Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carb...High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.展开更多
Accelerating the development of new quality productive forces(NQPF),with innovation at its core,has become essential for firm growth in the new era.Drawing on financial data from China's A-share listed companies s...Accelerating the development of new quality productive forces(NQPF),with innovation at its core,has become essential for firm growth in the new era.Drawing on financial data from China's A-share listed companies spanning the period 2010–2023,this study empirically investigates the impact of entrepreneurial spirit on firm-level NQPF.The results indicate that entrepreneurial spirit significantly promotes firm-level NQPF.Mechanism analysis indicates that entrepreneurial effort—underpinned by technological capital accumulation,effective incentive and constraint mechanisms,and a competitive market environment—plays a mediating role in this relationship.Further heterogeneity analysis reveals that,amid China's economic transition,the positive effects of entrepreneurial spirit are more pronounced in non-state-owned enterprises,high-tech firms,and newly established firms.Accordingly,systematic efforts should be pursued across the technological,organizational,and environmental(TOE)dimensions to optimize the cultivation of entrepreneurial spirit.In particular,greater emphasis should be placed on productive entrepreneurial spirit and the constructive role of entrepreneurial effort,so as to fully leverage their contribution to the advancement of firm-level NQPF.展开更多
The development of efficient photocatalysts for crucial organic transformation,such as aerobic oxidation,remains challenging.Although powdered porous materials offer abundant accessible active sites,their application ...The development of efficient photocatalysts for crucial organic transformation,such as aerobic oxidation,remains challenging.Although powdered porous materials offer abundant accessible active sites,their application in liquid-phase catalysis is often limited by insufficient light absorption and inevitable charge recombination,which are inherent drawbacks of conventional heterogeneous catalysts.Here,through rational design and nanoscale-engineering of porous aromatic frameworks(PAFs)comprising porphyrin and porous organic cage,a quasi-homogeneous porous photocatalyst with high catalytic activity and controllable dimension was developed.The interface-directed growth in oil-in-water emulsion shaped the morphology of photoactive PAFs from powders to nanoflakes,which facilitated the light absorbance and catalyst-substrate interaction.Compared with PAF powders,PAF nanoflakes exhibited superior photocatalytic activity for aerobic oxidation.For mustard gas simulant(2-chloroethyl ethyl sulfide,CEES),PAF nanoflakes exhibited ultrafast detoxification rates in room air with a half-life(t_(1/2))as fast as 26s,which even exceeded other catalysts in pure oxygen.It also completely catalyzed the aerobic oxidation of thioether within 15 min,which is almost the fastest rate among any reported organic photocatalysts.Furthermore,the efficient catalytic performance under mild conditions caused by improved light enrichment,surface charge transfer and carrier lifetime was elucidated.展开更多
The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative p...The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative potential of metal-organic frameworks(MOFs)as next-generation adsorbents for PM recovery,focusing on their synthesis,functionalization,and multiscale adsorption mechanisms.We critically analyze conventional pyrometallurgical and hydrometallurgical methods and highlight their limitations in terms of selectivity,energy consumption,and secondary pollution.In contrast,MOFs offer tunable porosity,abundant active sites,and tunable surface chemistry,enabling efficient PM capture via synergistic physical and chemical adsorption.Advanced modification techniques,including direct synthesis and post-synthetic modification,are reviewed to propose strategies for enhancing the adsorption kinetics and selectivity for Au,Ag,Pt,and Pd.Key structure-property relationships are established through multiscale characterization and thermodynamic models,revealing the critical roles of hierarchical porosity,soft donor atoms,and framework stability.Industrial challenges,such as aqueous stability and scalability,are addressed via Zr-O bond strengthening,hydrophobic functionalization,and support immobilization.This study consolidates the experimental and theoretical advances in MOF-based PM recovery and provides a roadmap for translating laboratory innovations into practical applications within the circular-economy framework.展开更多
