Vascular etiology is the second most prevalent cause of cognitive impairment globally.Endothelin-1,which is produced and secreted by endothelial cells and astrocytes,is implicated in the pathogenesis of stroke.However...Vascular etiology is the second most prevalent cause of cognitive impairment globally.Endothelin-1,which is produced and secreted by endothelial cells and astrocytes,is implicated in the pathogenesis of stroke.However,the way in which changes in astrocytic endothelin-1 lead to poststroke cognitive deficits following transient middle cerebral artery occlusion is not well understood.Here,using mice in which astrocytic endothelin-1 was overexpressed,we found that the selective overexpression of endothelin-1 by astrocytic cells led to ischemic stroke-related dementia(1 hour of ischemia;7 days,28 days,or 3 months of reperfusion).We also revealed that astrocytic endothelin-1 overexpression contributed to the role of neural stem cell proliferation but impaired neurogenesis in the dentate gyrus of the hippocampus after middle cerebral artery occlusion.Comprehensive proteome profiles and western blot analysis confirmed that levels of glial fibrillary acidic protein and peroxiredoxin 6,which were differentially expressed in the brain,were significantly increased in mice with astrocytic endothelin-1 overexpression in comparison with wild-type mice 28 days after ischemic stroke.Moreover,the levels of the enriched differentially expressed proteins were closely related to lipid metabolism,as indicated by Kyoto Encyclopedia of Genes and Genomes pathway analysis.Liquid chromatography-mass spectrometry nontargeted metabolite profiling of brain tissues showed that astrocytic endothelin-1 overexpression altered lipid metabolism products such as glycerol phosphatidylcholine,sphingomyelin,and phosphatidic acid.Overall,this study demonstrates that astrocytic endothelin-1 overexpression can impair hippocampal neurogenesis and that it is correlated with lipid metabolism in poststroke cognitive dysfunction.展开更多
With gradual emergence of desertification reversal after inception of combative attempts in China, its evaluation which is based on solid identification is imperative. However, either identification or evaluation lack...With gradual emergence of desertification reversal after inception of combative attempts in China, its evaluation which is based on solid identification is imperative. However, either identification or evaluation lacks consensus and are limited in earlier studies. This paper endeavors to fill this gap by relying on a systematic review of recent studies. After a clarification of causal relation of identification and evaluation, an argument of indicators and models selection is presented taking sustainability, cost and benefits, public interest and individual behavior into account. At first, we emphasize the logical and sequential importance of identification as prerequisite of evaluation, and demonstrate that fundamental identification could be operated by both direct and indirect implementations, though direct implementation usually seems to be a favorite alternative. Here, we emphasize a consideration of sustainable development, cost and benefits, public interest and individual behaviors together, due to the hiatus of incorporating economic and ecological segments together, and the innate theoretical deficiencies on environmental products of traditional economic and ecological methods of evaluation. Thus, we conceptually merge the economic and ecological segments into one theoretical framework. However, no matter how elaborate the models is, there is an apparent gap of both identification and evaluation due to failure of dynamic interpretations, thereby, it may be future trend and urgency on models' elaboration.展开更多
Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IP...Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IPAc) with methanol(Me OH) were investigated. Among all the tested ILs, [Ps-mim]HSO_4 performed best and was used as catalyst for further studies. The reaction kinetics were carried out to correlate the parameters in a homogeneous second order kinetic model. It has been found that there is close agreement between the calculated and experimental values. The high-pressure batch reactive distillation experimental apparatus was set up in order to enhance the conversion of IPAc. A high conversion of IPAc of 99.4% was obtained under the optimal reaction conditions. The catalyst [Ps-mim]HSO_4 can be recycled easily by a rotary evaporator and reused without any further treatment. The catalyst had been repeatedly used for four times and no obvious changes in the structure of catalyst could be observed.展开更多
Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography(PET) studies on the neuroprotective effect of Tongxinluo on cereb...Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography(PET) studies on the neuroprotective effect of Tongxinluo on cerebral ischemia/reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion. 18F-fluorodeoxyglucose(FDG) small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia/reperfusion, glucose metabolism in the ischemic area was greater in rats that had received Tongxinluo than in those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia/reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. In addition, Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia/reperfusion injury and demonstrates that 18F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine.展开更多
