Thermotropic liquid crystalline VHE terpolyesters made from vanillic acid (V),p-hydroxybenzoic acid (H) and poly(ethylene terephthalate) (E) were studied by 400 MHz NMR spectra, wide angle X-ray diffraction,scanning e...Thermotropic liquid crystalline VHE terpolyesters made from vanillic acid (V),p-hydroxybenzoic acid (H) and poly(ethylene terephthalate) (E) were studied by 400 MHz NMR spectra, wide angle X-ray diffraction,scanning electron and polarizing microscopes.It was found that the VHE terpolyesters had random sequence distribution.The VHE terpolyester films exhibited highly oriented fibrillar structure.展开更多
Ethylene glycol(EG)is a biomass derivative of polyethylene terephthalate(PET),and its electrocatalytic conversion into high-value chemicals has sparked widespread interest.This study reviews the most recent research d...Ethylene glycol(EG)is a biomass derivative of polyethylene terephthalate(PET),and its electrocatalytic conversion into high-value chemicals has sparked widespread interest.This study reviews the most recent research development in electrocatalysis-based EG to glycolic acid(GA)conversion.Firstly,the strategies and research results of modulating the electronic structure of catalysts for efficient selective GA production from EG are reviewed.Second,by reviewing the data of in-situ Fourier transform infrared spectroscopy and in-situ electrochemically attenuated total reflection surface enhanced infrared absorption spectroscopy,the reaction pathway and catalytic mechanism of EG partial oxidation to GA were clarified.Finally,the design and regulation of catalysts for selective oxidation of EG by electrocatalysis in the future are prospected.展开更多
Electrocatalytic oxidation of surplus ethylene glycol(EG)to high-value glycolic acid(GA)represents a promising approach for sustainable resource utilization,though critical challenges persist in developing durable ele...Electrocatalytic oxidation of surplus ethylene glycol(EG)to high-value glycolic acid(GA)represents a promising approach for sustainable resource utilization,though critical challenges persist in developing durable electrocatalysts and achieving effective recovery of the free acid product from its salt derivatives in alkaline electrolytes.In this work,a PdNi/NF catalyst was rationally synthesized via a one-step electrodeposition method.Systematic characterization revealed that the electron transfer from Ni to Pd modulates *OH adsorption to accelerate EG oxidation reaction(EGOR)while preventing Pd deactivation through oxidation.The optimized system demonstrated exceptional alkaline performance with a glycolic acid Faraday efficiencyof 95%and a current density of 666 mA·cm^(-2).When implemented in an asymmetric EGOR||HER flowcell configuration where only the cathodic electrolyte contains alkaline,the system demonstrated exceptional operational stability by sustaining 70 mA·cm^(-2) current density at a low cell voltage of 0.9 V in neutral media for over 100 h,with product glycolic acid requiring no further acidification.This investigation provides a practical framework for designing efficientelectrocatalytic systems that simplifiesproduct separation steps.展开更多
Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephth...Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephthalate(PET)due to its enhanced material properties.However,the fabrication of PEF with stable and desirable properties is still a challenge,largely due to the impurities in FDCA.In this study,a highly efficient purification strategy for FDCA was proposed,utilizing a dioxane/H_(2)O binary solvent system for effective crystallization.Furthermore,PEFs were synthesized from FDCA with varying impurity and the effects of these impurities were systematically characterized.The results revealed that impurities in FDCA could result in PEFs with relatively poor thermal properties.This study provides crucial insights for the impact of impurities on PEF properties and FDCA purification.展开更多
Autophagy is a universal cellular process in eukaryotes that plays a critical role in plant growth and stress response.However,the role of autophagy in fruit ripening is largely unknown.Here,we demonstrated that most ...Autophagy is a universal cellular process in eukaryotes that plays a critical role in plant growth and stress response.However,the role of autophagy in fruit ripening is largely unknown.Here,we demonstrated that most autophagy-related genes(ATGs)were up-regulated during tomato(Solanum lycopersicum L.)fruit ripening.By using mutants of different autophagy pathway genes(ATG6,ATG10,ATG18a),we revealed that the deficiency of autophagy delayed the ripening of fruit.Compared with wild-type(WT),the production of ethylene was significantly reduced and the accumulation of lycopene was delayed in atg mutants during fruit ripening.We also observed the contents of glucose and fructose were both significantly decreased in atg mutants compared with WT,while the content of organic acids showed the opposite trend.Additionally,the negative regulator of ethylene production,APETALA2a(AP2a),interacted with ATG8 through a specific ATG8-interacting motif(AIM)and could be degraded through the autophagy pathway.These results demonstrate that autophagy plays a critical role in fruit ripening by regulating ethylene production and the accumulation of pigments,sugars and organic acids in tomato.展开更多