This study presents a novel polyoxometalate(POM)constructed crystalline inorganic framework,featuring a 2D layered architecture with irregular porosity and inherent proton sources.This unique configuration establishes...This study presents a novel polyoxometalate(POM)constructed crystalline inorganic framework,featuring a 2D layered architecture with irregular porosity and inherent proton sources.This unique configuration establishes an intrinsic hydrogen bonding network that facilitates proton hopping(Grotthuss mechanism),achieving a[100]directional proton conductivity of 1.75×10^(-3)S cm^(-1)under a low relative humidity(RH)of 35%at 298 K.Notably,under elevated conditions(338 K,95%RH),it attains a superprotonic conductivity of 1.61 S cm^(-1),representing one of the highest values recorded for framework materials to date.Analysis of the molecular structure,pore geometry characteristics and topological connectivity,and water vapor adsorption experiment(offering proton diffusion coefficient),indicates that the exceptional water-mediated proton dynamics stem from the interlayer S-shaped irregular pore channels,which probably induce a siphon-like effect to significantly enhance the transport of hydrated protons under the vehicle mechanism.This work not only proposes a POM strategy for constructing 2D inorganic frameworks but also reveals the irregular pore channel-enhanced proton dynamics,providing new insights into the optimization of proton conductors.展开更多
Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystall...Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.展开更多
Cellulose frameworks have emerged as promising materials for light management due to their exceptional light-scattering capabilities and sustainable nature.Conventional biomass-derived cellulose frameworks face a fund...Cellulose frameworks have emerged as promising materials for light management due to their exceptional light-scattering capabilities and sustainable nature.Conventional biomass-derived cellulose frameworks face a fundamental trade-off between haze and transparency,coupled with impractical thicknesses(≥1 mm).Inspired by squid’s skin-peeling mechanism,this work develops a peroxyformic acid(HCOOOH)-enabled precision peeling strategy to isolate intact 10-μm-thick bamboo green(BG)frameworks—100×thinner than wood-based counterparts while achieving an unprecedented optical performance(88%haze with 80%transparency).This performance surpasses delignified biomass(transparency<40%at 1 mm)and matches engineered cellulose composites,yet requires no energy-intensive nanofibrillation.The preserved native cellulose I crystalline structure(64.76%crystallinity)and wax-coated uniaxial fibril alignment(Hermans factor:0.23)contribute to high mechanical strength(903 MPa modulus)and broadband light scattering.As a light-management layer in polycrystalline silicon solar cells,the BG framework boosts photoelectric conversion efficiency by 0.41%absolute(18.74%→19.15%),outperforming synthetic anti-reflective coatings.The work establishes a scalable,waste-to-wealth route for optical-grade cellulose materials in next-generation optoelectronics.展开更多
Three-dimensional supramolecular organic frameworks with precisely tunable pore sizes are highly demanded for a wide range of applications,e.g.,encapsulating enzymes to enhance their stability,activity,and reusability...Three-dimensional supramolecular organic frameworks with precisely tunable pore sizes are highly demanded for a wide range of applications,e.g.,encapsulating enzymes to enhance their stability,activity,and reusability.However,precise control and tune the pore size of such frameworks still remains a significant challenge to date.In this study,we constructed supramolecular polymer frameworks using rigid tetrahedral star polyisocyanides with tunable length and sufficiently narrow distribution as building block.First,a series of tetrahedral four-arm star polyisocyanides with controlled chain lengths and narrow molecular weight distributions was prepared via the Pd(Ⅱ)-catalyzed living isocyanide polymerization.Then 2-ureido-4[1H]-pyrimidinone(Upy) unit was installed onto each chain-end of polyisocyanide arms via post-polymerization functionalization.Leveraging the supramolecular hydrogen bonding interactions between the terminal Upy units,well-ordered supramolecular polymer frameworks were readily obtained.Notably,the pore size was dependent on the chain length of the polyisocyanide arms.Precisely control the chain length of polyisocyanide arms,supramolecular polymer frameworks with pore sizes ranging from 5.06 nm to 9.72 nm were achieved.These frameworks,with tunable and large pore apertures,demonstrated exceptional capabilities in encapsulating enzymes of different sizes,such as lipase(TL),horseradish peroxidase(HRP),and glucose oxidase(GOx).The encapsulated enzymes exhibited significantly enhanced catalytic activity and durability.Moreover,the frameworks' tunable and large pore apertures facilitated the co-encapsulation of multiple enzymes,enabling efficient dual-enzyme cascade reactions.展开更多
