A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w...A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.展开更多
LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysi...LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysis was applied to investigating the mixture of transition metal acetates. X-ray powder diffraction and charge–discharge test were adopted to characterize the as-prepared LiNi0.8Co0.1Mn0.1O2. The mixture of transition metal acetates undergoes dehydration and decomposition during heating. All the examined LiNi0.8Co0.1Mn0.1O2 samples have a layered structure with R3 m space group. LiNi0.8Co0.1Mn0.1O2 samples prepared with different lithium sources under different synthesis conditions exhibit very different charge–discharge performances. The sample synthesized via the procedure of sintering at 800 °C after heating lithium carbonate and transition metal acetates at 550 °C achieves a highest capacity of 200.8 m A·h/g and an average capacity of 188.1 mA ·h/g in the first 20 cycles at 0.2C.展开更多
The logarithms of retention factors normalized to a hypothetical pure water eluent(log k w) were determined on a reversed phase high performance liquid chromatography(RP HPLC) column (Li Chrosorb RP 18 column...The logarithms of retention factors normalized to a hypothetical pure water eluent(log k w) were determined on a reversed phase high performance liquid chromatography(RP HPLC) column (Li Chrosorb RP 18 column) for 20 new α\|branched phenylsulfonyl acetates. The atomic charge method was applied to develop quantitative structure retention relationships(QSRRs). Among the available geometric and electronic descriptors, surface area (S), ovality (O), and the charge of carboxyl group(Q OC ) are significant. In the model, the contribution of surface area (S) is the greatest. The molecular mechanism of retention was demonstrated through the model. With the correlation coefficient ( r 2 adj , adjusted for degrees of freedom) of 0.964, the standard error of 0.164 and the F value of 170.39, the model has good predictive capacity.展开更多
Semicarbazones, 1,1-diacetates and acetals are efficiently converted to their corresponding carbonyl compounds using synergistic effect between KBrO3 and MoO3 in refluxing CH3CN-H2O in good to high yields.
A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification. The procedure was tested with the spectra of Δ~2- to Δ^(15)-isomers and...A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification. The procedure was tested with the spectra of Δ~2- to Δ^(15)-isomers and the original double-bond position in these acetates was located unambiguously.展开更多
A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yiel...A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yield,at room temperature,without solvent.The catalyst could be recycled six times without a distinct loss of activity.展开更多
Before proposing an innovative process for the coproduction of ethyl and butyl acetates, the individual syntheses of ethyl acetate and butyl acetate by two different routes were first studied. These syntheses involved...Before proposing an innovative process for the coproduction of ethyl and butyl acetates, the individual syntheses of ethyl acetate and butyl acetate by two different routes were first studied. These syntheses involved the reaction of ethanol or n-butanol with acetic acid or acetic anhydride in the presence of ion exchange resins: Amberlyst 15, Amberlyst 16, Amberlyst 36 and Dowex 50WX8. Kinetic and thermodynamic studies were performed with all resins. The lowest activation energy (Ea) value was obtained with Dowex 50WX8, which was identified as the best-performing resin, able to be reused at least in four runs without regeneration. The presence of water-azeotropes during the synthesis of ethyl acetate makes its purification difficult. A new strategy was adopted here, involving the use of ethanol and acetic anhydride as the starting material. In order to minimize acetic acid as co-product of this reaction, a novel two-step process for the coproduction of ethyl and butyl acetates was developed. The first step involves the production of ethyl acetate and its purification. Butyl acetate was produced in the second step: n-butanol was added to the mixture of acetic acid and the resin remaining after the first-step distillation. This process yields ethyl acetate and butyl acetate at high purity and shows an environmental benefit over the independent syntheses by green metrics calculation and life cycle assessment.展开更多
Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse...Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse model of Parkinson's disease and found that it effectively reduced dopamine neuron injury, neurotransmitter dopamine release, and motor symptoms. These neuroprotective effects of chitosan were related to bacterial metabolites, specifically shortchain fatty acids, and chitosan administration altered intestinal microbial diversity and decreased short-chain fatty acid production in the gut. Furthermore, chitosan effectively reduced damage to the intestinal barrier and the blood–brain barrier. Finally, we demonstrated that chitosan improved intestinal barrier function and alleviated inflammation in both the peripheral nervous system and the central nervous system by reducing acetate levels. Based on these findings, we suggest a molecular mechanism by which chitosan decreases inflammation through reducing acetate levels and repairing the intestinal and blood–brain barriers, thereby alleviating symptoms of Parkinson's disease.展开更多
An iron-catalyzed[4+2]annulation of amidines with α,β-unsaturated ketoxime acetates is described.This strategy employs amidines as CN units and provides a new protocol for the construction of 2,4,6-trisubstituted py...An iron-catalyzed[4+2]annulation of amidines with α,β-unsaturated ketoxime acetates is described.This strategy employs amidines as CN units and provides a new protocol for the construction of 2,4,6-trisubstituted pyrimidines under batch and continuous flow conditions in moderate to good yields,exhibiting good functional group tolerance,scalability and operational simplicity.展开更多