A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use...A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use daily plastics,polyethylene terephthalate(PET),has recently been investigated in terms of chemical recycling to reduce its environmental impact and generate renewable fuels.This study introduces an innovative electrochemical method for the specific conversion of PET hydrolysate into highvalue compounds utilizing CoCuO_(x)@MXene/NF catalyst.Our findings revealed that the electrocatalyst was capable of facilitating the conversion of water into hydrogen(H_(2)),while simultaneously oxidizing ethylene glycol(EG),obtained from PET plastic waste hydrolysis,into formate with a high selectivity and lower initial potential compared to water oxidation.Notably,the exceptional performance was attributed to the synergistic interfacial electronic coupling effect between CoCuO_(x)and MXene,which results in a low overpotential(1.24 V@10 mA cm^(-2))and a high yield of formate product(87.6%).In addition,the electrolyzer could be operated using solar energy panel for upcycling of PET to formic acid and hydrogen fuels by using CoCuO_(x)@MXene catalyst.展开更多
Kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson cv. Bruno) was used toinvestigate the effects of acetylsalicylic acid (ASA, 1.0 mmol/L, pH 3.5) and ethylene (100 mL/L) treat-ments on changes at...Kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson cv. Bruno) was used toinvestigate the effects of acetylsalicylic acid (ASA, 1.0 mmol/L, pH 3.5) and ethylene (100 mL/L) treat-ments on changes at endogenous salicylic acid (SA) levels and other senescence-related factors duringfruit ripening and softening at 20 ℃. The level of endogenous SA in ripening fruits declined and a closerelationship was observed between the change at endogenous SA level and the rate of fruit ripening andsoftening. ASA treatment elevated SA level in the fruit, slowed down the increases in lipoxygenase (LOX)and allene oxide synthase (AOS) activities, decreased the O22-. production in the preclimacteric phase andthe early phase of ethylene climacteric rise, maintained the stability of cell membrane, inhibited ethylenebiosynthesis, postponed the onset of the ethylene climacteric, and delayed the process of fruit ripeningand softening. On the contrary, application of ethylene to ripening kiwifruit resulted at a lower SA level, anaccelerated increases in the activities of LOX and AOS and the rate of O22-. production, an elevated relativeelectric conductivity and an advanced onset of ethylene climacteric, and a quicker fruit ripening andsoftening. It is suggested that the effects of ASA on ripening kiwifruit can be attributed to its ability toscavenge O22-. and/or to maintain stability of cell membrane.展开更多
Glutaredoxins are small heat-stable oxidoreductases that transfer electrons from glutathione （GSH） to oxi- dized cysteine residues, thereby contributing to protein integrity and regulation. In Arabidopsis thaliana, ...Glutaredoxins are small heat-stable oxidoreductases that transfer electrons from glutathione （GSH） to oxi- dized cysteine residues, thereby contributing to protein integrity and regulation. In Arabidopsis thaliana, floral glutare- doxins ROXY1 and ROXY2 and pathogen-induced ROXY19/GRX480 interact with bZIP transcription factors of the TGACG （TGA） motif-binding family. ROXY1, ROXY2, and TGA factors PERIANTHIA, TGA9, and TGA10 play essential roles in floral development. In contrast, ectopically expressed ROXY19/GRX480 negatively regulates expression of jasmonic acid （JA）/ ethylene （ET）-induced defense genes through an unknown mechanism that requires clade II transcription factors TGA2, TGA5, and/or TGA6. Here, we report that at least 17 of the 21 land plant-specific glutaredoxins encoded in the Arabidopsis genome interact with TGA2 in a yeast-two-hybrid system. To investigate their capacity to interfere with the expression of JA/ET-induced genes, we developed a transient expression system. Activation of the ORA59 （OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF-domain protein 59） promoter by transcription factor EIN3 （ETHYLENE INSENSITVE 3） was sup- pressed by co-expressed ROXY19/GRX480. Suppression depended on the L＊＊LL motif in the C-terminus of ROXY19/ GRX480. This putative protein interaction domain was recently described as being essential for the TGA/ROXY interaction. Ten of the 17 tested ROXY proteins suppressed ORA59 promoter activity, which correlated with the presence of the C-terminal ALWL motif, which is essential for ROXY1 function in flower development. ROXY19/GRX480-mediated repres- sion depended on the GSH binding site, suggesting that redox modification of either TGA factors or as yet unknown target proteins is important for the suppression of ORA59 promoter activity.展开更多
The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic...The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.展开更多
Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids,prior to activation by triethylaluminum, in order to increase their activity in ethylene polymeriz...Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids,prior to activation by triethylaluminum, in order to increase their activity in ethylene polymerization. BCl3 provided the highest increase in activity. Interestingly, polymerization results showed no substantial modification of polymer properties, which is consistent with that Lewis acid only promotes the creation of new active sites, after activation by TEA, possessing very similar features to the original ones achievable with conventional precatalysts(i.e. without Lewis-acid treatment).展开更多
