Isoimperatorin alleviates acetic acid-induced colitis in rats

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.

Steam reforming of acetic acid over Ni/biochar of low metal-loading:Involvement of biochar in tailoring reaction intermediates renders superior catalytic performance

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.

Acetic acid additive in NaNO_(3)aqueous electrolyte for long-lifespan Mg-air batteries

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.

Could near focus endoscopy,narrow-band imaging,and acetic acid improve the visualization of microscopic features of stomach mucosa?

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.

Gossypol acetic acid regulates leukemia stem cells by degrading LRPPRC via inhibiting IL-6/JAK1/STAT3 signaling or resulting mitochondrial dysfunction

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.

Study of the Effect of Acetic Acid and Phosphate on Copper Corrosion by Immersion Tests

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-1) 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.

Efficacy and safety of intravenous tranexamic acid in total shoulder arthroplasty:A meta-analysis

BACKGROUND Total shoulder arthroplasty(TSA)results in a large amount of perioperative blood loss due to severe trauma.AIM To investigate the safety and efficacy of intravenous tranexamic acid(TXA)in TSA.METHODS We searched the PubMed,Cochrane Library,Embase and Web of Science databases for randomized controlled trials(RCTs)on the use of TXA in TSA.And all the results were checked and assessed by Reference Citation Analysis(https://www.referencecitationanalysis.com/).A meta-analysis was performed with Review Manager 5.3 to calculate the odds ratio(OR)or weighted mean difference(WMD)of related outcome indicators.RESULTS A total of 5 RCTs with level 1 evidence were included.There were 369 cases,with 186 in the TXA group and 183 in the placebo group.The meta-analysis showed that TXA can significantly reduce total blood loss during the perioperative period[WMD=-249.56,95%confidence interval(CI):-347.6 to-151.52,P<0.0001],and the incidence of adverse reactions was low(OR=0.36,95%CI:0.16-0.83,P=0.02).Compared with the placebo group,the TXA group had significantly less total haemoglobin loss(WMD=-34.39,95%CI:-50.56 to-18.22),less haemoglobin fluctuation before and after the operation(WMD=-0.6,95%CI:-0.93 to-0.27)and less 24-h drain output(WMD=-136.87,95%CI:-165.87 to-106.49).There were no significant differences in the operation time(P=0.11)or hospital length of stay(P=0.30)between the two groups.CONCLUSION The application of intravenous TXA in the perioperative period of TSA can significantly reduce the total volume of perioperative blood loss and reduce the incidence of adverse reactions,so TXA is worthy of widespread clinical use.

Chemical components and protective effects of Atractylodes japonica Koidz.ex Kitam against acetic acid-induced gastric ulcer in rats

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.

Evaluation of the diagnostic value of total bile acids/platelets in HBV related liver fibrosis

Objective:Explore the diagnostic value of total bile acids/platelets in HBV related liver fibrosis.Methods:160 patients with chronic HBV infection admitted to the Infection Department of the First Affiliated Hospital of Hainan Medical College from February 2021 to December 2022 were selected.They were divided into two groups based on the degree of liver fibrosis detected by liver biopsy:significant liver fibrosis group and non-significant liver fibrosis group.The total bile acid/blood platelet levels and their correlation with liver fibrosis in the two groups were compared and observed,and the efficacy of other non-invasive liver fibrosis diagnostic models was evaluated.Results:(1)Compared with the non-significant liver fibrosis group,the significant liver fibrosis group showed an increase in total bile acid levels,a decrease in platelet levels,and a significant increase in total bile acid/platelet levels(P<0.05).(2)Platelets decrease with the increase of liver fibrosis degree,total bile acids increase with the increase of liver fibrosis degree,and total bile acids/platelets increase with the increase of liver fibrosis degree.(3)The area under the curve(AUC)of total bile acid/platelet,APRI,FIB-4,and elastography in diagnosing the degree of liver fibrosis were 0.69,0.57,0.56,and 0.68,respectively.Conclusions:The diagnostic efficacy of total bile acids/platelets in diagnosing HBV related liver fibrosis is no less than that of other liver fibrosis diagnostic methods,and it is non-invasive,simple,and convenient,which is worthy of further clinical promotion and validation.

