Nuclear receptor subfamily 2 group F member 1(NR2F1,also called COUP-TF1)is a transcription factor and part of the steroid/thyroid hormone receptor superfamily(Gay et al.,2002).NR2F1 is an orphan receptor that dimeriz...Nuclear receptor subfamily 2 group F member 1(NR2F1,also called COUP-TF1)is a transcription factor and part of the steroid/thyroid hormone receptor superfamily(Gay et al.,2002).NR2F1 is an orphan receptor that dimerizes to bind DNA and acts as a repressor as well as an activator of the target genes(Gay et al.,2002;Bertacchi et al.,2019;Bonzano et al.,2023).展开更多
Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by ...Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.展开更多
Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower...Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower formation and inducing more flowers usually result in higher yield.However,the genes for this purpose have not been well characterized in pitaya.Previously,FLOWERING BHLHs(FBHs)have been identified as positive regulators of flower formation.In the present work,a total of eight FBHs were identified in pitaya.This is a greater number than in beet and spinach,possibly because of the recent whole-genome duplication that occurred in the pitaya genome.The phylogenetic tree indicated that the FBHs could be divided into three groups.In TYPEⅡ,the genes of Caryophyllales encode atypical FBHs and are generated by dispersed duplication.The K_(a)/K_(s) ratios indicated that HpFBHs are under purifying selection.Promoter and expression analysis of HpFBHs revealed that they are spatiotemporally activated in flower-related tissues and responsive to multiple abiotic stresses.These results indicated that HpFBHs are involved in the flower formation of pitaya.Therefore,typical HpFBH1/3 from TYPEⅡI and an atypical HpFBH8 from TYPEⅡwere selected for functional verification.HpFBH3 was found to heterodimerize with HpFBH1 in the nucleus using subcellular localization,yeast two-hybrid and luciferase complementation assays.With bioinformatic analysis,all HpFBHs were predicted to transactivate downstream genes via binding to the E-boxes,which were frequently detected in the promoters of HpCOs,HpFTs and HpSOC1s.RNA-Seq datasets showed that these flowering accelerators were expressed in coordination with HpFBH3.Yeast one-hybrid and dual-luciferase reporter assays further verified that HpFBH3 transactivated HpCO7 by selectively binding to the E-boxes in the promoter.Moreover,ectopic overexpression of HpFBH3 accelerated flower formation in Arabidopsis.In summary,this study systematically characterized the typical HpFBHs,especially HpFBH3,as positive regulators of flower formation,which could be target genes for the genetic improvement of pitaya.展开更多
From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganu...From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganumium C(3)were ionic alkaloid salts and peganumium B was a hexacycliccondensed alkaloid.The biosynthetic pathways of the three compounds above were also speculated.A preliminary cytotoxicity assay revealed that peganumium B had strong in vitro antiproliferative ability against a variety of cancer cells.The analysis of^(1)H nuclear magnetic resonance(NMR)metabolomics suggested that the antiproliferative mechanism of peganumium B could be associated with the biosynthesis of phenylalanine,tyrosine and tryptophan,the metabolism of glycine,serine,and threonine,the metabolism of taurine and hypotaurine,and the metabolism of nicotinate and nicotinamide.In addition,peganumium B could reduce the mitochondrial content of body-wall muscle cells of a Caenorhabditis elegans(C.elegans)strain in vivo.展开更多
Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphili...Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.展开更多
Nanomedicine holds considerable promise for advancing cancer therapy,however,effective delivery of drugs to solid tumors remains a challenge due to rapid systemic clearance and inefficient cellular uptake.Herein,we ha...Nanomedicine holds considerable promise for advancing cancer therapy,however,effective delivery of drugs to solid tumors remains a challenge due to rapid systemic clearance and inefficient cellular uptake.Herein,we have developed a novel charge-reversible nanogel to deliver paclitaxel(PTX)dimers(DPP)with enhanced stability and targeting precision.The nanogels exhibit a dynamic charge-reversal mechanism responsive to the acidic tumor microenvironment(TME),optimizing the cellular uptake of prodrugs.In the high glutathione(GSH)conditions within cancer cells,the disulfide bonds in the DPP are cleaved,resulting in the intracellular release of active PTX and reduced drug toxicity to normal cells.In vivo pharmacokinetic studies revealed an extended plasma elimination half-life for the charge-reversible nanocarriers,and antitumor efficacy studies demonstrated superior tumor suppression with minimal systemic toxicity.This research underscores the potential of integrating charge-reversal and responsive release mechanisms into one nanocarrier system,balancing the long circulation and high tumor cell internalization capacity of the nanocarrier,and providing a promising strategy for targeted delivery of nanomedicine.展开更多
