In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using at...In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.展开更多
In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mi...In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.展开更多
A strategy for copper-catalyzed and biphosphine ligand controlled boracarboxylation of 1,3-dienes and CO_(2) with 3,4-selectivity was developed.The Cu Cl coupled with DPPF(1,1-bis(diphenylphosphino)ferrocene)was assig...A strategy for copper-catalyzed and biphosphine ligand controlled boracarboxylation of 1,3-dienes and CO_(2) with 3,4-selectivity was developed.The Cu Cl coupled with DPPF(1,1-bis(diphenylphosphino)ferrocene)was assigned to be the best catalyst,with 84%yield and exclusive3,4-selectivity.The ligand effect on both catalytic activity and regioselectivity of boracarboxylation was disclosed,which is rarely reported in any copper catalyzed boracarboxylation.The borocupration process is revealed to be a vital step for the biphosphine participated boracarboxylation of 1,3-dienes with CO_(2).The minimal substrate distortion occurring in 3,4-borocupration favors the 3,4-regioselectivity of boracarboxylation.The“pocket”confinement and suitableβ_(n)(92°–106°)of bisphosphine ligands are demonstrated to be in favour of the interaction between LCu-Bpin complex(the catalytic precursor)and1,3-diene substrate to decrease their interaction energyΔE_(int)(ζ)in 3,4-borocupration,thus promoting the 3,4-boracarboxylation.展开更多
Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron d...Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.展开更多
The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed...The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.展开更多
Bay-site carboxyl functionalized perylene diimide derivative 1,7-COOH-PDI-C_(12)(PDI-COOH)was synthesized and distinct enhanced fluorescence was observed through combining with calcium ion(Ca^(2+))in THF/H_(2)O soluti...Bay-site carboxyl functionalized perylene diimide derivative 1,7-COOH-PDI-C_(12)(PDI-COOH)was synthesized and distinct enhanced fluorescence was observed through combining with calcium ion(Ca^(2+))in THF/H_(2)O solution.The assembly and fluorescence behavior of PDI-COOH/Ca^(2+)were studied in detail by changing hydration state with different concentrations.Based on the differences in assembly morphology and stoichiometric ratios of PDICOOH/Ca^(2+),we proposed the fluorescence emission mechanism of PDI-COOH/Ca^(2+)in THF/H_(2)O and THF,respectively.This work reveals a novel strategy of aggregated state fluorescence enhancement and reminds us of the important role of water in molecular fluorescence emission and assembly.展开更多
An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acylox...An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acyloxy esters in moderate to high yields with a broad substrate scope.All starting materials are readily available,and the reactions can be conducted in the open air at room temperature.展开更多
Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidate...Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidated.Under optimal conditions,the addition of AEC-9Na with a mass fraction of 0.03% can enhance the leaching rate by 5.2% and reduce the leaching cycle.Kinetic analysis demonstrates that the leaching process follows the model of internal diffusion control.The analysis of the mass transfer process reveals that the addition of AEC-9Na results in a decrease in the height equivalent to a theoretical plate(HETP)and an improvement in mass transfer efficiency.The addition of AEC-9Na can reduce the thickness of the water layer adsorbed on particles during leaching,which in turn reduces hydration and facilitates penetration of the leaching solution into ore body pores.This improves mass transfer concentration differences during leaching,and facilitates desorption of rare earth ions.Periodic density functional theory(DFT)calculations show that the adsorption of AEC-9Na onto the surface of kaolinite(001)enhances the hydrophilicity of the mineral surface and improves its permeability efficiency.Simultaneously,AEC-9Na forms complexes with hydrated rare earth ions on the kaolinite(001)surface,thereby reducing their adsorption strength on clay minerals.This promotes the exchange and desorption process of magnesium ions to hydrated rare earth ions,ultimately enhancing the mass transfer process for leaching rare earth elements.展开更多
To improve the low-temperature performances of Li-ion cells, three types of linear carboxylic ester-based electrolyte, such as EC/EMC/EA（1：1：2, mass ratio）, EC/EMC/EP（1：1：2, mass ratio） and EC/EMC/EB（1：1：2,...To improve the low-temperature performances of Li-ion cells, three types of linear carboxylic ester-based electrolyte, such as EC/EMC/EA（1：1：2, mass ratio）, EC/EMC/EP（1：1：2, mass ratio） and EC/EMC/EB（1：1：2, mass ratio）, were prepared to substitute for industrial electrolyte（EC/EMC/DMC）. Then, 18650-type Li Mn2O4-graphite cells（nominal capacity of 1150 mA ·h） were assembled and studied. Results show that the cells containing three types of electrolyte are able to undertake 5C discharging current with above 93% capacity retention at-20 °C. Electrochemical impedance spectra show that the discharge capacity fading of Li-ion cells at low temperature is mainly ascribed to the charge transfer resistance increasing with temperature decreasing. In comparison, the cells containing electrolyte of 1.0 mol/L LiPF6 in EC/EMC/EA（1：1：2, mass ratio） have the highest capacity retention of 90% at-40 °C and 44.41% at-60 °C, due to its lowest charge-transfer resistance.展开更多