This study was carried out to understand and establish the changes in physicochemical properties of starch extracted from Chinese yam (Dioscorea opposita Thunb.) after acetylation. Yam starch acetates with different d...This study was carried out to understand and establish the changes in physicochemical properties of starch extracted from Chinese yam (Dioscorea opposita Thunb.) after acetylation. Yam starch acetates with different degrees of substitution (DS) were prepared by the reaction of yam starch with glacial acetic acid/acetic anhydride using sulfuric acid as the catalyst. Their formation was confirmed by the presence of the carbonyl signal around 1750 cm?1 in the Fourier transform infrared (FT-IR) spectra. The thermal behavior of the native starch and starch acetate were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results reveal that the starch acetates are more thermally stable than the native starch. The starch esters showed 50% weight loss at temperatures from 328°C to 372°C, while the native starch underwent 50% weight loss at 325°C. The glass transition temperature (T g) of the starch decreased from 273°C to 226°c. The X-ray diffraction (XRD) patterns could be classified as typical of the C-type for yam starch. X-ray diffraction also showed the loss of the ordered C-type starch crystalline structure and the degree of crystallinity of starch decreased from 36.10% to 10.96% with the increasing DS. The scanning electron microscopy (SEM) suggested that the most of the starch granules disintegrated with many visible fragments with the increasing DS.展开更多
ZrOCl2 was found to be an effective Lewis acid catalyst for the solventless chemoselective conversion of aldehydes into geminal-diacetates in high yields at room temperature. Regeneration of the aldehydes from the ace...ZrOCl2 was found to be an effective Lewis acid catalyst for the solventless chemoselective conversion of aldehydes into geminal-diacetates in high yields at room temperature. Regeneration of the aldehydes from the acetals was also achieved using the same catalyst in water. The beneficial effect of microwave irradiation on the reaction was also described. Other advantages are the very low loading of catalyst, high yields achieved even on a gram scale, and considerably shortened reaction time compared to the conventional method.展开更多
The enantioselective allylic amination of Morita-Baylis-Hillman acetates catalyzed by chiral cyclohexane-based thiourea-phosphine catalysts was investigated. In the presence of 20 mol% rosin-derived thiourea-phosphine...The enantioselective allylic amination of Morita-Baylis-Hillman acetates catalyzed by chiral cyclohexane-based thiourea-phosphine catalysts was investigated. In the presence of 20 mol% rosin-derived thiourea-phosphine 3j, the chiral amines were obtained in up to 88% yield and up to 85% ee.展开更多
High-performance MXene-based polymer nanocomposites are well-suited for various industrial applications owing to their excellent mechanical,thermal,and other properties.However,the fabrication of flame-retardant polym...High-performance MXene-based polymer nanocomposites are well-suited for various industrial applications owing to their excellent mechanical,thermal,and other properties.However,the fabrication of flame-retardant polymer/MXene nanocom-posites remains challenging owing to the limited flame-retardant properties of MXene itself.This study prepared a novel MXene@Ag@PA hybrid material via radiation modification and complexation reaction.This material was used to further enhance the key properties of ethylene-vinyl acetate(EVA),such as its mechanical properties,thermal conductivity,flame retardancy,and electromagnetic shielding.The addition of two parts of this hybrid material increased the thermal conduc-tivity of EVA by 44.2%and reduced its peak exothermic rate during combustion by 30.1%compared with pure EVA.The material also significantly reduced smoke production and increased the residue content.In the X-band,the electromagnetic shielding effectiveness of the EVA composites reached 20 dB.Moreover,the MXene@Ag@PA hybrid material could be used to further enhance the mechanical properties of EVA composites under electron-beam irradiation.Thus,this study contributes to the development of MXene-based EVA advanced materials that are fire-safe,have high strength,and exhibit good electromagnetic shielding performance for various applications.展开更多
Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in br...Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in broad-spectrum(UVA and UVB)sunscreens.It could be partially and selectively acetylated in a simple,fast,and more reliable process.In this work,a composite film was prepared with UV-resistant properties through a casting method.Bio-based cellulose acetate(CA)was employed as a major matrix while nano-acetylated kraft lignin(AL-NPs)was used as filler during synthesizing UV-shielding films loaded with various amounts(1–5 wt.%)of AL-NPs.Kraft lignin was acetylated through a simple and fast microwave-assisted process using acetic acid as a solvent and acetylating agent.The physicochemical and morphological characteristics of the prepared films were evaluated using different methods,including scanning electron microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),X-ray diffraction analysis(XRD),mechanical testing and contact angle measurement.The UV-Vis spectroscopy optical investigation of the prepared films revealed that AL-NPs in the CA matrix showed strong UV absorption.This feature demonstrated the effectiveness of our research in developing UV-resistant bio-based polymer films.Hence,the prepared films can be considered as successful candidates to be applied in packaging applications.展开更多
Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of meth...Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet(VUV)lamp initiated CIMS for on-line gaseous formic and acetic acids analysis.In this work,we present a new CIMS based on VUV lamp,and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer electrode.Acetone was added to the photoionization zone,and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I−,and the addition of acetone reduced the amount of methyl iodide by 2/3.In the chemical ionization zone,a headspace vial containing ultrapure water was added for humidity calibration,and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation(R2>0.95).With humidity calibration,the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88%RH.In this mode,limits of detection of 10 and 50 pptv are obtained for formic and acetic acids,respectively.And the relative standard deviation(RSD)of quantitation stability for 6 days were less than 10.5%.This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus(Qingdao,China).In addition,we developed a simple model based formic acid concentration to assess vehicular emissions.展开更多
Background:Chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS)is a frequently encountered disorder characterized by voiding symptoms and pelvic or perineal pain.Proinflammatory T helper 17(Th17)cells are essenti...Background:Chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS)is a frequently encountered disorder characterized by voiding symptoms and pelvic or perineal pain.Proinflammatory T helper 17(Th17)cells are essential for triggering the development of CP/CPPS.High-salt diet(HSD)consumption has been found to cause an accumulation of sodium chloride in peripheral organs,inducing autoimmune responses via the Th17 cell axis.It is currently unknown whether HSD affects the etiology and course of CP/CPPS.Methods:Patients diagnosed with CP/CPPS were evaluated with the National Institutes of Health Chronic Prostatitis Symptom Index scoring system,and the correlation between the symptoms of CP/CPPS with HSD was analyzed.The experimental autoimmune prostatitis(EAP)mouse was established and the mice were fed either a normal-salt diet(NSD)or HSD for 6 weeks to investigate the impact of HSD on CP/CPPS.Then,16S ribosomal RNA sequencing and untargeted metabolomics were introduced to detect the differences in the gut microflora composition and metabolite profiles between NSD-fed and HSD-fed mice,followed by fecal microbiota transplantation,5-hydroxyindole acetic acid(5-HIAA)supplementation,aryl hydrocarbon receptor(AHR)inhibition,and in vitro Th17 differentiation experiments,which were performed to explore the mechanisms underlying HSD-aggravated CP/CPPS.Finally,chromatin immunoprecipitation assay and quantitative polymerase chain reaction were conducted to validate whether AHR can serve as a transcription factor by interacting with the serum and glucocorticoid-regulated kinase 1(Sgk1)promoter in CD4^(+)T cells.Results:Increased salt consumption had a positive correlation with symptom scores of CP/CPPS patients,which was validated by feeding EAP mice with HSD,and HSD worsened the prostate inflammation and tactile allodynia in EAP mice through promoting the differentiation of CD4^(+)T cells to Th17 cells.HSD exacerbated EAP by significantly reducing the relative abundance of beneficial gut microflora,such as Lactobacillaceae,and gut microbiota metabolite 5-HIAA,which is related to tryptophan metabolism.The prostate inflammation,tactile allodynia,and proportion of Th17 cells in mice that received fecal suspensions from the EAP^(+)HSD group were significantly more severe or higher than those in mice that received fecal suspensions from the EAP^(+)NSD group.However,5-HIAA supplementation ameliorated the symptoms of EAP caused by HSD through inhibiting the differentiation of CD4^(+)T cells to Th17 cells,while AHR inhibition abrogated the protective effects of 5-HIAA supplementation on EAP mice fed a HSD through promoting the differentiation of CD4^(+)T cells to Th17 cells.Mechanistically,it has been revealed that the SGK1/forkhead box protein O1(FOXO1)pathway was significantly activated during cytokine-induced Th17 cell differentiation,and AHR has been shown to inhibit SGK1 transcription by interacting with the Sgk1 promoter in CD4^(+)T cells to inhibit FOXO1 phosphorylation,consequently restoring the equilibrium of Th17 cell differentiation.Conclusions:Our findings indicated that high salt intake represented a risk factor for the development of CP/CPPS as it promoted the differentiation of CD4^(+)T cells to Th17 cells through the 5-HIAA/AHR/SGK1/FOXO1 axis,which might be a potential therapeutic target for CP/CPPS.展开更多
The neurotransmitter 5-hydroxytryptamine(5-HT),primarily produced by intestinal enterochromaffin(EC)cells,relies on tryptophan hydroxylase 1(TPH1)for synthesis.Research suggested Bifidobacterium breve CCFM1025’s pote...The neurotransmitter 5-hydroxytryptamine(5-HT),primarily produced by intestinal enterochromaffin(EC)cells,relies on tryptophan hydroxylase 1(TPH1)for synthesis.Research suggested Bifidobacterium breve CCFM1025’s potential in regulating Tph1 gene expression,maintaining 5-HT levels in stressed mice,but its precise mechanisms were unclear.This study used metabolomic techniques to assess probiotic fermentation products,revealing acetate as the crucial element in Bb-CCFM1025’s regulation of gut 5-HT synthesis.Further exploration correlated acetate with Tph1 transcription in intestinal organoids.Transcriptomic methods and quantitative reverse transcription polymerase chain reaction validation demonstrated how acetate facilitated 5-HT synthesis and secretion.It unveiled that acetate orchestrates signaling pathways(phosphoinositide 3-kinase-protein kinase B(PI3K-AKT),phospholipase C-phosphorylated extracellular signal-regulated kinase(PLC-pERK),and PLC-1,4,5-trisphosphate(IP3)-Ca^(2+))within EC,enabling 5-HT production.These findings elucidate the biochemical mechanisms behind specific probiotics’effects,aiding in the targeted selection of similar beneficial strains.This study offers theoretical support for choosing probiotics with analogous functionalities based on their physiological impacts.展开更多
