Building well-developed ion-conductive highways is highly desirable for anion exchange membranes(AEMs).Grafting side chain is a highly effective approach for constructing a well-defined phaseseparated morphological st...Building well-developed ion-conductive highways is highly desirable for anion exchange membranes(AEMs).Grafting side chain is a highly effective approach for constructing a well-defined phaseseparated morphological structure and forming unblocked ion pathways in AEMs for fast ion transport.Fluorination of side chains can further enhance phase separation due to the superhydrophobic nature of fluorine groups.However,their electronic effect on the alkaline stability of side chains and membranes is rarely reported.Here,fluorine-containing and fluorine-free side chains are introduced into the polyaromatic backbone in proper configuration to investigate the impact of the fluorine terminal group on the stability of the side chains and membrane properties.The poly(binaphthyl-co-p-terphenyl piperidinium)AEM(QBNp TP)has the highest molecular weight and most dimensional stability due to its favorable backbone arrangement among ortho-and meta-terphenyl based AEMs.Importantly,by introducing both a fluorinated piperidinium side chain and a hexane chain into the p-terphenyl-based backbone,the prepared AEM(QBNp TP-QFC)presents an enhanced conductivity(150.6 m S cm^(-1))and a constrained swelling at 80℃.The electronic effect of fluorinated side chains is contemplated by experiments and simulations.The results demonstrate that the presence of strong electro-withdrawing fluorine groups weakens the electronic cloud of adjacent C atoms,increasing OH^(-)attack on the C atom and improving the stability of piperidinium cations.Hence QBNp TP-QFC possesses a robust alkaline stability at 80℃(95.3%conductivity retention after testing in 2 M Na OH for 2160 h).An excellent peak power density of 1.44 W cm^(-2)and a remarkable durability at 80℃(4.5%voltage loss after 100 h)can be observed.展开更多
Bismuth (Bi) has indeed inspired great interests in lithium-ion batteries (LIBs) due to the high capacity,but was still limited by the low electrical conductivity and large volume variation.Herein,a composite material...Bismuth (Bi) has indeed inspired great interests in lithium-ion batteries (LIBs) due to the high capacity,but was still limited by the low electrical conductivity and large volume variation.Herein,a composite material based on Bi nanoparticles in situ encapsulated by carbon film (Bi@CF) is prepared successfully through a facile metal–organic framework (MOF)-engaged approach.As anode materials for LIBs,the Bi@CF composites achieved high reversible capacities of 705 and 538 mAh g^(-1)at 0.2 and 0.5 A g^(-1) after200 cycles,and long cycling performance with a stable capacity of 306 mAh g^(-1)at 1.0 A g^(-1) even after 900 cycles.In situ X-ray diffraction (XRD) measurements clearly revealed the conversion between Bi and Li_(3)Bi during the alloying/dealloying process,confirming the good electrochemical reversibility of Bi@CF for Li-storage.The reaction kinetics of this Bi@CF composite was further studied by galvanostatic intermittent titration technique (GITT).This work may provide an inspiration for the elaborate design and facile preparation of alloy-type anode materials for high-performance rechargeable batteries.展开更多
The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of mi...The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.展开更多
Rose(Rosa chinensis),which is an economically valuable floral species worldwide,has three types,namely once-flowering(OF),occasional or re-blooming(OR),and recurrent or continuous flowering(CF).However,the mechanism u...Rose(Rosa chinensis),which is an economically valuable floral species worldwide,has three types,namely once-flowering(OF),occasional or re-blooming(OR),and recurrent or continuous flowering(CF).However,the mechanism underlying the effect of the age pathway on the duration of the CF or OF juvenile phase is largely unknown.In this study,we observed that the RcSPL1 transcript levels were substantially upregulated during the floral development period in CF and OF plants.Additionally,accumulation of RcSPL1 protein was controlled by rch-miR156.The ectopic expression of RcSPL1 in Arabidopsis thaliana accelerated the vegetative phase transition and flowering.Furthermore,the transient overexpression of RcSPL1 in rose plants accelerated flowering,whereas silencing of RcSPL1 had the opposite phenotype.Accordingly,the transcription levels of floral meristem identity genes(APETALA1,FRUITFULL,and LEAFY)were significantly affected by the changes in RcSPL1 expression.RcTAF15b protein,which is an autonomous pathway protein,was revealed to interact with RcSPL1.The silencing and overexpression of RcTAF15b in rose plants led to delayed and accelerated flowering,respectively.Collectively,the study findings imply that RcSPL1–RcTAF15b modulates the flowering time of rose plants.展开更多
The oxygen evolution reaction(OER) is the cornerstone for many important energy conversion devices, including metal–air battery and water splitting.Herein, an optimized NiFe-based metal–organic framework is develope...The oxygen evolution reaction(OER) is the cornerstone for many important energy conversion devices, including metal–air battery and water splitting.Herein, an optimized NiFe-based metal–organic framework is developed as highly efficient active material for OER. It just needs a low overpotential of 0.31 V to deliver a current density of 10 mA cm-2 with a favorable Tafel slope of 43.7 mV dec-1 in 0.1 M KOH electrolyte for the as-prepared Ni0.75Fe0.25 BDC, which is superior to RuO2. This efficient catalytic performance is due to the introduction of Fe in Ni-based MOFs could benefit the kinetics and charge transfer efficiency, resulting in the optimal activity toward OER. Besides, the obtained active material demonstrates good stability, suggesting the great potential value in sustainable electrochemical energy storage and conversion devices.展开更多
