Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent n...Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent normal tissues.The relationship between CD151 expression and the clinicopathological characteristics of gastric cancer was analyzed.Results:The expression of CD151 in gastric cancer tissues was significantly higher than in adjacent normal tissues(P<0.05).It was associated with the degree of differentiation,depth of invasion,lymph node metastasis,and TNM staging of gastric cancer.The survival time of patients with high CD151 expression was significantly shorter than that of those with low expression(P<0.05).Conclusion:High expression of CD151 in gastric cancer tissues is correlated with the malignant biological behavior of gastric cancer and can serve as an indicator for evaluating the prognosis of gastric cancer.展开更多
Biomass production and nutrient (N, P, K, Ca and Mg) accumulation, distribution and cycling were quantified in young, mature and over-mature (10-, 22-, and 34-year old) Chinese fir [Cunninghamia lanceolate (Lamb....Biomass production and nutrient (N, P, K, Ca and Mg) accumulation, distribution and cycling were quantified in young, mature and over-mature (10-, 22-, and 34-year old) Chinese fir [Cunninghamia lanceolate (Lamb.) Hook] plantations in southern China. Total stand biomass of young, mature and over-mature stands was 38, 104 and 138 t ha-1 respectively. Biomass production increased significantly with age. Stem wood represented the highest percentage of stand biomass, accounting for 41, 55 and 63 % in the young, mature and over-mature plan- tations respectively. Nutrients concentration was highest in live needles and branches, and lowest in stem wood. The plantations accumulated more N, followed by K, Ca, Mg, and P. Nutrient return amount, nutrient utilization effi- ciency, nutrient turnover time, the ratio of nutrient return and uptake increased with stand age, which implies that young Chinese fir deplete soil nutrients to maintain growth, and efficiently utilize nutrients to decrease dependence on soil nutrients as they age. Harvesting young Chinese fir plantations would therefore lead to high nutrient loss, but prolonging the rotation length could improve soil recovery, and help sustain productivity in the long-term. Improved nutrient return through litterfall as stands get older may also be beneficial to nutrient pool recovery.展开更多
Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well.A mathematical model is developed to simulate flowing pressures and pressure drops ...Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well.A mathematical model is developed to simulate flowing pressures and pressure drops of CBM column from well head to bottom hole.The measured parameters and independent variables of flow rates,flowing pressures and temperatures are involved in CBM producing process along the annulus.The developed relationships are validated against full-scale measured data in single-phase CBM wellbores.The proposed methodology can analyze the dynamic behavior in CBM reservoir and process of CBM flow with an overall accuracy of 2%.The calculating process of flowing pressures involves friction factor with variable Reynolds number and CBM temperature and compressibility factor with gravitational gradients.The results showed that the effect of flowing pressure on CBM column was more obvious than that on CBM and water column accompanied by an increase of dynamic water level.The ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water column.Bottom-hole pressure declined with the decreased flowing pressure of CBM column along the annulus.It will lead to the results of the increased pressure drop of CBM column and CBM flow rate in single-phase CBM wellbores.展开更多
Data analysis on tokamak plasmas is mainly based on various diagnostic systems,which are usually modularized and independent of each other.This leads to a large amount of data not being fully and effectively exploited...Data analysis on tokamak plasmas is mainly based on various diagnostic systems,which are usually modularized and independent of each other.This leads to a large amount of data not being fully and effectively exploited so that it is not conducive to revealing the deep physical mechanism.In this work,Bayesian probability inference with machine learning methods have been applied to the electron cyclotron emission and Thomson scattering diagnostic systems on HL-2A/2M,and the effects of integrated data analysis(IDA)on the electron temperature of HL-2A with Bayesian probability inference are demonstrated.A program is developed to infer the whole electron temperature profile with a confidence interval,and the program can be applied in online analysis.The IDA results show that the full profile of the electron temperature can be obtained and the diagnostic information is more comprehensive and abundant with IDA.The inference models for electron temperature analysis are established and the developed programs will serve as an experimental data analysis tool for HL-2A/2M in the near future.展开更多
