Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa bas...Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa based on the formation of Microcystis colony at high iron concentrations.The turbulent dissipation rate was calculated using a computational fluid dynamics(CFD)model to evaluate the intensity of turbulence.The effects of turbulence on the formation of Microcystis colony and the release of microcystin were analyzed.Results show that turbulence produced by aeration promoted the growth of Microcystis compared to that in stagnant water.Low intensity turbulence(4×10^(-8)-1×10^(-7) m2/s3)promoted the formation of Microcystis colonies,but high intensity turbulence(1.28×10^(-6)-1.8×10^(-5) m^(2)/s^(3))did not.The increase in the number of cells per colony was slower than that in total biomass,indicating that the low intensity turbulence induced colony formation via cell division,while the high level turbulence disaggregated colonies formed by both cell division and cell adhesion.Low aeration intensity induced more production of reactive oxygen species(ROS)and malondialdehyde(MDA)in the cells of Microcystis than those in high aeration intensity.In addition,the content of microcystin(MC)-LR in the cells was positively correlated with turbulence intensity,showing that turbulence affected not only the growth and aggregation of Microcystis colonies but also their toxin production.These findings provide a better understanding of the cyanobacterial bloom formation mechanisms and help to propose feasible methods to prevent the formation of Microcystis colonies in a natural environment.展开更多
‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristic...‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.展开更多
In this paper, Ni/Zr–Yb–O catalysts with different sodium contents are prepared by a co-precipitation method, using aqueous Na2CO3 solution as a precipitant, and the effect of sodium on the catalyst structure and ca...In this paper, Ni/Zr–Yb–O catalysts with different sodium contents are prepared by a co-precipitation method, using aqueous Na2CO3 solution as a precipitant, and the effect of sodium on the catalyst structure and catalytic performance for syngas methanation is extensively investigated using five Ni/Zr–Yb–O catalysts, containing 0, 0.5, 1.5,4.5 and 13.5 wt% Na^+, those are denoted as Cat-1, Cat-2, Cat-3, Cat-4 and Cat-5 respectively. It is found that the interaction between Ni and support determines the catalytic performance of Ni/Zr–Yb–O and the residual sodium content negatively affects the interaction between Ni and support. Cat-1 exhibits an excellent catalytic performance.During a long run time of 380 h, no deactivation is observed and both CO conversion and CH4 selectivity maintain a level above 90%. However, Cat-3 and Cat-5 suffer rapid deactivation under the same reaction condition. The characterization results indicate the strong interaction between Ni and support enables Cat-1 to possess well dispersed Ni species, resistance to sintering and carbon deposition and thus the excellent catalytic performance. However, the presence of sodium ions over Ni/Zr–Yb–O degrades the interaction between Ni and support and the catalytic performance, especially for the stability. The relative weak interaction between Ni and support results in severe sintering of both ZrO2 and Ni under the reaction condition, carbon deposition and the poor catalytic performance.展开更多
Objective: To explore the expression of c-Met mRNA in nasopharyngeal carcinomas (NPC) and its relation with clinical biological behavior. Methods: In situ hybridisation was used to detect mRNA expression of c-Met in 1...Objective: To explore the expression of c-Met mRNA in nasopharyngeal carcinomas (NPC) and its relation with clinical biological behavior. Methods: In situ hybridisation was used to detect mRNA expression of c-Met in 15 cases of non-tumor nasopharyngeal (NP), 55 cases of NPC. Results: The positive rates of c-Met mRNA in NP and NPC cells were 13.3% (2/15) and 61.8% (34/55) respectively. The expression of c-Met mRNA was significantly correlated with lymph node metastasis, local invasion (skull base erosion), and clinical stage. In cases with cervical lymph node metastasis, local invasion, and clinical stage III and IV (UICC), the positive rates of expression of c-Met mRNA were significantly higher than that in those without the conditions mentioned above (P < 0.05 or P < 0.01). But it was not significantly correlated with age, gender, histo- logic grade, and cranial nerve palsy (P > 0.05). Conclusion: The abnormal expression of c-Met gene was well correlated with the biological behavior of metastasis and invasion. To detection the expression of c-Met mRNA could serve as an important index to estimate the prognosis of NPC. C-Met may be a new diagnostic/therapeutic target of NPC.展开更多
Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found th...Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found that the preparation method exerted a significant effect on the activity of the Pd/TiO2 catalyst,and that the catalyst prepared by the polyethylene glycol reduction method exhibited the highest activity in the reduction of NOx.Characterization of the catalyst showed that,in the Pd/TiO2 catalyst prepared by the polyethylene glycol reduction method,the existing Pd species was Pd0,which is the desirable species for the H2-SCR of NOx.In situ DRIFTS studies demonstrated that over this catalyst,more chelating nitrite and monodentate nitrite species formed,both of which are reactive intermediates in the H2-SCR of NOx.All of these factors account for the high activity of Pd/TiO2 prepared by the polyethylene glycol reduction method.展开更多
Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the di...Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.展开更多