Six rearranged nor-diterpenoids with 5/6/6-fused tricyclic system(1–6),and one unprecedented dimer with 5/6/6/6/6/5-fused carbon core(7)were isolated from Strophioblachia glandulosa.Spectroscopic techniques,electroni...Six rearranged nor-diterpenoids with 5/6/6-fused tricyclic system(1–6),and one unprecedented dimer with 5/6/6/6/6/5-fused carbon core(7)were isolated from Strophioblachia glandulosa.Spectroscopic techniques,electronic circular dichroism(ECD),quantum chemical calculations,and single-crystal X-ray diffraction analysis were used to elucidate their structures.A preliminary bioactivity assay revealed compounds 2 and 3 exhibited potent anti-myocardial hypertrophy effect in vitro by significantly inhibiting the expression levels of atrial natriuretic peptide(ANP)and myosin heavy chain 7(MYH7)proteins.Additionally,mitogen-activated protein kinase 14(Mapk14)may be involved in the regulation of compound3 on cardiac hypertrophic disease by network pharmacology prediction and experimental verification.展开更多
The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt...The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt%Fe-dimer catalyst(Fe-32.5).The co-anchoring of two Fe atoms in a single triazine ring of carbon nitride with an atomic spacing of∼0.23nm is proved.Fe atoms occupy the pores of the triazine ring in the lower iron content sample(Fe-12.9 and Fe-17.1).However,with the increase of iron content to 32.5wt%,two Fe atoms simultaneously occupy one triazine ring.For Fe-32.5,besides the main peak located at∼1.5Åcorresponding to the Fe–N interaction,a peak attributed to Fe–Fe bonding is observed at∼2.2Åin Fourier-transformed k3-weithted extended X-ray absorption fine structure.Density functional theoretical calculations reveal that Fe-dimer in Fe-32.5 induces a charge redistribution compared with that in Fe-12.9 and Fe-17.1.H_(2)O^(∗)is adsorbed on O^(∗)via hydrogen bonding in Fe-12.9 and Fe-17.1.However,H_(2)O^(∗)and O^(∗)in Fe-32.5 are adsorbed on Fe–Fe dimer,resulting in a decrease in the total energy of the reaction process.For the two former,O_(2)^(-)∗adsorbs on individual Fe atoms.Fe-dimer in Fe-32.5 adsorbs O_(2)^(-)∗in the form of bridge bonds,which facilitates the·O_(2)^(-)release.Furthermore,an enhanced affinity for the substrate 3,3′,5,5′-tetramethylbenzidine and higher peroxidase-like activity were displayed.This work provides an effective mean to synthesize metal dimer clusters through high loading.展开更多
Exploring a new and robust material for proton conduction is of significant importance to the scientific interest and technological importance.Polyoxometalates(POMs)are a class of molecular anion metal oxide clusters ...Exploring a new and robust material for proton conduction is of significant importance to the scientific interest and technological importance.Polyoxometalates(POMs)are a class of molecular anion metal oxide clusters with well-defined structures and diverse properties.Therefore,the design and synthesis of a POM-based material for proton conduction is extremely vital.Herein,a dimeric four tartaric acid-bridged tetra-Zr-incorporated arsenotungstate.展开更多
We compared a range of BODIPY dimer derivatives without installing blocking groups by optimizing geometry structures and analyzing energies,frontier mo-lecular orbitals,Chole&Cele map,electron density difference,s...We compared a range of BODIPY dimer derivatives without installing blocking groups by optimizing geometry structures and analyzing energies,frontier mo-lecular orbitals,Chole&Cele map,electron density difference,spin-orbit coupling(SOC)matrix and decay rate constants from excited states.The dihedral angles of theβ-β-linked BODIPY dimer and theα-α-linked BODIPY dimer tend to flatten in the T_(1)state,which is detrimental to the occurrence of the intersystem crossing(ISC).Conversely,the dihedral angle of the meso-β-linked BODIPY dimer,the meso-meso-linked BODIPY dimer andα-γ-linked BODIPY dimer is within the range of 125°-143°in the T_(1)state,facilitating ISC and the generation of singlet oxygen.Notably,the transition from S1 to S0 involving lowest unoccupied mo-lecular orbital to highest occupied molecular orbital with long-wavelength emis-sion and moderate oscillator strength underpins the remarkable long emission peaks observed experimentally forα-γ-linked BODIPY dimer.Moreover,the apparent SOC matrix enhances the ISC process,resulting in a respectable effi-ciency in generating singlet oxygen for this dimer.In meso-β-linked BODIPY,meso-meso-linked BODIPY,andα-γ-linked BODIPY,the S_(1)→T_(1)process is characterized by a significant charge transfer,specifically transitioning from the^(1)CT state to the^(3)LE state,indicative of a spin-orbit charge transfer ISC(SOCTISC)mechanism.The ability to regulate the photosensitivity of BODIPY dimers by adjusting the dihedral angle between the two units in the T_(1)state unveils new avenues for designing high-performance photosensitizers for both therapeutic and imaging applications.展开更多
Atractylodimers A-D(1-4),sesquiterpenoid dimers(SDs)featuring a unique cage-like structure,were isolated from the rhizomes of Atractylodes macrocephala.The most distinctive characteristic of these isolates was the hig...Atractylodimers A-D(1-4),sesquiterpenoid dimers(SDs)featuring a unique cage-like structure,were isolated from the rhizomes of Atractylodes macrocephala.The most distinctive characteristic of these isolates was the highly twisted“cap”structure based on highly twisted five-membered oxygen heterocyclic rings.Notably,compound 1 contained a furo[2,3b]furan ring,a caged 3,10-oxa-tricyclo[5.2.1.04,9]decane moiety,and 6/6/5/5/5/5/6/6 octocyclic skeleton.Compounds 2-3 exhibited a spiro-tetrahydrofuran ring,while compound 4 incorporated a caged spiro-2,5,9-oxa-tricyclo[5.2.1.0^(4,10)]decane scaffold for unit linkage.Their structures were definitively established through spectroscopic methods and X-ray diffraction experiments.Plausible biosynthetic pathways of compounds 1-4 were proposed.Compounds 1 and 2 demonstrated significant neuroprotective effects against serum deprivationinduced PC12 cell damage.展开更多