Bio-oil is a renewable fuel that can be obtained from biomass waste,such as empty palm fruit bunches,sugarcane bagasse,and rice husks.Within a biorefinery framework,bio-oil had not met the standards as a fuel due to t...Bio-oil is a renewable fuel that can be obtained from biomass waste,such as empty palm fruit bunches,sugarcane bagasse,and rice husks.Within a biorefinery framework,bio-oil had not met the standards as a fuel due to the presence of impurities like corrosive phenol.Therefore,the separation of phenol from bio-oil is essential and can be achieved using the extraction method.In this study,biomass wastes(empty fruit bunches of oil palm,sugarcane bagasse,and rice husk)were pyrolyzed in a biorefinery framework to produce bio-oil,which was then refined through liquid-liquid extraction with a methanol-chloroform and ethyl acetate solvents to remove its phenolic compound.The extraction with methanol-chloroform solvent was carried out for 1 h at 50℃.Meanwhile,extraction with ethyl acetate solvent was carried out for 3 h at 70℃.Both extractions used the same variations,i.e.,bio-oil:solvent ratio at 1:1,1:2,1:3,and 1:4,and stirring speeds of 150 rpm,200 rpm,250 rpm,and 300 rpm.The bio-oil obtained from this study contained complex chemical compounds and had characteristics such as a pH of 5,a density of 1.116 g/mL,and a viscosity of 29.57 cSt.Theoptimization results using response surface methodology(RSM)showed that the best yield formethanolchloroform was 72.98%at a stirring speed of 250 rpm and a ratio of 1:3.As for ethyl acetate solvent,the highest yield obtained was 71.78%at a stirring speed of 237.145 rpm and a ratio of 1:2.展开更多
Biodegradable plastics are types of plastics that can decompose into water and carbon dioxide the actions of living organisms,mostly by bacteria.Generally,biodegradable plastics are obtained from renewable raw materia...Biodegradable plastics are types of plastics that can decompose into water and carbon dioxide the actions of living organisms,mostly by bacteria.Generally,biodegradable plastics are obtained from renewable raw materials,microorganisms,petrochemicals,or a combination of all three.This study aims to develop an innovative bioplastic by combining chitosan and lignin.Bioplastic was prepared by casting method and characterized by measuring the mechanical properties like tensile strength,Young’smodulus,and elongation at break.The chemical structure,together with the interactions among chitosan and lignin and the presence of new chemical bonds,were evaluated by FTIR,while the thermal properties were assessed by thermogravimetric analysis.The water vapor permeability,tests and transparency as well as biodegradability,were also carried out.The results show a tensile strength value of 34.82 MPa,Young’s modulus of 18.54 MPa,and elongation at a break of 2.74%.Moreover,the interaction between chitosan and lignin affects the intensity of the absorption peak,leading to reduced transparency and increased thermal stability.The chitosan/lignin interactions also influence the crystalline size,making it easier to degrade andmore flexible rather than rigid.The contact angle shows the bioplastic’s ability to resist water absorption for 4minutes.In the biodegradation test,the sample began to degrade after 30 days of soil burial test observation.展开更多
Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study eva...Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.展开更多
文摘A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.
基金Project(2010ZC051)supported by the Natural Science Foundation of Yunnan Province,ChinaProject(20140439)supported by the Analysis and Testing Foundation from Kunming University of Science and Technology,ChinaProject(14118245)supported by the Starting Research Fund from Kunming University of Science and Technology,China
文摘LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysis was applied to investigating the mixture of transition metal acetates. X-ray powder diffraction and charge–discharge test were adopted to characterize the as-prepared LiNi0.8Co0.1Mn0.1O2. The mixture of transition metal acetates undergoes dehydration and decomposition during heating. All the examined LiNi0.8Co0.1Mn0.1O2 samples have a layered structure with R3 m space group. LiNi0.8Co0.1Mn0.1O2 samples prepared with different lithium sources under different synthesis conditions exhibit very different charge–discharge performances. The sample synthesized via the procedure of sintering at 800 °C after heating lithium carbonate and transition metal acetates at 550 °C achieves a highest capacity of 200.8 m A·h/g and an average capacity of 188.1 mA ·h/g in the first 20 cycles at 0.2C.
基金TheNationalNaturalScienceFoundationofChina (No .2 9837180 )
文摘The logarithms of retention factors normalized to a hypothetical pure water eluent(log k w) were determined on a reversed phase high performance liquid chromatography(RP HPLC) column (Li Chrosorb RP 18 column) for 20 new α\|branched phenylsulfonyl acetates. The atomic charge method was applied to develop quantitative structure retention relationships(QSRRs). Among the available geometric and electronic descriptors, surface area (S), ovality (O), and the charge of carboxyl group(Q OC ) are significant. In the model, the contribution of surface area (S) is the greatest. The molecular mechanism of retention was demonstrated through the model. With the correlation coefficient ( r 2 adj , adjusted for degrees of freedom) of 0.964, the standard error of 0.164 and the F value of 170.39, the model has good predictive capacity.
