Disturbance observer-based control method has achieved good results in the carfollowing scenario of intelligent and connected vehicle(ICV).However,the gain of conventional extended disturbance observer(EDO)-based cont...Disturbance observer-based control method has achieved good results in the carfollowing scenario of intelligent and connected vehicle(ICV).However,the gain of conventional extended disturbance observer(EDO)-based control method is usually set manually rather than adjusted adaptively according to real time traffic conditions,thus declining the car-following performance.To solve this problem,a car-following strategy of ICV using EDO adjusted by reinforcement learning is proposed.Different from the conventional method,the gain of proposed strategy can be adjusted by reinforcement learning to improve its estimation accuracy.Since the“equivalent disturbance”can be compensated by EDO to a great extent,the disturbance rejection ability of the carfollowing method will be improved significantly.Both Lyapunov approach and numerical simulations are carried out to verify the effectiveness of the proposed method.展开更多
The effect of lignin structural units on enzymatic hydrolysis of lignocellulosic biomass was investigated,especially the inhibitory role of lignin in non-productive adsorption with enzymes.Milled wood lignin(MWL)was i...The effect of lignin structural units on enzymatic hydrolysis of lignocellulosic biomass was investigated,especially the inhibitory role of lignin in non-productive adsorption with enzymes.Milled wood lignin(MWL)was isolated from different hardwoods of poplar,eucalyptus and acacia.The isolated lignin samples were characterized by elemental analysis,gel permeation chromatography,nitrobenzene oxidation and fourier infrared spectroscopy.The mechanism of lignin structural units on enzymatic hydrolysis of cellulose was studied by quartz crystal microbalance(QCM).The results showed that different structural units of lignin had different adsorption capacity for enzymes.The results of nitrobenzene oxidation indicated that the S/G ratio(S:syringyl-like lignin structures;G:guaiacyl-like lignin structures)of lignin of poplar was 0.99,that of eucalyptus was 1.92 and that of acacia was 1.34.According to the results of QCM,the adsorption capacity of the three lignin films was as follows:Poplar MWL(S/G ratio 0.99)<Acacia MWL(S/G ratio 1.34)<Eucalyptus MWL(S/G ratio 1.92).Eucalyptus MWL with higher degree of condensation and S/G ratio showed stronger affinity to enzymes and more non-productive adsorption with enzymes,resulting in less adsorption between enzymes and cellulose,and lower enzymatic hydrolysis efficiency.展开更多
Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be...Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc.展开更多
The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control.However,little is known about the coordinated regulation of leaf developmen...The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control.However,little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants.Here,we reported that TCP TFs are involved in both catechin biosynthesis and leaf development.An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production.CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat(MBW)complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase(CsANSl)and anthocyanidin reductase(CsANRl).Four types of microRNA/target modules,miR319b/CsTCP3-4,miR164b/CsCUC,miR396/CsGRF-GIF,and miR165b/HD-ZIPIII ones,were also identified and characterized for their functions in the regulation of the development of teaplant shoot tips and leaf shape.The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different teaplant varieties.Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b(miR319b),which targets the transcripts of CsTCP3 and CsTCP4.Thus,CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis.Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.展开更多
Protein-protein interactions are vital for a wide range of biological processes.The interactions between the hypoxia-inducible factor and von Hippel Lindau(VHL)are attractive drug targets for ischemic heart disease.In...Protein-protein interactions are vital for a wide range of biological processes.The interactions between the hypoxia-inducible factor and von Hippel Lindau(VHL)are attractive drug targets for ischemic heart disease.In order to disrupt this interaction,the strategy to target VHL binding site using a hydroxyproline-like(pro-like)small molecule has been reported.In this study,we focused on the inhibition mechanism between the pro-like inhibitors and the VHL protein,which were investigated via molecular dynamics simulations and binding free energy calculations.It was found that pro-like inhibitors showed a strong binding affinity toward VHL.Binding free energy calculations and free energy decompositions suggested that the modification of various regions of pro-like inhibitors may provide useful information for future drug design.展开更多