To elucidate the relationship between ethylene evolution from the grains and the appearance quality of rice, ten different rice genotypes were used to determine the ethylene evolution rate, 1-aminocylopropane-1-carbox...To elucidate the relationship between ethylene evolution from the grains and the appearance quality of rice, ten different rice genotypes were used to determine the ethylene evolution rate, 1-aminocylopropane-1-carboxylic acid （ACC） concentration in grains during grain filling and the appearance quality of rice, and the effects of chemical regulators on concentrations of ethylene and ACC in the grains during grain filling were also investigated to verify the roles of ethylene in the rice quality formation. The ethylene evolution rates and ACC concentrations in grains during the mid and late grain filling stages were very significantly and positively correlated with chalky kernel percentage and chalkiness. The cultivars with a low ACC concentration in grains exhibited a close amyloplast arrangement and small space between starch granules, whereas those with a high ACC concentration in grains showed a loose arrangement and wide space between the granules. Application of 1 μmol/L ACC to panicles at mid and late grain filling stages significantly loosened amyloplast arrangement and increased chalky kernel percentage, chalky area and chalkiness, and the results were reversed when 1 μmol/L amino-ethoxyvinylglycine, an inhibitor of ACC synthesis enzyme, was applied to panicles. A practice of moderate dry-wet alternate irrigation reduced ethylene evolution and ACC concentration in grains and thereby reduced chalkiness. The results suggested that ethylene and ACC in grains play an important role in the endosperm structure and appearance quality of rice, and the appearance quality would be improved by reducing ethylene evolution and ACC in grains through either variety breeding and selection, or chemical regulations or cultivation techniques.展开更多
The oligomerization of ethylene in FCC dry gas over HZSM-5 catalyst with different Si/A12 ratios was studied. The effect of acid density of catalyst on the oligomerization of ethylene was discussed. By increasing the ...The oligomerization of ethylene in FCC dry gas over HZSM-5 catalyst with different Si/A12 ratios was studied. The effect of acid density of catalyst on the oligomerization of ethylene was discussed. By increasing the acid density of catalyst, ethylene conversion showed a linear increase, while the yields of olefins decreased when the acid density of catalyst exceeded 0.14mmolNH3/g owing to a promotion of hydrogen transfer reaction. Through comparing the average distance between acid sites on catalyst with kinetic diameters of olefins, it was found that the dimerization of ethylene was not restrained by the sparse distribution of acid sites, while the hydrogen transfer reaction of C3 and C4 olefins was limited. On these bases, a conclusion is proposed that the dimerization of ethylene proceeded via Eley-Rideal mechanism, while the hydrogen transfer reaction of C3 and C4 olefins followed the Langmuir-Hinshelwood mechanism.展开更多
Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and ...Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn2（dpe）0.5（mna）2] （1） can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn（Ⅱ） and mna ligands is bridged by dpe ligands, while the complex named [Zn4（dpe）4（mna）4] （2） is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C–H…π and π…π interactions. Compound 3 with general formular [Cd2（dpe）0.5（mna）2]·H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd（Ⅱ） and mna ligands are connected with the bridging of dpe ligands.展开更多
Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with differ...Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.展开更多
Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techni...Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.展开更多
The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The s...The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The statically saturated adsorption capacity is 181 mg/(g resin). Cu(Ⅱ) adsorbed on APAR can be eluted by 1 0-3 0 mol/L HCl. The rate constant is k 298 =5 58×10 -5 s -1 . The adsorption of Cu(Ⅱ) on APAR follows the Freundlich isotherm. The Δ H of the adsorption is 3 91 kJ/mol. The apparent activation energy is E a=21 4 kJ/mol. The coordination molar ratio of APAR to Cu(Ⅱ) is 1/1. It is shown that the nitrogen and the oxygen atoms in the functional group of APAR coordinate to Cu(Ⅱ).展开更多
Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate lig...Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.展开更多
