Two new Components, spiramine N (1) and spiraminol (2) were isolated from Spiraea japonica var. aecuminata Franch. Their structureswere elucidated bychemical and spectxal means.
Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, t...Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, terpenes, alkaloids, steroids, phenylpropanoids,glycosides and chromenes from natural herbs or traditional medicinal plants, and helps us analyze the structure-activity relationship(SAR) of natural products in healing of peptic ulcer for further drug development.展开更多
Viburnum dilatatum(jiami in Chinese),belonging to the Caprifollaceae family,is widely distributed in Japan and China.Phytochemical investigations of Viburnum dilatatum(V.dilatatum)have resulted in the isolation of tri...Viburnum dilatatum(jiami in Chinese),belonging to the Caprifollaceae family,is widely distributed in Japan and China.Phytochemical investigations of Viburnum dilatatum(V.dilatatum)have resulted in the isolation of triterpenoids,phenolic glycosides essential oil,norisoprenoids,etc.Research results have shown that the chemical constituents of V.dilatatum possess various pharmacological activities,including antihyperglycemic,antioxidant activity and antiulcer effects.This study reviewed the chemical constituents and pharmacological activities of V.dilatatum to provide practical and useful information for further research and development of this plant.展开更多
The chemical structures of bagasse EMAL （enzymatic hydrolysis/mild acidolysis lignin） were revealed quantitatively with ^31p-NMR, DFRC （derivatization followed by reductive cleavage）. The thermochemical characteri...The chemical structures of bagasse EMAL （enzymatic hydrolysis/mild acidolysis lignin） were revealed quantitatively with ^31p-NMR, DFRC （derivatization followed by reductive cleavage）. The thermochemical characteristics of bagasse and bagasse EMAL were evaluated with thermogravimetry. The results show that bagasse EMAL is mainly formed by the phenolic hydroxyl group of guaiacyl and syringyl units. The DBDO content in bagasse EMAL was found to be 0.180 mmol.g^-1. The decomposition characteristics of bagasse EMAL under elevated temperature were much different from that of bagasse.展开更多
Agrochemicals,especially plant growth regulators(PGRs),are extensively used to modulate endogenous phytohormone signals in small quantities,significantly infiuencing plant growth and development.Plant hormones typical...Agrochemicals,especially plant growth regulators(PGRs),are extensively used to modulate endogenous phytohormone signals in small quantities,significantly infiuencing plant growth and development.Plant hormones typically exhibit diverse chemical structures,with common examples including indole rings,terpenoid frameworks,adenine motifs,cyclic lactones,cyclopentanones,and steroidal compounds,which are extensively employed in pesticides.This article explores the interactions and biological activities of small molecules on proteins,enzymes,and other reactive sites involved in the biosynthesis,metabolism,transport,and signal transduction pathways of various plant hormones.Additionally,it analyzes the structure-activity relationships(SARs)of pesticides incorporating these structural motifs to elucidate the relationship between active fragments,pharmacophores,and targets,highlighting the characteristics of potent small molecules and their derivatives.This comprehensive review aims to provide novel perspectives for the development and design of pesticides,offering valuable insights for researchers in the field.展开更多
This study reports the response of helium(He)ion irradiation on binary-phase structured alloy V_(34)Ti_(25)Cr_(10)Ni_(30)Pd1.The alloy consists of a VCr matrix with nano-sized TiNi precipitates and a B2 TiNi matrix wi...This study reports the response of helium(He)ion irradiation on binary-phase structured alloy V_(34)Ti_(25)Cr_(10)Ni_(30)Pd1.The alloy consists of a VCr matrix with nano-sized TiNi precipitates and a B2 TiNi matrix with nano-sized VCr precipitates.VCr is chemical-disordered and TiNi has a B2-ordered structure.The alloy was subjected to 400 keV He ion irradiation with a fluence of 1×10^(17)ions cm^(−2)at 450℃.The results show He bubbles within the chemical-disordered VCr matrix exhibit a near-spherical shape with a smaller size and higher density compared to that in chemical-ordered TiNi phase with a larger size,lower density,and faceted shape.This indicates the chemical-disordered VCr phase effectively suppresses He accumulation compared to the B2-ordered TiNi phase,emphasizing the dominance of chemical struc-tures in He bubble formation.The calculation of density functional theory(DFT)shows that Ti and Ni have lower vacancy formation energy than that of V and Cr,respectively,which results in the increased vacancy production in TiNi.Consequently,He bubbles in TiNi have a larger bubble size consistent with experimental observations of radiation-induced Ni segregation.These findings elucidate the roles of or-dered and disordered chemical structures in He bubble evolution,offering insights for the development of gas ion irradiation-resistant materials.展开更多
Facial amphiphilicity is an extraordinary chemical structure feature of a variety of antimicrobial peptides and polymers.Vast efforts have been dedicated to small molecular,macromolecular and dendrimer-like systems to...Facial amphiphilicity is an extraordinary chemical structure feature of a variety of antimicrobial peptides and polymers.Vast efforts have been dedicated to small molecular,macromolecular and dendrimer-like systems to mimic this highly preferred structure or conformation,including local facial amphiphilicity and global amphiphilicity.This work conceptualizes Facial Amphiphilicity Index(FAI)as a numerical value to quantitatively characterize the measure of chemical compositions and structural features in dictating antimicrobial efficacy.FAI is a ratio of numbers of charges to rings,representing both compositions of hydrophilicity and hydrophobicity.Cationic derivatives of multicyclic compounds were evaluated as model systems for testing antimicrobial selectivity against Gram-negative and Gram-positive bacteria.Both monocyclic and bicyclic compounds are non-antimicrobial regardless of FAIs.Antimicrobial efficacy was observed with systems having larger cross-sectional areas including tricyclic abietic acid and tetracyclic bile acid.While low and high FAIs respectively lead to higher and lower antimicrobial efficacy,in consideration of cytotoxicity,the sweet spot is typically suited with intermediate FAIs for each specific system.This can be well explained by the synergistic hydrophobic-hydrophobic and electrostatic interactions with bacterial cell membranes and the difference between bacterial and mammalian cell membranes.The adoption of FAI would pave a new avenue toward the design of next-generation antimicrobial macromolecules and peptides.展开更多
