The review aims to present a classification and applicability analysis of methods for preliminary molecular modelling for targeted organic, catalytic and biocatalytic synthesis. The following three main approaches are considered as a primary classification of the methods: modelling of the target – ligand coordination without structural information on both the target and the resulting complex; calculations based on experimentally obtained structural information about the target; and dynamic simulation of the target – ligand complex and the reaction mechanism with calculation of the free energy of the reaction. The review is meant for synthetic chemists to be used as a guide for building an algorithm for preliminary modelling and synthesis of structures with specified properties. The bibliography includes 353 references.
{"title":"Preliminary modelling as the first stage of targeted organic synthesis","authors":"I. Titov, V. S. Stroylov, P. Rusina, I. Svitanko","doi":"10.1070/RCR5012","DOIUrl":"https://doi.org/10.1070/RCR5012","url":null,"abstract":"The review aims to present a classification and applicability analysis of methods for preliminary molecular modelling for targeted organic, catalytic and biocatalytic synthesis. The following three main approaches are considered as a primary classification of the methods: modelling of the target – ligand coordination without structural information on both the target and the resulting complex; calculations based on experimentally obtained structural information about the target; and dynamic simulation of the target – ligand complex and the reaction mechanism with calculation of the free energy of the reaction. The review is meant for synthetic chemists to be used as a guide for building an algorithm for preliminary modelling and synthesis of structures with specified properties. The bibliography includes 353 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48031561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The review addresses the prospects of global hydrogen energy development. Particular attention is given to the design of materials for sustainable hydrogen energy applications, including hydrogen production, purification, storage, and conversion to energy. The review highlights the key role of oxide-supported metal or alloy nanoparticles as catalysts in the hydrogen production via the conversion of natural gas or alcohols. An alternative approach is the pyrolysis of hydrocarbons giving hydrogen and carbon. The direct production of high-purity hydrogen can be performed using electrolysis or membrane catalysis. Apart from conventional hydrogen storage methods such as the compression and liquefaction, the hydrogen alloy absorption and chemical conversion to liquid carriers (ammonia and toluene cycles) are considered. Fuel cells, containing catalysts and proton-conducting membranes as the key components, are used for hydrogen energy generation. Binary platinum alloys or core – shell structures supported on carbon or oxides can be employed to facilitate the oxygen electroreduction and CO electrooxidation in low-temperature fuel cells. High conductivity and selectivity are provided by perfluorinated sulfonic acid membranes. The high cost of the latter materials dictates the development of alternative membrane materials. A crucial issue in high-temperature fuel cells is the necessity of reducing the operating temperature and ohmic losses. This problem can be solved by designing thin-film materials and replacing oxygen-conducting ceramic membranes by proton-conducting membranes. The bibliography includes 290 references.
{"title":"Hydrogen energy: development prospects and materials","authors":"S. Filippov, A. Yaroslavtsev","doi":"10.1070/RCR5014","DOIUrl":"https://doi.org/10.1070/RCR5014","url":null,"abstract":"The review addresses the prospects of global hydrogen energy development. Particular attention is given to the design of materials for sustainable hydrogen energy applications, including hydrogen production, purification, storage, and conversion to energy. The review highlights the key role of oxide-supported metal or alloy nanoparticles as catalysts in the hydrogen production via the conversion of natural gas or alcohols. An alternative approach is the pyrolysis of hydrocarbons giving hydrogen and carbon. The direct production of high-purity hydrogen can be performed using electrolysis or membrane catalysis. Apart from conventional hydrogen storage methods such as the compression and liquefaction, the hydrogen alloy absorption and chemical conversion to liquid carriers (ammonia and toluene cycles) are considered. Fuel cells, containing catalysts and proton-conducting membranes as the key components, are used for hydrogen energy generation. Binary platinum alloys or core – shell structures supported on carbon or oxides can be employed to facilitate the oxygen electroreduction and CO electrooxidation in low-temperature fuel cells. High conductivity and selectivity are provided by perfluorinated sulfonic acid membranes. The high cost of the latter materials dictates the development of alternative membrane materials. A crucial issue in high-temperature fuel cells is the necessity of reducing the operating temperature and ohmic losses. This problem can be solved by designing thin-film materials and replacing oxygen-conducting ceramic membranes by proton-conducting membranes. The bibliography includes 290 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59010299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Kashparova, Daria V. Chernysheva, V. Klushin, Veronika E. Andreeva, O. A. Kravchenko, N. Smirnova
Plant biomass is considered the main source of renewable carbon raw materials, which is a viable alternative to crude oil and natural gas and provides compounds with a low carbon footprint. The most promising direction for the conversion of biomass is the synthesis of 5-hydroxymethylfurfural, which is regarded as a platform chemical, the basis for the synthesis of valuable compounds, including monomers and polymers. The move of the polymer industry to renewable plant materials will contribute to solving global environmental problems and ensure the sustainability and environmental safety of plastics production. This review analyzes recent advances in the preparation of key C6-furan platform chemicals, such as 5-hydroxymethylfurfural, 2,5-furandicarboxylic acid, 2,5-diformylfuran, 2,5-bis(hydroxymethyl)furan, levulinic acid, and their use for the production of monomers and polymers based on renewable plant biomass. Production processes of widely known furan polyesters and polyamides, such as polyethylene-, polypropylene-, polybutylene furanoates, polyhexamethylene furanamide, are considered, as well as developments towards novel promising materials that are furan copolymers and polymer mixtures. For the first time, studies have been systematized aimed at converting liquid and solid wastes of the synthesis of platform chemicals, known as humins, into a range of value-added products, including organic compounds, porous carbon materials, thermosetting binders, and anticorrosive coatings that can replace similar materials based on fossil raw materials. Economic and environmental prospects and problems of production and consumption of furan polymers are considered. The bibliography includes 275 references.