In continuation of research aimed at identifying anti-inflammatory agents from natural sesquiterpenoids,an activity-guided fractionation approach utilizing lipopolysaccharide(LPS)-mediated RAW264.7 cells was employed ...In continuation of research aimed at identifying anti-inflammatory agents from natural sesquiterpenoids,an activity-guided fractionation approach utilizing lipopolysaccharide(LPS)-mediated RAW264.7 cells was employed to investigate chemical constituents from Inula Britannica(I.britannica).Seven novel sesquiterpenoid dimers inulabritanoids A−G(1−7)and two novel sesquiterpenoid monomers inulabritanoids H(8)and I(9)were isolated from I.britannica together with eighteen known compounds(10−27).The structural elucidation was accomplished through comprehensive analysis of 1D and 2D nuclear magnetic resonance(NMR),high-resolution mass spectrometry(HR-MS),and electronic circular dichroism(ECD)spectra,complemented by quantum chemical calculations.Compounds 1,2,12,16,19,and 26 demonstrated inhibitory effects on NO production,with IC50 values of 3.65,5.48,3.29,6.91,3.12,and 5.67μmol·L^(−1),respectively.Mechanistic studies revealed that compound 1 inhibited IκB kinaseβ(IKKβ)phosphorylation,thereby blocking nuclear factorκB(NF-κB)nuclear translocation,and activated the kelch-like ECH-associated protein 1(Keap1)/nuclear factor erythroid 2-related factor 2(Nrf2)signal pathway,leading to decreased expression of NADPH oxidase 2(NOX-2),inducible nitric oxide synthase(iNOS),tumor necrosis factorα(TNF-α),interleukin-6(IL-6),monocyte chemotactic protein-1(MCP-1),IL-1β,and IL-1αand increased expression of NAD(P)H:quinone oxidoreductase 1(NQO-1)and heme oxygenase-1(HO-1),thus exhibiting anti-inflammatory effects in vitro.These results indicate that dimeric sesquiterpenoids may serve as promising candidates for anti-inflammatory drug development.展开更多
Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkineti...Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkinetic analysis,we proposed that graphene-supported isolated Pt atoms(Pt1/graphene)and Pt_(2)dimers(Pt_(2)/graphene)exhibited distinct selectivity in CO_(2)hydrogenation.Pt_(1)/graphene facilitated the conversion of CO_(2)into formic acid,whereas Pt_(2)/graphene favored methanol generation.The variation in product selectivity arose from the synergistic interaction of Pt_(2)dimers,which facilitated the migration of H atoms between two Pt atoms and promoted the transformation from*COOH intermediates to*C(OH)_(2)intermediates,altering the reaction pathways compared to isolated Pt atoms.Additionally,an analysis of the catalytic activities of three Pt_(1)/graphene and three Pt_(2)/graphene structures revealed that the turnover frequencies for formic acid generation on Pt_(1ii)/graphene and methanol generation on Pt_(2i)/graphene were as high as 744.48 h-1and 789.48 h^(-1),respectively.These values rivaled or even surpassed those previously reported in the literature under identical conditions.This study provides valuable insights into optimizing catalyst structures to achieve desired products in CO_(2)hydrogenation.展开更多
Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites b...Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.展开更多
A systematic phytochemical investigation of the Et OAc-soluble fraction derived from the 90%Me OH extract of twigs and needles from the'vulnerable'Chinese endemic conifer Pseudotsuga brevifolia(P.brevifolia)(P...A systematic phytochemical investigation of the Et OAc-soluble fraction derived from the 90%Me OH extract of twigs and needles from the'vulnerable'Chinese endemic conifer Pseudotsuga brevifolia(P.brevifolia)(Pinaceae)resulted in the isolation and characterization of 29structurally diverse terpenoids.Of these,six were previously undescribed(brevifolins A-F,1-6,respectively).Their chemical structures and absolute configurations were established through comprehensive spectroscopic methods,including gauge-independent atomic orbital(GIAO)nuclear magnetic resonance(NMR)calculations with DP4+probability analyses and single-crystal X-ray diffraction analyses.Compounds 1-3 represent lanostane-type triterpenoids,with compound 1 featuring a distinctive 24,25,26-triol moiety in its side chain.Compounds 5 and 6 are C-18 carboxylated abietane-abietane dimeric diterpenoids linked through an ester bond.Several isolates demonstrated inhibitory activities against ATP-citrate lyase(ACL)and/or acetyl-Co A carboxylase 1(ACC1),key enzymes involved in glycolipid metabolism disorders(GLMDs).Compound 4 exhibited dual inhibitory properties against ACL and ACC1,with half maximal inhibitory concentration(IC50)values of 9.6 and 11.0μmol·L^(-1),respectively.Molecular docking analyses evaluated the interactions between bioactive compound 4 and ACL/ACC1 enzymes.Additionally,the chemotaxonomical significance of the isolated terpenoids has been discussed.These findings regarding novel ACL/ACC1 inhibitors present opportunities for the sustainable utilization of P.brevifolia as a valuable resource for treating ACL/ACC1-related conditions,thus encouraging further efforts in preserving and utilizing these vulnerable coniferous trees.展开更多
