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Wang L.,Shaanxi Environmental Monitoring Center | Wang L.,Xi'an University of Technology | Nie M.-Q.,Xi'an University of Technology | Yang X.-F.,Xi'an University of Technology | And 3 more authors.
Xi'an Jianzhu Keji Daxue Xuebao/Journal of Xi'an University of Architecture and Technology | Year: 2011

Two highly efficient degradation hydrophobic strains were successfully isolated and screened from the bottom sludge of coke-plant waste water by the PAH-sole-carbon source gradient concentration domestication. According to the analysis of its 16S rDNA gene sequence, CY4 strain was identified as Aeromonas salmonicida which was a new strain in PAHs biodegradation reports to the best of our knowledge, while HY7 was identified as Pseudomonas stutzeri which was seldom reported. The results indicated that the two strains could utilize extensive substrates, including PAHs intermediates such as salicylic acid, hybrid aromatic hydrocarbon such as indole, PAHs and glucose. And the five days pyrene degradation rate was up to 35.40% by CY4 strain and up to 36.32% by HY7 strain.

Wang C.,Northwest University, China | Zhang Q.,Northwest University, China | Zhang Q.,Shaanxi Environmental monitoring center | Cheng Y.,PLA Fourth Military Medical University | Wang L.,Northwest University, China
Biotechnology Progress | Year: 2010

Development of high efficiency and low cost protein refolding methods is a highlighted research focus in biotechnology. Artificial molecular chaperone (AMC) and protein folding liquid chromatography (PFLC) are two attractive refolding methods developed in recent years. In the present work, AMC and one branch of PFLC, ion exchange chromatography (IEC), are integrated to form a new refolding method, artificial molecular chaperone-ion exchange chromatography (AMC-IEC). This new method is applied to the refolding of a widely used model protein, urea-denatured/dithiothreitol-reduced lysozyme. Many factors influencing the refolding of lysozyme, such as urea concentration, β-cyclodextrin concentration, molar ratio of detergent to protein, mobile phase flow rate, and type of detergent, were investigated, respectively, to optimize the conditions for lysozyme refolding by AMC-IEC. Compared with normal IEC refolding method, the activity recoveries of lysozyme obtained by AMC-IEC were much higher in the investigated range of initial protein concentrations. Moreover, the activity recoveries obtained by using this newly developed refolding method were still quite high for denatured/reduced lysozyme at high initial concentrations. When the initial protein concentration was 200 mg mL -1, the activity recovery was over 60%. In addition, the lifetime of the chromatographic column during AMC-IEC was much longer than that during protein refolding by normal IEC. Therefore, AMC-IEC is a high efficient and low cost protein refolding method. © 2010 American Institute of Chemical Engineers.

Yang X.,China University of Technology | Yang X.,Xi'an University of Technology | Duan J.,China University of Technology | Duan J.,University of South Australia | And 5 more authors.
Environmental Monitoring and Assessment | Year: 2015

From data collected monthly at 26 monitoring cross sections in the Wei River in the Shaanxi Region of China during the period 2008–2012, the temporal pollution characteristics of heavy metals (Hg, Cd, Cr(VI), Pb, and As) were analyzed based on a heavy metal pollution index (HPI). The monthly HPI values of the five heavy metals in the river fluctuated greatly in 2008 and then declined gradually with time. This general trend of reduction in HPI appears not to have a seasonal variation and most likely resulted from the continued improvement in heavy metal pollution control strategies implemented by local environmental agencies combined with a significant improvement in wastewater treatment capacities. Among the five heavy metals, Cd and Pb were below 0.1 and 3 μg L−1, respectively, at all the sampling points in the studied areas in the year 2012. The detection rates of As, Hg, and Cr(VI) were in the order of Hg > Cr(VI) > As. Hg, Cr(VI), and As exceeded, in a month of the dry season in 2012, the standard limits for category III surface waters according to the China Environment Quality Standards for Surface Water (CEQSSW). Based on the assessment using the HPI method, the pollution status of these heavy metals in water of the Wei River in the Shaanxi Region was generally at an acceptable level, but exhibited distinctive characteristics between the main stream river and tributaries. Most of the tributaries were more seriously polluted than the main river. A health risk assessment was conducted based on the Human Health Risk Assessment (HHRA) method recommended by the United States Environmental Protection Agency (USEPA). Apart from As, the health risk for the five heavy metals in the region were at acceptable levels for drinking water sources (hazard quotient (HQ) < 1, carcinogenic risk (CR) ranged from 10−4–10−6) according to the Risk Assessment Guidance for Superfund (RAGS), USEPA. Arsenic was identified as the most important pollutant of concern among the five heavy metals; both its values of the HQ and CR indicated potentially adverse health risks for the local population. © 2015, Springer International Publishing Switzerland.