In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridiniu...In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.展开更多
Global climate change has evolved from a scientific problem into an economic and political problem of worldwide interest.National perspectives play a crucial role in addressing climate change.Mutual understanding of p...Global climate change has evolved from a scientific problem into an economic and political problem of worldwide interest.National perspectives play a crucial role in addressing climate change.Mutual understanding of perspectives is necessary to result in rational policies and a consensus among stakeholders with divergent interests.Conceptual frameworks for understanding the problem of climate change in China,the largest developing country and the largest greenhouse gas emitter,are of great significance to national and international efforts to address the problems of climate change.Chinese perceptions of climate change as a sustainable development problem have recently been in tension with an emerging Western perspective that frames climate change as a security issue.This paper explores Chinese perceptions of climate change as expressed in recent governmental policy statements,public opinion surveys,and academic scholarship with a focus on publications in Chinese-language journals,often unfamiliar in the West.It looks at the relationship between Chinese research and policy and finds that the Chinese policy frame of climate change as a sustainable development problem draws from the body of domestic research and is reflective of the perspectives and multidisciplinary approach of Chinese researchers in areas of climate change.展开更多
Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss...Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.展开更多
In this study,cerebellar granule neurons were used to examine the role of nitric oxide on cell survival.The N-methyl-D-aspartic acid receptor antagonist,MK-801,and the soluble guanylate cyclase antagonist,1H-[1,2,4]ox...In this study,cerebellar granule neurons were used to examine the role of nitric oxide on cell survival.The N-methyl-D-aspartic acid receptor antagonist,MK-801,and the soluble guanylate cyclase antagonist,1H-[1,2,4]oxadiazolo-[4,3-a] quinoxalin-1-one,decreased cell viability,induced caspase-3,and decreased phosphorylated-Akt levels,suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons.After administration of sodium nitroprusside,an endogenous nitric oxide donor,cell viability recovered,caspase-3 expression was decreased,and phosphorylated-Akt levels increased.This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway.Moreover,endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.展开更多
BACKGROUND:Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries.The established ventral approach results in slight injuries,and is similar to mechanisms underlying...BACKGROUND:Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries.The established ventral approach results in slight injuries,and is similar to mechanisms underlying human brachial plexus root avulsion.OBJECTIVE:To analyze the effects of weight,age,and species on the success rate of brachial plexus root avulsion,and to determine the perfect method for establishing models of brachial plexus root avulsion.DESIGN,TIME AND SETTING:A randomized,block design was performed at the Laboratory of Professor Lihua Zhou,Zhongshan School of Medicine,Sun Yat-sen University,China from June 2008 to June 2009.MATERIALS:Sprague Dawley(SD) rats,golden hamsters,and BALb/C mice were used in the present study.METHODS:All animals were randomly subjected to classical brachial plexus root avulsion and modified brachial plexus root avulsion.MAIN OUTCOME MEASURES:Success rate of brachial plexus root avulsion.RESULTS:The success rate of brachial plexus root avulsion was greater in the modified group than in the classical group(P < 0.01).Moreover,the difference was significant in 15-day-old SD rats,5-week-old SD rats,and 3-month-old BALb/C mice(P < 0.01).The success rate of brachial plexus root avulsion was greater in the same weight,15-day-old juvenile SD rats,than in the 3-month-old BALb/C mice(classical group,P < 0.01;modified group,P < 0.05).The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group(P < 0.05).The success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group(P < 0.01).However,there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group(P > 0.05).CONCLUSION:Modified surgery to induce brachial plexus root avulsion significantly increases the success rate of model establishment.Species,age,and weight affect the success rate of brachial plexus root avulsion,and species plays an important role in the success rate.展开更多
Calling upon all nongovernmental sectors of the society is important to cope with the ecological crisis brought about by rapid development. Enterprises are the active agent of socialist market economic activities and ...Calling upon all nongovernmental sectors of the society is important to cope with the ecological crisis brought about by rapid development. Enterprises are the active agent of socialist market economic activities and possess a prominent position in the ecological civilization construction of the new age. Making use of the active agent role of enterprises and stimulating the green development of enterprises are essential to realizing the dream of a beautiful China. This paper discusses the development and management experiences of a typical ecological industrialization model, that of the Elion Resources Group in Inner Mongolia. Existing problems are disclosed, and feasible suggestions are given:(1) accelerate the registration of lands to protect legitimate rights and interests,(2) perfect the land-use administration system and make it cover all national land space,(3) perfect the natural resources management system, and(4) compile balance sheets of natural resources and strengthen accountabilities.展开更多
