Background:The study aimed to investigate the protective effect and mechanism of total flavonoids of Scutellaria baicalensis(TFSB)on acute myocardial ischemia(AMI)rats by using functional metabonomics.Methods:Rats wer...Background:The study aimed to investigate the protective effect and mechanism of total flavonoids of Scutellaria baicalensis(TFSB)on acute myocardial ischemia(AMI)rats by using functional metabonomics.Methods:Rats were divided into the Control,Model,AMI positive control(Propranolol hydrochloride,30 mg/kg),low dose TFSB(50 mg/kg),and high dose TFSB(100 mg/kg)groups.Rats received the corresponding treatment by intragastric administration once daily for 10 consecutive days.Electrocardiogram,myocardial enzyme,triphenyltetrazolium chloride staining,hematoxylin-eosin,and enzyme-linked immunosorbent assay were performed to evaluate the protective effect of TFSB on AMI rats.Then,the UHPLC-Q-Orbitrap MS method based on serum metabolomics was utilised to search for metabolic biomarkers and metabolic pathways.Subsequently,Western blot and RT-PCR techniques were employed to identify the respective genes and proteins.Results:Pharmacodynamics revealed that TFSB could ameliorate AMI in rats.The results of the metabolomics analysis indicated that the alterations in metabolic profile observed in rats with AMI were partially improved by treatment with TFSB.Moreover,the mRNA expression levels of 5-lipoxygenase(5-LOX)and 15-lipoxygenase(15-LOX)and the protein expression levels of 5-LOX,15-LOX,interleukin-1β(IL-1β),and NF-κB p65 were reduced following treatment with TFSB.Conclusion:The potential treatment of TFSB in AMI may be ascribed to its ability to regulate arachidonic acid metabolism.展开更多
Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperat...Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperatures and faces issues like low selectivity for liquid aromatics,separation difficulties,and rapid catalyst deactivation due to coking.To address this,a multifunctional Ni/HZSM-5 catalyst was developed to efficiently upgrade various polyolefins—including polyvinyl chloride—into gaseous alkanes(C_(1)–C_(5))and easily separable liquid aromatics(C_(6)–C_(12))at 400°C,without added solvents or hydrogen.Aromatic products make up 57.1 wt%of total output,with more than 97.8%selectivity for the liquid phase and a BTX(benzene,toluene,and xylene)selectivity of 76.1%.The high activity and selectivity for aromatics stem from synergistic interactions between Ni nanoparticles(NPs)and acid sites in the zeolite,which promote selective C–C bond breaking and control hydrogenolysis and aromatization pathways.This synergy allows precise control over the distribution of products by carbon number and favors the formation of separable aromatics.Notably,the catalyst also prevents coking by hydrogenolyzing and hydrogenating reactive intermediates before they form stable graphite-like deposits.Consequently,Ni/ZSM-5 catalyst demonstrates excellent stability,maintaining consistent aromatics yield over 13 consecutive cycles and processing over 30 times its weight in plastics without regeneration.After regeneration,the activity of the catalyst was fully restored,highlighting its potential for industrial use.This work offers valuable insights for designing durable,high-activity catalysts,providing a practical route to improve plastic recycling technologies.展开更多
Dear Editor,Lymphocyte activation gene 3(LAG3),the third established target for immune checkpoint blockade therapy,suppresses T cell function by binding to major histocompatibility complex classⅡ(MHCⅡ).Despite its s...Dear Editor,Lymphocyte activation gene 3(LAG3),the third established target for immune checkpoint blockade therapy,suppresses T cell function by binding to major histocompatibility complex classⅡ(MHCⅡ).Despite its significant therapeutic potential in cancer immunotherapy and the substantial attention it has received from academia and industry,the molecular mechanisms of LAG3-mediated immunosuppression remain poorly understood,primarily because of its unique ligand-binding characteristics and intracellular domains[1].展开更多
Both genders of the dioecious gymnosperm Ginkgo bilob a have distinct practical production and application uses,so quick,accurate identification of males and females is important for early seedling breeding.To develop...Both genders of the dioecious gymnosperm Ginkgo bilob a have distinct practical production and application uses,so quick,accurate identification of males and females is important for early seedling breeding.To develop a fast method to identify the sexes,we used the Easy DNA extraction(EZ-D)method to extract DNA from leaves within1 min for use with the recombinase polymerase amplification-lateral flow dipstick(RPA-LFD)system and identify the sex.A portable nucleic acid detection card kit(PNADCK)was used for on-site analysis.This method facilitates rapid extraction of nucleic acids from a single and can accurately detect 100 pg/μL of G.biloba female genomic DNA within20 min at 39°C.The EZ-DRPA-LFD-PNADCK system enables precise on-site determination of G.bilob a leaf sex and is rapid,efficient,sensitive,and convenient,greatly enhancing productivity for G.biloba because seedlings with specific sex characteristics can be selected at an earlier stage,planting strategies can be optimized,and production efficiency improved.展开更多
In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse...In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse relaxation time of the hydrogen nucleus was obtained by SIRT(Simultaneous Iterative Reconstruction Technique)inversion,and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed.The results showed that water existed in three main forms strongly bound water,weakly bound water and free water in camphor seeds.During the drying process,the peak position of strongly bound water remained unchanged,but the peak positions of weakly bound water and free water fluctuated.Drying rate increased with drying temperature increasing.In addition,there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis,and the correlation coefficient reached 0.984 4.展开更多
