A new series of compounds, 2-(benzodioxol-2-yl)acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited p...A new series of compounds, 2-(benzodioxol-2-yl)acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited potent human PPARδ agonist activities.展开更多
BACKGROUND: The resection rate of primary liver tumor in China is only about 20%. A lot of patients with moderate and advanced liver tumor may lose the chance of opera- tion. The objective of present research was to s...BACKGROUND: The resection rate of primary liver tumor in China is only about 20%. A lot of patients with moderate and advanced liver tumor may lose the chance of opera- tion. The objective of present research was to study the ef- ficacy of transcatheter arterial chemoembolization (TACE) combined with percutaneous injection of chemical agents and acetic acids in the treatment of patients with primary liver cancer (PLC). METHODS: Thirty-three patients with middle and ad- vanced stage of PLC were divided into two groups: percu- taneous injection of chemical agents and acetic acids (15 patients, group A) and TACE (18 patients, group B). RESULTS: Tumor diameter and serum AFP level reduced to 86.6% and 83.3% in group A, and 55.5% and 40% in group B, respectively. There was significant difference be- tween the two groups ( P < 0 . 0 1 ) . The 1-, 2-, 3-, 4-year survival rates of group A were 96.7%, 86.6%, 51.3%, 33.3%, respectively and in group B were 66.7%, 44.4%, 16.7%, 0%, respectively (P<0.01). CONCLUSION: TACE combined with percutaneous injec- tion of chemical agents and acetic acids is efficacious to in- crease the survival rate of patients with PLC.展开更多
Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough...Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose,D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%–29% over the nano oxide of ceria,zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.展开更多
Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%—97.4%) were obtained when...Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%—97.4%) were obtained when the molar ratio of the reactants was n(ArOH)∶n(NaOH)∶n(ClCH 2CO 2H) =1∶2.5∶1.2 with microwave irradiation power of 640 W for 65—85 s.展开更多
From January 1995 to December 2004, 860 rainwater samples were collected in the humid savannah of Lamto. Using the Henry’s law, we determined the content of formic and acetic acids in the air based on their concentra...From January 1995 to December 2004, 860 rainwater samples were collected in the humid savannah of Lamto. Using the Henry’s law, we determined the content of formic and acetic acids in the air based on their concentrations in rainwater. The annual partial pressure of both formic and acetic acids over the decade is variable. It covers a range of 0.003 (1998) to 0.21 ppbv (1996) and 0.27 (1999) to 0.47 ppbv (1996) for formic and acetic acids respectively. Also, the partial pressure in the dry season is higher than that in the wet season. This difference is related to the enrichment of the organic acid content in the air by the various sources that produce these acids. One of the main sources of increment in organic acid is biomass burning. This biomass burning contributes between 21% and 51% to the formation of the two acids in the humid savannah of Lamto. Ultimately the average annual organic acidity varies from 40% to 60% over the ten years period.展开更多
Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as...Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as two comparative catalysts,Ni/Al_(2)O_(3) and Ni/SiO_(2),with low nickel loading(2%(mass))was conducted to probe involvement of the varied carriers in the steam reforming.The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO_(2) and Ni/Al_(2)O_(3),as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C,resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance.In converse,strong adsorption of aliphatic intermediates over Ni/Al_(2)O_(3) and Ni/SiO_(2) induced serious coking with polymeric coke as the main type(21.5%and 32.1%,respectively),which was significantly higher than that over Ni/biochar(3.9%).The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity.The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam,which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al_(2)O_(3) and Ni/SiO_(2) catalysts.展开更多
Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution...Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in rats.Rats were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical analyses.Results:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced colitis.It also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde levels.Conclusions:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.展开更多
Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environ...Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.展开更多
BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against...BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.展开更多
BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capil...BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capillary network,and gastric pits.AIM To evaluate the effectiveness of a new one-dual(near)focus,NBI mode in the assessment of the microscopic features of gastric body mucosa compared to conventional magnification.METHODS During 2021 and 2022,68 patients underwent proximal gastrointestinal endoscopy using magnification endoscopic modalities subsequently applying acetic acid(AA).The GIF-190HQ series NBI system with dual focus capability was used for the investigation of gastric mucosa.At the time of the endoscopy,the gastric body mucosa of all enrolled patients was photographed using the white light endoscopy(WLE),near focus(NF),NF-NBI,AA-NF,and AA-NF-NBI modes.RESULTS The WLE,NF and NF-NBI endoscopic modes for all patients(204 images)were classified in the same order into three groups.Two images from each patient for the AA-NF and AA-NF-NBI endoscopic modes were classified in the same order.According to all three observers who completed the work independently,NF magnification was significantly superior to WLE(P<0.01),and the NF-NBI mode was significantly superior to NF magnification(P<0.01).After applying AA,the three observers confirmed that AA-NF-NBI was significantly superior to AA-NF(P<0.01).Interobserver kappa values for WLE were 0.609,0.704,and 0.598,respectively and were 0.600,0.721,and 0.637,respectively,for NF magnification.For the NF-NBI mode,the values were 0.378,0.471,and 0.553,respectively.For AA-NF,they were 0.453,0.603,and 0.480,respectively,and for AA-NF-NBI,they were 0.643,0.506,and 0.354,respectively.CONCLUSION When investigating gastric mucosa in microscopic detail,NF-NBI was the most powerful endoscopic mode for assessing regular arrangement of collecting venules,subepithelial capillary network,and gastric pits among the five endoscopic modalities investigated in this study.AA-NF-NBI was the most powerful endoscopic mode for analyzing crypt opening and intervening part.展开更多
It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and co...It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L<sup>-1</sup>) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.展开更多
The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programm...The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.展开更多
The production of formic and acetic acids (or salts) by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and aceti...The production of formic and acetic acids (or salts) by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6% and 11.3% at the reaction condition of 0.5 mol/L NaOH, 120% H2O2 supply and 280 °C. These results will inform studies aiming to develop more environmental friendly lignin conversion processes by obtaining products beyond a CO2 end product.展开更多
BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digest...BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digestive system diseases such as gastric ulcer(GU).However,the mechanism of its potential protective effects against GU remains unclear.AIM To investigate the protective effects of A.japonica on acetic acid-induced GU rats.METHODS The chemical constituents of A.japonica were determined by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)analysis.The rat model of GU was simulated by acetic acid method.The pathological changes of gastric tissues were evaluated by hematoxylin-eosin stain,the levels of epidermal growth factor(EGF),EGF receptor(EGFR),nuclear factor kappa-B(NF-κB),interleukin-1β(IL-1β),IL-10,Na^(+)-K^(+)-ATPase(NKA)in serum and gastric tissues were determined by enzyme-linked immunosorbent assay,and the mRNA expressions of EGFR,NF-κBp65,IkappaBalpha(IκBα)and Zonula Occludens-1(ZO-1)in gastric tissues were determined by real-time reverse transcription polymerase chain reaction,and the efficacy was observed.Then,plasma metabolomic analysis was performed by UPLC-MS/MS to screen the specific potential biomarkers,metabolic pathways and to explore the possible mechani-sms.RESULTS 48 chemical constituents were identified.Many of them have strong pharmacological activity,the results also revealed that A.japonica significantly improved the pathological damage of gastric tissues,increased the expression levels of IL-10,IκBαrelated to anti-inflammatory factors,decreased the expression levels of IL-1β,NF-κB,NF-κBp65,related to proinflammatory factors,restored the levels of factors about EGF,EGFR,ZO-1 associated with ulcer healing and the levels of factors about NKA associated with energy metabolism.Metabolomic analysis identified 10 potential differential metabolites and enriched 7 related metabolic pathways.CONCLUSION These findings contribute to the understanding of the potential mechanism of A.japonica to improve acetic acidinduced GU,and will be of great importance for the development and clinical application of natural drugs related to A.japonica.展开更多
Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet...Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet air oxidation (CWAO) of acetic acid under 230℃ and 5 MPa in a batch reactor. Physical properties including the surface area, crystalline phase, and surface components of the Ru catalysts were characterized by N 2 adsorption, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The CeO 2 -based Ru catalysts had good activity, and the prepared RuO 2 /CeO 2 catalyst showed markedly higher activity than the RuO 2 /CeO 2 -TiO 2 catalyst. The surface structure, the high amount of chemisorbed oxygen on the catalyst surface, and the suitable pH pzc value of the supports played an important role in the activity of the Ru catalysts in CWAO of acetic acid.展开更多
Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scann...Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.展开更多
