The mass application of Hall thrusters poses the need for a diagnostic method of ionization mechanism in the discharge channel to boost the iteration and optimization of thruster design.This work presents an Optical E...The mass application of Hall thrusters poses the need for a diagnostic method of ionization mechanism in the discharge channel to boost the iteration and optimization of thruster design.This work presents an Optical Emission Spectroscopy (OES) method for diagnostics of the contribution of different ionization mechanisms and the flux of ions in different valences in the discharge channel of a Hall thruster.The emission spectra in the discharge channel are analyzed by jointly utilizing a collisional-radiative model,an ionization-excitation model,and a flux-conservation model.It is found that the intensities of some spectral lines can be converted into the reaction rates of collision processes,e.g.,electron-induced excitation and ionization processes.The latter can further be used to determine the evolutions of particle fluxes by utilizing the conservation law of matter.The novel method is demonstrated on a kilo-watt Hall thruster.The evolutions of several parameters are determined using this method along the discharge channel,including the ionization rates of different mechanisms,particle fluxes,particle densities,and particle velocities.This novel method can be further developed by being jointly utilized with spectral imaging and tomography techniques,enabling diagnostics of multi-dimensional distributions of the above-mentioned parameters in the discharge channel and near-field plume.展开更多
The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympath...The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympathetic nervous system(PNS),also affects bone remodeling,so it is of worth to investigate if the divalent cations influence PNS activity.Of note,these cations are key co-enzymes modulating glucose metabolism.Aerobic glycolysis rather than oxidative phosphorylation favors osteogenesis of mesenchymal stem cells(MSCs),so it is of interest to study the effects of these cations on glucose metabolic pathway.Prior to biological function assessment,the tolerance limits of the divalent metal cations(Mg^(2+),Zn^(2+),and Ca^(2+))and their combinations were profiled.In terms of direct effects,these divalent cations potentially enhanced migration and adhesion capability of MSCs through upregulating Tgf-β1 and Integrin-β1 levels.Interestingly,the divalent cations alone did not influence osteogenesis and aerobic glycolysis of undifferentiated MSCs.However,once the osteogenic differentiation of MSCs was initiated by neurotransmitters or osteogenic differentiation medium,the osteogenesis of MSCs could be significantly promoted by the divalent cations,which was accompanied by the improved aerobic glycolysis.In terms of indirect effects,the divalent cations significantly upregulated levels of sensory nerve derived CGRP,PNS produced choline acetyltransferase and type H vessels,while significantly tuned down sympathetic activity in the defect zone in rats,thereby contributing to significantly increased bone formation relative to the control group.Together,the divalent cations favor bone regeneration via modulation of sensory-autonomic nervous systems and promotion of aerobic glycolysis-driven osteogenesis of MSCs after osteogenic initiation by neurotransmitters.展开更多
The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitatio...The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitation conditions on fluorescent properties of Eu^(2+) are studied at 77 and 298 K.The coordination number of Eu^(2+) at different sites is obtained.The green and red emission bands arise from Eu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.展开更多
Microbial desalination cell （MDC） is a promis- ing technology to desalinate water and generate electrical power simultaneously. The objectives of this study were to investigate the desalination performance of monova...Microbial desalination cell （MDC） is a promis- ing technology to desalinate water and generate electrical power simultaneously. The objectives of this study were to investigate the desalination performance of monovalent and divalent cations in the MDC, and discuss the effect of ion characteristics, ion concentrations, and electrical characteristics. Mixed salt solutions of NaC1, MgC12, KC1, and CaC12 with the same concentration were used in the desalination chamber to study removal of cations. Results showed that in the mixed salt solutions, the electrodialysis desalination rates of cations were： Ca2＋ 〉 Mg2＋ 〉 Na＋ 〉 K＋. Higher ionic charges and smaller hydrated ionic radii resulted in higher desalination rates of the cations, in which the ionic charge was more important than the hydrated ionic radius. Mixed solutions of NaC1 and MgC12 with different concentrations were used in the desalination chamber to study the effect of ion concentra- tions. Results showed that when ion concentrations ofNa＋ were one-fifth to five times of Mg2~, ion concentration influenced the dialysis more profoundly than electrodia- lysis. With the current densities below a certain value, charge transfer efficiencies became very low and the dialysis was the main process responsible for the desalination. And the phosphate transfer from the anode chamber and potassium transfer from the cathode chamber could balance 1%-3% of the charge transfer in the MDC.展开更多
Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk s...Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe^(2+),Mg^(2+),Zn^(2+),Mn^(2+),Cu^(2+)and Ca^(2+)from FeCl_(2),MgSO_(4),ZnSO_(4),MnCl_(2),CuSO_(4)and CaCl_(2).The POs were inhibited by Fe^(2+)at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.展开更多
WTFZ] The interaction of adenosine triphosphate with divalent metal ions is important in biochemical functions. The effects of pH and metal ions Mg 2+ , Ca 2+ , Zn 2+ , Mn 2+ , and Co 2+ on the c...WTFZ] The interaction of adenosine triphosphate with divalent metal ions is important in biochemical functions. The effects of pH and metal ions Mg 2+ , Ca 2+ , Zn 2+ , Mn 2+ , and Co 2+ on the chemical shift of the phosphate group of ATP have been studied using Nuclear Magnetic Resonance. The chemical shift of the β-phosphate of ATP is the most sensitive to pH. Ca 2+ and Mg 2+ bind with the α- and β-phosphate groups of ATP. Zn 2+ binds to the adenosine ring hydrogen as well as to phosphate. The paramagnetic ions Mn 2+ and Co 2+ do not cause chemical shifts of the phosphate or proton peak. Mn 2+ and Co 2+ broaden the resonance peak only.[展开更多
Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of ...Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of acid-base pairs within a polybenzimidazole matrix through controlled sulfonation.By leveraging these intermolecular interactions,we enhance the Li^(+)/Mg^(2+)selectivity of the membrane.At an optimal sulfonation degree,the SP45 membrane forms a cross-linked structure,featuring contracted ionic clusters and discrete hydrophilic domains with limited interconnectivity.This unique microstructure imposes significantly higher energy barriers for the transmembrane transport of Mg^(2+),thereby endowing the SP45 membrane with exceptional perm-selectivity of 48.1 at a current density of 2 mA cm^(-2).Cycling stability tests reveal that the Li^(+)/Mg^(2+)selectivity degradation remains below 10%across multiple cycles in diverse mixed-salt systems.In practical brine ion distillation tests,we achieved a separation factor of exceeding 60,000 between Li^(+)and Mg^(2+)utilizing a 4-stage ion-distillation device equipped with the prepared SP45 membranes.This work provides fundamental insights into ion transport regulation through molecular-level acid-base pairs engineering,opening new avenues for advanced ion-selective separation membranes.展开更多
Solid state compounds of general formula Sr（Diclof）2 ·5.7H2O and Ba（Diclof）2·4.8H2O were obtained. Thermo- gravimetry （TG）, differential scanning calorimetry （DSC）, X-ray diffraction powder patterns ...Solid state compounds of general formula Sr（Diclof）2 ·5.7H2O and Ba（Diclof）2·4.8H2O were obtained. Thermo- gravimetry （TG）, differential scanning calorimetry （DSC）, X-ray diffraction powder patterns and microscopy analysis were used to characterize these compounds. Details concerning the dehydration and thermal decomposition as well as data of kinetic parameters have been described here. The kinetic behaviors of these stages were evaluated from several heating rates with samples masses of 2 and 5 mg in open crucibles under a nitrogen atmosphere. The results of the present study improve the knowledge on these compounds including their dehydration and thermal stability. The obtained data depend on the mass of the sample which results in two kinetic behavior patterns.展开更多
基金financially supported by the National Natural Science Foundation of China (No.U22B2094)。
文摘The mass application of Hall thrusters poses the need for a diagnostic method of ionization mechanism in the discharge channel to boost the iteration and optimization of thruster design.This work presents an Optical Emission Spectroscopy (OES) method for diagnostics of the contribution of different ionization mechanisms and the flux of ions in different valences in the discharge channel of a Hall thruster.The emission spectra in the discharge channel are analyzed by jointly utilizing a collisional-radiative model,an ionization-excitation model,and a flux-conservation model.It is found that the intensities of some spectral lines can be converted into the reaction rates of collision processes,e.g.,electron-induced excitation and ionization processes.The latter can further be used to determine the evolutions of particle fluxes by utilizing the conservation law of matter.The novel method is demonstrated on a kilo-watt Hall thruster.The evolutions of several parameters are determined using this method along the discharge channel,including the ionization rates of different mechanisms,particle fluxes,particle densities,and particle velocities.This novel method can be further developed by being jointly utilized with spectral imaging and tomography techniques,enabling diagnostics of multi-dimensional distributions of the above-mentioned parameters in the discharge channel and near-field plume.
