The growing demand for material properties in challenging environments has led to a surge of interest in rapid composition design. Given the great potential composition space, the field of high/medium entropy alloys (...The growing demand for material properties in challenging environments has led to a surge of interest in rapid composition design. Given the great potential composition space, the field of high/medium entropy alloys (H/MEAs) still lacks effective atomic-scale composition design and screening schemes, which hinders the accurate prediction of desired composition and properties. This study proposes a novel approach for rapidly designing the composition of materials with the aim of overcoming the trade-off between strength and ductility in metal matrix composites. The effect of chemical composition on stacking fault energy (SFE), shear modulus, and phase stability was investigated through the use of molecular dynamics (MD) and thermodynamic calculation software. The alloy's low SFE, highest shear modulus, and stable face-centered cubic (FCC) phase have been identified as three standard physical quantities for rapid screening to characterize the deformation mechanism, ultimate tensile strength, phase stability, and ductility of the alloy. The calculation results indicate that the optimal composition space is expected to fall within the ranges of 17 %–34 % Ni, 33 %–50 % Co, and 25 %–33 % Mn. The comparison of stress-strain curves for various predicted components using simulated and experimental results serves to reinforce the efficacy of the method. This indicates that the screening criteria offer a necessary design concept, deviating from traditional strategies and providing crucial guidance for the rapid development and application of MEAs.展开更多
A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention...A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention and a better resistance to thermal shock fatigue because of its role of the pores as crack arresters.A dense and coherent surface oxide layer leads to a significant benefit in residual strength during thermal fatigue, however, an increased fatigue number to 30 th cycle cannot cause a further influence although a thicker oxide layer presents, which is attributed to holes defect and disappearance of part intergranular phase.展开更多
The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monito...The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monitored directly with radiocarbon(14 C).In this research,annual plants[Setaria viridis(L.)Beauv.]were collected from 26 sites in 2013 and2014 in the central urban district of Xi’an City.The△14C content of the samples were analyzed using a 3 MV Accelerator Mass Spectrometer,and CO2ff concentrations were calculated based on mass balance equations.The results showed that the CO2ff mixing ratio ranged from 15.9 to 25.0 ppm(part per million,equivalent toμmol mol-1),with an average of 20.5 ppm in 2013.The range of measured values became larger in 2014,from 13.9 ppm to 33.1 ppm,with an average of 23.5 ppm.The differences among the average CO2ff concentrations between the central area and outer urban areas were not statistically significant.Although the year-to-year variation of the CO2ff concentration was significant(P<0.01),there was a distinctly low CO2 ff value observed in the northeast corner of the city.CO2 ff emiissions from vehicle exhaust and residential sources appeared to be more significant than two thermal power plants,according to our observed CO2 ff spatial distribution.The variation of pollution source transport recorded in our observations was likely controlled by southwesterly winds.These results could assist in the optimal placement of regional CO2 monitoring stations,and benefit the local government in the implementation of efficient carbon emission reduction measures.展开更多
This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed ...This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed using real-time quantitative polymerase chain reaction(RT-qPCR)within both the patient tissue specimens and glioblastoma cell lines.The relationship between lncRNA DPP10-AS1 expression in glioblastoma and patient prognosis was investigated.Cell Counting Kit-8(CCK-8),transwell,and clonogenic experiments were utilized to assess tumor cells’proliferation,invasiveness,and migratory potentials after lncRNA DPP10-AS1 expression was up or down-regulated.Using an online bioinformatics prediction tool,the intracellular localization of lncRNA DPP10-AS1 and its target miRNA were predicted,and RNA-FISH verified results.A dual-luciferase reporter experiment validated the relationship across miR-24-3p together with lncRNA DPP10-AS1.MiR-24-3p expression within glioblastoma was identified through RT-qPCR,and potential link across miR-24-3p and lncRNA DPP10-AS1 was assessed using Pearson correlation analysis.Moreover,influence from lncRNA DPP10-AS1/miR-24-3p axis upon glioblastoma cell progression was assessed in vivo via a subcutaneous xenograft tumor model.Results:The expression of lncRNA DPP10-AS1 was notably reduced in both surgical specimens of glioblastoma and the equivalent cell lines.Low level of lncRNA DPP10-AS1 in glioblastoma is following poor prognosis.The downregulation of lncRNA DPP10-AS1 in glioblastoma cells resulted in enhanced cellular proliferation,migration,and invasion capabilities,accompanied by downregulated E-cadherin and upregulated vimentin and N-cadherin.Additionally,the observed upregulation of lncRNA DPP10-AS1 demonstrated a substantial inhibitory function upon proliferation,invasion,and migratory capabilities of LN229 cells.Subcellular localization disclosed that lncRNA DPP10-AS1 had a binding site that interacted with miR-24-3p.Upregulated miR-24-3p was detected in glioblastomas,displaying an inverse correlation with lncRNA DPP10-AS1 expression.MiR-24-3p downstream target has been determined as chromodomain helicase DNA binding protein 5(CHD5).LncRNA DPP10-AS1 affected the invasion and proliferation of glioblastoma by controlling the miR-24-3p/CHD5 axis.Conclusion:The present study demonstrated that lncRNA DPP10-AS1 can inhibit the invasive,migratory,and proliferative properties of glioblastoma by regulating the miR-24-3p/CHD5 signaling pathway.Consequently,lncRNA DPP10-AS1 has potential as a tumor suppressor and might be utilized for accurate diagnosis and targeted treatments of glioblastomas.展开更多
