Consider a generalized model of the facilitated exclusion process, which is a onedimensional exclusion process with a dynamical constraint that prevents the particle at site x from jumping to x+1 (or x-1) if the sites...Consider a generalized model of the facilitated exclusion process, which is a onedimensional exclusion process with a dynamical constraint that prevents the particle at site x from jumping to x+1 (or x-1) if the sites x-1, x-2 (or x+1, x+2) are empty. It is nongradient and lacks invariant measures of product form. The purpose of this paper is to identify the invariant measures and to show that they satisfy both exponential decay of correlations and equivalence of ensembles. These properties will play a pivotal role in deriving the hydrodynamic limit.展开更多
Objective To evaluate short time effects of primary percutaneous coronary intervention (pPCI) and rtPA thrombolysis+PCI (rtPA+PCI) on myocardial viability and ventricular systolic synchrony in AMI patients.Methods Eig...Objective To evaluate short time effects of primary percutaneous coronary intervention (pPCI) and rtPA thrombolysis+PCI (rtPA+PCI) on myocardial viability and ventricular systolic synchrony in AMI patients.Methods Eighty seven patients with first AMI were divided into two groups: group A ( n =42), pPCI group, the patients underwent PCI within 6h after onset of AMI; group B ( n =45), rtPA+PCI group, the patients underwent PCI after thrombolysis within 6h after onset of AMI; Myocardial viability was measured by 99m Tc MIBI SPECT. While, the parameters of cardiac function LVEF and ventricular systolic synchrony LVPS were measured by 99m Tc gated cardiac blood pool image on the first and the fourth weekend. Results (1) The peak CK MB was significantly lower in group A than that in group B( P <0.01 ). (2) Myocardial infarction area (MIA) was decreased and radioactivity counts in MIA was significantly increased in group A and B on the 4th weekend compared with that on the first weekend ( P <0.01 ), but there were no significant difference between group A and group B. (3) LVEF, LVPS were no significant difference between group A and group B.Conclusions (1)pPCI in acute myocardial infartion can limit infarct area, maintain ventricular systolic synchrony and improve ventricular function; (2) but, in those hospitals that there were no any condition for PCI, they should transfer the patients to central hospital for PCI after thrombolysis at the first time. It is beneficial to improve myocardial viability and ventricular systolic synchrony of AMI patients in short time.展开更多
Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transp...Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.展开更多
CO2 separation performance in facilitated transport membranes has been reported depended not only on the CO2 carrier properties but also to a great extent on the polymeric matrix regarding the capacity of retaining wa...CO2 separation performance in facilitated transport membranes has been reported depended not only on the CO2 carrier properties but also to a great extent on the polymeric matrix regarding the capacity of retaining water and carriers as well as the processability for coating defect-free ultra-thin films. In this study, the blends of hydrophilic polymers polyvinyl pyrrolidone(PVP) and polyvinyl alcohol(PVA) were studied to find an optimal polymer matrix to host carriers in facilitated transport membranes for enhanced CO2 separation. It is found out that the optimized blend is 50/50 PVA/PVP by weight, which shows a significant increase in the water uptake(from 63 to 84%) at equilibrium state compared to the neat PVA. Polyethyleneimine(PEI) was employed to provide sample carriers to evaluate the synergistic effect of PVA and PVP on the CO2 separation performance. A thin film composite(TFC) membrane of the optimized blend(50/50 PVA/PVP with 50 wt% PEI) was fabricated on polysulfone(PSf) porous support. The fabrication of the TFC membranes is simple and low cost, and CO2 permeance of the optimized blend membrane is nearly doubled with the CO2/N2 selectivity remained unchanged, showing great potential for industrial applications of the resulted membranes.展开更多
Glass micropipettes with silanized inner walls can be filled with an organic solvent for voltammetric measurements in an aqueous solution. This arrangement was employed to investigate systematically the mechanism of f...Glass micropipettes with silanized inner walls can be filled with an organic solvent for voltammetric measurements in an aqueous solution. This arrangement was employed to investigate systematically the mechanism of facilitated potassium ion transfer by an ionophore dibenzo 18 crown 6(DB18C6) across a micro water/1,2 dichloroethane(W/DCE) interface supported at the tip of a silanized micropipette. Our experimental results verify that this facilitated ion transfer across the liquid/liquid interface did occur by an interfacial complexation dissociation process(TIC TID mechanism). The ratio of the diffusion coefficient of DB18C6 to that of its complexed ion in the DCE phase was calculated to be 1.74±0.07.展开更多
1 INTRODUCTIONMany attempts to develop semipermeable membranes for gas separation have beendone over the past twenty years [1,2].However,it is still difficult to prepare apolymer film which makes certain gas separatio...1 INTRODUCTIONMany attempts to develop semipermeable membranes for gas separation have beendone over the past twenty years [1,2].However,it is still difficult to prepare apolymer film which makes certain gas separation processed within range of being econ-omically and technically feasible,since most polymeric materials are relativelyimpermeable to gases.Facilitated transport concept which was first proposed展开更多
The ionic liquid(IL) 1-butyl-3-methylimidazolium tetrafluoroborate treated with radiofrequency plasma is proposed for functionalization and immobilization on polyethersulfone supports to form supported ionic liquid me...The ionic liquid(IL) 1-butyl-3-methylimidazolium tetrafluoroborate treated with radiofrequency plasma is proposed for functionalization and immobilization on polyethersulfone supports to form supported ionic liquid membranes for CO_(2) separation.The effects of treatment time and transmembrane pressure difference on CO_(2) permeance were evaluated.The best gas permeation performance was obtained with a treatment time of 10 min and the transmembrane pressure difference was 0.25 MPa.Characterization of the materials by Fourier transform infrared spectroscopy,x-ray photoelectron spectroscopy and nuclear magnetic resonance spectroscopy demonstrates that the IL is grafted with carboxyl groups and deprotonated through plasma treatment.A preliminary mechanism for the plasma treatment and facilitated transport of CO_(2)has been proposed on this basis.展开更多