The contingent valuation method (CVM) is one of the main methods for evaluating non-market values of resources. It originated in the United States and was introduced into China during the 1980s and 1990s. However, app...The contingent valuation method (CVM) is one of the main methods for evaluating non-market values of resources. It originated in the United States and was introduced into China during the 1980s and 1990s. However, application of CVM in China is highly controversial based on three primary aspects: (1) the appropriate guidelines for CVM; (2) the elicitation techniques for willingness to pay (WTP); and (3) reliability and validity testing of CVM. The major objectives of this paper are to review the recent developments pertaining to guidelines, elicitation techniques, and reliability and validity testing for application of CVM, and to summarize the limitations of and measures for improving application of CVM in China. The applicability of CVM in China is discussed to enhance the future development of CVM in China.展开更多
[Objectives] This study was conducted to optimize the ethanol extraction technology of monoester alkaloids from Radix Aconiti Preparata. [Methods]On the basis of defined extraction times,ethanol concentration,ethanol ...[Objectives] This study was conducted to optimize the ethanol extraction technology of monoester alkaloids from Radix Aconiti Preparata. [Methods]On the basis of defined extraction times,ethanol concentration,ethanol times and extraction time were investigated by HPLC-MS combined with orthogonal test to optimize extraction process using the content of monoester alkaloids( the sum of benzoyl neoaconitine,benzoyl hypoaconitine and benzoyl aconitine) as an index.[Results]The optimum ethanol extraction technology was as follows: 75% ethanol,ethanol amount 25 times of the medicinal material,and each extraction for 1. 5 h.[Conclusions] The optimal extraction technology is simple,feasible,stable and reliable. It can provide reference for the industrial production and quality control of monoester alkaloids from Radix Aconiti Preparata.展开更多
Several examples of androdioecy appear to have evolved from dioecy and have low male frequency(<0.5).However,the evolutionary pathway to androdioecy in Oleaceae may come from hermaphroditism.Osmanthus fragrans L.ha...Several examples of androdioecy appear to have evolved from dioecy and have low male frequency(<0.5).However,the evolutionary pathway to androdioecy in Oleaceae may come from hermaphroditism.Osmanthus fragrans L.has a 1:1 sex ratio in nature populations.Significant differences are observed not only in flowering phenology but also in some floral traits between males and hermaphrodites.The protandry in the same population and the protogyny in the same plant may promote the xenogamy between genders.The majority of flower traits related with the pollen production are different between males and hermaphrodites.Males bear more flowering nodes,and more flowers per node,and larger anther in all three populations.This characteristic demonstrated that males have more male advantage than hermaphrodites.Population genetic structure of O.fragrans is genetically homogeneous at the species level,and most variations exist within a population.The percentage of variation among populations(13%)and between males and hermaphrodites(0%)is low.Moreover,genetic differentiation was very low between genders not only among populations but also in the same population.This genetic variation could be attributed to the occurrence of high levels of xenogamy between genders.Therefore,high male frequency and more male fitness advantage in males are the essential conditions for this mating system,which plays an important role during population reproduction and regeneration.The 1:1 sex ratio could be the result of integrative effects of sexual system,mating system,and reproductive success.展开更多
胰岛素是人类糖尿病治疗历史上具有里程碑意义的发现,解决了糖尿病患者高血糖不能控制的问题^([1]),在此基础上奠定了强化血糖控制可以延缓糖尿病慢性并发症发生的循证医学依据,并由此诞生了两大重量级研究成果,即糖尿病控制与合并症试...胰岛素是人类糖尿病治疗历史上具有里程碑意义的发现,解决了糖尿病患者高血糖不能控制的问题^([1]),在此基础上奠定了强化血糖控制可以延缓糖尿病慢性并发症发生的循证医学依据,并由此诞生了两大重量级研究成果,即糖尿病控制与合并症试验(Diabetes Control and Complications Trial,DCCT)和英国糖尿病前瞻性研究(United Kingdom Prospective Diabetes Study,UKPDS)^([2,3]).但是强化血糖控制在血糖达标的同时,发生低血糖的几率会增加.因此,人们期待模拟生理胰岛素的作用模式来开发相应的胰岛素剂型,其中模拟生理餐时胰岛素的作用需要开发一种起效迅速且没有尾峰效应的胰岛素,以保证餐后血糖能够平稳控制的同时不容易出现后续低血糖.在这样的需求下超速效胰岛素诞生了.展开更多
Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical.Herein,aiming at overcoming the co...Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical.Herein,aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity,rapid combination of photo-generated carriers and unstable structure,a novel Ag-bridged dual Z-scheme g-C_(3)N_(4)/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method.Results showed that Ag-AgI nanoparticles and three-dimensional(3D)BiOI microspheres were decorated highly uniformly on the 3D porous g-C_(3)N_(4) nanosheet,resulting in a higher specific surface area and abundant active sites.The optimized 3D porous dual Z-scheme g-C_(3)N_(4)/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline(TC)in water with approximately 91.8%degradation efficiency within 165 min,outperforming majority of the reported g-C_(3)N_(4)-based photocatalysts.Moreover,g-C_(3)N_(4)/BiOI/Ag-AgI exhibited good stability in terms of activity and structure.In-depth radical scavenging and electron paramagnetic resonance(EPR)analyses confirmed the relative contributions of various scavengers.Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework,fast electron transfer of dual Z-scheme heterojunction,desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas.Therefore,the 3D porous Z-scheme g-C_(3)N_(4)/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation.The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.展开更多
Astragalus is a species-rich genus occurring in the western arid habitats in China and its diversification and infrageneric relationships in this region remain unclear.In the present study,based on molecular data,we a...Astragalus is a species-rich genus occurring in the western arid habitats in China and its diversification and infrageneric relationships in this region remain unclear.In the present study,based on molecular data,we aim to(i) test whether Phyllolobium(previously treated as a subgenus Pogonophace in Astragalus) should be warranted;and(ii) date the origin of Phyllolobium and probable diversification of Astragalus sensu stricto(s.s.).We sequenced five species from Phyllolobium first and collected all related sequences from the genus,Astragalus s.s and their close relatives(Oxytropis and Caragana etc.).Our phylogenetic analyses suggested that all species of Phyllolobium comprise a monophyletic sister-group to genera of the subtribe Coluteinae.Molecular dating suggested that Phyllolobium and Astragalus s.s.originated around 8 and 10 million years ago.These two estimates are highly consistent with the intense uplifts of the Qinghai-Tibetan Plateau inferred from geological evidence.In addition,one section of Pogonophace(Sect.Robusti) was estimated to originate 2.5 million years ago and this section with a tendency for dry habitats seems to be evidence of Asian intensified aridity resulting from the intense uplift of the Qinghai-Tibetan Plateau.展开更多
The p-GaAs/n-InP heterojunction was fabricated by direct wafer bonding technology. The optimized atomic level contact between GaAs and InP is critical for getting good ohmic contact and removing the bubbles or voids a...The p-GaAs/n-InP heterojunction was fabricated by direct wafer bonding technology. The optimized atomic level contact between GaAs and InP is critical for getting good ohmic contact and removing the bubbles or voids at the interface, which is helpful to enhance the efficiency of wafer bonded multi-junction solar cells. Through the surface megasonic cleaning and the plasma treatment, we have achieved the high quality bonding interface without bubbles or voids and with interface resistivity of about 0.1 ohms/cm^2. A GaInP/GaAs//InGaAsP/InGaAs 4-junction solar cell was prepared with the high efficiency of 34.4%(AM0)at 1 sun.展开更多
基金financially supported by the National Natural Science Foundation of China,No.81303115,81774042 (both to XC)the Pearl River S&T Nova Program of Guangzhou,No.201806010025 (to XC)+3 种基金the Specialty Program of Guangdong Province Hospital of Chinese Medicine of China,No.YN2018ZD07 (to XC)the Natural Science Foundatior of Guangdong Province of China,No.2023A1515012174 (to JL)the Science and Technology Program of Guangzhou of China,No.20210201 0268 (to XC),20210201 0339 (to JS)Guangdong Provincial Key Laboratory of Research on Emergency in TCM,Nos.2018-75,2019-140 (to JS)
文摘Vascular etiology is the second most prevalent cause of cognitive impairment globally.Endothelin-1,which is produced and secreted by endothelial cells and astrocytes,is implicated in the pathogenesis of stroke.However,the way in which changes in astrocytic endothelin-1 lead to poststroke cognitive deficits following transient middle cerebral artery occlusion is not well understood.Here,using mice in which astrocytic endothelin-1 was overexpressed,we found that the selective overexpression of endothelin-1 by astrocytic cells led to ischemic stroke-related dementia(1 hour of ischemia;7 days,28 days,or 3 months of reperfusion).We also revealed that astrocytic endothelin-1 overexpression contributed to the role of neural stem cell proliferation but impaired neurogenesis in the dentate gyrus of the hippocampus after middle cerebral artery occlusion.Comprehensive proteome profiles and western blot analysis confirmed that levels of glial fibrillary acidic protein and peroxiredoxin 6,which were differentially expressed in the brain,were significantly increased in mice with astrocytic endothelin-1 overexpression in comparison with wild-type mice 28 days after ischemic stroke.Moreover,the levels of the enriched differentially expressed proteins were closely related to lipid metabolism,as indicated by Kyoto Encyclopedia of Genes and Genomes pathway analysis.Liquid chromatography-mass spectrometry nontargeted metabolite profiling of brain tissues showed that astrocytic endothelin-1 overexpression altered lipid metabolism products such as glycerol phosphatidylcholine,sphingomyelin,and phosphatidic acid.Overall,this study demonstrates that astrocytic endothelin-1 overexpression can impair hippocampal neurogenesis and that it is correlated with lipid metabolism in poststroke cognitive dysfunction.
