In the petrochemical industry process, the relative volatility between the components to be separated is close to one or the azeotrope that systems are difficult to separate. Liquid-liquid extraction is a common and e...In the petrochemical industry process, the relative volatility between the components to be separated is close to one or the azeotrope that systems are difficult to separate. Liquid-liquid extraction is a common and effective separation method, and selecting an extraction agent is the key to extraction technology research. In this paper, a design method of extractants based on elements and chemical bonds was proposed. A knowledge-based molecular design method was adopted to pre-select elements and chemical bond groups. The molecules were automatically synthesized according to specific combination rules to avoid the problem of “combination explosion” of molecules. The target properties of the extractant were set, and the extractant meeting the requirements was selected by predicting the correlation physical properties of the generated molecules. Based on the separation performance of the extractant in liquid-liquid extraction and the relative importance of each index, the fuzzy comprehensive evaluation membership function was established, the analytic hierarchy process determined the mass ratio of each index, and the consistency test results were passed. The results of case study based on quantum chemical analysis demonstrated that effective determination of extractants for the analysis of benzene-cyclohexane systems. The results unanimously prove that the method has important theoretical significance and application value.展开更多
The international Argo program,a global observational array of nearly 4000 autonomous profiling floats initiated in the late 1990s,which measures the water temperature and salinity of the upper 2000 m of the global oc...The international Argo program,a global observational array of nearly 4000 autonomous profiling floats initiated in the late 1990s,which measures the water temperature and salinity of the upper 2000 m of the global ocean,has revolutionized oceanography.It has been recognized one of the most successful ocean observation systems in the world.Today,the proposed decade action“OneArgo”for building an integrated global,full-depth,and multidisciplinary ocean observing array for beyond 2020 has been endorsed.In the past two decades since 2002,with more than 500 Argo deployments and 80 operational floats currently,China has become an important partner of the Argo program.Two DACs have been established to process the data reported from all Chinese floats and deliver these data to the GDACs in real time,adhering to the unified quality control procedures proposed by the Argo Data Management Team.Several Argo products have been developed and released,allowing accurate estimations of global ocean warming,sea level change and the hydrological cycle,at interannual to decadal scales.In addition,Deep and BGC-Argo floats have been deployed,and time series observations from these floats have proven to be extremely useful,particularly in the analysis of synoptic-scale to decadal-scale dynamics.The future aim of China Argo is to build and maintain a regional Argo fleet comprising approximately 400 floats in the northwestern Pacific,South China Sea,and Indian Ocean,accounting for 9%of the global fleet,in addition to maintaining 300 Deep Argo floats in the global ocean(25%of the global Deep Argo fleet).A regional BGC-Argo array in the western Pacific also needs to be established and maintained.展开更多
The design of efficient and low-cost multifunctional electrocatalysts for hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) is critical for the development of clean en...The design of efficient and low-cost multifunctional electrocatalysts for hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) is critical for the development of clean energy. Two-dimensional(2D) carbon-based nano-materials are becoming more and more popular in heterogeneous catalysis due to their cost-effective and multi-scale tunability as single-atom catalysis(SACs) substrates. In this paper, by using first-principles calculation, we designed and demonstrated a novel macropore T-carbon [110](TC) monolayer as 2D electrocatalyst substrate for HER/OER/ORR, and the synergistic modification of the transition metal and nonmetal atoms(TM-X) were investigated to enhance the multifunctional electrocatalytic performance. We screened out the Co embedded in N-doped TC(Co3@N-TC) from 30 TM@X-TC monolayers as a trifunctional electrocatalysts, which exhibits superior performance for HER/ORR/OER on both thermodynamic and kinetic scales, and with excellent thermal and electrochemical stability. Then, the TC monolayer is naturally macropore with a diameter of 5.36 A and exhibits excellent adsorption capacity for the intermediates and products of the redox reactions. Moreover, we revealed the origin of the electrocatalytic activity using the crystal orbital Hamilton population(COHP) and the molecular orbitals(MOs). The d orbital of Co3@N-TC is significantly hybridized with the p orbital of the intermediates, so that the lone electrons initially occupied in the antibonding state pair up and occupy the downward bonding state, allowing *OH to be appropriately adsorbed onto the TC monolayer. This work not only demonstrates that the TM@X-TC monolayer is a superior synergistic trifunctional electrocatalyst, but also reveals a macropore monolayer material with potential applications in electrocatalysis.展开更多
Rose is sensitive to high temperature which will make the rose go into a semi-dormancy state.Grafting is an excellent way to enhance rose heat tolerance.Here,heat-tolerant Rosa multiflora‘Huanong Wuci 1'(W)and he...Rose is sensitive to high temperature which will make the rose go into a semi-dormancy state.Grafting is an excellent way to enhance rose heat tolerance.Here,heat-tolerant Rosa multiflora‘Huanong Wuci 1'(W)and heat-sensitive Rosa chinensis‘Old Blush’(X)were selected as experimental materials.The RNA-seq technique was used to investigate the transcriptomes of self-root grafting line(XX0),heterogeneous grafting line(XW0),self-root grafting line under 6 h heat stress(XX6),and heterogeneous grafting line under 6 h heat stress(XW6).Under high temperature stress,multiple signaling pathways were activated,moreover,a large number of transcription factors and functional genes were induced,especially the HSFs and HSPs with remarkably upregulated expression levels.The GO analysis showed that the differences in the expressions of the genes related to fatty acids and carbohydrates were observed between self-root grafting line and heterogeneous grafting line.In addition,14 P450s were differentially expressed,and one lectin gene was up-regulated in XW0 vs XW6,but down-regulated in XX0 vs XX6.Considering physiological and biochemical traits such as relative electrolyte leakage,SOD activity,proline,and total soluble sugars,DEGs involved in these processes may be key factors to resist high temperature.The present study provides an insight into the complex mechanism underlying grafting in response to heat stress.Our results indicate that grafting is an effective way to improve rose heat resistance.展开更多
Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated 9(CRISPR/Cas9)system has recently become one popular technology due to its efficiency,precision,and simplicity compared with other genome edi...Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated 9(CRISPR/Cas9)system has recently become one popular technology due to its efficiency,precision,and simplicity compared with other genome editing tools such as Zinc Finger Nucleases(ZFNs)and Transcription Activator Like Effector Nucleases(TALENs).Horticultural crops provide energy and health-keeping nutrients to humankind.Genome-editing technology has become widely adopted in horticultural breeding with the increasing demand for high yield and better-quality horticultural crops.Here,we describe the CRISPR/Cas9 system construction,its optimization,including sgRNA promoter,sgRNA design,Cas9 protein promoter,SpCas9 variants and orthologs,and vector delivery methods.We also summarized the application of this technology in horticultural plants for stress responses enhancement,fruit quality improvement,and cultivation traits modification.This detailed review was compiled to help establish comprehensive understanding of the CRISPR/Cas9 systems and provide a reference for further developing this technology to manipulate horticultural plant traits effectively.展开更多
Pseudorabies virus glycoprotein E （PRV gE） has been recognized as a suitable diagnostic antigen for pseudorabies. In order to produce gE antigen in large quantities and at low cost, a gene fragment encoding PRV gE c...Pseudorabies virus glycoprotein E （PRV gE） has been recognized as a suitable diagnostic antigen for pseudorabies. In order to produce gE antigen in large quantities and at low cost, a gene fragment encoding PRV gE core epitopes was expressed in E. coli BL21 expression system. SDS-PAGE and Western Blotting revealed that the expression product in culture supematant of E. coli BL21 was a recombinant protein, approximately 51.8 Kd. At 5 h post-induction, protein concentration assay showed that the expression product amounted to 1.65 mg/ml, accounting for 24. 17% of total proteins in the culture supematant. An indirect PRV gE-ELISA was established by using the recombinant expression product as a coating antigen. Cross-reactivity assay showed that this antigen was PRV specific. In addition, the assay was consistently reproducible. Comparison of detection results of 240 serum samples between PRV gE-ELISA and a commercially available PRV diagnostic kit showed that there was no significant difference between these two methods （P 〉 0.05 ）.展开更多
This study sought to elucidate the genetic correlation of cerebral venous sinus thrombosis caused by a hereditary antithrombin deficiency in a Chinese family, at the genetic and protein levels. A nonsense mutation fro...This study sought to elucidate the genetic correlation of cerebral venous sinus thrombosis caused by a hereditary antithrombin deficiency in a Chinese family, at the genetic and protein levels. A nonsense mutation from C to T on locus 6431 in exon 3B of the antithrombin gene was observed, leading to an arginine （CGA） to stop codon （TGA） change in the protein. This is the first report of this mutation in China. Ineffective heparin therapy in the propositus patient is associated with a lack of heparin binding sites after antithrombin gene mutation. Characteristic low intracranial pressure in the acute phase might be specific to this patient with cerebral venous sinus thrombosis.展开更多
The current lack of high-precision information on subsurface seawater is a constraint in fishery research.Based on Argo temperature and salinity profiles,this study applied the gradient-dependent optimal interpolation...The current lack of high-precision information on subsurface seawater is a constraint in fishery research.Based on Argo temperature and salinity profiles,this study applied the gradient-dependent optimal interpolation to reconstruct daily subsurface oceanic environmental information according to fishery dates and locations.The relationship between subsurface information and matching yellowfin tuna(YFT)in the western and central Pacific Ocean(WCPO)was examined using catch data from January 1,2008 to August 31,2017.The seawater temperature and salinity results showed differences of less than±0.5°C and±0.01 compared with the truth observations respectively.Statistical analysis revealed that the most suitable temperature for YFT fishery was 28–29°C at the near-surface.The most suitable salinity range for YFT fishery was 34.5–36.0 at depths shallower than 300 m.The suitable upper and lower bounds on the depths of the thermocline were 90–100 m and 300–350 m,respectively.The thermocline characteristics were prominent,with a mean temperature gradient exceeding 0.08°C/m.These results indicate that the profiles constructed by gradient-dependent optimal interpolation were more accurate than those of the nearest profiles adopted.展开更多
Argo has become an important constituent of the global ocean observation system.However,due to the lack of sea surface measurements from most Argo profiles,the application of Argo data is still limited.In this study,a...Argo has become an important constituent of the global ocean observation system.However,due to the lack of sea surface measurements from most Argo profiles,the application of Argo data is still limited.In this study,a thermocline model was constructed based on three key thermocline parameters,i.e,thermocline upper depth,the thermocline bottom depth,and thermocline temperature gradient.Following the model,we estimated the sea surface temperature of Argo profiles by providing the relationship between sea surface and subsurface temperature.We tested the effectiveness of our proposed model using statistical analysis and by comparing the sea surface temperature with the results obtained from traditional methods and in situ observations in the Pacific Ocean.The root mean square errors of results obtained from thermocline model were found to be significantly reduced compared to the extrapolation results and satellite retrieved temperature results.The correlation coefficient between the estimation result and in situ observation was 0.967.Argo surface temperature,estimated by the thermocline model,has been theoretically proved to be reliable.Thus,our model generates theoretically feasible data present the mesoscale phenomenon in more detail.Overall,this study compensates for the lack surface observation of Argo,and provides a new tool to establish complete Argo data sets.展开更多