The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)co...The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)coupled with energy-dispersive X-ray spectroscopy(EDS),offers valuable structural and chemical information for the analysis of fossils.However,its primary limitation is the restriction to two-dimensional surface data,which limits the exploration of fossils’3D complexities.Conversely,3D X-ray microscopy(3D-XRM),also known as a novel form of micro-computed tomography(micro-CT)facilitates the non-destructive 3D reconstruction of fossil specimens.Nevertheless,it lacks the capability to provide in-situ compositional data.Acknowledging the constraints inherent in these individual techniques,and in response to the evolving requirements of paleontological research,this study introduces an integrated approach that combines 3D-XRM with EDS-coupled focused ion beam scanning electron microscopy(FIB-SEM).This innovative strategy is designed to synergize the advantages of both techniques,thereby addressing challenges that conventional methods cannot.It enables the rapid identification of regions of interest(ROI)within fossil specimens at micrometer resolution.Subsequently,this method collects detailed data on both 3D structures and chemical compositions at the nanometer scale for the identified ROI.This integrated approach represents a significant advancement in paleontological and geological research methodologies,promising to meet the increasing demands of these fields.展开更多
MAX phase ceramics is a large family of nanolaminate carbides and nitrides,which integrates the advantages of both metals and ceramics,in general,the distinct chemical inertness of ceramics and excellent physical prop...MAX phase ceramics is a large family of nanolaminate carbides and nitrides,which integrates the advantages of both metals and ceramics,in general,the distinct chemical inertness of ceramics and excellent physical properties like metals.Meanwhile,the rich chemical and structural diversity of the MAXs endows them with broad space for property regulation.Especially,a much higher self-lubricity,as well as wear resistance,than that of traditional alloys and ceramics,has been observed in MAXs at elevated temperatures in recent decades,which manifests a great application potential and sparks tremendous research interest.Aiming at establishing a correlation among structure,chemical composition,working conditions,and the tribological behaviors of MAXs,this work overviews the recent progress in their high-temperature(HT)tribological properties,accompanied by advances in synthesis and structure analysis.HT tribological-specific behaviors,including the stress responses and damage mechanism,oxidation mechanism,and wear mechanism,are discussed.Whereafter,the tribological behaviors along with factors related to the tribological working conditions are discussed.Accordingly,outlooks of MAX phase ceramics for future HT solid lubricants are given based on the optimization of present mechanical properties and processing technologies.展开更多
With the increase of energy consumption,the shortage of fossil resource,and the aggravation of environmental pollution,the development of cost-effective and environmental friendly bio-based energy storage devices has ...With the increase of energy consumption,the shortage of fossil resource,and the aggravation of environmental pollution,the development of cost-effective and environmental friendly bio-based energy storage devices has become an urgent need.As the second most abundant natural polymer found in nature,lignin is mainly produced as the by-product of paper pulping and bio-refining industries.It possesses several inherent advantages,such as low-cost,high carbon content,abundant functional groups,and bio-renewable,making it an attractive candidate for the rechargeable battery material.Consequently,there has been a surge of research interest in utilizing lignin or lignin-based carbon materials as the components of lithium-ion(LIBs)or sodium-ion batteries(SIBs),including the electrode,binder,separator,and electrolyte.This review provides a comprehensive overview on the research progress of lignin-derived materials used in LIBs/SIBs,especially the application of lignin-based carbons as the anodes of LIBs/SIBs.The preparation methods and properties of lignin-derived materials with different dimensions are systemically discussed,which emphasizes on the relationship between the chemical/physical structures of lignin-derived materials and the performances of LIBs/SIBs.The current challenges and future prospects of lignin-derived materials in energy storage devices are also proposed.展开更多
Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and adv...Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and advanced applications.However,the commonly utilized precursors,such as polyacrylonitrile and pitch,exhibit a lack of environmental sustainability,and their costs are heavily reliant on fluctuating petroleum prices.To meet the substantial market demand for CFs,significant efforts have been made to develop cost-effective and sustainable CFs derived from biomass.Lignin,the most abundant polyphenolic compound in nature,is emerging as a promising precursor which is well-suited for the production of CFs due to its renewable nature,low cost,high carbon content,and aromatic structures.Nevertheless,the majority of lignin raw materials are currently derived from pulping and biorefining industrial by-products,which are diverse and heterogeneous in nature,restricting the industrialization of lignin-derived CFs.This review classifies fossil-derived and biomass-derived CFs,starting from the sources and chemical structures of raw lignin,and outlines the preparation methods linked to the performance of lignin-derived CFs.A comprehensive discussion is presented on the relationship between the structural characteristics of lignin,spinning preparation,and structure-morphology-property of ligninderived CFs.Additionally,the potential applications of these materials in various domains,including energy,catalysis,composites,and other advanced products,are also described with the objective of spotlighting the unique merits of lignin.Finally,the current challenges faced and future prospects for the advancement of lignin-derived CFs are proposed.展开更多
Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and r...Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and reducing CO_(2)emissions in ironmaking process.The BC with different ratios of FW were carbonized in a fixed bed reactor,and the physicochemical structure of the coke derived from FW/BC co-carbonization was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,solid-state^(13)C nuclear magnetic resonance,optical microscopy,and scanning electron microscopy.The results reveal that the suitable incorporation of FW in BC is 10 wt.%,and the index of coke quality exhibits a good correlation with the optical anisotropy index and the aromaticity of the as-obtained cokes.The partial substitution of BC with FW exhibits potential benefits for colloid formation,owing to the higher hydrogen in FW.However,as the substitution ratio of BC with FW increases,it inhibits coke agglomeration due to more tortuous stacked structures formation during volatile releasing process.Moreover,it was identified that the substitution of higher BC ratios with FW results in the partial replacement of aromatic carbons by oxygenlinked carbons and aliphatic carbons.This substitution leads to a reduction in the aromaticity of the as-obtained coke.展开更多
Green prevention and control management of soil-borne fungal diseases is a hot topic in agriculture,ecology,and the environment.It is an important way to effectively prevent and control soil-borne fungal diseases,solv...Green prevention and control management of soil-borne fungal diseases is a hot topic in agriculture,ecology,and the environment.It is an important way to effectively prevent and control soil-borne fungal diseases,solve soil degradation caused by continuous cropping obstacles,and fulfill the sustainable development of agriculture through revealing the mechanisms of functional substances to develop highly effective soil amendments.Humic acid shows an inhibitory effect on soil-borne pathogenic fungi,such as Fusarium oxysporum,Choanephora cucurbitarum,and Rhizoctonia solani,with the inhibition rate exceeding 80%.The molecular and elemental composition and contents of–COOH,phenolic C,methoxy group C,carboxyl C,aromatic C–O,anomeric C,and other functional groups of humic acid have been inferred to be responsible for its inhibitory effects on pathogenic fungi in previous research.The inhibitory mechanisms mainly include cell physiological morphology,biochemical process reactions,and molecular signal transduction.This review systematically summarizes the chemical structure,fungistatic effects,variable characteristics,and inhibitory mechanisms of humic acid,aiming to provide a theoretical basis for the development of green and efficient prevention and control technologies for soil-borne fungal diseases.展开更多
Polycyclic polyprenylated acylphloroglucinols(PPAPs)represent a distinct subclass of specialized metabolites predominantly found in the plant kingdom,particularly within the Guttiferae(Clusiaceae)family.These compound...Polycyclic polyprenylated acylphloroglucinols(PPAPs)represent a distinct subclass of specialized metabolites predominantly found in the plant kingdom,particularly within the Guttiferae(Clusiaceae)family.These compounds exhibit remarkable structural diversity and a wide range of biological activities.Seco-and nor-PPAPs,two unique variants of PPAPs with diverse skeletal structures,have been extensively investigated.As of June 2023,200 compounds have been isolated from four genera,with Hypericum being the primary source.Notably,115 of these compounds were identified in the past four years,indicating a significant increase in research activity.Seco-and nor-PPAPs can be categorized into six main subgroups based on the original PPAP scaffolds.Biological studies have revealed their potential in various therapeutic applications,including anti-cancer,anti-inflammatory,hepatoprotective,anti-Alzheimer’s disease(anti-AD),multidrug resistance(MDR)reversal,anti-depressant,neuroprotective,and immunosuppressive effects.This review provides a comprehensive overview of the occurrence,structures,and bioactivities of natural seco-and nor-PPAPs,offering valuable insights for the further development of PPAPs.展开更多
Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural unit...Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural units affect the efficiency of CO_(2)photoreduction.Results from both experiments and density-functional theory(DFT)calculations indicate the separation and transfer of the photoinduced charges is highly related to the triazine-N content and the conjugation degree in the skeletons of COFs.High-efficiency CO_(2)photoreduction can be achieved by rationally adjusting the number and position of both benzene and triazine rings in the COFs.Specifically,TTA-TTB,with orderly interlaced triazine-benzene heterojunctions,can suppress the recombination probability of electrons and holes,which effectively immobilizes the key species(COOH)and lowers the free energy change of the potential-determining step,and thus exhibits a superior visible-light-induced photocatalytic activity that yields 121.7 μmol HCOOH g^(-1)h^(-1).This research,therefore,helps to elucidate the effects of the different structural blocks in COFs on inherent heterogeneous photocatalysis for CO_(2)reduction at a molecular level.展开更多
Swimming crab(Portunus trituberculatus)eggs contain abundant phospholipids and polyunsaturated fatty acids with specific bioactivities.However,more studies on the functions of other nutrients are needed.Here,a novel s...Swimming crab(Portunus trituberculatus)eggs contain abundant phospholipids and polyunsaturated fatty acids with specific bioactivities.However,more studies on the functions of other nutrients are needed.Here,a novel sialoglycopeptide from P.trituberculatus eggs,which was termed as Pt-SGP,was isolated with enzymolysis.Pt-SGP was a 6480-Da pure sialoglycopeptide.O-glycan units existed between peptides and sugars.Pt-SGP was composed of 10.69%protein,71.43%hexose,and 11.27%Neu5Gc acid.Analyzed with HPLC,GC-MS,and NMR spectrometry,the carbohydrate chain of Pt-SGP was{(4GlcNAc1-2Man1-3)/(4GlcNAc1-2Man1-6)Man1-6}/{4Glc1-4}Glc1-4Glc1-3GlcNAc1.The MS spectrometry analysis result showed that the peptide chain was Val-Ala-Thr*-Val-Ser*-Leu-Pro-Arg.The results on mice showed Pt-SGP could reduce body weight gain by 18.13%,white adipose weight by 28.57%,serum TC by 22.32,serum TG by 9.46%,serum LDL-C by 27.69%,hepatic TC by 73.21%,and hepatic TG by 25.20%.Furthernore,it could increase serum HDL-C by 75.96%,mitigate adipocyte size and hepatic lipid accumulation in high fat diet-fed mice.Pt-SGP significantly down-regulated C/EBPαsignaling and up-regulated AMPKαsignaling in the epididymal fat tissues.The findings indicate that Pt-SGP exhibits notable anti-obesity properties,and can potentially become a promising dietary supplement for anti-obesity.展开更多
Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, d...Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, diverse photocatalysts, including ruthenium(II), iridium(Ⅲ), and organic dyes, have been most commonly applied.展开更多
The current paper reviews the content and variation of fiber fractions in feed ingredients commonly used in swine diets.Carbohydrates serve as the main source of energy in diets fed to pigs.Carbohydrates may be classi...The current paper reviews the content and variation of fiber fractions in feed ingredients commonly used in swine diets.Carbohydrates serve as the main source of energy in diets fed to pigs.Carbohydrates may be classified according to their degree of polymerization:monosaccharides,disaccharides,oligosaccharides,and polysaccharides.Digestible carbohydrates include sugars,digestible starch,and glycogen that may be digested by enzymes secreted in the gastrointestinal tract of the pig.Non-digestible carbohydrates,also known as fiber,may be fermented by microbial populations along the gastrointestinal tract to synthesize short-chain fatty acids that may be absorbed and metabolized by the pig.These non-digestible carbohydrates include two disaccharides,oligosaccharides,resistant starch,and non-starch polysaccharides.The concentration and structure of non-digestible carbohydrates in diets fed to pigs depend on the type of feed ingredients that are included in the mixed diet.Cellulose,arabinoxylans,and mixed linkedβ-(1,3)(1,4)-D-glucans are the main cell wall polysaccharides in cereal grains,but vary in proportion and structure depending on the grain and tissue within the grain.Cell walls of oilseeds,oilseed meals,and pulse crops contain cellulose,pectic polysaccharides,lignin,and xyloglucans.Pulse crops and legumes also contain significant quantities of galacto-oligosaccharides including raffinose,stachyose,and verbascose.Overall,understanding the structure,characteristics and measurable chemical properties of fiber in feed ingredients may result in more accurate diet formulations,resulting in an improvement in the utilization of energy from less expensive high-fiber ingredients and a reduction in reliance on energy from more costly cereal grains.展开更多
The effect of different kinds of comonomers with or without flexible chain on properties of copolyesters, such as transition temperature, crystallization velocity, crystallinity and size Of crystallites, is studied. T...The effect of different kinds of comonomers with or without flexible chain on properties of copolyesters, such as transition temperature, crystallization velocity, crystallinity and size Of crystallites, is studied. The experimental results indicate the obvious difference in properties between comonomers with iso-and ortho-structure of phenyl ring and comonomers with flexible chain. The influence of chemical structure of comonomers on properties of copolyesters is discussed.展开更多
The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupansh...The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupanshui raw coal(LPS-R)and Liupanshui demineralized coal(LPS-D)were analyzed by FTIR and solid-state 13C-NMR.The pyrolysis experiments were carried out by TG,and the pyrolysis kinetics was analyzed by three iso-conversional methods.FTIR and 13C-NMR results suggested that the carbon structure of LPS coal was not altered greatly,while demineralization promoted the maturity of coal and the condensation degree of the aromatic ring,making the chemical structure of coal more stable.The oxygen-containing functional groups with low bond energy were reduced,and the ratio of aromatic carbon with high bond energy was increased,decreasing the pyrolysis reactivity.DTG curve-fitting results revealed that the thermal weight loss of LPS coal mainly came from the cleavage of aliphatic covalent bonds.By pyrolysis kinetics analysis of LPS-R and LPS-D,the apparent activation energies were 76±4 to 463±5 kJ/mol and 84±2 to 758±12 kJ/mol,respectively,under different conversion rates.The reactivity of the demineralized coal was inhibited to some extent,as the apparent activation energy of pyrolysis for LPS-D increased by acid treatment.展开更多
文摘Two new Components, spiramine N (1) and spiraminol (2) were isolated from Spiraea japonica var. aecuminata Franch. Their structureswere elucidated bychemical and spectxal means.
基金supported by the National Natural Science Foundation of China(No.21272136)Youth Talent Development Foundation of China Three Gorges University
文摘Natural products provide an important original source of structural diversity for finding new compounds as anti-peptic ulcer drugs. The present review highlights some recent advances on gastro-protective flavonoids, terpenes, alkaloids, steroids, phenylpropanoids,glycosides and chromenes from natural herbs or traditional medicinal plants, and helps us analyze the structure-activity relationship(SAR) of natural products in healing of peptic ulcer for further drug development.
文摘Viburnum dilatatum(jiami in Chinese),belonging to the Caprifollaceae family,is widely distributed in Japan and China.Phytochemical investigations of Viburnum dilatatum(V.dilatatum)have resulted in the isolation of triterpenoids,phenolic glycosides essential oil,norisoprenoids,etc.Research results have shown that the chemical constituents of V.dilatatum possess various pharmacological activities,including antihyperglycemic,antioxidant activity and antiulcer effects.This study reviewed the chemical constituents and pharmacological activities of V.dilatatum to provide practical and useful information for further research and development of this plant.
基金The authors are grateful for the financial support of this research from the National Natural Science Foundation of China(No.30371138 and 20576043)the Visiting Scholarship Grant from the Key Laboratory of Lignocellulosics Chemistry,Chinese Academy of Sciences(No.109).