CONSPECTUS:Cycloarenes,fully benzene-annelated macrocyclic systems with inward-facing carbon−hydrogen bonds,serve as ideal models for defects in graphene,offering great application potential in organic electronics,sup...CONSPECTUS:Cycloarenes,fully benzene-annelated macrocyclic systems with inward-facing carbon−hydrogen bonds,serve as ideal models for defects in graphene,offering great application potential in organic electronics,supramolecular chemistry,and optics.They offer an attractive combination of synthesis challenge,aesthetic appeal,fundamental problems,and potential applications.Initially,the most typical cycloarene,kekulene,was expected to provide a crucial experimental test to determine whetherπ-electrons are delocalized over the entire molecule or delocalized at the benzenoid rings.This question has captivated synthetic chemists for decades.After numerous failed attempts,Staab and Diederich achieved the first conclusive synthesis of kekulene in 1978.The deshielded inner protons in the 1H NMR spectrum conclusively demonstrated that theπ-electrons in cycloarenes are delocalized at individual benzenoid rings.However,owing to limited synthetic methods,complex reaction routes,and poor solubility of the final products,progress in cycloarene research has been slow.Over the next four decades,only a few contracted or expanded kekulene homologues were reported.Nevertheless,the changes in their chemical structure bring some exciting physicochemical properties.The enlargement of the central ring of kekulene induces a transition from a planar to a saddle-shaped structure,further influencing its electronic and optical properties and unlocking unexpected applications in supramolecular chemistry.Therefore,developing new rational synthetic methods to controllably synthesize structurally diverse cycloarenes is crucial.With the continuous development of synthetic science,in recent years,some functional cycloarenes and heteroatom-embedded heterocycloarenes have been reported.Owing to their unique topological structures,well-defined cavities,and large cyclic conjugated systems,these(hetero)cycloarenes have been applied in fields such as supramolecular chemistry,organic field-effect transistors,and solar cells.However,the limited understanding of the structure−property relationship in(hetero)cycloarenes poses a formidable challenge to their custom synthesis for specific functions.Herein,we review our efforts in the design,synthesis,and applications of cycloarenes and heterocycloarenes.First,we summarize four representative synthetic methods for cycloarenes.Subsequently,we present a comprehensive overview of three molecular design strategies:π-extension,heteroatom embedding,and acceptor moiety insertion,to achieve the molecular structure diversity of cycloarenes.Then,we highlight their synthetic methods,geometries,fundamental optoelectronic properties,and unique applications in ultranarrowband emission,organic transistor devices,and supramolecular chemistry.We also delve into the intrinsic correlations among structures,properties,and applications of these cycloarenes and heterocycloarenes.Finally,we envision further development of structural diversity in cycloarenes and heterocycloarenes alongside their potential applications in sensing,phase-transfer catalysis,drug delivery,and various optoelectronic devices.展开更多
Developing fully fusedπ-conjugated molecules with characteristic self-assembly and selective host–vip interaction by a wet chemistry approach remains very challenging.A series of fully fused thiophene-benzene alte...Developing fully fusedπ-conjugated molecules with characteristic self-assembly and selective host–vip interaction by a wet chemistry approach remains very challenging.A series of fully fused thiophene-benzene alternating ribbons,BDTh-nT(n=2–6),have been successfully synthesized.X-ray crystallography analysis indicates that BDTh-nT adopt nearly planar configurations,with sulfur atoms oriented regularly in theπ-conjugated skeleton.With the increase ofπ-conjugated length,the ability of self-assembly shows a trend of increasing while the host–vip binding between BDTh-nT and spherical vip C_(60)exhibits obvious selectivity.Only BDTh-4T with appropriateπ-conjugated length can be combined with the spherical vip C_(60)by shape recognition.In addition,it is worth noting that BDTh-nT show a conjugated-length-dependent photoreactivity,in which BDTh-4/5/6T can achieve a fluorescence transition from blue-violet to light yellow/blue-white/orange-yellow under the excitation of 365 nm ultraviolet light.Our investigations will not only shed light on the supramolecular chemistry but also provide a strategy for design and precise synthesis of thienoacenes with desirable properties.展开更多
The 2025 Nobel Prize in Chemistry has been awarded to the pioneers of metal-organic frameworks(MOFs),honoring Japanese chemist Susumu Kitagawa,Australian scientist Richard Robson,and American chemist Omar M.Yaghi,for ...The 2025 Nobel Prize in Chemistry has been awarded to the pioneers of metal-organic frameworks(MOFs),honoring Japanese chemist Susumu Kitagawa,Australian scientist Richard Robson,and American chemist Omar M.Yaghi,for creating these extraordinary molecular architectures.In a poetic summary,the Swedish Royal Academy of Sciences described their achievement:“They have created new rooms for chemistry.”[1].展开更多
Tris(2,4,6-trichlorophenyl)methyl (TTM) radical oligomers with different number of spin centers are designed and successfully synthesized through C–N/C–C coupling reaction using the diphenylamine group as building b...Tris(2,4,6-trichlorophenyl)methyl (TTM) radical oligomers with different number of spin centers are designed and successfully synthesized through C–N/C–C coupling reaction using the diphenylamine group as building block. The strong intramolecular charge transfer (ICT) interactions endow radical oligomers with obvious absorption and emission bands in near-infrared regions. Impressively, the strong electron-deficient property of TTM core and single bond linking mode between the adjacent diphenylamine spacers greatly contribute to the formation of intramolecular isolated redox centers. Accordingly, after the treatment of chemical equivalent NO•SbF_(6) oxidant, polyradicals are converted directly to the corresponding highest oxidation state along with the formation of quinoidal structure cation, which can be verified by UV spectra and single crystal analysis. This study develops a facile design rule for the construction of TTM-based polyradicals and provides the reference for oxidation process and mechanism of polyradical open shell molecules with the weak electron coupling systems.展开更多