During aging at a temperature ranging from 650 -950 ℃,the ferric matrix in duplex stainless steels undergoes various decomposition processes which could form the precipitates of the Sigma （σ） and Chi （X） phases,...During aging at a temperature ranging from 650 -950 ℃,the ferric matrix in duplex stainless steels undergoes various decomposition processes which could form the precipitates of the Sigma （σ） and Chi （X） phases, as well as nitrides. It is well known that these precipitates lead to a reduction in creep ductility and adversely affect toughness and corrosion properties of steel. This experiment carded out qualitative and quantitative analyses of intermetallic phases and nitrides and established an analytical procedure, including specimen preparation, the choosing of the electrolyte and electrolytic systems,electrolytic isolation,wet chemical separation, and physical and chemical analysis, etc. The residues were collected by ultrasonic cleaning and filtration after galvanostatic electrolysis. Dynamic laser scattering sizer （DLS- sizer） ,scanning electron microscope （SEM） and transmission electron microscope （TEM） were used to examine their structure,modality and size. Qualitative and quantitative analyses were performed by using X-ray diffraction （XRD）, oxygen-nitrogen analyzer and wet chemical analysis. Furthermore, there is a discussion on the effect of isothermal treatment on precipitation that occurs at different temperatures for different periods of time.展开更多
Objective:To clone and express Rv3265c gene of Mycobacterium tuberculosis in Escherichia coli (E.coli) under optimistic conditions,obtain and identify protein expressed,analyze the structure and characteristics of the...Objective:To clone and express Rv3265c gene of Mycobacterium tuberculosis in Escherichia coli (E.coli) under optimistic conditions,obtain and identify protein expressed,analyze the structure and characteristics of the protein using bioinformatics methods for future applications.Methods: Rv3265c gene from Mycobacterium tuberculosis H37Rv was amplified by polymerase chain reaction,and was cloned into the pET-30a vector after purification and recovery.The recombinant plasmid was sequenced and expressed in E.coli BL21(DE3),and then purified and identified by western blotting.The essential physical-chemical properties of the protein were predicated by bioinformatics tools,including subcellular location,secondary structure,domains,antigenic epitopes,etc.Tertiary structure of the protein based on homology modeling was estabUshed,while multi-sequence homological alignment and phylogenetic analysis were preformed.Results:The recombinant protein was obtained in soluble fraction from expression system in E.coli B121(DE3) carrying pET30- Rv3265c plasmid,and Rv3265c gene was expressed correctly.Bioinformatics analysis showed the protein contained no signal peptide and transmembrane helices,located outside of membrane.Secondary structure analysis revealed it containedα-helix,extended strand and random coil,46.8%,14.6%,38.6%,respectively.Furthermore,it possessed six potential antigenic epitopes,one glycosyl transferase domain.A simple three-dimensional model of this protein was constructed by Swiss-model sever.Both sequences and structures were conservative and especial either in gene or in protein.Conclusions:Rv3265c gene might be a desirable molecular target for anti-tuberculosis drug and vaccine.The purified protein from expression will be utilized to study the kinetics of L-rhamnosyltransferase and to develope an enzyme assay for screening vaccine or drug.展开更多
Covalent organic nanospheres(CONs)were explored as a fiber coating for solid-phase microextraction of genotoxic impurities(GTIs)from active ingredients(AIs).CONs were synthesized by an easy solutionphase procedure at...Covalent organic nanospheres(CONs)were explored as a fiber coating for solid-phase microextraction of genotoxic impurities(GTIs)from active ingredients(AIs).CONs were synthesized by an easy solutionphase procedure at 25℃.The obtained nanospheres exhibited a high specific surface area,good thermostability,high acid and alkali resistance,and favorable crystallinity and porosity.Two types of GTIs,alkyl halides(1-iodooctane,1-chlorobenzene,1-bromododecane,1,2-dichlorobenzene,1-bromooctane,1-chlorohexane,and 1,8-dibromooctane)and sulfonate esters(methyl p-toluenesulfonate and ethyl ptoluenesulfonate),were chosen as target molecules for assessing the performance of the coating.The prepared coating achieved high enhancement factors(5097-9799)for the selected GTIs.The strong affinity between CONs and GTIs was tentatively attributed to π-π and hydrophobicity interactions,large surface area of the CONs,and size-matching of the materials.Combined with gas chromatography-mass spectrometry(GC-MS),the established analytical method detected the GTIs in capecitabine and imatinib mesylate samples over a wide linear range(0.2-200 ng/g)with a low detection limit(0.04-2.0 ng/g),satisfactory recovery(80.03%-109.5%),and high repeatability(6.20%-14.8%)and reproducibility(6.20%-14.1%).Therefore,the CON-coated fibers are promising alternatives for the sensitive detection of GTIs in AI samples.展开更多
The restriction of KB averaging method is discussed and asymptotic solution of the weakly nonlinear and forced oscillation u″+ω20u=εkcos ωt-εu3 is obtained by Struble technique. The conclusion about this oscillat...The restriction of KB averaging method is discussed and asymptotic solution of the weakly nonlinear and forced oscillation u″+ω20u=εkcos ωt-εu3 is obtained by Struble technique. The conclusion about this oscillation derived with other method is discussed. The results show that KB method will break down when a and θ in the zeroth solution of above eqation are not slowly varying functions of time t. The stationary solution of weakly nonlinear oscillation, u″+ω20u=εkcosω(ε)t-εu3 is also analysed.展开更多
