Inhibitory effect of procyanidin B2 and tannin acid on cholesterol esterase and their synergistic effect with orlistat

This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were investigated by enzymatic kinetics,multi-spectroscopy methods,thermodynamics analysis,molecular docking,and dynamic simulations.PC and TA could bind with CEase and inhibit the activity of enzyme in a mixed-competitive manner and non-competitive manner,which was verified by molecular docking simulations and dynamics simulations.Also,PC and TA showed the synergistic inhibition with orlistat.Fluorescence,UVvis and the thermodynamic analysis revealed that the complexes were formed from CEase and inhibitors by noncovalent interaction.As revealed by the circular dichroism results,both PC and TA decreased enzymatic activities by altering the conformations of CEase.The inhibition of PC and TA on CEase might be one mechanism for its cholesterol-lowering effect.

Synergistic effects of the entomopathogenic fungus Isaria javanica and low doses of dinotefuran on the efficient control of the rice pest Sogatella furcifera

The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly used chemical insecticides.We investigated the effects of the insect fungal pathogen Isaria javanica,alone and in combination with the chemical insecticide dinotefuran,on S.furcifera under both laboratory and field conditions.Our results show that I.javanica displays high infection efficiency and mortality for different stages of S.furcifera,reducing adult survival,female oviposition and ovary development.Laboratory bioassays showed that the combined use of I.javanica with a low dose(4-16 mg L^(-1))of dinotefuran resulted in higher mortality in S.furcifera than the use of I.javanica or dinotefuran alone.The combined treatment also had more significant effects on several host enzymes,including superoxide dismutase,catalase,peroxidase,and prophenol oxidase activities.In field trials,I.javanica effectively suppressed populations of rice planthoppers to low levels(22-64%of the level in untreated plots).Additional field experiments showed synergistic effects,i.e.,enhanced efficiency,for the control of S.furcifera populations using the combination of a low dose of I.javanica(1×10^(4) conidia mL^(-1))and a low dose of dinotefuran(~4.8-19.2%of normal field use levels),with control effects of>90%and a population level under 50 insects per 100 hills at 3-14 days post-treatment.Our findings indicate that the entomogenous fungus I.javanica offers an attractive biological control addition as part of the integrated pest management(IPM)practices for the control of rice plant pests.

Synergistic effect of heterogeneous single atoms and clusters for improved catalytic performance

Electrocatalytic water splitting provides an efficient method for the production of hydrogen.In electrocatalytic water splitting,the oxygen evolution reaction(OER)involves a kinetically sluggish four-electron transfer process,which limits the efficiency of electrocatalytic water splitting.Therefore,it is urgent to develop highly active OER catalysts to accelerate reaction kinetics.Coupling single atoms and clusters in one system is an innovative approach for developing efficient catalysts that can synergistically optimize the adsorption and configuration of intermediates and improve catalytic activity.However,research in this area is still scarce.Herein,we constructed a heterogeneous single-atom cluster system by anchoring Ir single atoms and Co clusters on the surface of Ni(OH)_(2)nanosheets.Ir single atoms and Co clusters synergistically improved the catalytic activity toward the OER.Specifically,Co_(n)Ir_(1)/Ni(OH)_(2)required an overpotential of 255 mV at a current density of 10 mA·cm^(−2),which was 60 mV and 67 mV lower than those of Co_(n)/Ni(OH)_(2)and Ir1/Ni(OH)_(2),respectively.The turnover frequency of Co_(n)Ir_(1)/Ni(OH)_(2)was 0.49 s^(−1),which was 4.9 times greater than that of Co_(n)/Ni(OH)_(2)at an overpotential of 300 mV.

