Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further t...Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further to synthesize heterogeneous catalyst with highly dispersed RuNi nanoparticles (Ru1Ni1.5@UiO-66(Ce)-12 h). The construction of Ce-O-Ru/Ni heterogeneous interfaces and Ni–Ru bonds provide electron transfer channels from Ce-oxo clusters and Ni species to Ru species. Furthermore, the microenvironment and electronic structure of Ru0 active sites were synergistically regulated by adjusting the content of metal-organic frameworks (MOFs) defects and Ni promoter, thereby enhancing the adsorption and activation ability of H–H and C=C bonds. Therefore, Ru1Ni1.5@UiO-66(Ce)-12 h achieved dicyclopentadiene saturated hydrogenation (100% conversion) to tetrahydrodicyclopentadiene (∼ 100% selectivity) under mild condition (35℃, 1 MPa) with only 25 min. Meanwhile, the sample exhibited excellent structural stability after 6 cycles test. This study provides a promising strategy for the rational design of remarkable noble metal-based catalysts for practical applications.展开更多
The Eleventh Five-Year Plan places emphasis on enhancing the nation's innovation capabilities. Innovation forms a key part of the strategy to change China's central mode of growth to one that is based on s... The Eleventh Five-Year Plan places emphasis on enhancing the nation's innovation capabilities. Innovation forms a key part of the strategy to change China's central mode of growth to one that is based on science and technology.……展开更多
On September 20,the Network+ rural innovation summit that highlights the number of Jingdong online stores surpassing 1,000 was held in Zunyi County.At the summit Jingdong Group and Guizhou Provincial Commercial Depart...On September 20,the Network+ rural innovation summit that highlights the number of Jingdong online stores surpassing 1,000 was held in Zunyi County.At the summit Jingdong Group and Guizhou Provincial Commercial Department signed a joint strategic contract to promote rural e-commerce.Both sides will make best use of '3F strategy' of Jindong rural e-commerce and the advantages of Guizhou Province,to launch a batch of rural e-commerce projects of the people and for the people,to help local rural residents gain wealth and promote the restructuring of the rural economy.展开更多
The p27Kip1 is a cell cycle repressor protein that regulates primarily the cell cycle transition from G1 to S phase and hence the DNA replication is in the S phase and cell division in the M phase. Expression of p27Ki...The p27Kip1 is a cell cycle repressor protein that regulates primarily the cell cycle transition from G1 to S phase and hence the DNA replication is in the S phase and cell division in the M phase. Expression of p27Kip1 protein has dual roles for both cancer prevention and promotion. For example, numerous nutritional and chemopreventive anti-cancer agents specifically increase the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. On the other hand, pro-cancer agents (like glucose, insulin and other growth factors frequently seen in obesity and/or diabetes) specifically decrease the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. Unlike expression of any other cell cycle regulatory proteins, expression of p27Kip1 protein is very unusual. The mRNA of p27Kip1 has a very long and unusual 5’-untranslated region (from -575 to -1 in human). It appears that the 5’-untranslated region of p27Kip1 mRNA forms two alternative secondary structures. One increases the expression of p27Kip1 protein when anti-cancer agents are added and another decrease the expression of p27K1p1 when pro-cancer agents are added. For this short concept proposal, Dr. Albert Einstein’s “visualized thought experiments (German: Gedanken experiment)” were used as a fundamental tool for understanding how either anti- or pro-cancer agents bring the primary structure of the 5’-untranslated region of p27Kip1 mRNA into two alternative secondary structures, thereby either increasing or decreasing, respectively, the translation initiation of p27Kip1 protein.展开更多
Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for...Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for the methane reaction)dramatically transformed to promotion(for the ethane,propane,and n-hexane reactions)as the carbon chain length increased,whereas the remarkable promotion of Nb_(2)O_(5)gradually weakened with an increase in the carbon chain length.Based on a detailed study of the oxidation reactions of methane and propane over the catalysts,the different roles of the promoters in the reactions were ascribed to differences in the acidic properties of the surface and the oxidation or reduction states of the Pt species.The MoO_(3)promoter could decorate the surface of the Pt species for a Pt-Mo/ZrO_(2)catalyst,whereas the Nb_(2)O_(5)promoter on the support could be partially covered by Pt particles for