The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil wer...The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu,Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form(31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions(27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions(90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code(RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd(45.6 and 54.4 %), medium risk of Zn(100 %), low and medium risk of Cu(41.2 and 58.8 %), largely no risk of Hg(97.1 %), and mainly low risk of As and Pb(92.6and 91.8 %). The range of the potential ecological risk of soil was 58.2–1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk.展开更多
A pure culture using benzene as sole carbon and energy sources was isolated by screening procedure from gasoline contaminated soil.The analysis of the 16S rDNA gene sequence,morphological and physiological characteris...A pure culture using benzene as sole carbon and energy sources was isolated by screening procedure from gasoline contaminated soil.The analysis of the 16S rDNA gene sequence,morphological and physiological characteristics showed that the isolated strain was a member of genus Bacillus cereus.The biodegradation performance of benzene by B.cereus was evaluated,and the results showed that benzene could be efficiently biodegraded when the initial benzene concentration was below 150 mg/L.The metabolites of anaerobic nitrate-dependent benzene oxidation by strain B.cereus were identified as phenol and benzoate.The results of substrate interaction between binary combinations for benzene,phenol and benzoate showed that the simultaneous presence of benzene stimulated the degradation of benzoate,whereas the addition of benzene inhibited the degradation of phenol.Benzene degradation by B.cereus was enhanced by the addition of phenol and benzoate,the enhanced effects were more pronounced at higher concentration.To our knowledge,this is the first report that the isolated bacterial culture of B.cereus can efficiently degraded benzene under nitrate reducing conditions.展开更多
Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical...Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.展开更多
The aim of this paper is to seek the numerical solution of a class of variable order fractional integral-differential equation in terms of Bernstein polynomials.The fractional derivative is described in the Caputo sen...The aim of this paper is to seek the numerical solution of a class of variable order fractional integral-differential equation in terms of Bernstein polynomials.The fractional derivative is described in the Caputo sense.Four kinds of operational matrixes of Bernstein polynomials are introduced and are utilized to reduce the initial equation to the solution of algebraic equations after dispersing the variable.By solving the algebraic equations,the numerical solutions are acquired.The method in general is easy to implement and yields good results.Numerical examples are provided to demonstrate the validity and applicability of the method.展开更多
For the treatment of brain ischemia using acupuncture, the needle is predominantly inserted into muscular layers and deep tissue. However, few studies have investigated the outcomes of shallow needling. The present st...For the treatment of brain ischemia using acupuncture, the needle is predominantly inserted into muscular layers and deep tissue. However, few studies have investigated the outcomes of shallow needling. The present study established middle cerebral artery occlusion models in rats using the thrombosis method. Shallow needling and conventional needling at the bilateral Neiguan （PC 6） and Gongsun （SP 4） acupoints improved neurological function of middle cerebral artery occlusion rats, increased the expression of the anti-apoptotic Bcl-2, inhibited the expression of the pro-apoptotic Bax, and reduced the expression of the vasoactive substances nitric oxide synthase and endothelin-1. However, these changes were more pronounced in the shallow needling group, indicating that shallow needling is more effective in inhibiting brain ischemic injury.展开更多
To contribute to the reduction of methane emissions,using low-cost biochar as adsorbents for capturing and storing methane in oil and gas fields is investigated.This work presents results of methane adsorption on four...To contribute to the reduction of methane emissions,using low-cost biochar as adsorbents for capturing and storing methane in oil and gas fields is investigated.This work presents results of methane adsorption on four biochars made from forestry wastes in comparison with the results of three commercial activated carbons.Although the adsorption capacity of the biochars is lower by over 50%than that of the activated carbons,thelow-cost and potential environmental benefits provide the incentive to the investigation.Moreover,it is shown that biochar can store more methane than vessels of compressed gas up to the pressure of 75 bar,suggesting the possibility of avoiding high-pressure gas compression and heavy vessels for cost savings in oil and gas fields.The thermodynamic and kinetic behaviors of the adsorption are studied and implications for the targeted application are discussed.展开更多