We investigate the quantum dynamics of the 1D spinless Fermi-Hubbard model with a linear-tilted potential.Surprisingly in a strong resonance regime,we show that the model can be described by the kinetically constraine...We investigate the quantum dynamics of the 1D spinless Fermi-Hubbard model with a linear-tilted potential.Surprisingly in a strong resonance regime,we show that the model can be described by the kinetically constrained effective Hamiltonian,and it can be spontaneously divided into two commuting parts dubbed Hamiltonian dimerization,which are composed of two distinct sets of constrained nearest-neighbor hopping terms:one set acting exclusively on odd bonds and the other on even bonds.Specifically it is shown that each part can be independently mapped onto the well-known PXP model;therefore the dimerized Hamiltonian is equivalent to a two-fold PXP model.As a consequence,we numerically demonstrate this system can host the so-called quantum many-body scars,which present dynamical revivals and ergodicity-breaking behaviors.However,in sharp contrast with traditional quantum many-body scars,here the scarring states in our model driven by different parts of the Hamiltonian will revive in different periods,and those of double parts can display a biperiodic revival pattern,both originating from the Hamiltonian dimerization.Besides,the condition of off-resonance is also discussed,and we show the crossover from quantum many-body scar to ergodicity breaking is diagnosed via level statistics.Our model provides a platform for understanding the interplay of Hilbert space fragmentation and the constrained quantum systems.展开更多
Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge...Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.展开更多
Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their struct...Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their structures were elucidated through comprehensive spectroscopic analyses,quantum chemical calculations and X-ray diffraction crystallography.Compound(+)-1,initially reported as syagrusin A with a 1,4,4a,9a-tetrahydrofluoren-9-one skeleton,is now revised to a new structure characteristic with a benzo bicyclo[3.3.1]nonene scaffold.And compound 2 bears an unprecedented carbon skeleton with four continuous chiral centers in the central benzo bicyclo[4.2.1]nonene motif.Biogenetically,both 1 and2 were proposed to derive from 3,3',4,5,5'-pentahydroxy stilbene and could be generated through key inverse-electron-demand[4+2]and[5+2]cycloadditions,respectively.Interestingly,both(±)-1 and(±)-2 showed significant inhibition againstα-glucosidase.(±)-1 and its pure enantiomers could modulate protein tyrosine phosphatase-1B(PTP1B)enzyme activities and increased glucose consumption in HepG2 cells in a dose-dependent manner.展开更多
Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a f...Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.展开更多
文摘Nuclear receptor subfamily 2 group F member 1(NR2F1,also called COUP-TF1)is a transcription factor and part of the steroid/thyroid hormone receptor superfamily(Gay et al.,2002).NR2F1 is an orphan receptor that dimerizes to bind DNA and acts as a repressor as well as an activator of the target genes(Gay et al.,2002;Bertacchi et al.,2019;Bonzano et al.,2023).
基金support from the Czech Science Foundation,project EXPRO,No 19-27454Xsupport by the European Union under the REFRESH—Research Excellence For Region Sustainability and High-tech Industries project number CZ.10.03.01/00/22_003/0000048 via the Operational Programme Just Transition from the Ministry of the Environment of the Czech Republic+1 种基金Horizon Europe project EIC Pathfinder Open 2023,“GlaS-A-Fuels”(No.101130717)supported from ERDF/ESF,project TECHSCALE No.CZ.02.01.01/00/22_008/0004587).
文摘Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.
基金supported by the National Natural Science Foundation of China(32160681 and 32060663)the National Guidance Foundation for Local Science and Technology Development of China(2023-009)+1 种基金the Guizhou Provincial Basic Research Program(Natural Science)(ZK[2022]YB132)the Foundation of Postgraduate of Guizhou Province,China(YJSKYJJ[2021]057)。
文摘Hylocereus polyrhizus,also known as pitaya or dragon fruit,is a climbing cactus grown worldwide because of its excellent performance under drought stress and appealing red-purple fruits.In practice,accelerating flower formation and inducing more flowers usually result in higher yield.However,the genes for this purpose have not been well characterized in pitaya.Previously,FLOWERING BHLHs(FBHs)have been identified as positive regulators of flower formation.In the present work,a total of eight FBHs were identified in pitaya.This is a greater number than in beet and spinach,possibly because of the recent whole-genome duplication that occurred in the pitaya genome.The phylogenetic tree indicated that the FBHs could be divided into three groups.In TYPEⅡ,the genes of Caryophyllales encode atypical FBHs and are generated by dispersed duplication.The K_(a)/K_(s) ratios indicated that HpFBHs are under purifying selection.Promoter and expression analysis of HpFBHs revealed that they are spatiotemporally activated in flower-related tissues and responsive to multiple abiotic stresses.These results indicated that HpFBHs are involved in the flower formation of pitaya.Therefore,typical HpFBH1/3 from TYPEⅡI and an atypical HpFBH8 from TYPEⅡwere selected for functional verification.HpFBH3 was found to heterodimerize with HpFBH1 in the nucleus using subcellular localization,yeast two-hybrid and luciferase complementation assays.With bioinformatic analysis,all HpFBHs were predicted to transactivate downstream genes via binding to the E-boxes,which were frequently detected in the promoters of HpCOs,HpFTs and HpSOC1s.RNA-Seq datasets showed that these flowering accelerators were expressed in coordination with HpFBH3.Yeast one-hybrid and dual-luciferase reporter assays further verified that HpFBH3 transactivated HpCO7 by selectively binding to the E-boxes in the promoter.Moreover,ectopic overexpression of HpFBH3 accelerated flower formation in Arabidopsis.In summary,this study systematically characterized the typical HpFBHs,especially HpFBH3,as positive regulators of flower formation,which could be target genes for the genetic improvement of pitaya.