Helicenes are a quintessential class of aromatic molecules characterized by their inherent chirality.In recent years,helicene-derived macrocycles have attracted significant attention and witnessed rapid advancements d...Helicenes are a quintessential class of aromatic molecules characterized by their inherent chirality.In recent years,helicene-derived macrocycles have attracted significant attention and witnessed rapid advancements due to their unique conjugated geometries and topological structures,which endow them with intriguing properties such as chirality,selfassembly,and supramolecular organization.However,these macrocycles still face several challenges,including synthetic difficulties stemming from high strain energy,a limited understanding of structureproperty relationships,and restricted practical applications.This review is the first to highlight recent progress in helicene-derived macrocycles,categorizing them based on their geometric configurations.It provides an in-depth analysis of their synthetic strategies and explores the correlation between their structures and properties.Furthermore,the potential future directions and applications are discussed.展开更多
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray as...As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.展开更多
The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector pl...The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.展开更多
Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundament...Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope （HE） onboard Insight-HXMT （Hard X-ray Modulation Telescope） is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart （SSS17a/AT2017gfo） with very large collection area （M000 cm2） and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity （TOO） observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy （0.2-5 MeV） radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.展开更多
Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be ...Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer.However,highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered.Here,we developed a noveSIRT6 allosteric inhibitor,compound 11e,with maximal inhibitory potency and an IC_(50) value of 0.98±0.13μmol/L.Moreover,compound 11e exhibited significant selectivity against other histone deacetylases(HADC1-11 and SIRT1-3)at concentrations up to 100μmol/L.The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses.Importantly,we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis.To our knowledge,this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer.It not only provides a promising lead compound for subsequent inhibitor developmentargeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.展开更多
By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economica...By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economically feasible on industrial scales,exploring and engineering cyanobacterial chassis and cell factories with fast growth rates and carbon fixation activities facing environmental stresses are of great significance.To simplify and accelerate the screening for fast-growing cyanobacteria strains,a method called Individual Cyanobacteria Vitality Tests and Screening(iCyanVS)was established.We show that the ^(13)C incorporation ratio of carotenoids can be used to measure differences in cell growth and carbon fixation rates in individual cyanobacterial cells of distinct genotypes that differ in growth rates in bulk cultivations,thus greatly accelerating the process screening for fastest-growing cells.The feasibility of this approach is further demonstrated by phenotypically and then genotypically identifying individual cyanobacterial cells with higher salt tolerance from an artificial mutant library via Raman-activated gravity-driven encapsulation and sequencing.Therefore,this method should find broad applications in growth rate or carbon intake rate based screening of cyanobacteria and other photosynthetic cell factories.展开更多
Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are p...Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are photoautotrophic microorganisms that are the main sources of primary productivity in the biosphere.Cyanobacteria,the only prokaryotic microalgae,have also been considered as promising chassis for photosynthetic biosynthesis,directly converting solar energy and CO_(2)into various bio-based products.This technological route is called photosynthetic biomanufacturing,and is advantageous to simultaneous carbon fixation and clean production.This review focuses on development mode,application and suggests trends related to the further development of photosynthetic biomanufacturing.With regard to the link between photosynthetic CO_(2)fixation and the production of desired metabolites,we summarized and compared three widely adopted strategies.“Screening to find”,screening a large number of high-quality cyanobacterial resources and analyzing their intracellular metabolites are of significance for screening novel cyanobacterial species with high-value chemicals and properties of industrial relevance.“Engineering to modify”,the emergence and application of synthetic biological tools and metabolic engineering strategies have enhanced the ability to modify different cyanobacterial species to reshape more carbon to flow toward synthetic tailored chemicals.“Stressing to activate”,through special culture conditions and strategies,combined with omics analysis techniques,silent metabolic pathways and functional modules are activated to induce the accumulation of high-value chemicals.This review provides valid and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production,providing specific feasible solutions for net zero emissions.展开更多
The fatty alk（a/e）ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygena...The fatty alk（a/e）ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygenase （cADO）, which catalyzes the conversion of Cn fatty aldehyde to its corresponding Cn-1 alk（ale）ne, is a key enzyme in that pathway. Due to its low activity, alk（a/e）ne production by cADO is an inefficient process. Previous biochemical and structural investi. gations of cADO have provided some information on its catalytic reaction. However, the details of its cata- lytic processes remain unclear. Here we report five crystal structures of cADO from the Synechococcus elongates strain PCC7942 in both its iron-free and iron-bound forms, representing different states during its catalytic process. Structural comparisons and functional enzyme assays indicate that Giu144, one of the iron-coordinating residues, plays a vital role in the catalytic reaction of cADO. Moreover, the helix where Glu144 resides exhibits two distinct conformations that correlates with the different binding states of the di-iron center in cADO structures. Therefore, our results provide a structural explanation for the highly labile feature of cADO di-iron center, which we pro- posed to be related to its low enzymatic activity. On the basis of our structural and biochemical data, a possible catalytic process of cADO was proposed, which could aid the design of cADO with improved activity.展开更多