{"title":"Furan monomers and polymers from renewable plant biomass","authors":"V. Kashparova, Daria V. Chernysheva, V. Klushin, Veronika E. Andreeva, O. A. Kravchenko, N. Smirnova","doi":"10.1070/RCR5018","DOIUrl":"https://doi.org/10.1070/RCR5018","url":null,"abstract":"Plant biomass is considered the main source of renewable carbon raw materials, which is a viable alternative to crude oil and natural gas and provides compounds with a low carbon footprint. The most promising direction for the conversion of biomass is the synthesis of 5-hydroxymethylfurfural, which is regarded as a platform chemical, the basis for the synthesis of valuable compounds, including monomers and polymers. The move of the polymer industry to renewable plant materials will contribute to solving global environmental problems and ensure the sustainability and environmental safety of plastics production. This review analyzes recent advances in the preparation of key C6-furan platform chemicals, such as 5-hydroxymethylfurfural, 2,5-furandicarboxylic acid, 2,5-diformylfuran, 2,5-bis(hydroxymethyl)furan, levulinic acid, and their use for the production of monomers and polymers based on renewable plant biomass. Production processes of widely known furan polyesters and polyamides, such as polyethylene-, polypropylene-, polybutylene furanoates, polyhexamethylene furanamide, are considered, as well as developments towards novel promising materials that are furan copolymers and polymer mixtures. For the first time, studies have been systematized aimed at converting liquid and solid wastes of the synthesis of platform chemicals, known as humins, into a range of value-added products, including organic compounds, porous carbon materials, thermosetting binders, and anticorrosive coatings that can replace similar materials based on fossil raw materials. Economic and environmental prospects and problems of production and consumption of furan polymers are considered. The bibliography includes 275 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49007608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This review generalizes diverse computational NMR studies of different natural products involving true alkaloids (indole, quinolizidine, pyrrolizidine, piperidine, indolizidine, quinoline, isoquinoline, indoloquinoline, and guanidine alkaloids), pseudoalkaloids (terpenes and steroids), quinones, lactones, lactams, flavonoids, and many others. The diverse computational protocols employed in each particular case are thoroughly discussed with a special emphasis on their structural and stereochemical applications. The bibliography includes 165 references.
{"title":"Computational NMR of natural products","authors":"V. Semenov, L. Krivdin","doi":"10.1070/RCR5027","DOIUrl":"https://doi.org/10.1070/RCR5027","url":null,"abstract":"This review generalizes diverse computational NMR studies of different natural products involving true alkaloids (indole, quinolizidine, pyrrolizidine, piperidine, indolizidine, quinoline, isoquinoline, indoloquinoline, and guanidine alkaloids), pseudoalkaloids (terpenes and steroids), quinones, lactones, lactams, flavonoids, and many others. The diverse computational protocols employed in each particular case are thoroughly discussed with a special emphasis on their structural and stereochemical applications. The bibliography includes 165 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43667258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Valeeva, A. Rempel, S. Rempel, S. Sadovnikov, A. Gusev
The results of recent experimental studies of the influence of the size of oxide, carbide and sulfide nanoparticles on changes in their nonstoichiometry are analyzed and generalized. In relation to intrinsically nonstoichiometric titanium oxides and niobium and vanadium carbides, on the one hand, and stoichiometric silver sulfides, on the other hand, it is shown that a decrease in the particle size to the nano scale has a strong impact on the chemical composition of nanocrystalline compounds, viz., it leads to the occurrence of or increase in nonstoichiometry. A conclusion is drawn that interplay between the particle size and nonstoichiometry is common to all solid nanocrystalline substances and should be taken into account in studies on the synthesis, structure and properties of these systems. The bibliography includes 260 references.
