New sustainable syntheses based on solid-state strategies have sparked enormous attention and provided novel routes for the synthesis of supported metallic alloy nanocatalysts(SMACs).Despite considerable recent progre...New sustainable syntheses based on solid-state strategies have sparked enormous attention and provided novel routes for the synthesis of supported metallic alloy nanocatalysts(SMACs).Despite considerable recent progress in this field,most of the developed methods suffer from either complex operations or poorly controlled morphology,which seriously limits their practical applications.Here,we have developed a sustainable strategy for the synthesis of PdAg alloy nanoparticles(NPs)with an ultrafine size and good dispersion on various carbon matrices by directly grinding the precursors in an agate mortar at room temperature.Interestingly,no solvents or organic reagents are used in the synthesis procedure.This simple and green synthesis procedure provides alloy NPs with clean surfaces and thus an abundance of accessible active sites.Based on the combination of this property and the synergistic and alloy effects between Pd and Ag atoms,which endow the NPs with high intrinsic activity,the PdAg/C samples exhibit excellent activities as electrocatalysts for both the hydrogen oxidation and evolution reactions(HOR and HER)in a basic medium.Pd9Ag1/C showed the highest activity in the HOR with the largest j0,m value of 26.5 A g Pd^–1 and j0,s value of 0.033 mA cmPd^–2,as well as in the HER,with the lowest overpotential of 68 mV at 10 mA cm^–2.As this synthetic method can be easily adapted to other systems,the present scalable solid-state strategy may open opportunity for the general synthesis of a wide range of well-defined SMACs for diverse applications.展开更多
Electrochemical performances of LiCoO_2 as a candidate material for supercapacitor are systematically investigated. LiCoO_2 nanomaterials are synthesized via hydrothermal reaction with consequent calcination process. ...Electrochemical performances of LiCoO_2 as a candidate material for supercapacitor are systematically investigated. LiCoO_2 nanomaterials are synthesized via hydrothermal reaction with consequent calcination process. And the particle size increases as the calcination temperature rises. LCO-650 sample with the largest particle size displays the maximum capacitances of 817.5 F·g^-1 with the most outstanding capacity retention rate of 96.8% after 2000 cycles. It is shown that large particle size is beneficial to the electrochemical and structural stability of LiCoO_2 materials. We speculate that the micron-sized waste LiCoO_2 materials have great potential for supercapacitor application. It may provide a novel recovered approach for spent LIBs and effectively relieve the burdens on the resource waste and environment pollution.展开更多
[ Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluc- tuation zone of the Three Gorges Reservoir. [ Method] A. calamus plants were exp...[ Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluc- tuation zone of the Three Gorges Reservoir. [ Method] A. calamus plants were exposed to water under the dark conditions respectively in Septem- ber 2009 and September 2010. Then, they were taken away from the water, and grew in natural conditions in the following March and April respec- tively ( marked as S1, S2, S1 and S2). The plant number was conducted statistics respectively. On May 7, the leaf number was made statistics. Length, width and rapid light responding curve of the leaf were determined. [ Result] Repeated flooding restrained significantly plant germination un- der the dark condition. Plant number in S1 and S2 groups decreased by 38.9% and 33.3% respectively compared with the control. It also reduced survival rate of the plant. Plant number in S2 group decreased by 16.7% (P 〈 0.05) compared with that of S2 group when they were taken away from the water. Both of flooding promoted elongation of the leaves, restrained leaves to grow wider, and also restrained leaf formation of the plants except for S1 and S1 groups. Total leaf length of a plant decreased markedly after the second flooding which in S1 and S2 groups were 50.6% and 36.9% respectively less than that after the first flooding. Total leaf number of the plant in S1and S2 groups reduced significantly, and they were only 63.1% and 38.5% respectively of the control. Compared with the first flooding, total leaf length of a plant in the control increased signifi- cantly and decreased remarkably in S2 group after the second flooding. Furthermore, light response ability of the relative electronic transfer rate (rETR) in S1 group wasn't significantly different from the control, and rETRmax, in S2 group was significantly less than the control. Moreover, non- photochemical quenching (NPQ) decreased remarkably in S1 and S2 groups. It indicated that A. calamus had good restore ability of the light re- sponse, but restoring of its heat dissipation capacity was slower. [ Conclusion] Repeated flooding inhibited plant growth and population recovery of A. calamus under the dark condition.展开更多