In order to further understand the effects of drought stress on hydraulic characteristics and the relationship between hydraulic conductivity and aquaporins or water channels of root systems of three wolfberry cultiva...In order to further understand the effects of drought stress on hydraulic characteristics and the relationship between hydraulic conductivity and aquaporins or water channels of root systems of three wolfberry cultivars(Lycium chinense Mill.),hydraulic conductivity of 2-yearold pot-grown seedlings was measured under drought stress,rewatering,and treatment with exogenous mercuric chloride andβ-mercaptoethanol.Under moderate and severe drought stress levels,the most significant decrease of hydraulic conductivity was 37.3%and 24.0%,respectively,in the‘Ningqi 5’cultivar compared with the nonstressed control.After rewatering,the rate of recovery in specific conductivity was most rapid in the‘Mengqi 1’cultivar,at 0.058 and 0.072 kg MPa^-1 m^-2 s^-1 h^-1 under moderate and severe drought stress levels,respectively.The‘Mengqi 1’cultivar had the highest recovery degree of hydraulic conductivity under two concentrations ofβ-ME(500 or 1000 lmol L^-1),reaching 82.4%and 88.5%,respectively,of the initial conductivity.The adaptive capacity of hydraulic conductivity in the‘Ningqi 5’cultivar was weaker than in the‘Ningqi 1’and‘Mengqi 1’cultivars under drought stress.The recovery capacity of hydraulic conductivity in‘Mengqi 1’cultivar was stronger than the‘Ningqi 1’and‘Ningqi 5’cultivars after rewatering.Aquaporins of the‘Ningqi 1’cultivar root systems had the highest binding affinity with mercuric chloride,which was the most likely cause in the decrease in hydraulic conductivity,whereas aquaporins of‘Mengqi 1’root systems had the weakest binding affinity.The inhibitory effect of mercuric chloride was readily eliminated byβ-mercaptoethanol in the‘Mengqi 1’cultivar.The hydraulic characteristics of this cultivar were more sensitive to drought,mercuric chloride andβ-mercaptoethanol than the other cultivars.展开更多
Studying the genetic basis and regulatory mechanism of chrysanthemum lateral bud outgrowth is of great significance for reduction the production cost of cut chrysanthemum.To clarify the molecular basis of lateral bud ...Studying the genetic basis and regulatory mechanism of chrysanthemum lateral bud outgrowth is of great significance for reduction the production cost of cut chrysanthemum.To clarify the molecular basis of lateral bud elongation after removal of apical dominance in chrysanthemum,label-free quantification analysis was used to analyze the proteome changes after apical bud removal.Quantitative real-time PCR(qPCR)was used to analyze the changes in the expression of three plant hormone-related genes.A total of 440 differentially expressed proteins were successfully identified at three time points during the lateral bud elongation.The number of differentially expressed proteins in the three stages(24 h/0 h,48 h/0 h,48 h/24 h)were 219,332,and 97,respectively.The difference in expressed proteins in the three comparison stages mainly involves RNA processing and modification;translation,ribosomal structure and biogenesis;Posttranslational modification,protein turnover,and chaperones.Path analysis showed that there was various physiological activities in the process of lateral bud dormancy breaking and elongation,which involved energy metabolism,biosynthesis,signal transduction and stress response in the growth process of lateral buds.qPCR indicated that the expression of cytokinin synthesis related gene was significantly increased after the removal of apical dominance,while the expression of strigolactones synthesis related gene experiences a dramatic fall to promote the development of the lateral buds.However,there was a drop before a slight increase in the expression of the auxin synthesis related gene,which was mainly due to the removal of apical dominance that led to the loss of indoleacetic acid in the main stem.However,with formation of the new apical source,indoleacetic acid can be released again.展开更多
Although the selective hydrogenation ofα,β-unsaturated aldehyde to unsaturated alcohol(UOL)is an extremely important transformation,it is still a great challenge to achieve high selectivity to UOL due to thermodynam...Although the selective hydrogenation ofα,β-unsaturated aldehyde to unsaturated alcohol(UOL)is an extremely important transformation,it is still a great challenge to achieve high selectivity to UOL due to thermodynamic favoring of the C=C hydrogenation over the C=O hydrogenation.Herein,we report that iridium nanoclusters(Ir NCs)confined within hollow MIL-101(Fe)expresses satisfied reaction activity(93.9%)and high selectivity(96.2%)for the hydrogenation of cinnamaldehyde(CAL)to cinnamyl alcohol(COL)under 1 bar H;atmosphere and room temperature.The unique hollow structure of MIL-101(Fe)benefits for the fast transport of reactant,ensuring the comparable reaction activity and better recyclability of Ir@MIL-101(Fe)than the counterparts which Ir NCs were on the surface of MIL-101(Fe).Furthermore,The X-ray photoelectron spectroscopy data indicates the electropositive Ir NCs,owing to the electron transfer from Ir to MIL-101(Fe),can interact with oxygen lone pairs,and Fourier transform infrared spectrum shows the Lewis acid sites in MIL-101(Fe)can strongly interact with C=O bond,which contributes to a high selectivity for COL.This work suggests the considerable potential of synergetic effect between hollow MOFs and metal nanoclusters for selective hydrogenation reactions.展开更多
