Centaurium erythraea Rafn(“Gosset El Haya”)has long been prized in North African folk medicine,yet Moroccan chemobiological data remain scarce.Ethanol extracts of northern Moroccan aerial parts were profiled by high...Centaurium erythraea Rafn(“Gosset El Haya”)has long been prized in North African folk medicine,yet Moroccan chemobiological data remain scarce.Ethanol extracts of northern Moroccan aerial parts were profiled by high-performance liquid chromatography(HPLC)and found rich in phenolics,dominated by 4-hydroxybenzoic acid(57.8%)and naringin(10.3%).The extract exhibited strong antioxidant power in the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical-scavenging assay,with a half-maximal inhibitory concentration(IC_(50))of≈74μg mL^(−1),and a total antioxidant capacity(TAC)of≈201μg mL^(−1)and selective antimicrobial activity,sharply inhibiting Aspergillus niger,Penicillium digitatum,and Rhodotorula glutinis while sparing Staphylococcus aureus.In-silico absorption,distribution,metabolism,excretion,and toxicity(ADMET)profiling predicted good oral bioavailability for low-molecular-weight acids and aglycones,lowtoxicity across all metabolites,but absorption liabilities for bulky glycosides.Molecular docking against A.niger esterase(1UKC),C.glabrata lanosterol 14-α-demethylase CYP51(5JLC),and P.digitatum ethyleneforming oxidoreductase(9EIR)corroborated bioassays:rutin and naringin bound more tightly than fluconazole(ΔG≈−9.1 to−10.0 kcal mol^(−1)),whereas quercetin and catechin offered balanced affinity pharmacokinetic profiles.Robust radical scavenging,targeted antifungal potency,and favorable in-silico pharmacokinetics thus position Moroccan C.erythraea as a promising,though standardization-dependent,source of nutraceutical,medicinal,and food-preservation agents.These results support the valorisation of Centaurium erythraea as a promising source for health promotion and green technology applications through its antioxidant,antimicrobial,and drug-like properties.展开更多
Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has ...Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.展开更多
Thymus serpyllum L.,often known as wild thyme,has been used since ancient times due to its multifaceted culinary and medicinal attributes.It is usually utilized in folk medicine to manage different health issues.This ...Thymus serpyllum L.,often known as wild thyme,has been used since ancient times due to its multifaceted culinary and medicinal attributes.It is usually utilized in folk medicine to manage different health issues.This work aimed to investigate the chemical composition and biological characteristics of T.serpyllum essential oil(EO),including its antimicrobial,antioxidant,and anti-inflammatory capabilities.Moreover,we have prompted an in-silico simulation to reveal the underlying mode of action of these properties.The chemical characterization of T.serpyllum(EO)by Gas Chromatography-Mass Spectrometry(GC-MS)indicated sabinene(17.33%),terpinen-4-ol(11.73%),phellandral(13.18%),and thymol(10.54%)as main components.The antimicrobial screening utilized the disc-diffusion technique,MIC,and MBC assays.The disc-diffusion test’s results revealed significant anti-Candida activity and notable antibacterial efficacy.The MIC and MBC tests showed that T.serpyllum EO effectively stops bacterial growth,including Gram-positive and Gram-negative strains and Candida strains.The tolerance level ratio demonstrated that this EO exhibits bactericidal and fungicidal effects on all tested bacteria and Candida strains.Also,T.serpyllum EO presented effective inhibitory activity against the 5-lipoxygenase(5-LOX)enzyme(IC50=744.19±0.1µg/mL)(p<0.05).It also effectively affected FRAP,β-carotene,DPPH,and ABTS radicals.In light of these findings,T.serpyllum holds promise for diverse applications across pharmaceuticals,nutraceuticals,and the food industry.However,further research and collaboration between traditional knowledge and modern medicine are crucial to fully realizing its potential benefits in these fields.展开更多
In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented...In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.展开更多
A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quino...A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.展开更多
Under solvothermal conditions,1,4‑naphthalenedicarboxylic acid(H_(2)ndc)and 9,9′‑dihexyl‑2,7‑di(pyridin‑4‑yl)fluorene(hfdp)reacted with Co^(2+)ions and Cd^(2+)ions to form two coordination polymers,[Co(hfdp)(ndc)(H2O...Under solvothermal conditions,1,4‑naphthalenedicarboxylic acid(H_(2)ndc)and 9,9′‑dihexyl‑2,7‑di(pyridin‑4‑yl)fluorene(hfdp)reacted with Co^(2+)ions and Cd^(2+)ions to form two coordination polymers,[Co(hfdp)(ndc)(H2O)]·DMA}n(1)and{[Cd(hfdp)(ndc)(H_(2)O)]·DMA}_(n)(2),respectively(DMA=N,N‑dimethylacetamide).Single‑crystal X‑ray diffraction analyses showed that both complexes 1 and 2 contain similar structures.Topological analysis indicates that complexes 1 and 2 have a{44·62}planar structure.In addition,both complexes reveal good thermal stability and fluorescence sensing performance.They exhibited good sensitivity and selectivity towards 2,4,6‑trinitrophenol(TNP)by fluorescent quenching.The limits of detection of 1 and 2 for TNP were 0.107 and 0.327μmol·L^(-1),respectively.CCDC:2475515,1;2475516,2.展开更多
The morphology of active layer plays a critical role in determining the photovoltaic performance of organic solar cells(OSCs).However,binary blends often suffer from suboptimal phase separation,which limits the effici...The morphology of active layer plays a critical role in determining the photovoltaic performance of organic solar cells(OSCs).However,binary blends often suffer from suboptimal phase separation,which limits the efficiency of OSCs.Herein,two bridging polymer acceptors(PAs)—benzodithiophene-(2-ethylhexyl)oxy(BDT-C2C4)and benzodithiophene-octyloxy(BDT-C_(8))—are designed and synthesized by combining a benzodithiophene(BDT)unit as the donor moiety[poly({4,8-bis[5-(2-ethylhexyl)-4-fluorothiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}){5,8-bis[4-(2-butyloctyl)thiophen-2-yl]dithieno[3',2':3,4]},D18],and a 2,2′-((2Z,2′Z)-{[12,13-Bis(2-butyloctyl)-12,13-dihydro-3,9-dinonylthieno[2,3]thieno[3,2-b]pyrrolo[4,5-g]thieno[2,3-b]indole-2,10-diyl]bis(methanylylidene)}bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(Y6)derivative as the acceptor moiety.BDT-C2C4 and BDT-C_(8) are functionalized with(2-ethylhexyl)oxy and octyloxy side chains on the BDT unit,respectively.Both PAs show complementary absorption and cascaded energy levels with the donor D18 and the acceptor 2,2′-((2Z,2′Z)-{[12,13-bis(3-ethylheptyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3″∶4′,5′]thieno[2′,3′∶4,5]pyrrolo[3,2-g]thieno[2′,3′∶4,5]thieno[3,2-b]indole-2,10-diyl]bis(meth⁃aneylylidene)}bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(N3),but BDT-C_(8) exhibits better compatibility with D18 and N3 compared to BDT-C2C4.When incorporated as a third component into the D18∶N3 blend,both PAs improve the active layer morphology.In particular,the D18∶N3∶BDT-C_(8) blend shows significantly optimized morphology,featuring reduced phase separation and a fibrous network structure.As a result,the device based on D18∶N3∶BDT-C_(8) achieves a power conversion efficiency of 18.18%,significantly higher than that of the device based on D18∶N3(ca.17.37%).This work presents a compatibilizer strategy for optimizing blend morphology towards high-performance ternary OSCs.展开更多
Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on lo...Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on low-toxicity tetravalent platinum(Pt(Ⅳ))com plexes holds substantial research value.Herein,we discovered that coumarin derivatives exhibit inherent antitumor efficacy and significantly enhance superoxide anion radicals(·O_(2)^(-))generation in aqueous solutions under ultrasound(US)irradiation.Given that·O_(2)^(-)is known to mediate the reduction of Pt(Ⅳ)to divalent platinum(Pt(Ⅱ)),we engineered an US-responsive dual-drug nanoprodrug(P-cisPt(Ⅳ)@5-MOP).This nanoprodrug was prepared by covalently conjugating Pt(Ⅳ)and methoxy polyethylene glycol hydroxyl(m PEG-OH)to a poly(_(L)-glutamic acid)(PLG)carrier,followed by encapsulating coumarin derivatives.Under low-intensity US irradiation(1.5 W/cm^(2),1 MHz,10 min),P-cisPt(Ⅳ)@5-MOP achieved a Pt(Ⅳ)reduction rate of 91.4%.Furthermore,upon US exposure,its half-maximal inhibitory concentration(IC_(50))against 4T1 breast cancer cells decreased dramatically from 25.7μmol/L to 0.1μmol/L.Remarkably,this system combined with US therapy yielded a tumor inhibition rate of 90.9%,with 40%of tumor-bea ring mice achieving com plete eradication of tumors,while exhibiting low systemic toxicity.Collectively,this work not only identifies a novel sonosensitizer capable of generating·O_(2)^(-)but also develops a new class of ultrasound-activatable Pt(Ⅳ)nanoprodrug.展开更多
D-π hybridization is a key structural feature that may significantly affect the intrinsic electronic properties of metallopolymers.Herein,we present the electrosynthesis and memristive properties of metallopolymers u...D-π hybridization is a key structural feature that may significantly affect the intrinsic electronic properties of metallopolymers.Herein,we present the electrosynthesis and memristive properties of metallopolymers using the distinct d-π hybridization monomers R_(1) and R_(2).R_(1)(Ru^(Ⅱ)-(tpz)Cl_(2))features tetradentate ligands(tpz,6,6'-di(1H-pyrazol-1-yl)-2,2'-bipyridine)enforcing quasi-octahedral geometry;R_(2)(Ru^(Ⅱ)-(bpp)_(2))incorporates tridentate ligands(bpp,2,6-di(1H-pyrazol-1-yl)pyridine)inducing pronounced geometric distortion.The planar ligand(tpz)in R_(1) facilitates ordered molecular assembly through high conformational rigidity and extensive π-π stacking,resulting in increased molecular densities and enhanced morphological uniformity compared to R_(2) metallopolymers.Due to pyrazole’s weaker π-acceptance and strongerσ-donation compared to pyridine,R_(1) exhibits a 119 nm red-shift in metal-to-ligand charge transfer(MLCT)band and a 30 mV anodic shift in Ru^(+2/+3)redox potential relative to R_(2).Coupled with a reduced HOMO-LUMO gap,the uniform and ordered structure leads to a lower conductance decay constant in R_(1).Additionally,R_(2) metallopolymers exhibit superior memristive performance(characterized by lower switching voltage and higher switching ratio)via redox-induced aromatic transitions in axial ligands enhancing electronic delocalization.This work compares two metallopolymers with different ligand geometries,revealing how this difference leads to distinct charge transport and memristive behaviors.展开更多
Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catal...Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catalysts,but which substantially involve multi-step,tedious,and difficult synthesis.Herein,this study reports an intriguing approach to construct multi-nuclear catalysts for the milestoneα-diimine nickel catalysts using an oligomeric strategy.A polymerizable norbornene unit is incorporated into theα-diimine ligand backbone,leading to the formation of the monomeric nickel catalyst Ni_(1)and its corresponding oligomeric nickel catalysts(Ni_(3)and Ni_(5))with varying degrees of polymerization(DP=3 and 5).Notably,the oligomeric catalyst Ni_(5)was facilely scaled up(50 g-level),showed enhanced thermal stability,exhibited 4.6 times higher activity,and yielded polyethylene elastomer with a 379%increased molecular weight in ethylene polymerization,compared to the monomeric catalyst Ni_(1).Catalytic performance enhancements of oligomeric catalysts were found to be DP-dependent.The kilogram-scale polyethylene,produced using Ni_(5)in a 20 L reactor,presented a highly branched all-hydrocarbon structure,which demonstrated typical elastic properties(tensile strength:4 MPa,elastic recovery:SR=72%)along with great processability(MFI=3.0 g/10 min),insulating characteristics(volume resistivity=2×10^(16)Ω/m),and hydrophobicity(water vapor permeability:0.03 g/m^(2)/day),suggesting potentially practical applications.展开更多
Addiction,a complex and chronic neurobiological disorder,is characterized by compulsive substance use despite harmful consequences,leading to persistent alterations in brain function,particularly within the reward,mot...Addiction,a complex and chronic neurobiological disorder,is characterized by compulsive substance use despite harmful consequences,leading to persistent alterations in brain function,particularly within the reward,motivation,and decision-making systems.Despite the availability of a range of treatment options,including pharmacotherapy and behavioral therapies,relapse remains a major challenge,with many individuals struggling to maintain long-term recovery.Current treatments often show limited efficacy,underscoring the need for novel therapeutic strategies that can address the underlying neurobiological disruptions in addiction.展开更多
