As a green and sustainable technology,heterogeneous photocatalysis using semiconductors has received much attention during the past decades because of its potential to address energy and environmental problems. Among ...As a green and sustainable technology,heterogeneous photocatalysis using semiconductors has received much attention during the past decades because of its potential to address energy and environmental problems. Among various semiconductors,TiO2 has been regarded as the best and most widely investigated photocatalyst in the past 10 years. Based on the fundamentals of photocatalysis and surface chemistry of TiO2 nanomaterials,we herein summarize and discuss the achievements in the different surface modification strategies employed to date such as surface doping and sensitization,construction of surface heterojunctions,loading of nano-sized co-catalysts,increase in the accessible surface areas,and usage of surface F effects and exposure of highly reactive facets. Especially,the interesting synergistic effects of these different surface modification strategies deserve more attention in the near future. Studying these important advances in photocatalysis fundamentals,and surface chemistry and modification may offer new opportunities for designing highly efficient TiO2-based and non-TiO2-based photocatalysts for solar fuel production,environmental remediation,organic photosynthesis,and other related fields such as solar cell device fabrication,thermal catalysis,and separation and purification.展开更多
The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ...The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ground electronic state are taken to be the initial and target states, respectively, for the two molecular systems. The influences of the field peak amplitude and pulse duration on the population transfer process are discussed in detail. The pulse duration is required to be longer than 860 fs for the DF molecule to achieve a relatively high transfer probability （more than 80%）, while the one for the HF molecule is just required to be longer than 460 fs. Moreover, the intermediate level v=1 and the higher level v=3 may play more important roles in the two-photon resonance process for the DF molecule, compared to the roles in the process for the HF molecule.展开更多
Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labe...Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.展开更多
A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two p...A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two protected alcohol groups was synthesized by reacting with propargyl bromide. The alcohol groups were cleaved using a mixture of tetrahydrofuran and hydrochloric acid aqueous solution. In the last step the initiator was synthesized us- ing triflic anhydride in carbon tetrachloride. The initiator was characterized by 1H NMR and used for the polymerization of 2-ethyl-2-oxazoline which gives polymers with narrow distribution. For comparison a similar initiator with two tosylates was prepared and used for the polymerization of the monomer 2-ethyl-2-oxazoline, the resulting product has a wide molecular weight distribution and most of the initiator remains unreacted after 24 h which may be due to the steric hindrance between the two tosylate groups. To further explore the steric hindrance phenomenon, a linear tosylate initiator was synthesized, but still some of the initiator remains unreacted, illustrating that both steric hindrance and electrophilic balance affect the efficiency of the cationic ring-opening polymerization. All of the polymers were characterized in detail by using IH NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and size exclusion chromatography to confirm the purity and distribution of the polymers.展开更多
Perfluorooctane sulfonate （PFOS） has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertiliza...Perfluorooctane sulfonate （PFOS） has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish （Danio rerio）. Sperm were activated in aqueous media containing a range of PFOS concentrations （0, 0.09, 0.9 and 9 mg/L）. Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis （CASA） at 20, 40, 60, and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity （VCL）, and the mean angular displacement （MAD） of spermatozoa, but showed no influence on the straight- line velocity （VSL） or the angular path velocity （VAP）. Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish.展开更多
