新陈代谢是生物的基本生理过程。生态学代谢理论(metabolic theory of ecology)基于生物个体大小和环境温度对个体新陈代谢过程的影响,使用尺度推移(scaling)的方法来解释多种生态学格局和过程。James Borwn等将这一理论用于解释物种多...新陈代谢是生物的基本生理过程。生态学代谢理论(metabolic theory of ecology)基于生物个体大小和环境温度对个体新陈代谢过程的影响,使用尺度推移(scaling)的方法来解释多种生态学格局和过程。James Borwn等将这一理论用于解释物种多样性的大尺度格局,并从机制上解释了物种多样性与环境温度的关系。这一理论提出了两个明确的预测:(1)物种多样性的对数与绝对温度的倒数之间呈线性关系;(2)这一线性关系的斜率为–0.6至–0.7。这一理论自提出以来,饱受争议,经过了正反两方面经验数据的检验,目前仍未形成一致的结论。虽然这一理论仍面临着一些有待解决的问题,但它以崭新的思路和方法有别于以往的基于统计学方法的研究。人们过去对该理论的实证检验忽略了两个重要的约束条件,即除温度以外的环境条件处于理想状态和群落处于平衡状态,而这两个约束条件是理解该理论的基础。本文对生态学代谢理论的理论框架、预测和含义,以及以往的检验结果进行阐述,在此基础上提出了作者对该理论的若干认识和未来研究中应考虑的若干问题。展开更多
We previously demonstrated using noninvasive technologies that the interferon-gamma （IFN-γ） receptor complex is preassembled [ 1 ]. In this report we determined how the receptor complex is preassembled and how the ...We previously demonstrated using noninvasive technologies that the interferon-gamma （IFN-γ） receptor complex is preassembled [ 1 ]. In this report we determined how the receptor complex is preassembled and how the ligand-mediated conformational changes occur. The interaction of Statl with IFN-γR1 results in a conformational change localized to IFN- γR1. Jakl but not Jak2 is required for the two chains of the IFN-γ receptor complex （IFN-γR1 and IFN-γR2） to interact; however, the presence of both Jakl and Jak2 is required to see any ligand-dependant conformational change. Two IFN- γR2 chains interact through species-specific determinants in their extracellular domains. Finally, these determinants also participate in the interaction of IFN-γR2 with IFN-γR1. These results agree with a detailed model of the IFN-γ receptor that requires the receptor chains to be pre-associated constitutively for the receptor to be active.展开更多
Chemiluminescence (CL) phenomenon of hydrogen peroxide with potassium permanganate in the presence of sodium hydrogen carbonate was reported.Effects of the surfactant on the CL system were investigated.Nonionic surfac...Chemiluminescence (CL) phenomenon of hydrogen peroxide with potassium permanganate in the presence of sodium hydrogen carbonate was reported.Effects of the surfactant on the CL system were investigated.Nonionic surfactants could effectively increase the CL signal.Radical scavengers and organic reagents such as nitro blue tetrazolium chloride (NBT),cytochrome c,sodium azide,ascorbic acid,thiourea,tert-butanol and dimethyl sulphoxide were used to study the emitting species.CL emission spectrum was recorded and the results showed that the maximal emission wavelengths of NaHCO3-H2O2-KMnO4 system were 440 and 634 nm.The mechanism was discussed based on electron spin resonance (ESR) spectra,fluorescence spectra and UV-vis absorption spectra.The addition of rhodamine B or uranine into this CL system enhanced the CL signal.It was due to part of the energy transfer from singlet oxygen and excited triplet dimers of two CO2 molecules to rhodamine B or uranine.The CL could be induced by excited rhodamine B or uranine.展开更多
Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study...Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study,single-atom Ag was successfully anchored on ultrathin carbon nitride(UTCN)via thermal polymerization,the catalyst obtained is called AgUTCN.The Ag hardly changed the carbon nitride's layered and porous physical structure.AgUTCN exhibited efficient visible-light photocatalytic performances in the degradation of various recalcitrant pollutants,eliminations of 85% were achieved by visible-light irradiation for 1hr.Doping with Ag improved the photocatalytic performance of UTCN by narrowing the forbidden band gap from 2.49 to 2.36 e V and suppressing electron-hole pair recombination.In addition,Ag doping facilitated O_(2) adsorption on UTCN by decreasing the adsorption energy from -0.2 to -2.22 e V and favored the formation of O_(2)^(·-).Electron spin resonance and radical-quenching experiments showed that O_(2)^(·-)was the major reactive species in the degradation of Acetaminophen(paracetamol,APAP).展开更多
Chlorine has been widely used in different advanced oxidation processes(AOPs)for micropollutants removal.In this study,different chlorine-based AOPs,namely medium pressure(MP)UV/chlorine,low pressure(LP)UV/chlorine,an...Chlorine has been widely used in different advanced oxidation processes(AOPs)for micropollutants removal.In this study,different chlorine-based AOPs,namely medium pressure(MP)UV/chlorine,low pressure(LP)UV/chlorine,and in-situ chlorination,were compared for carbamazepine(CBZ)removal efficiency,energy consumption,and disinfection by-products(DBPs)formation.All three processes could achieve nearly 100%CBZ removal,while the reaction time needed by in-situ chlorination was double the time required by UV/chlorine processes.The energy consumed per magnitude of CBZ removed(EE/O)of MP UV/chlorine was 13 times higher than that of LP UV/chlorine,and relative to that of in-situ chlorination process.Accordingly,MP and LP UV/chlorine processes generated one to two orders of magnitude more hydroxyl radicals(^(·)OH)and reactive chlorine species(RCS)than in-situ chlorination.Besides,RCS were the dominant reactive species,contributing to 78.3%,75.6%,and 71.6% of CBZ removal in MP,LP UV/chlorine,and in-situ chlorination,respectively.According to the Gibbs free energy barriers between CBZ and RCS/^(·)OH calculated based on density functional theory(DFT),RCS had more reaction routes with CBZ and showed lower energy barrier in the main CBZ degradation pathways like epoxidation and formation of iminostilbene.When applied to secondary wastewater effluent,UV/chlorine and in-situ chlorination produced overall DBPs ranging from 104.77 to 135.41μg/L.However,the production of chlorate during UV/chlorine processes was 15 times higher than that during in-situ chlorination.展开更多
Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this ...Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B species.The nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+) diffusion pathway,and accommodating volume expansion during repeated charging/discharging.The abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−) and reduce the diffusion barrier.The BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1) at 0.05 A g^(−1) and superior stability(96.5% retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the literature.As the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+) and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,respectively.Meanwhile,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+) migration,resulting in good rate performance.Therefore,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.展开更多
A comparative study of the needle-to-liquid plasma in the continuous mode with DC and AC excitations is detailed in this paper. All plasmas studied here are shown to be glow discharges. This study is based on measurem...A comparative study of the needle-to-liquid plasma in the continuous mode with DC and AC excitations is detailed in this paper. All plasmas studied here are shown to be glow discharges. This study is based on measurements of several key parameters, including electrical energy, optical emission intensities of active species, rotational and vibrational temperatures, and temperatures of the needle and liquid electrodes. AC plasmas can produce 1.2～5 times higher excited state active species than DC plasmas under the same dissipated power. AC excited liquid plasmas have the highest energy utilization efficiency among the three systems （AC excited plasmas, DC excited plasmas with water anode and DC excited plasmas with water cathode）; most of the energy is used to produce useful species rather than to heat the electrodes and plasmas.展开更多
Upconversion nanosensitizers have been widely considered to have important applications in the treatment of major diseases such as tumors and the utilization of solar energy.Majority of the efforts so far have been fo...Upconversion nanosensitizers have been widely considered to have important applications in the treatment of major diseases such as tumors and the utilization of solar energy.Majority of the efforts so far have been focused on improving the efficiency of energy transfer(ET)between upconversion nanoparticles(UCNPs)and the anchored sensitizers with premise that high ET efficiency will lead to high acceptor efficacy.This premise is,however,proved by our current work to be invalid for commonly used load.Interaction between adjacent sensitizing molecules was found to be critical which undermines the amount of excited monomer sensitizers and thus fades the efficacy.Here NaYF_(4):Yb^(3+),Er^(3+)UCNPs and rose bengal(RB)photosensitizer molecules were used as the model energy donors and acceptors,respectively.Contrary to monotonous increase of the ET efficiency from UCNPs to RB species with increasing RB loading,acceptor efficacy characterized by the reactive oxygen species,as well as the RB fluorescence,exhibits bizarre dependence on the RB loading.The underlying mechanism was well studied by the steady-state and time-resolved spectroscopy of a series of samples.RB aggregates are believed to be responsible for the severe deviation between the ET efficiency and acceptor efficacy.The conclusion was validated by in vitro test where the photodynamic therapy with the most monomer RB in UCNPs-RB nanosensitizers kills 35.8%more cells than that with the highest RB loading.This understanding sheds light on construction of new ET based nanosystems for broad applications,such as medicine,solar energy utilization and optical storage.展开更多
文摘新陈代谢是生物的基本生理过程。生态学代谢理论(metabolic theory of ecology)基于生物个体大小和环境温度对个体新陈代谢过程的影响,使用尺度推移(scaling)的方法来解释多种生态学格局和过程。James Borwn等将这一理论用于解释物种多样性的大尺度格局,并从机制上解释了物种多样性与环境温度的关系。这一理论提出了两个明确的预测:(1)物种多样性的对数与绝对温度的倒数之间呈线性关系;(2)这一线性关系的斜率为–0.6至–0.7。这一理论自提出以来,饱受争议,经过了正反两方面经验数据的检验,目前仍未形成一致的结论。虽然这一理论仍面临着一些有待解决的问题,但它以崭新的思路和方法有别于以往的基于统计学方法的研究。人们过去对该理论的实证检验忽略了两个重要的约束条件,即除温度以外的环境条件处于理想状态和群落处于平衡状态,而这两个约束条件是理解该理论的基础。本文对生态学代谢理论的理论框架、预测和含义,以及以往的检验结果进行阐述,在此基础上提出了作者对该理论的若干认识和未来研究中应考虑的若干问题。