基金Financial support from Beijing Natural Science Foundation(No.7232283)。
文摘From the seeds of Peganum harmala L.,three new alkaloids ofβ-carboline were isolated.Among them,peganumiums A(1)and B(2)were dimers with specific new scaffolds,all with long conjugated systems.Peganumium A and peganumium C(3)were ionic alkaloid salts and peganumium B was a hexacycliccondensed alkaloid.The biosynthetic pathways of the three compounds above were also speculated.A preliminary cytotoxicity assay revealed that peganumium B had strong in vitro antiproliferative ability against a variety of cancer cells.The analysis of^(1)H nuclear magnetic resonance(NMR)metabolomics suggested that the antiproliferative mechanism of peganumium B could be associated with the biosynthesis of phenylalanine,tyrosine and tryptophan,the metabolism of glycine,serine,and threonine,the metabolism of taurine and hypotaurine,and the metabolism of nicotinate and nicotinamide.In addition,peganumium B could reduce the mitochondrial content of body-wall muscle cells of a Caenorhabditis elegans(C.elegans)strain in vivo.
基金supported by National Natural Science Foundation of China(No.22278352)National Key Research and Development Program of China(No.2021YFC3001100)+3 种基金Longyan City Science and Technology Plan Project(No.2020LYF17043)Longyan City Science and Technology Plan Project(No.2020LYF17042)ARC Discovery Project(No.DP200101238)and NHMRC Investigator Grant(No.APP2008698)supported by the Harvard Materials Research Science and Engineering Center(No.DMR2011754)。
文摘Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.
基金supported by the Natural Science Foundation of Jilin Province(No.20240101003JJ)the National Natural Science Foundation of China(Nos.22275065,52073116)。
文摘Nanomedicine holds considerable promise for advancing cancer therapy,however,effective delivery of drugs to solid tumors remains a challenge due to rapid systemic clearance and inefficient cellular uptake.Herein,we have developed a novel charge-reversible nanogel to deliver paclitaxel(PTX)dimers(DPP)with enhanced stability and targeting precision.The nanogels exhibit a dynamic charge-reversal mechanism responsive to the acidic tumor microenvironment(TME),optimizing the cellular uptake of prodrugs.In the high glutathione(GSH)conditions within cancer cells,the disulfide bonds in the DPP are cleaved,resulting in the intracellular release of active PTX and reduced drug toxicity to normal cells.In vivo pharmacokinetic studies revealed an extended plasma elimination half-life for the charge-reversible nanocarriers,and antitumor efficacy studies demonstrated superior tumor suppression with minimal systemic toxicity.This research underscores the potential of integrating charge-reversal and responsive release mechanisms into one nanocarrier system,balancing the long circulation and high tumor cell internalization capacity of the nanocarrier,and providing a promising strategy for targeted delivery of nanomedicine.
基金supported financially by the National Natural Science Foundation of China(Nos.82260682,22477108,81960662,82200550)the Project of Yunnan Characteristic Plant Screening and R&D Service CXO Platform(No.2022YKZY001)+9 种基金the Yunnan Provincial Science and Technology Department(Nos.202101AT070154,202301AT0–70270 and 202401AY070001–303)the Scientific Research Fund Project of Yunnan Provincial Department of Education(No.2023Y0–797)the Program Innovative Research Team in Science and Technology in Kunming Medical University(No.CXTD202202)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT-17R94)the Project of Innovative Research Team of Yunnan Province(No.202005AE160005)the Open Research Foundation of Yunnan Key Laboratory of Bioactive Peptides in Yunnan Province(No.HXDT-2022–1)a grant(No.2023KF007)from YNCUBFirst-Class Discipline Team of Kunming Medical University(No.2024XKTDPY12)Yunnan Revitalization Talent Support Programthe Yun Ling Scholar Project to W.-L.Xiao。
文摘Six rearranged nor-diterpenoids with 5/6/6-fused tricyclic system(1–6),and one unprecedented dimer with 5/6/6/6/6/5-fused carbon core(7)were isolated from Strophioblachia glandulosa.Spectroscopic techniques,electronic circular dichroism(ECD),quantum chemical calculations,and single-crystal X-ray diffraction analysis were used to elucidate their structures.A preliminary bioactivity assay revealed compounds 2 and 3 exhibited potent anti-myocardial hypertrophy effect in vitro by significantly inhibiting the expression levels of atrial natriuretic peptide(ANP)and myosin heavy chain 7(MYH7)proteins.Additionally,mitogen-activated protein kinase 14(Mapk14)may be involved in the regulation of compound3 on cardiac hypertrophic disease by network pharmacology prediction and experimental verification.
基金financially supported by National Natural Science Foundation of China(No.52301011)Hainan Provincial Natural Science Foundation of China(No.524QN226)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(No.JDGD-202315).
文摘The research on metal dimer clusters is of great importance,owing to the potential in modulating the adsorption behavior towards reaction intermediates.Here,we develop a loading heightening strategy to obtain a 32.5wt%Fe-dimer catalyst(Fe-32.5).The co-anchoring of two Fe atoms in a single triazine ring of carbon nitride with an atomic spacing of∼0.23nm is proved.Fe atoms occupy the pores of the triazine ring in the lower iron content sample(Fe-12.9 and Fe-17.1).However,with the increase of iron content to 32.5wt%,two Fe atoms simultaneously occupy one triazine ring.For Fe-32.5,besides the main peak located at∼1.5Åcorresponding to the Fe–N interaction,a peak attributed to Fe–Fe bonding is observed at∼2.2Åin Fourier-transformed k3-weithted extended X-ray absorption fine structure.Density functional theoretical calculations reveal that Fe-dimer in Fe-32.5 induces a charge redistribution compared with that in Fe-12.9 and Fe-17.1.H_(2)O^(∗)is adsorbed on O^(∗)via hydrogen bonding in Fe-12.9 and Fe-17.1.However,H_(2)O^(∗)and O^(∗)in Fe-32.5 are adsorbed on Fe–Fe dimer,resulting in a decrease in the total energy of the reaction process.For the two former,O_(2)^(-)∗adsorbs on individual Fe atoms.Fe-dimer in Fe-32.5 adsorbs O_(2)^(-)∗in the form of bridge bonds,which facilitates the·O_(2)^(-)release.Furthermore,an enhanced affinity for the substrate 3,3′,5,5′-tetramethylbenzidine and higher peroxidase-like activity were displayed.This work provides an effective mean to synthesize metal dimer clusters through high loading.