Exploring platinum group metal-free electrocatalysts with superior catalytic performance and favorable durability for oxygen reduction reaction is a remaining bottleneck in process of developing sustainable techniques...Exploring platinum group metal-free electrocatalysts with superior catalytic performance and favorable durability for oxygen reduction reaction is a remaining bottleneck in process of developing sustainable techniques in energy storage and conversion. Herein, a hierarchical porous single atomic Fe electrocatalyst(Fe/Z8-E-C) is rationally designed and synthesized via acid etching, calcination, adsorption of Fe precursor and recalcination processes. This unique electrocatalyst Fe/Z8-E-C shows excellent oxygen reduction performance with a half-wave potential of 0.89 V in 0.1 mol/L KOH, 30 m V superior to that of commercial Pt/C(0.86 V), which is also significantly higher than that of typical Fe-doped ZIF-8 derived carbon nanoparticles(Fe/Z8-C) with a half-wave potential of 0.84 V. Furthermore, Fe/Z8-E-C-based Zn-air battery exhibits greatly enhanced peak power density and specific capacity than those of original Fe/Z8-C,verifying the remarkable performance and practicability of this specially designed hierarchical structure due to its efficient utilization of the active sites and rapid mass transfer. This present work proposes a new method to rationally synthesize single atom electrocatalysts loaded on hierarchical porous frame materials for catalysis and energy conversion.展开更多
Background:We investigated whether periodontal diseases,specifically,periodontitis and gingivitis,could be risk factors of the incidence of intracranial aneurysms(IAs).Methods:We performed a case–control study to com...Background:We investigated whether periodontal diseases,specifically,periodontitis and gingivitis,could be risk factors of the incidence of intracranial aneurysms(IAs).Methods:We performed a case–control study to compare the differences in the periodontal disease parameters of 281 cases that were divided into the IAs group and non-IAs group.All cases underwent complete radiographic examination for IAs and examination for periodontal health.Results:Comparing with those in the non-IAs group,the cases in the IAs group were older(53.95±8.56 vs 47.79±12.33,p<0.001)and had a higher incidence of hypertension(76 vs 34,p=0.006).Univariate logistic regression analysis revealed that age(>50 years)and hypertension were predictive risk factors of aneurysm formation(odds ratio[OR]1.047,95%confidence interval[95%CI]1.022–1.073,p<0.001 and OR 2.047,95%CI 1.232–3.401,p=0.006).In addition,univariate and multivariate logistic regression analyses showed that the parameters of periodontal diseases,including gingival index,plaque index,clinical attachment loss,and alveolar bone loss,were significantly associated with the occurrence of IAs(all p<0.05).For further statistical investigation,the parameters of periodontal diseases were divided into four layers based on the quartered data.Poorer periodontal health condition(especially gingival index>1.1 and plaque index>1.5)had the correlation with IAs formation(p=0.007 and p<0.001).Conclusion:Severe gingivitis or periodontitis,combining with hypertension,is significantly associated with the incidence of IAs.展开更多
Ridge-furrow rainwater harvesting(RFRH)is known to be effective in controlling water loss and soil erosion,and increasing soil moisture and crop yield in semiarid regions.However,it can cause water-logging,ridge overt...Ridge-furrow rainwater harvesting(RFRH)is known to be effective in controlling water loss and soil erosion,and increasing soil moisture and crop yield in semiarid regions.However,it can cause water-logging,ridge overtopping,and harvest failure if not properly designed.A four consecutive-year field trial was carried out to assess the impacts of various slope gradients and tillage practices on soil moisture,runoff,sediment yield,associated soil nutrient losses,fodder yield,and water use efficiency(WUE)of alfalfa in the Loess Plateau,China.The trial adopted a split-plot design,taking slope gradient(5and 10)as main plot treatment and tillage practice(traditional tillage,open-ridging,and tied-ridging)as split-plot treatment,from 2015 to 2018.There were greater variations in runoff,sediment yield,and associ-ated soil nutrient losses than in fodder yield and WUE.Tied-ridging and open-ridging resulted in decreased runoff and reduced sediment transport and associated soil nutrient losses,and increased soil moisture,fodder yield,and WUE.Runoff,sediment transport,and associated soil nutrient losses inclined with increasing slope;while fodder yield and the WUE declined.For slopes of 5and 10,the average decrease in runoff,sediment yield,total nitrogen,total phosphorus,and organic matter losses for open-ridging were 47.7e56.2%,91.0e92.7%,90.4e93.1%,90.1e92.2%,and 88.9e90.2%,respectively,while these for tied-ridging were 62.4e68.4%,94.5e96.4%,93.6e95.5%,93.9e95.9%,and 93.0e94.9%,over 4 years as compared with traditional tillage.The mean annual runoff,sediment,total nitrogen,total phosphorus,and organic matter losses for slopes of 10were 1.31,1.96,1.87,1.99,and 1.64 times greater than the corresponding values for slopes of 5,respectively.The increase of fodder yield and WUE for open-ridging and tied-ridging was 40.1e45.6%and 16.0e17.5%,and 3.66e5.99 and 1.35e2.50 kg ha^(-1)mm^(-1),respectively,for slopes of 5and 10.The average fodder yield and WUE for slopes of 5were 1.19 and 1.23 times greater than corresponding values for slopes of 10,respectively.The disparities in fodder yield and WUE of alfalfa between slopes of 5and 10were not clear in dry years,but were evident in wet years.Tied-ridging was recommended for water and soil conservation,while open-ridging was recommended for increase of fodder yield and WUE of alfalfa.The implementation of RFRH in crop production should be evaluated by the use of a model in accordance with climatic conditions,soil type,and plant species.展开更多
Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems...Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems.This is because the degradation of fluorinated compounds under mild conditions remains a challenging task due to the strong C-F bond strength.In this study,we report preparation of PdRu@MIL-101 through immobilizing ultrafine PdRu alloy nanoparticles with a mean diameter of∼2 nminto the metal-organic framework(MOF),MIL-101(Cr),which was highly active and stable in the hydrodefluorination of 4-fluorophenol(4-FP)under mild aqueous conditions.The optimized catalyst Pd0.5Ru0.5@MIL-101 achieved impressive hydrogenation performance with a 98.5% conversion of 4-FP and a 97.7% selectivity of cyclohexanol,much better than the single metal-doped Pd@MIL-101 and Ru@MIL-101 catalysts.The excellent catalytic behavior contributed to the synergistic effect of combining the PdRu alloying effect and the MOF nanospace confinement effect,providing a promising strategy to develop highly efficient hydrodefluorination catalysts to assist environmental restoration and green ecology.展开更多
Metal-organic framework nanosheets (MOF NNs) offer potential opportunities for many applications,but an efficient strategy for the scalable preparation of few-layered two-dimensional (2D) MOF NNs are still a major cha...Metal-organic framework nanosheets (MOF NNs) offer potential opportunities for many applications,but an efficient strategy for the scalable preparation of few-layered two-dimensional (2D) MOF NNs are still a major challenge.Herein,we present an efficient top-down method for the synthesis of the Ni-BDC(Ni_(2)(OH)_(2)(1,4-BDC);1,4-BDC=1,4-benzenedicarboxylate) nanosheets utilizing a novel thermal expansionquench method of the flowerlike bulky MOFs in liquid N2.The obtained Ni-BDC nanosheets exhibit significantly enhanced photocatalytic performance of reductive CO_(2)deoxygenation (7.0μmol h^(-1)mg^(-1)) under visible light illumination compared with the bulky MOFs,due to much higher surface area for CO_(2)adsorption,more abundant active sites exposed and stronger electron transport ability of the nanosheets.More importantly,this synthetic strategy can be extended to fabricate other MOF nanosheets which also exhibit significantly improved performance for deoxygenative CO_(2)reduction compared to their bulky counterparts.This work may provide a guideline for preparing other 2D layered photocatalysts materials to realize energy conversion applications.展开更多
Dear Editor, TFL1homologues play a key role in the flowering habit of roses.To analyze the function of the newly isolated TFL1 gene of Rosa multiflora(Chen et al.,2013),named RoTFLlc,we performed overexpression analys...Dear Editor, TFL1homologues play a key role in the flowering habit of roses.To analyze the function of the newly isolated TFL1 gene of Rosa multiflora(Chen et al.,2013),named RoTFLlc,we performed overexpression analyses in Arabidopsis thaliana.When compared with empty vector control and wild type Arabidopsis plants,RoTFLlc overexpressing transgenic plants exhibited strong phenotypes such as a clustered habit,an increased number of rosette leaves, late flowering or failure to flower.展开更多
Alloy nanoparticles(NPs)with numerous exposed catalytic active sites have been extensively studied as efficient heterogeneous catalysts.However,it is challenging to synthesize alloy NP catalysts with high activity whi...Alloy nanoparticles(NPs)with numerous exposed catalytic active sites have been extensively studied as efficient heterogeneous catalysts.However,it is challenging to synthesize alloy NP catalysts with high activity while avoiding aggregation.Herein,we report a facile method to encapsulate alloy NPs loaded metal–organic framework(MOF)catalysts(alloy NPs/MOFs)within an ultrathin metal–organic layer using a terephthalic acid(BDC)assisted method.A series of metal-BDC encapsulated PtM/MOFs(M=Fe,Co,and Ni)catalysts were synthesized successfully and showed significantly enhanced catalytic performance toward selective hydrogenation reaction.展开更多
基金the financial support from the National Natural Science Foundation of China(22078272&22278340)。
文摘Building well-developed ion-conductive highways is highly desirable for anion exchange membranes(AEMs).Grafting side chain is a highly effective approach for constructing a well-defined phaseseparated morphological structure and forming unblocked ion pathways in AEMs for fast ion transport.Fluorination of side chains can further enhance phase separation due to the superhydrophobic nature of fluorine groups.However,their electronic effect on the alkaline stability of side chains and membranes is rarely reported.Here,fluorine-containing and fluorine-free side chains are introduced into the polyaromatic backbone in proper configuration to investigate the impact of the fluorine terminal group on the stability of the side chains and membrane properties.The poly(binaphthyl-co-p-terphenyl piperidinium)AEM(QBNp TP)has the highest molecular weight and most dimensional stability due to its favorable backbone arrangement among ortho-and meta-terphenyl based AEMs.Importantly,by introducing both a fluorinated piperidinium side chain and a hexane chain into the p-terphenyl-based backbone,the prepared AEM(QBNp TP-QFC)presents an enhanced conductivity(150.6 m S cm^(-1))and a constrained swelling at 80℃.The electronic effect of fluorinated side chains is contemplated by experiments and simulations.The results demonstrate that the presence of strong electro-withdrawing fluorine groups weakens the electronic cloud of adjacent C atoms,increasing OH^(-)attack on the C atom and improving the stability of piperidinium cations.Hence QBNp TP-QFC possesses a robust alkaline stability at 80℃(95.3%conductivity retention after testing in 2 M Na OH for 2160 h).An excellent peak power density of 1.44 W cm^(-2)and a remarkable durability at 80℃(4.5%voltage loss after 100 h)can be observed.
