Fast and precise prediction of the receptor-ligand binding constant is an important aspect of structure-based drug design. Almost all de novo design methods or 3D database search methods tend to structure generation i...Fast and precise prediction of the receptor-ligand binding constant is an important aspect of structure-based drug design. Almost all de novo design methods or 3D database search methods tend to structure generation instead of structure evaluation. In this article, epididymal retinoic acid binding protein (ERABP) was used as a template to simulate the interaction between retinoids and their receptor. We deduced an equation predicting the drug-receptor binding constant. Furthermore, the conformers after docking were used in CoMFA analysis to get a pharmacophore model of this series of compounds.展开更多
By using active principles of Chinese medicinal materials as lead compounds soquinoline derivatives have been designed and synthesized.Their chemical structures include bisbenzylisoquinoline,benzyl-isoquinoline and pr...By using active principles of Chinese medicinal materials as lead compounds soquinoline derivatives have been designed and synthesized.Their chemical structures include bisbenzylisoquinoline,benzyl-isoquinoline and protoberberine.Their cardiovascular effects were studied involving α-adrenoceptor,adenosine A_1,A_2 and DPH-calcium channel radioreceptor assays.In addition,calmodulin inhibiting,calcium antagonistic potassium channel blocking and antiplatelet aggre- gation activities were also performed.It was found that compound VI_(19) was a new potassium channe blocker with α-adrenoceptor antagonism,compound V_9,and V_(21) lowered blood pressure on various animal models with negative chronotropic action,compound VI_(13)possessed antiarrhythmic and antifi- brillation action,and it may be a candidate tot clinic evaluation.The structure-activity relationships deduced may provide a theoretical basis for further development of new agents.展开更多
Aim and Method Comparative molecular field analysis (CoMFA), a threedimensional quantitative structure-activity relationship (3D-QSAR) method was applied to a novelseries of C-3 substituted 4, 6-dichloioindole-2-carbo...Aim and Method Comparative molecular field analysis (CoMFA), a threedimensional quantitative structure-activity relationship (3D-QSAR) method was applied to a novelseries of C-3 substituted 4, 6-dichloioindole-2-carboxylic acids to study the relationship betweentheir structure and the affinity for the glycine site of the NMDA receptor. Result Hie coefficientsof cross-validation q^2 and non cross-validation r^2 for the model established by the study are0.744 and 0.993, respectively, the value of variance ratio F is 261.343, and standard error estimate(SE) is 0.039. Conclusion These values indicate that the CoMFA model may have a good prediction forthe activity of C-3 substituted 4, 6-dichloroin-dole-2-carboxylic acids. As a consequence, thepredicted activity values of new designed compounds supports our conclusion from the model.展开更多
A recently developed computerized method for assessing the rock joint coefficients is discussed. The performances of formerly introduced relative similarity indicators, along with the correlation coefficient, are subj...A recently developed computerized method for assessing the rock joint coefficients is discussed. The performances of formerly introduced relative similarity indicators, along with the correlation coefficient, are subjected to critical analysis. These relative numerical indicators are replaced by two absolute indicators whose properties better describe surface textures of rock joints. The first absolute indicator results from the Fourier Matrix and evaluates wavy shapes of surfaces. The second absolute indicator quantifies the heights of surface reliefs, and is defined as the root mean square height of the surface outline. The behavior of the newly introduced numerical indicators are investigated by means of the deterministic periodic surface reliefs. The practical application of the new indicators is presented and the convenient performances of both the indicators are documented.展开更多
Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology develop...Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick's model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.展开更多
2,5,6-Tribromo-l-methylgramine (TBG), isolated from bryozoan Zoobotryon pellucidum was shown to be very efficient in preventing recruitment of larval settlement. In order to improve the compatibility of TBG and its ...2,5,6-Tribromo-l-methylgramine (TBG), isolated from bryozoan Zoobotryon pellucidum was shown to be very efficient in preventing recruitment of larval settlement. In order to improve the compatibility of TBG and its analogues with other ingredients in antifouling paints, structural modification of TBG was focused mainly on halogen substitution and N-substitution. Two halogen-substitute gramines and their derivatives which contain ester functional groups at N-position of gramines were synthesized. Algal inhibition activities of the synthesized compounds against algae Nitzschia cIosterium were evaluated and the Median Effective Concentration (EC50) range was 1.06-6.74 lag ml^-1. Compounds that had a long chain ester group exhibited extremely high antifouling activity. Quantitive Structure Activity Relationship (QSAR) studies with multiple linear regression analysis were applied to fred correlation between different calculated molecular descriptors and biological activity of the synthesized compounds. The results show that the toxicity (log (I/EC50)) is correlated well with the partition coefficient log P. Thus, these products have potential function as antifouling agents.展开更多