The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molec...The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molecular sieving emerges as the most promising approach,but it will be significantly compromised at high temperatures due to the significant thermal motion.Here,we report a thermally robust zinc-based metal-organic framework(MOF)that can be synthesized on sub-kilogram scale and achieve exceptional C_(3)H_(6)/C_(3)H_(8) separation performances across a broad temperature range(298–353 K).Unlike conventional MOFs suffering from thermal lattice expansion to give poorer selectivity,this new MOF gives the adsorption capacity of C_(3)H_(6)essentially unchanged and that of C_(3)H_(8) negligible at elevated temperatures,outperforming most state-of-the-art adsorbents,in virtue of multiple hydrogen bonds at the aperture.Column breakthrough experiments confirmed the excellent separation capability,and showed no performance degradation over multi-round adsorption-desorption cycles at 353 K.This study addresses the critical challenge of the trade-off between temperature and selectivity in adsorptive separation,which offers new insights into the design of porous structures for highly effective separation at high temperatures.展开更多
Redox-active porous aromatic frameworks(PAFs)have emerged as hopeful candidates for sodium-ion batteries(SIBs)in view of their porous structures,chemical stability and tunable architectures.Herein,we successfully synt...Redox-active porous aromatic frameworks(PAFs)have emerged as hopeful candidates for sodium-ion batteries(SIBs)in view of their porous structures,chemical stability and tunable architectures.Herein,we successfully synthesized two redox-active PAFs(PAF-305 and PAF-306)with different nitrogen-containing motifs,and demonstrated their application as cathode materials for SIBs.Density functional theory(DFT)calculations reveal that nitrogen-rich PAF-305 exhibits a lower lowest unoccupied molecular orbital(LUMO)energy level(-3.35 eV)and a narrower energy gap(E_(g))(2.40 eV)compared with nitrogen-poor PAF-306.As expected,PAF-305 displays outstanding electrochemical performance,comprising a high reversible capacity of 145.2 mAh g^(-1)at 0.05 A g^(-1)and satisfactory cycling stability with 92% capacity retention over 1000 cycles at 0.2 A g^(-1).Remarkably,PAF-305 maintains robust electrochemical properties across a wide temperature range(-20℃ to 50℃).Through a combination of experimental characterizations and theoretical calculations,the sodium-ion storage mechanism of PAF-305 is elucidated.This study not only provides a promising strategy for exploring other redox-active organic units in the design of novel PAFs,but also expands the potential applications of PAFs in energy storage systems.展开更多
Progressive skin fibrosis ultimately results in irreversible contractures,causing both joint dysfunction and cosmetic deformity.The key pathological features of skin fibrosis include persistent inflammation and abnorm...Progressive skin fibrosis ultimately results in irreversible contractures,causing both joint dysfunction and cosmetic deformity.The key pathological features of skin fibrosis include persistent inflammation and abnormal accumulation of the extracellular matrix(ECM),with epithelialmesenchymal transition(EMT)playing a critical role in disease progression.However,current therapeutic strategies for cutaneous fibrosis are largely palliative and often require repeated interventions,with limited efficacy.Celastrol(Cel)exerts anti-inflammatory and anti-fibrotic effects in skin tissue,but its clinical application is limited by poor bioavailability and a narrow therapeutic window.Tetrahedral framework nucleic acid(tFNA),a novel nanocarrier system,exhibits multiple advantages,including enhanced cellular uptake,improved cell viability,and intrinsic anti-fibrotic and anti-inflammatory properties.Therefore,this study applied tFNA-Cel complex(TCC)as an advanced nanotherapeutic agent,designed to exert a synergistic anti-fibrotic effect.In this study,an in vitro model of skin fibrosis was established using human keratinocyte(HaCaT)cells treated with 5 ng mL^(-1) transforming growth factor beta(TGF-β)for 24 h.The results showed that TCC significantly inhibited EMT progression by reducingα-smooth muscle actin(α-SMA)levels and increasing E-cadherin level.Compared to tFNA or Cel alone,TCC exhibited superior anti-fibrotic effects in the fibrosis model,as evidenced by modulation of SMAD family member 2(SMAD2)signaling and collagen I expression.Furthermore,the TCC group showed lower levels of nuclear factorκB p65(NF-κB p65),BCL-2-associated X protein(Bax),and reactive oxygen species(ROS)compared to the Cel or tFNA groups.These findings highlight TCC as a promising treatment for skin fibrosis,with its synergistic anti-fibrotic effects providing new therapeutic avenues.展开更多
CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organ...CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.展开更多
The practical deployment of lithium metal batteries remains severely constrained,especially under elevated temperatures.Although metal-organic frameworks(MOFs)improve the thermal stability of liquid electrolytes by ca...The practical deployment of lithium metal batteries remains severely constrained,especially under elevated temperatures.Although metal-organic frameworks(MOFs)improve the thermal stability of liquid electrolytes by capturing them in well-ordered sub-nanopores,interparticle voids between MOF particles readily absorb liquid electrolyte,obscuring our understanding of the intrinsic role of nanopores in directing Li^(+)transport.To address this challenge,we introduce a one-dimensional(1D)MOF model architecture that eliminates interparticle effects and enables direct observation of Li^(+)solvation and de-solvation dynamics.Comparative studies of 1D HKUST-1 and ZIF-8 uncover distinct transport behaviors,supported by both experimental measurements and neural network potential-based molecular dynamics simulations.Building on these insights,we construct a hierarchical core-shell MOF architecture by integrating ZIF-8(core)and HKUST-1(shell)onto a hybrid fiber scaffold.This design harnesses the complementary strengths of both MOFs to achieve continuous ion pathways,directional Li^(+)conduction,and improved thermal and electrochemical resilience.展开更多
The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Coval...The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.展开更多
The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theor...The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.展开更多
Two supramolecular organic frameworks(SOFs)have been constructed from the co-assembly of biimidazolium-derived octacationic components and cucurbit[8]uril in water.Dynamic light scattering and ^(1)H NMR experiments re...Two supramolecular organic frameworks(SOFs)have been constructed from the co-assembly of biimidazolium-derived octacationic components and cucurbit[8]uril in water.Dynamic light scattering and ^(1)H NMR experiments reveal that both SOFs can undergo reversible assembly and disassembly at room temperature.One of the SOFs displays unprecedently high maximum tolerated dose of 120 mg/kg with mice,which improves by 40%compared with the highest value of the reported SOFs.In vitro and in vivo tests show that the SOF can adsorb doxorubicin and overcome the resistance of multidrugresistant MDR A549/ADR tumor cells to realize intracellular delivery,leading to enhanced antitumor efficacy.Moreover,it can also completely inhibit the posttreatment phototoxicity of photofrin and fully neutralize the anticoagulation of both unfractionated heparin and low molecular weight heparins through efficient inclusion and elimination or sequestration mechanism.As the first examples that undergo roomtemperature reversible assembly and disassembly,the new SOFs in principle allow for quantitative analysis of the molecular components in the body that is prerequisite for preclinical evaluation in the future.展开更多
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
基金the Natural Science Foundation of ZhejiangProvince(No.LZ24B020005)the National Natural Science Foundation of China(No.22071040)for financial support.
文摘High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.
基金Liaoning Provincial Social Science Fund Key Disciplines Development Project,Research on the New Supply Function of Entrepreneurs Based on Innovation Ecosystems Driven by Data(Grant No.L22ZD061)。
文摘Accelerating the development of new quality productive forces(NQPF),with innovation at its core,has become essential for firm growth in the new era.Drawing on financial data from China's A-share listed companies spanning the period 2010–2023,this study empirically investigates the impact of entrepreneurial spirit on firm-level NQPF.The results indicate that entrepreneurial spirit significantly promotes firm-level NQPF.Mechanism analysis indicates that entrepreneurial effort—underpinned by technological capital accumulation,effective incentive and constraint mechanisms,and a competitive market environment—plays a mediating role in this relationship.Further heterogeneity analysis reveals that,amid China's economic transition,the positive effects of entrepreneurial spirit are more pronounced in non-state-owned enterprises,high-tech firms,and newly established firms.Accordingly,systematic efforts should be pursued across the technological,organizational,and environmental(TOE)dimensions to optimize the cultivation of entrepreneurial spirit.In particular,greater emphasis should be placed on productive entrepreneurial spirit and the constructive role of entrepreneurial effort,so as to fully leverage their contribution to the advancement of firm-level NQPF.