Objective:To obtain fbpB-esxA fusing gene of Mycobacterium tuberculosis（MTU）,express the encoded fusing protein in Escherichia coli（E.coli）,identify protein acquired,and predict the structure and function of the p...Objective:To obtain fbpB-esxA fusing gene of Mycobacterium tuberculosis（MTU）,express the encoded fusing protein in Escherichia coli（E.coli）,identify protein acquired,and predict the structure and function of the protein utilizing methods of bioinformatics.Methods:fbpB and esxA gene were amplified from genome of MTB H37Rv by PCR.The fbpB-esxA fusing gene Iigated by（Gly<sub>4</sub>Ser）<sub>3</sub> linker was gained by means of Gene Splicing by Overlapping Extension PCU（SOEPCR）, and fusing gene was cloned into expression vector pET-30a.The recombinant plasmid was sequenced and expressed in E.coli BL21（DE3）.The protein was identified by Western blot using anti-HIS antibody.Secondary structure and antigenic epitopes of the protein were predicting using tools of bioinformatics.Results:The UNA sequences fbpB-esxA were identical with that published by GenBank.The Ag85B-ESAT-6 fusion protein about 50 kDa comprised 485 amino acids was efficiently produced from expression system in E.coli B1.21（DE3） under the induction of IPTG.Bioinformatics analysis showed the protein contained one transmembrane region and fourteen potential antigenic epitopes.Conclusions:The Ag85B-ESAT-6 fusion protein is successfully expressed with N-terminal HIS-tag.Gel filtration demonstrated that it exists as insoluble inclusion bodies mainly.The existence of linker doesn’t affect immunogenicity of Ag85B and ESAT-6.It will allow lor characterization in vitro and establish a foundation of further function research such as vaccine or diagnostic reagent.展开更多
In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface ...In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface were plotted to reveal the percentage contribution of various intermolecular contacts and location of the strongest hydrogen bond.Next,the solubility of malonamide in 12 solvents was determined by dynamic method at temperatures from 278.15 K to 318.15 K.Four thermodynamic models were applied to analyze solubility results.In addition,the thermodynamic properties were calculated to further analyze and discuss the dissolution behavior of malonamide.Moreover,the physicochemical properties of solvents were explored to express the solvent effects.The results illustrate“like dissolves like”,“mass transfer”and“solvent–solute interaction”rules play the synergistic effects on the dissolution process.The molecular dynamic simulation,including radial distribution function analysis and solvent free energy,was used to further explain the dissolution behavior.At last,the nucleation rate and effective interfacial energy in methanol solvent was measured and calculated to reveal the nucleation behaviour.展开更多
Segregation of solute atoms in the center of thick plates of the tempered steel can cause an inhomogeneous structural transformation and generate micron-sized inclusions,which leads to lamellar tearing of thick plate ...Segregation of solute atoms in the center of thick plates of the tempered steel can cause an inhomogeneous structural transformation and generate micron-sized inclusions,which leads to lamellar tearing of thick plate and decreases the plasticity and toughness.The formation and fragmentation mechanisms of micron-sized inclusions,like MnS and(Nb,Ti)C,in the center of thick plates were investigated by using thermodynamic calculations,finite element simulations,and electron backscatter diffraction characterization techniques.The results show that micron-sized inclusions nucleate and grow in the liquid phase,and under tensile loading,they exhibit three fragmentation mechanisms.The local stress during the fragmentation of inclusions is lower than the critical fracture stress of adjacent grains,and phase boundaries can effectively impede crack propagation into the matrix.The existence of a low proportion of high-angle grain boundaries(58.1%)and high Kernel average misorientation value(0.534°)in the segregation band promotes inclusions fragmentation and crack propagation.The difference in crack initiation and propagation direction caused by the morphology of inclusions and physical properties,as well as different matrix arrest abilities,is the main reasons for the diversity of inclusion fragmentation.展开更多
This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When expose...This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When exposed to nitrogen,the fracture mode of X42 pipeline steel undergoes ductile fracture,but in the presence of hydrogen,it shifts to brittle fracture.Moreover,an increase in hydrogen pressure or a decrease in punch velocity is found to enhance the hydrogen embrittlement susceptibility of X42 pipeline steel,as evidenced by the decrease of maximal load,displacement at failure onset and small punch energy.But the effect of pre-charge time on the hydrogen embrittlement susceptibility of X42 pipeline steel is not very obvious.Meanwhile,the presence of oxygen has been found to effectively inhibit hydrogen embrittlement.As the oxygen content in hydrogen increases,the hydrogen embrittlement susceptibility of X42 pipeline steel decreases.展开更多
We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmissio...We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmission electron microscopy is developed.Atomic behavior and lattice parameters of the nanobelt are studied using selected area electron diffraction.A statistical and least square methods are used for reducing the measurement errors of the lattice parameters.The results suggest that the trends of the lattice parameters during the tensile test are in agreement with the increasing tensile stress in the silicon nanobelt.Furthermore,the local strain calculated from lattice parameters and the average strain of the nanobelt are compared.展开更多