Electronic engineering of gallium nitride(Ga N) is critical for enhancement of its electrode performance.In this work, copper(Cu) cation substituted Ga N(Cu-Ga N) nanowires were fabricated to understand the electronic...Electronic engineering of gallium nitride(Ga N) is critical for enhancement of its electrode performance.In this work, copper(Cu) cation substituted Ga N(Cu-Ga N) nanowires were fabricated to understand the electronically engineered electrochemical performance for Li ion storage. Cu cation substitution was revealed at atomic level by combination of X-ray photoelectron spectroscopy(XPS), X-ray absorption fine structure(XAFS), density functional theory(DFT) simulation, and so forth. The Cu-Ga N electrode delivered high capacity of 813.2 m A h g^(-1) at 0.1 A g^(-1) after 200 cycles, increased by 66% relative to the unsubstituted Ga N electrode. After 2000 cycles at 10 A g^(-1),the reversible capacity was still maintained at326.7 m A h g^(-1). The DFT calculations revealed that Cu substitution introduced the impurity electronic states and efficient interatomic electron migration, which can enhance the charge transfer efficiency and reduce the Li ion adsorption energy on the Cu-Ga N electrode. The ex-situ SEM, TEM, HRTEM, and SAED analyses demonstrated the reversible intercalation Li ion storage mechanism and good structural stability. The concept of atomic-arrangement-assisted electronic engineering strategy is anticipated to open up opportunities for advanced energy storage applications.展开更多
As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivit...As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.展开更多
Because the breast cancer is an important factor that threatens women's lives and health,early diagnosis is helpful for disease screening and a good prognosis.Exosomes are nanovesicles,secreted from cells and othe...Because the breast cancer is an important factor that threatens women's lives and health,early diagnosis is helpful for disease screening and a good prognosis.Exosomes are nanovesicles,secreted from cells and other body fluids,which can reflect the genetic and phenotypic status of parental cells.Compared with other methods for early diagnosis of cancer(such as circulating tumor cells(CTCs)and circulating tumor DNA),exosomes have a richer number and stronger biological stability,and have great potential in early diagnosis.Thus,it has been proposed as promising biomarkers for diagnosis of early-stage cancer.However,distinguishing different exosomes remain is a major biomedical challenge.In this paper,we used predictive Convolutional Neural model to detect and analyze exosomes of normal and cancer cells with surface-enhanced Raman scattering(SERS).As a result,it can be seen from the SERS spectra that the exosomes of MCF-7,MDA-MB-231 and MCF-10A cells have similar peaks(939,1145 and 1380 cm^(-1)).Based on this dataset,the predictive model can achieve 95%accuracy.Compared with principal component analysis(PCA),the trained CNN can classify exosomes from different breast cancer cells with a superior performance.The results indicate that using the sensitivity of Raman detection and exosomes stable presence in the incubation period of cancer cells,SERS detection combined with CNN screening may be used for the early diagnosis of breast cancer in the future.展开更多
Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herei...Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herein,atomic Ni(Zn)sites that are uniquely coordinated with ternary Zn(Ni)/N/O ligands were successfully decorated on formamide-derived porous carbon nanomaterials,possibly forming an atomic structure of Ni(N_(2)O_(1))-Zn(N_(2)O_(1)),as studied by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy.With the mediation of additional O coordination,the Ni-Zn dual site induces significantly decreased desorption of molecular CO.The NiZn-NC decorated with rich Ni(N_(2)O_(1))-Zn(N_(2)O_(1))sites remarkably gained>97%CO Faraday efficiency over a wide potential range of -0.8 to -1.1 V(relative to reversible hydrogen electrode).Density functional theory computations suggest that the N/O dual coordination effectively modulates the electronic structure of the Ni-Zn duplex and optimizes the adsorption and conversion properties of CO_(2) and subsequent intermediates.Different from the conventional pathway of using Ni as the active site in the Ni-Zn duplex,it is found that the Ni-neighboring Zn sites in the Ni(N_(2)O_(1))-Zn(N_(2)O_(1))coordination showed much lower energy barriers of the CO_(2) protonation step and the subsequent dehydroxylation step.展开更多
Two-dimensional(2D)nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features.Herein,2D hafnium ditelluride(HfTe_(2)),a new member of transition metal tellurides,is e...Two-dimensional(2D)nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features.Herein,2D hafnium ditelluride(HfTe_(2)),a new member of transition metal tellurides,is exploited to support gold nanoparticles fabricating HfTe_(2)-Au nanocomposites.The nanohybrids can serve as novel 2D surface-enhanced Raman scattering(SERS)substrate for the label-free detection of analyte with high sensitivity and reproducibility.Chemical mechanism originated from HfTe_(2) nanosheets and the electromagnetic enhancement induced by the hot spots on the nano-hybrids may largely contribute to the superior SERS effect of HfTe_(2)-Au nanocomposites.Finally,HfTe_(2)-Au nanocomposites are utilized for the label-free SERS analysis of foodborne pathogenic bac-teria,which realize the rapid and ultrasensitive Raman test of Escherichia coli,Listeria mono-cytogenes,Staphylococcus aureus and Salmonella with the limit of detection of 10 CFU/mL and the maximum Raman enhancement factor up to 1.7×10^(8).Combined with principal component analysis,HfTe_(2)-Au-based SERS analysis also completes the bacterial classification without extra treatment.展开更多
Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode mater...Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode materials as active materials for lithium-/sodium-ion batteries generally suffer from large volume changes and poor rate performance.In response,we synthesized defect-rich N,S co-doped two dimensional(2D)nanosheet-assembled porous carbon microspheres(N,S-PCS)via simple hydrothermal,carbonization and etching process based on the principle of Schiff base reaction.The N,S-PCS structure is thus constructed by removing Fe7S8 nanoparticles from the carbon skeleton to form porous microspheres with N,S doping.Therefore,the micromorphology characteristic,pore structure and electroconductivity of carbon materials are effectively optimized via heteroatom doping and surface engineering.As expected,the prepared N,S-PCS electrodes exhibit excellent electrochemical performance in both lithium-ion and sodium-ion batteries.For lithium-ion batteries,it achieves reversible capacities of 1045 and 237 mAh g^(-1) at 0.1 and 20 A g^(-1),respectively.For sodium-ion batteries,it shows good cycling stability with a capacity of 157 mAh g^(-1) after 500 cycles at 1 A g^(-1).Experimental and theoretical calculation results confirm that the N,S co-doping strategies help to improve the structural stability,shorten the ion diffusion paths,and promote the reaction kinetics,thus achieving excellent electrochemical performance.This work is instructive for the practical application of nonmetal doping functionalized porous carbon structures for metal-ion batteries.展开更多
Theranostic carbon dots(CDs)have attracted widespread attention recently due to their tunable optical properties and diverse bioactivities.Beyond fluorescent imaging application,the photothermal property endows CDs wi...Theranostic carbon dots(CDs)have attracted widespread attention recently due to their tunable optical properties and diverse bioactivities.Beyond fluorescent imaging application,the photothermal property endows CDs with the potential for microbial inactivation.However,realization of the effective conversion between fluorescence and heat in one CD system has rarely been reported.Herein,we provide a simple strategy for targeted microbial theranostics based on 4-carboxyphenylboronic acid-derived CDs(PCBA-CDs)which possess concentration-dependent photoluminescence/photothermal features.At lower concentrations,PCBA-CDs show bright and stable fluorescent signals ranging from blue to green.The fluorescence intensity gradually decreases with increasing concentration,while on the contrary,the photothermal effect of PCBA-CDs ascends progressively due to the rearrangement of electronic transitions in aggregated CDs.PCBA-CDs also demonstrate high affinity to the polysaccharide structures on the surface of microbe which allows rapid microbial fluorescence imaging as well as specific photothermal ablation of pathogens in skin wounds using PCBA-CDs at lower and higher concentrations,respectively.This study supplies a facile nanotheranostic strategy for just-in-time microbial management using bioactive CDs.展开更多
Rapid detection of pathogens present on contaminated surfaces is crucial for food safety and public health due to the high morbidity and mortality of bacterial infections.Herein,a sensitive and efficient method for on...Rapid detection of pathogens present on contaminated surfaces is crucial for food safety and public health due to the high morbidity and mortality of bacterial infections.Herein,a sensitive and efficient method for on-site identification of foodborne pathogens on anisotropic surfaces was developed by using an in situ instantaneously prepared surface-enhanced Raman scattering(SERS)platform.To achieve this,molybdenum-doped gallic acidderived carbon dots(MCDs)are utilized as the reductant for synthesizing Au@MCDs nanohybrids within just 3 s at ambient temperature.The synergistic effect of the electromagnetic enhancement and charge transfer of Au@MCDs enables excellent SERS performance 10 times stronger than bare Au NPs.The bioassay platform requires less than 5 min to complete the quantitative detection of foodborne pathogens on various microbial-contaminated interfaces with a sensitivity of 10 CFU/m L.This innovative strategy breaks the long-standing limitations of SERS substrates in practical use,such as the time-consuming process,interference of residual surfactants,poor surface stability,and few application scenarios,providing a promising tool for widespread applications in biomedical research and clinical diagnostics.展开更多
In this perspective article,we first recall the historic background of human-cyber-physical systems(HCPSs),and then introduce and clarify important concepts.We discuss the key challenges in establishing the scientific...In this perspective article,we first recall the historic background of human-cyber-physical systems(HCPSs),and then introduce and clarify important concepts.We discuss the key challenges in establishing the scientific foundation from a system engineering point of view,including(1)complex heterogeneity,(2)lack of appropriate abstractions,(3)dynamic black-box integration of heterogeneous systems,(4)complex requirements for functionalities,performance,and quality of services,and(5)design,implementation,and maintenance of HCPS to meet requirements.Then we propose four research directions to tackle the challenges,including(1)abstractions and computational theory of HCPS,(2)theories and methods of HCPS architecture modelling,(3)specification and verification of model properties,and(4)software-defined HCPS.The article also serves as the editorial of this special section on cyber-physical systems and summarises the four articles included in this special section.展开更多
