In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude ran...In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude range10°≤l≤20° and the latitude strip of |b|≤ 5°. 25. The workflow for the extraction of clumps, namely Facet-SS-3DClump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3DClump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s^(-1). We observe a significant deviation of the mean Galactic latitude for clumps within |b|≤ 2° from the midplane, with b=-0°.110. We found that 82.3% of the dust clumps correspond to ^(13)CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect ^(13)CO clumps in the entire MWISP data.展开更多
Subclassification of tumors based on molecular features may facilitate therapeutic choice and increase the response rate of cancer patients.However,the highly complex cell origin involved in osteosarcoma(OS)limits the...Subclassification of tumors based on molecular features may facilitate therapeutic choice and increase the response rate of cancer patients.However,the highly complex cell origin involved in osteosarcoma(OS)limits the utility of traditional bulk RNA sequencing for OS subclassification.Single-cell RNA sequencing(sc RNA-seq)holds great promise for identifying cell heterogeneity.However,this technique has rarely been used in the study of tumor subclassification.By analyzing sc RNA-seq data for six conventional OS and nine cancellous bone(CB)samples,we identified 29 clusters in OS and CB samples and discovered three differentiation trajectories from the cancer stem cell(CSC)-like subset,which allowed us to classify OS samples into three groups.The classification model was further examined using the TARGET dataset.Each subgroup of OS had different prognoses and possible drug sensitivities,and OS cells in the three differentiation branches showed distinct interactions with other clusters in the OS microenvironment.In addition,we verified the classification model through IHC staining in 138 OS samples,revealing a worse prognosis for Group B patients.Furthermore,we describe the novel transcriptional program of CSCs and highlight the activation of EZH2 in CSCs of OS.These findings provide a novel subclassification method based on sc RNA-seq and shed new light on the molecular features of CSCs in OS and may serve as valuable references for precision treatment for and therapeutic development in OS.展开更多
In the study,it is proposed that a coordinate-parametric matrix model is performed to a square-conjoint pattern of cross woven(SCPCW)in the bamboo mat.The patterns of SCPCW are firstly detected according to the perspe...In the study,it is proposed that a coordinate-parametric matrix model is performed to a square-conjoint pattern of cross woven(SCPCW)in the bamboo mat.The patterns of SCPCW are firstly detected according to the perspective of configuration,which is divided into the basic-monomer shape and the basic combination shape.Secondly,the compositions of design patterns in SCPCW are analyzed to attain the trend of curve shape.Based on the coordinate-parametric matrix model,the specimens of SCPCW are subsequently accomplished to elaborate the woven logic of bamboo mats.The digital innovation of SCPCW,defined by a mathematical resolution,is implemented by the software of Grasshopper(GH),which plays a crucial role in capturing image information by the Image Sampler component.Successively,the weaving logic of coordinated matrix is referred to apply in the computing component of Grasshopper software.Finally,the computer simulation could demonstrate that the coordinate-parametric matrix model of SCPCWwould be realized to analyze the micro-weaving structure and overall weaving effect in the bamboo mat.展开更多
In this paper,the residue from bamboo factory has been used to design photo-Fenton catalyst,which has the advantages of low cost and magnetic recycling.The photo-Fenton catalytic performance of the biocarbon-based cat...In this paper,the residue from bamboo factory has been used to design photo-Fenton catalyst,which has the advantages of low cost and magnetic recycling.The photo-Fenton catalytic performance of the biocarbon-based catalyst was excellent and its optimal preparation process was also explored by response surface methodology.First,bamboo-carbon fiber was selected as the photo-Fenton catalyst carrier.Subsequently,the surface of the car-bon fiber was modified,with which dopamine,nano-Fe_(3)O_(4) and nano-TiO_(2) were successively loaded by hydro-thermal method.After the single factor tests,four factors including dopamine concentration,ferric chloride mass,P25 titanium dioxide mass and liquid-solid ratio were selected as the characteristic values.The degradation efficiency of photo-Fenton catalyst to methylene blue(MB)solution was treated as the response value.After the analysis of the response surface optimization,it was shown that the significance sequence of the selected 4 factors in terms of the MB degradation efficiency was arranged as follows:dopamine concentration>liquid-solid ratio>P25 titanium dioxide quality>ferric chloride quality.The optimal process parameters of fiber-carbon catalyst were affirmed as follows:the 1.7 mg/mL concentration of dopamine,the 1.2 g mass of ferric chloride,the 0.2 g mass of P25 titanium dioxide and the liquid-solid ratio of 170 mL/g.The experiment-measured average MB degra-dation efficiency performed by the optimized catalyst was 99.3%,which was nearly similar to the model-predicted value of 98.9%.It showed that the prediction model and response surface model were accurate and reliable.The results from response surface optimization could provide a good reference to design bamboo-based Fenton-like catalyst with excellent catalytic performance.展开更多
Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pel...Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pellegr.,Distemonanthus benthamianus and Erythrophleum ivorense A.Chev.The color of four wood species was evaluated to be consistent by the CIELab and CIE1931 color system.The boards of B.bracteosa,M.heitzii and E.ivorense was divided into dark color.The wood color of B.bracteosa had the highest red to green hue,while the wood appearance of D.benthamianus had the brightest and yellowest color within the four wood species.The whiteness of D.benthamianus was significantly higher than the other three wood species,namely tangential section 21.9%and radial section 22.2%.Hence,the color of the four species varied significantly,which was closely related to internal constituents of wood materials.M.heitzii wood had the highest surface glossiness on both tangential and radial section surfaces.The surface glossiness was highly related to the wood microstructure,especially with the pore and groove structure.This study of the visible characteristics provided the indicated knowledge for the application of the four wood species in wood industry.展开更多
Src homology 2 domain-containing tyrosine phosphatase 2(SHP2)is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth,differentiation,and survival.The ...Src homology 2 domain-containing tyrosine phosphatase 2(SHP2)is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth,differentiation,and survival.The activation of SHP2 has been shown to have a therapeutic effect in colitis and Parkinson's disease.Thus,the identification of SHP2 activators and a complete understanding of their mechanism is required.We used a two-step screening assay to determine a novel allosteric activator of SHP2 that stabilizes it in an open conformation.Oleanolic acid was identified as a suitable candidate.By binding to R362,K364,and K366 in the active center of the PTP domain,oleanolic acid maintained the active open state of SHP2,which facilitated the binding between SHP2 and its substrate.This oleanolic acid-activated SHP2 hindered Th17 differentiation by disturbing the interaction between STAT3 and IL-6Rαand inhibiting the activation of STAT3.Furthermore,via the activation of SHP2 and subsequent attenuation of the STAT3-Th17 axis,oleanolic acid effectively mitigated colitis in mice.This protective effect was abrogated by SHP2 knockout or administration of the SHP2 inhibitor SHP099.These findings underscore the potential of oleanolic acid as a promising therapeutic agent for treating inflammatory bowel diseases.展开更多
The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic synthesis.The organic chemistry textbook describes the classical reaction between an alkene and an iodine ele...The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic synthesis.The organic chemistry textbook describes the classical reaction between an alkene and an iodine electrophile(such as elemental iodine and N-iodosuccinimide(NIS))as a typical ionic reaction,in which an iodonium ion is formed and then attacked by a nucleophile.However,in this article,we report a new and unusual reaction mode between an alkene and NIS;that is,a single electron transfer(SET)process occurs between these two reactants by forming an electron-donor acceptor complex.Not only does this unusual single electron transfer reaction between an alkene and NIS add fundamentally important knowledge to organic chemistry,it also provides a valuable synthetic method as the new SET reaction mode with opposite regioselectivity as compared with the traditional ionic mode.展开更多
A general method for the synthesis of bench-stable bis(difluoromethyl)pentacoordinate phosphoranes has been developed.The reaction is rapid,operationally simple,and easily scalable.The pentacoordinate phosphoranes can...A general method for the synthesis of bench-stable bis(difluoromethyl)pentacoordinate phosphoranes has been developed.The reaction is rapid,operationally simple,and easily scalable.The pentacoordinate phosphoranes can generate both difluoromethyl radical(·CF_(2)H)and difluorocarbene(:CF_(2))intermediates.Thus,a variety of fluoroalkylation transformations havebeen achieved by·CF_(2)H,such asoxidativedifluoromethylation of electron-deficient heterocycles,nickel/photoredox dual-catalyzed difluoromethylation of aryl bromides,and photoredox difluoromethylation of alkenes,or by:CF_(2),such as gem-difluorocyclopropanation of alkenes,base-promoted difluoromethylation of heteroatom nucleophiles,Pd-catalyzed difluoromethylation of arylboronic acids,and Cu-mediated trifluoromethylation of aryl iodides(via:CF_(2) and recombined CF_(3)-).These fluoroalkylation methods have been successfully applied to late-stage fluoroalkylation of drugs and drug-like molecules.展开更多
