The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to ...The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to form key intermediates with reactant molecules.The present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu_(2)O/Cu(Cu_(2)O/Cu/N-C)with a Cu_(2)O/dual electron acceptor interface using etched HKUST-1 as the precursor.A series of theoretical and experimental studies have demonstrated that the Cu_(2)O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron−hole pairs,but also facilitates the formation of the key intermediate[Cu_(2)O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal charges.As a result,the homo-coupling reaction can be effectively facilitated.The primary reason for the functional role of Cu_(2)O/Cu/N-C interface lies in the downward bending of energy band from Cu_(2)O to N-doped C layers,induced by the different work functions of Cu_(2)O,Cu and N-doped C layers.Consequently,Cu_(2)O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air atmosphere.The present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications.展开更多
A promising therapeutic strategy to promote the regeneration of injured axons in the adult central nervous system(CNS)is the transplantation of cells or tissues that can modify the local host environment and support...A promising therapeutic strategy to promote the regeneration of injured axons in the adult central nervous system(CNS)is the transplantation of cells or tissues that can modify the local host environment and support the growth of regenerating axons.展开更多
The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes ...The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes of the whole region. Using molecular geochemistry, fluid inclusion techniques and basin modeling, we studied the oil filling process of the Bashituo Oilfield that is located in the west of the Markit Slope. The molecular migration indexes, such as the methyldibenzothiophene ratio (4-/1-MDBT), trimethylnaphthalene ratio (TMNr) and pyrrolic nitrogen compounds content, decrease from west to east, indicating that the charging direction and migration pathways are from west to east. Lithological analysis and homogenization temperatures of saline fluid inclusions accompanied with oil fluid inclusions suggest that two charging periods occurred in the Devonian oil reservoir. Combining the burial history and heating history of well BT4, Basinmod 1D software modeling shows the two oil filling periods are from 290 Ma to 285 Ma and from l0 Ma to 4 Ma, respectively, and later oil filling dominates. This study may be helpful to understand the accumulation process and provide useful references for oil and gas exploration in the Markit Slope.展开更多
In order to distinguish the source and migration direction of natural gas by geochemical characteristics of butane,the components and carbon isotopes of natural gas from major hydrocarbonbearing basins in China were a...In order to distinguish the source and migration direction of natural gas by geochemical characteristics of butane,the components and carbon isotopes of natural gas from major hydrocarbonbearing basins in China were analyzed.The results showed that:(1) Oil-type gas has i-C 4 /n-C 4 0.8,δ 13 C butane -28‰,δ 13 C i-butane -27‰,δ 13 C n-butane -28.5‰,whereas coal-type gas has i-C 4 /n-C 4 0.8,δ 13 C butane -25.5‰,δ 13 C i-butane -24‰,δ 13 C n-butane -26‰.(2) When δ 13 C i-butane-δ 13 C n-butane is greater than 0,the maturity of oil-type gas is generally more than 2.4% and that of coal-type gas is greater than 1.4%,whereas when the difference is less than 0,the maturity of oil-type gas is generally less than 1.1% and that of coal-type gas is less than 0.8%.(3) When natural gas migrates through dense cap rocks,the value of i-C 4 /n-C 4 increases,whereas when it migrates laterally along a reservoir,the value of i-C 4 /n-C 4 decreases.(4) Sapropelic transition zone gas with composition and carbon isotopic signatures similar to those of oil-type gas in the low thermal evolution stage is found to have a relatively high butane content.(5) The values of i-C 4 /n-C 4 and δ 13 C n-butane δ 13 C i-butane of gas which has suffered biological degradation are significantly higher than those obtained from thermogenic and bio-thermocatalytic transition zone gas.Thus,natural gas of different genetic types can be recognized through component analysis and carbon isotopic signatures of butane,the natural gas maturity can be estimated from the difference in carbon isotopic content between isobutane and n-butane,and the migration direction of natural gas can be determined from i-C 4 /n-C 4 ratios and transport conditions,which can also be used to thermogenic and bio-thermocatalytic transition zone gas.展开更多
Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplanta...Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction,angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action,and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke.We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.展开更多