The residual resources of ramie fiber-based textile products were used as raw materials.Ramie fiber felt(RF)was modified by NaClO_(2) aqueous solution and then impregnated with water-based epoxy resin(WER).RF/WER tran...The residual resources of ramie fiber-based textile products were used as raw materials.Ramie fiber felt(RF)was modified by NaClO_(2) aqueous solution and then impregnated with water-based epoxy resin(WER).RF/WER transparent composite materials were prepared by lamination hot pressing process.The composite materials’color difference,transmittance,haze,density,water absorption,and mechanical properties were determined to assess the effects of NaClO_(2) treatment and the number of ramie fiber layers on the properties of the prepared composites.The results showed significantly improved optical and mechanical properties of the RF/WER transparent composites after NaClO_(2) treatment.With the increase of ramie fiber layers,the composites’whiteness,transmittance,and water absorption decreased while the haze increased.For material with three layers,the optical transmittance in the visible light region was 82%,and the haze was 96%,indicating the material has both high transmittance and high haze characteristics.The tensile strength increases with the increase of the number of layers,and the tensile strength of the composite with six layers is 243 MPa.This study broadens the scope of application of ramie fiber as a new option for home decoration materials.展开更多
CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve th...CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve the high-performance and high-reliability of electric machines while ensuring their cost-effectiveness.In motor design,with the advancements of optimization theory and technology,increasingly effective methods have been developed for the design of motors.展开更多
Aims Aquatic plants play an important role in freshwater ecosystems.Previous works have largely focused on the functional significance of plant above ground parts,with much less attention on the root structures of aqu...Aims Aquatic plants play an important role in freshwater ecosystems.Previous works have largely focused on the functional significance of plant above ground parts,with much less attention on the root structures of aquatic plants.In this study,we divided 21 aquatic plants(including five introduced plants)into multiple plant groups(different life forms,monocot/eudicot and introduced/native)with the goal of addressing two questions:(i)what root structures do aquatic plants exhibit,and(ii)are there differences among these plant groups?Methods Twenty-one aquatic plants belonging to four life forms(free-float-ing,emergent,floating-leaved and submerged)were collected at the near flowering stage from a typical macrophyte-dominated lake in the yangtze River Basin,China.The following root topological parameters were quantified:altitude(a),path length(pe),magnitude(M),mean topological length(b),topological index(TI)and normed indices qa and qb.Important Findings The root topological indices TI,qa and qb for the 21 aquatic plants were 0.724±0.013,0.290±0.031 and 0.152±0.024(means±S.E.),respectively,revealing a general pattern of dichotomous branching,except for the aquatic root of Myriophyllum aquati-cum(Vell.)Verdc.,which displays herringbone branching.All three topological indices were significantly lower for monocots(TI=0.700±0.130,qa=0.191±0.149 and qb=0.086±0.236)than eudicots(TI=0.752±0.206,qa=0.405±0.569 and qb=0.229±0.393),indicating that the roots of monocots are typi-cally more dichotomous-like than those of eudicots.Among the four life forms,the three topological indices for emergent plants(TI=0.832±0.006,qa=0.616±0.018 and qb=0.381±0.014)were significantly higher than those of the other three life forms.Overall,there was no difference between the topological indices of introduced and native aquatic plants,but the introduced species M.aquaticum and Alternanthera philoxeroides(Mart.)Griseb.had both aquatic and edaphic roots as well as unusual functions,which may help explain their strong viability.展开更多
Control strategies play a key role for operation of electric machines,which would directly affect the whole system performance.In fact,different control strategies have been executed and explored for electric machines...Control strategies play a key role for operation of electric machines,which would directly affect the whole system performance.In fact,different control strategies have been executed and explored for electric machines,which bring great impacts to industrial development and human society.This paper investigates and discusses the advantages control strategies for electric machines,including the field oriented control(FOC),direct torque control(DTC),finite control set model predictive control(FCS-MPC),sensorless control,and fault tolerant control(FTC).The corresponding control principles,control targets,fundamental approaches,advanced approaches,methodologies,merits and shortcomings are revealed and analyzed in detail.展开更多
The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 : 1 complexation of Zn^2+ and Cd^2+ ions with ditopic terpyridine ligand was reported. The dispersibility o...The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 : 1 complexation of Zn^2+ and Cd^2+ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer (ILCT) between the d^10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.展开更多