Gao C.,Chang'an University | Deng S.,Chang'an University | Jiang X.,Xian Institute of Geology and Mineral Resources | Guo Y.,Shaanxi Environmental Monitoring Center
Journal of Testing and Evaluation | Year: 2016

The current studywas based on annual ambient air qualitymonitoring data andcorresponding meteorological observation data of Xi'an in 2011. Distribution models on hourly concentrations of PM10, SO2, and NO2 were studied, and the results showed that statistical distribution functions varied from seasons and from pollutants. The optimal distributionmodels of PM10 concentrations in the four seasons (spring, summer, autumn, and winter) were generalized extreme value distribution (GEVD), Weibull, Weibull, and GEVD, respectively; those of SO2 were lognormal, loglogistic, log-logistic, and GEVD, respectively; and those of NO2 were Weibull, lognormal, GEVD, and GEVD, respectively. The concentrations rangeswere 0.03∼0.20mg/m3 for PM10, 0.008∼0.17mg/m3 for SO2, and 0.01∼0.12mg/m3 for NO2, and the probabilities of concentrations in the ranges for accordingly pollutantswere up to 85 %. Effects of the meteorological parameters on concentrations of PM10, SO2, and NO2 were studied with linear correlation analysismethod for Xi'an city. The results indicated that pollutant concentrations had a negative correlation with windspeed, temperature, and mixing height (MH), whereas it had a positive correlationwith atmospheric pressure and atmospheric stability. Both temperature and atmospheric pressurewere themost obvious correlation with SO2 concentrationwith r value of -0.7916 and 0.7032, respectively.Wind speed and MH had themost obvious correlationwith NO2 concentrationwith r value of -0.4423 and -0.3997, respectively. SO2 had the best correlationwithmeteorological parameters. Analyzing the statistical characteristics of urban air pollution concentration and their relationshipswithmeteorological parameters are of great importance to study urban air pollution problems and corresponding prevention measure. Copyright © 2014 by ASTM.

Yang X.,Xi'an Technological University | Yang X.,Xi'an University of Architecture and Technology | Wang L.,Shaanxi Environmental Monitoring Center | Guan J.,Shaanxi Environmental Monitoring Center | Duan J.,Xi'an University of Architecture and Technology
Chinese Journal of Environmental Engineering | Year: 2016

Based on monitoring data from the dry and rainy seasons in 2012, a comprehensive assessment of water quality in the Xi'an-Xianyang section of Weihe River was performed using principal component analysis (PCA) and multivariate linear regression of the absolute principal component scores (APCS-MLR). The results indicated that organic and nutrient pollutants were the major contaminants, and the river was also polluted by As, as determined by its background values. The pollution status of the Weihe River was more serious in the dry season than in the rainy season. The variation in the principal components and the cross-section comprehensive rankings between the dry and rainy seasons also indicated that rainfall might affect the water quality of the river. The cross-sections of the upstream portion of the river, located above the Zaohe River estuary, were less polluted than the corresponding downstream cross-sections. Furthermore pollution in the upstream section was mainly caused by sewage and industry discharge into the mainstream of the river. It was determined that the Zaohe River is becoming one the most polluted tributaries of the Weihe River. © 2016, Science Press. All right reserved.

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