Synergistic effects of three traditional herbs green tea,mulberry leaf and corn silk on glucose uptake level of L6 myoblasts and the hypoglycemic mechanism

Background:Green tea,mulberry leaf and corn silk are traditional herbs used in the prevention and treatment of diabetes in China for a long time,but their synergistic hypoglycemic effects and mechanisms remain unclear.Methods:The effective components of green tea,mulberry leaf and corn silk were extracted and enriched.Mixture design of experiments was used to study the influences of different combinations on the cell viability and glucose uptake level of L6 myoblasts,so as to determine the optimal synergistic hypoglycemic combination.The possible hypoglycemic mechanism of the optimal synergistic combination was explored by cytotoxicity assay,glucose uptake assay,and western blot.Results:Three polyphenol enrichment fractions of the herbs,30%ethanol elution fraction of green tea(GT),50%ethanol elution fraction of mulberry leaf(ML)and 60%ethanol elution fraction of corn silk(CS)were obtained.The antioxidant activities of GT-30%,ML-50%and CS-60%were superior to those of crude extracts,and showed strong potential inα-amylase andα-glucosidase inhibition activities.The optimal synergistic combination of crude extracts G7(crude extract of green tea:crude extract of mulberry leaf:crude extract of corn silk=1:5:3),polyphenol enrichment fractions R3(GT-30%:ML-50%:CS-60%=1:7:1)and monomers X2(epigallocatechin gallate:morusin:formononetin=3:1:2)were selected,respectively.G7,R3,and X2 showed promoting effects on the cell viability and glucose uptake of L6 myoblasts within the detected concentration range.In addition,G7,R3,and X2 could increase the expression levels of p-PI3K/PI3K and p-Akt/Akt in L6 myoblasts,and promote the translocation of Glut4,but G7 and R3 showed more significant effects.Conclusion:The synergistic hypoglycemic effects of green tea,mulberry leaf and corn silk had the characteristics of multiple-components and multiple-targets with p-PI3K/PI3K,p-Akt/Akt and the translocation of Glut4 signal pathways involved.The three traditional herbs might have the potential to be combined used for the prevention and treatment of diabetes based on the synergistic hypoglycemic effects.

Synergistic effect of pinellia total alkaloids and uncaria total alkaloids on anticonvulsant action in mice and rats

Aim To investigate the synergistic effect of the combination of pinellia total alkaloid （PTA） and uncaria total alkaloid （UTA）, and explore the mechanism of anticonvulsant action. Methods Anticonvulsant and toxic effect profiles of combinations of PTA with UTA, alone and at three fixed ratios of 1：4, 1 ：1, 4：1, were evaluated in maximal electroshock （MES）-induced seizures and acute toxicity test in mice. Respective ED50 and LD50 were calculated with Bliss＇s method. Their synergistic effect were evaluated by isobolographic analysis and allowed the determination of benefit indices （BI） for respective combinations. The model of convulsive rats kindled by penicillin topically injected into cortex was used to investigated the content of Glu, Asp, Gly and GABA in hippocampus using high performance liquid chromatography （HPLC）. Results Combinations of PTA and UTA at the ratio of 4：1 were synergistic in MES test and antagonistic in acute toxicity test, showing the best profile for combinations of PTA with UTA. In contrast, the ratios of 1 ：4 and 1 ： 1, despite synergistic in MES test, were additive in acute toxicity test. The 4：1 combination and two drugs alone significantly decreased Glu level and increased GABA level in the hippocampus, but the GABA level in the 4：1 combination group was higher than that in the two drugs alone groups. They did not have significant influence on the levels of ASp and Gly. Conclusion Combinations of PTA and UTA at 4：1 ratio demonstrated synergistic effect in anticonvulsant action and antagonistic effect in toxicity. The anticonvulsant mechanism might be related to decreasing the excitability of Glutamatergic neurons and increasing the inhibition of GABAergic neurons.

Research on large-scale cascading failure of power systems using synergistic effect

This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the complex network theory the vulnerability of the power system can be evaluated by the minimum load loss rate when considering power supply ability.Consequently according to the synergistic effect theory the critical line of the power system is defined by its influence on failure set vulnerability in N-k contingencies.The cascading failure modes are proposed based on the criterion whether the acceptable load curtailment level is below a preset value.Significant conclusions are revealed by results of IEEE 39 case analysis weak points of power networks and heavy load condition are the main causes of large-scale cascading failures damaging synergistic effects can result in partial failure developed into large-scale cascading failures vulnerable lines of power systems can directly lead the partial failure to deteriorate into a large blackout while less vulnerable lines can cause a large-scale cascading failure.