基金supported by the 100 Talents Plan Foundation of Sun Yat-sen UniversityThousand Youth Talents Plan of China and Guangdong Province+1 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (2017ZT07C069)the NSFC Projects (22075321, 21821003 and 21890380)。
文摘Bismuth (Bi) has indeed inspired great interests in lithium-ion batteries (LIBs) due to the high capacity,but was still limited by the low electrical conductivity and large volume variation.Herein,a composite material based on Bi nanoparticles in situ encapsulated by carbon film (Bi@CF) is prepared successfully through a facile metal–organic framework (MOF)-engaged approach.As anode materials for LIBs,the Bi@CF composites achieved high reversible capacities of 705 and 538 mAh g^(-1)at 0.2 and 0.5 A g^(-1) after200 cycles,and long cycling performance with a stable capacity of 306 mAh g^(-1)at 1.0 A g^(-1) even after 900 cycles.In situ X-ray diffraction (XRD) measurements clearly revealed the conversion between Bi and Li_(3)Bi during the alloying/dealloying process,confirming the good electrochemical reversibility of Bi@CF for Li-storage.The reaction kinetics of this Bi@CF composite was further studied by galvanostatic intermittent titration technique (GITT).This work may provide an inspiration for the elaborate design and facile preparation of alloy-type anode materials for high-performance rechargeable batteries.
基金This work was supported by the National Natural Science Foundation of China(No.51671105,51705244)Natural Science Foundation of Jiangsu Province(No.BK20170790)+2 种基金the Project Funded by China Postdoctoral Science Foundation(No.2019M661826)Fund of State Key Laboratory of Aerodynamics(SKLA2019020401)Open Fund of Key Laboratory of Icing and Anti/De-icing(No.IADL20190202).
文摘The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.
基金This work was funded by Guest Investigator Grant of the State Key Laboratory of Plant Genomics,Institute of Microbiology,Chinese Academy of Science(SKLPG2016A-29)。
文摘Rose(Rosa chinensis),which is an economically valuable floral species worldwide,has three types,namely once-flowering(OF),occasional or re-blooming(OR),and recurrent or continuous flowering(CF).However,the mechanism underlying the effect of the age pathway on the duration of the CF or OF juvenile phase is largely unknown.In this study,we observed that the RcSPL1 transcript levels were substantially upregulated during the floral development period in CF and OF plants.Additionally,accumulation of RcSPL1 protein was controlled by rch-miR156.The ectopic expression of RcSPL1 in Arabidopsis thaliana accelerated the vegetative phase transition and flowering.Furthermore,the transient overexpression of RcSPL1 in rose plants accelerated flowering,whereas silencing of RcSPL1 had the opposite phenotype.Accordingly,the transcription levels of floral meristem identity genes(APETALA1,FRUITFULL,and LEAFY)were significantly affected by the changes in RcSPL1 expression.RcTAF15b protein,which is an autonomous pathway protein,was revealed to interact with RcSPL1.The silencing and overexpression of RcTAF15b in rose plants led to delayed and accelerated flowering,respectively.Collectively,the study findings imply that RcSPL1–RcTAF15b modulates the flowering time of rose plants.
基金supported by The Thousand Talents Plan Foundation of China and Guangdong ProvinceThe 100 Talents Plan Foundation of Sun Yat-sen University (31000-18821107)+2 种基金the Program for Guangdong Introducing Innovative and Enterpreneurial Teams (2017ZT07C069)the NSFC Projects (21573291, 21720102007)the STP Project of Guangzhou (201504010031)
文摘The oxygen evolution reaction(OER) is the cornerstone for many important energy conversion devices, including metal–air battery and water splitting.Herein, an optimized NiFe-based metal–organic framework is developed as highly efficient active material for OER. It just needs a low overpotential of 0.31 V to deliver a current density of 10 mA cm-2 with a favorable Tafel slope of 43.7 mV dec-1 in 0.1 M KOH electrolyte for the as-prepared Ni0.75Fe0.25 BDC, which is superior to RuO2. This efficient catalytic performance is due to the introduction of Fe in Ni-based MOFs could benefit the kinetics and charge transfer efficiency, resulting in the optimal activity toward OER. Besides, the obtained active material demonstrates good stability, suggesting the great potential value in sustainable electrochemical energy storage and conversion devices.