When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytri...When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytrichiodes as a model species,we aimed to assess the sex-specific facilitation intensity of cushion plant by measuring the beneficiary cover ratio,and to assess the potential costs in cushion reproductive functions by measuring the flower and fruit cover ratios.The total beneficiary cover ratio was similar between females and hermaphrodites.Females produced much less flowers but more fruits than hermaphrodites.These results suggested that females and hermaphrodites possess similar facilitation intensity,and female cushion A.polytrichoides may allocate more resources saved from pollen production to seed production,while hermaphrodites possibly allocate more resources to pollen production hence reducing seed production.The surface areas covered by beneficiaries produced less flowers and fruits than areas without beneficiaries.In addition,strong negative correlations between beneficiary cover and flower cover were detected for both females and hermaphrodites,but the correlation strength were similar for these two sex morphs.However,the correlation between beneficiary cover and fruit cover was only significantly negative for females,suggesting that beneficiary plants negatively affect fruit reproduction of females while have neutral effects on hermaphrodites.All the results suggest that to facilitate other beneficiaries can induce reproductive costs on cushion A.polytrichoides,with females possibly suffering greater cost than hermaphrodites.Such differentiation in reproductive costs between sex morphs,in long-term perspective,may imply sex imbalance in population dynamics.展开更多
Prunus serotina and Robinia pseudoacacia are the most widespread invasive trees in Central Europe.In addition,according to climate models,decreased growth of many economically and ecologically important native trees w...Prunus serotina and Robinia pseudoacacia are the most widespread invasive trees in Central Europe.In addition,according to climate models,decreased growth of many economically and ecologically important native trees will likely be observed in the future.We aimed to assess the impact of these two neophytes,which differ in the biomass range and nitrogen-fixing abilities observed in Central European conditions,on the relative aboveground biomass increments of native oaks Qucrcus robur and Q.petraea and Scots pine Pinus sylvestris.We aimed to increase our understanding of the relationship between facilitation and competition between woody alien species and overstory native trees.We established 72 circular plots(0.05 ha)in two different forest habitat types and stands varying in age in western Poland.We chose plots with different abundances of the studied neophytes to determine how effects scaled along the quantitative invasion gradient.Furthermore,we collected growth cores of the studied native species,and we calculated aboveground biomass increments at the tree and stand levels.Then,we used generalized linear mixed-effects models to assess the impact of invasive species abundances on relative aboveground biomass increments of native tree species.We did not find a biologically or statistically significant impact of invasive R.pseudoacacia or P.serotina on the relative aboveground,biomass increments of native oaks and pines along the quantitative gradient of invader biomass or on the proportion of total stand biomass accounted for by invaders.The neophytes did not act as native tree growth stimulators but also did not compete with them for resources,which would escalate the negative impact of climate change on pines and oaks.The neophytes should not significantly modify the carbon sequestration capacity of the native species.Our work combines elements of the per capita effect of invasion with research on mixed forest management.展开更多
The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year...The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year-old girl were found gagged,raped,and murdered,often by slitting their throats,and some of their bodies were mutilated brutally,resembling the infamous‘‘Jack the Ripper’’killings that occurred in London more than one hundred years ago.Nine of these 11 murders took place展开更多
The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/l,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic volt-amm...The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/l,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic volt-ammetric measurements were performed in two limiting conditions: the bulk concentration of Na+ or K+ in the aqueous phase is much higher than that of DB15C5 in the organic phase (DB15C5 diffusion controlled process) and the reverse condition (metal ion diffusion controlled process). The mechanisms of the facilitated Na+ transfer by DB15C5 are both transfer by interfacial complexation (TIC) with 1:1 stoichiometry under these two conditions, and the corresponding association constants were determined at log β1 = 8.97±0.05 or log β1 = 8.63±0.03. However, the transfers of K+ facilitated by DB15C5 show different behavior. In the former case it is a TIC process and its stoichiometry is 1:2, whereas in the latter case two peaks during the forward scan were observed, the first of which was展开更多
Selective separation of CO_(2) and H_(2)S from CH_(4) is of importance to the natural gas upgrading because of its cor-rosivity. As is well known, amine group can recognize reversibly CO_(2) and H_(2)S with a moderate...Selective separation of CO_(2) and H_(2)S from CH_(4) is of importance to the natural gas upgrading because of its cor-rosivity. As is well known, amine group can recognize reversibly CO_(2) and H_(2)S with a moderate interaction. Withthis in mind, this work prepared a series of amine-functionalized supported-protic-ionic-liquid membranes(SPILMs) for the selective separation of CO_(2) and H_(2)S from CH_(4) . For comparison, aprotic ionic liquid membranewas also prepared for natural gas sweetening. The effect of temperature and transmembrane pressure differenceon the permeability of single gas and ideal selectivity of CO_(2)/CH_(4) and H_(2)S/CO_(2) were studied. Facilitated transportmechanism was studied by NMR spectra. The permeability of CO_(2) in primary amine functionalized [DMPDAH][Tf_(2)N]-based membrane decreases with the increasing transmembrane pressure, indicating a typical feature offacilitated transport membrane. The permeability of CO_(2) and the ideal selective of CO_(2)/CH_(4) are as high as 2000 barrers and 53.2 at 313.2 K in [DMPDAH][Tf_(2)N] membrane, significantly higher than those in conventional ILsmembrane. It is anticipated that these amine-functionalized SPILMs can provide alternative insight for the se-lective separation of CO_(2) and H_(2)S from CH_(4) .展开更多
Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,...Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,the size and age of shrubs from 26 Salix shrubline populations along a 900-km latitudinal gradient(30°-38°N)were measured and mapped across the eastern Tibetan Plateau.Point pattern analyses were used to quantify the spatial distribution patterns of juveniles and adults,and to assess spatial associations between them.Mean intensity of univariate and bivariate spatial patterns was related to biotic and abiotic variables.Bivariate mark correlation functions with a quantitative mark(shrub height,basal stem diameter,crown width)were also employed to investigate the spatial relationships between shrub traits of juveniles and adults.Structural equation models were used to explore the relationships among conspecific interactions,patterns,shrub traits and recruitment dynamics under climate change.Most shrublines showed clustered patterns,suggesting the existence of conspecific facilitation.Clustered patterns of juveniles and conspecific interactions(potentially facilitation)tended to intensify with increasing soil moisture stress.Summer warming before 2010 triggered positive effects on population interactions and spatial patterns via increased shrub recruitment.However,summer warming after2010 triggered negative effects on interactions through reduced shrub recruitment.Therefore,shrub recruitment shifts under rapid climate change could impact spatial patterns,alter conspecific interactions and modify the direction and degree of shrublines responses to climate.These changes would have profound implications for the stability of alpine woody ecosystems.展开更多
The challenge in the clinical treatment of Parkinson's disease lies in the lack of disease-modifying therapies that can halt or slow down the progression. Peptide drugs, such as exenatide (Exe), with potential dis...The challenge in the clinical treatment of Parkinson's disease lies in the lack of disease-modifying therapies that can halt or slow down the progression. Peptide drugs, such as exenatide (Exe), with potential disease-modifying efficacy, have difficulty in crossing the blood-brain barrier (BBB) due to their large molecular weight. Herein, we fabricate multi-functionalized lipid nanoparticles (LNP) Lpc-BoSA/CSO with BBB targeting, permeability-increasing and responsive release functions. Borneol is chemically bonded with stearic acid and, as one of the components of Lpc-BoSA/CSO, is used to increase BBB permeability. Immunofluorescence results of brain tissue of 15-month-old C57BL/6 mice show that Lpc-BoSA/CSO disperses across the BBB into brain parenchyma, and the amount is 4.21 times greater than that of conventional LNP. Motor symptoms of mice in Lpc-BoSA/CSO-Exe group are significantly improved, and the content of dopamine is 1.85 times (substantia nigra compacta) and 1.49 times (striatum) that of PD mice. α-Synuclein expression and Lewy bodies deposition are reduced to 51.85% and 44.72% of PD mice, respectively. Immunohistochemical mechanism studies show AKT expression in Lpc-BoSA/CSO-Exe is 4.23 times that of PD mice and GSK-3β expression is reduced to 18.41%. Lpc-BoSA/CSO-Exe could reduce the production of α-synuclein and Lewy bodies through AKT/GSK-3β pathway, and effectively prevent the progressive deterioration of Parkinson's disease. In summary, Lpc-BoSA/CSO-Exe increases the entry of exenatide into brain and promotes its clinical application for Parkinson's disease therapy.展开更多
The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment;however,the molecular mechanisms underlying the formation and function of the bloo...The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment;however,the molecular mechanisms underlying the formation and function of the blood-brain barrier remain poorly understood.The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood-brain barrier function.It plays a critical role in promoting and maintaining the formation and functional stability of the blood-brain barrier,in addition to the transport of lipids,such as docosahexaenoic acid,across the blood-brain barrier.Furthermore,an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood-brain barrier dysfunction in a variety of neurological diseases;however,little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood-brain barrier.This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood-brain barrier,including their basic structures and functions,cross-linking between major facilitator superfamily domain containing 2A and the blood-brain barrier,and the in-depth studies on lipid transport and the regulation of blood-brain barrier permeability.This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood-brain barrier and the research progress to date.This will not only help to elucidate the pathogenesis of neurological diseases,improve the accuracy of laboratory diagnosis,and optimize clinical treatment strategies,but it may also play an important role in prognostic monitoring.In addition,the effects of major facilitator superfamily domain containing 2A on blood-brain barrier leakage in various diseases and the research progress on cross-blood-brain barrier drug delivery are summarized.This review may contribute to the development of new approaches for the treatment of neurological diseases.展开更多
With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important forc...With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important force in the global economy, and the progress of the BRICS countries' trade facilitation level has an important impact on the global trade environment. This paper conducts an in-depth study of the dynamic changes in BRICS trade facilitation from 2013 to 2022, and uses an extended gravity model to analyze the specific impact of this change on China's exports using cross-border e-commerce. The results show that although the BRICS countries have made some progress in trade facilitation, the overall level still needs to be improved, and there are obvious differences among member countries. However, the improvement of trade facilitation among BRICS countries has undoubtedly brought significant positive effects to China's exports using cross-border e-commerce.展开更多
Lawmakers call for stepping up hydrogen power production to facilitate China’s clean and low-carbon energy transformation and create a new engine of growth.
Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically...Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, lie, Phe, Trp, Met, Ala, Gly, Cys, Gin (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (β0), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively. The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attributed to the vicinal effect arising from steric hindrance introduced by their side group and the steric bulk effect by lipophilic stabilization. Moreover, the association constants and the standard rate constants for different amino acids showed good correlations with their hydrophobicity (π), except Gly and Met, which inferred that the selectivity of such heterogeneous complex reaction for different amino acids with DB18C6, was not only affected by discrimination in binding these ions to the crown ether macro-cycle, but also significantly modified by the ion transfer Gibbs energy which was closely related to the structure of the transferred ions, protonated amino acids.展开更多
This study evaluated the impact of Ghana’s Integrated Customs Management System (ICUMS), implemented within the National Single Window initiative, on the efficiency of issuing Delivery Orders (DO) at Tema Port. Filli...This study evaluated the impact of Ghana’s Integrated Customs Management System (ICUMS), implemented within the National Single Window initiative, on the efficiency of issuing Delivery Orders (DO) at Tema Port. Filling a gap in the existing literature, the research employed a quantitative approach to assess a specific time-related aspect of the cargo clearance process. Employing an Independent t-test on a dataset spanning 2026 Delivery Orders (924 pre-ICUMS and 1102 post-ICUMS) from July 2020 to July 2023, the study investigated ICUMS’s effectiveness in reducing DO issuance time. Results indicate a noteworthy decrease in average DO issuance time, from 11 days pre-implementation to approximately 9 days post-implementation, a reduction validated by statistical analysis through the independent t-test. In light of these findings, the study recommends ongoing refinement of the implementation, reinforcement of trade facilitation measures, and the adoption of best practices from successful global ports. Continuous stakeholder training and regular assessments of ICUMS performance are also endorsed. The study’s implications support the theoretical framework for Single Window systems and carry significant policy implications, emphasizing the need for collaborative efforts to streamline trade facilitation processes driven by Information Technology. Practically, the results serve as a management tool for stakeholders, highlighting areas for targeted interventions to reduce DO issuance times. Methodologically, this research contributes by applying robust statistical analysis to a specific component within the Time Release Study framework, offering a nuanced understanding of trade facilitation systems’ effectiveness in improving cargo clearance processes.展开更多
基金Supported in part by the National Natural Science Foundation of China(11731012, 11871425, 12271475)Fundamental Research Funds for Central Universities grant(2020XZZX002-03)。
文摘Consider a generalized model of the facilitated exclusion process, which is a onedimensional exclusion process with a dynamical constraint that prevents the particle at site x from jumping to x+1 (or x-1) if the sites x-1, x-2 (or x+1, x+2) are empty. It is nongradient and lacks invariant measures of product form. The purpose of this paper is to identify the invariant measures and to show that they satisfy both exponential decay of correlations and equivalence of ensembles. These properties will play a pivotal role in deriving the hydrodynamic limit.
文摘Objective To evaluate short time effects of primary percutaneous coronary intervention (pPCI) and rtPA thrombolysis+PCI (rtPA+PCI) on myocardial viability and ventricular systolic synchrony in AMI patients.Methods Eighty seven patients with first AMI were divided into two groups: group A ( n =42), pPCI group, the patients underwent PCI within 6h after onset of AMI; group B ( n =45), rtPA+PCI group, the patients underwent PCI after thrombolysis within 6h after onset of AMI; Myocardial viability was measured by 99m Tc MIBI SPECT. While, the parameters of cardiac function LVEF and ventricular systolic synchrony LVPS were measured by 99m Tc gated cardiac blood pool image on the first and the fourth weekend. Results (1) The peak CK MB was significantly lower in group A than that in group B( P <0.01 ). (2) Myocardial infarction area (MIA) was decreased and radioactivity counts in MIA was significantly increased in group A and B on the 4th weekend compared with that on the first weekend ( P <0.01 ), but there were no significant difference between group A and group B. (3) LVEF, LVPS were no significant difference between group A and group B.Conclusions (1)pPCI in acute myocardial infartion can limit infarct area, maintain ventricular systolic synchrony and improve ventricular function; (2) but, in those hospitals that there were no any condition for PCI, they should transfer the patients to central hospital for PCI after thrombolysis at the first time. It is beneficial to improve myocardial viability and ventricular systolic synchrony of AMI patients in short time.