To study the volatile organic compounds(VOCs)emission characteristics of industrial enterprises in China,6 typical chemical industries in Yuncheng City were selected as research objects,including the modern coal chemi...To study the volatile organic compounds(VOCs)emission characteristics of industrial enterprises in China,6 typical chemical industries in Yuncheng City were selected as research objects,including the modern coal chemical industry(MCC),pharmaceutical industry(PM),pesticide industry(PE),coking industry(CO)and organic chemical industry(OC).The chemical composition of 91 VOCs was quantitatively analyzed.The results showed that the emission concentration of VOCs in the chemical industry ranged from 1.16 to 155.59 mg/m^(3).Alkanes were the main emission components of MCC(62.0%),PE(55.1%),and OC(58.5%).Alkenes(46.5%)were important components of PM,followed by alkanes(23.8%)and oxygenated volatile organic compounds(OVOCs)(21.2%).Halocarbons(8.6%-71.1%),OVOCs(9.7%-37.6%)and alkanes(11.2%-27.0%)were characteristic components of CO.The largest contributor to OFP was alkenes(0.6%-81.7%),followed by alkanes(9.3%-45.9%),and the lowest onewas alkyne(0%-0.5%).Aromatics(66.9%-85.4%)were the largest contributing components to SOA generation,followed by alkanes(2.6%-28.5%),and the lowest one was alkenes(0%-4.1%).Ethylene and BTEX were the key active species in various chemical industries.The human health risk assessment showed workers long-term exposed to the air in the chemical industrial zone had a high cancer and non-cancer risk during work,and BTEX and dichloromethane were the largest contributors.展开更多
Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental frien...Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.展开更多
Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In t...Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.展开更多
4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to b...4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to both human health and ecosystems.Herein,for the first time,we developed near-infrared(NIR)responsive upconversion luminescence nanosensor for NP detection.The Förster resonance energy transfer based upconversion nanoparticles(UCNPs)-graphene oxide sensor offers highly selective and sensitive detection of NP in linear ranges of 5−200 ng/mL and 200−1000 ng/mL under 980 nm and 808 nm excitation,respectively,with LOD at 4.2 ng/mL.The sensors were successfully tested for NP detection in real liquid milk samples with excellent recovery results.The rare-earth fluoride based upconversion luminescence nanosensor with NIR excitation wavelength,holds promise for sensing food,environmental,and biological samples due to their high sensitivity,specific recognition,low LOD,negligible autofluorescence,along with the deep penetration of NIR excitation sources.展开更多
In this work,the Si@reduced graphene oxide/ZrO_(2)(Si@rGO/ZrO_(2))with the shelled structures is prepared for the high-capacity and stable lithium-ion batteries.The shelled structure not only significantly improves th...In this work,the Si@reduced graphene oxide/ZrO_(2)(Si@rGO/ZrO_(2))with the shelled structures is prepared for the high-capacity and stable lithium-ion batteries.The shelled structure not only significantly improves the electrical conductivity of the whole electrode,but also protects the inner Si nanoparticles(Si NPs)from rupturing and being damaged by undesired side reactions with the electrolyte.As a result,the Si@rGO/ZrO_(2) anode delivers high initial discharge capacity of 3046 mAh·g^(−1) at 1.0 A·g^(−1).After 100 cycles,it can be maintained at 613 mAh·g^(−1),which is much higher than that of either the pure Si NPs(31 mAh·g^(−1))or the Si@rGO(261 mAh·g^(−1)).Even at 2 A·g^(−1),it still provides superior specific capacity of 834 mAh·g^(−1),while the pure Si anode merely possesses the capacity of 41 mAh·g^(−1).Moreover,the density functional theory calculations point out that ZrO_(2) layer can effectively enhance the adsorption energy of Li+and optimize the migration paths of Li+,ensuring the electrochemical performance of Si@rGO/ZrO_(2) composite anode.Furthermore,the Li+storage mechanism and low volume expansion of Si@rGO/ZrO_(2) anode is investigated by ex-situ X-ray photoelectron spectroscopy and morphological evolution upon cycling,respectively.展开更多
The complexity of living environment system demands higher requirements for the sensitivity and selectivity of the probe.Therefore,it is of great importance to develop a universal strategy for highperformance probe op...The complexity of living environment system demands higher requirements for the sensitivity and selectivity of the probe.Therefore,it is of great importance to develop a universal strategy for highperformance probe optimization.Herein,we propose a novel“Enrichment-enhanced Detection”strategy and use carbon dots-dopamine detection system as a representative model to evaluate its feasibility.The composite probe carbon dots (CDs)-encapsulated in glycol-chitosan (GC)(i.e.,CDs@GC) was obtained by simply mixing GC and CDs through noncovalent interactions,including electrostatic interactions and hydrogen bonding.Dopamine (DA) could be detected through internal filter effect (IFE)-induced quenching of CDs.In the case of CDs@GC,noncovalent interactions (electrostatic interactions) between GC and the formed quinone (oxide of DA) could selectively extract and enrich the local concentration of DA,thus effectively improving the sensitivity and selectivity of the sensing system.The nanosensor had a low detection limit of 3.7 nmol/L,which was a 12-fold sensitivity improvement compared to the bare CDs probes with similar fluorescent profiles,proving the feasibility of the“Enrichment-enhanced Detection”strategy.Further,to examine this theory in real case,we designed a highly portable sensing platform to realize visual determination of DA.Overall,our work introduces a new strategy for accurately detecting DA and provides valuable insights for the universal design and optimization of superior nanoprobes.展开更多
基金sponsored by Shandong Provincial Key Research and Development Program(Major Technological Innovation Project)([2021]CXGC010508)Guizhou Province Youth Science and Technology Talent Plan(YQK[2023]038)+1 种基金Science and Technology Department of Zunyi City of Guizhou province of China([2020]7)Key project at central government level:the ability establishment of sustainable use for valuable Chinese medicine resources(2060302).
