It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K 2Cr 2O 7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃ . Orange Ⅳ exhib...It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K 2Cr 2O 7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃ . Orange Ⅳ exhibited a sensitive second order derivative polarographic wave at -0 50 V( vs . SCE). This provides the basis for a sensitive and selective catalytic kinetic method for oxalate determination with second order derivative oscillopolarography. The effects of sulphuric acid, K 2Cr 2O 7, and orange Ⅳ concentrations, reaction temperature and reaction time were investigated. A calibration curve of oxalate in the range of 0 1-2 0 μg/mL was obtained by the fixed time procedure. The detection limit was 0 03 μg/ mL. The possible interference from co existing substances or ions was examined. The new method has a high sensitivity and a good selectivity compared to other existing methods for oxalic acid determination. It has been applied to the determination of micro amounts of oxalate in real urine samples with satisfactory results.展开更多
In this paper, the extremum of second-order directional derivatives, i.e. the gradient of first-order derivatives is discussed. Given second-order directional derivatives in three nonparallel directions, or given seco...In this paper, the extremum of second-order directional derivatives, i.e. the gradient of first-order derivatives is discussed. Given second-order directional derivatives in three nonparallel directions, or given second-order directional derivatives and mixed directional derivatives in two nonparallel directions, the formulae for the extremum of second-order directional derivatives are derived, and the directions corresponding to maximum and minimum are perpendicular to each other.展开更多
The design and the synthesis of two conjugated donor acceptor imidazole derivatives(1, 2) were carried out for second order nonlinear optics. The thermal properties, the transparency and second order nonlinear opti...The design and the synthesis of two conjugated donor acceptor imidazole derivatives(1, 2) were carried out for second order nonlinear optics. The thermal properties, the transparency and second order nonlinear optical properties of the molecules were investigated. The experimental results indicate that a good nonlinearity transparency thermal stability trade off is achieved for them.展开更多
With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular mat...With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular materials for second-order nonlinear optics remain a great challenge because of the strict requirement of the materials to possess a noncentrosymmetric structure.In this work,two benzothiadiazole(BTD)derivatives referred to as BTD-H and BTD-F were synthesized,and their NLO properties in the crystalline states were studied.It was found that introducing fluorine into the BTD backbone effectively tuned the crystal packing styles of BTD derivatives to a noncentrosymmetric system for effective second-order NLO responses.Such a strategy to induce the noncentrosymmetric structure by introducing the fluorine atoms and halogen interactions may provide guidance for future engineering of organic NLO molecular materials.展开更多
The microscopic and macroscopic second-order optical susceptibilities of ten benzene derivative molecules and three crystals were calculated and discussed,basing on the nonlinear optical active group theory.
In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving...In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving numerical method is proposed. An e-uniform global error estimate for the numerical solution and also to the numerical derivative are established. Numerical results are presented, which are in agreement with the theoretical predictions.展开更多
Guided by molecular networking,nine novel curvularin derivatives(1-9)and 16 known analogs(10-25)were isolated from the hydrothermal vent sediment fungus Penicillium sp.HL-50.Notably,compounds 5-7 represented a hybrid ...Guided by molecular networking,nine novel curvularin derivatives(1-9)and 16 known analogs(10-25)were isolated from the hydrothermal vent sediment fungus Penicillium sp.HL-50.Notably,compounds 5-7 represented a hybrid of curvularin and purine.The structures and absolute configurations of compounds 1-9 were elucidated via nuclear magnetic resonance(NMR)spectroscopy,X-ray diffraction,electronic circular dichroism(ECD)calculations,^(13)C NMR calculation,modified Mosher's method,and chemical derivatization.Investigation of anti-inflammatory activities revealed that compounds 7-9,11,12,14,15,and 18 exhibited significant suppressive effects against lipopolysaccharide(LPS)-induced nitric oxide(NO)production in murine macrophage RAW264.7 cells,with IC_(50)values ranging from 0.44 to 4.40μmol·L^(-1).Furthermore,these bioactive compounds were found to suppress the expression of inflammation-related proteins,including inducible NO synthase(i NOS),cyclooxygenase-2(COX-2),NLR family pyrin domain-containing protein 3(NLRP3),and nuclear factor kappa-B(NF-κB).Additional studies demonstrated that the novel compound 7 possessed potent antiinflammatory activity by inhibiting the transcription of inflammation-related genes,downregulating the expression of inflammation-related proteins,and inhibiting the release of inflammatory cytokines,indicating its potential application in the treatment of inflammatory diseases.展开更多
