Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme ch...Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme challenges due to the susceptibility of the copper cathode in a reduction environment.Herein,a small molecule modulation electrodeposition strategy is introduced that regulates the structure of Cubased materials through modification with citric acid(CA)ligands,aiming for highly active and selective ECSH.The as-prepared EDCu-CA electrode achieves more than 97%alkyne conversion and 99%olefin selectivity.In-situ Raman and Auger electron spectroscopy(AES)data provide evidence that active Cu^(+)sites can stably exist in the EDCu-CA during the catalytic process.Density functional theory(DFT)calculations indicate that the modulation by CA contributes to maintaining Cu in a positive valence state,and Cu^(+)can inhibit the over-hydrogenation of olefins.Moreover,by utilizing a large-area electrode for longterm electrolysis,g-level conversion and a 92%separation yield of olefin can be achieved,demonstrating a viable application prospect.This study offers a promising route for designing Cu-based catalysts for the highly selective electrocata lytic conversion of organic substrates to value-added chemicals in water.展开更多
Irritable bowel syndrome(IBS) is a highly prevalent medical condition that adversely affects patient quality of life and constitutes a significant economic burden on healthcare resources. A large proportion of patient...Irritable bowel syndrome(IBS) is a highly prevalent medical condition that adversely affects patient quality of life and constitutes a significant economic burden on healthcare resources. A large proportion of patients suffer from the constipation subtype of IBS(IBS-C), most commonly afflicting older individuals and those with a lower socioeconomic status. Conventional pharmacologic and nonpharmacologic treatment options have limited efficacies and/or significant adverse events, which lead to increased long-term health care expenditures. Failure to effectively treat IBS-C patients over the past decades has largely been due to a poor understanding of disease pathophysiology, lack of a global view of the patient, and an inappropriate selection of patients and treatment endpoints in clinical trials. In recent years, however, more effective and safer drugs have been developed for the treatment of IBS-C. The advancement in the area of pharmacologic treatment is based on new knowledge of the pathophysiologic basis of IBS-C and the development of drugs with increased selectivity within pharmacologic classes with recognized efficacies. This narrative review covers the spectrum of available drugs and their mechanisms of action, as well as the efficacy and safety profiles of each as determined in relevant clinical trials that have investigated treatment options for IBS-C and chronic constipation. A brief summary of laxative-based treatment options is presented, followed by up-to-date assessments for three classes of drugs: prokinetics, prosecretory agents, and bile acid modulators.展开更多
In this study,a series of metal-organic frameworks(MOFs)NH_(2)-UiO-66-x HAc catalysts were synthesized by solvothermal method using acetic acid(HAc)as a modulator,and were applied to the cycloaddition of CO_(2)and epi...In this study,a series of metal-organic frameworks(MOFs)NH_(2)-UiO-66-x HAc catalysts were synthesized by solvothermal method using acetic acid(HAc)as a modulator,and were applied to the cycloaddition of CO_(2)and epichlorohydrin(EPIC)under ambient pressure.Influences of the modulation by HAc on morphologies and structures of the MOFs are demonstrated via PXRD,FESEM,FTIR,N_(2)adsorption-desorption,XPS and ^(1)H NMR characterizations.The results show that the MOFs containing mesoporous pores can be prepared by adjusting the concentration of HAc.By optimizing the amount of HAc added,the specific surface area of NH_(2)-UiO-66-8 HAc is as high as 879.17 m^(2)·g^(-1),which is 28.3%higher than that of the original MOFs.And the evaluation of catalytic performance showed that HAc modulation enhanced the activity of NH_(2)-UiO-66-x HAc under mild conditions.The exposure of Lewis acid sites,increased specific surface area and porosity via the modulation of HAc defective ligand can be supposed the key factors to determine the enhanced catalytic activities.In addition,considering the influence of gas concentration on the reaction,the concept of TOP(Turnover of Pressure,defined as the mass of conversions of a unit mass catalyst under unit pressure and unit time)was first proposed in this article.展开更多