基金the National Natural Science Foundation of China(Grant No.31560380)Chief Expert of Modern Agricultural Traditional Chinese Medicine Industry System in Gansu Province(GARS-ZYC-1)the Open Project of Qinghai Key Laboratory of Qinghai-Tibet Plateau Biological Resources(Grant No.2017-ZJ-Y10)。
文摘In order to further understand the effects of drought stress on hydraulic characteristics and the relationship between hydraulic conductivity and aquaporins or water channels of root systems of three wolfberry cultivars(Lycium chinense Mill.),hydraulic conductivity of 2-yearold pot-grown seedlings was measured under drought stress,rewatering,and treatment with exogenous mercuric chloride andβ-mercaptoethanol.Under moderate and severe drought stress levels,the most significant decrease of hydraulic conductivity was 37.3%and 24.0%,respectively,in the‘Ningqi 5’cultivar compared with the nonstressed control.After rewatering,the rate of recovery in specific conductivity was most rapid in the‘Mengqi 1’cultivar,at 0.058 and 0.072 kg MPa^-1 m^-2 s^-1 h^-1 under moderate and severe drought stress levels,respectively.The‘Mengqi 1’cultivar had the highest recovery degree of hydraulic conductivity under two concentrations ofβ-ME(500 or 1000 lmol L^-1),reaching 82.4%and 88.5%,respectively,of the initial conductivity.The adaptive capacity of hydraulic conductivity in the‘Ningqi 5’cultivar was weaker than in the‘Ningqi 1’and‘Mengqi 1’cultivars under drought stress.The recovery capacity of hydraulic conductivity in‘Mengqi 1’cultivar was stronger than the‘Ningqi 1’and‘Ningqi 5’cultivars after rewatering.Aquaporins of the‘Ningqi 1’cultivar root systems had the highest binding affinity with mercuric chloride,which was the most likely cause in the decrease in hydraulic conductivity,whereas aquaporins of‘Mengqi 1’root systems had the weakest binding affinity.The inhibitory effect of mercuric chloride was readily eliminated byβ-mercaptoethanol in the‘Mengqi 1’cultivar.The hydraulic characteristics of this cultivar were more sensitive to drought,mercuric chloride andβ-mercaptoethanol than the other cultivars.
基金This work was supported by grants from the National Natural Science Foundation of China(Grant No.31800601).
文摘Studying the genetic basis and regulatory mechanism of chrysanthemum lateral bud outgrowth is of great significance for reduction the production cost of cut chrysanthemum.To clarify the molecular basis of lateral bud elongation after removal of apical dominance in chrysanthemum,label-free quantification analysis was used to analyze the proteome changes after apical bud removal.Quantitative real-time PCR(qPCR)was used to analyze the changes in the expression of three plant hormone-related genes.A total of 440 differentially expressed proteins were successfully identified at three time points during the lateral bud elongation.The number of differentially expressed proteins in the three stages(24 h/0 h,48 h/0 h,48 h/24 h)were 219,332,and 97,respectively.The difference in expressed proteins in the three comparison stages mainly involves RNA processing and modification;translation,ribosomal structure and biogenesis;Posttranslational modification,protein turnover,and chaperones.Path analysis showed that there was various physiological activities in the process of lateral bud dormancy breaking and elongation,which involved energy metabolism,biosynthesis,signal transduction and stress response in the growth process of lateral buds.qPCR indicated that the expression of cytokinin synthesis related gene was significantly increased after the removal of apical dominance,while the expression of strigolactones synthesis related gene experiences a dramatic fall to promote the development of the lateral buds.However,there was a drop before a slight increase in the expression of the auxin synthesis related gene,which was mainly due to the removal of apical dominance that led to the loss of indoleacetic acid in the main stem.However,with formation of the new apical source,indoleacetic acid can be released again.
基金supported by National Key R&D Program of China(No.2018YFA0108300)the Overseas High-level Talents Plan of China and Guangdong Province+3 种基金the 100 Talents Plan Foundation of Sun Yat-sen Universitythe Fundamental Research Funds for the Central Universitiesthe Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2017ZT07C069)the NSFC Projects(Nos.21905315 and 22075321)。
文摘Although the selective hydrogenation ofα,β-unsaturated aldehyde to unsaturated alcohol(UOL)is an extremely important transformation,it is still a great challenge to achieve high selectivity to UOL due to thermodynamic favoring of the C=C hydrogenation over the C=O hydrogenation.Herein,we report that iridium nanoclusters(Ir NCs)confined within hollow MIL-101(Fe)expresses satisfied reaction activity(93.9%)and high selectivity(96.2%)for the hydrogenation of cinnamaldehyde(CAL)to cinnamyl alcohol(COL)under 1 bar H;atmosphere and room temperature.The unique hollow structure of MIL-101(Fe)benefits for the fast transport of reactant,ensuring the comparable reaction activity and better recyclability of Ir@MIL-101(Fe)than the counterparts which Ir NCs were on the surface of MIL-101(Fe).Furthermore,The X-ray photoelectron spectroscopy data indicates the electropositive Ir NCs,owing to the electron transfer from Ir to MIL-101(Fe),can interact with oxygen lone pairs,and Fourier transform infrared spectrum shows the Lewis acid sites in MIL-101(Fe)can strongly interact with C=O bond,which contributes to a high selectivity for COL.This work suggests the considerable potential of synergetic effect between hollow MOFs and metal nanoclusters for selective hydrogenation reactions.