Polymer semiconductors with highly crystalline forms,such as crystalline nanowires and fibers,are critical for charge carrier transport in organic field-effect transistors(OFET).However,the highly crystalline form usu...Polymer semiconductors with highly crystalline forms,such as crystalline nanowires and fibers,are critical for charge carrier transport in organic field-effect transistors(OFET).However,the highly crystalline form usually requires high-quality molecular orderliness,which still remains a great challenge,especially in single fibers of extremely high-molecular-weight semiconducting polymers.In this study,we present an anodic aluminum oxide(AAO)template-assisted method to fabricate highly crystalline N-alkyl diketopyrrolopyrrole dithienylthieno[3,2-b]thiophene(DPP-DTT)single fibers.Grazing-incidence X-ray diffraction and selected area electron diffraction show obvious diffraction patterns for single-crystal-like characteristics,indicating the highly ordered molecular chains and highly crystalline structures of the single DPP-DTT fibers.OFET based on the single-crystal-like DPP-DTT fiber exhibits the highest charge carrier mobility of up to 14.2 cm^(2)V^(−1)s^(-1)and an average mobility of approximately 7.8 cm^(2)V^(−1)s^(-1),which is significantly improved compared with DPP-DTT thin film-based devices.Besides,the fiber-based OFET also exhibit a high light responsivity of 4.0.103 A W^(−1).This work demonstrates a facile and effective method for fabricating single-crystal-like fibers of high-molecular-weight polymer semiconductors and corresponding high-performance OFET devices.Furthermore,it also expands application of AAO template method for achieving crystalline semiconducting polymer fibers and provide a new perspective for the study on polymer crystallization.展开更多
A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic ph...A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic photoresponsive behaviors and intriguing supramolecular assembling properties.The smallest macro-cycle AzoM-1-E with a rigid planar conjugated backbone structure is used to prepare the single crystal transistors,showing reversible optical tunability.The moderate size macrocycle AzoM-2-E assembles into a dimer in the form of interpenetration throughπ-πstacking between azobenzene units.The largest macrocycle AzoM-3-E with enhancedflexibility can adaptively assemble with various types of electron-deficient vips accompanied by distortion of azobenzene.Typically,AzoM-3-E assembles with the planar F4-TCNQ to form a tetragonal geometry by C-F⋅⋅⋅π and π-π interactions,while the assembly with ellipsoidal C70 viaπ-πinteractions induces AzoM-3-E to form a boat-shaped geometry.This work will shed new light on the development of functional conjugated macrocycles in organic electronics.展开更多
A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obta...A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obtained TTM radical derivatives are extremely stable during chromatography purification and long-term storage in the solid state.展开更多
基金funding from the National Natural Science Foundation of China(Nos.52063017 and 52061025)the Major Science and Technology Project of Gansu Province(Nos.22ZD6GA008 and 20ZD7GJ008)+3 种基金the Natural Science Foundation of Gansu Province(No.23JRRA820)The Science and Technology Project of Major Science and Technology Project of Gansu Province(No.22ZD6GA008)the Science and Technology Project of Gansu Province(No.23YFGA0058)the College Industry Support Plan of Gansu Province(No.2023CYZC-27).
文摘The growing demand for material properties in challenging environments has led to a surge of interest in rapid composition design. Given the great potential composition space, the field of high/medium entropy alloys (H/MEAs) still lacks effective atomic-scale composition design and screening schemes, which hinders the accurate prediction of desired composition and properties. This study proposes a novel approach for rapidly designing the composition of materials with the aim of overcoming the trade-off between strength and ductility in metal matrix composites. The effect of chemical composition on stacking fault energy (SFE), shear modulus, and phase stability was investigated through the use of molecular dynamics (MD) and thermodynamic calculation software. The alloy's low SFE, highest shear modulus, and stable face-centered cubic (FCC) phase have been identified as three standard physical quantities for rapid screening to characterize the deformation mechanism, ultimate tensile strength, phase stability, and ductility of the alloy. The calculation results indicate that the optimal composition space is expected to fall within the ranges of 17 %–34 % Ni, 33 %–50 % Co, and 25 %–33 % Mn. The comparison of stress-strain curves for various predicted components using simulated and experimental results serves to reinforce the efficacy of the method. This indicates that the screening criteria offer a necessary design concept, deviating from traditional strategies and providing crucial guidance for the rapid development and application of MEAs.
基金financial support of the project from the National Natural Science Foundation of China (Nos. 51272206 and 51472198)the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1280)+2 种基金the National Key Laboratory Functional Composite (No. 9140C560109130C56201)the Fundamental Research Funds for the Central University (No. xkjc2014009)the State Key Laboratory for Mechanical Behavior of Materials (No. 20121207)
文摘A water-quenching technique has been adopted to evaluate thermal shock fracture and fatigue behaviors of porous Si3N4 ceramics in an air atmosphere. The high-porosity Si3N4 ceramics exhibit a higher strength retention and a better resistance to thermal shock fatigue because of its role of the pores as crack arresters.A dense and coherent surface oxide layer leads to a significant benefit in residual strength during thermal fatigue, however, an increased fatigue number to 30 th cycle cannot cause a further influence although a thicker oxide layer presents, which is attributed to holes defect and disappearance of part intergranular phase.