In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanopartic...In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanoparticles prepared by this method were evaluated for healing wounds in rats with diabetes.We also attempted to determine the underlying mechanism and influencing factors of the silver nanomaterial preparation method.Compared with growth factors,silver nanoparticles exhibit better healing effects for rats with diabetes.No remnant silver ions were detected in the major organs of these rats after the application of silver nanoparticles.Silver nanoparticles prepared using CMCS are less toxic than those prepared from the conventional method,promote the proliferation of skin fibroblasts,and are promising as a topical medication for infected wounds.An obvious breakage process of the particles is observed during the growth of nanocrystalline silver in CMCS.In this study,we also attempted to determine whether this method is suitable for synthesizing silver nanoparticles using N-trimethyl chitosan chloride and sodium alginate were used in this particular experiment.The characteristic UV-vis absorbance peak of silver nanoparticles was found only in the reaction mixture containing N-trimethyl chitosan chloride.Our study demonstrates that free radicals are the key factor in this silver nanoparticle preparation method.展开更多
Metastasis is the main cause of death in cancer patients. To improve the outcomes of patients undergoing a surgery, new adjuvant therapies that can effectively inhibit metastases have to be developed. Studies have sho...Metastasis is the main cause of death in cancer patients. To improve the outcomes of patients undergoing a surgery, new adjuvant therapies that can effectively inhibit metastases have to be developed. Studies have shown that flavonoid naringenin, a natural product that is mainly present in grapes and citrus, may contribute to cancer prevention. It has many advantages compared to traditional chemotherapeutic drugs, such as low toxicity. To determine whether naringenin can also inhibit metastases, a breast cancer resection model that mimics clinical situations was established. We found that orally administered naringenin significantly decreased the number of metastatic tumor cells in the lung and extended the life span of tumor resected mice. Flow cytometry analysis revealed that T cells displayed enhanced antitumor activity in naringenin treated mice, with an increased proportion of IFN-γ and IL-2 expressing T cells. In vitro studies further demonstrated that relief of immunosuppression caused by regulatory T cells might be the fundamental mechanism of metastasis inhibition by naringenin. These results indicate that orally administered naringenin can inhibit the outgrowth of metastases after surgery via regulating host immunity. Thus, naringenin can be an ideal surgical adjuvant therapy for breast cancer patients.展开更多
T he effect of the anti-infl ammatory fl avonoid chrysin on osteogenesis was determined in preosteoblast MC3T3-E1 cells.Results demonstrated that chrysin could induce osteogenic differentiation in the absence of other...T he effect of the anti-infl ammatory fl avonoid chrysin on osteogenesis was determined in preosteoblast MC3T3-E1 cells.Results demonstrated that chrysin could induce osteogenic differentiation in the absence of other osteo-genic agents.Chrysin treatment promoted the expres-sion of transcription factors(Runx2 and Osx)and bone formation marker genes(Col1A1,OCN,and OPN)as well as enhanced the formation of mineralized nodules.During osteogenic differentiation,chrysin preferentially activated ERK1/2,but not JNK nor the p38 MAPKs.Further experi-ments with inhibitors revealed the co-treatment of U0126,PD98059,or ICI182780(a general ER antagonist)with chrysin effectively abrogated the chrysin-induced osteo-genesis and ERK1/2 activation.Thus,the effect of chrysin on osteogenesis is ERK1/2-dependent and involves ER.Therefore,chrysin has the signifi cant potential to enhance osteogenesis for osteoporosis prevention and treatment.展开更多
Previous studies highlighted the significance of optimizing the cutting blade for crop harvesting and size reduction.This study investigated the effect of blade sliding cutting angle and stem level on cutting energy o...Previous studies highlighted the significance of optimizing the cutting blade for crop harvesting and size reduction.This study investigated the effect of blade sliding cutting angle and stem level on cutting energy of single rice stem using a cutting apparatus that combined with texture analyzer.The cutting energy was determined for four blade angles.The results showed that the average cutting energy was the highest for cutting stem upper level and the lowest for cutting stem lower level.It was found that the peak cutting force per unit stem area decreased with blade sliding cutting angle increased.However,the least average cutting energy was 9.12 J/mm^(2) of 45°sliding angle when cutting without counter support blade and 32.3%less than that of 60°sliding angle.When cutting with counter support blade,the cutting energy per unit stem area varied from 6.57 to 12.54 J/mm 2 as the sliding angle varied from 0°to 60°,whereas the peak cutting force per unit stem area varied from 2.46 to 0.98 N/mm 2.It was concluded that the optimal sliding cutting angle was 45°without support blade and 30°with support blade,respectively.The experiments on rice stems in this study indicated that optimization of sliding cutting angle and stem level have a significant effect on cutting energy savings.Also this study emphasized the need to further investigate the effect of the case of more moisture content and cutting speed on the cutting energy to help in selection of optimum cutting speed and harvesting time.展开更多
In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based...In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based on particle swarm optimization(PSO)algorithm was proposed in this paper.The wheat centralized seed feeding device was taken as the research object,and the experimental factors were cone angle of type hole,working speed and seed filling gap.The working process of wheat centralized seed feeding device was simulated by discrete element method(DEM).The average seed number of type hole,the variation coefficient of the average seed number of type hole,and the maximum tangential force between seed and seed feeding mechanism were selected as the evaluation indexes.Through the variance analysis of the evaluation indexes by the experimental factors,the optimization objective function was constructed.Using PSO algorithm,the multi-objective optimization was carried out for the wheat centralized seed feeding device.The optimization results show that the best structural combination parameters of the wheat centralized seed feeding device are the hole cone angle of 31.6°and the seed filling gap of 4.6 mm.The validity of the method was verified by simulation and field test.The results show that the PSO algorithm multi-objective optimization method proposed in this paper can provide a reference for the structural improvement and optimal design of the centralized seed feeding device.展开更多