The effects of adding poly （ethylene glycol） （PEG） into polylactic acid/thermoplastic starch blends （PLA/TPS） on the properties were investigated by DSC, SEM and mechanical property-testing. The blends of PLA/TP...The effects of adding poly （ethylene glycol） （PEG） into polylactic acid/thermoplastic starch blends （PLA/TPS） on the properties were investigated by DSC, SEM and mechanical property-testing. The blends of PLA/TPS blended with increasing content PEG exhibited lower temperature of glass transition （T） and lower temperature of melting （T） as well as higher melt flow index （MFI）, which indicates the plasticization and proeessability of the composites were dramatically improved. The tensile strength, flexural strength and izod impact strength of PLA/TPS （80/20） increased at first and then decreased with increasing content of PEG due to stronger interfacial adhesion. The optimized mechanical property can be obtained for the blend with 3 wt % PEG. The samples containing PEG after soil burial for 5 months showed quicker degradation being accompanied with large weight loss and mechanical properties loss.展开更多
The regulation of apple(Malus domestica)fruit texture during ripening is complex and a fundamental determinant of its commercial quality.In climacteric fruit,ripening-related processes are regulated by ethylene(ET),an...The regulation of apple(Malus domestica)fruit texture during ripening is complex and a fundamental determinant of its commercial quality.In climacteric fruit,ripening-related processes are regulated by ethylene(ET),and jasmonate(JA)is also involved in the ethylene biosynthesis pathway,mainly through the transcription factor MYC2.However,the molecular genetic mechanism for fruit ripening processes between the JA and ET signaling pathways still needs to be elucidated.In order to explore how JA regulates apple fruit ripening through ERF4,we used’Gala’and’Ralls Janet’fruit at different developmental stages as experimental materials to determine the fruit firmness and related gene expression analysis.Meanwhile,we carried out different hormone treatments on’Gala’fruit at ripening stage.Here,we show that ERF4 is a core JA signaling hub protein JASMONATE ZIM-DOMAIN(JAZ)interactor that affects ethylene signaling pathways.During fruit development,ERF4 represses the expression of ACS1 and ACO1 by interacting with JAZ,as well as with the JA-activated transcription factor MYC2.Ripening is promoted in JAZ-suppressed apples.Thus,ERF4 acts as a molecular link between ethylene and JA hormone signals,and the natural variation of the ERF4Ethylene-responsive binding factor-associated amphiphilic repression(EAR)motif decreases repression of ethylene biosynthesis genes.展开更多
In order to obtain a uniform and effectively toughened poly(lactic acid)film by blending with low content of poly(ethylene octene)(POE)with high elasticity,the tailored interfacial intermolecular interaction and entan...In order to obtain a uniform and effectively toughened poly(lactic acid)film by blending with low content of poly(ethylene octene)(POE)with high elasticity,the tailored interfacial intermolecular interaction and entanglement between the two phases of the PLA/POE blend was innovatively constructed via the facile reactive melt blending process through the reaction of the epoxy/anhydride groups grafted on the POE chains with the end groups of PLA chains(PLA/GPOE-MPOE).It was observed that POE domains were embedded tightly in PLA matrix with a fuzzy interface and abundant interface transition area,and the impact fractured surface of the blend showed an obvious plastic deformation with less occurrence of fibrillation of PLA matrix or interfacial de-bonding.Compared with neat PLA and directly blended PLA/POE blends,the PLA/GPOE-MPOE blend exhibited much higher complex viscosity/storage modulus,much lower tanδvalues in the terminal region,and obvious strain-hardening behavior.The deviation in viscoelastic behavior of PLA/GPOE-MPOE from linear PLA indicated the enhanced molecular entanglement between the long-branched chains,resulting in an enhancement of the stretching ability during biaxial drawing of the blend.Uniform PLA/GPOE-MPOE films with draw ratio as high as 7×7 were obtained through biaxial stretching,which showed much higher tensile strength and the elongation at break than that of neat PLA and PLA/POE film.This work provides a facile method for fabricating toughening PLA films with application potentials.展开更多
文摘Thermotropic liquid crystalline VHE terpolyesters made from vanillic acid (V),p-hydroxybenzoic acid (H) and poly(ethylene terephthalate) (E) were studied by 400 MHz NMR spectra, wide angle X-ray diffraction,scanning electron and polarizing microscopes.It was found that the VHE terpolyesters had random sequence distribution.The VHE terpolyester films exhibited highly oriented fibrillar structure.
文摘Ethylene glycol(EG)is a biomass derivative of polyethylene terephthalate(PET),and its electrocatalytic conversion into high-value chemicals has sparked widespread interest.This study reviews the most recent research development in electrocatalysis-based EG to glycolic acid(GA)conversion.Firstly,the strategies and research results of modulating the electronic structure of catalysts for efficient selective GA production from EG are reviewed.Second,by reviewing the data of in-situ Fourier transform infrared spectroscopy and in-situ electrochemically attenuated total reflection surface enhanced infrared absorption spectroscopy,the reaction pathway and catalytic mechanism of EG partial oxidation to GA were clarified.Finally,the design and regulation of catalysts for selective oxidation of EG by electrocatalysis in the future are prospected.