基金The partial support of this work by the University of Guilan Research Council is gratefully acknowledged.
文摘Semicarbazones, 1,1-diacetates and acetals are efficiently converted to their corresponding carbonyl compounds using synergistic effect between KBrO3 and MoO3 in refluxing CH3CN-H2O in good to high yields.
文摘A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification. The procedure was tested with the spectra of Δ~2- to Δ^(15)-isomers and the original double-bond position in these acetates was located unambiguously.
文摘A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yield,at room temperature,without solvent.The catalyst could be recycled six times without a distinct loss of activity.
基金supported by the European Union’s Seventh Framework Program for research,technological development and demonstration(FP7/2007-2013)[Grant Agreement No.605215]CONACyT for providing funding through PhD scholarship no.383910.
文摘Before proposing an innovative process for the coproduction of ethyl and butyl acetates, the individual syntheses of ethyl acetate and butyl acetate by two different routes were first studied. These syntheses involved the reaction of ethanol or n-butanol with acetic acid or acetic anhydride in the presence of ion exchange resins: Amberlyst 15, Amberlyst 16, Amberlyst 36 and Dowex 50WX8. Kinetic and thermodynamic studies were performed with all resins. The lowest activation energy (Ea) value was obtained with Dowex 50WX8, which was identified as the best-performing resin, able to be reused at least in four runs without regeneration. The presence of water-azeotropes during the synthesis of ethyl acetate makes its purification difficult. A new strategy was adopted here, involving the use of ethanol and acetic anhydride as the starting material. In order to minimize acetic acid as co-product of this reaction, a novel two-step process for the coproduction of ethyl and butyl acetates was developed. The first step involves the production of ethyl acetate and its purification. Butyl acetate was produced in the second step: n-butanol was added to the mixture of acetic acid and the resin remaining after the first-step distillation. This process yields ethyl acetate and butyl acetate at high purity and shows an environmental benefit over the independent syntheses by green metrics calculation and life cycle assessment.
基金supported by the National Natural Science Foundation of China,Nos. 32260196 (to JY), 81860646 (to ZY) and 31860274 (to JY)a grant from Yunnan Department of Science and Technology,Nos. 202101AT070251 (to JY), 202201AS070084 (to ZY), 202301AY070001-239 (to JY), 202101AZ070001-012, and 2019FI016 (to ZY)。
文摘Studies have shown that chitosan protects against neurodegenerative diseases. However, the precise mechanism remains poorly understood. In this study, we administered chitosan intragastrically to an MPTP-induced mouse model of Parkinson's disease and found that it effectively reduced dopamine neuron injury, neurotransmitter dopamine release, and motor symptoms. These neuroprotective effects of chitosan were related to bacterial metabolites, specifically shortchain fatty acids, and chitosan administration altered intestinal microbial diversity and decreased short-chain fatty acid production in the gut. Furthermore, chitosan effectively reduced damage to the intestinal barrier and the blood–brain barrier. Finally, we demonstrated that chitosan improved intestinal barrier function and alleviated inflammation in both the peripheral nervous system and the central nervous system by reducing acetate levels. Based on these findings, we suggest a molecular mechanism by which chitosan decreases inflammation through reducing acetate levels and repairing the intestinal and blood–brain barriers, thereby alleviating symptoms of Parkinson's disease.
基金the National Natural Science Foundation of China(No.22078150)the National Key R&D Program of China(No.2021YFC2101904)+1 种基金the Jiangsu Province Industrial Prospects and Key Core Technologies-Competitive Projects(No.BE2021083)the Nanjing International Joint R&D Project(No.202002037)for their financial support。
文摘An iron-catalyzed[4+2]annulation of amidines with α,β-unsaturated ketoxime acetates is described.This strategy employs amidines as CN units and provides a new protocol for the construction of 2,4,6-trisubstituted pyrimidines under batch and continuous flow conditions in moderate to good yields,exhibiting good functional group tolerance,scalability and operational simplicity.
基金the funds for New Century Elite of Education Ministry (Grant No. E105001)the funds from the Tianjin Municipal Science and Technology Commis-sion (Grant No. 07JCZDJC05400)Natural Science Foundation of Tianjin Mu-nicipal (Grant No. 08JCZDJC15300)
文摘This study was carried out to understand and establish the changes in physicochemical properties of starch extracted from Chinese yam (Dioscorea opposita Thunb.) after acetylation. Yam starch acetates with different degrees of substitution (DS) were prepared by the reaction of yam starch with glacial acetic acid/acetic anhydride using sulfuric acid as the catalyst. Their formation was confirmed by the presence of the carbonyl signal around 1750 cm?1 in the Fourier transform infrared (FT-IR) spectra. The thermal behavior of the native starch and starch acetate were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results reveal that the starch acetates are more thermally stable than the native starch. The starch esters showed 50% weight loss at temperatures from 328°C to 372°C, while the native starch underwent 50% weight loss at 325°C. The glass transition temperature (T g) of the starch decreased from 273°C to 226°c. The X-ray diffraction (XRD) patterns could be classified as typical of the C-type for yam starch. X-ray diffraction also showed the loss of the ordered C-type starch crystalline structure and the degree of crystallinity of starch decreased from 36.10% to 10.96% with the increasing DS. The scanning electron microscopy (SEM) suggested that the most of the starch granules disintegrated with many visible fragments with the increasing DS.