Periodic surface structures were fabricated by irradiating lithium niobate(LN) crystals with femtosecond laser pulses at sample temperatures ranging from 28℃ to 800℃. Carrier density and conductivity of the samples ...Periodic surface structures were fabricated by irradiating lithium niobate(LN) crystals with femtosecond laser pulses at sample temperatures ranging from 28℃ to 800℃. Carrier density and conductivity of the samples were increased via heating LN, which inhibited coulomb explosion to obtain a uniform periodic surface structure. The periodic surface structures cover an area of 8 mm × 8 mm and have an average spacing of 174 5 nm.Meanwhile, the absorption of the processed sample is about 70% in the spectral range of 400–1000 nm, which is one order of magnitude higher than that of pure LN. Fabrication of periodic surface structures on heating LN with femtosecond laser pulses provides a possibility to generate nanogratings or nanostructures on wide-bandgap transparent crystals.展开更多
Straw returning into field is a direct and effective measure to reduce the straw burning and improve the soil organic matter content.Straw returning directly to field needs higher performance machines,especially under...Straw returning into field is a direct and effective measure to reduce the straw burning and improve the soil organic matter content.Straw returning directly to field needs higher performance machines,especially under the condition of large amount of straw in the field is more difficult.Therefore,the model of conservation tillage by combination of subsoiling and straw returning was studied.Experiments on combined tillage machine for effect of subsoiling on working quality and total power consumption for high stubble straw returning were carried out.The high stubble rape field was used as the test field;forward speed and PTO speed of tractor were taken as the test factors.Straw coverage rate and straw proportion of the lower half burying layer were taken as the test indexes of the working quality.Subsoiling and rotary burying(SRB)returning operation was used as experimental group and direct rotary burying(DRB)returning operation was the control group.The results showed that under different working conditions,the mean value of straw coverage rate of SRB was 93.0%,straw proportion of the lower half burying layer was 52.8%,these values were better than DRB.The straw proportion of the lower half burying layer of SRB compared with DRB increased by 10.5%.Two factors all had a significant effect on it under the SRB and DRB conditions.Subsoiling could significantly reduce the PTO torque.Under low speed,the total power consumption of SRB was slightly smaller,while under high speed,the total power consumption of DRB was slightly smaller.Under the SRB and DRB conditions,two factors both had a significant effect on total power consumption.The optimal working combination(working quality as the primary index)was 1.5 km/h of forward speed and 720 r/min of PTO speed.Under this condition,the straw coverage rate was 94.1%,the straw proportion of the lower half burying layer was 59.0%,and the total power consumption was 35.62 kW.The research confirmed that subsoiling is beneficial to the working quality and total power consumption of high stubble straw returning machine.It could meet the working requirements,and provide a reference for optimizing straw returning machine and improving working quality.展开更多
In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding(PISG)technique.The depth-dependent deformation parameters(strain...In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding(PISG)technique.The depth-dependent deformation parameters(strain,strain rate and strain gradient)were evaluated and the microstructures were systematically characterized.Microstructural evolution from millimeter-to nano-scale was explored,with special attention paid to the localized deformation.Microstructural evolution begins with the formation of planar dislocation arrays and the twin-matrix lamellae,which is followed by the localized deformation characterized by the initiation and the development of shear bands.A twinning-dominated process that was supplemented with dislocation slip-dominated one governed the microstructural evolution inside shear bands.The twin-matrix lamellae transform into extended/lamellar structure and finally the nanosized grains.Austenitic grains were substantially refined and martensitic transformation was effectively suppressed,of which the underlying mechanisms were analyzed.展开更多
In the present investigation, a pipe inner-surface grinding（PISG） technique was developed to fabricate nanostructure in the inner-surface of an austenitic 304 stainless steel pipe. PISG was performed by high speed s...In the present investigation, a pipe inner-surface grinding（PISG） technique was developed to fabricate nanostructure in the inner-surface of an austenitic 304 stainless steel pipe. PISG was performed by high speed shearing with hard sphere tips, leading to gradient distribution of strain, strain rate and strain gradient along depth. Nano-austenite with an average boundary spacing of 20 nm was generated, followed by deformation microstructure characterized by shear bands, multi-and uni-directional twins and planar dislocation arrays. Deformation induced grain refinement of austenitic 304 stainless steel with low stacking fault energy（SFE） covering 4–5 order＇s magnitude of length scales toward nanometer regime was unified.展开更多
基金supported by the National Natural Science Foundation of China(22178190).
文摘In the petrochemical industry process, the relative volatility between the components to be separated is close to one or the azeotrope that systems are difficult to separate. Liquid-liquid extraction is a common and effective separation method, and selecting an extraction agent is the key to extraction technology research. In this paper, a design method of extractants based on elements and chemical bonds was proposed. A knowledge-based molecular design method was adopted to pre-select elements and chemical bond groups. The molecules were automatically synthesized according to specific combination rules to avoid the problem of “combination explosion” of molecules. The target properties of the extractant were set, and the extractant meeting the requirements was selected by predicting the correlation physical properties of the generated molecules. Based on the separation performance of the extractant in liquid-liquid extraction and the relative importance of each index, the fuzzy comprehensive evaluation membership function was established, the analytic hierarchy process determined the mass ratio of each index, and the consistency test results were passed. The results of case study based on quantum chemical analysis demonstrated that effective determination of extractants for the analysis of benzene-cyclohexane systems. The results unanimously prove that the method has important theoretical significance and application value.