文摘Background:The study aimed to investigate the protective effect and mechanism of total flavonoids of Scutellaria baicalensis(TFSB)on acute myocardial ischemia(AMI)rats by using functional metabonomics.Methods:Rats were divided into the Control,Model,AMI positive control(Propranolol hydrochloride,30 mg/kg),low dose TFSB(50 mg/kg),and high dose TFSB(100 mg/kg)groups.Rats received the corresponding treatment by intragastric administration once daily for 10 consecutive days.Electrocardiogram,myocardial enzyme,triphenyltetrazolium chloride staining,hematoxylin-eosin,and enzyme-linked immunosorbent assay were performed to evaluate the protective effect of TFSB on AMI rats.Then,the UHPLC-Q-Orbitrap MS method based on serum metabolomics was utilised to search for metabolic biomarkers and metabolic pathways.Subsequently,Western blot and RT-PCR techniques were employed to identify the respective genes and proteins.Results:Pharmacodynamics revealed that TFSB could ameliorate AMI in rats.The results of the metabolomics analysis indicated that the alterations in metabolic profile observed in rats with AMI were partially improved by treatment with TFSB.Moreover,the mRNA expression levels of 5-lipoxygenase(5-LOX)and 15-lipoxygenase(15-LOX)and the protein expression levels of 5-LOX,15-LOX,interleukin-1β(IL-1β),and NF-κB p65 were reduced following treatment with TFSB.Conclusion:The potential treatment of TFSB in AMI may be ascribed to its ability to regulate arachidonic acid metabolism.
基金supported by the National Key R&D Program of China(2021YFA1501700)the National Natural Science Foundation of China(22272114)+2 种基金the Funding for Hundred Talent Program(20822041E4079)the Fundamental Research Funds from Sichuan University(2022SCUNL103)This work has also been supported by SINOPEC Research Institute of Petroleum Processing Co.,Ltd.via collaborative project No.36800000-24-ZC0607-0175.
文摘Converting waste plastics directly into valuable aromatic chemicals is a promising,cost-effective recycling strategy.Traditional zeolite-catalyzed cracking of polyolefins to produce aromatics often needs high temperatures and faces issues like low selectivity for liquid aromatics,separation difficulties,and rapid catalyst deactivation due to coking.To address this,a multifunctional Ni/HZSM-5 catalyst was developed to efficiently upgrade various polyolefins—including polyvinyl chloride—into gaseous alkanes(C_(1)–C_(5))and easily separable liquid aromatics(C_(6)–C_(12))at 400°C,without added solvents or hydrogen.Aromatic products make up 57.1 wt%of total output,with more than 97.8%selectivity for the liquid phase and a BTX(benzene,toluene,and xylene)selectivity of 76.1%.The high activity and selectivity for aromatics stem from synergistic interactions between Ni nanoparticles(NPs)and acid sites in the zeolite,which promote selective C–C bond breaking and control hydrogenolysis and aromatization pathways.This synergy allows precise control over the distribution of products by carbon number and favors the formation of separable aromatics.Notably,the catalyst also prevents coking by hydrogenolyzing and hydrogenating reactive intermediates before they form stable graphite-like deposits.Consequently,Ni/ZSM-5 catalyst demonstrates excellent stability,maintaining consistent aromatics yield over 13 consecutive cycles and processing over 30 times its weight in plastics without regeneration.After regeneration,the activity of the catalyst was fully restored,highlighting its potential for industrial use.This work offers valuable insights for designing durable,high-activity catalysts,providing a practical route to improve plastic recycling technologies.
文摘Dear Editor,Lymphocyte activation gene 3(LAG3),the third established target for immune checkpoint blockade therapy,suppresses T cell function by binding to major histocompatibility complex classⅡ(MHCⅡ).Despite its significant therapeutic potential in cancer immunotherapy and the substantial attention it has received from academia and industry,the molecular mechanisms of LAG3-mediated immunosuppression remain poorly understood,primarily because of its unique ligand-binding characteristics and intracellular domains[1].
基金supported by the National Natural Science Foundation of China(Grant 32471873)the Major Projects in Agricultural Biological Breeding(Grant 2023ZD04056)+3 种基金the National Key R&D Program of China(Grant 2023YFD1401304)the Natural Science Foundation of Jiangsu Province,China(Grants BK20221426,BK20231291)the China Postdoctoral Science Foundation project(Grant 2024M751426)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant KYCX241264)。
文摘Both genders of the dioecious gymnosperm Ginkgo bilob a have distinct practical production and application uses,so quick,accurate identification of males and females is important for early seedling breeding.To develop a fast method to identify the sexes,we used the Easy DNA extraction(EZ-D)method to extract DNA from leaves within1 min for use with the recombinase polymerase amplification-lateral flow dipstick(RPA-LFD)system and identify the sex.A portable nucleic acid detection card kit(PNADCK)was used for on-site analysis.This method facilitates rapid extraction of nucleic acids from a single and can accurately detect 100 pg/μL of G.biloba female genomic DNA within20 min at 39°C.The EZ-DRPA-LFD-PNADCK system enables precise on-site determination of G.bilob a leaf sex and is rapid,efficient,sensitive,and convenient,greatly enhancing productivity for G.biloba because seedlings with specific sex characteristics can be selected at an earlier stage,planting strategies can be optimized,and production efficiency improved.
文摘In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse relaxation time of the hydrogen nucleus was obtained by SIRT(Simultaneous Iterative Reconstruction Technique)inversion,and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed.The results showed that water existed in three main forms strongly bound water,weakly bound water and free water in camphor seeds.During the drying process,the peak position of strongly bound water remained unchanged,but the peak positions of weakly bound water and free water fluctuated.Drying rate increased with drying temperature increasing.In addition,there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis,and the correlation coefficient reached 0.984 4.
