Polymer-stabilized platinum/ruthenium bimetallic colloids （Pt/Ru） were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow s...Polymer-stabilized platinum/ruthenium bimetallic colloids （Pt/Ru） were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow size distributions. Catalytic performance of the Pt/Ru colloidal catalysts was investigated on the selective hydrogenation of crontonaldehyde （CRAL）. A suitable amount of the added metal ions and base can improve the selectivity of CRAL to crotylalcohol （CROL） remarkably. The catalytic activity and the selectivity are dependent on the compositions of bimetallic colloids. Thereinto, PVP-stabilized 9Pt/1Ru colloid with a molar ratio of metals Pt：Ru = 9：1 shows the highest catalytic selectivity 77.3% to CROL at 333 K under 4.0 MPa of hydrogen.展开更多
The critical node(CN) is an important stage during seed aging, which is related to effective genebank conservation. Previous studies have demonstrated that proteins undergo carbonylated modification at the CN in rice,...The critical node(CN) is an important stage during seed aging, which is related to effective genebank conservation. Previous studies have demonstrated that proteins undergo carbonylated modification at the CN in rice, indicating oxidative damage. However, the levels of reactive carbonyl species(RCS) and the associated scavenging system at the CN are largely unknown. In this study, we optimized methods for the extraction and analysis of RCS from dry rice embryos. In order to acquire seeds at the CN, rice seeds were subjected to natural conditions for 7, 9, 11 and 13 months, and the seed germination rates were reduced to 90%, 82%, 71% and 57%, respectively. We chose the stage with seed germination rate of 82% as the CN according to the rice seed vigor loss curve. The levels of crotonaldehyde and 4-hydroxy-(E)-2-nonenal(HNE) were significantly increased at the CN. In addition, genes encoding carbonyl-scavenging enzyme, including Os ALDHs and Os AKRs, were significantly down-regulated at the CN, and reductions in the expression of Os ALDH2-2, Os ALDH2-5, Os ALDH3-4, Os ALDH7, Os AKR1 and Os AKR2 in particular could be responsible for RCS accumulation. Thus, the accumulations of crotonaldehyde and HNE and down-regulation of genes encoding carbonyl-scavenging enzyme might be related to an accelerating loss of seed viability at the CN.展开更多
A new copolymer has been synthesized by the copolymerization of acrylic acid with crotonaldehyde in water using K 2S 2O 8 as initiator.The copolymer was characterized by DSC,IR and 13C-NMR.The effects of pH on the rat...A new copolymer has been synthesized by the copolymerization of acrylic acid with crotonaldehyde in water using K 2S 2O 8 as initiator.The copolymer was characterized by DSC,IR and 13C-NMR.The effects of pH on the rate and conversion of copolymerization and copolymer’s composition have been investigated.The results show that,as pH increases,the rate and conversion decrease,especially at pH 5～7,while the content of crotonaldehyde in copolymer increases.It has been proved by IR that there is hydrogen bond between acrylic acid and crotonaldehyde at low pH.The study indicates that hydrogen bond improves the ability of polymerization.However,at high pH,acrylic acid was found as electron acceptor; crotonaldehyde as electron donor.A model of “charge transfer polymerization” was employed to illustrate the copolymerization at high pH.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.29774037,29873058)the Chinese Academy of Sciences(No.KJ952-J1-508)is gratefully acknowledged.
文摘Polymer-stabilized platinum/ruthenium bimetallic colloids （Pt/Ru） were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow size distributions. Catalytic performance of the Pt/Ru colloidal catalysts was investigated on the selective hydrogenation of crontonaldehyde （CRAL）. A suitable amount of the added metal ions and base can improve the selectivity of CRAL to crotylalcohol （CROL） remarkably. The catalytic activity and the selectivity are dependent on the compositions of bimetallic colloids. Thereinto, PVP-stabilized 9Pt/1Ru colloid with a molar ratio of metals Pt：Ru = 9：1 shows the highest catalytic selectivity 77.3% to CROL at 333 K under 4.0 MPa of hydrogen.
基金supported by the National Key Technology R&D Program, China (Grant No. 2013BAD01B01)the National Natural Science Foundation of China Program (Grant Nos. 31371713 and 31401470)+1 种基金the Agricultural Science and Technology Innovation Program / Crop Germplasm Resources Preservation and Sharing Innovation Teamsupported by Central Laboratory of Biotechnology Research Institute, Chinese Academy of Agricultural Science
文摘The critical node(CN) is an important stage during seed aging, which is related to effective genebank conservation. Previous studies have demonstrated that proteins undergo carbonylated modification at the CN in rice, indicating oxidative damage. However, the levels of reactive carbonyl species(RCS) and the associated scavenging system at the CN are largely unknown. In this study, we optimized methods for the extraction and analysis of RCS from dry rice embryos. In order to acquire seeds at the CN, rice seeds were subjected to natural conditions for 7, 9, 11 and 13 months, and the seed germination rates were reduced to 90%, 82%, 71% and 57%, respectively. We chose the stage with seed germination rate of 82% as the CN according to the rice seed vigor loss curve. The levels of crotonaldehyde and 4-hydroxy-(E)-2-nonenal(HNE) were significantly increased at the CN. In addition, genes encoding carbonyl-scavenging enzyme, including Os ALDHs and Os AKRs, were significantly down-regulated at the CN, and reductions in the expression of Os ALDH2-2, Os ALDH2-5, Os ALDH3-4, Os ALDH7, Os AKR1 and Os AKR2 in particular could be responsible for RCS accumulation. Thus, the accumulations of crotonaldehyde and HNE and down-regulation of genes encoding carbonyl-scavenging enzyme might be related to an accelerating loss of seed viability at the CN.
文摘A new copolymer has been synthesized by the copolymerization of acrylic acid with crotonaldehyde in water using K 2S 2O 8 as initiator.The copolymer was characterized by DSC,IR and 13C-NMR.The effects of pH on the rate and conversion of copolymerization and copolymer’s composition have been investigated.The results show that,as pH increases,the rate and conversion decrease,especially at pH 5～7,while the content of crotonaldehyde in copolymer increases.It has been proved by IR that there is hydrogen bond between acrylic acid and crotonaldehyde at low pH.The study indicates that hydrogen bond improves the ability of polymerization.However,at high pH,acrylic acid was found as electron acceptor; crotonaldehyde as electron donor.A model of “charge transfer polymerization” was employed to illustrate the copolymerization at high pH.