To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid...To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.展开更多
Valproic acid （VPA） has been a first-choice drug for clinical treatment of epilepsy and manic disorder. For decades, its phar- macological action was believed to act on inhibition of gam- ma-aminobutyric acid （GABA...Valproic acid （VPA） has been a first-choice drug for clinical treatment of epilepsy and manic disorder. For decades, its phar- macological action was believed to act on inhibition of gam- ma-aminobutyric acid （GABA） transaminase, in turn, increas- ing GABA in inhibitory synapses. However, in recent years, VPA has been investigated on other therapeutic actions. Those investigations demonstrate that VPA shows neuroprotective ef- fects by promoting neurogenesis, neuronal differentiation, and neuroregeneration （Foti et al., 2013）.展开更多
Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare...Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare regular square-like BiOCl nanoplates with high exposure{001}facets.The results of characterizations showed that reduced-size square-like BiOCl nanoplates were with high exposure{001}facets.Nitro explosives,including p-nitrophenol(PNP),2,4-dinitrophenol(2,4-DNP),2,4,6-trinitrophenol(2,4,6-TNP),and 2,4,6-trinitrotoluene(TNT),were selected to inquire into the catalytic properties of pre pared samples under simulated irradiation.The catalytic performance of BC-10 was the best.In particular,BC-10 could thoroughly degrade four nitro explosives solutions,namely,PNP,2,4-DNP,2,4,6-TNP,and TNT(20 mg L^(−1))under simulated irradiation in 50,90,90,and 90 min,respectively;photocatalytic mechanism was exhaustively discussed.Photoelectrochemical,in additon to electron paramagnetic reso nance characterizations,suggested that the intrinsic factor for the superior photocatalytic performance was the enhancement of the transfer and separation effciency of photogenerated charge carriers derived from the BiOCl{001}active facets.Moreover,the primary active substance in the system was superoxide radicals.This study may provide new insights on the preparation of effcient catalysts for degrading nitro explosives.展开更多
The solvothermal reaction of ZrCl_(4) with a benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxylic acid (L1) linker molecule in the presence of a trifluoro acetic acid modulator afforded a UiO-66 type of metal organic fram...The solvothermal reaction of ZrCl_(4) with a benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxylic acid (L1) linker molecule in the presence of a trifluoro acetic acid modulator afforded a UiO-66 type of metal organic framework (MOF) (IITG-5,IITG = Indian Institute of Technology,Guwahati).The synthesized MOF material was characterized in detail with the help of PXRD,FE-SEM,FT-IR,EDX and elemental analyses.The material showed high thermal stability up to 390 ℃ in air atmosphere.This porous material (surface area = 1228 m^(2) g^(-1)) also displayed significant chemical stability in various solvents.The thermally activated compound (IITG-5a) exhibited excellent detectability towards Hg^(2+) in aqueous medium and various nitro-antibiotics (nitrofurazone and nitrofurantoin) in MeOH.Besides the fast response (1 min for all analytes),very low limits of detection (LODs) were observed for the sensing of all the targeted analytes (LOD for Hg^(2+),nitrofurazone and nitrofurantoin were 5,156.7 and 96.3 nM,respectively).A paper strip-based sensing technique was developed for all the three analytes.Interestingly,for the sensing of all the above-mentioned analytes,IITG-5a featured excellent reusability of up to five consecutive cycles without loss of its sensing efficiency.Mechanisms for all the sensing actvities were elaborately explored by means of DFT calculations and analytical methods.展开更多