文摘We previously demonstrated using noninvasive technologies that the interferon-gamma （IFN-γ） receptor complex is preassembled [ 1 ]. In this report we determined how the receptor complex is preassembled and how the ligand-mediated conformational changes occur. The interaction of Statl with IFN-γR1 results in a conformational change localized to IFN- γR1. Jakl but not Jak2 is required for the two chains of the IFN-γ receptor complex （IFN-γR1 and IFN-γR2） to interact; however, the presence of both Jakl and Jak2 is required to see any ligand-dependant conformational change. Two IFN- γR2 chains interact through species-specific determinants in their extracellular domains. Finally, these determinants also participate in the interaction of IFN-γR2 with IFN-γR1. These results agree with a detailed model of the IFN-γ receptor that requires the receptor chains to be pre-associated constitutively for the receptor to be active.
基金support from the National Natural Science Foundation of China (209350002)the National Basic Research Program of China (2007CB714507)
文摘Chemiluminescence (CL) phenomenon of hydrogen peroxide with potassium permanganate in the presence of sodium hydrogen carbonate was reported.Effects of the surfactant on the CL system were investigated.Nonionic surfactants could effectively increase the CL signal.Radical scavengers and organic reagents such as nitro blue tetrazolium chloride (NBT),cytochrome c,sodium azide,ascorbic acid,thiourea,tert-butanol and dimethyl sulphoxide were used to study the emitting species.CL emission spectrum was recorded and the results showed that the maximal emission wavelengths of NaHCO3-H2O2-KMnO4 system were 440 and 634 nm.The mechanism was discussed based on electron spin resonance (ESR) spectra,fluorescence spectra and UV-vis absorption spectra.The addition of rhodamine B or uranine into this CL system enhanced the CL signal.It was due to part of the energy transfer from singlet oxygen and excited triplet dimers of two CO2 molecules to rhodamine B or uranine.The CL could be induced by excited rhodamine B or uranine.
基金supported by the Shenzhen Science,Technology and Innovation Commission(No.JCYJ20200109142829123)the National Natural Science Foundation of China(No.52022049)。
文摘Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light absorbance.In this study,single-atom Ag was successfully anchored on ultrathin carbon nitride(UTCN)via thermal polymerization,the catalyst obtained is called AgUTCN.The Ag hardly changed the carbon nitride's layered and porous physical structure.AgUTCN exhibited efficient visible-light photocatalytic performances in the degradation of various recalcitrant pollutants,eliminations of 85% were achieved by visible-light irradiation for 1hr.Doping with Ag improved the photocatalytic performance of UTCN by narrowing the forbidden band gap from 2.49 to 2.36 e V and suppressing electron-hole pair recombination.In addition,Ag doping facilitated O_(2) adsorption on UTCN by decreasing the adsorption energy from -0.2 to -2.22 e V and favored the formation of O_(2)^(·-).Electron spin resonance and radical-quenching experiments showed that O_(2)^(·-)was the major reactive species in the degradation of Acetaminophen(paracetamol,APAP).
基金financial supports provided by Natural Sciences and Engineering Research Council of Canada(NSERC)Collaborative Research and Development(CRD)program and an NSERC Discovery grantfinancial supports provided by EPCOR Water Services,Canada Foundation for Innovation(CFI)John R.Evans Leaders Fund+2 种基金financial support provided by the China Scholarship Council(No.201906420017)Xuzhou Science and Technology Bureau(No.KC20055)Jiangsu Provincial Department of Science and Technology(No.BE2021632)。
文摘Chlorine has been widely used in different advanced oxidation processes(AOPs)for micropollutants removal.In this study,different chlorine-based AOPs,namely medium pressure(MP)UV/chlorine,low pressure(LP)UV/chlorine,and in-situ chlorination,were compared for carbamazepine(CBZ)removal efficiency,energy consumption,and disinfection by-products(DBPs)formation.All three processes could achieve nearly 100%CBZ removal,while the reaction time needed by in-situ chlorination was double the time required by UV/chlorine processes.The energy consumed per magnitude of CBZ removed(EE/O)of MP UV/chlorine was 13 times higher than that of LP UV/chlorine,and relative to that of in-situ chlorination process.Accordingly,MP and LP UV/chlorine processes generated one to two orders of magnitude more hydroxyl radicals(^(·)OH)and reactive chlorine species(RCS)than in-situ chlorination.Besides,RCS were the dominant reactive species,contributing to 78.3%,75.6%,and 71.6% of CBZ removal in MP,LP UV/chlorine,and in-situ chlorination,respectively.According to the Gibbs free energy barriers between CBZ and RCS/^(·)OH calculated based on density functional theory(DFT),RCS had more reaction routes with CBZ and showed lower energy barrier in the main CBZ degradation pathways like epoxidation and formation of iminostilbene.When applied to secondary wastewater effluent,UV/chlorine and in-situ chlorination produced overall DBPs ranging from 104.77 to 135.41μg/L.However,the production of chlorate during UV/chlorine processes was 15 times higher than that during in-situ chlorination.