The existence of narrow and brittle white etching layers(WELs)on the rail surface is often linked with the formation of rail defects such as squats and studs,which play the key roles in rail surface degradation and tr...The existence of narrow and brittle white etching layers(WELs)on the rail surface is often linked with the formation of rail defects such as squats and studs,which play the key roles in rail surface degradation and tribological performance.In the present study,a systematic investigation on stress/strain distribution and fatigue life of the WEL during wheel-rail rolling contact was conducted based on a numerical model considering the realistic wheel geometry.This is the first study considering the influence of rail materials,loading pressure,frictional condition,WEL geometry(a/b),and slip ratio(Sr)in the practical service conditions at the same time.The results revealed much higher residual stress in WEL than in rail matrix.Stress changes along the rail depth matched with the previously reported microstructure evolutions.The current work revealed that the maximum difference in contact stress between the wheel passages of rail matrix and the WEL region(noted as stress variation)rises with the increase of loading pressure,the value of a/b,and Sr;but drops with the friction coefficient(μ).In addition,a critical length–depth ratio of 5 for a/b has been found.The fatigue parameter,FP,of the WEL decreased quickly with the length–depth ratio when it was less than 5 and then increased slightly when it was larger than 5.This study also revealed that the fatigue life of the WEL was reduced for high strength head hardened(HH)rail compared with standard carbon(SC)rail.展开更多
Red mud,as a solid waste produced during the alumina production,can cause severe ecoenvironmental pollution and health risks to human.Therefore,the resourcing of this type of solid waste is an effective way for the su...Red mud,as a solid waste produced during the alumina production,can cause severe ecoenvironmental pollution and health risks to human.Therefore,the resourcing of this type of solid waste is an effective way for the sustainable development.This paper reviews the recent progress on red mud-based catalysts for the removal of typical air pollutants,such as the catalytic reduction of nitrogen oxides(NO_(x))by NH_(3)(NH_(3)-SCR)and the catalytic oxidation of CO and volatile organic compounds(VOCs).The factors influencing the catalytic performance and the structure–activity relationship have been discussed.Future prospects and directions for the development of such catalysts are also proposed.This review would benefit for the high value-added utilizations of red mud in mitigating atmospheric pollutions.展开更多
基金Supported by the National Natural Science Foundation of China(No.51979236)。
文摘Aeration induced turbulence was considered as an important measure to control the occurrence of cyanobacterial blooms in many lakes.Different aeration intensities were set for the culture of Microcystis aeruginosa based on the formation of Microcystis colony at high iron concentrations.The turbulent dissipation rate was calculated using a computational fluid dynamics(CFD)model to evaluate the intensity of turbulence.The effects of turbulence on the formation of Microcystis colony and the release of microcystin were analyzed.Results show that turbulence produced by aeration promoted the growth of Microcystis compared to that in stagnant water.Low intensity turbulence(4×10^(-8)-1×10^(-7) m2/s3)promoted the formation of Microcystis colonies,but high intensity turbulence(1.28×10^(-6)-1.8×10^(-5) m^(2)/s^(3))did not.The increase in the number of cells per colony was slower than that in total biomass,indicating that the low intensity turbulence induced colony formation via cell division,while the high level turbulence disaggregated colonies formed by both cell division and cell adhesion.Low aeration intensity induced more production of reactive oxygen species(ROS)and malondialdehyde(MDA)in the cells of Microcystis than those in high aeration intensity.In addition,the content of microcystin(MC)-LR in the cells was positively correlated with turbulence intensity,showing that turbulence affected not only the growth and aggregation of Microcystis colonies but also their toxin production.These findings provide a better understanding of the cyanobacterial bloom formation mechanisms and help to propose feasible methods to prevent the formation of Microcystis colonies in a natural environment.
基金supported by the national 948 subject ‘Introduction of fresh-eating jujube cultivar and new cultivating technology from Israel(2012-4-61)’
文摘‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.
基金Supported by the National Natural Science Foundation of China(21673187,21336009,21576228)National Key Technology Support Program of China(2014BAC10B01).
文摘In this paper, Ni/Zr–Yb–O catalysts with different sodium contents are prepared by a co-precipitation method, using aqueous Na2CO3 solution as a precipitant, and the effect of sodium on the catalyst structure and catalytic performance for syngas methanation is extensively investigated using five Ni/Zr–Yb–O catalysts, containing 0, 0.5, 1.5,4.5 and 13.5 wt% Na^+, those are denoted as Cat-1, Cat-2, Cat-3, Cat-4 and Cat-5 respectively. It is found that the interaction between Ni and support determines the catalytic performance of Ni/Zr–Yb–O and the residual sodium content negatively affects the interaction between Ni and support. Cat-1 exhibits an excellent catalytic performance.During a long run time of 380 h, no deactivation is observed and both CO conversion and CH4 selectivity maintain a level above 90%. However, Cat-3 and Cat-5 suffer rapid deactivation under the same reaction condition. The characterization results indicate the strong interaction between Ni and support enables Cat-1 to possess well dispersed Ni species, resistance to sintering and carbon deposition and thus the excellent catalytic performance. However, the presence of sodium ions over Ni/Zr–Yb–O degrades the interaction between Ni and support and the catalytic performance, especially for the stability. The relative weak interaction between Ni and support results in severe sintering of both ZrO2 and Ni under the reaction condition, carbon deposition and the poor catalytic performance.