Pure organic room-temperature phosphorescent(RTP)polymers possess good processability and flexibility over small molecular crystals.However,most of RTP polymers reported so far are based on non-conjugated polymers,and...Pure organic room-temperature phosphorescent(RTP)polymers possess good processability and flexibility over small molecular crystals.However,most of RTP polymers reported so far are based on non-conjugated polymers,and achieving efficient phosphorescent emission in RTP conjugated polymers(CPs)remains a significant challenge.Herein,we developed two RTP CPs(P(PSe ZPh-p-Ph)and P(PSe ZPh-m-Ph))by linking the phenoselenazine units with the para-and meta-phenylene units,respectively,to form the conjugated main chains.The phenylene linker with different lingking mode manipulates the effictiveπ-conjugation of the polymer backbones.Comparing with the para-linked P(PSe ZPh-pPh),meta-linked P(PSe ZPh-m-Ph)exhibit the decreased effectiveπ-conjugation and the enhanced contribution of selenium atoms to the frontier orbitals,leading to the larger spin-orbit coupling(SOC)constants and the accelerated phosphorescence radiative decay process.The P(PSe ZPhm-Ph)achieves a phosphorescence quantum yield of 21.4%in doped polystyrene films,which is among the highest efficiencies reported to date for pure organic RTP CPs.These CPs are applied to construct phosphorescent film sensors for oxygen detection with the high quenching constants(K_(sv))up to 14.80 kPa^(-1)and low detection of limit of 0.84 ppm,demostrating the potential for application in oxygen film sensors.展开更多
This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. Th...This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.展开更多
Albeit notable endeavors in the construction of organophosphorodithioates,the direct catalytic enantioselective synthesis of organophosphorodithioates still stands for a long-lasting challenge.Herein,an efficient orga...Albeit notable endeavors in the construction of organophosphorodithioates,the direct catalytic enantioselective synthesis of organophosphorodithioates still stands for a long-lasting challenge.Herein,an efficient organocatalytic enantioselective nucleophilic addition of vinylidene ortho-quinone methide with phosphinothioic thioanhydride as nucleophilic reagent has been achieved by the dual catalysis of cinchona alkaloid-derived squaramide and 4-dimethylaminopyridine.This protocol provides a straightforward approach for accessing a variety of axially chiral phosphorodithiolated styrenes in good yields(up to 98 %yield) with high stereoselectivities(up to 97 % ee and >99:1 E/Z).展开更多
The heterogeneity and invasiveness of cancer cells pose serious challenges in cancer diagnosis and treatment.Advancements and innovations in metal-based nanomedicines provide novel avenues for addressing these challen...The heterogeneity and invasiveness of cancer cells pose serious challenges in cancer diagnosis and treatment.Advancements and innovations in metal-based nanomedicines provide novel avenues for addressing these challenges.Metal-based nanomedicines possess unique physicochemical properties that enable their interaction with living organisms,thereby inducing complex biological responses.These nanomaterials have been extensively used to enhance the contrast and sensitivity of cancer imaging and to amplify the distinction between cancerous and healthy tissues.Moreover,these nanomaterials can effectively combat a wide spectrum of cancers through various methods,including drug delivery,radiotherapy,photothermal therapy(PTT),photodynamic therapy(PDT),sonodynamic therapy(SDT),biocatalytic therapy,ion interference therapy(IIT),and immunotherapy.Currently,there is still a need for a comprehensive summary on the metal-based nanomaterials for cancer diagnosis and treatment.Herein,we present a systematic and complete overview of action mechanisms and the applications of metal-based nanomaterials in cancer theranostics.A summary of common strategies for synthesizing and modifying metal-based nanomedicines is presented,and their biosafety is analyzed.Then,the latest developments in their applications for cancer imaging and anticancer treatment are provided.Finally,the key technical challenges and reasonable perspectives of metal-based nanomedicines for cancer theranostics in clinical applications are discussed.展开更多
A polylactide(PLA)blend with simultaneous enhancement of strength,toughness,and heat resistance was successfully achieved by adding biodegradable poly(propylene carbonate)(PPC)and uniaxial pre-stretching.The effects o...A polylactide(PLA)blend with simultaneous enhancement of strength,toughness,and heat resistance was successfully achieved by adding biodegradable poly(propylene carbonate)(PPC)and uniaxial pre-stretching.The effects of the PPC content(0 wt%-50 wt%)on the phase morphology and performance of the blends before and after pre-stretching were systematically investigated.Blending PPC initially reduced the strength,modulus,and heat resistance,but pre-stretching significantly enhanced these properties.In blends containing≤30 wt%PPC,where PPC formed a well-dispersed island-like phase within the PLA matrix,pre-stretching simultaneously enhanced strength,toughness,and heat resistance.The optimized pre-stretched 70/30 PLA/PPC(ps-70/30)blend achieved exceptional performance:tensile strength increased from 66.9MPa to 84.5 MPa,elongation at break dramatically improved from 6.8%to 115.1%,impact strength reached 55.1 k J/m^(2)(far exceeding neat PLA's 3.5 k J/m^(2)),and Vicat softening temperature(VST)increased by 60.6%to 101.8℃.Notably,the ps-70/30 blend retained excellent mechanical properties even after six months of aging.These improvements were attributed to the synergistic effects of the PPC incorporation and prestretching.PPC not only promoted the high orientation of the PLA molecular chains but also facilitated the formation of a stable crystalline phase during pre-stretching,thereby enhancing both the mechanical properties and heat resistance.However,when the PPC content exceeded 30wt%,phase inversion occurred,resulting in a continuous amorphous PPC phase that degraded the overall performance.This study demonstrated that a combination of controlled PPC incorporation and pre-stretching can effectively overcome PLA's brittleness of PLA while improving its heat resistance,offering a promising strategy for developing high-performance,fully biodegradable PLA materials suitable for industrial applications.展开更多
The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav...The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.展开更多