The poor reversibility and stability of Zn anodes greatly restrict the practical application of aqueous Zn-ion batteries(AZIBs),resulting from the uncontrollable dendrite growth and H_(2)O-induced side reactions durin...The poor reversibility and stability of Zn anodes greatly restrict the practical application of aqueous Zn-ion batteries(AZIBs),resulting from the uncontrollable dendrite growth and H_(2)O-induced side reactions during cycling.Electrolyte additive modification is considered one of the most effective and simplest methods for solving the aforementioned problems.Herein,the pyridine derivatives(PD)including 2,4-dihydroxypyridine(2,4-DHP),2,3-dihydroxypyridine(2,3-DHP),and 2-hydroxypyrdine(2-DHP),were em-ployed as novel electrolyte additives in ZnSO_(4)electrolyte.Both density functional theory calculation and experimental findings demonstrated that the incorporation of PD additives into the electrolyte effectively modulates the solvation structure of hydrated Zn ions,thereby suppressing side reactions in AZIBs.Ad-ditionally,the adsorption of PD molecules on the zinc anode surface contributed to uniform Zn deposi-tion and dendrite growth inhibition.Consequently,a 2,4-DHP-modified Zn/Zn symmetrical cell achieved an extremely long cyclic stability up to 5650 h at 1 mA cm^(-2).Furthermore,the Zn/NH_(4)V_(4)O_(10)full cell with 2,4-DHP-containing electrolyte exhibited an outstanding initial capacity of 204 mAh g^(-1),with a no-table capacity retention of 79%after 1000 cycles at 5 A g^(-1).Hence,this study expands the selection of electrolyte additives for AZIBs,and the working mechanism of PD additives provides new insights for electrolyte modification enabling highly reversible zinc anode.展开更多
We report five coordination polymers(CPs)based on fluorescent ligands[1,6-di(1H-imidazol-1-yl)pyrene(dip),9,10-di(1H-imidazol-1-yl)anthracene(dia)]and anionic ligands[cyclohexane-1,4-dicarboxylic acid(H_(2)cda),campho...We report five coordination polymers(CPs)based on fluorescent ligands[1,6-di(1H-imidazol-1-yl)pyrene(dip),9,10-di(1H-imidazol-1-yl)anthracene(dia)]and anionic ligands[cyclohexane-1,4-dicarboxylic acid(H_(2)cda),camphoric acid(H_(2)cpa)].In[Cd(dip)(cda)]·4H_(2)O}_(n)(1),the Cd^(2+)ions,acting as tetrahedral nodes,are linked by dipand cda^(2-)ligands with four Cd^(2+)ions into five-fold interpenetrating network array of topology of dia.In{[Cd(dip)(cpa)]·4H_(2)O}_(n)(2),the Cd^(2+)ions,acting as a 4-connector,are linked by cpa^(2-)and dip ligands into a 3D framework ofcds topology.In{[Ni(dia)_(2)Cl_(2)]·DMF}_(n)(3),the Ni^(2+)ion is linked by four dia ligands into a layer structure,and 1Dchannels of a cross-section of 1.35 nm×0.96 nm are formed.In{[Cd(dia)_(2)(H_(2)O)_(2)](NO_(3))_(2)·2DMSO}n(4),the dia ligandsconnected Cd^(2+)ions into a 2D layer,and 1D channels are formed between adjacent layers with a cross-section of0.87 nm×0.43 nm.In[Zn(dip)Cl_(2)]_(n)(5),the Zn^(2+)ion is linked by dip ligands into an infinite 1D chain.The infrared,thermal gravimetric,and fluorescent emission data were collected and analyzed for these coordination polymers.CCDC:2356055,1;2440075,2;2356057,3;2356057,4;2356059,5.展开更多
This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high con...This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high concentrations of 16 EPA PAHs(∑Parent-PAHs)in smelting subarea of studied petroleum refinery facility,total derivatives of PAHs[named as XPAHs,including nitro PAHs(NPAHs),chlorinated PAHs(Cl-PAHs),and brominated PAHs(Br-PAHs)]in gas(mean=1.57×10^(4)ng/m^(3)),total suspended particulate(TSP)(mean=4.33×10^(3) ng/m^(3))and soil(mean=4.37×10^(3) ng/g)in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility,surrounding residential areas and reference areas,indicating that petroleum refining processes would lead apparent derivation of PAHs.Especially,compared with those in residential and reference areas,gas samples in the petrochemical areas had higher∑NPAH/∑PAHs(mean=2.18),but lower∑Cl-PAH/∑PAHs(mean=1.43×10^(-1))and∑Br-PAH/∑PAHs ratios(mean=7.49×10^(-2)),indicating the richer nitrification of PAHs than chlorination during petrochemical process.The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure,and the ILCR(1.04×10^(-4))for petrochemical workers was considered to be potential high risk.Furthermore,one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area,and another 35 PAHs were found,including alkyl-PAHs,phenyl-PAHs and other species,indicat-ing that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.展开更多
An efficient strategy for construction of tricyclic thiazino[3,4-a]isoquinolines has been achieved via 4-dimethylamino-pyridine(DMAP)promoted[5+1]annulation of simple and readily available isoquinoline 1,4-zwitterion ...An efficient strategy for construction of tricyclic thiazino[3,4-a]isoquinolines has been achieved via 4-dimethylamino-pyridine(DMAP)promoted[5+1]annulation of simple and readily available isoquinoline 1,4-zwitterion withα-bromoketone.This protocol showed good substrate compatibility as an array of structurally and electronically diverse thiazino[3,4-a]isoquinolines prepared efficiently in moderate to good yields.It is particularly emphasized that although this reaction exhibits moderate stereoselectivity,the two diastereomers can be separated by column chromatography,providing an important molecular diversity foundation for the screening and structural optimization of subsequent drug lead compounds,as well as a simple and efficient method for constructing complex nitrogen-containing and sulfur-containing heterocyclic compounds.It has potential application value in the fields of medicinal chemistry and organic synthesis.展开更多
