Black TiO_2(B)/anatase bicrystalline TiO_(2-x) nanofibers with enhanced photocatalytic performance

Black TiO2（B）/anatase bicrystalline TiO2-x nanofibers were synthesized from a porous titanate derivative by calcination in H2, and were characterized using field-emission scanning electron microscopy, Raman spectroscopy, N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet-visible diffuse reflection spectroscopy and photoluminescence measurements. Characterization results showed that no Ti3＋ was present on the surface of black bicrystalline TiO2-x and oxygen vacancies were distributed in the bulk of both TiO2（B） and anatase phases. The O/Ti atom stoichiometric ratio of black bicrystalline TiO2-x was estimated to be 1.97 from the difference of mass loss between black bicrystalline TiO2-x and white bicrystalline TiO2 without oxygen vacancies. The photocatalytic activity of black bicrystalline TiO2-x was 4.2 times higher than that of white bicrystalline TiO2 and 10.5 times higher than that of anatase TiOz. The high photocatalytic activity of black bicrystalline TiO2-x was attributed to its effective separation of electrons and holes, which may be related to the effects of both bicrystalline structure and oxygen vacancies. Black bicrystalline TiO2-x also exhibited good photocatalytic activity after recycling ten times. The black bicrystalline TiO2-x nanofibers show potential for use in environmental and energy applications.

Oxidative leaching behavior of metalliferous black shale in acidic solution using persulfate as oxidant

The oxidative dissolution of metalliferous black shale in sulfuric acid solution using sodium persulfate as an oxidant was investigated. The effects of leaching factors including leaching temperature, leaching time, stirring speed, initial concentration of sodium persulfate and sulfuric acid and particle size on the leaching rate were studied as well. The leaching kinetics of molybdenum, nickel and iron from metalliferous black shale shows that the leaching rate is controlled by a chemical reaction through a layer on the unreacted shrinking core. The leaching process follows the kinetics model 1-（1-a）^1/3=kt with apparent activation energies of 34.50, 43.14 and 71.79 kJ/mol for Mo, Ni and Fe, respectively. The reaction orders in sodium persulfate are 0.80, 1.01 and 0.75 for molybdenum, nickel and iron, respectively, while in sulfuric acid, these orders are 0.45, 0.75 and 0.50 for molybdenum, nickel and iron, respectively. In addition, the reaction mechanism for the dissolution of the metalliferous black shale was discussed.

Anti-ultraviolet aging tests of asphalts adapting to environment in Tibetan Plateau of China

Ultraviolet （UV） aging is one of the main factors which cause premature damage of asphalt pavements in the Tibetan Plateau, China. According to the measured levels of UV radiation, aging tests of styrene-butadiene rubber （SBR） asphalts with different contents of three anti-UV-aging agents including nano-TiO2, CeO2 and carbon black are performed. Common indices, which include retained penetration after thin film oven tests （TFOT） and softening point, and strategic highway research program （SHRP） indices of aged asphalts are evaluated. Infrared absorption spectral analysis is performed on asphalt specimens with 0. 8% carbon black which have been aged for different aging times （500, 1000 and 1 500 h）. By grey incidence analysis, the optimal contents of anti-UV-aging agents are determined. The results show that TiO2 and CeO2 are not only good UV absorbing or shielding agents, but also strong oxidants. Carbon black is a good anti-UV-aging agent, and its optimal content is about 0. 8% of asphalt weight. UV aging of asphalt mainly occurs in the early stages of aging. The longer the aging time, the more severe the aging of asphalt.

Activities of Urease and Phosphatase in Integrated Vertical Flow Constructed Wetland and Purification Effect of Black and Malodorous River

[Objective]The activities of urease and phosphatase in integrated vertical flow constructed wetland and purification effect of black and malodorous river were studied.[Method]Honeycomb stone and soft filler were used as matrix,the biological grid integrated vertical flow constructed wetland system was built to strengthen treatment for black and malodorous river,and the activities of urease and phosphatase of two fillers in different functional areas of constructed wetland were tested to study the film formation property of two fillers in different functional areas.[Result]Both urease and phosphatase activities on biofilm of soft filler were significantly higher than on biofilm of honeycomb stone filler;indicating that choosing soft filler was more advantageous to the growth of biofilm;and urease activity had significant correlation with total nitrogen removal rate,while phosphatase activity had no significant correlation with total phosphorus removal rate.[Conclusion]This study provided evidences for utilizing the activities of urease and phosphatase to evaluate the purification effect of black and malodorous river and choose appropriate filler.