This study was conducted to evaluate the toxicological response ofp-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC50 was used to estimate the ...This study was conducted to evaluate the toxicological response ofp-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC50 was used to estimate the single and joint toxicity of the two chemicals. The toxicity of p-nitrotoluene was greater than that of pnitroaniline based on 96 h LCso values of 40.74 mg.L^-1 and 48.99mg.L^-1, respectively. Both compounds had moderate toxicity toward Cyprinus carpio, and this toxicity increased with the exposure duration and con- centration. Binary mixtures of the compounds were more toxic than the individual compounds at 96 h, and they acted upon partial addition. When the exposure time was longer, the toxicity increased for mixtures of compounds with the same concentration or toxicity. The results of this study suggest that exposure to a combination of these chemicals would result in a higher environmental risk in aquatic systems than exposure to either compound alone. Further research is needed to investigate the combined effects and sublethal toxicity of p-nitrotoluene and p- nitroaniline, since they are both still used in China.展开更多
基金funded by National Natural Science Foundation of China (No. 41303069)
文摘The soil pollution by heavy metals was characterized in the mine tailings and surrounding soils of an old Pb–Zn mine in Huize County. Three hundred and ninety-six samples of agricultural and non-agricultural soil were analyzed for the total metal concentration by acid digestion and sixty-eight selected soil samples were used to determine the chemical fractionation of heavy metals with the modified BCR sequential extraction method. The pollution index of the heavy metals indices for As, Cd, Cr, Cu,Hg, Pb and Zn of non-agricultural soil and agricultural soils in the study area indicated the spreading of heavy metal pollution. Sequential extraction showed that most of Cd existed in an exchangeable form(31.2 %). The available content of Pb, Cu and Zn was mainly distributed in acid extractable fractions and Fe/Mn oxide fractions(27.9, 30 and 27.2 %), and Hg, As and Cr were mainly associated with residual fractions(90.4, 72.9 and 76.8 %). The risks of heavy metals were also evaluated by the risk assessment code(RAC) and potential ecological risk index, respectively. The results of RAC showed a medium and high risk of Cd(45.6 and 54.4 %), medium risk of Zn(100 %), low and medium risk of Cu(41.2 and 58.8 %), largely no risk of Hg(97.1 %), and mainly low risk of As and Pb(92.6and 91.8 %). The range of the potential ecological risk of soil was 58.2–1839.3, revealing a considerably high ecological risk in the study area, most likely related to acid mine drainage and the mining complexes located in the area. The results can be used during the ecological risk screening stage, in conjunction with the total concentrations and metal fractionation values, to better estimate ecological risk.
基金supported by the National Natural Science Foundation of China (No. 40873076,40773055)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (No.2008890)
文摘A pure culture using benzene as sole carbon and energy sources was isolated by screening procedure from gasoline contaminated soil.The analysis of the 16S rDNA gene sequence,morphological and physiological characteristics showed that the isolated strain was a member of genus Bacillus cereus.The biodegradation performance of benzene by B.cereus was evaluated,and the results showed that benzene could be efficiently biodegraded when the initial benzene concentration was below 150 mg/L.The metabolites of anaerobic nitrate-dependent benzene oxidation by strain B.cereus were identified as phenol and benzoate.The results of substrate interaction between binary combinations for benzene,phenol and benzoate showed that the simultaneous presence of benzene stimulated the degradation of benzoate,whereas the addition of benzene inhibited the degradation of phenol.Benzene degradation by B.cereus was enhanced by the addition of phenol and benzoate,the enhanced effects were more pronounced at higher concentration.To our knowledge,this is the first report that the isolated bacterial culture of B.cereus can efficiently degraded benzene under nitrate reducing conditions.