Cyclic olefin copolymers(COCs)are highly valuable optical resins,but their productions on industry are fully limited by the monomer norbornene.Although ethylene/dicyclopentadiene(E/DCPD)copolymers provide a cost-effec...Cyclic olefin copolymers(COCs)are highly valuable optical resins,but their productions on industry are fully limited by the monomer norbornene.Although ethylene/dicyclopentadiene(E/DCPD)copolymers provide a cost-effective alternative to commercially available COCs because of using low-cost DCPD as cyclic olefin monomer,these inherent unsaturated double bonds on E/DCPD copolymers cause low heat resistance,oxidation,and crosslinking during processing and storage.And E/DCPD copolymers usually showed lower glass-transition temperature(T_(g))compared with commercially available COCs.In this study,we studied the E-DCPD copolymerization catalyzed by a scandium complex and the sequential hydrogenation catalyzed by a nickel compound to prepare saturated copolymers H-(E/DCPD).The polymerization activities are high up to 5.86×10^(6)g/(molSc·h),and the resultant H-(E/DCPD)copolymers showed narrow polymer dispersity index(PDI=1.5–2.0).By changing the polymerization conditions,a series of H-(E/DCPD)copolymers with tunable DCPD incorporation(28.4 mol%–44.9 mol%)and a wide range of T_(g)(123–171°C)were obtained.H-(E/DCPD)copolymers exhibited excellent optical properties(transparency>90%,refractive index of 1.543),similar to those of commercial COCs,making them an alternative for high-performance optical applications.This method solves the problems of traditional E/DCPD copolymers and provides a practical way to produce stable and low-cost COCs,and is comparable with commercially available COC resins.展开更多
The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it t...The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it to polymer segmental motion.In this study,a low-content ionic plasticizer additive1-butyl-3-dimethylimidazolium bromide(BMImBr)was introduced into the PVDF-HFP/LiTFSI/DMF matrix to modulate the Li^(+)solvation environment.Unlike conventional dual-salt systems,the introduced Br-anions dynamically compete for Li^(+)coordination,disrupting the rigid Li^(+)-TFSI^(-)/DMF solvation shell and constructing a"statistically labile and diffuse ionic cloud"characterized by reduced coordination numbers,weakened binding energies,and a more diffuse electrostatic potential landscape.This restructured solvation environment facilitates partially decoupled Li^(+)transport,as evidenced by dielectric spectroscopy and molecular dynamics simulations.Furthermore,the in situ formation of a LiBr-rich solid electrolyte interphase(SEI)effectively stabilizes the Li-metal interface and significantly reduces interfacial resistance.As a result,the optimized polymer electrolyte delivers outstanding electrochemical performance,achieving a high ionic conductivity of 0.8×10^(-4) S/cm,ultra-stable symmetric cell cycling over 500 h,and superior capacity retention exceeding 94%after 150 cycles at 0.5 C.This study elucidates a dynamic ion transport mechanism driven by competitive anion coordination and provides a viable strategy for simultaneously addressing the conductivity-stability trade-off in solid-state lithium metal batteries.展开更多
Vanadium-based materials have emerged as promising cathode candidates for aqueous zinc-ion batteries(AZIBs)due to their multivalent redox characteristics and diverse crystal structures,which enable high energy storage...Vanadium-based materials have emerged as promising cathode candidates for aqueous zinc-ion batteries(AZIBs)due to their multivalent redox characteristics and diverse crystal structures,which enable high energy storage capacity.Nevertheless,practical applications are hindered by several critical challenges,including vanadium species dissolution,side-product formation,sluggish Zn^(2+)diffusion kinetics,and low electrical conductivity.Organic functionalization,benefiting from its structural tunability and abundant functional groups,has been proven to be an effective strategy for enhancing the electrochemical performance of vanadium-based cathodes.This review systematically summarizes recent advances in organic-functionalized vanadium-based cathodes.First,the energy storage mechanism of vanadiumbased cathodes and the fundamental properties of organic compounds relevant to cathode optimization are outlined.Then,the functions of organic compounds are comprehensively analyzed from four key perspectives:capacity improvement,conductivity enhancement,Zn^(2+)diffusion kinetics optimization,and cycling stability promotion.Furthermore,the specific electrochemical performance modulation effects and practical application examples of this strategy are discussed in detail.Finally,current limitations and challenges in this field are highlighted,and corresponding solutions and future research directions are proposed,offering theoretical guidance and insights for the development of high-performance vanadium-based cathodes for AZIBs.展开更多
文摘Centaurium erythraea Rafn(“Gosset El Haya”)has long been prized in North African folk medicine,yet Moroccan chemobiological data remain scarce.Ethanol extracts of northern Moroccan aerial parts were profiled by high-performance liquid chromatography(HPLC)and found rich in phenolics,dominated by 4-hydroxybenzoic acid(57.8%)and naringin(10.3%).The extract exhibited strong antioxidant power in the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical-scavenging assay,with a half-maximal inhibitory concentration(IC_(50))of≈74μg mL^(−1),and a total antioxidant capacity(TAC)of≈201μg mL^(−1)and selective antimicrobial activity,sharply inhibiting Aspergillus niger,Penicillium digitatum,and Rhodotorula glutinis while sparing Staphylococcus aureus.In-silico absorption,distribution,metabolism,excretion,and toxicity(ADMET)profiling predicted good oral bioavailability for low-molecular-weight acids and aglycones,lowtoxicity across all metabolites,but absorption liabilities for bulky glycosides.Molecular docking against A.niger esterase(1UKC),C.glabrata lanosterol 14-α-demethylase CYP51(5JLC),and P.digitatum ethyleneforming oxidoreductase(9EIR)corroborated bioassays:rutin and naringin bound more tightly than fluconazole(ΔG≈−9.1 to−10.0 kcal mol^(−1)),whereas quercetin and catechin offered balanced affinity pharmacokinetic profiles.Robust radical scavenging,targeted antifungal potency,and favorable in-silico pharmacokinetics thus position Moroccan C.erythraea as a promising,though standardization-dependent,source of nutraceutical,medicinal,and food-preservation agents.These results support the valorisation of Centaurium erythraea as a promising source for health promotion and green technology applications through its antioxidant,antimicrobial,and drug-like properties.
基金funded by the National Key R&D Program of China(2021YFA1501101)the National Natural Science Foundation of China(No.22471103,22425105,22201111,21931001,22221001,and 22271124)+5 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04)the 111 Project(B20027)as well as the National Natural Science Foundation of Gansu Province(22JR5RA470)the Fundamental Research Funds for the Central Universities(lzujbky-2023-eyt03)supported by the Agency for Science,Technology and Research(A*STAR)MTC Individual Research Grants(IRG)M22K2c0078.