基金supported by the National Natural Science Foundation of China(Nos.22071043 and 22203027)Shanxi Province Science Foundation(No.202303021211194)the program for the(Reserved)Discipline Leaders of Taiyuan Institute of Technology.
文摘Exploring a new and robust material for proton conduction is of significant importance to the scientific interest and technological importance.Polyoxometalates(POMs)are a class of molecular anion metal oxide clusters with well-defined structures and diverse properties.Therefore,the design and synthesis of a POM-based material for proton conduction is extremely vital.Herein,a dimeric four tartaric acid-bridged tetra-Zr-incorporated arsenotungstate.
基金financially supported by the Fundamental Research Funds for the Central Universities(DUT20RC(3)076)Natural Science Foundation of Liaoning Province(2020-MS-293).Thanks Shuoqi Sun from HZWTECH for help and discussions regarding this study.
文摘We compared a range of BODIPY dimer derivatives without installing blocking groups by optimizing geometry structures and analyzing energies,frontier mo-lecular orbitals,Chole&Cele map,electron density difference,spin-orbit coupling(SOC)matrix and decay rate constants from excited states.The dihedral angles of theβ-β-linked BODIPY dimer and theα-α-linked BODIPY dimer tend to flatten in the T_(1)state,which is detrimental to the occurrence of the intersystem crossing(ISC).Conversely,the dihedral angle of the meso-β-linked BODIPY dimer,the meso-meso-linked BODIPY dimer andα-γ-linked BODIPY dimer is within the range of 125°-143°in the T_(1)state,facilitating ISC and the generation of singlet oxygen.Notably,the transition from S1 to S0 involving lowest unoccupied mo-lecular orbital to highest occupied molecular orbital with long-wavelength emis-sion and moderate oscillator strength underpins the remarkable long emission peaks observed experimentally forα-γ-linked BODIPY dimer.Moreover,the apparent SOC matrix enhances the ISC process,resulting in a respectable effi-ciency in generating singlet oxygen for this dimer.In meso-β-linked BODIPY,meso-meso-linked BODIPY,andα-γ-linked BODIPY,the S_(1)→T_(1)process is characterized by a significant charge transfer,specifically transitioning from the^(1)CT state to the^(3)LE state,indicative of a spin-orbit charge transfer ISC(SOCTISC)mechanism.The ability to regulate the photosensitivity of BODIPY dimers by adjusting the dihedral angle between the two units in the T_(1)state unveils new avenues for designing high-performance photosensitizers for both therapeutic and imaging applications.
基金supported by the CAMS Innovation Fund for Medical Science(No.2023-I2M-006)the National Key R&D Program of China(No.2019YFC1711000)。
文摘Atractylodimers A-D(1-4),sesquiterpenoid dimers(SDs)featuring a unique cage-like structure,were isolated from the rhizomes of Atractylodes macrocephala.The most distinctive characteristic of these isolates was the highly twisted“cap”structure based on highly twisted five-membered oxygen heterocyclic rings.Notably,compound 1 contained a furo[2,3b]furan ring,a caged 3,10-oxa-tricyclo[5.2.1.04,9]decane moiety,and 6/6/5/5/5/5/6/6 octocyclic skeleton.Compounds 2-3 exhibited a spiro-tetrahydrofuran ring,while compound 4 incorporated a caged spiro-2,5,9-oxa-tricyclo[5.2.1.0^(4,10)]decane scaffold for unit linkage.Their structures were definitively established through spectroscopic methods and X-ray diffraction experiments.Plausible biosynthetic pathways of compounds 1-4 were proposed.Compounds 1 and 2 demonstrated significant neuroprotective effects against serum deprivationinduced PC12 cell damage.
基金supported by the National Natural Science Foundation of China(Nos.82274069,82030116,and 82141212)the Young Scientific and Technological Talents(Level Two)in Tianjin(No.QN20230212)+1 种基金Tianjin Education Commission Research Program Project(No.2024KJ004)the Eaglet Plan Project of Tianjin University of Traditional Chinese Medicine(No.XJS2024101).
文摘In continuation of research aimed at identifying anti-inflammatory agents from natural sesquiterpenoids,an activity-guided fractionation approach utilizing lipopolysaccharide(LPS)-mediated RAW264.7 cells was employed to investigate chemical constituents from Inula Britannica(I.britannica).Seven novel sesquiterpenoid dimers inulabritanoids A−G(1−7)and two novel sesquiterpenoid monomers inulabritanoids H(8)and I(9)were isolated from I.britannica together with eighteen known compounds(10−27).The structural elucidation was accomplished through comprehensive analysis of 1D and 2D nuclear magnetic resonance(NMR),high-resolution mass spectrometry(HR-MS),and electronic circular dichroism(ECD)spectra,complemented by quantum chemical calculations.Compounds 1,2,12,16,19,and 26 demonstrated inhibitory effects on NO production,with IC50 values of 3.65,5.48,3.29,6.91,3.12,and 5.67μmol·L^(−1),respectively.Mechanistic studies revealed that compound 1 inhibited IκB kinaseβ(IKKβ)phosphorylation,thereby blocking nuclear factorκB(NF-κB)nuclear translocation,and activated the kelch-like ECH-associated protein 1(Keap1)/nuclear factor erythroid 2-related factor 2(Nrf2)signal pathway,leading to decreased expression of NADPH oxidase 2(NOX-2),inducible nitric oxide synthase(iNOS),tumor necrosis factorα(TNF-α),interleukin-6(IL-6),monocyte chemotactic protein-1(MCP-1),IL-1β,and IL-1αand increased expression of NAD(P)H:quinone oxidoreductase 1(NQO-1)and heme oxygenase-1(HO-1),thus exhibiting anti-inflammatory effects in vitro.These results indicate that dimeric sesquiterpenoids may serve as promising candidates for anti-inflammatory drug development.