Lignocellulose is the main component of plants and has a wide range of sources.The high-value production of lignocellulose lies in the biorefinery of lignin,cellulose and hemicellulose.The ad-vantages and disadvantage...Lignocellulose is the main component of plants and has a wide range of sources.The high-value production of lignocellulose lies in the biorefinery of lignin,cellulose and hemicellulose.The ad-vantages and disadvantages of traditional lignocellulose pretreatment methods were summarized,and the effective pretreatment parameters were listed.As a green solvent system with excellent performance,deep eutectic solvents(DES)are considered to be the most potential biomass pre-treatment system.Based on this,the new trend and progress of DES in lignocellulose pretreatment were reviewed,focusing on the effects of distinct kinds of lignocellulose raw materials,distinct components of DES,distinct reaction conditions and assisted by microwave ultrasound on the pre-treatment of lignocellulose,and the recyclability of DES solution system was discussed.Finally,the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.展开更多
The WRKY gene family is most widely known as being the key plant transcription factor family involved in various stress responses and affecting plant growth and development.In this study,a total of 86 members of the C...The WRKY gene family is most widely known as being the key plant transcription factor family involved in various stress responses and affecting plant growth and development.In this study,a total of 86 members of the CsWRKY genes were identified from the tea plant genome.Most of these genes contain several important Cis-regulatory elements in the promoter regions associated with multiple stress-responses.These genes were further classified into three groups,I,II,and III,each with 21,58,and 7 members,respectively.We showed evidence that tandem duplications,but not the whole genome duplication,are likely to drive the amplification of CsWRKY genes in tea plants.All the 86 CsWRKY genes showed differential expression patterns either in different tissues,or under exposure to diverse abiotic stresses such as drought,cold acclimation,and MeJA treatments.Additionally,the functional roles of two genes,CsWRKY29 and CsWRKY37,were examined under cold stress;and the silencing of these genes resulted in tea plant phenotypes susceptible to cold stress.Moreover,transgenic Arabidopsis lines overexpressing CsWRKY29 and CsWRKY37 genes showed higher survival rates and lower malondialdehyde levels under freezing treatment than the wild type plants.The core findings from this work provide valuable evolutionary pattern of WRKY gene family and underpinning the underlying regulatory roles of CsWRKY29 and CsWRKY37 from tea plants that conferred cold tolerance in transgenic Arabidopsis plants.展开更多
Airborne particulate matter(PM),especially PM2.5,can be easily adsorbed by human respiratory system.Their roles in carrying pathogens for spreading epidemic diseases has attracted great concern.Herein,we developed a n...Airborne particulate matter(PM),especially PM2.5,can be easily adsorbed by human respiratory system.Their roles in carrying pathogens for spreading epidemic diseases has attracted great concern.Herein,we developed a novel gelatin filter-based and culture-independent method for investigation of the microbial diversity in PM samples during a haze episode in Tianjin,China.This method involves particle capture by gelatin filters,filter dissolution for DNA extraction,and high-throughput sequencing for analysis of the microbial diversity.A total of 584 operational taxonomic units(OTUs)of bacteria and 370 OTUs of fungi at the genus level were identified during hazy days.The results showed that both bacterial and fungal diversities could be evaluated by this method.This study provides a convenient strategy for investigation of microbial biodiversity in haze,facilitating accurate evaluation of airborne epidemic diseases.展开更多
Tea trichomes contribute significantly to tea flavors by providing diverse and specific flavor-determining metabolites,including catechins,caffeine,theanine,and volatiles.However,not much is known about the physiologi...Tea trichomes contribute significantly to tea flavors by providing diverse and specific flavor-determining metabolites,including catechins,caffeine,theanine,and volatiles.However,not much is known about the physiological functions of tea trichomes in tea plant adaptation to complex environments,nor the trichome development.Tea trichomes not only build up chemical defenses,but also act as the first physical barrier protecting herbivore attacks,reflecting high light and UV-B radiation,and preventing water loss.Moreover,transcriptome profiling on the tea trichomes compared with the trichome-removed leaves also showed that tea trichomes highly expressed numerous defense-related genes involved in protection from high light and UV-B radiation,cold stress,disease resistance signal transduction,anti-herbivore or anti-abiotic peptide biosynthesis,and other defense responses.Several pieces of experimental evidence supported the notes,highlighting the roles of tea trichomes in plant defenses against both abiotic and biotic stresses.The study provides fresh insights into the multiple protective functions of tea trichome for tea plant adaptation to harsh environments.The new understanding on tea trichomes could benefit the development of better breading strategy for new tea varieties with greater adaption and tolerance to changing environmental challenges.展开更多