Chronic obstructive pulmonary disease(COPD)has garnered increased attention as a result of its persistent symptoms,which undermine patientsʼquality of life.Fudosteine has substantial advantages in the treatment of COP...Chronic obstructive pulmonary disease(COPD)has garnered increased attention as a result of its persistent symptoms,which undermine patientsʼquality of life.Fudosteine has substantial advantages in the treatment of COPD due to its high efficacy and low adverse effects.In this study,Fudosteine sulfonamide derivatives Series I and amine derivatives Series II were designed and synthesized,and their biological activities were evaluated.The results showed that compound 6f had outstanding anti-inflammatory action with an IC_(50) of 1.08 mmol/L,and a higher antioxidant capacity than the lead molecule.At the same time,molecular docking investigations have revealed that compound 6f establishes hydrogen bonds and hydrophobic contacts with the MUC5AC protein.Furthermore,derivative 1f inhibited PDE4A1 enzyme activity five times more than Fudosteine.2,2-Diphenyl-1-picrylhydrazyl(DPPH)free radical scavenging tests demonstrated that all examined substances had higher antioxidant activity than Fudosteine.This study established a solid foundation for further research into COPD drug therapy.展开更多
Two tetrasubstituted carbazole derivatives TBICz and TOXDCz have been designed and synthesized,which possess the twist skeletons and exhibit excellent thermal and morphological stabilities.Utilizing these novel compou...Two tetrasubstituted carbazole derivatives TBICz and TOXDCz have been designed and synthesized,which possess the twist skeletons and exhibit excellent thermal and morphological stabilities.Utilizing these novel compounds as host material,high efficiency solution-processed green phosphorescent organic light-emitting diodes(PhOLEDs)have been achieved.The high triplet energies of TBICz and TOXDCz ensure efficient energy transfer from the host to the phosphor and triplet exciton confinement on the phosphor.Solution-processable green phospho⁃rescent devices employing Ir(ppy)3 as vip and the two tetrasubstituted carbazole derivatives as hosts exhibit high ef⁃ficiencies.The best EL performance is achieved for the TBICz-based device,with a maximum current efficiency of 27.3 cd/A,a maximum power efficiency of 15.9 lm/W,and a maximum external quantum efficiency of 7.8%,which provides more host material options for solution-processed OLEDs.展开更多
The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively red...The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively reduce C=C or C=O bonds while preserving other functional groups within the molecule.This approach serves as a critical strategy for the directional synthesis of high-value molecules.However,achieving such selectivity remains challenging due to the thermodynamic equilibrium and kinetic competition between C=O and C=C bonds inα,β-unsaturated systems.Consequently,constructing precisely targeted catalytic systems is essential to overcome these limitations,offering both fundamental scientific significance and industrial application potential.Metal-organic frameworks(MOFs)and their derivatives have emerged as innovative platforms for designing such systems,owing to their programmable topology,tunable pore microenvironments,spatially controllable active sites,and modifiable electronic structures.This review systematically summarizes the research progress of MOF-based catalysts for selec-tive hydrogenation ofα,β-unsaturated aldehydes/ketones in the last decade,with emphasis on the design strategy,conformational relationship,and catalytic mechanism,aiming to provide new ideas for the design of targeted catalyt-ic systems for the selective hydrogenation ofα,β-unsaturated aldehydes/ketones.展开更多
In recent years,the study of higher-order topological states and their material realizations has become a research frontier in topological condensed matter physics.We demonstrate that twisted bilayer graphene with sma...In recent years,the study of higher-order topological states and their material realizations has become a research frontier in topological condensed matter physics.We demonstrate that twisted bilayer graphene with small twist angles behaves as a second-order topological insulator possessing topological corner charges.Using a tight-binding model,we compute the topological band indices and corner states of finite-sized twisted bilayer graphene flakes.It is found that for any small twist angle,whether commensurate or incommensurate,the gaps both below and above the flat bands are associated with nontrivial topological indices.Our results not only extend the concept of second-order band topology to arbitrary small twist angles but also confirm the existence of corner states at acute-angle corners.展开更多
Continuous control protocols are extensively utilized in traditional MASs,in which information needs to be transmitted among agents consecutively,therefore resulting in excessive consumption of limited resources.To de...Continuous control protocols are extensively utilized in traditional MASs,in which information needs to be transmitted among agents consecutively,therefore resulting in excessive consumption of limited resources.To decrease the control cost,based on ISC,several LFC problems are investigated for second-order MASs without and with time delay,respectively.Firstly,an intermittent sampled controller is designed,and a sufficient and necessary condition is derived,under which state errors between the leader and all the followers approach zero asymptotically.Considering that time delay is inevitable,a new protocol is proposed to deal with the time-delay situation.The error system’s stability is analyzed using the Schur stability theorem,and sufficient and necessary conditions for LFC are obtained,which are closely associated with the coupling gain,the system parameters,and the network structure.Furthermore,for the case where the current position and velocity information are not available,a distributed protocol is designed that depends only on the sampled position information.The sufficient and necessary conditions for LFC are also given.The results show that second-order MASs can achieve the LFC if and only if the system parameters satisfy the inequalities proposed in the paper.Finally,the correctness of the obtained results is verified by numerical simulations.展开更多