文摘Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution reaction.The surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity enhancement.Here,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is reported.The substituting Fe content influences both current change tendency and surface reconstruction degree.LaNi_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)series.The reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based catalysts.Besides,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term stability.Furthermore,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction degree.The effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface reconstruction.This finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.
文摘Thymus serpyllum L.,often known as wild thyme,has been used since ancient times due to its multifaceted culinary and medicinal attributes.It is usually utilized in folk medicine to manage different health issues.This work aimed to investigate the chemical composition and biological characteristics of T.serpyllum essential oil(EO),including its antimicrobial,antioxidant,and anti-inflammatory capabilities.Moreover,we have prompted an in-silico simulation to reveal the underlying mode of action of these properties.The chemical characterization of T.serpyllum(EO)by Gas Chromatography-Mass Spectrometry(GC-MS)indicated sabinene(17.33%),terpinen-4-ol(11.73%),phellandral(13.18%),and thymol(10.54%)as main components.The antimicrobial screening utilized the disc-diffusion technique,MIC,and MBC assays.The disc-diffusion test’s results revealed significant anti-Candida activity and notable antibacterial efficacy.The MIC and MBC tests showed that T.serpyllum EO effectively stops bacterial growth,including Gram-positive and Gram-negative strains and Candida strains.The tolerance level ratio demonstrated that this EO exhibits bactericidal and fungicidal effects on all tested bacteria and Candida strains.Also,T.serpyllum EO presented effective inhibitory activity against the 5-lipoxygenase(5-LOX)enzyme(IC50=744.19±0.1µg/mL)(p<0.05).It also effectively affected FRAP,β-carotene,DPPH,and ABTS radicals.In light of these findings,T.serpyllum holds promise for diverse applications across pharmaceuticals,nutraceuticals,and the food industry.However,further research and collaboration between traditional knowledge and modern medicine are crucial to fully realizing its potential benefits in these fields.
基金Supported by the National Key Research and Development Program of Traditional Chinese Medicine Modernization Project,China(No.2023YFC3504000)the Science and Technology Development Project of Jilin Province,China(No.20240404043ZP)the Science and Technology Innovation Cooperation Project of Changchun Science and Technology Bureau and Chinese Academy of Sciences,China(No.23SH14)。
文摘In this study,a novel polysaccharide GPA-G 2-H was derived from ginseng.Furthermore,the coherent study of its structural characteristics,fermented characteristics in vitro,as well as antioxidant mechanism of fermented product FGPA-G 2-H on Aβ25-35-induced PC 12 cells were explored.The structure of GPA-G 2-H was determined by means of zeta potential analysis,FTIR,HPLC,XRD,GC-MS and NMR.The backbone of GPA-G 2-H was mainly composed of→4)-α-D-Glcp-(1→with branches substituted at O-3.Notably,GPA-G 2-H was degraded by intestinal microbiota in vitro with total sugar content and pH value decreasing,and short-chain fatty acids(SCFAs)increasing.Moreover,GPA-G 2-H significantly promoted the proliferation of Lactobacillus,Muribaculaceae and Weissella,thereby making positive alterations in intestinal microbiota composition.Additionally,FGPA-G 2-H activated the Nrf 2/HO-1 signaling pathway,enhanced HO-1,NQO 1,SOD and GSH-Px,while inhabited Keap 1,MDA and LDH,which alleviated Aβ-induced oxidative stress in PC 12 cells.These provide a solid theoretical basis for the further development of ginseng polysaccharides as functional food and antioxidant drugs.
文摘A detailed investigation was carried out to understand how the variations in configurations of the spiroannulated 6-6-6-5-5 pentacyclic diastereoisomers,the key intermediates for the synthesis of two C30 terpene quinonemethides and their stereoisomers,impact the reactivity of cyclopropanation.The configurations at C9,C8,and C14 for all four pentacyclic diastereoisomers involved in the diastereoisomeric mixture were determined through a combination of suitable chemical derivatization and multiple NMR spectroscopic analyses.Based on the defined configuration,the 3D structures of these diastereoisomers were optimized by density functional theory(DFT)calculation.These investigations provide reasonable supports,mainly from the steric considerations,for understanding why different diastereoisomers exhibit markedly different reactivity,as well as regio-and stereo-selectivity for cyclopropanation.In addition,the mechanism for the construction of the spiroannulated 6-6-6-5-5 pentacyclic scaffold via intramolecular Michael/aldol cascade was also investigated by deuterium labeling experiments.
文摘Under solvothermal conditions,1,4‑naphthalenedicarboxylic acid(H_(2)ndc)and 9,9′‑dihexyl‑2,7‑di(pyridin‑4‑yl)fluorene(hfdp)reacted with Co^(2+)ions and Cd^(2+)ions to form two coordination polymers,[Co(hfdp)(ndc)(H2O)]·DMA}n(1)and{[Cd(hfdp)(ndc)(H_(2)O)]·DMA}_(n)(2),respectively(DMA=N,N‑dimethylacetamide).Single‑crystal X‑ray diffraction analyses showed that both complexes 1 and 2 contain similar structures.Topological analysis indicates that complexes 1 and 2 have a{44·62}planar structure.In addition,both complexes reveal good thermal stability and fluorescence sensing performance.They exhibited good sensitivity and selectivity towards 2,4,6‑trinitrophenol(TNP)by fluorescent quenching.The limits of detection of 1 and 2 for TNP were 0.107 and 0.327μmol·L^(-1),respectively.CCDC:2475515,1;2475516,2.