Dissolved organic matter （DOM） plays an important role in biogeochemical cycles in aquatic ecosystem. To investigate the characteristics of DOM in Huangpu River {the last tributary of the Yangtze River）, surface wa...Dissolved organic matter （DOM） plays an important role in biogeochemical cycles in aquatic ecosystem. To investigate the characteristics of DOM in Huangpu River {the last tributary of the Yangtze River）, surface water samples were collected along the river from December 2011 to June, 2013. The concentrations of dissolved organic carbon （DOC）, the absorbance and fluorescence spectrum of DOM in water samples were measured. Fluorescent DOM in the Huangpu River was decomposed into four components by the parallel factor analysis （PARAFAC）, including one humic-like substance and three protein-like substances. It showed that high spatial variability of DOC concentration was observed in the upstream water compared to the downstream water, and so did the absorbance coefficients of chromophoric dissolved organic matter and the total fluorescence intensities of different PARAFAC components of DOM. Furthermore, there was a large difference between the polarity and bioavailability of DOM in the Huangpu River. Polar compounds dominated tyrosine-like component of fluorescent DOM in all seasons. Tryptophan-like and humic-like substances had more polar fraction in summer and autumn than those in winter, while aromatic protein-like materials had the highest polar fraction in winter. Almost all of fluorescent DOM components were refractory in spring, while less than 20% of fluorescent DOM in average were biodegradable within 4 weeks in other seasons. We concluded that the spatial variation in the abundance of DOM in the Huangpu River is mainly affected by the water discharges from the Hangjiahu Plain and the seasonal difference in polarity and bioavailability of DOM is largely determined by its origins.展开更多
Tick-borne encephalitis virus(TBEV) is a pathogenic virus known to cause central nervous system(CNS) diseases in humans, and has become an increasing public health threat nowadays. The rates of TBEV infection in the e...Tick-borne encephalitis virus(TBEV) is a pathogenic virus known to cause central nervous system(CNS) diseases in humans, and has become an increasing public health threat nowadays. The rates of TBEV infection in the endemic countries are increasing. However, there is no effective antiviral against the disease. This underscores the urgent need for tools to study the emergence and pathogenesis of TBEV and to accelerate the development of vaccines and antivirals. In this study, we reported an infectious c DNA clone of TBEV that was isolated in China(the WH2012 strain). A beta-globin intron was inserted in the coding region of nonstructural protein 1(NS1) gene to improve the stability of viral genome in bacteria. In mammalian cells, the inserted intron was excised and spliced precisely, which did not lead to the generation of inserted mutants. High titers of infectious progeny viruses were generated after the transfection of the infectious clone. The cDNA-derived TBEV replicated efficiently, and caused typical cytopathic effect(CPE) and plaques in BHK-21 cells. In addition, the CPE and growth curve of cDNA-derived virus were similar to that of its parental isolate in cells. Together, we have constructed the first infectious TBEV cDNA clone in China, and the clone can be used to investigate the genetic determinants of TBEV virulence and disease pathogenesis, and to develop countermeasures against the virus.展开更多
The interfacial wear between silicon and amorphous silica in water environment is critical in numerous applications.However,the understanding regarding the micro dynamic process is still unclear due to the limitations...The interfacial wear between silicon and amorphous silica in water environment is critical in numerous applications.However,the understanding regarding the micro dynamic process is still unclear due to the limitations of apparatus.Herein,reactive force field simulations are utilized to study the interfacial process between silicon and amorphous silica in water environment,exploring the removal and damage mechanism caused by pressure,velocity,and humidity.Moreover,the reasons for high removal rate under high pressure and high velocity are elucidated from an atomic perspective.Simulation results show that the substrate is highly passivated under high humidity,and the passivation layer could alleviate the contact between the abrasive and the substrate,thus reducing the damage and wear.In addition to more Si-O-Si bridge bonds formed between the abrasive and the substrate,new removal pathways such as multibridge bonds and chain removal appear under high pressure,which cause higher removal rate and severer damage.At a higher velocity,the abrasive can induce extended tribochemical reactions and form more interfacial Si-O-Si bridge bonds,hence increasing removal rate.These results reveal the internal cause of the discrepancy in damage and removal rate under different conditions from an atomic level.展开更多