The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry (AAS), X-ray photoelectron spectrosco...The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and electrochemical polarization measurements. AAS results show that molybdenum is enriched on the surface as the passive film is dissolved. This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons. The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film. XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region. When the polarization potential is much greater than the transpassivation potential, the Mo content accounts for approximately 45% of the metal cations in the nearurface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.展开更多
A synergistic catalytic effect between copper methanesulfonate and acetic acid in tetrahydropyranylation of alcohols and phenol at room temperature under solvent free condition has been described. Both alcohols (prim...A synergistic catalytic effect between copper methanesulfonate and acetic acid in tetrahydropyranylation of alcohols and phenol at room temperature under solvent free condition has been described. Both alcohols (primary, secondary and tertiary) and phenols reacted with 3,4-dihydro-2H-pyran smoothly to afford the corresponding tetrahydropyranyl ethers in good yields.展开更多
In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters wa...In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out.The 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate selectivity.The study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and n-butanol.The 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol reflux.The results are novel.展开更多
The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy (EIS), Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The re...The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy (EIS), Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The results show that the passivation film formed on 316L stainless steel is stable in 60% acetic acid solution from 25 ℃ to 85 ℃. As temperature increased, the polarization resistance decreased but the interface capacitance increased. There was hardly any relation between temperature and the intrinsic property semiconductor. The passivation film represents the p-semiconductor property in the potential interval of -0.5-0.1 V; represents the n-semiconductor property in the potential interval of 0.1-0.9 V; and represents the p-semiconductor property in the potential interval of 0.9-1.1 V. The voltammetry measurements show that the structure of the passivation film is stable when the temperature is lower than 55 ℃ and that its stability decreased when this temperature is exceeded.展开更多
基金supported by the National High Technology Research and Development Program of China(863 project:2003AA235010)the National Natural Science Foundation of China(No.30472092).
文摘A new series of compounds, 2-(benzodioxol-2-yl)acetic acids, have been synthesized. Their structures were confirmed by MS and 1H-NMR. The preliminary pharmacological screening showed that these compounds exhibited potent human PPARδ agonist activities.
文摘BACKGROUND: The resection rate of primary liver tumor in China is only about 20%. A lot of patients with moderate and advanced liver tumor may lose the chance of opera- tion. The objective of present research was to study the ef- ficacy of transcatheter arterial chemoembolization (TACE) combined with percutaneous injection of chemical agents and acetic acids in the treatment of patients with primary liver cancer (PLC). METHODS: Thirty-three patients with middle and ad- vanced stage of PLC were divided into two groups: percu- taneous injection of chemical agents and acetic acids (15 patients, group A) and TACE (18 patients, group B). RESULTS: Tumor diameter and serum AFP level reduced to 86.6% and 83.3% in group A, and 55.5% and 40% in group B, respectively. There was significant difference be- tween the two groups ( P < 0 . 0 1 ) . The 1-, 2-, 3-, 4-year survival rates of group A were 96.7%, 86.6%, 51.3%, 33.3%, respectively and in group B were 66.7%, 44.4%, 16.7%, 0%, respectively (P<0.01). CONCLUSION: TACE combined with percutaneous injec- tion of chemical agents and acetic acids is efficacious to in- crease the survival rate of patients with PLC.
基金supported by the Doctoral Fund of the Ministry of Education of China(Grant No.20100091120035)NSF of China(21103087)
文摘Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose,D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%–29% over the nano oxide of ceria,zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.
文摘Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%—97.4%) were obtained when the molar ratio of the reactants was n(ArOH)∶n(NaOH)∶n(ClCH 2CO 2H) =1∶2.5∶1.2 with microwave irradiation power of 640 W for 65—85 s.
文摘From January 1995 to December 2004, 860 rainwater samples were collected in the humid savannah of Lamto. Using the Henry’s law, we determined the content of formic and acetic acids in the air based on their concentrations in rainwater. The annual partial pressure of both formic and acetic acids over the decade is variable. It covers a range of 0.003 (1998) to 0.21 ppbv (1996) and 0.27 (1999) to 0.47 ppbv (1996) for formic and acetic acids respectively. Also, the partial pressure in the dry season is higher than that in the wet season. This difference is related to the enrichment of the organic acid content in the air by the various sources that produce these acids. One of the main sources of increment in organic acid is biomass burning. This biomass burning contributes between 21% and 51% to the formation of the two acids in the humid savannah of Lamto. Ultimately the average annual organic acidity varies from 40% to 60% over the ten years period.