Synergistic Effect of Cottonseed Oil EC and Soybean Oil EC on Imidacloprid and Avermectin

[Objective] The study aimed to investigate the synergistic effect of vegetable oil EC on chemical pesticides. [Method] Cottonseed oil EC and soybean oil EC were mixed with 20% imidacloprid EC and 0.5% avermectin WE respectively, Schizaphis graminum were handled with dipped method,synergistic effects of vegetable oil EC on imidacloprid and avermectin were analyzed. [Result] Cottonseed oil EC and soybean oil EC had obvious synergistic effect on 20% imidacloprid EC and 0.5% avermectin WE. Corrected mortality of 20% imidacloprid EC＋cottonseed oil EC（0.10＋10.00, 0.10＋5.00, 0.10＋3.33 and 0.05＋10.00 ml/L）, 0.5% avermectin WE＋cottonseed oil EC（1.00＋10.00, 1.00＋5.00, 0.50＋10.00 and 0.50＋5.00 ml/L）and 20% imidacloprid EC＋soybean oil EC（0.10＋10.00, 0.10＋5.00, 0.10＋10.00 and 0.05＋5.00 ml/L） were all over 90%. [Conclusion] Considered from control effect and economy angle, the mixture of cottonseed oil EC or soybean oil EC with 20% imidacloprid EC, and the mixture of cottonseed oil EC with 0.5% avermectin WE could be used to control S. graminum.

Synergistic effects in N‐K_2Ti_4O_9/UiO‐66‐NH_2 composites and their photocatalysis degradation of cationic dyes

N-K2Ti4O9/UiO-66-NH2 composites synthesized by a facile solvothermal method have a core-shell structure with UiO-66-NH2 forming the shell around a N-K2Ti4O9 core.Their photocatalytic activities in the degradation of dyes under visible light irradiation were investigated.The N-K2Ti4O9/UiO-66-NH2 composites exhibited higher photocatalytic activity than the pure components.This synergistic effect was due to the high adsorption capacity of UiO-66-NH2 and that the two components together induced an enhanced separation efficiency of photogenerated electron-hole pairs.The mass ratio of N-K2Ti4O9 to ZrCl4 of 3：7 in the composite exhibited the highest photocatalytic activity.Due to the electrostatic attraction between the negatively charged backbone of UiO-66-NH2with the positively charged groups of cationic dyes,the composites were more photocatalytically active for cationic dyes than for anionic dyes.

Numerical Investigation on 1,3-Butadiene/Propyne Co-pyrolysis and Insight into Synergistic Effect on Aromatic Hydrocarbon Formation

A numerical investigation on the co-pyrolysis of 1,3-butadiene and propyne is performed to explore the synergistic effect between fuel components on aromatic hydrocarbon formation. A detailed kinetic model of 1,3-butadiene/propyne co-pyrolysis with the sub-mechanism of aromatic hydrocarbon formation is developed and validated on previous 1,3-butadiene and propyne pyrolysis experiments. The model is able to reproduce both the single component pyrolysis and the co-pyrolysis experiments, as well as the synergistic effect between 1,3- butadiene and propyne on the formation of a series of aromatic hydrocarbons. Based on the rate of production and sensitivity analyses, key reaction pathways in the fuel decomposition and aromatic hydrocarbon formation processes are revealed and insight into the synergistic effect on aromatic hydrocarbon formation is also achieved. The synergistic effect results from the interaction between 1,3-butadiene and propyne. The easily happened chain initiation in the 1,3-butadiene decomposition provides an abundant radical pool for propyne to undergo the H-atom abstraction and produce propargyl radical which plays key roles in the formation of aromatic hydrocarbons. Besides, the 1,3-butadiene/propyne co-pyrolysis includes high concentration levels of C3 and C4 precursors simultaneously, which stimulates the formation of key aromatic hydrocarbons such as toluene and naphthalene.

