A rapid, sensitive and reproducible high performance liquid chromatography （HPLC） method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular- weight sulfated poly...A rapid, sensitive and reproducible high performance liquid chromatography （HPLC） method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular- weight sulfated polysaccharide （GFS） in vivo. The metabolism of GFS has been shown to fit a two component model following its administration by intravenous injection, and its pharmacokinetic parameters were determined to be as follows： half-time of distribution phase （t1/2α）=11.2±2.93 min, half-time of elimination phase （tl/2α）=98.20±25.78 min, maximum concentration （Cmax）=110.53 gg/mL and peak time （Tmax）=5 min. The pharmacokinetic behavior of GFS was also investigated following intragastric administration. However, the concentration of GFS found in serum was too low for detection, and GFS could only be detected for up to 2 h after intragastric administration （200 mg/kg body weight）. Thus, the bioavailability of GFS was low following intragastric administration because of the metabolism of GFS. In conclusion, HPLC with post-column derivatization could be used for quantitative microanalysis and pharmacokinetic studies to determine the presence of polysaccharides in the serum following intravenous injection.展开更多
A series of polyvinylpyrrolidone-stabilized heteropolyacids(PVP-HPAs)are generated by self-assembly of HPAs and PVP in methanol.The PVP-HPAs are then employed as catalysts for the synthesis of poly(oxymethylene)dimeth...A series of polyvinylpyrrolidone-stabilized heteropolyacids(PVP-HPAs)are generated by self-assembly of HPAs and PVP in methanol.The PVP-HPAs are then employed as catalysts for the synthesis of poly(oxymethylene)dimethyl ethers(DMMn,n1)by the methanolysis of trioxane.The results suggest that the acidity of PVP-HPAs is tunable by changing the ratio of PVP and HPAs,which is a key factor for the selectivity of the DMMn product.By optimizing the composition and reaction conditions,two types of PVP-HPA,PVP-phosphotungstic acid(PVP-HPW)in a PVP/HPW ratio of 1/4:1 and PVP-silicotungstic acid(PVP-HSi W)in a PVP/HSi W ratio of 1/4:3/4,respectively afford 52.4%and 50.3%yields of DMM2–5.The optimized catalysts are reusable for a minimum of 10 times without a significant drop in performance.展开更多
Polyoxometalates （POMs）, with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. In a new direction, POMs having a ...Polyoxometalates （POMs）, with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. In a new direction, POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation. This review focuses on very recent developments of POM-based catalysts for water oxidation to O2. In the very extensive family of POMs, tetra-core sandwich-type Ru- and Co-containing POM complexes, namely [Ru404（OH）2（H20）4（y-SiW10O36）2]10- and [CO4（H2O）2（a-PWgO34）2]10- exhibit the ability to facilitate water oxidation under electrocatalytic and/or photocatalytic conditions. However, it is concluded that much work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems. In addition, recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted.展开更多
High performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry(HPLC-Q-TOF-MS)method was developed for analyzing the hydrolytic mixtures of ginsenoside R_(g1) in acidic conditions(pH 3)....High performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry(HPLC-Q-TOF-MS)method was developed for analyzing the hydrolytic mixtures of ginsenoside R_(g1) in acidic conditions(pH 3). Three catalysts, a heteropolyacid(H_4SiW_(12)O_(40), SiW_(12) for short), its complex with γ-CD(SiW_(12)/γ-CD for short) and formic acid, were used for comparison. The chemical transformation products were identified based on the accurate mass measurement and the fragment ions obtained from tandem mass spectrometry. It was concluded that the catalytic efficiency of SiW_(12)(≈SiW_(12)/γ-CD) is ca. 410 times higher than that of formic acid, thus becoming the most efficient catalyst for chemical transformations of ginsenosides.展开更多
The non-radiative recombination loss caused by diverse defects within SnO_(2)electron transport layer(ETL),perovskite film,and their interface greatly hinders the further improvement of the performance and stability o...The non-radiative recombination loss caused by diverse defects within SnO_(2)electron transport layer(ETL),perovskite film,and their interface greatly hinders the further improvement of the performance and stability of flexible perovskite solar cells(PSCs).Therefore,it is urgent to develop an effective strategy to address these issues.Herein,a multifunctional material,phospho-ethanolamine(PE),is introduced into SnO_(2)aqueous colloids to suppress defects and prepare high-quality ETL.The results demonstrate that the incorporation of PE can significantly reduce the number of Sn dangling bonds due to the formation of new Sn–O–P bonds,which is beneficial to ameliorating the electrical properties of SnO_(2)and obtaining dense SnO_(2)film.Meanwhile,the amino group(NH_(2))of PE can interact with uncoordinated Pb^(2+)in perovskite,thereby suppressing SnO_(2)/perovskite interface defects and obtaining improved perovskite film quality.Consequently,the optimized flexible and rigid PSCs based on the SnO_(2)-PE composite ETL yield outstanding photoelectric conversion efficiency(PCE)of 18.48%and 21.61%,respectively.Moreover,flexible PSCs based on SnO_(2)-PE present excellent mechanical durability,and 90.6%of the original PCE is retained after 1000 bending cycles.展开更多
基金Supported by the National Natural Science Foundation of China(No.41376166)the Ocean Public Welfare Scientific Research Project(Nos.201005024,201405040)+1 种基金the Jiangsu Science and Technology Project(No.BE2012687)the Special Fund for Cooperation between Jilin Province and Chinese Academy of Sciences(No.2013SYHZ0023)
文摘A rapid, sensitive and reproducible high performance liquid chromatography （HPLC） method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular- weight sulfated polysaccharide （GFS） in vivo. The metabolism of GFS has been shown to fit a two component model following its administration by intravenous injection, and its pharmacokinetic parameters were determined to be as follows： half-time of distribution phase （t1/2α）=11.2±2.93 min, half-time of elimination phase （tl/2α）=98.20±25.78 min, maximum concentration （Cmax）=110.53 gg/mL and peak time （Tmax）=5 min. The pharmacokinetic behavior of GFS was also investigated following intragastric administration. However, the concentration of GFS found in serum was too low for detection, and GFS could only be detected for up to 2 h after intragastric administration （200 mg/kg body weight）. Thus, the bioavailability of GFS was low following intragastric administration because of the metabolism of GFS. In conclusion, HPLC with post-column derivatization could be used for quantitative microanalysis and pharmacokinetic studies to determine the presence of polysaccharides in the serum following intravenous injection.