文摘Carbon dioxide(CO_(2))capture by gas-separation membranes has become increasingly attractive due to its high energy efficiency,relatively low cost,and environmental impact.Polyvinylamine(PVAm)-based facilitated transport(FT)membranes were developed in the last decade for CO_(2) capture.This work discusses the challenges of applying PVAm-based FT membranes from materials to processes for postcombustion CO_(2) capture in power plants and cement factories.Experiences learned from a pilot demonstration system can be used to guide the design of other membranes for CO_(2) capture.The importance of module and process design is emphasized in the achievement of a high-performance membrane system.Moreover,the results from process simulation and cost estimation indicate that a three-stage membrane system is feasible for achieving a high CO_(2) purity of 95 vol%.The specific CO_(2) capture cost was found to significantly depend on the required CO_(2) capture ratio,and a moderate CO_(2) capture ratio of 50%presented a cost of 63.7USD per tonne CO_(2) captured.Thus,FT membrane systems were found to be more competitive for partial CO_(2) capture.
基金the Norwegian Research Council for the financial support to this work through the Nano2021 program (project number 239172)
文摘CO2 separation performance in facilitated transport membranes has been reported depended not only on the CO2 carrier properties but also to a great extent on the polymeric matrix regarding the capacity of retaining water and carriers as well as the processability for coating defect-free ultra-thin films. In this study, the blends of hydrophilic polymers polyvinyl pyrrolidone(PVP) and polyvinyl alcohol(PVA) were studied to find an optimal polymer matrix to host carriers in facilitated transport membranes for enhanced CO2 separation. It is found out that the optimized blend is 50/50 PVA/PVP by weight, which shows a significant increase in the water uptake(from 63 to 84%) at equilibrium state compared to the neat PVA. Polyethyleneimine(PEI) was employed to provide sample carriers to evaluate the synergistic effect of PVA and PVP on the CO2 separation performance. A thin film composite(TFC) membrane of the optimized blend(50/50 PVA/PVP with 50 wt% PEI) was fabricated on polysulfone(PSf) porous support. The fabrication of the TFC membranes is simple and low cost, and CO2 permeance of the optimized blend membrane is nearly doubled with the CO2/N2 selectivity remained unchanged, showing great potential for industrial applications of the resulted membranes.
基金Supported by Chinese Academ y of Sciences(CAS) National Natural Science Foundation of China(No. 2 982 5 111) andthe Third World Academ y of Science(TWAS) and the State Key L aboratory of Electroanalytical Chem istry of the CAS.
文摘Glass micropipettes with silanized inner walls can be filled with an organic solvent for voltammetric measurements in an aqueous solution. This arrangement was employed to investigate systematically the mechanism of facilitated potassium ion transfer by an ionophore dibenzo 18 crown 6(DB18C6) across a micro water/1,2 dichloroethane(W/DCE) interface supported at the tip of a silanized micropipette. Our experimental results verify that this facilitated ion transfer across the liquid/liquid interface did occur by an interfacial complexation dissociation process(TIC TID mechanism). The ratio of the diffusion coefficient of DB18C6 to that of its complexed ion in the DCE phase was calculated to be 1.74±0.07.