Energy conversion and environmental pollution present significant challenges that necessitate the development of materials with optimal characteristics for effective applications in solar energy-driven photocatalysis....Energy conversion and environmental pollution present significant challenges that necessitate the development of materials with optimal characteristics for effective applications in solar energy-driven photocatalysis.Metal-organic frameworks(MOFs)serve as excellent platforms for the development of various MOF-derived materials,which have garnered extensive attention due to their unique structural features,high crystallinity,large surface areas,diverse morphologies,adjustable dimensions,tunable textural characteristics,and inherent catalytic activity.However,the sluggish charge kinetics and poor stability of MOFs and MOF-derived photocatalysts restrict their photocatalytic activity,thereby limiting their applications in the field of photocatalysis.Consequently,substantial research efforts have been directed toward maximizing the advantages of these intriguing materials while addressing their shortcomings.This review provides a comprehensive summary and analysis of various synthesis strategies of MOFs and their derivatives.Effective modification strategies to enhance the performance of these novel materials are also summarized.This review systematically explores the current advancements in the application of MOFs and their derivatives for photocatalytic water splitting,photocatalytic CO_(2)reduction,and environmental water pollution treatment.Finally,it discusses the challenges and future prospects of MOFs and MOF-derived materials in photocatalytic applications.Researchers should systematically optimize synthetic strategies and functionalize MOFs and their derivatives to enhance their application in energy conversion and environmental pollution control,thereby underscoring their extensive potential.Future research will increasingly concentrate on the intelligent design and functionalization of MOFs to attain superior catalytic performance and tackle the urgent energy and environmental challenges confronting the world.展开更多
The basidiomycetes Stereum hirsutum and Boreostereum vibrans are two fungi of the same genus.In this study,chemical investigation on the co-cultures of the two congeneric fungi led to the isolation of eleven new vibra...The basidiomycetes Stereum hirsutum and Boreostereum vibrans are two fungi of the same genus.In this study,chemical investigation on the co-cultures of the two congeneric fungi led to the isolation of eleven new vibralactone derivatives,hirsutavibrins A-K(1-11).The structures of 1-11 were elucidated by extensive NMR and HRESIMS spectroscopic analysis,and computational methods.Hirsutavibrins A(1)and B(2)showed weak cytotoxicity against the human lung cancer cell line A549.Hirsutavibrin D(4)showed moderate anti-nitric oxide activity in murine monocytic RAW 264.7 macrophages.This work not only expands the members of vibralactone derivatives with variable configurations but also opens a new avenue for fungal co-culturing study between congeneric fungi.展开更多
In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Usin...In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Using the perturbation method,we analyze the first-and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field.Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field.Comparing with traditional scheme for generating the second-order sideband,our spectral shape of the second-order sideband is amplified and becomes asymmetric,which has potential applications in precision measurement,high-sensitivity devices,and frequency conversion.展开更多
The stabilization problem of second-order bilinear systems with time delay is investigated.Feedback controls are chosen so that the strong and exponential stabilization of the system is ensured.The obtained results ar...The stabilization problem of second-order bilinear systems with time delay is investigated.Feedback controls are chosen so that the strong and exponential stabilization of the system is ensured.The obtained results are illustrated by wave and beam equations with simulation.展开更多
文摘It was found that micro amounts of oxalate showed a very strong catalytic effect on the slow reaction between K 2Cr 2O 7 and Orange Ⅳ in a diluted sulfuric acid medium in a water bath at 70 ℃ . Orange Ⅳ exhibited a sensitive second order derivative polarographic wave at -0 50 V( vs . SCE). This provides the basis for a sensitive and selective catalytic kinetic method for oxalate determination with second order derivative oscillopolarography. The effects of sulphuric acid, K 2Cr 2O 7, and orange Ⅳ concentrations, reaction temperature and reaction time were investigated. A calibration curve of oxalate in the range of 0 1-2 0 μg/mL was obtained by the fixed time procedure. The detection limit was 0 03 μg/ mL. The possible interference from co existing substances or ions was examined. The new method has a high sensitivity and a good selectivity compared to other existing methods for oxalic acid determination. It has been applied to the determination of micro amounts of oxalate in real urine samples with satisfactory results.