文摘During aging at a temperature ranging from 650 -950 ℃,the ferric matrix in duplex stainless steels undergoes various decomposition processes which could form the precipitates of the Sigma （σ） and Chi （X） phases, as well as nitrides. It is well known that these precipitates lead to a reduction in creep ductility and adversely affect toughness and corrosion properties of steel. This experiment carded out qualitative and quantitative analyses of intermetallic phases and nitrides and established an analytical procedure, including specimen preparation, the choosing of the electrolyte and electrolytic systems,electrolytic isolation,wet chemical separation, and physical and chemical analysis, etc. The residues were collected by ultrasonic cleaning and filtration after galvanostatic electrolysis. Dynamic laser scattering sizer （DLS- sizer） ,scanning electron microscope （SEM） and transmission electron microscope （TEM） were used to examine their structure,modality and size. Qualitative and quantitative analyses were performed by using X-ray diffraction （XRD）, oxygen-nitrogen analyzer and wet chemical analysis. Furthermore, there is a discussion on the effect of isothermal treatment on precipitation that occurs at different temperatures for different periods of time.
基金Supported by Research Program in higher educational institutes of The Education Department of Hainan Province(No.Hj2010-21)Research Program of The Health Department of Hainan Province(No.2007-44)+1 种基金Natural Science Fund of Hainan Province(No.2008-30837)Cultivation Program of Hainan Medical University (HY2010-006)
文摘Objective:To clone and express Rv3265c gene of Mycobacterium tuberculosis in Escherichia coli (E.coli) under optimistic conditions,obtain and identify protein expressed,analyze the structure and characteristics of the protein using bioinformatics methods for future applications.Methods: Rv3265c gene from Mycobacterium tuberculosis H37Rv was amplified by polymerase chain reaction,and was cloned into the pET-30a vector after purification and recovery.The recombinant plasmid was sequenced and expressed in E.coli BL21(DE3),and then purified and identified by western blotting.The essential physical-chemical properties of the protein were predicated by bioinformatics tools,including subcellular location,secondary structure,domains,antigenic epitopes,etc.Tertiary structure of the protein based on homology modeling was estabUshed,while multi-sequence homological alignment and phylogenetic analysis were preformed.Results:The recombinant protein was obtained in soluble fraction from expression system in E.coli B121(DE3) carrying pET30- Rv3265c plasmid,and Rv3265c gene was expressed correctly.Bioinformatics analysis showed the protein contained no signal peptide and transmembrane helices,located outside of membrane.Secondary structure analysis revealed it containedα-helix,extended strand and random coil,46.8%,14.6%,38.6%,respectively.Furthermore,it possessed six potential antigenic epitopes,one glycosyl transferase domain.A simple three-dimensional model of this protein was constructed by Swiss-model sever.Both sequences and structures were conservative and especial either in gene or in protein.Conclusions:Rv3265c gene might be a desirable molecular target for anti-tuberculosis drug and vaccine.The purified protein from expression will be utilized to study the kinetics of L-rhamnosyltransferase and to develope an enzyme assay for screening vaccine or drug.
基金supported by the Key Research and Development Program of Shandong Province(Grant No.:2019GSF111001)the National Natural Science Foundation of China(Grant No.:21906096)+2 种基金the Youth Science Funds of the Shandong Academy of Sciences(Grant No.:2019QN009)the Youth Ph.D.Cooperation Funds of Qilu University of Technology(Shandong Academy of Sciences,Grant No.:2018BSHZ0029)the Program for Taishan Scholars of Shandong Province(Grant No.:tsqn202103099).
文摘Covalent organic nanospheres(CONs)were explored as a fiber coating for solid-phase microextraction of genotoxic impurities(GTIs)from active ingredients(AIs).CONs were synthesized by an easy solutionphase procedure at 25℃.The obtained nanospheres exhibited a high specific surface area,good thermostability,high acid and alkali resistance,and favorable crystallinity and porosity.Two types of GTIs,alkyl halides(1-iodooctane,1-chlorobenzene,1-bromododecane,1,2-dichlorobenzene,1-bromooctane,1-chlorohexane,and 1,8-dibromooctane)and sulfonate esters(methyl p-toluenesulfonate and ethyl ptoluenesulfonate),were chosen as target molecules for assessing the performance of the coating.The prepared coating achieved high enhancement factors(5097-9799)for the selected GTIs.The strong affinity between CONs and GTIs was tentatively attributed to π-π and hydrophobicity interactions,large surface area of the CONs,and size-matching of the materials.Combined with gas chromatography-mass spectrometry(GC-MS),the established analytical method detected the GTIs in capecitabine and imatinib mesylate samples over a wide linear range(0.2-200 ng/g)with a low detection limit(0.04-2.0 ng/g),satisfactory recovery(80.03%-109.5%),and high repeatability(6.20%-14.8%)and reproducibility(6.20%-14.1%).Therefore,the CON-coated fibers are promising alternatives for the sensitive detection of GTIs in AI samples.
文摘The restriction of KB averaging method is discussed and asymptotic solution of the weakly nonlinear and forced oscillation u″+ω20u=εkcos ωt-εu3 is obtained by Struble technique. The conclusion about this oscillation derived with other method is discussed. The results show that KB method will break down when a and θ in the zeroth solution of above eqation are not slowly varying functions of time t. The stationary solution of weakly nonlinear oscillation, u″+ω20u=εkcosω(ε)t-εu3 is also analysed.