文摘The chemical structures of bagasse EMAL （enzymatic hydrolysis/mild acidolysis lignin） were revealed quantitatively with ^31p-NMR, DFRC （derivatization followed by reductive cleavage）. The thermochemical characteristics of bagasse and bagasse EMAL were evaluated with thermogravimetry. The results show that bagasse EMAL is mainly formed by the phenolic hydroxyl group of guaiacyl and syringyl units. The DBDO content in bagasse EMAL was found to be 0.180 mmol.g^-1. The decomposition characteristics of bagasse EMAL under elevated temperature were much different from that of bagasse.
基金The financial support from the National Key Research and Development Program of China(No.2023YFD1700600)。
文摘Agrochemicals,especially plant growth regulators(PGRs),are extensively used to modulate endogenous phytohormone signals in small quantities,significantly infiuencing plant growth and development.Plant hormones typically exhibit diverse chemical structures,with common examples including indole rings,terpenoid frameworks,adenine motifs,cyclic lactones,cyclopentanones,and steroidal compounds,which are extensively employed in pesticides.This article explores the interactions and biological activities of small molecules on proteins,enzymes,and other reactive sites involved in the biosynthesis,metabolism,transport,and signal transduction pathways of various plant hormones.Additionally,it analyzes the structure-activity relationships(SARs)of pesticides incorporating these structural motifs to elucidate the relationship between active fragments,pharmacophores,and targets,highlighting the characteristics of potent small molecules and their derivatives.This comprehensive review aims to provide novel perspectives for the development and design of pesticides,offering valuable insights for researchers in the field.
基金supported by the National Magnetic Con-finement Fusion Energy Research Project from the Ministry of Science and Technology of China(No.2022YFE03030004 and 2019YFE03120003)the National Natural Science Foundation of China(No.12275010,12275176,12275001,12335017,11921006,U21B2082,U22B2064 and U20B2025)+3 种基金the Beijing Municipal Natural Science Foundation(No.1222023)the Shenzhen Science and Technology Program(No.RCYX20210609103904028)Engang Fu acknowledges the support from the Science Fund or Creative Research Groups of NSFC,the Ion Beam Materials Laboratory(IBML)and Electron Microscopy Laboratory(EML)the High-performance Computing Platform(HPC)at Peking University.Xing Liu acknowledges the discussion with Prof.Ning Gao and Dr.Yifan Zhang.
文摘This study reports the response of helium(He)ion irradiation on binary-phase structured alloy V_(34)Ti_(25)Cr_(10)Ni_(30)Pd1.The alloy consists of a VCr matrix with nano-sized TiNi precipitates and a B2 TiNi matrix with nano-sized VCr precipitates.VCr is chemical-disordered and TiNi has a B2-ordered structure.The alloy was subjected to 400 keV He ion irradiation with a fluence of 1×10^(17)ions cm^(−2)at 450℃.The results show He bubbles within the chemical-disordered VCr matrix exhibit a near-spherical shape with a smaller size and higher density compared to that in chemical-ordered TiNi phase with a larger size,lower density,and faceted shape.This indicates the chemical-disordered VCr phase effectively suppresses He accumulation compared to the B2-ordered TiNi phase,emphasizing the dominance of chemical struc-tures in He bubble formation.The calculation of density functional theory(DFT)shows that Ti and Ni have lower vacancy formation energy than that of V and Cr,respectively,which results in the increased vacancy production in TiNi.Consequently,He bubbles in TiNi have a larger bubble size consistent with experimental observations of radiation-induced Ni segregation.These findings elucidate the roles of or-dered and disordered chemical structures in He bubble evolution,offering insights for the development of gas ion irradiation-resistant materials.
文摘Facial amphiphilicity is an extraordinary chemical structure feature of a variety of antimicrobial peptides and polymers.Vast efforts have been dedicated to small molecular,macromolecular and dendrimer-like systems to mimic this highly preferred structure or conformation,including local facial amphiphilicity and global amphiphilicity.This work conceptualizes Facial Amphiphilicity Index(FAI)as a numerical value to quantitatively characterize the measure of chemical compositions and structural features in dictating antimicrobial efficacy.FAI is a ratio of numbers of charges to rings,representing both compositions of hydrophilicity and hydrophobicity.Cationic derivatives of multicyclic compounds were evaluated as model systems for testing antimicrobial selectivity against Gram-negative and Gram-positive bacteria.Both monocyclic and bicyclic compounds are non-antimicrobial regardless of FAIs.Antimicrobial efficacy was observed with systems having larger cross-sectional areas including tricyclic abietic acid and tetracyclic bile acid.While low and high FAIs respectively lead to higher and lower antimicrobial efficacy,in consideration of cytotoxicity,the sweet spot is typically suited with intermediate FAIs for each specific system.This can be well explained by the synergistic hydrophobic-hydrophobic and electrostatic interactions with bacterial cell membranes and the difference between bacterial and mammalian cell membranes.The adoption of FAI would pave a new avenue toward the design of next-generation antimicrobial macromolecules and peptides.
基金founded by the National Natural Science Foundation of China(No.42022010)the National Key Research and Development Program of China(No.2022YFF0800100)the CAS Interdisciplinary Innovation Team(No.JCTD-2020-18)and the Youth Innovation Promotion Association.