基金Supported by the National Natural Science Foundation of China (10871029,11071025)the Foundation of CAEP (2010A0202010)the Foundation of National Key Laboratory of Science and Technology on Computational Physics
文摘In this paper, the extremum of second-order directional derivatives, i.e. the gradient of first-order derivatives is discussed. Given second-order directional derivatives in three nonparallel directions, or given second-order directional derivatives and mixed directional derivatives in two nonparallel directions, the formulae for the extremum of second-order directional derivatives are derived, and the directions corresponding to maximum and minimum are perpendicular to each other.
基金Supported by the Natural Science Foundation of Hubei ProvinceChina(No.2 0 0 0 J15 6 )
文摘The design and the synthesis of two conjugated donor acceptor imidazole derivatives(1, 2) were carried out for second order nonlinear optics. The thermal properties, the transparency and second order nonlinear optical properties of the molecules were investigated. The experimental results indicate that a good nonlinearity transparency thermal stability trade off is achieved for them.
基金supported by China International Science and Technology Project (No. 2016YFE0114900)National Natural Science Foundation of China (No. 21761132007)
文摘With increasing research interests in the field of light-matter interactions,various methods have been developed for regulating nonlinear optical(NLO)materials.However,the design and synthesis of organic molecular materials for second-order nonlinear optics remain a great challenge because of the strict requirement of the materials to possess a noncentrosymmetric structure.In this work,two benzothiadiazole(BTD)derivatives referred to as BTD-H and BTD-F were synthesized,and their NLO properties in the crystalline states were studied.It was found that introducing fluorine into the BTD backbone effectively tuned the crystal packing styles of BTD derivatives to a noncentrosymmetric system for effective second-order NLO responses.Such a strategy to induce the noncentrosymmetric structure by introducing the fluorine atoms and halogen interactions may provide guidance for future engineering of organic NLO molecular materials.
文摘The microscopic and macroscopic second-order optical susceptibilities of ten benzene derivative molecules and three crystals were calculated and discussed,basing on the nonlinear optical active group theory.
基金the Council of Scientific and Industrial Research,New Delhi,India for its financial support.
文摘In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving numerical method is proposed. An e-uniform global error estimate for the numerical solution and also to the numerical derivative are established. Numerical results are presented, which are in agreement with the theoretical predictions.
基金funded by the National Key Research and Development Program of China(No.2022YFC2804101)the Guangdong Provincial Key R&D Program(No.2023B1111050011)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010432)the Guangzhou Basic and Applied Basic Research Foundation(No.202201010305)the High-Level Talents Special Program of Zhejiang(No.2022R52036)。
文摘Guided by molecular networking,nine novel curvularin derivatives(1-9)and 16 known analogs(10-25)were isolated from the hydrothermal vent sediment fungus Penicillium sp.HL-50.Notably,compounds 5-7 represented a hybrid of curvularin and purine.The structures and absolute configurations of compounds 1-9 were elucidated via nuclear magnetic resonance(NMR)spectroscopy,X-ray diffraction,electronic circular dichroism(ECD)calculations,^(13)C NMR calculation,modified Mosher's method,and chemical derivatization.Investigation of anti-inflammatory activities revealed that compounds 7-9,11,12,14,15,and 18 exhibited significant suppressive effects against lipopolysaccharide(LPS)-induced nitric oxide(NO)production in murine macrophage RAW264.7 cells,with IC_(50)values ranging from 0.44 to 4.40μmol·L^(-1).Furthermore,these bioactive compounds were found to suppress the expression of inflammation-related proteins,including inducible NO synthase(i NOS),cyclooxygenase-2(COX-2),NLR family pyrin domain-containing protein 3(NLRP3),and nuclear factor kappa-B(NF-κB).Additional studies demonstrated that the novel compound 7 possessed potent antiinflammatory activity by inhibiting the transcription of inflammation-related genes,downregulating the expression of inflammation-related proteins,and inhibiting the release of inflammatory cytokines,indicating its potential application in the treatment of inflammatory diseases.
