search between protein maps for the analysis of protein complexes 下载免费PDF全文
Human bronchial smooth muscle cell soluble proteins were analyzed by a combined method of nondenaturing micro 2DE, grid gel‐cutting, and quantitative LC‐MS/MS and a native protein map was prepared for each of the identified 4323 proteins [1]. A method to evaluate the degree of similarity between the protein maps was developed since we expected the proteins comprising a protein complex would be separated together under nondenaturing conditions. The following procedure was employed using Excel macros; (i) maps that have three or more squares with protein quantity data were selected (2328 maps), (ii) within each map, the quantity values of the squares were normalized setting the highest value to be 1.0, (iii) in comparing a map with another map, the smaller normalized quantity in two corresponding squares was taken and summed throughout the map to give an “overlap score,” (iv) each map was compared against all the 2328 maps and the largest overlap score, obtained when a map was compared with itself, was set to be 1.0 thus providing 2328 “overlap factors,” (v) step (iv) was repeated for all maps providing 2328 × 2328 matrix of overlap factors. From the matrix, protein pairs that showed overlap factors above 0.65 from both protein sides were selected (431 protein pairs). Each protein pair was searched in a database (UniProtKB) on complex formation and 301 protein pairs, which comprise 35 protein complexes, were found to be documented. These results demonstrated that native protein maps and their similarity search would enable simultaneous analysis of multiple protein complexes in cells. 相似文献
34.
Cover Picture: Velocity of a Molecule Evaporated from a Water Nanodroplet: Maxwell–Boltzmann Statistics versus Non‐Ergodic Events (Angew. Chem. Int. Ed. 49/2015) 下载免费PDF全文
Assist. Prof. Dr. Hassan Abdoul‐Carime Francis Berthias Dr. Linda Feketeová Dr. Mathieu Marciante Dr. Florent Calvo Dr. Valérian Forquet Prof. Dr. Henry Chermette Dr. Bernadette Farizon Prof. Dr. Michel Farizon Prof. Dr. Tilmann D. Märk 《Angewandte Chemie (International ed. in English)》2015,54(49):14587-14587
35.
Studies on Bifurcation and Chaos of a String-Beam Coupled System with Two Degrees-of-Freedom 总被引:1,自引:0,他引:1
In this paper, research on nonlinear dynamic behavior of a string-beam coupled system subjected to parametric and external
excitations is presented. The governing equations of motion are obtained for the nonlinear transverse vibrations of the string-beam
coupled system. The Galerkin's method is employed to simplify the governing equations to a set of ordinary differential equations
with two degrees-of-freedom. The case of 1:2 internal resonance between the modes of the beam and string, principal parametric
resonance for the beam, and primary resonance for the string is considered. The method of multiple scales is utilized to analyze
the nonlinear responses of the string-beam coupled system. Based on the averaged equation obtained here, the techniques of
phase portrait, waveform, and Poincare map are applied to analyze the periodic and chaotic motions. It is found from numerical
simulations that there are obvious jumping phenomena in the resonant response–frequency curves. It is indicated from the phase
portrait and Poincare map that period-4, period-2, and periodic solutions and chaotic motions occur in the transverse nonlinear
vibrations of the string-beam coupled system under certain conditions.
An erratum to this article is available at . 相似文献
36.
The existence of Smale horseshoes for a certain discretized perturbed nonlinear Schroedinger(NLS) equations was established by using n-dimensional versions of the Conley-Moser conditions. As a result, the discretized perturbed NLS system is shown to possess an invariant set Λ on which the dynamics is topologically conjugate to a shift on four symbols. 相似文献
37.
2000MathematicsSubjectClassification:35Q Introduction ContinueRef.[1],inthispart,weapplythegeneralizedConley Moserconditions[2]toshowtheexistenceofSmalehorseshoesinbelowthediscreteNLSsystems(1).Considerthefollowingn particle(any2相似文献
38.
等达因图象的自动采集与识别 总被引:1,自引:0,他引:1
文中提出了一种机机械扫描系统.小功率激光器、图象板、相移元件、微机和程序软件组成的等达因图象自动采集与处理系统,用灰度值比较的思想实现了等达因图象的跟踪采集。提出了四幅图象相移法实现等达因图象的自动识别。系统能快速、实时、精确和全自动地实现等达因图象的记录和分析。给出与物体内各点应力状态一一对应的位相图。并用来研究了其他实验方法困难的局部三维效应问题。 相似文献
39.
Martin Kummer Richard C. Churchill 《Journal of Dynamics and Differential Equations》1997,9(2):249-268
This paper presents a new derivation of the twist mapping in the planar restricted problem. It differs from other treatments in the use of a novel canonical transformation which allows for the utilization of symplectic reduction techniques. 相似文献
40.
This work is an investigation on the roots of chaotic attitudinal motion in a class of asymmetrical gyrostat satellites. The result shows that for a class of Kelvin type gyrostat satellite, there is an equivalent rigid spinning satellite with the same attitude dynamics. Finding some constants of motion and eliminating the cyclic coordinates, the rotational kinetic energy is changed to a quadratic form and using Jordan canonical form of the associated inertia tensor and transforming the coordinate system, the Hamiltonian has been changed to those of a rigid satellite. The Hamiltonian has been split into integrable and non-integrable parts. Using Deprit canonical transformation and Andoyer variables the integrable part has been reduced to a one-dimensional form. The reduced Hamiltonian shows that the regular dynamics of the satellite can be chaotic, under the influence of gravitational effects. To demonstrate various attitudinal dynamics of the satellite, a second-order Poincaré map is employed. This research shows firstly, that the attitudinal dynamics of Kelvin type gyrostat satellites and rigid satellites follow the same dynamical patterns, secondly, for non-linear analysis of dynamics of gyrostat satellite based on the perturbation methods, there is a preferable form for Hamiltonian of the system in the near-integrable fashion and thirdly the chaotic motion is originated from the gravitational field effects that can be suppressed by increasing the attitudinal energy of the satellite in comparison with the translational energy. 相似文献