The semi-continuous seeded emulsion eopolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship b...The semi-continuous seeded emulsion eopolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship between the reaction time and the average particle diameter and/or the conversion ratio during the polymerization were invstiguted. The experimental results shaw that the morphology of the latex particle possesses the stable sterie construction. In the seeded polymerizution, the average particle diameter of latex decreased while the conversion ratio increased. At the second term of the emulsion copolymerization (the growth stage of particle size), the latex particle average diameter increased with copolymerization continuously, but the instantaneous conversation ratio was not large, so it was very necessaO to properly prolong the time during the holding temperature stage.展开更多
Nonporous and porous C/PLA/nano-HA composites were fabricated by the process of solvent blending and freeze-drying technique, and the effect of porous structure on the mechanical properties of C/PLA/nano-HA composites...Nonporous and porous C/PLA/nano-HA composites were fabricated by the process of solvent blending and freeze-drying technique, and the effect of porous structure on the mechanical properties of C/PLA/nano-HA composites scaffold was investigated and analyzed. The results show that the effects of porous structure on the bending strength, modulus and curves of stress and strain were obvious. Compared with nonporous sample, the curves of stress and strain of porous sample show more rough, and alternative phenomenon of stress increase and stress relaxation appears. It is strongly suggested that the fracture model of C/PLA/nano-HA composites scaffold transforms from the local to global load due to the porous structure.展开更多
The main characteristics, applications, the emphases of manufacturing process are introduced, and the research of new product of rigid-flex Printed Circuit Board (PCB) is also described. In particular, the plasma de...The main characteristics, applications, the emphases of manufacturing process are introduced, and the research of new product of rigid-flex Printed Circuit Board (PCB) is also described. In particular, the plasma desmear process, which is the crucial problems of manufacturing process, is discussed in detail. Samsung 4-layer rigid-flex PCB has been developed successfully, and the qualification rate reaches to 89.4%.展开更多
In this paper, the activities of electrophilic sites on benzene ring of 4-substituted anilines and their acyl compounds were studied with the quantitative indicator of multiphilicity descriptor. Four substituents were...In this paper, the activities of electrophilic sites on benzene ring of 4-substituted anilines and their acyl compounds were studied with the quantitative indicator of multiphilicity descriptor. Four substituents were synthe- sized with microwave irradiation in good yields to verify the quantitative analysis data. Friedel-Crafts acylation was carried out by the microwave method for the first time.展开更多
Graphene sponge(GS) is a porous 3D structure of graphene. Although hydrothermal reduction, chemical vapor deposition, solution reduction and high temperature annealing could be used for the preparation of GS, the size...Graphene sponge(GS) is a porous 3D structure of graphene. Although hydrothermal reduction, chemical vapor deposition, solution reduction and high temperature annealing could be used for the preparation of GS, the size and shape cannot be well controlled. Herein, we reported a facile method to prepare GS under mild condition in a size and shape controllable way. Graphene oxide was lyophilized to form the spongy structure and reduced by steamy hydrazine hydrate to produce GS. The size and shape of GS prepared were nearly identical to that of the container. The reduction degree of GS could be regulated by the reduction temperature and time.展开更多
This review summarizes the recent advances in the catalytic syntheses of CFS-containing organic molecules using various nucleophilic or electrophilic trifluoromethylthiolating reagents.C-halogen and C—H bonds in vari...This review summarizes the recent advances in the catalytic syntheses of CFS-containing organic molecules using various nucleophilic or electrophilic trifluoromethylthiolating reagents.C-halogen and C—H bonds in various molecules have been transformed to C—SCFbonds by transition-metal-catalyzed reactions,such as cross-coupling of aryl halides.Enantioselective reactions controlled by chiral metal complexes or chiral organocatalysts have afforded many trifluoromethylthiolated chiral architectures,such as β-ketoesters and oxindoles.Very recently,visible-light-induced photoredox trifluoromethylthiolations have been developed,providing versatile CFS-containing structures efficiently.展开更多