基金supported by the National Natural Science Foundation of China(Grant Nos.:32271381,32471378 and 81971760)the Science and Technology Innovation Commission of Shenzhen(Grant No.:JCYJ20220530145601004)+4 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.:2024A1515010311)Dalian Medical Science Research Project(Grant NO.:2111038)State Key R&D Program(Grant NO.:2020JH2/10300093)Liaoning Provincial Department of Education Key Research Project(Grant NO.:LJKZZ20220148)Liaoning Provincial Health Commission,"Xingliao Plan of Excellence"Medical Masters Program(Grant NO.:YXMJ-QN-21).
文摘The divalent metal cations promote new bone formation through modulation of sensory and sympathetic nervous systems(SNS)activities.In addition,acetylcholine(Ach),as a chief neurotransmitter released by the parasympathetic nervous system(PNS),also affects bone remodeling,so it is of worth to investigate if the divalent cations influence PNS activity.Of note,these cations are key co-enzymes modulating glucose metabolism.Aerobic glycolysis rather than oxidative phosphorylation favors osteogenesis of mesenchymal stem cells(MSCs),so it is of interest to study the effects of these cations on glucose metabolic pathway.Prior to biological function assessment,the tolerance limits of the divalent metal cations(Mg^(2+),Zn^(2+),and Ca^(2+))and their combinations were profiled.In terms of direct effects,these divalent cations potentially enhanced migration and adhesion capability of MSCs through upregulating Tgf-β1 and Integrin-β1 levels.Interestingly,the divalent cations alone did not influence osteogenesis and aerobic glycolysis of undifferentiated MSCs.However,once the osteogenic differentiation of MSCs was initiated by neurotransmitters or osteogenic differentiation medium,the osteogenesis of MSCs could be significantly promoted by the divalent cations,which was accompanied by the improved aerobic glycolysis.In terms of indirect effects,the divalent cations significantly upregulated levels of sensory nerve derived CGRP,PNS produced choline acetyltransferase and type H vessels,while significantly tuned down sympathetic activity in the defect zone in rats,thereby contributing to significantly increased bone formation relative to the control group.Together,the divalent cations favor bone regeneration via modulation of sensory-autonomic nervous systems and promotion of aerobic glycolysis-driven osteogenesis of MSCs after osteogenic initiation by neurotransmitters.
文摘The fluorescent characteristic and emission spectra of Eu^(2+) in the cubic structure Ca_8Zn(SiO_4)_4Cl_2 with three kinds of cation sites is reported.The influence of temperature,Eu^(2+) concentra- tion and excitation conditions on fluorescent properties of Eu^(2+) are studied at 77 and 298 K.The coordination number of Eu^(2+) at different sites is obtained.The green and red emission bands arise from Eu_(2+) ions locating on eight- and six- coordinated inequivalent sites respectively.
基金Acknowledgements This work was partly supported by grants from the State Key Joint Laboratory of Environment Simulation and Pollution Control （10K04ESPCT）, the National Natural Science Foundation of China （Grant Nos. 51039007 and 51278500）, the program of Guangzhou Science ＆ Technology Department （No. 2012J4300115）, National Key Scientific Instrument and Equipment Development Project （No. 2012YQ0301110 803）, the Fundamental Research Funds for the Central Universities （131gpy55） and the innovative doctorial program of Sun Yat-sen University.
文摘Microbial desalination cell （MDC） is a promis- ing technology to desalinate water and generate electrical power simultaneously. The objectives of this study were to investigate the desalination performance of monovalent and divalent cations in the MDC, and discuss the effect of ion characteristics, ion concentrations, and electrical characteristics. Mixed salt solutions of NaC1, MgC12, KC1, and CaC12 with the same concentration were used in the desalination chamber to study removal of cations. Results showed that in the mixed salt solutions, the electrodialysis desalination rates of cations were： Ca2＋ 〉 Mg2＋ 〉 Na＋ 〉 K＋. Higher ionic charges and smaller hydrated ionic radii resulted in higher desalination rates of the cations, in which the ionic charge was more important than the hydrated ionic radius. Mixed solutions of NaC1 and MgC12 with different concentrations were used in the desalination chamber to study the effect of ion concentra- tions. Results showed that when ion concentrations ofNa＋ were one-fifth to five times of Mg2~, ion concentration influenced the dialysis more profoundly than electrodia- lysis. With the current densities below a certain value, charge transfer efficiencies became very low and the dialysis was the main process responsible for the desalination. And the phosphate transfer from the anode chamber and potassium transfer from the cathode chamber could balance 1%-3% of the charge transfer in the MDC.
基金supported by the Qingdao National La-boratory for Marine Science and Technology(No.QNLM 2016ORP0307)the National Key Research and Develop-ment Program of China(No.YFD0900504)+1 种基金the National Basic Research Program of China(No.2012CB114405)the Taishan Scholar Program of Shandong Province.