a Pt-Nb/ZrO_(2)catalyst.The formation of accessible Pt-MoO_(3)interfacial sites,a high concentration of metallic Pt species,and a high surface acidity in Pt-Mo/ZrO_(2)were responsible for the enhanced activity for catalytic propane combustion.The lack of enough accessible Pt-Nb_(2)O_(5)interfacial sites but an enhanced surface acid sites in Pt-Nb/ZrO_(2)explained the slight improvement in activity for catalytic propane combustion.However,the stabilized Pt^(n+)species in Pt-Nb/ZrO_(2)were responsible for the much-improved activity for methane combustion,whereas the Pt^(n+)species in Pt-Mo/ZrO_(2)could be reduced during the oxidation reaction,and the fewer exposed surface Pt species because of MoO_(3)decoration accounted for the inhibited activity for methane combustion.In addition,it can be concluded that MoO_(3)promotion is favorable for the activation of C-C bonds,whereas Nb_(2)O_(5)promotion is more beneficial for the activation of C-H bonds with high energy.展开更多
Objective To investigate the junction of Sp1 consensus sites to human telomerase reverse tran-scriptase (hTERT) promoter in different cell lines and in TRA-treated Hela cell. Methods Different length ofhTERT promoter ...Objective To investigate the junction of Sp1 consensus sites to human telomerase reverse tran-scriptase (hTERT) promoter in different cell lines and in TRA-treated Hela cell. Methods Different length ofhTERT promoter was cloned and inserted into pGL3/basic reporter plasmid. The last four Sp1 sites were deleted byPCR and pGL3B/TRTP413Δ reporter plasmid was constructed. All reporter plasmids were transiently transfected in-to 293, A549, Hela and HepG2 cell lines. 48 h after transfection, luciferase activity was analyzed. hTERT promoteractivity of Hela cell which was treated with trans-retinoid acid (TRA) was tested too. Total RNA of these cells wereextracted and reverse transcript. hTERT mRNA level was analyzed in all tested cells. c-Myc and Sp1 expression wereexamined in Hela cell before and after TRA treatment. U937 was used as a positive control in TRA treatment.Results hTERT was expressed at different level in all tested cell lines. 207bp promoter upstream of transcriptionstart site maintained complete activity. Deletion of last 4 Sp1l sites greatly decreased activity of hTERT promoter, andalmost eliminated its activity in HepG2. TRA increased the activity of different length hTERT promoters in Hela cell,but the activity of Sp1 site-deleted promoter decreased by 3 times. Unlike U937 cell, hTERT expression of Hela cellincreased after TRA treatment, and c-Myc and Sp1 mRNA level were relatively stable. Conclusion Sp1 site wasrequired for transactivation of hTERT promoter and played an important role during TRA treatment.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFB3500700)the National Natural Science Foundation of China(No.51972024)the Natural Science Foundation of Guangdong Province(No.2022A1515010185).
文摘Olefin hydrogenation under mild condition is crucial and challenging for industrial applications. Herein, defective UiO-66(Ce) was constructed by using cyanuric acid as the molecular etching “scissors” and further to synthesize heterogeneous catalyst with highly dispersed RuNi nanoparticles (Ru1Ni1.5@UiO-66(Ce)-12 h). The construction of Ce-O-Ru/Ni heterogeneous interfaces and Ni–Ru bonds provide electron transfer channels from Ce-oxo clusters and Ni species to Ru species. Furthermore, the microenvironment and electronic structure of Ru0 active sites were synergistically regulated by adjusting the content of metal-organic frameworks (MOFs) defects and Ni promoter, thereby enhancing the adsorption and activation ability of H–H and C=C bonds. Therefore, Ru1Ni1.5@UiO-66(Ce)-12 h achieved dicyclopentadiene saturated hydrogenation (100% conversion) to tetrahydrodicyclopentadiene (∼ 100% selectivity) under mild condition (35℃, 1 MPa) with only 25 min. Meanwhile, the sample exhibited excellent structural stability after 6 cycles test. This study provides a promising strategy for the rational design of remarkable noble metal-based catalysts for practical applications.
文摘 The Eleventh Five-Year Plan places emphasis on enhancing the nation's innovation capabilities. Innovation forms a key part of the strategy to change China's central mode of growth to one that is based on science and technology.……
文摘On September 20,the Network+ rural innovation summit that highlights the number of Jingdong online stores surpassing 1,000 was held in Zunyi County.At the summit Jingdong Group and Guizhou Provincial Commercial Department signed a joint strategic contract to promote rural e-commerce.Both sides will make best use of '3F strategy' of Jindong rural e-commerce and the advantages of Guizhou Province,to launch a batch of rural e-commerce projects of the people and for the people,to help local rural residents gain wealth and promote the restructuring of the rural economy.