基金supported by the National Natural Science Foundation of China(22075040,U21A20330,22131004)the National Key R&D Program of China(2022YFB3805900)+2 种基金the Jilin Provincial Scientific and Technological Development Program(20240602105RC)the Innovation Platform for Academicians of Hainan Provincethe Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(YSPTZX202321)。
文摘The development of efficient photocatalysts for crucial organic transformation,such as aerobic oxidation,remains challenging.Although powdered porous materials offer abundant accessible active sites,their application in liquid-phase catalysis is often limited by insufficient light absorption and inevitable charge recombination,which are inherent drawbacks of conventional heterogeneous catalysts.Here,through rational design and nanoscale-engineering of porous aromatic frameworks(PAFs)comprising porphyrin and porous organic cage,a quasi-homogeneous porous photocatalyst with high catalytic activity and controllable dimension was developed.The interface-directed growth in oil-in-water emulsion shaped the morphology of photoactive PAFs from powders to nanoflakes,which facilitated the light absorbance and catalyst-substrate interaction.Compared with PAF powders,PAF nanoflakes exhibited superior photocatalytic activity for aerobic oxidation.For mustard gas simulant(2-chloroethyl ethyl sulfide,CEES),PAF nanoflakes exhibited ultrafast detoxification rates in room air with a half-life(t_(1/2))as fast as 26s,which even exceeded other catalysts in pure oxygen.It also completely catalyzed the aerobic oxidation of thioether within 15 min,which is almost the fastest rate among any reported organic photocatalysts.Furthermore,the efficient catalytic performance under mild conditions caused by improved light enrichment,surface charge transfer and carrier lifetime was elucidated.
基金supported by the National Natural Science Foundation of China(No.52304329)the Yunnan Fundamental Research Projects(No.202201BE070001-003),Guo Lin would like to acknowledge Xing Dian talent support program of Yunnan Province.
文摘The recovery of precious metals(PMs)from secondary resources is critical for addressing global supply-chain vulnerabilities and sustainable resource utilization.This review systematically examines the transformative potential of metal-organic frameworks(MOFs)as next-generation adsorbents for PM recovery,focusing on their synthesis,functionalization,and multiscale adsorption mechanisms.We critically analyze conventional pyrometallurgical and hydrometallurgical methods and highlight their limitations in terms of selectivity,energy consumption,and secondary pollution.In contrast,MOFs offer tunable porosity,abundant active sites,and tunable surface chemistry,enabling efficient PM capture via synergistic physical and chemical adsorption.Advanced modification techniques,including direct synthesis and post-synthetic modification,are reviewed to propose strategies for enhancing the adsorption kinetics and selectivity for Au,Ag,Pt,and Pd.Key structure-property relationships are established through multiscale characterization and thermodynamic models,revealing the critical roles of hierarchical porosity,soft donor atoms,and framework stability.Industrial challenges,such as aqueous stability and scalability,are addressed via Zr-O bond strengthening,hydrophobic functionalization,and support immobilization.This study consolidates the experimental and theoretical advances in MOF-based PM recovery and provides a roadmap for translating laboratory innovations into practical applications within the circular-economy framework.
基金supported by the National Natural Science Foundation of China(22271075,22171071)。
文摘This study presents a novel polyoxometalate(POM)constructed crystalline inorganic framework,featuring a 2D layered architecture with irregular porosity and inherent proton sources.This unique configuration establishes an intrinsic hydrogen bonding network that facilitates proton hopping(Grotthuss mechanism),achieving a[100]directional proton conductivity of 1.75×10^(-3)S cm^(-1)under a low relative humidity(RH)of 35%at 298 K.Notably,under elevated conditions(338 K,95%RH),it attains a superprotonic conductivity of 1.61 S cm^(-1),representing one of the highest values recorded for framework materials to date.Analysis of the molecular structure,pore geometry characteristics and topological connectivity,and water vapor adsorption experiment(offering proton diffusion coefficient),indicates that the exceptional water-mediated proton dynamics stem from the interlayer S-shaped irregular pore channels,which probably induce a siphon-like effect to significantly enhance the transport of hydrated protons under the vehicle mechanism.This work not only proposes a POM strategy for constructing 2D inorganic frameworks but also reveals the irregular pore channel-enhanced proton dynamics,providing new insights into the optimization of proton conductors.