Summary of main observation and conclusion Selective hydrogenation of a,B-unsaturated carbonyls into saturated carbonyls is important to obtain remunerative products.However,it is still a challenge to achieve high act...Summary of main observation and conclusion Selective hydrogenation of a,B-unsaturated carbonyls into saturated carbonyls is important to obtain remunerative products.However,it is still a challenge to achieve high activity and selec tivity under mild conditions.Herein,Pd,Ir and bimetallic Pd-Ir nanoparticles were uniformly deposited with high dispersity on the surface of SIC by a facile impregnation method,respectively.The as prepared Pd/SIC catalysts eficiently hydrogenate cinnamaldehyde to hydrocinnamaldehyde at room temperature and atmospheric pressure,and the activity of Pd/SiC is observed further enhanced by adding Ir component(conversion of 100%).In addition,the dependence of Pd-lr catalyst activity on Pd/Ir molar ratio con.firms a synergistic effect between Ir and Pd,which originates from the electron transfer between Pd and Ir.展开更多
Objectives:Dried ginger and ginger are the same type of medicine and food.The differential components of ginger and dried ginger,dried ginger and ginger charcoal were investigated.Materials and Methods:The experimenta...Objectives:Dried ginger and ginger are the same type of medicine and food.The differential components of ginger and dried ginger,dried ginger and ginger charcoal were investigated.Materials and Methods:The experimental materials were divided into three sample groups:the ginger group,dried ginger group,and ginger charcoal group.The ginger group,dried ginger group,and ginger charcoal group were qualitatively analyzed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.The data were processed by Marker View Software.Principal component analysis and orthogonal partial least-square discriminant analysis were performed with SIMCA 13.0 Software.The differential components of the ginger and dried ginger groups as well as the dried ginger and ginger charcoal groups with a variable importance in the projection>2(P<0.05)were identified with PeakView 1.2 Software.Results:Ten differential components,including 6-gingerol,8-gingerol,and 10-gingerol,were identified between the ginger group and dried ginger group;13 differential components,including 6-shogaol,10-gingerol,and zingiberone,were identified between the dried ginger group and ginger charcoal group.Conclusions:The main differential components between the ginger and dried ginger groups and the dried ginger and ginger charcoal groups were gingerols and diphenylheptanes.Based on metabolomics analysis of the chemical composition of ginger’s medicinal materials,effects,and other related factors,it is recommended that 6-gingerol,6-shogaol,and zingiberone should be used as indicative components for the respective quality evaluation of ginger,dried ginger and ginger charcoal.The results of this study may provide a basis for the reasonable quality evaluation of ginger medicinal materials.展开更多
As one of the important materials,nanocrystalline Au(n-Au)has gained numerous interests in recent decades owing to its unique properties and promising applications.However,most of the current n-Au thin films are suppo...As one of the important materials,nanocrystalline Au(n-Au)has gained numerous interests in recent decades owing to its unique properties and promising applications.However,most of the current n-Au thin films are supported on substrates,limiting the study on their mechanical properties and applications.Therefore,it is urgently desired to develop a new strategy to prepare nAu materials with superior mechanical strength and hardness.Here,a hard n-Au material with an average grain size of~40 nm is prepared by cold-forging of the unique Au nanoribbons(NRBs)with unconventional 4H phase under high pressure.Systematic characterizations reveal the phase transformation from 4H to face-centered cubic(fcc)phase during the cold compression.Impressively,the compressive yield strength and Vickers hardness(HV)of the prepared n-Au material reach~140.2 MPa and~1.0 GPa,which are 4.2 and 2.2 times of the microcrystalline Au foil,respectively.This work demonstrates that the combination of high-pressure cold-forging and the in-situ 4H-to-fcc phase transformation can effectively inhibit the grain growth in the obtained n-Au materials,leading to the formation of novel hard n-Au materials.Our strategy opens up a new avenue for the preparation of nanocrystalline metals with superior mechanical property.展开更多
基金State Key Laboratory of Automotive Safety and Energy,Grant/Award Number:KFY2208National Natural Science Foundation of China,Grant/Award Numbers:U2013601,U20A20225+1 种基金Key Research and Development Plan of Anhui Province,Grant/Award Number:202004a05020058the Natural Science Foundation of Hefei,China(Grant No.2021032)。
文摘Disturbance observer-based control method has achieved good results in the carfollowing scenario of intelligent and connected vehicle(ICV).However,the gain of conventional extended disturbance observer(EDO)-based control method is usually set manually rather than adjusted adaptively according to real time traffic conditions,thus declining the car-following performance.To solve this problem,a car-following strategy of ICV using EDO adjusted by reinforcement learning is proposed.Different from the conventional method,the gain of proposed strategy can be adjusted by reinforcement learning to improve its estimation accuracy.Since the“equivalent disturbance”can be compensated by EDO to a great extent,the disturbance rejection ability of the carfollowing method will be improved significantly.Both Lyapunov approach and numerical simulations are carried out to verify the effectiveness of the proposed method.