文摘The p27Kip1 is a cell cycle repressor protein that regulates primarily the cell cycle transition from G1 to S phase and hence the DNA replication is in the S phase and cell division in the M phase. Expression of p27Kip1 protein has dual roles for both cancer prevention and promotion. For example, numerous nutritional and chemopreventive anti-cancer agents specifically increase the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. On the other hand, pro-cancer agents (like glucose, insulin and other growth factors frequently seen in obesity and/or diabetes) specifically decrease the expression of p27Kip1 protein without directly affecting the expression of any other cell cycle regulatory proteins. Unlike expression of any other cell cycle regulatory proteins, expression of p27Kip1 protein is very unusual. The mRNA of p27Kip1 has a very long and unusual 5’-untranslated region (from -575 to -1 in human). It appears that the 5’-untranslated region of p27Kip1 mRNA forms two alternative secondary structures. One increases the expression of p27Kip1 protein when anti-cancer agents are added and another decrease the expression of p27K1p1 when pro-cancer agents are added. For this short concept proposal, Dr. Albert Einstein’s “visualized thought experiments (German: Gedanken experiment)” were used as a fundamental tool for understanding how either anti- or pro-cancer agents bring the primary structure of the 5’-untranslated region of p27Kip1 mRNA into two alternative secondary structures, thereby either increasing or decreasing, respectively, the translation initiation of p27Kip1 protein.
文摘Pt/ZrO_(2)catalysts promoted with MoO_(3)and Nb_(2)O_(5)were tested for the combustion of short-chain alkanes(namely,methane,ethane,propane,and n-hexane).For short-chain alkane combustion,the inhibition of MoO_(3)(for the methane reaction)dramatically transformed to promotion(for the ethane,propane,and n-hexane reactions)as the carbon chain length increased,whereas the remarkable promotion of Nb_(2)O_(5)gradually weakened with an increase in the carbon chain length.Based on a detailed study of the oxidation reactions of methane and propane over the catalysts,the different roles of the promoters in the reactions were ascribed to differences in the acidic properties of the surface and the oxidation or reduction states of the Pt species.The MoO_(3)promoter could decorate the surface of the Pt species for a Pt-Mo/ZrO_(2)catalyst,whereas the Nb_(2)O_(5)promoter on the support could be partially covered by Pt particles for a Pt-Nb/ZrO_(2)catalyst.The formation of accessible Pt-MoO_(3)interfacial sites,a high concentration of metallic Pt species,and a high surface acidity in Pt-Mo/ZrO_(2)were responsible for the enhanced activity for catalytic propane combustion.The lack of enough accessible Pt-Nb_(2)O_(5)interfacial sites but an enhanced surface acid sites in Pt-Nb/ZrO_(2)explained the slight improvement in activity for catalytic propane combustion.However,the stabilized Pt^(n+)species in Pt-Nb/ZrO_(2)were responsible for the much-improved activity for methane combustion,whereas the Pt^(n+)species in Pt-Mo/ZrO_(2)could be reduced during the oxidation reaction,and the fewer exposed surface Pt species because of MoO_(3)decoration accounted for the inhibited activity for methane combustion.In addition,it can be concluded that MoO_(3)promotion is favorable for the activation of C-C bonds,whereas Nb_(2)O_(5)promotion is more beneficial for the activation of C-H bonds with high energy.
基金Supported by Shanghai Science and Technology Development Foundation (01JC14025) and the 4th phase financial support of Shanghai EducationCommittee.
文摘Objective To investigate the junction of Sp1 consensus sites to human telomerase reverse tran-scriptase (hTERT) promoter in different cell lines and in TRA-treated Hela cell. Methods Different length ofhTERT promoter was cloned and inserted into pGL3/basic reporter plasmid. The last four Sp1 sites were deleted byPCR and pGL3B/TRTP413Δ reporter plasmid was constructed. All reporter plasmids were transiently transfected in-to 293, A549, Hela and HepG2 cell lines. 48 h after transfection, luciferase activity was analyzed. hTERT promoteractivity of Hela cell which was treated with trans-retinoid acid (TRA) was tested too. Total RNA of these cells wereextracted and reverse transcript. hTERT mRNA level was analyzed in all tested cells. c-Myc and Sp1 expression wereexamined in Hela cell before and after TRA treatment. U937 was used as a positive control in TRA treatment.Results hTERT was expressed at different level in all tested cell lines. 207bp promoter upstream of transcriptionstart site maintained complete activity. Deletion of last 4 Sp1l sites greatly decreased activity of hTERT promoter, andalmost eliminated its activity in HepG2. TRA increased the activity of different length hTERT promoters in Hela cell,but the activity of Sp1 site-deleted promoter decreased by 3 times. Unlike U937 cell, hTERT expression of Hela cellincreased after TRA treatment, and c-Myc and Sp1 mRNA level were relatively stable. Conclusion Sp1 site wasrequired for transactivation of hTERT promoter and played an important role during TRA treatment.