基金supported by National Natural Science Foundation of China(51876080)the Program for Taishan Scholars of Shandong Province Government,the Agricultural Innovation Program of Shandong Province(SD2019NJ015)+1 种基金the Research and Development program of Shandong Basan Graphite New Material Plant,National Natural Science Foundation of China(52076097)Key projects for inter-governmental cooperation in international science,technology and innovation(2018YFE0127500).
文摘Biochar is a reactive carrier as it may be partially gasified with steam in steam reforming,which could influence the formation of reaction intermediates and modify catalytic behaviors.Herein,the Ni/biochar as well as two comparative catalysts,Ni/Al_(2)O_(3) and Ni/SiO_(2),with low nickel loading(2%(mass))was conducted to probe involvement of the varied carriers in the steam reforming.The results indicated that the Ni/biochar performed excellent catalytic activity than Ni/SiO_(2) and Ni/Al_(2)O_(3),as the biochar carrier facilitated quick conversion of the -OH from dissociation of steam to gasify the oxygen-rich carbonaceous intermediates like C=O and C-O-C,resulting in low coverage while high exposure of nickel species for maintaining the superior catalytic performance.In converse,strong adsorption of aliphatic intermediates over Ni/Al_(2)O_(3) and Ni/SiO_(2) induced serious coking with polymeric coke as the main type(21.5%and 32.1%,respectively),which was significantly higher than that over Ni/biochar(3.9%).The coke over Ni/biochar was mainly aromatic or catalytic type with nanotube morphology and high crystallinity.The high resistivity of Ni/biochar towards coking was due to the balance between formation of coke and gasification of coke and partially biochar with steam,which created developed mesopores in spent Ni/biochar while the coke blocked pores in Ni/Al_(2)O_(3) and Ni/SiO_(2) catalysts.
文摘Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis rats.Methods:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in rats.Rats were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical analyses.Results:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced colitis.It also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde levels.Conclusions:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.
基金the China Scholarship Council(CSC)for funding(no.201806310116)。
文摘Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and cost-effectiveness.However,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low utilization.Thus,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is reported.The resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid addition.The thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.
文摘BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.
文摘BACKGROUND Conventional magnifying endoscopy with narrow-band imaging(NBI)observation of the gastric body mucosa shows dominant patterns in relation to the regular arrangement of collecting venules,subepithelial capillary network,and gastric pits.AIM To evaluate the effectiveness of a new one-dual(near)focus,NBI mode in the assessment of the microscopic features of gastric body mucosa compared to conventional magnification.METHODS During 2021 and 2022,68 patients underwent proximal gastrointestinal endoscopy using magnification endoscopic modalities subsequently applying acetic acid(AA).The GIF-190HQ series NBI system with dual focus capability was used for the investigation of gastric mucosa.At the time of the endoscopy,the gastric body mucosa of all enrolled patients was photographed using the white light endoscopy(WLE),near focus(NF),NF-NBI,AA-NF,and AA-NF-NBI modes.RESULTS The WLE,NF and NF-NBI endoscopic modes for all patients(204 images)were classified in the same order into three groups.Two images from each patient for the AA-NF and AA-NF-NBI endoscopic modes were classified in the same order.According to all three observers who completed the work independently,NF magnification was significantly superior to WLE(P<0.01),and the NF-NBI mode was significantly superior to NF magnification(P<0.01).After applying AA,the three observers confirmed that AA-NF-NBI was significantly superior to AA-NF(P<0.01).Interobserver kappa values for WLE were 0.609,0.704,and 0.598,respectively and were 0.600,0.721,and 0.637,respectively,for NF magnification.For the NF-NBI mode,the values were 0.378,0.471,and 0.553,respectively.For AA-NF,they were 0.453,0.603,and 0.480,respectively,and for AA-NF-NBI,they were 0.643,0.506,and 0.354,respectively.CONCLUSION When investigating gastric mucosa in microscopic detail,NF-NBI was the most powerful endoscopic mode for assessing regular arrangement of collecting venules,subepithelial capillary network,and gastric pits among the five endoscopic modalities investigated in this study.AA-NF-NBI was the most powerful endoscopic mode for analyzing crypt opening and intervening part.