基金financially supported by the National Key Research and Development Program of China(2022YFA1504200)the National Natural Science Foundation of China(22178033 and 22090030)the Fundamental Research Funds for the Central Universities(2024CDJXY010).
文摘Electrocatalytic oxidation of surplus ethylene glycol(EG)to high-value glycolic acid(GA)represents a promising approach for sustainable resource utilization,though critical challenges persist in developing durable electrocatalysts and achieving effective recovery of the free acid product from its salt derivatives in alkaline electrolytes.In this work,a PdNi/NF catalyst was rationally synthesized via a one-step electrodeposition method.Systematic characterization revealed that the electron transfer from Ni to Pd modulates *OH adsorption to accelerate EG oxidation reaction(EGOR)while preventing Pd deactivation through oxidation.The optimized system demonstrated exceptional alkaline performance with a glycolic acid Faraday efficiencyof 95%and a current density of 666 mA·cm^(-2).When implemented in an asymmetric EGOR||HER flowcell configuration where only the cathodic electrolyte contains alkaline,the system demonstrated exceptional operational stability by sustaining 70 mA·cm^(-2) current density at a low cell voltage of 0.9 V in neutral media for over 100 h,with product glycolic acid requiring no further acidification.This investigation provides a practical framework for designing efficientelectrocatalytic systems that simplifiesproduct separation steps.
基金supported by the National Natural Science Foundation of China(22378338,U22A20421)the Project for Science and Technology Plan of Fujian Province of China(2024H4007)。
文摘Poly(ethylene 2,5-furandicarboxylate)(PEF),a bioplastic synthesized via the polymerization of 2,5-furandicarboxylic acid(FDCA)with ethylene glycol,can be served as a substitute to petroleum-based polyethylene terephthalate(PET)due to its enhanced material properties.However,the fabrication of PEF with stable and desirable properties is still a challenge,largely due to the impurities in FDCA.In this study,a highly efficient purification strategy for FDCA was proposed,utilizing a dioxane/H_(2)O binary solvent system for effective crystallization.Furthermore,PEFs were synthesized from FDCA with varying impurity and the effects of these impurities were systematically characterized.The results revealed that impurities in FDCA could result in PEFs with relatively poor thermal properties.This study provides crucial insights for the impact of impurities on PEF properties and FDCA purification.
基金supported by the National Natural Science Foundation of China(Grant Nos.32302642,32272790)the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(Grant No.SN-ZJU-SIAS-0011)+1 种基金Collaborative Promotion Program of Zhejiang Provincial Agricultural Technology of China(Grant No.2023ZDXT05)the Fundamental Research Funds for the Central Universities(Grant No.226-2022-00122).
文摘Autophagy is a universal cellular process in eukaryotes that plays a critical role in plant growth and stress response.However,the role of autophagy in fruit ripening is largely unknown.Here,we demonstrated that most autophagy-related genes(ATGs)were up-regulated during tomato(Solanum lycopersicum L.)fruit ripening.By using mutants of different autophagy pathway genes(ATG6,ATG10,ATG18a),we revealed that the deficiency of autophagy delayed the ripening of fruit.Compared with wild-type(WT),the production of ethylene was significantly reduced and the accumulation of lycopene was delayed in atg mutants during fruit ripening.We also observed the contents of glucose and fructose were both significantly decreased in atg mutants compared with WT,while the content of organic acids showed the opposite trend.Additionally,the negative regulator of ethylene production,APETALA2a(AP2a),interacted with ATG8 through a specific ATG8-interacting motif(AIM)and could be degraded through the autophagy pathway.These results demonstrate that autophagy plays a critical role in fruit ripening by regulating ethylene production and the accumulation of pigments,sugars and organic acids in tomato.
基金The financial assistance provided by the Centre National de la Recherche Scientifique(CNRS),the University of Lille,the Hautsde-France region,and the CPER“Wavetech”are acknowledgedthe Chinese government for the China Scholarship Council(CSC)fellowship。
文摘A promising way to address environmental problems caused by plastic waste is through its upcycling into renewable energy and resources.With annual production reaching millions of tons,one of the most widely single-use daily plastics,polyethylene terephthalate(PET),has recently been investigated in terms of chemical recycling to reduce its environmental impact and generate renewable fuels.This study introduces an innovative electrochemical method for the specific conversion of PET hydrolysate into highvalue compounds utilizing CoCuO_(x)@MXene/NF catalyst.Our findings revealed that the electrocatalyst was capable of facilitating the conversion of water into hydrogen(H_(2)),while simultaneously oxidizing ethylene glycol(EG),obtained from PET plastic waste hydrolysis,into formate with a high selectivity and lower initial potential compared to water oxidation.Notably,the exceptional performance was attributed to the synergistic interfacial electronic coupling effect between CoCuO_(x)and MXene,which results in a low overpotential(1.24 V@10 mA cm^(-2))and a high yield of formate product(87.6%).In addition,the electrolyzer could be operated using solar energy panel for upcycling of PET to formic acid and hydrogen fuels by using CoCuO_(x)@MXene catalyst.