Carbon dioxide is a cheap, abundant and renewable C1 building block. Over the last two decades, considerable re- search efforts have been devoted to developing new reactions for the efficient incorporation of carbon d...Carbon dioxide is a cheap, abundant and renewable C1 building block. Over the last two decades, considerable re- search efforts have been devoted to developing new reactions for the efficient incorporation of carbon dioxide into a broad range of compounds for the production of value-added materi- als [1]. Notably, these efforts have culminated in the develop- ment of several transition-metal-catalyzed methods capable of providing access to numerous synthetically important carbox- ylic acids and derivatives using carbon dioxide as a carboxyla- tive reagent [2].展开更多
Two new l-（6＇-O-acyl-β-D-glucopyranosyl）pyridinium-3-carboxylates,lonijaponinicotinosides A（1）and B（2）,were isolated from an aqueous extract of the flower buds of Lonicera japonica.Their structures were determ...Two new l-（6＇-O-acyl-β-D-glucopyranosyl）pyridinium-3-carboxylates,lonijaponinicotinosides A（1）and B（2）,were isolated from an aqueous extract of the flower buds of Lonicera japonica.Their structures were determined by spectroscopic data analysis,and confirmed by comparison with synthetic 1-β-Dglucopyranosylpyridinium-3-carboxylate.展开更多
Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic dens...Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.展开更多
Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good ...Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields(32%–91%).In addition,a gram-scale reaction,late-stage modification of drug,synthetic transformation of the product,and further application of the catalytic strategy were also performed.Preliminary studies indicate that the reaction undergoes a radical process.展开更多
Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methy...Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.展开更多
In a scale-up microbial transformation of（–）-huperzine A（1） by Streptomyces griseus CACC 200300, a specific carboxylated derivative（2） was yielded together with two known hydroxylated metabolites. The structure...In a scale-up microbial transformation of（–）-huperzine A（1） by Streptomyces griseus CACC 200300, a specific carboxylated derivative（2） was yielded together with two known hydroxylated metabolites. The structure of 2 was characterized as 16-carboxyl huperzine A on the basis of IR, HRMS and NMR spectroscopic data analysis.展开更多
Electrocarboxylation of anthrone in the presence of CO2 to anthrance-9-carboxylic acid directly was carried out. The electroreduction behavior of anthrone was examined by cyclic voltammetry in the absence and presence...Electrocarboxylation of anthrone in the presence of CO2 to anthrance-9-carboxylic acid directly was carried out. The electroreduction behavior of anthrone was examined by cyclic voltammetry in the absence and presence of CO2. Then the influences of the supporting electrolytes, temperature, electrode material and anthrone concentration on the carboxylation yield were investigated. Under the optimized conditions, anthrancene-9-carboxylic acid was obtained in a good yield（96.1%）.展开更多
A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） w...A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ~H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu4Sn2O2 unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exocyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good anti- bacterial and antitumour activities.展开更多
Manganese（Ⅲ） meso-tetraphenylporphyrin acetate [Mn（TPP）OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with （diacetoxyiodo）benzene [PhI（OAc）2] in CH2CI2-H2O（95：5, ...Manganese（Ⅲ） meso-tetraphenylporphyrin acetate [Mn（TPP）OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with （diacetoxyiodo）benzene [PhI（OAc）2] in CH2CI2-H2O（95：5, volume ratio）. The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn（TPP）OAc. In the former case, the formation of carbonyl products was complete within just a few minutes with 〉97% selectivities, and no further oxidation of the produced aldehydes was achieved under these catalytic conditions. This method provides a benign procedure owing to the utilization of low toxic（diacetoxyiodo） benzene, biologically relevant manganese porphyrins, and carboxylic acids.展开更多
As an attractive C1 synthon,carbon dioxide(CO_(2))has been extensively used in organic synthesis to produce carboxylic acids.In this research,stereoselective electrochemical carboxylation ofα,β-unsaturated sulfones ...As an attractive C1 synthon,carbon dioxide(CO_(2))has been extensively used in organic synthesis to produce carboxylic acids.In this research,stereoselective electrochemical carboxylation ofα,β-unsaturated sulfones has been developed under transition-metal-free conditions.All the cinnamic acids and the derivatives are obtained selectively in the E-configuration.Besides,arylpropiolates also can be produced from alkynyl sulfones.展开更多
Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were ef...Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.展开更多
文摘In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.