基金financially supported by the 100 Talents Program of the Chinese Academy of Sciencesthe Key Project of the Chinese Academy of Sciences (No. KZZD-EW-04-05)+1 种基金the National Natural Science Foundation of China (40971278)the 2010 "Western Light" Project of the Chinese Academy of Sciences
文摘With gradual emergence of desertification reversal after inception of combative attempts in China, its evaluation which is based on solid identification is imperative. However, either identification or evaluation lacks consensus and are limited in earlier studies. This paper endeavors to fill this gap by relying on a systematic review of recent studies. After a clarification of causal relation of identification and evaluation, an argument of indicators and models selection is presented taking sustainability, cost and benefits, public interest and individual behavior into account. At first, we emphasize the logical and sequential importance of identification as prerequisite of evaluation, and demonstrate that fundamental identification could be operated by both direct and indirect implementations, though direct implementation usually seems to be a favorite alternative. Here, we emphasize a consideration of sustainable development, cost and benefits, public interest and individual behaviors together, due to the hiatus of incorporating economic and ecological segments together, and the innate theoretical deficiencies on environmental products of traditional economic and ecological methods of evaluation. Thus, we conceptually merge the economic and ecological segments into one theoretical framework. However, no matter how elaborate the models is, there is an apparent gap of both identification and evaluation due to failure of dynamic interpretations, thereby, it may be future trend and urgency on models' elaboration.
基金Supported by the National Natural Science Foundation of China(21576053,91534106,21306025)the International S&T Cooperation Program of China(2013DFR90540)+3 种基金the Science Foundation of Distinguished Young Scholars of Fujian(2014J06004)the New Century Excellent Talents in Fujian Province University(JA12014)the Natural Science Foundation of Fujian Province(2016J01689)the Key Project of Fujian Provincial Department of Science and Technology(2014Y0066)
文摘Five Br?nsted acidic ionic liquids(ILs) were prepared and characterized by FT-IR,~1H NMR and ^(13)C NMR. Their catalytic activities for the synthesis of 2-propanol(IPOH) via transesterification of isopropyl acetate(IPAc) with methanol(Me OH) were investigated. Among all the tested ILs, [Ps-mim]HSO_4 performed best and was used as catalyst for further studies. The reaction kinetics were carried out to correlate the parameters in a homogeneous second order kinetic model. It has been found that there is close agreement between the calculated and experimental values. The high-pressure batch reactive distillation experimental apparatus was set up in order to enhance the conversion of IPAc. A high conversion of IPAc of 99.4% was obtained under the optimal reaction conditions. The catalyst [Ps-mim]HSO_4 can be recycled easily by a rotary evaporator and reused without any further treatment. The catalyst had been repeatedly used for four times and no obvious changes in the structure of catalyst could be observed.
基金supported by the National Natural Science Foundation of China,No.81173435,81303115the Natural Science Foundation of Guangdong Province,No.S2013040016915the Postdoctoral Foundation of China,No.BBK42913K09,201003345
文摘Tongxinluo has been widely used in China for the treatment of acute stroke and for neuroprotection. However, there are few positron emission tomography(PET) studies on the neuroprotective effect of Tongxinluo on cerebral ischemia/reperfusion in small animals. In the present study, Tongxinluo superfine powder suspension or its vehicle was administered intragastrically to rats for 5 successive days before middle cerebral artery occlusion. 18F-fluorodeoxyglucose(FDG) small animal PET imaging showed that at 1 and 2 weeks after cerebral ischemia/reperfusion, glucose metabolism in the ischemic area was greater in rats that had received Tongxinluo than in those that had received the vehicle. Nissl staining showed that 2 weeks after cerebral ischemia/reperfusion, there was less neuronal loss in the prefrontal cortex in Tongxinluo-treated rats than in controls. In addition, Tongxinluo-treated animals showed better neurologic function and lower cerebral infarct volume than rats that received the vehicle. These findings suggest that Tongxinluo exhibits neuroprotective effects in cerebral ischemia/reperfusion injury and demonstrates that 18F-FDG small animal PET imaging is a useful tool with which to study the molecular pharmacology of traditional Chinese medicine.