文摘Objective: To explore the expression of c-Met mRNA in nasopharyngeal carcinomas (NPC) and its relation with clinical biological behavior. Methods: In situ hybridisation was used to detect mRNA expression of c-Met in 15 cases of non-tumor nasopharyngeal (NP), 55 cases of NPC. Results: The positive rates of c-Met mRNA in NP and NPC cells were 13.3% (2/15) and 61.8% (34/55) respectively. The expression of c-Met mRNA was significantly correlated with lymph node metastasis, local invasion (skull base erosion), and clinical stage. In cases with cervical lymph node metastasis, local invasion, and clinical stage III and IV (UICC), the positive rates of expression of c-Met mRNA were significantly higher than that in those without the conditions mentioned above (P < 0.05 or P < 0.01). But it was not significantly correlated with age, gender, histo- logic grade, and cranial nerve palsy (P > 0.05). Conclusion: The abnormal expression of c-Met gene was well correlated with the biological behavior of metastasis and invasion. To detection the expression of c-Met mRNA could serve as an important index to estimate the prognosis of NPC. C-Met may be a new diagnostic/therapeutic target of NPC.
基金supported by the National Key R&D Program of China(2017YFC0210700)the National Natural Science Foundation of China(21876009,21611130170)+1 种基金the Beijing Municipal Natural Science Foundation(8162030)the Fundamental Research Funds for the Central Universities(XK1802-1)~~
文摘Pd/TiO2 catalysts prepared by three different methods(impregnation,deposition-precipitation,and polyethylene glycol reduction)were investigated in the selective catalytic reduction of NOx by H2(H2-SCR).It was found that the preparation method exerted a significant effect on the activity of the Pd/TiO2 catalyst,and that the catalyst prepared by the polyethylene glycol reduction method exhibited the highest activity in the reduction of NOx.Characterization of the catalyst showed that,in the Pd/TiO2 catalyst prepared by the polyethylene glycol reduction method,the existing Pd species was Pd0,which is the desirable species for the H2-SCR of NOx.In situ DRIFTS studies demonstrated that over this catalyst,more chelating nitrite and monodentate nitrite species formed,both of which are reactive intermediates in the H2-SCR of NOx.All of these factors account for the high activity of Pd/TiO2 prepared by the polyethylene glycol reduction method.
文摘Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.
基金supported by the National Natural Science Foundation of China(51672144,51572137,5170218121905152,52072196,52002199,52002200)the Major Basic Research Program of Natural Science Foundation of Shandong Province(ZR2020ZD09)+5 种基金the Shandong Provincial Key Research and Development Program(SPKR&DP)(2019GGX102055)the Natural Science Foundation of Shandong Province(ZR2019BEM042 ZR2020QE063,ZR2020MB045)the Innovation and Technology Program of Shandong Province(2020KJA004)the Innovation Pilot Project of Integration of Science,Education and Industry of Shandong Province(2020KJC-CG04)the Guangdong Basic and Applied Basic Research Foundation(019A15151109332020A1515111086,2020A1515110219)the Shandong Provincial Universities Young Innovative Talent Incubation ProgramInorganic Non-metallic Materials Research and Innovation Team,and Taishan Scholars Program of Shandong Province(ts201511034)。
文摘Electronic engineering of gallium nitride(Ga N) is critical for enhancement of its electrode performance.In this work, copper(Cu) cation substituted Ga N(Cu-Ga N) nanowires were fabricated to understand the electronically engineered electrochemical performance for Li ion storage. Cu cation substitution was revealed at atomic level by combination of X-ray photoelectron spectroscopy(XPS), X-ray absorption fine structure(XAFS), density functional theory(DFT) simulation, and so forth. The Cu-Ga N electrode delivered high capacity of 813.2 m A h g^(-1) at 0.1 A g^(-1) after 200 cycles, increased by 66% relative to the unsubstituted Ga N electrode. After 2000 cycles at 10 A g^(-1),the reversible capacity was still maintained at326.7 m A h g^(-1). The DFT calculations revealed that Cu substitution introduced the impurity electronic states and efficient interatomic electron migration, which can enhance the charge transfer efficiency and reduce the Li ion adsorption energy on the Cu-Ga N electrode. The ex-situ SEM, TEM, HRTEM, and SAED analyses demonstrated the reversible intercalation Li ion storage mechanism and good structural stability. The concept of atomic-arrangement-assisted electronic engineering strategy is anticipated to open up opportunities for advanced energy storage applications.