基金National Natural Science Foundation of China(31730106,21704045).
文摘The effect of lignin structural units on enzymatic hydrolysis of lignocellulosic biomass was investigated,especially the inhibitory role of lignin in non-productive adsorption with enzymes.Milled wood lignin(MWL)was isolated from different hardwoods of poplar,eucalyptus and acacia.The isolated lignin samples were characterized by elemental analysis,gel permeation chromatography,nitrobenzene oxidation and fourier infrared spectroscopy.The mechanism of lignin structural units on enzymatic hydrolysis of cellulose was studied by quartz crystal microbalance(QCM).The results showed that different structural units of lignin had different adsorption capacity for enzymes.The results of nitrobenzene oxidation indicated that the S/G ratio(S:syringyl-like lignin structures;G:guaiacyl-like lignin structures)of lignin of poplar was 0.99,that of eucalyptus was 1.92 and that of acacia was 1.34.According to the results of QCM,the adsorption capacity of the three lignin films was as follows:Poplar MWL(S/G ratio 0.99)<Acacia MWL(S/G ratio 1.34)<Eucalyptus MWL(S/G ratio 1.92).Eucalyptus MWL with higher degree of condensation and S/G ratio showed stronger affinity to enzymes and more non-productive adsorption with enzymes,resulting in less adsorption between enzymes and cellulose,and lower enzymatic hydrolysis efficiency.
基金This work was financially supported by the National Natural Science Foundation of China(31730106).
文摘Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc.
基金the Nati onal Key Resea rch and Development Program of China(2018YFD1000601)the Key Research and Development(R&D)Program of Anhui Province(18030701155)funding from An hui Agr icult ural Univer sity,and funding from the State Key Lab oratory of Tea Plant Biology and Utilization.
文摘The growth of leaves and biosynthesis of characteristic secondary metabolites are critically important for tea production and quality control.However,little is known about the coordinated regulation of leaf development and catechin biosynthesis in tea plants.Here,we reported that TCP TFs are involved in both catechin biosynthesis and leaf development.An integrated analysis of catechin profiling and CsTCP expression in different tissues of plants under various environmental conditions at different developmental stages indicated significant correlations between the transcript levels of CIN-type TCPs and catechin production.CIN-type CsTCP3 and CsTCP4 and PCF-type CsTCP14 interacted with the MYB-bHLH-WD40 repeat(MBW)complex by forming a CsTCP3-CsTT8 heterodimer and modulating the transactivation activity of the promoters of anthocyanin synthase(CsANSl)and anthocyanidin reductase(CsANRl).Four types of microRNA/target modules,miR319b/CsTCP3-4,miR164b/CsCUC,miR396/CsGRF-GIF,and miR165b/HD-ZIPIII ones,were also identified and characterized for their functions in the regulation of the development of teaplant shoot tips and leaf shape.The results of these modules were reflected by their different expression patterns in developing buds and leaves that had distinctly different morphologies in three different teaplant varieties.Their roles in the regulation of catechin biosynthesis were also further verified by manipulation of microRNA319b(miR319b),which targets the transcripts of CsTCP3 and CsTCP4.Thus,CsTCPs represent at least one of these important groups of TFs that can integrate tea plant leaf development together with secondary metabolite biosynthesis.Our study provides new insight into shoot tip development and catechin production in tea plants and lays a foundation for further mechanistic understanding of the regulation of tea plant leaf development and secondary metabolism.
基金supported by the National Natural Science Foundation of China(No.21973064)the Post-Doctor Research Project,West China Hospital,Sichuan University(No.2021HXBH017)。
文摘Protein-protein interactions are vital for a wide range of biological processes.The interactions between the hypoxia-inducible factor and von Hippel Lindau(VHL)are attractive drug targets for ischemic heart disease.In order to disrupt this interaction,the strategy to target VHL binding site using a hydroxyproline-like(pro-like)small molecule has been reported.In this study,we focused on the inhibition mechanism between the pro-like inhibitors and the VHL protein,which were investigated via molecular dynamics simulations and binding free energy calculations.It was found that pro-like inhibitors showed a strong binding affinity toward VHL.Binding free energy calculations and free energy decompositions suggested that the modification of various regions of pro-like inhibitors may provide useful information for future drug design.