Establishment and Optimization of Rye-specific PCR Reaction System

[Objective] The aim was to establish the optimal rye-specific PCR reaction system for rye.[Method] The ordinary wheat ＂Chinese Spring＂,S165,rye,octoploid triticale and hexaploid triticale were used as materials to carry out study on the effect of the amount of template DNA,primers,dNTPs,Mg2＋ concentrations,Taq DNA polymerase and annealing temperature on the rye-specific PCR reaction system of rye.[Result] The genomic DNA extracted by modified CTAB DNA extraction method showed high quality,which was satisfied for the PCR reaction template.The rye-specific PCR reaction system was 25 μl,including 10 × buffer solution,1.5 mmol/L MgCl2,200 μmol/L dNTP,40 ng primers,40-60 ng DNA template and 1 U Taq DNA polymerase.[Conclusion] The optimal rye-specific PCR reaction system was established,which provided basis for the identification of exogenous germplasm of rye in wheat background.

Recovery of titanium from undissolved residue(tionite) in titanium oxide industry via NaOH hydrothermal conversion and H_2SO_4 leaching

To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H2SO4 leaching for TiO2 preparation was developed. The experimental results show that under the optimum hydrothermal conversion conditions, i.e., 50% NaOH （mass fraction） solution, NaOH/tionite mass ratio of 4：1, reaction temperature of 240 ℃reaction time of 1 h and oxygen partial pressure of 0.25 MPa, the titanium was mainly converted into Na2TiO3, and the conversion was 97.2%. The unwanted product Na2TiSiO5 remained stable in water washing, and its formation was prevented by improving NaOH concentration. In water washing process, about 97.6% of Na＋ could be recycled by washing the hydrothermal product. The NaOH solutions could be reused after concentration. 96.7% of titanium in the washed product was easily leached in H2SO4 solution at low temperatures, forming titanyl sulfate solution to further prepare TiO2.

Investigation on Chemical Components of Higher Fungus Phellinus rhabarbarinus(Berk.) G. Cunn.

Five compounds including 2 benzene derivatives, 2 terpenoids and 1 sterol were separated by various separation methods such as positive silica gel, Sephadex LH-20 and Rp-18 gel from higher fungi Phellinus rhabarbarinus （Berk.） G. Cunn. Their structures were elucidated on the basis of nuclear magnetic resonance （NMR） spectroscopy and other methods. All the compounds were separated from this higher fungus for the first time.

Characteristic Change of Several Forest Landscapes Between 1896 and 1986 in Heilongjiang Province

Five forest landscapes in the maps of forest distribution in Heilongjiang Province in 1896 and 1986 were digitized and analyzed through GIS software. The results show that during the 90 years the total patch areas for Picea and Abies forest, Pinus sylvestris var. mongolica Litvin forest and Pinus koraiensis Sieb. et Zucc. forest had decreased about 87%, 40% and 84%, respectively. However, the total patch areas for broad leaved forest at the north of 51°N area had increased about 500%. The north frontier of broad leaved forest had moved towards northwest about 290 km. The fractal dimensions of Picea and Abies forest and mixed coniferous and broad leaved forest in 1986 were less than theirs in 1896, respectively. However, the fractal dimension of Pinus synvestris forest, Pinus koraiensis and broad leaved forest were more than theirs in 1896, respectively. Picea and Abies forest, Pinus synvestris forest, Pinus koraiensis and broad leaved forest became more fragmented. The transition percentages of Pinus sylvestris forest, Picea and Abies forest, Pinus koraiensis forest to themselves were less than the percentages to the mixed coniferous and broad leaved forest, respectively.

