Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analy...Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analysis （HCA） were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments.展开更多
Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole comp...Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole complexes, i.e. [Ru（Mehn）4iip]^2＋ （1） （MeIm=l-methylimidazole, iip=2-（1H-imidazo-4-group）-lH-imidazo[n,5-f][1,10]phenanthroline）, [Ru（MeIm）4tip]^2＋ （2） （tip=2-（thiophene-2-group）-lH-imidazo[4,5-f] [i,10]phenanthroline）, and [Ru（Melm）42ntz]^2＋ （3） （2ntz=2-（2-nitro-l,3-thiazole-5-group）-lH-imidazo[4,5-f][1,10]phenanthroline）, were car- ried out using the density functional theory （DFT）. The electronic structures of these Ru（II） complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants （Kb） was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex＇s LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru（MeIm）42ntz]^2＋ （3） can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model （CPCM）, and were in good agreement with the experimental results.展开更多
This paper investigates the stability analysis and H_∞ control for a class of nonlinear timedelay systems,and proposes a number of new results.Firstly,an equivalent form is given for this class of systems by means of...This paper investigates the stability analysis and H_∞ control for a class of nonlinear timedelay systems,and proposes a number of new results.Firstly,an equivalent form is given for this class of systems by means of coordinate transformation and orthogonal decomposition of vector fields.Then,based on the equivalent form,some delay-dependent results are derived for the stability analysis of the systems by constructing a novel Lyapunov functional.Thirdly,the authors use the equivalent form and the obtained stability results to investigate the H_∞ control problem for a class of nonhnear time-delay control systems,and present a control design procedure.Finally,an illustrative example is given to show the effectiveness of the results obtained in this paper.It is shown that the main results of this paper are easier to check than some existing ones,and have less conservatism.展开更多
基金This work was supported by National Nature Science Foundation of China and China Academy of Engineering Physics （No. 10376021） Provincial National Science Foundation of He＇nan （No. 2004601107）.
文摘Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analysis （HCA） were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20903027）, the Natural Science Foundation of Guangdong Province of China （No.9452402301001941）, the Medical Scientific Research Foundation of Guangdong Province of China （No.B2013297）, and the University Student in Guangdong Province Innovation and Entrepreneurship Train ing Program （No.1057112019 and No.1057112013）.
文摘Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole complexes, i.e. [Ru（Mehn）4iip]^2＋ （1） （MeIm=l-methylimidazole, iip=2-（1H-imidazo-4-group）-lH-imidazo[n,5-f][1,10]phenanthroline）, [Ru（MeIm）4tip]^2＋ （2） （tip=2-（thiophene-2-group）-lH-imidazo[4,5-f] [i,10]phenanthroline）, and [Ru（Melm）42ntz]^2＋ （3） （2ntz=2-（2-nitro-l,3-thiazole-5-group）-lH-imidazo[4,5-f][1,10]phenanthroline）, were car- ried out using the density functional theory （DFT）. The electronic structures of these Ru（II） complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants （Kb） was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex＇s LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru（MeIm）42ntz]^2＋ （3） can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model （CPCM）, and were in good agreement with the experimental results.
基金supported by the National Natural Science Foundation of China under Grant Nos.G60774009,61074068,61034007,61374065,and 61304033the Research Fund for the Doctoral Program of Chinese Higher Education under Grant No.200804220028+1 种基金the Natural Science Foundation of Shandong Province under Grant Nos.ZR2013ZEM006,ZR2011EL021,BS2011ZZ012,2013ZRB01873Colleges and Universities in Shandong Province Science and Technology Project under Grant Nos.J13LN37 and J12LN29
文摘This paper investigates the stability analysis and H_∞ control for a class of nonlinear timedelay systems,and proposes a number of new results.Firstly,an equivalent form is given for this class of systems by means of coordinate transformation and orthogonal decomposition of vector fields.Then,based on the equivalent form,some delay-dependent results are derived for the stability analysis of the systems by constructing a novel Lyapunov functional.Thirdly,the authors use the equivalent form and the obtained stability results to investigate the H_∞ control problem for a class of nonhnear time-delay control systems,and present a control design procedure.Finally,an illustrative example is given to show the effectiveness of the results obtained in this paper.It is shown that the main results of this paper are easier to check than some existing ones,and have less conservatism.