基金Financial support from National Key R&D Program of China (No.2023YFA1507203)National Natural Science Foundation of China (Nos.22371149 and 22188101)+3 种基金the Fundamental Research Funds for the Central Universities (No.63224098)Frontiers Science Center for New Organic Matter,Nankai University (No.63181206)Nankai University are gratefully acknowledgedthe Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.
基金the National Key R&D Program of China(No.2022YFB4101900)National Natural Science Foundation of China(Nos.22278305,U21B2096)Natural Science Foundation of Tianjin City(No.23JCZDJC00040)。
文摘A strategy for copper-catalyzed and biphosphine ligand controlled boracarboxylation of 1,3-dienes and CO_(2) with 3,4-selectivity was developed.The Cu Cl coupled with DPPF(1,1-bis(diphenylphosphino)ferrocene)was assigned to be the best catalyst,with 84%yield and exclusive3,4-selectivity.The ligand effect on both catalytic activity and regioselectivity of boracarboxylation was disclosed,which is rarely reported in any copper catalyzed boracarboxylation.The borocupration process is revealed to be a vital step for the biphosphine participated boracarboxylation of 1,3-dienes with CO_(2).The minimal substrate distortion occurring in 3,4-borocupration favors the 3,4-regioselectivity of boracarboxylation.The“pocket”confinement and suitableβ_(n)(92°–106°)of bisphosphine ligands are demonstrated to be in favour of the interaction between LCu-Bpin complex(the catalytic precursor)and1,3-diene substrate to decrease their interaction energyΔE_(int)(ζ)in 3,4-borocupration,thus promoting the 3,4-boracarboxylation.
基金supported by the National Key R&D Program of China(No.2022YFC2105301)the National Natural Science Foundation of China(No.52270096).
文摘Microbial consortia that catalyze chain elongation processes have been enriched using different selection strategies,for which the electron donor is an essential one.Propanol is an extraordinarily promising electron donor because it can be generated from renewable resources,including lignocellulosic biomass and protein wastes.Here,propanol was proven in detail to be an efficient electron donor,enhancing the production of odd medium-chain carboxylates during chain elongation.By exploring various electron acceptors,reactor conditions,and electron donor/electron acceptor mol ratios,our study highlights that acetate is the most suitable electron acceptor for the production of both odd-and even-chain carboxylates.The optimal conditions for propanol-based chain elongation were 30℃ and pH 6,achieving 82.8%selectivity for odd-chain carboxylates.Another critical insight from our work is that a propanol/acetate mol ratio of 1:1 can minimize the inhibitory effect of propanol and maximize the yield of medium-chain carboxylates,with the highest concentration of n-heptanoate reaching 124.5 mmol C/L.This was further illustrated by 16S rRNA amplicon sequencing,which elucidated that the community composition and keystone species in a propanol-based reactor closely resembled that of the ethanol one.The dominant phylum of the propanol-based reactor,Firmicutes showed a significant positive correlation with the concentrations of n-caproate and n-valerate.Additionally,the co-occurrence of Clostridium sensu stricto 12 and Oscillibacter,known as typical chain elongators,was identified within the propanol-based reactor.These findings enhance our understanding of propanolbased chain elongation,offer guiding principles for reactor microbiota assembly,and support efficient odd medium-chain carboxylate production.