The 2020/21 Extremely Cold Winter in China Influenced by the Synergistic Effect of La Niña and Warm Arctic

In the first half of winter 2020/21,China has experienced an extremely cold period across both northern and southern regions,with record-breaking low temperatures set in many stations of China.Meanwhile,a moderate La Niña event which exceeded both oceanic and atmospheric thresholds began in August 2020 and in a few months developed into its mature phase,just prior to the 2020/21 winter.In this report,the mid−high-latitude large-scale atmospheric circulation anomalies in the Northern Hemisphere,which were forced by the negative phase of Arctic Oscillation,a strengthened Siberian High,an intensified Ural High and a deepened East Asian Trough,are considered to be the direct reason for the frequent cold surges in winter 2020/21.At the same time,the synergistic effect of the warm Arctic and the cold tropical Pacific(La Niña)provided an indispensable background,at a hemispheric scale,to intensify the atmospheric circulation anomalies in middle-to-high latitudes.In the end,a most recent La Niña prediction is provided and the on-coming evolution of climate is discussed for the remaining part of the 2020/21 winter for the purpose of future decision-making and early warning.

Synergistic effect of fatty liver and smoking on metabolic syndrome

AIM:To investigate the association of fatty liver and smoking on metabolic syndrome and its components.METHODS:This cross-sectional study enrolled participants who attended annual health screening at Shin Kong Wu Ho-Su Memorial Hospital from January to December 2005.A total of 3455(1981 men and 1474 women) subjects were included in final analyses.Fatty liver was diagnosed using abdominal ultrasonography by trained gastroenterologists.The modified National Cholesterol Education Program Adult Treatment Panel Ⅲ was used to define metabolic syndrome.The associations between smoking,fatty liver and metabolic syndrome were analyzed using multiple logistic regression.RESULTS:Subjects with fatty liver,and who smoked tobacco,had the highest odds ratios(ORs) for high waist circumference [OR,4.5(95% CI:3.3-6.1) ,P < 0.05],hypertriglyceridemia [OR,8.1(95% CI:6.0-10.9) ,P < 0.05],low serum high-density lipoprotein cholesterol(HDL-C) [OR,8.3(95% CI:6.1-11.3) ,P < 0.05],and metabolic syndrome [OR,9.5(95% CI:6.7-13.4) ,P < 0.05] compared to subjects without fatty liver who did not smoke tobacco.We also found that the ORs for hypertriglyceridemia,low serum HDL-C,and metabolic syndrome for subjects with fatty liver who smoked tobacco had greater than the sum of the ORs for subjects with fatty liver who did not smokeplus those who did not have fatty liver and who did smoke.CONCLUSION:Fatty liver and smoking had a synergistic effect on metabolic syndrome and its components,especially for hypertriglyceridemia and low serum HDL-C.

Synergistic effect of additives on electrodeposition of copper from cyanide-free electrolytes and its structural and morphological characteristics

Electrodeposition of acid copper plating on mild steel substrate is tedious due to the galvanic displacement reaction ofcopper on mild steel.This can be avoided by using a proper complexing agent,because the complexing agent tuned the potential ofnoble direction to less noble direction by complex formation.In this paper,environment friendly electrodeposition of copper fromnon-cyanide electrolyte using sodium gluconate as complexing agent was investigated in alkaline medium.The effects of additivessuch as1,2,3-benzotriazole,sodium lauryl sulphate,PEG8000and saccharin were studied.These additives are found to reduce thegrain size,grain boundaries and improve surface morphology of the copper deposits.Also they improve the throwing power of thedepositing electrolytes and hardness of deposits.The electrodeposited copper coatings were characterized by X-ray diffractiontechnique.XRD results indicate that the electrodeposited copper shows polycrystalline and face centered cubic structure.The crystalsize was calculated by XRD and AFM analysis.Among these additives studied,the mixture of benzotriazole and sodium laurylsulphate acts as the best additive.A uniform pore-free surface observed under SEM and AFM results reveal the grain refining broughtabout by the additives.