基金funded by the National Natural Science Foundation of China(Grant Nos.22005167 and 21905152)the Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2020QB125 and ZR2020MB045)+1 种基金the China Postdoctoral Science Foundation(Grant Nos.2021M693256,2021T140687 and 2022M713249)the Qingdao Postdoctoral Applied Research Project and the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province。
文摘As an emerging member of the two-dimensional(2D)material family,V_(2)CT_(X)MXene shows great potential in the application of lithium-ion capacitors(LICs)due to its unique structure and excellent electrical conductivity.However,severe nanosheets stacking and intra-layer transport barriers have limited the further development of V_(2)CT_(X)MXene-based materials.Herein,we prepared Kions and–O functional group co-modified V_(2)CT_(X)MXene(VCT-K)and further incorporated it with single-walled carbon nanotube(SWCNT),obtaining freestanding V_(2)CT_(X)composite films(VCT-K@C)with the 3D conductive network.Significantly,K+ions were introduced into V_(2)CT_(X)MXene to stabilize the interlayer structure and prevent the aggregation of nanosheets,the terminal group of–O was controllably modified on the surface of MXene to improve the Li+ions storage reversible capacities and the SWCNT acted as the bridge between MXene nanosheets to opens up the channels for ion/electron transportation in the longitudinal direction.Benefited from the synergistic effect of VCT-K and SWCNT,the VCT-K@C exhibits superior reversible specific capacities of 671.8 mA h g^(-1)at 0.1 A g^(-1)and 318 mA h g^(-1)at 1.0 A g^(-1).Furthermore,the assembled LICs with VCT-K@C anode coupling activated carbon(AC)cathode deliver an outstanding power density of 19.0 kW kg^(-1)at 67.4 Wh kg^(-1),a high energy density of 140.5 Wh kg^(-1)at 94.8 W kg^(-1)and a stable capacitance retention of 86%after 6000 cycles at 10 A g^(-1).Such unique structures and excellent electrochemical properties are expected to pave the way for the large-scale application in LICs of MXene-based materials.
基金This work was supported by the National Natural Science Foundation of China(62175071,11964032,31300691,32071399 and 61675072)the Science and Technology Project of Guangdong Province of China(2017A020215059)+2 种基金the Science and Technology Project of Guangzhou City(201904010323 and 2019050001)the Innovation Project of Graduate School of South China Normal University(2019LKXM023)Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education(Fujian Normal University)(JYG2008).
文摘Because the breast cancer is an important factor that threatens women's lives and health,early diagnosis is helpful for disease screening and a good prognosis.Exosomes are nanovesicles,secreted from cells and other body fluids,which can reflect the genetic and phenotypic status of parental cells.Compared with other methods for early diagnosis of cancer(such as circulating tumor cells(CTCs)and circulating tumor DNA),exosomes have a richer number and stronger biological stability,and have great potential in early diagnosis.Thus,it has been proposed as promising biomarkers for diagnosis of early-stage cancer.However,distinguishing different exosomes remain is a major biomedical challenge.In this paper,we used predictive Convolutional Neural model to detect and analyze exosomes of normal and cancer cells with surface-enhanced Raman scattering(SERS).As a result,it can be seen from the SERS spectra that the exosomes of MCF-7,MDA-MB-231 and MCF-10A cells have similar peaks(939,1145 and 1380 cm^(-1)).Based on this dataset,the predictive model can achieve 95%accuracy.Compared with principal component analysis(PCA),the trained CNN can classify exosomes from different breast cancer cells with a superior performance.The results indicate that using the sensitivity of Raman detection and exosomes stable presence in the incubation period of cancer cells,SERS detection combined with CNN screening may be used for the early diagnosis of breast cancer in the future.
基金National Natural Science Foundation of China,Grant/Award Number:22071137Key Projects of China National Key R&D Plan,Grant/Award Number:2018YFE0118200+1 种基金Key Projects of Shandong Key R&D plan,Grant/Award Number:2019JZZY010506Taishan Scholar Foundation,Grant/Award Number:tspd20210308。
文摘Design of supportive atomic sites with a controllably adjusted coordinating environment is essential to advancing the reduction of CO_(2) to value-added fuels and chemicals and to achieving carbon neutralization.Herein,atomic Ni(Zn)sites that are uniquely coordinated with ternary Zn(Ni)/N/O ligands were successfully decorated on formamide-derived porous carbon nanomaterials,possibly forming an atomic structure of Ni(N_(2)O_(1))-Zn(N_(2)O_(1)),as studied by combining X-ray photoelectron spectroscopy and X-ray absorption spectroscopy.With the mediation of additional O coordination,the Ni-Zn dual site induces significantly decreased desorption of molecular CO.The NiZn-NC decorated with rich Ni(N_(2)O_(1))-Zn(N_(2)O_(1))sites remarkably gained>97%CO Faraday efficiency over a wide potential range of -0.8 to -1.1 V(relative to reversible hydrogen electrode).Density functional theory computations suggest that the N/O dual coordination effectively modulates the electronic structure of the Ni-Zn duplex and optimizes the adsorption and conversion properties of CO_(2) and subsequent intermediates.Different from the conventional pathway of using Ni as the active site in the Ni-Zn duplex,it is found that the Ni-neighboring Zn sites in the Ni(N_(2)O_(1))-Zn(N_(2)O_(1))coordination showed much lower energy barriers of the CO_(2) protonation step and the subsequent dehydroxylation step.