Amino acids are basic units to construct a protein with the assistance of various interactions.During this building process,steric hindrance derived from amino acid side groups or side chains is a factor that could no...Amino acids are basic units to construct a protein with the assistance of various interactions.During this building process,steric hindrance derived from amino acid side groups or side chains is a factor that could not be ignored.In this contribution,adsorption behaviors of C-terminal amino acid derivatives with amino acid residues fused in 3,4,9,10-perylenetetracarboxylic dianhydride were investigated by scanning tunneling microscopy(STM)and density functional theory(DFT)calculations at various liquid/solid interfaces.STM results at 1-phenyloctane/HOPG interface show that N,N'-3,4,9,10-perylenedicarboximide(GP)and N,N'-methyl-3,4,9,10-perylenedicarboximide(AP)formed linear and herringbone structures,respectively.The driving force could be attributed to different H-bonding sites induced by steric hindrance at side groups.N,N'-Benzyl-3,4,9,10-perylenedicarboximide(PP)generates both linear and herringbone structures because steric hindrance changes the H-bonding sites between PP molecules,whereas N,N'-isopropyl-3,4,9,10-perylenedicarboximide(LP)failed to be imaged because of strong steric hindrance coming from larger side group.To further investigate the impact of steric hindrance,we utilized octanoic acid(OA)as solvent to capture the adsorption details of LP and PP.We found that OA molecules drag PP and LP molecules in a different direction to generate linear structure,impeding the molecular rotation.The structure–solvent relationship shows that the steric hindrance is brought by the large side group,which makes it easier to recognize OA molecules at the interface.These results demonstrate that steric effect plays a significant role in altering interaction sites of the compounds during the adsorption process at the liquid/solid interface.展开更多
A stable,rapid and effective neural differentiation method is essential for the clinical applications of human embryonic stem cells(ESCs)or induced pluripotent stem cells(iPSCs)in treating neurological disorders and d...A stable,rapid and effective neural differentiation method is essential for the clinical applications of human embryonic stem cells(ESCs)or induced pluripotent stem cells(iPSCs)in treating neurological disorders and diseases.Herein,we established a novel and robust monolayer differentiation method to produce functional neural progenitor cells(NPCs)from human ESC/iPSCs on Type I Collagen.The derived cells not only displayed the requisite markers,but also behaved similarly to classic NPCs both in vitro and in vivo.Upon transplantation into traumatic brain injury model,the derived NPCs facilitated recovery from injury.We also found that SMAD signaling stayed down throughout the differentiation process on Type I Collagen,and the pluripotent signals were rapidly downregulated along with raising up of neural early markers on the third day.Meanwhile,ATAC-seq data showed the related mediation of distinct transcriptome and global chromatin dynamics during NPC induction.Totally,our results thus provide a convenient way to generate NPCs from human ESC/iPSCs for neural diseases’treatment.展开更多
Aims Environmental heterogeneity affects the performance of clonal aquatic plants.Few researchers integrated two aspects of heterogeneity into the study of clonal plant ecology.The aims of the present study are to(i)t...Aims Environmental heterogeneity affects the performance of clonal aquatic plants.Few researchers integrated two aspects of heterogeneity into the study of clonal plant ecology.The aims of the present study are to(i)test whether different substrate heterogeneity and submergence exert similar effects on plant performance and(ii)explore the foraging behaviour.Methods In this study,Scirpus yagara was subjected to multiple levels of substrate heterogeneity and submergence.Substrate treatments included one homogeneous substrate and three heterogeneous substrates(two-patch,four-patch and eight-patch).Water level treatments included 0,10 and 30 cm.Traits including ramet number,generation number,leaf number,bulb number,ramet height,culm length,rhizome length,clonal radius,spacer length,spacer thickness,total biomass,biomass of bulbs and biomass per bulb were measured.Important Findings Deeper water levels significantly reduced variables associated with growth such as ramet number,generation number,leaf number and bulb number,while substrate patchiness induced significant variations in traits such as spacer length and spacer thickness.Significant interactive effects of the two factors were found for ramet number,leaf number and spacer length.Scirpus yagara showed colonization towards the lake sediment patch in two-patch and four-patch substrates,and more structures were placed in the lake sediment patch.Especially for the two-patch substrate,all structures occupied the lake sediment patch.Two-sided intrusion was observed in the eight-patch substrate,which induced an even allocation of structures in different patches.The foraging behaviour was correlated with the patch size.展开更多
Clonal integration benefits clonal plants by buffering environmental stress and increasing resource extraction efficiency.However,the number of connected ramet generations that benefit from clonal integration in a clo...Clonal integration benefits clonal plants by buffering environmental stress and increasing resource extraction efficiency.However,the number of connected ramet generations that benefit from clonal integration in a clonal system has received relatively little attention.A pot experiment was conducted to evaluate the extent of physiological integration within the clonal system of Vallisneria natans consisting of a mother ramet and three sequentially connected offspring ramets.Mother ramets were grown in full sunlight,and offspring ramets were heavily shaded with limited light availability.Stolons between mother ramets and offspring ramets were severed or connected,but connection among the three offspring ramets remained.The photosynthetic ability of unshaded mother ramets of V.natans was significantly enhanced,but their biomass accumulation was greatly reduced when connected to shaded offspring ramets.Clonal integration significantly increased biomass accumulation,C and N availabilities,extracellular enzyme activities and microbial biomass of the first ramet generation(adjacent ramet),but not later ramet generations.Our results indicate that support from the mother ramet of V.natans may be limited to the adjacent offspring ramet in a clonal system under severe light stress,implying an effect of ramet generation.Our results contribute to a better understanding of the hierarchy and segmentation of clonal plants.These findings suggest that the extent of clonal integration plays a vital role in ecological interactions of the ramet population.展开更多
