Commercially available coal-based activated carbon was treated by nitric acid with different concentrations and the resultant samples were used as catalysts for the direct hydroxylation of benzene to phenol in acetoni...Commercially available coal-based activated carbon was treated by nitric acid with different concentrations and the resultant samples were used as catalysts for the direct hydroxylation of benzene to phenol in acetonitrile. Boehm titration, X-ray photoelectron spectroscopy, scanning electron microscope coupled with an energy dispersive X-ray microanalyzer, and Brunauer-Emmett-Teller method were used to characterize the samples. The number of carboxyl groups on the surface was found to be the main factor affecting the catalytic activity. An optimum catalytic performance with a yield of 15.7% and a selectivity of 87.2% to phenol was obtained.展开更多
Cyanea nozakii Kishinouye （C. nozakii）, a giant cnidarian of the class Scyphomedusae, order Semaeostomeae and family Cyaneidae, is widely distributed in the East China Sea, the Yellow Sea and the Bohai Sea, and is a...Cyanea nozakii Kishinouye （C. nozakii）, a giant cnidarian of the class Scyphomedusae, order Semaeostomeae and family Cyaneidae, is widely distributed in the East China Sea, the Yellow Sea and the Bohai Sea, and is abundant from late summer to early autumn. Venom produced by C. nozakii during mass agglomerations can contaminate seawater resulting in death of the halobios and seriously damage commercial fisheries. Swimmers and fishermen commonly suffer painful stings from this j ellyfish, resulting in local edema, tingling, breathing difficulties, depressed blood pressure and even death. Such effects arise from the complex mixture of biologically active molecules that make up jellyfish venom. In the present study, the hemolytic activity of venom from tentacles of C. nozakii and factors affecting its activity were assayed. The HUso （defined as the amount of protein required to lyse 50% of erythrocytes） of the venom against dove and chicken erythrocytes was 34 and 59 gg/mL, respectively. Carboxylmethyl chitosan and glycerol could increase hemolytic activity at concentrations greater than 0.06% and 0.2 mol/L, respectively.展开更多
To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experimen...To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.展开更多
Polymeric biosurfactants were prepared by the transesterification reaction between vinyl laurate （VILA） and carboxymethylcellulose （CMC）. The reaction was performed in two different reaction media （（A） DMF/pTSA...Polymeric biosurfactants were prepared by the transesterification reaction between vinyl laurate （VILA） and carboxymethylcellulose （CMC）. The reaction was performed in two different reaction media （（A） DMF/pTSA and （B） DMF/K2CO3） at various reaction conditions and using microwave radiation with controlled power as heating source. The obtained water-soluble VILA-CMC derivatives were characterized by FT-IR spectroscopy and their surface-active properties evaluated. All derivatives showed a very low esterification extent and moderate surface tension lowering effect. Nevertheless, they exhibited significant emulsifying efficiency comparable to that of the synthetic surfactant, Tween 20. The results suggested that suitable surface-active VILA-CMC derivatives can be prepared under microwave heating at low microwave power and reaction times in the range of few minutes, which represents a great advantage in comparison to transesterification reactions lasting up to 6 h at conventional heating.展开更多
Three novel transition metal complexes [ML2（phen）]＇H20 （M= Mn, Co, Zn; HL= C10H702NSe, 2-phenyl-4-selenazole carboxylic acid, phen= 1,10-phenanthroline） 1-3 were synthesized and characterized by elemental analysi...Three novel transition metal complexes [ML2（phen）]＇H20 （M= Mn, Co, Zn; HL= C10H702NSe, 2-phenyl-4-selenazole carboxylic acid, phen= 1,10-phenanthroline） 1-3 were synthesized and characterized by elemental analysis, IR spectra. Their crystal structures were deterimined by single-crystal X-ray diffraction method. The antibacterial activities of the complexes against five species of bacteria, Escherichia coli （E. coli）, Staphylococcus epidermidis （S. epidermidis）, Staphylococcus aureus （S. au- reus）, Acinetobacter baumanii （A. baumanii） and Streptococcus viridans （S. viridans）, were tested respectively. The anticancer activities of the complexes against human pancreatic cancer line PANC-28 and human hepatocarcinoma line HuH7 were also studied. The interactions between the complexes and DNA were studied by ethidium bromide （EB） fluorescent probe.展开更多
The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but...The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.展开更多
Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural prope...Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to detail the effect of each functional group, we correlated the activity with the surface density of each group, and found that the carboxyl groups play a pivotal role in two important catalytic reactions, namely the electrochemical oxygen reduction reaction （ORR） and agar conversion to 5-hydroxymethylfurfural （HMF）. During the processes, the hydrophilic surface provides a strong affinity for reaction substrates while the improved porosity allows the efficient diffusion of reactants and products. Furthermore, the activity of functionalized CNTs for agar conversion remained almost unchanged during nine cycles of reaction. This work highlights a strategy for improving the activity of CNTs for electrochemical ORR and agar conversion reactions, as well a promising application of carboxyl-rich CNTs as a solid acid catalyst to produce high-purity HMF--an important chemical intermediate.展开更多
基金This work was supported by the National Natural Science Foundation of China （No.20502017, No.20872102, and No.21021001）, the Program for Changjiang Scholars and Innovative Research Team in University （No.IRT0846）, and the characterization of the catalyst from Analytic and Testing Center of Sichuan University are greatly appreciated.
文摘Commercially available coal-based activated carbon was treated by nitric acid with different concentrations and the resultant samples were used as catalysts for the direct hydroxylation of benzene to phenol in acetonitrile. Boehm titration, X-ray photoelectron spectroscopy, scanning electron microscope coupled with an energy dispersive X-ray microanalyzer, and Brunauer-Emmett-Teller method were used to characterize the samples. The number of carboxyl groups on the surface was found to be the main factor affecting the catalytic activity. An optimum catalytic performance with a yield of 15.7% and a selectivity of 87.2% to phenol was obtained.
基金Supported by the National Natural Science Foundation of China(Nos.41376004,41406152)the Key R&D program of Shandong Province(Nos.2015GSF115022,2015GSF115034)the China Postdoctoral Science Foundation(No.2013M531654)
文摘Cyanea nozakii Kishinouye （C. nozakii）, a giant cnidarian of the class Scyphomedusae, order Semaeostomeae and family Cyaneidae, is widely distributed in the East China Sea, the Yellow Sea and the Bohai Sea, and is abundant from late summer to early autumn. Venom produced by C. nozakii during mass agglomerations can contaminate seawater resulting in death of the halobios and seriously damage commercial fisheries. Swimmers and fishermen commonly suffer painful stings from this j ellyfish, resulting in local edema, tingling, breathing difficulties, depressed blood pressure and even death. Such effects arise from the complex mixture of biologically active molecules that make up jellyfish venom. In the present study, the hemolytic activity of venom from tentacles of C. nozakii and factors affecting its activity were assayed. The HUso （defined as the amount of protein required to lyse 50% of erythrocytes） of the venom against dove and chicken erythrocytes was 34 and 59 gg/mL, respectively. Carboxylmethyl chitosan and glycerol could increase hemolytic activity at concentrations greater than 0.06% and 0.2 mol/L, respectively.
基金financially supported by the National Natural Science Foundation of China (No.51504084)the Education Department of Fujian Province (No.JA15493)
文摘To research techniques for removing the water blocking effect caused by hydraulic applications in coal seams,the use of surfactants is proposed,based on the mechanics of the water blocking effect.Centrifugal experiments were used to validate the effects of using surfactants;the results show that after dealing with vacuum saturation with water,the volume of micropores decreases,which results in a larger average pore size,and the volume of transitional pores,mesopores,macropores and total pores increases.Based on the distribution of pore size,the operation mode of ‘‘water infusion after gas extraction,then continuing gas extraction" is recommended to improve the volume of coal mine gas drainage.When the reflectance of vitrinite in coal samples is less than 1,using the surfactants Fast T,1631,APG,BS can mitigate the damage caused by the water blocking effect.But when the reflectance of vitrinite is larger than 1.4,the damage caused by the water blocking effect can be increased.When the surfactant CMC is used in hydraulic applications,the capillary forces of coal samples are almost negative,which means the capillary force is in the same direction as the gas extraction.The direction of capillary forces benefits the gas flow.So,using CMC can play an active role in removing the water blocking effect.Centrifugal experiments confirm that using CMC can effectively remove the water blocking effect,which has a beneficial effect on improving the gas drainage volume.