基金supported by the National Natural Science Foundation of China(11874021,61675072 and 21505047)the Science and Technology Project of Guangdong Province of China(2017A020215059)+2 种基金the Science and Technology Project of Guangzhou City(201904010323 and 2019050001)the Innovation Project of Graduate School of South China Normal University School(2019LKXM023)the Natural Science Research Project of Guangdong Food and Drug Vocational College(2019ZR01)
文摘Two-dimensional(2D)nanomaterials have captured an increasing attention in biophotonics owing to their excellent optical features.Herein,2D hafnium ditelluride(HfTe_(2)),a new member of transition metal tellurides,is exploited to support gold nanoparticles fabricating HfTe_(2)-Au nanocomposites.The nanohybrids can serve as novel 2D surface-enhanced Raman scattering(SERS)substrate for the label-free detection of analyte with high sensitivity and reproducibility.Chemical mechanism originated from HfTe_(2) nanosheets and the electromagnetic enhancement induced by the hot spots on the nano-hybrids may largely contribute to the superior SERS effect of HfTe_(2)-Au nanocomposites.Finally,HfTe_(2)-Au nanocomposites are utilized for the label-free SERS analysis of foodborne pathogenic bac-teria,which realize the rapid and ultrasensitive Raman test of Escherichia coli,Listeria mono-cytogenes,Staphylococcus aureus and Salmonella with the limit of detection of 10 CFU/mL and the maximum Raman enhancement factor up to 1.7×10^(8).Combined with principal component analysis,HfTe_(2)-Au-based SERS analysis also completes the bacterial classification without extra treatment.
基金supported by the National Natural Science Foundation of China(21905152 and 52302273)the Youth Innovation Team Project for Talent Introduction and Cultivation in Universities of Shandong Province+2 种基金the Taishan Scholar Project of Shandong Province of China(tsqn202211160 and tsqn202312199)the China Postdoctoral Science Foundation(2022M713249)the Shandong Provincial Natural Science Foundation of China(ZR2023QE176)。
文摘Carbon-based anode materials are widely used in various battery energy storage systems due to their low cost,wide source,high conductivity and easy morphology control.However,current commercially available anode materials as active materials for lithium-/sodium-ion batteries generally suffer from large volume changes and poor rate performance.In response,we synthesized defect-rich N,S co-doped two dimensional(2D)nanosheet-assembled porous carbon microspheres(N,S-PCS)via simple hydrothermal,carbonization and etching process based on the principle of Schiff base reaction.The N,S-PCS structure is thus constructed by removing Fe7S8 nanoparticles from the carbon skeleton to form porous microspheres with N,S doping.Therefore,the micromorphology characteristic,pore structure and electroconductivity of carbon materials are effectively optimized via heteroatom doping and surface engineering.As expected,the prepared N,S-PCS electrodes exhibit excellent electrochemical performance in both lithium-ion and sodium-ion batteries.For lithium-ion batteries,it achieves reversible capacities of 1045 and 237 mAh g^(-1) at 0.1 and 20 A g^(-1),respectively.For sodium-ion batteries,it shows good cycling stability with a capacity of 157 mAh g^(-1) after 500 cycles at 1 A g^(-1).Experimental and theoretical calculation results confirm that the N,S co-doping strategies help to improve the structural stability,shorten the ion diffusion paths,and promote the reaction kinetics,thus achieving excellent electrochemical performance.This work is instructive for the practical application of nonmetal doping functionalized porous carbon structures for metal-ion batteries.
基金supported by the National Natural Science Foundation of China(Nos.32071399 and 62175071)the Guangdong Basic and Applied Basic Research Foundation(Nos.2021A1515011988 and 2021A1515110265)+2 种基金the Science and Technology Program of Guangzhou(No.2019050001)the Project on the Education Department of Guangdong(Nos.2021KTSCX238 and 2022ZDZX2077)the Natural Science Research Project of Guangdong Food and Drug Vocational College(Nos.2020ZR01 and 2022ZR02).
文摘Theranostic carbon dots(CDs)have attracted widespread attention recently due to their tunable optical properties and diverse bioactivities.Beyond fluorescent imaging application,the photothermal property endows CDs with the potential for microbial inactivation.However,realization of the effective conversion between fluorescence and heat in one CD system has rarely been reported.Herein,we provide a simple strategy for targeted microbial theranostics based on 4-carboxyphenylboronic acid-derived CDs(PCBA-CDs)which possess concentration-dependent photoluminescence/photothermal features.At lower concentrations,PCBA-CDs show bright and stable fluorescent signals ranging from blue to green.The fluorescence intensity gradually decreases with increasing concentration,while on the contrary,the photothermal effect of PCBA-CDs ascends progressively due to the rearrangement of electronic transitions in aggregated CDs.PCBA-CDs also demonstrate high affinity to the polysaccharide structures on the surface of microbe which allows rapid microbial fluorescence imaging as well as specific photothermal ablation of pathogens in skin wounds using PCBA-CDs at lower and higher concentrations,respectively.This study supplies a facile nanotheranostic strategy for just-in-time microbial management using bioactive CDs.