The contributions of Professor Rolf Huisgen to organic chemistry are nu-merous.His research interests mainly focused on the organic reaction mechanism,1,3-dipolar cycloadditions,and orbital control of reactivity,among...The contributions of Professor Rolf Huisgen to organic chemistry are nu-merous.His research interests mainly focused on the organic reaction mechanism,1,3-dipolar cycloadditions,and orbital control of reactivity,among others.In the early days it was the chemistry of diazo compounds that attracted his interest.His group was able to increase the synthetic possibilities of this chemistry and to broaden the mechanistic knowledge about the reactions of diazo-and diazonium compounds.The reactions of N-nitrosoacylamides were studied in depth leading to formulation of al-kanediazonium ion pairs and the subsequent formation of carbocations in various product forming steps.展开更多
The divergent reductive cross-coupling with an ambident electrophile is rare.Previously,we demonstrated a nickel-catalyzed reductive 2-pyridination of aryl iodides with difluoromethyl 2-pyridyl sulfone(2-Py SO_(2)CF_(...The divergent reductive cross-coupling with an ambident electrophile is rare.Previously,we demonstrated a nickel-catalyzed reductive 2-pyridination of aryl iodides with difluoromethyl 2-pyridyl sulfone(2-Py SO_(2)CF_(2)H)via selective C(sp^(2))-S bond cleavage of the sulfone by using a phosphine ligand.In this communication,we report a novel nickel-catalyzed reductive coupling of aryl iodides and 2-Py SO_(2)CF_(2)H reagent,which constitutes a new method for aromatic difluoromethylation.The use of a tridentate terpyridine ligand is pivotal for the selective C(sp^(3))-S bond cleavage of the sulfone.This method employs readily available nickel catalyst and 2-Py SO_(2)CF_(2)H as the difluoromethylation reagent,providing a facile access to difluoromethylarenes under mild reaction conditions without pre-generation of arylmetal reagents.展开更多
A copper-mediated di- and monoffuoromethanesulfonylation of arenediazonium tetrafluoroborates using di- and monofluoromethanesul- finate reagents provides aryl difluoromethyl (or monofluoromethyl) sulfones in 8ood y...A copper-mediated di- and monoffuoromethanesulfonylation of arenediazonium tetrafluoroborates using di- and monofluoromethanesul- finate reagents provides aryl difluoromethyl (or monofluoromethyl) sulfones in 8ood yields. It was found that the relative reactivity of these sodium fluoroalkanesulfinates in the present reactions decreases in the followin8 order: CH2FSO2Na 〉 CF2HSO2Na 〉 CF3SO2Na.展开更多
Methyl fluorosulfonyldifluoroacetate(FSO2CF2CO2Me or MFSDA),often called"Chen's reagent",is commonly used to synthesize trifluoromethylated and difluoroalkylated compounds.This important reagent was init...Methyl fluorosulfonyldifluoroacetate(FSO2CF2CO2Me or MFSDA),often called"Chen's reagent",is commonly used to synthesize trifluoromethylated and difluoroalkylated compounds.This important reagent was initially developed as an efficient trifluoromethylating agent by Professor Qing-Yun Chen and co-workers at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences in 1989.展开更多
Wood-derived carbons have been demonstrated to have large specific capacities as the anode materials of lithium-ion batteries(LIBs). However, these carbons generally show low tap density and minor volumetric capacity ...Wood-derived carbons have been demonstrated to have large specific capacities as the anode materials of lithium-ion batteries(LIBs). However, these carbons generally show low tap density and minor volumetric capacity because of high specific surface area and pore volume. Combination with metal oxide is one of the expected methods to alleviate the obstacles of wood-derived carbons. In this work, the composites of Mn O loaded wood-derived carbon fibers(CF@Mn O) were prepared via a simple and environmentally friendly method, showing decreased specific surface area due to the generation of Mn O nanoparticles on carbon fibers. Furthermore, the CF@Mn O compostites exhibit superior electrochemical performance as anode materials of LIBs, which show high reversible capacity in the range of 529-734 m Ah/g at a current density of 100 m A/g. The optimal CF@Mn O product(Mn O:carbon = 1:2) delivers reversible capacity of 734 and 265.3 m Ah/g at current density of 100 and 2000 m A/g, respectively. Besides, the material presents outstanding stability with coulombic efficiency around 100% after 200 cycles at a high current density of 400 m A/g, revealing a potential as promising anode materials for high-performance LIBs.展开更多
Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity a...Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity and cycling stability of amorphous Co-B alloy nanoparticles grown on conductive graphene sheets. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. As electrode materials for pseudocapacitors, the amorphous Co-B alloy grown on graphene oxide (Co-B@GO) exhibits a high specific capacitance of 460 F g-1, which is nearly 1.5 times greater than that of bare Co-B nanoparticles at 1 A g-l, The specific capacitance preserved 84% of the initial capacitance even after 1000 cycles at a scan rate of 10 m V-1, suggesting its promising po- tential as pseudocapacitor materials.展开更多