基金the National Natural Science Foundation of China(No.31730106).
文摘Lignocellulose is the main component of plants and has a wide range of sources.The high-value production of lignocellulose lies in the biorefinery of lignin,cellulose and hemicellulose.The ad-vantages and disadvantages of traditional lignocellulose pretreatment methods were summarized,and the effective pretreatment parameters were listed.As a green solvent system with excellent performance,deep eutectic solvents(DES)are considered to be the most potential biomass pre-treatment system.Based on this,the new trend and progress of DES in lignocellulose pretreatment were reviewed,focusing on the effects of distinct kinds of lignocellulose raw materials,distinct components of DES,distinct reaction conditions and assisted by microwave ultrasound on the pre-treatment of lignocellulose,and the recyclability of DES solution system was discussed.Finally,the application and development direction of DES in lignocellulose pretreatment are proposed and prospected.
基金the National Natural Science Foundation of China(32172626)the Anhui Provincial Natural Science Foundation(2208085MC72,1908085MC75)the Anhui University Collaborative Innovation Project(GXXT-2020-080).
文摘The WRKY gene family is most widely known as being the key plant transcription factor family involved in various stress responses and affecting plant growth and development.In this study,a total of 86 members of the CsWRKY genes were identified from the tea plant genome.Most of these genes contain several important Cis-regulatory elements in the promoter regions associated with multiple stress-responses.These genes were further classified into three groups,I,II,and III,each with 21,58,and 7 members,respectively.We showed evidence that tandem duplications,but not the whole genome duplication,are likely to drive the amplification of CsWRKY genes in tea plants.All the 86 CsWRKY genes showed differential expression patterns either in different tissues,or under exposure to diverse abiotic stresses such as drought,cold acclimation,and MeJA treatments.Additionally,the functional roles of two genes,CsWRKY29 and CsWRKY37,were examined under cold stress;and the silencing of these genes resulted in tea plant phenotypes susceptible to cold stress.Moreover,transgenic Arabidopsis lines overexpressing CsWRKY29 and CsWRKY37 genes showed higher survival rates and lower malondialdehyde levels under freezing treatment than the wild type plants.The core findings from this work provide valuable evolutionary pattern of WRKY gene family and underpinning the underlying regulatory roles of CsWRKY29 and CsWRKY37 from tea plants that conferred cold tolerance in transgenic Arabidopsis plants.
基金supported by Project of Science and Technology Development in Wuqing District,Tianjin (No.WQKJ201614)Tianjin 131 innovative talent training project,Postdoctoral Science Foundation
文摘Airborne particulate matter(PM),especially PM2.5,can be easily adsorbed by human respiratory system.Their roles in carrying pathogens for spreading epidemic diseases has attracted great concern.Herein,we developed a novel gelatin filter-based and culture-independent method for investigation of the microbial diversity in PM samples during a haze episode in Tianjin,China.This method involves particle capture by gelatin filters,filter dissolution for DNA extraction,and high-throughput sequencing for analysis of the microbial diversity.A total of 584 operational taxonomic units(OTUs)of bacteria and 370 OTUs of fungi at the genus level were identified during hazy days.The results showed that both bacterial and fungal diversities could be evaluated by this method.This study provides a convenient strategy for investigation of microbial biodiversity in haze,facilitating accurate evaluation of airborne epidemic diseases.
基金the National Natural Science Foundation of China(32002089)the Anhui Provincial Natural Science Foundation(201902a05020408)+1 种基金the National Key Research and Development Program of China(2018YFD1000601)the funding from Anhui Agricultural University and the State Key Laboratory of Tea Plant Biology and Utilization.
文摘Tea trichomes contribute significantly to tea flavors by providing diverse and specific flavor-determining metabolites,including catechins,caffeine,theanine,and volatiles.However,not much is known about the physiological functions of tea trichomes in tea plant adaptation to complex environments,nor the trichome development.Tea trichomes not only build up chemical defenses,but also act as the first physical barrier protecting herbivore attacks,reflecting high light and UV-B radiation,and preventing water loss.Moreover,transcriptome profiling on the tea trichomes compared with the trichome-removed leaves also showed that tea trichomes highly expressed numerous defense-related genes involved in protection from high light and UV-B radiation,cold stress,disease resistance signal transduction,anti-herbivore or anti-abiotic peptide biosynthesis,and other defense responses.Several pieces of experimental evidence supported the notes,highlighting the roles of tea trichomes in plant defenses against both abiotic and biotic stresses.The study provides fresh insights into the multiple protective functions of tea trichome for tea plant adaptation to harsh environments.The new understanding on tea trichomes could benefit the development of better breading strategy for new tea varieties with greater adaption and tolerance to changing environmental challenges.