文摘ZrOCl2 was found to be an effective Lewis acid catalyst for the solventless chemoselective conversion of aldehydes into geminal-diacetates in high yields at room temperature. Regeneration of the aldehydes from the acetals was also achieved using the same catalyst in water. The beneficial effect of microwave irradiation on the reaction was also described. Other advantages are the very low loading of catalyst, high yields achieved even on a gram scale, and considerably shortened reaction time compared to the conventional method.
基金We are grateful for the financial support from the National Natural Science Foundation of China （Nos. 21242007, 21102043）, Science and Technology Com- mission of Shanghai Municipality （No. 15ZR1409200）, and the Fundamental Research Funds for the Central Universities.
文摘The enantioselective allylic amination of Morita-Baylis-Hillman acetates catalyzed by chiral cyclohexane-based thiourea-phosphine catalysts was investigated. In the presence of 20 mol% rosin-derived thiourea-phosphine 3j, the chiral amines were obtained in up to 88% yield and up to 85% ee.
文摘High-performance MXene-based polymer nanocomposites are well-suited for various industrial applications owing to their excellent mechanical,thermal,and other properties.However,the fabrication of flame-retardant polymer/MXene nanocom-posites remains challenging owing to the limited flame-retardant properties of MXene itself.This study prepared a novel MXene@Ag@PA hybrid material via radiation modification and complexation reaction.This material was used to further enhance the key properties of ethylene-vinyl acetate(EVA),such as its mechanical properties,thermal conductivity,flame retardancy,and electromagnetic shielding.The addition of two parts of this hybrid material increased the thermal conduc-tivity of EVA by 44.2%and reduced its peak exothermic rate during combustion by 30.1%compared with pure EVA.The material also significantly reduced smoke production and increased the residue content.In the X-band,the electromagnetic shielding effectiveness of the EVA composites reached 20 dB.Moreover,the MXene@Ag@PA hybrid material could be used to further enhance the mechanical properties of EVA composites under electron-beam irradiation.Thus,this study contributes to the development of MXene-based EVA advanced materials that are fire-safe,have high strength,and exhibit good electromagnetic shielding performance for various applications.
文摘Developing favorable bio-based polymers that replace petroleum-based plastics is an essential environmental demand.Lignin is a by-product of the chemical pulping industry.It is a natural UV protection ingredient in broad-spectrum(UVA and UVB)sunscreens.It could be partially and selectively acetylated in a simple,fast,and more reliable process.In this work,a composite film was prepared with UV-resistant properties through a casting method.Bio-based cellulose acetate(CA)was employed as a major matrix while nano-acetylated kraft lignin(AL-NPs)was used as filler during synthesizing UV-shielding films loaded with various amounts(1–5 wt.%)of AL-NPs.Kraft lignin was acetylated through a simple and fast microwave-assisted process using acetic acid as a solvent and acetylating agent.The physicochemical and morphological characteristics of the prepared films were evaluated using different methods,including scanning electron microscopy(SEM),Fourier Transform Infrared Spectroscopy(FTIR),X-ray diffraction analysis(XRD),mechanical testing and contact angle measurement.The UV-Vis spectroscopy optical investigation of the prepared films revealed that AL-NPs in the CA matrix showed strong UV absorption.This feature demonstrated the effectiveness of our research in developing UV-resistant bio-based polymer films.Hence,the prepared films can be considered as successful candidates to be applied in packaging applications.
基金supported by the National Special Fund for the Development of Major Research Equipment and Instrument(No.2020YFF01014503)the Young Taishan Scholars(No.tsqn201909039)the College 20 Project fromJi Nan Science&Technology Bureau(No.2021GXRC058).
文摘Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric chemistry.In iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet(VUV)lamp initiated CIMS for on-line gaseous formic and acetic acids analysis.In this work,we present a new CIMS based on VUV lamp,and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer electrode.Acetone was added to the photoionization zone,and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I−,and the addition of acetone reduced the amount of methyl iodide by 2/3.In the chemical ionization zone,a headspace vial containing ultrapure water was added for humidity calibration,and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation(R2>0.95).With humidity calibration,the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88%RH.In this mode,limits of detection of 10 and 50 pptv are obtained for formic and acetic acids,respectively.And the relative standard deviation(RSD)of quantitation stability for 6 days were less than 10.5%.This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus(Qingdao,China).In addition,we developed a simple model based formic acid concentration to assess vehicular emissions.