A copper-mediated deuterotrifluoromethylation of α-diazo esters under the promotion of deuterium oxide (D20) has been developed for the synthesis of deuterium-labeled trifluoromethyl compounds. This deuterotrifluor...A copper-mediated deuterotrifluoromethylation of α-diazo esters under the promotion of deuterium oxide (D20) has been developed for the synthesis of deuterium-labeled trifluoromethyl compounds. This deuterotrifluoromethyl- ation reaction is of broad scope and can afford the deuterated products with higher than 99% isotopic purity. More- over, the results of this investigation also provide some experimental evidences to support our previously proposed trifluoromethylation mechanism.展开更多
An efficient nucleophilic difluoro(phenylsulfonimidoyl)methylation of unactivated primary alkyl bromides with PhSO(NTBS)CF_(2)H has been developed.It is particularly remarkable that,when 1.5 equiv.of alkyl bromides ar...An efficient nucleophilic difluoro(phenylsulfonimidoyl)methylation of unactivated primary alkyl bromides with PhSO(NTBS)CF_(2)H has been developed.It is particularly remarkable that,when 1.5 equiv.of alkyl bromides are used,the substitution products are obtained in moderate to excellent yields.The prepared difluoro(phenylsulfonimidoyl)methylated alkanes can be readily transformed to gem-difluoroalkenes via base-mediatedβ-elimination reaction.展开更多
Background and Originality Content Scheme I Aromatic pentafluoroethylation using TFE and CsF Perfluoroalkylated compounds are of great interest in pharmaceutical,agrochemical and material research and industry.[...Background and Originality Content Scheme I Aromatic pentafluoroethylation using TFE and CsF Perfluoroalkylated compounds are of great interest in pharmaceutical,agrochemical and material research and industry.[1]In this context,numerous efforts have been devoted to developing novel methods for the introduction of trifluoromethyl group(CF3)into organic aromatic compounds.[2]However,the similar pentafluoroethylation processes are still underexploited.[3] Currently available aromatic pentafluoroethylation methods mainly rely on transition-metal-mediated cross-coupling of aryl halides131 or aryl-boron compounds,141 and C-H functionalization of arenes.展开更多
An efficient trifluoromethylation reaction of vinyldiazoacetates under mild reaction conditions was depicted.Pre-generated CuCF_(3) was used as a trifluoromethylation reagent and water acted as both a promoter and pro...An efficient trifluoromethylation reaction of vinyldiazoacetates under mild reaction conditions was depicted.Pre-generated CuCF_(3) was used as a trifluoromethylation reagent and water acted as both a promoter and proton source.The reaction is compatible with a broad scope of functional groups and easy to scale-up.The wide functional group tolerance of the reaction enables further synthetic manipulation of the products.展开更多
1,1-Difluorinated sulfonamides are known to have better anti-inflammatory activity and enzyme inhibitory potency than their nonfluorinated counterparts.Two geminal fluorine atoms cause electronic perturbation of the n...1,1-Difluorinated sulfonamides are known to have better anti-inflammatory activity and enzyme inhibitory potency than their nonfluorinated counterparts.Two geminal fluorine atoms cause electronic perturbation of the nearby polar groups enhanced the biological activity of the 1,1-difluorinated sulfonamides.However,because methods for their stereoselective synthesis are scarce,such entities remain entirely unexplored.Here,we outline an efficient method for the stereoselective introduction of the difluoro(aminosulfonyl)methyl group(CF_(2)SO_(2)NH_(2))into carbonyls,imines,and alkyl halides with a new(R)-2-pyridyl difluoromethyl sulfoximine reagent,which provides a unique solution for the synthesis of chiralα,α-difluorinated sulfonamides with a quaternary stereocenter.Its potency is illustrated by the synthesis of fluorinated analogues of bioactive compounds such as 2-OH-SA,an antagonist for the GABA_(B)receptor in guinea pig ileum,and the late-stage modification of complex molecules such as haloperidol,ebastine,cholesterol,and(+)-δ-tocopherol derivatives.Stereoselective difluoro(aminosulfinyl)methylation to yield chiral sulfinylamides is presented,showcasing other uses of this new reagent.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.U2031202,11903083,11873093 and 12203029)sponsored by National Key R&D Program of China with grant 2017YFA0402701 and CAS Key Research Program of Frontier Sciences with grant QYZDJ-SSW-SLH047。
文摘In this study, we present a catalog of molecular clumps extracted from ^(13)CO(J=1-0) emission data of the Milky Way Imaging Scroll Painting(MWISP) project. The data covers the inner Milky Way within the longitude range10°≤l≤20° and the latitude strip of |b|≤ 5°. 25. The workflow for the extraction of clumps, namely Facet-SS-3DClump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3DClump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s^(-1). We observe a significant deviation of the mean Galactic latitude for clumps within |b|≤ 2° from the midplane, with b=-0°.110. We found that 82.3% of the dust clumps correspond to ^(13)CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect ^(13)CO clumps in the entire MWISP data.