基金National Basic Research Program of China (No. G1999043606)
文摘Calculation of the groundwater recoverable resource is the main part of groundwater resource evaluation. The three-dimensional groundwater flow model in Linfen Basin was established by GMS software. Then the numerical model was calibrated by observed groundwater level from February to December in 2 000. Based on the calibrated model, the groundwater recoverable resource is calculated. The simulation result shows that under the given value of the groundwater recoverable resource, the groundwater level would decrease significantly in the first 1 000 days, while the water level would drop slowly in 1 000 to 2 000 days, and the water level change tend to be stable after 2000 days.
文摘The aim of this paper is to seek the numerical solution of a class of variable order fractional integral-differential equation in terms of Bernstein polynomials.The fractional derivative is described in the Caputo sense.Four kinds of operational matrixes of Bernstein polynomials are introduced and are utilized to reduce the initial equation to the solution of algebraic equations after dispersing the variable.By solving the algebraic equations,the numerical solutions are acquired.The method in general is easy to implement and yields good results.Numerical examples are provided to demonstrate the validity and applicability of the method.
基金the National Natural Science Foundation of China, No. 3076031918
文摘For the treatment of brain ischemia using acupuncture, the needle is predominantly inserted into muscular layers and deep tissue. However, few studies have investigated the outcomes of shallow needling. The present study established middle cerebral artery occlusion models in rats using the thrombosis method. Shallow needling and conventional needling at the bilateral Neiguan （PC 6） and Gongsun （SP 4） acupoints improved neurological function of middle cerebral artery occlusion rats, increased the expression of the anti-apoptotic Bcl-2, inhibited the expression of the pro-apoptotic Bax, and reduced the expression of the vasoactive substances nitric oxide synthase and endothelin-1. However, these changes were more pronounced in the shallow needling group, indicating that shallow needling is more effective in inhibiting brain ischemic injury.
基金Program of Energy Research Development of Canada.
文摘To contribute to the reduction of methane emissions,using low-cost biochar as adsorbents for capturing and storing methane in oil and gas fields is investigated.This work presents results of methane adsorption on four biochars made from forestry wastes in comparison with the results of three commercial activated carbons.Although the adsorption capacity of the biochars is lower by over 50%than that of the activated carbons,thelow-cost and potential environmental benefits provide the incentive to the investigation.Moreover,it is shown that biochar can store more methane than vessels of compressed gas up to the pressure of 75 bar,suggesting the possibility of avoiding high-pressure gas compression and heavy vessels for cost savings in oil and gas fields.The thermodynamic and kinetic behaviors of the adsorption are studied and implications for the targeted application are discussed.
基金This study was co-funded by the National Natural Science Foundation of China （Grant No. 50979006）, Projects of Hebei Science and Technology Department （No. 12276708D）, Projects of Hebei Education Department （No. ZH2011119）, Natural Science Foundation of Hebei Province （No. D2010000867）, the Doctor Development Foundation Project in Hebei University of Science and Technology （No. 000446）, and the Key Discipline Foundation in Hebei Province.
文摘This study was conducted to evaluate the toxicological response ofp-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC50 was used to estimate the single and joint toxicity of the two chemicals. The toxicity of p-nitrotoluene was greater than that of pnitroaniline based on 96 h LCso values of 40.74 mg.L^-1 and 48.99mg.L^-1, respectively. Both compounds had moderate toxicity toward Cyprinus carpio, and this toxicity increased with the exposure duration and con- centration. Binary mixtures of the compounds were more toxic than the individual compounds at 96 h, and they acted upon partial addition. When the exposure time was longer, the toxicity increased for mixtures of compounds with the same concentration or toxicity. The results of this study suggest that exposure to a combination of these chemicals would result in a higher environmental risk in aquatic systems than exposure to either compound alone. Further research is needed to investigate the combined effects and sublethal toxicity of p-nitrotoluene and p- nitroaniline, since they are both still used in China.