基金supported by the National Natural Science Foundation of China(82300872 and 82170787)the Anhui Provincial Natural Science Foundation(2408085Y038)+3 种基金the Supporting Projects for Innovative Leading Talents(T000529)the Distinguished Young Scholar of Anhui Colleges(2021-108-10)the Science Foundation for Outstanding Young Scholar of Anhui Colleges(2022AH020073)the Sanming Project of Medicine in Shenzhen Nanshan(SZSM20210300).
文摘Background:Chronic prostatitis/chronic pelvic pain syndrome(CP/CPPS)is a frequently encountered disorder characterized by voiding symptoms and pelvic or perineal pain.Proinflammatory T helper 17(Th17)cells are essential for triggering the development of CP/CPPS.High-salt diet(HSD)consumption has been found to cause an accumulation of sodium chloride in peripheral organs,inducing autoimmune responses via the Th17 cell axis.It is currently unknown whether HSD affects the etiology and course of CP/CPPS.Methods:Patients diagnosed with CP/CPPS were evaluated with the National Institutes of Health Chronic Prostatitis Symptom Index scoring system,and the correlation between the symptoms of CP/CPPS with HSD was analyzed.The experimental autoimmune prostatitis(EAP)mouse was established and the mice were fed either a normal-salt diet(NSD)or HSD for 6 weeks to investigate the impact of HSD on CP/CPPS.Then,16S ribosomal RNA sequencing and untargeted metabolomics were introduced to detect the differences in the gut microflora composition and metabolite profiles between NSD-fed and HSD-fed mice,followed by fecal microbiota transplantation,5-hydroxyindole acetic acid(5-HIAA)supplementation,aryl hydrocarbon receptor(AHR)inhibition,and in vitro Th17 differentiation experiments,which were performed to explore the mechanisms underlying HSD-aggravated CP/CPPS.Finally,chromatin immunoprecipitation assay and quantitative polymerase chain reaction were conducted to validate whether AHR can serve as a transcription factor by interacting with the serum and glucocorticoid-regulated kinase 1(Sgk1)promoter in CD4^(+)T cells.Results:Increased salt consumption had a positive correlation with symptom scores of CP/CPPS patients,which was validated by feeding EAP mice with HSD,and HSD worsened the prostate inflammation and tactile allodynia in EAP mice through promoting the differentiation of CD4^(+)T cells to Th17 cells.HSD exacerbated EAP by significantly reducing the relative abundance of beneficial gut microflora,such as Lactobacillaceae,and gut microbiota metabolite 5-HIAA,which is related to tryptophan metabolism.The prostate inflammation,tactile allodynia,and proportion of Th17 cells in mice that received fecal suspensions from the EAP^(+)HSD group were significantly more severe or higher than those in mice that received fecal suspensions from the EAP^(+)NSD group.However,5-HIAA supplementation ameliorated the symptoms of EAP caused by HSD through inhibiting the differentiation of CD4^(+)T cells to Th17 cells,while AHR inhibition abrogated the protective effects of 5-HIAA supplementation on EAP mice fed a HSD through promoting the differentiation of CD4^(+)T cells to Th17 cells.Mechanistically,it has been revealed that the SGK1/forkhead box protein O1(FOXO1)pathway was significantly activated during cytokine-induced Th17 cell differentiation,and AHR has been shown to inhibit SGK1 transcription by interacting with the Sgk1 promoter in CD4^(+)T cells to inhibit FOXO1 phosphorylation,consequently restoring the equilibrium of Th17 cell differentiation.Conclusions:Our findings indicated that high salt intake represented a risk factor for the development of CP/CPPS as it promoted the differentiation of CD4^(+)T cells to Th17 cells through the 5-HIAA/AHR/SGK1/FOXO1 axis,which might be a potential therapeutic target for CP/CPPS.
基金supported by the National Natural Science Foundation of China(32201988)Natural Science Foundation of Jiangsu Province(BK20210456)+3 种基金Special Fund for Science and Technology Program of Jiangsu Province(BM2022019)the National Key R&D Program of China(2023YFC2506004)the Fundamental Research Funds for the Central Universities(JUSRP123047)the Program of Collaborative Innovation Centre of Food Safety and Quality Control in Jiangsu Province.
文摘The neurotransmitter 5-hydroxytryptamine(5-HT),primarily produced by intestinal enterochromaffin(EC)cells,relies on tryptophan hydroxylase 1(TPH1)for synthesis.Research suggested Bifidobacterium breve CCFM1025’s potential in regulating Tph1 gene expression,maintaining 5-HT levels in stressed mice,but its precise mechanisms were unclear.This study used metabolomic techniques to assess probiotic fermentation products,revealing acetate as the crucial element in Bb-CCFM1025’s regulation of gut 5-HT synthesis.Further exploration correlated acetate with Tph1 transcription in intestinal organoids.Transcriptomic methods and quantitative reverse transcription polymerase chain reaction validation demonstrated how acetate facilitated 5-HT synthesis and secretion.It unveiled that acetate orchestrates signaling pathways(phosphoinositide 3-kinase-protein kinase B(PI3K-AKT),phospholipase C-phosphorylated extracellular signal-regulated kinase(PLC-pERK),and PLC-1,4,5-trisphosphate(IP3)-Ca^(2+))within EC,enabling 5-HT production.These findings elucidate the biochemical mechanisms behind specific probiotics’effects,aiding in the targeted selection of similar beneficial strains.This study offers theoretical support for choosing probiotics with analogous functionalities based on their physiological impacts.