文摘The morphology of active layer plays a critical role in determining the photovoltaic performance of organic solar cells(OSCs).However,binary blends often suffer from suboptimal phase separation,which limits the efficiency of OSCs.Herein,two bridging polymer acceptors(PAs)—benzodithiophene-(2-ethylhexyl)oxy(BDT-C2C4)and benzodithiophene-octyloxy(BDT-C_(8))—are designed and synthesized by combining a benzodithiophene(BDT)unit as the donor moiety[poly({4,8-bis[5-(2-ethylhexyl)-4-fluorothiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}){5,8-bis[4-(2-butyloctyl)thiophen-2-yl]dithieno[3',2':3,4]},D18],and a 2,2′-((2Z,2′Z)-{[12,13-Bis(2-butyloctyl)-12,13-dihydro-3,9-dinonylthieno[2,3]thieno[3,2-b]pyrrolo[4,5-g]thieno[2,3-b]indole-2,10-diyl]bis(methanylylidene)}bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(Y6)derivative as the acceptor moiety.BDT-C2C4 and BDT-C_(8) are functionalized with(2-ethylhexyl)oxy and octyloxy side chains on the BDT unit,respectively.Both PAs show complementary absorption and cascaded energy levels with the donor D18 and the acceptor 2,2′-((2Z,2′Z)-{[12,13-bis(3-ethylheptyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3″∶4′,5′]thieno[2′,3′∶4,5]pyrrolo[3,2-g]thieno[2′,3′∶4,5]thieno[3,2-b]indole-2,10-diyl]bis(meth⁃aneylylidene)}bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(N3),but BDT-C_(8) exhibits better compatibility with D18 and N3 compared to BDT-C2C4.When incorporated as a third component into the D18∶N3 blend,both PAs improve the active layer morphology.In particular,the D18∶N3∶BDT-C_(8) blend shows significantly optimized morphology,featuring reduced phase separation and a fibrous network structure.As a result,the device based on D18∶N3∶BDT-C_(8) achieves a power conversion efficiency of 18.18%,significantly higher than that of the device based on D18∶N3(ca.17.37%).This work presents a compatibilizer strategy for optimizing blend morphology towards high-performance ternary OSCs.
基金financially supported by the National Natural Science Foundation of China(Nos.52533015,52495013,52403211,52573183,52273157,52073279 and 52025035)Jilin Province,China(Nos.20250601009RC and 20230508102RC)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022224)。
文摘Given that platinum-based drugs are widely used clinically as chemotherapeutic agents,their severe toxic side effects have attracted significant attention.Consequently,the development of novel nanoprodrugs based on low-toxicity tetravalent platinum(Pt(Ⅳ))com plexes holds substantial research value.Herein,we discovered that coumarin derivatives exhibit inherent antitumor efficacy and significantly enhance superoxide anion radicals(·O_(2)^(-))generation in aqueous solutions under ultrasound(US)irradiation.Given that·O_(2)^(-)is known to mediate the reduction of Pt(Ⅳ)to divalent platinum(Pt(Ⅱ)),we engineered an US-responsive dual-drug nanoprodrug(P-cisPt(Ⅳ)@5-MOP).This nanoprodrug was prepared by covalently conjugating Pt(Ⅳ)and methoxy polyethylene glycol hydroxyl(m PEG-OH)to a poly(_(L)-glutamic acid)(PLG)carrier,followed by encapsulating coumarin derivatives.Under low-intensity US irradiation(1.5 W/cm^(2),1 MHz,10 min),P-cisPt(Ⅳ)@5-MOP achieved a Pt(Ⅳ)reduction rate of 91.4%.Furthermore,upon US exposure,its half-maximal inhibitory concentration(IC_(50))against 4T1 breast cancer cells decreased dramatically from 25.7μmol/L to 0.1μmol/L.Remarkably,this system combined with US therapy yielded a tumor inhibition rate of 90.9%,with 40%of tumor-bea ring mice achieving com plete eradication of tumors,while exhibiting low systemic toxicity.Collectively,this work not only identifies a novel sonosensitizer capable of generating·O_(2)^(-)but also develops a new class of ultrasound-activatable Pt(Ⅳ)nanoprodrug.
文摘D-π hybridization is a key structural feature that may significantly affect the intrinsic electronic properties of metallopolymers.Herein,we present the electrosynthesis and memristive properties of metallopolymers using the distinct d-π hybridization monomers R_(1) and R_(2).R_(1)(Ru^(Ⅱ)-(tpz)Cl_(2))features tetradentate ligands(tpz,6,6'-di(1H-pyrazol-1-yl)-2,2'-bipyridine)enforcing quasi-octahedral geometry;R_(2)(Ru^(Ⅱ)-(bpp)_(2))incorporates tridentate ligands(bpp,2,6-di(1H-pyrazol-1-yl)pyridine)inducing pronounced geometric distortion.The planar ligand(tpz)in R_(1) facilitates ordered molecular assembly through high conformational rigidity and extensive π-π stacking,resulting in increased molecular densities and enhanced morphological uniformity compared to R_(2) metallopolymers.Due to pyrazole’s weaker π-acceptance and strongerσ-donation compared to pyridine,R_(1) exhibits a 119 nm red-shift in metal-to-ligand charge transfer(MLCT)band and a 30 mV anodic shift in Ru^(+2/+3)redox potential relative to R_(2).Coupled with a reduced HOMO-LUMO gap,the uniform and ordered structure leads to a lower conductance decay constant in R_(1).Additionally,R_(2) metallopolymers exhibit superior memristive performance(characterized by lower switching voltage and higher switching ratio)via redox-induced aromatic transitions in axial ligands enhancing electronic delocalization.This work compares two metallopolymers with different ligand geometries,revealing how this difference leads to distinct charge transport and memristive behaviors.
基金financial support from the National Natural Science Foundation of China(Nos.22401274,U23B6011)the Jilin Provincial Science and Technology Department Program(No.20250102070JC)。
文摘Catalysts are key for olefin polymerization reactions and are also ubiquitous in catalysis science.Multinuclear metal catalysts have witnessed enhanced performances in catalytic reactions relative to mononuclear catalysts,but which substantially involve multi-step,tedious,and difficult synthesis.Herein,this study reports an intriguing approach to construct multi-nuclear catalysts for the milestoneα-diimine nickel catalysts using an oligomeric strategy.A polymerizable norbornene unit is incorporated into theα-diimine ligand backbone,leading to the formation of the monomeric nickel catalyst Ni_(1)and its corresponding oligomeric nickel catalysts(Ni_(3)and Ni_(5))with varying degrees of polymerization(DP=3 and 5).Notably,the oligomeric catalyst Ni_(5)was facilely scaled up(50 g-level),showed enhanced thermal stability,exhibited 4.6 times higher activity,and yielded polyethylene elastomer with a 379%increased molecular weight in ethylene polymerization,compared to the monomeric catalyst Ni_(1).Catalytic performance enhancements of oligomeric catalysts were found to be DP-dependent.The kilogram-scale polyethylene,produced using Ni_(5)in a 20 L reactor,presented a highly branched all-hydrocarbon structure,which demonstrated typical elastic properties(tensile strength:4 MPa,elastic recovery:SR=72%)along with great processability(MFI=3.0 g/10 min),insulating characteristics(volume resistivity=2×10^(16)Ω/m),and hydrophobicity(water vapor permeability:0.03 g/m^(2)/day),suggesting potentially practical applications.