基金supported by Natural Science Fund of Jiangsu Province (BK20141247, BK20140447)Exceptional Talent Project in Jiangsu Province (2015-XCL-035)+3 种基金University Science Research Project of Jiangsu Province (13KJB430005, 11KJA430008)funded by the Priority Academic Program development of Jiangsu Higher Education InstitutionsJiangsu Province universities' "blue and green blue project"financial support from the ARC (CE140100012, FT130100380, and DP170102267)
文摘In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin-MtTMPyP(Mt= Cobalt(Ⅱ), Manganese(Ⅲ), or Iron(Ⅲ); TMPyP = 5, 10, 15, 20-tetrakis(N-methylpyridinium-4-yl) porphyrin) intercalated into the layer of graphene oxide(GO) by the cooperative effects of electrostatic and π-π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2 D MtTMPyP/rGO_n were fabricated. The as-prepared 2 D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction(ORR) in an alkaline medium. The MtTMPyP/rGO_n hybrids, especially CoTMPyP/rGO_5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries.
基金financially supported by the Ministry of Science and Technology of the People’s Republic of China(No.2013CB956003)the 100 Talents Program of the Chinese Academy of Sciences+1 种基金the 2010"Western Light"Project of the Chinese Academy of Sciencesthe Key Project of the Chinese Academy of Sciences(No.KZZD-EW-04-05)
文摘Global climate change has evolved from a scientific problem into an economic and political problem of worldwide interest.National perspectives play a crucial role in addressing climate change.Mutual understanding of perspectives is necessary to result in rational policies and a consensus among stakeholders with divergent interests.Conceptual frameworks for understanding the problem of climate change in China,the largest developing country and the largest greenhouse gas emitter,are of great significance to national and international efforts to address the problems of climate change.Chinese perceptions of climate change as a sustainable development problem have recently been in tension with an emerging Western perspective that frames climate change as a security issue.This paper explores Chinese perceptions of climate change as expressed in recent governmental policy statements,public opinion surveys,and academic scholarship with a focus on publications in Chinese-language journals,often unfamiliar in the West.It looks at the relationship between Chinese research and policy and finds that the Chinese policy frame of climate change as a sustainable development problem draws from the body of domestic research and is reflective of the perspectives and multidisciplinary approach of Chinese researchers in areas of climate change.
基金supported by the National Basic Research Program of China (No. 2009CB421300): "The Processes of Oasifica-tion-Desertification and their Responding to Human Activities & Climatic Change and their Regulation in the Arid Region of China"
文摘Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.
基金the National Natural Science Foundation of China, No. 81070995Guangdong Provincial Science Foundation, No.05001726, 1050175
文摘In this study,cerebellar granule neurons were used to examine the role of nitric oxide on cell survival.The N-methyl-D-aspartic acid receptor antagonist,MK-801,and the soluble guanylate cyclase antagonist,1H-[1,2,4]oxadiazolo-[4,3-a] quinoxalin-1-one,decreased cell viability,induced caspase-3,and decreased phosphorylated-Akt levels,suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons.After administration of sodium nitroprusside,an endogenous nitric oxide donor,cell viability recovered,caspase-3 expression was decreased,and phosphorylated-Akt levels increased.This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway.Moreover,endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.
基金a Grant from Health Department of Guangdong Province in China,No. A2007169
文摘BACKGROUND:Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries.The established ventral approach results in slight injuries,and is similar to mechanisms underlying human brachial plexus root avulsion.OBJECTIVE:To analyze the effects of weight,age,and species on the success rate of brachial plexus root avulsion,and to determine the perfect method for establishing models of brachial plexus root avulsion.DESIGN,TIME AND SETTING:A randomized,block design was performed at the Laboratory of Professor Lihua Zhou,Zhongshan School of Medicine,Sun Yat-sen University,China from June 2008 to June 2009.MATERIALS:Sprague Dawley(SD) rats,golden hamsters,and BALb/C mice were used in the present study.METHODS:All animals were randomly subjected to classical brachial plexus root avulsion and modified brachial plexus root avulsion.MAIN OUTCOME MEASURES:Success rate of brachial plexus root avulsion.RESULTS:The success rate of brachial plexus root avulsion was greater in the modified group than in the classical group(P < 0.01).Moreover,the difference was significant in 15-day-old SD rats,5-week-old SD rats,and 3-month-old BALb/C mice(P < 0.01).The success rate of brachial plexus root avulsion was greater in the same weight,15-day-old juvenile SD rats,than in the 3-month-old BALb/C mice(classical group,P < 0.01;modified group,P < 0.05).The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group(P < 0.05).The success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group(P < 0.01).However,there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group(P > 0.05).CONCLUSION:Modified surgery to induce brachial plexus root avulsion significantly increases the success rate of model establishment.Species,age,and weight affect the success rate of brachial plexus root avulsion,and species plays an important role in the success rate.