Catalytic oxidation of diesel soot particulates over Ag/LaCoO_3 perovskite oxides in air and NO_x

Ag/LaCoO3 perovskite catalysts for soot combustion were prepared by the impregnation method.The structure and physicochemical properties of the catalysts were characterized using X-ray diffraction,N2 adsorption-desorption,H2 temperature-programmed reduction,soot temperatureprogrammed reduction,and X-ray photoelectron spectroscopy.The catalytic activity of the catalysts for soot oxidation was tested by temperature-programmed oxidation in air and in a NOx atmosphere.Metallic Ag particles were the main Ag species.Part of the Ag migrated from the surface to the lattice of the LaCoO3 perovskite,to form La（1-x）AgxCoO3.This increased the amount of oxygen vacancies in the perovskite structure during thermal treatment.Compared with unmodified LaCoO3,the maximum soot oxidation rate temperature（Tp） decreased by 50-70 ℃ in air when LaCoO3 was partially modified by Ag,depending on the thermal treatment temperature.The Tp of the Ag/LaCoO3catalyst calcined at 400℃ in a NOx atmosphere decreased to about 140℃,compared with that of LaCoO3.Ag particles and oxygen vacancies in the catalysts contributed to their high catalytic activity for soot oxidation.The stable catalytic activity of the Ag/LaCoO3 catalyst calcined at 700℃ in a NOx atmosphere was related to its stable structure.

Research on Plantlet Rooting of Lagerstroemia indica

Tissue culture plantlets of Lagerstroemia indica were used to study the effects of different auxins on in-vitro rooting, and the effects of various media in transplanting of rooted plantlets and ex-vitro rooting. For in-vitro rooting of test-tube plantiets of Lagerstroemia indica, 0.5 mg/L IBA is a suitable growth regulator; in the case of transplanting of rooted plantlets, the medium ratio of peat soil to perlite at 7：3 is better; and as to ex-vitro rooting of Lagerstroemia indica plantlets, the medium ratio of peat soil to perlite at 3：7 is more suitable.

Dynamic of forest landscape in Heilongjiang Province for one century

With the help of GIS tool of ARC/INFO, ARCVIEW and FRAGSTATS, the map of forest resource distribution of Heilongjiang Province was analyzed in 1896, 1949 and 1981. Using total area, mean patch size, patch density, coefficient of patch size variation, mean patch fractal dimension and mean shape index, we studied the change of forest landscape pattern and the change of each patch types in this region. As a result, the total area of forest landscape and mean patch size decreased sharply, the quantity and density of patches increased, the juxtaposition of patches weakened, the shape of patch tended to become regular, and the border of patch simplified. All these showed that the forest landscape of this area tended to fragment gradually, and the fragment of Korean pine forest is the severest. The diversity of whole forest landscape and the evenness of landscape types distribution reduced gradually. Human impact, instead of climate change and forest community succession, is the most important reason for such dramatic changes.

Antioxidative effect of melatonin, ascorbic acid and N-acetylcysteine on caerulein-induced pancreatitis and associated liver injury in rats

AIM： To investigate the role of oxidative injury in pancreatitis-induced hepatic damage and the effect of antioxidant agents such as melatonin, ascorbic acid and N-acetyl cysteine on caerulein-induced pancreatitis and associated liver injury in rats. METHODS： Thirty-eight female Wistar rats were used. Acute pancreatitis （AP） was induced by two i.p. injections of caerulein at 2-h intervals （at a total dose of 100 μg/kg b.wt）. The other two groups received additional melatonin （20 mg/kg b.wt） or an antioxidant mixture containing L（＋）-ascorbic acid （14.3 mg/kb.wt.） and N-acetyl cysteine （181 mg/kg b.wt.） i.p. shortly before each injection of caerulein. The rats were sacrificed by decapitation 12 h after the last injection of caerulein. Pancreatic and hepatic oxidative stress markers were evaluated by changes in the amount of lipid peroxides measured as malondialdehyde （MDA） and changes in tissue antioxidant enzyme levels, catalase （CAT） and glutathione peroxidase （GPx）. Histopathological examination was performed using scoring systems. RESULTS： The degree of hepatic cell degeneration, intracellular vacuolization, vascular congestion, sinusoidal dilatation and inflammatory infiltration showed a significant difference between caerulein and caerulein＋melatonin （P= 0.001）, and careulein and caerulein ＋ L（＋）- ascorbic acid ＋N-acetyl cysteine groups （P= 0.002）. The degree of aciner cell degeneration, pancreatic edema, intracellular vacuolization and inflammatory infiltration showed a significant difference between caerulein and caerulein ＋ melatonin （P=0.004）, and careulein and caerulein ＋ L（＋）-ascorbic acid ＋N-acetyl cysteine groups （P=0.002）. Caerulein-induced pancreatic and liver damage was accompanied with a significant increase in tissue MDA levels （P= 0.01, P= 0.003, respectively） whereas a significant decrease in CAT （P= 0.002, P=0.003, respectively） and GPx activities （P= 0.002, P= 0.03, respectively）. Melatonin and L（＋）-ascorbic acid ＋N-acetyl cysteine administration significantly decreased MDA levels in pancreas （P= 0.03, P= 0.002, respectively） and liver （P= 0.007, P= 0.01, respectively）. Administration of these agents increased pancreatic and hepatic CAT and GPx activities. Melatonin significantly increased pancreatic and hepatic CAT （P= 0.002, P= 0.001, respectively） and GPx activities （P=0.002, P=0.001）. Additionally, L（＋）-ascorbic acid＋N-acetyl cysteine significantly increased pancreatic GPx （P= 0.002） and hepatic CAT and GPx activities （P= 0.001, P= 0.007, respectively） CONCLUSION： Oxidative injury plays an important role not only in the pathogenesis of AP but also in pancreatitis-induced hepatic damage. Antioxidant agents such as melatonin and ascorbic acid＋N-acetyl cysteine, are capable of limiting pancreatic and hepatic damage produced during AP via restoring tissue antioxidant enzyme activities.

