The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have...The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have complicated structure, direct determination of this parameter takes time, spends expenditure and requires accuracy. On the other hand, there are no precise equations for indirect determination of it; most of them are empirical. By using data sets of several dams of Iran and neuro-genetic, adaptive neuro-fuzzy inference system （ANFIS）, and gene expression programming （GEP） methods, models are rendered for prediction of shear wave velocity in limestone. Totally, 516 sets of data has been used for modeling. From these data sets, 413 ones have been utilized for building the intelligent model, and 103 have been used for their performance evaluation. Compressional wave velocity （Vp）, density （7） and porosity （.n）, were considered as input parameters. Respectively, the amount of R for neuro-genetic and ANFIS networks was 0.959 and 0.963. In addition, by using GEP, three equations are obtained; the best of them has 0.958R. ANFIS shows the best prediction results, whereas GEP indicates proper equations. Because these equations have accuracy, they could be used for prediction of shear wave velocity for limestone in the future.展开更多
Genetic structure data of five populations of the Luehea divaricata Mart. ＆ Zucc., forest tree species under development in the Atlantic Forest biome, obtained by microsatellite DNA markers, were used in simulations ...Genetic structure data of five populations of the Luehea divaricata Mart. ＆ Zucc., forest tree species under development in the Atlantic Forest biome, obtained by microsatellite DNA markers, were used in simulations to study their reproductive and ecological pattern. Different selfing and migration rates were tested, using the observed and expected heterozygosity of 0.55 and 0.67, respectively, obtained through the use of microsatellite markers. Closest values were obtained with the use of selfing rates of 0.3 and migration of 0.2. These results suggest the presence of some self-incompatibility system between these species, which reduces, but does not prevent the self-fertilization. The migration rate contributes to a low genetic differentiation between the populations, making the reproductive mode, responsible for the inbreeding observed in the same populations. Authors suggest continuous monitoring of the genetic variability as a guarantee for the persistence of these populations. The study focus on the importance of using computer simulations to investigate ecologic, reproductive and genetic patterns for forestry populations, thus enabling the application of suitable measures for conservation.展开更多
Infectious bursal disease virus （IBDV） poses a significant threat to the poultry industry. Viral protein 2 （VP2）, the major struc- tural protein of IBDV, has been subjected to frequent mutations that have imparted...Infectious bursal disease virus （IBDV） poses a significant threat to the poultry industry. Viral protein 2 （VP2）, the major struc- tural protein of IBDV, has been subjected to frequent mutations that have imparted tremendous genetic diversity to the virus. To determine how amino acid mutations may affect the virulence of IBDV, we built a structural model of VP2 of a very virulent strain of IBDV identified in China, vvIBDV Gx, and performed a molecular dynamics simulation of the interaction between virulence sites. The study showed that the amino acid substitutions that distinguish vvlBDV from attenuated IBDV （H253Q and T284A） favor a hydrophobic and flexible conformation of β-barrel loops in VP2, which could promote interac- tions between the virus and potential IBDV-specific receptors. Population sequence analysis revealed that the IBDV strains prevalent in East Asia show a significant signal of positive selection at virulence sites 253 and 284. In addition, a signal of co-evolution between sites 253 and 284 was identified. These results suggest that changes in the virulence of IBDV may result from both the interaction and the co-evolution of multiple amino acid substitutions at virulence sites.展开更多
Pacemaking dysfunction has become a significant disease that may contribute to heart rhythm disorders,syncope,and even death.Up to now,the best way to treat it is to implant electronic pacemakers.However,these have ma...Pacemaking dysfunction has become a significant disease that may contribute to heart rhythm disorders,syncope,and even death.Up to now,the best way to treat it is to implant electronic pacemakers.However,these have many disadvantages such as limited battery life,infection,and fixed pacing rate.There is an urgent need for a biological pacemaker(bio-pacemaker).This is expected to replace electronic devices because of its low risk of complications and the ability to respond to emotion.Here we survey the contemporary development of the bio-pacemaker by both experimental and computational approaches.The former mainly includes gene therapy and cell therapy,whilst the latter involves the use of multi-scale computer models of the heart,ranging from the single cell to the tissue slice.Up to now,a bio-pacemaker has been successfully applied in big mammals,but it still has a long way from clinical uses for the treatment of human heart diseases.It is hoped that the use of the computational model of a bio-pacemaker may accelerate this process.Finally,we propose potential research directions for generating a bio-pacemaker based on cardiac computational modeling.展开更多