Graphene/polyester staple sponge(GPSS)is a high-performance adsorbent for the cleanup of crude oil spill,but the use of hydrazine hydrate as the reducing agent for the preparation of GPSS is not friendly to the enviro...Graphene/polyester staple sponge(GPSS)is a high-performance adsorbent for the cleanup of crude oil spill,but the use of hydrazine hydrate as the reducing agent for the preparation of GPSS is not friendly to the environment.Herein,we reported that graphene oxide/polyester staple composite could be hydrothermally reduced by bioresource glucose to prepare GPSS of similar performance.GPSS could be applied in the absorption of oils and organic solvents thanks to its large pore volume and hydrophobicity.The absorption capacity of the novel glucose-reduced GPSS was competitive to those of the most effective absorbents for oil spill cleanup.The used GPSS could be easily regenerated by soaking in ethanol to remove the absorbed oil.The green synthesis,high oil absorption performance and easy recycling of the glucose-reduced GPSS make it a good candidate for cleaning oil spills.展开更多
An attempt was made to test the validity of the signatures of rare earth elements (REE) as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments fro...An attempt was made to test the validity of the signatures of rare earth elements (REE) as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments from Jinsha Relics, Sichuan, Southwest China were analyzed. The difference in REE content between fossil teeth is significantly greater than that between sediments at the Jinsha Relics. Chondrite-normalized REE patterns showed that obvious LREE enrichment and strong Ce and HREE depletion occurred in all fossil teeth samples. Meanwhile δCe and δEu values varied more dramatically in fossil teeth than in sediments. Accordingly, low content, LREE enrichment, strong Ce depletion, the significantly positive correlation between LREE/HREE and δCe, and unchanged (La/Yb)N demonstrated that the fossil teeth from Jinsha Relics have not been contaminated by diagenesis. The REE signature might be a potential proxy to assess the effect of diagenesis on fossil teeth.展开更多
Chemical reaction possibility was described quantitatively for the case of nitrotriazolam preparation with 2-clonazepam by using the data of two quantum chemical reactivity indices: net electrophilicity index and Wibe...Chemical reaction possibility was described quantitatively for the case of nitrotriazolam preparation with 2-clonazepam by using the data of two quantum chemical reactivity indices: net electrophilicity index and Wiberg bond order. Furthennore, relevant reaction mechanism was derived from tlie aspect of quantum chemistry. The results show that the indices used can quantitatively explain the chemical reactivity and reaction mechanism of the nitrotriazolam preparation. To validate the universal applicability of the proposed approach, the authors continued to use the quantum chemical reactivity indices to describe some classic chemical reactions, expecting to predict major issues related to physical organic chemistry, such as new chemical reactions and their mechanisms.展开更多
The cytochrome P450 (Cyt-P450) proteins from the fat body and midgut of the cotton bollworm, Helicoverpa armigera, were respectively partially purified by a set of purification procedures including differential cent...The cytochrome P450 (Cyt-P450) proteins from the fat body and midgut of the cotton bollworm, Helicoverpa armigera, were respectively partially purified by a set of purification procedures including differential centrifugation, solubilization of CHAPS, protein precipitation by PEG precipitation and DE-32 column chromatography. The CytP450 was detected by methods of CO difference spectrum and SDS-PAGE. Fraction of detergent solubilized microsomes from the fat body of H. armigera was purified more than 17-fold. Three protein bands were detected by SDS-PAGE with molecular masses of 70 600, 63 300 and 571 200Da. It is possible that the proteins with molecular mass of 63 300 and 571 200Da were the isozymes of Cyt-P450.展开更多
A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolys...A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.展开更多
2-Amino-3-nitrile-chromenes with potential antitumor activity were constructed by a novel catalytic system. In combination with a-naphthol, quinine could effectively promote the Michael-cyclization process of malononi...2-Amino-3-nitrile-chromenes with potential antitumor activity were constructed by a novel catalytic system. In combination with a-naphthol, quinine could effectively promote the Michael-cyclization process of malononitrile with functionalized chalcones in high yields and moderate to good enantioselectivity(up to 84% ee). It is notable that the enantioselectivity could be greatly improved when a-naphthol was employed as additive.展开更多