基金supported by the National Natural Science Foundation of China(T2350008)the STI2030-Major Projects[2021ZD0203000(2021ZD0203003)]the Open Research Fund of the State Key Laboratory of Brain-Machine Intelligence,Zhejiang University(BMI2400014).
文摘Addiction,a complex and chronic neurobiological disorder,is characterized by compulsive substance use despite harmful consequences,leading to persistent alterations in brain function,particularly within the reward,motivation,and decision-making systems.Despite the availability of a range of treatment options,including pharmacotherapy and behavioral therapies,relapse remains a major challenge,with many individuals struggling to maintain long-term recovery.Current treatments often show limited efficacy,underscoring the need for novel therapeutic strategies that can address the underlying neurobiological disruptions in addiction.
基金supported by the National Natural Science Foundation of China(Nos.22275182,22075272,51973211,51833009,21674111 and 52261135541)the Ministry of Science and Technology of the People’s Republic of China(the National Key R&D Program of China,No.2022YFB4200400)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0520102)。
文摘Pure organic room-temperature phosphorescent(RTP)polymers possess good processability and flexibility over small molecular crystals.However,most of RTP polymers reported so far are based on non-conjugated polymers,and achieving efficient phosphorescent emission in RTP conjugated polymers(CPs)remains a significant challenge.Herein,we developed two RTP CPs(P(PSe ZPh-p-Ph)and P(PSe ZPh-m-Ph))by linking the phenoselenazine units with the para-and meta-phenylene units,respectively,to form the conjugated main chains.The phenylene linker with different lingking mode manipulates the effictiveπ-conjugation of the polymer backbones.Comparing with the para-linked P(PSe ZPh-pPh),meta-linked P(PSe ZPh-m-Ph)exhibit the decreased effectiveπ-conjugation and the enhanced contribution of selenium atoms to the frontier orbitals,leading to the larger spin-orbit coupling(SOC)constants and the accelerated phosphorescence radiative decay process.The P(PSe ZPhm-Ph)achieves a phosphorescence quantum yield of 21.4%in doped polystyrene films,which is among the highest efficiencies reported to date for pure organic RTP CPs.These CPs are applied to construct phosphorescent film sensors for oxygen detection with the high quenching constants(K_(sv))up to 14.80 kPa^(-1)and low detection of limit of 0.84 ppm,demostrating the potential for application in oxygen film sensors.
基金financially supported by the National Natural Science Foundation of China(Nos.22473105 and 22341302).
文摘This study uses all-atom molecular dynamics simulations to investigate the dislocation propagation, stress transmission, and mechanical properties in poly(p-phenylene terephthalamide) fibers under uniaxial tension. The results indicate that the dislocation propagates and the stress transfers not only along the fiber axis but also between adjacent molecular chains through hydrogen bonds, demonstrating their influence on the yield behavior. As the degree of polymerization increases, breakage of covalent bonds and interchain slippage contribute to the yield of fibers together. This work provides theoretical guidance for the design and manufacturing of high-performance fibers.
基金financial support from Natural Science Foundation of China (No.22161005)Guangxi Natural Science Foundation (Nos.2021GXNSFDA075005,2024GXNSFFA010001)。
文摘Albeit notable endeavors in the construction of organophosphorodithioates,the direct catalytic enantioselective synthesis of organophosphorodithioates still stands for a long-lasting challenge.Herein,an efficient organocatalytic enantioselective nucleophilic addition of vinylidene ortho-quinone methide with phosphinothioic thioanhydride as nucleophilic reagent has been achieved by the dual catalysis of cinchona alkaloid-derived squaramide and 4-dimethylaminopyridine.This protocol provides a straightforward approach for accessing a variety of axially chiral phosphorodithiolated styrenes in good yields(up to 98 %yield) with high stereoselectivities(up to 97 % ee and >99:1 E/Z).
基金supported by the National Natural Science Foundation of China(82071981)the Program of Youth Science and Technology Innovation and Entrepreneurship Outstanding Talents(Team)of Jilin Province,China(20230508063RC)+3 种基金the Excellent Youth Training Foundation of Jilin University,China(419080520665)the Innovation and Entrepreneurship Talent Funding Program of Jilin Province,Chinathe Health Special Project of the Finance Department of Jilin Province,Chinathe Graduate Innovation Fund of Jilin University,China(2025CX297)。
文摘The heterogeneity and invasiveness of cancer cells pose serious challenges in cancer diagnosis and treatment.Advancements and innovations in metal-based nanomedicines provide novel avenues for addressing these challenges.Metal-based nanomedicines possess unique physicochemical properties that enable their interaction with living organisms,thereby inducing complex biological responses.These nanomaterials have been extensively used to enhance the contrast and sensitivity of cancer imaging and to amplify the distinction between cancerous and healthy tissues.Moreover,these nanomaterials can effectively combat a wide spectrum of cancers through various methods,including drug delivery,radiotherapy,photothermal therapy(PTT),photodynamic therapy(PDT),sonodynamic therapy(SDT),biocatalytic therapy,ion interference therapy(IIT),and immunotherapy.Currently,there is still a need for a comprehensive summary on the metal-based nanomaterials for cancer diagnosis and treatment.Herein,we present a systematic and complete overview of action mechanisms and the applications of metal-based nanomaterials in cancer theranostics.A summary of common strategies for synthesizing and modifying metal-based nanomedicines is presented,and their biosafety is analyzed.Then,the latest developments in their applications for cancer imaging and anticancer treatment are provided.Finally,the key technical challenges and reasonable perspectives of metal-based nanomedicines for cancer theranostics in clinical applications are discussed.