{"title":"Nonstoichiometry, structure and properties of nanocrystalline oxides, carbides and sulfides","authors":"A. Valeeva, A. Rempel, S. Rempel, S. Sadovnikov, A. Gusev","doi":"10.1070/RCR4967","DOIUrl":"https://doi.org/10.1070/RCR4967","url":null,"abstract":"The results of recent experimental studies of the influence of the size of oxide, carbide and sulfide nanoparticles on changes in their nonstoichiometry are analyzed and generalized. In relation to intrinsically nonstoichiometric titanium oxides and niobium and vanadium carbides, on the one hand, and stoichiometric silver sulfides, on the other hand, it is shown that a decrease in the particle size to the nano scale has a strong impact on the chemical composition of nanocrystalline compounds, viz., it leads to the occurrence of or increase in nonstoichiometry. A conclusion is drawn that interplay between the particle size and nonstoichiometry is common to all solid nanocrystalline substances and should be taken into account in studies on the synthesis, structure and properties of these systems. The bibliography includes 260 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47259697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The review presents data on the synthesis, structure, reactivity, and catalytic activity of alkyl derivatives of rare earth metals in the oxidation state +2 (Sm, Eu, Yb) and their analogues containing heavy alkaline earth metals (Ca, Sr, Ba). The synthetic aspects and structural features of this unique class of organometallic compounds, which contain highly reactive M–C bonds, including alkyl, α-silylmethyl, and also benzyl, diphenylmethyl, and triphenylmethyl derivatives are considered. The bibliography includes 157 references.
{"title":"Alkyl complexes of divalent lanthanides and heavy alkaline earth metals","authors":"D. Khristolyubov, D. Lyubov, A. Trifonov","doi":"10.1070/RCR4992","DOIUrl":"https://doi.org/10.1070/RCR4992","url":null,"abstract":"The review presents data on the synthesis, structure, reactivity, and catalytic activity of alkyl derivatives of rare earth metals in the oxidation state +2 (Sm, Eu, Yb) and their analogues containing heavy alkaline earth metals (Ca, Sr, Ba). The synthetic aspects and structural features of this unique class of organometallic compounds, which contain highly reactive M–C bonds, including alkyl, α-silylmethyl, and also benzyl, diphenylmethyl, and triphenylmethyl derivatives are considered. The bibliography includes 157 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47936790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The review aims to draw attention to the latest advances in the organoboron chemistry and therapeutic use of organoboron compounds. The synthetic strategies towards boron-containing compounds with proven in vitro and/or in vivo biological activities, including derivatives of boronic acids, benzoxaboroles, benzoxaborines and benzodiazaborines, are summarized. Approaches to the synthesis of hybrid structures containing an organoboron moiety as one of the pharmacophores are considered, and the effect of this modification on the pharmacological activity of the initial molecules is analyzed. On the basis of analysis of the published data, the most promising areas of research in the field of organoboron compounds are identified, including the latest methods of synthesis, modification and design of effective therapeutic agents. The bibliography includes 246 references.
{"title":"Progress in the medicinal chemistry of organoboron compounds","authors":"A. Tevyashova, M. Chudinov","doi":"10.1070/RCR4977","DOIUrl":"https://doi.org/10.1070/RCR4977","url":null,"abstract":"The review aims to draw attention to the latest advances in the organoboron chemistry and therapeutic use of organoboron compounds. The synthetic strategies towards boron-containing compounds with proven in vitro and/or in vivo biological activities, including derivatives of boronic acids, benzoxaboroles, benzoxaborines and benzodiazaborines, are summarized. Approaches to the synthesis of hybrid structures containing an organoboron moiety as one of the pharmacophores are considered, and the effect of this modification on the pharmacological activity of the initial molecules is analyzed. On the basis of analysis of the published data, the most promising areas of research in the field of organoboron compounds are identified, including the latest methods of synthesis, modification and design of effective therapeutic agents. The bibliography includes 246 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44803223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The revies focuses on low-molecular-weight plant metabolites (mono- and sesquiterpenes) exhibiting antiviral activity. Data on antiviral action of both essential oils and plant extracts and their components are provided. Structures of biologically active natural mono- and sesquiterpenoids as well as their derivatives showing a pronounced antiviral activity are presented. A special attention is given to the description of targets for antiviral therapy. The mechanisms of action of antiviral agents are considered. The bibliography includes 163 references.