The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual tota...The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual total environmental impact was established based on the amount of energy and energy grade reduction.Besides,a case study was conducted based on a residential community with a combined heat and power(CHP)-based district heating system(DHS)in Tianjin,China.Moreover,the effect of IT on heat demand,heat medium temperature,exhaust heat,extracted heat,coal consumption,carbon dioxide(CO_(2))emissions and sulfur dioxide(SO_(2))emissions as well as the effect of three types of insulation materials(i.e.,expanded polystyrene,rock wool and glass wool)on the OEIT and minimum annual total environmental impact were studied.The results reveal that the optimization model can be used to determine the OEIT.When the OEIT of expanded polystyrene,rock wool and glass wool is used,the annual total environmental impact can be reduced by 84.563%,83.211%,and 86.104%,respectively.It can be found that glass wool is more beneficial to the environment compared with expanded polystyrene and rock wool.展开更多
Background:Currently,direct conversion from somatic cells to neurons requires virus-mediated delivery of at least one transcriptional factor or a combination of several small-molecule compounds.Delivery of transcripti...Background:Currently,direct conversion from somatic cells to neurons requires virus-mediated delivery of at least one transcriptional factor or a combination of several small-molecule compounds.Delivery of transcriptional factors may affect genome stability,while small-molecule compounds may require more evaluations when applied in vivo.Thus,a defined medium with only conventional growth factors or additives for cell culture is desirable for inducing neuronal trans-differentiation.Results:Here,we report that a defined medium(5C)consisting of basic fibroblast growth factor(bFGF),N2 supplement,leukemia inhibitory factor,vitamin C(Vc),andβ-mercaptoethanol(βMe)induces the direct conversion of somatic cells to cells with neuronal characteristics.Application of 5C medium converted mouse embryonic fibroblasts(MEFs)into TuJ+neuronal-like cells,which were capable of survival after being transplanted into the mouse brain.The same 5C medium could convert primary rat astrocytes into neuronal-like cells with mature electrophysiology characteristics in vitro and facilitated the recovery of brain injury,possibly by inducing similar conversions,when infused into the mouse brain in vivo.Crucially,5C medium could also induce neuronal characteristics in several human cell types.Conclusions:In summary,this 5C medium not only provides a means to derive cells with neuronal characteristics without viral transfection in vitro but might also be useful to produce neurons in vivo for neurodegenerative disease treatment.展开更多
The main difficulty in designing predictive controllers for permanent magnet motors with different topologies is the control of the additional current subspaces.The frequency of current components in these additional ...The main difficulty in designing predictive controllers for permanent magnet motors with different topologies is the control of the additional current subspaces.The frequency of current components in these additional subspaces(harmonic subspaces and zero-sequence loop/subspaces)is several times the fundamental current frequency.Moreover,the inner voltage source would vary with operation conditions,and there are also different views about the causes of inner voltage sources.This paper analyses the inner voltage sources in these additional current subspaces for permanent magnet motors with different drive topologies using simulation and experiment.Based on the results of the simulations and experiments,we analyze the sources and characteristics of the inner voltage sources and provide a predictive model calibration method for the components in these additional subspaces.Finally,the deadbeat current control scheme based on calibrated look-up table is designed and verified.展开更多
文摘Objective:To explore the expression of CD151 in gastric cancer tissues and its clinical significance.Methods:Immunohistochemistry was employed to detect the expression of CD151 in gastric cancer tissues and adjacent normal tissues.The relationship between CD151 expression and the clinicopathological characteristics of gastric cancer was analyzed.Results:The expression of CD151 in gastric cancer tissues was significantly higher than in adjacent normal tissues(P<0.05).It was associated with the degree of differentiation,depth of invasion,lymph node metastasis,and TNM staging of gastric cancer.The survival time of patients with high CD151 expression was significantly shorter than that of those with low expression(P<0.05).Conclusion:High expression of CD151 in gastric cancer tissues is correlated with the malignant biological behavior of gastric cancer and can serve as an indicator for evaluating the prognosis of gastric cancer.