基金supported by the National Natural Science Foundation of China(Grant No.NSFC41730108,41773141,41573136,and 41991250)National Research Program for Key Issues in Air Pollution Control(Grant No.DQGG0105-02)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23010302)the Youth Innovation Promotion Association CAS(Grant No.2016360)the Natural Science Basic Research Program of Shaanxi(Program No.2019JCW-20)。
文摘The need for atmospheric carbon dioxide(CO2)reduction in the context of global warming is widely acknowledged by the global scientific community.Fossil fuel CO2(CO2ff)emissions occur mainly in cities,and can be monitored directly with radiocarbon(14 C).In this research,annual plants[Setaria viridis(L.)Beauv.]were collected from 26 sites in 2013 and2014 in the central urban district of Xi’an City.The△14C content of the samples were analyzed using a 3 MV Accelerator Mass Spectrometer,and CO2ff concentrations were calculated based on mass balance equations.The results showed that the CO2ff mixing ratio ranged from 15.9 to 25.0 ppm(part per million,equivalent toμmol mol-1),with an average of 20.5 ppm in 2013.The range of measured values became larger in 2014,from 13.9 ppm to 33.1 ppm,with an average of 23.5 ppm.The differences among the average CO2ff concentrations between the central area and outer urban areas were not statistically significant.Although the year-to-year variation of the CO2ff concentration was significant(P<0.01),there was a distinctly low CO2 ff value observed in the northeast corner of the city.CO2 ff emiissions from vehicle exhaust and residential sources appeared to be more significant than two thermal power plants,according to our observed CO2 ff spatial distribution.The variation of pollution source transport recorded in our observations was likely controlled by southwesterly winds.These results could assist in the optimal placement of regional CO2 monitoring stations,and benefit the local government in the implementation of efficient carbon emission reduction measures.
基金supported through the Natural Science Foundation of Jiangsu Province(No.BK20201172)the Key Project of the Jiangsu Health Commission(No.ZDB2020016)the Jiangsu Province Key Research and Development Program:Social Development Project(No.BE2021653).
文摘This investigation aimed to unveil new prospective diagnosis-related biomarkers together with treatment targets against glioblastoma.Methods:The expression levels of long non-coding RNA(lncRNA)DPP10-AS1 were assessed using real-time quantitative polymerase chain reaction(RT-qPCR)within both the patient tissue specimens and glioblastoma cell lines.The relationship between lncRNA DPP10-AS1 expression in glioblastoma and patient prognosis was investigated.Cell Counting Kit-8(CCK-8),transwell,and clonogenic experiments were utilized to assess tumor cells’proliferation,invasiveness,and migratory potentials after lncRNA DPP10-AS1 expression was up or down-regulated.Using an online bioinformatics prediction tool,the intracellular localization of lncRNA DPP10-AS1 and its target miRNA were predicted,and RNA-FISH verified results.A dual-luciferase reporter experiment validated the relationship across miR-24-3p together with lncRNA DPP10-AS1.MiR-24-3p expression within glioblastoma was identified through RT-qPCR,and potential link across miR-24-3p and lncRNA DPP10-AS1 was assessed using Pearson correlation analysis.Moreover,influence from lncRNA DPP10-AS1/miR-24-3p axis upon glioblastoma cell progression was assessed in vivo via a subcutaneous xenograft tumor model.Results:The expression of lncRNA DPP10-AS1 was notably reduced in both surgical specimens of glioblastoma and the equivalent cell lines.Low level of lncRNA DPP10-AS1 in glioblastoma is following poor prognosis.The downregulation of lncRNA DPP10-AS1 in glioblastoma cells resulted in enhanced cellular proliferation,migration,and invasion capabilities,accompanied by downregulated E-cadherin and upregulated vimentin and N-cadherin.Additionally,the observed upregulation of lncRNA DPP10-AS1 demonstrated a substantial inhibitory function upon proliferation,invasion,and migratory capabilities of LN229 cells.Subcellular localization disclosed that lncRNA DPP10-AS1 had a binding site that interacted with miR-24-3p.Upregulated miR-24-3p was detected in glioblastomas,displaying an inverse correlation with lncRNA DPP10-AS1 expression.MiR-24-3p downstream target has been determined as chromodomain helicase DNA binding protein 5(CHD5).LncRNA DPP10-AS1 affected the invasion and proliferation of glioblastoma by controlling the miR-24-3p/CHD5 axis.Conclusion:The present study demonstrated that lncRNA DPP10-AS1 can inhibit the invasive,migratory,and proliferative properties of glioblastoma by regulating the miR-24-3p/CHD5 signaling pathway.Consequently,lncRNA DPP10-AS1 has potential as a tumor suppressor and might be utilized for accurate diagnosis and targeted treatments of glioblastomas.
基金financially supported by the National Natural Science Foundation of China(22322502)the National Key R&D Program of China(2023YFB3609000)the Natural Science Foundation of Shanghai(22ZR1405800 and 23ZR1405100).
文摘CONSPECTUS:Cycloarenes,fully benzene-annelated macrocyclic systems with inward-facing carbon−hydrogen bonds,serve as ideal models for defects in graphene,offering great application potential in organic electronics,supramolecular chemistry,and optics.They offer an attractive combination of synthesis challenge,aesthetic appeal,fundamental problems,and potential applications.Initially,the most typical cycloarene,kekulene,was expected to provide a crucial experimental test to determine whetherπ-electrons are delocalized over the entire molecule or delocalized at the benzenoid rings.This question has captivated synthetic chemists for decades.After numerous failed attempts,Staab and Diederich achieved the first conclusive synthesis of kekulene in 1978.The deshielded inner protons in the 1H NMR spectrum conclusively demonstrated that theπ-electrons in cycloarenes are delocalized at individual benzenoid rings.However,owing to limited synthetic methods,complex reaction routes,and poor solubility of the final products,progress in cycloarene research has been slow.Over the next four decades,only a few contracted or expanded kekulene homologues were reported.Nevertheless,the changes in their chemical structure bring some exciting physicochemical properties.The enlargement of the central ring of kekulene induces a transition from a planar to a saddle-shaped structure,further influencing its electronic and optical properties and unlocking unexpected applications in supramolecular chemistry.Therefore,developing new rational synthetic methods to controllably synthesize structurally diverse cycloarenes is crucial.With the continuous development of synthetic science,in recent years,some functional cycloarenes and heteroatom-embedded heterocycloarenes have been reported.Owing to their unique topological structures,well-defined cavities,and large cyclic conjugated systems,these(hetero)cycloarenes have been applied in fields such as supramolecular chemistry,organic field-effect transistors,and solar cells.However,the limited understanding of the structure−property relationship in(hetero)cycloarenes poses a formidable challenge to their custom synthesis for specific functions.Herein,we review our efforts in the design,synthesis,and applications of cycloarenes and heterocycloarenes.First,we summarize four representative synthetic methods for cycloarenes.Subsequently,we present a comprehensive overview of three molecular design strategies:π-extension,heteroatom embedding,and acceptor moiety insertion,to achieve the molecular structure diversity of cycloarenes.Then,we highlight their synthetic methods,geometries,fundamental optoelectronic properties,and unique applications in ultranarrowband emission,organic transistor devices,and supramolecular chemistry.We also delve into the intrinsic correlations among structures,properties,and applications of these cycloarenes and heterocycloarenes.Finally,we envision further development of structural diversity in cycloarenes and heterocycloarenes alongside their potential applications in sensing,phase-transfer catalysis,drug delivery,and various optoelectronic devices.