基金financially supported by the National Key R&D Program (2016YFC0500909)the National Natural Science Foundation of China (Nos. 41601587 and 41471436)
文摘Calling upon all nongovernmental sectors of the society is important to cope with the ecological crisis brought about by rapid development. Enterprises are the active agent of socialist market economic activities and possess a prominent position in the ecological civilization construction of the new age. Making use of the active agent role of enterprises and stimulating the green development of enterprises are essential to realizing the dream of a beautiful China. This paper discusses the development and management experiences of a typical ecological industrialization model, that of the Elion Resources Group in Inner Mongolia. Existing problems are disclosed, and feasible suggestions are given:(1) accelerate the registration of lands to protect legitimate rights and interests,(2) perfect the land-use administration system and make it cover all national land space,(3) perfect the natural resources management system, and(4) compile balance sheets of natural resources and strengthen accountabilities.
基金supported by the One Hundred Talents Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China (No. 40971278)the "Western Light" Project of the Chinese Academy of Sciences, and the Key Project of the Chinese Academy of Sciences (No. KZZD-EW-04-05)
文摘The contingent valuation method (CVM) is one of the main methods for evaluating non-market values of resources. It originated in the United States and was introduced into China during the 1980s and 1990s. However, application of CVM in China is highly controversial based on three primary aspects: (1) the appropriate guidelines for CVM; (2) the elicitation techniques for willingness to pay (WTP); and (3) reliability and validity testing of CVM. The major objectives of this paper are to review the recent developments pertaining to guidelines, elicitation techniques, and reliability and validity testing for application of CVM, and to summarize the limitations of and measures for improving application of CVM in China. The applicability of CVM in China is discussed to enhance the future development of CVM in China.
基金Supported by Traditional Chinese Medicine Science and Technology Development Program of Shandong Province (2017-1982019-0400)Major Science and Technology Innovation Project of Shandong Province (2018CXGC1304)。
文摘[Objectives] This study was conducted to optimize the ethanol extraction technology of monoester alkaloids from Radix Aconiti Preparata. [Methods]On the basis of defined extraction times,ethanol concentration,ethanol times and extraction time were investigated by HPLC-MS combined with orthogonal test to optimize extraction process using the content of monoester alkaloids( the sum of benzoyl neoaconitine,benzoyl hypoaconitine and benzoyl aconitine) as an index.[Results]The optimum ethanol extraction technology was as follows: 75% ethanol,ethanol amount 25 times of the medicinal material,and each extraction for 1. 5 h.[Conclusions] The optimal extraction technology is simple,feasible,stable and reliable. It can provide reference for the industrial production and quality control of monoester alkaloids from Radix Aconiti Preparata.
基金supported by National Natural Science Foundation of China(Grant No.32072615 and 31902057)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02071).
文摘Several examples of androdioecy appear to have evolved from dioecy and have low male frequency(<0.5).However,the evolutionary pathway to androdioecy in Oleaceae may come from hermaphroditism.Osmanthus fragrans L.has a 1:1 sex ratio in nature populations.Significant differences are observed not only in flowering phenology but also in some floral traits between males and hermaphrodites.The protandry in the same population and the protogyny in the same plant may promote the xenogamy between genders.The majority of flower traits related with the pollen production are different between males and hermaphrodites.Males bear more flowering nodes,and more flowers per node,and larger anther in all three populations.This characteristic demonstrated that males have more male advantage than hermaphrodites.Population genetic structure of O.fragrans is genetically homogeneous at the species level,and most variations exist within a population.The percentage of variation among populations(13%)and between males and hermaphrodites(0%)is low.Moreover,genetic differentiation was very low between genders not only among populations but also in the same population.This genetic variation could be attributed to the occurrence of high levels of xenogamy between genders.Therefore,high male frequency and more male fitness advantage in males are the essential conditions for this mating system,which plays an important role during population reproduction and regeneration.The 1:1 sex ratio could be the result of integrative effects of sexual system,mating system,and reproductive success.
