Phosphodiester bonds are the backbone linkages of all the nucleic acids which store and transfer biological information.The hydrolysis of phosphodiester bonds is of great importance to the replication,recombination,an...Phosphodiester bonds are the backbone linkages of all the nucleic acids which store and transfer biological information.The hydrolysis of phosphodiester bonds is of great importance to the replication,recombination,and damage repair of DNA as well as the maturation and processing of RNA.However,the spontaneous scission of individual phosphodiester linkages is kinetically challenging under physiological conditions,with an estimated half-life of 30 million years.Here,we discover a defect-engineered Zr-metal-organic framework(Zr-MOF)nanozyme containing cluster-missing reo defects,named UiO-66 REO,that possesses intrinsic phosphodiesterase-like activity that allows for the cleavage of the phosphodiester bond in physiological condition(pH=7.4 and 37℃),outperforming the activityrecording Zr-MOFs.The atomic-level structure of the UiO-66 REO nanozyme has been directly identified by the synchrotron radiation absorption spectrum and integrated differential phase contrast-scanning transmission electron microscopy.We find that both the defective boundary regions and unusual Zr6-clusters formed in the reo phase of the UiO-66 REO nanozyme contribute to the improvement in efficiency of phosphodiesterase-like hydrolysis,which realizes the cleavage of DNA in mild conditions.This work offers a new insight into biomimetic enzymology using crystal and defect engineering and opens up new possibilities for the development of low-cost,structurally stable and sustainable phosphodiesterase nanozymes for different biological applications.展开更多
This paper proposed a multi-period dynamic optimal portfolio selection model. Assumptions were made to assure the strictness of reasoning. This Approach depicted the developments and changing of the real stock market ...This paper proposed a multi-period dynamic optimal portfolio selection model. Assumptions were made to assure the strictness of reasoning. This Approach depicted the developments and changing of the real stock market and is an attempt to remedy some of the deficiencies of recent researches. The model is a standard form of quadratic programming. Furthermore, this paper presented a numerical example in real stock market.展开更多
In continuation of our efforts toward the discovery of potent HIV-1 NNRTIs with diverse structures,a series of novel S-DACO analogues of 6-(2-cyclohexyl-1-allkyl)-2-(2-oxo-2-phenyl-ethylsulfanyl)pyrimidin-4(3 H)-ones ...In continuation of our efforts toward the discovery of potent HIV-1 NNRTIs with diverse structures,a series of novel S-DACO analogues of 6-(2-cyclohexyl-1-allkyl)-2-(2-oxo-2-phenyl-ethylsulfanyl)pyrimidin-4(3 H)-ones were designed,synthesized and evaluated for their antiviral activities in MT-4 cells.Most of these new compounds showed moderate to good activities against wild type HIV-1 with IC_(50) values ranging from 7.55μmol/L to 0.018μmol/L.Among them,compound 5 c was identified as the most promising inhibitor against HIV-1 replication with an IC_(50)=0.018μmol/L,CC_(50)=194μmol/L,and SI=12791,which was much more potent than the reference drugs NVP and DLV and comparable to AZT and EFV.In addition,5 c also exhibited improved activity against double mutant HIV-1 strain RES056 compared to that of the reference drugs NVP/DLV and DB02.The preliminary structure-activity relationship(SAR)and molecular modeling studies were also discussed,which provides some useful indications for guiding the further rational design of new S-DACO analogues.展开更多
Linear and mixed integer programming are very popular and important methods to make efficient scientific management decision.With large size of real application data,the use of linear-mixed integer programming is faci...Linear and mixed integer programming are very popular and important methods to make efficient scientific management decision.With large size of real application data,the use of linear-mixed integer programming is facing problems with more complexity;therefore,preprocessing techniques become very important.Preprocessing aims to check and delete redundant information from the problem formulation.It is a collection of techniques that reduce the size of the problem and try to strengthen the formulation.Fast and effective preprocessing techniques are very important and essential for solving linear or mixed integer programming instances.In this paper,we demonstrate a set of techniques to presolve linear and mixed integer programming problems.Experiment results showed that when preprocessing is well done,then it becomes easier for the solver;we implemented interior-point algorithm for computational experiment.However,preprocessing is not enough to reduce the size and total nonzero elements from the constraints matrix.Moreover,we also demonstrate the impact of minimum degree reordering on the speed and storage requirements of a matrix operation.All techniques mentioned above are presented in a multifunctional software to facilitate users.展开更多
基金financially supported by the projects of the National Natural Science Foundation of China (grant nos.22174164,G.C.,22104159,S.H.)the Natural Science Foundation of Guangzhou City (grant no.202201011408,G.C.)the Fundamental Research Funds for the Central Universities,and Sun Yat-sen University (grant no.23lgbj005,G.C.).