文摘Kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson cv. Bruno) was used toinvestigate the effects of acetylsalicylic acid (ASA, 1.0 mmol/L, pH 3.5) and ethylene (100 mL/L) treat-ments on changes at endogenous salicylic acid (SA) levels and other senescence-related factors duringfruit ripening and softening at 20 ℃. The level of endogenous SA in ripening fruits declined and a closerelationship was observed between the change at endogenous SA level and the rate of fruit ripening andsoftening. ASA treatment elevated SA level in the fruit, slowed down the increases in lipoxygenase (LOX)and allene oxide synthase (AOS) activities, decreased the O22-. production in the preclimacteric phase andthe early phase of ethylene climacteric rise, maintained the stability of cell membrane, inhibited ethylenebiosynthesis, postponed the onset of the ethylene climacteric, and delayed the process of fruit ripeningand softening. On the contrary, application of ethylene to ripening kiwifruit resulted at a lower SA level, anaccelerated increases in the activities of LOX and AOS and the rate of O22-. production, an elevated relativeelectric conductivity and an advanced onset of ethylene climacteric, and a quicker fruit ripening andsoftening. It is suggested that the effects of ASA on ripening kiwifruit can be attributed to its ability toscavenge O22-. and/or to maintain stability of cell membrane.
文摘Glutaredoxins are small heat-stable oxidoreductases that transfer electrons from glutathione （GSH） to oxi- dized cysteine residues, thereby contributing to protein integrity and regulation. In Arabidopsis thaliana, floral glutare- doxins ROXY1 and ROXY2 and pathogen-induced ROXY19/GRX480 interact with bZIP transcription factors of the TGACG （TGA） motif-binding family. ROXY1, ROXY2, and TGA factors PERIANTHIA, TGA9, and TGA10 play essential roles in floral development. In contrast, ectopically expressed ROXY19/GRX480 negatively regulates expression of jasmonic acid （JA）/ ethylene （ET）-induced defense genes through an unknown mechanism that requires clade II transcription factors TGA2, TGA5, and/or TGA6. Here, we report that at least 17 of the 21 land plant-specific glutaredoxins encoded in the Arabidopsis genome interact with TGA2 in a yeast-two-hybrid system. To investigate their capacity to interfere with the expression of JA/ET-induced genes, we developed a transient expression system. Activation of the ORA59 （OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF-domain protein 59） promoter by transcription factor EIN3 （ETHYLENE INSENSITVE 3） was sup- pressed by co-expressed ROXY19/GRX480. Suppression depended on the L＊＊LL motif in the C-terminus of ROXY19/ GRX480. This putative protein interaction domain was recently described as being essential for the TGA/ROXY interaction. Ten of the 17 tested ROXY proteins suppressed ORA59 promoter activity, which correlated with the presence of the C-terminal ALWL motif, which is essential for ROXY1 function in flower development. ROXY19/GRX480-mediated repres- sion depended on the GSH binding site, suggesting that redox modification of either TGA factors or as yet unknown target proteins is important for the suppression of ORA59 promoter activity.
文摘The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.
文摘Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids,prior to activation by triethylaluminum, in order to increase their activity in ethylene polymerization. BCl3 provided the highest increase in activity. Interestingly, polymerization results showed no substantial modification of polymer properties, which is consistent with that Lewis acid only promotes the creation of new active sites, after activation by TEA, possessing very similar features to the original ones achievable with conventional precatalysts(i.e. without Lewis-acid treatment).
基金This paper was translated from its Chinese version in Chinese Journal of Rice Science.