Separation and recovery of copper in Cu-As-bearing copper electrorefining black slime by oxidation acid leaching and sulfide precipitation

A new hydrometallurgical route for separation and recovery of Cu from Cu-As-bearing copper electrorefining black slime was developed. The proposed process comprised oxidation acid leaching of Cu-As-bearing slime and selective sulfide precipitation of Cu from the leachate. The effects of various process parameters on the leaching and precipitation of Cu and As were investigated. At the first stage, Cu extraction of 95.2% and As extraction of 97.6% were obtained at 80 ℃ after 4 h with initial H2 SO4 concentration of 1.0 mol/L and liquid-to-solid ratio of 10 mL/g. In addition, the leaching kinetics of Cu and As was successfully reproduced by the Avrami model, and the apparent activation energies were found to be 33.6 and 35.1 kJ/mol for the Cu and As leaching reaction, respectively, suggesting a combination of chemical reaction and diffusion control. During the selective sulfide precipitation, about 99.4% Cu was recovered as CuS, while only 0.1% As was precipitated under the optimal conditions using sulfide-to-copper ratio of 2.4:1, time of 1.5 h and temperature of 25 ℃.

Changes of Soil Labile Organic Carbon in Different Land Uses in Sanjiang Plain, Heilongjiang Province

In the Sanjiang Plain,Northeast China,the natural wetland is undergoing a rapid conversion into agricultural land,which has resulted in drastic ecological changes in the region. To investigate the effects of different land uses on soil labile organic carbon,soils of Calamagrostis angustifolia wetland,Carex lasiocarpa wetland,dry farmland,paddy field,forest land and abandoned cultivated land were collected for measuring the contents of soil microbial biomass carbon (MBC),dissolved organic carbon (DOC),readily oxidizable carbon (ROC) and carbohydrate carbon (CHC). The results show that soil organic carbon contents follow the order: Carex lasiocarpa wetland>Calamagrostis angustifolia wetland>forest land>paddy field>dry farmland. The contents of MBC and DOC in Calamagrostis angustifolia and Carex lasiocarpa wetlands are significantly higher than those in other land use types. The contents of CHC and ROC are the highest in Calamagrostis angustifolia wetland and the lowest in dry farmland. The contents of all the labile organic carbon increase along with the years of abandonment of cultivated land. The ratios of MBC,DOC and ROC to SOC also follow the order: Carex lasiocarpa wetland>Calamagrostis angustifolia wetland>forest land>paddy field>dry farmland,while the ratio of CHC to SOC is paddy field>forest field>Carex lasiocarpa wetland>Carex lasiocarpa wetland>dry farmland. When natural wetlands were cultivated,the activity of soil organic carbon tends to reduce in some extent due to the disappearance of heterotrophic environment and the reduction of vegetation residue. Thus,the abandonment of cultivated land is an effective way for restoring soil organic carbon.