基金Jiangsu Key Lab of Biomass Energy and Material,Grant/Award Number:JSBEMS‐202101National Natural Science Foundation of China,Grant/Award Numbers:51902162,51902162+4 种基金National Key R&D Program of China,Grant/Award Number:2022YFB4201904Foundation of Jiangsu Key Lab of Biomass Energy and Material,Grant/Award Number:JSBEM‐S‐202101National Key R&D Program,Grant/Award Number:2022YFB4201904Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest Resources,the International Innovation Center for Forest Chemicals and Materialsanjing Forestry University。
文摘Biomass‐derived carbon is a promising electrode material in energy storage devices.However,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a challenge.In this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B species.The nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+) diffusion pathway,and accommodating volume expansion during repeated charging/discharging.The abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−) and reduce the diffusion barrier.The BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1) at 0.05 A g^(−1) and superior stability(96.5% retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the literature.As the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+) and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,respectively.Meanwhile,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+) migration,resulting in good rate performance.Therefore,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.
基金supported by National Natural Science Foundation of China(No.51207027)Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China
文摘A comparative study of the needle-to-liquid plasma in the continuous mode with DC and AC excitations is detailed in this paper. All plasmas studied here are shown to be glow discharges. This study is based on measurements of several key parameters, including electrical energy, optical emission intensities of active species, rotational and vibrational temperatures, and temperatures of the needle and liquid electrodes. AC plasmas can produce 1.2～5 times higher excited state active species than DC plasmas under the same dissipated power. AC excited liquid plasmas have the highest energy utilization efficiency among the three systems （AC excited plasmas, DC excited plasmas with water anode and DC excited plasmas with water cathode）; most of the energy is used to produce useful species rather than to heat the electrodes and plasmas.
基金Project supported by the National Natural Science Foundation of China(51972052,11604043,11604044,51772122,11674316)Scientific and Technological Developing Scheme of Jilin Province(20190201243JC)+5 种基金Science and Technology Research Project of Education Department of Jilin Province(JJKH20211275KJ)the Fundamental Research Funds for the Central Universities(2412019FZ033)the 111 Project(B13013)Netherlands Organization for Scientific Research in the framework of the Fund New Chemical Innovation(731.015.206)EU H2020-MSCA-ITN-ETN Action program,ISPIC(675743)EU H2020-MSCA-RISE Action program,CANCER(777682)。
文摘Upconversion nanosensitizers have been widely considered to have important applications in the treatment of major diseases such as tumors and the utilization of solar energy.Majority of the efforts so far have been focused on improving the efficiency of energy transfer(ET)between upconversion nanoparticles(UCNPs)and the anchored sensitizers with premise that high ET efficiency will lead to high acceptor efficacy.This premise is,however,proved by our current work to be invalid for commonly used load.Interaction between adjacent sensitizing molecules was found to be critical which undermines the amount of excited monomer sensitizers and thus fades the efficacy.Here NaYF_(4):Yb^(3+),Er^(3+)UCNPs and rose bengal(RB)photosensitizer molecules were used as the model energy donors and acceptors,respectively.Contrary to monotonous increase of the ET efficiency from UCNPs to RB species with increasing RB loading,acceptor efficacy characterized by the reactive oxygen species,as well as the RB fluorescence,exhibits bizarre dependence on the RB loading.The underlying mechanism was well studied by the steady-state and time-resolved spectroscopy of a series of samples.RB aggregates are believed to be responsible for the severe deviation between the ET efficiency and acceptor efficacy.The conclusion was validated by in vitro test where the photodynamic therapy with the most monomer RB in UCNPs-RB nanosensitizers kills 35.8%more cells than that with the highest RB loading.This understanding sheds light on construction of new ET based nanosystems for broad applications,such as medicine,solar energy utilization and optical storage.