The geometric structures and vibration frequencies of para-chlorofluorobenzene(p-Cl FPh)in the first excited state of neutral and ground state of cation were investigated by resonanceenhanced multiphoton ionization an...The geometric structures and vibration frequencies of para-chlorofluorobenzene(p-Cl FPh)in the first excited state of neutral and ground state of cation were investigated by resonanceenhanced multiphoton ionization and slow electron velocity-map imaging.The infrared spectrum of S0 state and absorption spectrum for S1←S0 transition in p-Cl FPh were also recorded.Based on the one-color resonant two-photon ionization spectrum and two-color resonant two-photon ionization spectrum,we obtained the adiabatic excited-state energy of p-Cl FPh as 36302±4 cm^-1.In the two-color resonant two-photon ionization slow electron velocity-map imagin spectra,the accurate adiabatic ionization potential of p-Cl FPh was extrapolated as 72937±8 cm^-1 via threshold ionization measurement.In addition,FranckCondon simulation was performed to help us confidently ascertain the main vibrational modes in the S1 and D0 states.Furthermore,the mixing of vibrational modes between S0→S1 and S1→D0 has been analyzed.展开更多
AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN...AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN + pentobarbital sodium(PEN);2:LEAN + ISO;3:FAT + PEN;4:FAT + ISO.The animals were mechanically ventilated for 6 h.In vitro analyses of liver tissue included determination of HO-1 mRNA and protein expression as well as measurement of HO enzyme activity and immunohistochemical analyses.RESULTS:Compared to PEN treatment,ISO administration profoundly induced hepatic HO-1 mRNA and protein expression and significantly increased HO enzyme activity in lean Zucker rats.In contrast,no difference in HO-1 gene expression was observed after ISO or PEN anesthesia in obese Zucker rats.CONCLUSION:The present study demonstrates that ISO is an inducer of hepatic HO-1 gene expression in non-steatotic organs but failed to upregulate HO-1 in steatotic livers.展开更多
基金supported by the Industry and Research Collaborative Innovation Major Projects Of Guangzhou(201508020098)the National Natural Science Foundation of China(20906034+2 种基金21173088and 21207041)the State Key Laboratory of Advanced Technology for Material Synthesis and Processing,Wuhan University of Technology(2015-KF-7)~~
文摘As a green and sustainable technology,heterogeneous photocatalysis using semiconductors has received much attention during the past decades because of its potential to address energy and environmental problems. Among various semiconductors,TiO2 has been regarded as the best and most widely investigated photocatalyst in the past 10 years. Based on the fundamentals of photocatalysis and surface chemistry of TiO2 nanomaterials,we herein summarize and discuss the achievements in the different surface modification strategies employed to date such as surface doping and sensitization,construction of surface heterojunctions,loading of nano-sized co-catalysts,increase in the accessible surface areas,and usage of surface F effects and exposure of highly reactive facets. Especially,the interesting synergistic effects of these different surface modification strategies deserve more attention in the near future. Studying these important advances in photocatalysis fundamentals,and surface chemistry and modification may offer new opportunities for designing highly efficient TiO2-based and non-TiO2-based photocatalysts for solar fuel production,environmental remediation,organic photosynthesis,and other related fields such as solar cell device fabrication,thermal catalysis,and separation and purification.
文摘The isotope effects of XF （X=H, D） on the population transfer process via two-photon resonance excitation are investigated by solving the time-dependent SchrSdinger equation. The vibrational levels v=0 and 2 of the ground electronic state are taken to be the initial and target states, respectively, for the two molecular systems. The influences of the field peak amplitude and pulse duration on the population transfer process are discussed in detail. The pulse duration is required to be longer than 860 fs for the DF molecule to achieve a relatively high transfer probability （more than 80%）, while the one for the HF molecule is just required to be longer than 460 fs. Moreover, the intermediate level v=1 and the higher level v=3 may play more important roles in the two-photon resonance process for the DF molecule, compared to the roles in the process for the HF molecule.
基金Foundation item: Projects(51108197, 51205215) supported by the National Natural Science Foundation of ChinaProjects(2011J05135, 2011J01318) supported by the Natural Science Foundation of Fujian Province, China+1 种基金Project(11QZR08) supported by the Scientific Research Foundation of Overseas Chinese Affairs Office of the State Council,ChinaProject(10BS213) supported by the Scientific Research Foundation for Advanced Talents,Huaqiao University,China
文摘Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.