基金supported by the National Natural Science Foundation of China(grant no.22322502)the National Key R&D Program of China(grant no.2023YFB3609000)the Natural Science Foundation of Shanghai(grant nos.22ZR1405800 and 23ZR1405100).
文摘Developing fully fusedπ-conjugated molecules with characteristic self-assembly and selective host–vip interaction by a wet chemistry approach remains very challenging.A series of fully fused thiophene-benzene alternating ribbons,BDTh-nT(n=2–6),have been successfully synthesized.X-ray crystallography analysis indicates that BDTh-nT adopt nearly planar configurations,with sulfur atoms oriented regularly in theπ-conjugated skeleton.With the increase ofπ-conjugated length,the ability of self-assembly shows a trend of increasing while the host–vip binding between BDTh-nT and spherical vip C_(60)exhibits obvious selectivity.Only BDTh-4T with appropriateπ-conjugated length can be combined with the spherical vip C_(60)by shape recognition.In addition,it is worth noting that BDTh-nT show a conjugated-length-dependent photoreactivity,in which BDTh-4/5/6T can achieve a fluorescence transition from blue-violet to light yellow/blue-white/orange-yellow under the excitation of 365 nm ultraviolet light.Our investigations will not only shed light on the supramolecular chemistry but also provide a strategy for design and precise synthesis of thienoacenes with desirable properties.
文摘The 2025 Nobel Prize in Chemistry has been awarded to the pioneers of metal-organic frameworks(MOFs),honoring Japanese chemist Susumu Kitagawa,Australian scientist Richard Robson,and American chemist Omar M.Yaghi,for creating these extraordinary molecular architectures.In a poetic summary,the Swedish Royal Academy of Sciences described their achievement:“They have created new rooms for chemistry.”[1].
基金supported by the National Key Research and Development Program of China(2023YFB3609000)the National Natural Science Foundation of China(22322502,22475050,and 22171053)the Natural Science Foundation of Shanghai(24ZR1490600,22ZR1405800,and 23ZR1405100).
文摘Tris(2,4,6-trichlorophenyl)methyl (TTM) radical oligomers with different number of spin centers are designed and successfully synthesized through C–N/C–C coupling reaction using the diphenylamine group as building block. The strong intramolecular charge transfer (ICT) interactions endow radical oligomers with obvious absorption and emission bands in near-infrared regions. Impressively, the strong electron-deficient property of TTM core and single bond linking mode between the adjacent diphenylamine spacers greatly contribute to the formation of intramolecular isolated redox centers. Accordingly, after the treatment of chemical equivalent NO•SbF_(6) oxidant, polyradicals are converted directly to the corresponding highest oxidation state along with the formation of quinoidal structure cation, which can be verified by UV spectra and single crystal analysis. This study develops a facile design rule for the construction of TTM-based polyradicals and provides the reference for oxidation process and mechanism of polyradical open shell molecules with the weak electron coupling systems.
基金supported by the National Key R&D Program of China(grant no.2023YFB3609000)the National Natural Science Foundation of China(grant no.22322502)the Natural Science Foundation of Shanghai(grant no.23ZR1405100).
文摘Helicenes are a quintessential class of aromatic molecules characterized by their inherent chirality.In recent years,helicene-derived macrocycles have attracted significant attention and witnessed rapid advancements due to their unique conjugated geometries and topological structures,which endow them with intriguing properties such as chirality,selfassembly,and supramolecular organization.However,these macrocycles still face several challenges,including synthetic difficulties stemming from high strain energy,a limited understanding of structureproperty relationships,and restricted practical applications.This review is the first to highlight recent progress in helicene-derived macrocycles,categorizing them based on their geometric configurations.It provides an in-depth analysis of their synthetic strategies and explores the correlation between their structures and properties.Furthermore,the potential future directions and applications are discussed.
基金project funded by China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)support from the National Key Research and Development Program of China(Grant No.2016YFA0400800)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400)the National Natural Science Foundation of China(Grant Nos.U1838201,and U1838102).
文摘As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
基金China National Space Administration(CNSA)and the Chinese Academy of Sciences(CAS)the National Key Research and Development Program of China(Grant No.2016YFA0400800)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA04010202,XDA04010300,and XDB23040400).
文摘The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.