基金supported by the National Key R&D Program of China(No.2023YFA1507204)National Natural Science Foundation ofChina(Nos.22475074,22171139,22225109,22302055)+4 种基金Natural Science Foundation of Guangdong Province(No.2023B1515020076)Key Scientific Research Project Plan of Colleges and Universities of Henan Province(No.24B150004)The Double Thousand Talents Plan of Jiangxi Province(No.jxsq2023102003)Project supported by the Guangdong Provincial Key Laboratory of Carbon Dioxide Resource Utilization(No.2024B121201001)Project supportedby the Major Research plan of the National Natural Science Foundation of China(No.92461310).
文摘Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.
基金supported by National Natural Science Foundation of China(32494793).
文摘Cellulose frameworks have emerged as promising materials for light management due to their exceptional light-scattering capabilities and sustainable nature.Conventional biomass-derived cellulose frameworks face a fundamental trade-off between haze and transparency,coupled with impractical thicknesses(≥1 mm).Inspired by squid’s skin-peeling mechanism,this work develops a peroxyformic acid(HCOOOH)-enabled precision peeling strategy to isolate intact 10-μm-thick bamboo green(BG)frameworks—100×thinner than wood-based counterparts while achieving an unprecedented optical performance(88%haze with 80%transparency).This performance surpasses delignified biomass(transparency<40%at 1 mm)and matches engineered cellulose composites,yet requires no energy-intensive nanofibrillation.The preserved native cellulose I crystalline structure(64.76%crystallinity)and wax-coated uniaxial fibril alignment(Hermans factor:0.23)contribute to high mechanical strength(903 MPa modulus)and broadband light scattering.As a light-management layer in polycrystalline silicon solar cells,the BG framework boosts photoelectric conversion efficiency by 0.41%absolute(18.74%→19.15%),outperforming synthetic anti-reflective coatings.The work establishes a scalable,waste-to-wealth route for optical-grade cellulose materials in next-generation optoelectronics.
基金The National Natural Science Foundation of China (NSFC,Nos.92256201,52273006,22071041,92356302,and 21971052)Natural Science Foundation of Jilin Province (No.20240101181JC) are gratefully appreciated for financial the supportssupported by the User Experiment Assist System of Shanghai Synchrotron Radiation Facility (SSRF)。
文摘Three-dimensional supramolecular organic frameworks with precisely tunable pore sizes are highly demanded for a wide range of applications,e.g.,encapsulating enzymes to enhance their stability,activity,and reusability.However,precise control and tune the pore size of such frameworks still remains a significant challenge to date.In this study,we constructed supramolecular polymer frameworks using rigid tetrahedral star polyisocyanides with tunable length and sufficiently narrow distribution as building block.First,a series of tetrahedral four-arm star polyisocyanides with controlled chain lengths and narrow molecular weight distributions was prepared via the Pd(Ⅱ)-catalyzed living isocyanide polymerization.Then 2-ureido-4[1H]-pyrimidinone(Upy) unit was installed onto each chain-end of polyisocyanide arms via post-polymerization functionalization.Leveraging the supramolecular hydrogen bonding interactions between the terminal Upy units,well-ordered supramolecular polymer frameworks were readily obtained.Notably,the pore size was dependent on the chain length of the polyisocyanide arms.Precisely control the chain length of polyisocyanide arms,supramolecular polymer frameworks with pore sizes ranging from 5.06 nm to 9.72 nm were achieved.These frameworks,with tunable and large pore apertures,demonstrated exceptional capabilities in encapsulating enzymes of different sizes,such as lipase(TL),horseradish peroxidase(HRP),and glucose oxidase(GOx).The encapsulated enzymes exhibited significantly enhanced catalytic activity and durability.Moreover,the frameworks' tunable and large pore apertures facilitated the co-encapsulation of multiple enzymes,enabling efficient dual-enzyme cascade reactions.
基金supported by the National Natural Science Foundation of China(22475240,22090061,22488101)the State Key Laboratory of Catalysis(2024SKL-A-010)。
文摘The separation of propylene(C_(3)H_(6))and propane(C_(3)H_(8))presents a significant industrial challenge due to their similar molecular dimensions and physicochemical properties.Among various separation methods,molecular sieving emerges as the most promising approach,but it will be significantly compromised at high temperatures due to the significant thermal motion.Here,we report a thermally robust zinc-based metal-organic framework(MOF)that can be synthesized on sub-kilogram scale and achieve exceptional C_(3)H_(6)/C_(3)H_(8) separation performances across a broad temperature range(298–353 K).Unlike conventional MOFs suffering from thermal lattice expansion to give poorer selectivity,this new MOF gives the adsorption capacity of C_(3)H_(6)essentially unchanged and that of C_(3)H_(8) negligible at elevated temperatures,outperforming most state-of-the-art adsorbents,in virtue of multiple hydrogen bonds at the aperture.Column breakthrough experiments confirmed the excellent separation capability,and showed no performance degradation over multi-round adsorption-desorption cycles at 353 K.This study addresses the critical challenge of the trade-off between temperature and selectivity in adsorptive separation,which offers new insights into the design of porous structures for highly effective separation at high temperatures.