基金supported by the National Natural Science Foundation of China,Nos.91849115 and U1904207(to YX),81974211 and 82171247(to CS)Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences,No.2020-PT310-01(to YX).
文摘The E3 ubiquitin ligase,carboxyl terminus of heat shock protein 70(Hsp70)interacting protein(CHIP),also functions as a co-chaperone and plays a crucial role in the protein quality control system.In this study,we aimed to investigate the neuroprotective effect of overexpressed CHIP on Alzheimer’s disease.We used an adeno-associated virus vector that can cross the blood-brain barrier to mediate CHIP overexpression in APP/PS1 mouse brain.CHIP overexpression significantly ameliorated the performance of APP/PS1 mice in the Morris water maze and nest building tests,reduced amyloid-βplaques,and decreased the expression of both amyloid-βand phosphorylated tau.CHIP also alleviated the concentration of microglia and astrocytes around plaques.In APP/PS1 mice of a younger age,CHIP overexpression promoted an increase in ADAM10 expression and inhibitedβ-site APP cleaving enzyme 1,insulin degrading enzyme,and neprilysin expression.Levels of HSP70 and HSP40,which have functional relevance to CHIP,were also increased.Single nuclei transcriptome sequencing in the hippocampus of CHIP overexpressed mice showed that the lysosomal pathway and oligodendrocyte-related biological processes were up-regulated,which may also reflect a potential mechanism for the neuroprotective effect of CHIP.Our research shows that CHIP effectively reduces the behavior and pathological manifestations of APP/PS1 mice.Indeed,overexpression of CHIP could be a beneficial approach for the treatment of Alzheimer’s disease.
文摘Bay-site carboxyl functionalized perylene diimide derivative 1,7-COOH-PDI-C_(12)(PDI-COOH)was synthesized and distinct enhanced fluorescence was observed through combining with calcium ion(Ca^(2+))in THF/H_(2)O solution.The assembly and fluorescence behavior of PDI-COOH/Ca^(2+)were studied in detail by changing hydration state with different concentrations.Based on the differences in assembly morphology and stoichiometric ratios of PDICOOH/Ca^(2+),we proposed the fluorescence emission mechanism of PDI-COOH/Ca^(2+)in THF/H_(2)O and THF,respectively.This work reveals a novel strategy of aggregated state fluorescence enhancement and reminds us of the important role of water in molecular fluorescence emission and assembly.
文摘An efficient TfOH-catalyzed O—H insertion reaction of α-aryl diazoesters with carboxylic acids is reported.This metal-free protocol provides an operationally simple method for a one-pot assembly of diverse α-acyloxy esters in moderate to high yields with a broad substrate scope.All starting materials are readily available,and the reactions can be conducted in the open air at room temperature.
基金Project supported by the National Natural Science Foundation Regional Innovation Development Joint Fund(U24A2096)。
文摘Surfactant sodium alcohol ether carboxylate(AEC-9Na)was added to the magnesium sulfate solution in order to enhance the leaching efficiency of ionic rare earth ore,and the mechanism of action for AEC-9Na was elucidated.Under optimal conditions,the addition of AEC-9Na with a mass fraction of 0.03% can enhance the leaching rate by 5.2% and reduce the leaching cycle.Kinetic analysis demonstrates that the leaching process follows the model of internal diffusion control.The analysis of the mass transfer process reveals that the addition of AEC-9Na results in a decrease in the height equivalent to a theoretical plate(HETP)and an improvement in mass transfer efficiency.The addition of AEC-9Na can reduce the thickness of the water layer adsorbed on particles during leaching,which in turn reduces hydration and facilitates penetration of the leaching solution into ore body pores.This improves mass transfer concentration differences during leaching,and facilitates desorption of rare earth ions.Periodic density functional theory(DFT)calculations show that the adsorption of AEC-9Na onto the surface of kaolinite(001)enhances the hydrophilicity of the mineral surface and improves its permeability efficiency.Simultaneously,AEC-9Na forms complexes with hydrated rare earth ions on the kaolinite(001)surface,thereby reducing their adsorption strength on clay minerals.This promotes the exchange and desorption process of magnesium ions to hydrated rare earth ions,ultimately enhancing the mass transfer process for leaching rare earth elements.