基金Supported by Research Program of The Health Department of Hainan Province(No.2007-44)Research Cultivation Program of Hainan Medical University(HY2010-006)+1 种基金Research Program in higher educational institutes of The Education Department of Hainan Province(No.Hj2010-21)Natural Science Fund of Hainan Province(No.2008~30837)
文摘Objective:To obtain fbpB-esxA fusing gene of Mycobacterium tuberculosis（MTU）,express the encoded fusing protein in Escherichia coli（E.coli）,identify protein acquired,and predict the structure and function of the protein utilizing methods of bioinformatics.Methods:fbpB and esxA gene were amplified from genome of MTB H37Rv by PCR.The fbpB-esxA fusing gene Iigated by（Gly<sub>4</sub>Ser）<sub>3</sub> linker was gained by means of Gene Splicing by Overlapping Extension PCU（SOEPCR）, and fusing gene was cloned into expression vector pET-30a.The recombinant plasmid was sequenced and expressed in E.coli BL21（DE3）.The protein was identified by Western blot using anti-HIS antibody.Secondary structure and antigenic epitopes of the protein were predicting using tools of bioinformatics.Results:The UNA sequences fbpB-esxA were identical with that published by GenBank.The Ag85B-ESAT-6 fusion protein about 50 kDa comprised 485 amino acids was efficiently produced from expression system in E.coli B1.21（DE3） under the induction of IPTG.Bioinformatics analysis showed the protein contained one transmembrane region and fourteen potential antigenic epitopes.Conclusions:The Ag85B-ESAT-6 fusion protein is successfully expressed with N-terminal HIS-tag.Gel filtration demonstrated that it exists as insoluble inclusion bodies mainly.The existence of linker doesn’t affect immunogenicity of Ag85B and ESAT-6.It will allow lor characterization in vitro and establish a foundation of further function research such as vaccine or diagnostic reagent.
基金financially supported by the Innovative Group Project of China (21621004)Demonstration Project of Integration of Science, Education and Industry in Qilu University of Technology (2020KJC-ZD09)
文摘In this study,the solid structure,dissolution behavior,thermodynamic properties and nucleation kinetics of malonamide were explored.Firstly,the Hirshfeld surface analysis and molecular electrostatic potential surface were plotted to reveal the percentage contribution of various intermolecular contacts and location of the strongest hydrogen bond.Next,the solubility of malonamide in 12 solvents was determined by dynamic method at temperatures from 278.15 K to 318.15 K.Four thermodynamic models were applied to analyze solubility results.In addition,the thermodynamic properties were calculated to further analyze and discuss the dissolution behavior of malonamide.Moreover,the physicochemical properties of solvents were explored to express the solvent effects.The results illustrate“like dissolves like”,“mass transfer”and“solvent–solute interaction”rules play the synergistic effects on the dissolution process.The molecular dynamic simulation,including radial distribution function analysis and solvent free energy,was used to further explain the dissolution behavior.At last,the nucleation rate and effective interfacial energy in methanol solvent was measured and calculated to reveal the nucleation behaviour.
基金the financial support to the National Natural Science Foundation of China(U20A20279)the technical support provided by Analysis and Test Center of Wuhan University of Science and Technology,China.
文摘Segregation of solute atoms in the center of thick plates of the tempered steel can cause an inhomogeneous structural transformation and generate micron-sized inclusions,which leads to lamellar tearing of thick plate and decreases the plasticity and toughness.The formation and fragmentation mechanisms of micron-sized inclusions,like MnS and(Nb,Ti)C,in the center of thick plates were investigated by using thermodynamic calculations,finite element simulations,and electron backscatter diffraction characterization techniques.The results show that micron-sized inclusions nucleate and grow in the liquid phase,and under tensile loading,they exhibit three fragmentation mechanisms.The local stress during the fragmentation of inclusions is lower than the critical fracture stress of adjacent grains,and phase boundaries can effectively impede crack propagation into the matrix.The existence of a low proportion of high-angle grain boundaries(58.1%)and high Kernel average misorientation value(0.534°)in the segregation band promotes inclusions fragmentation and crack propagation.The difference in crack initiation and propagation direction caused by the morphology of inclusions and physical properties,as well as different matrix arrest abilities,is the main reasons for the diversity of inclusion fragmentation.
基金supported by the National Key R&D Program of China(2021YFB4001601)the Youth Innovation Promotion Association CAS(2022187).
文摘This study investigated the effect of pressure,pre-charge time,punch velocity and oxygen content on the mechanical properties of X42 pipeline steel in gaseous hydrogen environment by using small punch test.When exposed to nitrogen,the fracture mode of X42 pipeline steel undergoes ductile fracture,but in the presence of hydrogen,it shifts to brittle fracture.Moreover,an increase in hydrogen pressure or a decrease in punch velocity is found to enhance the hydrogen embrittlement susceptibility of X42 pipeline steel,as evidenced by the decrease of maximal load,displacement at failure onset and small punch energy.But the effect of pre-charge time on the hydrogen embrittlement susceptibility of X42 pipeline steel is not very obvious.Meanwhile,the presence of oxygen has been found to effectively inhibit hydrogen embrittlement.As the oxygen content in hydrogen increases,the hydrogen embrittlement susceptibility of X42 pipeline steel decreases.
基金Supported by the National Basic Research Program of China under Grant Nos 2011CB309501,2012CB933301the Key Project of National Natural Science Foundation of China(NSFC)under Grant Nos 60936001,91123037+1 种基金the Youth Project of National Natural Science Foundation of China(NSFC)under Grant No 81201358the Fund for Creative Research of NSFC under Grant No 61021064.
文摘We present an experimental method for in-situ observation of the lattice behavior of a single crystal silicon nanobelt during uniaxial tensile testing.An in-situ silicon nanobelt tensile testing device for transmission electron microscopy is developed.Atomic behavior and lattice parameters of the nanobelt are studied using selected area electron diffraction.A statistical and least square methods are used for reducing the measurement errors of the lattice parameters.The results suggest that the trends of the lattice parameters during the tensile test are in agreement with the increasing tensile stress in the silicon nanobelt.Furthermore,the local strain calculated from lattice parameters and the average strain of the nanobelt are compared.
基金supported by the National Natural Science Foundation of China(No.41905108)the National Research Program for Key Issues in Air Pollution Control(No.DQ GG0532).