A novel organocatalytic cascade process initiated by 1,6-conjugated addition has been successfully developed. A range of pharmaceutically active 2-amino-4-aryl-4H-chromenes were readily obtained in high yields(88%-99...A novel organocatalytic cascade process initiated by 1,6-conjugated addition has been successfully developed. A range of pharmaceutically active 2-amino-4-aryl-4H-chromenes were readily obtained in high yields(88%-99%) and excellent enantiopurities(86%-99% ee). The functionalized para-Quinone methides(p-OMs) could be facilely obtained.展开更多
Water pollution has become serious environmental problem nowadays. Advanced oxidation processes(AOP) have been widely applied in water treatment.However, traditional Fenton reaction based on Fe2﹢-H2O2 system has obvi...Water pollution has become serious environmental problem nowadays. Advanced oxidation processes(AOP) have been widely applied in water treatment.However, traditional Fenton reaction based on Fe2﹢-H2O2 system has obvious drawbacks, which limit its applications In this study, magnetic Fe3O4core-C shell nanoparticles(Fe3O4@C NPs) were prepared for the decoloration of methylene blue(MB) via the co-precipitation followed by the hydrothermal dehydrogenation of glucose. Fe3O4@C NPs showed high catalytic activity of the decoloration of MB through the decomposition of H2O2 in Fenton-like reactions. Fe3O4@C NPs had much higher activity than bare Fe3O4 cores, suggesting the coating of carbon enhanced the catalytic activity. The performance of Fe3O4@C NPs was better at lower pH and higher temperature, but was significantly inhibited in the presence of radical scavenger tertiary butanol. Fe3O4@C NPs could be magnetic separated and regenerated, and maintained with very good catalytic activity. The implication for the applications of Fe3O4@C NP-catalyzed Fenton-like reactions in water treatment was discussed.展开更多
A desirable near-infrared(NIR)photothermal agent based on Mo-based polyoxometalate cluster with self-adaptive electronic structure for tumor acidity/reducibility-specific therapy was reported in a paper on Journal of ...A desirable near-infrared(NIR)photothermal agent based on Mo-based polyoxometalate cluster with self-adaptive electronic structure for tumor acidity/reducibility-specific therapy was reported in a paper on Journal of the American Chemical Society[1].This‘‘small-big"cluster paradigm displayed the capacity of self-assemble to big molecules under activation both the展开更多
Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modif...Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modification could be used as Fenton-like catalysts. Surface doping of Ti O2 could concentrate the pollutants surrounding the Fe3O4 catalyst, which might benefit the catalytic performance of Fe3O4. Herein, we reported that Ti O2-doped Fe3O4 nanoparticles(NPs) could be used as high-performance Fenton-like catalyst for dye decoloration in near neutral environment, where the doping of Ti O2 on Fe3O4 surface dramatically improved the catalytic activity of Fe3O4 in Fenton-like reaction. Ti O2-doped Fe3O4 NPs catalyzed the decomposition of H2O2 to oxidize methylene blue without external energy supply, resulting in effective decoloration. Ti O2-doped Fe3O4 NPs showed high catalytic activity under various p H values and even in the presence of radical scavenger. More catalysts and H2O2 would facilitate the decoloration. At higher temperature, the decoloration became faster and more effective. The implication to the environmental applications of Ti O2-doped Fe3O4 NPs is discussed.展开更多
文摘New sustainable syntheses based on solid-state strategies have sparked enormous attention and provided novel routes for the synthesis of supported metallic alloy nanocatalysts(SMACs).Despite considerable recent progress in this field,most of the developed methods suffer from either complex operations or poorly controlled morphology,which seriously limits their practical applications.Here,we have developed a sustainable strategy for the synthesis of PdAg alloy nanoparticles(NPs)with an ultrafine size and good dispersion on various carbon matrices by directly grinding the precursors in an agate mortar at room temperature.Interestingly,no solvents or organic reagents are used in the synthesis procedure.This simple and green synthesis procedure provides alloy NPs with clean surfaces and thus an abundance of accessible active sites.Based on the combination of this property and the synergistic and alloy effects between Pd and Ag atoms,which endow the NPs with high intrinsic activity,the PdAg/C samples exhibit excellent activities as electrocatalysts for both the hydrogen oxidation and evolution reactions(HOR and HER)in a basic medium.Pd9Ag1/C showed the highest activity in the HOR with the largest j0,m value of 26.5 A g Pd^–1 and j0,s value of 0.033 mA cmPd^–2,as well as in the HER,with the lowest overpotential of 68 mV at 10 mA cm^–2.As this synthetic method can be easily adapted to other systems,the present scalable solid-state strategy may open opportunity for the general synthesis of a wide range of well-defined SMACs for diverse applications.