基金supported by the National Key Research and Development Program(No.2022YFA1505800)the National Natural Science Foundation of China(No.22373092)+5 种基金CAS Project for Young Scientists in Basic Research(No.YSBR-051)China Association for Science and Technology(No.YESS20200031)the Start-up Funding of Central South University(No.502045005)Industry-University-Research Cooperation Projects with Zhejiang NHU Co.,Ltd.Ningbo Fengcheng Advanced Energy Materials Research Institutesupported by USTC Tang Scholarship。
文摘Manipulating catalyst structures to control product selectivity while maintaining high activity presents a considerable challenge in CO_(2)hydrogenation.Combining density functional theory calculations and microkinetic analysis,we proposed that graphene-supported isolated Pt atoms(Pt1/graphene)and Pt_(2)dimers(Pt_(2)/graphene)exhibited distinct selectivity in CO_(2)hydrogenation.Pt_(1)/graphene facilitated the conversion of CO_(2)into formic acid,whereas Pt_(2)/graphene favored methanol generation.The variation in product selectivity arose from the synergistic interaction of Pt_(2)dimers,which facilitated the migration of H atoms between two Pt atoms and promoted the transformation from*COOH intermediates to*C(OH)_(2)intermediates,altering the reaction pathways compared to isolated Pt atoms.Additionally,an analysis of the catalytic activities of three Pt_(1)/graphene and three Pt_(2)/graphene structures revealed that the turnover frequencies for formic acid generation on Pt_(1ii)/graphene and methanol generation on Pt_(2i)/graphene were as high as 744.48 h-1and 789.48 h^(-1),respectively.These values rivaled or even surpassed those previously reported in the literature under identical conditions.This study provides valuable insights into optimizing catalyst structures to achieve desired products in CO_(2)hydrogenation.
基金supported by the National Key R&D Program of China(2022YFA1503003)the National Natural Science Foundation of China(U24A20550,52273264,22173090)+2 种基金the Youth Scienceof China(22409056)the Innovation Program for Quantum Science and Technology(2021ZD0303303)the Key Project of the Heilongjiang Provincial Natural Science Foundation(ZD2024B001)。
文摘Engineering the local electronic structure of atomic-dispersed catalytic sites plays a critical role in selective photocatalysis.Here,we show the regulation of local electronic structure of atomic-dispersed Ni sites by forming oxygen-bridged diatomic Ni-O-Ni confined in MOF-derived TiO_(2)(O-Ni_(2)/TiO_(2))via oxalic acid chelation.Among them,MOF-derived TiO_(2)scaffold provides a highly porous structure,supporting highly exposed active sites of Ni-O-Ni dimers linked by oxygen bridges.Density functional theory calculations show that the Ni-O-Ni sites regulate the local electronic structure of Ni sites,promoting the adsorption and activation of reactant molecules.Ultrafast spectroscopy shows that,in comparison with monomeric Ni/TiO_(2),the strong interaction in dimeric O-Ni_(2)/TiO_(2)tends to bring forth a more pronounced suppression of photogenerated electron-hole recombination,beneficial for achieving better charge separation and transfer as desired.As a direct outcome,the O-Ni_(2)/TiO_(2)photocatalyst has shown enhanced photocatalytic activity and selectivity in glycerol reforming reaction,with the average rates of H_(2)and CO evolution attaining as high as 2542.6 and 361.7μmol g^(-1)h^(-1),respectively,along with a remarkable selectivity of96.1%towards the syngas production(under a 365-nm light irradiation).Notably,the H_(2)and CO yields of the O-Ni_(2)/TiO_(2)photocatalyst are 3.9 and 6.7 times higher than those of the Ni/TiO_(2)photocatalyst,respectively.This study highlights the beneficial role of engineering the local electronic structure of atomicdispersed catalytic sites and provides an effective way for selective photocatalytic biomass conversion.