文摘Polymeric biosurfactants were prepared by the transesterification reaction between vinyl laurate （VILA） and carboxymethylcellulose （CMC）. The reaction was performed in two different reaction media （（A） DMF/pTSA and （B） DMF/K2CO3） at various reaction conditions and using microwave radiation with controlled power as heating source. The obtained water-soluble VILA-CMC derivatives were characterized by FT-IR spectroscopy and their surface-active properties evaluated. All derivatives showed a very low esterification extent and moderate surface tension lowering effect. Nevertheless, they exhibited significant emulsifying efficiency comparable to that of the synthetic surfactant, Tween 20. The results suggested that suitable surface-active VILA-CMC derivatives can be prepared under microwave heating at low microwave power and reaction times in the range of few minutes, which represents a great advantage in comparison to transesterification reactions lasting up to 6 h at conventional heating.
基金financially supported by Natural Science Foundation of Zhejiang Province (Y4080256)
文摘Three novel transition metal complexes [ML2（phen）]＇H20 （M= Mn, Co, Zn; HL= C10H702NSe, 2-phenyl-4-selenazole carboxylic acid, phen= 1,10-phenanthroline） 1-3 were synthesized and characterized by elemental analysis, IR spectra. Their crystal structures were deterimined by single-crystal X-ray diffraction method. The antibacterial activities of the complexes against five species of bacteria, Escherichia coli （E. coli）, Staphylococcus epidermidis （S. epidermidis）, Staphylococcus aureus （S. au- reus）, Acinetobacter baumanii （A. baumanii） and Streptococcus viridans （S. viridans）, were tested respectively. The anticancer activities of the complexes against human pancreatic cancer line PANC-28 and human hepatocarcinoma line HuH7 were also studied. The interactions between the complexes and DNA were studied by ethidium bromide （EB） fluorescent probe.
基金supported by grants from the National Natural Science Foundation of China (No.81571987 and 81371820)the Ph.D. Candidate Research Innovation Fund of Nankai University (2015) (No.68150003)
文摘The multifunctional trans-activator Tat is an essential regulatory protein for HIV-1 replication and is characterized by high sequence diversity. Numerous experimental studies have examined Tat in HIV-1 subtype B, but research on subtype C Tat is lacking, despite the high prevalence of infections caused by subtype C worldwide. We hypothesized that amino acid differences contribute to functional differences among Tat proteins. In the present study, we found that subtype B NL4-3Tat and subtype C isolate HIV1084 i Tat exhibited differences in stability by overexpressing the fusion protein Tat-Flag. In addition, 1084 i Tat can activate LTR and NF-κB more efficiently than NL4-3 Tat. In analyses of the activities of the truncated forms of Tat, we found that the carboxylterminal region of Tat regulates its stability and transactivity. According to our results, we speculated that the differences in stability between B-Tat and C-Tat result in differences in transactivation ability.
文摘Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to detail the effect of each functional group, we correlated the activity with the surface density of each group, and found that the carboxyl groups play a pivotal role in two important catalytic reactions, namely the electrochemical oxygen reduction reaction （ORR） and agar conversion to 5-hydroxymethylfurfural （HMF）. During the processes, the hydrophilic surface provides a strong affinity for reaction substrates while the improved porosity allows the efficient diffusion of reactants and products. Furthermore, the activity of functionalized CNTs for agar conversion remained almost unchanged during nine cycles of reaction. This work highlights a strategy for improving the activity of CNTs for electrochemical ORR and agar conversion reactions, as well a promising application of carboxyl-rich CNTs as a solid acid catalyst to produce high-purity HMF--an important chemical intermediate.