基金supported by the Scientific Research Fund of Hunan Provincial Science & Technology Department(2012FJ3023)the Research Fund for the Doctroral Program of Higher Education of China(20120031110001)
文摘Electrochemical performances of LiCoO_2 as a candidate material for supercapacitor are systematically investigated. LiCoO_2 nanomaterials are synthesized via hydrothermal reaction with consequent calcination process. And the particle size increases as the calcination temperature rises. LCO-650 sample with the largest particle size displays the maximum capacitances of 817.5 F·g^-1 with the most outstanding capacity retention rate of 96.8% after 2000 cycles. It is shown that large particle size is beneficial to the electrochemical and structural stability of LiCoO_2 materials. We speculate that the micron-sized waste LiCoO_2 materials have great potential for supercapacitor application. It may provide a novel recovered approach for spent LIBs and effectively relieve the burdens on the resource waste and environment pollution.
基金Supported by Natural Science Foundation Project,Chongqing Science and Technology Commission(CSTC) ,China(2009BB7255)Talent Start-up Foundation Project ,Chongqing University of Arts and Science,ChinaScience Research Project,Chongqing University of Arts and Science(XZ031)
文摘[ Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluc- tuation zone of the Three Gorges Reservoir. [ Method] A. calamus plants were exposed to water under the dark conditions respectively in Septem- ber 2009 and September 2010. Then, they were taken away from the water, and grew in natural conditions in the following March and April respec- tively ( marked as S1, S2, S1 and S2). The plant number was conducted statistics respectively. On May 7, the leaf number was made statistics. Length, width and rapid light responding curve of the leaf were determined. [ Result] Repeated flooding restrained significantly plant germination un- der the dark condition. Plant number in S1 and S2 groups decreased by 38.9% and 33.3% respectively compared with the control. It also reduced survival rate of the plant. Plant number in S2 group decreased by 16.7% (P 〈 0.05) compared with that of S2 group when they were taken away from the water. Both of flooding promoted elongation of the leaves, restrained leaves to grow wider, and also restrained leaf formation of the plants except for S1 and S1 groups. Total leaf length of a plant decreased markedly after the second flooding which in S1 and S2 groups were 50.6% and 36.9% respectively less than that after the first flooding. Total leaf number of the plant in S1and S2 groups reduced significantly, and they were only 63.1% and 38.5% respectively of the control. Compared with the first flooding, total leaf length of a plant in the control increased signifi- cantly and decreased remarkably in S2 group after the second flooding. Furthermore, light response ability of the relative electronic transfer rate (rETR) in S1 group wasn't significantly different from the control, and rETRmax, in S2 group was significantly less than the control. Moreover, non- photochemical quenching (NPQ) decreased remarkably in S1 and S2 groups. It indicated that A. calamus had good restore ability of the light re- sponse, but restoring of its heat dissipation capacity was slower. [ Conclusion] Repeated flooding inhibited plant growth and population recovery of A. calamus under the dark condition.