基金supported by National Key R&D Program of China (No.2018YFA0108300)the Overseas High-level Talents Plan of China and Guangdong Province+3 种基金the Fundamental Research Funds for the Central Universitiesthe 100 Talents Plan Foundation of Sun Yat-sen Universitythe Program for Guangdong Introducing Innovative and Entrepreneurial Teams (No.2017ZT07C069)the Natinoal Natural Science Foundation of China (Nos.22075321,21821003,21890380 and 21905315)。
文摘Exploring platinum group metal-free electrocatalysts with superior catalytic performance and favorable durability for oxygen reduction reaction is a remaining bottleneck in process of developing sustainable techniques in energy storage and conversion. Herein, a hierarchical porous single atomic Fe electrocatalyst(Fe/Z8-E-C) is rationally designed and synthesized via acid etching, calcination, adsorption of Fe precursor and recalcination processes. This unique electrocatalyst Fe/Z8-E-C shows excellent oxygen reduction performance with a half-wave potential of 0.89 V in 0.1 mol/L KOH, 30 m V superior to that of commercial Pt/C(0.86 V), which is also significantly higher than that of typical Fe-doped ZIF-8 derived carbon nanoparticles(Fe/Z8-C) with a half-wave potential of 0.84 V. Furthermore, Fe/Z8-E-C-based Zn-air battery exhibits greatly enhanced peak power density and specific capacity than those of original Fe/Z8-C,verifying the remarkable performance and practicability of this specially designed hierarchical structure due to its efficient utilization of the active sites and rapid mass transfer. This present work proposes a new method to rationally synthesize single atom electrocatalysts loaded on hierarchical porous frame materials for catalysis and energy conversion.
基金This study was supported by the National Natural Science Foundation(81471166)Capital Medical Development Research Foundation of China(2016-1-1075).
文摘Background:We investigated whether periodontal diseases,specifically,periodontitis and gingivitis,could be risk factors of the incidence of intracranial aneurysms(IAs).Methods:We performed a case–control study to compare the differences in the periodontal disease parameters of 281 cases that were divided into the IAs group and non-IAs group.All cases underwent complete radiographic examination for IAs and examination for periodontal health.Results:Comparing with those in the non-IAs group,the cases in the IAs group were older(53.95±8.56 vs 47.79±12.33,p<0.001)and had a higher incidence of hypertension(76 vs 34,p=0.006).Univariate logistic regression analysis revealed that age(>50 years)and hypertension were predictive risk factors of aneurysm formation(odds ratio[OR]1.047,95%confidence interval[95%CI]1.022–1.073,p<0.001 and OR 2.047,95%CI 1.232–3.401,p=0.006).In addition,univariate and multivariate logistic regression analyses showed that the parameters of periodontal diseases,including gingival index,plaque index,clinical attachment loss,and alveolar bone loss,were significantly associated with the occurrence of IAs(all p<0.05).For further statistical investigation,the parameters of periodontal diseases were divided into four layers based on the quartered data.Poorer periodontal health condition(especially gingival index>1.1 and plaque index>1.5)had the correlation with IAs formation(p=0.007 and p<0.001).Conclusion:Severe gingivitis or periodontitis,combining with hypertension,is significantly associated with the incidence of IAs.
基金the National Natural Science Foundation of China(42061050,41661059 and 41775107).
文摘Ridge-furrow rainwater harvesting(RFRH)is known to be effective in controlling water loss and soil erosion,and increasing soil moisture and crop yield in semiarid regions.However,it can cause water-logging,ridge overtopping,and harvest failure if not properly designed.A four consecutive-year field trial was carried out to assess the impacts of various slope gradients and tillage practices on soil moisture,runoff,sediment yield,associated soil nutrient losses,fodder yield,and water use efficiency(WUE)of alfalfa in the Loess Plateau,China.The trial adopted a split-plot design,taking slope gradient(5and 10)as main plot treatment and tillage practice(traditional tillage,open-ridging,and tied-ridging)as split-plot treatment,from 2015 to 2018.There were greater variations in runoff,sediment yield,and associ-ated soil nutrient losses than in fodder yield and WUE.Tied-ridging and open-ridging resulted in decreased runoff and reduced sediment transport and associated soil nutrient losses,and increased soil moisture,fodder yield,and WUE.Runoff,sediment transport,and associated soil nutrient losses inclined with increasing slope;while fodder yield and the WUE declined.For slopes of 5and 10,the average decrease in runoff,sediment yield,total nitrogen,total phosphorus,and organic matter losses for open-ridging were 47.7e56.2%,91.0e92.7%,90.4e93.1%,90.1e92.2%,and 88.9e90.2%,respectively,while these for tied-ridging were 62.4e68.4%,94.5e96.4%,93.6e95.5%,93.9e95.9%,and 93.0e94.9%,over 4 years as compared with traditional tillage.The mean annual runoff,sediment,total nitrogen,total phosphorus,and organic matter losses for slopes of 10were 1.31,1.96,1.87,1.99,and 1.64 times greater than the corresponding values for slopes of 5,respectively.The increase of fodder yield and WUE for open-ridging and tied-ridging was 40.1e45.6%and 16.0e17.5%,and 3.66e5.99 and 1.35e2.50 kg ha^(-1)mm^(-1),respectively,for slopes of 5and 10.The average fodder yield and WUE for slopes of 5were 1.19 and 1.23 times greater than corresponding values for slopes of 10,respectively.The disparities in fodder yield and WUE of alfalfa between slopes of 5and 10were not clear in dry years,but were evident in wet years.Tied-ridging was recommended for water and soil conservation,while open-ridging was recommended for increase of fodder yield and WUE of alfalfa.The implementation of RFRH in crop production should be evaluated by the use of a model in accordance with climatic conditions,soil type,and plant species.