基金The National Natural Science Foundation of China under contract Nos 42122046,42076202,U1811464 and 4210060098the Project Supported by Laoshan Laboratory under contract No.LSKJ202201500the Project Supported by Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract No.SML2021SP102.
文摘The international Argo program,a global observational array of nearly 4000 autonomous profiling floats initiated in the late 1990s,which measures the water temperature and salinity of the upper 2000 m of the global ocean,has revolutionized oceanography.It has been recognized one of the most successful ocean observation systems in the world.Today,the proposed decade action“OneArgo”for building an integrated global,full-depth,and multidisciplinary ocean observing array for beyond 2020 has been endorsed.In the past two decades since 2002,with more than 500 Argo deployments and 80 operational floats currently,China has become an important partner of the Argo program.Two DACs have been established to process the data reported from all Chinese floats and deliver these data to the GDACs in real time,adhering to the unified quality control procedures proposed by the Argo Data Management Team.Several Argo products have been developed and released,allowing accurate estimations of global ocean warming,sea level change and the hydrological cycle,at interannual to decadal scales.In addition,Deep and BGC-Argo floats have been deployed,and time series observations from these floats have proven to be extremely useful,particularly in the analysis of synoptic-scale to decadal-scale dynamics.The future aim of China Argo is to build and maintain a regional Argo fleet comprising approximately 400 floats in the northwestern Pacific,South China Sea,and Indian Ocean,accounting for 9%of the global fleet,in addition to maintaining 300 Deep Argo floats in the global ocean(25%of the global Deep Argo fleet).A regional BGC-Argo array in the western Pacific also needs to be established and maintained.
基金supported by the Natural Science Basic Research Program of Shaanxi (No. 2023-JC-YB-065)the Fund of State Key Laboratory of IPOC(BUPT)(No. IPOC2019A013)+2 种基金the Natural Science Foundation of Shaanxi Province (No. 2021JM-371)the Open-Foundation of Key Laboratory of Laser Device Technology,China North Industries Group Corporation Limited (No. KLLDT202103)the Project funded by China Postdoctoral Science Foundation(No. 2022M720516)。
文摘The design of efficient and low-cost multifunctional electrocatalysts for hydrogen evolution reaction(HER), oxygen evolution reaction(OER) and oxygen reduction reaction(ORR) is critical for the development of clean energy. Two-dimensional(2D) carbon-based nano-materials are becoming more and more popular in heterogeneous catalysis due to their cost-effective and multi-scale tunability as single-atom catalysis(SACs) substrates. In this paper, by using first-principles calculation, we designed and demonstrated a novel macropore T-carbon [110](TC) monolayer as 2D electrocatalyst substrate for HER/OER/ORR, and the synergistic modification of the transition metal and nonmetal atoms(TM-X) were investigated to enhance the multifunctional electrocatalytic performance. We screened out the Co embedded in N-doped TC(Co3@N-TC) from 30 TM@X-TC monolayers as a trifunctional electrocatalysts, which exhibits superior performance for HER/ORR/OER on both thermodynamic and kinetic scales, and with excellent thermal and electrochemical stability. Then, the TC monolayer is naturally macropore with a diameter of 5.36 A and exhibits excellent adsorption capacity for the intermediates and products of the redox reactions. Moreover, we revealed the origin of the electrocatalytic activity using the crystal orbital Hamilton population(COHP) and the molecular orbitals(MOs). The d orbital of Co3@N-TC is significantly hybridized with the p orbital of the intermediates, so that the lone electrons initially occupied in the antibonding state pair up and occupy the downward bonding state, allowing *OH to be appropriately adsorbed onto the TC monolayer. This work not only demonstrates that the TM@X-TC monolayer is a superior synergistic trifunctional electrocatalyst, but also reveals a macropore monolayer material with potential applications in electrocatalysis.
基金This research was supported by Grants from National Training Programs of Innovation and Entrepreneurship for Undergraduates(Grant No.201810504048).
文摘Rose is sensitive to high temperature which will make the rose go into a semi-dormancy state.Grafting is an excellent way to enhance rose heat tolerance.Here,heat-tolerant Rosa multiflora‘Huanong Wuci 1'(W)and heat-sensitive Rosa chinensis‘Old Blush’(X)were selected as experimental materials.The RNA-seq technique was used to investigate the transcriptomes of self-root grafting line(XX0),heterogeneous grafting line(XW0),self-root grafting line under 6 h heat stress(XX6),and heterogeneous grafting line under 6 h heat stress(XW6).Under high temperature stress,multiple signaling pathways were activated,moreover,a large number of transcription factors and functional genes were induced,especially the HSFs and HSPs with remarkably upregulated expression levels.The GO analysis showed that the differences in the expressions of the genes related to fatty acids and carbohydrates were observed between self-root grafting line and heterogeneous grafting line.In addition,14 P450s were differentially expressed,and one lectin gene was up-regulated in XW0 vs XW6,but down-regulated in XX0 vs XX6.Considering physiological and biochemical traits such as relative electrolyte leakage,SOD activity,proline,and total soluble sugars,DEGs involved in these processes may be key factors to resist high temperature.The present study provides an insight into the complex mechanism underlying grafting in response to heat stress.Our results indicate that grafting is an effective way to improve rose heat resistance.