文摘To study the volatile organic compounds(VOCs)emission characteristics of industrial enterprises in China,6 typical chemical industries in Yuncheng City were selected as research objects,including the modern coal chemical industry(MCC),pharmaceutical industry(PM),pesticide industry(PE),coking industry(CO)and organic chemical industry(OC).The chemical composition of 91 VOCs was quantitatively analyzed.The results showed that the emission concentration of VOCs in the chemical industry ranged from 1.16 to 155.59 mg/m^(3).Alkanes were the main emission components of MCC(62.0%),PE(55.1%),and OC(58.5%).Alkenes(46.5%)were important components of PM,followed by alkanes(23.8%)and oxygenated volatile organic compounds(OVOCs)(21.2%).Halocarbons(8.6%-71.1%),OVOCs(9.7%-37.6%)and alkanes(11.2%-27.0%)were characteristic components of CO.The largest contributor to OFP was alkenes(0.6%-81.7%),followed by alkanes(9.3%-45.9%),and the lowest onewas alkyne(0%-0.5%).Aromatics(66.9%-85.4%)were the largest contributing components to SOA generation,followed by alkanes(2.6%-28.5%),and the lowest one was alkenes(0%-4.1%).Ethylene and BTEX were the key active species in various chemical industries.The human health risk assessment showed workers long-term exposed to the air in the chemical industrial zone had a high cancer and non-cancer risk during work,and BTEX and dichloromethane were the largest contributors.
基金supported by the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Nos.U21A20332,51771076,U21A200970,52301266)the Science and Technology Planning Project of Guangzhou(No.2024A04J3332)。
文摘Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.
基金support of the Key Science Research Project in Colleges and Universities of Anhui Province,China(No.2022AH050813)the Medical Special Cultivation Project of Anhui University of Science and Technology,China(No.YZ2023H2A002).
文摘Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.
文摘4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to both human health and ecosystems.Herein,for the first time,we developed near-infrared(NIR)responsive upconversion luminescence nanosensor for NP detection.The Förster resonance energy transfer based upconversion nanoparticles(UCNPs)-graphene oxide sensor offers highly selective and sensitive detection of NP in linear ranges of 5−200 ng/mL and 200−1000 ng/mL under 980 nm and 808 nm excitation,respectively,with LOD at 4.2 ng/mL.The sensors were successfully tested for NP detection in real liquid milk samples with excellent recovery results.The rare-earth fluoride based upconversion luminescence nanosensor with NIR excitation wavelength,holds promise for sensing food,environmental,and biological samples due to their high sensitivity,specific recognition,low LOD,negligible autofluorescence,along with the deep penetration of NIR excitation sources.
基金supported by the Natural Science Foundation of Ningxia(No.2022AAC05014).
文摘In this work,the Si@reduced graphene oxide/ZrO_(2)(Si@rGO/ZrO_(2))with the shelled structures is prepared for the high-capacity and stable lithium-ion batteries.The shelled structure not only significantly improves the electrical conductivity of the whole electrode,but also protects the inner Si nanoparticles(Si NPs)from rupturing and being damaged by undesired side reactions with the electrolyte.As a result,the Si@rGO/ZrO_(2) anode delivers high initial discharge capacity of 3046 mAh·g^(−1) at 1.0 A·g^(−1).After 100 cycles,it can be maintained at 613 mAh·g^(−1),which is much higher than that of either the pure Si NPs(31 mAh·g^(−1))or the Si@rGO(261 mAh·g^(−1)).Even at 2 A·g^(−1),it still provides superior specific capacity of 834 mAh·g^(−1),while the pure Si anode merely possesses the capacity of 41 mAh·g^(−1).Moreover,the density functional theory calculations point out that ZrO_(2) layer can effectively enhance the adsorption energy of Li+and optimize the migration paths of Li+,ensuring the electrochemical performance of Si@rGO/ZrO_(2) composite anode.Furthermore,the Li+storage mechanism and low volume expansion of Si@rGO/ZrO_(2) anode is investigated by ex-situ X-ray photoelectron spectroscopy and morphological evolution upon cycling,respectively.
基金the financial support from the National Natural Science Foundation of China(No.21904007)the Fundamental Research Funds for the Central Universities(China,No.2412022QD008)+1 种基金the Jilin Provincial Department of Education(China),the Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province(China)the Analysis and Testing Center of Northeast Normal University(China)。
文摘The complexity of living environment system demands higher requirements for the sensitivity and selectivity of the probe.Therefore,it is of great importance to develop a universal strategy for highperformance probe optimization.Herein,we propose a novel“Enrichment-enhanced Detection”strategy and use carbon dots-dopamine detection system as a representative model to evaluate its feasibility.The composite probe carbon dots (CDs)-encapsulated in glycol-chitosan (GC)(i.e.,CDs@GC) was obtained by simply mixing GC and CDs through noncovalent interactions,including electrostatic interactions and hydrogen bonding.Dopamine (DA) could be detected through internal filter effect (IFE)-induced quenching of CDs.In the case of CDs@GC,noncovalent interactions (electrostatic interactions) between GC and the formed quinone (oxide of DA) could selectively extract and enrich the local concentration of DA,thus effectively improving the sensitivity and selectivity of the sensing system.The nanosensor had a low detection limit of 3.7 nmol/L,which was a 12-fold sensitivity improvement compared to the bare CDs probes with similar fluorescent profiles,proving the feasibility of the“Enrichment-enhanced Detection”strategy.Further,to examine this theory in real case,we designed a highly portable sensing platform to realize visual determination of DA.Overall,our work introduces a new strategy for accurately detecting DA and provides valuable insights for the universal design and optimization of superior nanoprobes.