Synergistic effect between Sn and K promoters on supported platinum catalyst for isobutane dehydrogenation

Catalytic dehydrogenation of isobutane has recently received considerable attention because of the increasing demand for isobutene.In this study,the synergistic effect between Sn and K on PtSnK/γ-Al2O3 catalysts has been investigated by changing the content of Sn.It was found that with the presence of potassium,suitable addition of Sn could not only increase the metal dispersion,but also reduce the catalyst acidity.In these cases,the synergistic effect could also strengthen the interactions between the metal and support,which resulted in an increase in both catalytic activity and stability.In our experiments,Pt-0.6SnK/Al catalyst exhibited the lowest deactivation rate （12.4%） and showed a selectivity to isobutene higher than 94% at the isobutane conversion of about 45.3% after running the reaction for 6 h.However,with the excessive loading of Sn,surface property of active sites and the interactions between metal and support were changed.As a result,the initial optimal ratio between the metallic function and acid function would be destroyed,which was disadvantageous to the reaction.

Synergistic effect of MXene on the flame retardancy and thermal degradation of intumescent flame retardant biodegradable poly(lactic acid)composites

The effect of Ti3C2 MXene nanosheets on the intumescent flame retardant(IFR)poly(lactic acid)(PLA)composites was investigated among a series of PLA/IFR/MXene,which were prepared by melt blending 0-2.0 wt%MXene,10.0 wt%-12.0 wt%IFR and PLA together.The results of limiting oxygen index(LOI)and vertical burning(UL-94)discover that the combination of 0.5 wt%MXene and 11.5 wt%IFR synergistically improves the fire safety of PLA to reach UL-94 V-0 rating with LOI value of 33.0%.The PLA/IFR/MXene composites perform an obvious reduction in peak of heat release rate(HRR)in cone calorimeter tests(CCTs).Furthermore,the carbon residues after CCTs were characterized by scanning electron microscope(SEM),laser Raman spectroscopy(LRS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).It is demonstrated that both the titanium composition of the MXene structure and the characteristics of the two-dimensional material enhance the PLA/IFR/MXene composite materials’ability to produce a dense barrier layer to resist burnout during thermal degradation.

Synergistic Effects of Nitrogen Amendments and Ethylene on Atmospheric Methane Uptake under a Temperate Old-growth Forest

An increase in atmospheric nitrogen （N） deposition can promote soil acidification, which may increase the release of ethylene （C2H4） under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane （CH4） uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of （NH4）2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH＋4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH＋4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4＋ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.

Synergistic effects of vegetation layers of maize and potato intercropping on soil erosion on sloping land in Yunnan Province, China

Intercropping, as an overyielding system, can decrease soil erosion on sloping land through the presence of dense canopy covers. However, the structure mechanism in canopy is still unclear. We conducted a two-year field experiment on runoff plots, exploring whether the interaction between vegetation layers reduce soil erosion in maize and potato intercropping systems. The maize, potato, and weed layers in the intercropping system were removed by a single layer, two layers and three layers, respectively(total of 8 treatments including all layers removed as the control). Then, throughfall, runoff and sediment were measured at the plot and row scale on a weekly basis. Based on the difference between each treatment and the control, we calculated and found a relative reduction of runoff and sediment by any combination of the two vegetation layers greater than the sum of each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 15.65% and 46.73%, respectively. Sediment loss decreased by 33.96% and 42.77%, respectively. Moreover, runoffand sediment reduced by the combination of all vegetation layers(no layers removed) was also larger than the sum of that by each single layer. In 2016 and 2017, the highest relative reduction of runoff reached 7.32% and 3.48%, respectively. So, there were synergistic effects among multi-level(two or three layers) vegetation layers in terms of decreasing soil erosion on sloping land. Maize redistributes more throughfall at the maize intra-specific row and the maize and potato inter-specific, which is favorable for the synergistic effect of reducing soil erosion. This finding shows an important mechanism of maize and potato intercropping for soil and water conservation, and may promote the application of diverse cropping systems for sustainable agriculture in mountainous areas.

Experimental Study of Vacuum Ultraviolet Radiation Effects and Its Synergistic Effects with Atomic Oxygen on a Spacecraft Material-Polytetrafluoroethylene

Polytetrafluoroethylene (Teflon), a widely used spacecraft material, isstudied to investigate the vacuum ultraviolet (VUV) effects and its synergistic effects with atomicoxygen (AO) in a ground-based simulation facility. The samples before and after the experiments arecompared in appearance, mass, optical properties and surface composition. The reactioncharacteristics of Teflon are summarized and the reaction mechanisms are analyzed. The followingconclusion can be drawn: at the action of VUV the Teflon sample surface is darkened for theaccumulation of carbon; and when the sample is exposed to AO, the carbon is oxidized and thedarkening surface is bleached; the synergistic effects of VUV and AO may cause the erosion of Teflonmore severe.