基金National Natural Science Foundation of China(Nos.31970663 and 82173028 to J.X.,No.81874180 to T.W.,No.81201556 to W.Z.,No.82072971 to H.W.and No.81972505 to Z.W.)。
文摘Subclassification of tumors based on molecular features may facilitate therapeutic choice and increase the response rate of cancer patients.However,the highly complex cell origin involved in osteosarcoma(OS)limits the utility of traditional bulk RNA sequencing for OS subclassification.Single-cell RNA sequencing(sc RNA-seq)holds great promise for identifying cell heterogeneity.However,this technique has rarely been used in the study of tumor subclassification.By analyzing sc RNA-seq data for six conventional OS and nine cancellous bone(CB)samples,we identified 29 clusters in OS and CB samples and discovered three differentiation trajectories from the cancer stem cell(CSC)-like subset,which allowed us to classify OS samples into three groups.The classification model was further examined using the TARGET dataset.Each subgroup of OS had different prognoses and possible drug sensitivities,and OS cells in the three differentiation branches showed distinct interactions with other clusters in the OS microenvironment.In addition,we verified the classification model through IHC staining in 138 OS samples,revealing a worse prognosis for Group B patients.Furthermore,we describe the novel transcriptional program of CSCs and highlight the activation of EZH2 in CSCs of OS.These findings provide a novel subclassification method based on sc RNA-seq and shed new light on the molecular features of CSCs in OS and may serve as valuable references for precision treatment for and therapeutic development in OS.
基金financial support from the Hunan Provincial Key Research and Development Program(2020WK2018)the Arts Crafts Industrial Design Center of Hunan Province(No.2022GYMSZ2)the Scientific Innovation Fund for Post-Graduates of Central South University of Forestry and Technology(No.2022CX02079).
文摘In the study,it is proposed that a coordinate-parametric matrix model is performed to a square-conjoint pattern of cross woven(SCPCW)in the bamboo mat.The patterns of SCPCW are firstly detected according to the perspective of configuration,which is divided into the basic-monomer shape and the basic combination shape.Secondly,the compositions of design patterns in SCPCW are analyzed to attain the trend of curve shape.Based on the coordinate-parametric matrix model,the specimens of SCPCW are subsequently accomplished to elaborate the woven logic of bamboo mats.The digital innovation of SCPCW,defined by a mathematical resolution,is implemented by the software of Grasshopper(GH),which plays a crucial role in capturing image information by the Image Sampler component.Successively,the weaving logic of coordinated matrix is referred to apply in the computing component of Grasshopper software.Finally,the computer simulation could demonstrate that the coordinate-parametric matrix model of SCPCWwould be realized to analyze the micro-weaving structure and overall weaving effect in the bamboo mat.
基金funding from Hunan Provincial Key Research and Development Program(2020WK2018)Hunan Provincial Forestry Technological Innovation Funds(XLK202107-3)+2 种基金Scientific Research Project of Hunan Education Department(19A505,21B0242)National Natural Science Foundation of China(No.21908251)Hunan Provincial Natural Science Foundation of China(No.2020JJ2058).
文摘In this paper,the residue from bamboo factory has been used to design photo-Fenton catalyst,which has the advantages of low cost and magnetic recycling.The photo-Fenton catalytic performance of the biocarbon-based catalyst was excellent and its optimal preparation process was also explored by response surface methodology.First,bamboo-carbon fiber was selected as the photo-Fenton catalyst carrier.Subsequently,the surface of the car-bon fiber was modified,with which dopamine,nano-Fe_(3)O_(4) and nano-TiO_(2) were successively loaded by hydro-thermal method.After the single factor tests,four factors including dopamine concentration,ferric chloride mass,P25 titanium dioxide mass and liquid-solid ratio were selected as the characteristic values.The degradation efficiency of photo-Fenton catalyst to methylene blue(MB)solution was treated as the response value.After the analysis of the response surface optimization,it was shown that the significance sequence of the selected 4 factors in terms of the MB degradation efficiency was arranged as follows:dopamine concentration>liquid-solid ratio>P25 titanium dioxide quality>ferric chloride quality.The optimal process parameters of fiber-carbon catalyst were affirmed as follows:the 1.7 mg/mL concentration of dopamine,the 1.2 g mass of ferric chloride,the 0.2 g mass of P25 titanium dioxide and the liquid-solid ratio of 170 mL/g.The experiment-measured average MB degra-dation efficiency performed by the optimized catalyst was 99.3%,which was nearly similar to the model-predicted value of 98.9%.It showed that the prediction model and response surface model were accurate and reliable.The results from response surface optimization could provide a good reference to design bamboo-based Fenton-like catalyst with excellent catalytic performance.
基金This work was financially supported by the Hunan Provincial Natural Science Foundation of China(2020JJ2058)Scientific Research Foundation of Hunan Provincial Education Department(18A159)Technology Innovation Project of Yihua Lifestyle Technology Co.,Ltd.(YH-JSJSKF-201708006).