文摘1 INTRODUCTIONMany attempts to develop semipermeable membranes for gas separation have beendone over the past twenty years [1,2].However,it is still difficult to prepare apolymer film which makes certain gas separation processed within range of being econ-omically and technically feasible,since most polymeric materials are relativelyimpermeable to gases.Facilitated transport concept which was first proposed
基金supported by the National Key R&D Program of China ‘Intergovernmental International Scientific and Technological Innovation Cooperation’ (No. 2019YFE0122100)。
文摘The ionic liquid(IL) 1-butyl-3-methylimidazolium tetrafluoroborate treated with radiofrequency plasma is proposed for functionalization and immobilization on polyethersulfone supports to form supported ionic liquid membranes for CO_(2) separation.The effects of treatment time and transmembrane pressure difference on CO_(2) permeance were evaluated.The best gas permeation performance was obtained with a treatment time of 10 min and the transmembrane pressure difference was 0.25 MPa.Characterization of the materials by Fourier transform infrared spectroscopy,x-ray photoelectron spectroscopy and nuclear magnetic resonance spectroscopy demonstrates that the IL is grafted with carboxyl groups and deprotonated through plasma treatment.A preliminary mechanism for the plasma treatment and facilitated transport of CO_(2)has been proposed on this basis.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0502 to H.S.)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20050203 to H.S.)+3 种基金the Yunnan Applied Basic Research Project(202001AT070060 to J.G.C.)the National Natural Science Foundation of China(31271552 to J.G.C.)the CAS“Light of West China”Program(J.G.C.)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(202205AC160053 to J.G.C.)。
文摘When benefiting other beneficiaries,cushion plants may reciprocally receive feedback effects.The feedback effects on different sex morphs,however,remains unclear.In this study,taking the gynodioecious Arenaria polytrichiodes as a model species,we aimed to assess the sex-specific facilitation intensity of cushion plant by measuring the beneficiary cover ratio,and to assess the potential costs in cushion reproductive functions by measuring the flower and fruit cover ratios.The total beneficiary cover ratio was similar between females and hermaphrodites.Females produced much less flowers but more fruits than hermaphrodites.These results suggested that females and hermaphrodites possess similar facilitation intensity,and female cushion A.polytrichoides may allocate more resources saved from pollen production to seed production,while hermaphrodites possibly allocate more resources to pollen production hence reducing seed production.The surface areas covered by beneficiaries produced less flowers and fruits than areas without beneficiaries.In addition,strong negative correlations between beneficiary cover and flower cover were detected for both females and hermaphrodites,but the correlation strength were similar for these two sex morphs.However,the correlation between beneficiary cover and fruit cover was only significantly negative for females,suggesting that beneficiary plants negatively affect fruit reproduction of females while have neutral effects on hermaphrodites.All the results suggest that to facilitate other beneficiaries can induce reproductive costs on cushion A.polytrichoides,with females possibly suffering greater cost than hermaphrodites.Such differentiation in reproductive costs between sex morphs,in long-term perspective,may imply sex imbalance in population dynamics.
基金financed by the National Science Centre,Poland,under project No.2019/35/B/NZ8/01381 entitled"Impact of invasive tree species on ecosystem services:plant biodiversity,carbon and nitrogen cycling and climate regulation"by the Institute of Dendrology,Polish Academy of Sciences。
文摘Prunus serotina and Robinia pseudoacacia are the most widespread invasive trees in Central Europe.In addition,according to climate models,decreased growth of many economically and ecologically important native trees will likely be observed in the future.We aimed to assess the impact of these two neophytes,which differ in the biomass range and nitrogen-fixing abilities observed in Central European conditions,on the relative aboveground biomass increments of native oaks Qucrcus robur and Q.petraea and Scots pine Pinus sylvestris.We aimed to increase our understanding of the relationship between facilitation and competition between woody alien species and overstory native trees.We established 72 circular plots(0.05 ha)in two different forest habitat types and stands varying in age in western Poland.We chose plots with different abundances of the studied neophytes to determine how effects scaled along the quantitative invasion gradient.Furthermore,we collected growth cores of the studied native species,and we calculated aboveground biomass increments at the tree and stand levels.Then,we used generalized linear mixed-effects models to assess the impact of invasive species abundances on relative aboveground biomass increments of native tree species.We did not find a biologically or statistically significant impact of invasive R.pseudoacacia or P.serotina on the relative aboveground,biomass increments of native oaks and pines along the quantitative gradient of invader biomass or on the proportion of total stand biomass accounted for by invaders.The neophytes did not act as native tree growth stimulators but also did not compete with them for resources,which would escalate the negative impact of climate change on pines and oaks.The neophytes should not significantly modify the carbon sequestration capacity of the native species.Our work combines elements of the per capita effect of invasion with research on mixed forest management.
基金supported by the National Natural Science Foundation of China (31671297, 81671874)NSFC for Excellent Young Scholar (31222030)+4 种基金MOE Scientific Research Project (113022A)Shanghai Shuguang Project (14SG05), Natural Science Foundation of Gansu Province (1308RJZA190)Scientific Research Project for Colleges of Gansu Province (2014A-085)Evidence Science, Technology and Application for Key Laboratory Foundation of Gansu Province (ZDSYS-Y20)Gansu Institute of Political Science and Law Foundation Project (GZF2011XQNLW45)
文摘The Baiyin serial murders,or called Gan-Meng 8.05 serial murders,has been considered to be the most infamous among the major criminal cases since 1949.Between May26,1988 and February 9,2002,11 women including an8-year-old girl were found gagged,raped,and murdered,often by slitting their throats,and some of their bodies were mutilated brutally,resembling the infamous‘‘Jack the Ripper’’killings that occurred in London more than one hundred years ago.Nine of these 11 murders took place
基金This work was supported by the Chinese Academy of Sciencesthe National Natural Science Foundation of China (Grant No. 29825111)the State Key Laboratory of Electroanalytical Chemistry.