Synergistic Effect of Cation and Anion for Low-Temperature Aqueous Zinc-Ion Battery

Although aqueous zinc-ion batteries have gained great development due to their many merits,the frozen aqueous electrolyte hinders their practical application at low temperature conditions.Here,the synergistic e ect of cation and anion to break the hydrogen-bonds network of original water molecules is demonstrated by multi-perspective characterization.Then,an aqueous-salt hydrates deep eutectic solvent of 3.5 M Mg(ClO_(4))_(2)+1 M Zn(ClO_(4))_(2)is proposed and displays an ultralow freezing point of-121℃.A high ionic conductivity of 1.41 mS cm-1 and low viscosity of 22.9 mPa s at-70℃ imply a fast ions transport behavior of this electrolyte.With the benefits of the low-temperature electrolyte,the fabricated Zn||Pyrene-4,5,9,10-tetraone(PTO)and Zn||Phenazine(PNZ)batteries exhibit satisfactory low-temperature performance.For example,Zn||PTO battery shows a high discharge capacity of 101.5 mAh g^(-1)at 0.5 C(200 mA g^(-1))and 71 mAh g^(-1)at 3C(1.2 A g^(-1))when the temperature drops to-70℃.This work provides an unique view to design anti-freezing aqueous electrolyte.

Synergistic effect of microwave irradiation and CaF2 on vanadium leaching

The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride （CaF2） on the vana- dium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when CaF2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%-15% when 5wt% CaF2 is added; by contrast, in the absence of CaF2, the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation, whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover, a large amount of A1 and V and a small amount of Si are dissolved from samples under microwave heating, as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When CaF2 is present, the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer, resulting in a prominent effect of mi- crowave irradiation.

Synergistic effects of multiple driving factors on the runoff variations in the Yellow River Basin,China

River runoff plays an important role in watershed ecosystems and human survival,and it is controlled by multiple environmental factors.However,the synergistic effects of various large-scale circulation factors and meteorological factors on the runoff on different time-frequency scales have rarely been explored.In light of this,the underlying mechanism of the synergistic effects of the different environmental factors on the runoff variations was investigated in the Yellow River Basin of China during the period 1950-2019 using the bivariate wavelet coherence(WTC)and multiple wavelet coherence(MWC)methods.First,the continuous wavelet transform(CWT)method was used to analyze the multiscale characteristics of the runoff.The results of the CWT indicate that the runoff exhibited significant continuous or discontinuous annual and semiannual oscillations during the study period.Scattered inter-annual time scales were also observed for the runoff in the Yellow River Basin.The meteorological factors better explained the runoff variations on seasonal and annual time scales.The average wavelet coherence(AWC)and the percent area of the significant coherence(PASC)between the runoff and individual meteorological factors were 0.454 and 19.89%,respectively.The circulation factors mainly regulated the runoff on the inter-annual and decadal time scales with more complicated phase relationships due to their indirect effects on the runoff.The AWC and PASC between the runoff and individual circulation factors were 0.359 and 7.31%,respectively.The MWC analysis revealed that the synergistic effects of multiple factors should be taken into consideration to explain the multiscale characteristic variations of the runoff.The AWC or MWC ranges were 0.320-0.560,0.617-0.755,and 0.819-0.884 for the combinations of one,two,and three circulation and meteorological factors,respectively.The PASC ranges were 3.53%-33.77%,12.93%-36.90%,and 20.67%-39.34%for the combinations one,two,and three driving factors,respectively.The combinations of precipitation,evapotranspiration(or the number of rainy days),and the Arctic Oscillation performed well in explaining the variability in the runoff on all time scales,and the average MWC and PASC were 0.847 and 28.79%,respectively.These findings are of great significance for improving our understanding of hydro-climate interactions and water resources prediction in the Yellow River Basin.