基金supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400800)from the Ministry of Science and Technology of China(MOST)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB23040400)the Hundred Talent Program of Chinese Academy of Sciences,the National Natural Science Foundation of China(Grant Nos.11233001,11503027,11403026,11473027,and11733009)
文摘Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope （HE） onboard Insight-HXMT （Hard X-ray Modulation Telescope） is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart （SSS17a/AT2017gfo） with very large collection area （M000 cm2） and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity （TOO） observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy （0.2-5 MeV） radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
基金supported by the National Key R&D Program of China(grant no.2022YFF1203005)the National Natural Science Foundation of China(22237005,81903458,82273425)+1 种基金Innovative research team of high-level local universities in Shanghai(SHSMU-ZDCX20212700,China)China Postdoctoral Science Foundation(2019M660090)。
文摘Pancreatic cancer,one of the most aggressive malignancies,has no effective treatment due to the lack of targets and drugs related to tumour metastasis.SIRT6 can promote the migration of pancreatic cancer and could be a potential target for antimetastasis of pancreatic cancer.However,highly selective and potency SIRT6 inhibitor that can be used in vivo is yet to be discovered.Here,we developed a noveSIRT6 allosteric inhibitor,compound 11e,with maximal inhibitory potency and an IC_(50) value of 0.98±0.13μmol/L.Moreover,compound 11e exhibited significant selectivity against other histone deacetylases(HADC1-11 and SIRT1-3)at concentrations up to 100μmol/L.The allosteric site and the molecular mechanism of inhibition were extensively elucidated by cocrystal complex structure and dynamic structural analyses.Importantly,we confirmed the antimetastatic function of such inhibitors in four pancreatic cancer cell lines as well as in two mouse models of pancreatic cancer liver metastasis.To our knowledge,this is the first study to reveal the in vivo effects of SIRT6 inhibitors on liver metastatic pancreatic cancer.It not only provides a promising lead compound for subsequent inhibitor developmentargeting SIRT6 but also provides a potential approach to address the challenge of metastasis in pancreatic cancer.
基金supported by the National Key Research and Development Program of China(Grant number 2021YFA0909700)the National Natural Science Foundation of China(Grant numbers 32070084,32270103,32271484,32300058)+3 种基金the Youth Innovation Promotion Association CAS(to Guodong Luan)Postdoctoral Innovation Project of Shandong Province(Grant number SDCX-ZG-202202036)Postdoctoral Science Foundation of China(Grant number 2021M703320)the Shandong Taishan Scholarship(to Xuefeng Lu,and to Guodong Luan).
文摘By directly converting solar energy and carbon dioxide into biobased products,cyanobacteria are promising chassis for photosynthetic biosynthesis.To make cyanobacterial photosynthetic biosynthesis technology economically feasible on industrial scales,exploring and engineering cyanobacterial chassis and cell factories with fast growth rates and carbon fixation activities facing environmental stresses are of great significance.To simplify and accelerate the screening for fast-growing cyanobacteria strains,a method called Individual Cyanobacteria Vitality Tests and Screening(iCyanVS)was established.We show that the ^(13)C incorporation ratio of carotenoids can be used to measure differences in cell growth and carbon fixation rates in individual cyanobacterial cells of distinct genotypes that differ in growth rates in bulk cultivations,thus greatly accelerating the process screening for fastest-growing cells.The feasibility of this approach is further demonstrated by phenotypically and then genotypically identifying individual cyanobacterial cells with higher salt tolerance from an artificial mutant library via Raman-activated gravity-driven encapsulation and sequencing.Therefore,this method should find broad applications in growth rate or carbon intake rate based screening of cyanobacteria and other photosynthetic cell factories.
基金supported by the National Key Research and Development Program of China(Grant number 2021YFA0909700,to X.L.and G.L.)the Youth Innovation Promotion Association CAS(to G.L.)+2 种基金the National Natural Science Foundation of China(Grant number 32070084 to G.L.,32270103 to G.L.,32271484 to X.L.,32300058 to J.C.)the DNL Cooperation Fund,CAS(DNL202014,to G.L.)the Shandong Taishan Scholarship(to X.L.and G.L.).
文摘Developing efficient CO_(2)utilization technologies can alleviate the urgent pressure on energy and the environment.Moreover,these technologies are crucial for achieving the goal of net zero emissions.Microalgae are photoautotrophic microorganisms that are the main sources of primary productivity in the biosphere.Cyanobacteria,the only prokaryotic microalgae,have also been considered as promising chassis for photosynthetic biosynthesis,directly converting solar energy and CO_(2)into various bio-based products.This technological route is called photosynthetic biomanufacturing,and is advantageous to simultaneous carbon fixation and clean production.This review focuses on development mode,application and suggests trends related to the further development of photosynthetic biomanufacturing.With regard to the link between photosynthetic CO_(2)fixation and the production of desired metabolites,we summarized and compared three widely adopted strategies.“Screening to find”,screening a large number of high-quality cyanobacterial resources and analyzing their intracellular metabolites are of significance for screening novel cyanobacterial species with high-value chemicals and properties of industrial relevance.“Engineering to modify”,the emergence and application of synthetic biological tools and metabolic engineering strategies have enhanced the ability to modify different cyanobacterial species to reshape more carbon to flow toward synthetic tailored chemicals.“Stressing to activate”,through special culture conditions and strategies,combined with omics analysis techniques,silent metabolic pathways and functional modules are activated to induce the accumulation of high-value chemicals.This review provides valid and updated information to facilitate the development of photosynthetic biosynthesis route with carbon fixation and clean production,providing specific feasible solutions for net zero emissions.