基金supported by theUniversitasNegeri Semarang throughDPAUNNES 2024The grant number is No.271.26.2/UN37/PPK.10/2024.
文摘Bio-oil is a renewable fuel that can be obtained from biomass waste,such as empty palm fruit bunches,sugarcane bagasse,and rice husks.Within a biorefinery framework,bio-oil had not met the standards as a fuel due to the presence of impurities like corrosive phenol.Therefore,the separation of phenol from bio-oil is essential and can be achieved using the extraction method.In this study,biomass wastes(empty fruit bunches of oil palm,sugarcane bagasse,and rice husk)were pyrolyzed in a biorefinery framework to produce bio-oil,which was then refined through liquid-liquid extraction with a methanol-chloroform and ethyl acetate solvents to remove its phenolic compound.The extraction with methanol-chloroform solvent was carried out for 1 h at 50℃.Meanwhile,extraction with ethyl acetate solvent was carried out for 3 h at 70℃.Both extractions used the same variations,i.e.,bio-oil:solvent ratio at 1:1,1:2,1:3,and 1:4,and stirring speeds of 150 rpm,200 rpm,250 rpm,and 300 rpm.The bio-oil obtained from this study contained complex chemical compounds and had characteristics such as a pH of 5,a density of 1.116 g/mL,and a viscosity of 29.57 cSt.Theoptimization results using response surface methodology(RSM)showed that the best yield formethanolchloroform was 72.98%at a stirring speed of 250 rpm and a ratio of 1:3.As for ethyl acetate solvent,the highest yield obtained was 71.78%at a stirring speed of 237.145 rpm and a ratio of 1:2.
基金funded by the joint research collaboration of the Research Organization of Agriculture and Food National Research and Innovation Agency(BRIN)FY 2024(Grant number:6/III.11/HK/2024),with Widya Fatriasari as the Principal Investigator.
文摘Biodegradable plastics are types of plastics that can decompose into water and carbon dioxide the actions of living organisms,mostly by bacteria.Generally,biodegradable plastics are obtained from renewable raw materials,microorganisms,petrochemicals,or a combination of all three.This study aims to develop an innovative bioplastic by combining chitosan and lignin.Bioplastic was prepared by casting method and characterized by measuring the mechanical properties like tensile strength,Young’smodulus,and elongation at break.The chemical structure,together with the interactions among chitosan and lignin and the presence of new chemical bonds,were evaluated by FTIR,while the thermal properties were assessed by thermogravimetric analysis.The water vapor permeability,tests and transparency as well as biodegradability,were also carried out.The results show a tensile strength value of 34.82 MPa,Young’s modulus of 18.54 MPa,and elongation at a break of 2.74%.Moreover,the interaction between chitosan and lignin affects the intensity of the absorption peak,leading to reduced transparency and increased thermal stability.The chitosan/lignin interactions also influence the crystalline size,making it easier to degrade andmore flexible rather than rigid.The contact angle shows the bioplastic’s ability to resist water absorption for 4minutes.In the biodegradation test,the sample began to degrade after 30 days of soil burial test observation.
基金supported by the National Natural Science Foundation of China(Nos.52174239 and 52374259)the Program of China Scholarship Council(No.202406080114)Natural Sciences and Engineering Research Council of Canada(No.NSERC RGPIN 2024-04570).
文摘Chalcopyrite is often intergrown with talc,which,after grinding,forms ultrafine particles(<10μm)that readily coat chalcopyrite surfaces,hindering flotation and causing significant losses in tailings.This study evaluates polyvinyl acetate(PVAc),a thermoplastic polymer,as a selective flocculant to enhance reverse flot ation separation of chalcopyrite from ultrafine talc.Flotation tests showed that at a PVAc dosage of 40 mg/L,talc can be effectively and selectively removed,enabling efficient separation.Laser particle size analysis and scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)confirmed that PVAc promotes selective talc aggregation without affecting chalcopyrite.X-ray photoelectron spectroscopy(XPS)and density functional theory(DFT)calculations revealed that hydrogen bonding between PVAc ester groups and surface hydroxyls on talc drives the flocculation,while chalcopyrite lacks suitable binding sites.PVAc adsorption also enhances talc hydrophobicity.Furthermore,particle-bubble coverage angle measurements and extended Derjaguin-Landau-Verwey-Overbeek(DLVO)theory theoretical calculations demonstrated that PVAc-induced flocculation increases attractive interactions between talc and bubbles,shifting the total interaction energy from repulsive to attractive and promoting bubble-particle attachment.This study clarifies the selective adsorption and flocculation mechanisms of PVAc and reveals the coupling of flocculation and flotation of ultrafine talc from a particle-bubble capture perspective,while expanding the potential of ester-based polymers for ultrafine mineral recovery.
