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1.
Valery Kukhar Vladimir Solodenko Vadim Soloshonok Tamara Kasheva 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):529-532
Abstract Synthesis of enantiomeric amino phosphonic acids APA is described by using chiral auxiliary reagent or enzymatic resolution of racemic mixtures of APA phenacyl derivatives. Peptides with APA residue were obtained by application of trimethylsilyl derivatives or condensation in the presence of enzyme-papain 相似文献
2.
Tetko IV Aksenova TI Volkovich VV Kasheva TN Filipov DV Welsh WJ Livingstone DJ Villa AEP 《SAR and QSAR in environmental research》2000,11(3-4):263-280
This article presents a self-organising multilayered iterative algorithm that provides linear and non-linear polynomial regression models thus allowing the user to control the number and the power of the terms in the models. The accuracy of the algorithm is compared to the partial least squares (PLS) algorithm using fourteen data sets in quantitative-structure activity relationship studies. The calculated data show that the proposed method is able to select simple models characterized by a high prediction ability and thus provides a considerable interest in quantitative-structure activity relationship studies. The software is developed using client-server protocol (Java and C++ languages) and is available for world-wide users on the Web site of the authors. 相似文献
3.
TN Ruckmongathan 《Pramana》1999,53(1):199-212
Liquid crystal displays had a humble beginning with wrist watches in the seventies. Continued research and development in
this multi-disciplinary field have resulted in displays with increased size and complexity. After three decades of growth
in performance, LCDs now offer a formidable challenge to the cathode ray tubes (CRT).
A major contribution to the growth of LCD technology has come from the developments in addressing techniques used for driving
matrix LCDs. There are several approaches like passive matrix addressing, active matrix addressing and plasma addressing to
drive a matrix display.
Passive matrix LCD has a simple construction and uses the intrinsic non-linear characteristic of the LCD for driving. Departure
from conventional line by line addressing of a passive matrix has resulted in improved performance of the display. Orthogonal
functions have played a crucial role in the development of passive matrix addressing. Simple orthogonal functions that are
useful for driving a matrix LCD are introduced. The basics of driving several rows simultaneously (multi-line addressing)
are discussed by drawing analogies from multiplexing in communication. The impact of multi-line addressing techniques on the
performance of the passive matrix LCDs in comparison with the conventional technique will be discussed. 相似文献
4.
Tetko IV Tanchuk VY Kasheva TN Villa AE 《Journal of chemical information and computer sciences》2001,41(2):246-252
In this paper we describe an Internet Java-based technology that allows scientists to make their analytical software available worldwide. The implementation of this technology is exemplified by programs for the calculation of the lipophilicity and water solubility of chemical compounds available at http://www.lnh.unil.ch/~itetko/logp. Both these molecular properties are key parameters in quantitative structure-activity relationship studies and are used to provide invaluable information for the overall understanding of the uptake distribution, biotransformation, and elimination of a wide variety of chemicals. The compounds can be analyzed in batch or single-compound mode. The single-compound analysis offers the possibility to compare our results with several popular lipophilicity calculation methods, including CLOGP, KOWWIN, and XLOGP. The chemical compounds are analyzed according to SMILES line notation that can be prepared with the JME molecular editor of Peter Ertl. Conversion to SMILES from 56 formats is also available using the molecular structure information interchange hub developed by Pat Walters and Matt Stahl. 相似文献
5.
MAO Feng SHI YiPeng XUAN LiJun SU WeiDong & WU JieZhi State Key Laboratory for Turbulence Complex Systems College of Engineering Peking University Beijing China University of Tennessee Space Institute Tullahoma TN USA 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decompos... 相似文献
6.
V. K. Svedas E. V. Kozlova D. A. Mironenko V. P. Kukhar T. N. Kasheva V. A. Solodenko 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Penicillin acylase from E. coli (FC 3.5.1.11) was found to hydrolyse N-phenylacetylated 1-aminoalkylphosphonic acids and their esters. Enzyme preferentially converts the R-form of the substrates: the ratios of the bimolecular rate constants of penicillin acylase-catalysed hydrolysis of R-and S- forms of 1-(N-phenylacetaminol-ethylphosphonic acid and its dimethyl- and diisopropyl- esters are 58000, 2600, 1800; these derivatives were shown to have the greatest values of the catalytic constants for enzymatic hydrolysis of all known substrates of penicillin acylase: 237, 148, and 134 s; corresponding values of Michaelis constants are 3.7×10?5, 6.8×10?4, and 6.2×10?4 M. The kinetics of the enzymatic hydrolysis of 1-(N-phenylacetaminol-ethylphosphonic acid was investigated up to high degrees of conversion. The inhibition of penicillin acylase by high concentrations of the R-form of the substrate (with substrate inhibition constant 0.07 Ml and competitive inhibition by the reaction product phenylacetic acid (Ki=3.5×10?5 M) was observed. Penicillin acylase was shown to possess quite broad substrate specificity among N-acylated 1-aminoalkylphosphonic acids and was found to be capable of hydrolysing 1-(N-phenylacetaminol-substituted 2-phenylethyl-, 1-phenylmethyl- and 3-methylbutylphosphonic acids with high efficiency and enantioselectivity. 相似文献
7.
Aminoalkylphosphonic acids on heating with hexamethyldisilazane yield tris(trimethylsilyl) derivatives, which are used as amino components for the synthesis of N-acylated phosphonopeptides with free phosphonic group. These transformations proceed with complete retention of the stereoconfiguration of aminophosphonate moiety. 相似文献
8.
I V Tetko V Y Tanchuk T N Kasheva A E Villa 《Journal of chemical information and computer sciences》2001,41(6):1488-1493
The molecular weight and electrotopological E-state indices were used to estimate by Artificial Neural Networks aqueous solubility for a diverse set of 1291 organic compounds. The neural network with 33-4-1 neurons provided highly predictive results with r(2) = 0.91 and RMS = 0.62. The used parameters included several combinations of E-state indices with similar properties. The calculated results were similar to those published for these data by Huuskonen (2000). However, in the current study only E-state indices were used without need of additional indices (the molecular connectivity, shape, flexibility and indicator indices) also considered in the previous study. In addition, the present neural network contained three times less hidden neurons. Smaller neural networks and use of one homogeneous set of parameters provides a more robust model for prediction of aqueous solubility of chemical compounds. Limitations of the developed method for prediction of large compounds are discussed. The developed approach is available online at http://www.lnh.unil.ch/~itetko/logp. 相似文献
9.
I. V. Tetko T. I. Aksenova V. V. Volkovich T. N. Kasheva D. V. Filipov W. J. Welsh 《SAR and QSAR in environmental research》2013,24(3-4):263-280
Abstract This article presents a self-organising multilayered iterative algorithm that provides linear and non-linear polynomial regression models thus allowing the user to control the number and the power of the terms in the models. The accuracy of the algorithm is compared to the partial least squares (PLS) algorithm using fourteen data sets in quantitative-structure activity relationship studies. The calculated data show that the proposed method is able to select simple models characterized by a high prediction ability and thus provides a considerable interest in quantitative-structure activity relationship studies. The software is developed using client-server protocol (Java and C++ languages) and is available for world-wide users on the Web site of the authors. 相似文献
10.