基金supported by the National Key R&D Program of China(no.2018YFA0108300)the Overseas High-level Talents Plan of China and Guangdong Province,the Fundamental Research Funds for the Central Universities+2 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(no.2017Z T07C069)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(no.2017BT01C161)the NSFC Projects(nos.22075321,21821003,21890380,and 21905315).
文摘Fluorinated organic compounds are of great importance to modern industries,while their release to the environment is inevitable,causing extreme environmental pollution and the subsequent hazardous effect on ecosystems.This is because the degradation of fluorinated compounds under mild conditions remains a challenging task due to the strong C-F bond strength.In this study,we report preparation of PdRu@MIL-101 through immobilizing ultrafine PdRu alloy nanoparticles with a mean diameter of∼2 nminto the metal-organic framework(MOF),MIL-101(Cr),which was highly active and stable in the hydrodefluorination of 4-fluorophenol(4-FP)under mild aqueous conditions.The optimized catalyst Pd0.5Ru0.5@MIL-101 achieved impressive hydrogenation performance with a 98.5% conversion of 4-FP and a 97.7% selectivity of cyclohexanol,much better than the single metal-doped Pd@MIL-101 and Ru@MIL-101 catalysts.The excellent catalytic behavior contributed to the synergistic effect of combining the PdRu alloying effect and the MOF nanospace confinement effect,providing a promising strategy to develop highly efficient hydrodefluorination catalysts to assist environmental restoration and green ecology.
基金financially supported by the Overseas Highlevel Talents Plan of China and Guangdong Provincethe Fundamental Research Funds for the Central Universities, the 100 Talents Plan Foundation of Sun Yat-sen University+3 种基金the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (No. 2017ZT07C069)National Key R&D Program of China (No. 2018YFA0108300)Local Innovative and Research Teams Project of Guangdong Peal River Talents Program (No. 2017BT01C161)the NSFC Projects (Nos. 22075321, 21821003, 21890380 and 21905315)。
文摘Metal-organic framework nanosheets (MOF NNs) offer potential opportunities for many applications,but an efficient strategy for the scalable preparation of few-layered two-dimensional (2D) MOF NNs are still a major challenge.Herein,we present an efficient top-down method for the synthesis of the Ni-BDC(Ni_(2)(OH)_(2)(1,4-BDC);1,4-BDC=1,4-benzenedicarboxylate) nanosheets utilizing a novel thermal expansionquench method of the flowerlike bulky MOFs in liquid N2.The obtained Ni-BDC nanosheets exhibit significantly enhanced photocatalytic performance of reductive CO_(2)deoxygenation (7.0μmol h^(-1)mg^(-1)) under visible light illumination compared with the bulky MOFs,due to much higher surface area for CO_(2)adsorption,more abundant active sites exposed and stronger electron transport ability of the nanosheets.More importantly,this synthetic strategy can be extended to fabricate other MOF nanosheets which also exhibit significantly improved performance for deoxygenative CO_(2)reduction compared to their bulky counterparts.This work may provide a guideline for preparing other 2D layered photocatalysts materials to realize energy conversion applications.
基金supported by the National High-tech R&D Program (2011AA100208)the State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences (2016A0219-24)
文摘Dear Editor, TFL1homologues play a key role in the flowering habit of roses.To analyze the function of the newly isolated TFL1 gene of Rosa multiflora(Chen et al.,2013),named RoTFLlc,we performed overexpression analyses in Arabidopsis thaliana.When compared with empty vector control and wild type Arabidopsis plants,RoTFLlc overexpressing transgenic plants exhibited strong phenotypes such as a clustered habit,an increased number of rosette leaves, late flowering or failure to flower.
基金supported by funding from the National Key R&D Program of China(no.2018YFA0108300)the Overseas High-level Talents Plan of China and Guangdong Province,the Fundamental Research Funds for the Central Universities+3 种基金the 100 Talents Plan Foundation of Sun Yat-sen Universitythe Program for Guangdong Introducing Innovative and Entrepreneurial Teams(no.2017ZT07C069)the NSFC Projects(nos.22075321,21821003,and 21890380)the China Postdoctoral Science Foundation(nos.2019M653141 and 2020M682042).
文摘Alloy nanoparticles(NPs)with numerous exposed catalytic active sites have been extensively studied as efficient heterogeneous catalysts.However,it is challenging to synthesize alloy NP catalysts with high activity while avoiding aggregation.Herein,we report a facile method to encapsulate alloy NPs loaded metal–organic framework(MOF)catalysts(alloy NPs/MOFs)within an ultrathin metal–organic layer using a terephthalic acid(BDC)assisted method.A series of metal-BDC encapsulated PtM/MOFs(M=Fe,Co,and Ni)catalysts were synthesized successfully and showed significantly enhanced catalytic performance toward selective hydrogenation reaction.