Metal-organic frameworks(MOFs)are attracting increasing interests as photocatalysts for solar-driven hydrogen production from water.This paper reports on a comparative study of using either acetic acid(AA)or trifluoro...Metal-organic frameworks(MOFs)are attracting increasing interests as photocatalysts for solar-driven hydrogen production from water.This paper reports on a comparative study of using either acetic acid(AA)or trifluoroacetic acid(TFA)as the representative UiO-66 organic modulators for synthesizing visible light responsive UiO-66(Zr)-X(X:NH_(2) or NO_(2))photocatalysts for water splitting.The results show that photocatalytic hydrogen generation from a water/methanol mixture can be improved by varying the nature and amount of the modulator employed to prepare the different UiO-66(Zr)-X(X:NH_(2) or NO_(2))solid derivatives.UiO-66(Zr)-NH_(2) was the most active photocatalyst,followed by UiO-66(Zr)-NO_(2),both prepared with 12 equivalents of AA with respect to the organic ligand.This UiO-66(Zr)-NH_(2) solid was more active than the parent MOF in photocatalytic overall water splitting(OWS)(H_(2) and O_(2) production of 450 and 160μmol·g^(-1),respectively,in 5 h;apparent quantum yield(AQY)at 400 nm of 0.06%)in the absence of methanol and compares favourably with analogous reports.Information on the photocatalytic activity of the most active solids of both series was obtained by means of a series of techniques,including ultraviolet-visible(UV-vis)diffuse reflectance,X-ray photoelectron spectroscopy(XPS),laser flash photolysis(LFP),electron spin resonance(ESR),photoluminescence and photoelectrochemical measurements together with density functional theory(DFT)calculations.The results showed that organic acid modulators can be used to enhance the photocatalytic activity of missing linker UiO-66 defective materials in solar-powered water splitting.展开更多
基金financially supported by the National Natural Science Foundation of China(NSFC)(22179056,22172018)the Liaoning Revitalization Talents Program(XLYC2002097,1807210)+2 种基金the Key Projects of Liaoning Provincial Education Department(JYTZD2023001)the Fundamental Research Funds for the Central Universities(DUT23LAB611)Yingkou Talents Program。
文摘Selective electrocatalytic semi-hydrogenation(ECSH)of alkynes in water using Cu catalysts is highly relevant for the production of value-added chemicals.However,achieving high olefin selectivity still poses extreme challenges due to the susceptibility of the copper cathode in a reduction environment.Herein,a small molecule modulation electrodeposition strategy is introduced that regulates the structure of Cubased materials through modification with citric acid(CA)ligands,aiming for highly active and selective ECSH.The as-prepared EDCu-CA electrode achieves more than 97%alkyne conversion and 99%olefin selectivity.In-situ Raman and Auger electron spectroscopy(AES)data provide evidence that active Cu^(+)sites can stably exist in the EDCu-CA during the catalytic process.Density functional theory(DFT)calculations indicate that the modulation by CA contributes to maintaining Cu in a positive valence state,and Cu^(+)can inhibit the over-hydrogenation of olefins.Moreover,by utilizing a large-area electrode for longterm electrolysis,g-level conversion and a 92%separation yield of olefin can be achieved,demonstrating a viable application prospect.This study offers a promising route for designing Cu-based catalysts for the highly selective electrocata lytic conversion of organic substrates to value-added chemicals in water.
文摘Irritable bowel syndrome(IBS) is a highly prevalent medical condition that adversely affects patient quality of life and constitutes a significant economic burden on healthcare resources. A large proportion of patients suffer from the constipation subtype of IBS(IBS-C), most commonly afflicting older individuals and those with a lower socioeconomic status. Conventional pharmacologic and nonpharmacologic treatment options have limited efficacies and/or significant adverse events, which lead to increased long-term health care expenditures. Failure to effectively treat IBS-C patients over the past decades has largely been due to a poor understanding of disease pathophysiology, lack of a global view of the patient, and an inappropriate selection of patients and treatment endpoints in clinical trials. In recent years, however, more effective and safer drugs have been developed for the treatment of IBS-C. The advancement in the area of pharmacologic treatment is based on new knowledge of the pathophysiologic basis of IBS-C and the development of drugs with increased selectivity within pharmacologic classes with recognized efficacies. This narrative review covers the spectrum of available drugs and their mechanisms of action, as well as the efficacy and safety profiles of each as determined in relevant clinical trials that have investigated treatment options for IBS-C and chronic constipation. A brief summary of laxative-based treatment options is presented, followed by up-to-date assessments for three classes of drugs: prokinetics, prosecretory agents, and bile acid modulators.