Catalytic Activity of the Black Liquor and Calcium Mixture in CO2 Gasification of Fujian Anthracite

CO2 gasification of Fuijian high-metamorphous anthracite with black liquor （BL） and/or mixture of BL and calcium stuff （BL＋Ca） as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressure. When the coal was impregnated with an appropriate quantity of Ca and BL mixture, the catalytic activity of CO2 gasification was enhanced obviously. With a loading of 8%Na-BL＋2%Ca, the carbon conversion of three coal samples tested reaches up to 92.9%-99.3% at 950℃ within 30min. The continuous formation of alkali surface compounds such as （[-COM], [-CO2M]） and the presence of exchanged Ca, such as calcium phenolate and calcium carboxylates （COO）2Ca, contribute to the increase in catalytic efficiency, and using BL＋Ca is more efficient than that adding BL only, The homogeneous model and shrinking-core model were applied to correlate the data of conversion with time and to estimate the reaction rate constants under different temperature. The corresponding reaction activation energy （Ea） and pre-exponential factor of three anthracites were estimated. It is found that Ea is in the range from 73.6 to 121.4kJ·mol^-1 in the case of BL＋Ca, and 74.3 to 104.2kJ·mol^-1 when only BL was used as the catalyst, both of which are much less than that from 143.5 to 181.4kJ·mol^-1 if no catalyst used. It is clearly demonstrated that both of BL＋Ca mixture and BL could be the source of cheap and effective catalyst for coal gasification.

Child-Pugh-Turcott versus Meld score for predicting survival in a retrospective cohort of black African cirrhotic patients

AIM: To compare the performance of the Child-Pugh-Turcott (CPT) score to that of the model for end-stage liver disease (MELD) score in predicting survival of a retrospective cohort of 172 Black African patients with cirrhosis on a short and mid-term basis.METHODS: Univariate and multivariate (Cox model) analyses were used to identify factors related to mortality. Relationship between the two scores was appreciated by calculating the correlation coefficient. The Kaplan Meier method and the log rank test were used to elaborate and compare survival respectively. The Areas Under the Curves were used to compare the performance between scores at 3, 6 and 12 mo.RESULTS: The study population comprised 172 patients, of which 68.9% were male. The mean age of the patient was 47.5 ± 13 years. Hepatitis B virus infection was the cause of cirrhosis in 70% of the cases. The overall mortality was 31.4% over 11 years of follow up. Independent factors significantly associated with mortality were: CPT score (HR = 3.3, 95% CI [1.7-6.2]) (P < 0.001) (stage C vs stage A-B); Serum creatine (HR = 2.5, 95% CI [1.4-4.3]) (P = 0.001) (Serum creatine > 1.5 mg/dL versus serum creatine < 1.5 mg/dL); MELD score (HR = 2.9, 95% CI [1.63-5.21]) (P < 0.001) (MELD > 21 vs MELD < 21). The area under the curves (AUC) that predict survival was 0.72 and 0.75 at 3 mo (P = 0.68), 0.64 and 0.62 at 6 mo (P = 0.67), 0.69 and 0.64 at 12 mo (P = 0.38) respectively for the CPT score and the MELD score.CONCLUSION: The CPT score displays the sameprognostic significance as does the MELD score in black African patients with cirrhosis. Moreover, its handling appears less cumbersome in clinical practice as compared to the latter.

Improved visible-light photocatalytic H_2 generation over CdS nanosheets decorated by NiS_2 and metallic carbon black as dual earth-abundant cocatalysts

CdS nanosheets(NSs)photocatalysts modified with dual earth‐abundant co‐catalysts of metallic carbon black(CB)and NiS2were synthesized by a two‐step solvothermal/impregnation method.Allthe experiment results demonstrated that the co‐loading of CB and NiS2could significantly enhance the photocatalytic H2‐evolution activity of CdS NSs.The photocatalytic performance of the as‐prepared CdS/CB/NiS2samples was tested under visible light(λ≥420nm)by using an aqueous solution containing0.25mol L–1Na2S‐Na2SO3as the sacrifice agent.The CdS‐0.5%CB‐1.0%NiS2composite photocatalysts exhibited the highest H2‐evolution rate of166.7μmol h?1,which was approximately5.16and1.87times higher than those of pure CdS NSs and CdS‐1.0%NiS2,respectively.The possible mechanism for the enhanced H2‐evolution activity of CdS/CB/NiS2composite photocatalysts was proposed.The results showed that the enhanced photocatalytic H2‐evolution activities could be ascribed to the co‐loading of metallic CB and NiS2as co‐catalysts onto the surface of CdS NSs.The excellent synergetic effect between the CB and NiS2could obviously improve visible light absorption,promote separation of photogenerated electron‐hole pairs and boost the H2‐evolution kinetics,thus leading to an enhanced activity for H2evolution.More interestingly,the metallic CB could not only act as a cocatalyst for H2evolution,but also serve as a conductive electron bridge to promote the charge migration.This work not only demonstrates that loading CB as a co‐catalyst is a promising strategy to further boost the photocatalytic activity of CdS/NiS2composites,but also offers a new mechanistic insight into the construction of highly efficient and stable CdS NSs‐based hybrid photocatalysts with dual earth‐abundant co‐catalysts for photocatalytic applications.