文摘The semi-continuous seeded emulsion eopolymerization of vinyl acetate and butyl acrylate was carried out with hydroxyethyl cellulose as a colloid stabilizer. The morphology of the latex particle and the relationship between the reaction time and the average particle diameter and/or the conversion ratio during the polymerization were invstiguted. The experimental results shaw that the morphology of the latex particle possesses the stable sterie construction. In the seeded polymerizution, the average particle diameter of latex decreased while the conversion ratio increased. At the second term of the emulsion copolymerization (the growth stage of particle size), the latex particle average diameter increased with copolymerization continuously, but the instantaneous conversation ratio was not large, so it was very necessaO to properly prolong the time during the holding temperature stage.
基金Project(30870609) supported by the National Natural Science Foundation of ChinaProjects(KJ081205 KJ091213) supported by the Natural Science Foundation of Chongqing Education Committee, China
文摘Nonporous and porous C/PLA/nano-HA composites were fabricated by the process of solvent blending and freeze-drying technique, and the effect of porous structure on the mechanical properties of C/PLA/nano-HA composites scaffold was investigated and analyzed. The results show that the effects of porous structure on the bending strength, modulus and curves of stress and strain were obvious. Compared with nonporous sample, the curves of stress and strain of porous sample show more rough, and alternative phenomenon of stress increase and stress relaxation appears. It is strongly suggested that the fracture model of C/PLA/nano-HA composites scaffold transforms from the local to global load due to the porous structure.
文摘The main characteristics, applications, the emphases of manufacturing process are introduced, and the research of new product of rigid-flex Printed Circuit Board (PCB) is also described. In particular, the plasma desmear process, which is the crucial problems of manufacturing process, is discussed in detail. Samsung 4-layer rigid-flex PCB has been developed successfully, and the qualification rate reaches to 89.4%.
文摘In this paper, the activities of electrophilic sites on benzene ring of 4-substituted anilines and their acyl compounds were studied with the quantitative indicator of multiphilicity descriptor. Four substituents were synthe- sized with microwave irradiation in good yields to verify the quantitative analysis data. Friedel-Crafts acylation was carried out by the microwave method for the first time.
基金financial support from the China Natural Science Foundation (No. 201307101)the Science and Technology Department of Sichuan Province (No. 20134FZ0060)+2 种基金Top-notch Young Talents Program of Chinathe Project of Postgraduate Degree ConstructionSouthwest University for Nationalities (No. 2015XWD-S0703)
文摘Graphene sponge(GS) is a porous 3D structure of graphene. Although hydrothermal reduction, chemical vapor deposition, solution reduction and high temperature annealing could be used for the preparation of GS, the size and shape cannot be well controlled. Herein, we reported a facile method to prepare GS under mild condition in a size and shape controllable way. Graphene oxide was lyophilized to form the spongy structure and reduced by steamy hydrazine hydrate to produce GS. The size and shape of GS prepared were nearly identical to that of the container. The reduction degree of GS could be regulated by the reduction temperature and time.
基金Support of our work by National Basic Research Program of China(973 Program,No.2012CB821600)National Natural Science Foundation of China(Nos.21421002,21172241,21302207,21672239)
文摘This review summarizes the recent advances in the catalytic syntheses of CFS-containing organic molecules using various nucleophilic or electrophilic trifluoromethylthiolating reagents.C-halogen and C—H bonds in various molecules have been transformed to C—SCFbonds by transition-metal-catalyzed reactions,such as cross-coupling of aryl halides.Enantioselective reactions controlled by chiral metal complexes or chiral organocatalysts have afforded many trifluoromethylthiolated chiral architectures,such as β-ketoesters and oxindoles.Very recently,visible-light-induced photoredox trifluoromethylthiolations have been developed,providing versatile CFS-containing structures efficiently.
基金National Program for Support of Top-notch Young Professionals,the National Natural Science Foundation of China(Grant No.21307101)the Fundamental Research Funds for the Central Universities,Southwest Minzu University(Grant No.2016NZDFH01).