文摘The transfer of sodium and potassium ions facilitated by dibenzo-15-crown-5 (DB15C5) has been studied at the micro-water/l,2-dichloroethane (water/DCE) interface supported at the tip of a micropipette. Cyclic volt-ammetric measurements were performed in two limiting conditions: the bulk concentration of Na+ or K+ in the aqueous phase is much higher than that of DB15C5 in the organic phase (DB15C5 diffusion controlled process) and the reverse condition (metal ion diffusion controlled process). The mechanisms of the facilitated Na+ transfer by DB15C5 are both transfer by interfacial complexation (TIC) with 1:1 stoichiometry under these two conditions, and the corresponding association constants were determined at log β1 = 8.97±0.05 or log β1 = 8.63±0.03. However, the transfers of K+ facilitated by DB15C5 show different behavior. In the former case it is a TIC process and its stoichiometry is 1:2, whereas in the latter case two peaks during the forward scan were observed, the first of which was
基金This work was sponsored by the Natural Science Foundation of Jiangsu Province(BK20190310)China Postdoctoral Science Foundation(2021M691515)+1 种基金the Postdoctoral Science Foundation of Jiangsu Province(2021K211B)the National Natural Science Foundation of China(Nos.22078145 and 21878141)。
文摘Selective separation of CO_(2) and H_(2)S from CH_(4) is of importance to the natural gas upgrading because of its cor-rosivity. As is well known, amine group can recognize reversibly CO_(2) and H_(2)S with a moderate interaction. Withthis in mind, this work prepared a series of amine-functionalized supported-protic-ionic-liquid membranes(SPILMs) for the selective separation of CO_(2) and H_(2)S from CH_(4) . For comparison, aprotic ionic liquid membranewas also prepared for natural gas sweetening. The effect of temperature and transmembrane pressure differenceon the permeability of single gas and ideal selectivity of CO_(2)/CH_(4) and H_(2)S/CO_(2) were studied. Facilitated transportmechanism was studied by NMR spectra. The permeability of CO_(2) in primary amine functionalized [DMPDAH][Tf_(2)N]-based membrane decreases with the increasing transmembrane pressure, indicating a typical feature offacilitated transport membrane. The permeability of CO_(2) and the ideal selective of CO_(2)/CH_(4) are as high as 2000 barrers and 53.2 at 313.2 K in [DMPDAH][Tf_(2)N] membrane, significantly higher than those in conventional ILsmembrane. It is anticipated that these amine-functionalized SPILMs can provide alternative insight for the se-lective separation of CO_(2) and H_(2)S from CH_(4) .
基金the National Natural Science Foundation of China(42271054)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0301)。
文摘Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,the size and age of shrubs from 26 Salix shrubline populations along a 900-km latitudinal gradient(30°-38°N)were measured and mapped across the eastern Tibetan Plateau.Point pattern analyses were used to quantify the spatial distribution patterns of juveniles and adults,and to assess spatial associations between them.Mean intensity of univariate and bivariate spatial patterns was related to biotic and abiotic variables.Bivariate mark correlation functions with a quantitative mark(shrub height,basal stem diameter,crown width)were also employed to investigate the spatial relationships between shrub traits of juveniles and adults.Structural equation models were used to explore the relationships among conspecific interactions,patterns,shrub traits and recruitment dynamics under climate change.Most shrublines showed clustered patterns,suggesting the existence of conspecific facilitation.Clustered patterns of juveniles and conspecific interactions(potentially facilitation)tended to intensify with increasing soil moisture stress.Summer warming before 2010 triggered positive effects on population interactions and spatial patterns via increased shrub recruitment.However,summer warming after2010 triggered negative effects on interactions through reduced shrub recruitment.Therefore,shrub recruitment shifts under rapid climate change could impact spatial patterns,alter conspecific interactions and modify the direction and degree of shrublines responses to climate.These changes would have profound implications for the stability of alpine woody ecosystems.
基金National Natural Science Foundation of China(grant nos.81973267)Natural Science Foundation of Zhejiang Province(grant nos.LD19H300001).
文摘The challenge in the clinical treatment of Parkinson's disease lies in the lack of disease-modifying therapies that can halt or slow down the progression. Peptide drugs, such as exenatide (Exe), with potential disease-modifying efficacy, have difficulty in crossing the blood-brain barrier (BBB) due to their large molecular weight. Herein, we fabricate multi-functionalized lipid nanoparticles (LNP) Lpc-BoSA/CSO with BBB targeting, permeability-increasing and responsive release functions. Borneol is chemically bonded with stearic acid and, as one of the components of Lpc-BoSA/CSO, is used to increase BBB permeability. Immunofluorescence results of brain tissue of 15-month-old C57BL/6 mice show that Lpc-BoSA/CSO disperses across the BBB into brain parenchyma, and the amount is 4.21 times greater than that of conventional LNP. Motor symptoms of mice in Lpc-BoSA/CSO-Exe group are significantly improved, and the content of dopamine is 1.85 times (substantia nigra compacta) and 1.49 times (striatum) that of PD mice. α-Synuclein expression and Lewy bodies deposition are reduced to 51.85% and 44.72% of PD mice, respectively. Immunohistochemical mechanism studies show AKT expression in Lpc-BoSA/CSO-Exe is 4.23 times that of PD mice and GSK-3β expression is reduced to 18.41%. Lpc-BoSA/CSO-Exe could reduce the production of α-synuclein and Lewy bodies through AKT/GSK-3β pathway, and effectively prevent the progressive deterioration of Parkinson's disease. In summary, Lpc-BoSA/CSO-Exe increases the entry of exenatide into brain and promotes its clinical application for Parkinson's disease therapy.