文摘The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)coupled with energy-dispersive X-ray spectroscopy(EDS),offers valuable structural and chemical information for the analysis of fossils.However,its primary limitation is the restriction to two-dimensional surface data,which limits the exploration of fossils’3D complexities.Conversely,3D X-ray microscopy(3D-XRM),also known as a novel form of micro-computed tomography(micro-CT)facilitates the non-destructive 3D reconstruction of fossil specimens.Nevertheless,it lacks the capability to provide in-situ compositional data.Acknowledging the constraints inherent in these individual techniques,and in response to the evolving requirements of paleontological research,this study introduces an integrated approach that combines 3D-XRM with EDS-coupled focused ion beam scanning electron microscopy(FIB-SEM).This innovative strategy is designed to synergize the advantages of both techniques,thereby addressing challenges that conventional methods cannot.It enables the rapid identification of regions of interest(ROI)within fossil specimens at micrometer resolution.Subsequently,this method collects detailed data on both 3D structures and chemical compositions at the nanometer scale for the identified ROI.This integrated approach represents a significant advancement in paleontological and geological research methodologies,promising to meet the increasing demands of these fields.
基金National Natural Science Foundation ofChina,Grant/Award Number:52275212Fundamental Research Funds for theCentral Universities,Grant/Award Number:D5000230047the"Special Lubrication and Sealing forAerospace"Shaanxi Provincial Scienceand Technology Innovation Team,Grant/Award Number:2024RS-CXTD-63。
文摘MAX phase ceramics is a large family of nanolaminate carbides and nitrides,which integrates the advantages of both metals and ceramics,in general,the distinct chemical inertness of ceramics and excellent physical properties like metals.Meanwhile,the rich chemical and structural diversity of the MAXs endows them with broad space for property regulation.Especially,a much higher self-lubricity,as well as wear resistance,than that of traditional alloys and ceramics,has been observed in MAXs at elevated temperatures in recent decades,which manifests a great application potential and sparks tremendous research interest.Aiming at establishing a correlation among structure,chemical composition,working conditions,and the tribological behaviors of MAXs,this work overviews the recent progress in their high-temperature(HT)tribological properties,accompanied by advances in synthesis and structure analysis.HT tribological-specific behaviors,including the stress responses and damage mechanism,oxidation mechanism,and wear mechanism,are discussed.Whereafter,the tribological behaviors along with factors related to the tribological working conditions are discussed.Accordingly,outlooks of MAX phase ceramics for future HT solid lubricants are given based on the optimization of present mechanical properties and processing technologies.
基金supported by the Key R&D Program of Shandong Province,China(2023CXGC010611)the State Key Project of International Cooperation Research(2023YFE0201100)the Program for Introducing Talents of Discipline to Universities(“111”plan),and the High-Level Discipline Program of Shandong Province of China.
文摘With the increase of energy consumption,the shortage of fossil resource,and the aggravation of environmental pollution,the development of cost-effective and environmental friendly bio-based energy storage devices has become an urgent need.As the second most abundant natural polymer found in nature,lignin is mainly produced as the by-product of paper pulping and bio-refining industries.It possesses several inherent advantages,such as low-cost,high carbon content,abundant functional groups,and bio-renewable,making it an attractive candidate for the rechargeable battery material.Consequently,there has been a surge of research interest in utilizing lignin or lignin-based carbon materials as the components of lithium-ion(LIBs)or sodium-ion batteries(SIBs),including the electrode,binder,separator,and electrolyte.This review provides a comprehensive overview on the research progress of lignin-derived materials used in LIBs/SIBs,especially the application of lignin-based carbons as the anodes of LIBs/SIBs.The preparation methods and properties of lignin-derived materials with different dimensions are systemically discussed,which emphasizes on the relationship between the chemical/physical structures of lignin-derived materials and the performances of LIBs/SIBs.The current challenges and future prospects of lignin-derived materials in energy storage devices are also proposed.
基金National Natural Science Foundation of China,Grant/Award Numbers:32171717,32271814Natural Science Foundation of Tianjin Municipality,Grant/Award Numbers:24JCJQJC00030,22JCYBJC01560,23JCZDJC00630China Postdoctoral Science Foundation,Grant/Award Number:2023M740562。
文摘Carbon fibers(CFs)with notable comprehensive properties,such as light weight,high specific strength,and stiffness,have garnered considerable interest in both academic and industrial fields due to their diverse and advanced applications.However,the commonly utilized precursors,such as polyacrylonitrile and pitch,exhibit a lack of environmental sustainability,and their costs are heavily reliant on fluctuating petroleum prices.To meet the substantial market demand for CFs,significant efforts have been made to develop cost-effective and sustainable CFs derived from biomass.Lignin,the most abundant polyphenolic compound in nature,is emerging as a promising precursor which is well-suited for the production of CFs due to its renewable nature,low cost,high carbon content,and aromatic structures.Nevertheless,the majority of lignin raw materials are currently derived from pulping and biorefining industrial by-products,which are diverse and heterogeneous in nature,restricting the industrialization of lignin-derived CFs.This review classifies fossil-derived and biomass-derived CFs,starting from the sources and chemical structures of raw lignin,and outlines the preparation methods linked to the performance of lignin-derived CFs.A comprehensive discussion is presented on the relationship between the structural characteristics of lignin,spinning preparation,and structure-morphology-property of ligninderived CFs.Additionally,the potential applications of these materials in various domains,including energy,catalysis,composites,and other advanced products,are also described with the objective of spotlighting the unique merits of lignin.Finally,the current challenges faced and future prospects for the advancement of lignin-derived CFs are proposed.
基金supported by the National Natural Science Foundation of China(Grant No.51706160)Natural Science Foundation of Wuhan(2024040701010057)+2 种基金Hubei Technological Innovation Special Fund(Grant Nos.2023AFA004,2023BCB106,and 2022BCA085)14th“Five-Year Plan’’Hubei Provincial Advantaged Characteristic Disciplines Project of Wuhan University of Science and Technology(2023C0108)Foundation of Hubei Key Laboratory of Industrial Fume&Dust Pollution Control(HBIK2020-02).