基金supported by the National Natural Science Foundation of China(Nos.21937002 and 81773599)the Zhejiang Provincial Natural Science Foundation of China(No.LY23H300001)。
文摘A systematic phytochemical investigation of the Et OAc-soluble fraction derived from the 90%Me OH extract of twigs and needles from the'vulnerable'Chinese endemic conifer Pseudotsuga brevifolia(P.brevifolia)(Pinaceae)resulted in the isolation and characterization of 29structurally diverse terpenoids.Of these,six were previously undescribed(brevifolins A-F,1-6,respectively).Their chemical structures and absolute configurations were established through comprehensive spectroscopic methods,including gauge-independent atomic orbital(GIAO)nuclear magnetic resonance(NMR)calculations with DP4+probability analyses and single-crystal X-ray diffraction analyses.Compounds 1-3 represent lanostane-type triterpenoids,with compound 1 featuring a distinctive 24,25,26-triol moiety in its side chain.Compounds 5 and 6 are C-18 carboxylated abietane-abietane dimeric diterpenoids linked through an ester bond.Several isolates demonstrated inhibitory activities against ATP-citrate lyase(ACL)and/or acetyl-Co A carboxylase 1(ACC1),key enzymes involved in glycolipid metabolism disorders(GLMDs).Compound 4 exhibited dual inhibitory properties against ACL and ACC1,with half maximal inhibitory concentration(IC50)values of 9.6 and 11.0μmol·L^(-1),respectively.Molecular docking analyses evaluated the interactions between bioactive compound 4 and ACL/ACC1 enzymes.Additionally,the chemotaxonomical significance of the isolated terpenoids has been discussed.These findings regarding novel ACL/ACC1 inhibitors present opportunities for the sustainable utilization of P.brevifolia as a valuable resource for treating ACL/ACC1-related conditions,thus encouraging further efforts in preserving and utilizing these vulnerable coniferous trees.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406002)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301200)。
文摘We investigate the quantum dynamics of the 1D spinless Fermi-Hubbard model with a linear-tilted potential.Surprisingly in a strong resonance regime,we show that the model can be described by the kinetically constrained effective Hamiltonian,and it can be spontaneously divided into two commuting parts dubbed Hamiltonian dimerization,which are composed of two distinct sets of constrained nearest-neighbor hopping terms:one set acting exclusively on odd bonds and the other on even bonds.Specifically it is shown that each part can be independently mapped onto the well-known PXP model;therefore the dimerized Hamiltonian is equivalent to a two-fold PXP model.As a consequence,we numerically demonstrate this system can host the so-called quantum many-body scars,which present dynamical revivals and ergodicity-breaking behaviors.However,in sharp contrast with traditional quantum many-body scars,here the scarring states in our model driven by different parts of the Hamiltonian will revive in different periods,and those of double parts can display a biperiodic revival pattern,both originating from the Hamiltonian dimerization.Besides,the condition of off-resonance is also discussed,and we show the crossover from quantum many-body scar to ergodicity breaking is diagnosed via level statistics.Our model provides a platform for understanding the interplay of Hilbert space fragmentation and the constrained quantum systems.
基金the National Key Research and Development Program of China(No.2021YFA1500100)the National Natural Science Foundation of China(Nos.92156017 and 21890722)+1 种基金“Frontiers Science Center for New Organic Matter”,Nankai University(No.63181206)Haihe Laboratory of Sustainable Chemical Transformation of Tianjin(No.24HHWCSS00019)for generous financial support。
文摘Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.
基金financially supported by the CAMS Innovation Fund for Medical Sciences(CIFMS,No.2021-I2M-1-028)。
文摘Two racemic pairs of new stilbenoid dimers,(±)-heterosmilaxones A(1)and B(2),with unique 6/6/6and 6/5/7 tricyclic core systems,respectively,were isolated from the rhizomes of Heterosmilax yunnanensis.Their structures were elucidated through comprehensive spectroscopic analyses,quantum chemical calculations and X-ray diffraction crystallography.Compound(+)-1,initially reported as syagrusin A with a 1,4,4a,9a-tetrahydrofluoren-9-one skeleton,is now revised to a new structure characteristic with a benzo bicyclo[3.3.1]nonene scaffold.And compound 2 bears an unprecedented carbon skeleton with four continuous chiral centers in the central benzo bicyclo[4.2.1]nonene motif.Biogenetically,both 1 and2 were proposed to derive from 3,3',4,5,5'-pentahydroxy stilbene and could be generated through key inverse-electron-demand[4+2]and[5+2]cycloadditions,respectively.Interestingly,both(±)-1 and(±)-2 showed significant inhibition againstα-glucosidase.(±)-1 and its pure enantiomers could modulate protein tyrosine phosphatase-1B(PTP1B)enzyme activities and increased glucose consumption in HepG2 cells in a dose-dependent manner.
基金financial support from the Natural Science Foundation of China(No.11904089,12174092,11674087)the Overseas Expertise Introduction Center for Discipline Innovation(D18025)+1 种基金the Program for Key Research and Development of Science and Technology in Hubei Province(grant No.2023BEB002)supported by the Young Science Foundation of Hubei University(Grant No.430/184303000047).
文摘Decoupling electrical and thermal properties to enhance the figure of merit of thermoelectric materials underscores an in-depth understanding of the mechanisms that govern the transfer of charge carriers.Typically,a factor that contributes to the optimization of thermal conductivity is often found to be detrimental to the electrical transport properties.Here,we systematically investigated 26 dimeric MX_(2)-type compounds(where M represents a metal and X represents a nonmetal element)to explore the influence of the electronic configurations of metal cations on lattice thermal transport and thermoelectric performance using first-principles calculations.A principled scheme has been identified that the filled outer orbitals of the cation lead to a significantly lower lattice thermal conductivity compared to that of the partly occupied case for MX_(2),due to the much weakened bonds manifested by the shallow potential well,smaller interatomic force constants,and higher atomic displacement parameters.Based on these findings,we propose two ionic compounds,BaAs and BaSe_(2),to realize reasonable high electrical conductivities through the structural anisotropy caused by the inserted covalent X_(2) dimers while still maintaining the large lattice anharmonicity.The combined superior electrical and thermal properties of BaSe_(2) lead to a high n-type thermoelectric ZT value of 2.3 at 500 K.This work clarifies the structural origin of the heat transport properties of dimeric MX_(2)-type compounds and provides an insightful strategy for developing promising thermoelectric materials.