The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay. Principal component analysis was carried out to ordinate the fatty acid patterns of seston in...The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay. Principal component analysis was carried out to ordinate the fatty acid patterns of seston in stations and months. The results showed that diatoms were most abundant in the phytoplankton at station A5 (located in the northwest of the bay: 36~9'N, 120~20'E) and least abundant at station D7 (located outside of the bay: 35~59'N, 120~26'E). By contrast, dinoflagellates were most abundant at station D7 and least abundant at station A5. According to the annual variations of 16:1 (o7 and 18:4(o3/ 16:1(o7, diatoms flourished mainly in spring and summer, while dinoflagellates bloomed exclusively in summer. A distinctive feature of the fatty acid composition of C. sinicus was the prevalence of 20:5o3 and 22:6(o3. The higher content of 16:1(o7 over 18:4(o3 in females indicated that diatoms contributed more than dinoflagellates to the diet of C. sinicus. The feeding intensity of C. sinicus on diatoms was higher in spring and autumn than in other seasons. The herbivorous indicators 20:1 and 22:1 were comparatively low, suggesting that besides phytoplankton, C. sinicus might feed on a wider range of particles including organic detritus, bacteria and small copepods.展开更多
The pinna of Cycasferruginea F.N. Wei (Cycadaceae), pinnas or rachises ofStangeria eriopus (Kune) Baill. (Stangeriaceae), Dioon holmgrenii De Luca, Sabato & Vazq. Torres, Macrozamia moorei F. Muell. ex C. Moore...The pinna of Cycasferruginea F.N. Wei (Cycadaceae), pinnas or rachises ofStangeria eriopus (Kune) Baill. (Stangeriaceae), Dioon holmgrenii De Luca, Sabato & Vazq. Torres, Macrozamia moorei F. Muell. ex C. Moore (Zamiaceae) were macerated and dissociated by Jeffrey's technique, rinsed with water, dehydrated and gold-plated for observation with scanning electron microscopes. The results showed that the pinna and rachis of the leaf tissues of the four cycad species possess many vessel elements and a few tracheid elements in the conducting tissue of the xylem. Annular, spiral, scalariform, pitted and reticulate vessels and some transitional types, including scalariform-pitted, scalariform-reticulate and reticulate-pitted vessels, were observed in the conducting tissues. The characteristics of the vessels of each species, and the evolutionary relation of four genera of cycads were analyzed. Compared with those of angiosperms, the structural characters of vessels of cycad are at the moderate level of evolution and more advanced than some primitive taxa of angiosperms and ferns. Vessels have been discovered in many genera of ferns, which are even more primitive than cycads. In many ferns, only vessel elements, but no tracheids are found in vascular tissue. In the present study, the authors discovered vessels in different genera of three families ofcycads which showed that the existence of vessels in primitive plant taxa is a widespread phenomenon. Vessel elements in vascular tissues of cycads have probably allowed cycads to adapt to various environmental stresses and enabled their persistence over their long evolutionary history. Cycads are the most primitive of the extant seed plants and the widespread existence of vessels in the group has broad implications for plant systematics, evolution and comparative morphology.展开更多
文摘Fast and precise prediction of the receptor-ligand binding constant is an important aspect of structure-based drug design. Almost all de novo design methods or 3D database search methods tend to structure generation instead of structure evaluation. In this article, epididymal retinoic acid binding protein (ERABP) was used as a template to simulate the interaction between retinoids and their receptor. We deduced an equation predicting the drug-receptor binding constant. Furthermore, the conformers after docking were used in CoMFA analysis to get a pharmacophore model of this series of compounds.
文摘By using active principles of Chinese medicinal materials as lead compounds soquinoline derivatives have been designed and synthesized.Their chemical structures include bisbenzylisoquinoline,benzyl-isoquinoline and protoberberine.Their cardiovascular effects were studied involving α-adrenoceptor,adenosine A_1,A_2 and DPH-calcium channel radioreceptor assays.In addition,calmodulin inhibiting,calcium antagonistic potassium channel blocking and antiplatelet aggre- gation activities were also performed.It was found that compound VI_(19) was a new potassium channe blocker with α-adrenoceptor antagonism,compound V_9,and V_(21) lowered blood pressure on various animal models with negative chronotropic action,compound VI_(13)possessed antiarrhythmic and antifi- brillation action,and it may be a candidate tot clinic evaluation.The structure-activity relationships deduced may provide a theoretical basis for further development of new agents.
文摘Aim and Method Comparative molecular field analysis (CoMFA), a threedimensional quantitative structure-activity relationship (3D-QSAR) method was applied to a novelseries of C-3 substituted 4, 6-dichloioindole-2-carboxylic acids to study the relationship betweentheir structure and the affinity for the glycine site of the NMDA receptor. Result Hie coefficientsof cross-validation q^2 and non cross-validation r^2 for the model established by the study are0.744 and 0.993, respectively, the value of variance ratio F is 261.343, and standard error estimate(SE) is 0.039. Conclusion These values indicate that the CoMFA model may have a good prediction forthe activity of C-3 substituted 4, 6-dichloroin-dole-2-carboxylic acids. As a consequence, thepredicted activity values of new designed compounds supports our conclusion from the model.