文摘胰岛素是人类糖尿病治疗历史上具有里程碑意义的发现,解决了糖尿病患者高血糖不能控制的问题^([1]),在此基础上奠定了强化血糖控制可以延缓糖尿病慢性并发症发生的循证医学依据,并由此诞生了两大重量级研究成果,即糖尿病控制与合并症试验(Diabetes Control and Complications Trial,DCCT)和英国糖尿病前瞻性研究(United Kingdom Prospective Diabetes Study,UKPDS)^([2,3]).但是强化血糖控制在血糖达标的同时,发生低血糖的几率会增加.因此,人们期待模拟生理胰岛素的作用模式来开发相应的胰岛素剂型,其中模拟生理餐时胰岛素的作用需要开发一种起效迅速且没有尾峰效应的胰岛素,以保证餐后血糖能够平稳控制的同时不容易出现后续低血糖.在这样的需求下超速效胰岛素诞生了.
基金supported by the National Natural Science Foundation of China(Nos.22106020 and 42122056)the KeyArea Research and Development Program of Guangdong Province(No.2020B1111350002)+1 种基金the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01Z032)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110718).
文摘Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical.Herein,aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity,rapid combination of photo-generated carriers and unstable structure,a novel Ag-bridged dual Z-scheme g-C_(3)N_(4)/BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method.Results showed that Ag-AgI nanoparticles and three-dimensional(3D)BiOI microspheres were decorated highly uniformly on the 3D porous g-C_(3)N_(4) nanosheet,resulting in a higher specific surface area and abundant active sites.The optimized 3D porous dual Z-scheme g-C_(3)N_(4)/BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline(TC)in water with approximately 91.8%degradation efficiency within 165 min,outperforming majority of the reported g-C_(3)N_(4)-based photocatalysts.Moreover,g-C_(3)N_(4)/BiOI/Ag-AgI exhibited good stability in terms of activity and structure.In-depth radical scavenging and electron paramagnetic resonance(EPR)analyses confirmed the relative contributions of various scavengers.Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework,fast electron transfer of dual Z-scheme heterojunction,desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas.Therefore,the 3D porous Z-scheme g-C_(3)N_(4)/BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation.The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications.
基金Supported by the Chinese Academy of Sciences (KSCX2-YW-2-069)National Natural Science Foundation of China (NSFC 30500035)Xinjiang Institute of Ecology and Geography, CAS, and China Scholarship Council (CSC) for supporting M.L. Zhang’s visit to the California Academy of Sciences
文摘Astragalus is a species-rich genus occurring in the western arid habitats in China and its diversification and infrageneric relationships in this region remain unclear.In the present study,based on molecular data,we aim to(i) test whether Phyllolobium(previously treated as a subgenus Pogonophace in Astragalus) should be warranted;and(ii) date the origin of Phyllolobium and probable diversification of Astragalus sensu stricto(s.s.).We sequenced five species from Phyllolobium first and collected all related sequences from the genus,Astragalus s.s and their close relatives(Oxytropis and Caragana etc.).Our phylogenetic analyses suggested that all species of Phyllolobium comprise a monophyletic sister-group to genera of the subtribe Coluteinae.Molecular dating suggested that Phyllolobium and Astragalus s.s.originated around 8 and 10 million years ago.These two estimates are highly consistent with the intense uplifts of the Qinghai-Tibetan Plateau inferred from geological evidence.In addition,one section of Pogonophace(Sect.Robusti) was estimated to originate 2.5 million years ago and this section with a tendency for dry habitats seems to be evidence of Asian intensified aridity resulting from the intense uplift of the Qinghai-Tibetan Plateau.
基金supported by the Shanghai Rising-Star Program (No. 14QB1402800)
文摘The p-GaAs/n-InP heterojunction was fabricated by direct wafer bonding technology. The optimized atomic level contact between GaAs and InP is critical for getting good ohmic contact and removing the bubbles or voids at the interface, which is helpful to enhance the efficiency of wafer bonded multi-junction solar cells. Through the surface megasonic cleaning and the plasma treatment, we have achieved the high quality bonding interface without bubbles or voids and with interface resistivity of about 0.1 ohms/cm^2. A GaInP/GaAs//InGaAsP/InGaAs 4-junction solar cell was prepared with the high efficiency of 34.4%(AM0)at 1 sun.