基金supported by the National Natural Science Foundation of China (Nos.41071301, 40601095)the Fundamental Research Funds for the Central Universities (No.0400219216)
文摘Dissolved organic matter （DOM） plays an important role in biogeochemical cycles in aquatic ecosystem. To investigate the characteristics of DOM in Huangpu River {the last tributary of the Yangtze River）, surface water samples were collected along the river from December 2011 to June, 2013. The concentrations of dissolved organic carbon （DOC）, the absorbance and fluorescence spectrum of DOM in water samples were measured. Fluorescent DOM in the Huangpu River was decomposed into four components by the parallel factor analysis （PARAFAC）, including one humic-like substance and three protein-like substances. It showed that high spatial variability of DOC concentration was observed in the upstream water compared to the downstream water, and so did the absorbance coefficients of chromophoric dissolved organic matter and the total fluorescence intensities of different PARAFAC components of DOM. Furthermore, there was a large difference between the polarity and bioavailability of DOM in the Huangpu River. Polar compounds dominated tyrosine-like component of fluorescent DOM in all seasons. Tryptophan-like and humic-like substances had more polar fraction in summer and autumn than those in winter, while aromatic protein-like materials had the highest polar fraction in winter. Almost all of fluorescent DOM components were refractory in spring, while less than 20% of fluorescent DOM in average were biodegradable within 4 weeks in other seasons. We concluded that the spatial variation in the abundance of DOM in the Huangpu River is mainly affected by the water discharges from the Hangjiahu Plain and the seasonal difference in polarity and bioavailability of DOM is largely determined by its origins.
基金This study was supported by grants from the National Key R&D Program of China(2018YFA0507201)。
文摘Tick-borne encephalitis virus(TBEV) is a pathogenic virus known to cause central nervous system(CNS) diseases in humans, and has become an increasing public health threat nowadays. The rates of TBEV infection in the endemic countries are increasing. However, there is no effective antiviral against the disease. This underscores the urgent need for tools to study the emergence and pathogenesis of TBEV and to accelerate the development of vaccines and antivirals. In this study, we reported an infectious c DNA clone of TBEV that was isolated in China(the WH2012 strain). A beta-globin intron was inserted in the coding region of nonstructural protein 1(NS1) gene to improve the stability of viral genome in bacteria. In mammalian cells, the inserted intron was excised and spliced precisely, which did not lead to the generation of inserted mutants. High titers of infectious progeny viruses were generated after the transfection of the infectious clone. The cDNA-derived TBEV replicated efficiently, and caused typical cytopathic effect(CPE) and plaques in BHK-21 cells. In addition, the CPE and growth curve of cDNA-derived virus were similar to that of its parental isolate in cells. Together, we have constructed the first infectious TBEV cDNA clone in China, and the clone can be used to investigate the genetic determinants of TBEV virulence and disease pathogenesis, and to develop countermeasures against the virus.
基金The authors greatly appreciate the National Major Science and Technology Projects of China(Grant No.51991372)the Natural Science Foundation of Liaoning Province,China(Grant No.2020-MS-120).
文摘The interfacial wear between silicon and amorphous silica in water environment is critical in numerous applications.However,the understanding regarding the micro dynamic process is still unclear due to the limitations of apparatus.Herein,reactive force field simulations are utilized to study the interfacial process between silicon and amorphous silica in water environment,exploring the removal and damage mechanism caused by pressure,velocity,and humidity.Moreover,the reasons for high removal rate under high pressure and high velocity are elucidated from an atomic perspective.Simulation results show that the substrate is highly passivated under high humidity,and the passivation layer could alleviate the contact between the abrasive and the substrate,thus reducing the damage and wear.In addition to more Si-O-Si bridge bonds formed between the abrasive and the substrate,new removal pathways such as multibridge bonds and chain removal appear under high pressure,which cause higher removal rate and severer damage.At a higher velocity,the abrasive can induce extended tribochemical reactions and form more interfacial Si-O-Si bridge bonds,hence increasing removal rate.These results reveal the internal cause of the discrepancy in damage and removal rate under different conditions from an atomic level.
