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51.
Satyanarayanaraju Sagi Bharathi Avula Yan‐Hong Wang Jianping Zhao Ikhlas A. Khan 《Journal of separation science》2014,37(19):2797-2804
A simple and rapid high‐performance thin‐layer chromatographic method was developed for the separation and determination of six flavonoids (rutin, luteolin‐7‐O‐β‐glucoside, chamaemeloside, apigenin‐7‐O‐β‐glucoside, luteolin, apigenin) and one coumarin, umbelliferone from chamomile plant samples and dietary supplements. The separation was achieved on amino silica stationary phase using dichloromethane/acetonitrile/ethyl formate/glacial acetic acid/formic acid (11:2.5:3:1.25:1.25 v/v/v/v/v) as the mobile phase. The quantitation of each compound was carried out using densitometric reflection/absorption mode at their respective absorbance maxima after postchromatographic derivatization using natural products reagent (1% w/v methanolic solution of diphenylboric acid‐β‐ethylamino ester). The method was validated for specificity, limits of detection and quantification, precision (intra‐ and interday) and accuracy. The limits of detection and quantification were found to be in the range from 6–18 and 16–55 ng/band for six flavonoids and one coumarin, respectively. The intra‐ and interday precision was found to be <5% RSD and recovery of all the compounds was >90%. The data acquired from high‐performance thin‐layer chromatography was processed by principal component analysis using XLSTAT statistical software. Application of principal component analysis and agglomerative hierarchial clustering was successfully able to differentiate two chamomiles (German and Roman) and Chrysanthemum. 相似文献
52.
Ukrainian Mathematical Journal - We study the problems of uniqueness of difference-differential polynomials of finite-order meromorphic functions sharing a small function (ignoring multiplicities)... 相似文献
53.
A. M. Mathai 《Studies in Applied Mathematics》1989,80(1):75-93
The gravitational clustering of a multicomponent medium in an expanding universe has been considered by many authors in recent years. The system of differential equations associated with such a multicomponent medium is generalized in this article by incorporating arbitrary parameters. Explicit analytic solutions of this generalized system are given for various situations. Physical interpretations of the solutions are not considered, but the various solutions of physical problems obtained by various authors can be seen to be special cases of the general solutions given in this article. 相似文献
54.
Peter Bouwknegt Alan L. Carey Varghese Mathai Michael K. Murray Danny Stevenson 《Communications in Mathematical Physics》2002,228(1):17-49
In this note we introduce the notion of bundle gerbe K-theory and investigate the relation to twisted K-theory. We provide some examples. Possible applications of bundle gerbe K-theory to the classification of K-brane charges in nontrivial backgrounds are briefly discussed.
Received: 29 June 2001 / Accepted: 15 October 2001 相似文献
55.
Vijay Nair Sreeletha B. Panicker Sindhu Mathai 《Research on Chemical Intermediates》2003,29(2):227-231
The bromination of cyclopropanes using potassium bromide and cerium(IV) ammonium nitrate (CAN) in a two-phase system consisting of water and dichloromethane affording 1,3-dibromides in excellent yields is reported. 相似文献
56.
Dirichlet integrals and the associated Dirichlet statistical densities are widely used in various areas. Generalizations of
Dirichlet integrals and Dirichlet models to matrix-variate cases, when the matrices are real symmetric positive definite or
hermitian positive definite, are available [4]. Real scalar variables case of the Dirichlet models are generalized in various
directions. One such generalization of the type-2 or inverted Dirichlet is looked into in this article. Matrix-variate analogue,
when the matrices are hermitian positive definite, are worked out along with some properties which are mathematically and
statistically interesting. 相似文献
57.
58.
A. M. Mathai 《Mathematische Nachrichten》1978,84(1):171-177
A number of integrals of scalar variables are extended to the case of matrix variables. Functions where the argument is a positive definite symmetric matrix are considered in this article. With the help of a generalized matrix transform a number of results are derived which are extensions of the corresponding results in the univariate cases. 相似文献
59.
We extend and apply a rigorous renormalisation group method to study critical correlation functions, on the 4-dimensional lattice \({{{\mathbb{Z}}}^{4}}\), for the weakly coupled n-component \({|\varphi|^{4}}\) spin model for all \({n \ge 1}\), and for the continuous-time weakly self-avoiding walk. For the \({|\varphi|^{4}}\) model, we prove that the critical two-point function has |x|?2 (Gaussian) decay asymptotically, for \({n \ge 1}\). We also determine the asymptotic decay of the critical correlations of the squares of components of \({\varphi}\), including the logarithmic corrections to Gaussian scaling, for \({n \ge 1}\). The above extends previously known results for n = 1 to all \({n \ge 1}\), and also observes new phenomena for n > 1, all with a new method of proof. For the continuous-time weakly self-avoiding walk, we determine the decay of the critical generating function for the “watermelon” network consisting of p weakly mutually- and self-avoiding walks, for all \({p \ge 1}\), including the logarithmic corrections. This extends a previously known result for p = 1, for which there is no logarithmic correction, to a much more general setting. In addition, for both models, we study the approach to the critical point and prove the existence of logarithmic corrections to scaling for certain correlation functions. Our method gives a rigorous analysis of the weakly self-avoiding walk as the n = 0 case of the \({|\varphi|^{4}}\) model, and provides a unified treatment of both models, and of all the above results. 相似文献
60.