Di-(2'-deoxy-2'-fluoro)-cytidine and -urinal phosphate and phosphorothioate were synthesized by phosphoramidite approach.The diastereomer separation of the protected phosphorothioates was performed by preparat...Di-(2'-deoxy-2'-fluoro)-cytidine and -urinal phosphate and phosphorothioate were synthesized by phosphoramidite approach.The diastereomer separation of the protected phosphorothioates was performed by preparative thin layer cbromatograpby.Investigation on ribozyme and anti-sense oligonucleotides stimulates the synthesis of chemically展开更多
Diisobutylaluminium hydride （DIBAL-H） promotes secondary rim regioselective bis-de-O-methylation of permethylated β- cyclodextrin （β-CD） to give diol 2. To gain an insight into the mechanism of this remarkable r...Diisobutylaluminium hydride （DIBAL-H） promotes secondary rim regioselective bis-de-O-methylation of permethylated β- cyclodextrin （β-CD） to give diol 2. To gain an insight into the mechanism of this remarkable regioselective behavior, two corresponding permethylated β-CDs with an alcohol function at either 2- or 3-position were synthesized in our previous study. As a step further to this work, the two compounds were subjected to deoxygenation reaction with tributyltin hydride in the present of 2,2＇- azobisisobutyronitrile affording the corresponding 2- and 3-deoxy permethylated β-CD derivatives （19 and 16）. The structures of these two compounds were characterized by 1D and 2D NMR and HRMS. Compounds 16 and 19 were unable to react with DIBAL- H which suggests that O-2A and O-3B are necessary for DIBAL-H promoted bis-de-O-methylation reaction of permethylated β-CD.展开更多
We really appreciated Lin et al.’s“The influence of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography on the N-and M-staging and subsequent clinical management of intrahepatic cholangiocarci...We really appreciated Lin et al.’s“The influence of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography on the N-and M-staging and subsequent clinical management of intrahepatic cholangiocarcinoma”in HepatoBiliary Surgery and Nutrition(1).A 291-patient population affected by intrahepatic cholangiocarcinoma(ICC)was retrospectively analyzed with the aim of assessing the accuracy of preoperative staging and treatment reallocation by ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT)(1).展开更多
Data security is a major cloud computing issue due to different usertransactions in the system. The evolution of cryptography and cryptographic analysis are regarded domains of current research. deoxyribo nucleic aci...Data security is a major cloud computing issue due to different usertransactions in the system. The evolution of cryptography and cryptographic analysis are regarded domains of current research. deoxyribo nucleic acid (DNA) cryptography makes use of DNA as a sensing platform, which is then manipulated usinga variety of molecular methods. Many security mechanisms including knowledgebased authentication, two-factor authentication, adaptive authentication, multifactorauthentication and single password authentication have been deployed. These cryptographic techniques have been developed to ensure confidentiality, but most ofthem are based on complex mathematical calculations and equations. In the proposed approach, a novel and unique Hybrid helix scuttle-deoxy ribo nucleic acids(HHS-DNA) encryption algorithm has been proposed which is inspired by DNAcryptography and Helix scuttle. The proposed HHS-DNA is a type of multifold binary version of DNA (MF-BDNA). The major role of this paper is to present a multifold HHS-DNA algorithm to encrypt the cloud data assuring more security with lesscomplexity. The experimentation is carried out and it reduces the encryption time,cipher text size, and improves throughput. When compared with previous techniques, there is a 45% improvement in throughput, 37% fast in encryption time,54.67% cipher text size. The relevant experimental results and foregoing analysisshow that this method is of good robustness, stability, and security.展开更多
Polysaceharide is a polyhydroxyl maeromolecular compound. Owing to the influence of the intermolecular and intramolecular hydrogenbonds and difficulty in achieving reaction in solution, it is difficult to obtain produ...Polysaceharide is a polyhydroxyl maeromolecular compound. Owing to the influence of the intermolecular and intramolecular hydrogenbonds and difficulty in achieving reaction in solution, it is difficult to obtain products of its complete or selective substitution in the research of polysaccharide modification or structure. The展开更多