基金supported by the Forestry Public Benefit Research Projects of National Forestry Administration under Grant No.201304303National Natural Science Foundation of China under Grant No.31370619+1 种基金Science and Technology Project of the Fujian Province under Grant No.2014N0002China Postdoctoral Science Foundation under Grant No.132300148
文摘Biomass production and nutrient (N, P, K, Ca and Mg) accumulation, distribution and cycling were quantified in young, mature and over-mature (10-, 22-, and 34-year old) Chinese fir [Cunninghamia lanceolate (Lamb.) Hook] plantations in southern China. Total stand biomass of young, mature and over-mature stands was 38, 104 and 138 t ha-1 respectively. Biomass production increased significantly with age. Stem wood represented the highest percentage of stand biomass, accounting for 41, 55 and 63 % in the young, mature and over-mature plan- tations respectively. Nutrients concentration was highest in live needles and branches, and lowest in stem wood. The plantations accumulated more N, followed by K, Ca, Mg, and P. Nutrient return amount, nutrient utilization effi- ciency, nutrient turnover time, the ratio of nutrient return and uptake increased with stand age, which implies that young Chinese fir deplete soil nutrients to maintain growth, and efficiently utilize nutrients to decrease dependence on soil nutrients as they age. Harvesting young Chinese fir plantations would therefore lead to high nutrient loss, but prolonging the rotation length could improve soil recovery, and help sustain productivity in the long-term. Improved nutrient return through litterfall as stands get older may also be beneficial to nutrient pool recovery.
基金This work was financially supported by National Science and Technology Major Project of the Ministry of Science and Technology of China(2016ZX05065-001),Key Research Project of Shandong Province(2019GHY112029 and 2019GSF109090)and Higher Education Research and Development Project of Shandong Province(J17KA033).
文摘Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well.A mathematical model is developed to simulate flowing pressures and pressure drops of CBM column from well head to bottom hole.The measured parameters and independent variables of flow rates,flowing pressures and temperatures are involved in CBM producing process along the annulus.The developed relationships are validated against full-scale measured data in single-phase CBM wellbores.The proposed methodology can analyze the dynamic behavior in CBM reservoir and process of CBM flow with an overall accuracy of 2%.The calculating process of flowing pressures involves friction factor with variable Reynolds number and CBM temperature and compressibility factor with gravitational gradients.The results showed that the effect of flowing pressure on CBM column was more obvious than that on CBM and water column accompanied by an increase of dynamic water level.The ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water column.Bottom-hole pressure declined with the decreased flowing pressure of CBM column along the annulus.It will lead to the results of the increased pressure drop of CBM column and CBM flow rate in single-phase CBM wellbores.
基金supported by the National Magnetic Confinement Fusion Energy Research and Development Program of China(Nos.2019YFE03090100,2019YFE03040004)the National Science Foundation for Young Scientists of China(No.12005052)。
文摘Data analysis on tokamak plasmas is mainly based on various diagnostic systems,which are usually modularized and independent of each other.This leads to a large amount of data not being fully and effectively exploited so that it is not conducive to revealing the deep physical mechanism.In this work,Bayesian probability inference with machine learning methods have been applied to the electron cyclotron emission and Thomson scattering diagnostic systems on HL-2A/2M,and the effects of integrated data analysis(IDA)on the electron temperature of HL-2A with Bayesian probability inference are demonstrated.A program is developed to infer the whole electron temperature profile with a confidence interval,and the program can be applied in online analysis.The IDA results show that the full profile of the electron temperature can be obtained and the diagnostic information is more comprehensive and abundant with IDA.The inference models for electron temperature analysis are established and the developed programs will serve as an experimental data analysis tool for HL-2A/2M in the near future.
基金supported by the National Natural Science Foundation of China (No.32171882)the Science and Technology Innovation Program of Hunan Province of China (2021RC4062)Scientific Research Project of Hunan Provincial Department of Education (20K143).
文摘The residual resources of ramie fiber-based textile products were used as raw materials.Ramie fiber felt(RF)was modified by NaClO_(2) aqueous solution and then impregnated with water-based epoxy resin(WER).RF/WER transparent composite materials were prepared by lamination hot pressing process.The composite materials’color difference,transmittance,haze,density,water absorption,and mechanical properties were determined to assess the effects of NaClO_(2) treatment and the number of ramie fiber layers on the properties of the prepared composites.The results showed significantly improved optical and mechanical properties of the RF/WER transparent composites after NaClO_(2) treatment.With the increase of ramie fiber layers,the composites’whiteness,transmittance,and water absorption decreased while the haze increased.For material with three layers,the optical transmittance in the visible light region was 82%,and the haze was 96%,indicating the material has both high transmittance and high haze characteristics.The tensile strength increases with the increase of the number of layers,and the tensile strength of the composite with six layers is 243 MPa.This study broadens the scope of application of ramie fiber as a new option for home decoration materials.
文摘CURRENTLY,new technologies and applications are presenting both new challenges and new opportunities to the field of electric machines and motors.The continual dedicated effort of researchers is required to achieve the high-performance and high-reliability of electric machines while ensuring their cost-effectiveness.In motor design,with the advancements of optimization theory and technology,increasingly effective methods have been developed for the design of motors.