基金supported by the Science&Technology Department of Jilin Province(20230508057RC)。
文摘Redox-active porous aromatic frameworks(PAFs)have emerged as hopeful candidates for sodium-ion batteries(SIBs)in view of their porous structures,chemical stability and tunable architectures.Herein,we successfully synthesized two redox-active PAFs(PAF-305 and PAF-306)with different nitrogen-containing motifs,and demonstrated their application as cathode materials for SIBs.Density functional theory(DFT)calculations reveal that nitrogen-rich PAF-305 exhibits a lower lowest unoccupied molecular orbital(LUMO)energy level(-3.35 eV)and a narrower energy gap(E_(g))(2.40 eV)compared with nitrogen-poor PAF-306.As expected,PAF-305 displays outstanding electrochemical performance,comprising a high reversible capacity of 145.2 mAh g^(-1)at 0.05 A g^(-1)and satisfactory cycling stability with 92% capacity retention over 1000 cycles at 0.2 A g^(-1).Remarkably,PAF-305 maintains robust electrochemical properties across a wide temperature range(-20℃ to 50℃).Through a combination of experimental characterizations and theoretical calculations,the sodium-ion storage mechanism of PAF-305 is elucidated.This study not only provides a promising strategy for exploring other redox-active organic units in the design of novel PAFs,but also expands the potential applications of PAFs in energy storage systems.
基金supported by the National Natural Science Foundation of China(82101077)Sichuan Science and Technology Program(2023NSFSC1516)+2 种基金West China School/Hospital of Stomatology Sichuan University(RCDWJS2023-5)Fundamental Research Funds for the Central UniversitiesResearch and Develop Program,West China School/Hospital of Stomatology Sichuan University。
文摘Progressive skin fibrosis ultimately results in irreversible contractures,causing both joint dysfunction and cosmetic deformity.The key pathological features of skin fibrosis include persistent inflammation and abnormal accumulation of the extracellular matrix(ECM),with epithelialmesenchymal transition(EMT)playing a critical role in disease progression.However,current therapeutic strategies for cutaneous fibrosis are largely palliative and often require repeated interventions,with limited efficacy.Celastrol(Cel)exerts anti-inflammatory and anti-fibrotic effects in skin tissue,but its clinical application is limited by poor bioavailability and a narrow therapeutic window.Tetrahedral framework nucleic acid(tFNA),a novel nanocarrier system,exhibits multiple advantages,including enhanced cellular uptake,improved cell viability,and intrinsic anti-fibrotic and anti-inflammatory properties.Therefore,this study applied tFNA-Cel complex(TCC)as an advanced nanotherapeutic agent,designed to exert a synergistic anti-fibrotic effect.In this study,an in vitro model of skin fibrosis was established using human keratinocyte(HaCaT)cells treated with 5 ng mL^(-1) transforming growth factor beta(TGF-β)for 24 h.The results showed that TCC significantly inhibited EMT progression by reducingα-smooth muscle actin(α-SMA)levels and increasing E-cadherin level.Compared to tFNA or Cel alone,TCC exhibited superior anti-fibrotic effects in the fibrosis model,as evidenced by modulation of SMAD family member 2(SMAD2)signaling and collagen I expression.Furthermore,the TCC group showed lower levels of nuclear factorκB p65(NF-κB p65),BCL-2-associated X protein(Bax),and reactive oxygen species(ROS)compared to the Cel or tFNA groups.These findings highlight TCC as a promising treatment for skin fibrosis,with its synergistic anti-fibrotic effects providing new therapeutic avenues.