Saframycin A(SFM-A),a tetrahydroisoquinoline antibiotic isolated from Streptomyces lavendulae,shows potent anti-proliferation activities against a variety of tumor cell lines,and shares the core structure with ecteina...Saframycin A(SFM-A),a tetrahydroisoquinoline antibiotic isolated from Streptomyces lavendulae,shows potent anti-proliferation activities against a variety of tumor cell lines,and shares the core structure with ecteinascidin 743(ET-743),the anticancer drug for soft-tissue sarcoma.Characterization of the SFM-A biosynthetic gene cluster revealed three nonribosomal peptide synthetase genes and a series of genes encoding oxygenases.To investigate the function of sfmO2 gene,encoding a FAD-dependent monooxygenase/hydroxylase,we constructed the gene replacement mutant(△sfmO2) strain S.lavendulae TL2007 and the corresponding gene complementation mutant strain S.lavendulae TL2008.A novel compound,SFM-O,was isolated from the △sfmO2 replacement mutant strain and its structure was characterized by comparison to the HRMS and NMR spectra of SFM-A.These findings indicated that SfmO2 is responsible for the oxidation of ring A in the biosynthetic pathway of SFM-A,and the new compound SFM-O could be considered as an advanced intermediate in the semisynthesis of ET-743.展开更多
The abnormality monitoring model (AMM) of cracks in concrete dams is established through integrating safety monitoring theories with abnormality diagnosis methods of cracks. In addition, emphasis is placed on the infl...The abnormality monitoring model (AMM) of cracks in concrete dams is established through integrating safety monitoring theories with abnormality diagnosis methods of cracks. In addition, emphasis is placed on the influence of crack depth on crack mouth opening displacement (CMOD). A linear hypothesis is proposed for the propagation process of cracks in concrete based on the fictitious crack model (FCM). Abnormality points are detected through testing methods of dynamical structure mutation and statistical model mutation. The solution of AMM is transformed into a global optimization problem, which is solved by the particle swarm optimization (PSO) method. Therefore, the AMM of cracks in concrete dams is established and solved completely. In the end of the paper, the proposed model is validated by a typical crack at the 105 m elevation of a concrete gravity arch dam.展开更多
文摘The main purpose of current study is development of an intelligent model for estimation of shear wave velocity in limestone. Shear wave velocity is one of the most important rock dynamic parameters. Because rocks have complicated structure, direct determination of this parameter takes time, spends expenditure and requires accuracy. On the other hand, there are no precise equations for indirect determination of it; most of them are empirical. By using data sets of several dams of Iran and neuro-genetic, adaptive neuro-fuzzy inference system （ANFIS）, and gene expression programming （GEP） methods, models are rendered for prediction of shear wave velocity in limestone. Totally, 516 sets of data has been used for modeling. From these data sets, 413 ones have been utilized for building the intelligent model, and 103 have been used for their performance evaluation. Compressional wave velocity （Vp）, density （7） and porosity （.n）, were considered as input parameters. Respectively, the amount of R for neuro-genetic and ANFIS networks was 0.959 and 0.963. In addition, by using GEP, three equations are obtained; the best of them has 0.958R. ANFIS shows the best prediction results, whereas GEP indicates proper equations. Because these equations have accuracy, they could be used for prediction of shear wave velocity for limestone in the future.
文摘Genetic structure data of five populations of the Luehea divaricata Mart. ＆ Zucc., forest tree species under development in the Atlantic Forest biome, obtained by microsatellite DNA markers, were used in simulations to study their reproductive and ecological pattern. Different selfing and migration rates were tested, using the observed and expected heterozygosity of 0.55 and 0.67, respectively, obtained through the use of microsatellite markers. Closest values were obtained with the use of selfing rates of 0.3 and migration of 0.2. These results suggest the presence of some self-incompatibility system between these species, which reduces, but does not prevent the self-fertilization. The migration rate contributes to a low genetic differentiation between the populations, making the reproductive mode, responsible for the inbreeding observed in the same populations. Authors suggest continuous monitoring of the genetic variability as a guarantee for the persistence of these populations. The study focus on the importance of using computer simulations to investigate ecologic, reproductive and genetic patterns for forestry populations, thus enabling the application of suitable measures for conservation.