The Upper Permian Changxing dolomite reservoirs serves as one of the most important gas and oil reservoirs in the NE Sichuan Basin. Determining the dolomitizing fluid's pathway is regarded as the key to solve the "d...The Upper Permian Changxing dolomite reservoirs serves as one of the most important gas and oil reservoirs in the NE Sichuan Basin. Determining the dolomitizing fluid's pathway is regarded as the key to solve the "dolomite problem" and further petroleum exploration. Outcrop samples from Upper Permian Changhsingian Panlongdong Section were studied using oxygen isotopic analysis, cathodoluminescence(CL) and major element analysis, in an attempt to determine the migration path way and properties of the dolomitizing fluid. Of the Changxing dolomite, the δ18O values ranged from-3.494‰ to-5.481‰, which decreased from the top layer to the bottom in the section; the MgO contents varied from 9.24% to 21.43%, CaO contents from 28.65% to 39.87%, the CaO/MgO ratio from 1.40 to 4.31 and the Mn O contents from 0.004% to 0.009 8%. The Mg O contents showed a downwardly decreasing trend in the section, while the Ca O/Mg O showed an opposite rule. All of the dolomites looked dull or dark when they were exposed to the electron beam of the cathodoluminescence device. None of the fine-to medium grained dolomite showed a banded structure. Given that dolomitizing fluid's salinity decreased during the dolomitization process in its pathway, we concluded that the dolomitizing fluid migrated downwardly in Changxing Formation after excluding the possibility of deep burial or meteoric-marine mixing-water influences. As the dolomitizing fluid's pathway has always been difficult to be determined in highly dolomitized Formation, this study showed an important application of oxygen isotope values in resolving this problem.展开更多
The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of gCN.Thus,the controllable migration of charge carriers is a rational strategy to suppress the charge recombination a...The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of gCN.Thus,the controllable migration of charge carriers is a rational strategy to suppress the charge recombination and facilitate charge separation.Herein,an ethylenediamine modified g-C_(3)N_(4)displays improved photocatalytic activity.The excellent charge separation efficiency is confirmed to be a key factor for the enhancement.The TEM observation after photo-depositing Pt nanoparticles and DFT calculations verify the accumulation of electrons on some areas of g-C_(3)N_(4)surface.The increased-NH_(2)groups significantly tune the electronic structure of g-C_(3)N_(4)after the modification.The generation of midgap states also affects the charge separation.Our reports provide a simple method to manage the migration of charge carriers and enable electrons directional transfer,which suppresses the recombination and improves the photocatalytic activity.展开更多
基金supported by the Xuzhou Key Research and Development Program(Social Development)(No.KC23298)the National Natural Science Foundation of China(No.22271122)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20211549)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_2903).
文摘The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction,but also their ability to form key intermediates with reactant molecules.The present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu_(2)O/Cu(Cu_(2)O/Cu/N-C)with a Cu_(2)O/dual electron acceptor interface using etched HKUST-1 as the precursor.A series of theoretical and experimental studies have demonstrated that the Cu_(2)O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron−hole pairs,but also facilitates the formation of the key intermediate[Cu_(2)O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal charges.As a result,the homo-coupling reaction can be effectively facilitated.The primary reason for the functional role of Cu_(2)O/Cu/N-C interface lies in the downward bending of energy band from Cu_(2)O to N-doped C layers,induced by the different work functions of Cu_(2)O,Cu and N-doped C layers.Consequently,Cu_(2)O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air atmosphere.The present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications.
基金supported by NIH NS055976Craig H.Neilsen Foundation 280850
文摘A promising therapeutic strategy to promote the regeneration of injured axons in the adult central nervous system(CNS)is the transplantation of cells or tissues that can modify the local host environment and support the growth of regenerating axons.
基金supported by the Natural Science Foundation of China (Grant No.40972089)the Foundation of the State Key Laboratory of Petroleum Resources and Prospecting (Grant No.PRPDX2008-01)
文摘The Markit Slope is an important area for the petroleum exploration in the Tarim Basin. Elucidation of the oil filling history of discovered oilfields has great significance for recognizing the accumulation processes of the whole region. Using molecular geochemistry, fluid inclusion techniques and basin modeling, we studied the oil filling process of the Bashituo Oilfield that is located in the west of the Markit Slope. The molecular migration indexes, such as the methyldibenzothiophene ratio (4-/1-MDBT), trimethylnaphthalene ratio (TMNr) and pyrrolic nitrogen compounds content, decrease from west to east, indicating that the charging direction and migration pathways are from west to east. Lithological analysis and homogenization temperatures of saline fluid inclusions accompanied with oil fluid inclusions suggest that two charging periods occurred in the Devonian oil reservoir. Combining the burial history and heating history of well BT4, Basinmod 1D software modeling shows the two oil filling periods are from 290 Ma to 285 Ma and from l0 Ma to 4 Ma, respectively, and later oil filling dominates. This study may be helpful to understand the accumulation process and provide useful references for oil and gas exploration in the Markit Slope.