基金financially supported by the Anhui Provincial Natural Science Foundation(1908085MB42)the National Natural Science Foundation of China(51372062)。
文摘In this study,a series of metal-organic frameworks(MOFs)NH_(2)-UiO-66-x HAc catalysts were synthesized by solvothermal method using acetic acid(HAc)as a modulator,and were applied to the cycloaddition of CO_(2)and epichlorohydrin(EPIC)under ambient pressure.Influences of the modulation by HAc on morphologies and structures of the MOFs are demonstrated via PXRD,FESEM,FTIR,N_(2)adsorption-desorption,XPS and ^(1)H NMR characterizations.The results show that the MOFs containing mesoporous pores can be prepared by adjusting the concentration of HAc.By optimizing the amount of HAc added,the specific surface area of NH_(2)-UiO-66-8 HAc is as high as 879.17 m^(2)·g^(-1),which is 28.3%higher than that of the original MOFs.And the evaluation of catalytic performance showed that HAc modulation enhanced the activity of NH_(2)-UiO-66-x HAc under mild conditions.The exposure of Lewis acid sites,increased specific surface area and porosity via the modulation of HAc defective ligand can be supposed the key factors to determine the enhanced catalytic activities.In addition,considering the influence of gas concentration on the reaction,the concept of TOP(Turnover of Pressure,defined as the mass of conversions of a unit mass catalyst under unit pressure and unit time)was first proposed in this article.
基金supported by National Natural Science Foundation of China [grant number 91841301]Fundamental Research Funds for the Central Universities [grant number YJ201791]。
文摘To improve the cracking behavior of hydrocarbon,Ni-Mo/SiO_(2) bimetallic catalysts were synthesized by different preparation methods(sol-gel,co-impregnation and single-impregnation) and added the additives(citric acid,polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above.The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance,and the properties of Ni-Mo/SiO_(2) catalyst were characterized by N_(2) absorption-desorption,XRD,XPS,H_(2)-TPR,NH_(3)-TPD,in-situ IR of NH_(3) desorption,HRTEM and STEM-mapping so as to study the structure-activity relationship.The catalyst synthesized via sol-gel method showed the best conversion and heat sink,being 81.8% and 3.81 MJ/kg,which was closely related to strong mutual effect between active components and SiO_(2) as well as strong acid sites.Besides,the introduction of additives by sol-gel method has an affirmative influence on properties of Ni-Mo/SiO_(2) catalysts,being that the acidity(more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species(Ni and Mo),thereby enhancing the catalytic activity.At 750℃,the conversion(89.3%) as well as heat sink(3.99 MJ/kg) of MCH cracking obtained an optimum over Ni-Mo/SiO_(2) catalyst with addition of citric acid.
基金supported by the Agency for Science and Technology(A*STAR)intramural funding for the Integrative Neuroscience Programme,Singapore Institute for Clinical Sciences
文摘Valproic acid （VPA） has been a first-choice drug for clinical treatment of epilepsy and manic disorder. For decades, its phar- macological action was believed to act on inhibition of gam- ma-aminobutyric acid （GABA） transaminase, in turn, increas- ing GABA in inhibitory synapses. However, in recent years, VPA has been investigated on other therapeutic actions. Those investigations demonstrate that VPA shows neuroprotective ef- fects by promoting neurogenesis, neuronal differentiation, and neuroregeneration （Foti et al., 2013）.
基金support received from the Natural Science Foundation of China(21875192)Outstanding Youth Science and Technology Talents Program of Sichuan(19JCQN0085)Open Project of State Key Laboratory of Environment-friendly Energy Materials(19fksy04).
文摘Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare regular square-like BiOCl nanoplates with high exposure{001}facets.The results of characterizations showed that reduced-size square-like BiOCl nanoplates were with high exposure{001}facets.Nitro explosives,including p-nitrophenol(PNP),2,4-dinitrophenol(2,4-DNP),2,4,6-trinitrophenol(2,4,6-TNP),and 2,4,6-trinitrotoluene(TNT),were selected to inquire into the catalytic properties of pre pared samples under simulated irradiation.The catalytic performance of BC-10 was the best.In particular,BC-10 could thoroughly degrade four nitro explosives solutions,namely,PNP,2,4-DNP,2,4,6-TNP,and TNT(20 mg L^(−1))under simulated irradiation in 50,90,90,and 90 min,respectively;photocatalytic mechanism was exhaustively discussed.Photoelectrochemical,in additon to electron paramagnetic reso nance characterizations,suggested that the intrinsic factor for the superior photocatalytic performance was the enhancement of the transfer and separation effciency of photogenerated charge carriers derived from the BiOCl{001}active facets.Moreover,the primary active substance in the system was superoxide radicals.This study may provide new insights on the preparation of effcient catalysts for degrading nitro explosives.