文摘To elucidate the relationship between ethylene evolution from the grains and the appearance quality of rice, ten different rice genotypes were used to determine the ethylene evolution rate, 1-aminocylopropane-1-carboxylic acid （ACC） concentration in grains during grain filling and the appearance quality of rice, and the effects of chemical regulators on concentrations of ethylene and ACC in the grains during grain filling were also investigated to verify the roles of ethylene in the rice quality formation. The ethylene evolution rates and ACC concentrations in grains during the mid and late grain filling stages were very significantly and positively correlated with chalky kernel percentage and chalkiness. The cultivars with a low ACC concentration in grains exhibited a close amyloplast arrangement and small space between starch granules, whereas those with a high ACC concentration in grains showed a loose arrangement and wide space between the granules. Application of 1 μmol/L ACC to panicles at mid and late grain filling stages significantly loosened amyloplast arrangement and increased chalky kernel percentage, chalky area and chalkiness, and the results were reversed when 1 μmol/L amino-ethoxyvinylglycine, an inhibitor of ACC synthesis enzyme, was applied to panicles. A practice of moderate dry-wet alternate irrigation reduced ethylene evolution and ACC concentration in grains and thereby reduced chalkiness. The results suggested that ethylene and ACC in grains play an important role in the endosperm structure and appearance quality of rice, and the appearance quality would be improved by reducing ethylene evolution and ACC in grains through either variety breeding and selection, or chemical regulations or cultivation techniques.
文摘The oligomerization of ethylene in FCC dry gas over HZSM-5 catalyst with different Si/A12 ratios was studied. The effect of acid density of catalyst on the oligomerization of ethylene was discussed. By increasing the acid density of catalyst, ethylene conversion showed a linear increase, while the yields of olefins decreased when the acid density of catalyst exceeded 0.14mmolNH3/g owing to a promotion of hydrogen transfer reaction. Through comparing the average distance between acid sites on catalyst with kinetic diameters of olefins, it was found that the dimerization of ethylene was not restrained by the sparse distribution of acid sites, while the hydrogen transfer reaction of C3 and C4 olefins was limited. On these bases, a conclusion is proposed that the dimerization of ethylene proceeded via Eley-Rideal mechanism, while the hydrogen transfer reaction of C3 and C4 olefins followed the Langmuir-Hinshelwood mechanism.
基金supported by grants from the 973 Program(2012CB821702)the National Natural Science Foundation of China(21073192,21173223 and 21173220)the Science Foundation of CAS(KJCX2-YW-H20)and of Fujian Province(2009HZ0006-1)
文摘Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn2（dpe）0.5（mna）2] （1） can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn（Ⅱ） and mna ligands is bridged by dpe ligands, while the complex named [Zn4（dpe）4（mna）4] （2） is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C–H…π and π…π interactions. Compound 3 with general formular [Cd2（dpe）0.5（mna）2]·H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd（Ⅱ） and mna ligands are connected with the bridging of dpe ligands.
文摘Synthesis of acetic acid by direct oxidation of ethylene on Pd-H4SiW12O40-based catalysts was studied in a fixed-bed integral reactor and a pulse differential reactor. From the performance of the catalysts with different compositions and configurations, it is proposed that acetic acid is predominantly produced via an intermediate of acetaldehyde. This can be easily confirmed by comparing the product distributions in the integral and the differential reactors. The active sites for acetic acid formation are considered to exist mainly at the boundaries between the H4SiW12O40 and the Pd particles. The Pd-based catalysts reduced by H2/N2 have higher activities than those reduced by hydrazine, as explained by the degree of Pd dispersion obtained from the characteristics of hydrogen chemical adsorption. It was found that the Pd-Se-SiW12/SiO2 catalyst with selenium tetrachloride as a precursor was more active than that with potassium selenite, and that the acetic acid yield can be greatly increased by adding a suitable amount of dichloroethane (C2H4C12/C2H4 mole ratio=0.03) to the reactants.
文摘Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.
基金Supported by Zhejiang Provincial Natural Science Foundation of China( No.2 0 0 0 72 )
文摘The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The statically saturated adsorption capacity is 181 mg/(g resin). Cu(Ⅱ) adsorbed on APAR can be eluted by 1 0-3 0 mol/L HCl. The rate constant is k 298 =5 58×10 -5 s -1 . The adsorption of Cu(Ⅱ) on APAR follows the Freundlich isotherm. The Δ H of the adsorption is 3 91 kJ/mol. The apparent activation energy is E a=21 4 kJ/mol. The coordination molar ratio of APAR to Cu(Ⅱ) is 1/1. It is shown that the nitrogen and the oxygen atoms in the functional group of APAR coordinate to Cu(Ⅱ).
基金the support of the National Natural Sciences Foundation of China(U2003209 and 31871539 to YX)the China Postdoctoral Science Foundation(2021 T140569 and 2020 M673104 to JZ)。
文摘Cotton fiber is a raw material for the global textile industry and fiber quality is essential to its industrial application.Carotenoids are plant secondary metabolites that may serve as dietary components,regulate light harvesting,and scavenge reactive oxygen species.Although carotenoids accumulate predominantly in rapidly elongating cotton fibers,their roles in cotton fiber development remain poorly understood.In this study,a fiber-specific promoter proSCFP was applied to drive the expression of GhOR1Del,a positive regulator of carotenoid accumulation,to upregulate the carotenoid level in cotton fiber in planta.Fiber length,strength,and fineness were increased in proSCFP:GhOR1Del transgenic cotton and abscisic acid(ABA)and ethylene contents were increased in elongating fibers.The ABA downstream regulator GhbZIP27a stimulated the expression of the ethylene synthase gene GhACO3 by binding to its promoter,suggesting that ABA promoted fiber elongation by increasing ethylene production.These findings suggest the involvement of carotenoids and ABA signaling in promoting cotton fiber elongation and provide a strategy for improving cotton fiber quality.