基金supported by the Science and Technology Development Plan of Jilin Province(No.YDZJ202403009CGZH)Engineering Research Center of Coalbased Ecological Carbon Sequestration Technology of the Ministry of Education(No.MJST2025-1)+2 种基金Chinese Academy of Sciences(Changchun Branch)(No.2024SYHZ0038)Development and Reform Commission of Jilin Province of China(No.2024C019-5)Science and Technology Bureau of Changchun City of China(No.23SH08)。
文摘A polylactide(PLA)blend with simultaneous enhancement of strength,toughness,and heat resistance was successfully achieved by adding biodegradable poly(propylene carbonate)(PPC)and uniaxial pre-stretching.The effects of the PPC content(0 wt%-50 wt%)on the phase morphology and performance of the blends before and after pre-stretching were systematically investigated.Blending PPC initially reduced the strength,modulus,and heat resistance,but pre-stretching significantly enhanced these properties.In blends containing≤30 wt%PPC,where PPC formed a well-dispersed island-like phase within the PLA matrix,pre-stretching simultaneously enhanced strength,toughness,and heat resistance.The optimized pre-stretched 70/30 PLA/PPC(ps-70/30)blend achieved exceptional performance:tensile strength increased from 66.9MPa to 84.5 MPa,elongation at break dramatically improved from 6.8%to 115.1%,impact strength reached 55.1 k J/m^(2)(far exceeding neat PLA's 3.5 k J/m^(2)),and Vicat softening temperature(VST)increased by 60.6%to 101.8℃.Notably,the ps-70/30 blend retained excellent mechanical properties even after six months of aging.These improvements were attributed to the synergistic effects of the PPC incorporation and prestretching.PPC not only promoted the high orientation of the PLA molecular chains but also facilitated the formation of a stable crystalline phase during pre-stretching,thereby enhancing both the mechanical properties and heat resistance.However,when the PPC content exceeded 30wt%,phase inversion occurred,resulting in a continuous amorphous PPC phase that degraded the overall performance.This study demonstrated that a combination of controlled PPC incorporation and pre-stretching can effectively overcome PLA's brittleness of PLA while improving its heat resistance,offering a promising strategy for developing high-performance,fully biodegradable PLA materials suitable for industrial applications.
基金financially supported by the National Natural Science Foundation of China(Nos.22341304,22303100 and 12205270)the National Key R&D Program of China(Nos.2023YFA1008800 and 2020YFA0713601)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC0180303)。
文摘The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.
基金supported by the National Natural Science Foundation of China(Nos.52273017 and 52273016)Strategic Priority Program of the Chinese Academy of Sciences(No.ZDRW-CN-2023-1)Natural Science Foundation of Jilin Province(No.SKL202302033).
文摘Cyclic olefin copolymers(COCs)are highly valuable optical resins,but their productions on industry are fully limited by the monomer norbornene.Although ethylene/dicyclopentadiene(E/DCPD)copolymers provide a cost-effective alternative to commercially available COCs because of using low-cost DCPD as cyclic olefin monomer,these inherent unsaturated double bonds on E/DCPD copolymers cause low heat resistance,oxidation,and crosslinking during processing and storage.And E/DCPD copolymers usually showed lower glass-transition temperature(T_(g))compared with commercially available COCs.In this study,we studied the E-DCPD copolymerization catalyzed by a scandium complex and the sequential hydrogenation catalyzed by a nickel compound to prepare saturated copolymers H-(E/DCPD).The polymerization activities are high up to 5.86×10^(6)g/(molSc·h),and the resultant H-(E/DCPD)copolymers showed narrow polymer dispersity index(PDI=1.5–2.0).By changing the polymerization conditions,a series of H-(E/DCPD)copolymers with tunable DCPD incorporation(28.4 mol%–44.9 mol%)and a wide range of T_(g)(123–171°C)were obtained.H-(E/DCPD)copolymers exhibited excellent optical properties(transparency>90%,refractive index of 1.543),similar to those of commercial COCs,making them an alternative for high-performance optical applications.This method solves the problems of traditional E/DCPD copolymers and provides a practical way to produce stable and low-cost COCs,and is comparable with commercially available COC resins.
基金the China Scholarship Council(CSC)for a doctoral scholarship(Grant Nos.202006310030,202108530138 and 202108530139)。
文摘The performance of polymer electrolytes in lithium metal batteries(LMBs)is often hindered by strong Li^(+)-ligand coordination,which leads to tightly bound solvation shells and restricts ion transport by coupling it to polymer segmental motion.In this study,a low-content ionic plasticizer additive1-butyl-3-dimethylimidazolium bromide(BMImBr)was introduced into the PVDF-HFP/LiTFSI/DMF matrix to modulate the Li^(+)solvation environment.Unlike conventional dual-salt systems,the introduced Br-anions dynamically compete for Li^(+)coordination,disrupting the rigid Li^(+)-TFSI^(-)/DMF solvation shell and constructing a"statistically labile and diffuse ionic cloud"characterized by reduced coordination numbers,weakened binding energies,and a more diffuse electrostatic potential landscape.This restructured solvation environment facilitates partially decoupled Li^(+)transport,as evidenced by dielectric spectroscopy and molecular dynamics simulations.Furthermore,the in situ formation of a LiBr-rich solid electrolyte interphase(SEI)effectively stabilizes the Li-metal interface and significantly reduces interfacial resistance.As a result,the optimized polymer electrolyte delivers outstanding electrochemical performance,achieving a high ionic conductivity of 0.8×10^(-4) S/cm,ultra-stable symmetric cell cycling over 500 h,and superior capacity retention exceeding 94%after 150 cycles at 0.5 C.This study elucidates a dynamic ion transport mechanism driven by competitive anion coordination and provides a viable strategy for simultaneously addressing the conductivity-stability trade-off in solid-state lithium metal batteries.
基金financial support from the National Natural Science Foundation of China(No.21676036)the Natural Science Foundation of Chongqing(No.CSTB2023NSCQMSX0580)the Large-scale Equipment Sharing Fund of Chongqing University(No.202403150240 and 202503150091)。
文摘Vanadium-based materials have emerged as promising cathode candidates for aqueous zinc-ion batteries(AZIBs)due to their multivalent redox characteristics and diverse crystal structures,which enable high energy storage capacity.Nevertheless,practical applications are hindered by several critical challenges,including vanadium species dissolution,side-product formation,sluggish Zn^(2+)diffusion kinetics,and low electrical conductivity.Organic functionalization,benefiting from its structural tunability and abundant functional groups,has been proven to be an effective strategy for enhancing the electrochemical performance of vanadium-based cathodes.This review systematically summarizes recent advances in organic-functionalized vanadium-based cathodes.First,the energy storage mechanism of vanadiumbased cathodes and the fundamental properties of organic compounds relevant to cathode optimization are outlined.Then,the functions of organic compounds are comprehensively analyzed from four key perspectives:capacity improvement,conductivity enhancement,Zn^(2+)diffusion kinetics optimization,and cycling stability promotion.Furthermore,the specific electrochemical performance modulation effects and practical application examples of this strategy are discussed in detail.Finally,current limitations and challenges in this field are highlighted,and corresponding solutions and future research directions are proposed,offering theoretical guidance and insights for the development of high-performance vanadium-based cathodes for AZIBs.