基金supported by grants from the National Key R&D Program of China (Grant No. 2018YFD1000100)National Natural Science Foundation of China (Grant No. 31972378)Agricultural Variety Improvement Project of Shandong Province (Grant No. 2019LZGC007)
文摘Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated 9(CRISPR/Cas9)system has recently become one popular technology due to its efficiency,precision,and simplicity compared with other genome editing tools such as Zinc Finger Nucleases(ZFNs)and Transcription Activator Like Effector Nucleases(TALENs).Horticultural crops provide energy and health-keeping nutrients to humankind.Genome-editing technology has become widely adopted in horticultural breeding with the increasing demand for high yield and better-quality horticultural crops.Here,we describe the CRISPR/Cas9 system construction,its optimization,including sgRNA promoter,sgRNA design,Cas9 protein promoter,SpCas9 variants and orthologs,and vector delivery methods.We also summarized the application of this technology in horticultural plants for stress responses enhancement,fruit quality improvement,and cultivation traits modification.This detailed review was compiled to help establish comprehensive understanding of the CRISPR/Cas9 systems and provide a reference for further developing this technology to manipulate horticultural plant traits effectively.
基金Supported by Shandong Provincial Natural Science Foundation of China(ZR2012CQ012)Shandong Provincial Technical Innovation Grant of China(201220916006)
文摘Pseudorabies virus glycoprotein E （PRV gE） has been recognized as a suitable diagnostic antigen for pseudorabies. In order to produce gE antigen in large quantities and at low cost, a gene fragment encoding PRV gE core epitopes was expressed in E. coli BL21 expression system. SDS-PAGE and Western Blotting revealed that the expression product in culture supematant of E. coli BL21 was a recombinant protein, approximately 51.8 Kd. At 5 h post-induction, protein concentration assay showed that the expression product amounted to 1.65 mg/ml, accounting for 24. 17% of total proteins in the culture supematant. An indirect PRV gE-ELISA was established by using the recombinant expression product as a coating antigen. Cross-reactivity assay showed that this antigen was PRV specific. In addition, the assay was consistently reproducible. Comparison of detection results of 240 serum samples between PRV gE-ELISA and a commercially available PRV diagnostic kit showed that there was no significant difference between these two methods （P 〉 0.05 ）.
基金the National Natural Science Foundation of China, No. 81041019the National High-Technology Research and Development Program of China (863 Program), No.2006AA02Z436
文摘This study sought to elucidate the genetic correlation of cerebral venous sinus thrombosis caused by a hereditary antithrombin deficiency in a Chinese family, at the genetic and protein levels. A nonsense mutation from C to T on locus 6431 in exon 3B of the antithrombin gene was observed, leading to an arginine （CGA） to stop codon （TGA） change in the protein. This is the first report of this mutation in China. Ineffective heparin therapy in the propositus patient is associated with a lack of heparin binding sites after antithrombin gene mutation. Characteristic low intracranial pressure in the acute phase might be specific to this patient with cerebral venous sinus thrombosis.
基金The National Natural Science Foundation of China under contract No.4210060098the Foundation of Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources under contract No.A1-2006-21-200201.
文摘The current lack of high-precision information on subsurface seawater is a constraint in fishery research.Based on Argo temperature and salinity profiles,this study applied the gradient-dependent optimal interpolation to reconstruct daily subsurface oceanic environmental information according to fishery dates and locations.The relationship between subsurface information and matching yellowfin tuna(YFT)in the western and central Pacific Ocean(WCPO)was examined using catch data from January 1,2008 to August 31,2017.The seawater temperature and salinity results showed differences of less than±0.5°C and±0.01 compared with the truth observations respectively.Statistical analysis revealed that the most suitable temperature for YFT fishery was 28–29°C at the near-surface.The most suitable salinity range for YFT fishery was 34.5–36.0 at depths shallower than 300 m.The suitable upper and lower bounds on the depths of the thermocline were 90–100 m and 300–350 m,respectively.The thermocline characteristics were prominent,with a mean temperature gradient exceeding 0.08°C/m.These results indicate that the profiles constructed by gradient-dependent optimal interpolation were more accurate than those of the nearest profiles adopted.
基金This research was funded by the National Nature Foundation nos.4210060098,the Argo buoy project under Grant D-8006-21-0082the Foundation of Key Laboratory of ocean fishery development under Grant A1-2006-21-200201the Foundation of fishery resources Comprehensive Scientific Surveys in the Northwest Pacific D-8021-21-0109-01.
文摘Argo has become an important constituent of the global ocean observation system.However,due to the lack of sea surface measurements from most Argo profiles,the application of Argo data is still limited.In this study,a thermocline model was constructed based on three key thermocline parameters,i.e,thermocline upper depth,the thermocline bottom depth,and thermocline temperature gradient.Following the model,we estimated the sea surface temperature of Argo profiles by providing the relationship between sea surface and subsurface temperature.We tested the effectiveness of our proposed model using statistical analysis and by comparing the sea surface temperature with the results obtained from traditional methods and in situ observations in the Pacific Ocean.The root mean square errors of results obtained from thermocline model were found to be significantly reduced compared to the extrapolation results and satellite retrieved temperature results.The correlation coefficient between the estimation result and in situ observation was 0.967.Argo surface temperature,estimated by the thermocline model,has been theoretically proved to be reliable.Thus,our model generates theoretically feasible data present the mesoscale phenomenon in more detail.Overall,this study compensates for the lack surface observation of Argo,and provides a new tool to establish complete Argo data sets.