文摘It was reported that hemispheric corrosion occurred in copper tubes in an acetic acid environment. When hemispheric corrosion occurred, corrosion could easily progress if water then flowed into the copper pipe, and countermeasures were needed. Therefore, we studied the copper corrosion caused by acetic acid. The present work investigated the relationship between the corrosion form of copper and acetic acid concentration using phosphorous-deoxidized copper, and reported that hemispherical corrosion was observed at acetic acid concentrations of 0.01 to 1 vol.% (0.002 to 0.2 mol·L<sup>-1</sup>) in the immersion test. In this study, the effects of acetic acid and phosphate on copper corrosion were examined using oxygen-free copper in immersion tests. The results suggested that different concentrations of phosphate in acetic acid solutions and the presence or absence of acetic acid and phosphate affected the corrosion of copper, resulting in different corrosion forms and corrosion progress.
文摘The supported Pt catalysts(1 wt%)were prepared by the incipient impregnation method and analyzed using synchrotron-based X-ray diffraction,BET surface area,oxygen adsorption,CO pulse chemisorption,temperature-programmed desorption(TPD)of acetic acid,H2-TPD,NH3-TPD,O2-TPD,and H2-TPR.The reactivity of Pt-based catalysts was studied using a fixed bed reactor at 300 C and 4 MPa for hydrodeoxygenation of acetic acid,where Pt/TiO2 was very selective for ethane production.TPD experiments revealed that several conditions must be satisfied to achieve this high selectivity to ethane from acetic acid,such as Pt sites,moderate acidity,and medium metal-oxygen bond strength in the oxide support.This work provides insights in developing novel catalytic materials for hydrocarbon productions from various organics including bio-fuels.
基金Project supported by the National Natural Science Foundations of China (Nos. 20976139 and 20777054)the National Key Technology R&D Programs of China (Nos. 2009BAC62B02, 2009AA05Z405, and 2009AA063903)+1 种基金the State Key Laboratory of Pollution Control and Resource Reuse (No. PCRRK08002)the Projects of Shanghai Science and Technology Commission of China (Nos. 09160707900 and 09JC1413900), China
文摘The production of formic and acetic acids (or salts) by hydrothermal oxidation of syringol, a model compound for lignin, was investigated using a batch reactor. Results show that the highest yields of formic and acetic acids were, respectively, 59.6% and 11.3% at the reaction condition of 0.5 mol/L NaOH, 120% H2O2 supply and 280 °C. These results will inform studies aiming to develop more environmental friendly lignin conversion processes by obtaining products beyond a CO2 end product.
基金Supported by National Natural Science Foundation of China,No.81973478Liaoning Revitalization Talents Program,China,No.XLYC2002004Natural Science Foundation of Liaoning Province,China,No.2019-ZD-0443.
文摘BACKGROUND Atractylodes japonica Koidz.ex Kitam.(A.japonica,Chinese name:Guan-Cangzhu,Japanese name:Byaku-jutsu),a perennial herb,which is mainly distributed in northeast area of China,it’s often used to treat digestive system diseases such as gastric ulcer(GU).However,the mechanism of its potential protective effects against GU remains unclear.AIM To investigate the protective effects of A.japonica on acetic acid-induced GU rats.METHODS The chemical constituents of A.japonica were determined by ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS)analysis.The rat model of GU was simulated by acetic acid method.The pathological changes of gastric tissues were evaluated by hematoxylin-eosin stain,the levels of epidermal growth factor(EGF),EGF receptor(EGFR),nuclear factor kappa-B(NF-κB),interleukin-1β(IL-1β),IL-10,Na^(+)-K^(+)-ATPase(NKA)in serum and gastric tissues were determined by enzyme-linked immunosorbent assay,and the mRNA expressions of EGFR,NF-κBp65,IkappaBalpha(IκBα)and Zonula Occludens-1(ZO-1)in gastric tissues were determined by real-time reverse transcription polymerase chain reaction,and the efficacy was observed.Then,plasma metabolomic analysis was performed by UPLC-MS/MS to screen the specific potential biomarkers,metabolic pathways and to explore the possible mechani-sms.RESULTS 48 chemical constituents were identified.Many of them have strong pharmacological activity,the results also revealed that A.japonica significantly improved the pathological damage of gastric tissues,increased the expression levels of IL-10,IκBαrelated to anti-inflammatory factors,decreased the expression levels of IL-1β,NF-κB,NF-κBp65,related to proinflammatory factors,restored the levels of factors about EGF,EGFR,ZO-1 associated with ulcer healing and the levels of factors about NKA associated with energy metabolism.Metabolomic analysis identified 10 potential differential metabolites and enriched 7 related metabolic pathways.CONCLUSION These findings contribute to the understanding of the potential mechanism of A.japonica to improve acetic acidinduced GU,and will be of great importance for the development and clinical application of natural drugs related to A.japonica.