文摘Color,whiteness and glossiness of four caesalpiniaceae wood species were characterized by quantitative measurements and image analysis,i.e.,which were respectively Berlinia bracteosa Benth.,Monopetalanthus heitzii Pellegr.,Distemonanthus benthamianus and Erythrophleum ivorense A.Chev.The color of four wood species was evaluated to be consistent by the CIELab and CIE1931 color system.The boards of B.bracteosa,M.heitzii and E.ivorense was divided into dark color.The wood color of B.bracteosa had the highest red to green hue,while the wood appearance of D.benthamianus had the brightest and yellowest color within the four wood species.The whiteness of D.benthamianus was significantly higher than the other three wood species,namely tangential section 21.9%and radial section 22.2%.Hence,the color of the four species varied significantly,which was closely related to internal constituents of wood materials.M.heitzii wood had the highest surface glossiness on both tangential and radial section surfaces.The surface glossiness was highly related to the wood microstructure,especially with the pore and groove structure.This study of the visible characteristics provided the indicated knowledge for the application of the four wood species in wood industry.
基金supported by the National Natural Science Foundation of China(82173820,82073856,82273933)Fundamental Research Funds for the Central Universities(020814380160,China)+1 种基金Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(ZYYCXTD-C-202208,China)the Young Scholar Foundation from Cyrus Tang Foundation(China).
文摘Src homology 2 domain-containing tyrosine phosphatase 2(SHP2)is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth,differentiation,and survival.The activation of SHP2 has been shown to have a therapeutic effect in colitis and Parkinson's disease.Thus,the identification of SHP2 activators and a complete understanding of their mechanism is required.We used a two-step screening assay to determine a novel allosteric activator of SHP2 that stabilizes it in an open conformation.Oleanolic acid was identified as a suitable candidate.By binding to R362,K364,and K366 in the active center of the PTP domain,oleanolic acid maintained the active open state of SHP2,which facilitated the binding between SHP2 and its substrate.This oleanolic acid-activated SHP2 hindered Th17 differentiation by disturbing the interaction between STAT3 and IL-6Rαand inhibiting the activation of STAT3.Furthermore,via the activation of SHP2 and subsequent attenuation of the STAT3-Th17 axis,oleanolic acid effectively mitigated colitis in mice.This protective effect was abrogated by SHP2 knockout or administration of the SHP2 inhibitor SHP099.These findings underscore the potential of oleanolic acid as a promising therapeutic agent for treating inflammatory bowel diseases.
基金supported by National Key Research and Development Program of China(2021YFF0701700)the National Natural Science Foundationof China(22271299 and 22261132514).
文摘The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic synthesis.The organic chemistry textbook describes the classical reaction between an alkene and an iodine electrophile(such as elemental iodine and N-iodosuccinimide(NIS))as a typical ionic reaction,in which an iodonium ion is formed and then attacked by a nucleophile.However,in this article,we report a new and unusual reaction mode between an alkene and NIS;that is,a single electron transfer(SET)process occurs between these two reactants by forming an electron-donor acceptor complex.Not only does this unusual single electron transfer reaction between an alkene and NIS add fundamentally important knowledge to organic chemistry,it also provides a valuable synthetic method as the new SET reaction mode with opposite regioselectivity as compared with the traditional ionic mode.
基金supported by National Natural Science Foundation of China(grant no.21901196)the Natural Science Basic Research Plan in Shaanxi Province of China(grant nos.2020JQ-016 and 2021GXLH-Z-096)+1 种基金the Fundamental Research Funds for the Central Universities(grant no.xhj032021007-01)Xi’an Jiaotong University(grant no.71211920000001).
文摘A general method for the synthesis of bench-stable bis(difluoromethyl)pentacoordinate phosphoranes has been developed.The reaction is rapid,operationally simple,and easily scalable.The pentacoordinate phosphoranes can generate both difluoromethyl radical(·CF_(2)H)and difluorocarbene(:CF_(2))intermediates.Thus,a variety of fluoroalkylation transformations havebeen achieved by·CF_(2)H,such asoxidativedifluoromethylation of electron-deficient heterocycles,nickel/photoredox dual-catalyzed difluoromethylation of aryl bromides,and photoredox difluoromethylation of alkenes,or by:CF_(2),such as gem-difluorocyclopropanation of alkenes,base-promoted difluoromethylation of heteroatom nucleophiles,Pd-catalyzed difluoromethylation of arylboronic acids,and Cu-mediated trifluoromethylation of aryl iodides(via:CF_(2) and recombined CF_(3)-).These fluoroalkylation methods have been successfully applied to late-stage fluoroalkylation of drugs and drug-like molecules.
文摘The contributions of Professor Rolf Huisgen to organic chemistry are nu-merous.His research interests mainly focused on the organic reaction mechanism,1,3-dipolar cycloadditions,and orbital control of reactivity,among others.In the early days it was the chemistry of diazo compounds that attracted his interest.His group was able to increase the synthetic possibilities of this chemistry and to broaden the mechanistic knowledge about the reactions of diazo-and diazonium compounds.The reactions of N-nitrosoacylamides were studied in depth leading to formulation of al-kanediazonium ion pairs and the subsequent formation of carbocations in various product forming steps.