文摘Graphene/polyester staple sponge(GPSS)is a high-performance adsorbent for the cleanup of crude oil spill,but the use of hydrazine hydrate as the reducing agent for the preparation of GPSS is not friendly to the environment.Herein,we reported that graphene oxide/polyester staple composite could be hydrothermally reduced by bioresource glucose to prepare GPSS of similar performance.GPSS could be applied in the absorption of oils and organic solvents thanks to its large pore volume and hydrophobicity.The absorption capacity of the novel glucose-reduced GPSS was competitive to those of the most effective absorbents for oil spill cleanup.The used GPSS could be easily regenerated by soaking in ethanol to remove the absorbed oil.The green synthesis,high oil absorption performance and easy recycling of the glucose-reduced GPSS make it a good candidate for cleaning oil spills.
基金supported by the Program for New Century Excellent Talents in University (NCET-08-0379) the National Science and Technology Advancement of the Tenth Five-year Plan (2004BA810B05)
文摘An attempt was made to test the validity of the signatures of rare earth elements (REE) as a tool to judge the effect of diagenesis on fossil teeth. Sample REE contents and features of fossil teeth and sediments from Jinsha Relics, Sichuan, Southwest China were analyzed. The difference in REE content between fossil teeth is significantly greater than that between sediments at the Jinsha Relics. Chondrite-normalized REE patterns showed that obvious LREE enrichment and strong Ce and HREE depletion occurred in all fossil teeth samples. Meanwhile δCe and δEu values varied more dramatically in fossil teeth than in sediments. Accordingly, low content, LREE enrichment, strong Ce depletion, the significantly positive correlation between LREE/HREE and δCe, and unchanged (La/Yb)N demonstrated that the fossil teeth from Jinsha Relics have not been contaminated by diagenesis. The REE signature might be a potential proxy to assess the effect of diagenesis on fossil teeth.
文摘Chemical reaction possibility was described quantitatively for the case of nitrotriazolam preparation with 2-clonazepam by using the data of two quantum chemical reactivity indices: net electrophilicity index and Wiberg bond order. Furthennore, relevant reaction mechanism was derived from tlie aspect of quantum chemistry. The results show that the indices used can quantitatively explain the chemical reactivity and reaction mechanism of the nitrotriazolam preparation. To validate the universal applicability of the proposed approach, the authors continued to use the quantum chemical reactivity indices to describe some classic chemical reactions, expecting to predict major issues related to physical organic chemistry, such as new chemical reactions and their mechanisms.
文摘The cytochrome P450 (Cyt-P450) proteins from the fat body and midgut of the cotton bollworm, Helicoverpa armigera, were respectively partially purified by a set of purification procedures including differential centrifugation, solubilization of CHAPS, protein precipitation by PEG precipitation and DE-32 column chromatography. The CytP450 was detected by methods of CO difference spectrum and SDS-PAGE. Fraction of detergent solubilized microsomes from the fat body of H. armigera was purified more than 17-fold. Three protein bands were detected by SDS-PAGE with molecular masses of 70 600, 63 300 and 571 200Da. It is possible that the proteins with molecular mass of 63 300 and 571 200Da were the isozymes of Cyt-P450.
基金Project supported by the National Natural Science Foundation of China (No. 30070200) and the Major Project of Hubei Province Department of Education China (No. 2003A009).
文摘A new thermokinetic reduced extent method for studying of the reversible competitive inhibition of single sub-strate enzyme-catalyzed reactions was proposed in this paper. The reaction that arginase-catalyzed hydrolysis of L-arginine to L-ornithine and urea and the inhibition of this reaction by the product, L-ornithine, and exogenous L-lysine were studied at 37 ℃ in 40 mmolL-1 sodium barbiturate-HCl buffer solution (pH=9.4). Michealis con-stant Km for arginine and maximum velocity Vm of the reaction were determined to be 5.14 mmolL-1 and 1.13× 10-2 mmolL-1s-1, respectively. The product inhibition constant KP and inhibitory constant KI of L-lysine were de-termined to be 1.18 and 5.6 mmolL-1, respectively. All the results have better repeatability and self-consistency and are in agreement with literature values. This new method using more direct thermal information from the proc-ess would give more reliable kinetic information than the traditional initial rate method.