基金supported by the National Natural Scientific Foundation of China(No.21674107)the Fundamental Research Funds for the Central Universities(No.WK2340000066)the financial support from CASTWAS President’s PhD Fellowship Programme 2013
文摘A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne func- tionalized intermediate with two protected alcohol groups was synthesized by reacting with propargyl bromide. The alcohol groups were cleaved using a mixture of tetrahydrofuran and hydrochloric acid aqueous solution. In the last step the initiator was synthesized us- ing triflic anhydride in carbon tetrachloride. The initiator was characterized by 1H NMR and used for the polymerization of 2-ethyl-2-oxazoline which gives polymers with narrow distribution. For comparison a similar initiator with two tosylates was prepared and used for the polymerization of the monomer 2-ethyl-2-oxazoline, the resulting product has a wide molecular weight distribution and most of the initiator remains unreacted after 24 h which may be due to the steric hindrance between the two tosylate groups. To further explore the steric hindrance phenomenon, a linear tosylate initiator was synthesized, but still some of the initiator remains unreacted, illustrating that both steric hindrance and electrophilic balance affect the efficiency of the cationic ring-opening polymerization. All of the polymers were characterized in detail by using IH NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and size exclusion chromatography to confirm the purity and distribution of the polymers.
基金Supported by the National Natural Science Foundation of China(Nos.40632009,31300340)the Natural Science Foundation Project of Chongqing(No.cstc2015jcyjA20016)the Youth Top-notch Talent Cultivation Program of Chongqing Normal University(No.14CSBJ08)
文摘Perfluorooctane sulfonate （PFOS） has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish （Danio rerio）. Sperm were activated in aqueous media containing a range of PFOS concentrations （0, 0.09, 0.9 and 9 mg/L）. Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis （CASA） at 20, 40, 60, and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity （VCL）, and the mean angular displacement （MAD） of spermatozoa, but showed no influence on the straight- line velocity （VSL） or the angular path velocity （VAP）. Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish.
基金the National Natural Science Foundation of China(No.11674003,No.21873003,No.21503003,No.11704004,and No.61475001)Anhui Natural Science Foundation(No.1908085QA17)+1 种基金support from Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)(No.U1501501)Super Computation Center of Shenzhen。
文摘The geometric structures and vibration frequencies of para-chlorofluorobenzene(p-Cl FPh)in the first excited state of neutral and ground state of cation were investigated by resonanceenhanced multiphoton ionization and slow electron velocity-map imaging.The infrared spectrum of S0 state and absorption spectrum for S1←S0 transition in p-Cl FPh were also recorded.Based on the one-color resonant two-photon ionization spectrum and two-color resonant two-photon ionization spectrum,we obtained the adiabatic excited-state energy of p-Cl FPh as 36302±4 cm^-1.In the two-color resonant two-photon ionization slow electron velocity-map imagin spectra,the accurate adiabatic ionization potential of p-Cl FPh was extrapolated as 72937±8 cm^-1 via threshold ionization measurement.In addition,FranckCondon simulation was performed to help us confidently ascertain the main vibrational modes in the S1 and D0 states.Furthermore,the mixing of vibrational modes between S0→S1 and S1→D0 has been analyzed.
文摘AIM:To characterize the inductive effects of isoflurane(ISO) on hepatic heme oxygenase-1(HO-1) in an animal model of hepatic steatosis.METHODS:Lean(LEAN) and obese(FAT) Zucker rats were randomized into 4 groups:1:LEAN + pentobarbital sodium(PEN);2:LEAN + ISO;3:FAT + PEN;4:FAT + ISO.The animals were mechanically ventilated for 6 h.In vitro analyses of liver tissue included determination of HO-1 mRNA and protein expression as well as measurement of HO enzyme activity and immunohistochemical analyses.RESULTS:Compared to PEN treatment,ISO administration profoundly induced hepatic HO-1 mRNA and protein expression and significantly increased HO enzyme activity in lean Zucker rats.In contrast,no difference in HO-1 gene expression was observed after ISO or PEN anesthesia in obese Zucker rats.CONCLUSION:The present study demonstrates that ISO is an inducer of hepatic HO-1 gene expression in non-steatotic organs but failed to upregulate HO-1 in steatotic livers.