基金Project(2007BAE12B01)supported by the National Key Technology Research and Development Program of ChinaProject(20803095)supported by the National Natural Science Foundation of China
文摘To improve the low-temperature performances of Li-ion cells, three types of linear carboxylic ester-based electrolyte, such as EC/EMC/EA（1：1：2, mass ratio）, EC/EMC/EP（1：1：2, mass ratio） and EC/EMC/EB（1：1：2, mass ratio）, were prepared to substitute for industrial electrolyte（EC/EMC/DMC）. Then, 18650-type Li Mn2O4-graphite cells（nominal capacity of 1150 mA ·h） were assembled and studied. Results show that the cells containing three types of electrolyte are able to undertake 5C discharging current with above 93% capacity retention at-20 °C. Electrochemical impedance spectra show that the discharge capacity fading of Li-ion cells at low temperature is mainly ascribed to the charge transfer resistance increasing with temperature decreasing. In comparison, the cells containing electrolyte of 1.0 mol/L LiPF6 in EC/EMC/EA（1：1：2, mass ratio） have the highest capacity retention of 90% at-40 °C and 44.41% at-60 °C, due to its lowest charge-transfer resistance.
文摘Carbon dioxide is a cheap, abundant and renewable C1 building block. Over the last two decades, considerable re- search efforts have been devoted to developing new reactions for the efficient incorporation of carbon dioxide into a broad range of compounds for the production of value-added materi- als [1]. Notably, these efforts have culminated in the develop- ment of several transition-metal-catalyzed methods capable of providing access to numerous synthetically important carbox- ylic acids and derivatives using carbon dioxide as a carboxyla- tive reagent [2].
基金Financial support from the National Natural Science Foundation of China(NNSFCNos.20772156 and 30825044)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT,No.IRT1007)the National Science and Technology Project of China(Nos.2012ZX09301002-002 and 2011ZX0 9307-002-01)
文摘Two new l-（6＇-O-acyl-β-D-glucopyranosyl）pyridinium-3-carboxylates,lonijaponinicotinosides A（1）and B（2）,were isolated from an aqueous extract of the flower buds of Lonicera japonica.Their structures were determined by spectroscopic data analysis,and confirmed by comparison with synthetic 1-β-Dglucopyranosylpyridinium-3-carboxylate.
基金the State Key Laboratory of Silicate Materials for Architectures(SYSJJ2018-09)the Shaanxi Provincial High Performance Concrete Engineering Laboratory(SHPC201701)
文摘Molecular structures of polycarboxylate（PCE） superplasticizer significantly affect the rheological properties of cement paste. Consequently, we employed self-synthesized PCE copolymers with different carboxylic densities to investigate their influence on the rheological behavior of cement paste. Three typical rheological models were applied to analyze the rheological properties, including Power-law model, Bingham model as well as Herschel-Buikley model. In addition, the thixotropical performances of cement paste in the presence of PCE with different carboxylic densities were investigated. The results show that the carboxylic density of PCE greatly influences the dispersing performance of PCE superplasticizers. As carboxylic density increases, the dispersing capability of PCE improves, and P（PEG1-AA6） possesses the strongest dispersing capability, the initial fluidity and 1 h fluidity of cement paste are both the highest, and cement paste has the lowest viscosity and the smallest hysteresis loop.
基金financially supported by the National Natural Science Foundation of China(Nos.21402116,21502111,21572126)the Science and Technology Innovation Talents of Henan Province(No.2018JQ0011)the Key Science Research of Education Committee in Henan Province(No.21A150044)。
文摘Silver-catalyzed decarboxylative C–H alkylation of cyclic aldimines with abundant aliphatic carboxylic acids has been realized under mild reaction conditions generating the corresponding products in moderate to good yields(32%–91%).In addition,a gram-scale reaction,late-stage modification of drug,synthetic transformation of the product,and further application of the catalytic strategy were also performed.Preliminary studies indicate that the reaction undergoes a radical process.
文摘Two new phenolic carboxylic acid esters n-butyl eucomate(1) and methyl eucomate (2) and six known compounds eucomic acid(3), 3-β-acetyl-taraxerol (4), friedelin(5),lupenone(6),methyl linoleate(7) and methyl oleate(8) were isolated from the stems of Opuntia vulgaris Mill(Cactaceae). Their structures were determined on the basis of spectral methods. Compounds 3,4,6,7,8 were isolated for the first time from this plant.