文摘The effects of adding poly （ethylene glycol） （PEG） into polylactic acid/thermoplastic starch blends （PLA/TPS） on the properties were investigated by DSC, SEM and mechanical property-testing. The blends of PLA/TPS blended with increasing content PEG exhibited lower temperature of glass transition （T） and lower temperature of melting （T） as well as higher melt flow index （MFI）, which indicates the plasticization and proeessability of the composites were dramatically improved. The tensile strength, flexural strength and izod impact strength of PLA/TPS （80/20） increased at first and then decreased with increasing content of PEG due to stronger interfacial adhesion. The optimized mechanical property can be obtained for the blend with 3 wt % PEG. The samples containing PEG after soil burial for 5 months showed quicker degradation being accompanied with large weight loss and mechanical properties loss.
基金supported by the National Key Research and Development Program [Grant No.2018YFD1000200]the National Natural Science Foundation of China [Grant Nos.31872941,32072543]+2 种基金the Construction of Beijing Science and Technology Innovation and Service Capacity in Top Subjects [Grant No.CEFFPXM2019_014207_000032]the 111 Project [Grant No.B17043]the Engineering Research Center of Breeding and Propagation of Horticultural Crops,Ministry of Education。
文摘The regulation of apple(Malus domestica)fruit texture during ripening is complex and a fundamental determinant of its commercial quality.In climacteric fruit,ripening-related processes are regulated by ethylene(ET),and jasmonate(JA)is also involved in the ethylene biosynthesis pathway,mainly through the transcription factor MYC2.However,the molecular genetic mechanism for fruit ripening processes between the JA and ET signaling pathways still needs to be elucidated.In order to explore how JA regulates apple fruit ripening through ERF4,we used’Gala’and’Ralls Janet’fruit at different developmental stages as experimental materials to determine the fruit firmness and related gene expression analysis.Meanwhile,we carried out different hormone treatments on’Gala’fruit at ripening stage.Here,we show that ERF4 is a core JA signaling hub protein JASMONATE ZIM-DOMAIN(JAZ)interactor that affects ethylene signaling pathways.During fruit development,ERF4 represses the expression of ACS1 and ACO1 by interacting with JAZ,as well as with the JA-activated transcription factor MYC2.Ripening is promoted in JAZ-suppressed apples.Thus,ERF4 acts as a molecular link between ethylene and JA hormone signals,and the natural variation of the ERF4Ethylene-responsive binding factor-associated amphiphilic repression(EAR)motif decreases repression of ethylene biosynthesis genes.
基金financially supported by the National Natural Science Foundation of China(No.51773122 and No.51933007)the International Scientific and Technological Cooperation Project of Sichuan Province(No.2020YFH0084)
文摘In order to obtain a uniform and effectively toughened poly(lactic acid)film by blending with low content of poly(ethylene octene)(POE)with high elasticity,the tailored interfacial intermolecular interaction and entanglement between the two phases of the PLA/POE blend was innovatively constructed via the facile reactive melt blending process through the reaction of the epoxy/anhydride groups grafted on the POE chains with the end groups of PLA chains(PLA/GPOE-MPOE).It was observed that POE domains were embedded tightly in PLA matrix with a fuzzy interface and abundant interface transition area,and the impact fractured surface of the blend showed an obvious plastic deformation with less occurrence of fibrillation of PLA matrix or interfacial de-bonding.Compared with neat PLA and directly blended PLA/POE blends,the PLA/GPOE-MPOE blend exhibited much higher complex viscosity/storage modulus,much lower tanδvalues in the terminal region,and obvious strain-hardening behavior.The deviation in viscoelastic behavior of PLA/GPOE-MPOE from linear PLA indicated the enhanced molecular entanglement between the long-branched chains,resulting in an enhancement of the stretching ability during biaxial drawing of the blend.Uniform PLA/GPOE-MPOE films with draw ratio as high as 7×7 were obtained through biaxial stretching,which showed much higher tensile strength and the elongation at break than that of neat PLA and PLA/POE film.This work provides a facile method for fabricating toughening PLA films with application potentials.