基金supported by the National Key Research and Development Program of China(2021YFF0701700)the National Natural Science Foundation of China(22271299,22261132514)+1 种基金the Natural Science Foundation of Shandong Province(ZR2021LFG006)the State Key Laboratory of Fluorine-Containing Functional Membrane Materials。
文摘The divergent reductive cross-coupling with an ambident electrophile is rare.Previously,we demonstrated a nickel-catalyzed reductive 2-pyridination of aryl iodides with difluoromethyl 2-pyridyl sulfone(2-Py SO_(2)CF_(2)H)via selective C(sp^(2))-S bond cleavage of the sulfone by using a phosphine ligand.In this communication,we report a novel nickel-catalyzed reductive coupling of aryl iodides and 2-Py SO_(2)CF_(2)H reagent,which constitutes a new method for aromatic difluoromethylation.The use of a tridentate terpyridine ligand is pivotal for the selective C(sp^(3))-S bond cleavage of the sulfone.This method employs readily available nickel catalyst and 2-Py SO_(2)CF_(2)H as the difluoromethylation reagent,providing a facile access to difluoromethylarenes under mild reaction conditions without pre-generation of arylmetal reagents.
基金Acknowledgement This work was supported by the National Key Research and Development Program of China (2015CB931900, 2016YFB0101200), the National Natural Science Foundation of China (21632009, 21421002, 21472221, 21372246, 21302206), the Key Programs of the Chinese Academy of Sciences (KGZD-EW- TO8), the Key Research Program of Frontier Sciences of CAS (O.YZDJ-SSW-SLH049), Shanghai Science and Technology program (15XD1504400), and Youth Innovation Promotion Association CAS (2014231).
文摘A copper-mediated di- and monoffuoromethanesulfonylation of arenediazonium tetrafluoroborates using di- and monofluoromethanesul- finate reagents provides aryl difluoromethyl (or monofluoromethyl) sulfones in 8ood yields. It was found that the relative reactivity of these sodium fluoroalkanesulfinates in the present reactions decreases in the followin8 order: CH2FSO2Na 〉 CF2HSO2Na 〉 CF3SO2Na.
基金the National Basic Research Program of China(Nos.2015CB931900,2016YFB0101200)the National Natural Science Foundation of China(Nos.21632009,21421002)+2 种基金the Key Programs of the Chinese Academy of Sciences(No.KGZD-EWT08)the Key Research Program of Frontier Sciences of CAS(No.QYZDJ-SSW-SLH049)Shanghai Science and Technology Program(No.18JC1410601)is acknowledged。
文摘Methyl fluorosulfonyldifluoroacetate(FSO2CF2CO2Me or MFSDA),often called"Chen's reagent",is commonly used to synthesize trifluoromethylated and difluoroalkylated compounds.This important reagent was initially developed as an efficient trifluoromethylating agent by Professor Qing-Yun Chen and co-workers at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences in 1989.
基金financially supported by the Hunan Provincial Natural Science Foundation of China (No.2020JJ2058)Forestry science and technology innovation of Hunan Province (No.XLK202107-3)+2 种基金Scientific Research Foundation of Hunan Provincial Education Department (No.18A159)Scientific Research Foundation of Central South University of Forestry and Technology (Nos.104–0452,2018YC003)the National Natural Science Foundation of China (No.52073064)。
文摘Wood-derived carbons have been demonstrated to have large specific capacities as the anode materials of lithium-ion batteries(LIBs). However, these carbons generally show low tap density and minor volumetric capacity because of high specific surface area and pore volume. Combination with metal oxide is one of the expected methods to alleviate the obstacles of wood-derived carbons. In this work, the composites of Mn O loaded wood-derived carbon fibers(CF@Mn O) were prepared via a simple and environmentally friendly method, showing decreased specific surface area due to the generation of Mn O nanoparticles on carbon fibers. Furthermore, the CF@Mn O compostites exhibit superior electrochemical performance as anode materials of LIBs, which show high reversible capacity in the range of 529-734 m Ah/g at a current density of 100 m A/g. The optimal CF@Mn O product(Mn O:carbon = 1:2) delivers reversible capacity of 734 and 265.3 m Ah/g at current density of 100 and 2000 m A/g, respectively. Besides, the material presents outstanding stability with coulombic efficiency around 100% after 200 cycles at a high current density of 400 m A/g, revealing a potential as promising anode materials for high-performance LIBs.
基金supported by the University of Minnesota Initiative for Renewable Energy and the Environment(IREE)the Shanghai Municipal Education Commission(High-energy Beam Intelligent Processing and Green Manufacturing)the Characterization Facility,University of Minnesota,which receives partial support from NSF through the MRSEC program
文摘Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduc- tion approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity and cycling stability of amorphous Co-B alloy nanoparticles grown on conductive graphene sheets. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. As electrode materials for pseudocapacitors, the amorphous Co-B alloy grown on graphene oxide (Co-B@GO) exhibits a high specific capacitance of 460 F g-1, which is nearly 1.5 times greater than that of bare Co-B nanoparticles at 1 A g-l, The specific capacitance preserved 84% of the initial capacitance even after 1000 cycles at a scan rate of 10 m V-1, suggesting its promising po- tential as pseudocapacitor materials.