文摘Phosphodiester bonds are the backbone linkages of all the nucleic acids which store and transfer biological information.The hydrolysis of phosphodiester bonds is of great importance to the replication,recombination,and damage repair of DNA as well as the maturation and processing of RNA.However,the spontaneous scission of individual phosphodiester linkages is kinetically challenging under physiological conditions,with an estimated half-life of 30 million years.Here,we discover a defect-engineered Zr-metal-organic framework(Zr-MOF)nanozyme containing cluster-missing reo defects,named UiO-66 REO,that possesses intrinsic phosphodiesterase-like activity that allows for the cleavage of the phosphodiester bond in physiological condition(pH=7.4 and 37℃),outperforming the activityrecording Zr-MOFs.The atomic-level structure of the UiO-66 REO nanozyme has been directly identified by the synchrotron radiation absorption spectrum and integrated differential phase contrast-scanning transmission electron microscopy.We find that both the defective boundary regions and unusual Zr6-clusters formed in the reo phase of the UiO-66 REO nanozyme contribute to the improvement in efficiency of phosphodiesterase-like hydrolysis,which realizes the cleavage of DNA in mild conditions.This work offers a new insight into biomimetic enzymology using crystal and defect engineering and opens up new possibilities for the development of low-cost,structurally stable and sustainable phosphodiesterase nanozymes for different biological applications.
文摘This paper proposed a multi-period dynamic optimal portfolio selection model. Assumptions were made to assure the strictness of reasoning. This Approach depicted the developments and changing of the real stock market and is an attempt to remedy some of the deficiencies of recent researches. The model is a standard form of quadratic programming. Furthermore, this paper presented a numerical example in real stock market.
基金financial support from the National Natural Science Foundation of China(Nos.21967020,U1702286,21362017,21262044)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT17R94,China)Fund of Academician Working Station of Yunnan Province(No.2018IC057)。
文摘In continuation of our efforts toward the discovery of potent HIV-1 NNRTIs with diverse structures,a series of novel S-DACO analogues of 6-(2-cyclohexyl-1-allkyl)-2-(2-oxo-2-phenyl-ethylsulfanyl)pyrimidin-4(3 H)-ones were designed,synthesized and evaluated for their antiviral activities in MT-4 cells.Most of these new compounds showed moderate to good activities against wild type HIV-1 with IC_(50) values ranging from 7.55μmol/L to 0.018μmol/L.Among them,compound 5 c was identified as the most promising inhibitor against HIV-1 replication with an IC_(50)=0.018μmol/L,CC_(50)=194μmol/L,and SI=12791,which was much more potent than the reference drugs NVP and DLV and comparable to AZT and EFV.In addition,5 c also exhibited improved activity against double mutant HIV-1 strain RES056 compared to that of the reference drugs NVP/DLV and DB02.The preliminary structure-activity relationship(SAR)and molecular modeling studies were also discussed,which provides some useful indications for guiding the further rational design of new S-DACO analogues.
基金sponsored by CAS-TWAS President’s Fellowship for International PhD Students
文摘Linear and mixed integer programming are very popular and important methods to make efficient scientific management decision.With large size of real application data,the use of linear-mixed integer programming is facing problems with more complexity;therefore,preprocessing techniques become very important.Preprocessing aims to check and delete redundant information from the problem formulation.It is a collection of techniques that reduce the size of the problem and try to strengthen the formulation.Fast and effective preprocessing techniques are very important and essential for solving linear or mixed integer programming instances.In this paper,we demonstrate a set of techniques to presolve linear and mixed integer programming problems.Experiment results showed that when preprocessing is well done,then it becomes easier for the solver;we implemented interior-point algorithm for computational experiment.However,preprocessing is not enough to reduce the size and total nonzero elements from the constraints matrix.Moreover,we also demonstrate the impact of minimum degree reordering on the speed and storage requirements of a matrix operation.All techniques mentioned above are presented in a multifunctional software to facilitate users.
