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Liao Y.,Nanjing Agricultural University | Liao Y.,Hunan Province Environmental Monitoring Center | Liang J.,Nanjing Agricultural University | Zhou L.,Nanjing Agricultural University
Chemosphere | Year: 2011

This study investigates synthesis of biogenic schwertmannite by Acidithiobacillus ferrooxidans and its role and mechanism in adsorption of As(III) from water. Results indicate that schwertmannite particles formed through oxidation of ferrous sulfate by A. ferrooxidans cells for different times vary greatly in size and in morphology. The hedge-hog like schwertmannite formed after reaction for 72h are aggregative spheroid particles with a diameter of approximately 2.5μm and its chemical formula can be expressed as Fe8O8(OH)4.42(SO4)1.79. Batche studies show that both Freundlich and Langmuir model are suitable for describing the adsorption behavior of As(III) on schwertmannite at pH 7.5 and As(III) in simulated groundwater can be effectively removed by biogenic schwertmannite with a maximum adsorption capacity of 113.9mg As(III) g-1 and the optimal pH is in the range of 7-10. The arsenic removal is hardly affected by the competing anions often observed in groundwater unless the mole concentration of PO43- and SO42- in groundwater are 75 or 750 times higher than As(III), respectively. The mechanism of As(III) adsorption on biogenic schwertmannite involves ligand exchanges between arsenic species and surface hydroxyl group and sulfate. In addition, experiments show that As(III)-sorbed biogenic schwertmannite aged in deionized water at 25°C exhibits no mineralogy phase changes even after ageing at pH 6.0 and 8.5 for 90d. © 2011 Elsevier Ltd. Source


Guo X.,Hunan University | Yang X.,Hunan University | Liu P.,Hunan Province Environmental Monitoring Center | Wang K.,Hunan University | And 6 more authors.
Analyst | Year: 2015

MicroRNAs (miRNAs) participate in various biological processes during the course of life. The levels of miRNAs can be useful biomarkers for cellular events or cancer diagnosis, thus sensitive and accurate analysis of miRNA expression is crucial for better understanding its functions and the early diagnosis of human disease. Here, we developed a multiple amplification detection method for miRNA based on the host-guest interaction between β-cyclodextrin polymer and pyrene, which takes advantage of the polymerase-aided strand displacement amplification and λ exonuclease-assisted cyclic enzymatic amplification. The proposed method allowed quantitative detection of miRNA-21 in a dynamic range of 1 pM to 5 nM with a detection limit of 0.3 pM and demonstrated good ability to discriminate the target sequence from the single-base mismatched miRNA sequence. Moreover, the assay was applied successfully in a complex biological matrix. We believe that this proposed sensitive and specific assay has great potential as a quantification method for miRNA detection in biomedical research and clinical diagnosis. © The Royal Society of Chemistry 2015. Source


Guo X.,Hunan University | Liu P.,Hunan Province Environmental Monitoring Center | Yang X.,Hunan University | Wang K.,Hunan University | And 6 more authors.
Analyst | Year: 2015

A multiple amplification strategy has been developed for nucleic acid detection based on host-guest interaction between the β-cyclodextrin polymer (β-CDP) and pyrene. Briefly, the detection system consists of three parts: the polymerase and nicking enzyme-assisted isothermal strand displacement amplification (SDA) activated by a target DNA or microRNA; the exonuclease III-aided cyclic enzymatic amplification (CEA); and the fluorescence enhancement effect based on host-guest interaction between β-CDP and pyrene. This strategy showed a good positive linear correlation with target DNA concentrations in the range from 75 fM to 1 pM with a detection limit of 41 fM. Significantly, our amplification platform was further validated and evaluated successfully by assaying miRNA-21 in human serum. The proposed assay has great potential as a nucleic acid quantification method for use in biomedical research, clinical analysis and disease diagnostics. This journal is © The Royal Society of Chemistry 2015. Source


Zhang Q.,Shandong University | Zhu R.,Hunan Province Environmental Monitoring Center | Kang Q.,Shandong University | Lu W.,CAS Yantai Institute of Coastal Zone Research | And 2 more authors.
International Journal of Electrochemical Science | Year: 2012

Cobalt hexacyanoferrate particles were ground with water-miscible room-temperature ionic liquid, 1-methylimidazolium trifluoroacetic acidic salts (HMImTfa), and resulted in HMImTfa-CoHCF gel. The electrochemical properties of HMImTfa-CoHCF gel were investigated in detail. The impedance data show that HMImTfa-CoHCF gel is mixed ionic-electronic and has 2.5 times the improvement of the conductivity than that of pure HMImTfa. HMImTfa-CoHCF gel can be used in chemically modified electrode for the electrocatalytic oxidation of NADH. The corresponding results have important implications for the design of nano-structured and nano-composite materials based on water-miscible room-temperature ionic liquids, which could be used widely in chemo/biosensing and catalysis. © 2012 by ESG. Source


Qin D.-L.,Hunan Province Environmental Monitoring Center | Qin D.-L.,State Environmental Protection Key Laboratory of Monitoring for Heavy Metal Pollutants | Wei A.-L.,Northwest University, China | Lu S.-Y.,Chinese Research Academy of Environmental Sciences | And 8 more authors.
Research of Environmental Sciences | Year: 2013

The equitable and reasonable allocation of the total permitted pollution discharge is the key to the load control of the total water pollutant. A specific assessment system of the water pollutant load allocation based on the environmental Gini coefficient method was established by taking the whole benefit of the social, economic and natural resources into account. The spatial distribution characteristics of the unfair factors in the area of Dongting Lake were also analyzed through selecting the contribution coefficient as a judge for unfair factors combined with the GIS technique. Additionally, the program of the total load allocation for water pollutants in the Dongting Lake area was proposed according to the minimized model of Gini coefficient. The research found that Gini coefficients of TN and TP based on both GDP and land area were higher than 0.2, which was over the reasonable limitation of the Gini coefficient. These higher Gini coefficients implied unfair pollutant discharge in the lake area. In addition, there were unfair features in different parts of the lake area. Among three large pollution control zones, zone I(pollution control zone of central cities) and zone III(ecological conservation zone of mountains/hills) offered the least land area contribution coefficients and the least green contribution coefficients, respectively, which implied the presence of the most significant unfair features in these two zones. To change the unfair status, the minization of Gini coefficients led to an optimization of pollutant discharge allocation in 2020 based on the data in 2008. In the optimized strategy of the total nitrogen discharge, zone I would have the reduction rate of 8.18%, which would be the largest among all the three pollution control zones. In addition, Yueyang City would have the biggest reduction amount of 865.0 t/a among all the twenty administrative units in the lake area. For the total phosphorus discharge, zone II(comprehensive improvement zone of plan agriculture) would have the largest reduction rate of 9.45%, and Huarong County would have the greatest reduction amount of 78.45 t/a. Source

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