{"title":"Mono- and sesquiterpenes as a starting platform for the development of antiviral drugs","authors":"O. Yarovaya, N. Salakhutdinov","doi":"10.1070/RCR4969","DOIUrl":"https://doi.org/10.1070/RCR4969","url":null,"abstract":"The revies focuses on low-molecular-weight plant metabolites (mono- and sesquiterpenes) exhibiting antiviral activity. Data on antiviral action of both essential oils and plant extracts and their components are provided. Structures of biologically active natural mono- and sesquiterpenoids as well as their derivatives showing a pronounced antiviral activity are presented. A special attention is given to the description of targets for antiviral therapy. The mechanisms of action of antiviral agents are considered. The bibliography includes 163 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47994479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The review summarizes and systematizes the [4+2]-cycloaddition reactions of o-quinone methides with electron-rich and electron-deficient olefins. The electron-rich substrates include vinyl ethers, vinyl sulfides, enamines, enamides, enols, furans, benzofurans and indoles, while the electron-deficient substrates are esters of unsaturated carboxylic acids, vinyl azides and quinones. Reactions with push-pull and captodative olefins are also considered. The mechanisms of some reactions are presented. A separate part of the review addresses reactions of p-quinone methides containing an o-hydroxyphenyl substituent at the exocyclic carbon atom, which can isomerize to o-quinone methides. Much attention is paid to oligomerization of o-quinone methides, which proceeds in the absence of active dienophiles or nucleophiles. The bibliography includes 217 references.
{"title":"Cycloaddition reactions of o-quinone methides with polarized olefins","authors":"V. Osyanin, A. V. Lukashenko, D. Osipov","doi":"10.1070/RCR4971","DOIUrl":"https://doi.org/10.1070/RCR4971","url":null,"abstract":"The review summarizes and systematizes the [4+2]-cycloaddition reactions of o-quinone methides with electron-rich and electron-deficient olefins. The electron-rich substrates include vinyl ethers, vinyl sulfides, enamines, enamides, enols, furans, benzofurans and indoles, while the electron-deficient substrates are esters of unsaturated carboxylic acids, vinyl azides and quinones. Reactions with push-pull and captodative olefins are also considered. The mechanisms of some reactions are presented. A separate part of the review addresses reactions of p-quinone methides containing an o-hydroxyphenyl substituent at the exocyclic carbon atom, which can isomerize to o-quinone methides. Much attention is paid to oligomerization of o-quinone methides, which proceeds in the absence of active dienophiles or nucleophiles. The bibliography includes 217 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42199831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For the first time, the literature data on the methods of synthesis and reactivity of 3-(1-alkynyl)chromones are summarized and systematized. The main method for obtaining these compounds is the Sonogashira cross-coupling reaction of 3-halochromones with terminal acetylenes, and their most important chemical properties include the transformation into furans, reactions with dinucleophiles, ambiphilic [4+2]- and [4+3]-cyclizations, and also dimerization and mixed condensation of 2-methyl-3-(1-alkynyl)chromones due to the vinylogous methyl group. Except for the oxacyclization to furans, chemical transformations of 3-(1-alkynyl)chromones are accompanied by pyrone ring transformation, in which not only the carbonyl group but also the triple bond can participate. This significantly increases the synthetic value of these compounds and ensures the production of more complex heterocyclic systems based on them. The mechanisms of the reactions are discussed, the conditions for their implementation and the yields of the resulting products are indicated. The bibliography includes 80 references.
{"title":"Synthesis and reactivity of 3-(1-alkynyl)chromones","authors":"V. Sosnovskikh","doi":"10.1070/RCR5008","DOIUrl":"https://doi.org/10.1070/RCR5008","url":null,"abstract":"For the first time, the literature data on the methods of synthesis and reactivity of 3-(1-alkynyl)chromones are summarized and systematized. The main method for obtaining these compounds is the Sonogashira cross-coupling reaction of 3-halochromones with terminal acetylenes, and their most important chemical properties include the transformation into furans, reactions with dinucleophiles, ambiphilic [4+2]- and [4+3]-cyclizations, and also dimerization and mixed condensation of 2-methyl-3-(1-alkynyl)chromones due to the vinylogous methyl group. Except for the oxacyclization to furans, chemical transformations of 3-(1-alkynyl)chromones are accompanied by pyrone ring transformation, in which not only the carbonyl group but also the triple bond can participate. This significantly increases the synthetic value of these compounds and ensures the production of more complex heterocyclic systems based on them. The mechanisms of the reactions are discussed, the conditions for their implementation and the yields of the resulting products are indicated. The bibliography includes 80 references.","PeriodicalId":21523,"journal":{"name":"Russian Chemical Reviews","volume":null,"pages":null},"PeriodicalIF":7.7,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49320018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}