文摘Forestry waste(FW)is a significant renewable energy source in China.The substitution of coal blends(BC)with forestry waste to produce metallurgical coke was investigated aiming at expanding alternative resources and reducing CO_(2)emissions in ironmaking process.The BC with different ratios of FW were carbonized in a fixed bed reactor,and the physicochemical structure of the coke derived from FW/BC co-carbonization was characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,solid-state^(13)C nuclear magnetic resonance,optical microscopy,and scanning electron microscopy.The results reveal that the suitable incorporation of FW in BC is 10 wt.%,and the index of coke quality exhibits a good correlation with the optical anisotropy index and the aromaticity of the as-obtained cokes.The partial substitution of BC with FW exhibits potential benefits for colloid formation,owing to the higher hydrogen in FW.However,as the substitution ratio of BC with FW increases,it inhibits coke agglomeration due to more tortuous stacked structures formation during volatile releasing process.Moreover,it was identified that the substitution of higher BC ratios with FW results in the partial replacement of aromatic carbons by oxygenlinked carbons and aliphatic carbons.This substitution leads to a reduction in the aromaticity of the as-obtained coke.
基金supported by the National Natural Science Foundation of China(Nos.42207371 and 32071642)the Scientific Project of Jiangsu Vocational College of Agriculture and Forestry,China(No.2021kj17)the Key Research Projects of Jiangsu Vocational College of Agriculture and Forestry,China(No.2023kj14)。
文摘Green prevention and control management of soil-borne fungal diseases is a hot topic in agriculture,ecology,and the environment.It is an important way to effectively prevent and control soil-borne fungal diseases,solve soil degradation caused by continuous cropping obstacles,and fulfill the sustainable development of agriculture through revealing the mechanisms of functional substances to develop highly effective soil amendments.Humic acid shows an inhibitory effect on soil-borne pathogenic fungi,such as Fusarium oxysporum,Choanephora cucurbitarum,and Rhizoctonia solani,with the inhibition rate exceeding 80%.The molecular and elemental composition and contents of–COOH,phenolic C,methoxy group C,carboxyl C,aromatic C–O,anomeric C,and other functional groups of humic acid have been inferred to be responsible for its inhibitory effects on pathogenic fungi in previous research.The inhibitory mechanisms mainly include cell physiological morphology,biochemical process reactions,and molecular signal transduction.This review systematically summarizes the chemical structure,fungistatic effects,variable characteristics,and inhibitory mechanisms of humic acid,aiming to provide a theoretical basis for the development of green and efficient prevention and control technologies for soil-borne fungal diseases.
基金supported by the National Natural Science Foundation for Distinguished Young Scholars(No.81725021)the National Natural Science Foundation of China(Nos.82003633,32100321,and 32300335)+1 种基金the National Natural Science Foundation of Hubei Province(Nos.2023AFB791 and 2023AFB530)the Knowledge Innovation Project of Wuhan Science and Technology Bureau(No.2023020201020534).
文摘Polycyclic polyprenylated acylphloroglucinols(PPAPs)represent a distinct subclass of specialized metabolites predominantly found in the plant kingdom,particularly within the Guttiferae(Clusiaceae)family.These compounds exhibit remarkable structural diversity and a wide range of biological activities.Seco-and nor-PPAPs,two unique variants of PPAPs with diverse skeletal structures,have been extensively investigated.As of June 2023,200 compounds have been isolated from four genera,with Hypericum being the primary source.Notably,115 of these compounds were identified in the past four years,indicating a significant increase in research activity.Seco-and nor-PPAPs can be categorized into six main subgroups based on the original PPAP scaffolds.Biological studies have revealed their potential in various therapeutic applications,including anti-cancer,anti-inflammatory,hepatoprotective,anti-Alzheimer’s disease(anti-AD),multidrug resistance(MDR)reversal,anti-depressant,neuroprotective,and immunosuppressive effects.This review provides a comprehensive overview of the occurrence,structures,and bioactivities of natural seco-and nor-PPAPs,offering valuable insights for the further development of PPAPs.
基金support from the Scientific Research Fund of Zhejiang Provincial Education Department(Y202353855)the Zhejiang Provincial Key R&D Project(2021C01056)+1 种基金the Programme of Introducing Talents of Discipline to Universities(No.D17008)the National Natural Science Foundation of China(22208312).
文摘Three large π-conjugated and imine-based COFs,named TFP-TAB,TFP-TTA,and TTA-TTB,were synthesized via the ordered incorporation of benzene and triazine rings in the same host framework to study how the structural units affect the efficiency of CO_(2)photoreduction.Results from both experiments and density-functional theory(DFT)calculations indicate the separation and transfer of the photoinduced charges is highly related to the triazine-N content and the conjugation degree in the skeletons of COFs.High-efficiency CO_(2)photoreduction can be achieved by rationally adjusting the number and position of both benzene and triazine rings in the COFs.Specifically,TTA-TTB,with orderly interlaced triazine-benzene heterojunctions,can suppress the recombination probability of electrons and holes,which effectively immobilizes the key species(COOH)and lowers the free energy change of the potential-determining step,and thus exhibits a superior visible-light-induced photocatalytic activity that yields 121.7 μmol HCOOH g^(-1)h^(-1).This research,therefore,helps to elucidate the effects of the different structural blocks in COFs on inherent heterogeneous photocatalysis for CO_(2)reduction at a molecular level.