The introduction of a 15-methyl group into a prostaglandin E2 （or its methyl ester） molecule blocks the metabolic action of the 15-hydroxyprostaglandin dehydrogenase and results in a considerable increase of the bio...The introduction of a 15-methyl group into a prostaglandin E2 （or its methyl ester） molecule blocks the metabolic action of the 15-hydroxyprostaglandin dehydrogenase and results in a considerable increase of the biological activities as well as prolongs the duration of the action of resulting derivative. Up to date, only one route for展开更多
文摘Di-(2'-deoxy-2'-fluoro)-cytidine and -urinal phosphate and phosphorothioate were synthesized by phosphoramidite approach.The diastereomer separation of the protected phosphorothioates was performed by preparative thin layer cbromatograpby.Investigation on ribozyme and anti-sense oligonucleotides stimulates the synthesis of chemically
基金Financial support of this study from CNRS is gratefully acknowledged
文摘Diisobutylaluminium hydride （DIBAL-H） promotes secondary rim regioselective bis-de-O-methylation of permethylated β- cyclodextrin （β-CD） to give diol 2. To gain an insight into the mechanism of this remarkable regioselective behavior, two corresponding permethylated β-CDs with an alcohol function at either 2- or 3-position were synthesized in our previous study. As a step further to this work, the two compounds were subjected to deoxygenation reaction with tributyltin hydride in the present of 2,2＇- azobisisobutyronitrile affording the corresponding 2- and 3-deoxy permethylated β-CD derivatives （19 and 16）. The structures of these two compounds were characterized by 1D and 2D NMR and HRMS. Compounds 16 and 19 were unable to react with DIBAL- H which suggests that O-2A and O-3B are necessary for DIBAL-H promoted bis-de-O-methylation reaction of permethylated β-CD.
基金supported by Italian Ministry of Health-Ricerca Corrente Annual Program 2023.
文摘We really appreciated Lin et al.’s“The influence of ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography on the N-and M-staging and subsequent clinical management of intrahepatic cholangiocarcinoma”in HepatoBiliary Surgery and Nutrition(1).A 291-patient population affected by intrahepatic cholangiocarcinoma(ICC)was retrospectively analyzed with the aim of assessing the accuracy of preoperative staging and treatment reallocation by ^(18)F-fluorodeoxyglucose positron emission tomography/computed tomography(^(18)F-FDG PET/CT)(1).
文摘Data security is a major cloud computing issue due to different usertransactions in the system. The evolution of cryptography and cryptographic analysis are regarded domains of current research. deoxyribo nucleic acid (DNA) cryptography makes use of DNA as a sensing platform, which is then manipulated usinga variety of molecular methods. Many security mechanisms including knowledgebased authentication, two-factor authentication, adaptive authentication, multifactorauthentication and single password authentication have been deployed. These cryptographic techniques have been developed to ensure confidentiality, but most ofthem are based on complex mathematical calculations and equations. In the proposed approach, a novel and unique Hybrid helix scuttle-deoxy ribo nucleic acids(HHS-DNA) encryption algorithm has been proposed which is inspired by DNAcryptography and Helix scuttle. The proposed HHS-DNA is a type of multifold binary version of DNA (MF-BDNA). The major role of this paper is to present a multifold HHS-DNA algorithm to encrypt the cloud data assuring more security with lesscomplexity. The experimentation is carried out and it reduces the encryption time,cipher text size, and improves throughput. When compared with previous techniques, there is a 45% improvement in throughput, 37% fast in encryption time,54.67% cipher text size. The relevant experimental results and foregoing analysisshow that this method is of good robustness, stability, and security.
文摘Polysaceharide is a polyhydroxyl maeromolecular compound. Owing to the influence of the intermolecular and intramolecular hydrogenbonds and difficulty in achieving reaction in solution, it is difficult to obtain products of its complete or selective substitution in the research of polysaccharide modification or structure. The
文摘The introduction of a 15-methyl group into a prostaglandin E2 （or its methyl ester） molecule blocks the metabolic action of the 15-hydroxyprostaglandin dehydrogenase and results in a considerable increase of the biological activities as well as prolongs the duration of the action of resulting derivative. Up to date, only one route for