基金supported by the National Natural Science Foundation of China,No.82104412(to TD)Shaanxi Provincial Key R&D Program,No.2023-YBSF-165(to TD)+1 种基金the Natural Science Foundation of Shaanxi Department of Science and Technology,No.2018JM7022(to FM)Shaanxi Provincial Key Industry Chain Project,No.2021ZDLSF04-11(to PW)。
文摘The functional and structural integrity of the blood-brain barrier is crucial in maintaining homeostasis in the brain microenvironment;however,the molecular mechanisms underlying the formation and function of the blood-brain barrier remain poorly understood.The major facilitator superfamily domain containing 2A has been identified as a key regulator of blood-brain barrier function.It plays a critical role in promoting and maintaining the formation and functional stability of the blood-brain barrier,in addition to the transport of lipids,such as docosahexaenoic acid,across the blood-brain barrier.Furthermore,an increasing number of studies have suggested that major facilitator superfamily domain containing 2A is involved in the molecular mechanisms of blood-brain barrier dysfunction in a variety of neurological diseases;however,little is known regarding the mechanisms by which major facilitator superfamily domain containing 2A affects the blood-brain barrier.This paper provides a comprehensive and systematic review of the close relationship between major facilitator superfamily domain containing 2A proteins and the blood-brain barrier,including their basic structures and functions,cross-linking between major facilitator superfamily domain containing 2A and the blood-brain barrier,and the in-depth studies on lipid transport and the regulation of blood-brain barrier permeability.This comprehensive systematic review contributes to an in-depth understanding of the important role of major facilitator superfamily domain containing 2A proteins in maintaining the structure and function of the blood-brain barrier and the research progress to date.This will not only help to elucidate the pathogenesis of neurological diseases,improve the accuracy of laboratory diagnosis,and optimize clinical treatment strategies,but it may also play an important role in prognostic monitoring.In addition,the effects of major facilitator superfamily domain containing 2A on blood-brain barrier leakage in various diseases and the research progress on cross-blood-brain barrier drug delivery are summarized.This review may contribute to the development of new approaches for the treatment of neurological diseases.
基金Supported by Western Project of National Social Science Fund of China(23XJY013)Project of Social Science Foundation of Shaanxi Province(2022D032).
文摘With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important force in the global economy, and the progress of the BRICS countries' trade facilitation level has an important impact on the global trade environment. This paper conducts an in-depth study of the dynamic changes in BRICS trade facilitation from 2013 to 2022, and uses an extended gravity model to analyze the specific impact of this change on China's exports using cross-border e-commerce. The results show that although the BRICS countries have made some progress in trade facilitation, the overall level still needs to be improved, and there are obvious differences among member countries. However, the improvement of trade facilitation among BRICS countries has undoubtedly brought significant positive effects to China's exports using cross-border e-commerce.
文摘Lawmakers call for stepping up hydrogen power production to facilitate China’s clean and low-carbon energy transformation and create a new engine of growth.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20235010,20173058 and 2985111)the Special 985 Project of Peking University.
文摘Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, lie, Phe, Trp, Met, Ala, Gly, Cys, Gin (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (β0), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively. The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attributed to the vicinal effect arising from steric hindrance introduced by their side group and the steric bulk effect by lipophilic stabilization. Moreover, the association constants and the standard rate constants for different amino acids showed good correlations with their hydrophobicity (π), except Gly and Met, which inferred that the selectivity of such heterogeneous complex reaction for different amino acids with DB18C6, was not only affected by discrimination in binding these ions to the crown ether macro-cycle, but also significantly modified by the ion transfer Gibbs energy which was closely related to the structure of the transferred ions, protonated amino acids.
文摘This study evaluated the impact of Ghana’s Integrated Customs Management System (ICUMS), implemented within the National Single Window initiative, on the efficiency of issuing Delivery Orders (DO) at Tema Port. Filling a gap in the existing literature, the research employed a quantitative approach to assess a specific time-related aspect of the cargo clearance process. Employing an Independent t-test on a dataset spanning 2026 Delivery Orders (924 pre-ICUMS and 1102 post-ICUMS) from July 2020 to July 2023, the study investigated ICUMS’s effectiveness in reducing DO issuance time. Results indicate a noteworthy decrease in average DO issuance time, from 11 days pre-implementation to approximately 9 days post-implementation, a reduction validated by statistical analysis through the independent t-test. In light of these findings, the study recommends ongoing refinement of the implementation, reinforcement of trade facilitation measures, and the adoption of best practices from successful global ports. Continuous stakeholder training and regular assessments of ICUMS performance are also endorsed. The study’s implications support the theoretical framework for Single Window systems and carry significant policy implications, emphasizing the need for collaborative efforts to streamline trade facilitation processes driven by Information Technology. Practically, the results serve as a management tool for stakeholders, highlighting areas for targeted interventions to reduce DO issuance times. Methodologically, this research contributes by applying robust statistical analysis to a specific component within the Time Release Study framework, offering a nuanced understanding of trade facilitation systems’ effectiveness in improving cargo clearance processes.