基金supported by the Grant Agency of the Czech Republic (No. 13-03403S)
文摘A recently developed computerized method for assessing the rock joint coefficients is discussed. The performances of formerly introduced relative similarity indicators, along with the correlation coefficient, are subjected to critical analysis. These relative numerical indicators are replaced by two absolute indicators whose properties better describe surface textures of rock joints. The first absolute indicator results from the Fourier Matrix and evaluates wavy shapes of surfaces. The second absolute indicator quantifies the heights of surface reliefs, and is defined as the root mean square height of the surface outline. The behavior of the newly introduced numerical indicators are investigated by means of the deterministic periodic surface reliefs. The practical application of the new indicators is presented and the convenient performances of both the indicators are documented.
基金This work was supported by the National Basic Research Program of China (No.2012CB215405), the National Natural Science Foundation of China (No.11374272), and the Specialized Research Fund for the Doctoral Program of Higher Education (No.20123402110064).
文摘Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick's model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.
基金Supported by the National Natural Science Foundation of China (No. 50673085, 20060423017, A1420080191)National High-Technology Research Program of China (863 Program, No. 2006AA09Z224)
文摘2,5,6-Tribromo-l-methylgramine (TBG), isolated from bryozoan Zoobotryon pellucidum was shown to be very efficient in preventing recruitment of larval settlement. In order to improve the compatibility of TBG and its analogues with other ingredients in antifouling paints, structural modification of TBG was focused mainly on halogen substitution and N-substitution. Two halogen-substitute gramines and their derivatives which contain ester functional groups at N-position of gramines were synthesized. Algal inhibition activities of the synthesized compounds against algae Nitzschia cIosterium were evaluated and the Median Effective Concentration (EC50) range was 1.06-6.74 lag ml^-1. Compounds that had a long chain ester group exhibited extremely high antifouling activity. Quantitive Structure Activity Relationship (QSAR) studies with multiple linear regression analysis were applied to fred correlation between different calculated molecular descriptors and biological activity of the synthesized compounds. The results show that the toxicity (log (I/EC50)) is correlated well with the partition coefficient log P. Thus, these products have potential function as antifouling agents.
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KZCX2-YW-213-3)the National Natural Science Foundation of China(Nos.40776092,40821004)
文摘The fatty acid compositions of seston and Calanus sinicus were investigated to study trophic relationships in Jiaozhou Bay. Principal component analysis was carried out to ordinate the fatty acid patterns of seston in stations and months. The results showed that diatoms were most abundant in the phytoplankton at station A5 (located in the northwest of the bay: 36~9'N, 120~20'E) and least abundant at station D7 (located outside of the bay: 35~59'N, 120~26'E). By contrast, dinoflagellates were most abundant at station D7 and least abundant at station A5. According to the annual variations of 16:1 (o7 and 18:4(o3/ 16:1(o7, diatoms flourished mainly in spring and summer, while dinoflagellates bloomed exclusively in summer. A distinctive feature of the fatty acid composition of C. sinicus was the prevalence of 20:5o3 and 22:6(o3. The higher content of 16:1(o7 over 18:4(o3 in females indicated that diatoms contributed more than dinoflagellates to the diet of C. sinicus. The feeding intensity of C. sinicus on diatoms was higher in spring and autumn than in other seasons. The herbivorous indicators 20:1 and 22:1 were comparatively low, suggesting that besides phytoplankton, C. sinicus might feed on a wider range of particles including organic detritus, bacteria and small copepods.
基金There are 8 projects supported by National Natural Science Foundation of China which Dr. Y.Y. Huang have taken charge of and/or taken part in Dr. Y.Y. Huang have published 5 bookmakings and more than 100 papers.
文摘The pinna of Cycasferruginea F.N. Wei (Cycadaceae), pinnas or rachises ofStangeria eriopus (Kune) Baill. (Stangeriaceae), Dioon holmgrenii De Luca, Sabato & Vazq. Torres, Macrozamia moorei F. Muell. ex C. Moore (Zamiaceae) were macerated and dissociated by Jeffrey's technique, rinsed with water, dehydrated and gold-plated for observation with scanning electron microscopes. The results showed that the pinna and rachis of the leaf tissues of the four cycad species possess many vessel elements and a few tracheid elements in the conducting tissue of the xylem. Annular, spiral, scalariform, pitted and reticulate vessels and some transitional types, including scalariform-pitted, scalariform-reticulate and reticulate-pitted vessels, were observed in the conducting tissues. The characteristics of the vessels of each species, and the evolutionary relation of four genera of cycads were analyzed. Compared with those of angiosperms, the structural characters of vessels of cycad are at the moderate level of evolution and more advanced than some primitive taxa of angiosperms and ferns. Vessels have been discovered in many genera of ferns, which are even more primitive than cycads. In many ferns, only vessel elements, but no tracheids are found in vascular tissue. In the present study, the authors discovered vessels in different genera of three families ofcycads which showed that the existence of vessels in primitive plant taxa is a widespread phenomenon. Vessel elements in vascular tissues of cycads have probably allowed cycads to adapt to various environmental stresses and enabled their persistence over their long evolutionary history. Cycads are the most primitive of the extant seed plants and the widespread existence of vessels in the group has broad implications for plant systematics, evolution and comparative morphology.