基金supported by the Key Science and Technol-ogy Program of Henan Province(No.232102241020)the Ph.D.Research Startup Foundation of Henan University of Science and Technology(No.400613480015)+1 种基金the Postdoctoral Research Startup Foundation of Henan University of Science and Technology(No.400613554001)the Natural Science Foundation of Henan Province(242300420021).
文摘The poor reversibility and stability of Zn anodes greatly restrict the practical application of aqueous Zn-ion batteries(AZIBs),resulting from the uncontrollable dendrite growth and H_(2)O-induced side reactions during cycling.Electrolyte additive modification is considered one of the most effective and simplest methods for solving the aforementioned problems.Herein,the pyridine derivatives(PD)including 2,4-dihydroxypyridine(2,4-DHP),2,3-dihydroxypyridine(2,3-DHP),and 2-hydroxypyrdine(2-DHP),were em-ployed as novel electrolyte additives in ZnSO_(4)electrolyte.Both density functional theory calculation and experimental findings demonstrated that the incorporation of PD additives into the electrolyte effectively modulates the solvation structure of hydrated Zn ions,thereby suppressing side reactions in AZIBs.Ad-ditionally,the adsorption of PD molecules on the zinc anode surface contributed to uniform Zn deposi-tion and dendrite growth inhibition.Consequently,a 2,4-DHP-modified Zn/Zn symmetrical cell achieved an extremely long cyclic stability up to 5650 h at 1 mA cm^(-2).Furthermore,the Zn/NH_(4)V_(4)O_(10)full cell with 2,4-DHP-containing electrolyte exhibited an outstanding initial capacity of 204 mAh g^(-1),with a no-table capacity retention of 79%after 1000 cycles at 5 A g^(-1).Hence,this study expands the selection of electrolyte additives for AZIBs,and the working mechanism of PD additives provides new insights for electrolyte modification enabling highly reversible zinc anode.
文摘We report five coordination polymers(CPs)based on fluorescent ligands[1,6-di(1H-imidazol-1-yl)pyrene(dip),9,10-di(1H-imidazol-1-yl)anthracene(dia)]and anionic ligands[cyclohexane-1,4-dicarboxylic acid(H_(2)cda),camphoric acid(H_(2)cpa)].In[Cd(dip)(cda)]·4H_(2)O}_(n)(1),the Cd^(2+)ions,acting as tetrahedral nodes,are linked by dipand cda^(2-)ligands with four Cd^(2+)ions into five-fold interpenetrating network array of topology of dia.In{[Cd(dip)(cpa)]·4H_(2)O}_(n)(2),the Cd^(2+)ions,acting as a 4-connector,are linked by cpa^(2-)and dip ligands into a 3D framework ofcds topology.In{[Ni(dia)_(2)Cl_(2)]·DMF}_(n)(3),the Ni^(2+)ion is linked by four dia ligands into a layer structure,and 1Dchannels of a cross-section of 1.35 nm×0.96 nm are formed.In{[Cd(dia)_(2)(H_(2)O)_(2)](NO_(3))_(2)·2DMSO}n(4),the dia ligandsconnected Cd^(2+)ions into a 2D layer,and 1D channels are formed between adjacent layers with a cross-section of0.87 nm×0.43 nm.In[Zn(dip)Cl_(2)]_(n)(5),the Zn^(2+)ion is linked by dip ligands into an infinite 1D chain.The infrared,thermal gravimetric,and fluorescent emission data were collected and analyzed for these coordination polymers.CCDC:2356055,1;2440075,2;2356057,3;2356057,4;2356059,5.
基金supported by the National Key Research and Development Program of China(No.2019YFC1804501)the National Natural Science Foundation of China(Nos.22036007 and 22122611)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2020ME228)the Introduction and Cultivation Plan for Young Innovative Talents of Colleges and Universities.
文摘This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons(PAHs)and their derivatives in one Chinese petroleum refinery facility.It was found that,following with high concentrations of 16 EPA PAHs(∑Parent-PAHs)in smelting subarea of studied petroleum refinery facility,total derivatives of PAHs[named as XPAHs,including nitro PAHs(NPAHs),chlorinated PAHs(Cl-PAHs),and brominated PAHs(Br-PAHs)]in gas(mean=1.57×10^(4)ng/m^(3)),total suspended particulate(TSP)(mean=4.33×10^(3) ng/m^(3))and soil(mean=4.37×10^(3) ng/g)in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility,surrounding residential areas and reference areas,indicating that petroleum refining processes would lead apparent derivation of PAHs.Especially,compared with those in residential and reference areas,gas samples in the petrochemical areas had higher∑NPAH/∑PAHs(mean=2.18),but lower∑Cl-PAH/∑PAHs(mean=1.43×10^(-1))and∑Br-PAH/∑PAHs ratios(mean=7.49×10^(-2)),indicating the richer nitrification of PAHs than chlorination during petrochemical process.The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure,and the ILCR(1.04×10^(-4))for petrochemical workers was considered to be potential high risk.Furthermore,one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area,and another 35 PAHs were found,including alkyl-PAHs,phenyl-PAHs and other species,indicat-ing that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation.