Formation mechanisms of ethyl acetate and organic acids in Kluyveromyces marxianus L1-1 in Chinese acid rice soup

This study aims to explore the formation mechanism of ethyl acetate and organic acids in acid rice soup(rice-acid soup)inoculated with Kluyveromyces marxianus L1-1 through the complementary analysis of transcriptome and proteome.The quantity of K.marxianus L1-1 varied significantly in the fermentation process of rice-acid soup and the first and third days were the two key turning points in the growth phase of K.marxianus L1-1.Importantly,the concentrations of ethyl acetate,ethanol,acetic acid,and L-lactic acid increased from day 1 to day 3.At least 4231 genes and 2937 proteins were identified and 610 differentially expressed proteins were annotated to 30 Kyoto Encyclopedia of Genes and Genomes(KEGG)pathways based on the analysis results of transcriptome and proteome.The key genes and proteins including up-regulated alcohol dehydrogenase family,alcohol O-acetyltransferase,acetyl-CoA C-acetyltransferase,acyl-coenzyme A thioester hydrolase,and down-regulated aldehyde dehydrogenase family were involved in glycolysis/gluconeogenesis pathways,starch and sucrose metabolism pathways,amino sugar and nucleotide sugar metabolism pathways,tricarboxylic acid(TCA)cycle,and pyruvate metabolism pathways,thus promoting the formation of ethyl acetate,organic acids,alcohols,and other esters.Our results revealed the formation mechanisms of ethyl acetate and organic acids in rice-acid soup inoculated with K.marxianus L1-1.

Relationship of nocturnal concentrations of melatonin, gamma-aminobutyric acid and total antioxidants in peripheral blood with insomnia after stroke： study protocol for a prospective non-randomized controlled trial

Melatonin and gamma-aminobutyric acid（GABA） have been shown to regulate sleep. The nocturnal concentrations of melatonin, GABA and total antioxidants may relate to insomnia in stroke patients. In this prospective single-center non-randomized controlled clinical trial performed in the China Rehabilitation Research Center, we analyzed the relationship of nocturnal concentrations of melatonin, GABA and total antioxidants with insomnia after stroke. Patients during rehabilitation of stroke were recruited and assigned to the insomnia group or non-insomnia group. Simultaneously, persons without stroke or insomnia served as normal controls. Each group contained 25 cases. The primary outcome was nocturnal concentrations of melatonin, GABA and total antioxidants in peripheral blood. The secondary outcomes were Pittsburgh Sleep Quality Index, Insomnia Severity Index, Epworth Sleepiness Scale, Fatigue Severity Scale, Morningness-Eveningness Questionnaire（Chinese version）, and National Institute of Health Stroke Scale. The relationship of nocturnal concentrations of melatonin, GABA and total antioxidants with insomnia after stroke was analyzed and showed that they were lower in the insomnia group than in the non-insomnia group. The severity of stroke was higher in the insomnia group than in the non-insomnia group. Correlation analysis demonstrated that the nocturnal concentrations of melatonin and GABA were associated with insomnia after stroke. This trial was registered at Clinical Trials.gov, identifier： NCT03202121.

Effect of lactic acid bacteria and propionic acid on conservation characteristics,aerobic stability and in vitro gas production kinetics and digestibility of whole-crop corn based total mixed ration silage

This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn based totalmixed ration （TMR） silage. Total mixed ration was ensiled with four treatments： （1） no additives （control）; （2） an inoculant （Lactobacillus plantarum） （L）; （3） propionicacid （P）; （4） propionic acid＋lactic acid bacteria （PL）. All treatments were ensiled in laboratory-scale silos for 45 days, and then subjected to an aerobic stability test for12 days. Further, four TMR silages were incubated in vitro with buffered rumen fluid to study in vitro gas production kinetics and digestibility. The results indicated that all TMR silages had good fermentation characteristics with low pH （〈3.80） and ammonia nitrogen （NH3-N） contents, and high lactic acid contents as well as Flieg points. Addition of L further improved TMR silage quality with more lactic acid production. Addition of P and PL decreased lactic acid and NH3-N contents of TMR silage compared to the control （P〈0.05）. After 12 days aerobic exposure, P and PL silages remained stable, but L and the control silages deteriorated as indicated by a reduction in lactic acid and an increase in pH, and numbers of yeast. Compared to the control, addition of L had no effects on TMR silage in terms of 72 h cumulative gas production, in vitro dry matter digestibility, metabolizable energy, net energy for lactation and short chain fatty acids, whereas addition of PL significantly （P〈0.05） increased them. L silage had higher （P〈0.05） in vitro neutral detergent fiber digestibility than the control silage. The results of our study suggested that TMR silage prepared with whole-crop corn can be well preserved with or without additives. Furthermore, the findings of this study suggested that propionic acid is compatible with lactic acid bacteria inoculants, and when used together, although they reduced lactic acid production of TMR silage, they improved aerobic stability and in vitro nutrients digestibility of TMR silage.