基金supported by the National Natural Science Foundation of China(No.41806182)the National Key R&D Program of China(No.2020YFD0900900)+1 种基金the Provincial Universities Basic Scientific Research Foundation in Zhejiang Province of China(No.2021ZJ004)the Science and Technology Project of Zhoushan(No.2020C21020).
文摘Swimming crab(Portunus trituberculatus)eggs contain abundant phospholipids and polyunsaturated fatty acids with specific bioactivities.However,more studies on the functions of other nutrients are needed.Here,a novel sialoglycopeptide from P.trituberculatus eggs,which was termed as Pt-SGP,was isolated with enzymolysis.Pt-SGP was a 6480-Da pure sialoglycopeptide.O-glycan units existed between peptides and sugars.Pt-SGP was composed of 10.69%protein,71.43%hexose,and 11.27%Neu5Gc acid.Analyzed with HPLC,GC-MS,and NMR spectrometry,the carbohydrate chain of Pt-SGP was{(4GlcNAc1-2Man1-3)/(4GlcNAc1-2Man1-6)Man1-6}/{4Glc1-4}Glc1-4Glc1-3GlcNAc1.The MS spectrometry analysis result showed that the peptide chain was Val-Ala-Thr*-Val-Ser*-Leu-Pro-Arg.The results on mice showed Pt-SGP could reduce body weight gain by 18.13%,white adipose weight by 28.57%,serum TC by 22.32,serum TG by 9.46%,serum LDL-C by 27.69%,hepatic TC by 73.21%,and hepatic TG by 25.20%.Furthernore,it could increase serum HDL-C by 75.96%,mitigate adipocyte size and hepatic lipid accumulation in high fat diet-fed mice.Pt-SGP significantly down-regulated C/EBPαsignaling and up-regulated AMPKαsignaling in the epididymal fat tissues.The findings indicate that Pt-SGP exhibits notable anti-obesity properties,and can potentially become a promising dietary supplement for anti-obesity.
文摘Visible light photocatalytic redox catalysis has become a powerful tool for organic synthesis, and has opened up new avenues for the formation of challenging structural skeletons and chemical bonds. In this respect, diverse photocatalysts, including ruthenium(II), iridium(Ⅲ), and organic dyes, have been most commonly applied.
文摘The current paper reviews the content and variation of fiber fractions in feed ingredients commonly used in swine diets.Carbohydrates serve as the main source of energy in diets fed to pigs.Carbohydrates may be classified according to their degree of polymerization:monosaccharides,disaccharides,oligosaccharides,and polysaccharides.Digestible carbohydrates include sugars,digestible starch,and glycogen that may be digested by enzymes secreted in the gastrointestinal tract of the pig.Non-digestible carbohydrates,also known as fiber,may be fermented by microbial populations along the gastrointestinal tract to synthesize short-chain fatty acids that may be absorbed and metabolized by the pig.These non-digestible carbohydrates include two disaccharides,oligosaccharides,resistant starch,and non-starch polysaccharides.The concentration and structure of non-digestible carbohydrates in diets fed to pigs depend on the type of feed ingredients that are included in the mixed diet.Cellulose,arabinoxylans,and mixed linkedβ-(1,3)(1,4)-D-glucans are the main cell wall polysaccharides in cereal grains,but vary in proportion and structure depending on the grain and tissue within the grain.Cell walls of oilseeds,oilseed meals,and pulse crops contain cellulose,pectic polysaccharides,lignin,and xyloglucans.Pulse crops and legumes also contain significant quantities of galacto-oligosaccharides including raffinose,stachyose,and verbascose.Overall,understanding the structure,characteristics and measurable chemical properties of fiber in feed ingredients may result in more accurate diet formulations,resulting in an improvement in the utilization of energy from less expensive high-fiber ingredients and a reduction in reliance on energy from more costly cereal grains.
文摘The effect of different kinds of comonomers with or without flexible chain on properties of copolyesters, such as transition temperature, crystallization velocity, crystallinity and size Of crystallites, is studied. The experimental results indicate the obvious difference in properties between comonomers with iso-and ortho-structure of phenyl ring and comonomers with flexible chain. The influence of chemical structure of comonomers on properties of copolyesters is discussed.
基金supported by the National Natural Science Foundation of China (51536002)the Fundamental Research Funds for the Central Universities (2015QNA12)the Open Sharing Fund for the Large-scale Instruments and Equipments of China University of Mining and Technology (CUMT).
文摘The critical issue in developing mature Oxy-Coal Combustion Steam System technology could be the reactivity of deminer-alized coal which,is closely related to its chemical structure.The chemical structures of Liupanshui raw coal(LPS-R)and Liupanshui demineralized coal(LPS-D)were analyzed by FTIR and solid-state 13C-NMR.The pyrolysis experiments were carried out by TG,and the pyrolysis kinetics was analyzed by three iso-conversional methods.FTIR and 13C-NMR results suggested that the carbon structure of LPS coal was not altered greatly,while demineralization promoted the maturity of coal and the condensation degree of the aromatic ring,making the chemical structure of coal more stable.The oxygen-containing functional groups with low bond energy were reduced,and the ratio of aromatic carbon with high bond energy was increased,decreasing the pyrolysis reactivity.DTG curve-fitting results revealed that the thermal weight loss of LPS coal mainly came from the cleavage of aliphatic covalent bonds.By pyrolysis kinetics analysis of LPS-R and LPS-D,the apparent activation energies were 76±4 to 463±5 kJ/mol and 84±2 to 758±12 kJ/mol,respectively,under different conversion rates.The reactivity of the demineralized coal was inhibited to some extent,as the apparent activation energy of pyrolysis for LPS-D increased by acid treatment.