文摘An efficient strategy for construction of tricyclic thiazino[3,4-a]isoquinolines has been achieved via 4-dimethylamino-pyridine(DMAP)promoted[5+1]annulation of simple and readily available isoquinoline 1,4-zwitterion withα-bromoketone.This protocol showed good substrate compatibility as an array of structurally and electronically diverse thiazino[3,4-a]isoquinolines prepared efficiently in moderate to good yields.It is particularly emphasized that although this reaction exhibits moderate stereoselectivity,the two diastereomers can be separated by column chromatography,providing an important molecular diversity foundation for the screening and structural optimization of subsequent drug lead compounds,as well as a simple and efficient method for constructing complex nitrogen-containing and sulfur-containing heterocyclic compounds.It has potential application value in the fields of medicinal chemistry and organic synthesis.
文摘Chronic obstructive pulmonary disease(COPD)has garnered increased attention as a result of its persistent symptoms,which undermine patientsʼquality of life.Fudosteine has substantial advantages in the treatment of COPD due to its high efficacy and low adverse effects.In this study,Fudosteine sulfonamide derivatives Series I and amine derivatives Series II were designed and synthesized,and their biological activities were evaluated.The results showed that compound 6f had outstanding anti-inflammatory action with an IC_(50) of 1.08 mmol/L,and a higher antioxidant capacity than the lead molecule.At the same time,molecular docking investigations have revealed that compound 6f establishes hydrogen bonds and hydrophobic contacts with the MUC5AC protein.Furthermore,derivative 1f inhibited PDE4A1 enzyme activity five times more than Fudosteine.2,2-Diphenyl-1-picrylhydrazyl(DPPH)free radical scavenging tests demonstrated that all examined substances had higher antioxidant activity than Fudosteine.This study established a solid foundation for further research into COPD drug therapy.
文摘Two tetrasubstituted carbazole derivatives TBICz and TOXDCz have been designed and synthesized,which possess the twist skeletons and exhibit excellent thermal and morphological stabilities.Utilizing these novel compounds as host material,high efficiency solution-processed green phosphorescent organic light-emitting diodes(PhOLEDs)have been achieved.The high triplet energies of TBICz and TOXDCz ensure efficient energy transfer from the host to the phosphor and triplet exciton confinement on the phosphor.Solution-processable green phospho⁃rescent devices employing Ir(ppy)3 as vip and the two tetrasubstituted carbazole derivatives as hosts exhibit high ef⁃ficiencies.The best EL performance is achieved for the TBICz-based device,with a maximum current efficiency of 27.3 cd/A,a maximum power efficiency of 15.9 lm/W,and a maximum external quantum efficiency of 7.8%,which provides more host material options for solution-processed OLEDs.
文摘The selective hydrogenation ofα,β-unsaturated aldehydes/ketones enables precise control over product structures and properties by regulating hydrogen transport pathways and bond cleavage sequences to selectively reduce C=C or C=O bonds while preserving other functional groups within the molecule.This approach serves as a critical strategy for the directional synthesis of high-value molecules.However,achieving such selectivity remains challenging due to the thermodynamic equilibrium and kinetic competition between C=O and C=C bonds inα,β-unsaturated systems.Consequently,constructing precisely targeted catalytic systems is essential to overcome these limitations,offering both fundamental scientific significance and industrial application potential.Metal-organic frameworks(MOFs)and their derivatives have emerged as innovative platforms for designing such systems,owing to their programmable topology,tunable pore microenvironments,spatially controllable active sites,and modifiable electronic structures.This review systematically summarizes the research progress of MOF-based catalysts for selec-tive hydrogenation ofα,β-unsaturated aldehydes/ketones in the last decade,with emphasis on the design strategy,conformational relationship,and catalytic mechanism,aiming to provide new ideas for the design of targeted catalyt-ic systems for the selective hydrogenation ofα,β-unsaturated aldehydes/ketones.
基金supported by the National Natural Science Foundation of China(Grant Nos.12104232 and 12074156).
文摘In recent years,the study of higher-order topological states and their material realizations has become a research frontier in topological condensed matter physics.We demonstrate that twisted bilayer graphene with small twist angles behaves as a second-order topological insulator possessing topological corner charges.Using a tight-binding model,we compute the topological band indices and corner states of finite-sized twisted bilayer graphene flakes.It is found that for any small twist angle,whether commensurate or incommensurate,the gaps both below and above the flat bands are associated with nontrivial topological indices.Our results not only extend the concept of second-order band topology to arbitrary small twist angles but also confirm the existence of corner states at acute-angle corners.