文摘CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.RS-2023-00217581)supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(RS-2024-00406724)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(RS-2025-25430676)。
文摘The practical deployment of lithium metal batteries remains severely constrained,especially under elevated temperatures.Although metal-organic frameworks(MOFs)improve the thermal stability of liquid electrolytes by capturing them in well-ordered sub-nanopores,interparticle voids between MOF particles readily absorb liquid electrolyte,obscuring our understanding of the intrinsic role of nanopores in directing Li^(+)transport.To address this challenge,we introduce a one-dimensional(1D)MOF model architecture that eliminates interparticle effects and enables direct observation of Li^(+)solvation and de-solvation dynamics.Comparative studies of 1D HKUST-1 and ZIF-8 uncover distinct transport behaviors,supported by both experimental measurements and neural network potential-based molecular dynamics simulations.Building on these insights,we construct a hierarchical core-shell MOF architecture by integrating ZIF-8(core)and HKUST-1(shell)onto a hybrid fiber scaffold.This design harnesses the complementary strengths of both MOFs to achieve continuous ion pathways,directional Li^(+)conduction,and improved thermal and electrochemical resilience.
基金financially supported by the National Natural Science Foundation of China (No.51972302)。
文摘The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.
基金supported by the Fundamental Research Funds for the Liaoning Universities(Grant No.LJ202410166012).
文摘The Ordos Basin is a large superimposed hydrocarbon-bearing basin in China,and further research on the sedimentary characteristics and sedimentary evolution of the sequence framework of target layers is of great theoretical and practical significance for guiding oil and gas exploration.The sedimentary facies and sedimentary evolution of the high-resolution sequence framework of the Carboniferous Taiyuan Formation in the Hangjinqi area have been systematically analyzed for the first time by drilling,logging and seismic data.The results show that four types of sequence interfaces can be identified in the Taiyuan Formation:regional unconformity surfaces,scour surfaces,lithologic-lithofacies transformation surfaces and flooding surfaces.According to the sedimentary response caused by the upward and downward movements of the base level at different levels,the Taiyuan Formation can be divided into 2 long-term cycles(LSC_(1)-LSC_(2)),4 mid-term cycles(MSC_(1)-MSC4)and 7 short-term cycles(SSC_(1)-SSC7).The long-and mid-term cycles correspond to members T_(1)and T_(2)and layers T_(1)-1,T_(1-2),T_(2-1),and T_(2)-2,respectively.Long-term cycles are dominated by C_(1);mid-term cycles are dominated by C_(1)and C_(2),followed by A2;and short-term cycles are dominated by C_(1),C_(2),A1 and A2.Under the high-resolution sequence stratigraphic framework,the Hangjinqi area underwent a transformation of fan delta and tidal flat depositional systems during the Taiyuan Formation sedimentary period.In the MSC_(1)-MSC_(2)stage,owing to a large-scale paleocontinent,the fan delta sedimentary body,which was limited in scale and scope,developed only in the southeastern corner and gradually transitioned basinward to tidal flat facies.In the MSC3-MSC4 stage,as the paleocontinent continuously decreased and the sedimentary range expanded,fan-delta plain sedimentation began in the study area.Several braided distributary channels with poor connectivity developed on the fan-delta plain,and between them were floodplains and peat swamps.
基金the National Natural Science Foundation of China(No.21921003 for Z.T.L.and 22201293 for S.B.Y.)Shanghai Sailing Program(No.22YF1458300 for S.B.Y.)for financial support。
文摘Two supramolecular organic frameworks(SOFs)have been constructed from the co-assembly of biimidazolium-derived octacationic components and cucurbit[8]uril in water.Dynamic light scattering and ^(1)H NMR experiments reveal that both SOFs can undergo reversible assembly and disassembly at room temperature.One of the SOFs displays unprecedently high maximum tolerated dose of 120 mg/kg with mice,which improves by 40%compared with the highest value of the reported SOFs.In vitro and in vivo tests show that the SOF can adsorb doxorubicin and overcome the resistance of multidrugresistant MDR A549/ADR tumor cells to realize intracellular delivery,leading to enhanced antitumor efficacy.Moreover,it can also completely inhibit the posttreatment phototoxicity of photofrin and fully neutralize the anticoagulation of both unfractionated heparin and low molecular weight heparins through efficient inclusion and elimination or sequestration mechanism.As the first examples that undergo roomtemperature reversible assembly and disassembly,the new SOFs in principle allow for quantitative analysis of the molecular components in the body that is prerequisite for preclinical evaluation in the future.