Effect of temperature on floatability and adsorption behavior of fine wolframite with sodium oleate

The influence of pulp temperature on the floatability and adsorption behavior of fine wolframite with sodium oleate was investigated by microflotation experiments, electric conductivity tests, adsorption measurements, and FT-IR analysis. Microflotation results show that fine wolframite with sodium oleate exhibits a good floatability at pH 8–9. Electric conductivity tests indicate that the high temperature enhances the ionization degree and electric mobility of oleate species, then the flotation recovery of fine wolframite and the adsorption amount of sodium oleate are observed to increase with the rise in pulp temperature. The results of adsorption experiments are found to meet Freundlich isotherms successfully, and the isosteric enthalpy （ΔH^Θ） is in conformity with the chemical bonding. The changes in FT-IR analysis provide sufficient evidence that sodium oleate interacts with the metal cations of wolframite surface, and the increase in pulp temperature clearly promotes the chemisorption intensity. These findings will be beneficial to strengthen the flotation behavior of fine wolframite.

Enhancement of the formic acid electrooxidation activity of palladium using graphene/carbon black binary carbon supports

Combinations of graphene(Gr)and carbon black(C)were employed as binary carbon supports to fabricate Pd‐based electrocatalysts via one‐pot co‐reduction with Pd2+.The electrocatalytic performance of the resulting Pd/Gr‐C catalysts during the electrooxidation of formic acid was assessed.A Pd/Gr0.3C0.7(Gr oxide:C=3:7,based on the precursor mass ratio)electrocatalyst exhibited better catalytic performance than both Pd/C and Pd/Gr catalysts.The current density generated by the Pd/Gr0.3C0.7catalyst was as high as102.14mA mgPd?1,a value that is approximately3times that obtained from the Pd/C(34.40mA mgPd?1)and2.6times that of the Pd/Gr material(38.50mA mgPd?1).The anodic peak potential of the Pd/Gr0.3C0.7was120mV more negative than that of the Pd/C and70mV more negative than that of the Pd/Gr.Scanning electron microscopy images indicated that the spherical C particles accumulated on the wrinkled graphene surfaces to form C cluster/Gr hybrids having three‐dimensional nanostructures.X‐ray photoelectron spectroscopy data confirmed the interaction between the Pd metal and the binary Gr‐C support.The Pd/Gr0.3C0.7also exhibited high stability,and so is a promising candidate for the fabrication of anodes for direct formic acid fuel cells.This work demonstrates a simple and cost‐effective method for improving the performance of Pd‐based electrocatalysts,which should have potential industrial applications.

Protective effect of melatonin against multistress condition induced lipid peroxidation via measurement of gastric mucosal lesion and plasma malondialdehyde levels in rats

AIM： To study the protective effect of a natural antioxidant, melatonin, against multistress condition induced lipid peroxidation v/a determination of gastric damage and plasma malondialdehyde （MDA） level by high performance liquid chromatography in rats. METHODS： We compared indomethacin-induced gastric damage and MDA plasma level in three groups of rats： unoperated, bile duct ligated and sham-operated and evaluated the role of the melatonin on gastric damage and plasma MDA level. Indomethacin and melatonin were injected intraperitoneally in doses of 50 mg/kg and 20 mg/kg, respectively. Animals were killed 4 h after indomethacin injection. RESULTS： Indomethacin induced more severe gastric damage and plasma MDA level in bile duct ligated animals was significantly higher （3.1±0.04 μmol/L） than sham （2.8±0.04 μmol/L） and unoperated animals （1.4±0.08 μmol/L）. Pretreatment with melatonin reduced indomethacin-induced gastric damage and plasma MDA level. CONCLUSION： Considering the results of this study, we suggest that in multistress conditions the intensity of gastric damage and the plasma MDA level are great and melatonin reduces the negative effect of lipid peroxidation and cell damage by oxidative stress in multistress conditions due to its antioxidizing activity.