基金National Natural Science Foundation of China(Grant No.81072541)
文摘In a scale-up microbial transformation of（–）-huperzine A（1） by Streptomyces griseus CACC 200300, a specific carboxylated derivative（2） was yielded together with two known hydroxylated metabolites. The structure of 2 was characterized as 16-carboxyl huperzine A on the basis of IR, HRMS and NMR spectroscopic data analysis.
基金Supported by the National Natural Science Foundation of China(No.20973065)the"Chen Guang"Project Supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation,China(No.10CG26)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20100076120020)the Foundation of Outstanding Yong Talent in University of Anhui Province,China(No.2010SQRL042)
文摘Electrocarboxylation of anthrone in the presence of CO2 to anthrance-9-carboxylic acid directly was carried out. The electroreduction behavior of anthrone was examined by cyclic voltammetry in the absence and presence of CO2. Then the influences of the supporting electrolytes, temperature, electrode material and anthrone concentration on the carboxylation yield were investigated. Under the optimized conditions, anthrancene-9-carboxylic acid was obtained in a good yield（96.1%）.
基金Supported by the National Natural Science Foundation of China(No.2005038561)Natural Science Foundation of Province,China(Nos.20060571 and 20070406)
文摘A novel macrocyclic complex 2{[（n-Bu2Sn）4O2-L2]2DMF} was synthesized by the reaction of 4-（1,2- dithioethylene）methylene-3,5-disoxo-1,6-heptadiene-1,7-dis-（o-formy~）-dis-p-phenoxyacetic acid（LH2, compound 1） with di-n-butyltin oxide. Compound 1 and complex 2 were characterized by elemental analysis, FTIR spectroscopy, and ~H NMR spectroscopy. The crystal structure of complex 2 was determined by single crystal X-ray diffraction analysis. There are two crystallographic independent molecules in complex 2, and each molecule structure is centro-symmetric and features a central rhombus cyclic Bu4Sn2O2 unit with two exocyclic Sn atoms linked at the O atoms of the four-membered ring. In molecule A, the four Sn atoms are five-coordinated. However, in molecule B, the four Sn atoms have two different coordination geometries, the endocyclic Sn atoms are five-coordinated and the exocyclic Sn atoms are four-coordinated. The dicarboxylate ligands in molecules A and B bridge exocylic or endocyclic tin atoms, forming two macroheterocycles with 26 atoms. Pilot studies have indicated that complex 2 has good anti- bacterial and antitumour activities.
文摘Manganese（Ⅲ） meso-tetraphenylporphyrin acetate [Mn（TPP）OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with （diacetoxyiodo）benzene [PhI（OAc）2] in CH2CI2-H2O（95：5, volume ratio）. The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn（TPP）OAc. In the former case, the formation of carbonyl products was complete within just a few minutes with 〉97% selectivities, and no further oxidation of the produced aldehydes was achieved under these catalytic conditions. This method provides a benign procedure owing to the utilization of low toxic（diacetoxyiodo） benzene, biologically relevant manganese porphyrins, and carboxylic acids.
基金Financial support from the National Natural Science Foundation of China(No.21901041)the Fuzhou University(No.0041/511095)。
文摘As an attractive C1 synthon,carbon dioxide(CO_(2))has been extensively used in organic synthesis to produce carboxylic acids.In this research,stereoselective electrochemical carboxylation ofα,β-unsaturated sulfones has been developed under transition-metal-free conditions.All the cinnamic acids and the derivatives are obtained selectively in the E-configuration.Besides,arylpropiolates also can be produced from alkynyl sulfones.
基金supported by National 863 High-Tech Research and Development Program of China(No.2007AA05Z101).
文摘Ionic liquids [Bmim]BF4 and [Bpy]BF4 were employed as environmentally benign media in Doebner condensation to synthesize α, β-unsaturated carboxylic acid. The good results showed that [Bmim]BF4 and [Bpy]BF4 were efficient media for Doebner condensation, which could be recycled easily. The highest yields could reach 93% and 90% in [Bmim]BF4 and [Bpy]BF4, respectively.