基金This research was funded by the Science and Technology Fund of Guizhou Province,Grant No.(2016)7125the National Natural Science Foundation of China,Grant No.81660710the Natural Science Research Fund of Guizhou Education Department,Grant No.(2017)042.
文摘In our previous study,silver nanoparticles were prepared using AgNO_(3) and carboxymethyl chitosan(CMCS)which is commercially available with solar irradiation.In this study,the efficacy and safety of silver nanoparticles prepared by this method were evaluated for healing wounds in rats with diabetes.We also attempted to determine the underlying mechanism and influencing factors of the silver nanomaterial preparation method.Compared with growth factors,silver nanoparticles exhibit better healing effects for rats with diabetes.No remnant silver ions were detected in the major organs of these rats after the application of silver nanoparticles.Silver nanoparticles prepared using CMCS are less toxic than those prepared from the conventional method,promote the proliferation of skin fibroblasts,and are promising as a topical medication for infected wounds.An obvious breakage process of the particles is observed during the growth of nanocrystalline silver in CMCS.In this study,we also attempted to determine whether this method is suitable for synthesizing silver nanoparticles using N-trimethyl chitosan chloride and sodium alginate were used in this particular experiment.The characteristic UV-vis absorbance peak of silver nanoparticles was found only in the reaction mixture containing N-trimethyl chitosan chloride.Our study demonstrates that free radicals are the key factor in this silver nanoparticle preparation method.
基金supported by The State Key Development Plan Project(Grant No.2011CB707705).
文摘Metastasis is the main cause of death in cancer patients. To improve the outcomes of patients undergoing a surgery, new adjuvant therapies that can effectively inhibit metastases have to be developed. Studies have shown that flavonoid naringenin, a natural product that is mainly present in grapes and citrus, may contribute to cancer prevention. It has many advantages compared to traditional chemotherapeutic drugs, such as low toxicity. To determine whether naringenin can also inhibit metastases, a breast cancer resection model that mimics clinical situations was established. We found that orally administered naringenin significantly decreased the number of metastatic tumor cells in the lung and extended the life span of tumor resected mice. Flow cytometry analysis revealed that T cells displayed enhanced antitumor activity in naringenin treated mice, with an increased proportion of IFN-γ and IL-2 expressing T cells. In vitro studies further demonstrated that relief of immunosuppression caused by regulatory T cells might be the fundamental mechanism of metastasis inhibition by naringenin. These results indicate that orally administered naringenin can inhibit the outgrowth of metastases after surgery via regulating host immunity. Thus, naringenin can be an ideal surgical adjuvant therapy for breast cancer patients.
文摘T he effect of the anti-infl ammatory fl avonoid chrysin on osteogenesis was determined in preosteoblast MC3T3-E1 cells.Results demonstrated that chrysin could induce osteogenic differentiation in the absence of other osteo-genic agents.Chrysin treatment promoted the expres-sion of transcription factors(Runx2 and Osx)and bone formation marker genes(Col1A1,OCN,and OPN)as well as enhanced the formation of mineralized nodules.During osteogenic differentiation,chrysin preferentially activated ERK1/2,but not JNK nor the p38 MAPKs.Further experi-ments with inhibitors revealed the co-treatment of U0126,PD98059,or ICI182780(a general ER antagonist)with chrysin effectively abrogated the chrysin-induced osteo-genesis and ERK1/2 activation.Thus,the effect of chrysin on osteogenesis is ERK1/2-dependent and involves ER.Therefore,chrysin has the signifi cant potential to enhance osteogenesis for osteoporosis prevention and treatment.
基金This study was funded by the Chinese Government through the Anhui Agricultural University within a program titled“The National Key Research and Development Program of China(No.2017YFD0301303)”the China’s Ministry of Agriculture through the China Agricultural University with a program titled“China’s Ministry of Agriculture,Agricultural Public Welfare Industry Special Project(No.201503136)”.
文摘Previous studies highlighted the significance of optimizing the cutting blade for crop harvesting and size reduction.This study investigated the effect of blade sliding cutting angle and stem level on cutting energy of single rice stem using a cutting apparatus that combined with texture analyzer.The cutting energy was determined for four blade angles.The results showed that the average cutting energy was the highest for cutting stem upper level and the lowest for cutting stem lower level.It was found that the peak cutting force per unit stem area decreased with blade sliding cutting angle increased.However,the least average cutting energy was 9.12 J/mm^(2) of 45°sliding angle when cutting without counter support blade and 32.3%less than that of 60°sliding angle.When cutting with counter support blade,the cutting energy per unit stem area varied from 6.57 to 12.54 J/mm 2 as the sliding angle varied from 0°to 60°,whereas the peak cutting force per unit stem area varied from 2.46 to 0.98 N/mm 2.It was concluded that the optimal sliding cutting angle was 45°without support blade and 30°with support blade,respectively.The experiments on rice stems in this study indicated that optimization of sliding cutting angle and stem level have a significant effect on cutting energy savings.Also this study emphasized the need to further investigate the effect of the case of more moisture content and cutting speed on the cutting energy to help in selection of optimum cutting speed and harvesting time.
基金The authors acknowledge that this work was financially supported by Collaborative Innovation Project of Anhui Colleges and Universities(GXXT-2019-036)Nature Science Fund Project of Anhui province(2008085QE217)Natural Science Fund Project of Anhui Agricultural University(2019zd09).