文摘Phenoloxidases(POs)are a group of copper proteins including tyrosinase,catecholase and laccase,which play crucial roles in the innate immune response of mollusks.In this research,POs were studied in cultured mollusk species,including scallop Chla-mys farreri,abalone Haliotis discus hannai and clam Scapharca subcrenata.The POs were isolated from hemocytes using linear-gradient native-PAGE combined with catechol staining.The PO activities and their characters were investigated.The molecular mass of PO in C.farreri was 576 kDa,and it was 228 kDa in H.discus hannai.In S.subcrenata,four POs were detected and their mole-cular masses were 391 kDa,206 kDa,174 kDa and<67 kDa,which were named as 391-PO,206-PO,174-PO and s-PO,respectively.Ki-netic analyses indicated that all of the POs,except for 391-PO had higher affinity to L-DOPA and catechol than to hydroquinone and dopamine.However,all of the POs failed to oxidize tyrosine.The effects of divalent metal ions on POs’activities were assayed,in-cluding Fe^(2+),Mg^(2+),Zn^(2+),Mn^(2+),Cu^(2+)and Ca^(2+)from FeCl_(2),MgSO_(4),ZnSO_(4),MnCl_(2),CuSO_(4)and CaCl_(2).The POs were inhibited by Fe^(2+)at all determined concentrations.Additionally,the inhibition assay showed that all of the POs were inhibited by cysteine,ascorbic acid,sodium sulfite,citric acid,ethylenediaminetetraacetic acid disodium(EDTA)and sodium diethyldithiocarbamate(DETC).The inhibition effects of critric acid and EDTA are dose-dependent.H.discus hannai PO and 391-PO were slightly inhibited by sodium azide,and H.discus hannai PO,391-PO and 174-PO were slightly inhibited by thiourea.In conclusion,the POs in the three cultured mollusks are copper-containing laccase-type phenoloxidases with similar biochemical characteristics even though their molecular masses are different.
文摘WTFZ] The interaction of adenosine triphosphate with divalent metal ions is important in biochemical functions. The effects of pH and metal ions Mg 2+ , Ca 2+ , Zn 2+ , Mn 2+ , and Co 2+ on the chemical shift of the phosphate group of ATP have been studied using Nuclear Magnetic Resonance. The chemical shift of the β-phosphate of ATP is the most sensitive to pH. Ca 2+ and Mg 2+ bind with the α- and β-phosphate groups of ATP. Zn 2+ binds to the adenosine ring hydrogen as well as to phosphate. The paramagnetic ions Mn 2+ and Co 2+ do not cause chemical shifts of the phosphate or proton peak. Mn 2+ and Co 2+ broaden the resonance peak only.[
基金supported by the National Key Research and Development Program of China(2022YFB3805100)National Natural Science Foundation of China(22222812 and 22178330).
文摘Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of acid-base pairs within a polybenzimidazole matrix through controlled sulfonation.By leveraging these intermolecular interactions,we enhance the Li^(+)/Mg^(2+)selectivity of the membrane.At an optimal sulfonation degree,the SP45 membrane forms a cross-linked structure,featuring contracted ionic clusters and discrete hydrophilic domains with limited interconnectivity.This unique microstructure imposes significantly higher energy barriers for the transmembrane transport of Mg^(2+),thereby endowing the SP45 membrane with exceptional perm-selectivity of 48.1 at a current density of 2 mA cm^(-2).Cycling stability tests reveal that the Li^(+)/Mg^(2+)selectivity degradation remains below 10%across multiple cycles in diverse mixed-salt systems.In practical brine ion distillation tests,we achieved a separation factor of exceeding 60,000 between Li^(+)and Mg^(2+)utilizing a 4-stage ion-distillation device equipped with the prepared SP45 membranes.This work provides fundamental insights into ion transport regulation through molecular-level acid-base pairs engineering,opening new avenues for advanced ion-selective separation membranes.
文摘Solid state compounds of general formula Sr（Diclof）2 ·5.7H2O and Ba（Diclof）2·4.8H2O were obtained. Thermo- gravimetry （TG）, differential scanning calorimetry （DSC）, X-ray diffraction powder patterns and microscopy analysis were used to characterize these compounds. Details concerning the dehydration and thermal decomposition as well as data of kinetic parameters have been described here. The kinetic behaviors of these stages were evaluated from several heating rates with samples masses of 2 and 5 mg in open crucibles under a nitrogen atmosphere. The results of the present study improve the knowledge on these compounds including their dehydration and thermal stability. The obtained data depend on the mass of the sample which results in two kinetic behavior patterns.