Chromoendoscopy of gastric adenoma using an acetic acid indigocarmine mixture

AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy.

Influence of the structure of TiO_2 , CeO_2 , and CeO_2-TiO_2 supports on the activity of Ru catalysts in the catalytic wet air oxidation of acetic acid

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.

Short term effect of Salvia miltiorrhiza in treating rat acetic acid chronic gastric ulcer and long term effect in preventing recurrence

AIM To study the short term effect of Danshen ( Salvia miltiorrhiza ) on acetic acid induced chronic gastric ulcer in rats and its long term effect in preventing recurrence. METHODS Rats with acetic acid induced gastric ulcer were treated with Danshen and cimetidine for 30 days. Traditional gastric mucosal auto radiography and 3H TdR incorporation into gastric mucosa in vitro were employed to study the effects of Danshen in rat acetic acid induced chronic gastric ulcer, including ulcer index (UI), ulcer inhibitory rate (IR) and label rate (LR). RESULTS On the day 5, 30 and 126 of ulcer making, the UI in the Danshen group was obviously lower than that in the cimetidine group and the control group (42 3±3 9, 3 6±1 2, 4 4±2 3; 49 1±3 6, 5 9±1 4, 9 2±1 3; 61 0±3 8, 8 9±2 5, 12 4±2 4, respectively, P <0 01), the IR (%) in the Danshen group was obviously higher than that in the cimetidine group (31, 59, 64 8; 19, 33, 26, respectively), and the LR in the Danshen group was obviously higher than that in the cimetidine group and the control group (10 0±0 5, 16 2±0 8, 15 0±0 6; 9 0±0 5, 13 9±0 6, 10 8±0 7; 6 5±0 7, 10 1±0 5, 8 0±0 7, respectively, P <0 01). There was no obvious difference in UI in the Danshen group on day 30 as compared with that on day 126. CONCLUSION Danshen is effective in promoting ulcer healing and preventing recurrence. The mechanism of action is to strengthen the gastric mucosal barrier and to promote the gastric mucosal cell proliferation along the edge of the ulcer.

Synthesis of ethyl acetate by esterification of acetic acid with ethanol over a heteropolyacid on montmorillonite K10

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.

Copper methanesulfonate-acetic acid as a novel catalytic system for tetrahydropyranylation of alcohols and phenols

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.

Preparation and shaping of solid acid SO_4^(2-)/TiO_2 and its application for esterification of propylene glycol monomethyl ether and acetic acid

The solid acid SO_4^(2-)/TiO_2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate(PMA) through esterification reaction of propylene glycol monomethyl ether(PM)and acetic acid(HAc). The optimal catalyst preparation condition was determined by orthogonal analysis of parameters in a five-factor and four-level test. The obtained solid acid catalysts were characterized in detail by means of X-ray powder diffraction, thermogravimetry, pyridine adsorbed IR analysis, scanning electron microscopy, and BET surface area method. Synthesis of PMA was studied in this paper through experimental investigation of reaction conditions such as temperature, molar ratio of reactants, catalyst dosage and agitation speed. Based on its possible reaction mechanism, a pseudo-homogeneous kinetic model was established and its activation energies E_a^+ and E_a^-,65.68 × 10~3J·mol^(-1) and 57.78 × 10~3J·mol^(-1), were estimated. To prepare shaped solid acid catalyst SO_4^(2-)/TiO_2, the shaping method of impregnation–shaping–impregnation was applied. The optimal molding formulation of solid acid catalyst, obtained from the orthogonal test, was found to be binder 7 wt%, reinforcing agent 20 wt%, pore forming material 2.5 wt%, and lubricant 4 wt%.The results of performance test of catalyst demonstrated that the shaped solid acid catalyst exhibited high activity and stability.

Effects of acetic acid on microstructure and electrochemical properties of nano cerium oxide films coated on AA7020-T6 aluminum alloy

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.

Study on the passive film formed on 2205 stainless steel in acetic acid by AAS and XPS

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.