基金supported by the National Natural Science Foundation of China (No. 51078143)the National High Technology Research & Development Program of China (No. 2002AA601260)
文摘Ru catalysts, supported on TiO 2 , CeO 2 , and CeO 2 -TiO 2 , were prepared by the impregnation method. The effect of the structure of the supports on the activity of Ru catalysts was investigated in the catalytic wet air oxidation (CWAO) of acetic acid under 230℃ and 5 MPa in a batch reactor. Physical properties including the surface area, crystalline phase, and surface components of the Ru catalysts were characterized by N 2 adsorption, X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The CeO 2 -based Ru catalysts had good activity, and the prepared RuO 2 /CeO 2 catalyst showed markedly higher activity than the RuO 2 /CeO 2 -TiO 2 catalyst. The surface structure, the high amount of chemisorbed oxygen on the catalyst surface, and the suitable pH pzc value of the supports played an important role in the activity of the Ru catalysts in CWAO of acetic acid.
文摘Nano cerium oxide films were applied on AA7020-T6 aluminum alloy and the effects of acetic acid concentration on the microstructure and electrochemical properties of the coated samples were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and potentiodynamic polarization methods. It has been found that by increasing the acetic acid/CeCl3·7H2O molar ratio, high uniform and crack-free films with well-developed grains were obtained and grain sizes of the films decreased. Elimination of cracks and decreasing grain size of the nano cerium oxide films caused corrosion resistance to increase.
基金the National Natural Science Foundation of China (No.50871020)
文摘The properties of the passive film formed on 2205 stainless steel in acetic acid at high temperature that contained chloride ions were studied by atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and electrochemical polarization measurements. AAS results show that molybdenum is enriched on the surface as the passive film is dissolved. This enrichment decreases the corrosion resistance because it hinders chloride adsorption and Fe ion dissolution, and acts as a local pH buffer because it consumes protons. The dissolution ratio of Fe/Cr is approximately 10 during the active dissolution of the passive film. XPS results indicate that when the potential is in the passivation region, Cr comprises about 50% of the metal cations in the near-surface region of the passive film and is the main metal constituent in this region. When the polarization potential is much greater than the transpassivation potential, the Mo content accounts for approximately 45% of the metal cations in the nearurface region; Fe and Ni have no obvious influence on the formation, dissolution, or puncture of the passive film.
文摘A synergistic catalytic effect between copper methanesulfonate and acetic acid in tetrahydropyranylation of alcohols and phenol at room temperature under solvent free condition has been described. Both alcohols (primary, secondary and tertiary) and phenols reacted with 3,4-dihydro-2H-pyran smoothly to afford the corresponding tetrahydropyranyl ethers in good yields.
文摘In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid (DTPA) supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out.The 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate selectivity.The study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and n-butanol.The 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol reflux.The results are novel.
基金the National R&D Infrastructure and Facility Development Program of China(No.2005DKA10400)
文摘The properties of the passivation film formed on 316L stainless steel were studied by Electrochemical Impedance Spectroscopy (EIS), Mott-Schottky and Voltammetry measurements in high- temperature acetic acid. The results show that the passivation film formed on 316L stainless steel is stable in 60% acetic acid solution from 25 ℃ to 85 ℃. As temperature increased, the polarization resistance decreased but the interface capacitance increased. There was hardly any relation between temperature and the intrinsic property semiconductor. The passivation film represents the p-semiconductor property in the potential interval of -0.5-0.1 V; represents the n-semiconductor property in the potential interval of 0.1-0.9 V; and represents the p-semiconductor property in the potential interval of 0.9-1.1 V. The voltammetry measurements show that the structure of the passivation film is stable when the temperature is lower than 55 ℃ and that its stability decreased when this temperature is exceeded.