文摘In order to solve the problem of interaction between multiple evaluation indexes of seed metering performance under multiple factors of centralized seed feeding device,a multi-objective optimization of structure based on particle swarm optimization(PSO)algorithm was proposed in this paper.The wheat centralized seed feeding device was taken as the research object,and the experimental factors were cone angle of type hole,working speed and seed filling gap.The working process of wheat centralized seed feeding device was simulated by discrete element method(DEM).The average seed number of type hole,the variation coefficient of the average seed number of type hole,and the maximum tangential force between seed and seed feeding mechanism were selected as the evaluation indexes.Through the variance analysis of the evaluation indexes by the experimental factors,the optimization objective function was constructed.Using PSO algorithm,the multi-objective optimization was carried out for the wheat centralized seed feeding device.The optimization results show that the best structural combination parameters of the wheat centralized seed feeding device are the hole cone angle of 31.6°and the seed filling gap of 4.6 mm.The validity of the method was verified by simulation and field test.The results show that the PSO algorithm multi-objective optimization method proposed in this paper can provide a reference for the structural improvement and optimal design of the centralized seed feeding device.
基金National Natural Science Foundation of China(NSFC)(11574158,61378018)111 Project(B07013)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT_13R29)Fundamental Research Funds for the Central Universities
文摘Periodic surface structures were fabricated by irradiating lithium niobate(LN) crystals with femtosecond laser pulses at sample temperatures ranging from 28℃ to 800℃. Carrier density and conductivity of the samples were increased via heating LN, which inhibited coulomb explosion to obtain a uniform periodic surface structure. The periodic surface structures cover an area of 8 mm × 8 mm and have an average spacing of 174 5 nm.Meanwhile, the absorption of the processed sample is about 70% in the spectral range of 400–1000 nm, which is one order of magnitude higher than that of pure LN. Fabrication of periodic surface structures on heating LN with femtosecond laser pulses provides a possibility to generate nanogratings or nanostructures on wide-bandgap transparent crystals.
基金The authors acknowledge that this work was supported by the Special Fund for Agro-scientific Research in the Public Interest(No.201503136)the National Key Technology R&D Program(No.2017YFD0301300).
文摘Straw returning into field is a direct and effective measure to reduce the straw burning and improve the soil organic matter content.Straw returning directly to field needs higher performance machines,especially under the condition of large amount of straw in the field is more difficult.Therefore,the model of conservation tillage by combination of subsoiling and straw returning was studied.Experiments on combined tillage machine for effect of subsoiling on working quality and total power consumption for high stubble straw returning were carried out.The high stubble rape field was used as the test field;forward speed and PTO speed of tractor were taken as the test factors.Straw coverage rate and straw proportion of the lower half burying layer were taken as the test indexes of the working quality.Subsoiling and rotary burying(SRB)returning operation was used as experimental group and direct rotary burying(DRB)returning operation was the control group.The results showed that under different working conditions,the mean value of straw coverage rate of SRB was 93.0%,straw proportion of the lower half burying layer was 52.8%,these values were better than DRB.The straw proportion of the lower half burying layer of SRB compared with DRB increased by 10.5%.Two factors all had a significant effect on it under the SRB and DRB conditions.Subsoiling could significantly reduce the PTO torque.Under low speed,the total power consumption of SRB was slightly smaller,while under high speed,the total power consumption of DRB was slightly smaller.Under the SRB and DRB conditions,two factors both had a significant effect on total power consumption.The optimal working combination(working quality as the primary index)was 1.5 km/h of forward speed and 720 r/min of PTO speed.Under this condition,the straw coverage rate was 94.1%,the straw proportion of the lower half burying layer was 59.0%,and the total power consumption was 35.62 kW.The research confirmed that subsoiling is beneficial to the working quality and total power consumption of high stubble straw returning machine.It could meet the working requirements,and provide a reference for optimizing straw returning machine and improving working quality.
基金the financial support of the Hundred Outstanding Creative Talents Projects in Hebei University,Chinathe Project Program of Heavy Machinery Collaborative Innovation Center,Chinathe National Natural Foundation of Hebei Province,China (Grant No. E2018203312)
文摘In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding(PISG)technique.The depth-dependent deformation parameters(strain,strain rate and strain gradient)were evaluated and the microstructures were systematically characterized.Microstructural evolution from millimeter-to nano-scale was explored,with special attention paid to the localized deformation.Microstructural evolution begins with the formation of planar dislocation arrays and the twin-matrix lamellae,which is followed by the localized deformation characterized by the initiation and the development of shear bands.A twinning-dominated process that was supplemented with dislocation slip-dominated one governed the microstructural evolution inside shear bands.The twin-matrix lamellae transform into extended/lamellar structure and finally the nanosized grains.Austenitic grains were substantially refined and martensitic transformation was effectively suppressed,of which the underlying mechanisms were analyzed.
基金supported financially by the Hundred Outstanding Creative Talents Projects in University of Hebei ProvinceChina, the Project Program of Heavy Machinery Collaborative Innovation Center+1 种基金the Natural Science Foundation of Hebei Province, China (No. E2018203312)the Postdoctoral Science Foundation of Hebei Province, China
文摘In the present investigation, a pipe inner-surface grinding（PISG） technique was developed to fabricate nanostructure in the inner-surface of an austenitic 304 stainless steel pipe. PISG was performed by high speed shearing with hard sphere tips, leading to gradient distribution of strain, strain rate and strain gradient along depth. Nano-austenite with an average boundary spacing of 20 nm was generated, followed by deformation microstructure characterized by shear bands, multi-and uni-directional twins and planar dislocation arrays. Deformation induced grain refinement of austenitic 304 stainless steel with low stacking fault energy（SFE） covering 4–5 order＇s magnitude of length scales toward nanometer regime was unified.