基金financially supported by the National Natural Science Foundation of China(No.21402163)the Science and Technology Department of Sichuan Province(No.2013JY0135)the Graduate Innovation Project of Southwest University for Nationalities(No.CX2015SZ064)
文摘2-Amino-3-nitrile-chromenes with potential antitumor activity were constructed by a novel catalytic system. In combination with a-naphthol, quinine could effectively promote the Michael-cyclization process of malononitrile with functionalized chalcones in high yields and moderate to good enantioselectivity(up to 84% ee). It is notable that the enantioselectivity could be greatly improved when a-naphthol was employed as additive.
基金financially supported by the National Natural Science Foundation of China(No.21402163)the Fundamental Research Funds for the Central Universities of Southwest Minzu University (No. 2016NGJPY02)+1 种基金the Graduate Innovation Project of Southwest Minzu University (No. CX2017SZ016)the Undergraduate Innovation Project of Southwest Minzu University (No. S201610656092)
文摘A novel organocatalytic cascade process initiated by 1,6-conjugated addition has been successfully developed. A range of pharmaceutically active 2-amino-4-aryl-4H-chromenes were readily obtained in high yields(88%-99%) and excellent enantiopurities(86%-99% ee). The functionalized para-Quinone methides(p-OMs) could be facilely obtained.
基金supported by the National Natural Science Foundation of China (21307101, 21301015)the National Basic Research Program of China (2011CB933402)the Science & Technology Department of Sichuan Province (2013FZ0060)
文摘Water pollution has become serious environmental problem nowadays. Advanced oxidation processes(AOP) have been widely applied in water treatment.However, traditional Fenton reaction based on Fe2﹢-H2O2 system has obvious drawbacks, which limit its applications In this study, magnetic Fe3O4core-C shell nanoparticles(Fe3O4@C NPs) were prepared for the decoloration of methylene blue(MB) via the co-precipitation followed by the hydrothermal dehydrogenation of glucose. Fe3O4@C NPs showed high catalytic activity of the decoloration of MB through the decomposition of H2O2 in Fenton-like reactions. Fe3O4@C NPs had much higher activity than bare Fe3O4 cores, suggesting the coating of carbon enhanced the catalytic activity. The performance of Fe3O4@C NPs was better at lower pH and higher temperature, but was significantly inhibited in the presence of radical scavenger tertiary butanol. Fe3O4@C NPs could be magnetic separated and regenerated, and maintained with very good catalytic activity. The implication for the applications of Fe3O4@C NP-catalyzed Fenton-like reactions in water treatment was discussed.
基金supported by the Special Foundation for Basic Scientific Research Operations of Central Universities (2018NQN17)
文摘A desirable near-infrared(NIR)photothermal agent based on Mo-based polyoxometalate cluster with self-adaptive electronic structure for tumor acidity/reducibility-specific therapy was reported in a paper on Journal of the American Chemical Society[1].This‘‘small-big"cluster paradigm displayed the capacity of self-assemble to big molecules under activation both the
基金supported by the National Natural Science Foundation of China(Grant Nos.21307101 and 21301015)the Science & Technology Department of Sichuan Province(Pillar Program)(Grant No.2013FZ0060)+1 种基金Education Department of Sichuan Province(Grant No.15ZA0392)the Project of Postgraduate Degree Construction,Southwest University for Nationalities(Grant No.2015XWD-S0703)
文摘Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modification could be used as Fenton-like catalysts. Surface doping of Ti O2 could concentrate the pollutants surrounding the Fe3O4 catalyst, which might benefit the catalytic performance of Fe3O4. Herein, we reported that Ti O2-doped Fe3O4 nanoparticles(NPs) could be used as high-performance Fenton-like catalyst for dye decoloration in near neutral environment, where the doping of Ti O2 on Fe3O4 surface dramatically improved the catalytic activity of Fe3O4 in Fenton-like reaction. Ti O2-doped Fe3O4 NPs catalyzed the decomposition of H2O2 to oxidize methylene blue without external energy supply, resulting in effective decoloration. Ti O2-doped Fe3O4 NPs showed high catalytic activity under various p H values and even in the presence of radical scavenger. More catalysts and H2O2 would facilitate the decoloration. At higher temperature, the decoloration became faster and more effective. The implication to the environmental applications of Ti O2-doped Fe3O4 NPs is discussed.