基金the National Key Research and Development Program of China (Nos.2015CB931900, 2016YFB0101200)the National Natural Science Foundation of China (Nos.21632009,21421002,21472221)+2 种基金the Key Programs of the Chinese Academy of Sciences (No.KGZD-EW-T08)the Key Research Program of Frontier Sciences of CAS (No.QYZDJ-SSW-SLH049)Shanghai Science and Technology program (No. 16QA1404600).
文摘A copper-mediated deuterotrifluoromethylation of α-diazo esters under the promotion of deuterium oxide (D20) has been developed for the synthesis of deuterium-labeled trifluoromethyl compounds. This deuterotrifluoromethyl- ation reaction is of broad scope and can afford the deuterated products with higher than 99% isotopic purity. More- over, the results of this investigation also provide some experimental evidences to support our previously proposed trifluoromethylation mechanism.
基金Support of our work by the National Basic Research Program of China(Nos.2012CB215500 and 2012CB821600)the NNSFC(No.21372246)+1 种基金Shanghai QMX program(No.13QH1402400)the Chinese Academy of Sciences is gratefully acknowledged.
文摘An efficient nucleophilic difluoro(phenylsulfonimidoyl)methylation of unactivated primary alkyl bromides with PhSO(NTBS)CF_(2)H has been developed.It is particularly remarkable that,when 1.5 equiv.of alkyl bromides are used,the substitution products are obtained in moderate to excellent yields.The prepared difluoro(phenylsulfonimidoyl)methylated alkanes can be readily transformed to gem-difluoroalkenes via base-mediatedβ-elimination reaction.
基金This work was supported by the National Basic Research Program of China(Nos.2015CB931900,2012CB215500)the National Natural Science Foundation of China(Nos.21632009,21421002)+2 种基金the Key Program of the Chinese Academy of Sciences(No.KGZD-EW-T08)the Key Research Program of Frontier Sciences of CAS(No.QYZDJ-SSWSLH049)the Shanghai Rising-Star Program(No.16QA1404600)for financial support.
文摘Background and Originality Content Scheme I Aromatic pentafluoroethylation using TFE and CsF Perfluoroalkylated compounds are of great interest in pharmaceutical,agrochemical and material research and industry.[1]In this context,numerous efforts have been devoted to developing novel methods for the introduction of trifluoromethyl group(CF3)into organic aromatic compounds.[2]However,the similar pentafluoroethylation processes are still underexploited.[3] Currently available aromatic pentafluoroethylation methods mainly rely on transition-metal-mediated cross-coupling of aryl halides131 or aryl-boron compounds,141 and C-H functionalization of arenes.
基金the National Natural Science Foundation of China(21901196)the Natural Science Basic Research Plan in Shaanxi Province of China(2020JQ-016)Xi’an Jiaotong University(71211920000001)for financial support.
文摘An efficient trifluoromethylation reaction of vinyldiazoacetates under mild reaction conditions was depicted.Pre-generated CuCF_(3) was used as a trifluoromethylation reagent and water acted as both a promoter and proton source.The reaction is compatible with a broad scope of functional groups and easy to scale-up.The wide functional group tolerance of the reaction enables further synthetic manipulation of the products.
基金Financial support was provided by the National Key Research and Development Program of China(no.2016YFB0101200)the National Natural Science Foundation of China(no.21632009)+2 种基金the Key Programs of CAS(no.KGZD-EW-T08)the Key Research Program of Frontier Sciences of CAS(no.QYZDJ-SSW-SLH049)Shanghai Science and Technology Program(no.16QA1404600).
文摘1,1-Difluorinated sulfonamides are known to have better anti-inflammatory activity and enzyme inhibitory potency than their nonfluorinated counterparts.Two geminal fluorine atoms cause electronic perturbation of the nearby polar groups enhanced the biological activity of the 1,1-difluorinated sulfonamides.However,because methods for their stereoselective synthesis are scarce,such entities remain entirely unexplored.Here,we outline an efficient method for the stereoselective introduction of the difluoro(aminosulfonyl)methyl group(CF_(2)SO_(2)NH_(2))into carbonyls,imines,and alkyl halides with a new(R)-2-pyridyl difluoromethyl sulfoximine reagent,which provides a unique solution for the synthesis of chiralα,α-difluorinated sulfonamides with a quaternary stereocenter.Its potency is illustrated by the synthesis of fluorinated analogues of bioactive compounds such as 2-OH-SA,an antagonist for the GABA_(B)receptor in guinea pig ileum,and the late-stage modification of complex molecules such as haloperidol,ebastine,cholesterol,and(+)-δ-tocopherol derivatives.Stereoselective difluoro(aminosulfinyl)methylation to yield chiral sulfinylamides is presented,showcasing other uses of this new reagent.