基金Special Foundation of National Science and Technology Basic Research(2013FY112300).
文摘Aims Aquatic plants play an important role in freshwater ecosystems.Previous works have largely focused on the functional significance of plant above ground parts,with much less attention on the root structures of aquatic plants.In this study,we divided 21 aquatic plants(including five introduced plants)into multiple plant groups(different life forms,monocot/eudicot and introduced/native)with the goal of addressing two questions:(i)what root structures do aquatic plants exhibit,and(ii)are there differences among these plant groups?Methods Twenty-one aquatic plants belonging to four life forms(free-float-ing,emergent,floating-leaved and submerged)were collected at the near flowering stage from a typical macrophyte-dominated lake in the yangtze River Basin,China.The following root topological parameters were quantified:altitude(a),path length(pe),magnitude(M),mean topological length(b),topological index(TI)and normed indices qa and qb.Important Findings The root topological indices TI,qa and qb for the 21 aquatic plants were 0.724±0.013,0.290±0.031 and 0.152±0.024(means±S.E.),respectively,revealing a general pattern of dichotomous branching,except for the aquatic root of Myriophyllum aquati-cum(Vell.)Verdc.,which displays herringbone branching.All three topological indices were significantly lower for monocots(TI=0.700±0.130,qa=0.191±0.149 and qb=0.086±0.236)than eudicots(TI=0.752±0.206,qa=0.405±0.569 and qb=0.229±0.393),indicating that the roots of monocots are typi-cally more dichotomous-like than those of eudicots.Among the four life forms,the three topological indices for emergent plants(TI=0.832±0.006,qa=0.616±0.018 and qb=0.381±0.014)were significantly higher than those of the other three life forms.Overall,there was no difference between the topological indices of introduced and native aquatic plants,but the introduced species M.aquaticum and Alternanthera philoxeroides(Mart.)Griseb.had both aquatic and edaphic roots as well as unusual functions,which may help explain their strong viability.
基金Supported by the general program of National Natural Science Foundation of China under Grant 51677159a grant(Project No.CityU 21201216)from the Research Grants Council of HKSAR,China.
文摘Control strategies play a key role for operation of electric machines,which would directly affect the whole system performance.In fact,different control strategies have been executed and explored for electric machines,which bring great impacts to industrial development and human society.This paper investigates and discusses the advantages control strategies for electric machines,including the field oriented control(FOC),direct torque control(DTC),finite control set model predictive control(FCS-MPC),sensorless control,and fault tolerant control(FTC).The corresponding control principles,control targets,fundamental approaches,advanced approaches,methodologies,merits and shortcomings are revealed and analyzed in detail.
文摘The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 : 1 complexation of Zn^2+ and Cd^2+ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer (ILCT) between the d^10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.
基金supported by the Ministry of Science and Technology(No.2017YFA0205000)National Natural Science Foundation of China(Nos.21303024,21365003,21463003,51478123,21962003,21902033)+6 种基金the National Key Basic Research Program of China(No.2012CB933001)the Chinese Academy of Sciences(No.YZ201318)The jiangxi Provincial"Ganpo Talents 555 Projects",Jiangxi Provincial Education Department Fund(No.KJLD13080)Jiangxi Provincial Funds for Distinguished Young Scientists(No.20153BCB23001)Jjiangxi Provincial Project of Scientific and Technological Innovation Team(No.20152BCB24008)Jiangxi Province Youth Science Foundation Project(No.20192BAB216013)Science and Technology Project of Jiangxi Province Education Department(No.180775)are also gratefully acknowledged.
文摘Amino acids are basic units to construct a protein with the assistance of various interactions.During this building process,steric hindrance derived from amino acid side groups or side chains is a factor that could not be ignored.In this contribution,adsorption behaviors of C-terminal amino acid derivatives with amino acid residues fused in 3,4,9,10-perylenetetracarboxylic dianhydride were investigated by scanning tunneling microscopy(STM)and density functional theory(DFT)calculations at various liquid/solid interfaces.STM results at 1-phenyloctane/HOPG interface show that N,N'-3,4,9,10-perylenedicarboximide(GP)and N,N'-methyl-3,4,9,10-perylenedicarboximide(AP)formed linear and herringbone structures,respectively.The driving force could be attributed to different H-bonding sites induced by steric hindrance at side groups.N,N'-Benzyl-3,4,9,10-perylenedicarboximide(PP)generates both linear and herringbone structures because steric hindrance changes the H-bonding sites between PP molecules,whereas N,N'-isopropyl-3,4,9,10-perylenedicarboximide(LP)failed to be imaged because of strong steric hindrance coming from larger side group.To further investigate the impact of steric hindrance,we utilized octanoic acid(OA)as solvent to capture the adsorption details of LP and PP.We found that OA molecules drag PP and LP molecules in a different direction to generate linear structure,impeding the molecular rotation.The structure–solvent relationship shows that the steric hindrance is brought by the large side group,which makes it easier to recognize OA molecules at the interface.These results demonstrate that steric effect plays a significant role in altering interaction sites of the compounds during the adsorption process at the liquid/solid interface.