基金This work is supportep by the National Natural Science Foun-dation of China(Nos.21473232,21673271 and U1710112).
文摘Summary of main observation and conclusion Selective hydrogenation of a,B-unsaturated carbonyls into saturated carbonyls is important to obtain remunerative products.However,it is still a challenge to achieve high activity and selec tivity under mild conditions.Herein,Pd,Ir and bimetallic Pd-Ir nanoparticles were uniformly deposited with high dispersity on the surface of SIC by a facile impregnation method,respectively.The as prepared Pd/SIC catalysts eficiently hydrogenate cinnamaldehyde to hydrocinnamaldehyde at room temperature and atmospheric pressure,and the activity of Pd/SiC is observed further enhanced by adding Ir component(conversion of 100%).In addition,the dependence of Pd-lr catalyst activity on Pd/Ir molar ratio con.firms a synergistic effect between Ir and Pd,which originates from the electron transfer between Pd and Ir.
基金the National Key Research and Development Project of China(2020YFC1712700)the National Chinese Medicine Standardization Project(ZYBZH-C-JS-34)the Special Technology System Project for the Modern Agricultural Industry(CARS-21),China.
文摘Objectives:Dried ginger and ginger are the same type of medicine and food.The differential components of ginger and dried ginger,dried ginger and ginger charcoal were investigated.Materials and Methods:The experimental materials were divided into three sample groups:the ginger group,dried ginger group,and ginger charcoal group.The ginger group,dried ginger group,and ginger charcoal group were qualitatively analyzed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.The data were processed by Marker View Software.Principal component analysis and orthogonal partial least-square discriminant analysis were performed with SIMCA 13.0 Software.The differential components of the ginger and dried ginger groups as well as the dried ginger and ginger charcoal groups with a variable importance in the projection>2(P<0.05)were identified with PeakView 1.2 Software.Results:Ten differential components,including 6-gingerol,8-gingerol,and 10-gingerol,were identified between the ginger group and dried ginger group;13 differential components,including 6-shogaol,10-gingerol,and zingiberone,were identified between the dried ginger group and ginger charcoal group.Conclusions:The main differential components between the ginger and dried ginger groups and the dried ginger and ginger charcoal groups were gingerols and diphenylheptanes.Based on metabolomics analysis of the chemical composition of ginger’s medicinal materials,effects,and other related factors,it is recommended that 6-gingerol,6-shogaol,and zingiberone should be used as indicative components for the respective quality evaluation of ginger,dried ginger and ginger charcoal.The results of this study may provide a basis for the reasonable quality evaluation of ginger medicinal materials.
基金supported by the National Natural Science Foundation of China(Nos.52090020,51722209,and 51525205)the National Key Research and Development Program of China(No.2018YFA0305900)+3 种基金Z.S.Z.acknowledges the NSF for Distinguished Young Scholars of Hebei Province of China(No.E2018203349)M.D.M.acknowledges the China Postdoctoral Science Foundation(No.2021M691051)Z.X.F.and H.Z.thank the support from ITC via Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM),the Start-Up Grants(Nos.9380100,9610480,and 7200651)grants(Nos.9610478,1886921,7020013,and 7005512)from City University of Hong Kong.
文摘As one of the important materials,nanocrystalline Au(n-Au)has gained numerous interests in recent decades owing to its unique properties and promising applications.However,most of the current n-Au thin films are supported on substrates,limiting the study on their mechanical properties and applications.Therefore,it is urgently desired to develop a new strategy to prepare nAu materials with superior mechanical strength and hardness.Here,a hard n-Au material with an average grain size of~40 nm is prepared by cold-forging of the unique Au nanoribbons(NRBs)with unconventional 4H phase under high pressure.Systematic characterizations reveal the phase transformation from 4H to face-centered cubic(fcc)phase during the cold compression.Impressively,the compressive yield strength and Vickers hardness(HV)of the prepared n-Au material reach~140.2 MPa and~1.0 GPa,which are 4.2 and 2.2 times of the microcrystalline Au foil,respectively.This work demonstrates that the combination of high-pressure cold-forging and the in-situ 4H-to-fcc phase transformation can effectively inhibit the grain growth in the obtained n-Au materials,leading to the formation of novel hard n-Au materials.Our strategy opens up a new avenue for the preparation of nanocrystalline metals with superior mechanical property.