基金funding from SERB(India)via the grant number EEQ/2016/000012.
文摘The solvothermal reaction of ZrCl_(4) with a benzo[1,2-b:4,5-b′]dithiophene-2,6-dicarboxylic acid (L1) linker molecule in the presence of a trifluoro acetic acid modulator afforded a UiO-66 type of metal organic framework (MOF) (IITG-5,IITG = Indian Institute of Technology,Guwahati).The synthesized MOF material was characterized in detail with the help of PXRD,FE-SEM,FT-IR,EDX and elemental analyses.The material showed high thermal stability up to 390 ℃ in air atmosphere.This porous material (surface area = 1228 m^(2) g^(-1)) also displayed significant chemical stability in various solvents.The thermally activated compound (IITG-5a) exhibited excellent detectability towards Hg^(2+) in aqueous medium and various nitro-antibiotics (nitrofurazone and nitrofurantoin) in MeOH.Besides the fast response (1 min for all analytes),very low limits of detection (LODs) were observed for the sensing of all the targeted analytes (LOD for Hg^(2+),nitrofurazone and nitrofurantoin were 5,156.7 and 96.3 nM,respectively).A paper strip-based sensing technique was developed for all the three analytes.Interestingly,for the sensing of all the above-mentioned analytes,IITG-5a featured excellent reusability of up to five consecutive cycles without loss of its sensing efficiency.Mechanisms for all the sensing actvities were elaborately explored by means of DFT calculations and analytical methods.
基金support of PRE2019-089877 funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future.V.D-C.is grateful to the European Union’s Horizon 2020 Research and Innovation Program project MOF2H2(GA No.101084131)for the financial supportthe Centre informatique national de l'enseignement supérieur(CINES)Supercomputing facilities and the local ICGM clusters.I.V.thanks the support of grant PID2020-115010RB-I00 funded by MCIN/AEI/10.13039/501100011033support of grant PID2021-123856OBI00 funded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe.
文摘Metal-organic frameworks(MOFs)are attracting increasing interests as photocatalysts for solar-driven hydrogen production from water.This paper reports on a comparative study of using either acetic acid(AA)or trifluoroacetic acid(TFA)as the representative UiO-66 organic modulators for synthesizing visible light responsive UiO-66(Zr)-X(X:NH_(2) or NO_(2))photocatalysts for water splitting.The results show that photocatalytic hydrogen generation from a water/methanol mixture can be improved by varying the nature and amount of the modulator employed to prepare the different UiO-66(Zr)-X(X:NH_(2) or NO_(2))solid derivatives.UiO-66(Zr)-NH_(2) was the most active photocatalyst,followed by UiO-66(Zr)-NO_(2),both prepared with 12 equivalents of AA with respect to the organic ligand.This UiO-66(Zr)-NH_(2) solid was more active than the parent MOF in photocatalytic overall water splitting(OWS)(H_(2) and O_(2) production of 450 and 160μmol·g^(-1),respectively,in 5 h;apparent quantum yield(AQY)at 400 nm of 0.06%)in the absence of methanol and compares favourably with analogous reports.Information on the photocatalytic activity of the most active solids of both series was obtained by means of a series of techniques,including ultraviolet-visible(UV-vis)diffuse reflectance,X-ray photoelectron spectroscopy(XPS),laser flash photolysis(LFP),electron spin resonance(ESR),photoluminescence and photoelectrochemical measurements together with density functional theory(DFT)calculations.The results showed that organic acid modulators can be used to enhance the photocatalytic activity of missing linker UiO-66 defective materials in solar-powered water splitting.