基金supported by the National Key Research and Development Program of China(2017YFA0104800)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(XDA16010505)+5 种基金the National Natural Science Foundation of China(81570944,31300901,and 31900547)Fountain-Valley Life Sciences Fund of University of Chinese Academy of Sciences Education FoundationScience and Technology Planning Project of Guangdong Province,China(2017B030314056)Natural Science Foundation of Guangdong Province,China(2017A030310098,2016A030313165,2015A030310026,and 2014A030313732)Science and Technology Planning Project of Guangzhou,China(201904010474)Shenzhen Peacock Plan(KQTD2016113015442590)。
文摘A stable,rapid and effective neural differentiation method is essential for the clinical applications of human embryonic stem cells(ESCs)or induced pluripotent stem cells(iPSCs)in treating neurological disorders and diseases.Herein,we established a novel and robust monolayer differentiation method to produce functional neural progenitor cells(NPCs)from human ESC/iPSCs on Type I Collagen.The derived cells not only displayed the requisite markers,but also behaved similarly to classic NPCs both in vitro and in vivo.Upon transplantation into traumatic brain injury model,the derived NPCs facilitated recovery from injury.We also found that SMAD signaling stayed down throughout the differentiation process on Type I Collagen,and the pluripotent signals were rapidly downregulated along with raising up of neural early markers on the third day.Meanwhile,ATAC-seq data showed the related mediation of distinct transcriptome and global chromatin dynamics during NPC induction.Totally,our results thus provide a convenient way to generate NPCs from human ESC/iPSCs for neural diseases’treatment.
基金The present work was financially supported by the National Natural Science Foundation of China(31800299,31170339)the general financial grant from the China Postdoctoral Science Foundation(2017M622184)the Special Foundation of National Science and Technology Basic Research(2013FY112300).
文摘Aims Environmental heterogeneity affects the performance of clonal aquatic plants.Few researchers integrated two aspects of heterogeneity into the study of clonal plant ecology.The aims of the present study are to(i)test whether different substrate heterogeneity and submergence exert similar effects on plant performance and(ii)explore the foraging behaviour.Methods In this study,Scirpus yagara was subjected to multiple levels of substrate heterogeneity and submergence.Substrate treatments included one homogeneous substrate and three heterogeneous substrates(two-patch,four-patch and eight-patch).Water level treatments included 0,10 and 30 cm.Traits including ramet number,generation number,leaf number,bulb number,ramet height,culm length,rhizome length,clonal radius,spacer length,spacer thickness,total biomass,biomass of bulbs and biomass per bulb were measured.Important Findings Deeper water levels significantly reduced variables associated with growth such as ramet number,generation number,leaf number and bulb number,while substrate patchiness induced significant variations in traits such as spacer length and spacer thickness.Significant interactive effects of the two factors were found for ramet number,leaf number and spacer length.Scirpus yagara showed colonization towards the lake sediment patch in two-patch and four-patch substrates,and more structures were placed in the lake sediment patch.Especially for the two-patch substrate,all structures occupied the lake sediment patch.Two-sided intrusion was observed in the eight-patch substrate,which induced an even allocation of structures in different patches.The foraging behaviour was correlated with the patch size.
基金the Special Foundation of National Science and Technology Basic Research(2013FY112300)the National Natural Science Foundation of China(31900281).
文摘Clonal integration benefits clonal plants by buffering environmental stress and increasing resource extraction efficiency.However,the number of connected ramet generations that benefit from clonal integration in a clonal system has received relatively little attention.A pot experiment was conducted to evaluate the extent of physiological integration within the clonal system of Vallisneria natans consisting of a mother ramet and three sequentially connected offspring ramets.Mother ramets were grown in full sunlight,and offspring ramets were heavily shaded with limited light availability.Stolons between mother ramets and offspring ramets were severed or connected,but connection among the three offspring ramets remained.The photosynthetic ability of unshaded mother ramets of V.natans was significantly enhanced,but their biomass accumulation was greatly reduced when connected to shaded offspring ramets.Clonal integration significantly increased biomass accumulation,C and N availabilities,extracellular enzyme activities and microbial biomass of the first ramet generation(adjacent ramet),but not later ramet generations.Our results indicate that support from the mother ramet of V.natans may be limited to the adjacent offspring ramet in a clonal system under severe light stress,implying an effect of ramet generation.Our results contribute to a better understanding of the hierarchy and segmentation of clonal plants.These findings suggest that the extent of clonal integration plays a vital role in ecological interactions of the ramet population.