基金supported by NSFC (Grant No. 41202100)the National Science and Technology Major Projects(Grant No. 2008ZX05007-003)
文摘In order to distinguish the source and migration direction of natural gas by geochemical characteristics of butane,the components and carbon isotopes of natural gas from major hydrocarbonbearing basins in China were analyzed.The results showed that:(1) Oil-type gas has i-C 4 /n-C 4 0.8,δ 13 C butane -28‰,δ 13 C i-butane -27‰,δ 13 C n-butane -28.5‰,whereas coal-type gas has i-C 4 /n-C 4 0.8,δ 13 C butane -25.5‰,δ 13 C i-butane -24‰,δ 13 C n-butane -26‰.(2) When δ 13 C i-butane-δ 13 C n-butane is greater than 0,the maturity of oil-type gas is generally more than 2.4% and that of coal-type gas is greater than 1.4%,whereas when the difference is less than 0,the maturity of oil-type gas is generally less than 1.1% and that of coal-type gas is less than 0.8%.(3) When natural gas migrates through dense cap rocks,the value of i-C 4 /n-C 4 increases,whereas when it migrates laterally along a reservoir,the value of i-C 4 /n-C 4 decreases.(4) Sapropelic transition zone gas with composition and carbon isotopic signatures similar to those of oil-type gas in the low thermal evolution stage is found to have a relatively high butane content.(5) The values of i-C 4 /n-C 4 and δ 13 C n-butane δ 13 C i-butane of gas which has suffered biological degradation are significantly higher than those obtained from thermogenic and bio-thermocatalytic transition zone gas.Thus,natural gas of different genetic types can be recognized through component analysis and carbon isotopic signatures of butane,the natural gas maturity can be estimated from the difference in carbon isotopic content between isobutane and n-butane,and the migration direction of natural gas can be determined from i-C 4 /n-C 4 ratios and transport conditions,which can also be used to thermogenic and bio-thermocatalytic transition zone gas.
基金supported by the Natural Science Foundation of Heilongjiang Province of China,No.H2015083a grant from Higher Education Reform Project of Mudanjaing Medical University of China,No.2013016
文摘Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction,angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action,and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke.We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.
基金supported by the National Natural Science Foundation of China (Nos.40472015, 40802001, and 41372121)the State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation at CDUT (PL200801)
文摘The Upper Permian Changxing dolomite reservoirs serves as one of the most important gas and oil reservoirs in the NE Sichuan Basin. Determining the dolomitizing fluid's pathway is regarded as the key to solve the "dolomite problem" and further petroleum exploration. Outcrop samples from Upper Permian Changhsingian Panlongdong Section were studied using oxygen isotopic analysis, cathodoluminescence(CL) and major element analysis, in an attempt to determine the migration path way and properties of the dolomitizing fluid. Of the Changxing dolomite, the δ18O values ranged from-3.494‰ to-5.481‰, which decreased from the top layer to the bottom in the section; the MgO contents varied from 9.24% to 21.43%, CaO contents from 28.65% to 39.87%, the CaO/MgO ratio from 1.40 to 4.31 and the Mn O contents from 0.004% to 0.009 8%. The Mg O contents showed a downwardly decreasing trend in the section, while the Ca O/Mg O showed an opposite rule. All of the dolomites looked dull or dark when they were exposed to the electron beam of the cathodoluminescence device. None of the fine-to medium grained dolomite showed a banded structure. Given that dolomitizing fluid's salinity decreased during the dolomitization process in its pathway, we concluded that the dolomitizing fluid migrated downwardly in Changxing Formation after excluding the possibility of deep burial or meteoric-marine mixing-water influences. As the dolomitizing fluid's pathway has always been difficult to be determined in highly dolomitized Formation, this study showed an important application of oxygen isotope values in resolving this problem.
基金supported by Shenzhen Key Laboratory of Solid State Batteries(ZDSYS20180208184346531)Guangdong Provincial Key Laboratory of Energy Materials for Electric Power(2018B030322001)+3 种基金Guangdong Provincial Key Laboratory of Catalysis(2020B121201002)Shenzhen Clean Energy Research Institute(CERI-KY-2019-003)the National Natural Science Foundation of China(2017M611446)supported by the Core Research Facilities at SUSTech that receives support from a Presidential fund and the Development and Reform Commission of Shenzhen Municipality。
文摘The random mobility of charge carriers is a main factor causing the low photocatalytic efficiency of gCN.Thus,the controllable migration of charge carriers is a rational strategy to suppress the charge recombination and facilitate charge separation.Herein,an ethylenediamine modified g-C_(3)N_(4)displays improved photocatalytic activity.The excellent charge separation efficiency is confirmed to be a key factor for the enhancement.The TEM observation after photo-depositing Pt nanoparticles and DFT calculations verify the accumulation of electrons on some areas of g-C_(3)N_(4)surface.The increased-NH_(2)groups significantly tune the electronic structure of g-C_(3)N_(4)after the modification.The generation of midgap states also affects the charge separation.Our reports provide a simple method to manage the migration of charge carriers and enable electrons directional transfer,which suppresses the recombination and improves the photocatalytic activity.