基金supported by the National Natural Science Foundation of China under Grants 62476138 and 42375016.
文摘Continuous control protocols are extensively utilized in traditional MASs,in which information needs to be transmitted among agents consecutively,therefore resulting in excessive consumption of limited resources.To decrease the control cost,based on ISC,several LFC problems are investigated for second-order MASs without and with time delay,respectively.Firstly,an intermittent sampled controller is designed,and a sufficient and necessary condition is derived,under which state errors between the leader and all the followers approach zero asymptotically.Considering that time delay is inevitable,a new protocol is proposed to deal with the time-delay situation.The error system’s stability is analyzed using the Schur stability theorem,and sufficient and necessary conditions for LFC are obtained,which are closely associated with the coupling gain,the system parameters,and the network structure.Furthermore,for the case where the current position and velocity information are not available,a distributed protocol is designed that depends only on the sampled position information.The sufficient and necessary conditions for LFC are also given.The results show that second-order MASs can achieve the LFC if and only if the system parameters satisfy the inequalities proposed in the paper.Finally,the correctness of the obtained results is verified by numerical simulations.
基金The financial support for this study by the Technology Project of Qingdao(22-3-7-cspz-9-nsh)the National Key Research and Development Program(2021YFB3500102)。
文摘Energy conversion and environmental pollution present significant challenges that necessitate the development of materials with optimal characteristics for effective applications in solar energy-driven photocatalysis.Metal-organic frameworks(MOFs)serve as excellent platforms for the development of various MOF-derived materials,which have garnered extensive attention due to their unique structural features,high crystallinity,large surface areas,diverse morphologies,adjustable dimensions,tunable textural characteristics,and inherent catalytic activity.However,the sluggish charge kinetics and poor stability of MOFs and MOF-derived photocatalysts restrict their photocatalytic activity,thereby limiting their applications in the field of photocatalysis.Consequently,substantial research efforts have been directed toward maximizing the advantages of these intriguing materials while addressing their shortcomings.This review provides a comprehensive summary and analysis of various synthesis strategies of MOFs and their derivatives.Effective modification strategies to enhance the performance of these novel materials are also summarized.This review systematically explores the current advancements in the application of MOFs and their derivatives for photocatalytic water splitting,photocatalytic CO_(2)reduction,and environmental water pollution treatment.Finally,it discusses the challenges and future prospects of MOFs and MOF-derived materials in photocatalytic applications.Researchers should systematically optimize synthetic strategies and functionalize MOFs and their derivatives to enhance their application in energy conversion and environmental pollution control,thereby underscoring their extensive potential.Future research will increasingly concentrate on the intelligent design and functionalization of MOFs to attain superior catalytic performance and tackle the urgent energy and environmental challenges confronting the world.
基金supported by the National Natural Science Foundation of China(Grant number 82473810)the Fundamental Research Funds for the Central Universities,South-Central Minzu University(Grant No.CPT22033).
文摘The basidiomycetes Stereum hirsutum and Boreostereum vibrans are two fungi of the same genus.In this study,chemical investigation on the co-cultures of the two congeneric fungi led to the isolation of eleven new vibralactone derivatives,hirsutavibrins A-K(1-11).The structures of 1-11 were elucidated by extensive NMR and HRESIMS spectroscopic analysis,and computational methods.Hirsutavibrins A(1)and B(2)showed weak cytotoxicity against the human lung cancer cell line A549.Hirsutavibrin D(4)showed moderate anti-nitric oxide activity in murine monocytic RAW 264.7 macrophages.This work not only expands the members of vibralactone derivatives with variable configurations but also opens a new avenue for fungal co-culturing study between congeneric fungi.
基金supported by the National Natural Science Foundation of China(Grant Nos.12174344 and 12175199)Foundation of Department of Science and Technology of Zhejiang Province(Grant No.2022R52047)。
文摘In this paper,we investigate the phenomena of electromagnetically induced transparency and the generation of second-order sideband in a Laguerre–Gaussian cavity optorotational system with a Kerr nonlinear medium.Using the perturbation method,we analyze the first-and second-order sideband generations in the output field from the system under the actions of a strong control field and a weak probe field.Numerical simulations show that the Kerr nonlinearity can lead to the occurrence of the asymmetric line shape in the transmission of the probe field.Comparing with traditional scheme for generating the second-order sideband,our spectral shape of the second-order sideband is amplified and becomes asymmetric,which has potential applications in precision measurement,high-sensitivity devices,and frequency conversion.
文摘The stabilization problem of second-order bilinear systems with time delay is investigated.Feedback controls are chosen so that the strong and exponential stabilization of the system is ensured.The obtained results are illustrated by wave and beam equations with simulation.