基金supported by the Scientific Research Project of Beijing Municipal Education Commission,China(KM201810017004)National Key R&D Program Project of China(No.2018YFC0704800)the“Engineering and Technology R&D Center of Clean Air Conditioning in Colleges of Shandong(Shandong Huayu University of Technology).”。
文摘The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual total environmental impact was established based on the amount of energy and energy grade reduction.Besides,a case study was conducted based on a residential community with a combined heat and power(CHP)-based district heating system(DHS)in Tianjin,China.Moreover,the effect of IT on heat demand,heat medium temperature,exhaust heat,extracted heat,coal consumption,carbon dioxide(CO_(2))emissions and sulfur dioxide(SO_(2))emissions as well as the effect of three types of insulation materials(i.e.,expanded polystyrene,rock wool and glass wool)on the OEIT and minimum annual total environmental impact were studied.The results reveal that the optimization model can be used to determine the OEIT.When the OEIT of expanded polystyrene,rock wool and glass wool is used,the annual total environmental impact can be reduced by 84.563%,83.211%,and 86.104%,respectively.It can be found that glass wool is more beneficial to the environment compared with expanded polystyrene and rock wool.
基金This work was supported by“Strategic Priority Research Program of the Chinese Academy of Sciences(XDA01020302)”the“National Natural Science Foundation of China(31422032,31421004)”+4 种基金the“Guangdong Natural Science Foundation(2014A030308002)”the“Guangdong Science and Technology Planning Project(2013B010404040),”the“Guangzhou Health Care Collaborative Innovation Program(201508020250)”We sincerely thank Dr.Chen Ling(mouse macrophages)Dr.Wang Lihui(HFFs)in GIBH,and Dr.Peng Xiang(BM-hMSCs)in Sun Yat-Sen University for providing cells。
文摘Background:Currently,direct conversion from somatic cells to neurons requires virus-mediated delivery of at least one transcriptional factor or a combination of several small-molecule compounds.Delivery of transcriptional factors may affect genome stability,while small-molecule compounds may require more evaluations when applied in vivo.Thus,a defined medium with only conventional growth factors or additives for cell culture is desirable for inducing neuronal trans-differentiation.Results:Here,we report that a defined medium(5C)consisting of basic fibroblast growth factor(bFGF),N2 supplement,leukemia inhibitory factor,vitamin C(Vc),andβ-mercaptoethanol(βMe)induces the direct conversion of somatic cells to cells with neuronal characteristics.Application of 5C medium converted mouse embryonic fibroblasts(MEFs)into TuJ+neuronal-like cells,which were capable of survival after being transplanted into the mouse brain.The same 5C medium could convert primary rat astrocytes into neuronal-like cells with mature electrophysiology characteristics in vitro and facilitated the recovery of brain injury,possibly by inducing similar conversions,when infused into the mouse brain in vivo.Crucially,5C medium could also induce neuronal characteristics in several human cell types.Conclusions:In summary,this 5C medium not only provides a means to derive cells with neuronal characteristics without viral transfection in vitro but might also be useful to produce neurons in vivo for neurodegenerative disease treatment.
基金a grant(Project No.SGDX2019081623101559)of Shenzhen–Hong Kong Innovation Circle Category C Project from the Science Technology and Innovation Committee of Shenzhen Municipality,Chinaa grant(Project No.ITP/027/19AP)from the Innovation and Technology Commission,Hong Kong SAR,China+1 种基金in part by the grants(Project No.TDG6000784,ARG9667251 and SRG7005583)from the Teaching Development Grant,Applied Research Grant and Strategy Research Grant,City University of Hong Kong,Hong Kong SAR,Chinaand in part by Collaborative Research Fund(Project No.C1052-21GF)from Research Grants Council,Hong Kong SAR,China.
文摘The main difficulty in designing predictive controllers for permanent magnet motors with different topologies is the control of the additional current subspaces.The frequency of current components in these additional subspaces(harmonic subspaces and zero-sequence loop/subspaces)is several times the fundamental current frequency.Moreover,the inner voltage source would vary with operation conditions,and there are also different views about the causes of inner voltage sources.This paper analyses the inner voltage sources in these additional current subspaces for permanent magnet motors with different drive topologies using simulation and experiment.Based on the results of the simulations and experiments,we analyze the sources and characteristics of the inner voltage sources and provide a predictive model calibration method for the components in these additional subspaces.Finally,the deadbeat current control scheme based on calibrated look-up table is designed and verified.