基金financially supported by the National Basic Research Program of China(2011CBA00508)the National Natural Science Foundation of China(21173175,21303141)+1 种基金the Research Fund for the Doctoral Program of Higher Education(20110121130002)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1036)
文摘A series of polyvinylpyrrolidone-stabilized heteropolyacids(PVP-HPAs)are generated by self-assembly of HPAs and PVP in methanol.The PVP-HPAs are then employed as catalysts for the synthesis of poly(oxymethylene)dimethyl ethers(DMMn,n1)by the methanolysis of trioxane.The results suggest that the acidity of PVP-HPAs is tunable by changing the ratio of PVP and HPAs,which is a key factor for the selectivity of the DMMn product.By optimizing the composition and reaction conditions,two types of PVP-HPA,PVP-phosphotungstic acid(PVP-HPW)in a PVP/HPW ratio of 1/4:1 and PVP-silicotungstic acid(PVP-HSi W)in a PVP/HSi W ratio of 1/4:3/4,respectively afford 52.4%and 50.3%yields of DMM2–5.The optimized catalysts are reusable for a minimum of 10 times without a significant drop in performance.
基金financed by the Australian Research Council Discovery Scheme and UNSW Science Faculty Research Grants Program
文摘Polyoxometalates （POMs）, with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. In a new direction, POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation. This review focuses on very recent developments of POM-based catalysts for water oxidation to O2. In the very extensive family of POMs, tetra-core sandwich-type Ru- and Co-containing POM complexes, namely [Ru404（OH）2（H20）4（y-SiW10O36）2]10- and [CO4（H2O）2（a-PWgO34）2]10- exhibit the ability to facilitate water oxidation under electrocatalytic and/or photocatalytic conditions. However, it is concluded that much work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems. In addition, recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted.
基金supported by the National Natural Science Foundation of China(21371025),the 111 Project(B07012)the degree and postgraduate education development research project(YJYJG2015B07)by Beijing Institute of Technology
文摘High performance liquid chromatography coupled with quadruple-time-of-flight mass spectrometry(HPLC-Q-TOF-MS)method was developed for analyzing the hydrolytic mixtures of ginsenoside R_(g1) in acidic conditions(pH 3). Three catalysts, a heteropolyacid(H_4SiW_(12)O_(40), SiW_(12) for short), its complex with γ-CD(SiW_(12)/γ-CD for short) and formic acid, were used for comparison. The chemical transformation products were identified based on the accurate mass measurement and the fragment ions obtained from tandem mass spectrometry. It was concluded that the catalytic efficiency of SiW_(12)(≈SiW_(12)/γ-CD) is ca. 410 times higher than that of formic acid, thus becoming the most efficient catalyst for chemical transformations of ginsenosides.
基金the National Key Research and Development Program of China(2020YFA0715000).
文摘The non-radiative recombination loss caused by diverse defects within SnO_(2)electron transport layer(ETL),perovskite film,and their interface greatly hinders the further improvement of the performance and stability of flexible perovskite solar cells(PSCs).Therefore,it is urgent to develop an effective strategy to address these issues.Herein,a multifunctional material,phospho-ethanolamine(PE),is introduced into SnO_(2)aqueous colloids to suppress defects and prepare high-quality ETL.The results demonstrate that the incorporation of PE can significantly reduce the number of Sn dangling bonds due to the formation of new Sn–O–P bonds,which is beneficial to ameliorating the electrical properties of SnO_(2)and obtaining dense SnO_(2)film.Meanwhile,the amino group(NH_(2))of PE can interact with uncoordinated Pb^(2+)in perovskite,thereby suppressing SnO_(2)/perovskite interface defects and obtaining improved perovskite film quality.Consequently,the optimized flexible and rigid PSCs based on the SnO_(2)-PE composite ETL yield outstanding photoelectric conversion efficiency(PCE)of 18.48%and 21.61%,respectively.Moreover,flexible PSCs based on SnO_(2)-PE present excellent mechanical durability,and 90.6%of the original PCE is retained after 1000 bending cycles.