基金National Natural Science Foundation of China(32071399,62175071)Guangdong Basic and Applied Basic Research Foundation(2021A1515011988,2021A1515110265,2022A1515012131,2022A1515140143)+2 种基金Guangdong Provincial Key Laboratory of Intelligent Disaster Prevention and Emergency Technologies for Urban Lifeline Engineering(2022B1212010016)Science and Technology Program of Guangzhou(2019050001)Open Foundation of Key Laboratory of Optoelectronic Science and Technology for Medicine(Fujian Normal University),Ministry of Education,China(JYG2009).
文摘Rapid detection of pathogens present on contaminated surfaces is crucial for food safety and public health due to the high morbidity and mortality of bacterial infections.Herein,a sensitive and efficient method for on-site identification of foodborne pathogens on anisotropic surfaces was developed by using an in situ instantaneously prepared surface-enhanced Raman scattering(SERS)platform.To achieve this,molybdenum-doped gallic acidderived carbon dots(MCDs)are utilized as the reductant for synthesizing Au@MCDs nanohybrids within just 3 s at ambient temperature.The synergistic effect of the electromagnetic enhancement and charge transfer of Au@MCDs enables excellent SERS performance 10 times stronger than bare Au NPs.The bioassay platform requires less than 5 min to complete the quantitative detection of foodborne pathogens on various microbial-contaminated interfaces with a sensitivity of 10 CFU/m L.This innovative strategy breaks the long-standing limitations of SERS substrates in practical use,such as the time-consuming process,interference of residual surfactants,poor surface stability,and few application scenarios,providing a promising tool for widespread applications in biomedical research and clinical diagnostics.
基金the Capacity Development Fund of Southwest University,China(No.SWU116007)the National Natural Science Foundation of China(Nos.61732019,61672435,61811530327,and 62032019)。
文摘In this perspective article,we first recall the historic background of human-cyber-physical systems(HCPSs),and then introduce and clarify important concepts.We discuss the key challenges in establishing the scientific foundation from a system engineering point of view,including(1)complex heterogeneity,(2)lack of appropriate abstractions,(3)dynamic black-box integration of heterogeneous systems,(4)complex requirements for functionalities,performance,and quality of services,and(5)design,implementation,and maintenance of HCPS to meet requirements.Then we propose four research directions to tackle the challenges,including(1)abstractions and computational theory of HCPS,(2)theories and methods of HCPS architecture modelling,(3)specification and verification of model properties,and(4)software-defined HCPS.The article also serves as the editorial of this special section on cyber-physical systems and summarises the four articles included in this special section.
基金Authors Qinglin LIAN,Xi WANG,and Zhiming LIU would like to acknowledge the National Key R&D Program of China(2016YFB1200501-008)for the financial support.Author Hongtao ZHU would like to acknowledge the support of Australian Research Council Training Centre for Advanced Technologies in Rail Track Infrastructure(ARC ITTC-Rail).
文摘The existence of narrow and brittle white etching layers(WELs)on the rail surface is often linked with the formation of rail defects such as squats and studs,which play the key roles in rail surface degradation and tribological performance.In the present study,a systematic investigation on stress/strain distribution and fatigue life of the WEL during wheel-rail rolling contact was conducted based on a numerical model considering the realistic wheel geometry.This is the first study considering the influence of rail materials,loading pressure,frictional condition,WEL geometry(a/b),and slip ratio(Sr)in the practical service conditions at the same time.The results revealed much higher residual stress in WEL than in rail matrix.Stress changes along the rail depth matched with the previously reported microstructure evolutions.The current work revealed that the maximum difference in contact stress between the wheel passages of rail matrix and the WEL region(noted as stress variation)rises with the increase of loading pressure,the value of a/b,and Sr;but drops with the friction coefficient(μ).In addition,a critical length–depth ratio of 5 for a/b has been found.The fatigue parameter,FP,of the WEL decreased quickly with the length–depth ratio when it was less than 5 and then increased slightly when it was larger than 5.This study also revealed that the fatigue life of the WEL was reduced for high strength head hardened(HH)rail compared with standard carbon(SC)rail.
基金supported by the National Natural Science Foundation of China(Nos.21876009,21677008)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019A18)the Fundamental Research Funds for the Central Universities(Nos.JD2110,PY2103).
文摘Red mud,as a solid waste produced during the alumina production,can cause severe ecoenvironmental pollution and health risks to human.Therefore,the resourcing of this type of solid waste is an effective way for the sustainable development.This paper reviews the recent progress on red mud-based catalysts for the removal of typical air pollutants,such as the catalytic reduction of nitrogen oxides(NO_(x))by NH_(3)(NH_(3)-SCR)and the catalytic oxidation of CO and volatile organic compounds(VOCs).The factors influencing the catalytic performance and the structure–activity relationship have been discussed.Future prospects and directions for the development of such catalysts are also proposed.This review would benefit for the high value-added utilizations of red mud in mitigating atmospheric pollutions.