基金supported by the National Natural Science Foundation of China(31230018,31430087)the National Science and Technology Major Project for infectious disease of China(2013ZX10004606)
文摘Infectious bursal disease virus （IBDV） poses a significant threat to the poultry industry. Viral protein 2 （VP2）, the major struc- tural protein of IBDV, has been subjected to frequent mutations that have imparted tremendous genetic diversity to the virus. To determine how amino acid mutations may affect the virulence of IBDV, we built a structural model of VP2 of a very virulent strain of IBDV identified in China, vvIBDV Gx, and performed a molecular dynamics simulation of the interaction between virulence sites. The study showed that the amino acid substitutions that distinguish vvlBDV from attenuated IBDV （H253Q and T284A） favor a hydrophobic and flexible conformation of β-barrel loops in VP2, which could promote interac- tions between the virus and potential IBDV-specific receptors. Population sequence analysis revealed that the IBDV strains prevalent in East Asia show a significant signal of positive selection at virulence sites 253 and 284. In addition, a signal of co-evolution between sites 253 and 284 was identified. These results suggest that changes in the virulence of IBDV may result from both the interaction and the co-evolution of multiple amino acid substitutions at virulence sites.
基金Project supported by the National Natural Science Foundation of China(Nos.61572152,61601143,and 81770328)the Science Technology and Innovation Commission of Shenzhen Municipality(Nos.JCYJ20151029173639477 and JSGG20160229125049615)the China Postdoctoral Science Foundation(No.2015M581448)。
文摘Pacemaking dysfunction has become a significant disease that may contribute to heart rhythm disorders,syncope,and even death.Up to now,the best way to treat it is to implant electronic pacemakers.However,these have many disadvantages such as limited battery life,infection,and fixed pacing rate.There is an urgent need for a biological pacemaker(bio-pacemaker).This is expected to replace electronic devices because of its low risk of complications and the ability to respond to emotion.Here we survey the contemporary development of the bio-pacemaker by both experimental and computational approaches.The former mainly includes gene therapy and cell therapy,whilst the latter involves the use of multi-scale computer models of the heart,ranging from the single cell to the tissue slice.Up to now,a bio-pacemaker has been successfully applied in big mammals,but it still has a long way from clinical uses for the treatment of human heart diseases.It is hoped that the use of the computational model of a bio-pacemaker may accelerate this process.Finally,we propose potential research directions for generating a bio-pacemaker based on cardiac computational modeling.
基金supported in part by grants from the National Natural Science Foundation of China(20832009,and 20921091)the Chinese Academy of Sciences and Open Funding Project of the State Key Laboratory of Bioreactor Engineering
文摘Saframycin A(SFM-A),a tetrahydroisoquinoline antibiotic isolated from Streptomyces lavendulae,shows potent anti-proliferation activities against a variety of tumor cell lines,and shares the core structure with ecteinascidin 743(ET-743),the anticancer drug for soft-tissue sarcoma.Characterization of the SFM-A biosynthetic gene cluster revealed three nonribosomal peptide synthetase genes and a series of genes encoding oxygenases.To investigate the function of sfmO2 gene,encoding a FAD-dependent monooxygenase/hydroxylase,we constructed the gene replacement mutant(△sfmO2) strain S.lavendulae TL2007 and the corresponding gene complementation mutant strain S.lavendulae TL2008.A novel compound,SFM-O,was isolated from the △sfmO2 replacement mutant strain and its structure was characterized by comparison to the HRMS and NMR spectra of SFM-A.These findings indicated that SfmO2 is responsible for the oxidation of ring A in the biosynthetic pathway of SFM-A,and the new compound SFM-O could be considered as an advanced intermediate in the semisynthesis of ET-743.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51079046, 50909041, 50809025, 50879024)the National Science and Technology Support Plan (Grant Nos. 2008BAB29B03, 2008BAB29B06)+5 种基金the Special Fund of State Key Laboratory of China (Grant Nos. 2009586012, 2009586912, 2010585212)the Fundamental Research Funds for the Central Universities (Grant Nos. 2009B08514, 2010B20414, 2010B01414, 2010B14114)China Hydropower Engineering Consulting Group Co. Science and Technology Support Project (Grant No. CHC-KJ-2007-02)Jiangsu Province "333 High-Level Personnel Training Project" (Grant No. 2017-B08037)Graduate Innovation Program of Universities in Jiangsu Province (Grant No. CX09B_163Z)Science Foundation for The Excellent Youth Scholars of Ministry of Education of China (Grant No. 20070294023)
文摘The abnormality monitoring model (AMM) of cracks in concrete dams is established through integrating safety monitoring theories with abnormality diagnosis methods of cracks. In addition, emphasis is placed on the influence of crack depth on crack mouth opening displacement (CMOD). A linear hypothesis is proposed for the propagation process of cracks in concrete based on the fictitious crack model (FCM). Abnormality points are detected through testing methods of dynamical structure mutation and statistical model mutation. The solution of AMM is transformed into a global optimization problem, which is solved by the particle swarm optimization (PSO) method. Therefore, the AMM of cracks in concrete dams is established and solved completely. In the end of the paper, the proposed model is validated by a typical crack at the 105 m elevation of a concrete gravity arch dam.