基金We would like to thank Yi Han and Shengquan Liu at the Institute of Biophysics, CAS and the staffs at Shanghai Synchrotron Radiation Facility and Photo Factory, Japan, respectively, for help during X-ray data collection. We also thank Wei Shao at Beijing Center for Physical and Chemical Analysis for help with the GC analysis, Zhen Xue at Institute of Botany, CAS for providing help for the GC-QqQ- MS/MS analysis, and Hongzhi Zhang at Institute of Geographic Sciences and Natural Resources Research, CAS for technical support with the metal content analysis by ICP-OES. This work was supported by the National Basic Research Program （973 Program） （Nos. 2011CBA00902 and 2011CBA00907）, Strategic Priority Research Program of the Chinese Academy of Sciences （XDB08020302）, National Natural Science Foundation of China（Grant Nos. 31021062 and 31170765）, and CAS Cross and Coop- eration Team for Scientific Innovation （Y31102110A）.
文摘The fatty alk（a/e）ne biosynthesis pathway found in cyanobacteria gained tremendous attention in recent years as a promising alternative approach for biofuel production. Cyanobacterial aldehyde-deformylating oxygenase （cADO）, which catalyzes the conversion of Cn fatty aldehyde to its corresponding Cn-1 alk（ale）ne, is a key enzyme in that pathway. Due to its low activity, alk（a/e）ne production by cADO is an inefficient process. Previous biochemical and structural investi. gations of cADO have provided some information on its catalytic reaction. However, the details of its cata- lytic processes remain unclear. Here we report five crystal structures of cADO from the Synechococcus elongates strain PCC7942 in both its iron-free and iron-bound forms, representing different states during its catalytic process. Structural comparisons and functional enzyme assays indicate that Giu144, one of the iron-coordinating residues, plays a vital role in the catalytic reaction of cADO. Moreover, the helix where Glu144 resides exhibits two distinct conformations that correlates with the different binding states of the di-iron center in cADO structures. Therefore, our results provide a structural explanation for the highly labile feature of cADO di-iron center, which we pro- posed to be related to its low enzymatic activity. On the basis of our structural and biochemical data, a possible catalytic process of cADO was proposed, which could aid the design of cADO with improved activity.
基金the National Natural Science Foundation of China(Grant No.61890940,51903051)the Natural Science Foundation of Shanghai(Grant 22ZR1407800).
文摘Polymer semiconductors with highly crystalline forms,such as crystalline nanowires and fibers,are critical for charge carrier transport in organic field-effect transistors(OFET).However,the highly crystalline form usually requires high-quality molecular orderliness,which still remains a great challenge,especially in single fibers of extremely high-molecular-weight semiconducting polymers.In this study,we present an anodic aluminum oxide(AAO)template-assisted method to fabricate highly crystalline N-alkyl diketopyrrolopyrrole dithienylthieno[3,2-b]thiophene(DPP-DTT)single fibers.Grazing-incidence X-ray diffraction and selected area electron diffraction show obvious diffraction patterns for single-crystal-like characteristics,indicating the highly ordered molecular chains and highly crystalline structures of the single DPP-DTT fibers.OFET based on the single-crystal-like DPP-DTT fiber exhibits the highest charge carrier mobility of up to 14.2 cm^(2)V^(−1)s^(-1)and an average mobility of approximately 7.8 cm^(2)V^(−1)s^(-1),which is significantly improved compared with DPP-DTT thin film-based devices.Besides,the fiber-based OFET also exhibit a high light responsivity of 4.0.103 A W^(−1).This work demonstrates a facile and effective method for fabricating single-crystal-like fibers of high-molecular-weight polymer semiconductors and corresponding high-performance OFET devices.Furthermore,it also expands application of AAO template method for achieving crystalline semiconducting polymer fibers and provide a new perspective for the study on polymer crystallization.
基金National Key R&D Program of China,Grant/Award Number:2018YFA0703200National Natural Science Foundation of China,Grant/Award Numbers:61890940,52073063+1 种基金Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher LearningNatural Science Foundation of Shanghai,Grant/Award Numbers:22ZR1405800,23ZR1405100。
文摘A series of newπ-conjugated macrocycles(AzoM-n-E,n 1–3)incorporating=azobenzene units have been synthesized by a facile strategy in one-pot reaction.The resultant azobenzene-embedded macrocycles feature intrinsic photoresponsive behaviors and intriguing supramolecular assembling properties.The smallest macro-cycle AzoM-1-E with a rigid planar conjugated backbone structure is used to prepare the single crystal transistors,showing reversible optical tunability.The moderate size macrocycle AzoM-2-E assembles into a dimer in the form of interpenetration throughπ-πstacking between azobenzene units.The largest macrocycle AzoM-3-E with enhancedflexibility can adaptively assemble with various types of electron-deficient vips accompanied by distortion of azobenzene.Typically,AzoM-3-E assembles with the planar F4-TCNQ to form a tetragonal geometry by C-F⋅⋅⋅π and π-π interactions,while the assembly with ellipsoidal C70 viaπ-πinteractions induces AzoM-3-E to form a boat-shaped geometry.This work will shed new light on the development of functional conjugated macrocycles in organic electronics.
基金supported by the National Key Research and Development Program of China(nos.2018YFA0703200 and 2018YFA0209401)the National Natural Science Foundation of China(nos.61890940,52073063,51903052,and 21733003)+1 种基金the Shanghai Pujiang Project(no.19PJ1400700),the Natural Science Foundation of Shanghai(no.21ZR1409600)the Program for Professor of Special Appointment(Eastern Scholar)at the Shanghai Institutions of Higher Learning.
文摘A mild one-step radical-to-radical synthetic strategy has been developed to directly produce a new family of diarylamine-substituted tris(2,4,6-trichlorophenyl)methyl(TTM)radicals TTM-DPA,TTM-DBPA,and TTM-DFA.The obtained TTM radical derivatives are extremely stable during chromatography purification and long-term storage in the solid state.
